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The analysis of geological materials, volume 2

1. 2 The sample tray and the waste bottles which col lect the acidic drains should be covered to prevent the acid vapour from escaping to the ambient air To ensure a clean air working environment good ventilation is recommended Method The method consists of the following techniques 1 Sample decomposition 2 Separation and concentration by hydride reduction 3 Measurement of selenium signal using Atomic Absorption Spectrometry 4 Calculation of selenium concentration based on a calibraton curve produced from known standard Solutions Apparatus Varian Model AA 6 atomic absorption spectrometer equipped with a model 9176 strip chart recorder Technicon Sampler II Technicon Proportioning PumpI Flow injection module Model No 1000 600 Lachat Instruments Gas liquid separator Gasimpinger Quartz tube 16 cm long 10 mm i d with an inlet tube fused into the centre wound with a 22 gauge Chromel A heating wire and insulated with a layer of wrapped Thermofab string Staco variable transformer Teflon beakers 30 ml Hot plate 18x 150 mm test tubes graduated at 15 ml Reagents Hydrofluoric acid HF 48 Perchloric acid 60 Hydrochloric acid HCl 38 Nitric acid HNO3 70 Digestion mixture Reducing solution Masking agent Stock selenium standard solutions 1000 g ml EA26 1 Selenium Procedures 1 Reagent preparation l l Digestion mixture
2. Polypropylene culture centrifuge tubes 50 ml graduated every 5 ml Disposable polypropylene culture tubes with caps 17 x 100 mm 16 ml capacity Hot plates Thermolyne 12 x 12 or equivalent Teflon PTFE stirring rods Test tube racks Polypropylene acid dispenser 500 ml Nalgene graduated cylinders 250 ml and 25 ml Reagents Hydrofluoric acid HF 48 w w Perchloric acid HCIO 60 w w Nitric acid HNO 69 w w Hydrochloric acid 37 w w Procedures 1 Sample Preparation for T1 Options and T2 Analytical Package HNO HF This is a mixed acid attack generally considered to provide a total decomposition and produce a solu tion for determination of trace elements by AAS or EA2 2 ICP OES is used to break down silicates in rocks soils and sediments 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 9 1 10 1 12 1 13 1 14 1 15 Prepare acid mixture to contain 100 ml of HCIO 50 ml of HNO and 400 ml of HF using a Nalgene graduated cylinder for measuring the HF volume Store in a clean polypropylene dispenser used to deliver HF acid see Note 1 Weigh 0 500 g of sample into a 50 ml PTFE beaker Add 15 ml of acid mixture see step 1 1 to the beaker using Nalgene labware for delivery Ensure complete wetting of the sample by swirling the beaker Place beakers on hotplates at 150 C and evaporate to dryness o
3. This method is used only where the sample matrix makes the constituents concerned unsuitable to be determined by XRF This will arise when the sulphur content of the rock is too high to allow a fused bead to be prepared by XRF This method is also applied for accurate determination where a standard reference material has to be analysed for certification purposes The method is applicable to most rock samples where Li is present in trace amounts 0 100 ppm A compound heated in a flame dissociates and the excited ions emit light of a characteristic wavelength The intensity of a given wavelength is proportional to the concentration of the source ion In the flame photometer the light produced falls on narrow band filters which reject all but the pertinent wavelengths These are transmitted to individual phototubes whose electrical outputs vary with light intensity and hence provide a measure of ion concentration Absolute measurements of light intensity by this method are affected by variations in flame condition and aspiration rate Sodium and potassium measure ments therefore require the introduction of another ion in a known concentration to provide a reference level Lithium is chosen because it emits light of a suitable wavelength and is not present in significant concentra tions in most rock samples The three electrical outputs are combined to produce two signals one proportional to the ratio of concentra tion of Na Li
4. solution 5ng Au mlin0 5 bromine in hydrobromic acid Procedures 1 Reagent preparation 1 1 0 5 bromine in hydrobromic acid pipet 1 ml of bromine into a 200 ml volumetric flask and make to volume with hydrobromic acid 1 2 0 1N HBr solution Add 6 ml HBr to 500 ml of distilled water in a one liter separatory fun nel Equilibrate with 25 ml of MIBK Discard excess MIBK Store in a stoppered glass con tainer EA22 1 Gold 1 3 1 4 5 v v solution pipet 10 ml of bromine into a 200 ml glass volumetric flask and make to volume with concentrated hydrochloric acid Cleaning solution mix nitric acid hydrobromic acid and distilled water in the ratio of 1 3 10 2 Standard Au solution preparation 2 1 2 2 2 3 1 ppm Au in 8 HCI prepare accurately by serial dilution of the 1000 ppm Au standard solution with 8 HCl 100 ng ml of Au in 8 pipet 5 ml aliquot of the 1 ppm Au solution into a 50 ml glass volumetric flask and make to volume with 8 5ng ml of Au 0 5 bromine hydrobromic acid pipet 2 5 ml aliquot of the 100 ng ml Au solution into a 50 ml glass volumetric flask Make to volume with 0 5 bromine in hydrobromic acid This solution is stable for 1 month 3 Extraction and preconcentration of the gold 3 1 3 2 3 3 3 4 3 5 3 6 3 7 EA22 2 Add 10 ml of 5 v v solution to the water sample in the polyet
5. 1 2 Dry samples are removed from the driers and systematically broken using a mechanical soil breaker and a mortar with a rubber pestle to avoid breaking individual particles 1 3 The sample is then passed through a number 10 2000 micron sieve and a sub sample MS4 2 1 4 1 5 1 6 1 7 1 8 1 9 1 10 weighing 50 g for sandy material or 100 g for silty or clay soils is retained in a 250 ml capped flint glass jar The remaining 10 mesh materialis retained and may be required for other tests 125 ml of the deflocculant solution see Reagents section for preparation is added to the sample and is allowed to soak into the sample ovemight The sample is then trans ferred to a mixing container and mixed with the jet mixer for 1 minute The sample is washed into a graduated cylinder which is then filled up to the level line with distilled water Before taking any readings each cylinder is covered with a rub ber stopper and systematically inverted for a period of 1 minute to completely mix the soil suspension with the water At the end of 1 minute the cylinders are set down and hydrometry readings are taken at the following time intervals measured from the beginning of sedimentation 2 5 15 30 60 and 240 4 hrs and 1440 24 hrs minutes The hydrometer scale would normally be read at the base of the meniscus but the soil suspen sion makes this impossible so the reading is taken at the
6. 6 3 5 Heat the covered crucible and contents at ap proximately 1100 C for 30 minutes cool in a desiccator for 30 minutes and weigh as Mg P O 6 3 6 Repeatthe ignition cooling and weighing until constant weight is obtained NOTE The ignited residue may now be corrected for cO precipitated manganese if this was not removed previously if it is present The manganese found is subtracted as Mn P 0 from the total weight of the pyrophosphate EA8 9 Majors Classical NOTE If Mnis determined in a separate sample using AA the Mg P O precipitate may be corrected for Mn as Mn P O assuming that all of the Mn was precipitated with the Mg Another alternative is to determine Mn by AA by dis solving Mg P O precipitate in Im purity of Ca can also be checked in this solution if present by AA Conversion Factors 0 3623 Mg P 0 MgO 2 7604 0 4998 205 MnO 2 0007 Mnj P 0 Mn 2 5831 uality control The determination limit for this method is 0 50 for all oxides This method is not used on a routine basis and only limited data are available to estimate precision and accuracy However a number of Stand ard Reference Materials SRMs have been analyzed by the Laboratories and the data contributed as part of the SRM certification program In every case the accuracy and precision have been outstanding Typi cally the reported Geoscience Laboratories data have been within 0 2 of the certifi
7. Additional standards run as a program check indicate the following values NIM L 54 58 GH 23 17 BEN 17 19 MRG 1 18 20 28 29 SY2 Counting statistics on the background of the VSN sample were used to calculate the detection limit at 3 4 ppm Determination limit was established at 5 ppm in the rock sample TANTALUM Literature Observed NIM S 25 Mica Fe 34 38 SY3 21 MAN 310 328 VSN 900 870 Tantalum agreement is poor at low levels however approximation at higher levels is adequate for correction purposes This program should not be used to determine Ta values instead use that outlined overleaf EA 16 8 Traces XRF Measurement program for the Determination of Tantalum XRF is used to determine tantalum in rocks to a determination of limit of 10 ppm Analytical parameters are found in PB DB GEORHO with measurement and link programs MP8 and LP8 and calculation parameters in CP8 Channel conditions for the elements are ELEMENT FLT COL DET XTL ORD UPL LWL ANGLE OFFS OFFS Rh Ka NO S 1 1 75 25 50 40 18300 Tal NO 1 65 35 75 40 44 375 NO 1 1 65 35 75 40 45 520 Cu S 1 1 65 35 75 40 44995 The two tantalum channels correspond to peak TA 1 and background positions TA2 The tantalum line lies between the copper Ka and nickel KB lines These two elements rarely occur in tantalum bearing rocks however they may be present in components of the X ray spectrometer and
8. Recovery of SiO from R O precipitate and determination by Flame Atomic Absorption Silica decomposition Add 1 0 g to the platinum crucible al ready having ignited R20 precipitate mix well with a small spatula and cover Fuse in a muffle furnace for 15 minutes at 1000 Place on a clean small silica tray Open the oven door and remove the crucible using platinum tipped tongs and place on another clean fused silica tray and cool it Place crucibles in a clean 250 ml nalgene beaker Place a small teflon coated stirring bar in the crucible Add 60 ml of 10 HF Add 100 ml of 4 5 boric acid solution Stir for 1 hour or more until dissolution is complete 3 5 10 Filter the solution using Whatman No 41 filter paper 12 5 cm into a 200 ml nalgene volumetric flask NOTE If iron is very high it is difficult to obtain a clear solution SiO will be attacked and will be in solution 3 5 11 Wash filter paper and beaker several times with small portions of distilled water Make to volume with distilled water This is your original solution 3 5 12 Pipet 50 ml of original solution to a 100 ml nalgene volumetric flask 3 5 13 Add 10 ml of 30 000 ppm Sr buffer solution to the flask and make to volume with distilled water 3 5 14 Determine SiO as described in the method Major Element Determinations by Flame Atomic Absorption page XXX 3 5 15 Add this SiO value to the value of pure SiO to
9. 0 5 and 1 0 ng ml Hg standard solutions are prepared by serial dilution of the 25 ng ml Hg solution with 2056 nitric acid These solutions are stable for at least two months Store solutions in a glass container 2 3 Sample decomposition 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 1 4 2 4 3 4 4 4 5 Weigh out 0 250 g of sample and transfer into a Pyrex No 7900 test tube Add 5 ml of concentrated nitric acid and 0 5 ml of concentrated hydrochloric acid to the sample Mix the contents Place the test tube in a well in the aluminum block When a batch of samples including the blank have been prepared in the same way place the aluminum block on the hot plate and maintain a temperature of 110 C Insert a thermometer in the small well in the aluminum block to monitor the temperature Digest the sample for two hours Add the 2 K Cr O solution dropwise to the sample with shaking until the orange color persists Place the test tube into a test tube rack or into another aluminum block and let cool at room temperature Add distilled water to the test tube and make to the 25 ml mark Mix the solution thoroughly using a vortex mixer Allow the residues to settle about one hour Transfer the supernatent sample solution to a sample cup for Hg determination Measurement of Hg concentration Tum on the power switch of the LDC Milton Roy Mercury Monitor and check that
10. 3 Sample decomposition acid digestion 3 1 Add by microburette 0 5 ml of 1 3 nitric acid to a 10x 75 mm test tube containing the silver bead obtained from the fire assay technique 3 2 After dissolution of the silver 0 5 ml of 1 3 hydrochloric acid is added and the contents mixed The AgCl precipitate is digested in the test tube and placed in an aluminum block on a hot plate 3 3 Heat until the supernatant solution is clear and the AgCl has coagulated as on the bottom of the test tube NOTE Do not heat so long that a loss of volume occurs through evaporation 3 4 To the acid mixture add 1 0 ml of distilled water using a microburette The test tube is then shaken and placed in the aluminum block to cool 3 5 Transfer a portion of the supernatant solution to a sample cup to determine gold platinum and palladium 4 Measurement of Au Pt and Pd concentrations Set up the Perkin Elmer 603 atomic absorption spectrophotometer equipped with an HGA 500 Programmer and Graphite Furnace and utilizing the AS 1 auto sampling system according to the procedure described in the manufacturer s operation manual The atomic absorption signal is measured with a Perkin Elmer Model 56 recorder The instrument parameters for each element are listed in the following table Instrument Parameters Au Pt Pd Lamp Current 8mA 12 16mA Wavelength 242 8nm 265 9nm 247 6nm Slit Width setting 0 7nm 4 0 7nm 4 0 2nm
11. 3 2 1 The crushed button is heated with 400 ml of 12 N HCL in a covered beaker on a hot plate in a fume hood until the sample completely dissolves 3 2 2 The solution is cooled and filtered under vacuum and washed with about 400 ml of distilled water It is imperative that all the hydrochloric acid is removed that includes any acid caught at the base of the vacuum filter apparatus The compositional character of the filter paper is very important Millipore SWP 047 00 SM type 5 micron 47 mm filter papers are best suited for this technique 3 2 3 The filter papers are folded twice The quad rant is then sealed inside special plastic using a bag sealing unit The bag is then itself sealed within another bag ready forthe irradia tion and counting procedure NOTE that it is important that all bag seals are good and stur dy this will avoid the escape of radioactive material from the bag during rough handling subsequent to the irradiation Fire Assay 3 3 3 Determination by INAA The PGE can be determined using a procedure involv ing two counts following Hoffman et al 1978 Rhodium and palladium can be determined during the first count and the remainder of the PGE during a second count Rhodium and palladium are determined by irradiation of samples serially for 5 minutes and then allowed to decay for 60 seconds so that the very short lived radioisotopes can decay Samples and standards were counted for 200 s for the 109mPd a
12. La Nd and Ce The method can be applied to a wide variety of aqueous samples Data may be biased due to the presence of numerous spectral interferences All of these inter ferences are quantifiable but may degrade the deter mination limits It is advisable to discuss the potential problems inherent in a specific sample matrix with the Supervisor Spectroscopy Subsection prior to the sub mission of aqueous samples Safety advisory Refer to the Trace 2 Package Method Refer to the Trace 2 Package The one major dif ference between these samples and the method as described earlier is that the dissolution digestion technique can be ignored Apparatus Refer to the Trace 2 Package Productivity Refer to the Trace 2 Package Additional Notes Refer to the Trace 2 Package EA18 24 Reagents Refer to the Trace 2 Package Procedures Refer to the Trace 2 Package Quality Control Determination Limits and Ranges for Elements in Aqueous Samples Element Range Element Range ppm ppm Sn 0 04 200 Mo 002 35 W 0 03 40 B 0 02 30 Zn 0 01 30 P 0 30 5000 Pb 0 40 500 Gd 0 04 15 Co 0 01 3 Ni 0 02 35 Ba 0 003 45 0 04 10 Sc 0 01 1 Mn 0 003 100 Cr 0 01 3 Fe 0 07 2800 Mg 0 15 3000 Sit 10 1200 V O01 4 Al 025 7000 00 2 Be 0 001 01 Ca 0 07 1200 Cu 0 004 100 Ag 0 025 3 Yb 0002 05 0 01 100 Zr 0 015 15 Dy 002 3 Sm 006 15 Y 0004 1 La 0 025
13. Productivity A technician should be able to complete up to 100 samples per day Additional Notes 1 Bead colour the presence of high concentrations ofthe platinum group elements may give the silver bead a dark grey colour 2 Bead shape flat silver beads usually contain some base metals i e zinc 3 Special assays assays of complex or unusual ores changes to the stock flux or standard assay method are often necessary with complex or un usual ores 4 In the standard assay the dilution of the pulp is approximately 1 5 However an unusual chemistry of the pulp can still result in anomalous results For example excess silica may cause precious metals to be lost by slagging or matte formation A knowledge of the pulp fluxes and reagents available will allow for the adjustment of the assay process to give accurate and reproducible results 5 Other assays bullion umpire and fraud case as says these categories of assay although identical to the regular gold and silver assays or special assays require replicate analysis 6 The various reagents fluxes reducing oxidizing and desulphurizing agents and processes used during regular fire assay work are A Acid fluxes such as silica SiO and borax glass Na B4O for use with basic ores B Basic fluxes such as sodium carbonate NaCO and litharge PbO for use with Silicic ores C Oxidizing agents such as potassium nitrate used with st
14. 0 OEO Na 40 last channel 0 OEO EA6 21 Majors XRF The final MP should look like the one printed below and accessed from the computer by instruction PMP 1 PMP 1 MP 1 MASK x ABS YE CHAN PT PC K 40 OEO Fe 20 OEO Mn 10 OEO Mn 40 OEO Ti 40 OEO Ti 10 OEO Ca 20 OEO Si 40 OEO Al 40 OEO P 40 OEO P 10 OEO Mg 10 OEO Mg 40 OEO Na 10 OEO Na 40 OEO When a measurement instruction is given the system will slew to the K position first channel on list count for 40 seconds then continue on the Fe position If there is more than one sample in the turret each sample will be measured at the K channel first before changing to the next channel If the operator wishes to see the raw intensity counts the instruction PIN Print Intensity should be entered before the measurement instruction is given Rate Correction The MP for the major elements shown above allow for background correction using the offset position This is only one of the ways in which the count data can be corrected or adjusted The three principal rate corrections that can be applied are subtraction of a constant count rate subtraction of count rate taken at an offset position or at any other channel position interference ratioing to count rate at another channel The RC Table If the count rate at any given position channel contains a constant contribution from the spectrometer background sample cup additive to samp
15. 1 Duplicate determinations are checked for precision A discrepancy may be due to in homogenity of the sample incomplete decomposi tion caused by acid resistant minerals contamination loss of instrument control or dilu tion errors Each source of potential problem is investigated If the problem is identified as one that may have affected all samples in a batch the entire batch must be rerun If the problem is clearly identified as affecting only the one sample it is repeated and the whole batch need not be rerun Determined elemental values are checked with values obtained by the Screen program to indicate the possible presence of acid resistant minerals Pay particular attention to those samples which have been flagged by the sample preparation group as containing undecomposed material after acid digestion If an inconsistency is indicated the sample is redecomposed using an appropriate fusion method Evaluation of quality control data is monitored by the instrument operator and kept for the Supervisor s attention Screen Evaluation Values obtained with the XRF Screen program are approximate Protocols 2 Check the standard reference materials run with each Screen program to determine the accuracy obtained 3 Adjustanalytical values obtained for each sample using the reference material values For example if a SRM containing 800 ppm Ba yields a result of 500 ppm with the Screen program all Ba screen values
16. 1 1 for calcite CO MgO 1 1 for magnesite SO Na O 1 1 for themardite d F Ca O 2 1 for fluorite ei K 0 1 1 ii 1 1 iii combine i and ii to give K O AI1 03 Al 03 Na 0 1 3 for neph eline MS 16 1 ALKNOrMm iv residual K O AL O for kalsilite leucite or orthoclase v residual Na 0 AL50 for camegieite al bite f residual Na O Fe O 1 1 for acmite g residual Al O3 CaO 1 2 for gehlenite h residual for corundum i residual Na O for Na SiO j TiO CaO 1 1 for sphene or pervoskite or rutile if no CaO k If FeO remaining CaO then allot excess FeO Fe 0 1 1 for magnetite if not then continue to 12 1 FeO MgO CaO 1 1 for diopside the ratio of MgO and still available FeO is calcu lated and is maintained in 12 13 and any akermanite subsequently formed m residual FeO MgO for olivine n Fe 0 residual CaO 1 3 for andradite residual Fe O for hematite or residual CaO for wollastonite 4 Allot silica to make the following normative minerals MS 16 2 A In 3 3Na 0 K 0 4AL 03 8Si0 for nepheline In 3 1 0 2810 for kalsilite In 3 Na 0 A10 2SiO for camegieite D In 3 Na O Fe 03 4SiO for acmite In 3 2CaO A1 03 SiO for gehlenite F In 3 Na O SiO for Na SiO G In 3 3CaO Fe 03 3SiO for andradite H In 3 CaO SiO for wollastonite wol I In3 2 MgO FeO SiO for olivine f
17. 1000 10 Sc 2 2 100 5 V 5 5 500 10 Y 5 5 1000 20 Zn 5 5 1000 10 Options Ce 35 35 3000 70 La 2 5 2000 10 Nb 5 5 500 10 Nd 25 25 2500 50 Sr 5 5 10000 15 W 50 50 500 100 Precision is quoted as the 95 Confidence Limit ppm for a value at 10X the determination limit pletely disconnected from the instrument DO NOT ATTEMPT TO GAIN ENTRY TO THE POWER GENERATOR WITHOUT PROPER TRAINING Other areas are protected by interlocks DO NOT OVERRIDE INTER LOCKS 2 Twotypes ofelectromagnetic radiation are of con cern radio frequency and ultraviolet Radio fre quency radiation has no known teratogenic effect but can cause somatic damage and could affect eyesight by the absorption of radiation by the fluids of the eye causing a damaging increase in pressure within the eye It is important to ensure that the plasma torch compartment is well shielded by inspecting the viewing and access ports Operate the instrument with the door closed to make sure that the RF radiation cannot escape The power transfer cable should be inspected to ensure that it is a tight fit and that no corrosion has occurred at the connecting points on both the in strument and on the plasma power generator EX PERIENCED TECHNOLOGISTS Ultraviolet radiation is emitted by the plasma THE PLASMA SHOULD NEVER BE VIEWED DIRECTLY Even light from the plas ma which is reflected from the source housing has a high level of ultraviolet radiation and
18. 2 Fusion with Sodium Peroxide Sodium peroxide Na O is used to decompose sili cate rocks containing spinels zircons arsenides and sulfides and tungsten niobium and tantalum minerals and rare earth phosphates This procedure is used primarily when chromium as chromite is present at concentrations gt 5 percent 2 1 Weigh 0 100 g of sample into a low form zirconium crucible 2 2 Add 0 600 g of sodium peroxide and mix by shaking or rotating the crucible carefully 2 3 Place the covered crucible on a silica tray and fuse in a muffle furnace at 650 C for 10 minutes 2 4 Remove crucible from furnace and cool 2 5 Hold the crucible with tongs while cleaning the crucible bottom with distilled water 2 6 Place crucible and fused contents into a 250 ml beaker and cover with a watch glass 2 7 Add 50 ml of distilled water and 10 ml of concentrated HNO very carefully 2 8 Using a hotplate heat for about 15 20 minutes until dissolution is complete 2 9 Remove the crucible using teflon coated crucible tongs and wash the crucible with a fine jet of distilled water collecting the wash ings in the beaker Sample Dissolution 2 10 Cool and transfer to an appropriate size 2 11 Submit solution for determination of volumetric flask minimum volume 100 ml chromium by AAS See section Trace Ele ments Determined by Flame Atomic Absorp tion EA2 10 Graphite Furnace GRAPHITE FURNANCE OPERATING PROCED
19. 3 15 8 37 10 2 4 15 6 38 10 1 5 15 5 39 9 9 6 15 3 40 9 7 7 15 2 41 9 6 8 15 0 42 9 4 9 14 8 43 9 2 10 14 7 44 9 1 11 14 5 45 8 9 12 14 3 46 8 8 13 14 2 47 8 6 14 14 0 48 8 4 15 13 8 49 8 3 16 13 7 50 8 1 17 13 5 51 79 18 13 3 52 7 8 19 13 2 53 7 6 20 13 0 54 7 4 21 12 9 55 T3 22 12 7 56 7 1 23 12 5 57 7 0 24 12 4 58 6 8 25 122 59 6 6 26 12 0 60 6 5 27 11 9 61 6 4 28 11 7 62 6 3 29 11 5 63 6 1 30 11 4 64 5 9 31 11 2 65 5 8 32 11 1 66 5 6 33 10 9 67 5 5 MS4 5 Grain Siz Anatysi5 1 3 E KR cQ P siso 058 225 6 O RENS eue i ni gt FE 6 oaks gt i g Q Jo Q SISA eo e o 11 pe j N gt lt 3 AS o ccm ZEE a RIS 9 8 5 Die x E p E EX a ioe a 070 ara rey s 213 MEE pan Aad peuicdey neg 222250 Figure GSAS MS4 6 Grain size Analysis 1 100 90 80 3 Cumulative percent nes e 8 SI ee 100 1000 10000 Grain size CASE ware wire Figure GSA1 Grain size analysis comparison of CLOGS case 2 and BARRINGER case 1 MS4 7 Grain size AnaLysts 1 Compile data into one grain size distribution Figure GSA2 Flow chart for grain size distribution calculation MS4 8 UTULtn 51 ARGtyM3 z METHOD 2 GRAIN SIZE ANALYSIS BY PARTICLE SIZING This method involves the use of both modified ASTM
20. 41 and 42 Bunsen bumer Meker burner Muffle furnace Hot plate Thermofab cloth Silica tray Graphite crucibles 32 X 29 mm 9 ml Teflon coated stirring bars Magnetic stirrers Nalgeneware 100 ml and 200 ml volumetric flasks 250 ml beakers and 100 ml graduated cylinder Reagents Sodium carbonate anhydrous NaCO Lithium Metaborate anhydrous LiBO Boric acid crystals Concentrated hydrochloric acid HCl 36 5 3896 Concentrated nitric acid HNO 69 0 71 0 Concentrated hydrofluoric acid HF 48 Concentrated sulphuric acid 504 96 Strontium nitrate ST NO4 Ammonium hydroxide HN4OH 28 30 Ammonium oxalate crystals NH4 C O H O Ammonium chloride crystals NH CI Diammonium phosphate crystals Ammonium nitrate NH4 NO4 Method The method consists of the following techniques 1 Fusion and decomposition of the sample by acid digestion 2 Precipitation of SiO R20 CaO and MgO 3 Separation of SiO R203 CaO and MgO 4 Weighing of SiO R O CaO and MgO 5 Calculation of results NOTE R represents a group of elements AI Fe Ti and P which are precipitated as the hydrated oxide by means of ammonium hydroxide in the presence of ammonium chloride Am monium chloride is added to prevent the precipitation of Mg OH Majors Classical Procedures 1 Reagent preparation 1 1 L2 1 3
21. 7 Shutting down 7 1 Aspirate distilled water for ten minutes It is important that this be done consistently be cause it will normally make it unnecessary to clean the atomizer chamber If however the chamber does become clouded wash it with soap and water only 7 2 Close gas tank and wait for flame lamp to extinguish 7 3 If a manual drain is fitted to the air filter open this and allow condensed moisture to blow off 7 4 Tum power off 7 5 If central air supply is being used close the air valve 7 6 Place cup of distilled water on the sample tray and leave aspirator needle immersed 8 Maintenance 8 1 Clean aspirator tube weekly Use filament provided 8 2 Clean glass chimney monthly Wash with detergent Check light filters at the back of the chimney compartment Wipe with lense paper 8 3 Check burner for encrustation Clean when required 8 4 Check aspirator rate frequently 1 5 1 7 ml min 8 5 Bleed moisture off compressor periodically uality control The determination limits are 0 15 for Na O and 0 1296 for K O using a 0 125 g sample and making to 250 ml Only limited quality control data are available for the estimation of accuracy and precision The Geoscience Laboratories has participated in a number of certification programs and SRMs SY 2 SY 3 MRG 1 AL 1 AN G and BEN have been analysed using this method The results Table are consistent with an estimated pr
22. Anisotropism When the polished surface of a cubic mineral is ex amined under crossed polars it is found to remain in extinction in all positions of the stage whatever the crystallographic orientation it is said to be isotrophic Variation in the colour of anisotropic minerals when the stage is rotated can cautiously be used as an aid in identification MS9 4 11 Internal reflections Some minerals examined in polished section are transparent and others opaque Internal reflections are observable in the more transparent of the opaque minerals 12 Hardness Polishing and scratch hardness are useful tools in the identification of opaque minerals To observe the polishing hardness the KALB light line is used Shel ley 1975 To observe this line focus on the boundary line between two mineral grains lower the stage so that the sample begins to go out of focus and observe a line of light which will move towards the softer mineral provided there is significant relief 13 Structural and morphological properties Crystal form and habit are recognizable in reflected light Some minerals form well developed crystals euhedra whereas others are anhedral All of the standard terms used for transmitted light can also be used Cleavage and parting are sometimes seen in polished surfaces as rows of triangular pits Twinning of crystals is often observed in reflected light Bibliography Shelley D Manual of Op
23. CaO 0 15 0 15 0 50 0 4 P205 1 0 05 0 1 0 02 TiO2 0 3 0 12 0 1 0 02 MnO 0 1 0 015 0 1 0 02 LOI 04 8 0 4 0 4 8 0 4 CO2 0 1 4 0 1 0 1 4 0 1 S 0 03 2 0 02 0 03 2 0 02 FeO 0 2 10 0 2 H20 01 6 02 H20 0 05 1 0 1 During fusion any FeO in the sample is converted to by the reaction 2FeO O Fe 0 As the reaction proceeds the sample gains weight the weight gained is equal to 0 111 x FeO The true ignition loss CORLOI is therefore CORLOI LOI 0 111 FeO and is compared to the total volatile content The concentration of in the sample is equal to the difference between the total iron measured in the sample by XRF and the FeO contribution Fe O Total Iron as Fe O 1 111 x FeO Each sample is identified by sample number batch identifier and batch number Reports are double checked for agreement in duplicates and totals before being submitted to the Section Supervisor Quality Control It is important to distinguish between short term batch precision and long term multi year precision The Ontario Geological Survey carries out many multi year projects The analytical data used in the resulting report can come from rocks collected and submitted for analysis over a period of several years For the geological interpretations to be significant they must be based on a realistic evaluation of the long term precision One of the Laboratories blind duplicate q
24. Changes are allowed at this point 3 The number of T2 elements to be reported If less than 11 T2 elements are requested for a job the user will be asked to enter the required number of elements for that job If W is included in the T2 package enter 11 for the number of T2 elements otherwise enter 10 4 The name of the analyst 5 The report date Change the paper to 14 7 8 x 11 and position the print head at the last line position of the page Vertical and horizontal pitches on the DEC terminal have to be changed to 6 and 8 respectively When all this has been done press the RETURN key and the program will printout all of the jobs on a T2 form that is ready to be reported EA18 23 iraces ICP OES AQUEOUS SAMPLES ANALYSIS PACKAGE INDUCTIVELY COUPLED PLASMA SOURCE EMISSION SPECTROSCOPY Introduction A general introduction to the principles of ICP source emission spectroscopy is given in the Overview to Trace Element Determination by ICP Optical Emis sion Spectroscopy An explanation of potential inter ferences and procedures for dealing with these is also presented The Geoscience Laboratories is able to accept aqueous samples for analysis on the JY48P ICPOES Spectrometer No sample preparation is required and simultaneous determination of up to 36 elements is possible The available elements are Sn Mo W B Zn P Pb Co Ba Sc Cr Mg V Nb Ca Ag Ti Dy Y Eu Sr Gd Ni Ta Mn Fe Si Al Be Cu Yb Zr Sm
25. Insert the reagent tubes into the corresponding solutions see arrangement in Figure Sel As soon as the system has stabilized and the baseline is established the standard and sample solutions which have been loaded in the sampler can then be run sequentially In position 1 of Figure Sel the sample solution is picked up from the sample cup and is drawn through the sample tubes line 4a and 4 in Figure Sel by the action of the peristaltic pump It enters port A of the injection valve filling up the sample loop AB and the excess exits through port B The rotor of the injection valve then rotates a quarter turn so that ports A and B interchange places with ports C and D position 2 Figure Sel permitting the sample solution in the loop AB to be propelled by the 5 carrier into the reacting stream At the same time the sample probe swings into the sample reservoir in a synchronized motion with the rotor The solution in sample line 4a which is now 5 HCI enters port C and exits through port D This flow will flush out the tailings of the sample solution in preparation for a new cycle of sampling 5 Calculation of the results When the analysis is complete calculate the Se con centration from a calibration plot of peak height vs concentration which is linear up to 4 ng Se ml Read the concentration of Se in the sample solution from the calibration graph Subtract the blank value to obtain the net concentration ng Se
26. Ir Ru Os Au Precision 20 values quoted by Hoffman et al 1978 based on multiple analysis of an internal standard L S 4 are TABLE FAS Standard SARM 7 MRB 19 MRB 20 MRB 21 MRB 22 MRB 23 MS 14 6 Determination Limit ppb ONWOWNO Au ppb 310 269 5616 2810 200 s count 200 s count 2500 s count 5000 s count 5000 s count 5000 s count 5000 s count Pt ppb 3740 1395 69872 23551 31643 TABLE FA4 PRECISION 20 Element Rh Pd Pt Ir Os Ru Au Pd ppb 1530 1784 1154 243929 71219 90126 Concentration ppb Os ppb 135 320 290 75 30 150 42 Ir ppb Precision 46 Ru ppb 43 65 108 730 25 339 Accuracy may be judged with reference to the ex pected values of SARM 7 and with reference to the results for the MRB series standards These values expressed in ppb are shown in Table FAS Rh ppb 24 228 149 2362 5876 915 Fire Assay 3 um Py co 926 ol u De 50 mm approx Figure FAI MS14 7 NORMATIVE PROGRAMS Introduction The CIPW system of rock classification was formu lated about the turn of the century by Whitman Cross Joseph Iddings Louis Pirsson and Henry Washington The system recalculates the bulk chemical composi tion of a rock into a hypothetical assemblage of stand ard normative minerals The calculation of the norms for d
27. Mix hydrofluoric acid perchloric acid nitric acid and distilled water in the ratio of 4 4 1 1 respectively and store in a polyethylene bottle 12 Reducing solution Dissolve 5 g of sodium borohydride and five pellets of sodium hydroxide in 500 ml of distilled water Store in a refrigerator when not in use The solution is stable at 4 C for at least a week 1 3 Masking reagent Dissolve 1 g of 1 10 phenanthroline in 100 ml of 0 1M HCl 2 Standard Se solution preparation 2 1 Stock Se Standard Solution 1000 g ml Dis solve 0 100 g of powdered selenium in 100 ml of 10 nitric acid 2 2 Working standard solutions Prepare 0 25 0 50 1 0 2 0 and 4 0 ng ml solutions by serial dilution of the stock standard solution with 3 6N HCI 3 Sample decomposition 3 1 Digest 0 200 g of rock sample with 5 ml of digestion mixture in a 30 ml teflon beaker on a hot plate for about one hour or until white fumes of perchloric acid appear and the volume of the contents reduces to approximately 1 ml 3 2 Cool and add about 2 ml of distilled water and 4 5 ml of concentrated HCI 3 3 Heat the contents to just under boiling for several minutes to reduce Se that is in Se oxidation state to Se 3 4 Cool and transfer the contents to a test tube calibrated at 15 ml 3 5 Make to volume with distilled water 3 6 Seal the test tube with a piece of Parafilm and mix the solution thoroughly The concentra tion of HCl in the sam
28. Rocks which crystallize early contain small amounts of calcium periodotites dunites Sucessive crystallization forms calcium rich feldspars Calcium containing silicate minerals in clude augite hornblende amphiboles and the plagioclase feldspars Final crystallization occurs from a calcium depleted magma resulting in rocks with less calcium granite rhyolite Calcium carbonate minerals include calcite and aragonite CaCO and dolomite CaMg CO Non silicate minerals of calcium include the sulphates gyp sum CaSQ 2H 0 and anhydrite CaSQ fluorite CaF perovskite CaTiO and scheelite CaWO Magnesium Magnesium seventh in abundance in earth s crust can constitute as much as 51 percent as MgO in certain silicate rocks dunite or 30 to 40 percent in ultrabasic rocks picrites and peridotites Magnesium content decreases in the order dolerite gabbro basalt gt andesite gt granodiorite tonalite gt granite During crystallization of ferromagnesian minerals the first solid fractions are enriched in mag nesium relative to the composition of the magma the last fractions are enriched in iron Magnesium carbonate minerals include magnesite MgCO and dolomite CaMg CO Majors AA Manganese Manganese has an average crustal abun dance of 600 ppm The highest manganese contents occur in the earliest rocks to crystallize peridotites basalts and gabbros Granites and rhyolites contain only very small amounts o
29. SA signal contribution from analyte CM sol concentration contribution to analyte from matrix SUM x Cj Rock equivalent concentrations are obtained by CA rock CA sol X DF where DF dilution factor normally DF 100 for 0 5 g sample in final volume of 50 ml If we accept a realistic error of 5 RSD in the analyte and interferent intensities then the upper concentra tion limit in the apparent solution concentration CA sol will be equal to CA sol 1 1 0 05 SA AO 1 0 05 CM Traces ICP OES and the error E will be E CA sol CA sol 1 0 05 0 005 CM Similarly the lower concentration limit CA sol can be evaluated and the error E defined as CA soD CA soD A1 0 05SA 0 05CM The practical detection limit of the analyte PDL be defined as twice the error in CA sol or more simply PDL E E E E I 0 1 A1 SA 0 1 In the absence of any interference CM 0 the analyte contribution to the practical detection limit of the analyte PDL A can be defined as PDL A 0 1 A1 SA In the absence of analyte the matrix contribution to the practical determination limit of the analyte PDL M can be defined as PDL M 0 1 CM Error in the determination of the matrix interferents and in the subsequent contribution of this error to the error in the observed analyte concentration will affect the overall PDL or
30. Setthe sampling time at 30 sec and the wash ing time at 90 sec on the sample valve control ler 4 4 Place the calibration standards and sample solutions in the sample tray in order 4 5 As soon as the system has stabilized and the baseline established turn on the sampler The standard and the sample solutions can then be run sequentially The mechanisms of flow injection analysis In performing flow injection analysis samples and carrier are alternatively pumped into and flushed out of the sample loop which is mounted on the valve of the flow injection module The sample loop is 56 cm long and 0 97 mm in diameter Sampling time is 30 sec and flushing time is 90 sec The connection of these components and the analytical system are shown in Figure In position 1 sampling of Figure Cll the sample solutionis picked up from the sample cup and is drawn by the action of the proportioning pump It enters through port A of the injection valve filling the sample loop BC and the excess exits through port D and drains out as waste The sample flow path follows ABCD direction while the flow path of the carrier 6 HNOs is EF in order The rotor of the injection valve then rotates 60 degrees and turns into position 2 injection changing the flow paths to AD and ECBF respectively This permits the sample solution which has been col lected in the loop BC to be propelled by the 6 HNO carrier into the reacting stream At the
31. The cursor can be moved through the various fields by entering R 2 1 2 Nebulize a solution containing 80 ppb REEA Traces ICP MS 2 1 3 Press R1 The second page of the Spectrum Display software Measurement Settings will appear 2 1 4 Move the cursor and change the displayed fields to match those listed in Table MS3 2 1 5 Press R1 again The Mass Selection page should appear NOTE The Elan software relies on the use of a color coded numeric keyboard In the procedures described here the following short forms for references to operator responses using this keypad the keys are numbered left to right 1 2 and 3 G Grey R Red Y Yellow B Blue and Gn Green Scanning 2 1 6 Enter 139 Enter 139 again The Elan will scan over this mass range the 139La peak 2 1 7 Press G3 to start the scan 2 1 8 Press R in response to the prompt Press or Abort to continue 2 1 9 Press G1 to get into Graphics mode 2 1 10 Press and hold the FUNCT key down While this key is depressed press Gn3 This will engage the crosshair markers 2 1 11 Continue holding the FUNCT key and press Y3 Move the vertical crosshair to the middle of the peak 2 1 12 Continue holding the FUNCT key and press R2 Move the horizontal crosshair to the apex of the peak 2 1 13 Release the FUNCT and the R2 keys 2 1 14 Press R1 to zoom in on the image and use FUNCT R2 and FUNC
32. The torch unit is mounted in a torch box whose position relative to the entrance slit of the polychromator can be adjusted with a universal stage As with the plasma source torch position and optimal signal collection are under manual control EA18 1 Traces ICP OES TABLE ICP1 ANALYTICAL WAVELENGTHS AND CHANNELS ON JY48P ICP OES SYSTEM Fixed Channel Elements Wavelengths A CH Element Wavelength A Order 1 Tin 1899 26 1 2 Molybdenum 2020 30 1 3 Tungsten 2079 11 1 4 Boron 2089 59 1 5 Zinc 2138 56 1 6 Phosphorous 2149 14 1 7 Lead 2169 99 1 8 Gadolinium 3422 46 1 9 Cobalt 2286 16 I 10 Nickel 2316 04 1 11 Barium 2335 27 1 12 Tantalum 2400 63 1 13 Scandium 2552 37 1 14 Manganese 2576 10 1 15 Chromium 2677 16 1 16 Iron 2739 55 1 17 Magnesium 2798 06 1 19 Vanadium 2924 02 1 20 Aluminum 3082 15 1 21 Niobium 3094 18 1 22 Beryllium 3130 42 1 23 Calcium 3158 57 1 24 Copper 3247 54 1 25 Silver 3280 68 1 26 Ytterbium 3289 37 1 27 Titanium 3372 80 1 28 Zirconium 3438 23 1 29 Dysprosium 3531 70 1 30 Samarium 3592 60 1 31 Yttrium 3710 30 1 32 Lanthanum 3794 78 1 33 Europium 3819 67 1 34 Neodymium 4061 09 1 35 Strontium 4077 71 1 36 Cerium 4137 65 1 5 The instrument is equipped with Digital 11 23 computer with 128 Kbytes of memory dual RXO2 floppy disk drives DECWRITER III LA120 and Tektronix 4006 1 video terminals The software provided by the Instruments S A Metuchen N J p
33. Transfer the sample to the 40 mm die to which an aluminum former sleeve has been added Pack the contents with a plexiglass plunger to form a compact puck Remove the sleeve and plunger and add the boric acid powder placing it on top of the sample A measuring vial in the boric acid container indicates the amount to be added Complete the assembly of the die and form the pellet by application of 15 tons pressure for 15 seconds using pellet press Removed the pellet from the die and label it with a felt tipped marker on the boric acid side EA6 10 1 3 8 Leave the pelletface downon a cellulose wipe for 24 hours to allow the binder to dry A well made pellet should have no cracks an even surface and the rock powder should be centered within the outer ring of boric acid approximately 2 mm If a pellet is considered unsuitable a new one is made from a fresh subsample of rock pulp It is important to keep the die clean Boric acid and rock powder can build up on the surfaces and con taminate subsequent samples A thorough cleaning with a cellulose wipe after each pellet is removed will generally suffice Methanol should be used on the wipe to give a more thorough cleaning The surface in contact with the rock powder must then be treated with care It can become pitted and must be polished by gently rubbing the surface with a fine abrasive moistened with methanol Application and release of pressure on the die press s
34. analysis 2 12 Samples are analyzed using the steps indicated above 3 Calculation Multiply the carbon reading by 3 66 to convert it to equivalent 4 Analysis of Samples with High C or S Con centrations Samples containing gt 2 7 C or 20 896 S are analyzed in a similar fashion less weight 0 1 g or less of sample is used the AWC control is not employed and the weights are manually recorded Results are ob tained by dividing the observed results by the sample weight S Instrument Shutdown 5 1 Atthe end of the analysis remove any remain ing crucible from the furnace 5 2 Tum the O gas supply off and allow any oxygen remaining in the lines to escape 5 3 Tum the HIGH VOLTAGE and FILAMENT VOLTAGE off 5 4 Set the PUMP and GAS switches to the off position down 5 5 Leave the Determinator and Furnace in this mode for best instrument stability If the sys tem is expected to be off for an extended period the POWER switch may be tumed off 6 Routine Maintenance 6 1 A system electronics check as described in the Leco manual page 17 should be performed daily 6 2 A leak check as described in the Leco manual page 16 should be performed weekly 6 3 Linear Card Adjustment Leco Bulletin 1 2 3 4 is carried out for C CO or S if erratic readings are obtained during standardization or standardization checks Typically this hap pens after two to four weeks of operation 6 4 Th
35. cursor gt The structure of RSX 11M is too complex to discuss in this manual It should be understood however that operating system programs are generally stored in sub units called directories and are accessed by log ging on The logging instruction requires both a software name and a password For the PW1400 the instruction required is LOG x14 x14 2 3 Enter LOG x14 x14 and push retum The in strument will respond with RSX 11M BL35B 1 54 System RSX11M dd mmm yy hr mn Logged on Terminal TTO TTO LA100 Good morning gt LOGIN CMD gt gt To run the X14 task type MCR X14 or X14 To run the Regression task type MCR REG or REG gt gt lt gt The new cursor indicates that the system is in the correct directory Various RSX 11M commands are available to initialize disks locate directories etc 2 4 Activate the system by typing X14 or MCR X14 The system will respond with a message in dicating ownership of software etc and ends with the system cursor NOTE The PW1400 software operates in two modes automatic mode cursor and manual mode cursor C In the automatic mode the operator can communicate with both the microprocessor which controls the instrument and with the computer which stores the information In manual mode the operator can communicate only with the microprocessor In order to establish the proper communications b
36. for example one examines the physical chemical steps that occur in taking the analyte from the sample tube to the detection of radiation in an ICP experiment it is possible to identify many sources of potential non spectral interference 1 Transport of sample to nebulizer Whetherone relies on the natural uptake rate of the solution or the use of a peristaltic pump the vis cosity of the sample will have a bearing on the rate of analyte delivery to the plasma Reduction in flow will generally result in signal depression 2 Nebulization of sample The rate of aerosol formation in the nebulizer will depend on the total salt content in the sample solution Reduction of sample flow for high salt samples or nebulizer blockage due to precipitation will probably result in signal depression 3 Aerosol in the spray chamber The design of the spray chamber the temperature of the spray chamber and the nature of the sample will determine the droplet size distribution in the aerosol This in turn will determine the amount of sample which can be swept into the plasma 4 Processes in the Plasma Vaporization of solvent Vaporization of sample saits Atomization of sample components Ionization of sample atoms Recombination of atoms to form transient species Excitation of atomic species Excitation of ionic species Excitation of molecular species Oxide formation The efficiency of these processes w
37. reporting time Additional Notes 1 The T5 package requires three separate solution with the T5 elements separated as follows Traces ICP MS a Hf Ta Sr Zr Nb Rb Cs b Pb Th TI c Sn The 80 ppb working solution is prepared by serial dilution of the 1000 ppm stock solutions The Ru Re calibration scheme is used for Rb Cs Nb Sr Zr Hf and Ta All others use the external calibration procedure Thus separate runs on the Elan 250 are required to accomplish a full T5 analysis Sn fusion solutions received from the Chemistry Subsection are further diluted by a factor of 5 for a final dilution factor of 2500 EA19 19 Traces NAA DETERMINATION OF THE RARE EARTH ELEMENTS La Ce Nd Sm Eu Yb Lu THORIUM TANTALUM HAFNIUM URANIUM AND SCANDIUM BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS Introduction Instrumental neutron activation analysis INAA provides non destructive determination of the REE Th Ta Hf U and Sc These elements are extremely useful as tracers in a wide variety of geological proces ses refer to Volume I Chapter 16 An advantage with this method is that it does not involve dissolution A disadvantage is that it does not allow for the determination of all rare earth elements Safety advisory 1 Sample containers should be air tight and handled with extreme caution to avoid the leakage of radioactive rock dust after the samples are removed from the reactor and att
38. sample is crushed 7 The crushed sample is split in the vented riffler 8 Reject material is retained in a pulp bag 9 About 100 g of crushed rock is placed in a cleaned chrome steel mill The mill is secured to the vibratory ring pulverizer and ground for an ap propriate length of time depending on hardness Typically 90 seconds is sufficient 10 The mill is transferred to the blow out area and the rock powder is collected on glazed paper and transfered to a previously labelled pulp bag General comment Use two chrome steel mills so that one is grinding while the other is being cleaned with compressed air Assay Preparation uality Control When the mill cannot be cleaned with compressed air quartzite is used Assay grinding is used in the preparation of samples for geologists and prospectors who do not require whole rock geochemical analysis A record is kept of the sequence in which the samples are ground and of the identity number of the container used for each sample This record is of use if a high grade sample is identified in the analytical stage it allows contamination of subsequent samples to be checked Productivity Typically a technician can complete forty five assay grinds per day One hundred assay grinds are possible under ideal sample conditions MS1 3 Wwnoie rock reparation WHOLE ROCK SAMPLE PREPARATION Introduction This preparation technique is applied whenever the geol
39. should be accompanied by cheque or money order payable to the Treasurer of Ontario Reports maps and price lists personal shopping or mail order Public information Centre Ministry of Natural Resources Room 1640 Whitney Block Queen s Park Toronto Ontario M7A 1W3 _ 416 965 1348 Collect calls accepted Reports and accompanying maps only personal shopping Publications Ontario L Main Floor 880 Bay Street Toronto Ontario M7A 1N8 Canadian Cataloguing in Publication Data Main entry under title The Analysis of geological materials an Ontano Geological Survey miscellaneous paper ISSN 0704 2572 149 Contents Vol I A practical guide A Vander Voet and C Riddle v II A manual of methods staff of the Geoscience Laboratories ISBN 0 7729 7034 3 2 v set ISBN 0 7729 7035 1 v I ISBN 0 7729 7036 X v IT 1 Rocks Analysis Laboratory manuals I Vander Voet A H M 1945 II Riddle C Ontario Mines and Mmerals Division IV Ontario Geological Survey V Series QE433 A52 1990 552 06 C90 092526 4 od Every possible effort is made to ensure the accuracy of the information contained in this report but the Ministry of Northern Development and Mines does not assume any liability for errors that may occur Source references are included in the report and us ers may wish to verify critical information If you wish to reproduce any of the text tables or illustrations in this report please wr
40. signal by the Coulometrics CO Determinator 3 Calculation of the results based on weight Apparatus Coulometrics CO Determinator which consists of A Model 5010 Coulometrics CO Coulometer B Model 5030 Carbonate Carbon Apparatus with reaction tubes Reagents Perchloric acid 2N Potassium hydroxide solution KOH 45 Potassium Iodide solution KI 5096 KI solution at pH 3 Coulometer solution Anode solution Potassium iodide crystals KI Procedures 1 Measurement of carbonate carbon concentra tion 11 Coulometer set up Place approximately 100 ml of coulometer solution in the cell body See Figure CC1 Add stirring bar Place a few crystals of KI inside the anode compartment Place the cell cap on the cell body and add anode solution to the anode compartment so that when the silver electrode is in place the anode solution level will be the same as the solution level in the cell body EA28 1 Carbonate Carbon 1 1 5 Placethecellinthe coulometer cell holder with the electrodes to the back Be sure the cell current switch is off and tum on coulometer The anode compartment frit and gas inlet tube should be positioned so that they are in the back of the light beam This may be checked by rotating the cell until maximum T is ob served The Pt electrode should project out and away from the light beam for highest sen sitivity 1 1 8 Plug in the
41. some MnO will be produced in addition to the Mn Evidence of this is faint brown dis coloration of the solution If this occurs the titra tion should be stopped until the solution becomes clear The solution must be free of MnO at the equivalent point Platinum vanadium copper arsenic antimony and molybdenum interfere in KMnO titration in stannous chloride reduction Platinum is usually introduced through operations carried out in platinum vessels Bibliography Hillebrand W F and Lundell G E F Applied Inor ganic Analysis Second Edition 1929 Jeffrey P G and Hutchinson D Chemical Methods of Rock Analysis Third Edition 1981 pp 192 Total Fe Potts P J A Handbook of Silicate Rock Analysis Blackie and Sons Ltd Glasglow 1987 622 pages Maxwell J A Rock and Mineral Analysis Wiley Interscience Publishers 1968 pp 421 Skoog D A and West D M Fundamentals of Analytical Chemistry 1963 pp 435 443 EA14 5 Ferrous DETERMINATION OF FERROUS IRON TITRIMETIC METHOD Introduction Iron is an important industrial commodity Iron bear ing sedimentary rocks furnish the bulk of industrial iron ore The main ferruginous groups are carbonates silicates oxides and sulphides In additionto its commercial importance chemical and mineralogical data relating to iron are used in studies researching the origins of rock deposition and metamorphism More information about iron is
42. to the first faint pink end point that persists for 15 seconds 2 3 4 2 3 5 2 3 6 Do not titrate rapidly at any time Two blanks should be carried through the procedure Correct the volume of KMnO for the blank titration The standardization should be carried out in triplicate and the average titer taken for the normality Calculate the number of milligrams Fe and Fe 0 equivalent to 1 ml of KMnO 3 Sample decomposition 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 3 10 3 12 3 13 Weigh exactly 0 200 g of sample and transfer to a 50 ml teflon beaker Moisten with distilled water Cover the beaker and add 10 ml of conc When effervescence has ceased heat on a hot plate for a few minutes Remove and rinse off the cover into a beaker Add 5 ml of HF 48 Evaporate to dryness Add 5 ml of concentrated and leave it for lor2 minutes Add 25 ml of distilled water Heat well and ensure that the sample is com pletely dissolved If any black gritty particles are noticed the solution should be filtered using Whatman No 40 filter paper into a 250 ml beaker Wash a few times with small portions of hot distilled water The paper with undissolved particles should be ignited in a Vycor glass crucible 30 ml Fuse the ignited residue a with small amount of potassium pyrosulphate K S 0 Dissolve the fused matter in the crucible in distilled wate
43. tranfer to a 100 ml volumetric flask and develop the colour as per procedure 5 A number of other metals form coloured com plexes with hydrogen peroxide including vanadium uranium niobium molybdenum and under certain circumstances chromium 6 Presence of alkali salts causes slight bleaching effect the bleaching action of alkali salts is less in a 10 by volume solution of H SO than in one containing 5 7 Intitanium solutions a moderate amount 10 20 of acid must be present to prevent precipitation of titanium by hydrolysis Bibliography Hillebrand W F and Lundell G E F Applied Inor ganic Analysis Second edition 1929 1034 pages Jeffery P G Chemical Methods of Rock Analysis 3rd Edition 1981 379 pages Maxwell J A Rock and Mineral Analysis Wiley Interscience Publishers 1968 584 pages Potts P J A Handbook of Silicate Rock Analysis Blackie and Sons Ltd Glasglow 1987 622 pages Phosphorus DETERMINATION OF PHOSPHORUS P203 COLORIMETRIC METHOD Introduction The determination of phosphorus usually present in the range 0 1 0 5 is a necessary part of any silicate rock analysis In silicate rocks and minerals the phosphorus is usually present as orthophosphate apatite is the most common mineral Phosphorus is also an essential constituent of living matter The average natural crustal abun dance of phosphorus in igneous rock is approximately 1200 ppm Limeston
44. tualistic melilite i e showing the replacement of Ca by Na and Al by is not calculated because the geochemistry of melilite is not clear The formation of the iron bearing akermanite by desilicating diopside in IV J of the calculation is govemed by the relation 4 Ca Mg Fe Si 0 3510 2Ca Mg Fe SiO Mg Fe 2SiO Calcium orthosilicate is not calculated since it is quite unrealistic Washington 1915 3 The significance of the roles of Ca and Fe as well as the alkalis is demonstrated In particular in stead of using all the ferric iron early in the cal culation to form acmite and magnetite as in the CIPW system here some is retained till later to enable the possible formation of andradite 4 Itallows more realistic comparison with the mode and facilitates geochemical and mineralogical in terpretation However amphibole and micas are not calculated nor is ilmenite because it is not normally a common constituent in strongly alkaline and oxidized magmatic rocks Algorithm 1 Determine the molecular proportions of the con stituents in the chemical analysis by dividing the weight percentage of each by the molecular weight Add MnO to FeO and SrO and BaO to CaO 2 If molecular SiO gt FeO MgO CaO 6 Na 0 K 0O then omit stages 3ei 3eii 3eiii 4A 4B 4C 4E and 4K 3 Allot molecular amounts in the order and in the ratios listed below CaO 3 10 for apatite b CaO
45. 001 for interference of Fe on Mo and V However use of both 100 and 1000 ppm Fe indicates that the effect of Fe on V is more background whereas the effect on Mo is a true interference because the signal at Mo is proportional to the Fe concentration In the absence of sequential or mutual interferences software or manual correction is straight forward The appropriate analyte and concentration data are obtained from the calibration curves and the interferent contribution calculated and subtracted from the ob served analyte concentration to give the actual analyte value In the case of sequential interferences the correction is more complex For example consider a case where analyte A interferes on B coefficient x1 and B inter feres on C coefficient x2 Therefore CA obs CA true CB obs CB true x1 CA true CB tme x1 CA obs CC obs CC true x2 CB true and CC obs CC true x2 CB obs x1 CA obs CC true CC obs 2 CB obs x1 x2 CA obs Traces ICP OES Depending on the value of CA and the magnitudes of 1 and x2 the final term in the correction may be significant and should be included Some software packages e g that of the JY48P do correct in se quence and rely on the order of entry of the correction coefficients elements Others use the original ob served concentrations only Sequential interference corrections may need to be corrected off line Mutual interferences are illus
46. 1 The sensor must be cleaned with alcohol micro solution and water before operation Between samples the sensor should be cleaned with distilled water 5 2 The concentration limit of the sensor is de pendent on the grain size of the sample Very dilute solutions must be used This can be achieved by taking 1 ml ofthe sample solution 250 ml containing up to 2 g of sample and making up to one liter 5 3 Analyses should be conducted in duplicate 6 Particle size distribution data from the sensors Data are stored at the end of each run in a job file two files are maintained for each job one for each sensor Once both wet and dry runs are completed the ASCII translation option is invoked to create ASCII files from the PDAS data sets this is done sequentially for each sample and standard The ASCII files are saved on floppy disk and the original PDAS data file is deleted from the system 7 Analysis of the clay fraction by hydrometry A sample of soil passing No 10 sieve weighing 50 g for clay rich soils or 100 g for sandy soils is allowed to soak overnight in a solution of the dispersant 125 ml The soil and water are then transferred into a mixer for 1 minute and washed into a graduated cylinder The cylinder is filled to the 100 ml mark with distilled water The covered cylinder is inverted repeatedly for 1 minute before commencing the read ings and readings are then taken after 1 hr 2 hrs 3 hrs and 4 hrs The
47. 1 4 1 5 1 6 6 ammonium oxalate solution NH4 C 0 H 0 Heat solution to dissolve filter and make solution to volume with dis tilled water 20 Diammonium phosphate solution Dissolve in distilled water fil ter and make to volume with distilled water 2 Ammonium nitrate solution Dissolve in distilled water neutralize with ammonium hydroxide using a methyl red as an indicator and filter 0 1 Ammonium oxalate solution Dissolve in distilled water if necessary by heating and filter 5 0 Ammonium hydroxide solution v v in distilled water 5 Hydrochloric acid solution v v in distilled water NOTE Make solutions in quantities sufficient for the number of samples to be analyzed 2 Fusion and sample decomposition 2 1 Weigh exactly 0 800 g of sample in a clean 25 ml platinum crucible Weigh 4 g on top load ing balance of Na CO flux Mix with a small teflon rod NOTE If sample is very high in sulphides or ferrous 2 2 iron a gentle preliminary roasting in the crucible of the weighed unmixed sample at a dull red heat for several minutes is desirable to prevent any subsequent reduction of FeO to metallic iron which then alloys with the pla num By fusing with a basic flux the minerals of the rock are changed into com pounds which are soluble in HCI Retum the covered crucible to the triangle sup port and heat the crucible with a low flame for approximately 5
48. 1 75 50 40 40 33 900 80 Rh Ka NO F S 1 1 75 25 50 40 18 300 Nb Ka NO F S 1 1 80 15 50 40 21 345 50 Ga Ka NO F S 1 1 75 25 50 40 38 845 46 Ta LB NO 1 1 75 25 50 40 38 465 30 Ce Lp NO F F 1 1 70 30 65 30 71 600 70 Nd La NO E F 1 1 60 25 65 30 72 125 1 80 La La NO F F 1 1 70 25 65 30 82 865 1 00 Cs La NO F F 1 1 80 15 65 30 91 865 2 00 4 Manual Operation POS 1 ABC 1234 enter sample numbers 4 1 Tostore concentration information on the hard disk enter WDD XXXXXX Write Datato POS 4 2 ABC 1235 Disk filename XXXXXX SA dO Ga Ge diae etc 4 2 If you wish to print intensity data to the printer as the analysis proceeds enter PIN Print Intensities 5 Use of Sample Changer 4 3 Place the samples in sampling cups The 72 position sample changer is used to expand the capabilities of the PW 1400 as an unattended instru 4 4 Start the measuring program by entering ment Samples are loaded in the sample trays SMX Start Measurement Program The pro 6 samples tray and trays are placed in the sample gram will respond with POSITIONS changer Identification cards are inserted into the ap propriate slots of the trays These cards indicate the 4 5 Respond with 12341 Useallfourturrets tray number and the program MP LP number As the wait for sample i d The system willbringthe card is read by the optical reader on the sample first position 1 into the loading position changer the correct measurement sequence will be ope
49. 10 144 620 Optimization of channel parameters Angle Calibration Once a channel has been defined parameters can be optimized A sample containing a high concentration of the analyte is used for this purpose There are four sample positions in the changer 1 2 3 amp 4 of which two are of interest the LOADING and the MEASURING To load a sample into a specific location the instrument sample holder must first be brought into the loading position Enter SLP 1 Sample Loading Position 1 This will bring sample location 1 into the loading position Place a sample cup containing an appropriate sample into the sample chamber Bring sample location 1 into the measuring position by entering SMP 1 To optimize the ANGLE the instrument is first set at the appropriate channel e g Fe Set the spectrometer to the appropriate channel by entering SCH FE Set channel This will set the correct conditions for Fe measurement To calibrate the peak position the system will perform a short scan around the 2 theta angle listed in the PB The instrument will determine the true peak position Enter CAN FE Calibrate ANgle Fe The system will respond with TIME 1 0 count time per point default 1 s Enter R to select the default RANGE 0 2 0 1 degree around the 2 theta entered in 0 005 steps The system performs the scan finds the new peak and reports both the original and the new peak positions The message ends
50. 1203 CaO amp MgO CLASSICAL GRAVIMETRIC METHOD Introduction For an introduction about the abundance and occur rence of the major elements refer to Determination of Major Elements by Flame Atomic Absorption Spectometry page EA7 1 of this manual Although largely superceded by more productive in strumental methods classical methods for the deter mination of major elements have generally not been surpassed in terms of the quality of data produced The Geoscience Laboratories participates in projects with national and international laboratories and uses these methods for certification purposes These method are also used where the sample matrix makes the constituent concerned unsuitable to be determined by XRF This will arise when the sulphur content of the rock is too high to allow a fused bead to be prepared by XRF Safety advisory 1 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17 2 Other acids are used throughout this method and all staff must review the appropriate MSDS sheets Apparatus Platinum crucibles 25 ml with covers Glazed porcelain casseroles 250 ml Watch glasses 12 cm supported by glass tri angles Glass rods Platinum tipped tongs Glass beakers 250 ml 400 ml 600 m1 800 ml and 1000 ml Glass funnel 75 mm Filter papers 12 5 cm Whatman No 40
51. 134 0 138 2 61 9 67 6 20 7 73 9 77 9 81 2 85 5 90 1 96 0 Traces XRF EA16 19 Traces XRF APPENDIX E XRF DETECTION LIMIT CALCULATION CHR 4 PRINT TURN ON PRINTER D PR42 PRINT DETECTION LIMIT COUNTS XRF PRINT ELEMENT NAME ELS BACKGROUND COUNTS B PEAK COUNTS P B gt N CONCENTRATION OF ELEMENT C 70 P B C 10 D 15 PRINT 20 PRINT 30 PRINT 35 PRINT 36 INPUT 40 INPUT 50 INPUT 55 N P 60 PRINT 65 INPUT 80 PRINT 85 INPUT 90 PRINT 91 DL 92 DL 100 PRINT 110 PRINT 120 PRINT 130 INPUT 140 IF R 149 PRINT 150 END EA16 20 CONCENTRATION FACTOR M COUNT TIME AT BKG TB PRINT 3 M SQR B TB INT DL 100 100 D L 3 M SQRT B TB DL PRINT PRINT MORE Y N R Y THEN 35 D PR40 Traces XRF APPENDIX F RATE CORRECTION PARAMETERS Trace element determinations are divided into several groups or packages and divided within the software into several measurement programs Measurement programs under file OTHER use a common rate correction file RC which is listed below NR BKGR CHL2 I2 CHL3 13 CHL4 14 1 0 Y 1 3021 0 0000 0 0000 0 0000 2 0 Y 1 0855 Rb 2600 0 0000 0 0000 3 0 Y 9090 0 0000 0 0000 0 0000 4 0 Y 8262 0 0000 0 0000 0 0000 5 0 Y 7967 U 1400 0 0000 0 0000 6 0 Th 1 2203 0 0000 0 0000 0 0000 7 0 Pb 1 1717 0 0000 0 0000 0 0000 8 0 Y 1 5614 0 0000 0 0000 0 0000 9 0 Ta 92
52. 2 Additional Notes 1 Samples are analyzed simultaneously in a batch of 12 or more depending on the availability of work _ ing space 2 The method does not determine organic insoluble residues as these would be destroyed in the com bustion stage Bibliography Maxwell J A Rock and Mineral Analysis Wiley Interscience Publishers 1968 pp 304 305 and pp 487 488 Potts P J A Handbook of Silicate Rock Analysis Blackie and Sons Limited Glasglow 1987 622 pages Chittick DETERMINATION OF THE CALCITE TO DOLOMITE RATIO CHITTICK APPARATUS METHOD Introduction The determination of the carbonate content and cal cite dolomite ratio of sedimentary rocks and tills provides valuable information enabling the geologist to classify the materials and determine their suitability as materials for use in the construction industry The concentrations of these minerals are highly variable in rocks and tills The method is based on the different reaction rates of calcite and dolomite in hydrochloric acid The ratio of calcite to dolomite in a finely ground sample minus 200 mesh can be determined by taking two readings of the volume of evolved CO in a Chittick gasometric apparatus The first reading records gas evolved prin cipally from the faster reacting calcite the second reading records the gas evolved from both minerals Safety advisory 1 This method involves the specific use of hydrochloric acid Staff must
53. 2 The sample tray and the waste bottles which col lect the acidic drains from the hydride generator should be covered to prevent the acid vapour from escaping to the ambient air Good ventilation in the working area is essential Method The method consists of the following techniques 1 Fusion and sample decomposition A Arsenic fusion with sodium hydroxide and dissolution by hydrochloric acid B Antimony decomposition by sulphuric and hydrofluoric acid C Bismuth decomposition by perchloric and hydrofluoric acid 2 The elements are converted to hydride form by sodium borohydride 3 Measurement by atomic absorption spectrometry 4 Calculation of As Sb and Bi concentrations based on a calibration curve produced from known standard solutions Apparatus Varian Model AA 6 atomic absorption spectrophotometer equipped with a model 9176 1 100 MV recorder Technicon sampler II Technicon proportioning pump I Gas liquid separator Gasimpinger Quartz tube 16 cm long 10mm i d with an inlet tube fused into the centre wound with a 22 gauge chromel A heating wire and insulated with a layer of wrapped Thermofab string Staco variable transformer Hot plate Nickel crucibles 40 ml Stoppered graduated cylinder 50 ml Glass beakers 100 ml Teflon beakers 30 ml Testtubes borosilicate 18 X 150 mm graduated at 15 ml Test tubes polystyrene 16 X 150 mm A25 1 As Sb Bi Reag
54. 200 ml of distilled water add 125 of concentrated hydrochloric acid Cool and make to volume with distilled water 1 3 Matrix acid mixture To a 1000 ml volumetric flask containing approximately 500 ml of dis tilled water add 62 5 ml of concentrated nitric acid and 62 5 ml of concentrated hydrochloric acid Cool and make to volume with distilled water 2 Standard Au Pt and Pd solution preparation 2 1 100 ppm Au solution Pipet 20 ml of 1000 ppm Au into a 200 ml volumetric flask and make to volume with 0 5 22 10 ppm Au solution Pipet 20 ml of 100 ppm Au into a 200 ml volumetric flask and make to volume with 0 5 N 2 3 100 ppm Pt solution Pipet 20 ml of 1000 ppm Pt into a 200 ml volumetric flask and make to volume with matrix acid mixture 24 10 ppm Pt solution Pipet 20 ml of 100 ppm Pt into a 200 ml volumetric flask and make to volume with matrix acid mixture 2 5 100 ppm Pd solution Pipet 20 ml of 1000 ppm Pd into a 200 ml volumetric flask and make to volume with matrix acid mixture 2 6 10 ppm Pd solution Pipet 20 ml of 100 ppm Pd into a 200 ml volumetric flask and make to volume with matrix acid mixture 2 7 Working standard solutions Prepare 0 5 0 10 0 20 and 0 30 ppm Au Pt and Pd solu tions by adding 0 5 1 0 2 0 and 3 0 ml of 10 ppm Au Pt or Pd solution with a 10 ml EA21 2 microburette to 100 mi volumetric flasks Make to volume with the matrix acid mixture
55. 3 Inthe presence of HF ferrous iron may oxidize to ferric iron The boric acid removes fluoride ions forming BF The sequestering of fluoride ions prevents oxidation of the iron The boric acid also aids in obtaining a lasting end point 4 Pyrites are not dissolved by this procedure Bibliography Goldich S S 1984 Determination of Ferrous Iron in Silicate Rocks Chem Geol 42 pp 343 347 Fitton J G and Gill R C O 1970 The Oxidation of Ferrous Iron in Rocks During Mechanical Grinding Geochim Cosmochim Acta 34 518 524 Langmhyr F J and Graff P R 1965 A Contribution to the Analytical Chemistry of Silicate Rocks A Scheme of Analysis for Eleven Main Constituents Based on Decomposition by Hydrofluoric Acid Nor ges Geologiske Undersokelse No 230 Univer sitetsforlaget Oslo Langmhyr F J and Kringstad K 1966 An Investiga tion of the Composition of the Precipitates Formed by the Decomposition of Silicate Rocks in 3895 4096 Hydrofluoric Acid Anal Chim Acta 35 131 135 Ferrous Potts P Handbook of Silicate Rock Analysis Blackie Glasglow 1987 622 pages Wilson A D 1955 Determination of Ferrous Iron in Rocks and Minerals Bull Geol Survey Great Britain 9 56 58 EA15 5 Traces XRF DETERMINATION OF TRACE ELEMENTS T3 X RAY FLUORESCENCE SPECTROSCOPY Introduction The Philips PW 1400 XRF spectrometer system is used for the quantitative determination of the trace elements
56. 5 12 6 12 8 GA 12 1 8 50 9 58 Mica Mg 13 4 13 3 13 1 In all cases the Compton computed value in the previous table MA C is closest to the MA from the major element composition MA Major This indicates the validity for using the Compton line in the calculation of the corrected counts for calibration NIM L is not a typical rock sample because it contains percent level Zr and very high Sr an interferent The above calibration is carried out over a high range of concentrations If a smaller range is used 1 NIM L included the agreements are indicated in Calc Thus the NIM L Zr determination is over corrected for the extremely high level of Sr found in this sample 4600 ppm This example shows that the standards used in a calibration are often not representative of normal silicate rocks In unusual cases attention should be paid to the overall composition of the sample especially unusually high levels of trace elements XRF scans are often used to detect the latter The agreement between expected and calculated values for other Trace 3 elements is generally good EA16 6 Traces XRF Measurement Program for the Determination of Gallium Gallium is determined as a separate measurement program MP3 stored in DB PB OTHER Channel conditions are highlighted below Rh Ka NOF S 1 1 75 25 50 40 18 300 Ga Ka NO F S 1 1 75 25 50 40 38 845 46 Ta LB NO FS 1 1 75 25 50 40 38 465 30 Tantalum Ta Lf line at 2 theta 38 450 is not ex
57. 7 Eu 0 005 1 0 15 30 Sr 0 01 150 Ce 04 40 These elements are routinely determined at less than optimum sensitivity due to their high natural abundances Lower determination limits may be possible if requested Traces ICP OES TENTATIVE SPECTROSCOPIC ANALYIS PACKAGE TSPA INDUCTIVELY COUPLED PLASMA OPTICAL EMISSION SPECTROSCOPY Introduction Apparatus A general introduction to the principles of ICP optical Refer to the Trace 2 Package emission spectroscopy is given in Overview to Trace Element Determination by ICP Optical Emission Reagents Spectroscopy An explanation of potential interferen ces and procedures for dealing with these is given Refer to the Trace 2 Package The Tentative SPectroscopic Analysis TSPA pack Procedures age provides semiquantitative analysis of 26 elements including Al Be Ca Ce Cr Co Cu Fe La Pb Refer to the Trace 2 Package Mg Mn Mo Ni Nb Nd P Sr Ta Ti W V Y Zn and Zr Results are reported in terms of percentage Quality Control concentration ranges Refer to the Trace 2 Package Safety advisory Productivity Refer to the Trace 2 Package Refer to the Trace 2 Package Method Additional Notes Refer to the Trace 2 Package Refer to the Trace 2 Package EA18 25 Traces ICP OES APPENDIX A GENERATION OF THE TSPA CERTIFICATES Introduction A series of programs have been written to allow a user to generate signature ready TSPA cert
58. BS AND C THEN 1080 1070 GOTO 1090 1080 PRINT NAS I GS M1 I GS G 1090 IF A AND BS Y AND C THEN 1110 1100 GOTO 1120 1110 PRINT NAS I G G M2 I G 1120 IF A AND BS AND C Y THEN 1140 1130 GOTO 1150 1140 PRINT NAS I G G G M3 I EA16 16 1150 1155 1160 1170 1500 NEXT I PRINT FF PRINT CHRS 27 Q PRINT D PR40 END Traces XRF EA16 17 Traces XRF APPENDIX C MASS ABSORBANCE VALUES FOR SELECTED SILICATE S R MS SRM MA Sr Ko SR MMA Sr Ko MRB 7 14 5 SY 2 12 0 MRB 8 8 7 SY 3 12 6 MRB 9 9 0 MRG 1 17 5 MRB 10 9 5 MRB 11 10 9 GA 9 5 GH 8 7 NIM G 9 0 VSN 12 7 NIM D 13 8 UBN 9 9 NIM L 13 2 Mica Fe 19 4 NIM S 10 7 DTN 7 5 NIM P 13 5 DRN 12 7 NIM N 12 8 FKN 9 5 Mica Mg 12 8 G 2 9 5 GSN 10 0 W 1 13 8 BXN16 2 GSP 1 10 4 BR 15 3 BCR 1 14 5 SGR 1 8 2 QUARTZ 74 SDC 1 11 1 RGM 1 9 1 ANG 11 3 STM 1 10 3 MAN 7 8 BHVO 1 14 5 BEN 8 2 SCO 1 10 1 MAG 1 11 3 QLO 1 10 4 G 1 8 8 EA16 18 APPENDIX D MA FACTORS SR K WAVELENGTH Ga 104 8 Ge 113 5 As 122 8 Se 1327 Br 143 6 KR 21 8 23 6 25 4 274 29 5 31 7 33 8 36 3 38 8 41 4 44 0 47 0 49 6 52 7 55 6 58 9 61 9 65 7 68 8 72 4 76 3 80 2 84 2 88 0 92 7 97 3 100 8 105 5 110 4 115 1 120 0 124 3 129 7 135 7 140 5 Reference Henrich s Tables 145 4 151 3 156 9 163 5 169 2 175 1 181 4 186 7 122 2 125 8 130 2
59. Ba Sc Cr Mg V Nb Ca Ag Ti Dy Y Eu Sr Gd Ni Ta Mn Fe Si Al Be Cu Yb Zr Sm La Nd and Ce Trace 2 T2 Rock pulps are prepared for analysis by acid digestion The elements available in the Trace 2 package are Be Sc Nb Mo V Sr Y Co Cu Ni and Zn Tungsten is also offered at relatively high determination limits Ce La and Nd are offered as options Zr normally determined by XRF is also available The acid resistance of most Zr containing minerals make ICP OES analysis of solutions un suitable for routine reporting of this element TSPA The Tentative Spectroscopic Analysis pack age on rock pulp solutions prepared by acid diges tion provides semiquantitative analysis of 26 elements including Al Ba Be Ca Ce Cr Co Cu Fe La Pb Mg Mn Mo Ni Nb Nd P Sr Ta Ti W V Y Zn and Zr Results are reported in terms of concentration ranges The operating concepts of inductively coupled plasma optical emission spectroscopy are as follows 1 A high temperature excitation source is produced by the interaction between a radio frequency field and a flow of argon gas The interaction results in the ionization and excitation of the Ar to produce a plasma or flame which can attain tempera tures in the range 8000 10000 C At these temperatures any sample which is introduced into the plasma will be vapourized atomized ionized and excited to emit radiation 2 The emitted light is
60. C and S are 0 001 and 0 00014 respectively under ideal conditions The determination limit for both CO and S is 0 01 Precision is estimated at 5 at the mid range value for both and S relative Productivity A technician should be able to complete 30 samples per day Additional Notes 1 The CS 46 system can be calibrated by standards otherthan reference rocks synthetic standards can also be prepared to cover the appropriate ranges Synthetic standards must be calibrated against ref erence rocks prior to their use as standards Bibliography Instruction Manual for CS 46 Carbon and Sulphur 748 600 System LECO Corporation 1977 Terashima S 1978 Anal Chim Acta 101 pp 25 Terashima S 1979 Geostandards Newsletter 3 pp 195 EA13 3 DETERMINATION OF TOTAL FE Total Fe VOLUMETRIC TITRIMETRIC METHOD Introduction Iron is the fourth most abundant element comprising about 5 percent of the earths crust Silicate minerals vary considerably in iron content and the variation is reflected in the iron content of silicate rocks Basic rocks may contain 30 to 40 percent iron calculated as Fe 03 while many acidic rocks contain as little as percent total iron Ferric iron is frequently as sociated with aluminum and ferrous iron with mag nesium The sulphide mineral pyrite FeS and associated minerals of composition FeSO 7H 0 in the oxidation zone surrounding pyrite are common Iron c
61. CHEMICAL CONCENTRATION input manually through ACD CALCULATED CONCENTRATION CONCENTRATION DIFFERENCE CHEMICAL APPARENT CONCENTRATION Equal to the value C 1 SUM aC from the DJ correction formula If alphas are used the chemical apparent concentration is equal to the chemical concentration CALCULATED APPARENT CONCENTRATION IDENTIFICATION The operator can introduce alpha corrections using the command CAL XX CAL calculate alpha where XX is the element influencing the result All alphas can be eliminated using command RCF reset Samples can be removed from the calibration list using command DSA and restored using ISA Plots can be observed on graphic terminal using command PLT Once the regression is deemed satisfactory the D E and alpha values can be stored at the appropriate Calculation Parameter CP Set The CP set is identified by number as listed in the LP set To place the regression parameters in the CP set the operator enters SRR 1 store regression results in CP 1 If CP1 is a new list the system responds with EA6 28 Majors XRF NEW LIST NAME can enter any name or title desired e g Major Elements NDEC 3 number of decimal places If the CP not new then only the number of decimal places desired is requested Ifthe same analyte and influencing elements is found in a different CP listing and if upgrading is also required the SRR instruction can be repeated directing the D E and
62. Classical quarters of the supernatant solution and filter the rest as previously described 6 2 9 Transfer the second precipitate to the same paper Wash beaker s precipitate and paper with cold 5 aqueous ammonia as before 6 2 10 Police the beaker s if necessary Wash the precipitate and paper ten times with aqueous ammonia solution and once with water Dis card the filtrate 6 3 Magnesium Ignition of magnesium am monium phosphate 6 3 1 Fold the paper lightly do not make a tight fold because this makes the burning away of the carbon more difficult and place it in weighed 25 ml platinum crucible 6 3 2 Wipe the inside of the funnel with a small piece of filter paper and add this to the crucible 6 3 3 Place the crucible with the cover drawn back slightly in a cold electric muffle furnace 6 3 4 Allow the temperature to rise to about 450 C and maintain it at this level until all of the carbon is burned off and the residue is greyish white in colour Do not allow the crucible to become even a dull red before this stage is reached and at no time allow the contents of the crucible to catch fire NOTE When MgNH PO is ignited it losses and NH and leaves a residue of magnesium pyrophosphate Mg P O Burning off the carbon at a low temperature is very important otherwise the platinum crucible if one is used may be injured and furthermore it will be impossible to get a residue free from carbon
63. Determination of the Calcite to Dolomite Ratio Chittick Apparatus Method vi Page Header Section Chloride oes lieb ves EA24 1 ASS SD BE whe tm os tirs dtu EA25 1 Selenium ill cw s ERE E EA26 1 MerCUry s AME E IS EA27 1 Carbonate Carbon e esses EA28 1 Moisture 0 ee EA29 1 ACID See ame ees EA30 1 Chittick mL Rub de RR EIS EA31 1 Sample Preparation THE TECHNIQUE OF SAMPLE PREPARATION The preparation of samples represents the single most important step in the analysis of geological materials Undetected errors in the handling of rocks such as sample mixup contamination with dust or rock frag ments and introduction of components from the grind ing equipment can lead to erroneous conclusions in the interpretation of the data The Laboratories uses two sample preparation proce dures on a routine basis 1 Preparation of samples for assay work and 2 Preparation of samples for whole rock geochemi cal analysis MS1 1 Assay ASSAY SAMPLE PREPARATION Introduction Assay preparation is employed whenever a geologist or prospector requires an indication of base or precious metal potential Assay samples are given high priority and a rapid turnaround The assay preparation should not be used when geologists require detailed geochemical work Safety advisory When working in the grinding area 1 Wear a full face piece respirator unit to eliminate the possibil
