1、Designation: D7728 11D7728 18Standard Guide forSelection of ASTM Analytical Methods for Implementation ofInternational Cyanide Management Code Guidance1This standard is issued under the fixed designation D7728; the number immediately following the designation indicates the year oforiginal adoption o
2、r, in the case 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 guide is applicable for the selection of appropriateASTM standard analyti
3、cal methods for metallurgical processing sitesto conform to International Cyanide Management Code guidance for the analysis of cyanide bearing solutions.1.2 The analytical methods in this practiceguide are recommended for the sampling preservation and analysis of total cyanide,available cyanide, wea
4、k acid dissociable cyanide, and free cyanide by Test Methods D2036, D4282, D4374, D6888, D6994,D7237, D7284, and D7511.The values stated in SI units are to be regarded as standard. No other units of measurement are includedin this standard.1.3 The values stated in SI units are to be regarded as stan
5、dard. No other units of measurement are included in this standard.1.4 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, health, and environmental practices and d
6、etermine the applicability ofregulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendatio
7、ns issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1293 Test Methods for pH of WaterD1976 Test Method for Elements in Water by Inductively-Coupled Pla
8、sma Atomic Emission SpectroscopyD2036 Test Methods for Cyanides in WaterD3694 Practices for Preparation of Sample Containers and for Preservation of Organic ConstituentsD3856 Guide for Management Systems in Laboratories Engaged in Analysis of WaterD4282 Test Method for Determination of Free Cyanide
9、in Water and Wastewater by MicrodiffusionD4374 Test Methods for Cyanides in WaterAutomated Methods for Total Cyanide, Weak Acid Dissociable Cyanide, andThiocyanate (Withdrawn 2012)3D4840 Guide for Sample Chain-of-Custody ProceduresD4841 Practice for Estimation of Holding Time for Water Samples Conta
10、ining Organic and Inorganic ConstituentsD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water AnalysisD6888 Test Method for Available Cyanides with Ligand Displacement and Flow Injection Analysis (FIA) Utilizing GasDiffusion Separation and Amperometric Detecti
11、onD6994 Test Method for Determination of Metal Cyanide Complexes in Wastewater, Surface Water, Groundwater and DrinkingWater Using Anion Exchange Chromatography with UV DetectionD6696 Guide for Understanding Cyanide Species1 This practiceguide is under the jurisdiction of ASTM Committee D19 on Water
12、 and is the direct responsibility of Subcommittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved Sept. 1, 2011July 15, 2018. Published September 2011July 2018. Originally approved in 2011. Last previous edition approved in 2011 as D7728 11. DOI: 10.1520/D7728-
13、11.10.1520/D7728-18.2 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 Summary page on the ASTM website.3 The last approved version of this histo
14、rical 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 may not be technically possible to adequately depict all changes accurately,
15、 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 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D72
16、37 Test Method for Free Cyanide and Aquatic Free Cyanide with Flow Injection Analysis (FIA) Utilizing Gas DiffusionSeparation and Amperometric DetectionD7284 Test Method for Total Cyanide in Water by Micro Distillation followed by Flow Injection Analysis with Gas DiffusionSeparation and Amperometric
17、 DetectionD7365 Practice for Sampling, Preservation and Mitigating Interferences in Water Samples for Analysis of CyanideD7511 Test Method for Total Cyanide by Segmented Flow Injection Analysis, In-Line Ultraviolet Digestion and AmperometricDetectionD7572 Guide for Recovery of Aqueous Cyanides by Ex
18、traction from Mine Rock and Soil2.2 ISO Standard:4ISO 17690:2015 Water QualityDetermination of Available Free Cyanide (pH 6) Using Flow Injection Analysis (FIA), GasDiffusion, and Amperometric Detection2.3 Other References:International Cyanide Management Code5National Water Quality Criteria for Cya
19、nide63. Terminology3.1 DefinitionsDefinitions: For definitions of terms used in this practice, refer to Terminology D1129 and Guide D6696.3.1.1 For definitions of terms used in this standard, refer to Terminology D1129 and Guide D6696.3.2 Definitions of Terms Specific to This Standard:3.2.1 refriger
20、ation, nstoring the sample between its freezing point and 6C.3.2.2 titratable cyanide, ncyanide measured by titration with silver nitrate to a rhodanine or silver electrode end point.3.2.3 weak and dissociable (WAD) cyanide, navailable cyanide and weak acid dissociable cyanides, excluding determinat
21、ionof iron-, gold-, and cobalt-cyanide complexes.3.2.3 titratable cyanide, ncyanide measured by titration with silver nitrate to a rhodanine or silver electrode end point.4. Summary of Guide4.1 Guidance is provided for selection of the appropriate analytical methods to determine cyanide for to apply
22、 to theInternational Cyanide Management Code guidance for analysis of cyanide in solution.5. Significance and Use5.1 This guide is intended as a means for selecting the proper methods for measuring cyanide to conform to the InternationalCyanide Management Code guidance related to the analysis of cya
23、nide bearing solutions. Cyanide is analyzed in process solutionsand in discharges in order to apply code guidance; however, improper sample collection and preservation can result in significantpositive or negative bias, potentially resulting in over reporting or under reporting cyanide releases into
24、 the environment.5.2 This guide contains comparative test methods that are intended for use in routine monitoring of cyanide. It is assumed thatall who use methods listed in this guide will be trained analysts capable of performing them skillfully and safely. It is expectedthat work will be performe
25、d in a properly equipped laboratory applying appropriate quality control practices such as thosedescribed in Guide D3856.6. Interferences6.1 Multiple interferences could affect the cyanide analytical results using methods enumerated in this guide. Refer to PracticeD7365 for proper handling of the so
26、lutions during sampling, mitigation of interferences and preservation prior to cyanide analysis.6.2 Unless otherwise specified, samples must be analyzed within 14 days; however, it is recommended to estimate the actualholding time for each new sample matrix as described in Practice D4841. Certain sa
27、mple matrices may require immediate analysisto avoid cyanide degradation due to interferences. A holding time study is required if there is evidence that cyanide degradationoccurs from interferences which would cause the holding time to be less than specified in this practiceguide or Practice D7365.
