1、Designation: E1600 15Standard Test Methods forDetermination of Gold in Cyanide Solutions1This standard is issued under the fixed designation E1600; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the determination of gold inore processing cyanide solutions within the following ranges:MethodApplication Range,g/m
3、LInductively Coupled Plasma Mass Spectrometry 0.001 to 0.500Flame Atomic Absorption Spectrometry 0.300 to 10.0NOTE 1The lower limit for the Inductively Coupled Plasma MassSpectrometry Method, 0.001 g/mL, was set following the guidance ofPractice E1601. The reproducibility Index, R, was calculated us
4、ing thetotal standard deviation for the lowest concentration Youden pair solution.1.1.1 These test methods may also be applied to cyanideleach solutions from metallurgical evaluation procedures.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are include
5、d in thisstandard.1.3 The test methods appear in the following order:Method SectionsFlame Atomic Absorption Spectrometry 916Inductively Coupled Plasma Mass Spectrometry 17241.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibili
6、ty of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tions are given in 11.1, 11.1.1, 11.5, and 12.2.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Wa
7、terD1293 Test Methods for pH of WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD5673 Test Method for Elements in Water by InductivelyCoupled PlasmaMass SpectrometryD6888 Test Method for Available Cyanide with LigandDisplacement and Flow
8、 InjectionAnalysis (FIA) UtilizingGas Diffusion Separation and Amperometric DetectionD7237 Test Method for Free Cyanide with Flow InjectionAnalysis (FIA) Utilizing Gas Diffusion Separation andAmperometric DetectionE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Sp
9、ecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical
10、 Analysis of Metals (Withdrawn1998)3E882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE1060 Practice for Interlaboratory Testing of Spectrochemi-cal Methods of Analysis (Withdrawn 1997)3E1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performanc
11、e of an Analytical Method3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology E135.4. Significance and Use4.1 In primary metallurgical processes for gold bearing ores,gold is extracted with an alkaline cyanide solution. Metallur-gical accounting, proc
12、ess control, and ore evaluation proce-dures depend on accurate, precise, and prompt measurementsof the gold concentrations.4.2 These test methods are comparative referee methods forcompliance with compositional specifications for metal con-centration or to monitor processes. It is assumed that all w
13、house these methods will be trained analysts capable of perform-ing common laboratory procedures skillfully and safely. It is1These test methods are under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and are the directresponsibility of Subcomm
14、ittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved April 1, 2015. Published May 2015. Originallyapproved in 1994. Last previous edition approved in 2013 as E1600 13. DOI:10.1520/E1600-15.2For referenced ASTM standards, visit the ASTM website, www.astm.o
15、rg, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harb
16、or Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1expected that work will be performed in a properly equippedlaboratory under appropriate quality control practices such asthose described in Guide E882, and that proper waste disposalprocedures will be followed.5. Hazards5.1 For p
17、recautions to be observed in these methods, refer toPractice E50.5.2 Hydrogen cyanide and alkali cyanide are very toxicsubstances. Use an efficient fume hood. Cyanide must bedisposed of with care, avoiding contact with acid that releaseshydrogen cyanide gas. Oxidation of cyanide with chlorine orhypo
18、chlorite must be carried out at high pH (greater than 11) toprevent generation of toxic cyanogen chloride gas.5.3 See specific warnings in 11.1.1, 11.5, and 12.2.6. Sampling and Sample Preparation6.1 Collect, store, and dispose of the sample in accordancewith Practices E50.6.2 PreservationDetermine
19、the pH of the solution imme-diately after sampling in accordance with Test Method D1293.If the pH of the sample is less than 10, adjust the pH with smalladditions of solid sodium hydroxide, followed by mixing, untilthe pH is greater than 10.6.3 Samples may be preserved to pH 11 or higher if they are