64. Dryinglamp Furnace to 1200 C Desiccators Ultrasonic bath 60 C oven Reagents Alcohol Ethylene glycol Hydrochloric acid 20 Hydrogen peroxide H20 Sodium hexametaphosphate Procedures 1 1 1 2 1 3 MS 10 2 Using a mortar and pestle crush a small piece 0 5g of the rock or if possible the individual minerals to a fine powder in alcohol which helps prevent loss of material due to fragments flying off The optimal size is about 10 microns and the powder should not feel gritty in the mortar Spread the slurry evenly over two thirds ofthe glass slide and let it dry under a heat lamp if necessary Ideally the sample should be one layer thick If only a small amount of sample is available a low background holder such as a specially cut quartz crystal or an iron plate should be used Some samples are received already crushed for chemical analysis If sufficient powder is available fill one of the special aluminum well mounts A glass slide is held against the front and the powder is poured in through the open ing at the side tapping the mount so that the powder is packed down This method is useful whenone wants to avoid preferred orientation 1 4 1 5 1 6 1 7 1 8 1 9 1 10 1 13 Check that the powder is sufficiently fine before packing it further grinding in the mor tar and pestle is usually necessary The powder mount is placed in the di
65. HCI 3 3 5 Transfer the contents with 1 4 HCI rinsing into a plastic test tube calibrated at 15 ml Make to volume with 1 4 Mix the solu tion thoroughly and allow the residue to settle 3 3 6 Prepare a reagent blank simultaneously 4 Measurement of As Sb and Bi concentrations 4 1 Setting up the hydride generator Set up the hydride generation equipment as depicted in Figure 1 using appropriate tube manifold Mount the quartz tube on a burner head with its inlet connected to a tygon tubing leading to the hydride generator 4 2 Tumon the power of the Varian AA 6 atomic absorption spectrophotometer Select the in strumental parameters according to the order given in the following table As Sb Bi As Sb Bi Wavelength nm 193 7 217 62232 Lamp Current mA 7 10 8 Slit Width u 300 100 50 Damping B C C Expansion 5 5 6 Recorder span mV 20 10 10 Recorder chart speed cm min 0 5 1 0 1 0 Variable transformer dial 40 40 40 Flowmeter reading 4 4 4 Sample time wash time 405 605 455 455 455 455 4 3 Load the sample solutions which are prepared on a batch basis in the sample cups and place them in order into the slots of a sample tray held on an automatic sampler After the hollow cathode lamp has warmed up align the quartz tube with the light beam to allow maximum radiation to reach the detector 44 Obtain the required temperature 850 C 20 C of the quartz tube atomizer by switching on the pre set v
66. IM 6 update Strip Recorder Varian Model 9176 or Linear Model 1200 Pipettes 5 10 20 25 50 ml Volumetric flasks 50 100 200 250 500 1000 2000 ml Acid dispensers Socorex Model 511 10 ml Various sized glass beakers Reagents Nitric acid 69 w w Stock Standard Solutions 1000 ppm A Custom Mixed Standard containing Co Cu Ni Pb Zn Mn Fe Ag B Chromium C Lithium D Barium E Cadmium Potassium Chloride KCl Lanthanum Oxide La O suitable for flame en hancement in atomic absorption spectrometry Method The method consists of the following techniques 1 Sample decomposition by either acid digestion or fusion with a flux Measurment of analyte signal by atomic absorp tion spectrometry Calculation of results based on calibration curves produced from synthetic samples Procedures 1 Reagent preparation 1 1 Lanthanum Potassium Reagent for Barium Determination 6000 ppm 6000 ppm Carefully add 200 ml of nitric acid to 14 07 g of lanthanum oxide placed in a 600 ml covered glass beaker CAUTION Reaction is vigorous and generates heat 1 2 Toa2liter volumetric flask add 22 89 g of KCl and dissolve with 200 ml of distilled water 1 3 Transfer the lanthanum solution when cool to the volumetric flask and dilute to 2 liters with distilled water 2 Preparation of Calibration Working Standards 2 1 Working standards are
67. INAA DURING A ROUTINE ANALYTICAL SCHEME Element Mean UTBI ppm Th 4 21 Ta 0 96 Hf 5 06 U 1 02 La 26 4 Ce 62 1 Nd 33 6 Sm 7 98 Eu 2 30 Yb 4 05 Lu 0 64 Sc 40 0 n d not determined Expected Value ppm 4 3 1 02 4 6 1 0 26 7 60 5 32 0 8 0 2 4 4 0 0 58 n d Mean WHIN SILL 2 15 1 6 4 92 0 45 24 7 60 4 28 4 7 02 2 04 2 5 0 35 30 4 o Epected Value ppm 0 26 3 1 0 9 1 26 0 48 4 9 0 14 0 90 0 5 22 5 3 8 57 5 5 2 32 9 0 26 7 3 0 10 2 3 10 14 2 54 0 02 0 39 0 8 n d EA20 3 Au Pt Pd DETERMINATION OF GOLD PLATINUM AND PALLADIUM GRAPHITE FURNACE ATOMIC ABSORPTION METHOD Introduction A renewed interest in the search for deposits of Au Pt and Pd has been stimulated by recent economic and political events This in tum has led to improvements in the methodologies by which laboratories determine the levels of these elements in geochemical samples It is well known that Au Pt and Pd are distributed in rocks in a heterogeneous manner occurring as discrete particles and minerals and existing in solid solutions in sulfides silicates and spinels Because of this so called nugget effect a minimum of 10 g of rock powder is used There has been a significant increase in the number of analytical techniques used to determine Au Pt and Pd in the past decade Of these techniques there is a general consensus that graphite fur
68. OES 1 13 1 14 1 15 ately switch the NEBULIZER gas flow on and increase the incident power to 1 8 kW Switch the reflected power switch at the RF generator to the right on If unsuccessful in igniting the plasma purge the system with argon for two to three minutes and repeat the procedures starting at step 1 8 If necessary adjust reflected power to a min imum with the fine knob located on the right end plate of the box BE PREPARED TO IMMEDIATELY PRESS RF OFF IN THE EVENT THE PLASMA EXTINGUISHES Let the system warm up for at least 45 minutes or until the inside chamber temperature remains fairly constant monitored by a ther mometer at the upper part of the front panel of the plasma box NOTE Refer to diagram 13 JY48P spectroanalyzer user s manual 2 JY48P Shutdown procedure 2 1 225 2 3 2 4 2 5 2 6 2 0 2 8 2 9 2 10 Dial the forward POWER slowly down to approximately 6 on the dial Press the RF OFF button on the front panel Depress the plasma and auxilliary gas flows off Dial the forward POWER down to 0 Flush the system by nebulizing deionized water for a few minutes Switch off the Nebulizer gas flow Let the RF generator to cool off for at least 15 minutes before switching the main supply off Turn off the peristaltic pump Disengage the clamps of the peristaltic pump and release the tubing Close the valve of the Argon gas supply EA1
69. PB include listing of channels and channel conditions listing of measurement programs i e channels monitored times used in counting listing of job programs i e sequence of spectrometer instructions NOTE These listings are all concerned with the physical settings of the instrument They en sure acquisition of data will be carried out in the correct manner To read what is in the PB type PPB Print Parameter Bank In order to use the X14 program for the analysis of samples a previously developed Databank must be LOADED into memory Following this the associated Parameter bank must be READ into memory All trace element instrument parameters are found in Parameter Databank files labeled OTHER Channel conditions for trace elements of interest stored in OTHER are listed in the table on the fol lowing page 3 1 Load the required databank enter LDB XXXXXX LDB Load Databank 3 Read the associated Parameter bank enter RPB The PB read into the microprocessor cor responds to that stored in conjunction with the Databank currently in memory EA6 3 Majors XRF ELEMENT FLT COL DET XTL ORD UPL LWL KV ANGLE OFFS OFFS C Ka NO C S 1 85 15 25 20 45005 Rb Ka NO F S 1 1 75 25 50 40 26 580 Th La NO F S 1 1 80 15 50 40 27 440 1 80 U La NO F S 1 1 75 25 50 40 26 125 Sr Ka NO F S 1 1 75 25 50 40 25 100 Y Ka NO F S 1 1 75 25 50 40 23 755 60 Zr Ka NO F S 1 1 75 25 50 40 22 470 Pb La NO F S 1
70. Place the sample in the water bucket so that it is covered remove and suspend on mesh bas ket beneath the balance and record the weight of the sample suspended in water to at least one decimal place 2 Calculation of results DW SG DS SW where S G specific gravity DW dry weight and SW suspended weight Quality Control The Geoscience Laboratories has a rock standard which should be checked at the beginning and end of each job Productivity A technician should be able to complete 100 deter mination per day Additional notes 1 The balance should be calibrated often 2 Note any sample peculiarities e g vesicles 3 Donotuse this method on fragile samples such as clays MS 12 1 Soil Moisture DETERMINATION OF THE MOISTURE CONTENT OF SOIL ASTM D2216 71 Introduction Moisture or water content of soil is the ratio ex pressed as a percentage of the weight of water in a given mass of soil to the weight of the solid particles Procedure 1 1 Record the weight of a clean dry container and lid W1 A tight fitting lid is essential 1 2 Place a crumbled sample loosely in the con tainer and replace the lid Weigh the container lid and contents W2 1 3 Remove the lid and place container lid and contents in an oven at 105 C until a constant weight is reached generally overnight 1 4 After drying remove container lid and con tents from oven replace the lid
71. This suite of elements Hf Ta Th U options Pb Sn has been traditionally difficult to determine in geological materials because the host minerals are often refractory difficult to dissolve and treat analyti cally Futhermore these elements usually occur in discrete accessory mineral phases thus meaning spe cial attention must be paid to sample collection and preparation Finally these elements are usually found only at trace levels in most geological materials ICP MS provides the low determination limits required by geologists Elements in the T5 package have varied geological significance and although determined as a group these elements are not used as a single suite Ta and Hf found in rock forming and accessory minerals are used extensively to characterize the tectonic setting of basalt and granite Ta U Sn Th are used to monitor or evaluate processes that control the formation and differentiation of magma within magma chambers They are also used to discern the possible ore potential in granitic rocks Pb is incorporated into either galena PbS as a major constituent or at trace levels into potassium feldspars common in granites Because three Pb isotopes are produced by the radioactive decay of U or Th the assessment of the amount of lead present in a sample can be a preselection criteria for geochronology samples Tl is a rare element that is often associated with Au Ag and PGE minerals Other elements such
72. a hot plate and bring the contents to a boil Adjust the temperature of the hot plate so that violent boiling does not occur Transfer 200 ml boiled and cooled distilled water to a clean 600 ml beaker Add 50 ml of saturated boric acid solution Add 5 ml sulphuric acid After 10 minutes grasp the crucible around its centre with the tongs hold the lid in place with a stirring rod and transfer the crucible and lid into the 600 ml beaker containing 200 ml boiled distilled water 50 ml of saturated boric acid and 5 ml of sulphuric acid 4 Measurement of Ferrous Iron 4 1 1 4 1 2 e g Fill the burette with standardized KMnO solution Immediately following dissolution use the glass buret and titrate the contents of the 600 ml beaker with 1 10N 0 1 N potassium per manganate Stir thoroughly throughout the titration to a faint pink end point that persists for several seconds Calculate the Fe from the titre Gh fig TMnr eba rd g Sample ml KMnO 5 21 Eq 0 006181g g Sample 0 223 _ 5 21 x 0 006181 g 1 214496 Fe 0 223 g x 100 4 Fe 4 1 4 Calculate the FeO gt from the FeO 71 8 55 8 1 286 1 286 Fe Fe 0 159 7 2 x 55 8 1 430 gt Fe x 1 430 EA15 3 Ferrous Quality Control The quality of the analysis is controlled by running a standard reference material MRB 11 7 37 Fe and a blank The blank should yield results of le
73. a hot plate and slowly evaporate the contents to dryness Cool moisten with distilled water add 5 ml of concentrated HNO and 5 ml of HF and again evaporate to dryness Cool add 20 ml of HNO 1 1 and again evaporate to dryness Heat the contents of the dish for a further 30 min after the salts appear to be dry Cool add 20 ml 1 1 HNO previously boiled and cooled to remove oxides of nitrogen Add 10 ml of 4 5 boric acid solution Cover and digest the contents on a hot plate until dissolution appears to be complete Filter through a 12 5 cm Whatman No 40 paper into a 100 ml volumetric flask Police the dish and wash with distilled water having a few drops of colourless 1 1 HNO Transfer all washings to the filter paper Wash the filter paper several times with dis tilled water having few drops of colourless 1 1 After filtration and washings make to volume in a 100 ml volumetric flask with distilled water This is your original solution 4 Measurement of P O concentration 4 1 4 1 1 Pipet a 50 ml aliquot into a 100 ml volumetric flask from the original solution The splitting of the original solution 100 ml may be done with a dry pipette or conveniently as follows Rinse aclean pipette with the original solution and transfer the rinsings to a 150 ml beaker 4 1 2 Pipet a 50 ml aliquot into a 100 ml volumetric flask then rinse the pipette with water into the beaker 4
74. against the gravita tional forces The divider separates the two mineral streams directing them into bins at the end ofthe chute The vibrating chute has a forward inclination which controls the speed at which minerals move down the chute This is normally set at about 20 to 30 degrees The chute also has a side inclination the setting of which controls the gravitational force on the mineral grains This is usually set at about 15 degrees for the first few passes but may be increased to around 60 degrees in the later stages of a mineral separation The strength of the barrier field is controlled by a rheostat magnetic separations separate the strongly magnetic minerals first from the sample and proceed in order of decreasing magnetic susceptibility Therefore the bar rier field is initially very weak so that the ferromag netic and strongly paramagnetic minerals can be removed As the mineral stream enters the middle of the chute the gravitational forces on the mineral mixture will act SO as to impel the mineral grains toward the lower edge of the chute As they travel through the centre of the chute they interact with the magnetic barrier field Those minerals less magnetic than the field will carry on through this region towards the lower edge of the chute those minerals with a magnetic force equal to or greater than the barrier field are deflected by it and stay on the upper side of the chute As the strength of the barrier field is
75. already on file the operator enters ACH FE and values given as defaults will be those entered previously To change a parameter the new value is typed in Once an element has been entered into the table it cannot be removed One way to deal with unwanted channels is to rename them using a nonsensical symbol e g XX YY ZZ As new channels are required these channels can be renamed To see the conditions established for any specific channel the instruction is PCH FE The system will respond with ELEMENT FLT COL DET XTL ORD UPL LWL MA ANGLE OFFS OFFS FE Ka NO C FS 1 1 80 15 60 50 57 470 00 00 To see all conditions for all channels in the parameter bank enter the instruction PCH The system will respond with ELEMENT FLT COL DET XTL ORD UPL LWL KV MA ANGLE OFFS OFFS Fe Ka NO C FS 1 1 80 15 60 50 57470 Al NO C F 3 1 79 25 40 75 144 540 Ti NO C F 1 1 75 25 40 75 85 925 80 Mn Ka NO C F 1 1 80 15 60 50 62 950 80 K Koa NO F F 1 1 75 25 60 50 136 730 Ca Ka NO C F 1 1 75 25 40 75 113 085 Si Ka NO C F 3 1 75 25 60 50 108 670 Na Ka NO C F 5 1 75 25 40 75 55 080 1 00 Mg Ka NO F F 5 1 75 25 40 75 45 225 1 00 P Ka NO C F 4 1 80 15 40 75 140 935 1 00 It is useful to include in each parameter bank assembly the folowing channels for instrument check EA6 18 Majors XRF ELEMENT FLT COL DET XTL ORD UPL LWL KV ANGLE OFFS OFFS Cu NO C S 1 1 85 15 25 20 45 005 Al Ka NO F F 3 1 75 25 25
76. and allow to cool 1 5 Weigh the container lid and contents W3 Calculation W2 W3 96 moisture in sample wa wi 100 13 1 FIRE ASSAY Introduction Fire assaying is used to determine the precious metal content of rocks and ores Determinations of gold and silver present in abundances exceeding 0 01 oz ton for Au and 0 10 oz ton for Ag are made by fire assay and gravimetric techniques Gold platinium and palladium present in lower abundances are determined by Atomic Absorption Spectroscopy see Section EA21 follow ing fire assay preconcentration Special caution is required when dealing with unusual rock matrices and it is critical that the flux composi tion be modified according to the composition of the sample If an estimate of the gold or silver content is available then the weight of the sample used can be adjusted Precious metals are normally present in nature at con centrations of less than 1 ppm Furthermore their distribution within a sample may be very in homogeneous The fire assay procedure enables a large sample to be analyzed in order to optimize precision and accuracy Safety advisory A lead flux is used to prepare the button Lead is a known carcinogen and has been linked to various chronic forms of cancer The working area is a lead control area Specific attention should be paid to the following points 1 Ensure that fluxes are mixed ONLY in the vented hood 2 Do not
77. and dilute to 1 liter with distilled water Alizarin fluorine blue 3 amino ethylalizarin N N diacetic acid stock solution 0 01M Suspend 0 963 g of alizarin fluorine blue in about 100 ml of distilled water Add 2 ml of concentrated ammonium hydroxide and shake until the dye has com pletely dissolved Add 2 ml of glacial acetic acid and dilute to 250 ml with distilled water Store in an amber bottle at 4 C Lanthanum nitrate stock solution 0 01M Dis solve 1 082 g of lanthanum nitrate La NO3 4 6H O in 100 ml of distilled water and dilute to 250 ml with distilled water Alizarin reagent Mix the solutions in the following order 300 ml of acetate buffer 150 ml of acetone 50 ml of t butyl alcohol 36 ml of alizarin fluorine blue stock solution 40 ml of lanthanum nitrate and 2 ml of Brij 35 Dilute to 1 liter with distilled water The reagent is stable for at least 2 days Store at 4 C when not in use EA23 2 1 7 EDTA reagent 1 w v Dissolve 10 g of tetrasodium ethylenediamine tetracetic acid along with a few pellets of sodium hydroxide in distilled water and dilute to 1 liter 2 Standard F solution preparation 2 22 2 3 Stock standard solution 100 ug F ml Dis solve 0 2207 g of sodium fluoride in distilled water and dilute to 1 liter Store in a polyethylene bottle Working standard solutions Prepare 0 1 0 2 0 3 0 5 and 1 0 ug F ml standard solutions by serial dilution of t
78. and mix sample and flux with a small teflon coated spatula see Note 3 2 3 Transfer quantitatively to a graphite crucible and place on a silica tray see Note 4 2 4 Fuse in a muffle furnace for 15 minutes at 1000 C 2 5 Open the oven door and pour the fused sample while hot using crucible tongs and protective gloves into a 250 ml nalgene beaker contain ing 60 ml of 1096 HF solution 2 6 Add 4 5 g of boric acid crystal to the beaker and add 100 ml of distilled water 2 7 Placeateflon coated stirring bar in the beaker and place on a magnetic stirrer unit Stir for 30 to 60 minutes depending on the type of sample or until dissolution is complete see Note 5 2 8 Filter the solution using Whatman 41 filter paper 12 5 cm into a 200 mi nalgene volumetric flask Wash filter paper and beaker several times with small amounts of distilled water Make to volume with distilled water This is the original stock sample solu tion A 29 Prepare solution to be used for the AA deter mination of CaO MgO and Fe O 29 1 Pipet 10 ml of sample stock solution A into a 100 ml nalgene volumetric flask 2 9 2 Pipette 5 ml of 30 000 ppm Sr buffer solution to the flask and make to volume with distilled water 2 10 Prepare solution to be used for the AA deter mination of SiO and AL O 2 10 1 Pipet a 50 ml aliquot of sample stock solution A into a 100 mi nalgene volumetric flask 2 10 2 Add 10 ml of 30 000 ppm
79. and the fraction of oxygen is 1 0 4675 0 5325 The MA values for Si and O at the Sr K alpha line are 12 8 and 2 6 respectively T the accumulated total MA 465 INPUT SIO2 SI 470 SI SI 100 471 T T SI 4675 12 8 SI 5325 2 6 475 PRINT INPUT AL203 AL 476 AL AL 100 477 T T AL 5291 10 3 AL 4709 2 6 480 PRINT INPUT TOTAL FE203 FE 481 FE FE 100 482 T T FE 6994 66 8 FE 3006 2 6 485 PRINT INPUT MGO 486 MG MG 100 487 T T MG 6032 8 1 MG 3968 2 6 490 PRINT INPUT CAO A 491 CA 100 492 T 7147 33 7 CA 2853 2 6 495 PRINT INPUT NA20 NN 496 NN NN 100 497 T T NN 7919 6 3 NN 2081 2 6 500 PRINT INPUT K20 gt KK 501 KK KK 100 502 T T KK 8302 29 5 KK 1698 2 6 505 PRINT INPUT TIO2 TI 506 TI 100 507 T 5995 43 3 TI 4005 2 6 510 PRINT INPUT P205 PP 511 PP 100 512 T 4365 15 6 PP 5635 2 6 515 PRINT INPUT MNO M 516 MM MM 100 517 T T MM 7744 60 5 MM 2256 2 6 520 PRINT INPUT CO2 CC 521 CC CC 100 522 D P 12720 26 525 PRINT INPUT H20 HH 526 T HH 100 8889 2 6 T 530 PRINT INPUT SULFUR SS 535 SS SS 100 536 T T SS 18 7 EA16 15 Traces XRF 540 HOME 545 PRINT DO YOU WANT TO INCLUDE BA AN
80. as x Ci RSD tC Eu Paul CA true i e the ratio of the interference contribution to the actual or true analyte concentration It is possible to predefine a value of RSD related to expected experimental precision below which the in terference is considered to be insignificant Thus for example if we define significance at RSD 0 01 1 then for a coefficient of x 0 01 we can write 0 01 C ue CA true The limiting ratio of interferent to analyte concentra tion is therefore 1 Conversely if the analyte con centration is expected to be more than the concentration of the interferent the interferent can be ignored For example Vanadium shows an ICP interference on aluminum with coefficient 0 15 Under normal cir cumstances this is a relatively high value for an inter ference coefficient and would not be ignored From the RSD criterion we can estimate limiting concentration ratios for a series of RSD values RSD 1 100 C V C AL 6 7 0 5 3 3 0 25 1 7 0 1 0 7 0 05 0 3 0 025 0 2 0 01 0 1 For levels of aluminum in silicate rocks of 5 15 and acceptable precision levels of 5 RSD 0 05 the concentration of vanadium would need to be between 1 5 and 4 5 for the vanadium interference to have any significant contribution As this concentration is not likely to occur in most silicate rocks the vanadium correction can be ignored in the determination of Al in silicates Interferences and the Dete
81. as Rb Cs Sr Zr and Nb can be deter mined in the T5 package Safety advisory Refer to the Safety Advisory Section in the Trace 4 elements page EA19 13 Method The method is similar to that used for the Trace 4 elements page EA19 14 Apparatus Refer to the Trace 4 method EA19 18 TABLE MS6 DETERMINATION LIMITS AND PRECISION FOR TRACE ELEMENTS T5 Element Determination Optimum Limit Range ppm ppm Hf 0 05 0 20 100 0 05 Ta 0 05 0 05 20 0 05 Th 0 10 0 10 100 0 10 U 0 10 0 10 100 0 10 Options Pb 0 10 0 10 100 0 10 Sn 0 50 0 50 100 0 50 TI 0 10 0 10 100 0 10 Rb Cs Sr Under Development Zr Nb Precision is quoted as the 95 Confidence Limit ug g for a value at 10x the determination limit i e absolute not relative Reagents Refer to the Trace 4 method Procedures Refer to the Trace 4 method Quality Control Refer to the Trace 4 method Table MS7 contains the data for the instrument check solution The validation of the current ICP MS method for the other T5 elements is in progress TABLE MS7 COMPOSITION OF T5 CHECK Element Rb Sr Zr Nb Cs Hf Ta SOLUTION Mean ppm 41 406 306 34 94 86 7 691 1 349 2 479 0 349 Accuracy is about 5 Productivity A technician should be able to complete 60 samples Std Dev 0 958 6 507 2 146 0 187 0 036 0 081 0 012 day This does not include data reduction and
82. be multiplied by 2 before reporting to obtain the correct concentration value ANALYTICAL CAPABILITIES Determination Limit ppm 5 Precision at the 95 confidence limit 26 at 10X determination limit 50 ppm is 5 ppm absolute Chromium Cr STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm stock Cr solution to prepare 1 0 2 0 4 0 and 8 0 ppm work ing standards Add 10 ml of 10 000 ppm for every 100 ml of working standard prepared 1 ml 1000 ppm K INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 357 9 Spectral Band Pass nm 0 2 Background Correction OFF Flame Description Nitrous oxide acetylene Fuel rich red cone WORKING CONDITIONS Sensitivity 1 ppm Cr solution reads 0 090 absorbance Calibration Set 1 ppm to read 0 50 Working range 1 0 to 8 0 ppm INTERFERENCES The nitrous oxide acetylene flame overcomes most supressions observed with an air acetylene flame Ionization suppression is eliminated by addition of 1000 ppm to the working standards Most rock samples have sufficient alkali concentration to eliminate the need for addition of K to the sample solution NOTES 1 To reduce signal noise the gain is reduced by setting working standards to one half values during calibration The subsequent readout for samples must be multiplied by 2 before reporting to obtain the correct concentration value ANALYTICAL CAPABILITIES Determination Limit ppm 10 Prec
83. bottom of the mold Allow the mold and contents to cool Remove the bead from the mold Label the mold with a gummed tag on the upper surface that is not in contact with the Pt and place itin a clean sample bag to protect it from contamination Crack and re fuse imperfect beads uneven thickness rippled nonhomogeneous colour distribution These beads are now ready to be analyzed by the Philips 1400 XRF spectrometer 1 2 Majors XRF Silicate Rock Analysis Automated Preparation of Fused Beads A Leco FX 200 Fluxer is used to prepare rock powder samples for XRF analysis Prepare sample flux lan thanum oxide mixtures as described in the manual procedure above 1 2 1 1 2 2 1 2 3 1 2 4 1 2 5 1 2 6 1 2 7 1 2 8 1 2 9 1 2 10 1 2 11 1 2 12 1 2 13 1 2 14 1 2 15 Ensure that crucibles and molds are clean Inspect top of burners If necessary use the wire brush to clean the burner heads Ensure that gas supplies are sufficient and are turned on Ensure that the spark electrode and ther mocouple have not been disturbed They should be located 3 mm from the pilot arm Tum the fumehood on Tum the power switch to the ON position Push and hold the PUSH TO IGNITE button until the PILOT LED stays on 20 25 seconds Add prepared sample mix to the crucible Select the number of burners required by pressing the BURN SEL key the appropriate number of times and fi
84. called REEA containing Ce and Lu is prepared by serial dilution of the appropriate 1000 ppm single element standards 200 ml of a 100 ppm multielement standard called REEB containing Gd Dy Tb Ho Er and Tm is prepared by serial dilution of the appropriate 1000 ppm single element stand ards 200 ml of a 100 ppm solution containing Ru and Re is prepared by serial dilution of the appropriate 1000 ppm single element stand ards 200 ml of a 10 ppm solution containing Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb and Lu called REEA is prepared by serial dilution of the 100 ppm solutions REEA and The REESTD calibration standard contain ing Y the REE Ru and Re is prepared by serial of the appropriate 10 ppm calibration standards The REEB and REEA interference solutions are prepared by weighing 0 200 g of the ap propriate 100 ppm stock solution transferring to a 250 ml volumetric and making up to volume The 2 ppm Ba interference solution is prepared by weighing 0 50 g of 1000 ppm Ba stock solution and transferring to a 250 ml volumetric Instrument control solution identified as CHK2 was prepared by collecting the remain ing solution after analysis until about 3 liters was collected The solution was allowed to sit for about two weeks and then filtered through a 45 micron filter 2 Measurement of Analyte Concentration The operation of the Elan 250 and the measurement of the analyt
85. can be displayed by pressing the RECALL key When a calibration curve is recalled the printersample number will revert back to the next sample number that existed at the time the curve was stored The number dis played with the curve selection menu is the program number associated with the curve The furnace pro gram is recalled from the RECALL menu Store Menu The STORE key is used to accept store newly developed furnace methods and furnace curves Make sure atomizer is set for CTF selection 6 of Mode menu Furnace curves will only be displayed when in the concentration mode selection 4 of Mode menu Back up stored methods with a hard copy using the graphics printer If you wish to save a newly developed method you MUST dosothrough theSTORE key while this new method is recognized as the current method see recall menu or it will be erased when a new method is selected or developed As each new method is accepted it is assigned the next highest number in the user created series 150 to 349 In addition you may also overwrite existing methods which you have created Only the methods created by you can be stored or overwritten Factor supplied methods can be used to develop new methods but cannot be overwritten About Furnace Methods The 188 microprocessor has an overall storage capacity for 349 furnace methods divided into two categories of permanent factory supplied methods and storage space for methods developed
86. can occur due to detector effects or due to nonspecific matrix effects caused by the analyte itself and the calibration function is best described by a polynomial expression C A2 52 Al S or C S 2 52 1 5 AO In a complex system containing a large variety of emitter atoms and ions there will be a large number of spectral lines These lines have a very narrow natural band width but do experience a degree of broadening Doppler effects etc It is natural to expect that any given analyte line will have a relatively large number of lines due to concomitant elements nearby It is also quite probable that a concomitant can have a line at exactly the same wavelength as that of the analyte direct overlap or close enough to it to be virtually inseparable by the optical system of the spectrometer It can be shown that for all but the cases of direct overlap the ability to separate the lines will depend on the band width of the lines the degree of separation and the slit width of the exit slit in the mask at the Rowland circle of the spectrometer Quantifying Interferences The contribution from the interferent will manifest itself as an apparent concentration of analyte higher than that expected the true analyte concentration ST SA SI where ST total signal SA analyte signal SI in terferent signal contribution C Al ST AO SD AO 1 5 A0 AI SD
87. ceased completely 20 minutes is usually required for complete decomposition 3 3 After 30 minutes take the second reading of the volume of 3 4 Observe the temperature of the air surrounding the apparatus and also the barometric pressure at the time of the reading 3 5 Find the correction factor for temperature and pressure from the table see Association of Official Agricultural Chemists 1955 pp 945 951 4 Recording and Calculation of the results A record Form CH1 is kept of the following readings correction factors and the computed results for each sample A Sample Number B Weight of sample analyzed usually 0 850 g or 1 700 g C Room temperature D Correction factor for the temperature 1 2 m First reading a volume of CO b corrected first reading obtained by multiply ing the first reading by its correction factor Second reading a volume of CO b corrected second reading obtained by multi plying the second reading by its correction factor G Calulation Corrected second reading minus cor rected first reading or Fb Eb H Corrected first reading minus 4 percent of the value of I 4 percent of the value of is added to One tenth of the values of H and 1 represent the percent CO from calcite and dolomite respectively when the 1 700 g sample weight is used see Associa tion of Official Agricultural Chemists 1955 pp 127
88. celles de l auteur ou des auteurs et ne doivent pas tre interpr t es comme des nonc s officiels de politique gouvernementale Vous tes enti rement responsable de l utilisation que vous en faites Le contenu ne constitue pas une source fiable de conseils juridiques et ne peut en aucun cas faire autorit dans votre situation particuli re Les utilisateurs sont tenus de v rifier l exactitude et l applicabilit de tout contenu avant de l utiliser Le MDNM n offre aucune garantie expresse ou implicite relativement la mise jour l exactitude l int gralit ou la fiabilit du contenu Le MDNM ne peut tre tenu responsable de tout dommage quelle qu en soit la cause r sultant directement ou indirectement de l utilisation du contenu Le MDNM n assume aucune responsabilit l gale de quelque nature que ce soit en ce qui a trait au contenu Liens vers d autres sites Web Ce contenu peut comporter des liens vers des sites Web qui ne sont pas exploit s par le MDNM Certains de ces sites pourraient ne pas tre offerts en francais Le MDNM se d gage de toute responsabilit quant la s ret l exactitude ou la disponibilit des sites Web ainsi reli s ou l information qu ils contiennent La responsabilit des sites Web ainsi reli s de leur exploitation et de leur contenu incombe la personne ou l entit pour lesquelles ils ont t cr s ou sont entretenus le propri taire Votre utilisation de ces si
89. compounds are relatively insoluble Silver is associated with Pb Zn ores CADMIUM Greenockite Cd2SO4 Cadmium is associated with ZnS ores Safety advisory 1 Exercise extreme care when using any acids and fluxes required for sample dissolution Their use should only be attempted after the appropriate MSDS sheets have been read and the safe handling and first aid procedures understood Acids should only be handled in a fume hood designated for their use and proper protective equipment wom Proper ventilation is required when handling fluxes which create a dust control problem Before operating an atomic absorption spectrophotometer ensure that the proper instruc tions found in the manufacturer s operator s manual are understood Preliminary safety checks are noted in the section of this manual outlining the operation of an atomic absorption spectrophotometer Cylinders of compressed gas used as fuel and oxidant for flame atomic absorption spectrometry must be securely fastened and have the proper regulator Ensure that the system has no leaks and the gas hoses are in good condition Review the section on compressed gases found in the Safety Manual for the Geoscience Laboratories Apparatus Atomic Absorption Spectrometer EA17 2 Intermediate Granite Pegmatite 15 3 1 50 25 30 50 15 5 40 10 3 6 20 70 50 200 1600 950 700 20 40 60 1400 400 400 60 40 0 2 A Varian AA 775 B Varian 5
90. computer will return to the RG mode Enter CON channel by channel enter the standards numbers defined at 5 5 and the corres ponding concentrations units of concen trations used here determine units output in analysis Enter CAL at RG mode and 1 at the prompt DEGREE for first order curve EA18 18 5 8 Enter N RETURN for normal weighing equal weighing of all points minimizes ab solute error 5 9 Enter Y yes to Save curve in memory or N no not to save curve 5 10 Enter VER or MOD for verify or modify the calibration results see JY48P software manual for further explanation At the end of VER or MOD mode make sure to CAL calibrate and accept Y for yes the calibra tion curves Repeat steps 7 8 until calibration is complete 5 12 When all calibration curves have been ac cepted enter EN to exit the RG routine 5 13 Enter Y yes to save the standard file If this is not done all files will be lost and you must repeat the entire calibration process 5 14 Enter XXXXXX to store the standards file on disk for later use XXXXXX alphanumeri cal characters for the standards filename 5 15 Enter Y yes to save the recent changes up dated curves in the Table on disk 5 16 Enter XXXXXX the name to store Table parameters on disk for later use If no name is given parameters are not saved on disk but are still retained in memory NOTE In the Table file a low and a high standard are defi
91. confidence limit 20 for the mid range value is 4 relative e g 10 0 4 The accuracy is comparable to the precision based on data collected from standard reference materials Productivity A technician should be able to complete 20 determina tions per day Additional Notes 1 Typical blank values 5 10 C 10 min If a higher value is observed the air scrubber solution should be changed 2 Do not wash the anode with water since the precipitated AgI will plug the frits Carbonate Carbon 3 Any volatile acid or base not removed by the scrubbing solution will interfere with the analysis Potentially interfering gases which the scrubber removes include H S CL HI HF SO and SO Another scrubbing solution which is effective for removal of chlorine and sulphur compounds is a saturated Ag SO solution containing 3 H O at pH 3 4 Although running standard samples is not required for calibration it is desirable to confirm proper operation of the apparatus and coulometer by run ning standards such as primary standard grade calcium carbonate periodically 5 Potassium iodide crystals should appear in the anode compartment at all times 6 A variety of mineral acids can be used for evolu tion of CO The following acids are most com mon a 2N HCIO b 2N H SO c 2N must be taken to insure the HCI gas does not overload the scrubber Bibliography Instruction Manual f
92. count axis is then printed and either accepted or changed and the plot put out on the screen The screen can be dumped to the dedicated printer LASO for a hard copy output of the plot If a series of scans is to be obtained for the same angle range and under the same conditions the instructions can be set into a JOB stored in the parameter bank For example to setup a job for a scan from 45 to 50 increment 0 05 under the conditions normally used for measuring copper the following steps are carried out AJB 1 Assemble job 1 1 EJB The first step is assumed to be the end of the job default The first instruction is then entered 1 EJB SCH CU 2 EJB PTS 1 0 3 EJB SLF 45 0 4 EJB STS 50 0 0 05 5 R To perform the scan one types WDD XXXXXX SJB 1 Start Job 1 There are many combinations of instructions which can be included in a jobfile multiple scans angle calibration sample measurement To delete a jobfile from the PB type DJB 1 Running the Sample Once the Measurement Program MP Link Program LP rate correction set RC and the Calculation Parameter CP sets have been defined it is possible to run samples on a routine basis EA6 30 Majors AA DETERMINATION OF MAJOR ELEMENTS SiO2 A1203 Fe203 MgO CaO FLAME ATOMIC ABSORPTION SPECTROMETRY Introduction These methods are used only where the sample matrix makes the constituents concemed unsuitable to b
93. details see T2FORM Details T2CON The T2CON program was written to store concentration data for the T2 elements determined by the JY 48P ICP OES The program will ask for the concentration filename in which the concentration data are going to be stored This file will appear on the system disk as CON The program will now ask the user to enter 1 The JY file name to start 2 The JY file name to end the sequence 3 The duplicates and or SRM filenames if there are any EA18 21 Traces ICP OES NOTE JOBFIL To ensure the proper execution of the 2 program the sample identifiers for the JY data must have the form LLNNN DAT where LL are letters and NNN are numbers When a batch of samples are run on the JY the sample identifiers are numbered in sequence e g PW125 to PW175 inclusive for a batch of 51 samples A batch of samples is a group of samples from one to ten different jobs It is important that NO duplicates are allowed within the above sequence The duplicates should be numbered with D appended to their JY filenames For examples PW125 and PW170 will have their duplicates labelled as PW125D and PW170D respectively SRM identifiers do not have to follow this rule Refer to the example dialogue included with this report The data are stored into the concentration file CON which was created at the beginning of the execution of this program and is ready for the final reporting program T2FORM JOBFI
94. determination limit of the method Example Consider niobium in a matrix containing 5 Fe 4 Al 4 Ca 2 Mg and 0 2 Ti Calibration curve coefficient A1 for Nb 5 6 Calibration curve coefficient for Nb 0 5 Measured interference coefficients x for matrix ele ments on Nb x Fe 0 000027 x Al 0 00022 x Ca 0 000030 x Mg 0 00012 x Ti 0 00018 Niobium blank intensity 90000 counts EA18 11 Traces ICP OES 0 1 90000 5 6 0 05 ppm 5 ppm rock PDL A From the interferent element concentrations expected in solution i e C Fe 500 ppm C Al 400 ppm C Ca 400 ppm C Mg 200 ppm C Ti 20 ppm we can calculate the total matrix contribution CM where CM SUM x C Contributions x Fe C Fe 0 0135 ppm solution X ADC AD 0 0880 ppm x Ca C Ca 0 0120 ppm x Mg C Mg 0 0240 ppm x Ti C Ti 0 0036 ppm CM 0 1411 ppm solution 14 ppm rock and PDL M 0 1 CM 0 0141 ppm 1 4 ppm rock PDL 0 05 0 0141 0 06 0 07 ppm 6 7 ppm rock Thus the contribution of error in the determination of matrix components results in an effective PDL of 6 7 ppm rock in the matrix of interest We can use the expression derived previously to deter mine the relative importance of the matrix corrections Le RSD x C CA and if we accept a value of RSD 1 as the limiting error contribution we can establish critical ratios of C CA for the various interferents
95. dispersed by a grating in an optical system and the intensities of the spectral lines are measured generally by photometric means although photographic recording can be used Instrumentation typically consists of either a ascanning monochromator with a single detec tor placed behind an exit sliton the Rowland circle sequential measurement or of b a polychrom ator with a number of photomultiplier detectors positioned behind fixed slits cut along the optical axis providing simultaneous wavelength selective detection direct reader 3 The ICP OES spectrometer in the Geoscience Laboratories is a Jobin Yvon JY48P direct read ing instrument employing a holographic grating with 36 channels dedicated to elements of geological interest These elements along with their channel numbers and first order analytical wavelengths are listed in Table ICP 4 The JY48P instrument employs a PlasmaTherm source generator and torch with maximum plas ma power of 2500 watts Standard operating con ditions average 1800 watts The source system is not under computer control and all settings must be established and reproduced manually Al though other nebulizer systems are available the Geoscience Laboratories has consistently used a concentric glass nebulizer Meinhard C3 type with high salt capability This nebulizer along with a glass spray chamber and quartz torch are used for sample introduction aerosol formation and excitation
96. distilled water to each of the funnels Continue as from step 3 8 to 3 14 4 Measurement of Au concentration 4 1 Set upthe Perkin Elmer 603 atomic absorption spectrophotometer equipped with a HGA 500 programmer and graphite furnace and utilizing the AS 1 auto sampler according to the proce dure described in the manufacturer s operation manual The atomic absorption signal is measured as peak height with a Perkin Elmer Model 56 chart recorder The instrument parameters are listed in the following table Instrument Parameters Wavelength 242 8 nm Lamp Current 8mA Slit with setting 4 0 7 nm Deuterium arc back ground corrector on Signal absorbance Recorder Power servo Chart Speed 40 mm min Range 1mV P E Model HGA 500 graphite furnace and AS 1 auto sampler Purge gas argon Sample Volume 20 ul Rinsings water Graphite furnace program steps A Drying Step Temperature 120 C Ramp time 10 sec Hold time 10 sec B Charring Step Temperature 800 C Ramp time 10 sec Hold time 5 sec C Atomization Step Temperature 2700 C Ramp time 3 sec Hold time 3 sec Enter 5 and press REC key READ key and INT FLOW key 4 2 Record the absorption signals on chart paper Measure the peak height of the standards and draw a calibration graph 5 Calculation of the results The absolute quantity ng of Au in the sample solu tion is read with the aid of a calibration graph estab lished using 5 10 and 20 ng standards The net
97. eat drink or smoke in the room 3 Wash your hands after handling flux 4 Weara fire resistant lab coat in the fire assay area Keep this coat in the area and do not remove it from the assay suite except to be laundered 5 Wear a full face shield and insulated gloves when using the furnace 6 Perform all parting processes in a fume hood 7 Wearsafety glasses when not wearing the full face shield Fire Assay 8 Read MSDS sheets for all chemicals used in this method i e litharge sodium carbonate silica and borax glass Method There are three fire assay methods l A regular gold and silver fire assay utilizing gravimetry 2 Afireassay graphite furnace technique for Au Pt and Pd 3 A fire assay nickel sulphide concentration techni que with analysis by instrumental neutron activa tion analysis Method 1 consists of the following techniques 1 Sample preparation the weighing and mixing of the rock powder and flux 2 Preconcentration the melting and pouring to form a button removing and cubing of the button and cupelling to produce a prill 3 Determination weighing and parting 4 Calculation of the results weighing of the gold and converting this weight to oz ton If concentrations of less than 0 01 oz ton Au Pt or Pd or 0 10 oz ton Ag are to be determined the prill is passed to the Chemistry subsection for dissolution and analysis by graphite fumace AA Method 2 The nickel su
98. entrainment of grains does not occur The side slope is also increased to about 60 so that the gravitational component is in creased with a corresponding increase in the magnetic field This allows for a more precise separation as small differences in magnetic susceptibility can now be exploited Special feed troughs are available so that the grains do not spill and the feed rate is narrowly control led The settings in these final stages are a matter of trial and error Frequent checking of the separated products using the binocular micro Scope grain mounts and the X ray diffrac tometer will help control the quality of the separation Magnetic Separation 1 10 Often the range of magnetic properties in the mineral being separated are such that it does come clean at a relatively narrow magnetic range and therefore the final product will con tain some impurities Most of these may be removed by heavy liquid separation 1 11 The final product will still contain a few im purities which will have to be removed by hand picking under a binocular microscope uality Control A grain mount should be made of the final product to demonstrate its purity refer to the section on optical mineralogy page M9 1 Productivity Variable Dependant on the volume and the difficulty of the separation Bibliography Flinter B H 1959 The magnetic separation of some alluvial minerals in Malaya Am Mineralogist 44 pp 738 51
99. files you wish to retain the operator can check the disk directory by command DIR DY 1 to obtain the directory listing When the disk has been formatted the system returns to the routine cursor and waits for further instruc tions To exit from the FORMAT routine the operator types Ctrl C the system returns to the RT 11 operat ing system which responses with the type cursor at the left margin The disk is now initialized using one of several instruc tions EA18 3 iraces ICP OES INI BAD 1 INI BAD SEG 8 DY1 INI BAD VOL DY1 INI BAD VOL SEG 8 DY1 The first is used to initialize a single density disk with no volume identifier the second also with no volume identity is used for a double density disk Inclusion of the VOL part of the command allows the operator to assign a volume number and owner identity to the disk The SEG 8 permits a greater number of files to be stored on the double density disk Including BAD into the instruction allows the system to seek out bad blocks defects on the disk and identify their location After the initialization command the system asks ARE YOU SURE and after a Y response carries out the procedure When initialization is complete the system returns to the RT 11 operating system The Directory After initialization the operator can confirm the num ber of available storage blocks by typing DIR or DIR DY1 To obtain a directory of the system disk th
100. frequently used for the decomposition of organic matter The loss of certain metals lead cadmium mercury arsenic selenium is possible through volatilization the formation of insoluble sili cates or retention on the ashing vessel If the tempera ture for ashing is held at 450 C volatile metals such as lead zinc and cadmium are normally retained Reten tion on the ashing vessel is reduced if new vessels are conditioned in the muffle furnace at 550 C before use and kept specifically for ashing purposes 6 1 Weigh 20 00 g of dry material into a pyrex beaker conditioned for ashing purposes see Notes 1 2 6 2 Position the beaker on a silica tray and place in the cool furnace CAUTION The furnace must be in a vented fume hood Ensure that no smoke enters the room 6 3 Set the furnace temperature control at 200 C and allow the temperature to rise The furnace door needs to be held open a few centimeters to allow air to enter the ashing chamber and the smoke to be vented 6 4 Raise the temperature of the furnace in 50 increments once it has reached 200 C hold ing each temperature until the formation of smoke has subsided When an increase in temperature produces no additional smoke charring is essentially complete and the fur nace doors may be closed 6 5 Set the furnace to 450 C and complete the ashing for 5 hours see Note 3 6 6 Whenashingis complete allow the beakers to cool 6 7 Ad
101. furnace atomic absorption spectrometry Element Lamp Band Wave S H Current width length Bkg ma nm nm ma Au 5 1 0 242 8 3 0 Pd 5 0 3 247 6 25 Pt 5 0 5 265 9 25 Background Correction Smith Hieftje See Section 4 4 21 page 4 58 of the Video 22E Operator s Manual S H background correction is selected from option 3 of the Mode menu Set the background current and adjust PM voltage so that the energy meter is in the green zone Increase Signal HCL current until its energy matches that of the Back ground Deuterium Arc The intensity of the D2 is automatically set during the autozero routine to match the intensity of the hollow cathode lamp Select D2 from option 3 of the Mode menu Key A Z and READ to allow the D2 arc current to increase until the D2 reference intensity is balanced with the reference Io beam of the HCL Graphite Furnace NOTE In the case of low intensity resonance lines that require upper range high voltage settings the D2 arc may exceed the HCL intensity even at the minimum operating current of the D2 arc In this case increase the lamp current and decrease the PM voltage or insert the D2 arc neutral density filter into the beam of the D2 arc See Figure 4 16 page 4 61 Reset the D2 arc by keying A Z and READ NOTE To switch off the D2 arc go through the MODE key and press 3 ENTER to change to A or A bkg S H FOURTH Select the Recall menu and call up the furnace method for analyz
102. given on page EA14 1 Since most instrumental analytical techniques do not readily provide information about the oxidation state of constituents it is necessary to employ more classical volumetric techniques Mossbaur spectroscopy has been used to distinguish iron oxidation states in rocks and minerals but is not suitable for routine analysis The rock sample is decomposed by heating with a mixture of sulphuric and hydrofluoric acids in a covered platinum crucible Most of the iron bearing minerals are decomposed by this procedure forming soluble ferrous and ferric sulphates The crucible lid and contents are placed in a mixture of boric and sulphuric acids The solution is titrated against stand ardized potassium permanganate which oxidizes the ferrous iron to ferric iron 5 Fe 5 Fe 5e 0 771V Se MnO 8H Mn 4 1 51 V MnO 5 Fe Mn 5 Fe 4 H O Boric acid is used to remove excess fluoride ion B OH 2H 0 B OH B OH 4HF BF 3H 0 H 0 The method is similar to that described by Goldich A number of potential interferences are highlighted in the Quality Assurance portion of this method below There are a number of alternative methods in the literature Wilson s method is based on the reduction of ammonium metavanadate NH VO by ferrous iron Unfortunately all methods suffer from various sources of determinate error The met
103. hydrometer scale should be read at the top of the meniscus A working temperature of 23 C is assumed but if very different then a correction is applied in the calculation Table GSA2 8 Grain Size Calculations The calculation of grain size distribution follows the flow chart shown in Figure GSA2 The percentage of particles of size less than 2 25 microns is determined using the following calculation MS4 11 Grain size Analysis Z 8 1 Percentage of soil in suspension SS ss 100 where SS percentage of soil remaining in sus pension at the level at which the hydrometer measures the density of the suspension corrected hydrometer reading a correction factor to be applied for the reading of the hydrometer See Table GSA4 W oven dry weight in grams of soil dis persed and used for the hydrometer readings TABLE GSA4 CORRECTION FACTOR Specific Gravity Correction Factor g cc a 2 95 0 94 2 90 0 95 2 85 0 96 2 80 0 97 2 75 0 98 2 70 0 99 2 65 1 00 2 60 1 01 2 99 1 02 2 50 1 03 2 45 1 05 8 2 Diameter of soil particles D 1 D K lA where D diameter of particle mm constant depending on the temper ature of the suspension and the specific gravity of the soil particles Table GSA2 L distance from the surface of the sus pension to the level at which the density of the suspension is known cm T interval of time from beginning of sedimentation to the taki
104. in the Appendix C follow ing Determination of Major Elements X ray Fluorescence Spectrometry page EA6 6 It is important to appreciate the manner in which the computer and microprocessor control the instrument and how the operator can control the system Operator commands to the system software are via three letter acronyms Before the spectrometer can analyze samples it must know what information is required and how the data are to be acquired After acquisition of data the com puter must know how to process the data to provide corrected results Two separate areas or memory banks are used to store this information These are referred to as the Databank DB and the Parameter Bank PB Infor mation relating to a particular set of samples is stored under one name that is common in both banks The Databank provides information that is used by the computerto calculate corrected DATA The Parameter Bank is usedto set the physical PARAMETERS on the Majors XRF instrument so information is acquired in the correct manner The information stored in the Databank includes link programs LP which interface between the measuring program and the calculation parameters corrections calibrations etc calculation parameters CP correction parameters RC count rate correc tions NOTE These are all concerned with data processing To read what is in the DB type PDB Print DATA Bank The contents of the
105. in the instrument s computer Samples are either fused with lithium metaborate sili cate rocks or pressed into pellets carbonate rocks The prepared samples are analyzed using an X ray fluorescence spectrometer Carbon sulphur and loss on ignition data must be acquired prior to preparing samples for X ray analysis Apparatus Balance capable of weighing 1 20 g 0 001 g Platinum crucibles with rim capacity 27 28 ml weight 40 g Platinum molds internal diameter 40 mm heavy construction weight 35 g Snap Cap vials 12 dram Triangular support Retort Stand Meker burner Additional Apparatus for Automated Procedure LECO FX 200 Fluxer Model 601 600 Platinum Gold alloy crucibles grain stabilized 35 mm high x 37 mm ID top x 20 mm ID bottom Platinum Gold alloy casting dishes grain stabi lized 30 mm diameter x 8 mm deep NOTE Because fused beads are prepared using Pt crucibles and molds all samples to be fused must be submitted for carbon and sulphur analysis whether or not these elements are to be reported If samples are found to contain less than 0 3 S the samples can be fused without pretreatment For samples containing 0 3 5 S the samples are roasted before fusion Roasting is carried out by placing 1 500 gofthe sample in a ceramic crucible and heating in a furnace for two hours with the temperature increasing from 800 1200 C The roasted sample is used as indi EA6 8
106. it The scale intervals are approximately equal except that diamond is about 30 times harder than corundum Most minerals have a hardness of less than 7 Minerals with a hardness of up to 2 5 can be scratched with a fingernail hardness of up to 3 can be tested with a copper coin a knife can scratch minerals with hardness of less than 5 5 a porcelain streak plate can scratch minerals with hardness of less than 6 5 a steel file will scratch minerals with hardness of less than 7 Hardness is a measure of the strength of the bonding of the atoms in a crystal and consequently can vary depending on the direction in which it is scratched For example kyanite forms narrow bladed crystals which have a hardness of 4 5 along the axis and 6 7 at right angles to the axis Luster The appearance of the surface of a mineral in reflected light is a quality termed luster On the basis of luster minerals can be divided into metallics and non metal lics Pyrite and galena have a well developed luster Non metallic minerals have luster which can be described in a number of ways e g vitreous resem bling glass greasy as if coated with a thin layer of oil silky resulting from fibrous aggregations of parallel crystals adamantine having a hard brilliant luster pearly resembling mother of pearl resinous resembling resin Colour For many minerals colour is a reliable guide to iden tification In the metallics fresh surfaces
107. mercuric chloride solution A small quantity of white precipitate should appear If no precipitate is observed or if the precipitate is grey the sample should be discarded After 2 3 minutes transfer the reduced solu tion quantitatively to the 600ml beaker con taining 25ml of Zimmerman Reinhardt reagent and 300m1 of distilled water Titrate immediately with KMnO to the first faint pink end point that persists for 15 seconds Do not titrate rapidly at any time Repeat steps 2 1 2 through 2 1 13 with the blank solution Correct the volume of KMnO for the blank titration by subtracting the volume of perman ganate reagent required to titrate the blank from that required to titrate the NBS standard Repeat steps 2 1 1 through 2 1 13 two more times Calculate the average titre Calculate the number of grams of Fe equivalent to 1 ml of KMnO amp gFe _ mi KMnO Fe equivalent Fe Eq Weight NBS Std x Mol Fraction NBS ml KMnO Weight NBS Mol Fraction NBS ml KMnQ 0 20 g 0 6954 22 50 _ 0 20 x 0 6954 Pe Bg 22 5 0 006181 g 3 Decomposition of Samples 3 1 1 3 1 2 Weigh 0 500 g aliquot of homogeneous pow dered sample and transfer to a 30 ml platinum crucible Moisten the sample with a small portion of boiled and cooled distilled water Ferrous Add 15 ml of the decomposition solution and immediately cover the crucible with a tight fitting lid Place the crucible on
108. ml Calculate the selenium content in the rock sample according to the formula 15 ml ng Se g in rock 2 ng Se ml x 02g ng Se ml x 75 ml g uality control The optimum concentration range for selenium is 50 to 300 ng g The determination limit of this method is 20 ppb in rock samples Precision expressed at the 95 confidence limit 20 is 12 relative Accuracy is comparable to the precision based on data collected from standard reference materials Selenium Productivity A technician should be able to complete 20 deter minations per day Additional Notes 1 Avoid digesting the sample to dryness which will result in loss of Se 2 Nitric acid is an essential ingredient for sample digestion 3 Because of the absorbance of Se is much stronger than that of Se Se in the digested sample solu tion mainly in the form of Se must be reduced to Se by hot 8 12M prior to determination 4 1 10 phenanthroline is used as a masking agent to minimize interferences from Cu and Ni 5 Cu and Ni in high concentrations will interfere with the analysis The tolerance limits are 0 3 and 4 0 in rock respectively Bibliography Agemian H and Bedek E 1980 A Semi automated Method for the Determination of Total Arsenic and Selenium in Soils and Sediments Anal Chim Acta Vol 119 pp 323 330 Astrom O 1982 Flow Injection Analysis for the determination of Bismuth by Atomic Absorptio
109. move the torch stand forward up to the interface plate until it reaches the end of its travel Lock it in place using black knobs 1 3 19 Place the ultraviolet shield in place 1 3 20 Check the mass spectrometer vacuum 8 12 x 10 torr and temperature 17 19 K If the gauges do not indicate these values consult the senior technician or Supervisor 1 3 21 Tum on the CEM 1 4 Daily Checkout Routine The operating conditions used for the daily checkout and sample analysis are listed in Table MS2 Lens voltage settings are not fixed Consult with a senior technician or Supervisor if there are any questions on this matter TABLE MS2 ICP MS OPERATING CONDI TIONS Plasma Conditions Torch Extended outer sleeve style RF power 1 5 kW Reflected power 5W Aux flow intermediate 2 2 l min Nebulizerflow 1 0 l min Plasma gas flow outer 16 l min Solution uptake rate 0 85 ml min 1 4 1 Allow the plasma mass spectrometer and detector to warm up for about 20 minutes 1 4 2 Ensure that all instrument operating parameters are set to the values indicated in Table MS2 2 Mass Calibration This procedure must be carried out at the beginning of every work day It updates the mass calibration and tests instrument sensitivity by providing intensity data which can be compared with standard previously acquired data 2 1 1 Enter SPEC DIS The first page of the Spectrum Display program will show up on the screen
110. of Major Elements SiO ALO Fe 0 MgO CaO Flame Atomic Absorption Spectroscopy Determination of Major Elements 102 Al O3 CaO MgO Classical Gravimetric Method Determination of Titanium as TiO Colorimetric Method Determination of Phosphorus P205 Colorimetric Method Determination of Sodium and Potassium Flame Photometric Method Determination of Water Combustion Infrared Absorption Method Determination of Carbon and Sulphur Combustion Infrared Absorption Method Determination of Total Fe Volumetric Titrimetric Method Determination of Ferrous Iron Titrimetric Method Page Header Section Protocols Lee RM eek acts 1 1 Sample Dissolution EA2 1 Graphite Furnace EA3 1 Varian AA775 EA4 1 Liquid Handling System EAS 1 Major RF eee eee EA6 1 Majors XRF EA6 6 Majors XRF llle EA6 14 Majors XRF esee EA6 16 Majors XRF isses se EA6 21 Majors PORE REPE 7 1 Majors Classical sees EA8 1 epe Rite ES EA9 1 Phosphorus llle EA10 1 Sodium Potassium EA11 1 Water pL TERNURA ean eR LS EA12 1 Carbon Sulphur EA13 1 Total Fe E eid REINO 4 1 43 ea er e ee EA15 1 Method Technique Determination of Trace Elements T3 X ray Fluorescence Spectroscopy Appendix A Trace Element Dete
111. of samples for all of the jobs to be reported is stored in the first record of file 1 Refer to the example dialogue included with this report T2FORM The T2FORM program produces the final T2 reports from the secondary corrected concentration EA18 22 data The program will ask for the name of the file that contains the concentration data CON created by the T2CON program the file name for the sample identifiers and the file name for the geologists names and job numbers the two DAT which were created by the JOBFIL program These files should appear on the system disk as a CON file and two DAT files The concentration data are then rounded to the nearest one ppm rock and compared with the method detection limit for each element Any results that are less than the method detection limits are printed as the minus of the method detection limits Results that are greater or equal to one percent are rounded to the nearest decimal with a P percentage appended to them The program will then print out the final concentration file The record number associated with each sample is printed out at the left of the page refer to the example outputs For each job to be reported the program will prompt for the following information 1 The record number associated with the first and last samples in the job 2 Are there any duplicates Traces ICP OES If so then enter the record numbers associated with the first and last duplicates
112. paper and transferring to pulp bags General comments Ensure that the mill is cleaned before and after use with compressed air in the blow out area When com pressed air will not remove the dust use quartzite as a cleaner The grinding area should be kept clean by using the central vacuum unit Apparatus Containers for laying out the samples on the bench top in a systematic fashion Large jaw crusher with steel plates Riffle to split samples Vibratory ring pulverizers equipped with two chrome steel mills a tungsten carbide and ceramic mill can be used if specifically re quested When large quantities of pulp are re quired two large chrome steel mills are available Reagents Quartzite Procedures 1 Samples are collected from the sample reception area along with a series of labels and a list of samples Any special instructions accompanying samples should be clarified with the sample recep tion technician 2 Labels are affixed to bags and or containers used to store crushed rock and final pulp 3 Samplesand bags are placed in previously cleaned containers in ascending order of sample number Any materials affixed to the samples except mark ings are removed 4 Wetsamples are dried in a hot air drier S Theexhaust fan is switched on and the gate to the jaw crusher is opened The jaw crusher is cleaned using compressed air and a wire brush 6 Observing necessary safety precautions the rock
113. place the covered crucible on a hot plate covered with a thermofab cloth at about medium temperature in a fume hood and allow to stand covered for 5 minutes NOTE The ignited silica residue is never pure but always contains small amounts of Fe Al and Ti oxides If the washings were careless it may also contain NaCl Silica from rocks high in Fe and Ti is usually the most impure 3 4 4 Remove the cover with platinum tipped tongs allowing any condensate on the inner surface EA8 4 3 4 5 to drop into the crucible and cautiously heat the outer surface of the cover with a low flame to volatilize condensed HF Evaporate the contents of the crucible to fumes of SO raise the temperature of the hot plate as needed then cautiously evaporate the excess H SO over a low flame holding the open crucible with platinum tipped tongs NOTE Care is necessary to prevent spattering par 3 4 6 3 4 7 3 4 8 3 5 3 5 1 39 2 3 5 3 3 5 4 3 5 5 3 5 6 5537 3 5 8 3 5 9 ticularly if there is much TiO and Zr present When the evolution of SO fumes has ceased heat the crucible to dull redness to decompose the sulphates that are present Cool the crucible and gently wipe the outer surface with a damp cloth to remove adhering sand particles Ignite the covered crucible in an electric fur nace at about 800 C for 5 minutes cool and weigh The difference in weight is that of the pure silica
114. plasma power generator EXPERIENCED TECHNOLOGISTS ONLY Ultraviolet radia tion is emitted by the plasma THE PLASMA SHOULD NEVER BE VIEWED DIRECTLY Even light from the plasma which is reflected from the source housing has a high level of ultraviolet radiation and direct viewing of this light should be avoided If it is necessary to view the unshielded plasma wear fully sealed No 12 welders goggles 4 Theinterlocks protecting the plasma should never be overridden The torch itself can become quite hot and sufficient time should be allowed after extinguishing the plasma before disassembling the torch for routine inspection and cleaning The plasma powertube runs at about 300 C and should be cooled at least 20 minutes prior to shutting the generator down at the end of the day or for inspec tion 5 The exhaust gases from both the plasma compart ment and the generator can be a source of both heat and noxious fumes Both beryllium a vesicant and ozone are emitted from the generator The exhaust from the plasma can contain toxic materials from the samples THEREFORE THE EXHAUST FROM BOTH THE GENERATOR EA19 14 AND THE PLASMA MUST BE VENTED FROM THE ROOM AT ALL TIMES Remember to check the damper positions to ensure that suffi cient exhaust velocity is being maintained 6 Physical hazards can be encountered when moving or working around bottled gases Exercise appropriate caution secure the cylinders use the valve cap
115. prepared by dilution of the custom mixed stock solution with 10 nitric acid Typical concentrations of analytes in working standards range from 0 5 to 8 ppm 2 2 Lithium standards Add 20 ml of 10 000 ppm for every 100 ml of working standard prepared Final concentration of is 2000 ppm Working standards are prepared by serial dilution of the stock lithium solution with 1096 nitric acid 2 3 Chromium standards Add 10 ml of 10 000 ppm for every 100 ml of working standard prepared Final concentration of K is 1000 ppm Working standards are prepared by serial dilution of the stock chromium solution with 10 nitric acid 2 4 Barium standards Add 50 ml of 6000 ppm La K for every 100 ml of working standard prepared Final concentration of La K is 3000 ppm Working standards are prepared by serial dilution of the stock barium solution with 10 nitric acid 3 Sample Decomposition 3 1 Samples are digested with mineral acid using either HNO HCIO HF Procedure 1 or HCI HF HNO Procedure 3 or HNO HF Procedure 5 Details are found in the section on sample dissolution by acid attack 3 2 Samples are decomposed by fusion using lithium metaborate Procedure 1 or sodium Traces AA peroxide Procedure 2 Details are found in the section on sample dissolution by fusion 3 3 Preparation of samples for Barium determina tion Dilute 1 part of sample solution with 1 part of 6000 ppm La K prior
116. priorities for completion are set immediately and updated weekly Elemental analysis is divided into major element analysis and trace element analysis Each has a num ber of packages M1 T1 etc which for convenience group elements according to client requirements or analytical technique A complete description of these analytical packages can be found in the Geoscience Laboratories Analytical Capabilities and Services booklet In addition to the elemental packages an XRF Screen is implemented as an unreported monitor package to check for acid resistant minerals with known acid digestion problems and unusual matrices Selection of Determination Technique In general the instrumental techniques used for each package are M1 M2 M3 XRF alternate techniques include AAS and classical analysis involving gravimetric volumetric and colori metric techniques Tl AAS including flame graphite fur nace and hydride generation techni ques T2 ICP OES T3 XRF T4 T5 ICP MS Screen XRF Selection of Samples to be Monitored with the Screen Program 1 All samples requesting the complete T2 and T4 package or any part of such packages require a Screen evaluation 2 All samples requesting barium and chromium AAS or tin ICP MS require a Screen evalua tion 3 Allsamples requesting major analysis which have a sulphur content 0 3 3 0 should be checked for possible high arsenic using the Screen pro gram Although
117. pulse height distribution PHD Enter 80 to select the upper limit on the window of the pulse height distribution The system will respond with LWL 0 15 lower limit on window of pulse height distribution PHD Enter 15 to select the lower limit on the window of the pulse height distribution In order to assemble a channel typical UPL and LWL values can be assumed Values can be reset after PHD analysis The system will respond with KV MA 0 0 60 50 kV Ma desired Enter 60 50 to specify 60 kV and 50 Ma The system will respond with ANGLE 0 57 470 enter 2 theta angle Enter 57 470 to specify the 2 theta angle The system will respond with OFFS 0 R offset on high angle side Enter R to specify 0 offset on the high angle side The system will respond with OFFS 0 R off set on low angle side Enter R to specify O offset on the low angle side If you wish to subtract background from the peak at angles on either or both sides of the peak the offset values OFFS or OFFS are entered as the number of degrees above or below the peak not the actual 2 theta of the background EA6 17 Majors XRF NOTE Any time the operator wishes to interrupt this or any other routine type a slash followed by a retum R For example when the prompt gives a OFFS and the operator does not want any offsets a R will exit the operator from the ACH routine To change a channel parameter for an element
118. purpose of any sample dissolution technique is to provide a homogeneous solution of the elements of analytical interest The two most common techniques are acid digestion and flux fusion The advantages of acid digestion over fusion include easier operations less total dissolved solids less pos sible introduction of contaminants and adaptability to the use of robotic systems to perform the digestion Its main disadvantage is that some minerals are resistant to acid attack and some elements can be lost in the process Fusion techniques are favored when acid resistant minerals are present and total dissolution is vital The use of fluxes however is likely to introduce con taminants as well as providing a solution with high salt content High salt contents are to be avoided where the sample delivery system can be clogged ICP nebulizer systems A combination of the two techniques can be used for accurate work but the time required makes its less amenable to batch operations In this case acid diges tion is performed on a sample followed by fusion of any residue The solutions are combined to produce a total digestion with minimal salt content A list of the more commonly used acids and fluxes is given below Acids Hydrofluoric Acid 4896 HF w w 29 M is used to attack most silicates HF will attack glass See Safety advisory Perchloric Acid 60 w w 12 M used with HF to decompose silicates and is effec
119. quantity is obtained by subtracting the average of three or more blank values for a run The gold con tent in water is expressed as total soluble Au in ng per liter of water Gold Quality Control The optimum working range is 5 ng 50 ng Au l The determination limit expressed as three times the standard deviation of the reagent blank is 3 ng l The precision at 95 confidence limit 20 at the 10 ng llevelis 2 ng l based on 5 separate measurements carried out on spiked bulk control samples The accuracy is similarto the precision for this method Productivity A technician should be able to complete 18 determina tions per week or about 4 determinations per day Additional Notes 1 To avoid gold contamination glassware such as separatory funnels must be cleaned thoroughly after being used An effective procedure is as follows Fill glassware with cleaning solution and allow to stand overnight Wash with a stream of tap water and rinse with distilled water 2 GFAAS absorbance signals vary from day to day Calibration should be performed on a daily basis 3 MIBK waste is not to be disposed of in the sink It should be collected in a well labelled bottle and the bottle should be tightly covered A profes sional disposal firm will dispose of the bottle 4 Avoid draining the MIBK layer through the stem of the separatory funnel Instead the MIBK por tion should be picked up by a disposable pipette and tran
120. samples wear ear muffs a mask and eye protection 2 The Hiac Royco system works on the basis of laser sizing When removing the laser sizer forcleaning ensure the power is tumed off to avoid accidental exposure to laser radiation MS4 1 vr adin size Anatysts 1 METHOD 1 CONVENTIONAL ASTM D422 72 GRAIN SIZE ANALYSIS Method A conventional grain size analysis involves the fol lowing techniques 1 Sample preparation drying sample and dispers ing clumps 2 Separating the various size fractions sieving and hydrometry 3 Calculating results based on measured weights Apparatus Sieves 2000 850 425 250 125 and 63 microns Soil breaker Sedimentation cylinders 46 cm high 6 4 cm wide Thermometers accurate to 0 5 C Hydrometer ASTM standard hydrometer graduated to read in either specific gravity of the suspension or grams per liter of suspension Jet mixer with electric motor producing 10 000 RPM Reagents Sodium hexametaphosphate deflocculating agent used to break the charge attraction of clay particles A solution of this chemical is made by dissolving 40 g of sodium hexametaphosphate in 1 liter of distilled water Procedure 1 Sample preparation 1 1 The soil sample is collected from the sample reception technician along with a job sheet The sample bag normally of paper construc tion is opened and placed into the drying cupboards for a period of at least one week
121. solution reads 0 120 absorbance Calibration Set 1 00 ppm to read 0 50 Working range 0 5 to 4 0 ppm INTERFERENCES Non atomic species in the air acetylene flame absorb strongly at 232 0 nm background correction is neces sary NOTES 1 To reduce signal noise the gain is reduced by setting working standards to one half values during calibration To obtain the correct con centration value for the samples the readout must be multiplied by 2 before reporting the result 2 A non resonant line for Ni exists at 231 6 nm Make sure the correct wavelength is chosen when the instrument is being peaked 3 Calibrations with 232 0 nm are usually very curved because of a non resonant line of Ni at 232 14 nm This is of particular importance with samples of low Ni content use a 0 5 ppm Ni calibration standard ANALYTICAL CAPABILITIES Determination Limit ppm 5 Precision at the 95 confidence limit 26 at 10X determination limit 50 ppm is 6 ppm absolute EA17 6 Lead Pb STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 217 0 Spectral Band Pass nm 1 0 Background Correction ON Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Pb solution reads 0 060 absorbance Calibration Set 1 00 ppm to read 0
122. the computer on using the I O switch on the left side of the VT240 This will boot the computer into its operational state NOTE the instrument is on booting the computer will activate the vacuum pumps in the spectrometer 2 TheSoftware Starting the Computer The operating files including the RSX 11M operating system are stored on the Winchester hard disk The Baud rate on the terminal is fixed at 9600 NOTE Commands given by the operator are under lined and are followed by a carriage retum When the computer is turned on the following mes sage appears at the printer EA6 1 Majors XRF KDF11B BE ROM V0 8 128KW MEMORY 9 STEP MEMORY TEST STEP 12345678 9 TOTAL MEMORY ERRORS 0 CLOCK ENABLED BOOTING FROM DUO DUO Winchester drive The system continues to transmit messages for some time but these can be ignored by the operator under routine conditions until it prints gt Time and date hr mn dd mmm yy and RETURN 2 1 Enter the time and date in the specified format and push RETURN The system then starts up and requires no input until it requests ABO Task not active Should you mount 201 y n N R DUI disk drive Should you mount DU2 y n 2 2 Enter N as shown above to both of these queries The computer then performs a few more steps in structs the operator how to use the PW1400 software and logs off leaving the system in the general monitor system
123. the platinum crucible with the cake after wiping the bottom of the crucible with wet tissue Tilt the crucible on one side with the glass rod and add approximately 75 ml of distilled water Cover the casserole with a watch glass sup ported by glass triangle and carefully add 20 25 ml of concentrated from a graduated cylinder Set the covered casserole on hot plate Heat on medium setting and gently press the cake with glass rod until the cake loosens and disintegrates At this stage if any unattacked gritty residue is noticed probing with the glass stirring rod the sample should be discarded and the fusion repeated at a higher temperature Remove the platinum crucible using platinum tipped tongs 2 12 Police using a rubber policeman the inside and outside of the crucible to remove adhering particles adding all rinses to the casserole 2 13 Rinse the policeman and glass rod into the casserole 2 14 Set the casserole with watch glass supported by glass triangle on a hot plate covered with thermofab cloth Set the temperature of hot plate between low and medium and evaporate to dryness NOTE On adding to the mixture chlorides of all metals present are formed carbonates are decomposed and silicic acid is formed When alarge amount of the latter is present some of it will precipitate out as white solid On evaporating the contents ofthe dish to dryness the silicic acid present is partially dehydrat
124. the sample in Canada balsam is often suffi cient Loose and crushed grain mounts may be made from unconsolidated sediments and loose minerals The grains are spread on a glass slide and immersed in Canada balsam The mount is covered with a glass slip For crushed grain mounts an immersion liquid capable of supporting the cover slip by capillary ac tion is sufficient Optical Minerology Fine grinding for the production of sections suitable for microprobe analysis is performed on a rotating lap in two stages a cover slip is not applied In the first stage 6 micron diamond paste is used and in the second step 1 micron diamond paste is used 2 Determination of refractive index In a normal thin section it is rare for the contacts between mineral phases to be vertical and for the surfaces to be smooth If there is a difference in refractive index between the mineral and cement the irregularities stepping or curving of the grain margin concentrate or scatter light by reflection and refraction The effect is to give an impression of three dimen sional relief high relief If the difference in refractive index is small the irregularities will hardly be visible and the mineral has low relief Relief may be observed in plane polarised light with a low or medium power objective with the diaphragm nearly closed and with the condenser assembly lowered Description of relief is subjective but can be reference to the refractive i
125. through the instrument software and where the number of permissible correc tions must be minimized in order to be able to accom modate a maximum number of elements Interference coefficients are relatively simple to obtain by the following sequence of steps 1 Calibrate the spectrometer over the element analyte and interferent concentration range of interest using individual element standard solu tions Individual element standard solutions are preferred as mixed element standards can yield in unrecognized interferences in the original calibra tion 2 Nebulize intermediate and high concentration level individual element standard solutions 3 Convert intensity data to concentrations The in terference coefficient may be calculated from the slope of the curve of analyte concentration vs interferent concentration It is possible to use a single high level concentration solution and to estimate the first order interference coefficient from the ratio re Apparent analyte concentration Interferent concentration The use of more than one solution will distinguish between true spectral interferences and back ground contributions For example Interferent Conc Apparent Analyte Conc blank 0 0 ppm V 100 ppm Fe 0 1 ppm V 1000 ppm Fe 0 2 ppm V blank 0 0 ppm Mo 100 ppm Fe 0 1 ppm Mo 1000 ppm Fe 1 0 ppm Mo The use of 100 ppm solely for the determination of an interference coefficient would predict coefficients of 0
