1、Designation: E1600 07E1600 13Standard Test Method forDetermination of Gold in Cyanide Solutions by FlameAtomic Absorption Spectrometry1This standard is issued under the fixed designation E1600; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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 determination of gold in ore processing cyanide solution in the ran
3、ge from 0.3 g/mL to 10.0g/mL of gold by direct aspiration into an atomic absorption spectrophotometer.spectrometer.1.1.1 This test method may also be applied to cyanide leach solutions from metallurgical evaluation procedures.1.2 The values stated in SI units are to be regarded as standard. No other
4、 units of measurement are included in this standard.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
5、regulatorylimitations prior to use. Specific precautions are given in 8.1, 8.38.1.1, 8.5, Section 9, and 10.4.1.111.2.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1293 Test Methods for pH of WaterD6888 Test Method forAvailable Cyanide with Ligand Displacement and
6、Flow InjectionAnalysis (FIA) Utilizing Gas DiffusionSeparation and Amperometric DetectionD7237 Test Method for Free Cyanide with Flow InjectionAnalysis (FIA) Utilizing Gas Diffusion Separation andAmperometricDetectionE29 Practice for Using Significant Digits in Test Data to Determine Conformance wit
7、h SpecificationsE50 Practices forApparatus, Reagents, and Safety Considerations for ChemicalAnalysis of Metals, Ores, and Related MaterialsE135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE173 Practice for Conducting Interlaboratory Studies of Methods for Chem
8、ical Analysis of Metals (Withdrawn 1998)3E663 Practice for Flame Atomic Absorption Analysis (Withdrawn 1997)3E882 Guide for Accountability and Quality Control in the Chemical Analysis LaboratoryE1024 Guide for Chemical Analysis of Metals and Metal Bearing Ores by Flame Atomic Absorption Spectrophoto
9、metry(Withdrawn 2004)3E1060 Practice for Interlaboratory Testing of Spectrochemical Methods of Analysis (Withdrawn 1997)3E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method3. Terminology3.1 DefinitionsFor definitions of terms used in this test m
10、ethod, refer to Terminology E135.4. Summary of Test Method4.1 The sample solution is collected and preserved with sodium hydroxide, if necessary, by careful adjustment of pH. The testsolution is filtered and gold content is determined by flame atomic absorption spectrophotometry.spectrometry.1 This
11、test method is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.Current edition approved June 1, 2007April 1, 2013. Published
12、June 2007June 2013. Originally approved in 1994. Last previous edition approved in 20022007 asE1600 02.E1600 07. DOI: 10.1520/E1600-07.10.1520/E1600-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Sta
13、ndardsvolume information, refer to the standards Document 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 ch
14、anges have been made to the previous version. Becauseit may 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 off
15、icial document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 In primary metallurgical processes for gold bearing ores, gold is extracted with an alkaline cyanide solution. Metallurgicalaccounting, process
16、control, and ore evaluation procedures depend on accurate, precise, and prompt measurements of the goldconcentrations.5.2 This test method is a comparative referee method for compliance with compositional specifications for metal content.concentration or to monitor processes. It is assumed that all
17、who use this proceduremethod will be trained analysts capable ofperforming common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equippedlaboratory and that proper waste disposal procedures will be followed. Follow under appropriate quality cont
18、rol practices such asthose described in Guide E882., and that proper waste disposal procedures will be followed.6. Interferences6.1 Elements normally found in ore processing cyanide solutions do not interfere. Use of instrumental background correctionis required to compensate for nonspecific absorpt
19、ion interferences in the flame.7. Apparatus7.1 Atomic Absorption Spectrophotometer,Spectrometer, equipped with background correction and capable of measuring goldat the 242.8-nm wavelength using an air and acetylene flame over a linear range from 0.3 g/mL to 10.0 g/mL gold.8. Reagents and Materials8
