1、Designation: E1446 05E1446 13Standard Test Method forChemical Analysis of Refined Gold by Direct CurrentPlasma Atomic Emission Spectrometry 1This standard is issued under the fixed designation E1446; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the analysis of refined gold for the following elements having th
3、e following chemical compositionlimits:Element Concentration Range, ppmElement Content Range, g/gCopper 17 to 300Iron 6 to 150Lead 17 to 100Palladium 7 to 350Silver 17 to 5001.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
4、1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Doc
5、uments2.1 ASTM Standards:2B562 Specification for Refined GoldE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE50 Practices forApparatus, Reagents, and Safety Considerations for ChemicalAnalysis of Metals, Ores, and Related MaterialsE135 Terminology
6、Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE173 Practice for Conducting Interlaboratory Studies of Methods for Chemical Analysis of Metals (Withdrawn 1998)3E882 Guide for Accountability and Quality Control in the Chemical Analysis LaboratoryE1097 Guide for Determination
7、of Various Elements by Direct Current Plasma Atomic Emission SpectrometryE1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method3. Terminology3.1 DefinitionsFor definitions of terms used in this test method, refer to Terminology E135.4. Summary of T
8、est Method4.1 The sample is dissolved with acids. Calibration solutions are prepared from pure reagents to match the sample matrix.Analysis is performed with the d-c argon direct-current plasma opticalatomic emission spectrometer. Element concentrationscon-tents are measured by comparing emission in
9、tensities from the sample with those of the calibration solutions. Copper is measuredat 327.3 nm or 324.7 nm; iron at 259.9 nm; lead at 405.7 nm; palladium at 340.4 nm; and silver at 328.0 nm or 338.3 nm.1 This test method is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for M
10、etals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.05 on Cu, Pb, Zn, Cd, Sn, Be, Precious Metals, their Alloys, and Related Metals.Current edition approved Oct. 1, 2005Oct. 1, 2013. Published December 2005October 2013. Originally approved in 1992. Last previous ed
11、ition approved in 19972005as E1446 92 (1997)E1446 05.1. DOI: 10.1520/E1446-05.10.1520/E1446-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document
12、 Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit m
13、ay not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Har
14、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This test method for the analysis of fine gold is primarily intended to test such material for compliance with compositionalspecifications. It is assumed that all who use this test method will be train
15、ed analysts capable of performing common laboratoryprocedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory and operated inaccordance with Guide E882.6. Interferences6.1 Spectral line interferences and spectrochemical background effects are overc
16、ome by preparing a matrix-matched calibrationstandard series to approximate the prepared sample.6.2 The analyte wavelengths mentioned herein have been previously evaluated for spectral line interferences and found to bethe optimum emission wavelengths for refined gold sample testing. Alternative wav
17、elengths, if shown to be free of interferences,may also be used.7. Apparatus7.1 D-C Argon Plasma OpticalAtomic Emission SpectrometerThe instrument must be equipped with a sample nebulizationsystem compatible with mineral acids and with test solutions containing 4 % total solids. Follow the manufactu
18、rers instructionsfor installation and operation.8. Reagents and Materials8.1 ArgonPurity: 99.998 % minimum.8.2 Copper Standard Solution (1 mL = 1.0 mg Cu)Transfer 1.000 g of copper metal (purity: 99.9 % minimum) to a 400-mLbeaker.Add 60 mLof HNO3 (1+1) (1 + 1) in 10-mLincrements and heat gently on a
19、 hot plate. When dissolution is complete, cool,then transfer to a 1-L volumetric flask. Dilute to volume with HNO3 (1+99) (1 + 99) and mix. This solution is stable for at leastsix months.8.3 Iron Standard Solution (1 mL = 1.0 mg Fe)Transfer 1.000 g of iron metal (purity: 99.9 % minimum) to a 400-mL
20、beaker.Add 50 mL of HCl plus HNO3 (4+1) (4 + 1) and heat gently on a hot plate. When dissolution is complete, cool and then transferto a 1-L volumetric flask. Dilute to volume with HCL (1+99) (1 + 99) and mix. This solution is stable for six months.8.4 Lead Standard Solution (1 mL = 1.0 mg Pb)Transf