126. to 1 ng ml in solution equivalent to 10 100 ppb in rock The determination limit of this method is 5 ppbin rock Precision expressed at the 95 confidence limit 20 is 12 relative The accuracy is comparable to the precision based on data collected from standard reference material Mercury Productivity A technician should be able to complete 15 to 20 determinations per day Additional Notes 1 Standard solutions and reacting reagents should be kept in glass containers Avoid using plastic bot tles since most plastic materials contain mercury compound ingredients as plasticizers and will con taminate the solutions 2 Glassware such as test tubes should be cleaned with nitric acid followed by a rinse with distilled water Soaking overnight in 10 nitric acid is quite effective Glassware known to have been used for samples with high Hg concentrations 71 ppm should be cleaned with conc nitric acid followed by a rinse with tap water and then dis tilled water Tap water usually contains negli gible amounts of Hg It can safely substitute distilled water for cleaning although this is not recommended conventionally 3 Gold platinum palladium arsenic antimony bis muth and selenium are known interferents but are rarely present in concentrations sufficient to cause a significant problems Bibliography Instruction Manual Mercury Monitor elemental mer cury detector 920404 LDC Milton R
127. to determina tion by atomic absorption spectrometry 4 Measurement of Analyte Concentration by Atomic Absorption Spectrometry A Varian 775 is used for the determination of trace elements in solution See Operation of the Atomic Absorption Spectrophotometer Varian AA775 on page EA4 1 in this manual for the steps required to obtain a concentration for each element of interest Consult the information sheets at the end of this section for the instrument parameters and necessary details to perform the determination of each trace element Samples with concentration of the element greaterthan the upper limit of its calibration curve are to be diluted to the appropriate level for remeasurement 5 Calculation of results Calibrate the instrument with the working standard solutions according to the instructions in the operator s manual The spectrometer is constantly adjusted to distilled water zero thus the number obtained from the digital readout is in concentration units usually ppm This reading is converted to a result for the sample by the following R C B x DF where R analyte concentration in the sample concentration measured in solution B reagent blank concentration DF dilution factor from the preparation step For a barium determination a strip recorder is used to obtain a trace of the absorbance of the calibration standards and the sample Peak heights are measured and concentration in solution for t
128. top of the meniscus The temperature of the suspension is checked with a thermometer After the final reading has been taken the sample is transferred to a No 230 62 micron sieve and washed with tap water until the wash water is clear Material left on the sieve is then dried in oven at 110 C This portion is then sieved For clay samples the following sieves are used No 10 20 40 120 and 230 For sands the following sieves are used No 10 14 18 25 35 45 60 80 120 170 and 230 The portion retained on each of the sieves is weighed using a balance and the percentage passing each sieve is recorded Calculations are made using the results from the above procedure 2 Calculation of results For an ASTM hydrometer 152H the calculation reads in grams of soil per liter of suspension 2 Percentage retained on any sieve Weight of soil retained x 100 Total weight of soil 22 Percentage finer than any sieve size 100 Cumulative percentage retained 2 3 Percentage of soil remaining in suspension at the level at which the hydrometer measures the density of the suspension RxA Ww x 100 where R corrected hydrometer reading A correction factor applied to the read ingof hydrometer 152H Refer to Table GSA4 W weight of soil dispersed and used for hydrometry readings g 2 4 Diameter of soil particles mm KE T where K A constant depending on the tem
129. used for geochronology Ta Cs Y Zr Nb Ta La Nd These elements are usually only found at ppb ppm levels in rock samples Several of the world s major economic producers of these elements are located in Canada Tanco Manitoba and Thor Lake NWT Safety advisory The main sources of danger from this method are from X radiation and from electric shock Fire dangerexists as well as potential for eye damage during the sample preparation There is some potential danger associated with the movement of bottled compressed gas For more details refer to the Safety Advisory listed on page EA6 6 Method The method consists of the following techniques 1 Matrix modification by pressing samples into pel lets 2 Irradiation and measurement of characteristic X ray fluorescence using a sequential wavelength dispersive X ray spectrometer 3 Calculation of final results using calibration cur ves stored in the instrument s computer Samples are prepared as pellets in a similar manner to that described in method EA6 Majors XRF General theoretical considerations are presented in Volume I of this manual Apparatus Balance capable of weighing 1 20 g 0 001 g Ring press and die 40 mm Aluminum former sleeve Plexiglass plunger Boric acid measuring vial 25 ml Spex pellet press Model 3624B Reagents Boric acid granular Polyvinyl alcohol 2 w v in distilled water Procedures 1 Pr
130. used to store counts with or without ratioing to a buffer to correct for drift the number should be entered here If the buffer is not used leave MBNR 0 The application of monitor buffers is explained in the software instruction manual INT RATIO NO R INT RATIO internal ratio to the counts appearing at one of the channels measured If ratioing to background the Compton scatter peak or any true internal standard element is required then Y is entered and the system requests identification of the internal standard channels up to three It should be noted that only real channels can be used for internal ratio Off set channels e g Ta or cannot be used MNR 0 1 CPNR calculation program calibration coefficient file Although any number can be used in this file it is probably better to use a CP file of the same number as the LP and the MP DLST 0 MODLST moduli list combination channel results and factors to provide some additional calculation or ratio or a specific application In this example the value is left at the default of 0 CHAN RC IR At this point in the assembly the channels CHAN the rate correction number RC and the intemal ratio standard channel IR are specified Since there can be up to 63 RC factors the ones desired must be chosen carefully For example ELMNT RC IR Ti 1 R ELMNT RC IR P 2 R If an internal ratio were required the channel on which the
131. using graphite furnace atomic ab sorption 4 Calculation of Au Pt and Pd concentrations based on a calibration curve produced from known standard solutions Apparatus Perkin Elmer model 603 atomic absorption spectrophotometer equipped with a model 56 chart recorder HGA 500 graphite furnace and programmer with microcomputer controlled power supply AS 1 auto sampler includes sample table with provision for 30 samples sampling dipper as sembly with separate electronic control unit con taining precision pumps for sampling and rinsing Test tubes borosilicate 10 X 75 mm Aluminum heating block Reagents Matrix acid mixture Nitric acid HNO 1 3 Hydrochloric acid 1 3 1000 ppm Au such as supplied by Fisher Scien tific Company gold chloride in distilled water 100 ppm Au standard solution 10ppm Au standard solution 1000 ppm Pt such as supplied by BDH Chemical 100 ppm Pt standard solution 10 ppm Pt standard solution 1000 ppm Pd such as supplied by BDH Chemi cal EA21 1 Au Pt Pd 100 ppm Pd standard solution 10 ppm Pd standard solution Working Standard Solutions Procedures l Reagent preparation 1 1 Nitric acid 1 3 To a 500 ml volumetric flask containing 200 ml of distilled water add 125 ml of concentrated nitric acid Cool and make to volume with distilled water 1 2 Hydrochloric acid 1 3 To a 500 ml volumetric flask containing
132. will predominate in the acid insoluble residue The amount of residue obtained depends upon the acid used the time and temperature of the digestion and the grain size of the sample The conditions under which the determinations are made should be consistent and well defined Safety advisory 1 The following operations should be performed in a fume hood A Preparation of solution B Addition of the 1 3 solution to the samples C Heating and digesting on a hot plate 2 The MSDS sheet pertaining to the use of hydrochloric acid must be reviewed before proceeding Safety procedures as outlined in the Geoscience Laboratories Safety Manual should also be reviewed Method The method consists of the following techniques 1 Sample decomposition and ignition of residue 2 Direct gravimetric determination of the residue remaining after the weighed sample is digested with hydrochloric acid and the residue ignited 3 Calculation based on the sample weight loss Apparatus Glass beakers 150 ml Hot plate Porcelain crucibles 30 ml with lids Glass filtering funnels Funnelsupports Filter papers Whatman No 40 11 cm Reagents Hydrochloric acid 1 3 Hydrochloric acid 5 95 Procedures 1 Reagent preparation 1 1 1 3 HCI solution Prepare 1 liter of this solution by mixing 250 ml of concentrated HCI with 750 ml of distilled water 1 2 5 95 s
133. with 1 ml of 10 v v HCI and dilute to 100 ml with distilled water A25 2 2 2 1 2 2 2 2 3 1 Working arsenic standard solutions Prepare 0 010 0 020 0 050 and 0 075 ug ml standard solutions by serial dilution of the stock stand ard solution with 10 v v Stock antimony standard solution 1000 ug ml Supplied by Harleco specially prepared from SbCl and standardized for use in atomic ab sorption Working standard solutions Prepare 0 005 0 010 0 020 and 0 030 ug Sb ml standard solutions by serial dilution of the stock stand ard solution with a mixture of 10 sulphuric acid and 20 hydrochloric acid Stock bismuth standard solution 1000 ug ml Dissolve 1 1148 g of Bi O in 20 v v HCI and dilute to 1 liter with the same acid Working standard solutions Prepare 0 001 0 002 0 003 0 005 and 0 010 ug Bi ml stand ard solutions by serial dilution of the stock standard solution with 20 v v 3 Fusion and sample decomposition 3 1 1 3 1 4 3 1 5 3 2 1 3 2 2 For As analysis Weigh out 0 250 g of rock sample and transfer to a 40 ml nickel crucible Add 0 1 g of magnesium oxide and 2 g ap proximately 15 pellets sodium hydroxide and mix the dry contents of the crucible Fuse the sample in a muffle furnace at 550 C for 15 minutes Cool and leach the fusion cake with distilled water Transfer the solution with rinsing to a 100 ml glass bea
134. 00 ergs or energy per gof biological tissue The unit of measure of X ray dose the radiation given off by a radiation source is the roentgen R The unit of biological radiation damage is the REM Radiation Equivalent Man The maximum permissable whole body dose rate is 5 REMs per year or 3 REMs per quarter This is equivalent to 5 Roentgens per year or 100 milliroentgens mR per 40 hour week or 2 5 mR per hour The maximum permissable accumu lated life time whole body dose in roentgens is Majors XRF calculated by subtracting 18 from the workers present age and then multiplying by 5 Body parts have associated maximum dose levels Health and Welfare Canada should be consulted for additional information The spectrometer should be thoroughly monitored with a radiation survey meter when it is installed when it is moved and at routine 6 month intervals The X ray tube head and specimen area should be monitored each time a tube is changed or if the compartment is disturbed All monitoring should be done at a strong spectral line of short wavelength e g Mo The survey meter should be calibrated and sensitive to X ray energies up to 100 KeV Readout should be in mR per hour The meter should not indicate more than 0 5 mR h at 5 cm from any accessible part of the instrument The instrument is equipped with shielding and interlocks which minimize the possibility of con tact with X rays The principal sources of ex posure are
135. 1 100 dilution to be made on the solution prepared by acid diges tion This has the added effect of reducing any concomitants which may cause interferences 3 Before setting the AAS to zero use a clean solu tion of distilled water Change the water frequent ly to avoid a buildup of iron in the rinse solution EA17 10 ANALYTICAL CAPABILITIES Determination Limit ppm 5 Precision at the 95 confidence limit 26 at 10X determination limit 50 ppm is 8 ppm absolute Silver Ag STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 2 5 Wavelength nm 328 1 Spectral Band Pass nm 0 5 Background Correction ON Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Ag solution reads 0 200 absorbance Calibration Set 1 00 ppm to read 1 00 Working range 0 5 to 4 0 ppm NOTES l The higher salt content of the acid digested samples dilution factor 25 may cause viscosity problems and or burner clogging Rinse well be tween samples 2 Assay samples received as chemical leaches must not be diluted with HNO which may cause a precipitate to form Use water for dilutions and determine concentration by flame AAS as soon as possible Normal first dilution is 5 500 ANALYTICAL CAPABILITIES Determination Limit ppm 2 Precision at
136. 1 3 Transfer the solution in the beaker to the 100 ml flask of the original solution 4 1 4 Dilute to 100 ml and use for correcting the absorbance due to the presence of other coloured substances 4 2 Add 10 0 ml of ammonium vanadate solution by pipette to the solution from step 4 1 and mix 4 3 Add 20 0 ml of ammonium molybdate solu tion by pipette and mix 4 4 Mix dilute to volume and mix thoroughly again Allow to stand for 30 minutes 4 5 Measure the absorbance of the yellow colour complex molybdovanadophosphoric acid at 460 nm in a cell against a blank consisting of the reagents and 10 ml of 1 1 HNO already boiled cooled and colourless 4 6 Use the other 50 ml portion of the original solution to correct the absorbance due to the presence of other coloured sustances as ex plained in step 4 1 4 5 Calculation of the results 5 1 To a series of 100 ml volumetric flasks add from a micro burette a series of aliquots of the standard phosphate solution 1 00 mg P O ml to give 0 50 1 00 2 00 and 2 50 mg P504 100 ml 5 2 Add 10 ml of 1 1 HNOs already boiled and colourless 5 3 Dilute to about 50 ml with distilled water 5 4 Add by pipette 10 ml of ammonium vanadate solution and mix 5 5 Then add by pipette 20 ml of ammonium molybdate solution and mix 5 6 Dilute to 100 ml and mix thoroughly Allow to stand for 30 minutes 5 7 Measure the absorbance of the yellow com plex at 4
137. 10 minutes over a Meker burner Then use full heat for 20 30 minutes At no time should the flame envelop the crucible nor should the crucible bottom ever come into contact with the blue cone of the burner flame 2 3 2 4 2 5 Heat the outer surface of the lid with another burner to fuse any particles that may have been spattered on the inner surface of the lid It is good practice to move back the lid grasp the crucible firmly with platinum tipped tongs and swirl it to incorporate any unfused material clinging to the sides of the crucible Remove the crucible cover and carefully place it face up on a clean watch glass Grasp the crucible with platinum tipped tongs remove it from the flame and rotate the crucible as it cools so that the contents solidify around its walls Cool on a marble slab Re heat the crucible with the Meker burner until the inside becomes red but does not melt Cool as before NOTE The second heating helps break away the cake 2 6 2 7 2 8 2 9 2 10 2 11 from the crucible Using a wash bottle direct a jet of distilled water around the top edge of the cake This will usually undermine and loosen it Place the crucible lid in a 250 ml glazed por celain casserole and cover with water Add a few drops of and heat till all adhering particles are dissolved Remove the lid using platinum tipped tongs and a glass rod and rinse into the casserole Carefully transfer
138. 128 The values are doubled if 0 850 g of sample is used Convert percent of CO from calcite to calcite by multiplying by a factor of 2 275 and percent CO from dolomite to dolomite by multiplying by a factor of 2 095 The sum of the carbonates and the ratio of calcite to dolomite are also calculated Quality Control The optimum working range for this method is 5 to 40 total carbonate The determination limit for both calcite and dolomite is approximately 0 5 The precision at mid range is 1 5 at the 95 con fidence level 20 e g 20 1 5 Productivity A technician should be able to complete 25 determina tions per day working on two sets of Chittick apparatus simultaneously Additional Notes 1 The method is simple but lacks accuracy and has poor precision There are many sources of error which cannot be eliminated such as the presence of water vapor in the Chittick apparatus the presence of carbonates other than calcite or dolomite in the sample and the inconsistency of speed of reaction Although the determination limit is expected to be about 0 2 calcite or dolomite equivalent to 1 ml of evolved CO the Laboratories has found that for samples with less than 4 total carbonate the reproducibility of results is poor When one mineral calcite or dolomite predominates the ratio is liable to considerable error even though the determination of the major component may be quite precise If the con
139. 2 International Reference Material 3 In house Reference Material 4 Exit Menu Some or all of these options may be used for a set of data 3 10 The program will display each sample iden tifier and prompt for the proper run identifier Routine sample data should be stored using the four digit run number assigned by the lab job number The program will prompt the operator to place the appropriate data disk in the right hand drive Place the disk in the correct drive When all data has been stored the program returns to the main CONCAL menu Quality Control Precision The CHK2 solution is used for instrument quality control purposes The following table lists the means and associated standard deviations established over a 1 month period n 50 These values are used by the QC functions of the Apple II software EA19 16 TABLE MS5 COMPOSITION OF CHK2 Element Mean Std Dev ug g n 1 Y 18 32 0 479 La 20 535 0 422 Ce 44 164 1 14 Pr 5 013 0 147 Nd 19 347 0 535 Sm 3 962 0 128 Eu 1 121 0 038 Gd 3 629 0 118 Tb 0 552 0 022 Dy 3 447 0 123 Ho 0 703 0 031 Er 2 017 0 089 Tm 0 284 0 018 Yb 1 892 0 075 Lu 0 279 0 016 The instrument check solution was run in batches of international reference materials used in the develop ment of the current ICP MS T4 T5 method Accuracy is assured in two ways 1 by using international reference materials and 2 by matrix effect ex perimentation The mean values established in t
140. 2 1 INPUT 0 0 1 44 0 0 FOR 1 4 1 11 0 0 1 A0CO PRINT A0 1 10 TUBE A B 1 11 HEIGHT 12 ASPIR 0 5 2 13 HEIGHT 70 14 ASPIRO 4000 5 15 RACK CODE 22 2 16 TUBE A B 2 17 HEIGHT 120 18 DISP 0 8005 7 19 RINSE 20 DISP 0 2000 9 21 NEXT B 22 NEXT A 23 HOME A DAHON 4 C P9 r2 NOTES Acomplete explanation of programming can be found in the manufacturer s User s Guide for 221 and 222 Sample Changers The above program uses a 10 ml syringe to give 8 ml of diluted sample 1 AheightofOistakenas the bottom of the test tube Any other height designation is taken as the num ber of millimeters above the bottom of the test tube i e HEIGHT X sends the probe X mm above the the test tube bottom 2 Certain coded racks are programmed to work with a designated vertical arm The Geoscience Laboratories system is equipped with the 123 mm standard length of vertical arm Code 22 racks are designated to hold test tube of 18 mm o d x 150 or 16 x 160 mm and are programmed for use with the long arm needle kit 183 mm At the Geo science Laboratories culture tubes are only 100 mm high and can be used with the 123 mm arm since the movement of the probe is not obstructed by the test tubes Therefore when using racks coded 22 the system assumes you are using the EAS5 1 Liquid Handling System 183 mm arm and will not accept any height value below 60 This value of 60 must be taken as 0 wh
141. 2 L2 CHL3 13 CHL4 L4 1 0 Ti 0 9000 0 0000 0 0000 0 0000 2 0 P 0 9000 0 0000 0 0000 0 0000 3 0 Mg 0 9000 0 0000 0 0000 0 0000 4 0 Na 0 9000 0 0000 0 0000 0 0000 5 0 Mn 0 9000 0 0000 0 0000 0 0000 EA6 23 Majors XRF Internal Ratios and Mass Absorption Corrections To account for mass absorption effects between samples several methods are used i e ratioing of analyte counts to background and Compton scatter peaks For example if the MA of a particular standard reference material is known from major element contribution calculations then the MA of an unknown sample can be approximated as follows if MS Mastandard MU MA unknown sample RS cps at reference peak for standard RU cps at reference peak for unknown sample then MU SARS The net intensity observed at the analyte channel for the unknown sample can be corrected for MA effects by multiplying by a factor i e r IU x MU MS where MaA corrected net intensity IU netobserved intensity This in turn is equal to jis IUxMSxRS _ IUxRS 7 RU Since RS is expected to be constant the MA corrected intensities are expected to be proportional to IU RU where RU can be the counts at either a background position or at the Compton scatter position The latter generally gives the better results NOTE There is a program for Apple Ile comparing the background Compton scatter and major element computations of MA value Application of this progr
142. 25 ml of 50 g l stock solution of sodium hexametaphosphate 14 through 230 mesh 2 Clay separation 2 1 Start with 1000 ml suspension of dispersed solution 2 2 Shake cylinder vigorously forone minute with a stopper over the top 2 3 Let suspension stand for either 6 hours and 3 minutes or 3 hours and 2 minutes and draw off circa 75 100 ml of suspension from depths of 8 cm or 4 cm respectively using a rubber bulb pipette 3 Clay tile preparation 3 1 Let the 100 ml suspension settle for a day or so in a covered jar 3 2 When ready to prepare the tiles carefully decant 90 ml of the clear liquid and stir the remainder to a slurry 3 3 Fill aneye dropper with the slurry and spread it evenly over two glass slides and a porous ceramic tile MS11 1 Cay ANY 3 4 Allow to dry The timing of this preparation should be such that the samples are just dry when the XRD scan is made Late aftemoon is preferable as the tiles can air dry overnight on the bench 3 5 The preparation above will give a sample that has a preferred orientation and with an intense 001 line which is desirable If the full pattern is required a randomly oriented mount will have to be prepared by drying the sample and back packing the sample in an aluminum holder 4 X ray diffraction 4 1 one of the glass slides from 2 to 38 20 using a 1 4 divergence slit 4 2 Place the other glass slide in a desiccator w
143. 3 Background Corrector On On On The following parameters are common for Au Pt and Pd Water Coolant rate 2 5 l min Sample Volume 20 pl Recorder Power Servo Chart Speed 40 mm min Range 5 mv for 0 05 to 0 30 ppm Au and Pd 2 mv for lt 0 05 ppm Au and 0 05 to 0 20 ppm Pd 1 mv for 0 05 to 0 20 ppm Pt and lt 0 05 ppm Pd Graphite furnace program steps A Drying Temperature 120 C Ramp time 10 sec Hold time 25 sec B Charting Temperature 800 C Ramp time 15 sec Hold time 15 sec C Atomization Temperature 2700 C Ramp time sec Hold time 5 sec Enter 5 and press REC key READ key and INT GAS key Must be entered to automatically apply maximum power heating Calibration of the optical tempera ture control is necessary For Pt use 5 sec 5 Calculation of the results The concentrations of gold platinum and palladium in the sample solution are read with the aid of a calibra tion graph The net concentration is obtained by sub tracting the average overall blank value The concentration in the sample is calculated according to the formula CV 1000 where ppbof Au Pt or Pd in rock Au Pt Pd concentration of Au Pt or Pd in g ml in solution Volume in ml of the sample solution usually 2m1 and W weight of sample in grams usually 10 g uality Control The optimum working range for Au is 2 to 40 ppb and 1 to 40 ppb for Pt and Pd in rock T
144. 50 Working range 0 5 to 4 0 ppm INTERFERENCES Few serious interferences have been reported NOTES 1 The 283 3 nm line is sometimes preferred because of its better signal to noise ratio than the 217 0 nm line although the sensitivity is one half 2 To reduce signal noise the gain is reduced by setting working standards to one half values during calibration To obtain the correct con centration value for the samples the readout must be multiplied by 2 before reporting ANALYTICAL CAPABILITIES Determination Limit ppm 10 Precision at the 95 confidence limit 26 at 10X determination limit 100 ppm is 8 ppm absolute Zinc Zn STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 213 9 Spectral Band Pass nm 1 0 Background Correction ON Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Zn solution reads 0 325 absorbance Calibration Set 1 00 ppm to read 1 00 Working range 0 5 to 3 0 ppm INTERFERENCES Non atomic species in the air acetylene flame absorb strongly at 213 7 nm Background correction is neces sary NOTES 1 Calibration curve will bend at ends For samples with low Zn content calibration with a low stand ard 0 5 ppm is necessary 2 Dilute solutions containing more than 3 p
145. 60 0 0000 0 0000 0 0000 10 0 Ga 1 1150 Ta 1111 0 0000 0 0000 11 0 9200 0 0000 0 0000 0 0000 12 0 Nd 1 1105 0 0000 0 0000 0 0000 13 0 La 1 0000 0 0000 0 0000 0 0000 14 0 Nb 9307 0 0000 0 0000 0 0000 16 0 1 1165 0 0000 0 0000 0 0000 17 Nb 9000 0 0000 0 0000 0 0000 16 21 DETERMINATION OF TRACE ELEMENTS Co Cr Cu Ni Pb Zn Ba Li Ag Cd Mn Fe ATOMIC ABSORPTION SPECTROMETRY Traces AA Introduction The trace elements Co Cr Cu Ni Pb Zn Ba Li Mn and Fe can be determined in all geological materials by atomic absorption spectrometry Although man ganese and iron are not considered trace they are determined in samples such as soils and tills known to contain less Mn and Fe than rocks Silver and cadmium are determined on samples digested without acid The average trace element content of various igneous rocks is listed in Table AAS 1 Considerable variations in these values may occur especially with samples which include specific minor accessory minerals which contain these elements as major components The following is a list of minerals containing these trace elements The minerals are significant not only because they can increase the normal expected abun dance in a rock but because many of them are resistant to mineral acid attack and require fusion techniques to provide a complete dissolution Ore grade materials may contain high percentages of these minerals thus p
146. 60 nm for each solution against the Phosphorus solution containing all the reagents with 10 ml colourless 1 1 HNO3 5 8 Prepare a calibration curve using the absorp tion reading on each solution versus con centration 59 The curve should be linear up to 2 5 mg 5 10 The yellow complex is stable for at least one day 5 11 Measure the absorbance of the samples at 460 nm and obtain the concentration of per 100 ml of solution from the calibration curve 1 100 95 P0 mg 05 100 ml x 1000 x a ET The determination limit of this method is 0 02 using a 1 000 g sample The mid range value is 0 596 and an estimate of precision at 95 confidence limits 26 at the mid range value is 0 1 absolute Accuracy is similar to precision for this method Productivity A technician should be able to complete about 10 determinations per day Additional notes 1 Samples high in sulphur should be roasted first in a V ycor brand 30 ml glass crucible in a furnace at 650 C for 3 hours or preferably overnight Then transfer the powder from the crucible to the platinum or teflon dish Rinse the crucible with several portions of water and finally with HNO into the dish 2 Ifthe residue on the filter paper after filtration of the digested sample solution shows white no gritty residue the residue may be titanium phos phate If the residue amounts to more than a few grains it should be ignite
147. 8 16 3 JY48P Digital PDP 11 23 Computer Start up 3 1 3 2 3 3 3 4 3 5 3 6 3 7 Insert JY48P system disk into left system drive SY or DYO and a data disk into the right drive DY1 Boot up the system at the keyboard terminal by typing 173000G and press retum Addi tional information on the computer system is given in the Overview Section page EA18 1 to EA18 13 Enter Date e g 12 Sep 89 and press RETURN Verify the date entered by Y yes or N no Enter the Time 08 32 56 and press RETURN Verify the time entered by Y yes or N no A Dot prompt will appear and that signifies the system is ready 4 Routine Analysis NOTE Ensure that all plasma conditions resistance 4 1 4 2 4 3 4 4 4 5 4 6 settings for all analytes of interest and the parameter settings in the Table are correct At the dot prompt enter R JY48P and press return Enter current position read from slit position dial on the upper part of the JY48P Enter Peak position The JY Main Menu will now appear Enter AN for analysis Enter Table file name in the format of XXXXXX where X represents alphanumeri cal characters A TAB file is created pre viously and has to be on the data disk for execution See Section 7 for Parameter Table set up Enter CHG toensure the analytical parameters are right Changes can be entered at this time 47 Manual Analysis enter ANA
148. AI SD where C observed concentration and CA analyte concentration The intensity contribution and therefore the signal contribution SI due to an interfering element at the analyte wavelength of interest will be directly and EA18 8 linearly dependent on the concentration of the interfer ing element in the sample CI SI a CI b Substitution of this into the concentration expression above results in C CA A1 a CI 1 5 CA x CI y where x and y are defined as Al a and A 1 b the first and zero order interference constants respectively In normal applications only the first order constant is expected to have analytical significance In the case of multiple interferents we can write CA SUM x CI where x and CI represent the individual constants and concentrations of the i interfering elements Correcting Interferences In the analysis of one or more elements and their interferents the number of corrections that may need to be made can potentially be very large Moreover the presence of sequential interferences A interferes on B which in turn interferes on C etc and mutual interferences A interferes on B and B interferes on A will complicate the system It is therefore impor tant to be able to select those interference corrections which will be significant for the determination of any analyte This is especially important in cases where interference correction is done
149. As 14 for Sb and 12 for Bi relative The accuracy for each element is comparable to their respective precisions based on data collected from standard reference materials Productivity A technician should be able to complete 20 samples per day for each element Additional Notes A General comments about all three elements 1 The effect of argon flow rate on absorption signal is significant and the flow rate should not be changed or readjusted in the midst of an analysis Accumulation of deposit of heavy metals in the glass fittings may occur after running a large num ber of samples The fittings can be easily cleaned by pumping 1 v v hydrogen peroxide and 5 EDTA solutions in sequence 3 The impinger filled with concentrated sulphuric acid acts as a gas mixer and moisture absorber It has the effectof homogenizing the gas mixture and hence reducing the signal noise 4 It should be noted that mutual interference effects between the hydride forming elements exist If the concentration ratio of the other hydride form ing element or elements to the analyte is higher than 100 standard addition technique should be employed to ensure correct results The tolerance limits of the hydride forming elements can also be served as a guide line for determining the problem These tolerance limits can be found in the litera A25 4 10 11 13 14 15 16 ture such as some of those quoted in th
150. B is not on Mode menu display 3 ENTER Display the Background menu and select appropriate background for each channel D deuterium arc S H Smith Hieftje A two digit number must be entered one for channel A then one for channel B NOTE If D2 background correction has been selected the CRT will display D2 Warmup for a few seconds NOTE To run S H and D2 simultaneously enter 4 2 which is S H in channel A and D2 in channel B Entering 2 4 is invalid 4 ENTER Select 1 for Conc S E is scale expansion in absorbance mode Select 1 Normal Select default condition 1 1 to display all information con Graphite Furnace centration integration mode and concentration of calibration standards for both channels 5 ENTER To chose statistics Enter no of runs as 3 and ENTER Select 1 to display Mean SD RSD Note Selecting 0 or 1 as the number of runs indicates no statistics and 01 displayed on line 5 of Mode menu 6 ENTER Chose CTF as atomizer if fumace has not been turned on AA units will the 188 will default to the mode last used 7 ENTER Tum autosampler on if required Further description for autosampler PS 75 Prep Station fol lows 9 ENTER Toexit the Mode menu Autosampler with Dilutor This accessory provides automatic sample dilution standard preparation matrix modification and stand ard additions preparations fully under computer con trol via the CRT and keyboard of the Video 22E spectrophotomete
151. B solution replace on hotplate and leave overnight again To the hot dry sample cake add 8 drops of concentrated allow to cool for about 1 minute and then add 1 ml of concentrated HNO and swirl the solution gently Using the plastic dispensing pipette add 4 drops of concentrated HF and swirl the solu tion gently Add approximately 15 ml of deionized dis tilled water and replace the beaker on the hotplate and reduce the volume to about 10 ml THE SOLUTION MUST NOT BE AL LOWED TO GO TO DRYNESS If it does the aliquot must be discarded and the proce dure repeated EA19 2 3 1 9 Remove the beaker from the hotplate and cool to room temperature 3 1 10 If the samples are not going to be transferred within a few hours add about 25 ml 10 HNO 3 1 11 Transfer 1 0 ml of the internal standard solu tion to a clean 100 ml volumetric flask Using 10 HNO transfer the contents of the beaker to this flask and make to mark with 10 HNO 3 1 12 Use Parafilm to stopper the flask and shake thoroughly 3 1 13 Transfer an aliquot of the solution to a 15 ml snap cap polystyrene test tube 3 1 14 The solutions are ready for determination by ICP MS Quality Control The sample digestion procedure is monitored by in cluding reagent blanks and in house reference materials in the batch of client samples Three hotplates are used for the sample digestion Each hotplate can accommodate 20 of the 50 ml Teflon beaker
152. CaCO is dissolved in a mini mum volume of concentrated HNO and then made up to volume with distilled deionized water If work has been done in the vacuum chamber or if anew sampler or skimmer is being used for the first time use appropriate lens optimization proce dures Doherty 1989 If work has been done on the interface plates it is critical that the plates are centered properly on the vacuum port The validity of the Ru Re internal standard scheme depends on this Traces ICP MS 2 Under no circumstances should the deposits on the shadow stop at the base of the skimmer be removed as instrument drift will become uncon trollable It takes about five working days nebuliz ing 1000 ppm Ca almost continuously to build up the required electrically insulating layer 3 The air filters at the base of the RF generator and the filters at the head of the Elan computer end should be cleaned as required about every 2 3 months 4 Themechanical pump oil and alumina balls should be changed about every 5 to 7 weeks 5 Samplers and skimmers should be cleaned at the end of every second work day See senior staff if you have never done this before 6 Empty the slops buckets located behind the Elan every three days Bibliography Doherty W 1989 Spectrochimica Acta Vol 44B page 263 EA19 17 traces ICP MS THE TRACE 5 T5 PACKAGE INDUCTIVELY COUPLED PLASMA SOURCE MASS SPECTROSCOPY Introduction
153. D 550 PRINT PRINT Y N INPUT R 555 IF R N THEN 600 560 PRINT PRINT INPUT PPM BA BA 565 BA BA 1000000 566 BA 76 3 570 PRINT PRINT INPUT PPM FF 571 FF FF 1000000 572 T T FF 3 4 600 T INT T 10000 10000 605 M3 I T Another sample 750 HOME PRINT PRINT DO YOU WANT ANOTHER SAMPLE PRINT Mons o INPUT R 755 IF R Y THEN 405 800 M I Printing sequence 810 PRINT D PR 2 820 PRINT PRINT MASS ABSORBANCE CALCULATIONS 830 PRINT PRINT 840 IF A Y THEN PRINT BKG REFERENCE NS MA MA 850 IF BS Y THEN PRINT COMPTON REF NCS MA MN 860 IF C Y THEN PRINT MAJOR ELEMENT CALCULATIONS INCLUDED 870 PRINT PRINT PRINT 880 PRINT CHRS 27 D CHR 20 CHR 40 CHRS 60 CHRS 0 890 PRINT CHR 9 CHR 3 900 GS CHRS 9 910 PRINT SAMPLE G MA BKG G MA COMP GS MA MAJORS 920 PRINT PRINT 930 FOR I 1 TOM 940 IF A Y AND B Y AND C Y THEN 960 950 GOTO 970 960 PRINT NAS I GSM1 I GS M2 I GSM3 I 970 IF A Y AND BS Y AND C N THEN 990 980 GOTO 1000 990 PRINT NAS I GS M1 I GSM2 I GS 1000 IF AND BS Y AND C Y THEN 1020 1010 GOTO 1030 1020 PRINT NAS I G GSM2 I GSM3 T 1030 IF Y AND BS N AND C Y THEN 1050 1040 GOTO 1060 1050 PRINT NA I GS M1 1 G G M3 I 1060 IF A Y AND
154. DYMNSJ SYS DY1 COPY BOOT DY1 DYMNSJ SYS DY1 Another utility on the operating system disk allows for copying of large numbers of files for example when archiving data files 1 A new disk is formatted and intialized if re quired 2 The command is given R PIP and the system responds with the asterisk cursor 3 The system disk is removed from the LHD and replaced with the disk to be copied or from which files are to be copied The new disk stays in the RHD 4 The instruction is then given DY1 SY or DY1 SY Q Traces ICP OES In the case ofthe former all non system files will be copied in the latter each file will be listed and depending on the Y or R no responses copied or not Once all the files have been copied the operator places the systems disk back into the LHD and types Ctrl C The system exits the PIP routine returning to the system cursor DELETING FILES In order to delete files from any disk the disk name as well as the name and type or appropriate wild card can be used just as in the copy instructions The Q instruction can be used to avoid indiscriminate dele tion Some of the command types are listed below the address is SY but DY1 could also be used DEL SY XXXXXX TYP DEL SY XXXXXX DEL SY XXXXXX Q DEL SY TYP DEL SY TYP Q DEL SY DEL SY Q safer with Q In order to prevent all files from being erased or to remind the oper
155. ES will dilute their fraction 1 1 using the liquid han dling apparatus 2 Adaptation of Procedure 1 to a Robotic System The following is a description of the steps taken by a robotic system to provide a final solution identical to that produced by the manual approach given in 1 above The system requires a weighed sample to be placed at a home position rack number and position The PTFE vessels have a maximum volume of 30 ml can be capped and have dimensions 65 mm height x 29 mm diameter The system can handle 60 samples in two groups of 30 Current programming allows only 48 samples to be processed as one group of 30 and one group of up to 18 2 1 Sample 1 from rack 1 is moved to the dispens ing station and 8 ml of HF 1 ml of HCIO and 2 ml of HNO is automatically added under robotic control to the PTFE vessel 2 2 Sample is placed in position 1 on the low temperature hot block set for 150 C and al lowed to remain there for 3 hours 30 minutes see Note 1 2 3 Sample 2 from rack 1 is processed in the same manner as steps 2 1 and 2 2 24 All samples from rack 1 are treated until the maximum of 30 samples have been placed in the low temperature hot block 2 5 2 6 2 2 8 2 9 2 10 2 11 2 12 2 13 2 14 2 15 Sample Dissolution After sample 1 rack 1 has been in the low temperature hot block for 3 hours 30 minutes the robot will transfer it to position 1 of t
156. ETER OF PARTICLE IN HYDROMETER ANALYSIS 2 50 0 01505 0 01486 0 01467 0 01449 0 01431 0 01414 0 01397 0 01381 0 01365 0 01349 0 01334 0 01319 0 01304 0 01290 0 01276 2 55 0 01481 0 01462 0 01443 0 01425 0 01408 0 01391 0 01374 0 01358 0 01342 0 01327 0 01312 0 01297 0 01283 0 01269 0 01256 2 60 0 01457 0 01439 0 01421 0 01403 0 01386 0 01369 0 01353 0 01337 0 01321 0 01306 0 01291 0 01227 0 01264 0 01249 0 01236 2 65 0 01435 0 01417 0 01399 0 01382 0 01365 0 01348 0 01332 0 01317 0 01301 0 01286 0 01272 0 01258 0 01244 0 01230 0 01217 Specific Gravity of Soil Particles 2 70 0 01414 0 01396 0 01378 0 01361 0 01344 0 01328 0 01312 0 01297 0 01282 0 01267 0 01253 0 01239 0 01225 0 01212 0 01199 2 75 0 01394 0 01376 0 01359 0 01342 0 01325 0 01309 0 01294 0 01279 0 01264 0 01249 0 01235 0 01221 0 01208 0 01195 0 01182 2 80 0 01374 0 01356 0 01339 0 01323 0 01307 0 01391 0 01276 0 01261 0 01246 0 01232 0 01218 0 01204 0 01191 0 01178 0 01165 2 85 0 01356 0 01338 0 01321 0 01305 0 01239 0 01273 0 01258 0 01243 0 01229 0 01215 0 01201 0 01188 0 01175 0 01162 0 01149 Grain size Analysis 1 TABLE GSA3 EFFECTIVE DEPTH BASED ON HYDROMETER AND ON CYLINDER OF SPECIFIED SIZES HYDROMETR 152H Hydrometer Effective Hydrometer Effective Reading L cm Reading L cm 0 16 3 34 10 7 1 16 1 35 10 6 2 16 0 36 10 4
157. Hess H H 1966 Notes on the operation of Frantz Isodynamic magnetic separator Unpubl notes in Frantz manual Hutchison C S Laboratory Handbook of petrographic techniques Wiley New York 1974 527 pages Rosenblum S 1958 Magnetic susceptibilities in the Frantz isodynamic magnetic separator Am Mineralogist 43 pp 170 73 MS7 3 Mineral Identification ROCK AND MINERAL IDENTIFICATION FOR PROSPECTORS AND GEOLOGISTS Introduction The identification of minerals is an essential first step in the classification of rock samples see Vol I Chap ter 15 The initial examination of a rock may be carried out with the naked eye with a hand lens or with a stereo microscope Sufficient information may be obtained at this stage for a preliminary identification which can be confirmed using grain mounts or thin sections in the optical microscope XRD orother more advanced techniques Some of the tests and observations which may be used by the mineralogist in a visual identification are listed here together with other information This informa tion may be incorporated into a report for the geologist or prospector Visual Examination Hardness Oneofthe mostuseful tests in mineralogy is the simple scratch test comparing the ease of leaving a scratch mark on the mineral A series of 10 minerals were used by Mohs to develop a hardness scale in a range of 1 to 10 Each mineral in the scale can be scratched by the one above
158. Interferent Critical C CA Fe 370 Al 45 Ca 330 Mg 85 Ti 55 EA18 12 Consider an ICP OES result at the Nb channel 280000 counts Apparent Nb solution concentration 1 07 ppm Since we do not know the true analyte concentration we assume that it is approximately equal to the ap parent concentration We can therefore estimate ob served C CA values and compare them to the the limiting interferent concentrations Interferent Correction Limiting Observed Fe 370 470 yes Al 45 370 yes Ca 330 370 yes Mg 85 190 yes Ti 55 20 ignore We can examine the effect of ignoring interferences in greater detail For example if we correct the result for all five interferences Nb apparent 1 07 ppm solution Nb corrected 1 07 0 14 0 93 ppm solution The error in ignoring the total matrix contribution would be 15 RSD which is greater than would be allowed by conventional acceptability criteria Ignoring the contribution from Ti alone would result in a concentration of 0 93 0 36 ppm with an error of 0 4 i e less than 1 RSD as predicted by the critical ratio method Similarly ignoring the contribution from Mg Ca Al and Fe would result in errors of 2 5 1 3 9 5 and 1 5 RSD respectively In some cases the observed analyte concentration may not be a suitable approximation of the true analyte concentration and the limiting ratio method will not be suitable to judge the need for a correction Anot
159. L creates a sample identifier file file 1 and a job number with geologist name file file 2 Both files will be stored on the system disk with the file extension DAT files must be deleted if the same filenames are going to be used again The program will process a maximum of 10 jobs and a maximum total number of 150 samples Note Do not delete the TTIO DAT file on the system disk under any circumstances The user is then requested to enter the total number of jobs to be reported This number will be stored in the first record of file 2 Then for each job you will be prompted to enter information in the following order 1 The geologist s name 2 The corresponding job number or date received 3 The corresponding sample identifiers in the order that they will appear on the report form This also corresponds to the order in which they were processed by T2CON If there is a common prefix for the sample identifiers the user is allowed to enter the prefix once prior to the entries of the sample numbers The maximum number of characters allowed for either the prefix or the sample numbers is less than or equal to 5 maximum number of characters for a sample identifier is 10 For example the prefix and the sample number for the sample identifier 87AA A 0001 are 87AAA and 0001 respectively Once the required information has been entered the program allows the user to go back and alter any of the entered information The total number
160. LIZARIN DEAI Flow rates in ml min shown in parentheses Flow diagram of analytical system for fluoride Range 0 2 ug ml Figure F1 EA23 6 Flouride C W LTT MUHI EOS a Jacket of heating bath b Immersion electric heater c Thermometer thermoregulator range 0 200 C d Motor driven stirrer e Plexible Teflon tubing 15ft long coiled on a rigid support f Silicone oil 9 Fractionation column of boro silicate glass h Water jacketed condenser i Distillate collector j Waste lXquid condenser k Air inlet 1 Sample inlet n Sulfuric acid 1 1 inlet c w refers to cold water t v refersto to vacuum Figure F2 Schematic drawing of microdistillation apparatus EA23 7 DETERMINATION OF CHLORIDE Chloride AUTOMATED COLORIMETRIC FLOW INJECTION ANALYSIS METHOD Introduction Chlorine is a strong hydrophile element and as a result concentrations of chlorine reported in rocks and minerals are erratic Chlorine has a larger ionic radius than oxygen and is not easily accommodated in the structure of most oxy minerals It has a similar ionic radius to sulphur but does not readily substitute for sulphur in sulphide minerals Chlorine is precipitated in such minerals as apatite mica amphiboles the sodalite family of minerals in nepheline syenite and related pegmatites and in the scapolite family of minerals in granite pegmatites and contact metasomatic deposit
161. MS for measurement 5 Sample Digestion Requiring the Absence of Hydrochloric Acid HNO HF This procedure is used when hydrochloric acid will prevent the quantitative dissolution of a required analyte It can be completed within 6 hours and is used when silver cadmium and or lead high content are requested The resulting solution is suitable for AAS determination only NOTE Preparation 1 with its longer decomposition time may also be used if step 1 10 is deleted i e HCI addition is eliminated The presence of hydrochloric acid fumes in the vicinity of the decomposing samples will result in low silver results caused by the formation of insoluble silver chloride When cadmium in hydrochloric acid solu tion is taken to dryness losses in cadmium have been observed Lead chloride can form and precipitate if the lead content of the sample is 25000 ppm 5 1 Weigh 1 000 g of sample into a 50 ml PTFE beaker see Note 1 5 2 Add 5 ml of HNO and 5 ml of HF to the beaker see Note 2 CAUTION Be aware of the hazards associated with the use of hydrofluoric acid noted at the begin ning of this section 5 3 After any vigorous reaction has subsided place beaker on a hotplate at 150 C and evaporate to dryness approximately 3 hours 5 4 Add 5 mi of HNO to the dry sample and evaporate to dryness on the hotplate 5 5 Add 3 ml of HNO to the dry residue heat on the hotplate for 1 minute and add 15 ml of distille
162. Page Header Section Sample Preparation 51 1 Assay Preparation TR MS1 2 Whole rock Preparation MS1 4 Carbonate Preparation MS2 1 Conodont Preparation MS3 1 Grain size Analysis MS4 1 Grain size Analysis 1 MS4 2 Grain size Analysis 2 MS4 10 Atterberg coccia es V MS5 1 Heavy Liquid Separation MS6 1 Magnetic Separation MS7 1 Mineral Identification MS8 1 Optical Mineralogy MS9 1 XRD uis tous iD RP VERE ae S M10 1 Clay XRD gabero ete MS11 1 Specific Gravity 24060045 MS12 1 Soil Moisture llle eee MS13 1 Fire ASSQy ved Ee e e MS14 1 Fire Assaysl ease vedas ees swa MS14 2 Fire ASSdyed ducet Mai awk ate PEE MS14 3 tieu waa MS14 4 NOMS uh sp PSU deo MS15 1 Alknorm creona eee ees MS 16 1 ELEMENTAL ANALYSIS SECTION Method Technique Protocols for Sample Digestion and Analytical Determination Sample Dissolution Graphite Furnace Operating System Operation of the Atomic Absorption Spectrometer Liquid Handling System Determination of Major Elements by XRF The Philips PW1400 Fluorescence Spectrometer System Determination of the Major Elements M1 M2 M3 X ray Fluorescence Spectroscopy Appendix A LOI Corrections Appendix B Method Development Appendix C Setting Up an Analytical Package Determination
163. Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu i e the complete T4 package Hf Ta i e part of the TS package Th U Sn Pb and T1 are also included in the T5 package but the HF stabilization technique has not been validated for the determination of these ele ments Rb Cs Nb Zr and Sr The concentrations of these elements are generally determined by XRF as part of T3 package The concentrations of Nb and Sr can also be determined by ICP OES Analysis for these elements by ICP MS is primarily intended for those situations where use of the other two techniques is inappropriate e g small sample sizes efficient use of resources or determination limit requirements The technique below calls for the addition of a small amount of hydrofluoric acid to the final solution This addition keeps traces of Hf Ta Nb and Zr in solution while avoiding the precipitation of the lanthanides as fluorides If analysis for Hf Ta Nb and Zr is not required then it is not necessary to add HF to the final solution Safety advisory 1 Two different acid mixtures are used for sample preparation For safety reasons the composition of each must be recorded on the dispensing bottles 2 Whenusing HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual 3 Nitric acid hydrochloric acid and perchloric acid are corrosive substances Wear protective cloth
164. Preparation of Fused Beads 1 1 1 Weigh the following into a snap cap vial and wearing gloves homogenize 1 500 g 0 001 g 0 887 g 0 001 g 7 326 5 0 001 g rock powder lanthanumoxide tetraborate flux It should be noted that the weights listed above are based on Pure Reagents i e reagents with 0 0 Loss On Ignition The amount of 1 1 10 reagent actually added will depend upon the LOI of the specific reagent batch For ex ample typical weights for the lanthanum oxide and flux are 0 918 and 7 355 respective ly The weights are calculated according to the following formulas j 7 326 x 100 Weight Flux 100 LOI flux Weight La O 0 887 x 100 100 LOI La 0 The final weight of the fused bead should be approximately 9 71 g LOI calculations for samples are presented in Appendix A of this document Transfer the mixture to a platinum crucible and add a small amount of wetting agent Place the crucible in the triangular support on the retort stand and use the Meker bumer to heat on low heat for 3 4 minutes When the iodine fumes have been driven off and the sample begins to melt place the mold on the crucible and increase the heat Periodically during heating remove the mold and stir the contents by swirling using Pt tipped tongs Replace the mold and continue heating When thoroughly molten and mixed pour the melt into the hot molds Swirl the melt gently to cover the
165. RINT PRINT FOR BACKGROUND PRINT PRINT 260 INPUT NAME OF MA REFERENCE NSS 265 INPUT MA VALUE FOR REFERENCE MA 270 INPUT BKG COUNTS FOR REFERENCE BC 280 MA BC For calculation on Compton 300 IF BS Y THEN 309 305 GOTO 350 309 HOME PRINT FOR COMPTON PRINT PRINT Initialization of 100 entries 350 HOME 360 FOR I 1 TO 100 365 NAS I 1 1 0 2 1 0 3 1 0 1 1 0 82 1 0 370 NEXT I 310 INPUT NAME OF MA REFERENCE NCS 315 INPUT MA VALUE OF REFERENCE MN 320 INPUT COMPTON COUNTS FOR REF CC 325 KC MN CC Data Entry 400 I 0 405 I I 1 410 PRINT PRINT INPUT NAME OF SAMPLE NAS I 415 PRINT 420 IF AS N THEN 430 421 PRINT INPUT COUNTS Bi I 425 M1 I KB 1 426 M1 I INT M1 I 10000 10000 EA16 14 Traces XRF 430 IF BS THEN 440 431 PRINT INPUT COMPTON COUNTS B2 TI 435 M2 I KC B2 I 436 M2 I INT M2 I 10000 10000 440 IF C THEN 750 For calculation using the major elements 450 451 0 455 PRINT ENTER THE FOLLOWING CONCENTRATIONS AS PRINT OXIDE 460 PRINT PRINT For each element the operator inputs the oxide concentration as a percentage which is then converted to a weight fraction The MA contribution is calculated from both the analyte and oxygen components For example in lines 465 471 the fraction Si in SiO2 is 0 4675
166. S ENTER Assumes you wish to change the furnace paramenters for the current zero method in RAM This is the method which is in current use or which was used last Modifying Furnace Parameters Modifying Furnace Parameters is reached through op tions 3 4 or 5 of the Recall menu It permits you to alter furnace temperatures ramp times hold times Graphite Furnace purge flow rates and integration time for the develop ment of new fumace methods Once a desired change is requested by typing its ap propriated number from the menu followed by press ing ENTER a new menu will result The change to be made is indicated by The change can be made by typing the desired temperature etc followed by press ing ENTER If no change is to be made at the press ENTER to proceed to the next item in the category to be changed After all stages have been completed the CRT redisplays the modifications Purge flow rates are indicated by the following 0 stop flow 1 low flow 2 medium flow 3 high flow If you wish to introduce air or other auxiliary gas into the cell body during PYR1 type for YES and press ENTER Integration under furnace operation is the time frame during which the absorbance signal is measured by the system microprocessor In most cases integration is set to start at stage 4 Atomization Make sure peak area has been selected for concentration results and statistics to be based on peak area values Integra
167. SY 3 59 7 11 7 8 30 2 63 6 45 MRG 1 39 22 8 51 14 68 13 49 17 9 NBS 1a 14 1 4 16 41 32 2 19 1 63 NBS 88a 1 20 0 19 30 1 21 3 0 28 PCC 1 41 9 0 73 0 53 43 37 8 23 Other CRM s can be substituted for those listed above A complete list of CRM available in the laboratory can be obtained from the Geostandards Coordinator A Varian AA775 is used for the determination of major elements in fluoborate solutions See Operation of the Atomic Absorption Spectrophotometer Varian AA775 on page EA4 1 for details Consult the element specific information sheets for the necessary details to perform the determination of each major element Titanium chromium and barium are possible additional elements which can be determined using sample stock solution A Sensitivity limitations may restrict the usefulness of the range of concentra tion for these elements Trace elements in rocks are generally not sufficiently concentrated in the fluoborate solution for determination by flame AAS 4 Calculation and reporting of results After calibration all readings are in percent oxide of the element Readings are recorded blank corrected and multiplied by the appropriate dilution factor Major 1 and Major 2 Analysis Worksheet forms are to be used for reporting analytical results Results are reported as Percent Oxide Oxide Three sig nificant figures are reported in the range 99 9 to 1 00 two significant figures for 0 99 to 0 01 Less than 0 01 i
168. Sr buffer solution to the flask and make to volume with distilled water 2 11 Retain remainder of stock sample solution A for the determination of MnO NOTES 1 The strontium nitrate should be checked for the presence of major elements as contaminants in particular for calcium In addition a reagent blank should be prepared with each batch of samples Majors AA 2 If the samples are high in sulphur or organic material weighed samples placed in a porcelain crucible should be roasted in a muffle furnace at 650 C for three to four hours or preferably over night 3 For samples known to contain gt 30 iron oxide add about 15 mg of pure graphite powder to the porcelain crucible containing sample and flux This will aid when pouring the fused melt and prevent it from sticking to the bottom of the graphite crucible 4 New graphite crucibles need to be conditioned by placing in a muffle furnace at 1000 C for 15 minutes 5 Itisimportant that after fusion the samples should be stirred until dissolved filtered and made to volume 200 ml on the same day to ensure a faster dissolution of calcium and magnesium fluorides and prevent precipitation of silica 3 Calibration and measurement of analyte The atomic absorption spectrometer is calibrated with in house and certified reference materials prepared as solutions in the same manner as that used for samples Manganese content of geological materials is usually less th
169. T to adjust the markers so that they intersect at the centre of the peak 2 1 15 Press R3 to zoom back to original image size Record the peak position to 2 decimal places 2 1 16 Press and hold the FUNCT key down While this key is depressed press Gn3 twice This should remove the crosshair markers EA19 7 Traces ICP MS 2 1 17 2 1 18 2 1 19 2 1 20 2 1 21 Press G1 to get out of Graphics mode Press Gn3 to stop scanning a bell should sound Press Gn1 to get the Mass Scan Range selec tion screen Repeat the above scan procedure for do Tu Eu Record all four observed masses Press Gnl three times to return to the ECL Commands screen Mass Calibration 24 22 2 1 23 2 1 24 2 1 25 2 1 26 2 1 27 2 1 28 2 1 29 2 1 30 2 1 31 2 1 32 2 1 33 Enter Mcal R Enter REEMCC R Enter m R Press G1 to get to the mass entry screen Enter the observed mass for Y R Enter the observed mass for La R Enter the observed mass for Eu R Enter the observed mass for Lu R Press G3 to obtain print out of the day s mass calibration These are filed for 1 2 months Press 1 to get back to the first screen of mass calibration Press G3 to save the new mass calibration table Press Gnl to get back to the ECL command screen 3 Signal Optimization If the sampler and or skimmer has been removed then the signals must be optimized The oper
170. THESE TERMS GOVERN YOUR USE OF THIS DOCUMENT Your use of this Ontario Geological Survey document the Content is governed by the terms set out on this page Terms of Use By downloading this Content you the User have accepted and have agreed to be bound by the Terms of Use Content This Content is offered by the Province of Ontario s Ministry of Northern Development and Mines MNDM as a public service on an as is basis Recommendations and statements of opinion expressed in the Content are those of the author or authors and are not to be construed as statement of government policy You are solely responsible for your use of the Content You should not rely on the Content for legal advice nor as authoritative in your particular circumstances Users should verify the accuracy and applicability of any Content before acting on it MNDM does not guarantee or make any warranty express or implied that the Content is current accurate complete or reliable MNDM is not responsible for any damage however caused which results directly or indirectly from your use of the Content MNDM assumes no legal liability or responsibility for the Content whatsoever Links to Other Web Sites This Content may contain links to Web sites that are not operated by MNDM Linked Web sites may not be available in French MNDM neither endorses nor assumes any responsibility for the safety accuracy or availability of linked Web sites or the information cont
171. Table MS4 along with the typical determina tion limit optimum range and precision quoted as the 95 Confidence Limit ppm for a value at 10 times the determination limit Safety advisory There are a number of potential safety hazards as sociated with the use of this equipment UN TRAINED OPERATORS MUST NOT USE THE EQUIPMENT The OGS ICP MS has had many modifications and consequently starting procedures are very different from a standard factory delivered instrument TABLE MS4 DETERMINATION LIMITS AND PRECISION FOR THE T4 ELEMENTS Element Determination Optimum Precision Limit Range ppm Y 0 02 0 02 200 0 02 La 0 05 0 05 200 0 05 Ce 0 05 0 05 300 0 05 Pr 0 05 0 05 200 0 05 Nd 0 18 0 18 200 0 18 Sm 0 15 0 15 100 0 15 Eu 0 07 0 07 20 0 07 Gd 0 14 0 14 100 0 14 Tb 0 03 0 03 20 0 03 Dy 0 13 0 13 20 0 13 Ho 0 03 0 03 20 0 03 Er 0 10 0 10 20 0 10 Tm 0 03 0 03 20 0 03 Yb 0 11 0 11 20 0 11 Lu 0 04 0 04 20 0 04 Chondrite plots are automatically included with T4 Data Reports There are five types of hazard associated with this apparatus electrical radiation high temperature noxious gases and physical hazard 1 Electrical hazards can be encountered in three areas the plasma power generator the plasma torch compartment the spectrometer tank com partment Such hazards are also associated with various peripheral equipment like pumps autosamplers and other special apparatus which may be set up to facilitate the ana
172. Trace Form 7 is used to report major and minor elements Mn Fe when they occur at trace levels Assay samples are reported on Form 1117 Assay Work and Report Form Quality control and Additional notes Accuracy In the absence of interfences accuracy may approach precision but is dependent on the quality of the standard solution used Blind duplicate and SRM quality contol data confirm that this method can remain under good analytical control indefinitely This note applies to all of the following information sheets EA17 4 Cobalt Co STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 7 0 Wavelength nm 240 7 Spectral Band Pass nm 0 2 Background Correction ON Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Co solution reads 0 145 absorbance Calibration Set 1 00 ppm to read 0 50 Working range 0 5 to 4 0 ppm INTERFERENCES Minimal interferences have been observed with the air acetylene flame A cobalt response can be depressed in the presence of excess nickel 1500 ppm Either dilute the sample if possible or matrix match the sample and standards NOTES 1 To reduce signal noise the gain is reduced by setting working standards to one half values during calibration The subsequent readout for samples must
173. Traces RF sese EAT16 1 Traces XRF cece nee EA16 4 Traces XRF EA16 7 Traces XRF oc vcl RII EA16 9 Traces XRF oo ees EA16 11 Traces XRF o ive ede EA16 13 Traces XRE ois opel EA16 14 Traces XRF 0 0 loc cc ccna EA16 18 Traces XRF bic ee ee EAI16 19 Traces XRF lessen EA16 20 Traces XRF onega LA VR een EA16 21 Traces SAA o cid EpL es EAI7 1 Traces ICP OES EA18 1 Traces ICP OES EA18 14 Traces ICP OES EA18 21 Traces ICP OES EA18 24 Traces ICP OES EA18 25 Traces ICP OES EA 18 26 Traces ICP MS EAI19 1 Traces ICP MS EA19 5 Traces ICP MS EA19 13 Traces ICP MS EA19 18 Traces NAA cece eee EA20 1 AU PEPA v vu tb 21 1 M 22 1 Flouride eee EA23 1 Method Technique Determination of Chloride Automated Colorimetric Flow Injection Analysis Method Determination of Arsenic Antimony and Bismuth Hybrid Generation Atomic Absorption Spectrometry Determination of Selenium Hybrid AAS Automated Flow Injection Analysis Method Determination of Mercury Cold Vapor Flameless Atomic Absorption Method Determination of Carbonate Carbon CO Coulometric Method Determination of Moisture Determination of Acid Insoluable Residue
174. URE Thermo Jarrell Ash Video 22E CTF 188 Introduction The following procedure is provided as a guide for graphite furnace analysis electrothermal atomization analysis For more specific details refer to the section in the manuafacturer s operation manual concerning each step in the process It is also assumed that the following steps have been taken The atomizer cell has been aligned to allow max imum transmission of the light from the hollow cathode lamp See Section 2 4 page 2 6 A furnace cuvette has been installed see Section 3 6 2 page 3 14 and decontaminated see Section 3 6 4 page 3 17 WARNING Ensure run light on 188 is off and cell body is cool This can be monitored by the temperature displayed digitally on the AA CRT Safety advisory 1 Always ensure that the cell door is functioning correctly before applying power to the atomizer 2 Neverlook directly at a hot furnace cuvette during atomization without proper eye protection welders goggles 3 Nevertouch the cell head i e to change a cuvette assembly while the run light is on or severe tissue burns may result 4 Alwaysensure powerto the 188 control module is off before handling the cell head and allow suffi cient time for all graphite such as the cell door cell body electrode inserts cuvette and as sociated parts cell windows washers and light baffle to cool before handling POWER ON Sequence To avoid communication er
175. W 1400 uses alpha factors to account for and correct inter element effects This requires that the interferent channel be both measured and calibrated The alpha correction uses the concentration of interferent to make the correction This is effective for small interferences Gross interferences caused by direct line overlaps should be accounted for by selecting an alternate line for the interferent running a sample containing a high concentration of interferent and no analyte calculation of net counts at the analyte position calculation of ratio of net analyte CPS to raw CPS atthe interferent channel to obtain the correction factor which is then entered as the L value in the RC set If different measurement programs and link programs see later are stored in the same PB DB combination for varying combinations of a group of elements the same background positions and RC files can be used to build the link programs The RC table for the major elements under DB MAJORS is constructed as follows 90 of the counts observed at the offset position is chosen arbitrarily as the background counts for the five elements concemed To assemble a correction set ARC 1 BKGR R Ti LI 09 CHL2 This must be repeated for each set of correction factors To see a specific entry the instruction PRC is given where is the number desired To see the entire table the instruction PRC is given to get NR BKGR CHLI CHL
176. Yvon JY48P simultaneous ICP source emission spectrometer Meinhard TR 30 C3 nebulizer Traces ICP OES Gilson Minipuls 3 peristaltic pump Gilson autosampler Reagents Argon gas Nitric acid 10 Procedures 1 JY48P Start up 1 1 Tum onthe RF generator A few seconds later a click will be heard and that signifies the cooling water is being turned ON 12 Switch the reflected power switch to OFF 1 3 on the argon gas supply 1 4 Connect the nebulizer tubing to the peristaltic pump and secure peristaltic pump tubing clamps L5 Switch on Plasma Nebulizer and Auxiliary gas flows by depressing buttons marked ac cordingly on the ICP front panel 1 6 Nebulizer water and allow the system to purge argon for two or three minutes 1 7 Set Plasma gas at 14 1pm Nebulizer gas at 0 75 1pm Auxiliary gas at 0 52 1pm Uptake rate of nebulization at 1 ml min pump setting 19 1 8 Switch the nebulizer gas flow off 19 Set tuning control in the front panel to MANUAL and obtain a reading of ap proximately 164 by adjusting with the white buttons at the top left corner 1 10 RESET THE TUNING CONTROL TO AUTO 1 11 Press the RF power button of the torch box ON 1 12 Dial the forward power up to about 1 kW and ignite plasma by briefly pressing the ICP IG NITE button STOP as soon as the plasma has ignited After ignition is achieved immedi EA18 15 Traces ICP
177. ached to the aluminium counting plates with masking tape 2 Avoid irradiating samples which become very hot during long irradiations If the samples are not common silicate rocks then check to ensure that long lived radioisotopes are not produced during irradiation Tantalum ores are an example of samples which become hot 3 Ensure that samples gt 1 in volatile elements such as chlorine are not introduced into the reactor Users must take an official University of Toronto safety course before commencing work and the user must be signed in to the reactor facility in the presence of the supervising staff R G V Hancock Method The method consists of the following techniques 1 Sample preparation bagging and accurate weigh ing of the samples and standards 2 Irradiation of samples placing them into the nuclear reactor for a 16 hour time period 3 Measuring the concentration counting the cooled samples after 7 and 40 days with on line data reduction 4 Calculation of the results based on a comparison of counts from the samples with counts from standards Apparatus Bag sealing unit Slowpoke II nuclear reactor Gamma counter and multichannel analyzer equipped with computer for on line data reduc tion Reagents None required Procedure 1 Sample preparation A wide range of geological samples can be analyzed by neutron activation and there are many different preparation techniq
178. ady prompt put the nebulizer tubing into the first sample tube Wait until the sample has been taken into the plasma and Traces ICP OES allow 20 30 seconds forequilibrium stabiliza tion hit the RETURN key to begin the sample analysis 4 7 5 Whenthe sample analysis is finished transfer the tubing probe to the rinse bottle If the measurement is OK enter Y Otherwise enter N for a not OK answer and the prompt will prompt for REMEASUREMENT Simply hit RETURN and analysis will continue 4 7 6 At each ready prompt repeat the process until all of the samples have been analysed and the prompt ANA CHG END appears 4 7 7 Enter END to end the analysis and return to beginning of JY48P routine 4 8 Use of the Autosampler Enter ANA for sample analysis and include AS in analytical command string a Connect rinse solution tubing to peristaltic pump and secure clamps Enter command string include AS and press return Enter 1 at the prompt samples Hit return at the prompt 1 sample name Enter E to exit at the prompt Ready This will move the light from ACQ to RESET on the upper front panel of the JY48P Check the adjustment of the pipette tube of the autosampler by slowly lowering it into the snap tube with the Auto Adj switch Check both the depth to which the probe reaches in the Snap tube and the centering of the probe as it enters the Snap tube At the base of the autosampler uni
179. ained on them The linked Web sites their operation and content are the responsibility of the person or entity for which they were created or maintained the Owner Both your use of a linked Web site and your right to use or reproduce information or materials from a linked Web site are subject to the terms of use governing that particular Web site Any comments or inquiries regarding a linked Web site must be directed to its Owner Copyright Canadian and international intellectual property laws protect the Content Unless otherwise indicated copyright is held by the Queen s Printer for Ontario It is recommended that reference to the Content be made in the following form Author s last name lt Initials gt year of publication Content title Ontario Geological Survey Content publication series and numbers total number of pages p Use and Reproduction of Content The Content may be used and reproduced only in accordance with applicable intellectual property laws Non commercial use of unsubstantial excerpts of the Content is permitted provided that appropriate credit is given and Crown copyright is acknowledged Any substantial reproduction of the Content or any commercial use of all or part of the Content is prohibited without the prior written permission of MNDM Substantial reproduction includes the reproduction of any illustration or figure such as but not limited to graphs charts and maps Commercial use includes comme
180. al page IV 17 Method The method consists of the following techniques 1 Sample decomposition by acid digestion and residue fusion if necessary 2 Reduction of Fe to Fe by stannous chloride 3 Titration of the sample solution with standardized potassium permanganate solution 4 Calculation of Fe concentration based on Fe present in the net volume after blank subtraction Apparatus Teflon beakers 50 ml Glass beakers 250 ml 600 ml 2000 ml Vycor brand glass crucible 30 ml Filter paper Whatman No 40 12 5 cm Glass funnels 75 mm Glass burette 0 50 ml Glass wool Reagents Hydrochloric acid 36 5 38 Sulphuric acid H SO 96 Phosphoric acid H PO 85 Stannous chloride SnCl 2H O0 Mercuric chloride HgCl Potassium permanganate crystals KMnO Manganese sulphate MnSO 4H O Potassium pyrosulphate K S 0 Hydrofluoric acid HF 48 Procedures 1 Reagent preparation 1 1 Stannous chloride 5 1 2 5 in 10 Dissolve 10 g SnCl 2H O in 10 ml of concentrated Heat to effect the solution for few minutes if necessary EA14 1 Total Fe 1 1 2 1 2 1 3 1 3 2 1 3 3 1 4 1 4 1 1 4 2 1 4 3 1 4 4 1 4 5 Once in solution make to 100 m1 with distilled water The solution should be prepared fresh Mercuric chloride HgCl 5 in H O Dis solve 5 g of HgCl in 100 ml of distilled water Zim
181. ality Control The determination limit for Au is 2 ppb and 1 ppb for Pt and Pd The precision 20 at 20 ppb is 10 ppb for Au and 5 ppb for Pt and Pd MS 14 3 5 Blanks and the MRB 27 standard reference material are processed with every batch of samples for quality control purposes Additional Notes 1 Forsamples withlow concentrations 0 01 oz ton Au Pt or Pd and 0 10 oz ton Ag of precious metals it is preferable to use the dedicated low blank fumace 2 Other assays bullion umpire and fraud case as says these categories of assay although identical to the regular gold and silver assays or special assays require replicate analysis Method 3 Nickel sulphide fire assay Procedure The noble metals are inhomogeneously distributed in rocks and ores forming discrete noble metal minerals and possibly occurring in solid solution in rock form ing minerals chromites and sulphides The nickel sulphide fire assay technique quantitatively collects all the platinum group metals PGE and gold from a large sized sample The bead is dissolved in 12 N HCI the residue is collected on filter paper and irradiated The noble metals on the filter paper can be determined by instrumental neutron activation analysis Full details of apparatus reagents and sample preparation are given in Hoffman et al 1978 3 1 Preparation of charge 3 1 1 Samples are ground following standard pro cedures pa
182. alizarin fluorine blue reagent to develop a colored stream The stream then passes through a flow cell and the absorbance is measured at 620 nm Results appear as peaks Flouride traced on a chart recorder The lag time from sampling to the appearance of a peak on the strip chart is about 3 minutes 5 Calculation of the results The fluoride concentration in the sample solution is read with the aid of a calibration curve subtracting the blank value The fluoride content of the rock sample is calculated in ppm according to the equa tion where ppm of fluoride in rock ug of F ml of the sample solution V volume in ml of sample solution usually 50 ml W weight of sample in grams usually 0 05 g 6 Shutdown 6 1 Place all reagent tubes in distilled water and run water through the system for approximately 10 minutes 6 2 Switch off the sampler when the sample probe is in the water reservoir position 6 3 Switch off the recorder 6 4 Switch off the colorimeter 6 5 Switch off the proportioning pump and lift off the pump platen 6 6 Tur off the vacuum pump 6 7 Tum off the tap water 6 8 Tum off the heating bath 6 9 Lift off sample tray and discard sample solu tions Sample cup can be reused after rinsing with distilled water 6 10 Discard the waste liquid in the liquid trap EA23 3 Flouride 7 Maintenance Cleaning of teflon distillation coil This is ac complished by insertin
183. alpha values to the other CP set This is very useful in that small groups of elements can be calibrated separately and more quickly and new curves be installed in several CP sets The instruction PCP allows the operator to view the full calculation parameter set The instruction ACP assemble calculation parameters can be used to enter manually the D E and alpha values if required To regress on another analyte the operator types NRE next regression element REGR ELMNT To go back to the main program the operator exits from the regression program END and re enters the X14 software MCR X14 It is possible on the MICRO11 computer to run the system from the printer and to leave the graphics terminal in the regression routine It is important to remember however that the same file cannot be open at both terminals There are several re calibration routines available on the PW1400 software The operator is referred to the operator s manual Scanning As a sequential instrument the PW1400 can produce excellent scan results The graphics terminal can be used effectively to enhance scans of regions of interest and produce usable plots at the dedicated printer To obtain a scan with output in both numerical and graphical display it is important to be sure the system is in automatic mode have the sample in the correct measurement position turret assure the data is stored on disk this can be done by typing WDD XXXXXX write
184. also be used to standardize the instrument 5 Anhydrone should be sieved through 8 mesh screen Bibliography Leco RME 100 Instruction Manual 601 300 Leco Instruments 5151 Everest Drive Mississauga Ontario L4W 2R2 phone 416 624 6933 Abbey S 1980 Simultaneous Determination of Water and S in rocks by volatilization and non dispersive Infra red Absorptiometry Can Journal of Spectroscopy V 25 No 5 Potts P Handbook of Silicate Rock Analysis Blackie Glasgow 1987 pp 70 74 Shapiro L Rapid Analysis of Silicate Carbonate and Phosphate rocks Rev Ed USGS Bulletin 1401 1975 pp 54 57 EA12 3 Water Gravimetric Data COMPARISON OF LECO WITH GRAVIMETRIC H20 D um Intercept 039 Slope 952 R Squared 99 n d D 35 ng fee 1 5 2 5 3 5 4 5 Leco Dota Gravimetric Regression EA12 4 Carbon Sulphur DETERMINATION OF CARBON AND SULPHUR COMBUSTION INFRARED ABSORPTION METHOD Introduction In this method the sample undergoes combustion in a stream of oxygen in a LECO induction furnace The absorption of infrared IR radiation by the CO and CO combustion products are measured by separate detectors with the outputs added electronically to yield a result for total carbon The IR absorption of the SO combustion product is measured by a third detector Results are displayed directly on the instrument as C and 5 Sample concentrations a
185. am to results observed for a series of reference materials indicate that MA s obtained using Compton scatter intensities are generally closer to those obtained from major element computations The Compton scatter peak for the rhodium tube is therefore generally defined in the trace element channel sets as Rh and appears in many measurement programs as the internal ratioing element The Link Program The Measurement Program results in the production of intensity count data The Link Program LP links this raw data to correction and calibration parameters in order to correct and convert the counts to concentration units The LP which is stored directly in the Data Bank as opposed to the MP which is stored in the Parameter Bank is generally assigned the same number as the MP from which it receives the data EA6 24 Majors XRF In order to assemble a LP ALP 1 NEW LIST for LP not in memory NRCH 0 5 NRCH refers to the number of channels which are to have count correction applied to them This count correction can be in the form of background substraction internal standardization etc In the example of the creation of the MAJORS package there are 5 channels which will receive offset correction OPTION 0 6 OPTION refers to one of several data options including entry of external data dilution factors analysis totals etc Option 6 gives the analysis total MBNR 0 MBNR Monitor Buffer number If a monitor buffer is
186. ample to dryness which will result in loss of Bi A batch of 40 samples can be digested simul taneously on a hot plate with ease The digested solution should be kept in plastic test tubes 17 Thiosemicarbazide and 1 10 phenanthroline are used as masking agents for Bi to minimize inter ferences from Cu and Ni 18 When the system is ready to run it is a good practice to condition it first by repeatedly analyz ing a standard solution until a constant signal is attained prior to the actual analysis Bibliography Chan C Y and Vijan P N 1978 Semi automated Determination of Antimony in Rocks Analytica Chimica Acta Vol 101 pp 33 43 Chan C Y Baig M W A and Pitts A E 1979 Semi automated Method forthe Determination of Bis muth in Rocks Analytica Chimica Acta Vol 111 pp 169 176 Fernandez F J 1973 Atomic Absorption Determina tion of Gaseous Hydrides Utilizing Sodium As Sb Bi Borohydride Reduction Atomic Absorption Newslet ter Vol 12 No 4 pp 93 97 Kirkbright G F and Taddia M 1978 Analytica Chimica Acta Vol 100 pp 145 Rubeska I and Hlavinkova V 1979 Determination of Arsenic in Rocks and Soils by Atomic Absorption Spectrophotometry using MHS 1 Automated Hydride System Atomic Absorption Newsletter Vol 18 No 1 pp 5 7 Smith A E 1975 Interferences in the Determination of Elements That form Volatile Hydrides with Sodium Borohydride Using Atomic Absorption S
187. amples for this client For each sample the program will ask for the sample identifier that is to appear on the certificate the associated 48 DAT file name and the total radioactivity for the sample Once the client information has been entered the user has the option of producing the worksheet one or two copies the certificate or both The program will prompt the user to change vertical and horizontal pitches on the DEC terminal to 6 and 12 respectively The user is also prompted to line up the print head to the appropriate position and insert carbon paper in the case of the TSPA certificate NOTE If both the worksheet and certificate are required the worksheet is printed first then after changing paper the corresponding certificate is printed EA18 28 SAMPLE Figure ICP1 Schematic Diagram SOURCE SPECTROMETER DETECTOR ELECTRONICS DEC 11 23 COMPUTER FLOPPY DISKS JY48P SOFTWARE GLOGS SOFTWARE Traces ICP OES SIGNAL RAW DATA ANALYTICAL DATA ANALYTICAL REPORTS EA18 29 Traces ICP MS SAMPLE PREPARATION FOR THE T4 AND T5 ICP MS PACKAGES Introduction The ICP MS technique is not well suited to the direct analysis of solid geological samples because wet chemical preparation procedures are preferred to decompose the samples The techniques outlined below are suitable for the determination of the follow ing elements in most rocks Y and the lanthanide elements La Ce
188. amples the time is 24 hours Dilution factor for these solutions is 50 ICP OES will dilute their fraction 1 1 using the liquid han dling apparatus Fast Sample Dissolution for T1 Options by Flame AAS HF HNOj This mixed acid attack requires less time to complete than procedure 1 which uses HCIO It is used for material received and designated as an assay sample which require a faster turn around time and usually fewer elemental determinations with less stringent ac curacy requirements The solution resulting from this procedure is suitable for measurement with atomic absorption only EA2 4 3 1 Weigh 0 500 g of sample into a 50 ml PTFE beaker see Note 1 3 2 Add 5 ml of HCl and 5 ml of HF to the beaker swirling the beaker to ensure complete wetting of the sample see Note 2 3 3 Place the beaker on a hotplate at 150 C and evaporate to dryness approximately 3 hours 3 4 Add 5 ml of HNO to the dry sample and evaporate to dryness 3 5 To the dry residue add 5 ml of HNO and heat on the hot plate for 1 minute 3 6 Add 20 ml of distilled water and using a teflon stirring rod break up the residue to aid in dissolution 3 7 Continue to heat on the hot plate for 15 minutes or until dissolution appears complete 3 8 Examine the beaker for any incompletely decomposed material and note its presence see Note 3 3 9 Cool and transfer the solution to a 50 mi polypropylene centrifuge tube and bring