20、.1 Gold Calibration Solutions (0.5, 1.0, 2.0, 5.0, 10.0) g/mLIn a fume hood, pipette 10 mL of Gold Standard Solution A(8.2) into a 1-L volumetric flask containing 100 mL of Sodium Cyanide-Sodium Hydroxide Solution (8.5). Dilute to volume andmix (10 g/mL).8.1.1 Pipette (5, 10, 20, and 50) mL of the 1
21、0 g/mL gold calibration solution into each of four 100-mL volumetric flasks,respectively. Add 10 mL of Sodium Cyanide-Sodium Hydroxide Solution (8.5), dilute to volume, and mix.WARNINGReaction of acid or chlorine and cyanide solutions releases toxic hydrogen cyanide or cyanogen chloride gases.Prepar
22、e in a fume hood.8.2 Gold Standard Solution A (1 mL 1.0 g Au)Weigh 1.000 g of gold metal (99.99 % minimum purity) and transfer to a1-L beaker in a fume hood. Add 200 mL of water, 80 mL of HCl, and 50 mL of HNO3 (1 + 1). Boil gently to expel NOx fumes,cool, transfer to a 1-L volumetric flask, dilute
23、to volume, and mix.8.2.1 A certified reference solution meeting these specifications may also be used.8.3 Reference SolutionDilute 100 mL of Sodium Cyanide-Sodium Hydroxide Solution (8.5), to 1 L with water.8.4 Sodium Cyanide.8.5 Sodium CyanideSodium Hydroxide SolutionDissolve 10 g of sodium hydroxi
24、de and 10 g of sodium cyanide in 1 L ofwater.WARNING The preparation, storage, use, and disposal of sodium cyanide solutions require special care and attention.Avoidany possibility of inhalation, ingestion, or skin contact with the compound, its solution, or its vapors.Work only in a well-ventilated
25、hood.8.6 Sodium Hydroxide.8.7 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee onAnalytical Reagents of theAmerican Chemical Society werewhere suchspecifications are availa
26、ble.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.8.8 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water as define
27、d byconforming to Type I or II of Specification D1193. Type III or IV may be used if they effect no measurable change in the blankor sample.8.3 Sodium CyanideSodium Hydroxide SolutionDissolve 10 g of sodium hydroxide (NaOH) and 10 g of sodium cyanide(NaCN) in 1 L of water. (Warning The preparation,
28、storage, use, and disposal of NaCN solutions require special care andattention. Avoid any possibility of inhalation, ingestion, or skin contact with the compound, its solution, or its vapors. Work onlyin a well-ventilated hood. Refer to Practices E50.)4 Reagent Chemical, American Chemical Society Sp
29、ecifications, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Reagent CHemicals and Standards, by Joseph Rosin, D. Nostrand Co., Inc., New York, NY, and the United States Pharmacopeia andNational Formulary, U.S.
30、Pharmaceutical Convention, Inc., (USPC), Rockville, MD.E1600 1328.4 Gold Standard Solution AWeigh 1.000 g of gold metal (99.99 % min purity) and transfer to a 1-L beaker in a fume hood.Add 200 mL of water, 80 mL of HCl, and 50 mL of HNO3 (1 + 1). Boil gently to expel NOx fumes, cool, transfer to a 1
31、-Lvolumetric flask, dilute to volume, and mix.8.4.1 A certified reference solution meeting these specifications may also be used.8.5 Gold Calibration Solutions (0.5, 1.0, 2.0, 5.0, 10.0 g/mL)In a fume hood, pipette 10 mLof gold standard SolutionAintoa 1-L volumetric flask containing 100 mL of sodium
32、 cyanide-sodium hydroxide solution. Dilute to volume and mix (10 g/mL).(WarningReaction of acid or chlorine and cyanide solutions releases toxic hydrogen cyanide or cyanogen chloride gases.Prepare in a fume hood.)8.5.1 Pipette 5, 10, 20, and 50 mL of the 10 g/mL gold calibration solution into each o
33、f four 100-mL volumetric flasks,respectively. Add 10 mL of sodium cyanide-sodium hydroxide solution, dilute to volume, and mix.8.6 Reference SolutionDilute 100 mL of sodium cyanide-sodium hydroxide solution to 1 L with water.9. Hazards9.1 For precautions to be observed in this method, refer to Pract
34、ice E50.9.2 Hydrogen cyanide and alkali cyanide are very toxic substances. Use an efficient fume hood. Cyanide must be disposed ofwith care, avoiding contact with acid that releases hydrogen cyanide gas. Oxidation of cyanide with chlorine or hypochlorite mustbe carried out at high pH (greater than 1
35、1) to prevent generation of toxic cyanogen chloride gas.9.3 See specific warnings in 8.1, 8.1.1, 8.5, and 11.2.10. Sampling and Sample Preparation10.1 Collect, store, and dispose of the sample in accordance with Practices E50.10.2 PreservationDetermine the pH of the solution immediately after sampli