20、also being tested for free and weak acid dissociable cyanide inaccordance with Test Methods D6888 or D7237.6.4 Test SolutionsFilter two 50-mL portions of preservedsample solution through a coarse-porosity filter paper.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beuse
21、d in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of s
22、ufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Type I or II of Specification D1193. Type III or IV may beused if they effect no measur
23、able change in the blank orsample.FLAME ATOMIC ABSORPTION SPECTROMETRY8. Summary of Test Method8.1 The sample solution is collected and preserved withsodium hydroxide, if necessary, by careful adjustment of pH.The test solution is filtered and gold content is determined byflame atomic absorption spe
24、ctrometry.9. Interferences9.1 Elements normally found in ore processing cyanidesolutions do not interfere. Use of instrumental backgroundcorrection is required to compensate for nonspecific absorptioninterferences in the flame.NOTE 2Alkaline soluble arsenic can cause low bias on Au by FlameAA. Sampl
25、e Dilution, matrix spikes, or Method of Standard Additionsmay be needed.10. Apparatus10.1 Atomic Absorption Spectrometer, equipped with back-ground correction and capable of measuring gold at the242.8-nm wavelength using an air and acetylene flame over alinear range from 0.3 g/mL to 10.0 g/mL gold.1
26、1. Reagents and Materials11.1 Gold Calibration Solutions (0.5, 1.0, 2.0, 5.0, 10.0)g/mLIn a fume hood, pipette 10 mL of Gold StandardSolution A (11.2) into a 1-L volumetric flask containing 100mL of Sodium Cyanide-Sodium Hydroxide Solution (11.5).Dilute to volume and mix (10 g/mL).11.1.1 Pipette (5,
27、 10, 20, and 50) mL of the 10 g/mL goldcalibration solution into each of four 100-mLvolumetric flasks,respectively. Add 10 mL of Sodium Cyanide-Sodium Hydrox-ide Solution (11.5), dilute to volume, and mix.WARNINGReaction of acid or chlorine and cyanidesolutions releases toxic hydrogen cyanide or cya
28、nogen chloridegases. Prepare in a fume hood.11.2 Gold Standard Solution A (1 mL 1.0 g Au)Weigh1.000 g of gold metal (99.99 % minimum purity) and transferto a 1-L beaker in a fume hood. Add 200 mL of water, 80 mLof HCl, and 50 mL of HNO3(1 + 1). Boil gently to expel NOxfumes, cool, transfer to a 1-L
29、volumetric flask, dilute tovolume, and mix.11.2.1 A certified reference solution meeting these specifi-cations may also be used.NOTE 3Commercially prepared Gold Cyanide reference solutionsshould be preserved in NaCN.11.3 Reference SolutionDilute 100 mL of SodiumCyanide-Sodium Hydroxide Solution (11.
30、5), to 1 L with water.11.4 Sodium Cyanide.11.5 Sodium CyanideSodium Hydroxide SolutionDissolve 10 g of sodium hydroxide, then 10 g of sodiumcyanide in 1 L of water.WARNING The preparation, storage, use, and disposal ofsodium cyanide solutions require special care and attention.Avoid any possibility
31、of inhalation, ingestion, or skin contactwith the compound, its solution, or its vapors. Work only in awell-ventilated hood.11.6 Sodium Hydroxide.12. Preparation of Apparatus12.1 Follow the instrument manufacturers instructions toadjust the instrument for gold at 242.8 nm. Warm up the4Reagent Chemic
32、al, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see National Formulary, U.S. Pharma-ceutical Convention, Inc., (USPC), Rockville, MD.E1600 152instrument with background corr
33、ection applied in accordancewith the manufacturers instructions. With the gold hollowcathode lamp in position, energized and stabilized, adjust thewavelength to maximize the energy response of the 242.8-nmline. Light the burner, allow it to reach thermal equilibrium,and adjust the instrument to zero
34、 while aspirating water.12.2 The use of an air-acetylene, lean, blue flame andcaustic stabilized drain bottle is required.WARNINGReaction of acid and cyanide solutions in theburner chamber drain bottle may release toxic hydrogencyanide gas. Add an excess of sodium hydroxide to the drainbottle to mai
35、ntain the pH above eleven.12.3 Determine if the instrument precision is acceptable asfollows:12.3.1 Calibrate the instrument in accordance with themanufacturers instructions in absorbance. Set the absorbanceto zero while aspirating the reference solution.12.3.2 Aspirate the calibration solutions in