189. an 2000 ppm If the manganese is to be reported as ppm its determination can be made using pure aqueous standards containing manganese for calibra tion see Traces AA page EA17 1 Table MAASI page EA7 4 serves as a guide for chosing which certified or in house reference materials to use Once prepared these solutions may be stored in polypropylene bottles and used for calibration at a later date NOTE CRM are valuable and should only be used in research work or for programs for certifica tion In house MRB reference materials should be utilized for routine work To calibrate samples which contain greater than 75 SiO silica standards can be prepared using 0 200g pure silica powder to obtain a stock solution of 1000 ppm SiO Prepare a solution as in procedure 2 10 to give a calibration standard equivalent to 100 SiO Smaller volumes of stock solution will produce calibration standards less than 100 i e 45 ml will yield a90 SiO calibration standard Check the silica standards against a few reference materials to ensure consistent results for silica EA7 3 Majors AA TABLE 1 CONCENTRATION OF CERTIFIED REFERENCE MATERIALS To be used for Calibration when Determining Major Elements by AAS CRM SiO Al203 CaO MgO Fe203 GA 69 8 14 5 2 45 0 95 2 86 GH 75 8 12 5 0 65 0 03 1 33 BR 38 5 10 2 13 74 13 28 12 92 DTS 40 6 0 29 0 14 49 75 8 59 Mica Fe 34 4 19 6 0 45 4 65 25 76 SY 2 60 07 12 15 8 03 2 66 6 33
190. and Th Rb Sr Y Zr and Nb This combination of elements is referred to as the Trace 3 T3 package Cs Ga Ta Ce La and Nd can be determined as additions Rb Sr These elements are found in many minerals including micas amphiboles pyroxenes feldspars and less common minerals such as apatite and carbonate minerals One isotope of Rb 87 decays over a geologically useful time interval to 87Sr thus the relative abundance ratio of this pair of isotopes can be used to date rock units Zr Nb Y Rb Ce Ta These elements found in rock forming minerals and accessory minerals are used extensively to characterize the tectonic setting of basalts and granites The processes that control the formation of magma at different regions within the earth also control the relative abundances of these elements thus resulting in characteristic elemental signatures in different areas Th Cs Ga These elements substitute for more abun dant elements in rock or minerals e g Th follows Zr and U Cs follows Rb and Li and Ga substitutes for Al Comparison of trace element major element abundances can be used to track the interplay between formation or alteration process in rock units Ga Al ratios are used to understand unusual granites related to ore deposits Cs is used to characterize fluid magma crystal interaction Th is used either as a petrogenetic discriminator or XRF determinations can pre screen samples high in Zr and Th that will be
191. and proportioning pump and confirm that the analytical system is set up properly 2 Tum on the heating bath It takes about 1 hour to heat up the silicone oil to the preset tempera ture of 165 C Tumoncolorimeter warm up time is 20 min Fillthe sample cups and place them in order on the sample tray Mount the loaded sample tray onto the sampler Engage the pump platen and switch on the proportioning pump with all the reagent tubes dipped in distilled water 6 Tum on the vacuum pump Gently turn on the cold water tap and let the cold water flow steadily through the con densers and drain into the cup sink Switch on the recorder Check the vacuum system and the reagents flow system to ensure no leaks or spills Dis tillate should now fill the collector 4 1 10 Insert the reagent tubes into their correspond ing solutions Figure F1 and establish a base line tracing on the recorder chart 4 1 11 Press POWER push button to on the sampler 4 1 12 The sample is pumped together with 1 1 H SO and air through the teflon coil which is immersed in the heating bath The fluoride in the sample reacts with sulphuric acid in the teflon coil to generate HF and water vapor which distill and condense into the collector while the non volatile solutions including H SO and are separated and drained off under vacuum The distillate is pumped through the resample tube and combined with the
192. and the other K Li These signals are presented in digital form and the resulting readout indicates absolute concentrations of sodium and potas sium expressed in millequivalent per liter Safety advisory When using HF wear glasses and gloves and be ex tremely careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17 When using perchloric acid use fume hood designed for perchloric acid fumes Method The method consists of the following techniques 1 Sample decomposition by acid digestion 2 Simultaneous measurement of Na and K using Flame Photometer type FLM2 3 Calculation of Na and K concentrations based on acalibration curve produced from known standard solutions Apparatus Platinum dishes 50 100 ml Glass funnels 75 mm Filter paper Whatman No 40 12 5 cm Glass volumetric flasks 250 ml Vycor brand glass crucibles 30 ml Polypropylene beakers 5 ml Flame photometertype FLM2 by Bach Simpson Ltd London Ontario Reagents Lithium carbonate Li CO reagent grade Sodium chloride NaCl reagent grade Potassium chloride KCl reagent grade Concentrated hydrochloric acid 36 5 38 Concentrated perchloric acid 60 Concentrated sulphuric acid H5SO 96 Concentrated hydrofluoric acid HF 48 EA11 1 Sodium Potassium Sterox SE non ionic wetting agent for use in Flame Photometer Procedures 1 R
193. antalum is calibrated with an alpha correction for the copper interference As stated above determination limit for tantalum was established to be 10 ppm in the rock sample EA16 10 Traces XRF Measurment program for the Determination of Ce La and Nd The rare earth elements Ce La and Nd are generally determined in conjunction with the T4 package using ICP Mass Spectrometry In certain cases where the concentrations of these elements are expected to be high XRF can be used for the determinations There are two cerium lines in this wavelength region the La 79 01 and the LB at 71 70 2 theta The La line has a barium interference Ba LB 79 26 and is avoided in favour of the Ce Lf line MP13 LP13 and CP13 in the OTHER file are used for the determination Channel conditions and rate correction parameters are outlined below ELEMENT FLT COL DET XTL ORD UPL LWL _ ANGLE OFFS OFFS Ce LB NO F F 1 1 70 30 65 30 71 600 0 70 NdLA NO F F 1 1 60 25 65 30 72 421 0 80 LaLA NO F F 1 1 70 25 65 30 82 865 1 00 Background correction factors are obtained from the intensities observed at the peak and offset positions Ce Nd La In the original procedure reported in earlier manuals for the PW1540 slope in the background was taken into account by calculating the background correction factor as Bf I peak B1 B2 To simplify calculations and as this program is intended only for relatively high concentrations of the
194. aracter Though present even in the most siliceous rocks it is more abundant in the so called basic silicate rocks Chief among its numerous minerals are rutile oc tahedrite anatase ilmenite titanite and pervoskite It is also a component in smaller amounts of many pyroxenes hornblendes biotites garnets and other ferro magnesian minerals and is found in some mag netite and hematite Owing to the refractory nature of some of its com pounds titanium tends to concentrate in the residual products of decomposition of many rocks Typically concentrations in rocks will not exceed 1 percent but may rise to over 5 percent In this method the concentration of titanium is deter mined by measuring the absorbance of the yellow coloured complex formed by titanium with hydrogen peroxide in an acidic solution The measurement is taken by a photometer at wavelength 435 nm This method is used where the sample matrix makes titanium unsuitable for determination by XRF This arises for example when the sulphur content of a rock is too high to allow a fused bead to be prepared for XRF determination This method is applied when TiO content is 3 0 and above the existing XRF calibration range 0 to 3 0 This method is also applied for very accurate deter mination e g where a standard reference material has to be analyzed for certification purposes Safety advisory 1 When using HF wear glasses and gloves and be extremely
195. araju K 1989 1989 Compilation of Working Values and Sample Descriptions for 272 Geostan dards Geostandards Newsletter Vol 13 pp 1 113 Nockolds S Average Chemical Composition of Some Igneous Rocks Bull Geol Soc America Vol 65 Potts P J Handbook of Silicate Rock Analysis Blackie Scotland 1987 622 pages Traces XRF Determination Limits and Precision for Trace Element Analysis Element Additions Ce Cs Ga La Nd Ta Determination Optimum Precision Limit ppm 35 20 10 Range ppm 3 3000 5 1000 5 1000 10 5000 5 1000 5 1000 35 5000 3 3000 5 1000 35 1000 20 5000 10 5000 5 5 5 10 10 10 Precision is quoted in ppm as the 95 percent con fidence limit 26 for values at 10X the determination limit 16 3 Traces XRF APPENDIX A TRACE ELEMENT DETERMINATIONS MEASUREMENT PROGRAMS Measurement Program for the Determination of T3 Elements For this program preliminary corrections found in the RC set include background correction factors and interference factors which are determined independently Corrections and Calibration Background corrections A fused disc of pure silica is used to evaluate background correction parameters These factors are determined from three background points in the scan across the analyte 2 theta angles i e the Y offset Y for Sr Y Zr Rb U and Nb Th for Th and Pb for Pb In order to avoid negative inten
196. are assumed to interfere with the Ta line The resolving power of the PW 1400 X ray spectrometer is high enough to clearly separate the Ta and Ni lines so copper is the only serious interferent in the determination Rate corrections used include 1 the subtraction of Cu intensity due to the spectrometer obtained from a wavelength scan of a quartz blank and 2 background correction MP8 MASK e dT ABS YE CHAN PC Rh 20 OEO Ta 100 OEO Cu 40 OEO 40 OEO In the development of the link program it was observed that the best fit was obtained using Compton scatter MA correction for the Cu and background MA correction for the tantalum line LP8 LPNR 8 NRCH 2 CPNR 8 MODLST 0 MBNR 0 LLNR 0 OPTION 0 INT1 RH INT2 TA2 ELMNT Cu RC 14 15 INTR Ta Rh EA 16 9 Traces XRF Rate corrections observed and stored in the RC table under GEORHO are listed NR BKGR CHL1 CHL2 L2 CHL3 L3 CHL4 L4 14 0 Ta 1 0126 0 0000 0 0000 0 0000 15 40 1 0000 0 0000 0 0000 0 0000 There natural reference materials which have a high certified value for Ta The synthetic glass VSN is used in the calibration of both Cu and Ta concentration values Ta 900 ppm Cu 800 ppm Calibration standards used include TANTALUM SRM Literature Observed ppm ppm VSN 900 900 MAN 310 310 Mica Fe 35 36 COPPER VSN 800 801 MAN 140 132 Mica Fe 4 lt 5 NIM S 19 30 The calculation parameter file indicates that t
197. ariable transformer Tum on the proportioning pump with all the reagent tubes dipped in the water Introduce argon immediately with its flow rate regulated by a flowmeter As soon as the system has stabilized insert the reagent tubes into their corresponding solutions Establish a baseline signal Switch on the automatic sampler The standard sample and blank solutions will then be analysed continuously Record the absorp tion signals on chart paper Measure the peak heights of the standards and draw a calibration graph 5 Calculation of the results The concentration of the element in the sample solu tion is read from the calibration graph Subtract the blank to obtain the net concentration Calculate the content of the element in rock according to the cor responding formula as shown in the following table As Sample wt vol 0 25g 50ml ug g ppm in rock ug ml x 200m1 g Sb Sample wt vol 0 10g 15ml ug g ppm in rock ug ml x 150mi g A25 3 AS 50 BL Bi Sample wt vol 0 10g 15ml ug g ppm in rock ug ml x 150my g Quality Control Optimum working range is 0 01 0 05 ug ml for As 0 005 0 030 ug ml for Sb and 0 002 0 010 ug ml for Bi where no excessive interferences were noted The determination limits expressed as concentrations in rock samples for the three elements are 1 0 ppm for As 0 1 ppm for Sb and 0 05 ppm for Bi The precision for each element expressed at the 95 confidence limit 26 is 10 for
198. arsenic is not determined with the Screen program its presence will be indicated as a high lead value Major Element Analysis 1 A carbon sulphur determination is made on all samples for which any of the major element pack ages are requested 2 If the sulphur content is lt 0 3 proceed with fusion and determination by XRF 3 Ifsulphurcontent is 0 3 3 0 roast the sample prior to fusion Request a Screen evaluation on the sample for arsenic content Proceed with fusion and determination by XRF if the sample contains no appreciable arsenic 4 If sulphur content is gt 3 0 or high arsenic is suggested with the Screen evaluation pass the sample to AAS for preparation and determination Major element analvsis will be performed by AAS when 1 Less than 3 elements per sample are requested 2 Sulphurcontent is 23 096 and or arsenic content is suspected to be high DO NOT attempt to fuse these samples in platinum crucibles Damage to the crucible can occur with some sulphide bearing samples A few hundred ppm As will scour a crucible a few percent will destroy it 3 Silica content is between 10 and 30 percent Protocols Programs for XRF determination in this range are not reliable Iron content is high 25096 as and a glass bead for presentation to an XRF spectrometer is difficult to prepare Selection of Digestion Procedure Acid attack 1 Requests for T1 options and or the T2 package opti
199. asured Safety advisory 1 Ultraviolet radiation is emitted from the mercury lamp when the instrument is on Do not remove the lamp cover while the instrument is on without suitable eye protection Installation of a mercury scrubber at the vent of the cell chamber of the mercury monitor is recommended The scrubber is made of a small tube loosely packed with dry moss sphagnum and a few gold chips It will serve as a mercury trap preventing the hazardous vapor from escaping to the ambient air Method The method consists of the following techniques 1 Sample decomposition 2 Measurement of mercury absorption signal by a LDC Milton Roy Mercury monitor 3 Calculation of mercury concentration based on a calibration curve produced from known standard solutions Apparatus LDC Milton Roy Mercury Monitor Technicon Sampler II Technicon Proportioning Pump Gas liquid separator Drying tube filled with magnesium perchlorate Flowmeter Test tubes Pyrex No 7900 graduated at 25 and 50 ml Hot plate Thermometer Aluminum heating block 2 x 4 x 6 with 12 wells to hoid test tubes and one small well to hold thermometer Vortex Genie mixer Linear strip chart recorder Reagents Thefollowing reagents should be free of mercury and reagent grade Hydrochloric acid 38 such as Ultrapure grade supplied by Baker Chemical Company Nitric acid HNO3 70 Potassium dichroma
200. at the interface between the tube head and the specimen chamber the chamber itself when samples are inserted and removed there could be leakage from a malfunctioning shutter and the analyzer crystal which may be exposed during servicing Leakage is more serious when working at high voltage and current than when working at low energy and intensity levels The primary beam from the tube is very dangerous generating megaroentgens per minute Due to the presence of interlocks the possibility of exposure is extremely low The high potential cable of the instrument from the generator to the tube must be secured at both ends There is still possible danger from high voltage even when the power is off due to the presence of capacitors in the high voltage circuit Operation and maintenance of the instrument should only be carried out by trained technicians It is wise to avoid working in close proximity 1 2 meters to the instrument for long periods of time Eye protection should be worn and appropriate precautions for open flame use should be taken during sample preparations EA6 7 Majors XRF Method The method consists of the following techniques 1 Matrix modification by either fusing or pressing samples into pellets 2 Irradiation and measurement of characteristic X ray fluorescence using a Philips PW1400 wavelength dispersive X ray spectrometer 3 Calculation of final results using calibration cur ves stored
201. ata disk can also be identified by using the Apple II utility program FIXRUNQUE With all this information data can be retrieved as required The reagent blank data for Zr and Hf and the average value used in calculating the results for report ing are hand written on the bench sheets Productivity Sixty samples 2 RBLK 2 digestion check preps and 16 samples per hot plate can be prepared in three days With assistance two batches per week could be prepared if the first batch is started on Monday As sistance during the final transfer step is required if a second batch of samples is to be started on the Wed nesday of the work week Additional Notes 1 Conceming the final steps of the digestion proce dure addition of 8 drops concentrated fol lowed by 1 ml concentrated It is imperative that the HCl be added first Failure to do so will result in irreproducible Hf Ta Nb and Zr analyses and the samples will have to be reprepared from the beginning 2 The gloves have a talcum coating on the inside Wash the outside of the gloves before tranferring samples to avoid getting talcum from inside the gloves in the sample 3 The beakers are cleaned in tap water solution of Sparkleen Rinse this soap solution with hot water Otherwise a thin soap film is left on the beaker 4 The Ru Re dispensing bottle has a screw on cap which connects the bottle with the dispensing device DO NOT SCREW the cap on too ti
202. ating condi tions and measurement parameters are listed in Tables MS2 and MS3 EA19 8 TABLE MS3 MEASUREMENT PARA METERS Measurement mode Sequential 1 point per analyte peak Measurement time 0 5 s point No integrations 6 Resolution 0 9 amu at 10 valley Analyte Mass daltons Oxide isobar int Y 89 Zr 90 Ru 99 La 139 Ce 140 Pr 141 Nd 143 Sm 147 Eu 151 135830 Tb 159 1340 Gd 160 I4 Nqo 190p Dy 163 147 165 149 167 Tm 169 Yb 174 158540 Lu 175 Re 185 This column represents the oxide and isobaric corrections considered significant Other species may be formed but their contributions are con sidered negligible 3 1 1 Ensure the plasma mass spectrometer and detector have warmed up for about 20 minutes 3 1 2 Ensure that all instrument operating parameters are set to the values indicated in Tables MS2 and MS3 3 1 3 Set the Photon Stop and Plate digipots to zero 3 1 4 Set the Einzel and Barrel digipots to 70 and 50 respectively 3 1 5 Select the Mulelem program ECL com mand Select the measurement conditions to monitor the following masses Cd and Os Use 1 2 s point 1 point peak Toggle the isobaric correction for Os off 3 1 6 While monitoring the Os background sig nal increase the Plate digipot setting until just before the background signal starts to rise Monitor the signal while nebulizing a 80 ppb REEA solution If the copper sa
203. ation curve produced from known standard solutions Apparatus A Lachat flow injection analysis system consist ing of A Colorimeter Model 1000 300 B A single valve injection module Model 1600 000 C A sample valve controller Model 1000 150 Technicon Sampler II Technicon Proportioning Pump I with pump tubes required for chloride analysis A flow diagram of the analytical system is shown in Figure C11 Strip chart recorder Graphite crucibles 7 5 ml Teflon beakers 50 ml Test tubes calibrated at 15 ml Reagents Lithium metaborate such as supplied by Spex Industries Cat No L170 Concentrated nitric acid 12 Nitric acid HNO 9 Nitric acid HNO 6 Ferric nitrate solution Fe NO4 9H 0 Mercuric thiocyanate solution Hg SCN EA24 1 Chloride Stock standard solutions Working standard solutions Procedures 1 Reagent preparation 1 1 9 Nitric acid Dilute 90 ml of concentrated nitric acid and make up to 1 liter with distilled water 1 2 6 Nitric acid Dilute 60 ml of concentrated nitric acid and make up to 1 liter with distilled water L3 Ferric nitrate solution 0 5 M In a one liter volumetric flask dissolve 202g of ferric nitrate in approximately 800 ml of distilled water Add 25 ml of concentrated nitric acid and dilute to the mark Mix thoroughly Filter the solu tion if necessary 1 4 Mercuric thiocyanate saturated solut
204. ator what is being erased the system types FILES DELETE SY XXXXXX TY and awaits a Y or R to complete the instruction RECOVERING A DELETED FILE A deleted file can be recovered if and only if no further data have been written to disk since the deletion occurred Type the following commands to recover a file deleted from a disk in the right hand drive R DIR DY 1 Q B O prints out the deleted file infor mation Note the starting block number 76 used as an ex ample for the particular file you are retrieving thus EA18 5 Traces ICP OES B4 RPO 6 10 SEP 84 76 DY 1 Q B prints out deleted file information Note the size 150 used as an example of the file thus DW RAW 150 13 APR 84 104 CRTL C R DUN DY1 FILENAME EXT C START BLOCK NUMBER FILE SIZE The data file should now have been recovered TYPING FILES Files written in ASCII can be viewed in English or the appropriate alphanumerics while the system is in the RT 11 operating system These include such file types as DAT created by the JY48P software and other files often created in the text editing mode e g TXT LST BAK etc The file to be typed must be in the RHD to use the following series of instruc tions to work The instruction is TYPE XXXXXX TYP If there is a long series of related files to be be typed wild cards can be used to avoid unecessary repetition of instructions For example for a long series o
205. aution Do not open bottles or use outside of a well vented hood These liquids are known carcinogens Staff should read the per tinent MSDS sheets 2 Ingestion and contact with skin must be avoided 3 The fumes from these liquids are heavier than air Use down draft hood if possible Procedure 1 Preparing liquids for use Lowering or increasing for sodium polytungstate only the densities of heavy liquids The densities of the first three liquids Table HLS1 can be lowered by diluting with a number of miscible organic solvents including benzene carbon tetrachloride acetone and alcohols Sodium polytungstate is soluble in water at room temperature Solutions should be stored in air tight containers to prevent evaporation of water 2 Recovery or cleaning of organic heavy liquids Depending on the nature of the chemical used to dilute the heavy liquid the organic heavy liquid may be recovered from diluted mixtures by fractional distilla tion at reduced pressure for methyl iodide or simply by evaporation in a vented hood When acetone is used it may be completely removed by streaming water through the diluted heavy liquid until a suitable density marker specific gravity block or mineral fragment placed in the liquid floats The purified liquid is then separated from the excess water and finally dehydrated by shaking with calcium chloride followed by filtration 3 Separation procedure Separations may be ma
206. be used but Cu X rays are the most commonly used falls on a finely ground sample in which the crystallites have a random orientation Dif fraction of the X rays occurs from planes of atoms making up the crystalline lattice The direction in which the diffracted beam travels is dependant on the spacing between successive parallel planes of atoms in the lattice and this is given by the Bragg equation 24910 where d theinterplanar spacing wavelength of the X ray e g 1 542 for CuK 9 angleof incident radiation to the plane of atoms Different planes within the crystal will each give a reflection hkl reflection at a particular angle thus defining a unique diffraction pattern characteristic of that particular crystal somewhat analogous to a fingerprint In a randomly oriented sample all planes giving reflections will be suitably oriented to give a reflection Some minerals tend to have a preferred orientation because of their habit or tendency to break along certain cleavage directions These minerals the most notable of which being the clay minerals and micas will only give a few of the total refections possible Recognition of these minerals can be difficult but usually they have one intense line normally the 001 that can be used to identify them the difficulties arise when two minerals having 001 lines close together are present in the same sample This is often the case in mixtures of clay minerals for which XRD is
207. before stand ardizing Stannous Chloride Dissolve 37 5 g of iron free stannous chloride in 250 ml of 6 N hydro chloric acid This solution should be freshly prepared Mercuric Chloride Dissolve 50 g of mercuric chloride in 1 liter of distilled water Zimmerman Reinhardt Reagent Dissolve 140 g of manganese sulphate in 1 liter of distilled water Cautiously add with stirring 250 ml of con centrated sulphuric acid Cautiously add with stirring 250 ml of phos phoric acid Dilute to 2 liters with boiled and cooled distilled water 2 Standardization of Potassium Permanganate Solution 2 1 1 2 1 10 Weigh 0 200 g of NBS 29a Iron Ore and place in a 250 ml teflon beaker A blank should also be carried through the procedure Add 10 ml of 6 N hydrochloric acid and 10 ml of HF Place on hotplate and evapourate to dryness Add 10 ml concentrated HCI Add 50 ml distilled water Place on hotplate and heat to dissolve Heat the solution nearly to boiling Add stannous chloride solution drop by drop until the yellow colour disappears Add one drop in excess Cool to room temperature Transfer 25 ml of Zimmerman Reinhardt reagent to a clean 600 ml beaker Add 300 ml boiled and cooled distilled water Load buret with unstandardized potassium permanganate solution 2 1 11 2 1 12 2 1 13 2 1 14 2 1 15 2 1 16 2 1 17 2 1 18 Fe Eq e g Rapidly add 10 ml of the
208. by the operator Space allocations are as follows Factory installed methods for ultra pure water 1 to 52 Expansion space for future factory supplied methods for ultra pure water 53 to 69 Factory installed methods for various elements in certain matrices 70 to 129 Expansion space for future factory supplied methods 130 to 149 Storage and retrieval space for operator created furnace methods 150 to 349 These methods are maintained only ifthey are stored through the EA3 6 Store menu The Store menu is self explanatory It will prompt you to store a new method in its appropriate space or to overwrite a similar method that you have created but modified If ENTER is pressed without typing O or 1 the initialization menu will appear without storing the method To store furnace curves CONC must be selected for the results option of the Mode menu It is important to remember that a furnace curve cannot be stored unless the newly developed furnace method it was created for has been stored first Furnace curves must have method numbers in order to be recalled by the microprocessor NOTE Furnace curves are temporary unless stored through this menu Because there is room for only one curve in temporary storage any curve which has not been stored is erased when new curve is created Selection number 3 Store Menu Curve No CTF is offered as a method of storing curves without affliation with a furnace method n
209. careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17 Method The method consists of the following techniques 1 Sample decomposition by acid digestion and fol lowed by residue fusion if necessary 2 Measurement of absorbance by developing colour 3 Calculation of TiO concentration based on a calibration curve produced from known standard solutions Apparatus Platinum dishes 50 ml Vycor brand glass crucibles 30 ml Volumetric flasks 100 ml Glass funnels 75 mm Filter paper Whatman No 42 12 5 cm Burette 0 to 25 ml Baush and Lomb spectronic 501 colorimeter Reagents Hydrochloric acid HCl 36 5 38 Sulphuric acid H2SO 96 Phosphoric acid H PO 85 Hydrofluoric acid HF 4896 Potassium pyrosulphate K S 0 Hydrogen peroxide 30 reagent grade Potassium titanium oxalate KTiO C O 2H 0 Diammonium sulphate NH4 SO Procedures Reagent preparation 1 1 Hydrogen peroxide 3 solution Dilute 10 ml of 30 reagent grade hydrogen peroxide to 100 ml with distilled water Make fresh before use 1 2 1 1 HSO solution Add very carefully 100 ml of concentrated H SO using a graduated cylinder to a 200 ml volumetric flask already containing 75 ml of distilled water and mix Immediately immerse the flask in a 800 ml beaker of cold tap water in order to dissipate the heat generated When cool
210. cated in the following section with ap propriate adjustments made in the weight of flux to counteract the effect of the LOI For samples showing LOI gt 10 the weight of rock powder to be roasted is adjusted prior to roasting such that the weight after ignition is 1 500 g Calculations for LOI correction of sample material are presented in Appendix A Reagents Lithium tetraborate flux anhydrous IMC 99 99 specified LOI lt 1 800 C Lanthanum oxide Baker gt 98 supplied with lot analysis Wetting agent NH4I The lithium tetraborate and lanthanum oxide are pur chased in batches and are identified by the manufacturer s batch number When a new batch is started it is checked in triplicate for LOI and the new blank beads are monitored carefully for contaminants The LOI should be approximately 0 40 for the flux and 1 30 for the lanthanum oxide The weight of reagents used in the sample preparation is adjusted on the basis of the LOI data for these reagents Procedures A complete introduction and detailed description of how to use the Philips PW1400 X ray Fluorescence Spectrometer system is presented on page EA6 1 1 Matrix Modification Samples are prepared for analysis by either pressing into pellets or by fusing the material into glass beads Silicate rock powder samples are fused into glass beads Carbonate rock powder samples are pressed into pellets 11 Silicate Rock Analysis Manual
211. ce Fe to Fe A slight excess is added to ensure complete con version to ferrous iron Sn 2Fe 2Fe Sn EA14 4 The excess Sn2 is removed with the addition of mercuric chloride Hg Cl 2CI White Sn 2HgCl The insoluble mercurous chloride produced will not consume KMnO nor will the mercuric chloride reoxidize Fe Care must be taken not to have a large excess of Sn in solution or an alternate reaction with mer curic chloride occurs Hg Sn 2Cr Black Sn excess Metallic mercury reacts with permanganate to cause a high result A proper reduction is indi cated by the appearance of a white precipitate A grey precipitate indicates the presence of mercury and hence discarding of the sample The total absence of the white precipitate indicates that in sufficient amounts of SnCl was added The Zimmerman Reinhardt reagent is added for the following reasons The manganous ion inhibits the oxidation of the chloride ion by KMnO The chloride oxidation is normally a slow reaction but accelerates it 10CT 2MnO 16H 2Cl 2Mn 8H O The phosphoric acid complexes the Fe produced in the titration and prevents the intense yellow color of the ferric chloride complexes interfering with the end point Phosphate ligands provide good oxygen donors for the ferric ion If the addition of KMnO is too rapid during titra tion
212. cedure A but without HF addition 5 Dilution factor for a 10 g sample is 2 5 for a 20g sample 1 25 Nitric acid concentration is 10 EA2 7 Sample Dissolution Decomposition by Fusion Apparatus Porcelain crucibles Coors High Form 30 ml Graphite crucibles 32x29 mm 30 ml Zirconium crucibles with covers Low Form 25 ml Magnetic stirrers with teflon stirring bars Thermolyne Muffle Furnace Fire and heat retardant mittens Crucible tongs Silicatray Nalgene beakers 250 ml Borosilicate glass beakers 250 ml Filtering funnels Whatman 41 filtering paper 12 5 cm Top loading electronic analytical balance reproducibility 0 001 g Volumetric flasks 100 ml 200 ml Reagents Lithium metaborate anhydrous LiBO Lithium tetraborate anhydrous Li B40 Sodium peroxide granular Na O Nitric acid HNO 69 w w Graphite powder NOTE Use only Na O that is protected by plastic from the metal storage container Procedures 1 Fusion with Lithium Metaborate Lithium Tetraborate Lithium metaborate is a suitable flux for rapidly decomposing silicates and oxygen containing minerals such as spinel chromite ilmenite cas siterite rutile zircon gahnite Zn spinel and other resistant minerals The lithium borate fluxes do not damage platinum ware if oxidizing conditions are maintained and allow the melt to be poured from the crucible either into a platinum
213. centra tion of either mineral is below the determination limit the ratio can only be expressed as gt or lt the value obtained using the limit In calculating the percent of CO from dolomite 4 percent of the difference between the corrected first and second readings is added in order to compensate the CO that is derived from dolomite yet liberated in the initial 30 seconds In analyzing a large number of samples two Chit tick apparati may be operated simultaneously This would increase production substantially Chittick 4 Barometric pressure change is normally very small hence a pressure correction step may be omitted 5 Care must be taken to rinse the decomposition flask thoroughly with water after each analysis since the slightest trace of acid left in the flask will cause some decomposition before the operator has a chance to connect the flask with the rest of the apparatus Moreover the upper part of the flask should be dried after washing to prevent any of the powdered sample adhering to the sides or the neck of the flask Bibliography Official Methods of Analysis of the Association of Official Agricultural Chemists 8th Edition 1955 pp 127 128 and page 947 951 Dreimanis A 1962 Quantitative Gasometric Deter mination of Calcite and Dolomite by Using Chittick Apparatus Journal of Sedimentary Petrology Vol 32 No 3 pp 520 529 EA31 3 arn irs wd ix 20 o E 200 A Decompositio
214. ces ICP MS INDUCTIVELY COUPLED PLASMA SOURCE MASS SPECTROSCOSPY Introduction This suite of elements comprises a geochemically co herent group that has many geological applications Minerals such as apatite zircon monazite and other accessory phases usually concentrate the REE in a sample although these elements can substitute for Ca and Sr in rock forming minerals such as feldspar amphibole or pyroxene The REE are typically reported normalized to a chondritic meteorite com position on a semi log diagram which is automatically included in the T4 data report The REE provide evidence concerning the formation of the solar system the evolution of the crust from the mantle generation of magma within the crust All such data are used in petrogenetic modelling and to understand ore formation and the interplay of fluids of various compositions with pre existing rocks Also the radioactive decay of La and Sm to Ce and Nd respectively over geologically significant time periods can yield further insights into crustal proces ses The speed precision and elemental coverage of the determination of REE abundances by ICP MS is une qualled by any other analytical technique However although isotopic ratios can be determined by ICP MS the precision on the isotopic ratios is not competitive with thermal ionization mass spectrometry TIMS except for screening purposes The Trace 4 T4 package consists of the elements listed in
215. consists of the following techniques 1 Clay preparation 2 Clay separation 3 Clay tile preparation 4 X ray diffraction Procedures 1 Clay preparation for X ray diffractometry Clay preparation is performed from the 230 mesh 63 micron fraction The three pretreatments given below are only used where excessive organic or car bonate content will interfere with the analysis Disper sal ofthe clay minerals should be carried ultrasonically and the use of a deflocculant such as sodium hexametaphosphate should be a last resort 1 1 Add to remove organic colloidal mat ter 1 1 1 Add5mlamounts of 30 H O to a soil water mixture of 1 1 ca 25 g of soil heat lightly and stir occasionally 1 1 2 Add H O until the reaction stops or use light heat ca 80 C for several hours to complete the reaction 1 2 NaOAc buffer or CH COOH removal for carbonates 1 2 1 If there is a large amount of carbonate material add 50 ml of SN NaOAc 1 2 2 Ifthereisasmall amount of carbonate add 25 ml IN and dilute solution to 250 ml 1 2 3 Repeat treatments as necessary 1 2 4 The pH of the solution should be no more acidic than 3 for prolonged periods 1 2 5 This procedure should leave a clear solution within an hour or two with a slurry at the bottom decant this solution 1 3 Treat with sodium hexametaphosphate to dis perse the suspension 1 8 1 Tothe 25 ml soil water suspension add
216. ctable amounts in all sulphide minerals in massive segrega tions contact metasomatic deposits veins pegmatites and in desseminated accessory form in igneous rocks Selenium substitutes for sulphur in these environments and occasionally forms separate selenides of Cu Pb Ag etc In high temperature deposits selenium concentrations can be in the range of 15 to 60 ppm while in medium to low temperature deposits it may occur in the 1 to 5 ppm level The rock sample is digested with a mixture of hydrofluoric nitric and perchloric acids The acidified sample solution is introduced into a carrier stream by a flow injection module in conjunction with an autosampler and a proportioning pump The carrier stream is merged with sodium borohydride solution to bring about a redox reaction between the reductant and the selenium in the sample Selenium is converted to its hydride which is separated ina gas liquid separator and swept by a stream of argon into an electrically heated quartz tube atomizer The atomic absorption of selenium is measured at 196 0 nm The concentration of selenium in the sample solution is read from a calibration graph and the content of selenium in rock is calculated according to the sample weight and total volume of the sample solution Safety advisory 1 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17
217. cticut U S A The AS 1 Automatic Sampling System Revised October 1978 Perkin Elmer Corporaton Norwalk Connecticut U S A EA21 4 Mologhney P E 1980 A fire assay and Wet Chemi cal Method for the Determination of Palladium Platinum Gold and Silver in Ores and Concentrates Talanta Vol 27 No 4 pp 365 367 Van Loon J C 1969 Determination of Platinum Palladium and Gold in a Silver Assay Bead by Atomic Absorption Spectrophotometry Anal Chem Vol 246 pp 122 124 Gold DETERMINATION OF GOLD IN NATURAL WATERS SOLVENT EXTRACTION AND ELECTROTHERMAL ATOMIZATION METHOD Introduction A renewed interest in the search for deposits of gold has been stimulated by recent economic and political events This in turn has led to improvements in the methodologies by which laboratories determine the levels of these elements in geochemical samples The determination of gold in water is based on the method described by McHugh 1984 in which a one liter sample is evaporated to dryness the residue is dissolved in bromine hydrobromic acid gold is ex tracted into methyl isobutyl ketone and determined by graphite furnace atomic absorption spectrophotometry GFAAS The gold content in the MIBK portion or in the 1 liter of water is calculated based on the concentration of gold in MIBK and the volume of MIBK The extrac tion procedure includes back washing with dilute HBr to remove unwanted iron in the MIBK phase
218. cular weight and multiplied by 1000 These figures are added and per centages of each cation iscalculated The cation per Norms centages are then assigned to the normative minerals according to the steps in the norm calculation TABLE NORMI Elemental Approx Elemental Approx Oxide Molecular Oxide with Molecular Weight Cation Weight SiO2 60 102 60 A1203 102 A1l01 5 51 Fe203 160 1 5 80 FeO 72 FeO 72 MgO 40 MgO 40 CaO 56 CaO 56 Na20 62 NaOo s5 31 K20 92 5 47 TiO2 80 TiO2 80 P205 142 2 5 71 32 32 MnO 71 MnO 71 Normative Program Algorithm Alteration of Raw Chemical Data 1 The Fe OyFeO ratio is adjusted according to the equation 96 TiO 1 5 If Fe O is less than this no change is made if it is greater the excess is converted to FeO 2 Thetotal percentage is recalculated to 100 without the volitiles and CQ 3 The cation for MnO is added to that of FeO Algorithm Once the chemical data have been adjusted as indi cated above the program calculates the Norms based on the following steps l Apatite is formed from P and 1 67 times this amount of Ca 2 Pyriteis formed from S and half this amount of Fe 515 1 Norms TABLE NORM2 THE NORM MINERALS Salic Quartz Corundum Orthoclase Albite Anorthosite Leucite Nepheline Kaliophilite Femic Group Wollastonite Enstatite Ferrosilite Acmite Magnetite Hematite Iimenite Apatite Py
219. d 3 mlof nitric acid and using a fine jet of distilled water wash the sides of the beaker about 5 ml 6 8 Heat the beakers on the hotplate and quantita tively transfer the solution to 50 PTFE beakers Wash the pyrex beaker with small portions of distilled water and add the wash ings to the PTFE beaker 6 9 Add 1 ml of perchloric acid to the PTFE beaker and evaporate the contents to dryness using a hotplate set at 180 C CAUTION Note the hazards associated with the use of perchloric acid at the beginning of this sec tion see Note 4 ATTENTION At this time it is necessary to prepare a reagent blank and solutions of certified reference materials SO 1 SO 2 SO 3 and SO 4 using proce dure 1 HF is required with these samples When appreciable siliceous material is present e g inleaves and stems of plant matter hydrofluoric acid may need to be added However these materials also contain a high concentration of calcium and the formation of CaF2 upon addition of HF will deter dissolution and removal of fluoride If HF is to be used add 2 ml to the PTFE beaker at this step 6 10 Remove any acid droplets condensed on the walls of the beakers by gentle tapping of the beaker Sample Dissolution 6 11 Replace the beaker on the hotplate until acid fumes cease 6 12 Check for more droplets and repeat steps 6 10 and 6 11 until all acid has been removed 6 13 Add3mlof HNO to the dry residue and heat on the hotp
220. d in a platinum crucible and fused with 0 5 g of anhydrous Na CO The cake is leached with water and HNO filtered and EA10 3 Phosphorus added to the volumetric flask having the original Bibliography solution Jeffery P G Chemical Methods of Rock Analysis 3 Iron interference is negligible at 460 nm First Edition 1970 507 pages 4 Sample blank absorbance correction is necessary Maxwell J A Rock and Mineral Analysis Wiley in the presence of other coloured substances Interscience Publishers 1968 584 pages Solutions should be white after decomposition Potts P J A Handbook of Silicate Rock Analysis Blackie and Sons Ltd Glasglow 1987 622 pages EA10 4 Sodium Potassium DETERMINATION OF SODIUM AND POTASSIUM FLAME PHOTOMETRIC METHOD Introduction All silicate rocks and minerals contain both sodium and potassium in amounts varying from less than 100 ppm in some ultrabasic rocks such as dunite and peridotite to as much as 10 percent K O or 15 percent in feldspar minerals Rocks containing large amounts of potassium or sodium are rare and most silicate rock specimens contain both alkalies in somewhat similar amounts in the range of 1 6 percent Na O and 0 5 6 0 percent K O Both eiements occur as major constituents of many rock forming minerals particularly the alkali feldspar group and are always determined where a complete chemical analysis of a silicate rock or mineral is re quired
221. d their relative orientations and relations to the crystal faces are diagnostic features of certain mineral phases The extinction angle may be used to document aspects of shape and cleavage The angle between a vibration direction and a cleavage or prominent crystal face is termed the extinction angle If the angle is zero the mineral has straight extinction Extinction angles are particularly useful in the determination of plagioclase determinations 5 Colour and pleochroism Most mineral phases are transparent in thin section but few mineral phases are opaque Colour is judged with the analyzer removed Colour can be a useful property but is rarely diagnostic Opaque minerals are best studied using a microscope fitted for reflected light work Anisotropic minerals frequently display variations in colour or intensity of colour when the stage is rotated in plane polarized light a phenomenon termed pleochroism 6 Point counting to determine the modal mineralogy In order to assess the relative proportions of mineral phases it is often necessary to utilize a polarizing microscope equipped with a point counting stage Such a stage is mounted on the rotating stage and is capable of being moved by a finite and constant dis tance in either direction parallel to the cross hairs of the microscope At each point on the thin section or polished section reflected light microscope the phase is identified visually and the stage i
222. d water 5 6 Heat for an additional 15 minutes or until dissolution is complete 5 7 Cool and transfer the solution to a 50 ml polypropylene centrifuge tube and bring to 25 ml with distilled water EA2 6 5 8 Cover the tube with parafilm or a cap and mix well 5 9 Distribute the samples for AAS determina tion see Note 3 NOTES 1 The weight of sample may be reduced for samples known to contain high lead an appropriate final volume of solution is chosen In these cases the final dilution factor for the solution must be clearly indicated bo The addition of nitric acid may cause a vigorous reaction with the release of large amounts of nitric oxide fumes If the sample is suspected to contain sulphide material moisten the sample with water before adding the nitric acid and cover the beaker with a watch glass after the nitric acid has been added Free sulfur will collect on the surface of the liquid and may remain in the final solution present to the AA spectrometer Care must be taken to avoid nebulizer blockage 3 Dilution factor for these solutions is 25 Nitric acid concentration is 10 12 6 Ashing and Solution Preparation for Vegeta tion Samples This is a two stage technique 1 Dry ashing the vegetation material and 2 Treating the ashed material with mineral acid to obtain a solution for ICP OES determination of the analytes Ashing in a muffle furnace at 500 to 550 C is the technique most
223. data to disk where XXXXXX name of data file Since the scan will likely be near an analyte of interest the operator may want to use the parameters for that element for the scan Thus for example if the scan is in the region corresponding to analyte Cu the operator enters SCH CU The operator then sets the scanning conditions time for counting at each point PTS 1 1 sec initial starting angle SLF 45 slew to 2 theta 45 EA6 29 Majors XRF final angle and scanning increment STS 50 0 05 scan to 50 in 0 05 increments This final instruction will begin the scan If the system is in automatic mode with a WDD instruction the system will write the filename XXXXXX YYY which is to contain the scan information The filename subscript YYY is assigned by the computer As the scan proceeds the numerical intensity value at each point will be listed at the printer terminal as it is obtained If the scan is performed in the manual mode then the only presentation of the scan consists of the numerical output appearing at the printer However if the scan data is stored then the file can be opened and a plot created To open file OPF XXXXXX YYY To plot scan PLS the terminal should be the graphics terminal The system then responds with a series of messages allowing the operator select the mode of presentation as curve or as points as well as a choice of start and end angle The full scale width of the intensity
224. de at any particle size down to a limit of about 10 microns Below 150 microns a centrifuge becomes necessary to accelerate the settling rates of the fine particles The weight of material processed may vary from a few milligrams to 200 300 g The sample must be thoroughly cleaned and free of all clay particles This may be done with the aid of a dispersing agent such as sodium hexametaphosphate or sodium silicate after which the sample is dried and dry sieved to obtain the size of grains required for separation usually 60 120 mesh 3 1 Take a portion of the sample 60 120 mesh and weigh a minimum of 1 g to within 0 01 g MS6 1 Heavy Liquid Separation 3 2 3 3 3 4 3 5 3 6 3 7 3 8 39 MS6 2 Transfer the sample into a glass separating funnel fitted with stopper filled with 200 ml of heavy liquid Gently stir the grains into the liquid to ensure complete wetting Grains with densities greater than the density of the liquid will settle to the bottom of the funnel heavy minerals light minerals will float on the surface of the liquid During the separation stir the grains 3 4 times depending on the quantity of material used Drain the heavy minerals into a filter paper Whatman 4 qualitative Wash the collected minerals 3 or more times with a suitable solvent acetone to remove all trace of heavy liquid Dry the sample in an 110 C oven for 3 5 days Weigh and dry the heavy minera
225. de the range 98 5 101 5 the sample are double checked Possible reasons for poor totals may include disagreement between LOI and total volatiles error in FeO determination error in C S determination errors in sample preparation hightrace element concentrations high fluoride high sulphur high non carbonate carbon content Bias can result from such causes as contamination of standards contamination or degradation of analytical crys tals changesinthe high voltage power supply orother electronic problems detector problems Certified reference materials CRM s or Standard reference materials SRM s covering a wide range of element composition are used for the creation of calibration curves Precision and accuracy are monitored through the use of identified duplicates blind duplicates in house reference materials MRB standards and SRM s EA6 12 TABLE MXRF 5 IN HOUSE GRANODIO RITE REFERENCE MATERIAL Component Mean Precision N 20 SiO2 60 52 0 23 10 Al203 14 83 0 10 10 Fe203 9 03 0 09 10 MgO 2 76 0 16 10 CaO 3 53 0 04 10 Na20 3 27 0 10 10 2 0 77 0 03 10 K20 2 07 0 02 10 P205 0 18 0 02 10 MnO N D N A 10 CO2 0 26 0 01 10 LOI 1 72 0 12 10 A comprehensive series of reference rock samples duplicate analyses blank determinations and calibra tion procedures provide the laboratory with sufficient data to assess both the short term batch and long term multi year p
226. determinate error will deter mine the accuracy of particular determinations The above data support the contention that accuracy can be expected to be within 5 of the true value during routine analysis and at levels significantly above the determination limit Productivity A technician should be able to complete 30 samples per day Additional Notes 1 While analyzing a sample the instrument can store the weights of as many as three samples which are queued for analysis 2 Leave analyzer power on at all times 3 Alarms refer to section P S5 of the manual 1 Water The most common is MGT TIMEOUT which signifies that the analysis has exceeded 800 seconds this is usually due to the presence of high levels of carbonates If this occurs repeat the analysis using V 0 This procedure is similar to the procedure in the absence of vanadium pen toxide except that powder is placed on top of the rock powder A vanadium pentoxide blank should be carried through the analysis and the value obtained should be subtracted from the sample results NOTE Do not reuse nickel crucibles if was employed The reuse of these crucibles reduces the life of the combustion tube 4 The RMC 100 can be calibrated using the stand ards supplied by Leco Ca OH and CaC O which contain 24 0 and 12 2 respectively H 0 In house reference rocks MRB 10 7 14 which contain 11 7 2 31 2 77 2 31 respectively H O can
227. direct viewing of this light should be avoided 3 The plasma operates at extremely high tempera tures The interlocks protecting the plasma should never be overridden The torch itself can become quite hot and sufficient time should be allowed after extinguishing the plasma before disassem bling the torch for routine inspection and cleaning The plasma power tube runs at about 300 C and should be cooled at least 20 minutes prior to shut ting the generator down at the end of the day or for inspection 4 The exhaust gases from both the plasma compart ment and the generator can be a source of both heat and noxious fumes Both beryllium and ozone are emitted from the generator The exhaust from the plasma can contain toxic materials from the samples THE EXHAUST FROM BOTH THE GENERATOR AND THE PLASMA MUST BE VENTED FROM THE ROOM AT ALL TIMES Remember to check the damper posi tions to ensure that sufficient exhaust velocity is being maintained 5 Physical hazards can be encountered when moving or working around bottled gases Exercise appropriate caution secure the cylinders use the valve caps use properly designed carts to move the cylinders and use appropriate footwear Method The method consists of the following techniques l Dissolution of sample using acid digestion techni que 2 Measurement of analyte concentration using the Jobin Yvon JY48P ICP OES instrument 3 Calculation of results Apparatus Jobin
228. ducing a releasing agent such as strontium and by matching sample and standard solu tions to obviate combined interference effects The slight ionization interference which occurs with the air acetylene flame is controlled with the added strontium A nitrous oxide acetylene flame causes severe ioniza tion of calcium The addition of a readily ionizable substance will overcome this effect NOTES 1 The depression of calcium signals air acetylene flame is caused by elements which give rise to stable oxysalts 2 The presense of a cyanogen emission band at 421 5 nm may cause an increase in background noise if not completely separated by the monochromator 3 The formation of oxysalts is virtually eliminated with the use of a nitrous oxide acetylene flame To control the resulting ionization of calcium with this flame 0 2 potassium salt should be added to both samples and standards 4 Noiselevel wasobserved to be excessive when the nitrous oxide acetylene flame was used and the air acetylene flame is preferred MagnesiumOxide MgO STANDARD SOLUTIONS Use certified reference materials prepared in the same manner as the samples INSTRUMENT PARAMETERS Lamp Current ma 3 5 Wavelength nm 285 2 Spectral Band Pass nm 0 5 Flame Description Nitrous oxide acetylene Fuel lean Air acetylene Oxidizing fuel lean blue INTERFERENCES Interferences are similar to those which occur with calcium i e silicon alumin
229. e tween the terminals the following steps are required 2 5 At the printer type ASP assemble system parameters There are only two items of in terest in the system parameters the terminal type and whether or not the spectrometer is connected The first line will read TERMINAL TYPE PR e waiting for input 2 6 Since the terminal is a printer and this is the default device simply press retum If the required terminal type is a graphics terminal simply enter GT 2 7 Continue depressing the retum key until the following message appears SPECTROMETER CONNECTED Y N 2 8 Exit the ASP routine by pressing R 2 9 Check the status by typing PSP If the status is Not correct repeat steps 2 5 to 2 8 2 10 Exit from the program by typing END The cursor will return 2 11 After getting the cursor type MCR X14 or X14 This will initiate the PW 1400 software The ASP program can be used to change the terminal type PR or GT at any time The system can be run entirely through the video terminal The screen dump printer LASO can be used to obtain print out of results PON printer on The printer can be turned on via a switch on the left side 3 Running the Samples Once the Measurement Program MP Link Program LP Rate Correction Set RC and the Calculation Parameter CP Sets have been defined it is possible to run samples on a routine basis The development of these programs is described
230. e determined by XRF This will arise for example when the sulphur or iron content of the rock is too high to allow a fused bead to be prepared for XRF deter mination This method is also applied when the silica content is between 10 and 30 percent and existing programs for determination by XRF in this range are unsuitable Silicon Silicon is the second most abundant element in the lithosphere after oxygen The simplest clas sification of silicate rocks is based upon silica content 5102 which is normally in the range of 35 to 80 percent Quartzites and sandstones may contain 90 to 95 percent silica The carbonate rocks are a large and varied group of igneous carbonatite sedimentary and metamorphic rocks with silica content ranging from percent calcite and certain marbles to 30 percent in some sediments and carbonatites Silica occurs in crystalline forms quartz tridymite crystoblite and in the amorphous state opal onyx chalcedony More commonly silica combines with magnesium iron aluminium alkali and alkaline earth elements to form complex silicate minerals These include rock forming minerals such as olivine pyroxenes amphiboles micas feldspars feldspathoids e g nepheline leucite sodalite and aluminosilicates kyanite kaolin sillimanite Other minerals such as zircon tourmaline and sphene also contain silica Aluminium Aluminium follows silicon as the third most abundant element in the eart
231. e Ascarite and Anhydrone in the oxygen inlet tube should be replaced weekly or when ever it appears moist The anhydrone in the Bubble Anhydrone tube should be replaced daily or whenever it appears moist The com bustion tube should be cleaned with a brush every 30 samples the tube should be inspected from time to time every 100 samples for severe pitting and slag build up If the tube is deteriorating it should be replaced 6 5 Thedust traponthe furnace should be cleaned and the glass wool repacked and conditioned every 20samples or whenever the Loop Pres sure reaches 6 psi It was found that an addi tional dust trap filled with Mg ClO was needed and the glass wool in this additional dust trap should be replaced at the same time The 10 micron mesh dust filter should be cleaned daily using an ultrasonic cleaner About ten minutes is required for this opera tion Glass Wool Conditioning The glass wool should be conditioned by heating a crucible with 0 3 g to 0 4 g of a sample containing more than 0 3 sulphur One scoop of iron chips and one tin pellet are also added to the crucible prior to heating This operation is only necessary when the glass wool is changed Carbon Sulphur Quality Control Quality control is carried out by analyzing one in house reference material every ten samples blanks are also run The optimum range for CO is 0 01 10 and 0 01 0 7 for S The instrumental detection limits of
232. e Protocol option otherwise the microprocessor locks up and the message waiting for RS232C appears on CRT 4 ENTER Sets the time of day Enter the appropriate two digit code when prompted 5 ENTER Sets the date Enter the appropriate two ditit code when prompted 6 ENTER Enter operator I D as a two digit code Key ENTER to cancel I D See Section 3 2 10 of the VIDEO 22E Spectrometer Operator s Manual for further explanation of the I O key AA Spectrometer Keyboard System Software A detailed description of the software menu for each key Mode Recall Store is provided in the VIDEO 22E Spectrometer Operator s Manual Default selec tions are indicated with an asterisk on the CRT Press ENTER to select the default condition To select any of the other options displayed on the CRT you must press the appropriate key then key ENTER Mode Menu The Mode menu is used to set the instrument parameters element optics background results statistics atomizer autosampler test and exit for in strument operation The following menu should appear on the CRT after the MODE key is pressed Mode 1 Element 2 Optics 3 Bkgnd 4 Results S E 01 0 5 Statistics 0 6 Atomizer CTF 7 Autosampler off 8 Test 9 Toexit 1 ENTER Select element or elements if dual channel is used Enter element number from the resulting table that appears and press ENTER 2 ENTER Select optics for each channel if AA D
233. e adhering silica 3 1 6 Finally wash the residue and filter paper 10 times with the hot 5 HCI solution Cover the funnel with ordinary filter paper and reserve Quantitatively transfer the contents of the beaker to the original casserole and evaporate the contents to dryness as before 3 2 Silica second filtration 3 2 1 Add 5 ml concentrated to the cool residue wetting all of the residue 3 2 2 Allow it to stand 1 2 minutes and then add approximately 50 ml distilled water Heat the casserole on the hot plate carefully until all soluble salts have dissolved 3 2 3 Filter without delay using a 12 5 cm Whatman No 40 filter paper in a 72 mm funnel as described previously catching the filtrate in a 400 ml beaker 3 2 4 Thoroughly police the inside of the casserole and the stirring rod and add all washings to the filter funnel Wipe the stirring rod and lip of the casserole with a piece of filter paper and add it to the funnel 3 2 6 Finally wash the paper and the residue 10 times with hot 5 solution paying par ticular attention to the upper edge of the paper Lift the paper to drain the stem of the funnel and rinse the tip of the funnel into the beaker 3 2 7 Cover the beaker and reserve the filtrate for other determinations NOTE A small amount of silica still escapes recovery and goes into the filtrate from the second evaporation and filtration This is recovered from the R O
234. e and sandstone contain rather less phosphorus than igneous rocks A few hundred parts per million being typical Deep sea sediments contain up to a few thousand parts per million P Os In this method the concentration of phosphorus is determined by measuring the absorbance of the yel low coloured molybdovanadophosphoric acid com plex produced by adding ammonium vanadate and ammonium molybdate to the sample The measure ment by a photometer is taken at wavelength 460 nm This method is used only where the sample matrix makes determination by XRF unsuitable e g when the sulphur content of the rock is too high to allow a fused bead to be prepared for XRF determination This method is also applied when the content is gt 1 0 and beyond the calibration range 0 1 0 of the current XRF method This method is used for accurate determinations such as where a standard reference material has to be analyzed for certification purposes A preliminary separation of phosphorus is sometimes made to eliminate the interference of elements such as copper nickel and chromium which form coloured solutions Presence of titantium phosphate can cause dissolution problems Safety advisory 1 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17 Method The method consists of the following techniques 1 Sample decompositio
235. e bibliog raphy Comments specific to As determination Magnesium oxide is used in the fusion of sample to capture any arsenic which may otherwise escape due to volatilization The fusion cake in the nickel crucible can be dissolved in distilled water more readily if it is warmed on a hot plate at low heat for half an hour Cu and Ni in concentrations of 20 and 10 ug ml interfere with the analysis Forsamples containing organic materials addition of approximately 1 ml or more of concentrated nitric acid during digestion is recommended Comments specific to Sb determination Avoid digesting the sample to dryness which will result in loss of Sb Potassium iodide is an essential component of the analysis system It quantitatively pre reduces Sb in the presence of HCl to Sb prior to the reaction with sodium borohydride and hence improves the sensitivity as well as the precision of the deter mination When the system is ready to run itis good practice to condition it first by repeatedly analyzing a stan dard solution until a constant signal is attained prior to the actual analysis Cu Ni and As in high concentrations interfere with Sb analysis The tolerance limits are 3000 1500 and 750 ppm in rock respectively For samples containing organic materials addition of approximately 1 ml of concentrated nitric acid during digestion is recommended Comments specific to Bi determination Avoid digesting the s
236. e both the JY48P system and the Data collection disks from the two drives Leave the doors open and the switches at ON posi tions 9 3 Press the button BREAK on the keyboard terminal Quality Control The overall quality of analytical data for the Trace 2 method is as quoted in Table OES1 This has been devised from the Laboratories blind duplicate program over a 5 year period Quality control for the techniques which comprise the method are described below Preparation of check solution After each batch of samples has been analysed the remaining T2 rock solutions are collected When a sufficient volume approximately 3 to 4 liters has been collected the solution is filtered and becomes a check solution for the instrument quality control The following is the list of the concentration means and the associated standard deviations of that present solu tion EA18 19 Traces ICP OES Concentration Mean ppm Standard Deviation Be 0 89 0 052 Co 36 0 51 Cu 99 1 33 Mo Ni 105 1 15 Sc 24 0 47 Sr 303 3 06 V 199 1 95 Y 22 0 34 Zn 102 1 64 The above results are calculated on 60 observations with the exception of Be which is based on 26 obser vations Aliquots of the check solution are analysed with each batch of samples using the routine run protocol and the results are compared against those in the above table The number of standard deviations of the check solu tion away from the mean is calculated us
237. e client information file If the client file exists the new information is appended If the client file is new then the file will be created using the name the user entered at the beginning of the program In the case of a new file the program will initialize the file records and print out a message to this effect There is programmed protection against overwriting an existing file but no protectionis fool proof so pay close attention to any messages that may be printed out at this point in the program The program will then prompt for the following information Client s name Address City province and postal code More information to be entered The maximum number of records in each client file is 100 The program will print out the starting record number before it prompts you for the new information so the user can act accordingly 1 if a client file is filled then a new file can be started When no further information is to be entered the data is written to the client file and an appropriate message is printed The total number of clients on file will be wrirten to the last record of the client file The user can now produce a hardcopy of part or all of the file Option 3 Option 3 allows the user to modify names addresses etc in a particular record The program prompts for the number of records to be altered or lt 100 and then prompts for the individual record numbers The information in these records is prin
238. e command is DIR SY Alternate directory instructions include DIR BAD DY1 DIR VOL DY1 DIR BRIEF The first searches out the bad blocks the second gives volume number owner as well as file information The DIR BRIEF command yields an abbreviated directory useful for disks containing many files Disk Management Copying Deleting and Viewing COPYING FILES Copying files from the disk at drive SY to the a new initialized disk situated in drive DY1 is carried out as indicated below 1 Search the directory of the disk at SY DIR SY EA18 4 2 Note files to be copied 3 Files may be copied one by one using the instruc tion COPY SY XXXXXX TYP DY1 where XXXXXX represents the 6 character al phanumeric name of the file and TYP represents its type i e RAW raw data DAT ASCII data TAB tables etc The operator must pay attention to the punctuation and spacing in the instruction e g the period between name and type or ex tension The system then types out the name of the file and copies it in the direction indicated in the instruc tion Reversing the SY and DY1 addresses will reverse the direction of the copy 4 In order to copy many files of the same but different type e g XXXXXX RAW and XXXXXX DAT a wild card instruction can be used An asterisk is used to represent the type or extension For example COPY SY XXXXXX DY1 Similarly to copy files of the sa
239. e concentration is outlined quite exten sively on pages EA19 5 to EA19 12 Traces ICP MS 3 Performing Calculations There are two calculation algorithms in use An inter nal standard technique has been developed for Y and the Rare Earth Elements REE Hf Ta Nb Rb Cs Sr and Zr All other analyses utilize external calibra tion with signal drift compensation linear interpola tion 3 1 Select option 2 from the Apple II main menu The CONCAL menu will be displayed Place the intensity data disk in the right hand drive 32 Select the appropriate calculation algorithm 3 3 Enter the slot number for the printer card 3 4 Enter the parameter set name for the set used to collect the data 3 5 After 30 seconds or so the program will dis play the identifiers of all the runs saved to disk and prompt for the run number to be processed Select the desired run number 3 6 The program will prompt for the filename to be used to store instrument and preparation of QC data Enter the appropriate filenames If this function is not being used enter to bypass these functions 3 7 The program will read the intensity data Wait until the program is finished doing this and has displayed the prompt requesting a Default Dilution Factor Enter the factor 3 8 The program will prompt for any factors that are different from the default Enter these factors The program will perform the inten sity to concentrati
240. e determination of cesium in rock samples Channel conditions stored in DB PB GEORHO are listed below ELEMENT FLT COL DET XTL ORD UPL LWL KV ANGLE OFFS OFFS Cs La NO F F 1 1 80 15 75 40 91 865 2 00 Measurement program and link program are stored under GEORHO as MP21 and LP21 with calibration coefficient information in CP21 Background correction is applied as indicated below NR BKGR CHLI L1 CHL2 L2 CHL3 L3 CHL4 L4 16 0 Cs 1 1165 0 0000 0 0000 0 0000 Calibration without MA correction results in a good fit with a wide range of standards CESIUM SRM Literature Observed ppm ppm VSN 900 900 Mica Fe 200 205 GA 6 6 Mica Mg 55 59 GXR 3 200 178 NBS1633A 11 14 Determination limit is estimated to be 3 ppm EA16 13 Traces XRF APPENDIX B MASS ABSORPTION CALCULATION PROGRAM FOR APPLE IIE 10 D CHRS 4 20 FF CHR 12 30 DIM A 100 M1 100 M2 100 M3 100 81 100 B2 100 100 NS NO 200 HOME 205 PRINT PRINT THIS PROGRAM CALCULATES MASS ABSORPTION 210 PRINT COEFFICIENTS USING PRINT BACKGROUND COUNTS PRINT COMPTON SCATTER COUNTS PRINT MAJOR ELEMENT COMPOSITION 215 PRINT PRINT PRINT DO YOU WANT TO USE BKG COUNTS Y N INPUT AS 220 PRINT PRINT DO YOU WANT TO USE COMPTON COUNTS Y N INPUT BS 230 PRINT PRINT DO YOU WANT TO USE MAJOR ELEMENTS Y N INPUT CS 240 HOME 250 IF AS Y THEN 259 255 GOTO 300 For calculation on background 259 HOME P
241. e g iron minerals with Cu radiation Special problems may occur with mineral solid solu tions where the mineral composition lies between two end members e g olivine where the composition may lie between Mg and Fe end members The diffraction lines will shift accordingly between the two extremes and allowances will have to be made forthis shift when the search is being conducted 3 Identification of metamict minerals Certain minerals which contain radioactive elements may not give a pattern or one that is impossible to match This is because the radioactive disintegrations have disrupted the crystal lattice forming what are termed metamict minerals In most cases the original pattern may be recovered simply by heating the sample at 1000 C for one hour and re running it One possible complication is minerals that oxidize e g UO to U3O uality Control The above technique is a qualitative means of iden tification although abundances can be estimated using the relative intensities of each phase present The absorption effect is variable for each mineral present so these relative intensities can be misleading par ticularily if iron minerals are present A quartz sample should be run regularly to check that the pattern obtained is the same as the standard JCPDS one If not there may be an alignment problem The detection limits of minor phases depends entirely on their chemistry and on whether the mineral is likely to have a
242. e of 6 ml per minute if a variable rate nebulizer is used 2 5 2 Check for blockage in the nebulizer or solu tion deliver tube 2 5 3 Check spoiler bead position in bung 3 Sensitivity Check The absorbance of a check standard is analyzed and compared with previous data If the value is within 10 of the mean of previously amassed data the operator can proceed If not then optimization proce dures should be repeated oruntil the problem is found 4 CalibrateInstrument Use appropriate standards which encompass the nor mal range of samples or use the technique of bracket ing the sample with high and low standards 5 Analyze Samples Reagent blanks control standards and samples are analyzed Calibration is checked at intervals Use a distilled water rinse between samples and standards Samples with concentrations outside of the calibration Varian AA775 limit are diluted to fall within the working range and reanalyzed The analytical values are transcribed manually or cap tured by the instrument microcomputer LIQUID HANDLING SYSTEM A liquid handling system to complement the robotic system used for the decomposition of samples is avail able for certain applications The instrument is a Gil son Model 222 401 and is programmable to perform dilutions pipetting dispensing and partitions or any combination of these Programs are installed for 1 2 1 5 and 1 10 dilutions for up to 44 samples using the standard cultur
243. e to boot the system from the video terminal although once activated control can be passed to this terminal by typing R CHTERM R This instruction can be used to transfer control back and forth between terminals as long as the computer is in the RT 11 operating system Traces ICP OES NOTE In the following pages all instructions to the computer are underlined Itis assumed that all commands are followed by a carriage retum Once the computer has been booted the system re quests the operator to input the date Enter XX MON YY where XX day MON three letter abbreviation of the month and YY last two digits of the current year e g 17 AUG 87 The time can also be entered in the format HR MN SC where HR hour MN minutes and SC seconds e g 14 30 20 Formatting and Initializing a New Disk Any new floppy disk to be used in the system must be formatted and initialized To do this the new disk is placed in the RHD and the system instructed R FORMAT The system responds with a request for the location of the disk to be formatted by an asterick cursor and operator answers DY1 Since the operator may wish to re format a disk which had been used previously the computer asks for as surance that formatting is desired i e ARE YOU SURE If sure the answer Y is typed if not sure N or Ctrl C press the control Ctrl key and depress the C To double check that an old disk has no
244. e tubes A maximum of 110 samples can be diluted using culture tubes when five racks of test tubes are available The procedures are performed automatically and unattended and are initiated through a keypad although the system may be subjugated to a host computer via an optional interface Programs can be written according to your needs or existing programs modified A variety of test tube racks is available to use with the system The racks are individually coded so that the probe will find test tube positions To use a rack of your choice will require extensive initialization for each test tube position Four glass syringes 0 5 1 5 and 10 ml covering a range of 2 to 11000 microliters are available There is a 5 ml and a 10 ml syringe using a piston with a PTFE ekonel seal for use with acids The following table shows the performance expected for 5 ml and 10 ml syringes respectively Set Volumes Accuracy Precision microliters 30 aliquots 5000 0 5 0 05 2000 0 5 0 05 1000 0 5 0 08 500 0 5 0 1 200 1 0 0 2 100 2 0 0 3 50 3 0 0 5 20 5 0 1 0 10000 0 5 0 05 5000 0 5 0 05 500 1 0 0 2 200 2 0 0 3 100 3 0 0 5 With the 5 ml syringe the maximum volume of sample that can be dispensed is 5 ml sample diluent This means that 1 2 dilutions will yield a maximum of 5 ml Liquid Handling System of diluted solution 2 5 ml of sample and 2 5 mi of diluent PROGRAM FOR 1 1 DILUTIONS Stored Under File Number 22 RACK CODE 2
245. e until the decanted water is clear The final rinse should be with acetone or alcohol to speed drying Dry the sample under a heat lamp or in a warm oven ovemight When dry sieve the sample using clean nylon cloth sieves The usual size is 100 140 mesh but the grain size of the rock will be the major factor in deciding what size should be used The sieve clothes can be placed over the mouth of a 500 ml jar attached with rubber bands containing approx 100 ml sample Shake the jar until no more grains pass through When about 50 ml of the desired size range is available start the magnetic separation and complete the sieving of the rest of the sample later Before putting the sample in the feed hopper pass the hand magnet over it once more to remove any leftover magnetic grains The magnetic separator should be thoroughly cleaned prior to starting the separation Brush the pole pieces carefully as well as the trough behind them which often contains minerals from the previous separation Stand the pole pieces vertically and brush them out Sample cups the feed hopper and other surfaces in contact with the sample should be wiped with tissue paper soaked in alcohol The chute must not be wiped or touched with the fingers if it is greasy wash it in detergent and hot water and let it dry Otherwise blow it clean and reassemble the pieces The initial settings are 10 side slope 20 forward inclination The feed is into the inner chan
246. ead 9 713 0 060 9 653 g SiO in bead 1 440 9 653 14 92 Result expected from XRF analysis 14 92 15 44 x 100 96 61 EA6 14 Majors XRF Flux correction Wt Si in 1 500 g sample 0 96 x 1 500 1 440 g Additional wt flux used 0 06 g Wt finished bead 9 713 g 9510 in finished bead 14 83 Result expected from XRF analysis 14 83 15 44 x 100 96 02 Example 3 Sample 85 SiO LOI 15 No correction Wt Si in 1 500 g sample 0 85 x 1 500 1 275 g WL finished bead 9 488 g TSiO in finished bead 13 44 Result expected from XRF analysis 13 44 15 44 x 100 87 03 Sample weight correction Wt sample used 100 85 x 1 500 1 765 g WL Siin 1 765 g sample 1 500 g Wt of finished bead 9 713 g 96SiO in finished bead 15 44 Result expected from XRF analysis 100 before correction factor After application of factor 85 100 result 85 EA6 15 Majors XRF APPENDIX B METHOD DEVELOPMENT Setting Up a Routine Analysis Program Majors This section is included to illustrate some of the methodology that has been used to develop the routine methods A knowledge of these procedures will enhance the operator s ability to perform accurate routine analysis Establishing the Parameters Creation of the various banks and indication of how to use instructions is illustrated through the example of setting up a routine analysis program The example shows the process
247. eagent preparation 1 1 1 Sterox SE non ionic wetting solution Add 10 ml of Sterox SE solution to a 1 liter flask and make to volume with distilled water 1 2 Li Stock Solution 1500 Weigh ac curately 55 4175 g of Li CO and transfer to a clean 1 liter glass beaker There is no need to dry Li CO since the standards and blanks are prepared in the same fashion 1 2 1 Cover with a clean watch glass and add about 100 ml of distilled water 1 2 2 Add caustiously small portions of 200 ml conc 1 2 3 Once the effervescence has stopped and dis solution is complete cool and transfer quan titatively to a 1 liter volumetric flask by washing the beaker with several small por tions of distilled water 1 2 4 Add 10 ml of 1 Sterox SE solution mix and make to volume 1 liter with distilled water Store in a polyethylene bottle 1 3 1 Preparation of 1 1 HSO solution Add very carefully 100 ml of conc H SO using a graduated cylinder to a 200 ml volumetric flask already having approximately 75 ml of distilled water and mix 1 3 3 Immediately immerse the flask in a 600 ml glass beaker or tray containing cold tap water as the solution will be very hot due to the reaction 1 3 3 When cool make to volume with distilled water and store in a glass bottle 2 Standard Na and K solution preparation 1000 ppm Na and K 2 1 Weigh exactly 2 5423 g of NaCl dried at 105 C and transfer quantitat
248. ecision at the 95 confidence limit 26 at a mid range value of 0 456 absolute Table 1 20 and K20 Values for SRMs Obtained By Using Li as an Internal Standard SRM Na20 K20 GLOGS Lit GLOGS Lit SY 2 4 34 431 464 445 SY 3 4 20 4 14 4 204 420 MRG 1 0 77 0 73 0 17 0 18 AN G 1 73 1 63 0 19 0 13 BEN 3 36 3 18 144 1 39 AL 1 10 66 10 59 0 14 0 14 NBS 91 8 47 8 48 3 28 3 25 NBS 70A 2 48 2 55 11 7 11 8 Sodium Potassium Productivity A technician should be able to complete 10 samples per day Additional Notes 1 Samples high in sulphur should be roasted first in Vycor brand glass crucibles 30 ml in a furnace at 650 C for 3 hours or preferably overnight Then transfer the powder quantitatively from the crucible to the platinum dish Rinse crucible with several portions of distilled water and finally with HCl into the dish 2 This method is applicable to most of the rock samples where Li is present in trace amounts 0 100 ppm Rocks containing large amounts of Li are rare Bibliography Jeffery P G Chemical Methods of Rock Analysis First Edition 1970 Maxwell J A Rock and Mineral Analysis Wiley Interscience Publishers 1968 pp 405 Instruction Manual for the Flame Photometer Model FLM2 December 1970 Bach Simpson Ltd 1255 Brydges St London Ontario EA11 5 DETERMINATION OF WATER Water COMBUSTION INFRARED ABSORPTION METHOD Introduction Waterexists in two main form
249. ecreases then the slow direction of the plate is parallel to the fast direction of the mineral The fast and slow directions are partially diagnostic in the identification of mineral phases 3 2 Interference figures determination of optic sign and measurement of 2V Interference figures are obtained as follows focus on a grain with a high power objective and center the grain in the field of view center the microscope and raise the sub stage condenser opening the sub stage diaphragm Using cross polarised light insert the Bertrand lens The stage should be rotated when ob serving interference figures so that the pattern of the isogyres can be noted Interference figures indicate whether the the mineral is uniaxial or biaxial and with the aid of the sensitive tint plate the optic sign can be determined 2V can be obtained on biaxial minerals These properties can all be determined from grains cut parallel to circular sections of the uniaxial or biaxial indicatrix Therefore the best grains are those with the lowest interference colours black or grey Such grains give a uniaxial cross or a biaxial optic axis figure Isotropic minerals will not produce an interference figure 3 3 Use of accessory plates to determine optic sign To determine the optic sign interference figures and sensitive tint plate are used together In uniaxial figures the vibration directions are radial to the direction Insertion of the pla