21、er 1.000 g of lead metal (purity: 99.9 % minimum) to a 400-mLbeaker.Add 50 mL of HNO3 (1+4) (1 + 4) and heat gently on hot plate to dissolve and then cool. Transfer the lead solution to a 1-Lvolumetric flask, dilute to volume with water, and mix. This solution is stable for six months.8.5 Matrix Gol
22、dGold purity must be a minimum 99.9999 % based on total metallic impurities.8.6 Palladium Standard Solution (1 mL = 1.0 mg Pd)Transfer 1.000 g of palladium metal (purity: 99.9 % minimum) to a400-mL beaker. Add 50 mL of HCl plus HNO3 (4+1) (4 + 1) and heat gently on a hot plate. When dissolution is c
23、omplete, cool,then transfer to a 1-L volumetric flask and dilute to volume with HCl (1+99) (1 + 99) and mix. This solution is stable for sixmonths.8.7 Silver Standard Solution (1 mL = 1.0 mg Ag)Transfer 1.000 g of silver metal (purity: 99.9 % minimum) to a 400-mLbeaker. Add 60 mL of HNO3 (1+1) (1 +
24、1) and heat gently on a hot plate. When dissolution is complete, cool, then transfer to a1-L volumetric flask, dilute to volume with HNO3 (1+99), (1 + 99), and mix. This solution should be stored in an amber glasscontainer or in the dark. This solution is stable for at least six months. Any chloride
25、s must be kept away from this solution or thesilver will be precipitated.NOTE 1Commercially available certified or traceable element standards may also be used for calibration.9. Hazards9.1 For precautions to be observed in the use of certain reagents and equipment, refer to Practices E50.9.2 The ul
26、traviolet radiation from the plasma must be shielded at all times to prevent eye damage.9.3 All dissolution by acids must be performed under a hood with proper ventilation.10. Sampling10.1 For appropriate procedures on sampling the materials covered by this test method, refer to Specification B562.1
27、1. Interlaboratory Studies11.1 This test method was evaluated in accordance with Practice E173. Practice E173 has been replaced by Practice E1601. TheReproducibility Index, R2 of Practice E173 corresponds to the Reproducibility Index R of Practice E1601. Likewise theRepeatability Index R1 of Practic
28、e E173 corresponds to Repeatability Index r of Practice E1601.E1446 13212. Calibration12.1 Calibration Solutions:12.1.1 Master Analyte SolutionClean a 100-mL volumetric flask by boiling with 10 mL of HCl (1+1) (1 + 1) for 10 min andrinsing with water. Add 30 mL of HCl and transfer by means of a pipe
29、t the amounts of standard solutions listed in Table 1. Diluteto the mark and mix. Silver will not precipitate as silver chloride because of the presence of excess HCl. This solution is stablefor no longer than five days.12.1.2 High Calibration SolutionWeigh 2.000 g60.003 g of matrix gold and transfe
30、r to a 50-mLvolumetric flask, previouslycleaned by boiling with HCl (1+1) (1 + 1) for 10 min and rinsing with water. Add 15 mL of HCl plus HNO3 (4+1) (4 + 1) andheat gently until dissolved. If the gold does not completely dissolve, add 10 mL of HCl plus HNO3 (4+1) (4 + 1) and heat gentlyto complete
31、dissolution. Cool, then transfer by pipet 10 mL of master analyte solution and dilute to volume with HCl (1+2), (1+ 2), and mix. This solution is equivalent to 300 ppmg/g copper, 100 ppmg/g iron, 100 ppmg/g lead, 300 ppmg/g palladium,and 500 ppmg/g silver in the matrix gold.12.1.3 Medium Calibration
32、 SolutionWeigh 2.000 g 6 0.003 g of matrix gold and transfer to a 50-mL volumetric flask,previously cleaned by boiling with HCl (1+1) (1 + 1) for 10 min and rinsing with water. Add 15 mL of HCl plus HNO3 (4+1) (4+ 1) and heat gently until dissolved. If the gold does not dissolve completely, add 10 m
33、L of HCl plus HNO3 (4+1) (4 + 1) andheat gently to complete dissolution. Cool, then transfer by pipet 5 mLof the master analyte solution and dilute to volume with HCl(1+2), (1 + 2), and mix. This solution is equivalent to 150 ppmg/g copper; 50 ppmg/g iron; 50 ppmg/g lead; 150 ppmg/gpalladium; and 25
34、0 ppmg/g silver in the matrix gold.12.1.4 Low Calibration SolutionWeigh 2.000 6 0.0032.000 g 6 0.003 gg of matrix gold and transfer to a 50-mL volumetric flask, previously cleaned by boiling with HCl (1+1) (1 + 1) for 10 min andrinsing with water. Add 15 mL of HCl plus HNO3 (4+1) (4 + 1) solution an
35、d heat gently until dissolved. If the gold does notcompletely dissolve, add 10 mL of HCl plus HNO3 (4+1) (4 + 1) and heat gently to complete dissolution. Cool, then transfer bypipet 1 mL of master analyte solution and dilute to volume with HCl (1+2), (1 + 2), and mix. This solution is equivalent to