36、ng in accordance with Test Method D1293. If thepH of the sample is less than 10, adjust the pH with small additions of solid sodium hydroxide, followed by mixing, until the pHis greater than 10.10.3 Samples may be preserved to pH 11 or higher if they are also being tested for free and weak acid diss
37、ociable cyanide inaccordance with Test Methods D6888 or D7237.10.4 Test SolutionsFilter two 50-mL portions of preserved sample solution through a coarse-porosity filter paper.11. Preparation of Apparatus11.1 Follow the instrument manufacturers instructions to adjust the instrument for gold at 242.8
38、nm. Warm up the instrumentwith background correction applied in accordance with the manufacturers instructions. With the gold hollow cathode lamp inposition, energized and stabilized, adjust the wavelength to maximize the energy response of the 242.8-nm line. Light the burner,allow it to reach therm
39、al equilibrium, and adjust the instrument to zero while aspirating water.11.2 The use of an air-acetylene, lean, blue flame and caustic stabilized drain bottle is required.WARNINGReaction of acid and cyanide solutions in the burner chamber drain bottle may release toxic hydrogen cyanidegas. Add an e
40、xcess of sodium hydroxide to the drain bottle to maintain the pH above eleven.11.3 Determine if the instrument precision is acceptable as follows:11.3.1 Calibrate the instrument in accordance with the manufacturers instructions in absorbance. Set the absorbance to zerowhile aspirating the reference
41、solution.11.3.2 Aspirate the calibration solutions in order of increasing concentration, and select a calibration solution in the absorbancerange from 0.2 to 0.4.11.3.3 Alternate readings on the selected calibration solution and reference solution, and calculate the standard deviation of thereadings
42、 on the selected calibration solution using accepted statistical methods. Measure the standard deviation in this way atincreased measurement integration times until a relatively constant value is achieved.11.3.4 If the standard deviation under these conditions is greater than 1 % of the average abso
43、rbance, determine the cause ofthe variability (for example, deposits in the burner or clogged capillary), and take corrective action.11.3.5 If the minimum requirements are not met, do not use the instrument with this test method until the required stability isobtained.11.3.6 Collect all instrumental
44、 measurements for the test method using the instrumental settings which gave the optimumprecision of measurement on the selected calibration solution.11.4 Linearity of Instrument ResponseDetermine if the instrument response is acceptable as follows:11.4.1 Record absorbance measurements for each of t
45、he calibration solutions and the reference solution, prior to determiningsamples.11.4.2 Adequate instrument response is obtained if the difference between the 5-g/mL calibration solution and the 10-g/mLcalibration solution is sufficient to permit estimation of 150 of the difference between them.E160
46、0 13311.4.3 Adequate linearity is confirmed if the slope of the calibration curve between the 5 g/mL and 10 g/mL calibrationsolutions is at least 90 % of the slope between the reference solution and the 0.5-g/mL calibration solution.12. Calibration12.1 Calibrate the instrument in accordance with the
47、 manufacturers instructions in absorbance or gold concentration.13. Procedure10.1 Collect, store, and dispose of the sample in accordance with Practices E50.10.2 Determine the pH of the solution immediately after sampling in accordance with Test Method D1293. If the pH of thesample is less than 10,
48、adjust the pH with small additions of solid sodium hydroxide, followed by mixing, until the pH is greaterthan 10.10.3 Test SolutionsFilter two 50-mL portions of sample solution through a coarse-porosity filter paper.13.1 Photometry: High-Precision Method:13.1.1 FollowAdjust the instrument manufactur
49、ers instructions to adjust the instrument for gold at 242.8 nm. Warm up theinstrument with background correction applied in accordance with the manufacturers instructions. With the gold hollow cathodelamp in position, energized and stabilized, adjust the wavelength to maximize the energy response of the 242.8-nm line. Light theburner, allow it to reach thermal equilibrium, and adjust the instrument to zero while aspirating water.to zero with the referencesolution and measure the test sample solution to determine its place in the o