250. ectronic Balance Cylinder of nitrogen with regulator capable of accurately delivering N at pressures of 30 to 50 psi Nickel boats Tongs Push rod Glass wool Hi vacuum grease Brush Spatula Reagents Anhydrone magnesium perchlorate Procedures 1 Instrumental Analysis 1 1 gas on switch to off 1 2 Tum on nitrogen supply and set regulator to 40 psi 1 3 Switch power to on The message centre will display POWERUP DIAGNOSTIC while the instrument performs a diagnostic test 1 4 After completing the test the message centre wil display ENTER TIME AND DATE Hr Min Mo Dy Yr Using 24 hour time enter the correct time and date Use the num berkeys onthe instrument and push ENTER after the information has been keyed in 1 5 Switch on front panel gas and adjust the Purge flowmeter to 3 litres per minute 1 6 Switch the Pump on and ensure that the Analysis rotameter is set to 1 litre per minute 1 7 Press System Update key then press the YES key 1 8 Allow 1 2 hour for warm up 1 9 Run 2 reference samples Typical reference materials are MRB 7 and MRB 10 which con tain 2 31 and 11 7 respectively H5O If the results from these analyses are not within 5 ie 2 20 2 43 of the expected values re standardize the instrument and rerun the reference materials EA12 1 Water 1 10 Runablank Run the samples The run should consist of Blank Refe
251. ed and becomes almost insoluble in dilute NOTE Thermofab cloth on the hot plate and moderate temperature prevents splattering of the residue of silicic acid and other salts at the final stage of drying 3 Determination of SiO 3 1 Silica first filtration 3 1 1 To the cool residue add 5 ml of concentrated HCl wetting all of the residue and particularly the ring marking the original level of the liquid in the casserole from which it is difficult to remove particles of silica NOTE If distilled water is added first insoluble basic salts of iron are apt to form especially if the residue is warm NOTE The first filtrate from the silica still contains a small amount of silicic acid which requires a second evaporation for recovery This usually amounts to 10 mg SiO 3 1 2 Allow to stand 1 2 minutes and then add ap proximately 50 ml of distilled water washing down the sides of the casserole and the stirring rod Cover and carefully heat the casserole on the hot plate until all soluble salts have dissolved as indicated by an absence of gritty particles This heating should not be prolonged in order that as little as possible of the silica will be Majors Classical dissolved and more water may be added if necessary in order to make fast dissolution of the salts 3 1 4 Remove from the hot plate and filter into a 250 ml beaker using a 12 5 cm Whatman No 41 filter paper 3 1 5 Use a policeman to remov
252. ed at a photo sensitive detector such as a photomultiplier tube or diode array The number of emission lines can be very large especially for ele ments with relatively high atomic number as there is generally a large number of accessible upper energy states available for the excitation The wavelength of the emitted light is related to the energy difference between states The relative inten sities of the emitted lines fora given constant analyte concentration is related to the energy state populations and transition probabilities In the absence of spectral or non spectral matrix effects the intensity I of the emitted light for a defined analyte at a given wavelength will be directly proportional to the con centration of the analyte C in the sample Izk C Furthermore in a system containing pure analyte the signal S obtained from the detector will be linearly dependent on the intensity of the emitted light S k D B where background contribution from sample matrix e g solvent and from the instrument stray light electrical noise etc Since we use calibration curves to convert analytical signals to concentration it is more convenient to rep resent C as a function of S thus EA18 7 Traces ICP OES C A1 where A1 and AO are the appropriate slope and inter cept calibration coefficients respectively At high analyte concentrations deviations from linearity
253. ed value when considered as members of the population of contributed data Productivity A technician should be able to complete 4 samples per week Additional Notes 1 Beakers funnels flasks and other glassware should be cleaned well before use If greasy a rinse with chromic acid cleaning solution is desirable Rinse vessels thoroughly with tap water and follow with distilled water 2 Wash solutions of various kinds are called for in the course of the analysis To save time special wash bottles containing 2 ammonium nitrate 5 HCl 5 ammonia and 0 1 ammonium oxa late solution are kept on hand EA8 10 3 All beakers casseroles flasks etc containing solutions being analyzed must be labelled to prevent confusion and mixing of samples 4 Two points on washing precipitates 1 There is a danger of losing some of the precipitate if too vigorous a jet from the wash bottle is used 2 In washing use small quantities of wash liquid and let each portion drain through before adding the next 5 Preliminary heating of a crucible containing a wet paper and precipitate should be very slow until the water is removed a very gradual increase of temperature follows until the volatile matter from the paper has been smoked off During this stage do not allow the gases from the paper to burn with a flame since this may result in drafts and loss of precipitate Then increase the temperature to a dull red heat until all ca
254. electrodes noting polarity cathode black anode red 1 2 Carbonate carbon apparatus set up Figure CC1 shows the assembled CO apparatus For tubing connections follow the procedure shown in the manufacturer s instruction manual 1 2 1 Fill air scrubber with approximately 12 ml of 45 KOH solution 1 2 2 Fill sample scrubber tube with 50 KI solu tion 1 3 Operation 1 3 1 Weigh and transfer sample 0 05 g to 0 50 g depending on the carbonate content into a sample tube Moisten the sample with approximately 0 5 ml of distilled water Place the sample tube on the heater of the CO apparatus Place the condenser on top of the sample tube Besure system is leak free Switch on the air pump and purge the system Connect the scrubber outlet of the CO ap paratus to the gas inlet of the coulometer cell Press the reset button on the coulometer to zero carbon reading Press the plunger on the acid dispenser to dis pense about 2 ml of acid EA28 2 1 3 10 Turn on the heater and adjust heating as desired 1 3 11 Allow sufficient time 10 30 minutes for com plete reaction and record carbon reading when coulometer gives a steady maximum reading 1 3 12 Run a blank by heating 2 ml of 2N similarly but omitting the sample 2 Calculation of the results The CO content of the sample is calculated according to the following formula Micrograms C bla
255. en using racks coded 22 with the 123mm arm In the example program above the true height of the probe from the bottom of the test tube is the value given minus 60 mm PROCEDURE FOR PERFORMING DILU TIONS The following dilution programs have been installed for use with a 10 ml syringe 1 dilutions File Number 22 1 5 dilutions File Number 15 1 10 dilutions File Number 110 Instructions 1 Make sure all tubing keypad probe and syringe are installed correctly see manual Place samples into test tube racks such that the y axis B in program maximum 11 is loaded first Make sure sufficient sample and diluent is available for the complete run Plug in dilutor and sample changer Switch on dilutor Model 401 then sampler Model 222 in this order otherwise a message DILUTOR ABSENT may appear Messages MODEL TEST and MODEL 222 V3 O will appear Prime the system by pushing PRIME on keypad To stop prime push PRIME again Press EDIT SAVE FILE key to search for the required file Press ENTER when the required file is found and continue to press ENTER until FILE STORED appears on display Press START to initiate program A message will appear on display requesting input of number of samples to be run Note Above program is currently set for a minimum of 1 and a maximum of 44 Program will now complete dilutions and retum probe to HOME position When finished wash system out with distilled water by
256. ences through the use of background correction and interference correction coefficients The magnitude of the transduced photomultipler signal is controlled by the sensitivity of the detec tor The JY48P permits separate control of the sensitivities for all channels by adjustment of switches on voltage control cards Channel response is set in accordance with the expected abundance of the analyte in normal geological samples The general operation of the system for the analysis of samples is described by the schematic diagram shown below Features include source and sample delivery under manual con trol spectrometer under partial computer control i e entrance slit position profile scanning channel profile selection for external scanning polychromator data acquisition at all channels manual control of detector sensitivities detection under computer control i e replicates integration time flush and delay times etc machine language raw data files RAW for all channels and at all slit positions for background correction stored automatically in polychromator data acquisition routines ASCII analytical data files DAT are program controlled translations of the raw data files The DAT files obtained by processing the raw intensities through software TABLE files contain information as intensities counts or concentrations for selected elements These data can also be corrected for backgr
257. end 37 mm past the tip of the aerosol injector 1 long torch Thetorch should be positioned in the work coil so that the distance between the aerosol injec tor and the bottom tum of the load coil is 2mm The torch stand should be positioned so that when it is at the extreme end of its travel towards the torch the injector tube is 43 mm away from the sampling orifice and the top turn of the load coil is 23 mm from the sam pling orifice After this distance has been checked by eye move the box away from the sampling orifice until it rests against the back stop The box will be returned to the stop position after the plasma is ignited Traces ICP MS 1 1 4 Visually ensure that the load coil centre tap solder join is intact and the interface torch cooling water is on 1 2 Starting The Computer 1 2 1 Activate the printer using the toggle switch at the back left hand comer 1 2 2 Activate the Envision monitor terminal using the switch at the back left hand corner 1 2 3 Wait 10 15 seconds 1 2 4 Activate the Elan computer using the switch labelled POWER on the face of the com puter 1 2 5 Wait 30 seconds 1 2 6 Press the switch labelled RESET on the Elan computer panel 1 2 7 Wait 3 4 minutes until the following mes sage appears at the top of the monitor XXXX Files XXXXX Blocks XXXX Free If there are more than 3000 files or less than 700 free DO NOT PROCEED Contact the person r
258. ent QC The program will then ask whether the con centration data is to be stored Respond ap propriately If the data is not to be stored the program will retum to the CONCAL main menu If the data is to be stored three options will be presented 1 Routine Sample Data Storage 2 International Reference Material 3 In house Reference Material Some or all of these op tions may be used for one set of data The program will display each sample iden tifier and prompt for the proper run identifier Routine sample data should be stored using the four digit run number assigned by the lab i e job number The program will prompt the operator to place the appropriate data disk in the right hand drive Place the disk in the correct drive When all data has been stored the program returns to the main CONCAL menu 8 Instrument Shut Down Normal Operation 8 1 1 8 1 2 8 1 3 Tum off the detector Unlock the torch stand Depress the Operation button OFF and as the gate begins to rise steadily move the torch stand away from the interface plate Slowly but steadily decrease the forward power until the plasma extinguishes and then depress the RF OFF button EA19 11 Traces ICP MS 8 1 5 Tum off the water to the interface and the load coil 8 1 6 Allow the RF generator to cool for 10 minutes before shutting it off 8 1 7 Exit the ELAN control programs software shutdown 8 1 8 Turn
259. ent information file and element identifier file are present 4 Enter R INFORM For details see INFORM 5 Enter R ELEFIL For details see ELEFIL 6 Enter R WORCER For details see WORCER INFORM The INFORM program allows a user to enter delete verify or save client information names addresses etc into a DAT file on the system disk The program will first prompt for the client information file name The first time this program is run the file will be created on the system disk The program will then present the following options 1 Verify the client information on file EA18 26 Traces ICP OES 2 Enternew information 3 Change information in a record Option 1 Under option 1 the user can obtain a hardcopy of part or all of the client information on file The program will tell the user how many clients i e the total number of records are on file and then prompt for the number of records to be printed If the whole file is to be displayed then enter the total number of records on the file If only part of the file is going to be displayed the user will then enter in the particular record numbers of interest The client information will be printed out and the program will terminate execution This option should be used whenever new information has been entered since an updated hardcopy of this file is required when the WORCER program is used Option 2 Option 2 is run when new information is to be saved into th
260. enter the ACD routine at any SRM e g ACD 4 enters the routine at the fourth SRM To view the total concentration file the operator types EA6 26 Majors XRF PCD Print concentration data when finished the file is closed CLF Close file Regression After all intensities and concentrations are entered into the MAJORS RO file the regression is performed To do this the operator leaves the X14 software by typing END and enters the regression software MCR REG The system requests the regression filename The response is the data filename MAJORS ROI or file required For theories on the interpretation of XRF data the reader is referred to R H Jenkins and B DeVries Worked Examples in X ray Spectrometry Springer Verlag New York 1970 The default calibration procedure is the De Jongh model DJ which is a concentration based correction model The general formula is where C concentration of analyte R intensity of analyte E slope of calibration curve D intercept of curve aj alpha coefficient for interferent j Cj concentration of interferent j This formula is similar to the Lachance Trail model but corrects for self absorption It is used extensively and has proved successful for most applications Constants D and E are instrument dependent alpha coefficients are fixed and known for any sample spectrometer combination and can be input from tables or calculated during the regressio
261. ents Hydrochloric acid HCl 38 Borohydride solution Argon gas Sodium hydroxide pellets NaOH Magnesium oxide Hydrofluoric acid HF 49 3 Sulphuric acid H SO 96 Potassium iodide solution Perchloric acid HCIO 60 Digestion mixture Masking agent Stock arsenic standard solution 1000 g ml Working arsenic standard solutions Stock antimony standard solution 1000 ug ml Working antimony standard solutions Stock Bismuth standard solution 1000 g ml Working bismuth standard solutions Procedures 1 Reagent preparation 1 1 1 1 1 2 1 2 1 3 2 1 4 Borohydride solution Dissolve 3 g of sodium borohydride in 300 ml of distilled water Add 3 pellets of sodium hydroxide Store in a refrigerator when not in use Digestion mixture 1 Mix equal volumes of hydrofluoric acid sulphuric acid and distilled water Store in a polyethylene bottle Potassium iodide solution Dissolve 10 g of potassium iodide in 100 ml of distilled water Add 2 pellets of sodium hydroxide Digestion mixture 2 Mix hydrofluoric acid perchloric acid and distilled water in the ratio of 2 2 1 Store in a polyethylene bottle Masking reagent Dissolve 0 5 g each of thiosemicarbazide and 1 10 phenanthroline in 100 ml of 0 1M HC solution 2 Standard As Sb and Bi solution preparation 2 1 1 Stock arsenic standard solution 1000 ug ml Dissolve 0 132 g of arsenic oxide As Q3 in 2 ml of 1M NaOH acidify
262. eparation of Pressed Powder Pellets for XRF Determination of Trace Elements in Rock Pow der 1 1 1 Wearing gloves weigh 5 0 g 0 1 g of 200 mesh rock pulp into a 7 dram snap cap plastic vial 1 1 2 Add three drops of polyvinyl alcohol solution to serve as a binder and biend into the pow der by stirring with a nickel spatula EA16 1 LACES 1 1 3 Transfer the sample to the 40 mm die to which an aluminum former sleeve has been added 1 1 4 Pack the contents with a plexiglass plunger to form a compact puck 1 1 5 Remove the sleeve and plunger and add the boric acid powder placing it on top of the sample A measuring vial in the boric acid container indicates the amount to be added Complete the assembly of the die and form the pellet by application of 15 tons pressure for 15 seconds using the pellet press Removed the pellet from the die and label it with a felt tipped marker on the boric acid side 1 1 8 Leave the pellet face downona cellulose wipe for 24 hours to allow the binder to dry A well made pellet should have no cracks an even surface and the rock powder should be centered within the outer ring of boric acid If a pellet is considered unsuitable a new one is made from a fresh subsample of rock pulp It is important to keep the dies clean Boric acid and rock powder can build up on the surfaces and con taminate subsequent samples A thorough cleaning with a cellulose wipe after each
263. er and the stirring rod with a small piece of filter paper and add this to the funnel NOTE It is difficult to wash this precipitate thorough ly due to its gelatinous nature By re dissolv ing in acid and re precipitating a much better separation is effected 42 re precipitation 4 2 1 With the aid of platinum tipped forceps remove the paper from the funnel and carefully spread it out on the inside wall of the original beaker 4 2 2 Wash the precipitate from the paper with a jet of hot 5 and rinse the walls of the beaker and stirring rod also 4 2 3 Place the beaker under the funnel and rinse the funnel with 5 then with distilled water 4 2 4 Finally wash the paper once or twice with distilled water fold the paper into a triangle with forceps and drape it over the rim of the beaker 4 2 5 Heat the contents of the beaker until the precipitate has dissolved add more 12M HCI if required 4 2 6 Dilute to about 150 ml and heat to boiling 4 2 7 Repeat the precipitation as previously described but when the end point has been reached add 2 to 3 drops ammonia in excess and add the filter paper to the solution shred ding it with the stirring rod and forceps and stirring vigorously to macerate it thoroughly NOTE The added pulp from the macerated paper aids in the filtration to follow Furthermore when the hydroxide precipitate is ignited the presence of the paper gives the ig
264. er close the shutter and change the sample The next scan can be started as above Peaks on the previous chart can now be iden tified and their 20 angle marked A rule of thumb for distinguishing peaks is that they be at least two times background The d spacing can then be read of a chart which gives the d spacing for a given 20 angle for Cu radia tion The peaks are then ordered in terms of intensity for most purposes only the three or four most intense peaks need be ordered but the process for mixtures is more complicated The indexing of the pattern can now take place 2 Indexing The Hanawalt system is used for the indexing of pat tems This system takes the three strongest intensities on the pattern and uses the JCPDS search manual which lists the intensities for almost 48 000 pattems This is a huge volume of information which would make searches long and difficult as well as giving many different possibilities for each pattern For tunately there are a number of ways of dealing with this information overload As this laboratory deals almost exclusively with minerals we need only to use the JCPDS Mineral sub file which lists every known naturally occurring substance some 3 500 in all Secondly some preliminary information about the un known mineral is usually available this would include knowledge of the mineral properties colour hardness etc crystallography and mineral association All of this information is help
265. er is indicated on the forward power meter Maintain contact with the power dial it may be necessary to adjust it for more or less power during the ensuing operations Activate the tesla coil by depressing the white ICP IGNITE button located on the torch stand control panel It may be necessary to adjust the forward power up to initiate the plasma or down to stop arcing NOTE Arcing from the coil to the torch accom 1 3 15 1 3 16 1 3 17 1 3 18 panied by the green Cu emission sparks and the sound of RF arcing occurs occasionally particularly when 1 4 kW power are used instead of 0 5 kW If this happens QUICK LY rotate the power knob COUNTER CLOCKWISE i e to OFF Push the RF POWER OFF button A check should then be made to ensure the load coil centre tap solder join is intact and the interface torch cooling water is on Atthis point the plasma should light If it does not ignite after a few seconds press the RF POWER OFF button and consult the senior technician or Supervisor Rotate the power pot to select a forward power setting of 1 5 kW as indicated on the Forward Power Meter The following operations should be per formed quickly depress the Operation button ON switch the RF Reflected toggle switch ON the power knob to MAX fully clockwise open the nebulizer gas line via the needle value to 1 0 l min Wait for the interface gate to begin dropping then
266. esponsible for the ELAN NOTE The Elan software relies on the use of a color coded numeric keyboard In the procedures described here the following short forms for references to operator responses using this keypad the keys are numbered left to right 1 2 and 3 G Grey R Red Y Yellow B Blue and Gn Green 1 2 8 At the Login prompt type Elan Then type in Y R to the prompt Does the printer need initialization 1 2 9 Press B3 The screen should now display text titled ECL Commands Make sure caps lock is off The computer is now operational 1 3 Starting the Plasma Source 1 3 1 Tum on the RF Generator by depressing the CKTS push button EA19 5 Traces 1 3 2 1 3 3 1 3 4 NOTE 1 3 5 NOTE 1 3 6 1 3 7 1 3 8 1 3 9 1 3 10 1 3 11 19 6 ICP MS Tum the reflected power switch on the APCS 3 panel to OFF Tum the power pot on the R F generator to a setting of about 8 2 Check that the voltage to the channel electron multiplier CEM detector is switched off by checking that the left hand toggle switch on the fourth board from the top in the signal and ion lens electronics rack is set to the left One lead of the R10 resistor on the CEM board has been disconnected This is to ensure that the CEM on off toggle switch will always tum off volts to the detector independent of the computer status If the lens quadrupole power supplie
267. ethod An estimate of precision at 95 confidence limit 26 for a mid range value is 0 1 absolute with a mid range value of 0 5 The accuracy would be similar to this value for SRMs Productivity A technician should be able to complete 15 determina tions per day Additional Notes 1 Samples high in sulphur should be roasted first in a Vycor brand glass crucible 30 ml in a fumace at 650 C for 3 hours or preferably overnight then transfer the powder from the crucible to a platinum dish Rinse the crucible with several portions of distilled water and finally with concentrated into the dish Titanium 2 Titanium minerals are considerably more resistant to decomposition than the silicate matrix in which they occur Care must be taken to ensure that the mineral grains are completely attacked 3 Any residue which could contain such minerals as rutile and ilmenite should be fused with small amount of potassium pyrosulphate K S 0 in Vycor brand glass crucible 30 ml 4 The residue and the filter paper from filtration of the digested sample solution should be ignited in a Vycor brand glass crucible using a muffle fur nace Start with a cold furnace and burn off the paper allowing the temperature to rise slowly Ignite the residue for about 5 minutes at 600 C Then fuse with potassium pyrosulphate 100 to 300 mg depending upon the amount of residue present After leaching the fused matter in 596 H SO
268. experienced the same inadequacies for strongly alkaline undersaturated plutonic rocks As a result a calculation similar to that for the standard CIPW norm Washington 1917 modified by Barth 1931 has been devised for these rarer igneous rocks The new calculations have been specifically created for ijolitic nephelinitic and melilite bearing suites of igneous rocks but is also applicable to other under saturated and strongly alkaline rocks which lack Ca plagioclase This would include the peralkaline syenites alkali pyroxenites peridotites and nepheline syenites ultra alkaline rocks and volcanic equivalents of the classificatory system described by Nockolds 1954 and many ofthe feldspathoidal peralkaline and metaluminous rock types defined by Shand 1949 The criterion governing the use of this norm is that it is appropriate for undersaturated rocks when either or both acmite or calcium ortho silicate CS appear in the CIPW norm The main features of this norm are 1 It allows the calculation of nepheline as Na3KALSi4O the formula preferred by Hamil ton and Mackenzie 1960 and Barth 1963 In the CIPW norm nepheline is calculated free of the kalsilite molecule KAISiO which frequently gives rise to leucite in the norm and unnecessary silica deficiency elsewhere 2 Itfavors the formation of the minerals pervoskite sphene andradite kalsilite and melilite both aker manite and gehlenite end members A more ac
269. extin guished The general procedures to follow with any atomic absorption unit set up are 1 Preliminary Safety Check 1 1 Compressed gas cylinders securely fastened 1 2 Exhaust ventilation fan on and operating 1 3 Burner head clean and corrected installed 1 4 Water trap or loop properly filled 1 5 Adequate supply of compressed gases to com plete the task 2 Parameters to be Set Parameters are set according to the information recom mended by the manufacturer or contained in the infor mation sheets for each element These are found at the end of each section of this manual relating to deter mination by atomic absorption In addition the follow ing optimization procedures should be performed 2 1 Lamp alignment 2 2 Instrument gain 2 3 Burner alignment 24 Flame stoichiometry Flames have different temperatures and analytical characteristics not only because of the gases used but also because of their ratio The following guide is used to describe the flame Coolest reducing Fuel rich luminous air acetylene glows bright yellow nitrous oxide acetylene a blinding pink white Medium stoichiometric Balanced fuel and oxidant air acetylene has a slight yellow tinge nitrous oxide acetylene has about 15 to 20 mm high red feather Hotest oxidizing Fuel lean air acetylene is blue nitrous oxide acetylene has about 5 to 10 mm high red feather 2 5 Solution uptake rate 2 5 1 Adjustto rat
270. f STD C to provide three significant figures Because the PS 75 prepares standards from the same mixed stock solution entry of the first standard in channel B establishes the other standard values The CTR displays a diagram of the sample changer to aid in setup for example STK CONC A B AUTO CAL A 0 100 0 100 X SAMPLE STD 0 EMPTY TUBE RNS STK A Z A C row lt 2 000s Qmd uti 3 A meeee Seo wee 5 LOAD RACK AT THIS TIME l Prepare 2 PrepareandRun 9 Toexit k STK CONC s are the concentration of A and B ele ments in the stock analyte solution to be prepared and placed in the second large vessel from the left Provide sufficient empty test tube this example has 3 for standard preparation If 1 Prepare is selected the Prep Station will only prepare the standards EA3 4 If 2 Prepare and Run is selected both preparation and analysis will proceed automatically When using the Sample Changer with the CTF 188 do NOT press the escape ESC key on the 188 unless an emergency situation requires immediate cooldown of the furnace If the AA microprocessor locks up restart the system by turning off the Sample Changer power go to RESTART STDBY on the AA back to OPERATE and re initiate power to the Sample Changer NOTE In the furnace mode the Sample changer auto matically pauses in the sipper up position between each sample while nebu
271. f answer is no then Do analysis using a different para meter set If answer is still no the program returns to the main menu If answer is yes the program will proceed and will ask for parameter set name etc as before Be certain to place appropriate data disk for new parameter set in the right hand drive BEFORE ENTERING THE NEW PARAMETER SET NAME 7 Performing Calculations There are two calculation algorithms in use An inter nal standard technique has been developed for Y and the Rare Earth Elements REE Hf Ta Nb Rb Cs Sr and Zr All other analyses utilize external calibra tion with signal drift compensation linear interpola tion 7 1 1 Select option 2 from the Apple main menu The CONCAL menu will be displayed Place the intensity data disk in the right hand drive 7 1 2 Select the appropriate calculation algorithm 7 1 3 Enter the slot number for the printer card 7 1 4 Enter the parameter set name for the set used to collect the data 7 1 5 After 30 seconds the program will display the identifiers of unprocessed runs and prompt for the run number to be processed Select the desired run number 7 1 6 The program will prompt for the filename to be used to store instrument and preparation QC data Enter the appropriate filenames If this function is not being used enter to bypass these functions 7 1 7 Theprogram will read the intensity data Wait until the program is fini
272. f data files with com mon alphanumerics e g ABOOOI DAT AB0002 DAT AB0003 DAT etc the typed instruc tion would be TYPE AB DAT If there is a series of files ABOOOI DAT to ABO800 DAT and one wished to print out only from 500 0599 the instruction would read TYPE AB 5 DAT In some cases a code letter can be incorporated into a file name for convenience i e B for blank Q for quality control or S for standard If all files of a specific code type are required then the instruction would read TYPE S DAT and all DAT files containing an S in the name will be typed EA18 6 CONTROL COMMANDS In addition to the Ctrl C command which can be used to exit from any program and to return to the RT 11 monitor there are a number of other Ctrl commands which are useful Cul O stops generation of output and retums system to monitor or program initialization Ctrl U deletes a line of typing Ctrl S 0 Ctrl A temporary halt to output awaits restart Output restart initialization of a subroutine e g while in the spectrometer operation mode program will return the operator to the first line of the program CURRENT POSITION JYA8P AN CC DL DR EN FP PL PR RG TB Cti X eliminates a string of instructions in the RT 11 text editor The Analytical Method Theoretical Aspects The analytical signal for any spectroscopic technique is generally made up of various cont
273. f manganese Clays and shales contain manganese in amounts similar to ig neous rocks Manganese carbonate rocks are variable ranging from manganese poor chalk and limestones to the man ganese rich ankeritic carbonates Safety advisory Exercise extreme care when using any acids and fluxes required for sample dissolution Their use should only be attempted after the appropriate MSDS sheets have been read and the safe handling and first aid procedures understood Acids should only be handled in a fumehood designated for their use and proper protective equipment worn Proper ventilation is required when handling fluxes which create a dust control problem 2 Before operating an atomic absorption spectrophotometer ensure that the instructions found in the manufacturer s operator manual are understood 3 Cylinders of compressed gas used as fuel and oxidant for flame atomic absorption spectrometry must be securely fastened and have the proper regulator Ensure that the system has no leaks and the gas hoses are in good condition Review the section on compressed gases found in the Geos cience Laboratories Safety Manual 4 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual Apparatus Varian AA 775 Nalgene ware 250 ml beakers 100 ml 200 ml volumetric flasks 500 ml graduated cylinders Porcelain crucibles Coors Hi
274. ferred to a 10 X 75 mm test tube Bibliography Hall G E M Vaive J E and Ballantyne S B 1986 Field and Laboratory Procedures for Determining Gold in Natural Waters Relative Merits of Precon centrations with Activated Charcoal Journal of Geochemical Exploration Vol 26 pp 191 202 McHugh J B 1984 Gold in Natural Water A Method of Determination by Solvent Extraction and Electrothermal Atomization Journal of Geochemical Exploration Vol 20 pp 303 310 EA22 3 DETERMINATION OF FLUORIDE Flouride AUTOMATED COLORIMETRIC METHOD Introduction The crustal abundance of fluorine is about 0 08 Fluorine has an ionic radius just slightly smaller than oxygen and as a result can substitute for oxygen in oxy minerals if valency compensations are allowed In some hydrous minerals such as amphiboles mica and apatite the replacement is quite easy Fluorine also occurs in the following minerals fluorite CaF topaz Al F SiO villiaumite NaF amblygonite LiAIFPO This automated procedure for the determination of fluoride in fused rock solution samples is based upon the distillation of hydrogen fluoride and subsequent reaction of the distillate with alizarin fluorine blue lan thanum reagent to form a lilac blue complex which is measured colorimetrically at 620 nm The fusion and distillation processes are represented by the following chemical equations CaF 2NaOH 2NaF Ca OH 2NaF 50 d
275. ffrac tometer using the spring clip to hold it The sample should be right up against the aluminum block above the spring clip for it to be evenly illuminated by the X ray beam IMPORTANT turn the water cooler on The diffractometer will have been set up by the Philips service engineer The settings for the detector and measuring circuits are stand ard and are given in the manual They do not need to be changed in ordinary operation Tum the mains power on The diffractometer arm should zero itself if not turn it off and on again until it does so Tum on the power to the X ray tube The voltage and current dials should be at zero or else the safety device will not allow the tube to turned on Increase the voltage gradually to 40 kV and then the current to 20 mA These are the standard settings and cover most types of analysis Check that the divergence and receiving slits are the 1 slits Set the 20 ranges on the dials the usual range is 5 to 70 20 Set the minimum position at the lower angle and advance the diffractometer arm to it before opening the shutter or else the beam will shine directly into the detector and may damage it Tum the chart recorder on and advance the paper until the pen is at a major division The chart drive is set at 2 cm per minute in normal operation Open the shutter and press the auto matic start button to begin the scan The scan rate is set at 2 20 per minute When the scan is ov
276. for blank 1000 100 sample wt 2 EA14 3 Total Fe Quality Control The determination limit is 0 296 as Fe using a 1 0 g sample Anestimate of precision at 95 confidence limit 20 at mid range value 5 is 0 2 absolute Accuracy is similar to precision for this method Productivity A technician should be able to complete 15 determina tions per day Additional Notes l Samples high in sulphur should be roasted first in Vycor brand glass crucibles 30 ml in a furnace at 650 C for 3 hours or preferably overnight Then transfer the powder from the crucible to the teflon beaker Rinse the crucible with several portions of distilled water and finally with in the teflon beaker Potassium permanganate is a volumetric oxidizing agent which is used for all ferrous and ferric iron determinations Its proper preparation and stand ardization is essential for accurate analysis 5 Fe 5 Fe 5 5e MnO 8H Mn 4 HO The freshly prepared KMnO solution is allowed to stand overnight to allow it to react with con taminants such as dust organic compounds and other oxidizable substances The KMnO solution is filtered to separate MnO The presence of MnO accelerates the decompos tion of KMnO in solution autocatalytic process 2MnO 4H Brown 2MnO 2H O Glass wool is used since filter paper reacts with KMnO to yield MnO Stannous chloride is added to redu
277. for sample analysis Example of typical routine run protocols maximum number of samples for a batch of samples is 50 a Warm up solutions Do not enter sample ID s for these samples to avoid saving data on disk This can be achieved by simply hitting the RETURN key b Recalibration standards if restandardization is necessary and requested as the mode These ID should begin with where must cor respond to a LOW or HIGH standard as defined in the Table routine c Rinse 10 HNO4 Normally sample ID is not entered so as not to store data on disk d Blank solution 10 The sample ID has to begin with the letters BLK if blank subtraction is requested as the mode All samples following this BLK will be automatically blank corrected e Check solution normally its ID is CK f 10 15 routine samples g Check solution h 10 15 routine samples if spaces are available i Check solution if spaces are available check samples check samples check and so on 10 2 reference standards and or calibration stand ards 4 7 Enter CNCODFBSSD see JY48P software manual for explanations 4 7 2 Enter XX where XX of samples maxi mum of samples is 50 4 7 3 Enter the sample identifiers according to the protocol required by the data reduction software programmes Refer to the JY48P Software manual 4 7 4 When all sample ID s have been entered and at the re
278. frequently reveal quite diagnostic colours e g yellow in chal copyrite Nonmetallics display a greater variety of colour Streak Streak is the colour of the powdered mineral It is usually obtained by rubbing the mineral over an un glazed porcelain streak plate Metallic minerals produce quite distinctive streaks Crystal Habit Crystals vary considerably in shape depending on rates of growth impurities present during growth and the nature of the host Nevertheless some mineral phases are often characterised by particular shapes called crystal habits Well known terms are fibrous acicular needle like columnar tabular scaly and micaceous In addition form names are often used such as cubic prismatic pyramidal etc Cleavage fracture and parting Many crystals break along smooth planes which are parallel to possible crystal faces Such planes are called cleavage planes Cleavages are repeated by the symmetry of the crystal inexactly the same way on all faces A cleavage may often be described as perfect good distinct imperfect or poor depending on its development Fracture refers to the shape of surfaces formed by breaking a crystal in a direction other than the cleavage Fracture may be conchoidal even uneven or hackly MS8 1 Mineratiiaenigyicanon Twinned crystals A twinned crystal is formed of two or more individuals of the same mineral joined together according to a defined law They may be j
279. from an empty disk an empty parameter bank and no data bank Tum computer on MCR X14 as outlined in EA16 Select the appropriate communications i e terminal at printer etc The system should be in automatic mode indicated by cursor A Creation of the Databank MAJORS Enter WDB MAJORS B Creation of the Parameter bank PB The first information to be entered in the PB are the measuring conditions for each of channel or analyte element This can be done in either manual or automatic mode The example shows the assembly of the iron channel Enter at the cursor ACH Assemble CHannel The system will respond with NAME F Enter the required symbol e g type FE as above The system will respond with LINE KA R default Ka K alpha Enter R to select K alpha default value The system will respond with FLT NO R filter Y NO default NO Enter R to select no filter The system will respond with COL F C collimator fine F or coarse C Enter C to select coarse The system will respond with EA6 16 Majors XRF DET FS R detector F flow S scintillation FS tandem Enter R to select tandem The system will respond with XTL 1 R LiF200 default Enter R to select the LiF200 crystal The system will respond with ORD 1 R order of line Enter R to select the first order The system will respond with UPL 0 8 upper limit on window of
280. ful in matching the pattern The most useful data would be the chemistry of the mineral as the minerals are listed chemically Indexing a pattern using the Hanawalt system the following steps may be used 2 1 Identify the three strongest lines 2 2 Tumto the section in the search manual cover ing the strongest line 2 3 Taking the second strongest line scan the second column in the section and match it 2 4 Looking at the first and third lines in this area attempt to match the unknown using the five other lines forconfirmation and any additional information that is known about the sample The d spacings may not agree exactly because of instrumental problems or solid solution but the overall pattern should be the same Note too that variations in the intensity of some lines may occur because of a coarse sample or preferred orientation 2 5 For a proper match the JCPDS card should be examined and all the peaks indexed with ref erence to the card XRD For mixtures of several minerals the procedure is much more complex as the ordering of intensities is difficult In most rock samples however there are recognizable minerals and their peaks e g quartz at 26 6 20 The full pattem of each mineral is subtracted and the search is then done on the residual pattern Identification of trace phases in such mixtures can be almost impossible particularly if these minerals are strong absorbers of the particular radiation used
281. g Fe 2 Hedenbergite Cake Mg The remainder of Mg Fe to the original minus Ca of Wollastonite is calculated as Hypersthene There is no change in total Si in the above 3 steps because the minerals have been converted to other minerals with the same silicon content The necessary amounts of Hypersthene if any are converted to Olivine according to the equation 4HY 301 1Q Norms 18 If these still is not enough Si in the analysis Albite is turned into Nepheline according to the equation SAB 3Ne 2Q 19 If the analysis is very low in Si Orthoclase is in part or wholly converted into Leucite SOR 4LC 1Q 20 In rare cases there is not even enough Si to form Leucite Then Kaliophilite is formed 4LC 3KP 1Q Bibliography Barth T F W Calculations and Classification in Theorectical Petrology John Wiley and Sons New York 1952 pp 76 82 Irvine T N and Baragar W R A A Guide to the Chemical Classification of the Common Volcanic Rocks Canadian Journal of Earth Sciences Vol 8 1971 pp 525 526 Johannsen A Calculation of the Norm in a Descrip tive Petrography of the Igneous Rocks Vol 1 1950 pp 88 92 MS15 3 Alknorm ALKNORM FOR FELDSPATHOIDAL AND MELILITIC IGNEOUS ROCKS Introduction Chayes and Yoder 1971 have underlined some of the inadequacies of the CIPW normative system when dealing with feldspathoidal and melilite bearing lavas King 1965
282. g the tygon tubes connected to the air inlet line of the distillation apparatus Figure F2 briefly into 1 NaJEDTA solution A quantity of the wash fluid will be swept through the teflon coil and will remove deposited material When all particulate matter is removed from the coil wash briefly with distilled water several times Pump tubes should be replaced after 200 working hours or prior to that if they become inflexible or flattened They should always be left in a relaxed position when not in use The nickel crucible should be cleaned as soon as possible after use The most effective way is to place them in hot 3N HCI for 10 15 min transfer to a 596 NaOH solution and boil for half an hour wash with Alconox solution rinse with tap water and finally rinse with distilled water uality control The optimum working range for the analytical system is 0 2 to 2 0 ug F ml which is equivalent to 200 2000 ppm in rock The determination limit is 40 ppm in rock The precision expressed at the 95 confidence limit 20 is 10 relative e g 400 ppm 40 ppm The accuracy is comparable to the precision based on data collected from standard reference materials Productivity A technician should be able to complete 10 deter minations per day Additional notes 1 Do not allow the platen to remain down on the pump tubes when the pump in not operating The fixed pressure will damage the pump tubes 2 The vacuum gauge read
283. g the wet sensor 2 Calibration of the system 2 1 The main control unit is switched on at the back and allowed to warm up for half an hour before calibration 22 A calibration must be established for the 32 channels of this system for both the wet and dry sensor Once this calibration is completed it can be used repeatedly the only precaution routinely needed is to check that the channel thresholds have not drifted away from those values listed in the original calibration When switching from the wet to the dry sensing modes it is necessary to completely change these settings To view the thresholds of each channel the special function key is used and the number of the channel is entered on the keypad e g 01 for channel number 1 etc 2 3 The system is configured to use calibration No 3 for the dry sensor and No 2 for the wet sensor A linear relationship exists between the threshold voltage of the sensor and the size of the particle from which the millivoltage corresponding to a particular size can be es tablished These thresholds are kept constant for every analysis performed on the particular sensor 3 Operation of the computer and processor 3 1 The instrument runs under the control of an IBM PC AT clone equipped with an EGA card monitor math co processor and an extra serial port The system runs a program called PDAS directly from the DOS COMMAND shell Operations are explained directly by means of hel
284. ge of the mineral grain Edges of grains which are wedge shaped show a range of interference colours from Ist order grey at the thin edge inwards towards progressively higher order colours By counting the colour rings the order of the colour in the main part of the mineral section can be determined In thin sections which are 30 microns thick quartz may be used as a control on the birefringence of other phases as it invariably shows first order pale yellow 3 1 Fast and slow direction the use of acces sory sensitive tint plates The 1 wavelength plate made of gypsum or quartz has the thickness and orientation to produce 1st order pink This plate has two vibration directions in the 45 position which are marked on the plate as fast and or slow The accessory plates are used to increase the equivalent thickness of the thin section and to compen sate for the wavelength difference produced by a mineral MS9 2 This is performed by putting the mineral section in extinction Figure OM2 thus producing two vibration directions E W and N S The stage is then rotated through 45 noting whether clockwise or anticlockwise to determine the colour produced by the mineral Insertion of the plate is accompanied by a change in the colour If retardation Occurs i e the interference colour increases then the slow direction of the plate is parallel to the slow direction of the mineral If compensation occurs i e the interference colour d
285. ges 51 2 to 1 5 and sub mitted for geochemical analysis for the elements Ni Cu Co Cr and S Nickel and sulphur values are critical in the determination of the charge composition Elevated copper values may indicate low concentrations of some of the PGE High chrome samples may indicate the presence of chromite which will interfere with the precious metal recovery 3 1 2 Samples are prepared in duplicate such that a 24 34 g button is prepared which contains ca 16 g Ni 10 g S and all noble elements The charge composition is calculated in four stages MS14 4 STAGE 1 If the pulp contains gt 20 Wt S then the sample size is selected so that the button contains only 10 g sulphur i e if the sample contains 30 S then the amount of pulp used is 1000 30 z 33 3g If 1 Wt S lt 20 Wt 50 g of pulp is used and sufficient S is added so that the button will contain 10 g sulphur i e Wt S added 10g E EE If the S content is less than 1 Wt only 40 g of sample is used and 10 g of S is added STAGE 2 The nickel content of the button should be ca 16 g To achieve this the amount of Ni added is given by Wt Ni added g Wt Ni in sample g x Wt sample g 1985 100 3 Silica is added to the charge If S 8 Wt then no silica is added If 8 Wt lt S lt 15 Wt then 5 g of silica is added If 15 Wt lt S lt 30 Wt then 10 g of silica is added If 30 Wt lt S
286. gh Form 30 ml Graphite crucibles 32x29 mm 9 ml Magnetic stirrers with teflon stirring bars Thermolyne Muffle Furnace Silica tray Crucible tongs Filtering funnels Whatman 41 filtering paper 12 5 cm Reagents Lithium metaborate anhydrous LiBO Hydrofluoric acid HF 48 Strontium nitrate Sr NO4 Boric acid crystal Silica powder SiO Graphite powder Method The method consists of the following techniques 1 Samples are fused with lithium metaborate and dissolved using HF 2 Analyte concentrations are measured by atomic absorption spectrometry 3 Calculation of results using calibration curves produced from reference materials NOTE For routine work in house reference materials are used In special cases certified reference materials may be used These reference solu tions may be store in polypropylene bottles and used for a number of sample batches Procedures 1 Reagent preparation 1 1 Hydrofluoric acid 10 stock solution Add 125 ml of 48 HF to 375 mi of distilled water in a 500 ml nalgene graduated cylinder Store in a clean and empty polypropylene supplier container 1 2 30 000 ppm Strontium Buffer Dissolve 72 0 g of strontium nitrate in distilled water and make to 1 liter volume with distilled water see Note 1 2 Sample Decomposition 2 1 Weigh 0 200 g of sample into a porcelain crucible see Note 2 2 2 Add 1 0 g of lithium metaborate
287. ghtly otherwise a vacuum is produced and air bubbles end up in the dispensing barrel Occasionally un screw the cap to avoid this EA19 3 Traces ICP MS 5 Maintenance Work areas in and near the fumehood and work bench should be cleaned whenever required The fumehood has internal plumbing for washing down the stacks and the inaccessible walls of the fumehood This should be used at the finish of each batch Bytac protec tive Teflon covering has been installed and should be wet mopped between batches EA19 4 THE ELAN 250 Introduction This documentis intended for use as a bench procedure for the routine operation of the Sciex 250 Elan Induc tively Coupled Plasma Mass spectrometer Method The instrumental method consists of the following procedures Instrument start up Mass calibration Signal optimization Setting up the run Performing analysis Analyzing the run Performing calculations Instrument shutdown normal operation Instrument shutdown emergency procedure ood o Gr RU b rS Procedures 1 Instrument Start up Become familiar with the location of all switches and controls on the instrument before operation Many of the steps require a sequence to be performed quickly Ifthings go wrong don t panic but move immediately If you are not confident about any operation do not start the procedure or abort the procedure and seek assis tance 1 1 1 The outer sleeve of the torch should ext
288. gression analysis yielded a linear graph with slope close to unity and intercept close to zero This indicates that the two methods are equivalent and supports the contention that significant sources of determinate error are not biasing the results EA12 2 Accuracy Comparison with Established Method Comparison of LECO RMC 100 with Gravimetric Procedure H20 Sample Leco H20 Gravimetric 20 104 3 13 3 06 117 4 40 4 14 118 4 79 4 61 119A 4 16 4 00 119B 0 90 0 77 121 2 52 2 60 124 1 55 1 54 125 3 21 3 13 132 1 70 1 58 158 1 80 1 76 182 2 07 2 00 199 3 99 3 76 200 2 80 2 82 01 3 09 3 06 22 2 79 2 61 214 2 86 2 71 215 2 74 2 90 218 2 71 2 56 219 3 21 2 91 104D 3 32 3 16 219D 3 07 3 03 Regression Output Constant 0 039 Std Err of Y Est 0 103 R Squared 0 988 No of Observations 21 Degrees of Freedom 19 0 952 0 024 X Coefficient s Std Err of Coef These data are plotted on the accompanying graph Accuracy was further checked by analyzing standard reference materials Accuracy Typical Analysis of SRM STD H20 HO Lit Value H20 NIM L 0 19 2 24 2 31 NIM L 026 2 24 2 31 NIM L 027 228 2 31 MRB 10 0 46 11 74 11 7 MRB 10 0 45 11 85 11 7 Note Accuracy statements do not apply to as samples absorb variable amounts of this water Results indicate good agreement between observed and expected H O values Factors such as frequency of standardization stability of standards and personal
289. h s crust The con centration of aluminium depends on the magmatic sequence of crystallization The aluminium content in rocks is typically from 10 to 25 percent Aluminium content decrease in order dolerite basalt gabbro gt andesite diorite gt tonalite granodiorite gt granite rhyolite Some of the more important minerals of aluminium do not crystallize in the main stages of silicate differen tiation but appear with rare element concentration at the pegmatite and other late stages of rock emplace ment These include beryl spodumene topaz and cryolite Andalusite sillimanite and kyanite may con tain up to 60 percent Al O3 Rarer aluminium minerals include corundum chrysoberyl turquoise alum and alunite The main sources of aluminium metal are the bauxite and laterite ores which result from weathering leaving aluminium as an insoluble residue Iron Iron is the fourth most abundant element com prising about 5 percent of the earth s crust Basic rocks may contain 30 to 40 percent iron as FeO while many acidic rocks contain as little as 1 percent total iron Ferric iron is frequently associated with aluminium and ferrous iron with magnesium Sulphide minerals such as pyrite pyrrhotite and chal copyrite are common Iron carbonate minerals are siderite or chalybite FeCO and ankerite which is a mixed carbonate of iron calcium and magnesium Calcium Calcium ranks fifth in the orderof elemental abundance
290. he high temperature block 1 set at 180 C see Note 2 The samples will remain at this posi tion for 17 hours If sample 1 rack 2 sample 31 is available the robot will process this sample as in steps 2 1 and 2 2 This sample is then placed in the vacated position 1 of the low temperature hot block Time required for this operation is approximately 3 minutes see Note 3 Operations 2 5 and 2 6 are repeated until all samples originally in the low temperature hot block are now in the first high temperature block and all samples from rack 2 are in the low temperature block The robot will remove samples from the low temperature block to the second high tempera ture block after 3 hours 30 minutes has elapsed for each sample It will remain in a rest posi tion for the full 6 1 2 minutes between samples After sample 1 has been in the high tempera ture hot block for 17 hours it is transferred to the acid dispensing station where 2 ml of HNO are added a 1 minute pause introduced 0 5 ml of is added and after a 1 1 2 minutes pause and 0 5 ml of distilled water is added Sample 1 is placed in the low temperature hot block for 8 1 2 minutes see Note 4 Time will allow sample 2 to be processed as in steps 2 9 and 2 10 Robot initiates next step for sample 1 see Note 4 Sample 1 is transferred to dispensing station where 22 5 ml of distilled water are added to the vessel Sample 1 is transferred to t
291. he capping station vessel is capped and placed in its home posi tion Robot has time to process sample 3 as in steps 2 9 and 2 10 EA2 3 sample Lissotution 2 16 2 17 2 18 Robot must now process sample 2 as in steps 2 13 and 2 14 Samples are processed in the above sequence until all vessels have been capped and placed in their home positions see Note 5 This completes the decomposition steps handled by the robotic system Capped vessels are mixed thoroughly and Split into two components for distribution to AAS and or ICP OES measurement see Note 6 NOTES 1 The rate limiting time for this initial step is 6 1 2 minutes Sample 2 will not be processed until this time has elapsed The robot will note the time remaining of the 6 1 2 minutes before sample 2 rack 1 needs to be removed to the high temperature block If suffi cient time is available to initiate another step in the program before this time has elapsed it will do so see step 2 6 Sample 32 cannot be processed before 2 be cause of insufficient time see Note 2 and because only one low temperature hot block is available and position 2 is still being occupied by sample 2 This 8 1 2 minutes is another rate limiting time Anothersample will be processed if sufficient time is available before the next step for sample 1 needs to be initiated Time elapsed for first sample to complete the process is 20 5 hours for a batch of 48 s
292. he determination limit is 2 ppb Au in rock and 1 ppb for Pt or Pd The estimated precision at 95 confidence limit 20 for a value at 10 times the determination limit is 5 ppb for Au and 3 ppb for Pt and Pd relative Accuracy is comparable to precision based on data collected from standard reference materials Productivity A technician should be able to complete 20 samples per day if there are no usually high concentrations Additional Notes 1 Standards must be prepared with the same acid concentrations contained in the samples that is nitric acid 1 15 and hydrochloric 1 15 2 dilutions must be made with an acid mixture containing these same concentrations 3 Standards should be prepared every 2 weeks and stored in polypropylene containers 4 Concentrations of 50 ppm of platinum palladium and silver have no interfering effect on a gold absorbance represented by 0 2 ppm 5 Concentrations of 50 ppm silver gold and platinum have no interferring effecton a palladium absorbance represented by 0 2 ppm 6 The following observations on the absorbance of a 0 2 ppm Pt solution are 50 ppm Ag reduced the absorbance by 5 50 ppm Au and 5 ppm Pd had no effect and 50 ppm Pd reduced the peak absorbance by 10 EA21 3 Au Ft Fa Bibliography Analytical Methods for Atomic Absorption Spectros copy Using the HGA Graphite Furnace Revised March 1977 Perkin Elmer Corporation Norwalk Conne
293. he predicted ignition loss of the 1 500 g subsample of rock powder This ensures that a 100 analysis total still refers to the whole rock sample i e total bead weight remains the same Additional flux weight 2 1 500 x LOI sample Analytical results are reported as obtained from the instrument CASE 2 LOI 10 ADD MORE SAMPLE If rock LOI is greater than 10 it is unlikely that the sample is a silicate rock and that a good analysis will result If the analysis is carried out in spite of this then the weight of sample is increased such that the ignited sample weight in the bead is equal to 1 500 g Wt sample 1 500 x 100 100 LOI sample The final analysis total ca 100 will relate to the ignited sample Results must be factored to relate to the original sample All concentrations are multiplied by the correction factor Correction factor 100 LOI sample 100 All LOI corrections are noted on the LOI sheet For CASE 1 the additional flux weight is noted in pencil For CASE 2 the total weight of rock powder required is noted in red Example of LOI corrections Base finished weight of bead assuming 0 sample LOD 1 500 7 326 0 887 9 713 g Percentage of rock powder in bead 1 500 9 713 x 100 15 44 Example 1 Sample 100 SiO LOI 0 SiO in bead 15 44 equivalent to 100 rock Example 2 Sample 96 SiO LOI 4 No Correction Wt Si in 1 500 g sample 0 96 x 1 500 1 440 g Wt finished b
294. he sample is deter mined by simple ratio with the peak heights of the calibration standards The above equation is used to calculate the result for the sample EA17 3 Traces AA 6 Reporting All results are reported on appropriate Trace Element Analysis Forms See the manual Processing of Whole Rock Chemical Data Ontario Geological Sur vey for all details Normally the trace element forms will be computer generated and complete with sample numbers geologist S name and job number If these are not available the appropriate identifying data and correctly sequenced sample numbers will be entered by the Laboratories staff doing the analysis Correctly se quenced sample numbers refer to the order as written in the Geoscience Laboratories Job Sheet There are five column spaces for each analytical result The first four are for the numerical value of the determined concentration the fifth for the unit of concentration Concentration may be entered as percent P ppm M or ppb B The use of a decimal point is allowed in any of the first four columns A blank in the unit column is assumed to be ppm M Amounts less than the detection limit will be recorded as the detection limit preceded by a minus sign e g 5 indicates a value below the detection limit of 5 N D and are not allowed The Trace Form 1 is used to report the T1 elements Co Cr Cu Ni Pb Zn Ba Li and Ag The Trace Form 5 is used to report Cd The
295. he sample is placed in position the name is typed at the terminal and upon receiving a carriage return the port closes and the system puts 2 into the loading position When all the positions specified earlier are filled the system begins to measure X ray intensities according to MP1 Intensities are stored automatically under file MAJORS RO1 XXXXXX RYY where XXXXXX file name YY Measurement Program Number Additional reference materials can be run in a similar manner Entering Concentration Data Once all intensities have been measured the intensity file is opened and the accepted literature concentration values are carefully inserted into the file Every time the operator wishes to manipulate a data file it must be opened using the instruction illustrated below OPF MAJORS RO1 The system responds with file information ending message with cursor ACD Assemble concentration data The system then asks the operator to input concentration data of the elements in the order specified in the MP LP set for the standards in the order stored in the regression data file The Philips software is set up generally to handle concentration units in percentages Trace element values can be entered for convenience as ppm 1000 Thus for example a value of 125 ppm would be entered as 0 125 Care must be taken with interpretation and reporting of data If the operator wishes to stop entry at any point he she types R slash retum One can re
296. he stock standard solution with distilled water The standard solutions should contain 4 g of sodium hydoxide and 24 ml 1 1 perchloric acid per 100 ml in order to match the amounts of these substances used in alkali fusion of the rock samples Store in polyethylene bottles Diluent Dilute 25 ml of 100 ug F ml stock standard solution to 1 liter with distilled water and mix 3 Fusion and sample decomposition 3 1 3 2 3 3 3 4 Es 3 6 3 7 3 8 Weigh out 0 050 g of rock sample and transfer into a 40 ml nickel crucible Add 0 2 g of sodium hydroxide pellets ap proximately 12 and fuse the sample in a muf fle furnace at 600 C for 5 minutes Remove the crucible and swirl to suspend all particulate matter Cool and dissolve the melt with water by heat ing the contents on a hot plate at low heat for half an hour Transfer the contents into a plastic beaker graduated at 50 ml Rinse the crucible with distilled water and add to the beaker Add 12 ml 1 1 perchloric acid to dissolve the suspended particulates Dilute the sample to 50 ml with distilled water Mix the solution thoroughly with a plastic stir ring rod The solution is ready for the determination of fluoride by an AutoAnalyzer One fusion blank is normally prepared for each 12 samples 4 Measurement of F concentration 4 1 Start Up Procedure for AutoAnalyzer l Inspecttubing connections between distillation apparatus sampler
297. her approach can be considered It is possible to assign an arbitrary cut off point below which interferences can be ignored As a first approximation x C 0 5 PDL A the contribution can be ignored with minor contribu tion to total analytical error In the Nb example 0 5 PDL A 0 025 and all but the Al could be ignored Mg is a borderline case and the correction is included The subsequent partially corrected Nb value would be 0 956 ppm total error 3 1 RSD To reduce the error the cut off value could be set at an even lower fraction of the analyte PDL A if desired From this limiting criterion it is possible to estimate critical interferent concentrations for any analyte based on the PDL A and interference coefficient xC lt PDL A 2 C crit m t Thus for the Nb example PDL A 0 05 ppm solu tion 5 ppm rock the critical concentrations for a series of potential interferences are listed below Element Xi Ci crit sol Ci crit rock Fe 0 000027 925 ppm 9 25 Mg 0 00012 210 2 1 Ca 0 000030 830 8 3 Al 0 00022 114 11 Ti 0 00018 140 14 Ni 0 00018 140 14 V 0 0 0 25 25 ppm Cu 0 00021 120 12 Nd 0 0012 21 2100 ppm 0 2 Traces Summary In the determination of elements by ICP OES the potential interferences can be summarized into four principal categories MajorInterferent Major Analyte Major Interferent Trace Analyte Trace Interferent Major Analyte T
298. hings through the filter wash the precipitate and paper five times with this wash solution adding all washings to the filtrate Reserve the filtrate for subsequent examination Magnesium re precipitation Dissolve the precipitate in the beaker in the minimum volume of hot 5 and rinse down the walls of the beaker Cover and heat to near the boiling point and pour the contents of the beaker through the filter catching the filtrate in a 250 ml beaker Wash the paper and funnel with a small amount of hot 5 raise the inside flap of the paper and wash behind it to dissolve any trapped precipitate then with water and remove and discard the paper Wash the inside of the funnel once with 5 and then with distilled water rinse the tip of the funnel into the solution also To the filtrate in a 250 ml beaker and having a volume of about 100 ml add approximately 0 1 g NH4HPO and cool the solution to about 10 C Add pure aqueous ammonia dropwise until a precipitate forms allow this to settle and con tinue to alternate addition of reagent and set tling of the precipitate until precipitation is complete as evidenced by no formation of a precipiate on the addition of a drop of aqueous ammonia Add 10 ml of aqueous ammonia and allow to stand overnight Examine the first filtrate for signs of precipitate If none discard the solution if a small precipitate is present decant about three Majors
299. his way for the CHK2 solution can be used to assess accuracy Determination for a wider range of interna tional reference materials and a larger number of analytes has been carried out in press For research grade jobs appropriate reference materials are run e g SY 2 MRG 1 AC E Accuracy is about 5 uality assurance The digestion and instrument control data for a par ticular batch are compared with the above values by calculating the number of standard deviations the con trol solution data differ from the mean These calcula tions are printed at the end of the interim report produced by the Apple concentration calibration cal culation software This interim report is filed along with the original bench sheets for the job The run number associated with the data is also included on the bench sheets The run numbers on a particular data disk are written on the disk label The run numbers on a particular data disk can also be identified by using the Apple utility program FIXRUNQUE With all this information data can be retrieved as required Productivity Ideally a technician should be able to complete about 60 solutions per day Data reduction and reporting are not included Additional Notes l If a clean sampler and skimmer are being used a 1000 ppm Ca solution must be nebulized to protect them This Ca standard must be prepared from the pure Johnson Matthey CaCO powder The ap propriate weight of
300. hod outlined in this docu ment has the advantage of being relatively rapid and simple Safety Advisory 1 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17 2 Sulphuric acid hydrochloric acid phosphoric acid and potassium permanganate are corrosive sub stances 3 Mercuric chloride is toxic 4 Boricacidcancause skin irritation and may induce an allergic reaction Avoid contact with any of these materials Exercise caution when handling these materials Wear protective clothing and use eye protection Method The method consists of the following techniques 1 Sample decomposition using wet chemical proce dures 2 Volumetric analysis using a titrimetric procedure employing potassium permanganate 3 Calculation of the result Apparatus 30 ml platinum crucible with tight fitting lid 25 ml polyethylene graduated cylinder glass burets 10 ml and 50 ml glass beakers 600 ml 1 liter 2 liter florence flask 1 liter tongs for platinum crucible teflon beakers 100 ml and 250 ml glass wool lOliter container for standardized potassium per manganate EA15 1 Ferrous Reagents boric acid crystals concentrated sulphuric acid concentrated hydrofluoric acid potassium permanganate crystals NBS 29A Iron Ore Standard 69 54 Fe stannous chloride SnCl 2H O h
301. hould be even and slow The die must be placed centrally and must be level Failure to do so can result in uneven loading and mechanical failure A Philips PW1400 wavelength dispersive X ray fluorescence spectrometer is used to nondestructively analyze the matrix modified samples A general description on how to use the Philips PW1400 X ray spectrometer is presented on page EA6 1 and the measurement of trace element analyte concentrations is documented starting on page EA16 1 2 Calculation of Final Results All necessary calculations are performed automat ically by the system computer Major element analysis results are entered on a Major 1 and Major 2 Analysis Worksheet The Major 1 M1 package includes the 10 major components LOI and a TOTAL C S data are normally obtained for M1 samples The S is required to prepare the sample roasting etc The Major 2 M2 package includes C S H O FeO and LOI in addition to the 10 major components The LOI is not included in the TOTAL but is useful for comparing the total volatile content In this case the LOI is corrected to account for oxidation of ferrous ion Majors XRF TABLE MXRF 3 RANGE AND PRECISION FOR MAJOR ELEMENT PACKAGES Silicate Rocks Carbonate Rocks Component Range Precision Range Precision 102 30 80 0 8 0 5 0 2 Al203 0 20 0 3 0 3 0 1 Fe203 0 15 0 2 0 4 0 02 MgO 0 20 0 3 0 22 0 2 Na20 0 10 0 5 0 1 0 4 K20 O0 10 0 15 0 1 0 02
302. ht hand corner of the video terminal EA19 10 6 1 5 6 1 6 NOTE 6 1 9 6 1 10 NOTE Activate the computer back lower left hand corner After about 30 seconds the display will show the Elan Apple main menu Select option 1 This will initiate the intensity data collection program Respond to the first prompt by entering the appropriate parameter set name The program will prompt for 1 Run ID 2 Autosampler y n 3 Number of tubes in the run Enter this information following each entry with R At this point the screen will display the or dinal number associated with the sample tube position in the run The record number into which the data will be written in the Apple disk file will also be displayed The Apple II keyboard will be live at this time The Apple cannot distinguish between a keyboard entry from data comming from the Elan Consequently inadvertent keyboard entry will corrupt the data and probably cause termination of the program So don t touch the Apple keyboard After information has been entered return to the Elan and press GI to begin the analysis The program running on the Apple II will monitor the data coming from the Elan Upon completion of the set of samples the Elan will return to the first screen of the QUANT program The Apple will require additional input Respond to the following Apple prompts Do more analysis using the same parameter set I
303. hylene container to desorb Au from the container walls Allow to stand for 2 days with occasional shaking Filter one liter of water sample using a What man No 40 filter paper Evaporate the water sample in aliquots on a hot plate using a 400 ml beaker It will take about 15 hours to evaporate a one liter sample to near dryness Do not allow the sample to boil par ticularily toward the end of the evaporation Add 7 ml 0 596 bromine in hydrobromic acid from a burette Warm gently and allow to stand for 15 minutes Transfer the solution to a clean 125 ml separatory funnel Rinse the beaker with 7 ml distilled water added from a burette and add the rinsings to the separatory funnel 3 8 3 9 3 10 3 12 3 13 3 14 Add 2 ml MIBK from a 10 ml microburette to the separatory funnel Shake for five minutes Allow layers to separate about 15 minutes and drain off the aqueous layer centrifuge if emulsion forms Add 8 m10 1N hydrobromic acid solution from a burette Shake for one minute allow to stand for 15 minutes and drain off aqueous layer Transfer the MIBK extractant solution to a test tube using a disposable pipette Determine absorbance by graphite furnace AAS technique Prepare 5 10 and 20 ng standards daily by pipetting 1 2 and 4 ml of 5 ng ml Au in 0 5 Br HBr solution into three separatory funnels followed by 6 5 and 3 ml of 0 5 solution respectively Add 7 ml of
304. iate repeat the FeO determination If a series of beads are giving problems it may be useful to check for errors in sample identification or mix up in samples When all else fails the conflicting elements can be analyzed by classical methods in the chemistry sub section Majors XRF 2 Erratic analytical results associated with the XRF spectrometer Persistent problems should be brought to the attention of the Supervisor and may require a service call 3 Fused discs containing low 10 30 silica will produce poor results below the calibration range of the method Powder pellets are generally good for silica determinations in the range O 1056 Thus silica in the range 10 30 is difficult to determine Classical analytical methods may be used for samples containing this level of silica Bibliography Mason B Principles of Geochemistry Wiley and Sons Ltd New York 3rd Edition 1966 329 pages Nockolds S R Average Chemical Composition of Some Igneous Rocks Bull Geol Soc America V 65 Read H H and Watson J Introduction to Geology Vol 1 Principles MacMillian 1962 EA6 13 Majors XRF APPENDIX A LOI CORRECTIONS When the sample has substantial loss on ignition the weights sample or must be adjusted to produce a finished bead of the required weight CASE 1 LOI 2 10 ADD MORE FLUX When the LOI of the rock powder is 2296 but 10 additional flux is added equal in weight to t
305. ifferent types of rocks provides a method of classification by quantitatively studying and com paring the norms of unknown rocks The elements used in the calculations are usually ex pressed in the oxide form and are given in Table NORM1 The CIPW norms weight norms are calcu lated by assigning amounts of the molecular properties to a standard set of mineral molecules as outline in Table NORM2 The molecular properties are the weight percent of the elemental analysis divided by the molecular weight The percentage of each mineral molecule is then cal culated by multiplying the molecular amount of each constituent of each mineral by its molecular weight The Swiss mineralogist and petrographer Paul Niggli introduced an important change to the norm calcula tion by discarding the weight units and introducing the equivalent molecular unit These are based upon the number of cations in the mineral or oxide e g Ca0 Al 03 2Si0 5 formula has 5 cations 1 1 equal to a quantity of anorthite containing one cation Cation equations can thus be written easily e g 4En 3Fo 1Q 2 MgO Si02 2MgO SiO SiO In the norm calculations with Niggli s method the molecular proportions are abandoned in favor of cation proportions With this method all the elemental oxides constituents are reduced to one cation See Table NORM3 To calculate the cation proportions the weight percent is divided by the equivalent mole
306. ificates and or worksheets There are three programs that must be run to accomplish this task INFORM ELEFIL and WORCER This report describes the use of the programs The INFORM program sets up a client database file that can be easily updated with new information as required Each time TSPA samples are run new client information will be added to the database This file will appear on the system disk as DAT file In this report the symbol denotes a user supplied file name The ELEFIL program allows the user to select the elements of interest At the present time the TSPA program for the JY48 is fixed in this regard so this utility program need only be run once to create the necessary element data file If the number of elements in the JY48 TSPA program is changed this program must be run again The element identifier file is stored on the system disk as DAT The WORCER program is used to produce the signature ready certificates and or worksheets Procedures 1 Insert the system disk for the TSPA certificate and or worksheet into drive 1 NOTE The TSPA certificate and or worksheet program must be run on the system disks that have been formatted to maximize disk space Use ONLY these specially formatted disks to run the TSPA programs 2 Insert the disk that contains the data into drive 2 i e the original JY48 DAT TSPA files in percent concentrations format 3 Check the directory of the system disk and make sure the cli
307. ill depend on the flow rate of the sample through the instrument and the rate of delivery of sample vapor to the plasma physical conditions of the plasma e g temperature Because of the very high tempera ture of the argon plasma compared to that achieved by a gas oxidant flame in AAS chemical recom Traces ICP OES bination oxide formation is generally minimized and ionization and excitation efficiencies are ex pected to be high However the presence of rela tively high concentrations of sample elements in the plasma can affect these efficiencies The presence of large amounts of easily ionized species can upset the ion atom equilibrium The energy requirements for the processes may be high enough to lower plasma temperature and result in poorer efficiency of the processes The additional excitations may contribute to the background A single element in a solution will produce a series of emission lines at different wavelengths These result from the excitation of outershell valence electrons into unoccupied upper energy states orbitals The resulting atom ion energy state is unstable and the electrons lose the energy by returning to their original ground states The energy lost emitted will be equal to the difference between the upper and ground state energies and will appear as specific wavelengths of radiation These in turn can be dispersed by an optical device prism or grating and the level of emis sion measur
308. ily routine analysis a 100W 100ppm W b A 100 ppm Co Ni V Cu Sr 10 ppm Sc Y Mo c B 100 ppm Zn Ba Cr 10 ppm Nb Be Zr Ce d MN minor 500 ppm Mg 50 ppm e MJ major 1000 ppm Fe AL Ca 80 ppm Mn Ti f C 100 ppm Pb La Nd g Ta 100 ppm Ta To maintain optimal analytical precision the fol lowing procedures are recommended clean the torch clean and unclog nebulizer analyte profiles top and bottom should be check ed periodically ensure the wick for guiding the drain in the spray chamber is in the correct position Small fluctuations in the pressure within the spray cham ber substantially alter the emitted signal The drain bucket should be emptied periodically never allow it to get more than half full gas lines to the torch and nebulizer should be clamped with snapper hose clamps critical for good RSD periodically monitor the gas flow rate to ensure constant flow change the sample delivery tubings periodically and check the uptake rate 1 ml min distilled water there should be no cracks in any of the rotometers gas lines located inside the torch box left hand side Traces ICP OES APPENDIX A GENERATION OF T 2 FINAL REPORTS Introduction The T2FORM programs produce the final T 2 job report forms To do this three programs must be run in succession the programs T2CON JOBFIL and T2FORM The following describes how to use these programs The program T2CON crea
309. inally heat strongly with full flame until all fuming ceases This helps in removing the last traces of HF and converting sulphates of many ele ments into oxides Cool the dish and add about 5 ml of conc HCI 3 12 Evaporate to dryness on a low heat This helps in converting oxides to chlorides which are easily soluble in distilled water 3 13 Cool and add about 5 ml of conc HCl Leave it for about 1 2 minutes to react 3 14 Then add about 30 ml of distilled water and heat well until sample is in solution It takes approximately 45 minutes to one hour depend ing upon the nature of the sample 3 15 Filter into a 250 ml volumetric flask using a Whatman No 40 filter paper 3 16 Wash the platinum dish several times with small portions of hot distilled water using glass wash bottle and transfer all washings to the filter paper 3 17 Wash filter paper several times with small portions of hot distilled water using glass wash bottle 3 18 Finally add 2 5 ml of Li stock solution 1500 meq l and make to 250 ml with distilled water in a volumetric flask Now the solution is ready for measurement 4 Addition of reference Li stock solution 4 1 1 Preparation of Na and K standard solution for calibration Add 0 ml 1 25 ml 2 5 ml 5 0 ml and 7 5 ml and 10 0 ml from microburette 0 10 ml of 1000 ppm Na and K stock solution into 500 ml volumetric flasks 4 1 2 Add 5 ml using a 0 10 ml microburette of Li stoc
310. increased it is able to deflect minerals with weaker and weaker susceptibilities and thus separate minerals on the basis of their magnetic proper ties The range of magnetic susceptibility of various minerals is given by Rosenblum 1958 Flinter 1959 and Hutchison 1974 Note that the currents given by these authors are for the isodynamic separator the newer barrier separator uses much lower currents For ferromagnetic minerals the residual magnetic field is still too strong for successful separation of these minerals The Frantz low field control can be used to separate these minerals as it reverses the direction of the current to establish a hysteresis loop that reduces the magnetic field to zero When separating paramag netic minerals material is fed into the inner channel of the chute which has a side inclination such that gravitational forces push the feed into the other outer channel For diamagnetic separations this is reversed the feed is in the outer channel and the side inclination is toward the pole pieces Safety advisory 1 The high magnetic fields generated by the pole pieces may have a harmful effect on pacemakers and hearing aids These fields will also cause damage to watches calculators magnetic disks bank and security cards etc Method 1 Sample preparation the sample should be washed to remove fine powders which could alter the magnetic properties of the mineral to which it is adhering and also clog
311. ined with the tint plate Figure OM2 If 2V is 90 the mineral is neither positive nor negative If the isogyres remain in the field of view when the stage is rotated Figure OM2 the mineral is biaxial and the acute bisectrix is near vertical in the section Positive or negative character can be determined and 2V estimated when the isogyres are in the 45 position If the isogyres barely separate 2V is very small less than 10 whereas if 2V is 50 the isogyres move to the edge of the field of view If the isogyres move slowly out of the field of view when the stage is rotated the mineral is biaxial and the acute or obtuse bisectrix is near vertical The 2V is moderately large The optic sign cannot be deter mined if the bisectrix is close to vertical If the isogyres move quickly out of the field of view when the stage is rotated Figure OM2 then the optic sign can be determined but the distinction between uniaxial and biaxial is not clear cut 4 Crystal shape and cleavage Shape is not a diagnostic feature in thin section but is a useful guide Euhedral crystals of many minerals Optical Minerology have characteristic shapes and habits that can aid in the identification of minerals Cleavage is commonly observed as a set of cracks or bands in a mineral section Cleavage vertical to the section appears as fine cracks but cleavage oblique to the section will produce broad dark bands The num ber of cleavages an