36、order of increas-ing concentration, and select a calibration solution in theabsorbance range from 0.2 absorbance units (AU) to 0.4 AU.12.3.3 Alternate readings on the selected calibration solu-tion and reference solution, and calculate the standard devia-tion of the readings on the selected calibrat
37、ion solution usingaccepted statistical methods. Measure the standard deviation inthis way at increased measurement integration times until arelatively constant value is achieved.12.3.4 If the standard deviation under these conditions isgreater than1%oftheaverage absorbance, determine thecause of the
38、 variability (for example, deposits in the burner orclogged capillary), and take corrective action.12.3.5 If the minimum requirements are not met, do not usethe instrument with this test method until the required stabilityis obtained.12.3.6 Collect all instrumental measurements for the testmethod us
39、ing the instrumental settings which gave the opti-mum precision of measurement on the selected calibrationsolution.12.4 Linearity of Instrument ResponseDetermine if theinstrument response is acceptable as follows:12.4.1 Record absorbance measurements for each of thecalibration solutions and the refe
40、rence solution, prior to deter-mining samples.12.4.2 Adequate instrument response is obtained if thedifference between the 5-g/mL calibration solution is suffi-cient to permit estimation of150 of the difference between them(0.1 g/mL).12.4.3 Adequate linearity is confirmed if the slope of thecalibrat
41、ion curve between the 5 g/mL and 10 g/mL calibra-tion solutions is at least 90 % of the slope between thereference solution and the 0.5-g/mL calibration solution.13. Calibration13.1 Calibrate the instrument in accordance with the manu-facturers instructions in absorbance or gold concentration.14. Pr
42、ocedure14.1 High-Precision Method:14.1.1 Adjust the instrument to zero with the referencesolution and measure the test sample solution to determine itsplace in the order of increasing concentration of the calibrationsolutions.14.1.2 Aspirate the test solution and the closely bracketingcalibration so
43、lutions in order of increasing absorbance orconcentration without intervening water aspirations. Repeatthree times and calculate the average absorbance or concentra-tion value for each of the three solutions.14.2 Linear Curve Method:14.2.1 Record the reference solution and calibration solu-tion read
44、ings before and after each test sample solution,selecting a different calibration solution after each test solution.14.2.2 Continue recording measurements until at least threereadings have been recorded for all test sample solutions and atleast one reading has been recorded for each calibrationsolut
45、ion. Calculate the average reading for each of the solu-tions.15. Calculation15.1 High-Precision MethodThe gold concentration of thetest solution is calculated as follows:Ct5AtCh2 C1!Ah2 A1!(1)where:Ct= concentration of gold in the test solution, g/mL,Ch= concentration of gold in the higher calibrat
46、ion solution,g/mL,C1= concentration of gold in the lower calibration solution,g/mL,At= average absorbance or concentration reading of the testsolution,Ah= average absorbance or concentration reading of thehigher calibration solution, andA1= average absorbance or concentration of the lowercalibration
47、 solution.15.2 Linear Curve MethodCalculate the gold concentra-tion of each test sample solution in micrograms per millilitreusing the graphical method, by simple linear regression, or byan equivalent computer method.15.3 Average the results of the duplicate test sample solu-tions and round the resu
48、lts to the nearest 0.1 g/mL inaccordance with Practice E29, unless an alternative roundingmethod is specified by the customer or applicable materialspecification.16. Precision and Bias16.1 PrecisionAn interlaboratory study was undertaken totest the precision of this test method in accordance withPra
49、ctice E1060 on six solutions in eight laboratories. Theresults from the study are summarized in Table 1. Since as fewas three laboratories returned results for some of the materials,E1600 153Practice E173 was used to estimate the precision. The base dataand statistics are documented.5NOTE 4Solutions 1 through 6 were analyzed by more laboratoriesthan Solutions 7 through 12.NOTE 5The reproducibility, R2, of Practice E173 corresponds to thereproducibility index, R, of Practice E1601 and the repeatability, R1, ofPractice E173 correspo