36、30ppmg/g copper; 10 ppmg/g iron; 10 ppmg/g lead; 30 ppmg/g palladium; and 50 ppmg/g silver in the matrix gold.12.1.5 Blank Calibration SolutionWeigh 2.000 g 6 0.003 g of matrix gold and transfer to a 50-mL volumetric flask,previously cleaned by boiling with HCl (1+1) (1 + 1) for 10 min and rinsing w
37、ith water. Add 15 mL of HCl plus HNO3 (4+1) (4+ 1) solution and heat gently until dissolved. If the gold does not completely dissolve, add 10 mL of HCl plus HNO3 (4+1) (4 +1) and heat gently to complete dissolution. Cool and dilute to volume with HCl (1+2) (1 + 2) and mix. This solution is equivalen
38、tto 0 ppmg/g copper; 0 ppmg/g iron; 0 ppmg/g lead; 0 ppmg/g palladium; and 0 ppmg/g silver in the matrix gold.12.2 Instrument OptimizationAdjust all instrumental parameters according to the instrument manufacturers recommendedoperating practices. Use the high calibration solution when aligning optic
39、s and entrance slit positions. The element emissionwavelengths given in Table 2 have been shown to be linear and interference-free for refined gold matrices.12.3 Instrument CalibrationFollowing the instrument manufacturers instructions, calibrate the spectrometer using thelow-calibration solution an
40、d the high-calibration solution at the wavelengths listed in 12.2 and using three, 8-s integrations. If theinstrument will only accept a high standard and a blank, use the high-calibration solution and the blank calibration solution. Rinsethe aspiration system with HCl (1+2) (1 + 2) for at least 15
41、s between calibration solutions.12.4 Calibration VerificationAnalyze the high, low, or blank and medium calibration solutions using the instrumentmanufacturers recommended procedure. If all values are not within 5 % of the expected value, repeat the calibration procedure.13. Procedure13.1 Test Solut
42、ion:13.1.1 Weigh 1.000 g60.001 g of the sample and transfer to a 25-mLvolumetric flask, previously cleaned by boiling with HCl(1+1) (1 + 1) for 10 min and rinsing with water. Add 7 mL of HCl plus HNO3 (4+1) and heat gently until dissolved. If the sampledoes not completely dissolve or silver chloride
43、 is seen as a precipitate, add 5 mL of HCl plus HNO3 (4+1) (4 + 1) and heat gentlyto complete the dissolution. Cool, then dilute to volume with HCl (1+2), (1 + 2), and mix.13.1.2 For the determination of each element, aspirate the test solution and record its concentration, using the instrumentmanuf
44、acturers recommended procedure. Verify the calibration after every four sample determinations. If the measured values forTABLE 1 Master Analyte SolutionElement Standard Solution, mL Master Analyte Solution FinalConcentration, g/mLmg/LCopper 6 60Iron 2 20Lead 2 20Palladium 6 60Silver 10 100E1446 133t
45、he calibration solutions are not within 5 % of expected values, repeat the calibration procedure and the sample measurement.Aspirate HCl (1+2) (1 + 2) for at least 15 s after each test or calibration solution.13.1.3 As an alternative to verifying calibration, the drift correction procedure as descri
46、bed in Guide E1097 may be used.14. Calculation14.1 This test method is designed so that direct reading instruments will provide results in parts per million weight concentrationg/g content in the refined gold sample material.15. Precision and Bias15.1 Precision4This test method was tested in an inte
47、rlaboratory testing program with seven participating laboratories. Threesamples were tested for the determination of copper, silver, palladium, and lead, and four samples were tested for the determinationof iron. The results are summarized in Table 3.15.2 BiasNo information on the accuracy of this t
48、est method is known because at the time it was tested, no certified referencematerials were available. Users are encouraged to employ suitable reference materials if available to verify the accuracy of themethod in their laboratory.4 Supporting data have been filed at ASTM International Headquarters
49、 and may be obtained by requesting Research Report RR:E01-0300.TABLE 2 Element Emission WavelengthsElement Wavelength, nm Alternate Wavelength, nmCopper 327.3 324.7Iron 259.9 .Lead 405.7 .Palladium 340.4 .Silver 328.0 338.3TABLE 3 Statistical InformationElement Sample Test Mean,ppmg/gA r, ppmg/gA R, ppmg/gACopper 1A 111.2 3.83 6.302A 311.4 7.73 8.563A 8.0 0.95 1.08Iron 1A 4.1 0.93 1.532A 4.3 0.49 1.313A 2.4 0.82 1.224A 141.3 2.40 6.81Lead 1A 31.2 0.78 1.492A 72.1 2.84 3.293A 18.8 0.67 1.33Palladium 1A 339.1 10.97 15.832A 106
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