312. ing and exercise caution when handling these sub stances Additional information on perchloric acid is available on pages EA2 1 and EA2 2 Apparatus 50 ml Teflon beakers plastic pipettes two 500 ml graduated plastic acid dispensing bottles with graduated dispensing reservoir to be used forthe T4A and T4B acid mixtures contain ing HF or HCIO two 500 ml low actinic glass acid dispensing bottles for dispensing concentrated HNO and HCl one 500 ml low actinic glass acid dispensing bottle with calibrated dispensing barrel for use with the Ru Re internal standard mixture Reagents Hydrofluoric acid HF 48 51 Hydrochloric acid HCl 36 38 Nitric acid HNO 69 71 Perchloric acid HCIO 62 70 Procedure 1 Reagent Preparation Two acid mixtures are used for sample preparation The composition of each must be recorded on the plastic dispensing bottles The dispensers are also labeled T4A and T4B 1 1 T4A solution is prepared by measuring con centrated 400 ml HF 40 ml and 40 ml HClO and mixing them in a 500 ml graduated plastic dispensing bottle When preparing these solutions always add the acid to water 12 4 solutionis prepared by measuring 380 ml deionized distilled water 70 ml and 30 ml HClO and mixing them in a 500 ml graduated plastic dispensing bottle 2 Standard Preparation 2 1 1 Pipette 5 ml of 1000 g ml Ru followed by 5 ml of 1000 g ml Re
313. ing is set at 200 300 mm Hg Adjustment is normally not required 3 Occasionally recovery of fluoride added to samples should be determined Low values indi cate a loss of fluoride possibly during pretreat ment high values indicate contamination EA23 4 4 The quality of alizarin fluorine blue is crucial to good performance It has been necessary to check several suppliers to find an acceptable grade of reagent Using good grade reagent an intense colored complex formed with fluoride can be developed The colour intensity or signal response can be monitored with a standard fluoride solution in order to determine whether the quality of the reagent is satisfactory 5 Refer to Technicon operation manual for trouble shooting should instrumental problems arise 6 Chloride and nitrate ions in percent concentrations can be distilled with fluoride ion and will interfere with the analysis by bleaching the alizarin fluorine blue lanthanum reagent Such high concentra tions of chloride and nitrate are not expected in rock samples 7 Thealizarin working reagent is stable at 4 C for at least 7 days 8 Samples with high fluoride concentration should be diluted to an appropriate level to fall within the optimum working range of 0 2 to 2 0 F ml with a solution containing 4g NaOH and 24 ml 1 1 HCIO per 100 ml 9 Byintroducing diluent into the reacting stream as indicated in Figure a linear calibration curve can be
314. ing the for mula observed check solution conc mean s d If the analytical error is normally distributed 95 of the results should be between 2 times s d When one or more analytes in the check solutions fall outside 3 times s d the operating parameters outlined in section 5 should be checked and restandarization of the system is necessary If reagent blanks are less than the method determina tion limits no further action is necessary However if one or more elements in the reagent blanks are greater than the instrument detection limits data will then be submitted to the Supervisor or ICP Spectroscopist for further decision Numerous in house MRB and international SRMs of varying geological compositions including GA BHVOI MRG 1 SY2 SY3 NIMD NIMP NIML NIMM NIMS GSS1 8 etc are used to monitor accuracy and precision within the ICP OES laboratory Productivity A technician should be able to complete 150 samples per day Additional Notes 1 The computer manufacturer recommends that the system boot be through the keyboard terminal EA18 20 rather than through the system switches General ly the system is left with the two drive doors open and all the switches at the ON UP positions To minimize the interelement spectral interferen ces a series of calibration standards is prepared from a serial dilution of stock standards There are six stock calibration standards prepared for the da
315. ing the required element s Send the furnace method s to the 188 CTF microprocessor by pressing ENTER Modify any fur nace parameters at this time Press the RECALL key to display the list of stored calibration curves NOTE If no curves are stored refer to notes under Autosampler with Dilutor Calibration with autosampler At this time return to Mode menu press 7 ENTER and select autosampler with diluter FIFTH Proceed with calibration if required or ana lyse samples See notes under Autosampler with Dilutor Calibration or Run Samples Further information can by obtained by referring to section 4 3 3 Calibration Procedure in the Video 22E operator s manual for creating curves NOTE Under furnace operation the RUN key on the 188 is used to initiate the analysis instead of READ EA3 7 Varian AA775 OPERATION OF THE ATOMIC ABSORPTION SPECTROMETER Varian AA775 Ensure that the proper instructions found in the operator s manual for the atomic absorption unit have been read The Varian AA775 is installed with a number of safety features which include Burner interlock preventing the lighting of the flame without the proper burner in place NOTE This system only works if the socket and cable attached to the burner is connected Automatic flame shut down with low fuel rates and when requested by operator Proper sequence for this procedure is performed Flame sensor to shut off fuel when flame is
316. into a pre dried porcelain crucible 1 2 Record the total weight of the sample and crucible with cover 1 3 Heat the sample in an oven at 105 110 C for at least one hour preferably overnight Par tially cover the crucible by tilting the lid to the side Moisture 1 4 Fully cover then remove the crucible and quickly place it in a desiccator Let cool to room temperature 1 5 Weigh the dried sample and the crucible with the lid as quickly as possible to avoid moisture being re absorbed by the sample 2 Calculation of the results The difference in weight before and after drying represents the amount of moisture or minus water in the sample w Percent of minus water x 100 where w original wt of the sample w wt oforiginal sample crucible with lid wt of dried sample crucible with lid Quality Control The determination limit for this method is 0 01 Accuracy and precision have not been established Productivity A technician should be able to complete 40 determina tions per day Bibliography Maxwell J A Rock and Mineral Analysis Inter science Publishers 1968 584 pages Potts P J A Handbook of Silicate Rock Analysis Blackie and Sons Limited Glasglow 1987 622 pages EA29 1 Insoluble Residue DETERMINATION OF ACID INSOLUBLE RESIDUE Introduction This method is used as a relative measure of impurities in carbonate samples In most samples silica
317. into a 500 ml volumetric flask Make to volume with 10 Use class A volumetric glassware 2 1 2 Transfer to a 500 ml glass dispensing bottle EA19 1 Traces ICP MS 2 1 3 Verify that the Ru and Re concentrations in the old and new standard solutions are the same Comparison is done by dispensing using the 500 ml internal standard dispensing bottle 1 ml of the standard into a 100 ml class A volumetric flask and making to volume with 10 HNO This solution is then be com pared against the old standard by examining the signal trace for each standard and each analyte on the ICP MS using the SPEC DIS program You should not be able to discern any differences between the signal traces for the two standard solutions 3 Sample Dissolution 3 1 1 Weigh 200 mg of sample into a Teflon beaker and add 15 mlof T4A solution Using the TAA solution wash down the sides of the beaker Prepare and carry at least 2 blanks and 2 ali quots of the digestion control material through the entire procedure see Quality Control Sec tion Place sample and acid on a hotplate which has been set to 120 C Leave overnight Con tamination of the sample can occur from debris falling from structural members of the fumehood above the hotplate so be sure that all necessary precautions have been taken to avoid this The next morning remove the beaker from the hotplate and gently tap the beaker to dislodge the cake Add 15 ml of the T4
318. ion Dis solve 5 g of mercuric thiocyanate in 1 liter of distilled water and allow to stand for 4 hours 2 Standard solution preparation 2 1 Stock standard solution 1000 ug Cl ml Dis solve 1 6485 g of sodium chloride which has been dried in an oven at 105 C for several hours in 1 liter of distilled water 22 Working standard solution Prepare 1 2 3 4 and 5 ug Cl ml standard solutions by serial dilution of the stock standard solution with 656 nitric acid 3 Fusion and decomposition of sample 3 1 Weigh out 0 150 g of powdered rock sample and 0 300 g of anhydrous lithium metaborate into a graphite crucible Mix thoroughly 3 2 Fuse the sample at 860 C in a muffle furnace for 15 minutes 3 3 Quickly transfer the molten sample into a 50 ml teflon beaker containing 10 ml of 9 nitric acid Stir the solution using a magnetic stirrer for at least 1 hour to dissolve the fusion cake 3 4 Transfer the contents to a test tube calibrated at 15 ml and make to volume with distilled water Seal the test tube with a piece of Parafilm and mix the solution thoroughly EA24 2 3 5 Prepare a reagent blank simultaneously Decant a portion ofthe solution to a sample cup for chloride determination as described below 4 Measurement of Cl concentration 4 1 the power on all modules except the sampler 4 2 Place the reagent feedlines into the proper con tainers see manifold in Figure 4 3
319. ision at 9546 confidence limit 20 at 10X deter mination limit 100 ppm is 20 ppm absolute Traces AA Copper Cu STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 3 5 Wavelength nm 324 8 Spectral Band Pass nm 0 5 Background Correction OFF Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Cu solution reads 0 200 absorbance Calibration Set 1 00 ppm to read 1 00 Working range 0 5 to 4 0 ppm INTERFERENCES Few interferences with air acetylene flame One percent Fe in solution i e 50 Fe in the sample can cause a 10 suppression High Zn Cu ratios can cause some suppression of the Cu signal Use a leaner air acetylene flame to mini mize this effect ANALYTICAL CAPABILITIES Determination Limit ppm 5 Precision at the 95 confidence limit 26 at 10X determination limit 50 ppm is 4 ppm absolute EA17 5 Traces AA Nickel Ni STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 232 0 Spectral Band Pass nm 0 2 Background Correction ON Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Ni
320. istillation 2HF 165 C Na S Safety advisory 1 This method makes use of various acids Make sure that all pertinent MSDS sheets are reviewed before starting 2 In preparation of the 1 1 H5SO slowly add sulphuric acid in portions to 500 ml of distilled water and mix well Cool the solution in a water trough and ensure that the temperature of the solution is kept below its boiling point during preparation 3 Preparation of the acetate buffer solution and the alizarin fluorine blue stock solution should be carried out in a fume hood to avoid inhalation of vapors of glacial acetic acid and ammonium hydroxide Method This method consists of the following techniques 1 Fusion and sample decomposition 2 Distillation for separation of analyte 3 Colorimetric measurement 4 Calculation of F concentration based on calibra tion curve produced from known standard solu tions Apparatus Nickel crucibles 40 ml Hot plate Plastic beakers 50 ml graduated Lachat colorimeter with flow cell and 620 nm interference filter Recorder Linear Model 1200 Technicon Auto Analyzer for fluoride analysis consisting of the following components A Sampler IV with 5 ml plastic sample cups B Proportioning Pump III with pump tubes required for fluoride analysis A flow diagram of the analytical system is shown in Figure F1 C Microdistillation Apparatus shown sche matically in Figure F2 The major c
321. ite for permission to the Director Ontario Geological Survey Ministry of Northern Development and Mines 11th Floor 77 Grenville Street Toronto Ontario M7A 1W4 Parts of this publication m y be quoted if credit is given It is recommended that refer ence be made in the following form Ontario Geological Survey 1990 The analysis of geological materials volume II a manual of methods Ontario Geological Survey Miscellaneous Paper 149 Commerce 250 90 TABLE OF CONTENTS MINERAL SCIENCE SECTION Method Technique The Technique of Sample Preparation Assay Sample Preparation Whole rock Sample Preparation Carbonate and Trace Element Preparation for Soils Conodont Separation and Preparation Grain Size Analysis Introduction Conventional ASTM D422 72 Grain Size Analysis Grain Size Analysis by Particle Sizing Atterberg Limits ASTM 0423 66 Separation of Minerals Using Heavy Liquids Mineral Separation sing the Frantz Magnetic Separator Rock and Mineral Identification for Prospectors and Geologists Optical Mineralogy X ray Powder Diffraction X ray Diffraction Identification Determination of Specific Gravity Determination of Moisture Content of Soils ASTM D2216 71 Fire Assay Introduction Conventional Fire Assay Method for Au and Ag Fire Assay Preconcentration for Determination of Au Pt Pd by GFAAS Nickel Sulphide Fire Assay Normative Programs Alknorm for Feldspathoidal and Melilitic Igneous Rocks
322. ith a bowl of ethylene glycol in the bottom and leave in an oven at 60 C for at least 4 hours The sample must be run immediately on removal from the desiccator 4 3 The sample on the porcelain tile should be heated to 400 C for at least a half hour and then run on the XRD 44 This sample is then reheated to 550 C for at least a half hour and re run The heated samples should be run immediately on removal from the furnace 4 5 Interpretation of the patterns may carried out using the indexing procedure described above MS11 2 or a flow sheet for clay mineral identification as in Starkey et al 1984 Quality Control The above technique is a qualitative means of iden tification although abundances can be estimated using the relative intensities of each phase present The absorption effect is variable for each mineral present so these relative intensities can be misleading par ticularily if iron minerals are present A quartz sample should be run regularly to check that the pattern obtained is the same as the standard JCPDS one If not there may be an alignment problem The detection limits of minor phases depends entirely on their chemistry and on whether the mineral is likely to have a preferred orientation which may enhance one of its lines A detection limit of 1 is assumed by most workers Klug and Alexander 1971 Productivity Eight to ten samples can be run and indexed in a day Bibliography Jenkin
323. ith half this amount of If there is still an excess of Fe it is calculated as Hematite Wollastonite is formed from the amount of Ca left and an equal amount of Si Enstatite and ferrosilite are formed provisionally from all the Mg and If there is an excess of Si it is calculated as Quartz If step 13 is true the norm calculation is finished otherwise Si has been assigned beyond the original amount and is a negative quantity The following steps bring Si back to 0 by the minerals of alower degree of silification substituting in part or wholly for those minerals that were formed provisionally The amount of Mg and Fe used to form Enstatite and Ferrosilite are added and the relative amounts of Mg and Fe calculated using the ratios noted here F e Mg Fe Mg Mg Fe If the amount of Ca in Wollastonite is greater than the total Mg Fe all the Mg and Fe will be converted with Ca to Diopside and Hedenbergite respectively Diopside MgCa SiO is equal to 4 times the amount of Mg 16 17 Hedenbergite FeCa SiO3 is equal to 4 times the amount of Fe Wollastonite is now equal to its original value minus 2 Mg Fe Enstatite and ferrosilite now equal 0 If the amount of Ca in Wollastonite is less than the total Mg Fe all of the Wollastonite will be con verted to Diopside and Hedenbergite with the right proportions of Mg and Fe T cis Ca Mg x4 Diopside M
324. ity of silicosis THIS LABORATORY AREA IS MONITORED UNDER A SILICA CONTROL PROGRAM 2 Wear a face shield or safety goggles 3 Wear ear muffs Sound levels from the jaw crushers can exceed 100 dB 4 Wear a laboratory coat at all times in the area and take it off before leaving 5 Do not eat smoke or drink in the grinding area 6 Be aware of samples requiring special handling These samples will be flagged e g As Pb contain ing If you identify a potential hazard then it is your responsibility to flag the samples 7 Ensure that the main exhaust system is switched on during grinding operations 8 Observe safety procedures specific to each piece of equipment Ensure that the lids on the jaw crushers are closed immediately after the sample is introduced The mills on the vibratory ring pul verizer also called a Swing Miller should be firmly secured before the equipment is switched on 9 Uncontrolled cleaning of equipment and clothes using compressed air is not acceptable Technique Assay sample preparation involves the following pro cedures 1 Sorting of samples in preparation for grinding 1 2 2 Crushing the samples sequentially using a jaw crusher 3 Riffling to split the samples retaining one split for grinding and another split as a back up 4 Grinding the split in the mill on the vibratory ring pulverizer for the appropriate length of time 5 Removing pulp after grinding onto glazed
325. ium phosphate and sul phate will depress the magnesium signal in the air acetylene flame Strontium addition and matrix matching of samples and standards will correct for these interferences and any ionization of magnesium in the flame Ionization of magnesium in the nitrous oxide acetylene flame is controlled with the added strontium to the solutions NOTES 1 Nitrous oxide acetylene flame is preferred al though the air acetylene flame could be used in the same manner as with the determination of calcium t3 The signal noise with the nitrous oxide acetylene flame is not as severe as that observed when deter mining calcium with this flame 3 The fluorborate solutions tend to diminish the chemical interferences in the flame attributed to the formation of inter oxide compounds such as magnesium aluminate calcium silicate etc A fluorborate solution binds interfering elements to fluorine whereas sulphate and phosphate inter ferences would probably not be eliminated Iron Oxide Total Iron Fe O STANDARD SOLUTIONS Use certified reference materials prepared in the same manner as the samples INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 248 3 Spectral Band Pass nm 0 2 Flame Description Air acetylene Oxidizing fuel rich blue INTERFERENCES Matrix matching of samples and standards is recom mended Majors AA EA7 7 Majors Classical DETERMINATION OF MAJOR ELEMENTS SiO2
326. ive furnace infra red method refer to EA12 1 Non carbonate carbon cannot be determined directly however by determining carbonate carbon non car bonate carbon can be calculated by subtracting car bonate carbon from total carbon The determination of carbonate carbon on the Coulometrics Determinator is initiated by heating a known weight 0 05 0 50 g depending on the carbonate content of sample with 2 ml of 2N perchloric acid in the heated reaction tube The evolved CO is swept by a stream of filtered air into the Coulometrics cell which is filled with a partially aqueous medium containing ethanolamine and a colorimetric indicator When CO is passed through the cell solution it is quantitatively absorbed and converted to a strong titratable acid by the ethanolamine causing the colour of the indicator to fade As soon as this happens the coulometer electrically generates base to restore the colour The accumulated charge coulombs is displayed on a digital readout as micrograms of carbon When the accumulation ceases the end point is reached The percent of carbon in a sample is then mathematically converted to percent of Safety advisory 1 Due to the odor of ethanolamine coming from the coulometer cell the analytical operation should be performed in a well ventilated area or in a fume hood Method The method consists of the following techniques 1 Decomposition of the sample 2 Measurement of CO
327. ively to a clean 250 ml beaker EA11 2 2 522 2 3 2 4 2 5 Weigh exactly 1 9069 g dried at 105 C and transfer quantitatively to the 250 ml beaker containing the NaCl Dissolve in about 150 ml distilled water Transfer to a 1 liter volumetric flask quantita tively by washing the 250 ml beaker several times with small portions of distilled water Make to volume 1 liter with distilled water Mix well and store in a polyethylene bottle 3 Sample decomposition 3 1 3 2 39 3 4 3 5 3 6 3 7 3 8 3 9 3 11 Weigh exactly 0 125 g of sample and transfer to a 50 ml platinum dish Moisten with about 1 ml of distilled water Coverthe dish with a watch glass if carbonate is present and add 5 ml of conc When effervescence has ceased remove and rinse off the cover in the dish with distilled water Evaporate to complete dryness on a hot plate Cool add 10 ml of conc 5 ml of HF 48 using plastic graduated cylinder and 2 ml of 1 1 H SO using a pipette Allow to go into solution at a moderate heat and take down to a low volume approximate ly 10 ml Add another 5 ml of conc and 5 ml of HF 48 Evaporate to complete dryness until no more fumes of SO are visible In order to remove the last traces of SO3 hold platinum dish using platinum tipped tongs and heat very carefully with a Meker burner until the reappearance of SO fumes and f
328. k solution 1500 meq to each of the 500 volumetric flasks 4 1 3 Make to volume 500 ml with distilled water Mix well transfer to the polyethylene bottles and store 4 1 4 This will give a concentration of 0 2 5 5 10 15 and 20 ppm Na and K in the solution Calibration solutions are stable 4 2 Preparation of Li blank diluent 4 2 1 Add 5 ml using a 10 ml microburette of Li stock solution 1500 meq 1 into a 500 ml volumetric flask and make to volume with distilled water 4 2 2 4 2 3 Sodium Potassium Mix well and store in a polyethylene bottle This is the lithium blank diluent which is used to centre lithium standard meter and also to set Na and K zero on the instrument 5 Measurement of Na and K concentrations 5 1 5 1 1 5 12 9 23 5 2 1 5 2 2 Starting up Set the Display switch to Continuous Check the drain line is filled with water If in doubt inject a few milliliters of distilled water into the drain tube outlet and allow the excess to drain off Open the valve at the top of the propane cylinder one full tum only If a central air supply is being used open the air valve If the air filter is fitted with a manual drain ensure this is closed Remove distilled water cup from the sample tray Switch on power Check gas air and flame indicator lamps are lit in sequence If any of the above fail to occur gas and air supplies will be automat icall
329. ker Allow the contents to cool Add 10 ml of concentrated to the beaker Transfer the solution to a 50 ml graduated cylinder and make to volume with distilled water Stopper the cylinder and mix the solu tion thoroughly Prepare a reagent blank simultaneously For Sb analysis Weigh out 0 100 g of rock sample and transfer to a 30 ml teflon beaker Digest the sample with 5 ml of acid digestion mixture 1 on a hot plate at low heat for ap proximately one hour until white fumes of sulphuric acid appear and the volume is reduced to 1 2 ml Avoid heating the contents to dryness Cool and dilute the contents with 10 ml of 1 4 3 2 3 3 2 4 Heatthe contents to near boiling and cool again to room temperature 3 2 5 Reheat if any white precipitate is present 3 2 6 Transfer the contents with rinsings to a borosilicate test tube graduated at 15 ml Make to volume with 1 4 Seal the test tube with a piece of Parafilm and mix the solution thoroughly 3 2 7 Prepare a reagent blank simultaneously 3 3 1 For Bi analysis Weigh out 0 100 g of rock sample and transfer to a 30 ml teflon beaker 3 3 2 Digest the sample with 5 ml of the acid diges tion mixture 2 on a hot plate at low heat for approximately one hour until white fumes of perchloric acid appear and the volume is reduced to 1 2 ml 3 3 3 Avoid heating the contents to dryness Cool and dilute the contents with about 5ml of 1 4
330. kes the surface Allow the precipitate to settle and confirm that the end point has been reached the solution should smell faintly of ammonia Boil for one minute let precipitate settle and filter through a well fitted 12 5 cm Whatman No 40 filter paper in a 75 mm filter funnel NOTE An excess of ammonia is avoided to prevent the redissolving of Al OH 3 An excess has effect on Fe OH 4 1 9 Catch the first few milliliters of filtrate in a 150 ml beaker If the filtrate is cloudy re filter catching the solution in the original beaker Repeat these steps until a clear filtrate is ob tained NOTE In this ammonia precipitation Fe Al and Ti present are precipitated as hydroxides Any small amount of phosphate present is also precipitated as Fe or Al phosphate 4 1 10 When the filtrate is clear replace the small beaker with one of 600 ml capacity and filter the remainder of the solution as readily as possible keeping the bulk of the precipitate in the beaker NOTE The filtrate from this precipitate contains am monia and sodium salts as well as Ca Mg and most of the Mn orginally present 4 1 11 Transfer the precipitate to the paper wash the beaker and stirring rod twice with hot 296 NH4NO neutralized solution Wash the paper and precipitate ten times taking care to wash the precipitae away from the edges of the paper EA8 5 Majors Classical 4 1 12 Wipe the lip of the beak
331. lass bottle Boric Acid H4BO 4 5 stock solution Dissolve 45 g in distilled water by heating slowly When dissolved cool and make to 1 liter with distilled water Store in a polyethylene bottle 2 Standard solution preparation 1 00 mg 2 1 22 2 3 2 5 2 6 Weigh exactly 0 959 g of potassium phos phate monobasic KH PO dried at 100 C Transfer to a 100 ml glass beaker Dissolve in distilled water Potassium phospate monobasic should be soluble without heating Transfer to 500 ml volumetric flask quantita tively washing beaker with several small por tions of distilled water Make to volume with distilled water Store in a tightly capped polyethylene bottle It is always a good practice to store standard solutions in a tightly capped bottle to minimize evaporation of the solution 3 Sample decomposition 3 1 Weigh exactly 1 000 g of sample and transfer to a 50 mi teflon dish NOTE Since the presence of in rock samples is EA10 2 usually in the range of 0 1 0 5 a 1 000 g sample can be used If P O is in a greater concentration less sample may have to be used 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 3 12 3 13 3 14 3 15 3 16 Moisten with distilled water Cover the dish and add 10 ml of concentrated When effervescence has ceased remove and rinse off the cover Add 10 ml of 48 HF Place the dish on
332. late for 1 minute 6 14 Remove the beaker and add a few drops of allow the reaction to subside and add 15 ml of distilled water 6 15 Heat on the hotplate for 15 minutes or until dissolution is complete 6 16 Transfer the cooled solution to a 50 ml polypropylene centrifuge tube and bring to the 25 ml mark with distilled water 6 17 Cover the test tube with parafilm or a cap and mix well 6 18 Add a portion of the solution to a 17 x 100 polypropylene culture tube and issue to ICP OES for measurement of analyte concentra tions see Note 5 NOTES 1 The sample weight and beaker size depends on the density of the vegetation material Usually 20 g of sample and 100 ml beakers are used however 10 g or 250 ml beakers are alternate choices 2 New beakers need to be conditioned at least three times before they are used for ashing Condition ing involves heating the beakers in a muffle fur nace at 550 C for three hours and removing the beakers from the furnace to cool Conditioned beakers are cleaned by adding 1 1 nitric acid to the beakers covered with a watch glass and allowing the acid to reflux by heating on a hotplate They are then thoroughly rinsed with distilled water and dried at 105 110 C 3 The charred material in the beaker may be stirred and left overnight to thoroughly ash the sample 4 The steps which follow are essentially the same as those used for the T1 options and T2 analytical package pro
333. le etc this contribution can be subtracted from the observed raw count rate before other corrections are made to it This is done in the RC Rate Correction Table under the column BKGR The RC table is also used to control contributions to peak count from other channels analytes or background The contribution from the various channels should be identified independently before filling in the RC table The coefficients used in the correction are entered in the table as L factors Up to four such corrections can be applied to a single channel Examples are shown below EA6 22 Majors XRF Example 1 Peak Background Both channel offsets and independently defined channels can be used to define a peak background or part of the counts at the background position can be subtracted from the peak counts to give a net P B count rate This is useful for samples where differences in the background can contribute strongly to the peak count rate If the background is not totally flat a background correction factor can be applied For example to determine background contributions for a given combination of trace elements using a single background position a quartz pellet is run as a blank and raw intensities printed out Background correction factors defined as CPS analyte CPS background are calculated and entered as the L values in the RC table Example 2 Interference Correction The regression package of the P
334. le for ac curate work Therefore should be determined by Flame Atomic Absorption as described in the method Major Elements by Flame Atomic Absorption Spectrometry page EA7 1 of this manual 5 1 Determination of CaO 5 1 1 The calcium is determined in the filtrate from the RO precipitate 5 1 2 Heat the solution in 600 ml beaker and evaporate to about 200 ml Make it acidic with 12 M HCI Add a few drops of methyl orange 0 02 aqueous solution indicator Dissolve 3g ammonium oxalate NH4 C 0 H O in 50 ml of distilled water heat to 70 80 C and filter through a 12 5 cm Whatman No 40 paper into the sample solution if several precipitations are to be done use 50 mi aliquots of hot filtered 6 solution of am monium oxalate NOTE The amount of ammonium oxalate to take depends on the amount of Ca to be expected from the nature of the rock e g 3 g am monium oxalate is enough up to 50 CaO based on a 0 8 g sample weight NOTE The ammonium oxalate solution is filtered to remove small amounts of impurities Calcium oxalate is often present Majors Classical 52 Calcium first precipitation 5 2 1 Heat the solution to near the boiling point and add aqueous ammonia 1 1 dropwise while stirring vigorously until the indicator changes colour and then add about 1 to 2 ml in excess 5 2 2 Heatto near boiling but do not boil and allow to stand without further heating 2 3 hours with occasional s
335. lements such as Ni Sc Y Nb REE Ce La Nd Sr and V usually occur at trace levels in rocks and are used as discriminators to determine origin tectonic setting or degree of alteration Other elements such as W Co Be Cu and Zn are used more specifi cally to assess rocks for ore potential An inductively coupled plasma source emission spectrometer JY48 is used to perform elemental analysis on samples which have been decomposed using a wet chemical acid digestion procedure The TRACE 2 T2 package elements their deter mination limits optimum range and precision are listed in Table OES1 Safety Advisory UNTRAINED OPERATORS SHOULD NOT AT TEMPT TO START OR USE THE EQUIPMENT WITHOUT PRIOR TRAINING There are five types of hazard associated with this apparatus electrical radiation high temperature noxious gases and physical hazard 1 Electrical hazards can be encountered in three areas the plasma power generator the plasma torch compartment the spectrometer tank com partment and associated with various peripheral equipment like pumps autosamplers and other special apparatus which may be set up to facilitate the analysis The power generator is of particular concern because high voltages are retained on capacitors even when the power has been com EA18 14 TABLE OESI Element Determination Optimum Precision Limit Range ppm ppm Be 1 1 100 1 Co 5 5 1000 10 Cu 5 5 1000 10 Mo 10 10 4000 30 Ni 5 5
336. lene flame con tribute to the noise of the absorbance signal A strip recorder is used to record the signal The noise may also be reduced by increasing the lamp current and thereby decreasing the PM voltage 2 Runcalibration standards frequently to ensure no loss in sensitivity If this occurs check fuel flow burner clogging or loss of peak alignment EA17 7 Traces AA 3 Dilute samples outside of largest calibration range BEFORE adding buffer solution ANALYTICAL CAPABILITIES Determination Limit ppm 10 Precision at the 95 confidence limit 20 at 10X determination limit 100 ppm is 16 ppm absolute EA17 8 Lithium Li STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm stock Lisolution to prepare 0 5 1 0 2 0and 4 0 ppm working standards Add 20 ml of 10 000 ppm for every 100 ml of working standard prepared 1 ml 2000 ppm INSTRUMENT PARAMETERS Flame Emission Single Beam Wavelength nm 670 8 Spectral Band Pass nm 0 2 Background Correction OFF Flame Description Nitrous oxide acetylene Fuel lean small red cone WORKING CONDITIONS While aspirating a 2 ppm Li solution set absorbance to read approximately 0 750 Calibration Set 1 00 ppm to read 1 00 Working range 0 5 to 4 0 ppm INTERFERENCES Ionization in a nitrous oxide acetylene flame is over come with the addition of 2000 ppm NOTES 1 Most rock samples have sufficient concentration ofeasily ioni
337. lizing air for several seconds to clean out the capillary to the FASTAC Once standards have been prepared and analyzed the CRT displays the calibration curve for channel A Follow the prompts shown When channel A has been accepted the calibration curve for channel B will be displayed Run Samples ENTER Change to read 0 0 mls matrix modifier To use the manual dispense mode enter a value of zero for the Sample Uptake Volume When prompted for Dispensed Volume enter the volume to be placed into each sample test tube In the manual dispense mode 75 samples can be analyzed With matrix modification 37 empty test tubes are required there fore 37 samples can be analyzed CRT displays options for program to run samples CRT displays option for Initial AZ amp AC NO is normally selected following calibration YES is nor mally selected following the recall of a stored calibra tion curve CRT displays Auto Deposit Adjust if FASTAC and concentration mode is being used If selected the system will automatically cut the deposition time in half for any sample which gives a CONC HIGH read ing NOTE Make sure initial deposition time is an even number so the ADA division will not intro duce inaccuracies due to arithmetic rounding For example 6 5 sec would be cut to 3 2 seconds CRT continues to display options similiar to those in CALIBRATION above Recall Menu The Recall menu is used to examine calibration c
338. lphide fire assay Method 3 is detailed later in this section Apparatus Two regular fire assay furnaces used to prepare beads One is used for ore grade material and the other for low abundance samples Onecupellation furnace for the preparation ofthe prill Pouring plates crucibles cupels Balances capable of weighing to 0 01 mg Parting dishes and acid dispenser Fume hood MS14 1 1990 y71 Reagents The stock flux contains the following TABLE FAI Component Weight g litharge 66 55 sodium carbonate 33 6 28 silica 9 7 5 borax glass 8 4 7 flour 3 2 5 Nickel sulphide buttons require the use of nickel carbonyl sulphur Silica gel Sodium carbonate sodium metaborate Method 1 Conventional Fire Assay Method Procedures 1 1 Weigh out rock pulp 14 583 g 1 2 assay ton into a 20 g crucible 1 2 Add pre mixed stock flux approximately 120 g 1 3 Mix rock pulp and flux in crucible 1 4 The position of each sample in the furnace is noted it is not possible to write on the crucible unless a GRAPHITE pencil is used 1 5 Place in assay furnace preheated to 1025 C and heat for 35 minutes 1 6 Pour molten charge into cast iron mold 1 7 Inspect crucible for lead loss Figure FA1 1 8 Note slag colour for possible interferences 1 9 Note size and appearance of lead button 1 10 Break slag and free the 20 25 g lead button 1 11 Hammer the lead button i
339. ls collected to 0 001 2 Remove all magnetic minerals from the sieve Weigh the non magnetic fraction to 0 001 g 4 Calculations PH where PH WH W PM where PM WN Productivity 100 WH x Ww percentage of heavy minerals in the sample weight of heavy minerals in grams and weight of material used in grams 100 WH WN x W percentage of magnetics in the sample and weight of non magnetics A technician should be able to complete 25 samples over a period of 2 days Magnetic Separation MINERAL SEPARATION USING THE FRANTZ MAGNETIC SEPARATOR Introduction Many different minerals may be separated from each other on the basis of their magnetic susceptibility For practical purposes minerals can classed into three groups depending on their magnetic properties l Ferromagnetic the most magnetic minerals eg magnetite These are actually strongly paramag netic minerals 2 Paramagnetic most minerals are paramagnetic and are attracted by a magnetic field 3 Diamagnetic weakly magnetic minerals repelled by the magnetic field eg quartz feldspar The Frantz magnetic barrier separator consists of a vibrating inclined chute partly divided along its length along which minerals are fed specially designed pole pieces exert a strong magnetic barrier field along the centre of this chute Mineral separation takes place in the middle of the chute by balancing magnetic forces on each mineral
340. lt 40 Wt then 13 g of silica is added STAGE 4 For each sample 60 g of Na BO and 30 g of Na CO is added to the charge 3 1 3 A standard reference material SARM 7 together with one of the MRB PGE standards MRB19 22 is included with each batch of samples The SARM 7 standard may be prepared by mixing 9 g S with 15 g Ni and adding 35 g of pulp 60 g Na BO and 30g are also included but no silica is added A 30 g assay crucible is used for the charge and the components are thoroughly mixed The position of the charge in the furnace is noted for each sample to avoid confusing the samples it is not possible to write on the crucible unless a GRAPHITE pencil is used The charge is fused for 90 minutes at 1000 C in the Globar fumace When the reaction is complete the charge is removed from the furnace and cooled The nickel sulphide button is removed from the crucible with a hammer and weighed The nickel sulphide bead is broken with the Rocklabs little smasher a hand held steel pulverizer and the fragments are milled in zirconia or alumina mills to produce a fine powder of 70 mesh 3 1 8 The sample is weighed to determine the loss during grinding and samples are passed on to the Chemistry subsection for the concentra tion of the PGE before determination by INAA 32 Concentration of the PGE The procedure for the concentration of the PGE from a crushed nickel sulphide button is outlined below
341. lysis The RF power generator is of particular concern because high voltages are retained on capacitors even when the power has been completely disconnected from the instrument DO NOT ATTEMPT TO GAIN ENTRY TO THE RF POWER GENERATOR WITHOUT PROPER TRAINING Other areas are protected by interlocks DO NOT OVERRIDE INTERLOCKS EA19 13 Traces ICP MS 2 High voltages should be marked stating the ap proximate voltage Wear safety glasses where sparks or arcing may occur Remove rings and metal watchbands when working with circuits or control devices Never handle electrical equip ment with wet or perspiring hands Some high voltage danger points are Transformer terminals Rectifier tube plate caps Filter capacitor terminals Filter choke RF tuning capacitors and coils Fuse panels 3 Twotypes ofelectromagnetic radiation are of con cern radio frequency and ultraviolet Radio fre quency radiation has no known teratogenic effect but can cause somatic damage Such radiation could affect eyesight as the eye fluids will absorb the radiation which causes a damaging increase in pressure within the eye Ensure that the plasma torch compartment is well shielded by inspecting the viewing and access ports to make sure that the RF radiation cannot escape The 50 ohm coaxial cable should be inspected to ensure that it is a tight fit and that no corrosion has occurred at the con necting points on both the instrument and on the
342. maintained even at low concentrations of F Bibliography Operation Manual for the Technicon AutoAnalyzer II Technical Publications No TAO 0159 10 No TA1 0257 10 No TA0 0219 20 and No TD2 0170 00 1972 Fluoride in Plant Tissues Industrial Method No 206 72A Revised August 1978 Technicon Industrial System Tarrytown N Y Chan C 1983 Semiautomated Determination of Fluoride in Rocks American Laboratory Vol 15 No 10 pp 32 41 Cralley L V and Weinstein L H 1969 Tentative Method of Analysis for Fluoride content of the Atmos phere and Plant Tissues Semiautomated Method Health Laboratory Science Vol 6 No 2 pp 84 101 Fuge R 1981 Determination of Fluorine and Chlorine in eight USGS Reference Samples Using Automated Photometric Analysis Geostandards Newsletter Vol V No 2 Kesler S E and Van Loon J C 1973 Analysis of Fluoride in Rocks and an Application to Exploration Journal of Geochemical Exploration Vol 2 pp 11 17 Flouride EA23 5 amp SD tee AIR Heating Bath with Distillation Coll Waste Vacuum Pup 1007 COLORIMETER 620 nm Waste Waste To Sampler IV Pu EUR 3 90 amp Wash Receptacle PUR WHT ORN ORN PUR PUR BLU BLU ORN ORN BLK BLK GRY GRY ORN OR 3 90 2 50 1 60 0 42 0 32 1 00 0 42 GRN GRN 2 00 SAMPLE 2304 1 1 RESAMELE SAMPLER IV DIWENT AIR A
343. make up to 200 ml with distilled water and mix well Store in a glass bottle Titanium 2 Standard TiO solution preparation 0 5 mg TiO ml 2 1 22 2 3 2 4 2 6 2 7 2 8 2 9 Weigh exactly 2 2163 g of potassium titanium oxalate K TiO C O 2H 0 and transfer quan titatively to a 500 ml Erlenmeyer flask Add 8 g of diammonium sulphate NH4 SO Add 100 ml of concentrated H5SO Place a short stemmed glass funnel in the neck of the flask Gradually heat to boiling and boil for 5 10 minutes very carefully Continue the heating until complete solution has been effected and no unattacked material remains on the walls of the flask Cool and transfer to a 1000 ml volumetric flask already containing 500 ml of distilled water Wash the Erlenmeyer flask with several por tions of 5 HSO and finally with distilled water and transfer all washings into the 1000 ml volumetric flask When cool make to 1000 ml with distilled water 3 Sample Decomposition 3 1 3 2 3 3 3 4 Sm 3 6 3 7 3 8 Weigh exactly 0 500 to 1 000 g depending on the amount of TiO present of sample and transfer to a 50 ml platinum dish Moisten with about 1 ml of distilled water Cover the dish and add 10 ml of concentrated Heat a hot plate for about 30 minutes When effervescence has ceased remove and rinse the cover with distilled water adding washings to the dish Add 10 ml
344. me type but dif ferent names the wild card can be used to represent the name For example COPY SY TYP DY1 5 All files with the exception of systems files type SYS can be copied with the use of a double wild card e g COPY SY DY1 6 The instructions given above assume that the name and type of the file will not be changed in the copy Files can be renamed in the copy command by the following instruction COPY SY XXXXXX TYP DYL YYYYYY TYP A copy of a file can be made on the same disk in this fashion e g COPY DY1 XXXXXX TYP DY1L YYYYYY TYP 7 The instruction given in 5 above results in the indiscrimate copying of all files In order to exer cise some control over the files to be transferred a special command can be appended to the copy instruction i e COPY SY DY1 Q The name of each file to be copied appears at the terminal and the copy instruction accepted or ig nored on the basis of the Y or N response a carriage return is equivalent to N 8 To copy systems files SYS the instruction is COPY SYS SY SYS DY1 or COPY SYS SY SYS DY 1 Q To copy all files including the systems files as in the case of duplicating a systems disk the instruc tion will be COPY SYS SY DY1 or COPY SYS SY DY1 Q 9 In the case of duplicating a systems disk it is important to copy over the BOOT routine The following command sequence is used COPY BOOT SY
345. med by the three strongest absorption lines of Mn may not be resolved with all monochromators 3 soils and sediments require a 1 10 dilution to be made on the solution prepared by acid diges tion Traces ANALYTICAL CAPABILITIES Determination Limit ppm 5 Precision at the 95 confidence limit 20 at 10X determination limit 50 ppm is 10 ppm absolute EA17 9 Traces AA Iron Fe STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 248 3 Spectral Band Pass nm 0 2 Background Correction OFF Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Fe solution reads 0 145 absorbance Calibration Set 1 00 ppm to read 0 50 Working range 0 5 to 4 0 ppm INTERFERENCES A reduction in sensitivity has been observed when iron is determined in the presence of nitric acid and nickel This effect is minimized by using a very lean flame All interferences can be removed with the use of a nitrous oxide acetylene flame NOTES 1 To reduce signal noise the gain is reduced by setting working standards to one half values during calibration To obtain the correct con centration value for the samples the readout must be multiplied by 2 before reporting the result 2 Most soils and sediments require a
346. mermann Reinhardt reagent Dissolve 140 g of MnSO 4H 0 in 1 liter of distilled water in a 2 liter glass beaker Cautiously add 250 ml of concentrated H5SO Add 250 ml of 85 phosphoric acid H4PO Dilute to 2 liter with distilled water Potassium permanganate KMnO 0 1N solu Weigh 32 0 g of potassium perman ganate crystals and transfer to approximately 2 liters of distilled water in a 2 liter glass beaker Heat to boiling and keep hot for one hour Cover and let stand overnight Filter the solution through glass wool into a 10 litre dark brown glass bottle Add 8 liters of distilled water Mix the solution thoroughly and let stand overnight before standardization 2 Standardization of KMnO Standardize in triplicate against a National Institute of Stand ards and Technology NIST Reference Material e g NIST 29 a Fe 69 54 or NIST 27 e Fe 66 6 2 1 Sample decomposition EA14 2 Weigh 0 200 g of 29 a for example and transfer to a 50 ml teflon dish Add 10 ml of HCl and 10 ml of distilled water Heat for a few minutes make sure most of the sample is in solution Add 5 ml of HF Evaporate to dryness 2 1 6 Add5mlofconcentrated and leave it for 1 or 2 minutes Then add about 25 ml of distilled water 2 1 7 Heat well and make sure that the sample is completely dissolved 2 1 8 If any black gritty particles are noticed the solution should be filtered using a Whatma
347. methods and the Hiac Ryco particle sizing system It is best applied to the determination of particle sizes for samples which are sandy or where specific informa tion is required about particle sizes between 2 and 700 microns Automated grain size analysis is not suited for routine application as a substitute for ASTM tech niques for clay rich samples Method The method consists of the following techniques 1 Sample preparation samples are dried and clumps of particles are broken down using a soil breaker 2 Separation of soil particles the sample is sieved to 10 mesh and wet sieved in the presence of a deflocculant See previous ASTM 0422 72 method using a 14 18 25 and 230 sieve 3 Calculation of results a program is used to com pile the data into an ASCII MS DOS file which is then reported to the geologist Apparatus Sieves Soil breaker Mortar and rubber pestle Grain size analysis system Hydrometer cylinders and hydrometer Thermometer Reagents Sodium hexametaphosphate See previous ASTM D422 72 method for preparation instruc tions Page MS4 3 Procedure 1 Preparation of sample The distribution of particle sizes coarser than 710 microns retained on No 25 sieve is determined by wet sieving The distribution of particles coarser than 62 microns but finer than 710 microns is deter mined using a particle size analysis system equipped with dry sensor The particle size distrib
348. mold or into a mineral acid solution The tetraborate salt is utilized to prepare glass buttons in a platinum mold for presentation to an XRF spectrophotometer The metaborate flux can be sub stituted for tetraborate offers a lower fusion tempera ture 849 C versus 917 C and provides a more fluid melt for pouring and consequently less retention of material in the crucible EA2 8 Graphite crucibles are normally used when the melt is to be poured quantitatively into a mineral acid solution typically 4 HNO for presentation to solution based instrumentation The tetraborate salt with a relatively higher acidity than the metaborate salt is more suitable for fusions of basic rocks and minerals e g dolomite For acidic rocks high silica the metaborate salt is preferable Flux to sample ratios are usually 5 1 l l Fusion for determination of Barium and Chromium This fusion is suitable for barium concentrations of 0 05 40 0 percent and chromium concentrations of 100 ppm to 5 0 percent when determined by AAS This procedure may also be used on any residue following an acid digestion the weight of flux being dependent on the amount of residue present 1 1 1 Weigh 0 200 g of sample into a porcelain crucible see Note 1 1 1 2 Add 1 0 g of lithium metaborate and mix sample and flux with a small teflon coated spatula see Note 2 Transfer quantitatively to a graphite crucible and place on a silica tray see Note 3 F
349. mpler and skimmer have just been cleaned the 1000 ppm Ca solution must be nebulized for about 10 minutes to deposit a layer of Ca oxide on sampler and skimmer to protect them from inadvertent exposure to hydrochloric acid Monitor the signal from 80 ppb Y La and Lu REEA solution and adjust the Barrel voltage until the Y and La signal are about equal This adjustment is normally very small The Y signal must not be significantly lower maxi mum 10 difference than the La signal NOTE The La counts should be about 70 to 110 KHz depending on the condition of the sampler and skimmer A newly Ca conditioned sampler and skimmer give 70 80 kHz During sample analysis as material is deposited on the sampler and skimmer the counts typically drift up over part or all of the REE mass range NOTE Using kHz as a unit for an ion signal is a good way of reminding one that the number which is presented as the intensity is a measure of frequency i e counts per second with which ions strike the detector For example the noise power spectrum of an instrument can be experimentally determined possibly giving insight to the source of signal noise in the instrument and perhaps uncovering ways to improve analytical precision 3 1 10 Adjust the Barrel lens so that the Y and Lu signals are maximized NOTE This procedure typically results in the signal strengths being skewed in favour of the lighter REE Adjusting the Barrel and Einzel vol
350. n No 40 filter paper into a 250 ml beaker Wash a few times with small portions of hot distilled water The paper with undissolved particles should be ignited in a Vycor glass crucible 30 ml Fuse the ignited residue with a small amount of potassium pyrosulphate K S 07 Dissolve the fused matter in the crucible by adding distilled water and a small amount of HCl Heat the crucible on a hot plate until the residue is in solution Transfer the solution to the original solution in a 250 ml beaker by washing the Vycor crucible a few times with small portions of distilled water 2 2 Reduction with stannous chloride 2 2 1 Heat to boiling on a hot plate the complete solution of the sample having a volume of about 50 ml or less 2 2 2 Add stannous chloride drop by drop until the yellow colour disappears Add one or two drops in excess 2 2 3 Coverthe reduced solution in the beaker with a watch glass and cool by placing in a tray having cold water 2 2 4 Add rapidly 10 ml of 5 HgCl measured in a graduated cylinder 2 2 5 A small quantity of white precipitate should appear 2 2 6 If no precipitate or if the precipitate is grey the sample should be discarded 2 3 Titration with KMnO 0 1N solution 2 3 1 After 2 or 3 minutes transfer the reduced solution quantitatively to a 600 ml beaker containing 25 ml of Zimmerman Reinhardt reagent and 300 mi of distilled water 2 3 2 Titrate immediately with KMnO
351. n Spectrometry with Hydride Generation Anal Chem Vol 54 pp 190 193 Chan C Y 1985 Semiautomated Method for Deter mination of Selenium in Geological Materials Using a Flow Injection Analysis Technique Anal Chem Vol 57 pp 1482 1485 Chan C Y and Baig M W A 1984 Semi automated Method for Determination of Selenium in Rocks Anal Letter 17 pp 143 155 Ruzicka J and Hansen E H Flow Injection Analysis Wiley Interscience Publishers New York 1981 EA26 3 Selenium Position 1 Sampling Heated Flow Rate Se Lamp Quartz Tube Eos Injection Valve m min Radiation Recorder Pd A C 2 12 rgon 53 HCl 2 1 Phenanthroline 3 0 0 1 NaBH Gas Liquid Proportioning Pump Impinger Separator Position 2 Injection 5 HCI 1 Ph th 1 NaBH Analytical Manifold for the Determination of Se by Automated Flow Injection and Hydride AA Techniques Figure Sel EA26 4 DETERMINATION OF MERCURY Mercury COLD VAPOR FLAMELESS ATOMIC ABSORPTION METHOD Introduction majorchallenge in Hg analysis lies in the preparation and storage of geological samples prior to analysis This is due to the high vapor pressure of mercury its presence in the atmosphere and the generally low levels in naturally occurring materials A number of procedures developed to allow for the above factors are detailed below Soil samples are normally collected at a depth of 4 t
352. n intermediate and acidic rocks Bismuth is generally less abundant than antimony Bismuth occurs as a minor component of massive sulphide segregations and in greater abundance in their derived hydrothermal deposits It is also reported to be present in apatite of igneous rocks and in many pematitic metamict minerals containing rare earth ele ments possibly in the ferromagnesian minerals or in plagioclase to some extent Arsenic antimony and bismuth are individually deter mined by a hydride generation atomic absorption method following sample decomposition This decomposition is accomplished in the following manner for arsenic the sample is fused with sodium hydroxide and brought into solution with hydrochloric acid for antimony the sample is digested with a mix ture of sulphuric and hydrofluoric acids and for bis muth the sample is digested in a mixture of perchloric and hydrofluoric acids Sodium borohydride solution is introduced to the sample solution by means of an automatic sampler and a proportioning pump The element of interest is con verted to its hydride which is separated in a gas liquid separator then swept by a stream of argon into an electrically heated quartz tube atomizer The atomic absorption of the element is measured Safety advisory 1 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manual page IV 17
353. n Flask B Pipet C Stopcock D Gas measuring Tube Levelling Bulb Magnetic Stirrer and Magnet Figure CH1 Chittick Gasometric Apparatus EA31 4 DOhiBick Ratio Calcite Dolomite Total 2 095 factor po xui 2 275 factor CO from Dolomite 2nd Reading ysis 3 x 2 Carbonate Anal by Form Mineral Research Branch IM Weight gm PG Dado Ministry of Ontario Sample No Natural Resources hj Form MS 013 09 74 yz
354. n by acid digestion with residue fusion if necessary 2 Measurment of absorbance by developing colour 3 Calculation of P O concentration based on a calibration curve produced by known standard solutions Apparatus Platinum or teflon dishes 50 to 100 ml teflon dishes are preferred due to lower cost and for higher productivity Glass volumetric flasks 100 ml Glass funnels 75 mm Filter paper Whatman No 40 and No 42 12 5cm Baush and Lomb spectronic 501 colorimeter Micro burette O 10 ml Reagents Ammonium molydate NH4 9M0o 0 4 4H O Ammonium metavanadate NH VO Boric acid crystals H4BO Nitric acid HNO 69 0 71 0 Hydrofluoric acid HF 48 Potassium phosphate monobasic KH PO Procedures 1 Reagent preparation 1 1 1 Ammonium molybate 5 stock solution Dissolve 50 g of NH4 gMo O 4 4H 0 in ap proximately 500 ml of warm distilled water and let stand for several hours 1 1 2 Filter through a 12 5 cm Whatman No 42 filter paper 1 1 3 Dilute to 1 liter with distilled water and store in a polyethylene bottle EA10 1 Phosphorus 1 2 1 1 2 2 1 2 3 1 2 4 1 2 5 1 3 2 1 3 3 Ammonium Metavanadate 0 25 stock solution Dissolve 2 5 g of NH VO in 500 mi of hot distilled water Cool and add 20 ml concentrated HNO3 Let stand for several hours and filter if not clear Dilute to 1 liter with distilled water Store in a g
355. n procedure After signing on the regression software the system waits for instruction SRI start regression input MODEL DJ R or DJ LOAD ALL ELEMENTS YE LOADED ELEMENTS SI AL FE 10 OF THE 10 SAMPLES LOADED inform operator of the number of standards in the file REGR ELMNT SI input element of interest To calculate the D and E values the operator types SRA and the system responds ELEMENT SI MODEL DJ SIGMA 0 01039 K 0 01358 D E 0 04110 1 25447 EA6 27 Majors XRF The SIGMA and K values indicate the quality of the fit The SIGMA is the standard deviation of the regression and is equal to aa SIGMA recur where C C is the square of the deviation betweer observed and accepted a concentration values number of samples and k number of regression coefficients the number of calculated influence coefficients alphas Thus if no alphas are included k 2 for a straight line calibration The K factor is related to the standard deviation and is inversely proportional to the overall concentration levels in the regression SIGMA C1 2 The regression program is arranged to reduce the K factor to a minimum If the k is too large for the number of standards being used in the regression an appropriate message will be printed out The overall quality of fit can be observed by typing PRL print results list The system will indicate the following INTENSITY observed
356. n the port and wait for the sample performed Samples are identified in the output by the tray number followed by the position number Samples 4 6 Load the sample into the waiting turret posi can be identified in a separate data file see manual or tion 1 samples can be identified using separate lists 4 7 Type the sample name Press R Care must be taken with the automatic sample changer The plastic trays and identification cards can be 4 8 The system will shut the port and bring turret sources of poor performance and both should be position 2 to the loading position In case of changed regularly New supplies should be ordered error i e sample mix up nosample etc the from Philips Electronics instruction can be cancelled by using the R command 5 1 Enter RES RESET to clear any previous condititions 4 9 Repeat steps 4 6 through 4 8 until all samples have been analyzed 52 Enter ASC 20 Assemble Sample Changer EA6 4 tray 20 In this case the system is informed that tray 20 is the last to be analyzed in the sequence In some Databanks MP1 involves the measurement of a Cu blank at reduced power for 10 seconds By having this sample in the first sample position of tray 20 with the card indicating MP1 the Cu blank is read and the sample changer sequence stops and powers the system down at the end of the run Majors XRF The MP to be employed is indicated on the i d card therefore it is possible to
357. nace atomic absorp tion spectrophotometry is well suited in the routine determination of these elements The natural abundance level for platinum is about 0 05 ppb which is approximately eighty fold lowerthan for gold Platinum tends be be slightly more abundant than palladium Gold platinum and palladium are determined in geological materials by graphite furnace atomic ab sorption spectrophotometry utilizing an autosampling system These elements are concentrated into a silver bead of approximately 15 mg by the classical lead fire assay method page M14 5 Dissolution of the silver bead is accomplished with nitric acid in a 10 x 75 mm test tube placed in an aluminum block and set on a hot plate The silver is precipitated as the chloride with hydrochloric acid whereby the gold platinum and palladium are dissolved in the aqua regia The acid mixture is diluted with distilled water mixed and the AgCl allowed to settle on the bottom of the test tube An aliquot of the supernatant liquid is atomized in a graphite furnace and the atomic absorption signal Observed as a recorder trace Safety advisory 1 The method involves the use of specific acids to dissolve the silver bead Personnel should review the MSDS sheets for these acids prior to use Method This method consists of the following techniques 1 Preparation of silver bead sample fusion and ex traction 2 Sample decomposition by acid digestion 3 Measurement
358. nally pressing ENTER Determine if the current program is correct by successively pressing the ENTER key to ad vance through the previously entered steps Place the crucibles into the holders and secure them by sliding the sleeve over the rims of the crucibles Place the molds in position and press the START button Whenthe cycle is complete 3 4 minutes use the tongs to remove the casting dishes and molds Remove the bead from the mold and label it with a gummed tag on the surface that was not in contact with the Pt Crack and re fuse imperfect beads rippled nonhomogeneous colour distribution etc EA6 9 Majors XRF Shut Down 1 2 16 Tum power ON OFF switch to OFF 1 2 17 Tum gas supplies off 1 2 18 Tum the fume hood off 1 3 Preparation of Pressed Powder Pellets for XRF Determination of Major Elements in Carbonate Rocks Samples of carbonate rock are prepared for XRF analysis as rock powder pellets Apparatus Ring press and die 40 mm Aluminum former sleeve Plexiglass plunger Boric acid measuring vial 25 ml Spex pellet press Model 3624B Reagents Boric acid granular Polyvinyl alcohol 256 w v in distilled water Procedure 1 3 1 Wearing gloves weigh 4 0 g 0 1 g of 200 mesh rock pulp into a 25 ml snap cap plastic vial Add three drops of polyvinyl alcohol solution to serve as a binder and blend into the pow der by stirring with a nickel spatula
359. nd trimmed to a depth of 1 cm at the point of maximum thickness With the use of a groov ing tool the soil is divided along the diameter through the center line of the cup 1 2 By turning the crank the cup is lifted and dropped at a rate of two revolutions per second until the two halves of the soil cake come into contact at the bottom of the groove along a distance of 1 3 cm The number of drops needed to close the groove fora distance of 1 3 cm is recorded 1 3 Part of the soil that flowed together is taken and placed in a container the wet weight is recorded and then the soil is oven dried to 110 C The sample is re weighed and the dry weight is recorded This procedure is dupli cated The procedure is repeated until the sample acquires a consistency that will require 25 10 drops to close the groove 2 Calculations k L1 Wt water x 100 x Wr dry soil where constant depending on the number of blows See Table ATT1 L1 liquid limit 100 Pl Wt water x Wi dry soll where Pl plastic limit TABLE ATTI CONSTANTS USED IN THE DETERMINATION OF ATTERBERG LIMITS No Blows k 10 0 906 11 0 913 12 0 920 13 0 927 14 0 934 15 0 941 16 0 948 17 0 955 18 0 961 19 0 968 20 0 974 21 0 979 22 0 985 23 0 990 24 0 995 25 1 000 26 1 005 27 1 009 28 1 014 29 1 018 30 1 022 31 1 026 32 1 030 33 1 034 34 1 038 35 1 041 36 1 044 37 1 047 Quality Control The GLOGS soil standard is analyzed on a
360. nd 104mRh gamma rays Peak areas corrected for background are compared for samples and standards Palladium platinum osmium ruthenium iridium and gold are determined up to 40 days after irradiation Samples ore standards and elemental standards are sealed in plastic irradiation canisters and irradiated for 16 hours Integrated peak areas corrected for back ground are used together with yields from crushing procedure decay constant irradiation time counting time and duration of count to determine the con centrations in the unknowns Full details of the counting procedure are provided at the SLOWPOKE reactor facility 3 4 Data Reduction Two IBM PC BASIC programs are used to reduce data they prompt the user for information and input data Copies of the programs are available from the Geoscience Laboratories Quality Control All samples and standards are analyzed in duplicate SARM 7 and at least one of the MRB standards MRB 19 through 23 are included with each batch of samples Bibliography Hoffman E L Naldrett Loon J C Han cock R G V and Manson A 1978 The Determina tion of all the Platinum Group Elements and Gold in Rocks and Ore by Neutron Activation Analysis after Preconcentration by a Nickel Sulphide Fire Assay Technique on Large Samples ANALYTICA CHIMICA ACTA Vol 102 pp 157 166 MS14 5 TABLE FA3 DETERMINATION LIMITS Element Rh Pd Pt
361. nd of the analysis place all feedlines in distilled water to flush system before tuming off the power on all modules Bibliography Ruzicka J and Hansen E H Flow Injection Analysis Wiley Interscience Publishers New York 1981 Technicon AutoAnalyzer Methodology Chloride Pro cedure Published by Technicon Instruments Corpora tion Ardsley New York 1966 EA24 3 Chloride Position 1 Sampling Sampler ps ids ml min Q 3 9 D dicc ole To waste Pump Position 2 Injection Sampler 2 Injection valve Recorder Colorimeter 3 9 E To waste Injection valve Recorder Colorimeter To waste 6x HNO 6 HNO Hg SCN Ferric nitrate 6 HNO 6 HNO Hg SCN 2 Ferric nitrate Analytical System and Reagent Manifold for the Determination of Chloride Figure EA24 4 As Sb Bi THE DETERMINATION OF ARSENIC ANTIMONY AND BISMUTH HYDRIDE GENERATION ATOMIC ABSORPTION METHOD Introduction Arsenic appears to follow sulphur quite closely and as aresult readily substitutes for sulphurin many sulphide minerals Perhaps the best known arsenic bearing mineral is arsenopyrite In ultrabasic rocks arsenic concentrations are typically 3 ppm while this decreases to about 1 ppm in intermediate rocks Antimony is less abundant in the earths crust than arsenic It too is closely associated with sulphide minerals but often shows higher concentrations i
362. ndex RI of Canada balsam RI 1 537 For example rutiles have a high relief whereas quartz has a low relief The Becke line test may be applied to determine whether low relief minerals have higher or lower refractive indices than Canada balsam Under similar light conditions to those described above low or moderate relief minerals concentrate light as a thin bright white line along their margins This line termed the Becke line will move inwards or outwards if the mineral grain is brought slowly into or out of focus The Becke line moves into the substance of higher RI when the dis tance between the objective and section is increased A more accurate means of determining RI involves the use of loose or crushed grains of a mineral in a series of liquids of known RI The relief of the mineral will disappear when its RI matches that of the liquid A small amount of the mineral is crushed to a powder and placed on a glass slide The powder must be neither to fine nor too coarse as a fine powder is too hard to observe yet a coarse powder will tend to float A glass slide is placed on the dry powder and the RI liquid is introduced at the margin of the coverslip using a dropper The procedure is repeated with dif ferent RI liquids until the RI of the mineral is matched to that of the liquid When the RI of the mineral is within 0 002 of the RI of the oil colored Becke lines are seen 9 1 MiNeETology RI liquids a
363. ned for each analyte of interest under CAL naming convention e g 002 CALOO4 The standards on the following page are used When system restandardization is required the option CA has to be included in the AN analysis mode With the same plasma source conditions the gains and Offsets associated with the restandardization calcula tions should change by less than 10 generally within 5 However if the change is greater than 10 the following operating parameters should be considered and checked nebulizer clogging changing plasma gas flows contamination of standards incorrect measure ment conditions integration time etc peristaltic pump problems incorrect PMT resistance settings exhaust fan problems incorrect slit position misiden tified calibration standards uncleaned torch etc Element Lowstd Conc Highstd Conc Tungsten 1 0 8 10 Beryllium 2 0 3 0 1 Cobalt 2 0 4 10 Nickel 2 0 4 10 Copper 2 0 4 10 Vanadium 2 0 4 10 Strontium 2 0 4 10 Scandium 2 0 4 1 Yttrium 2 0 4 1 Molybdenum 2 0 4 1 Zinc 2 0 5 10 Barium 2 0 5 10 Chromium 2 0 5 10 Niobium 2 0 5 1 Zirconium 2 0 5 1 Cerium 2 0 5 1 Magnesium 2 0 6 500 Phosphorus 2 0 6 50 Iron 2 0 Calcium 2 0 7 1000 Aluminum 2 0 7 1000 Titanium 2 0 7 80 Manganese 2 0 7 80 Tantalum 2 0 10 10 Lead 2 0 9 10 Lanthanum 2 0 9 10 Neodymium 2 0 9 10 To monitor the drift of the instrument check solutions are usually run every 10 15 samples within a batch analy
364. nel for the separation of paramagnetic minerals and the side slope is forward away from the pole pieces The chute is angled so that the top end is under the pole pieces and the bottom end outside of them The gate at the bottom end of the feed hopper and the vibra tion of the hopper are adjusted so that flow rates are about 5 ml per minute in the final stages a feed rate of less than 1 ml min is appropriate The vibration of the chute is also adjusted so that the travel time of grains from one end to the other is about 30 s 1 7 1 8 1 9 The initial magnetic setting is dependant on the sample but 0 1A is normally used The current is increased on successive passes Once the more magnetic minerals which could clog up the chute have been removed the sample may be run at a current high enough to divide it into two equal fractions with the mineral of interest entirely in one This will speed up processing particularly if the sample is large Also relatively high flow rates can be used as the deterioration in the separating ability of the Frantz is not of great concern at this stage The sample volume is halved on each successive pass until the mineral of inter est is concentrated Note that in the separation of diamagnetic minerals the feed is into the outer channel of the chute which is sloped in toward the pole pieces The final stages of the separation take place at much slower feed rates so that the separation is precise and
365. ng agreements were obtained where Exp expected Zr values based on Govindaraju 1989 Calc Zr determination based on calibration over full concentration range Calc Zr determination based on limited concentration range i e excluding NIM L EA16 5 Traces XRF Standard Exp Calc Calc ppm ppm ppm MicaFe 800 753 810 NIM L 11100 11080 N A GA 150 133 139 SY3 320 330 320 MAN 27 29 36 MRG 1 105 106 113 GH 150 119 132 BEN 270 348 271 The agreement between Exp and Calc indicates calibration over more limited ranges is preferable The disagreement between Exp and Calc could be assigned to various factors including wide range of calibration with assumption of linearity over the total range from 27 to 11 000 ppm questionable accepted values limited data for calculation of alphas applicability of the utilization of the Rh Compton line for the mass absorption correction The applicability of the Rh Compton line can be assessed using the program on page EA16 9 which calculates the mass absorption based on background counts MA B Compton counts MA C and major elements MA Majors Analysis of calibration intensity data results in the following data based on the mass absorption of SY3 for Sr being 12 6 Reference MA B MA C MA Maj MAN 11 2 7 22 7 81 NIM L 10 0 16 5 12 8 Mica Fe 13 3 21 1 19 7 GH 11 7 7 17 9 40 MRG 1 13 7 18 2 17 6 QTZ 13 2 8 22 7 34 SY2 13 0 11 9 12 0 G1 12 0 8 11 9 33 DRN 13
366. ng of the reading min 8 3 The percentage of particles of size 2 25 MS4 12 microns or less SL is calculated from a plot 9 of percentage of soil in suspension against the diameter of the soil particles The percentage of particles with sizes between 710 and 2000 microns The weight percent of sample from the 14 18 and 25 sieves can be used to calculate the weight percent contribution in each of these grain size intervals i e A wt retained on No 14 100 etc 10 The percentage of particles PL with sizes be tween 2 25 and 65 microns is determined by PL W A B C D SL 100 where PL percentage of particles being ana lysed by the wet sensor W original weight of sample in grams prepared for grain size analysis not hydrometry A B C and D percentage of sample retained on No 14 18 25 and 230 sieves re spectively i e weight 100 SL percentage of particles with grain 11 sizes less than 2 25 microns deter mined from hydrometry The contribution of particles in each grain size interval determined by the wet sensor is then cal culated by multiplying the percentage in that chan nel for each of the 32 channels by the overall percentage of particles analyzed by this sensor PL The percentage of particles with sizes between 65 and 710 microns This is determined by multiplying the count in each of the 32 channels by the percentage con tribution by
367. nited oxide porous texture which aids in oxidation of iron to Fe O NOTE It may be necessary if there was much acid retained by the paper to add a few drops of aqueous ammonia to the solution 4 2 8 Rinse down the sides of the beaker and heat to boiling for 1 min Allow the precipitate to settle and filter as before combining the two filtrates in the 600 mi beaker EA8 6 4 2 9 Carefully police the beaker and stirring rod using the NH NO wash solution and wash the paper and precipitate 6 8 times with hot 2 NH NO wash solution 4 2 10 Wipe the lip of the beaker and stirring rod with a small piece of filter paper 4 2 11 Cover funnel with filter paper and set aside until ready to ignite 4 2 12 Reserve filtrate for determination of Ca and Mg 4 3 Ignition of precipitate 4 3 1 With the platinum tipped forceps carefully lift the paper containing the bulk of the precipitate from the funnel and place it in the platinum crucible used for the determination of silica 4 3 2 Fold the upper edges of the paper over the precipitate avoid soiling the sides of the crucible because after ignition it is difficult to remove these stains during the pyrosulphate fusion NOTE As stated above the residue from the silica consists of Fe Al and Ti oxides These belong to the ammonia precipitate and therefore the later is ignited in the crucible with the silica impurities Wipe the upper edge
368. nk x 366 Micrograms sample 3 Shutdown 3 1 Switch off the air pump of the CO apparatus 3 2 Disconnect the scrubber outlet line 3 3 Tum off the heater 3 4 Tumoffthecell current and coulometer power 3 5 Unplug the electrodes and remove the cell from the holder 3 6 Dispose the coulometer solution and rinse the cell body 3 7 Remove the silver electrode and rinse with water 3 8 Rinse the outside of anode compartment gas inlet tube and Pt electrode with distilled water 3 9 Rinseouttheanode compartment with acetone Remove KI and deposits on top of the glass frit 4 Maintenance 4 The cell solutions should be replaced if over 100 mg of carbon have been titrated 4 2 Ifthedeposits stick in the glass frit pull acetone through frit with aspirator or other vacuum source or clean it with ultrasonic cleaner Anode deposits can be removed with a saturated KI solution 4 3 If a deposit is evident on the platinum electrode this should be dissolved in 1 1 44 The cell current switch should be turned off whenever the cell is disconnected 4 5 A high blank result is usually the result of exhaust KOH solution in air scrubber Replace the solution when this happens Quality control The optimum working range for this method is 0 01 20 The determination limit for CO is 0 01 in rock although the system is capable of detecting as low as 0 003 Precision expressed at the 95
369. nto a cube MS14 2 1 12 1 13 1 15 1 16 1 17 1 18 Place the lead cube on a preheated cupel 950 C and heat in the furnace for ap proximately half an hour until lead is ab sorbed in cupel Remove the silver prill and note any peculiarities Brush and accurately weigh the silver prill using a fine balance to 0 1 mg Place the prill in a parting dish Digest silver prill in hot nitric acid and wash the residue with distilled water fume hood operation Anneal and then accurately weigh the gold using a fine balance to 0 01 mg Record all observations and results in a daily log Calculate silver weight and record gold and silver results in report Assuming 1 2 assay ton multiply the weight Ag in g by a factor of 2 and convert to oz ton by division by 29 166 Quality Control The determination limits for this method are 0 01 oz ton for Au and 0 10 oz ton for Ag The precision 2 at 10 times determination limit for Au is 0 01 oz ton and 0 10 oz ton for Ag Precision and accuracy are monitored by measuring the concentrations of gold and silver in at least one duplicate sample from each batch and by analyzing the MRB gold silver standards MRB25 28 on a monthly basis Proposed in house certification data for these standards are TABLE FA2 Standard Gold Silver oz ton ppm oz ton ppm MRB25 1 44 49 2 2 75 MRB26 0 37 13 10 1 346 MRB27 0 016 0 5 45 1 1546 MRB28 1 45 50 94 5 3240
370. o 6 inches As the Hg concentration in soils often varies considerably within a soil profile a standardized depth of collection is important In areas with a thick organic horizon such as British Columbia samples should be collected below the obvious organic horizon If the soil samples are dry they should be sieved to 80 mesh in the field using a stainless steel sieve and stored in air tight screw top glass vials Wet samples should be dried at room temperature or in the shade before sieving Heat lamps should not be used as this could result in volatilization of Hg from the sample Rock samples should not be ground in a ceramic plate mill The heat generated by such grinding tends to volatilize a significant portion of the included Hg especially in samples containing sulphides Instead rock samples should be coarsely crushed in a jaw crusher and the 20 mesh fraction removed This fraction should then be hand ground to 80 mesh Sample pulps should then be stored in air tight glass vials The sample is digested at low heat with nitric and hydrochloric acids The digested sample and stannous chloride solution are continuously pumped through a mixing coil and into a gas liquid separator Mercuric ions present in the solution are reduced to elemental mercury The volatilized mercury is separated and swept by a stream of argon into the absorption cell of aLDC Milton Roy Mercury Monitor where the atomic absorption at 253 7 nm is me
371. o Manual switch box Auto 2 Calibration and Sample Analysis Samples containing 0 2 7 Carbon 0 10 and 0 0 8 Sulphur are analyzed by the following steps 2 1 Tum the oxygen cylinder on and adjust the pressure to 35 psi 2 2 Add 1 scoop of vanadium pentoxide ac celerator to a crucible 2 3 Place the crucible on the balance pan and press the TARE switch on the AWC control box 2 4 Add 0 3 g 0 4 g of reference material to the crucible 2 5 Press the ENTER switch on the AWC Control Box the red WEIGHT IN light will activate 2 6 Add 1 scoopofiron accelerator and 1 tin pellet to the crucible 2T Cover with a lid and place the loaded crucible on the pedestal of the induction furnace 2 8 Set UP DOWN switch to UP to begin the analysis cycle while the sample is being heated a second sample can be weighed 2 9 When the CARBON and SULPHUR READ lights glow red indicating complete analysis Record the C and readings If the values deviate from the standard expected value the function switch of the determinator should be rotated to the CALIBRATE position and EA13 2 the calibration dials adjusted to obtain the desired readings 2 10 Reanalyze the reference material at least three times until the readings are consistent with values expected see QC section 2 11 Lock the calibration dials and rotate the func tion switch back to the OPERATE position the instrument is now ready for sample
372. o and fa J In 3 CaO MgO FeO 2SiO for diopside wo en and fs if SiO is insufficient dis tribute between x molecules diopside y molecules akermanite 2CaO Mg Fe O 2SiO and y 2 molecules olivine given by 2x 2 5y available SiO and olivine formed to I N B Akermanite is recalculated in the norm as both the ordinary akermanite molecule Ca MgSi O and the Fe akermanite molecule Ca FeSi O in a manner similar to that for olivine If silica is insufficient for stages A I create the normative molecules in A I and akemanite and olivine in J and declare the silica deficien cy Si def if however silica remains then continue allocation of SiO L ZrO SiO for zircon if no silica or insuffi cient then remainder of ZrO for baddeleyite M In 10 510 for sphene or as far as possible remainder left as pervoskite CaO TiO N Convert B to K 0 A1 03 4SiO for leucite or if possible K O A1 0 6SiO orthoclase Gf the available SiO is not sufficient for the conversions then distribute between x molecules leucite and y molecules kalsilite given by x y available and 4 2y available SiO or between x molecules or thoclase and y molecules leucite given by x y available K O and 4y available SiO as appropriate Convert C to Na O Al 03 6SiO for albite if insufficient SiO then distribute between x molecules albite and y molecules carnegieite whe
373. o dissolve Development of a method employing steel clad teflon lined bombs may yield a method that would open out these minerals The presence of sulphide minerals at levels greater than 896 in the sample may introduce determinate error and a resulting high bias in the results Sulphur can reduce some of the If accurate results are required it may be necessary to develop a method where the samples are ground in an inert atmosphere using tungsten carbide or other suitable grinding material EA15 4 Productivity A technician should be able to complete 30 samples per day Additional Notes Efficiency is improved if samples are run in sets of two Two samples are weighed and queued for analysis During the ten minute analysis time for these samples the next two samples can be weighed and if required may be added 2 Always keep plenty of hot distilled water on hand This water is used for making the saturated boric acid solution 50 ml per sample It is convenient to use three separate one litre beakers for this purpose The first is boiled and removed from the hotplate While it is cooled the second is placed on the hotplate to boil When the first is cool 50g of boric acid are added When the second has boiled it is removed from the hotplate and allowed to cool The third follows the second through this process When the first solution is used the first beaker follows the third and the cycle continues
374. obtain total SiO 4 Determination of All Fe Al Ti and P 4 1 precipitation 4 1 1 The filtrate from the second silica filtration is used which should be in a 400 ml beaker NOTE All of the iron present in this filtrate is in the ferric form due to oxidation during fusions and evaporation 4 1 2 Add 5 6 g of NH4CI depending on the amount of Mg likely to be present and dilute the solu tion to 200 ml NOTE is added to prevent precipitation of Mg OH with the Fe and Al The more Mg present the greater the amount of NH4CI needed 4 1 3 Most of the free acid is neutralized by adding pure NH4OH from a small beaker If the solu tion is dark coloured indicating the presence of much iron there is no point in adding a pH indicator if the solution is light coloured add 3 drops of 0 2 methyl red 60 alcoholic solution pH 4 2 6 3 Majors Classical Heat to boiling reduce the heat and then add pure aqueous ammonia from a dropping bottle until a permanent precipitate forms stirring vigorously at all times 5 The precipitate will appear textureless until near the end point at which stage it will coagu late If an indicator was used the supernatant liquid will be yellow at the end point If an indicator was not used the neamess of approach to the end point can be tested for by adding a drop of the indicator to the quiescent solution and noting the colour of the drop as it stri
375. of HF 48 and 10 ml of 1 1 H5SO Digest and evaporate to dense fumes of SO for 5 minutes Cool wash the sides and evaporate again to dense fumes of SO for few minutes 2 to 3 3 9 3 10 3 11 3 12 3 14 minutes Fluoride ions interfere with the titanium determinations by bleaching the yel low colour Therefore it is important to expel fluoride by fuming with H2SO Cool add 25 ml of distilled water cover and heat on hot plate until sample is dissolved 30 minutes approximately If the sample is high in Ca Ba and Mg insoluble sulphates of these elements will be formed and will not be dis solved Filter using Whatman No 42 12 5 cm filter paper ina 100 ml volumetric flask Wash the platinum dish several times with small portions of 5 H SO warm and trans fer all the washings to the filter paper Wash the filter paper several times with small portions of 5 H SO wash solution Ensure volume in the 100 ml flask after wash ings does not exceed 75 ml This is your original solution to develop and measure colour 4 Measurement of TiO concentration 4 1 4 3 Add 5 ml of phosphoric acid H PO to the original solution in 100 ml volumetric flask and shake well the colour due to ferric sulphate is bleached by the addition of phosphoric acid Add 10 ml of 3 solution made fresh of hydrogen peroxide H5O mix and make up to 100 ml with distilled water Measure the absorbance d
376. of the funnel with a small piece of filter paper and add it to the crucible also 4 3 4 The bulky precipiate should be partly dried or at least well drained before being placed in the crucible if not there is danger that entrained liquid will boil and some precipitate will be lost by spurting Partly cover the crucible and place it in a cold electric muffle furnace Allow the temperature to rise slowly and en sure that there is free access of airto the furnace during the initial stages of the ignition Finally heat at just below 1200 C for 40 minutes cover the crucible cool and weigh as usual When much iron is present it is a useful precaution to transfer the crucible from the muffle fumace to the full heat of a Meker burner for 5 minutes with the lid displaced to allow free access of airto the crucible to ensure that oxidation of iron is complete there is little likelihood of the ignited Al O absorbing water having been heated at 1200 C 4 3 8 Repeat ignition for 20 minutes until constant weight is obtained 4 3 9 From the total percent of the RO oxides the precentage of Al O is obtained by subtracting the percentage of the other constituents of the group in particular those for total iron as Fe 03 TiO and residual SiO NOTE Because of number of subtractions from the precipitate due to presence of Fe O P Os residue SiO and other impurities the ALO value will not be suitab
377. off the Envision terminal printer depress the DISCS button and turn the com puter power off NOTE This must be done at the end of every day otherwise there is a chance of damage to the computer 9 Instrument Shut down Emergency Shutdown Emergency situations previously encountered include broken water gas lines and grinding noises from the cryopump 9 1 1 Depressthe big RED buttonon the front of the torch stand or RF generator 9 1 2 Depress the Operation button OFF EA19 12 9 1 3 Tum off the detector 9 1 4 Tumoffthe water to the interface and the load coil In cases where the situation is considered serious quickly shut down the power to the instrument using the breaker switch located outside room 1019 Panel C Switch 2 or turn the power button OFF located on the front panel of the instrument NOTE When powering back up the emergency lock clasp on the red button must be released or power will not be restored using the normal start up sequence Push the red button in and turn slightly it will pop back out into the normal position Temporary Loss of Cooling Water Occasionally the building water supply is turned off Since the cryopump must have cooling water to run the instru ment is best put into cryoclean cryopump is not re quired for the duration of the interrupted service A full pumpdown from atmospheric will be required after 2 3 hours TRACE 4 T4 ELEMENTS Tra
378. ogist requires detailed whole rock geochemical analysis Samples submitted in batches for whole rock analysis are usually given a job number Safety advisory Refer to the safety advisory as detailed in the Assay Preparation method Page M1 1 Technique Whole rock sample preparation involves the following procedures 1 Sorting of samples in preparation for grinding 2 Determining specific gravity for each sample 3 Crushing the samples sequentially using a jaw crusher retaining a hand sample 4 Riffling to split sample retaining one split for grinding and another split as a back up 5 Grinding the split in a mill on a planetary ball mill for an appropriate length of time 6 Sieving the pulp and re grinding the material gt 170 mesh 7 Removing pulp after grinding onto glazed paper and transferring to labelled bottle General comment Ensure that equipment is cleaned before and after use with quartzite as a cleaner and compressed air in the blow out area The grinding area should be kept clean by using the central vacuum unit Apparatus Containers for laying out the samples on the bench top in a systematic fashion Balances forthe determination of specific gravity Small jaw crusher with steel plates Riffle to split samples Planetary ball mill 99 8 pure alumina 170 mesh nylon sieve Central vacuum unit 51 4 The Braun pulverizer equipped with ceramic plates is sometimes used fo
379. oined as contact twins on a plane or as penetration twins MS8 2 OPTICAL MINEROLOGY Introduction Rock and mineral samples are examined under the polarizing optical microscope as thin sections or grains to allow examination of rocks in transmitted light Procedures 1 Preparation of thin sections 1 1 Asmallchipof rock or mineral is sampled a thin slice 5 mm thick is cut from the specimen using a diamond saw 1 2 The chip or slice is ground flat and smooth on the surface using progressively finer abrasive e g Carborundum powder starting with 80 grade and finishing with 600 grade 1 3 The smooth surface is cemented to a glass slide usually 2 x1 using Canada balsam or Lakeside 70 cement 1 4 The other surface is ground down until the rock section is 300 microns thick Progres sively finer abrasives are used as the section becomes thinner and finishing is done with 600 grade Carborundum powder The thick ness is gauged by observing the interference colours of common minerals such as quartz or olivine 1 5 After cleaning excess cement from the surface of the section it may be covered with a glass slip cemented in place with Canada balsam Canada balsam may be thinned with xylol to ease spreading The mounting is done on a hot plate which serves to drive off xylol and harden the cement Some poorly consolidated samples require impregna tion with a cement before a section can be made Heating
380. ol 5 2 10 Using the Na and K Cal controls adjust the two readouts to values corresponding to the standard being aspirated first start with 15 ppm adjusting to read 150 on read out Then adjust the values for other standards NOTE l Insert the standard every tenth determination to check calibration 2 Steps 5 2 1 to 5 2 10 should be repeated every 30 minutes or less as the user determines on the basis of experience 5 3 Run samples Remove the Na K standard Place a sample cup of unknown on the sample tray Raise the tray to the limit stop The display switch can be left set to continuous which allows a sample to be monitored as long as sufficient fluid remained in the sample cup Readings can be taken when the operator feels that they have reached stability usually 10 12 seconds after insertion of the sample EA11 4 Alternatively the operator can set the mode switch to Delayed Hold In this condition raising the sample tray initiates a timed sequence in which the readouts indicate freely for 15 seconds allowing time for both Na and K readings to stabilize After this delay the readings are held Loss of reading will not occur until the sample tray is lowered and raised again 6 Calculation of the results 6 1 Calculation of results is based on 0 125 g sample weight which is made to 250 ml 250 100 18480 Na O ug Na ml 10 225 x Ro 1 2046 K0 ug K ml x sampe WE 10
381. olution Prepare 1 liter of this solution by mixing 50 ml of concentrated with 950 ml of distilled water 2 Sample decomposition and ignition of residue 2 1 Weigh exactly 0 500 g of sample and transfer to a 150 ml beaker 2 2 Slowly add 50 ml 1 3 Swirl occasional ly 2 3 When vigorous effervescence has ceased heat the contents on a hot plate to near boiling Digest for 15 minutes at a temperature just below boiling 2 4 Filter at once through a 11 cm Whatman No 40 filter paper and wash the paper and residue thoroughly with hot dilute HCl 5 95 2 5 Transfer the paper and residue to a weighed porcelain crucible 2 6 Burn off the paper at 250 to 300 C and then ignite the residue at 900 1000 C for 15 minutes 2 7 Cool in a desiccator for half an hour and weigh 3 Calculation of the results The content of acid insoluble residue or acid in solubles is calculated according to the equation Acid Insolubles 2 w wj x 100 where w weight of crucible in g W2 weight of crucible and residue in g after ignition EA30 1 Insoluble Residue Quality control The determination limit for this method is 0 2 The precision at the 95 confidence limit 26 is X596 relative Accuracy has not been determined since a suitable standard reference material is not available Productivity A technician should be able to complete 20 determina tions per day EA30
382. olution into a 200 ml volumetric flask and make to volume with 10 HNO3 see Note 1 4 1 2 Pipet20mlofthe 100 ppm Ru and Re solution prepared in 4 1 1 into a 200 ml volumetric flask and make to volume with 10 nitric acid Store solution in a polypropylene bottle 4 2 Preparation of mixed acid solutions 4 2 1 Solution A Mix 400 ml of HF 40 ml of HCIO and 40 ml of HCI and store in a polypropylene acid dispensing bottle see Note 2 CAUTION Be aware of the hazards noted at the beginning of this section dealing with hydrofluoric and perchloric acids 4 2 2 Solution B Add 30 ml of and 70 ml of HCI to 380 ml of distilled water and store in a polypropylene acid dispensing bottle 4 3 Weigh 0 200 g of sample into a 50 ml PTFE beaker 4 4 Add 12 15 ml of solution A to the samples and swirl the beaker to ensure complete wet ting of the sample 4 5 Place the beaker on a hotplate set at 180 C and evaporate to dryness overnight 4 6 Gently tap the beaker to allow any droplets of acid condensed on the upper portion of the beaker walls to fall to the bottom Sample Dissolution 4 7 Place beaker on hot plate until acid fuming ceases 4 8 Repeat steps 4 6 and 4 7 until all acid has been removed 49 15 ml of solution B to the dry residue place beaker on the hotplate and evaporate to dryness overnight 4 10 Repeat steps 4 6 to 4 8 see Note 3 4 11 Add 1mlof HNO to the dry
383. om ponents include the following Heating bath equipped with electric heating bar thermo regulator and motor driven stirrer 15 ft Teflon coil 1 8 i d immersed in the silicone oil contained in the heating bath rotary vacuum pump with vacuum gauge and regulator fractionation column of borosilicate glass water jacketed condenser distillate collector waste condenser and trap assembly D Cartridge consisting of housing which supports the reagents tubing manifold mixing coils connectors and fittings E Voltage stabilizer Reagents Sodium hydroxide pellets NaOH fluoride Perchloric acid HCIO 1 1 Sulphuric acid H5SO 1 1 Acetone buffer pH 4 0 Acetone lt 1 ppm EA23 1 Flouride Alizarin fluorine blue Lanthanum nitrate stock solution Brij 35 wetting agent 30 solution Alizarin reagent EDTA reagent 1 w v Stock standard flouride solution Working standard solutions Procedures 1 Reagent preparation 1 1 1 2 1 3 1 1 4 1 1 4 2 1 4 3 1 5 1 6 1 1 6 2 Perchloric acid HCIO 1 1 Mix 500 ml of perchloric acid 70 with 500 ml distilled water Sulphuric acid H5SO 1 1 Carefully add 500 ml of concentrated sulphuric acid to 500 ml of distilled water Mix and cool to room temperature before use Acetate buffer pH 4 0 Dissolve 60 g of Sodium acetate trihydrate in 500 ml of distilled water Add 100 ml of glacial acetic acid
384. omplete thirty grinds samples per day Whole rock Preparation MS1 5 Carbonate Preparation CARBONATE AND TRACE ELEMENT PREPARATION FOR SOILS Introduction This sample preparation procedure is used to prepare soil and regolith samples for Chittick analysis major analysis and or trace element analysis as described in The Elemental Analysis Section of this manual Procedure 1 1 The dry sample is hand broken to pass No 10 mesh sieve Special care is taken not to crush any larger particles in the soil sample The amount of sample dried depends upon the grain size 12 Soil passing the No 10 sieve is thoroughly mixed until homogeneous Portions of this mixture are sieved through No 80 and No 200 sieves Material passing No 200 is kept for carbonate analysis 12 15 g 1 3 Another portion is sieved through number 120 and 400 sieves Material passing No 400 is kept for trace element analysis 12 15 g Sieves No 80 and 120 are used to protect the fine mesh of the No 200 and 400 sieves MS2 1 Conodont Preparation CONODONT SEPARATION AND PREPARATION Introduction Conodonts are microfossils They are used to establish the age of the strata in which they are found and to correlate rocks in different areas Procedure 1 1 Crumbie the sample gently between two layers of clean paper 1 2 Transfer the sample to 3or4 liter beaker and cover with water for 2 3 days Decant 1 3 Add commercial
385. on calculations No addi tional input is required until the final results are printed 3 9 The program will prompt for the number of the instrument QC solutions that were run and their positions in the run Enter the correct information The program will calculate and produce a report summarizing the instrument QC data This information is presented as the difference between the observed and the expected values divided by the standard deviation associated with the expected value If the error is normal ly distributed then 66 of the results should EA19 15 Traces ICP MS be between O and one standard deviation Less than 0 546 of the results will be greater than 3 standard deviations when there is no analytical bias associated with the measure ment Thus if such an occurrence is observed there is good reason to believe that the meas urement is biased A run or data between check samples will be rejected if more than twoofthe check samples lie outside 3 standard deviations The program will calculate and produce a report summarizing the preparation QC data This information is presented in a manner similarto that produced forthe instrument QC The program will ask whether the concentra tion data are to be stored Respond ap propriately If the data are not to be stored the program will retum to the CONCAL main menu If the data are to be stored four options will be presented 1 Routine Sample Data Storage
386. ons or additions require a attack Any element determined by ICP OES re quires this acid attack Any assay sample requiring elements of the T1 options which will be determined by Flame AAS only may use HCI HF HNO acid attack Requests for silver and cadmium require an acid digestion without the presence of HCI Requests for a T4 or TS package require a detailed HNO HCIO HF attack Vegetation samples require dry ashing followed by mineral acid attack Fusions l Samples requiring the determination of tin are fused with lithium metaborate by the sample preparation group and passed to ICP MS for deter mination Sample residues which indicate incomplete acid attack are fused with an appropriate flux The indication may be visual or after Screen evalua tion For accurate work use an acid attack followed by a fusion of any residue using a minimum of flux The two solutions are combined and analyzed by the appropriate technique NOTE Solutions presented to ICP OES and ICP MS must indicate the approximate total salt con tent Samples known to contain high barium barite and chromium chromite are fused with lithium metaborate without prior acid attack If the chromium content is 5 sodium peroxide is used as the flux Only Flame AAS is used for measure ment when the salt content of the solution is high EA 1 2 Selection of Sample Weight Volume 1 A 0 500 g sample dige
387. ontain ing carbonate minerals are siderite or chalybite FeCO and ankerite which is a mixed carbonate or iron cal cium and magnesium In this method the reduction of Fe to is achieved by stannous chloride in a hot acid solution the excess of which is removed by the addition of mercuric chloride prior to titration The sample solution is then titrated with standard potassium permanganate solu tion The concentration of Fe is calculated on the basis of the net volume after blank subtraction This method is used only where the sample matrix makes determination by XRF unsuitable e g when the sulphur content of the rock is too high to allow a fused bead to be prepared for XRF determination This method is also applied when the total iron content expressed as Fe O is 21596 above the calibration range of the current XRF method This method is also applied for accurate determination where a standard reference material has to be analyzed for certification purposes Platinum vanadium copper arsenic antimony and molybdenum are reduced to a lower valence state like iron with the addition of stannous chloride and titrated with KMnO solution If present in appreciable amounts the Fe concentration will appear higher than the true concentration Safety advisory 1 When using HF wear glasses and gloves and be extremely careful More information on HF is available in the Geoscience Laboratories Safety Manu
388. ontamination and recover mineral mix tures when they are split Hand magnet to remove ferromagnetic minerals Plastic vials to store the various mineral fractions Compressed air brushes etc for cleaning the instrument Titanium tipped tweezers Reagents None required Procedures 1 1 The rock sample is reduced to its component mineral grains by crushing it in a jaw crusher followed by pulverization in a mill In the Braun pulverizer several passes reducing the gap between the plates each time are neces sary to avoid too much fine material A roll mill if available produces a better result as the crushing action here as opposed to the ripping action of the former results in more liberated grains A hand magnet should be passed over the sample at this stage to remove iron filings and magnetite which could stain the other minerals These should be saved in case they are needed at a later time The hand magnet should be in a plastic bag so that the poles are not coated by the magnetic particles alterna tively an enclosed plunger type magnet may be used MS7 2 1 3 1 4 1 5 1 6 The sample is placed in a deep container and washed in water to remove the rock flour Swirl the water through the sample and let stand still for 15 20 s before decanting the water Be careful not to lose micas when decanting they often float on the water sur face as a result of surface tension effects Washing should continu
389. or Coulometrics CO Deter minator Coulometrics Incorporated Chan C Y 1986 Determination of Carbonate Carbon in 41 International Geochemical Reference Samples by Coulometric Method Geostandards Newsletter Vol X No 2 pp 131 134 Huffman E W D 1977 Performance of a New Auto matic Carbon Dioxide Coulometer Microchemical Joumal Vol 22 pp 567 573 EA28 3 Carbonate Carbon Te eC Detector cell Light source Cell body Gas inlet Gas outlet Anode compartment Frit Stirrer Platinum electrode cathode Cathode terminal Silver electrode anode Anode terminal O c o0 e o o 09 9 Figure CC1 Coulometer cell EA28 4 DETERMINATION OF MOISTURE Introduction Minus water H O ormoisture is the portion of water in rocks held by surface forces such as adsorption and capillarity It can be driven off at 100 110 C The H O content is determined by measuring the loss of weight of a 1 g sample when it is dried overnight at 110 C Safety advisory 1 No specific safety advisory is required for this method Method 1 Direct gravimetric determination of loss on heat ing 2 Calculation based on sample weight loss Apparatus Drying oven Porcelain crucible with lid Desiccator Reagents No reagents are required for this method Procedures 1 Direct gravimetric determination of H O 1 1 Weigh 1 0000 g of sample and transfer
390. os phate NH HPO to give approximately 1 g of the reagent per 100 ml of filtrate with 1 g in excess Stir and add with vigorous stirring sufficient concentrated aqueous ammonia to make the solution 10 by volume in aqueous ammonia and continue to stir until precipitation begins Allow to stand overnight in a fume hood NOTE When any soluble ortho phosphate salt is added to an ammoniacal solution containing Mg and ammonium salts the Mg is precipitated as white crystalline MgNH4PO When this compound is precipitated the first time from the calcium filtrate it is usually impure due to the presence of large amounts of ammonium and sodium salts inthe solution This is rectified by dissolving the precipitate and re precipitating under better conditions NOTE Avoid striking the walls of the beaker with the stirring rod during stirring The abrasion of the glass surface encourages the growth of fine 6 1 5 6 1 6 6 2 6 2 1 6 2 2 6 2 3 6 2 5 6 2 6 6 2 7 6 2 8 crystals of the precipitate on the walls of the beaker When only a small amount of Mg is present however precipitation can some times be initiated in this fashion Filter the solution through 12 5 cm Whatman No 42 filter paper into a 1000 ml beaker preferably in front of a fume hood The bulk of the precipitate should be kept in the beaker Wash the beaker and precipitate twice with 596 aqueous ammonia v v and pour the was
391. ound or interferences computer controlled access of DAT files for implementation of regression routines detection limit calculations all programs routines RAW DAT files are stored on floppy disks Computer Management Software Control Introduction to the Computer The DEC 11 23 system is used for instrument control and for data processing and management using software available from the manufacturer Because the application software is written in FORTRAN lan guage externally developed programs can be used to access the datafiles produced by the system and the computer used for the generation of analytical reports and certificates The system employs two floppy disk drives the left hand drive LHD is generally used for operating sys tem files and the right hand drive RHD is used for analytical programs TAB files data and text files The LHD is identified by name SY and the RHD by name DY1 Floppy disks are easily damaged and the information stored on them cannot be retrieved if the disks are mishandled Back up copies should be made of all system disks every 6 months When not in use disks must be stored in the cases provided To use the computer the system disk is placed in the LHD To activate i e BOOT the computer all three switches at the main computer are switched off and on again Alternatively with all switches on the instruc tion 173000G is typed at the Decwriter It is not possibl
392. oy Riviera Beach Fla 1985 Chan C and Bina S 1989 A Sensitive Automated Method for Determination of Mercury in Geological Materials by Cold Vapor Atomic Absorption Geos tandards Newsletter Vol XIII No 1 Hatch W R 1972 Flameless Atomic Absorption Methods for the Determination of Mercury Canadian Research and Development Nov Dec pp 13 26 Johnson W and Maxwell J Rock and Mineral Analysis Wiley Interscience Publishers 1981 pp 302 303 EA27 3 Mercury N 00000000 Mixing coil Gas liquid separator Flowmeter Proportioning Pump Argon mE Recorder Hg Lamp Automated cold vapour flameless AA system for determination of mercury Figure Hgl EA27 4 Carbonate Carbon DETERMINATION OF CARBONATE CARBON COULOMETRIC METHOD Introduction Carbonate carbon is the main component of total carb oninthe majority of geological samples It is conven tional therefore to report total carbon as as if all the carbon is from carbonate carbon In some samples however carbonate carbon can represent only a small part of the total carbon The remainder of the total carbon is either graphitic organic carbon diamond and or carbide In studies of geological processes it is sometimes necessary to know not only the carbonate carbon or the total carbon content but also the non carbonate carbon in the samples Total carbon can be determined by induct
393. p menus for each function selected Run mode parameters are selected as each run is set up 4 Analysis using the dry sensor A Hiac Royco Pacific Instruments particle size analysis system is used to determine the grain size distribution in the solid fraction 4230 25 Detailed instructions regarding the calibration of the instrument are presented earlier in this section Specific attention is drawn to the following points 4 A sample consisting of about 200 000 par ticles is introduced into the feeder chute such that no more than 500 particles pass the sensor in each second of operation The distribution of particle sizes is registered in 32 channels with preset size intervals 4 2 Care must be taken not to saturate or block the sensor Saturation may result in chains of par ticles being counted as single large particles Too rapid throughput may cause the sensor to become blocked Under no circumstances must particles larger than 25 mesh be intro duced into the sensor 4 3 Each sample should be run in duplicate The average of the data from each analysis is used Grain size Analysis 2 5 Analysis using the wet sensor The wet sensor is used to determine the distribution of 230 mesh particles in a solution containing disper sant As this instrument is equipped with a threshold sensor the smallest particles which it can count are 2 25 microns in size Specific attention is drawn to the following requirements 5
394. pected to be a significant interferent on the Ga analyte line Ka 38 8345 in the vast majority of rock samples Because VSN is used as the highest concentration standard for the calibration of Ga and as it contains 900 ppm Ta the potential interference is accounted for in the program Measuring program parameters are listed below MP3 MASK E c ABS YE CHAN PT PC Rh 20 OEO Ta 20 OEO Ta 40 0 0 40 OEO Ga 20 OEO Analysis of a quartz pellet over the four measured positions Ta Ta Ga and Ga indicated background correction factors 0 9260 Ta 1 1150 Ga Correction for Ta Correction for Ga W i Analysis of a high level tantalum standard Ta1540 indicated an interference contribution at the Ga position of 0 111 Rate correction summary 9 0 0 9260 0 0000 0 0000 0 0000 10 0 Ga 1 1150 TA 0 1111 0 0000 0 0000 Link Program 3 LP3 LPNR 3 NRCH 2 CPNR 3 MODLST 0 MRBR 0 LLNR 0 OPTION 0 INT1 RH ELEMENT Ga RC 9 10 INTR RH The ratioing to the Compton line gave a good mass absorption correction for the Ga line but not for the Ta line EA16 7 Traces XRF Calibration factors were determined using the standards listed below Expected and calculated values obtained in the original calibration are listed below Calibration coefficient and alpha correction values Ta on Ga and Ga on Ta are stored in CP3 GALLIUM Literature Observed ppm ppm NIM S 11 96 SY3 26 29 MAN 59 51 400 401 VSN
395. pectrophotometry and the Argon Hydrogen Flame Analyst Vol 100 pp 300 306 Thompson K C 1974 Atomic Absorption Studies on the Determination of Antimony Arsenic Bismuth Germanium Lead Selenium Tellurium and Tin by Utilizing the Generation of Covalent Hydrides Analyst Vol 99 pp 595 601 A25 5 As Sb Bi Flow Rt Argon Mixing Coil 00070 Mixing Coil Gas Liquid Separator Proportioning Pump Waste Recorder Light Heated Quartz Tube m1 mi 3 90 0 32 1 20 1 20 2 50 3 90 3 90 AutoAnalyzer AAS Flow System for Determination of Antimony Figure 61 A25 6 As Sb Bi 23200 xetdues ET Tn Subt lt u u SVM p 2 4 STOR 17a prnbrI seo Wn m 35 sms ju uobiv A25 7 AutoAnalyzer AAS Flow System for Determination of Arsenic Figure Asl As Sb Bi Gas Liquid Separator t Heated Quartz Tube RUPEE ed Recorder Mixing Coil Mixing Coil AAS Flow System for Determination of Bismuth AutoAnalyzer Figure Bil A25 8 DETERMINATION OF SELENIUM Selenium HYDRIDE AAS AUTOMATED FLOW INJECTION ANALYSIS Introduction In igneous rocks selenium follows sulphur very close ly Therefore selenium is usually present in dete
396. pellet is removed will generally suffice Methanol should be used on the wipe to give a more thorough cleaning The surface in contact with the rock powder must be treated with care It can become pitted and must then be polished by gently rubbing the surface with a fine abrasive mois tened with methanol Application and release of pressure on the die press should be even and slow The die must be placed centrally and must be level Failure to do so can result in uneven loading and mechanical failure 2 Nondestructive Analysis The use of the Philips PW1400 X ray Fluorescence Spectrometer System is described in the Section Majors XRF page EA6 1 3 Calculation of Final Results All necessary calculations are performed automat ically by the system computer EA16 2 uality Control It is important to distinguish between short term batch precision and long term multi year precision Short term precision on jobs and daily assays is monitored via duplicate analyses of 10 of all samples submitted These duplicates are subjected to identical preparation and analytical procedures International reference materials IRM are used to monitor short term precision and accuracy One IRM similar in composition to the sample group being analysed is inserted into group of six samples for both jobs and assays These replicate and IRM data are assessed before the data for geological material are released The Ontario Geological Su
397. per ature of the suspension and the specific gravity of the soil particles Refer to Table GSA2 Distance from the surface of the sus pension to the level at which the density of the suspension is meas ured cm Refer to Table GSA3 Interval of time from beginning of sedimentation to the taking of the reading min Grain size Analysis 1 The results are presented graphically by plotting the diameters of the particles on a horizontal logarithmic scale and the cumulative percentage smaller than a given size on the vertical axis Figure GSA1 The final report should include 1 The maximum particle size 2 The percentage passing each sieve 3 A description of the sand and gravel shape and hardness 4 Specific gravity 5 Any problems in dispersing the 1000 micron frac tion Quality control Analysis of the in house Geoscience Laboratories soil standard should accompany each job Hydrometry should be performed on a 50 g sample of the standard which can be reused The gradation curve for this material is shown in Figure GSA 1 based on data presented in Table GSAS and should be reproduced with a precision of 5 or better MS4 3 17494 yL TABLE GSA2 Temp C 2 45 16 0 01531 17 0 01511 18 0 01492 19 0 01474 20 0 01456 21 0 01438 22 0 01421 23 0 01404 24 0 01388 25 0 01372 26 0 01357 27 001342 28 0 01327 29 0 01312 30 0 01298 MS4 4 VALUES OF K FOR USE IN FORMULA FOR COMPUTING DIAM
398. phur 748 600 Sys tem including A Determinator Model 770 200 B Induction Fumace Model 768 100 C EB 25 Electronic Balance D AWC automatic weight compensation control box cylinder of oxygen with 2 stage regulator 2500 35 psi crucibles including re usable crucible covers tray crucible tongs quartz combustion tube dust traps dust filter 10 micron mesh anhydrone tube glass wool micro fibre filter tubes Reagents vanadium pentoxide ironchips tin pellets ascarite NaOH on asbestos base anhydrone anhydrous Mg C1O4 Procedures 1 Instrument Settings 1 1 Selectthe following settings for the operation of the CS 46 System Power On Gas On Pump On Loop flow 7 5 LPM Automatic manual Auto mode Datatransmit Inhibit Inhibit Function select Operate Weight compensator 1000 High carbon blank Do not adjust Low carbon blank Do not adjust High carbon calibrate Do not adjust EA13 1 Carbon Sulphur Low carbon calibrate Do not adjust Sulphur blank Do not adjust Sulphur calibrate Do not adjust Identification code Do not adjust Warm up period 3 hours minimum Range switch Do not adjust 1 2 Select the following settings for the operation of the CS 46 Induction Furnace Filament voltage On glow white High voltage On glow green Oxygen pressure 35 psi 1 3 Select the following settings for the operation of the CS 46 Balance AWC Control Box Power balance On Aut
399. ple solution is now 3 6N 3096 v v 3 7 Prepare a reagent blank simultaneously EA26 2 3 8 Decant a portion of the solution to a sample cup for subsequent AAS determination 4 Measurement of Se concentration Instrument parameters Atomic absorption spectrometer Wavelength 196 0 nm Lamp current 8 Slit width 300 u Damping C Maximum Expansion 6 Flow injection module Sample time Washing time 30 sec 40 sec Variable transformer Dial S0 set to produce 850 20 C in the atomizer Recorder Span 10mV Chart speed 1 cm min Argon Flow rate 300 ml min Set up the hydride generation equipment and connect the tubing that leads to and from the injection valve of the flow injection module according to the layout shown in Figure Sel Mount the quartz tube on the burner with its side arm connected to the hydride generator with tygon tubing Align the quartz tube with the light beam to allow maximum radiation to reach the detector Switch on the preset variable trans former to provide the desired temperature in the atomizer Turn on the proportioning pump with all the reagent tubes dipped in water Introduce the argon immediately with its flow rate regulated at 300 ml min Tum on the flow injection module which is interfaced with the sampler The motions of the injection valve and the sample probe are synchronized Set the sam pling time to 30 sec and the washing time for 40 sec on the flow injection module
400. pm Zn Linearity drops off sharply inthis range Attempts to calibrate with standards 3 ppm require excessive curve correction and cause the calibration to be unstable ANALYTICAL CAPABILITIES Determination Limit ppm 10 Precision at the 9596 confidence limit 26 at 10X determination limit 100 ppm is 10 ppm absolute Traces AA Barium Ba STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm stock Ba solution to prepare 1 0 2 0 4 0 and 8 0 ppm work ing standards Add 50 ml of 6000 ppm La K solu tion for every 100 ml of working standard prepared 1 ml 3000 ppm La K INSTRUMENT PARAMETERS Lamp Current ma 10 Wavelength nm 553 6 Spectral Band Pass nm 1 0 AAS 100 Background Correction OFF Flame Description Nitrous oxide acetylene Fuel lean small red cone WORKING CONDITIONS Use a strip recorder to trace absorbance readings For Varian Model 9176 set chart speed at 1 cm min mV FS at 5 1 ppm Ba signal for 3 Working range 1 0 to 2 0 ppm 5mV FS 2 0 to 4 0 ppm 10 mV FS 4 0 to 8 0 ppm 20 mV FS INTERFERENCES Ionization in the nitrous oxide acetylene flame is sup pressed with the addition of to samples standards and blanks Stable compound interference from phosphate sili cate aluminate etc is minimized in a nitrous oxide acetylene flame and or by addition of NOTES 1 In the region of 553 6 nm strong emissions from Ba and the nitrous oxide acety
401. precipitate and determined by AA after fusing with LiBO in a platinum crucible EA8 3 Majors Classical 3 3 Silica ignition of precipitate 3 3 1 Carefully fold the papers in the funnels with platinum tipped forceps and transfer them to the original platinum crucible 3 3 2 Wipeoutthe insides of the funnels with a piece of filter paper and add it to the crucible 3 3 3 Place the crucible with the cover not quite in place using a clean fused silica small tray in a cold electric muffle furnace and burn off the paper by allowing the temperature to rise slow ly 3 3 4 Ignite the residue at 1000 C for 30 minutes the full heat of a Meker burner may be used but the furnace is preferred 3 3 5 Coolthe covered crucible in a desiccator for 30 minutes and weigh it 3 3 6 Return the covered crucible to the muffle fur nace for 20 minutes cool for 30 minutes in a desiccator and again weigh it 3 3 7 Continue to ignite for 20 minutes periods until two subsequent weights differ by no more than 0 0002 g The final weight is that of the impure silica 3 4 Silica Treatment with HF to determine impurities 3 4 1 Cautiously moisten the residue with ap proximately 1 ml of distilled water and add 6 drops of dilute H SO 1 1 3 4 2 Quickly pour 10 ml of HF 48 into the crucible and replace the cover 3 4 8 Allow the crucible to stand for 1 or 2 minutes to permit the initial reaction to take place then
402. preferred orientation which may enhance one of its lines A detection limit of 196 is assumed by most workers Klug and Alexander 1971 Productivity Eight to ten samples can be run and indexed in a day Bibliography Jenkins R amp de Vries J L 1972 An introduction to X ray powder diffractometry Philips 41 pages MS10 3 AKD Klug H P amp Alexander L E X ray diffraction pro cedures for polycrystalline and amorphous materials Wiley New York 1974 716 pages Starkey H C Blackmon P D amp Hauff P L 1984 The routine mineralogical analysis of clay bearing samples USGS Bulletin 1563 MS 10 4 Clay XRD X RAY DIFFRACTION IDENTIFICATION Introduction Clay minerals by definition occur as particle less than 2 insize Their identification poses special problems because of their small particle size Over the last four decades clay mineralogists have developed a variety of techniques for clay mineral identification of which XRD has been the most important by far A large number of pre treatments have become available for positively identifying clays but only two of these are routinely used glycolation and heating The prepara tion of clay samples is also different as the clay size fraction has to be separated out In the Geoscience Laboratories the preparation forms part of the grain size analysis procedure which is usually requested at the same time Refer to page MS4 1 Method The method
403. r The Prep Station Option is selected through the MODE key 7 ENTER Select 2 Autosampler with diluter Tumon the Sample Changer and Diluter Press 1 Prime to prime the syringe and fill the rinse station The CRT will display if AA is in the concen tration mode options for Run samples Calibrate with autosampler Standard addition To exit MO Uu Calibration 2 ENTER Change to read 0 0 mls matrix modifier Bulk AZ amp AC BULK VOL 5 0 mls times 0 This allows you to prepare large volumes of auto cal solutions You are given the option of having as many times the previously selected Final Volume in this case 5 0 mls as desired max 45 mls prepared in the AZ and AC vessels Enter 0 to bypass EA3 3 Grahite Furnace Select 1 YES for rinse between samples Select 3 Both for dual channel operation You are now ready to enter the concentration of the standards through the keyboard NOTE STD C is the autocal standard and should be midrange 0 100 ppm STD Z must be zero NOTE The highest standard concentration used in channel A is used by the microcomputer to calculate the concentration of the stock analyte which you must prepare and place in the STOCK vessel Key in the concentrations for each standard in channel A When the desired number of standards have been entered key STD Enter the appropriate concentration for STD C in channel B 0 100 ppm NOTE Enter concentration o
404. r and add a small amount of HCl by heating until it is dissolved 3 14 Total Fe Transfer the solution to the original solution in the 250 ml beaker by washing the Vycor crucible a few times with small portions of distilled water 4 Reduction with stannous chloride 4 1 4 2 4 3 4 4 4 5 4 6 Heat to boiling on a hot plate the complete solution of the sample having a volume of about 50 ml or less Add stannous chloride drop by drop until the yellow Fe colour disappears Add one two drops in excess Cover the reduced solution in the beaker with a watch glass and cool by placing in a tray having cold water Add rapidly 10 ml of 5 HgCl measured in a graduated cylinder A small quantity of white precipitate should appear after 2 to 3 minutes If no precipitate or if the precipitate is grey the sample should be discarded 5 Titration using KMnO 0 1N solution 5 1 5 2 5 3 5 4 3 5 After 2 or 3 minutes transfer the reduced solution quantitatively to a 600 ml beaker containing 25 ml of Zimmerman Reinhardt reagent and 300 ml of distilled water Titrate immediately with KMnO to the first faint pink end point that persists for 15 seconds Do not titrate rapidly at any time Two blanks should be carried through the procedure Correct the volume of KMnO for the blank titration 6 Calculation of the results Fe mgFe mlof KMnO ml for sample mi
405. r coarse grained jaw crushed rock to improve mineral liberation for mineral separation procedures Reagents Acetone Quartzite Procedures 1 Samples are collected from the sample reception area along with a series of labels and a copy of the job sheet Any special instructions accompanying samples should be clarified with the sample recep tion technician 2 Labels are affixed to containers used to store crushed rock and final pulp The sample prepara tion technician assigns a laboratory number in addition to the sample number which determines the sequence in which the samples are ground 3 Hand samples of the rocks are retained in the original sample bags 4 The remainder of the samples are placed in pre viously cleaned containers in ascending order of sample number Any materials affixed to the samples including tape enamel lichen and paint are removed NOTE If the samples are weathered or altered the technician should inform the sample reception technician who will contact the geologist to ascertain whether the weathered material should be removed It is up to the geologist to remove weathered surfaces and other markings 5 Wetsamples are dried in a hot air drier 6 Specific gravity is determined refer to the method of Determining Specific Gravity on page M12 1 7 Theexhaust fan is switched on and the gate to the jaw crusher is opened The jaw crusher is cleaned using compressed air and a wire bru
406. race Interferent Trace Analyte Given the relative concentration levels of most major and trace elements in geological samples we are generally only interested in the interference of trace elements by major elements To a limited extent we are also concerned with Trace Trace interferences where the coefficient is very high It is important however to evaluate all the interferen ces critically for any given matrix type The samples arriving at the Laboratories are varied and complex What may be acceptable for a relatively barren silicate rock may not be acceptable for an ore or a mineral Each case must be examined and where necessary additional interference corrections used The use of concentration ratios or PDL criteria become very im portant A complete list of interference coefficients is on file EA18 13 Traces ICP OES THE TRACE 2 T2 PACKAGE INDUCTIVELY COUPLED PLASMA OPTICAL EMISSION SPECTROSCOPY Introduction Given the extensive analytical potential and flexibility of ICP OES a wide variety of elements can be deter mined using this instrument At the Geoscience Laboratories we have grouped many geologically im portant elements into the Trace 2 package Usually these elements are at the ppm to ppblevels but in some samples from specific geological environments they can be much higher Geologists use trace elements to monitor the genesis of rocks and evaluate process that affect rocks after formation E
407. ratioing would be calculated is entered following the RC number As soon as the number of entries is equal to the NRCH defined previously the system retums to the cursor EA6 25 Majors XRF Calibration Major elements are calibrated using a series of certified reference materials CRM s whose element concentra tion values cover an adequate range for the rock type being considered i e silicate or carbonate rock A regression file is prepared which contains the concentrations and observed intensities for the series The following example illustrates the steps required The measurement program is assumed to be MP 1 Acquiring the Intensities The following commands are made on the assumption that the appropriate measurement and link programs are available along with the RC correction set SPR 1 This command start prepare regression instructs the system to run samples and to store the data in a regression file FILENAME MAJORS Regression file to be created MAJORS ROI SAMPOS This command is common to all instructions operating the spectrometer It asks the operator to identify the turret positions for the SRM s The response is given as the turret numbers separated by spaces in order to introduce sample SRM identifiers the response is followed by an 12341 The sample holder turret then puts 1 into the loading position and opens the port The system prints SAMPLE 1 and awaits the entry of the sample name T
408. rbon has disappeared Never heat strongly while carbon is still present The crucible is kept only partially covered to allow entrance of air During final heating the crucible is almost fully covered 6 Hot platinum ware should always be handled with platinum tipped tongs Before picking up crucibles etc with tongs be sure that the tips of the latter are clean 6 Most stains in platinum can be removed by fusion with little potassium pyrosulphate K5S 0 After cooling the pyrosulphate is dissolved in hot water 6 2 Never allow the blue cone of a flame to touch the platinum crucible being heated To do so causes formation of platinum carbide which will even tually ruin the crucible 6 3 Platinum ware should be kept well bumished with fine sea sand This is important for crucibles which are subjected to long ignitions Bibliography Outline of methods for the Chemical Analysis of Rocks and Minerals Department of Mineralogy University of Toronto Maxwell J A Rock and Mineral Analysis Wiley Interscience Publishers 1968 Potts J P A Handbook of Silicate Rock Analysis Blackie and Sons Limited Glassglow 1987 Titanium DETERMINATION OF TITANIUM AS TiO Introduction Titanium is recognised as one of the most universally distributed elements and the tenth most abundant in the crust of the earth It is present in all igneous metamorphic or sedimen tary rocks of a more or less siliceous ch
409. rcial distribution of the Content the reproduction of multiple copies of the Content for any purpose whether or not commercial use of the Content in commercial publications and the creation of value added products using the Content Contact FOR FURTHER INFORMATION ON PLEASE CONTACT TELEPHONE BY E MAIL The Reproduction of MNDM Publication Local 705 670 5691 Pubsal d Content Services Toll Free 1 888 415 9845 ext Pubsales ndm gov on ca 5691 inside Canada United States The Purchase of MNDM Publication Local 705 670 5691 Pubsal d MNDM Publications Sales Toll Free 1 888 415 9845 ext Pubsales ndm gov on ca 5691 inside Canada United States Crown Copyright Queen s Printer Local 416 326 2678 Copyright gov on ca Toll Free 1 800 668 9938 inside Canada United States LES CONDITIONS CI DESSOUS R GISSENT L UTILISATION DU PR SENT DOCUMENT Votre utilisation de ce document de la Commission g ologique de l Ontario le contenu est r gie par les conditions d crites sur cette page conditions d utilisation En t l chargeant ce contenu vous I utilisateur signifiez que vous avez accept d tre li par les pr sentes conditions d utilisation Contenu Ce contenu est offert en l tat comme service public par le minist re du D veloppement du Nord et des Mines MDNM de la province de l Ontario Les recommandations et les opinions exprim es dans le contenu sont
410. re calculated by the instru ment using the observed instrument response and the sample weight which is determined by a balance linked to the instrument This method determines the total carbon content of a sample as and does not distinguish between carbonate carbon organic or graphitic carbon sour ces Noncarbonate graphite carbon exists in negli gible quantities in most rock samples For this reason is generally considered equal to total carbon It is convenient to consider this assumption valid since LECO determinations are substantially faster than other methods oil displacement gravimetric volumetric carbotrane etc In cases where graphitic carbon is expected to be significant both total LECO and carbonate carbon coulometric Page EA28 1 can be determined and graphitic carbon calculated by difference Diamond is rarely encountered Safety advisory 1 Vanadium pentoxide and magnesium perchlorate can cause serious damage to the skin Exercise caution and wear plastic gloves when handling these materials 2 The induction furnace generates extreme heat Al ways handle crucibles with tongs Method The method consists of the following techniques 1 Conversion and separation of the analytes by com bustion of the sample 2 Detection of the analytes by an infrared detector 3 Calculation of results by reference to standards of known composition Apparatus LECO CS 46 Carbon and Sul
411. re consists of two parts 1 Setting up the run i e entering sample id s dilu tion factors etc 2 Running the samples EA19 9 traces ICE M3 Setting up the run 5 1 1 5 1 2 5 1 11 5 1 12 5 1 13 Confirm that the ECL Command display is onthe screen If not press Gn2 until the display no longer changes and then press B3 Enter QUANT R The cursor can be moved to the various fields by using R Type the name of the appropriate parameter set followed by NOTE The Calibration Field must ALWAYS show STD If it doesn t then change it to the correct value Enter R twice Enter a run number followed by R Enter a run description followed by R Enter n R twice Enter s R Press G1 to get to the Sample Entry screen Enter sample identification and description usually the OGS job number Use R to select fields Press G1 to store the sample information Continue entering sample information and pressing G1 until all samples identifiers have been entered When finished press to get back to the first screen of QUANT 6 Analysing the Run 6 1 1 Use R to move the cursor to the Run Mode field and enter a R to indicate that the autosampler is to be used Place the Elan Apple System Disk in the left hand drive Place the Intensity Data Disk appropriate to the analysis to be performed in the right hand drive Activate the monitor front top rig
412. re obtained commercially or can be produced in house Shelly 1975 3 Determination of birefringence The birefringence or partial birefringence of a mineral section is determined in thin section by observing interference colours in crossed polarised light with the diaphragm below the stage open and using low power objectives The Michel Levy colour chart presents the relationship of birefringence to the thickness of the section horizontal lines and interference colour ver tical lines Figure OM1 illustrates how the chart is read For example a mineral with colour A and thick ness B has a birefringence or partial birefringence of C To perform this determination several grains of a mineral in a thin section are cut parallel to different crystallographic directions and hence intersect the indicatrix in different orientations The interference colors will vary from black in sections cut parallel to the circular section to amaximum for those cut parallel to and or X and Z The grains with the highest interference colors will therefore be diagnostic of the birefringence Preferred orientation in layered or banded rocks often introduces a bias in the section and caution is required in the interpretation of the inter ference color Interference colours are normally split into orders cor responding to the amount by which two rays are out of phase The simplest method of determining the order of the colour is to look at the ed
413. re x y available Na2O and 2y available SiO2 P If silica remains convert nepheline A to albite orthoclase if the available SiO is not sufficient to convert all the nepheline then distribute between x molecules albite or thoclase and y molecules nepheline given by 4y available Na O in A and 6x 8y available SiO but maintain Na O K O 3 1 in nepheline add any or thoclase formed to N and albite to O Q Any residual SiO is calculated as quartz 5 Determine the percentage weights of the norma tive minerals by multiplying the molecular propor Alknorm tions of the minerals in 3 and 4 by the appropriate molecular weight Bibliography Le Bas M J A Norm for Feldspathoidal and Melilitic Igneous Rocks Journal of Geology Vol 81 1973 pp 89 96 MS16 3 Protocols PROTOCOLS FOR SAMPLE DIGESTION AND ANALYTICAL DETERMINATION IN THE ELEMENTAL ANALYSIS SUBSECTION Introduction Samples received for analysis in the Geoscience Laboratories are classified 1 under assigned job numbers or 2 as assay samples Jobs comprise up to 50 samples and can require extensive analytical work including up to 70 elemental determinations for each sample Priorities for these jobs are assigned by the Chief in consultation with the client geologist Assay samples require a faster tumaround time and can require as little as one elemental determination clients include the private sector and
414. read the MSDS sheet on hydrochloric acid and review all safety procedures required for this chemical The 1 1 HCI should be prepared in a fume hood to avoid inhaling acid fumes Method The method consists of the following techniques 1 Sample decomposition by attack 2 Measurement of CO gas evolved 3 Calculation of the results based on an accepted formula Apparatus Chittick gasometric apparatus Fig Ch1 which consists of the following components Decomposition flask 250 mi Graduated 20 ml pipette with stopcock at the base Stopcock Gas measuring tube Levelling bulb Magnetic stirrer and stirring bar 4 cm in length MMO vw Reagents Hydrochloric acid 1 1 Methyl orange indicator Displacement solution Procedures 1 Reagent preparation 1 1 1 1 solution Mix 500 ml of con centrated HCl with 500 ml of distilled water 1 2 Methyl orange indicator Dissolve 0 05 g methyl orange in distilled water and dilute to 100 ml with distilled water 1 3 1 Displacement solution Dissolve 100 g NaCl in 350 ml distilled water 1 3 2 Add 1 g NaHCO and 2 ml methyl orange indicator and then sufficient HCl to make just acid decided pink Stir until all CO is removed 1 3 3 This solution is used in the gas measuring tube and levelling bulb and seldom needs to be replaced 2 Sample decomposition 2 1 Weigh 1 700 g ofthe 200 mesh sample 0 850 g in ca
415. recision and accuracy of the data generated From compilations of large numbers of QC determinations it is possible to outline the long term analytical capabilities as advertised in the Laboratories Analytical Capabilities Document Determination limits precision and accuracy capabilities should be checked on an ongoing basis in order to assure quality performance in the laboratory Productivity A technician should be able to complete 60 samples per day Additional Notes Some commonly encountered problems and possible solutions are discussed below 1 Problems with analysis of glass fusion beads If the analysis total lies outside the 98 5 101 range it is important that all parameters are checked a Check the job sheet and see if the rock type is unusual Check the agreement between LOI and total volatiles Check for high sulphur See if any trace work has been requested and check trace results for unusually high concentrations b c d e gt f 8 Check the LOI sheet to see if LOI calculations correct Analyze the obverse side of the bead or if neces sary crack and refuse It could be necessary to remake the bead from a new sample of rock pulp If LOI and total volatiles disagree re do C S analysis and if necessary perform another LOI determination If C S and LOI are confirmed then additional volatiles may need to be determined Check the FeO Fe O results If appropr
416. regular basis and the results are compared with in house ac cepted values for this standard Table ATT2 Productivity A technician should be able to complete 40 samples per day for non clay material and 10 samples per day for clay rich soils MS5 1 Atterberg EXAMPLE REPORT FOR STANDARD LIQUID LIMIT SECOND os TRIAL 3 C E 100 rounded value of F Table ATT2 MS5 2 Heavy Liquid Separation SEPARATION OF MINERALS USING HEAVY LIQUIDS Introduction Heavy liquids are used to fractionate mineral phases from each other by differentiating the minerals based on their inherent density Separated minerals may then be weighed and or analyzed by conventional geochemical techniques Mineral separations using heavy liquids require that the density of the liquid is such that the mineral to be separated either sinks or floats in the liquid while the rest of the sample does the opposite Heavy liquids most widely used in the laboratory are shown in Table HLS1 TABLE HLSI HEAVY LIQUIDS Liquid Density g cc at 20 C Bromoform 2 89 Tetrabromoethane 2 964 Methyl iodide 3 325 Sodium polytungstate Adjustable up to 2 9 NOTE The first three chemicals are light sensitive and should be stored in dark coloured con tainers Sodium polytungstate will tend to crystallize if the solution is too concentrated Safety advisory 1 The organic heavy liquids are toxic and should be handled with great c
417. rence 1 Reference 2 10 samples Reference 1 Reference 2 Random dupli cates should be analyzed every 20 samples or at least once for sample batches of less than 20 samples 2 Maintenance 2 1 Anhydrone should be replaced when signs of moisture are evident in glass cylinders 2 2 After 8 hours use the furnace and quartz wool filter should be cleaned by initiating the self clean cycle Cleaning takes about 1 2 hour cf Leco Manual Quick Access 4 p S10 Quality Control Quality is controlled by running reference materials at the beginning of the run and after every 10 samples If the results from these analyses are not within 5 relative of the expected values re standardize Leco manual Quick Access 3 p 28 Analysis of random duplicates is performed at least once during each run The method has been adopted directly from the Leco instrument manual Additional information is avail able in the literature and in Potts The optimum working range is 0 10 to 10 H O The precision 9E RSD over this range is 2 5 3 0 Based on 0 5 g sample weight the determination limit for hydrated and structural water are 0 05 and 0 10 respectively The method should be accurate to within 0 01 or 5 of the observed value whichever is greater The sensitivity of the method is 0 01 Validity of Method Data generated by this method Leco were compared with data produced by an established method Gravimetric Re
418. replaced the acid bottle with distilled water and operating the PRIME until a complete rinse is accomplished Majors XRF THE PHILIPS PW1400 X RAY FLUORESCENCE SPECTROMETER SYSTEM Introduction The Philips PW1400 XRF spectrometer a wavelength dispersive X ray fluorescence spectrometer is used to nondestructively analyze the matrix modified samples The spectrometer consists of a 100 kV generator with current and voltage stabilization The X ray tube is a side window tube various tubes with different target materials are avail able in the laboratory e g rhodium general use chromium molybdenum and tungsten The maximum power rating of system is 3 kW The tube system is cooled via a Haskris water chiller The system offers a choice of analyzing crystals up to six mounted on an assembly Crystal positions are 1 LiF200 default crystal in parameter set 2 1417220 3 PET 4 Ge 5 TIAP 6 LiF420 The system has two detectors a flow counter and a scintillation counter These can be used individually or in tandem The spectrometer is equipped with a microprocessor for control and processing of data There is a four posi tion sample holderin the unit A 72 position automatic sampling device is interfaced to the system The sys tem can be fed both manually and via the sampler The instrument and microprocessor are driven by a Digital Micro PDP Minicomputer with dual disk drive 10 Mbyte Winchester hard disk u
419. residue cool add 6 drops of see Note 4 and 15 ml of distilled water 4 12 Place the beaker on the hotplate heat and evaporate to a volume of 10 ml 4 13 Add 1 ml of 10 ppm Rh Ru standard solution to a 100 ml volumetric flask using a dispenser calibrated to accurately deliver 1 ml 4 14 Transfer the sample solution from the beaker into the 100 ml volumetric flask containing the Ru Re standard and make to volume with 10 nitric acid 4 15 well and transfer a portion of the solution to a 17 x 100 mm polypropylene test tube and cap 4 16 Solution is allocated to ICP MS for measure ment see Note 5 NOTES 1 1000ppmRuandRh solutions are purchased from manufacturers supplving plasma standards t3 clean empty supplier HF dispensing bottle may be used for this purpose 3 Thissecondevaporation to dryness is necessary to remove the last traces of HF Without this step low values for the rare earth elements and thorium will result 4 If the sample contains high iron additional may be added to dissolve the iron oxides 5 Dilution factor for this solution is 500 and con tains 100 ppb Ru and Re used in the internal standardization scheme EA2 5 DAMPE LAlISSOLULLOR 6 Foraccurate work use this acid attack followed by a fusion of any residue using a miniumum of flux combine the two solutions indicate total salt con tent of solution and present solution to AAS ICP OES or ICP
420. ributions i e the analyte signal the background and matrix non spectral interference and spectral interference The latter con tribution is very important in a number of spectro Scopic techniques i e optical emission x ray fluorescence and to a lesser extent mass spectrometry The following discussion of inter ference corrections is centered around the problems observed in ICP OES The concepts however are applicable to all forms of spectral interference It is important to separate spectral interference from other forms of matrix interference Spectral inter ference line overlap results from the interaction of an interfering species with the analytical probe to produce asignal atthe detector This interaction is independent of the analyte identity and is only a result of analytical conditions Non spectral matrix interferences general ly result from a physical or chemical interaction be tween the analyte and the interferent or a physical or chemical interaction between the interferent and the analytical conditions which effectively changes the conditions and results in a different level of interaction between analyte and the probe Thus the matrix ele ments may alter the number of analyte species which are in detectable form e g upsetting the analyte ion atom equilibrium and resulting in signal enhance ment or suppression The matrix components may also cause physical flow problems aerosol formation problems etc If
421. rite Hypersthene Diopside Olivine Hedenbergite Table NORM3 Elemental Weight Equiv Oxide 49 10 16 21 2 87 6 84 5 04 8 90 3 53 2 76 102 101 5 1 5 FeO MgO CaO NaOo 5 5 TiO2 3 59 PO2 5 0 54 S 0 00 MnO 0 05 USED 54555970 Weight Group 102 A1203 K20 A1203 6Si02 Na20 Al203 6Si02 CaO AI203 SiO2 K20 A1203 4Si02 2 25102 K20 AI203 Si0O2 CaO Si0O2 MgO SiO2 102 Na20 Fe203 4Si02 FeO Fe203 Fe203 FeO TiO2 3 CaO P205 CaF2 FeS2 5102 CaMgSi206 2 Mg Fe O SiO2 CaFeSi206 Cation Cation Molecular Proportions x 1000 818 46 0 317 17 9 36 2 0 95 5 3 125 7 0 159 9 0 114 6 4 59 3 3 45 2 5 8 0 5 0 0 11 0 1 3 Ilmentite is formed from Ti and an equal amount of Fe MS 15 2 10 11 12 13 14 15 If CO is included in analysis calcite is formed from CO and an equal amount of Ca if required CO can be included in the program Orthoclase and albite are formed provisionally from K and Na respectively combined in the right proportions with Al and Si If there is an excess of Al over K and Na it is combined with the right proportions of Ca and Si to form Anorthite If there is an excess of Al over the Ca it is calcu lated as Corundum If in 5 there is an excess of Na over Alitis to be combined with an equal amount of Fe and twice as much Si to form Acmite The remaining is assigned to magnetite w
422. rmination Limit The significance of a potential interference can also be evaluated in terms of 1 the determination limit or 2 practical detectionlimit forananalyte Detection limits instrumental are generally based on the noise ob served when a large number of replicate integrations are obtained during a single nebulization and represent instrument stability over a relatively short period of time On the other hand the determination limit a much more realistic estimate of the sensitivity of the method is based on 3 times the standard deviation obtained for replicate determinations of a low level sample and may be degraded further by allowance for matrix effects As emission intensities are found to reproduce within 5 10 RSD from one nebulization to the next or from one day to the next a practical detection limit PDL can be defined as 10 RSD blank background inten sity i e approximately 2 times the error equivalent to a 5 RSD in intensity The determination limit generally used in quoting analytical capabilities and the PDL are often found to be approximately equivalent Since the acceptability criteria for a particular result can be expressed in terms of the determination limit or PDL we must account for matrix corrections which will affect or contribute to the determination limit We can write CA soD Al SA AO CM sol CA sol solution apparent analyte concentration A1 A0 calibration coefficients
423. rminations Measurement Programs Measurement Program for Gallium Measurement Program for Tantalum Measurement Program for Ce La and Nd Measurement Program for Cesium Appendix B Mass Absorption Calculation Program for Apple Ile Mass Absorption Values for Selected Silicates SRM s MA Factors Sr Ka Wavelength XRF Detection Limit Calculation Rate Correction Parameters Appendix C Appendix D Appendix E Appendix F Determination of Trace Elements Co Cu Cr Ni Pb Zn Ba Li Ag Cd Mn Fe Atomic Absorption Spectroscometry Determination of Trace Elements by ICP OES Overview of Trace Element Determination by ICP Optical Emission Spectroscopy The Trace 2 T2 Package Appendix A Generation of T2 Final Reports Aqueous Samples Analysis Package Tentative Spectroscopic Analysis Package TSPA Appendix A Generation of the TSPA Certificates Determinatio of Trace Elements by ICP MS Sample Preparation for the T4 and TS ICP MS Package The Elan 250 Trace 4 T4 Elements Trace 5 T5 Elements Determination of the Rare Earth Elements La Ce Nd Sm Eu Yb Lu Thorium Tantalum Hafnium Uranium and Scandium Instrumental Neutron Activation Analysis Determination of Gold Platinum and Palladium Graphite Furnace Atomic Absorption Spectroscopy Determination of Gold in Natural Waters Solvent Extraction and Electrochemical Atomization Method Determination of Fluoride Automated Colorimetric Method Page Header Section
424. rn off the paper at a low temperature in an electric muffle furnace starting with a cold furnace Heat the crucible at 1000 C for 30 minutes displace the cover slightly at the start to facilitate the escape of carbon dioxide and then cover it tightly then cool for 30 minutes in a desiccator and weigh rapidly Re heat at 1000 C for 15 minutes cool for 30 minutes and weigh as rapidly as possible place 5 4 7 proper weights on the balance in advance of the crucible Continue heating until constant weight is ob tained NOTE When calcium oxalate is ignited it looses CO and CO leaving a residue of CaO which is weighed The oxide should be white in colour but occasionally may be light brown or green because of manganese If the successive separations have been made as described neither of these should be present at this junc ture If a correction for manganese is con sidered necessary the determination may be made by AA on the solution of the ignited oxide A knowledge of the strontium and barium content of the sample will indicate whether or not a correction must be applied to the ignited residue for the presence of these elements 6 1 Determination of MgO 6 1 1 6 1 2 6 1 4 The magnesium determination is made on the filtrate from the calcium filtrations which should be about 400 to 500 ml in a 800 ml beaker To the cold about 10 C combined filtrates add a filtered solution of dibasic ammonium ph
425. roblem has yet to be encountered for Y and the REE although Zr has a substantial reagent blank contamination typically 2 ppm in the rock as does Hf typically 0 05 ppm in the rock These RBLK values for Zr and Hf are established by using the Elan QUANT program and the run protocol 10 HNO RBLK1 10 RBLKA 10 HNO 80 ppb calibration standard Results are calculated manually The average analyte signal measured for the 10 HNO solutions which bracket the RBLK is subtracted from the RBLK solu tion signal A sensitivity factor is calculated from 80 ppb cps where cps is the analyte signal corrected for the 10 HNO signal obtained immediately prior to the 80 ppb calibration solution standard The instrument must have warmed up sufficiently so that signal drift is minimal approximately 3 4 of an hour Traces ICP MS The digestion control standard data for a particular batch is compared against the above values by calculat ing the number of standard deviations the control solution data differ from the mean These calculations are printed at the end of the interim report produced by the Apple II concentration calibration calculation software This interim report is filed along with the original bench sheets for the job The run number associated with the data is also included on the bench sheets The run numbers on a particular data disk are written on the disk label The run numbers on a particular d
426. roducing analytical results in the percent range COBALT Cobaltite CoAsS Skutterudite Co Ni As3 Smaltite Erythrite Co Ni 3 AsOg 2 cobalt bloom an arsenic deficient variety of skutterudite CHROMIUM Chromite FeCr O Cr in rocks and soils is generally present as chromic oxide COPPER Native metal Cu Chalcopyrite CuFeS Bornite CusFeS Cuprite Cu 0 Malachite Cu CO Cu is in most sulphide ores There are 600 Cu minerals NICKEL Braggite Millerite Pentlandite Pyrrhotite Kupfernickel Pt Pd Ni S NiS Fe Ni Ss As mineral Ontario has the world s greatest abundance of nickel LEAD Galena Cerussite Wulfenite Anglesite PbS PbCO PbMoO PbSO Inorganic salts of lead are relatively insoluble ZINC Sphalerite Smithsonite BARIUM Barite Witherite ZnS ZnCO BaSO BaCO Barium in solution is precipitated by sulphate and carbonate ions LITHIUM Spodumene Petalite Amblygonite Hectorite LiAlSiOg Li NaXALSi4O 0 Li Al PO F OH complex silicate can contain up to 1 Li O Li compounds are very soluble MANGANESE Pyrolusite Alabandite Rhodocrosite SILVER Native metal Argentite Acanthite MnO MnS MnCo Ag Ags Ags EA17 1 Traces AA TABLE AASI TRACE ELEMENT CONTENT PPM IN IGNEOUS ROCKS Element Uitrabasic Gabbro Co 100 50 Cr 3000 200 Cu 50 100 Ni 1000 120 Pb 0 3 3 Zn 50 100 Ba 20 200 Li 3 10 Mn 1000 1400 Ag ppb 60 110 Cd Most Ag
427. rongly reducing ores such as sulphides by roasting at 650 C D Reducing agents such as carbon flour and Argol used with strongly oxidizing ores E Desulphurizing agents such as Na CO PbO and KNO help to remove excess sulfur from the charge Fire Assay 2 Method 2 Fire Assay Preconcentration with Determination of Au Pt Pd by GFAAS Procedure 2 1 Weigh 10 g of rock pulp 2 2 the pulp with 120 g of the standard flux refer to conventional fire assay method page MS14 2 2 3 Add one drop of silver nitrate AgNO solu tion to make a bead of about 15 mg 2 4 Mix the pulp and reagents in a crucible 2 5 Place the crucible in preheated furnace at 1025 C and heat for 35 minutes 2 6 The position of each sample in the furnace is noted it is not possible to write on the crucible unless a GRAPHITE pencil is used 2 7 Pour and inspect the crucible for lead loss 2 8 Note theslag colour for possible interferences 2 9 the size and appearance of the lead but ton 2 10 Break the slag and free the lead button 20 25 g 2 11 Cube the button with a hammer 2 12 Place the lead cube on a preheated cupel 950 C and heat in the furnace for ap proximately 30 minutes until the lead is ab sorbed by the cupel in the vented atmosphere 2 13 Remove the silver prill and note any peculiarities 2 14 Pass the bead on to the Chemistry subsection for graphite furnace AA analysis Qu
428. rors which may lock up the AA keyboard always power up the system in the following order 1 Water coolant recirculating pump 2 Argon gas 3 188 4 Graphics printer 5 AA 6 Autosampler if used Instrument controls Front panel of CTF 188 ESC Stops the furnace cycle from continuing The RUN light will go out and the ESC light will stay lit until the furnace cuvette cools below 150 C NEB AIR Initiates operation of the vacuum pump for nebulization when aerosol deposition is used DOOR OPEN Opens the furnace cell door for manual pipetting when furnace is cool Pressing a second time will close door RUN Initiates a furnace cycle When the FASTAC ADM Aerosol Deposition Module is in use the fur nace will continue through the number of heating cycles selected under the MODE Key on the AA CRT To discontinue the process press RUN again and the current cycle will be completed and the remaining cycles will not be initiated Pressing ENTER on the AA keyboard will cancel the remaining cycles Right Panel of Video 22E Most controls are self explanatory The following functions should be noted SIGNAL BACKGROUND selects hollow cathode or D2 arc intensity reading respectively for both energy and current indicators In S H mode signal selects monitoring of the low current pulse while background selects monitoring of the high cur rent pulse on energy and current indicators HOLLOW CATHODE lamp cu
429. rovides full control of the detection parameters e g integration time time between successive integrations number of repli cate integrations It also employs specialized routines for establishing analytical programs EA18 2 6 7 under specific conditions regression analysis for calibration curve generation plotting background correction matrix interference correction entrance slit scans profiles blank subtraction detection limit calculations and data acquisition conversion and retrieval When not used to operate the spectrometer the computer can be used as a general purpose device running programs in FORTRAN BASIC and MACRO languages It can also be used for general file manipulation and text editing Off line programs have been written for report generation and the preparation of TSPA worksheets and cer tificates These programs use the ASCII data files created during spectrometer operation The magnitude of the signal reaching a particular channel detector is dependent on the line inten sity This in turn is dependent on the concentra tion of analyte in the sample as well as instrument conditions such as plasma power rate of sample uptake etc The signal is also dependent on inten sity contributions from other elements present in the sample from direct and partial line overlap continuum emission and background effects In strument software allows the operator to correct for many of these interfer
430. rrent for channel A is controlled from turret for channel B by small diameter knob at B Large diameter knob for A and B controls S H background current RESTART STANDBY will reset the micro computer s program counter to 0000 which can correct certain operational errors Grahite Furnace OPERATE used when entering an analytical pro gram HIGH VOLTAGE A B voltages for A or B sets the photomultiplier Keyboard on Video 22E INT used in the flame mode of spectrometer READ initiates integration for flame analysis RUN key on CTF 188 performs the same function for graphite furnace work STD used with calibration procedures ENTER executes the keyed command This key formats the input and output functions ofthe spectrophotometer The CRT displays VO Recorder Printer Serial Port Time Date Wt Correction Percent Modulation To exit tA WN The following settings should be made after the key is pressed and the above menu is displayed For example to choose Recorder press 1 and Enter Default choices are indicated by an asterisk and only require the enter key to be pressed to proceed Once the settings have been made press I O to retum to the menu and continue Exit the menu by pressing 9 and Enter ENTER Enables the formatting of the recorder output 2 Abs Press enter to choose this default setting Then choose 2 Element bkg from the next men
431. run a sequence of samples for different analytical packages 5 3 Enter SMX this will initiate the analysis EA6 5 Majors XRF DETERMINATION OF MAJOR ELEMENTS M1 M2 M3 X RAY FLUORESCENCE SPECTROSCOPY Introduction X ray fluorescence spectroscopy is used for the deter mination of the ten major elements Si Al Total Fe Mg Ca Na K Ti P and Mn The results of the analyses are reported as percent oxides The Philips PW1400 sequential wavelength dispersive spectrometer performs the determinations using two analytical programs one calibrated for a wide range of silicate rocks M1 and M2 packages in which the samples are presented as fused glass discs containing about 15 rock pulp and the other for a range of carbonate rocks M3 package in which samples are presented as pressed powder pellets In the determination of major elements in silicate rocks M1 and M2 packages the sample is matrix matched by mixing with a heavy absorber lanthanium oxide La 03 A fusion with lithium tetraborate flux is carried out The heavy absorber minimizes the dif ferences in mass absorption MA between the samples For carbonate rocks M3 package samples are prepared as rock powder pellets using a boric acid backing No MA correction is employed in the car bonate rock program Geochemical Importance Geochemistry deals with two main topics the com position of the earth and the chemical processes that control the di
432. rvey carries out many multi year projects The analytical data used in the resulting report may come from rocks collected and submitted for analysis over a period of several years For the geological interpretations to be significant they must be based on a realistic evaluation of the long term precision One of the Laboratories blind duplicate quality con trol programs involves the insertion of one subsample of three in house reference materials a granite a basalt and a syenite in the routine analytical work on a monthly basis The precision data from this program are used to derive the Laboratories advertised analyti cal capabilities The stringency of the test allows us to have confidence that the figures we quote are realistic even when applied to multi year projects The rock powder samples are introduced blind into the routine workflow and are subject to no special procedures as often happens when an analyst is aware that QC samples are being run Productivity A technician should be able to complete 40 samples per day Bibliography Health and Welfare Canada Health Protection Branch Bureau of Radiation and Medical Devices 775 Brook field Rd Ottawa Ontario KIA 1 1 Ontario Ministry of Labor Occupational Health and Safety Division Occupational Health and Safety Act and WHMIS Regulations Abbey S 1983 Studies in Standard Samples of Silicate Rocks and Minerals GSC Paper 83 15 Govind
433. s Most chlorine removed from magmas by hydrothermal derivatives finds its way to the sea where it accumu lates Chloride is determined by an automated colorimetric method using flow injection analysis FIA technique The chemical principle of the method is that chloride reacts with mercuric thiocyanate to form mercuric chloride and liberate thiocyanate which in turn reacts with the ferric ion to form a highly coloured complex that is stable and suitable for colorimetry The absor bance of the coloured complex which is proportional to the concentration of the chloride is measured at 480 nm The chemical reactions involved are as follows Hg SCN 2Cr 3 SCNY 2 SCNY Fe E Fe SCN coloured compiex Safety advisory l The following operations should be performed in a fume hood A Preparation of the 6 and 9 nitric acid solution B Preparation of ferric nitrate solution 2 Lithium metaborate flux should be handled with care Avoid inhalation and contact with the skin In the process of mixing lithium metaborate with the sample stirthe contents gently to avoid the fine powder of flux being stirred up in the air Method The method consists of the following techniques Fusion and sample decomposition 2 Measurement of chloride signal using a Model 1000 300 Colorimeter making use of the flow injection analysis technique 3 Calculation of chloride concentration based on a calibr
434. s When a batch of samples is prepared include one reagent blank and one in house reference material on each hotplate used A bottle Bottle 55 of the in house basalt reference material a basalt collected by P C Lightfoot in 1988 has been characterized for quality control purposes for the following analytes Rb Sr Y Zr Nb Cs the lanthanides except Pm Hf and Ta Since about 60 of the samples listed on the PETROCH database are basalts KIWI is appropriate reference material During the certification of this reference material three people prepared a total of 24 aliquots and the solutions were analyzed once by the procedures outlined in this manual Table MS1 Means and associated standard deviations were calcu lated from these data and the values are used to monitor the digestion step of the T4 and T5 procedures TABLE MS1 DIGESTION CONTROL DATA IN HOUSE REFERENCE BAS ALT 1988 MATERIAL BOTTLE 55 N 24 Element Mean Std Dev ug g Rb 14 374 0 348 Sr 307 3 6 64 Zr 173 84 4 431 Nb 13 6 0 20 Cs 0 229 0 009 Hf 4 578 0 145 Ta 0 823 0 028 Y 25 025 0 662 La 21 342 0 655 Ce 50 273 1 484 Pr 6 104 0 17 Nd 27 247 0 65 Sm 6 105 0 156 Eu 1 873 0 045 Gd 5 658 0 152 Tb 0 838 0 023 Dy 5 037 0 20 Ho 0 994 0 022 Er 2 581 0 090 Tm 0 363 0 014 Yb 2 366 0 072 Lu 0 351 0 015 Reagent blanks from each batch must always be check ed However after three years of using the T4 proce dure a reagent blank RBLK p
435. s R amp de Vries J L 1972 An introduction to X ray powder diffractometry Philips 41 pages Klug H P amp Alexander L E X ray diffraction pro cedures for polycrystalline and amorphous materials Wiley New York 1974 716 pages Starkey H C Blackmon P D amp Hauff P L 1984 The routine mineralogical analysis of clay bearing samples USGS Bulletin 1563 Specific Gravity DETERMINATION OF SPECIFIC GRAVITY Introduction Specific gravity is determined on a routine basis for job samples that have been submitted for whole rock geochemical analysis Specific gravity can also be determined for other rocks and minerals where the geologist or prospector has clearly identified this test Specific gravity isoftenused to confirm whether a rock is felsic intermediate or mafic Mafic rocks will have a higher specific gravity because of the presence of iron and magnesium bearing minerals Safety advisory 1 There is no specific safety advisory for this method Method 1 Weighing ofthe dry sample followed by weighing of the sample when wetted 2 Calculation based on the difference of the two weights Apparatus Top loading balance Bucket of water large enough to handle most samples with suspended mesh basket Reagents No specific reagents are required for this method Procedures 1 Weighing of samples 1 1 Weigh dry sample on top loading balance to at least one decimal place 12
436. s use properly designed carts to move the cylinders use appropriate footwear etc Method The method consists of the following techniques 1 Acid digestion of the rock sample see sample preparation page EA 19 1 2 Determination by ICP MS 3 Calculation of final results using a an internal standard or b from external calibration data Apparatus Inductively coupled plasma source mass spectrometer Perkin Elmer Sciex ELAN 250 Ultra violet shield Microcomputer Apple IIe with dual floppy disk drives and Epson FX printer Reagents Purified Argon gas Distilled deionized water Single element 1000 ppm stock solutions of Y La Ce Nd Pr Sm Eu Gd Dy Yb Ru and Re obtained from Spex Industries Metuchen NJ Procedures 1 Reagent and Standard Preparation 1 1 1 200 ml of 1000 ppm single element stock solutions of Tb Ho Er Tm and Lu prepared by dissolving the appropriate amount of rare earth oxide powder obtained from Alpha Products Danvers MA in about 2 ml of concentrated HNO and to 10 drops of con centrated For all serial dilution operations described below use 10 HNO v v for the diluent 1 2 200 ml of a 100 ppm multielement standard called REEA containing Y La Pr Nd Sm 1 3 1 4 1 5 1 6 L5 1 8 1 9 1 10 Eu and Yb prepared by serial dilution of the 1000 ppm single element standards 200 ml of a 100 ppm multielement standard
437. s advanced simultaneously as the counter increments the total number of points counted for that particular phase After counting at least 2000 points for a fine grained sample the modal composition of the sample is deter mined 7 The reflected light microscope A variety of properties can be studied in reflected light but these are generally qualitative in character and MS9 3 Wp eeu ee rarely provide unequivocal identification of a mineral phase Qualitative optical properties are made with either the polarizer inserted and the analyzer out or with both polarizer and analyzer inserted Observations are made in air or with oil immersion objectives Colour reflectance birefringence and reflection pleochroism are observed in plane polarized light anisotropism and intemal reflections are observed under crossed polars 8 Reflectance The amount of light incident on a polished surface of a particular mineral depends on its reflectance Both colour and degree of polishing can produce an anomalous amount of reflection Although the eye cannot measure reflectance directly it is possible to arrange minerals in order of reflectance 9 Bireflectance and Reflection Pleochroism Cubic minerals remain unchanged in reflectance and colour on rotation of the stage whatever the orientation of the grains Basal sections of hexagonal and tetragonal crystals will also appear the same as cubic minerals 10
438. s are not energized replace relay K1 Check that the yellow relay below K1 is seated properly This yellow relay controls the valves between the mechanical pump and the mass spectrometer chamber Improperly seated this relay could leave one of the valves open and the mass spectrometer will not get out of stage 1 pumpdown IMPORTANT Turn on the interface and load coil water supply located at the sink beside the distilled deionized water still in the ICP lab far right tap Ensure that the torch stand has been moved away from the interface plate and is resting against the back stop Turn on the argon gas supply and nebulize deionized water plasma gas 16 l min auxil liary 2 2 l min nebulizer gas 1 0 l min and allow the system to flush for 3 4 minutes Plug in the autosampler Tum off the nebulizer gas flow using the needle valve control knob When the nebulizer pressure gauge registers minimum bleed in about 0 05 l min Set the drum capacitor toggle switch on the front upper left corner of the torch box to MANUAL and adjust the drum capacitor reading to 82 using the white buttons located to the left of the toggle switch 1 3 12 1 3 13 1 3 14 After the start up value has reached 82 set the toggle switch to AUTOMATIC Set the RF torch box power pot to zero fully counter clockwise and push the RF ON but ton Rotate the RF torch box power dial in a clock wise direction so that 0 5 kW of forward pow
439. s in rock samples hydro scopic and structural Hydroscopic sorbed water can be driven off by heating the powdered sample at 105 C to constant weight 2 3 hours Hydroscopic water is generally reported as and structural also called crystalline water is reported as H O A Leco RMC 100 water determinatoris used to rapidly determine both hydroscopic and structural crystal line water The sample is weighed and loaded into the instrument at 105 C Free moisture H O is driven from the sample in a stream of nitrogen which is monitored in an infra red cell Water vapour absorbs infra red radiation The instrument collects the signal and converts it to appropriate units The displayed signal is in units of weight percent A source of determinate error associated with the determination of water is that hydrated minerals like talc topaz staurolite cordierite and epidote do not decompose at temperatures below 1200 C Safety advisory Protective gloves should be worn or tongs used to protect hands from hot sample vessels and when using magnesium perchlorate Method The method consists of the following techniques 1 Separation of the water by heating 2 Detection of the water by monitoring the absorp tion of infra red radiation by the H O molecules 3 Calculation of final result H O based on a calibration using standards of known composition Apparatus Leco RMC 100 Moisture Determinator LB 80 El
440. s indicated by 0 00 A blank means that the element was not determined N D none detected or lt less than are not allowed Quality control The determination limits and precision for individually determined major components by AAS are listed below TABLE MAAS2 Oxide Determination Precision MRV Limit at MRV Percent Abs Percent Percent 102 1 0 1 0 30 Al203 0 2 0 4 10 Fe203 0 2 0 4 5 CaO 0 1 0 4 3 MgO 0 1 0 4 3 Precision is the 95 confidence limit 20 For ex ample CaO at the 3 percent level is determined to 40 4 percent absolute MRV Mid range value Silicon Dioxide SiO STANDARD SOLUTIONS Use certified reference materials and pure silica pow der prepared in the same manner as the samples INSTRUMENT PARAMETERS Lamp Current ma 10 Wavelength nm 251 6 Spectral Band Pass nm 0 2 Flame Description Nitrous oxide acetylene Fuel rich red cone 10 15 mm high INTERFERENCES NOTES 1 The burner height position is very important as there is a very narrow region of the flame where Si absorbs 2 Ifsingle beam mode is used allow 30 minutes for lamp warm up 3 Scan samples for concentration range in order to bracket the sample with standards This is neces sary as only a few samples can be run before burner blockage becomes excessive 4 Before turning flame off reduce the fuel control down on the instrument particularly if fuel flow is greater than 100 Majors AA Aluminium O
441. same time the sample probe swings into the sampler reservoir in a synchronized motion with the rotor The solution in the sample line which is now 6 HNO enters port A and exists through port D This flow flushes out the tailings of the sample solution in preparation for a new cycle of sampling 5 Calculation of the results The chloride concentration ug Cl ml in the sample Solution is read with the aid of a calibration curve blank being subtracted Multiplying this value by a factor of 100 15 ml1 0 15 g to obtain the chloride content in rock in ppm Quality Control The optimum working range for this method is 0 5 to 5 0 ug ml in solution equivalent to 50 to 500 ppm in rock The determination limit is 30 ppm The precision expressed at the 95 confidence limit 20 is 10 relative e g 250 ppm 25 ppm The accuracy is comparable to the precision based on data collected from standard reference materials Productivity A technician should be able to complete 15 determina tions per day Chloride Additional notes 1 In order to maintain a minimum blank value a good grade of lithium metaborate such as sup plied by Spex Industries Cat No L170 and nitric acid such as the Baker Analyzed reagent should be used 2 Ifsamples are low in chloride less than 300 ppm production rate can be increased by cutting down the washing time of the FIA system from 90 seconds to 60 seconds 3 At the e
442. se elements background correction factors are obtained from single points e g No correction is made for mass absorbance This region of the spectrum does not lend itself to the method of Feather and Willis background nor is the Compton scatter ratio meaningful If the major element data are available MA corrections may be applied However for most samples MA variations are expected to be minimal and good values should be obtained without correction Interference factors may be calculated and inserted in the RC table The program uses alpha factors exclusively for inter element correction NR BKGR Li CHL2 L2 CHL3 13 CHL4 L4 11 0 Ce 9200 0 0000 0 0000 0 0000 12 0 Nd 1 1105 0 0000 0 0000 0 0000 13 0 La 1 0000 0 0000 0 0000 0 0000 EA16 11 Traces XRF MP13 MASK ay tT ABS YE CHAN PT PC Ce 50 OEO Ce 100 OEO Nd 100 OEO Nd 50 OEO La 50 OEO La 100 OEO LPNR 13 NRCH 3 CPNR 13 MOPDLST 0 MBNR 0 LLNR 0 OPTION 0 ELMNT Ce Nd La RC 11 12 13 Best fit was obtained for Ce and La without alpha corrections Nd uses an alpha correction for Ce Using a 50 second counting time at the background position counting statistics indicated relatively poor detection limits for Ce La and Nd Determination limits were established as 35 35 and 20 ppm respectively EA16 12 Traces XRF Measurement Program for the Determination of Cesium The chromium X ray tube is favoured for th
443. se the sample contains more than 40 percent carbonates and place it in the decom position flask A in Figure CH1 22 Connect the flask to the Chittick apparatus Open the stopcock C and bring the displace ment solution in the measuring tube D to the 20ml mark above the zero by raising or lower ing the levelling bulb E 2 3 The pipette B is filled to the zero mark with 1 1 2 44 Close the stopcock C and lower the levelling bulb somewhat to reduce the pressure within the apparatus EA31 1 3Chitiick 2 5 Open the stopcock of the pipette and let 20 ml of the 1 1 HCl run into the decomposition flask as quickly as possible 2 6 Switch on the magnetic stirrer to secure in timate mixture of the contents At the same time lower the levelling bulb 2 7 During decomposition prevent the liberated CO from escaping through the pipette by keeping the displacement solution in the levell ing bulb at a lower level about an inch lower than that in the gas measuring tube at all times 2 8 After having dispensed 20 ml of 1 1 into the decomposition flask close the stopcock of the pipette 3 Measurement of Evolved CO Gas 3 1 Exactly 30 seconds after the delivery started equalize the levels of the displacement solution in the levelling bulb and the measuring tube and take the first reading of the volume of CO 3 2 Then lower the levelling bulb again until the evolution of CO has
444. sh 8 Observing necessary safety precautions the rock sample is crushed 9 Crushed sample is split in the vented riffler 10 Reject material is retained in a labelled pulp bag 11 100 g of crushed rock are placed in a cleaned ceramic mill along with an appropriate number of grinding balls normally about five 20 mm ortwo 30 mm and three 20 mm balls Two or four mills are bolted onto the turntable of the planetary ball mill the lid is closed and the machine is switched on for a period of upto 15 minutes depending on sample hardness 12 The powder and ceramic balls are removed from the mill and screened through a 170 mesh nylon sieve onto a piece of glazed paper Any material which is 170 is re ground until the entire sample passes a 170 mesh The agate mortar and pestle are used when the sample is too small for re grinding i e lt 2g 13 The rock powder is rolled on the glazed paper and transferred to a labelled bottle Quality Control The mills are cleaned with quartzite and compressed air Under an in house quality control program three samples in selected jobs are ground in duplicate A record is kept of the sequence in which the samples are ground and of the identity number of the container used for each sample If a high grade sample is iden tified during analysis subsequent samples prepared in the same apparatus are be checked for contamination Productivity A technician should be able to c
445. shed doing this and has displayed the prompt requesting a Default Dilution Factor Enter the factor 7 1 8 The program will prompt for any factors that are different from the default Enter these fac tors The program will perform the intensity to concentration calculations No additional input is required until after the final results have been printed 7 1 9 The program will prompt for the number of the instrument QC solution identifiers and their positions in the run Enter the correct information The program will calculate and produce a report summarizing the instrument QC data This information is presented as the difference between the observed and the expected values divided by the standard deviation associated 7 1 10 7 1 11 Traces ICP MS with the expected value If the error is normal ly distributed then 66 of the results should be between O and one standard deviation Less than 0 5 of the results will be greater than 3 standard deviations when there is no determinate error associated with the meas urement If such an occurrence is observed then there is good reason to believe that the measurement is biased A run or data between check samples will be rejected if more than two of the check samples lie outside 3 standard deviations The program will calculate and produce a report summarizing the preparation QC data This information is presented in a manner similar to that produced for the instrum
446. should be adjusted by a factor of 800 500 1 6 to give abetter approximation of the Ba content in the samples near this concentration DO NOT change any values obtained by other techniques 4 A significant discrepancy exists when the adjusted Screen value is higher than the AAS or ICP result by 2066 Significantly lower Screen values com pared with AAS or ICP results are brought to the attention of the XRF personnel The decision sequence for major element determina tion in the elemental analysis subsection is sum marized in Figure PROTI Frotocols Are the number of elements requested 3 or less NO Determine C S If S content is ex ex Dew Determination to be made by appropriate methods including sample decomposition with acids or flux and measurement by AAS Flame photometry Colorimetry Titration REPORT i Check for presence of substances which will damage Pt ware i e As Sb etc by obtaining infor mation from Screen and client NO YES DO NOT fuse in platinum Proceed with fusion Is a fused bead obtained NO Fe content too high gt 50 YES Proceed with XRF measurement Prepare pressed powder pellet and measure with XRF Is SiO2 content carbonate program XRF calibration gt 30 10 30 in this range is not accurate Figure PROT1 Decision sequence for major element determination EA1 4 SAMPLE DISSOLUTION Introduction The
447. silica may form polymeric hydrated silicic acid which does not dissolve 1 3 Fusion for the determination of tin by ICP MS Read notes for procedure 1 1 above before beginning Each batch of samples 15 maximum must include two blanks and one reference material 1 2 1 Weigh 0 100 g of sample into a porcelain crucible 1 2 2 Add 0 300 g of lithium metaborate and mix well with a teflon coated spatula 1 2 3 Transfer quantitatively to a small graphite crucible 35mm high x 25mm diameter and place on a silica tray 1 2 4 Fuse in a muffle furnace for 15 minutes at 1000 C 1 2 5 Transfer the molten mixture red hot into a 50 ml PTFE beaker containing 25 ml of 10 1 2 6 Stir for 20 30 minutes using a teflon coated stirring bar and a magnetic stirrer see Note 1 1 2 7 After dissolution transfer immediately to a 100 ml volumetric flask containing 1 ml of 10 ppm Ru Re standard see Note 2 Sample Dissolution 1 2 8 Transfer a portion of this solution to a 17 x 100 mm polypropylene test tube cap and circulate to ICP MS for the determination of Sn see Note 3 NOTES 1 Itis important that samples should be stirred and made up to volume immediately to prevent the formation of polymeric hydrated silicic acid 2 For preparation of 10 PPM Ru Re see Sample dissolution for the T4 and T5 Analytical Packages Step 4 1 Page 13 3 Dilution factor for solution is 1000 Nitric acid concentration is 10
448. sing the RSX 11M operating system Video terminal with printer for screen dumping and LA100 Decwriter terminal are both used for either primary system operation and or secondary result generation Terminals can be used to access different software routines as long as the same data files are not accessed simultaneously Procedures 1 Turning the system ON 1 1 Confirm that the Haskris Chiller is turned on water mains must be on The On Off switch is flat in the On position and the lights are on 1 2 Confirm that the supply of clean dry air to the hydraulic system of the spectrometer is con nected gauge should read 60 psi 1 3 Confirm that the current and high voltage set tings on the instrument are set to their mini mum values of 20 kV and 10 mA Settings are controlled from the computer and do not need to be adjusted at the instrument 1 4 Confirm that the P10 gas and air are turned on detector gas flow should be at 0 5 and the capacity should be above 1 0 bars NOTE tanks are changed or any major change in P10 gas pressure occurs the gas leak reset button at the side panel must be activated before setting up the instrument 1 5 Depress the switches for the main and high voltage power located on the upper left comer of the PW1400 NOTE If the X ray tube has not been in use for some time the tube should be warmed up slowly according to the instructions accompanying the tube 1 6
449. sis When a particular analyte drift is greater than 3 times the standard deviation of its statistical data restandardization of the system is necessary or the above mentioned operating parameters should be checked 7 Parameter Table Set up 7 1 Enter TB at the JY main menu 7 2 setting new parameters simply hit RETURN atthe next prompt Otherwise enter the Table filename of the routine stored on system or data disk as 7 3 For daily routine T2 and TSPA packages see the additional notes for the parameters that are currently used in this laboratory Details of setting up these parameters are listed in the JY48P software manual ref 12 0 Traces ICP OES 8 Report Generation 8 1 For the T2 package refer to details listed in GENERATION OF T 2 FINAL REPORT page EA18 21 82 For TSPA package refer to details listed in GENERATION OF THE TSPA CERTIFI CATES AND OR WORKSHEETS page EA18 25 NOTE semi quantitative analysis is required to be reported in ppm instead of in percentage use the program JANET in place of WORCER To report results from the calcium and magnesium package water samples run the analysis under CAMG TAB to generate the Ca and Mg concentra tions on the data disk Then use the program WATER SAV to generate the report 9 Digital PDP 11 23 Computer Shutdown 9 1 Exit the JY48P mode by entering EN at the prompt JY48P routine A Dot prompt will appear Remov
450. sities only 9596 of the background correction factor is used in the correction Interference corrections Preliminary correction for interferences are introduced for U on Rb and for Rb on U Factors obtained from running samples with high interferent and negligible analyte are listed under L2 in the RC table above As these L2 factors are the fraction of the total counts of the interferent element which must be subtracted from the total counts of the interfered element without regard to background correction only partial correction is made at this stage of the data reduction Mass Absorption MA correction is made by ratioing all intensities to the Compton line intensity Final correction is made using the alpha influence factors Calibration The standard reference materials used in the calibration include NIML SY3 MicaFe MAN GH and MRGI These represent a variety of silicate matrices and cover a wide range of concentrations of analytes Zr upto 1 1 NIML Y upto 0 07 SY3 Sr upto 0 46 NIML Rb upto 0 36 MAN Th upto 0 099 SY3 U upto 0 066 SY3 Pb upto 0 013 SY3 Nb upto 0 96 NIML The Measurement program in OTHER used for the Trace 3 package is MPS and the parameters are listed below 5 DO ABS YE CHAN PT PC CHAN PT PC Rh 20 OEO Nb 100 OEO Zr 100 OEO Y 100 OEO Y 40 OEO Sr 100 OEO U 100 OEO Rb 100 OEO Th 100 OEO Th 40 OEO Pb 100 OEO Pb 40 OEO EA16 4 Traces XRF This measuremen
451. slits reduces peak intensities and minor peaks will be lost in the background The detector normally used is a propor tional counter The diffracted beam is also passed through a crystal monochromator which allows only Cu Ka radiation to pass thus ensuring a monochromatic beam Safety advisory 1 As X rays are involved film badges must be wom and the working area is restricted to authorized personnel only Although the instrument has been constructed in a manner to ensure there is no X ray leakage a geiger counter should be regularly used to check for this possiblity Note that the shutter should be closed when the operator is changing the removable slits to avoid leakage of X rays from the slot Method X ray powder diffractometry involves the following steps 1 Sample preparation the sample is ground to a fine powder in alcohol and the slurry is smeared onto a glass slide To ensure randomly oriented mounts aback packing technique should be used Prepara tion of clay mineral samples is given in the follow ing section MS10 1 2 The sample is scanned in the diffractometer generally from 5 to 70 20 3 The peaks are located on the chart and the d spac ing calculated 4 The pattern is indexed and the constituent phases are identified 5 Specialtreatments for clay minerals and metamict see below minerals may be used Apparatus Agate mortar and pestle Petrographic glass slides or sample mounts
452. ss than the reporting increment 0 1 and the SRM should be within 89 relative i e MRB 11 6 78 7 96 with within run precision of better than 256 The optimum range for analysis is 0 1 to 10 The minimum readable volume of the titre should be not more than 0 025 ml The determination limit is 0 10 FeO with a 0 5 g aliquot Precision at the 95 confidence level 26 is 0 2 relative at the mid range value of 596 There are a number of sources of determinate error 1 Iron be introduced as a contaminant during the rock crushing operation where steel crushers are used 2 Also significant ferrous iron can be air oxidized while the sample is being ground since the surface exposed to the atmosphere is greatly increased Studies carried out by Fitton and Gill showed that the measured ferrous iron content of a basalt rock dropped from 6 8 to 6 0 after only four minutes of grinding They recommend no more than thirty seconds of grinding for rocks that are to be analyzed for ferrous iron They do not com ment on the effect of incomplete grinding on the accuracy or precision of the method Langmhyr et al have reported difficulties with incom plete sample dissolution Some iron bearing minerals are refractory and even prolonged boiling will not decompose them Tourmaline Staurolite Fe OH Al SiO FeO TiO Magnetite FeO Fe O are examples FeS is particular ly difficult t
453. sted and made to a final volume of 25 ml is the norm for requests for T1 and T2 elements All subsequent dilutions are the responsibility of the personnel performing the final determination Dilution factor 50 Assay samples whose analytes are determined by flame AAS use a 0 500 g portion of sample made to a final volume of 50 ml Dilution factor 100 The T4 package requires a 0 200 g of sample made to a final volume of 100 ml Dilution factor 500 Silver and cadmium digestion requires a 1 000 g sample made to a final volume of 25 ml Dilution factor 25 Less sample may be used and or larger volumes chosen when elements normally considered as trace components are present at ore grade levels These new dilution factors must be flagged for the attention ofthe instrument operator performing the final determination Quality Control 1 ty Instrumental control and stability are monitored by the instrument operator to assure meaningful data acquisition Appropriate solutions are chosen for this purpose In house or certified reference materials and reagent blanks are used with each batch of samples decomposed These are chosen in consultation with the instrument operator and should account for approximately 10 of the samples decom posed Quality control data relating to accuracy and precision determined with these reference materials are kept by the instrument operator and should be available upon request Data Evaluation
454. stribution of the elements in space and time The former is of particular interest to analytical TABLE MXRF 1 chemists concerned with the analysis of geological materials The earth can be divided into zones or shells the core mantle crust hydrosphere and atmosphere The core is approximately 3500 km in radius and is composed of 90 8 Fe 8 6 Ni and 0 6 Co which is the approximate composition of iron meteorites The mantle is about 3000 km thick and is assumed to be composed of mainly peridotite a rock composed main ly of olivine with some pyroxene both silicate minerals containing Fe and Mg The crust is composed of mainly granitic simatic and sialic materials differing in relative proportions in different locations The term simatic comes from silica and magnesia Similarly the term sialic comes from silica and alumina These materials are complex and are not homogeneous Table MXRF 1 summarizes the approximate com positions of four common rock types The relative abundance of the 14 most common ele ments in the crust is O gt Si gt Al gt Fe gt Ca gt Na gt K gt Mg gt Ti gt H gt P gt Mn gt S gt C The standard classes of rocks are igneous sedimen tary and metamorphic As a rough approximation because the last two classes are derived from the first the average composition of the accessible part of the crust can be represented by that of igneous rocks Compositions are given in Percent by Weight Component Perido
455. sure that all areas of the paper are reached lift up the inside flap with Majors Classical 5 3 4 5 3 5 5 3 6 5 3 9 5 4 5 4 1 5 4 2 5 4 3 5 4 4 5 4 5 5 4 6 EA8 8 platinum tipped tongs and wash the area beneath it Finally wash the beaker and paper once with water The final volume should be about 100 to 150 ml Remove and discard the paper and rinse the funnel into the solution once with water Add approximately 0 5 g ammonium oxalate dissolved in a few ml of distilled water to the acid solution add 2 drops of indicator methyl orange 0 02 aqueous solution and heat the solution nearly to boiling Precipitate the calcium as described previously and allow to stand for at least 4 hours or ovemight Filterthrough 12 5 cm Whatman No 40 paper combining the filtrate with that obtained from the first filtration and transferring the precipitate quantitatively to the paper Wash the precipitate and paper 10 times with the cold 0 1 ammonium oxalate solution Reserve the combined filtrates for the sub sequent separation and determination of mag nesium Calcium Ignition of calcium oxalate Place the loosely filter paper in a weighed 25 ml platinum crucible Wipe the inside of funnel near top with a small scrap of ashless paper to remove the small amount of precipitate which usually creep up from the edge of paper Add it to the crucible partly cover it Bu
456. t set power switch to ON function switch to EXT autosampler pipetting unit Auto Adj switch to AUTO up position Op Load switch to OP up position Enter ANA at ANA CHC END Enter CNCODFASBS see JY48P software manual for explanations EA18 17 Traces ICP OES 5 1 5 2 5 3 5 4 5 5 5 6 5 7 Enter XX where XX of samples MAXIMUM of samples is 50 At the prompt X sample name where X sequence of sample number start entering the sample identifiers Refer to the JY48P software manual At the last sample ID entry ensure all of the above have been done before hitting RETURN At this point the pipet of the autosampler will go into the first sample tube and the analysis will begin System Calibration Set check all plasma conditions and resistance settings for the analytes of interest Run the calibration standards blank deionied water blank 10 HNO calibration standards see additional notes In the JY48P mode enter RG for regression routine The computer first asks for a table filename there is no need to answer this question just hit RETURN and then requests a standards filename See JY48P software manual for details Enter INT at the RG mode enter the standard numbers 1 to 20 and the corresponding data filenames when all standard files have been entered and standard prompt is displayed hit RETURN to end intensity entry and the
457. t program is also used for the determination of individual elements in this group given the extent of mutual interference and alpha correction factors The Link program LPS specifies the rate corrections and shows that all analyte channels are ratioed to the Compton scatter peak RH channel listed as internal standard for mass absorption corrections LPNR 5 NRCH 8 CPNR 5 MODLST 0 MBNR 0 LLNR 0 OPTION 0 INT1 RH ELMNT Zr Y Sr U Rb Th Pb Nb RC 1 2 34 567 8 Accepted values Abbey 1983 Govindaraju 1989 of element concentrations in ppm used in the calibrations are listed below Zr Y Sr U Rb Th Pb Nb MicaFe 800 25 5 60 2200 150 13 270 NIM L 11000 25 4600 14 190 65 43 960 GA 150 21 310 4 175 17 30 10 SY3 320 740 306 650 208 990 130 130 MAN 27 1 84 12 3600 1 29 175 MRG 1 105 16 260 1 8 1 10 20 GH 150 70 10 18 390 90 45 85 BEN 270 30 1350 2 4 47 11 4 100 Calibration curves obtained from the DJ De Jongh model are linear Coefficients D E and alpha values are stored in CP 5 and are listed below ELM ND NC D E CEL ALPHA CEL ALPHA Pb 3 0 0 00636 3 77756 Th 3 1 0 00068 3 04205 Rb 9 54918 Rb 3 0 0 00376 1 18923 U 3 1 0 00036 2 93207 Rb 19 07030 Sr 3 0 0 00839 0 91437 Y 3 1 0 02234 1 10890 Rb 28 09171 Nb 3 2 0 00257 0 89649 Zr 30 95473 Th 40 7827 Zr 3 2 0 02175 0 77185 Sr 35 05055 Th 0 84639 Agreement with expected and calculated values is generally good For example in an initial calibration of Zr the followi
458. tages to make the y and Lu signal approximate ly equal generally results in an unacceptable overall loss of signal across the mass region of interest 3 1 11 If the observed intensities are lower than ex pected check the torch position Traces ICP MS 4 Setting Up the Run 4 1 1 Loadthe autosampler according to the follow ing protocol Run Protocol Sample solutions are run with the autosampler in batches using the following scheme ACDBLK 1056 nitric acid INTERFERENCE STANDARDS REEA REEB DRIFTSTD REESTD JUNK CHK 7 10 samples CHK 7 10 samples reagent blank NOTE The sample IDs ACDBLK and BLK must be used CHK is the within run control standard whose values are established against those of an SRM Currently a rock composite solution has been calibrated for REE against BHVO 1 and is used as the CHK solution JUNK is a sample primarily used to minimize memory effects from the drift standards 4 1 2 Position the first sample in the run so that it is in front of the sample sipper 4 1 3 Initiate analysis as described below 5 Performing Analysis Quantitative analysis is performed with the aid of two computers the instrument computer and a microcom puter Apple IIe The Apple computer collects and stores the raw intensities during analysis At the con clusion of the run it processes the data to determine final concentrations The operation of these computers is described below This procedu
459. te results in retardation or compensation in alternate quadrants Minerals with positive are slow whereas minerals with negative are fast Thus as shown in Figure OMA the change in pattern is diagnostic of positive or negative uniaxial minerals In biaxial figures the pattern of retardation and com pensation in relation to the isogyres enables the posi tions of X Y and Z to be determined and the optic sign of the mineral 3 4 Interpretation of figures 3 4 1 Uniaxial cross interference figures Figure OM The mineral is uniaxial or biaxial with 2V close to 0 The optic axis is approximately vertical in the section The positive or negative character can be determined Off centred figures can be used provided the centers can be seen In these circumstances the optic axis may be 20 30 from vertical When the crossed isogyres move out of the field of view there is no guarantee that the figure is not biaxial and therefore these figures should not be used 3 4 1 Biaxial optic axis figures Figure OM2 If the middle of an isogyre remains in the centre of the field of view during rotation of the stage the mineral is biaxial Figure OM2 The degree of curvature of the isogyres enables 2V to be estimated For a 2V of 90 the isogyres remain straight during rotation The cur vature becomes large at 2V less than 20 At 0 the figure resembles a uniaxial cross The positive or negative character can be determ
460. te solution 2 Stannous Chloride solution 30 w v EA27 1 Mercury Hydroxylamine hydrochloride solution 596 w v Mercury standard stock solution 1000 ug ml Hg such as supplied by Baker Chemical Co Mercury standard solutions Mercury working standard solutions Procedures 1 Reagent preparation 1 1 1 2 1 4 1 5 10 Nitric acid v v Prepare 2 liters of solution by diluting 200 ml of concentrated nitric acid with 1 8 liters of distilled water 20 Nitric acid v v for sample dilution pur poses Prepare 2 liters of solution by diluting 400 ml of concentrated nitric acid with 1 6 liters of distilled water Potassium dichromate solution 296 w v Dis solve 4 g of K Cr O in 200 ml of distilled water Stannous chloride solution 30 w v Dis solve 60 g of stannous chloride in 60 ml of concentrated and dilute to 200 ml with distilled water Hydroxylamine hydrochloride solution 5 w v Dissolve 10 g of hydroxylamine hydrochloride in distilled water and make up to 200 ml 2 Standard Hg solution preparation 2 1 2 1 1 2 4 22 Danes EA27 Mercury standard solutions 1 ug ml Hg solution Prepare by serial dilution of the 1000 ug ml Hg stock solution with 20 nitric acid 25 ng ml Hg solution Prepare by serial dilu tion of the 1 g m Hg stock solution with 20 nitric acid Store solutions in a glass container Mercury working standard solutions
461. ted for verification The program then prompts for the new client information as per the procedure in Option 2 and also gives the user the option to print out part or all of the client file ELEFIL ELEFIL creates a DAT on the system disk This file contains all the elemental identifiers associated with the JY48 TSPA analysis The maximum number of elements allowed is 30 At present number of elements used for the certificate or worksheet is 27 including total radioactivity The TSPA data from the JY48P also includes arsenic silver and tin These have to be included even though they are not reported Therefore the total number of elements in the file is 30 EA18 27 Traces ICP OES The program will prompt for a filename to store the element identifiers NOTE The element identifiers must be entered in the same order as they appear in the original JY48 data file Once the required information has been entered the program allows the user to correct the entered information WORCER This program generates the signature ready TSPA certificates and or worksheets It prompts for the names of the client information file created with the INFORM program and the element file name created by the ELEFIL The program will prompt the user to enter the total number of clients and then for each client in turn asks a the record number corresponding to the client s name and address b the date the samples were received c the total number of s
462. tenu des fins commerciales la reproduction de copies multiples du contenu des fins commerciales ou non l utilisation du contenu dans des publications commerciales et la cr ation de produits valeur ajout e l aide du contenu Renseignements POUR PLUS DE oe VEUILLEZ VOUS PAR TELEPHONE PAR COURRIEL RENSEIGNEMENTS SUR ADRESSER A la reproduction du Services de Local 705 670 5691 p contenu publication du MDNM Num ro sans frais 1 888 415 9845 Pubsales ndm gov on ca poste 5691 au Canada et aux Etats Unis l achat des Vente de publications Local 705 670 5691 Pubsal d publications du MDNM du MDNM Num ro sans frais 1 888 415 9845 Pubsales ndm gov on ca poste 5691 au Canada et aux Etats Unis les droits d auteurs de Imprimeur de la Local 416 326 2678 Copyright gov on ca la Couronne Reine Num ro sans frais 1 800 668 9938 au Canada et aux Etats Unis Ministry of Northern Development and Mines Ontario The Analysis of Geological Materials Volume 11 A Manual of Methods Ontario Geological Survey Miscellaneous Paper 149 Staff of the Geoscience Laboratories Ontario Geological Survey 1990 LSOIN 914 2512 ISBN 0 7729 7036 X v 11 ISBN 0 7729 7034 3 set 1990 Qucen s Printer for Ontario Publications of the Ontario Geological Survey and the Ministry of Northern Develop ment and Mines are available from the following sources Orders for publications
463. ters RC rate count corrections The Measurement Program MP The measurement program controls the actual acquisition of counts i e channels to be counted counting time counting mode etc and contains the following information Mask used aperture 1 large 2 small Count mode absolute counts or ratio Channels and count times The Measurement Program is stored in the Parameter Bank and there may be up to 63 such programs in any PB It is therefore important to keep track of program numbers identifiers For example if the majors package were to be assigned to measurement program 1 in DB PB MAJORS then the instructions would be AMP 1 MASK 1 R default 1 ABS S CHAN refers to the name of the channel to be measured This can be either true analyte channel a background or offset Compton line etc PT refers to the counting time in seconds PC refers to the maximum number of counts desired generally this is left to its default value i e no count limit OEO For the MAJORS the program includes counting at all major element channels and the offset positions for Mn Ti P Mg and Na Counting times for elements range between 20 and 40 seconds whereas offset positions are counted for only 10 sec MASK 1 R ABS 0 OEO K 40 0 OEO Fe 20 0 OEO Mn 10 0 OEO entering all channels 0 OEO
464. tes Web ainsi que votre droit d utiliser ou de reproduire leur contenu sont assujettis aux conditions d utilisation propres chacun de ces sites Tout commentaire ou toute question concernant l un de ces sites doivent tre adress s au propri taire du site Droits d auteur Le contenu est prot g par les lois canadiennes et internationales sur la propri t intellectuelle Sauf indication contraire les droits d auteurs appartiennent l imprimeur de la Reine pour l Ontario Nous recommandons de faire paraitre ainsi toute r f rence au contenu nom de famille de l auteur initiales ann e de publication titre du document Commission g ologique de l Ontario s rie et num ro de publication nombre de pages Utilisation et reproduction du contenu Le contenu ne peut tre utilis et reproduit qu en conformit avec les lois sur la propri t intellectuelle applicables L utilisation de courts extraits du contenu des fins non commerciales est autoris condition de faire une mention de source appropri e reconnaissant les droits d auteurs de la Couronne Toute reproduction importante du contenu ou toute utilisation en tout ou en partie du contenu des fins commerciales est interdite sans l autorisation crite pr alable du MDNM Une reproduction jug e importante comprend la reproduction de toute illustration ou figure comme les graphiques les diagrammes les cartes etc L utilisation commerciale comprend la distribution du con
465. tes a concentration file containing T 2 concentration data on the system disk A maximum of 150 samples can be processed at one time The user runs the program JOBFIL to create two files a file containing the sample identifiers and a file containing the geologists names and job numbers A maximum of 150 samples and 10 jobs can be processed at one time The program T2FORM prints out a signature ready T2 form All data are rounded to the nearest 1 ppm rock Any results less than the method determination limit are reported as the minus ofthe determination limit Any results greater than or equal to one percent are reported to the nearest decimal with a P appended to them 1 Insert the system disk for T2 report forms into drive 1 NOTE The T2 Report programs must be run on system disks that have been formatted to maximize disk space Use ONLY these specially formatted disks to run the T2 programs 2 Insert the disk that has the JY DAT files into DY1 drive In this report the symbol denotes user entered filename 3 Check the directory of the system disk The names of the two files DAT and CON that are generated by the T2CON and JOBFIL programs have to be unique Note If necessary delete any unnecessary DAT and CON files to maximize disk space on the system disk The file TTIO DAT should never be deleted 4 Enter R T2CON For details see T2CON 5 Enter R JOBFIL For details see JOBFIL 6 Enter TZFORM For
466. th detectors Peaks may be EA20 2 examined and regions of interest established whilst data acquisition continues uality Control UTB 1 University of Toronto Basalt Standard is used inestablishing a primary calibration Secondary stand ards are used to ensure precision and accuracy are within acceptable limits Refer to NAA2 various external standards are available for this purpose Productivity This technique is not automated and is extremely labour intensive It may take about eight days over a 60 day period to produce data for 50 samples Bibliography Frogatt P unpublished Analyzing for Rare Earth Elements by Neutron Activation at the University of Toronto Slowpoke Reactor Traces NAA TABLE 1 TABLE OF ELEMENTS AND INTERFERENCES PEAKS FOR INAA COUNTING 7 day counts 40 day counts Element Peak Interferences Element Peak Interferences eV eV Ho 80 6 TEMP Ta 67 8 Nd 91 0 Ba 92 3 amp possible Br Tm 84 3 Ta 84 6 Sm 103 2 U Th Eu 122 0 Ba 124 U 106 4 Ce 145 4 Th Mo 140 3 Ba 216 0 Tb 215 6 Lu 208 3 U 209 7 Tb 298 6 Th 2 300 Ba 216 0 Th Q 215 6 Th 311 9 Yb 282 6 Cr 320 1 Tb 298 6 Th 300 poor Hf 482 0 Th 311 9 Cs 795 8 Yb 396 1 Th Ni 810 8 Au 411 8 Tb 879 3 AS 559 1 Sc 889 3 La 815 6 Fe 1099 3 Sc 889 3 Zn 1115 5 Tb Rb 1076 6 Ta 1221 3 Fe 1099 3 Co 1332 5 La 1596 2 Eu 1408 1 Preferred peak for most rocks TABLE NAA2 ANALYTICAL DATA FOR ROCK STANDARDS DETERMINED BY
467. the 95 confidence limit 20 at 10X determination limit 20 ppm is 1 ppm absolute Traces AA Cadmium Cd STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm stock Cd solution to prepare 0 5 1 0 and 2 0 ppm working standards INSTRUMENT PARAMETERS Lamp Current ma 3 5 Wavelength nm 228 8 Spectral Band Pass nm 0 5 Background Correction ON Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Cd solution reads 0 540 absorbance Calibration Set 1 00 ppm to read 1 00 Working range 0 5 to 2 0 ppm INTERFERENCES Background correction is required because of low resonance wavelength ANALYTICAL CAPABILITIES Determination Limit ppm 2 Precision at the 95 confidence level 26 at 10X determination limit 20 ppm is 2 ppm absolute EA17 11 Traces ICP OES OVERVIEW OF TRACE ELEMENT DETERMINATION BY ICP OPTICAL EMISSION SPECTROSCOPY Introduction Inductively coupled plasma optical emission spectros copy ICP OES is employed for the determination of a number of trace elements in geological materials The ICP OES packages offered by the Geoscience Laboratories GLOGS include Aqueous Scan The Geoscience Laboratories is able to accept aqueous samples for analysis on the JY48P ICP Spectrometer No sample preparation is required and simultaneous determination of up to 36 elements is possible The available elements are Sn Mo W B Zn P Pb Co
468. the ener gy meter settles in the 0 2 to 0 5 milliamperes range Select the optimum absorbance range normal ly at 0 08 position Tum on the recorder Set the span at 1 mV and chart speed at 1 cm min Set up the auto analyzer system using the tube manifold as depicted in Figure Hg1 Load the sample cups containing the sample solutions including the standard and blank solutions into the slots of a sample tray held on the automatic sampler 4 6 Tum on the proportioning pump with all the reagent tubes dipped in distilled water 4 7 Tumonthe argon cylinder and introduce argon to the reacting stream with the argon flow rate regulated by the flowmeter at dial setting 30 4 8 Once the system has stabilized insert the reagent tubes into their corresponding solu tions 49 Recstabilizethe system and establish a baseline on the recorder chart 4 10 Switch on the automatic sampler The stand ard sample and blank solutions will then be run sequentially 4 11 Record the absorption signals on a recorder chart 4 12 Measure the peak heights and draw a calibra tion graph Read the concentration of Hg in the sample solution from the calibration graph Subtract the blank value to obtain the net concentration ng Hg ml Calculate the Hg concentration in the rock sample according to the formula 25 mi 0 25 g ng Hg g inrock ng Hg ml x ng Hg ml x 100m g Quality Control The optimum working range is O 1
469. the most reliable method of identification therefore a variety of special techniques have been developed to reliably identify clays Instrumentation The X ray diffractometer consists of a source of radiation a diffractometer and a detection and counting system The most common type of source is an X ray sealed tube system which consists of a heated tungsten filament firing electrons at a copper anode for Cu X rays from which X rays are emitted The electrons are accelerated towards the anode by means of ahigh potential whichis supplied by the high voltage generator Large amounts of heat are generated by this process and water cooling is essential The intensity of the X rays is directly dependant on the current and voltage used which must never exceed the rating for that tube Tube life will be prolonged by use of a voltage and current below the maximum The diffractometer has a specimen holder which rotates at an angle 0 relative to the parallel beam The detection system is on an arm rotating at an angle of 20 Both the incident and diffracted beams are col limated by a series of parallel slits The divergence of the beam is further limited by a divergence slit which is normally 1 a narrower slit of 1 4 is used if low 20 angles are to be used The size of the receiving slit on the detector arm governs the width of the line profile narrow slits will therefore allow better resolution The use of narrow divergence or receiving
470. the separator Sizing is also important while the best grain size to work with will depend on the rock the most common size range used is 100 140 Finer sizes may be used if the proportion of composite mineral grains is unacceptably high Finally a hand magnet is passed over the sample to remove the ferromag netic minerals which can clog the flow of material in the chute unless removed 2 Mineral separation the material is placed in the feed hopper and using an appropriate feed rate is fed onto the vibrating chute The fastest way to proceed is to divide the material by half during MS7 1 Magnetic each pass making sure that the mineral of interest isentirely inone ofthe halves The magnetic range necessary for the separation of that mineral will soon be arrived at At any stage if the volume of material is sufficiently small 50 ml heavy li quids may be used to further concentrate the mineral required The final stages of separation will take place at high side inclinations and changes in the magnetic field between passes will be very small The most important point to remember is that each rock is different and that there are no set procedures to follow trial passes are always necessary to see how a mineral mixture reacts to different settings of the magnetic field feed rate and side slope Apparatus Magnetic separator Binocular microscope Clean paper to cover the working surfaces to prevent c
471. thereby optimizing the accuracy of measurement Safety advisory 1 Reagent preparation and sample extractions are to be done in a fume hood to avoid inhaling and exposure to MIBK vapor and acid fumes 2 Great care should be exercised in pipetting bromine to avoid dripping or spilling of the ob noxious liquid Never pipet by mouth always use a pipette bulb Method The method consists of the following techniques 1 Extraction and preconcentration of the gold 2 Measurement of the gold absorption signal by GFAAS 3 Calculation of the gold concentration based on a calibration curve produced from known standard solutions Apparatus Perkin Elmer Model 603 atomic absorption spectrophotometer equipped with a model 56 chart recorder HGA 500 graphite furnace and programmer with microcomputer controlled power supply AS 1 autosampler Pyrolytically coated graphite tubes Hot plate Glass beakers 400 ml Glass filtering funnels and Whatman No 40 filter paper Glass separatory funnels 125 ml Glass test tubes 10 X 75 mm Reagents Hydrobromic acid HBr 48 Hydrochloric acid HCl 38 Nitric acid HNO3 70 Bromine 0 5 bromine in hydrobromic acid Cleaning solution Methyl isobutyl ketone MIBK 0 1N HBr solution 5 v v solution 1000 ppm Au standard solution gold chloride in distilled water lppm Au in 8 solution 100 ng Au ml in 8
472. tical Mineralogy Elsevier Amsterdam 1975 Optical Minerology BIREFRINGENCE THICKNESS RETARDATION Figure Diagram illustrating how the Michel Levy chart is used MS9 5 WBE ELE FATAL oy lt e M All ve Schemes reversed for ve Optic axis figure of a biaxial ve mineral using a sensitive tint plate or quartz wedge b blue y yellow arrows indicate movement of colour rings when wedge inserted va Ve Distinction of biaxial ve from biaxial ve acute bisectrix interference figures using a sensitive tint plate or quartz wedge b blue y yellow arrows indicate movement of colour rings when wedge inserted Distinction of biaxial ve from biaxial ve acute bisectrix interference figures using a sensitive tint plate or quartz wedge b blue y yellow arrows indicate movement of colour rings when wedge inserted Figure OM2 MS9 6 X RAY POWDER DIFFRACTION XRD Introduction X ray powder diffractometry XRD is a widely used diffraction technique for the precise and rapid iden tification of crystalline materials However complica tions occur when mineral mixtures are used and it is preferable to use monominerallic powder mounts when an unequivocal result is desired The following paragraphs summarise the principles of the technique Inthe X ray diffractometer a collimated beam of Cu X rays other radiations such as Mo Cr Fe amp Co can
473. tion time may be changed next followed by integration delay time usually 0 0 The delay time is the time during which the microprocessor waits until beginning the stage chosen for integration At this stage the Plot vs Time selection menu will appear if the graphics option is included Chose option 2 default to obtain a plot of total absorbance solid line corrected absor bance dotted line and a temperature profile FASTAC option permits adjusting of the fastac delay and deposit times once the option has been selected FASTAC delay is a time period which the sample is allowed to rinse through the spray chamber and then be drawn to waste by vacuum The recommended time delay is 6 seconds but may vary according to capillary length FASTAC deposit is the time period during which the sample is drawn through the nebulizer into the cuvette Higher concentrations require shorter deposit times and vice versa The Furnace Curve portion of the Recall menu acts as a storage for calibration curves which have been previously stored by the operator and placed in this menu Storage capacity is 40 numbered 0 through 39 After typing 6 and pressing ENTER the first 10 curves are depicted on the CRT Further pages can be dis EA3 5 Grahite Furnace played by pressing ENTER The desired calibration curve can be displayed by typing the appropriate num ber 0 to 39 and pressing ENTER Pressing ENTER again will print the curve The Recall menu
474. tions Grain size analysis is widely used in the engineering classifica 0 187 4760 4 76 4 tion of soils It is useful in assessing soil permeability 5 0 157 4000 4 00 and capillarity which are important considerations in 6 0 132 3360 3 36 predicting soil behavior in cold climates 7 0 111 2830 2 83 8 0 0937 2380 2 38 An important use particularily with coarse soils is in 10 0 0787 2000 2 00 designing inverted fillers for dams and levees Grain 12 0 0661 1680 1 68 size analysis is also used in the study of sedimentary 14 0 0555 1410 1 41 rocks as grain size distributions are a function of the 16 0 0469 1190 1 19 processes forming the sediment 18 0 0394 1000 1 00 20 0 0331 840 0 84 Grain size analysis may be performed by either 25 0 0280 710 0 71 30 0 0232 590 0 59 1 conventional sieve hydrometry ASTM D422 35 0 0197 500 0 50 72 technique 40 0 0165 420 0 42 45 0 0138 350 0 35 2 The use of a limited number of sieves a particle 80 0 0070 177 0 177 sizing system and a clay fraction determination by 100 0 0059 149 0 149 hydrometry 120 0 0049 125 0 125 140 0 0041 105 0 105 The latter procedure is not well suited to samples with 170 0 0035 88 0 088 high clay content greater than 25 less than 2mu in 200 0 0029 74 0 074 size 230 0 0024 62 0 062 270 0 0021 53 0 053 Table GSA1 shows the relationship between sieve 325 0 0017 44 0 044 number and particle size 400 0 0015 37 0 037 500 0 0014 31 0 031 Safety advisory 1 When sieving
475. tirring 5 2 3 When lt 1 calcium is present the precipitate may not appear for several minutes and cal cium should not be judged to be absent until the solution has stood for the time recommended NOTE The calcium oxalate precipitated is never pure but contains occluded magnesium oxalate as well as sodium salts Hence after filtering the precipitate is dissolved re precipitated and re filtered NOTE Be careful when heating to avoid bumping especially where there is a heavy precipitate of calcium oxalate 5 2 4 Filter the solution through 12 5 cm Whatman No 40 paper into an 800 ml beaker retaining as much of the precipitate in the original beaker as is possible Wash the precipitate 3 or 4 times by decantation with cold 0 1 am monium oxalate and pourthe washings through the paper NOTE Due to the common ion effect Ca C O is less soluble in weak ammounium oxalate solution than in pure water Wash the paper 3 or 4 times with the am monium oxalate solution Reserve the filtrate 5 3 Calcium re precipitation Wash down the sides of the original beaker with hot 5 add 2 ml 12 M to the solution and heat to boiling to dissolve the precipitate 5 3 2 Pourthe hot solution through the paper catch ing the filtrate in a 250 ml beaker 5 3 3 Wash the beaker thoroughly with hot 5 pouring all washings through the paper and then wash the paper thoroughly with the HCI solution making
476. tite Basalt 102 43 9 49 9 Al203 4 0 16 0 Fe203 2 5 5 4 FeO 9 9 6 5 CaO 3 5 9 1 Na20 0 6 3 2 K20 0 2 1 5 MgO 34 3 6 3 TiO2 0 8 1 4 P205 0 1 0 4 MnO 0 2 0 3 CO d s EA6 6 Granite Sediment Upper Crust 70 8 44 5 552 14 6 10 9 15 3 1 6 4 0 2 8 1 8 0 9 5 8 2 0 19 7 8 8 3 5 1 1 2 9 4 1 1 9 1 9 0 9 2 6 5 2 0 4 0 6 1 6 0 2 0 1 0 3 0 1 0 3 0 2 13 4 These eight oxides make up 97 of the average ig neous rock and eight elements account for 99 of the weight All other elements can be considered to be minor or trace elements in most rock types TABLE MXRF 2 AVERAGE COMPOSITION OF IGNEOUS ROCK Percent Percent Percent by by by Oxide Weight Element Weight Volume 102 59 1 O 46 6 93 8 Al203 15 3 Si 27 7 0 86 Fe203 3 1 Al 8 1 0 47 FeO 3 8 Fe 5 0 0 43 CaO 5 1 Ca 3 6 1 0 Na20 3 8 Na 2 8 1 3 K20 3 1 K 2 6 1 8 MgO 3 5 Mg 2 1 0 3 TiO2 1 0 P205 0 3 MnO 0 1 H20 1 2 TOTAL 994 98 6 100 0 Safety Advisory 1 X rays can cause both somatic and teratogenic damage It is mandatory that workers wear a dosimeter badge service provided by Health and Welfare Canada Health Protection Branch Pregnant women should not work in the X ray laboratory Radiation is measured in terms of dose or dose rate The unit of biological radiation exposure is the RAD Radiation Absorption Dose which is the quantity of radiation dose of any kind alpha beta gamma or X radiation that results in the absorption of 1
477. tive in removing residual amounts of fluoride See Safety advisory Hydrochlonc Acid 37 w w 12 M dissolves most oxides sulfides and carbonates In combination with nitric acid 3 1 it forms aqua regia Sample Dissolution Nitric Acid 69 HNO w w 16 M oxidizes organic matter prior to perchloric acid attack Sulphuric Acid 96 HSO w w 18 M is used when a high boiling acid is required Most effective in removing residual amounts of fluoride but formation of sulfates can create problems with dissolution and with depressant effects during the determination by AAS Fluxes Lithium Metaborate Lithium tetraborate Used individually or in combination when total dis Solution is required May be used with graphite or platinum crucibles Sodium Carbonate NaCO fused in platinum crucibles is used primarily with classical rock analysis methods Sodium Hydroxide NaOH or KOH potassium hydroxide are used usual ly with nickel crucibles when a strongly alkaline flux is required Sodium Peroxide Na O is a powerful oxidant used to attack spinels zircon and sulfides Safety advisory CAUTION Exercise extreme care when using any acids and fluxes Their use should only be attempted after the appropriate MSDS sheets have been read and the safe handling and first aid procedures understood Acids should only be handled in a fume hood with proper ventilation and with proper protective equip ment
478. to just cover the sample 1 4 Add hot water to half fill the beaker if the sample is still coherent otherwise proceed to step 1 5 1 5 Add 6 g of Calgon and 6 g of bicarbonate of soda to the beaker containing the sample and E7 1 8 water This causes an exothermic reaction in which clay is dissolved and dispersed Cold water may be added to lessen the reaction After 30 minutes dispersal is complete and the residue may be washed and sieved If pyrite is present the production of sulphuric acid is avoided by adding 6 g of sodium bicarbonate and then boiling on a hotplate until disintegra tion occurs Wash the residue through 3 sieves An 18 mesh sieve is used to collect larger microfos sils a 85 and 170 mesh sieve is used to collect smaller microfossils If any undisintegrated rock fragments remain on the 18 mesh sieve repeat steps 1 5 1 6 Wash the residue from each sieve into filter papers in funnels and dry the residue Transfer the residue to dry bottles for sub sequent study MS3 1 Grain size Analysis GRAIN SIZE ANALYSIS Introduction TABLE GSA1 PARTICLE SIZE TABLE Detailed knowledge of the physical characteristics and AND SIEVE INFORMATION Structural properties of soils is essential in helping engineers determine soil behavior and performance in U S Mesh Inches Microns Millimeters a variety of construction condi
479. to the 50 ml mark with distilled water 3 10 Cover the tube with parafilm or a cap and mix well 3 11 Distribute samples for AAS determination see Note 4 NOTES 1 Ifthe sample is an ore material or is dark in colour 3 it is advisable to use a 100 ml PTFE beaker At this stage if the sample contains sulfides it will be necessary to add 3 ml of HNO prior to the addition of HF and cover the beaker with a watch glass Allow the sample to reflux for 15 minutes on a hot plate wash the watch glass with distilled water and add the HF The presence of minerals resistant to acid attack may be observed at this time Check values deter mined by AAS with those obtained by the XRF Screen Program The XRF Screen will be avail able only if chromium or barium have been re quested 4 Dilution factor for these solutions is 100 Acid concentration is 10 4 Sample Dissolution for the T4 and T5 Analyti cal Packages This preparation is a modification of Procedure 1 and requires fastidious attention to detail It was developed to provide a solution for the determination of rare earth elements and yttrium by ICP MS It is the procedure required when ICP MS is used for analytical measure ment Other elements determined with this solution are uranium thorium thallium hafnium and tantal lum 4 1 Preparation of 10 ppm Ruthenium Rhen ium Standard 4 1 1 Pipet 20 ml of 1000 ppm Ru solution and 20 ml of 1000 ppm Rh s
480. trated by the following set of equations for the example of mutual inter ference by analytes A and B CA obs CA true x1 CB true CB obs CB tme x2 CA true This is a pair of linear equations CA obs CA true x1 CB true CB obs x2CA tme CB true with solutions _ CA obs x1 CA obs CA true 1 x1 x2 and _ CB obs x2 CB obs CB true 1x12 Where the term x1x2 is very small it can be ignored The system can also be handled by matrix algebra since the linear equations can be rewritten as CO A CT where CO and CT are column matrices of observed and true concentrations respectively and A is a square matrix of the type xl x2 1 To evaluate this matrix equation one uses the inverse of the square matrix i e CO A x CT A CO A A x CT CT In this example the inverse matrix A is EA18 9 Traces ICP OES 1 1 2 1 1 x1 2 and the solution is found from the product 1 xl CA obs CA true 1 x2 1 CB obs CB true 1 x1x2 _ CA obs x1 CB obs CA true 1x12 Etc The advantage of the matrix approach becomes ap parent in highly complex systems such as the follow ing theoretical example Five elements A B C D E A interferes on B C E coefficients x1 x2 x3 B interferes on D E x4 x5 C interferes on A D x6 x7 D interferes on C x8 E interferes on A B C x9 x10 x11 Thus CA obs CA tr
481. u for corrected absorbance signal The above process is repeated for Channel B if in two channel operation two elements determined simultaneously 2 ENTER Enter Sample no When first sample no is entered all subsequent analyses will be incremented by one Auto zero and auto cal functions will not increment the sample num EA3 2 ber The I D of the sample currently being analyzed is displayed on the bottom of the CRT 1 IBM Compatible Auto Graphics 0 Off The graphics printer will serve only as an alphanumeric printer A hard copy of the CRT is made by keying the decimal point on the AA number pad 1 On The graphics printer will automatically trigger the CRT graphics after every integration cycle if peak area integration is selected with graphics 1 All data provides a hard copy of the CRT each time an absorbance profile is displayed if auto graphics was selected 2 Stats only lists sample number and statistical sum mary the graphics printer does not hard copy the CRT NOTE Do not take the graphics printer off line while itis printing doing so would lock up the AA s microprocessor 3 ENTER 0 Off deactivates the RS232C interface On 0 Printer used to transmit data to an external printer properly configured to accept data Protocol must be entered to use the ADS 200 system Enter default settings from next CRT dis plays CAUTION If not using the ADS 200 system do not select th
482. uality control programs involves the insertion of one subsample each of three in house reference materials a granite a basalt and a syenite into the routine analytical work on a monthly basis It is the precision data from this program that are used to derive our advertised analytical capabilities The stringency of the test allows us to have confidence that the figures we quote are realistic even if applied to multi year projects The rock powder samples are introduced blind into the routine workflow and are subject to no special procedures as often happens when an analyst is aware that QC samples are being run Research grade jobs require precisions to be sig nificantly better than those quoted above These are achieved by rigorous batch control The Laboratories has performed a blind study on in house basalt and granodiorite standards The data are produced below and indicate the precision typically to be expected when determined by XRF EA6 11 Majors XRF TABLE MXRF 4 IN HOUSE BASALT REFER ENCE MATERIAL MRB7 Component Mean Precision N 26 102 49 14 0 40 15 Al203 12 65 0 10 15 Fe203 13 61 0 20 15 MgO 6 13 0 18 15 CaO 9 53 0 08 15 Na20 2 45 0 14 15 TiO2 1 96 0 06 15 K20 0 69 0 01 15 P205 0 25 0 01 15 MnO 0 189 0 005 15 CO2 0 67 0 02 15 LOI 2 95 0 13 15 Total rock analysis is characterized by an analysis total including LOI and TOTAL VOLATILES of 100 for most samples If the total value lies outsi
483. ue CC true x9 CE true CB obs CB true x1 CA true x10 CE true CC obs CC true x2 CA true x8 CD true x11 CE true CD true x4 CB true x7 CC true CD obs CE true x3 CA true x5 CB true CE obs which in matrix form is CA obs 1 0x60 x9 CA true CB obs x1 10 0 x10 CB true CC obs x20 1 x8 x11 CC true CD obs O x4x7 1 0 CD true CE obs x3x5 0 0 1 CE true A programmable calculator or computer program can be used to solve the system Uncorrected concentra tion data from the spectrometer are corrected off line before reporting Although it is possible to correct for all of the possible interferences in a system including the sequential and mutual corrections outlined above it may not always be convenient or even significant to do so If omission of a particular correction factor will not appreciably alter the final concentration and or the error inherent EA18 10 in exclusion is smaller than that obtained from in strumental precision the correction can be ignored This is typically the case when either the magnitude of the coefficient is very small or the concentration of interferent is very low Corrections due to sequential or mutual interferences are generally found to be very low and are almost always ignored To Correct or Not to Correct The relative standard deviation contributed to a result by the omission of a particular interference correction can be written
484. ue to the yellow coloured complex formed by titanium with hydrogen peroxide in acid solution at 435 nm in a cell against a blank reagent containing 10 ml of 1 1 H5SO 5 Calculation of the results RM 5 2 To a series of 100 ml volumetric flasks add 10 ml of 1 1 HSO and dilute with distilled water to about 50 ml Add from a burette 0 25 ml a series of ali quots of the standard TiO solution 0 5 mg TiO ml to give 0 50 1 00 2 00 4 00 8 00 and 10 00 mg 100 ml and mix 5 3 Add 5 ml of phosphoric acid using a fast draining pipette and mix 5 4 Add 10 ml of 3 H O solution made fresh using a pipette mix and make it to 100 ml with distilled water and shake well 5 5 Measure the absorbance of the yellow coloured complex formed by the titanium with hydrogen peroxide in acid solution at 435 nm in a cell against a blank having all the reagents and 10 ml of 1 1 H SO 5 6 a calibration curve 5 7 Thecurve should be linear 5 8 The yellow coloured complex is very stable and reproducible 5 9 Use the relative absorbance of the sample at 435 nm to obtain the concentration of TiO per 100 ml of solution from the calibration curve mg TiO 1 100 TiO 5 x x Ies ml 1000 sample weight Quality Control The determination limit for this method is 0 02 TiO There is not enough data available to establish precision and accuracy for this m
485. ues The following procedure may be followed 1 1 The weight of the rock powder is recorded to four decimal places Pulverized rock powder weighing 300 400 mg is sealed in plastic using a bag sealing unit The container is marked using a indelible marker pen UTB 1 is used to make up a reference standard and either WHIN SILL the Open University irradiation standard or BHVO 1 are used to monitor quality within and between batches of samples 1 2 Up to twenty small baggies are placed in each cylinder for irradiation Normally there is no need for flux corrections when irradia tion is completed in a small reactor of the SLOWPOKE type EA20 1 Traces NAA 1 3 Samples are irradiated for 16 hours and counted 7 and 40 days after they are removed from the reactor 2 Determination of element concentrations The sample is affixed to the center of an aluminium plate so that it is flat and free of wrinkles The plate is inserted into a rack on the nose of the detector Data are acquired using a Canberra multi channel analyser MCA with the spectral regions of interest defined in Table NAA Each sample is counted for 5000 or more live seconds to achieve a 26 error of 10 or better for the peaks of interest Dead time must be 1546 or an alternative sample with lower dead time should be counted first The multi channel analyzer is equipped with two detectors ADC 1 and ADC 2 and collects counts simultaneously from bo
486. umber It functions exactly as selection 2 except that these curves do not have and do not require method numbers because they are stored solely by element To overwrite a furnace curve press STORE key type 2 and press ENTER and overwrite the desired curve by typing its appropriate number and pressing ENTER Press ENTER again to overwrite Typical Furnace Operation Steps FIRST Follow the Power On Sequence to begin SECOND Set the software parameters for furnace operation through the Mode menu See notes under AA Spectrometer Keyboard System Software NOTE Set option 3 of the Mode menu first i e single or dual channel with or without background Choose elements option 3 Check I O settings See notes Instrument Controls Keyboard on Video 22E Make sure Serial Printer is OFF if not using the ADS 200 system THIRD Set the instrument parameters on the AA spectrophotometer according to conditions stored in the microprocessor memory Recall Flame Condi tions Set wavelength bandpass hollow cathode lamp current background current See Section 4 2 page 4 16 of the Video 22E Operator s Manual for insertion and alignment of the hollow cathode lamp NOTE Adjust the PM voltage so that the energy meter is in the green zone Optimize alignment of the HCL by adjusting the knob located near each spring and by rotating the HCL The following is a list of parameters for elements currently being determined by graphite
487. ur ves instrument conditions and to review or change furnace methods The following menu is displayed when the RECALL key is pressed and if CTF is the method of atomization indicated in the Mode menu Recall 2 Instrument Conditions 3 Furnace Method by Element 4 Furnace Method by Matrix 5 Current Method 6 Furnace Curve 9 To exit 2 Will display the element table Select desired element and ENTER to display recommended instrument conditions HCL current bandwidth wavelength which are the same for flame and CTF measurements Press RECALL to retum to element table Press ENTER to give initiallization menu for CTF use then press RECALL to retum to Recall menu A second element may be entered for dual channel use 3 ENTER Will display available furnace methods for the current element of interest Select the desired fumace method by typing its repective number and pressing ENTER The furnace method is displayed on the CRT At this point if 1 is chosen Run as is the analysis will start after the RUN key on the 188 is pressed Pressing 2 Change will allow you to alter fumace parameters method title etc beginning with the matrix name Once the matrix name is chosen other parameters can be changed as indicated on the new menu see below 4 ENTER Will display available furnace methods for a given matrix to use with a different element Other options which follow are similar to those when 3 ENTER is pressed
488. use in a muffle furnace for 30 minutes at 1050 C see Note 4 Transferthe molten fusion mixture to a 250 ml Nalgene beaker containing 100 ml of 12 96 nitric acid Dissolve the sample using a magnetic stirrer and teflon coated stirring bar Complete dis solution requires about 20 minutes see Note 5 Filter the solution using 41 Whatman filter paper 12 5 cm into a 200 ml volumetric flask Wash the filter paper several times with dis tilled water and make to volume with same Solution is sent to AAS for determination of required element Further preparation for determination will be found in the section Trace Elements Determined by Flame Atomic Absorption NOTES 1 If the samples contain appreciable amounts of sulphide weighed samples in porcelain crucibles should be roasted in a muffle furnace at 650 C for three to four hours before mixing with the borate flux Organic matter should be ashed 2 For samples known to contain 30 iron oxide add about 15 mg of pure graphite powder to the porcelain crucible containing the flux and sample This will prevent the fused melt from sticking to the bottom of the graphite crucible during pouring 3 New graphite crucibles need to be conditioned in a muffle furnace at 1000 C for 15 minutes 4 It is important to maintain the fusion for 30 minutes for barium sulphate to be completely at tacked 5 If the dissolution is not allowed to take place at room temperature the
489. ution in the fraction finer in grain size than 62 microns but coarser MS4 10 than 2 25 microns is determined using the particle size analysis instrument equipped with a wet sensor The particle size distribution in the fraction finer than 2 25 microns is determined by conventional hydrometry 1 1 Upon receipt samples are place in drying cupboards for a week 1 2 The sample is broken in a soil breaker rolled and about 50 g of the 10 sieve fraction is retained for analysis 1 3 A 2 g sub sample consisting of a repre sentative fraction of the 10 mesh fraction is weighed and placed in a 250 ml jar and 20 ml of a dispersant is added a solution of sodium hexamethaphosphate in distilled water 40 g per liter 1 4 The 10 mesh fraction in the dispersant is wet sieved through 14 18 25 and 230 sieves Care is taken to wash any fine material through the sieve using a small amount of distilled water No more than 200 ml of dis tilled water should be used Particles resting on the four sieves 14 18 25 and 230 are washed onto filter papers dried in the oven at 110 C and then weighed to 0 001 g The 230 mesh particulates in the dispersant are poured into the original 250 ml jar and any residual particles are washed out The suspen sion is made up to 250 ml 1 5 As outlined below the 230 fraction is analyzed using the dry sensor on the particle size analysis system while the 230 fraction is analyzed usin
490. vernight Gently tap beakers to cause any droplets of acid condensed on the upper portion of the beaker walls to fall to the bottom Leave beakers on the hot plate until fumes cease Check for more droplets and repeat steps 1 6 and 1 7 until acid droplets have been removed To the dry residue add 2 ml of concentrated HNO and heat hot plate for 1 minute Remove beaker and add 0 5 ml of con centrated allowing any vigourous reac tion to subside before placing beaker on hot plate Use a teflon rod to break up the residue while adding 15 ml of distilled water Heat on the hot plate for 15 minutes or until dissolution appears complete Examine the beaker for any incompletely decomposed residue and record its presence for that sample see Note 2 Transfer the cooled solution to a 50 ml polypropylene centrifuge tube and bring to 25 ml mark using distilled water Cover the test tube with parafilm or a cap and mix well 1 16 Split the solution into two fractions using 17 x 100 mm polypropylene culture tubes for dis tribution to AAS and or ICP OES see Note 3 NOTES 1 A clean empty supplier HF dispensing bottle may be used for this purpose 2 The presence of minerals resistant to acid attack may be observed at this time Check determined values against values obtained with XRF Screen and ascertain whether fusion is required for these samples 3 Dilution factor for these fractions is 50 ICP O
491. weight made by the particles falling in this grain size interval e g D 12 Recalculation of data Hydrometry and sieve data for each sample are entered into ASCII file using a GWBASIC program GRAIN ANY This information is then combined with the data from the ASCII files for the wet and dry sensors using a program which generates an ASCII file and report Quality Control Analysis of the in house GLOGS soil standard should accompany each batch of samples Hydrometry deter minations on the GLOGS standard made without using stock material as the amount of this standard used in a hydrometry determination would be 50 g The method produces a slightly different gradation curve compared to the conventional ASTM method Productivity A technician should be able to complete 40 samples per week with the automatic system Grain size Analysis 2 MS4 13 Atterberg ATTERBERG LIMITS ASTM D423 66 Introduction The Atterberg Limits represent the liquid and plastic limits of a soil which in turn are used in the classifica tion The Atterberg limits are frequently used in specifica tions for controlling the type of soil used in a variety of engineering projects Procedure 1 1 The soil sample is placed on a glass plate and thoroughly mixed with distilled water Part of the soil mixture is then placed in the Liquid Limit device which consists ofa brass cup and carriage With a spatula soil is leveled a
492. with a request to save the new angle default yes R saves the new angle NO rejects the new angle The new angle is automatically stored in the parameter bank EA6 19 Majors XRF Optimization of Channel Parameters PHD Selection Window selection can be upgraded by PHD analysis PHD FE The system responds WINDOW 5 5 window default 2 often used TIME 1 time at point 1 s NOTE If PHD is done in manual mode the output is a numerical listing of counts If PHD is done in automatic mode a graphical display is output Select or confirm UPL and LWL settings and if necessary enter new values in the PB using the ACH mode To obtain total counts in window selected previously run PHD and after the first line has been printed type R to stop Storing Parameters After all channels have been entered they are automatically stored in memory at the microprocessor To store them on the disk under the same name as the databank type DPB For initial storage the system may ask for FILENAME to which the DB name is given In this example the instruction DPB creates or updates the file MAJORS PBK EA6 20 Majors XRF APPENDIX C SETTING UP AN ANALYTICAL PACKAGE Once a series of element channels has been established in the Parameter Bank they should be combined into an analytical package This requires the construction of various programs MP measurement program LP link program calculation parame
493. worn Proper ventilation will be required when handling fluxes which create a dust control problem 1 Hydrofluoric and perchloric acids require spe cial care in handling Hydrofluoric acid HF may only be used after training in the proper proce dures Its use is restricted to designated fumehoods Its hazard lies in the nature of the bum EA2 1 DAMPE UISSOLUTION which can result Very close attention should be paid to suspected skin contact and treatment ap plied immediately NEVER handle HF and HCIO without gloves proper eye protection and a lab coat 2 Non glass labware must be used when handling HF because the acid attacks silica in laboratory glassware Perchloric acid may only be used in designated perchloric acid fumehoods with operable scrubbing and or wash down facilities Washdown facilities are required in designated fumehoods to prevent the buildup of anhydrous perchloric salts which can become spontaneously flammable Explosions can result when organic perchlorates are formed Ensure that organic material such as alcohols organic solvents and paper products are kept away from the digestion area Organic material in the sample should be oxidized at a lower temperature with nitric acid prior to digestion with perchloric acid Decomposition by Acid Attack Apparatus Top loading electronic analytical balance reproducibility 0 001 g Polytetrafluoroethylene PTFE beakers 30 ml 50 ml 100 ml capacity
494. xide ALO STANDARD SOLUTIONS Use certified reference materials prepared in the same manner as the samples INSTRUMENT PARAMETERS Lamp Current ma 10 Wavelength nm 309 3 Spectral Band Pass nm 0 5 Flame Description Nitrous oxide acetylene Fuel rich reducing red cone INTERFERENCES Aluminium is partially ionized in a nitrous oxide acetylene flame The added strontium acts as an ionization buffer Interferences are dependent on flame conditions and burner height A fuel rich flame red cone decreases the effect Silicon depresses aluminium absorbance by the forma tion of an undissociated refractory complex This is minimized by the addition of Sr as well as matching standards and samples with respect to the major matrix elements NOTES 1 Fuel support ratio and burner height are critical in the determination at low levels of detection 2 Burner blockage although not as severe as with silica will occur with fuel rich flames Bracket samples and standards when reading absorbances Majors AA Calcium Oxide CaO STANDARD SOLUTIONS Use certified reference materials prepared in the same manner as the samples INSTRUMENT PARAMETERS Lamp Current ma 3 5 Wavelength nm 422 7 Spectral Band Pass nm 0 5 Flame Description Air acetylene Oxidizing fuel lean blue INTERFERENCES Silicon aluminium phosphate and sulphate depress the calcium absorbance These interferences can be controlled by intro
495. y shut down and the ignition spark will stop after 10 seconds Tum off the power wait a few seconds and tum on again If the flame photometer again fails to ignite referto the installation and maintenance manual Place a plastic cup 30 ml filled with lithium blank diluent solution on the sample tray Raise the tray to the limit of its travel Con tinue to aspirate lithium for 10 minutes oruntil the inside of the atomizer chamber is thoroughly wetted Refill the cup as neces sary Zero setting and calibration Set the range to 200 Leave on Dis play switch set to continuous Aspirate Li blank solution EA11 3 Sodium Potassium 5 2 3 Unlock the Set Li Standard control at lower right by turning the base of the control knob counter clockwise 5 2 4 Setthe lithium standard meter to the centre of the green band 5 2 5 Relockthe control by turning the base careful ly clockwise as far as it will go 5 2 6 Unlock the Na and K zero controls and adjust them until both indicators read 000 A read ing of 999 indicates that the setting is below zero and the appropriate control should be carefully turned clockwise until the reading is 000 Relock both controls 5 2 7 Remove the lithium blank solution cup 5 2 8 Insert a fresh sample of the desired Na K standard 5 2 9 Verify that the lithium standard meter reads in the centre of the green band Readjust if necessary using Set Li standard contr
496. ydrochloric acid 6 8 M phosphoric acid 15 M manganese sulphate MnSO 4H O mercuric chloride HgCl Procedures 1 Reagent Preparation 1 1 1 3 1 3 1 1 3 2 1 3 3 1 3 4 1 3 6 EA15 2 Saturated boric acid Prepare a saturated solu tion by adding approximately 900 ml of recently boiled and cooled to room tempera ture distilled water to 50 g of boric acid crystals in a flask It is convenient to employ three one liter beakers for the purpose of providing sufficient water see Additional Notes below Decomposition Solution Prepare a solution of recently boiled and cooled to room temperature distilled water sulphuric and hydrofluoric acids in a 1 1 1 volume ratio using the teflon beaker Approximately one hundred ml total volume is generally suffi cient for this purpose N 10 0 1 N Standard Potassium Perman ganate Weigh 32 0 g of potassium perman ganate crystals Transfer approximately 2 liters of recently boiled and cooled distilled water to a 2 liter beaker Add the potassium permanganate crystals to the contents of the 2 liter beaker Heat to boiling and keep hot for one hour Cover and let stand overnight Filter the solution through glass wool into the 10 liter permanganate container Add 8 liters of recently boiled and cooled distilled water and mix the solution thorough ly 1 4 1 5 1 6 1 6 1 1 6 2 1 6 3 Allow to stand overnight
497. zable substances to eliminate the need for addition of K to the sample solution 2 The air acetylene flame in the emission mode generates excessive signal to noise levels ANALYTICAL CAPABILITIES Determination Limit ppm 3 Precision at the 95 confidence limit 20 at 10X determination limit 30 ppm is 3 ppm absolute Manganese STANDARD SOLUTIONS Use 100 ppm solution prepared from 1000 ppm mixed custom stock solution to prepare working standards of 0 5 1 0 2 0 and 4 0 ppm INSTRUMENT PARAMETERS Lamp Current ma 5 0 Wavelength nm 219 5 Spectral Band Pass nm 0 2 Background Correction OFF Flame Description Air acetylene oxidizing fuel lean blue WORKING CONDITIONS Sensitivity 1 ppm Mn solution reads 0 300 absorbance Calibration Set 1 00 ppm to read 1 00 Working range Q 5 to 4 0 ppm INTERFERENCES The presence of phosphate perchlorate iron nickel and cobalt will depress the Mn absorbance when a reducing air acetylene flame is used USE an oxidiz ing flame Silicon depresses the signal and is overcome by incor poration of 0 2 CaCl in samples and standards NOTES 1 The presence of silica in samples fused with lithium metaborate may cause a depression in the Mn absorbance if insufficient Ca is present in the sample Use certified reference materials as calibration standards See Major Elements Determined by Flame Atomic Absorption in this manual 2 The closely spaced triplet for

The analysis of geological materials, volume 2

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