28、Potential interferences for cyanide analytical methods are shown in Table 1.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in this guide. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytic
29、al Reagents of the American Chemical Society, where4 Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,Switzerland, http:/www.iso.org.5 Available from International Cyanide Management Institute,
30、 1400 I Street, NW, Suite 550, Washington, DC 20005, https:/www.cyanidecode.org.6 Available from United States Environmental Protection Agency (EPA), William Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460,http:/www.epa.gov.D7728 182TABLE 1 Summary of CN Method Interference
31、s - adapted from ASTM D7365-09NOTE 1Adapted from Practice D7365 09.ANALYSIS STEP-Analysis Step COMPOUNDCompoundPROCESS/Process/MeasurementMEASUREMENTTECHNIQUETech-niqueDESCRIPTION OFDescription ofINTERFERENCEInterferenceSampling,Preservation,and StorageResidual chlorine,peroxide, or other oxi-dizers
32、N/A React with cyanide in solution rapidlydecreasing the cyanide concentration. Oxidizers can co-existwith cyanideSampling,Preservation,and StorageResidual chlorine,peroxide, or other oxi-dizersN/A React with cyanide in solution rapidlydecreasing the cyanide concentration. Oxidizers can co-existwith
33、 cyanide.Chloramines N/A React with sample at pH 10 increasing or decreasing thecyanide concentrationSulfide N/A Reacts with cyanide and oxygen to form thiocyanate decreasingthe cyanide concentration. Reaction is especially rapid if metalsulfides are present.Native sulfur (colloidalsulfur)N/A Very r
34、apid reaction to form thiocyanate. Decreases the cyanideconcentration.Sulfite N/A Reacts with cyanide at pH 10 decreasing the cyanide concentration.Reaction is almost immediate at pH.12Sulfite N/A Reacts with cyanide at pH 10 decreasing the cyanide concentration.Reaction is almost immediate at pH 12
35、.Light ( 50 mg S/L)Colorimetry Detected as cya-nide (at 50 mgS/L)GD-Amperometry Detected as Cya-nide (at 50 mgS/L)GD-Amperometry Detected as cya-nide (at 50 mgS/L)Thiocyanate Colorimetry Detected as CyanideThiocyanate Colorimetry Detected as cyanideFatty acids Titration Mask endpointSulfur dioxide C
36、olorimetry Increase chloramine T demand resulting in negative bias. The increaseddemand may not be noticed in automated colorimetric methodsSulfur dioxide Colorimetry Increase chloramine T demand resulting in negative bias. The increaseddemand may not be noticed in automated colorimetric methods.Car
37、bonates GD-Amperometry Negative bias at 1500 mg CO3/LCarbonates GD-Amperometry Negative bias at 1500 mg CO3/LD7728 1849.5 New, commercially cleaned, containers certified to be free of contamination are recommended for handling solutions;otherwise, wash containers with soap or biodegradable detergent
38、 if required, then dry by draining. For further information onsample containers, see Practices D3694.10. Procedure Selection10.1 Principles, Standards of Practice and Guidance Principles, Standards of Practice, and Guidance:10.1.1 The International Cyanide Management Code is organized into principle
39、s and standards of practice for implementationusing the guidance. Those principles, standards of practice and guidance related to metallurgical processing which require the useof analytical methods are discussed with identification of specific ASTM and ISO analytical methods that are appropriate for
40、implementing the guidance.10.2 Principle- OperationsPrincipleOperations:10.2.1 Manage cyanide process solutions and waste streams to protect human health and the environment.10.2.1.1 Standard of PracticeStandard of Practice Introduce management and operating systems to minimize cyanide use,thereby l
41、imiting concentrations of cyanide in mill tailings.10.2.1.2 GuidanceGuidance - While facilities must use the amount of cyanide determined to be metallurgically necessary forefficient precious metal extraction, operations should use on-line analysis, bottle roll or other test procedures to determine
42、theoptimal amount of cyanide, and should re-evaluate and adjust addition rates as necessary when changes in ore type or processingplant practices occur. A summary of ASTM and suitable ISO methods is given in Table 2.(1) Titratable cyanideCyanide Most Most metallurgical operations and laboratories re
43、ly on the silver nitrate titration toestimate the cyanide available for leaching gold, which is standardized in the Test Methods D2036, Titration Procedure.Measurement units are typically expressed as kg/tonne or lbs/st sodium cyanide, rather than cyanide, in order to track the usageof the commercia
44、lly available reagent. The solution pH should be adjusted to about 12 prior to titration to assure that the all ofthe free cyanide is present as the cyanide ion, rather than hydrogen cyanide.cyanide, which does not react with the silver titrant.(2) Other techniques that may be used to directly estim
45、ate the cyanide in process and laboratory solutions are ion selectiveelectrode (ISE), the ion chromatography (IC), and the free cyanide method in Test Method D7237. or ISO 17690. Users of thesetechniques will likely need to dilute process samples into the linear range of the method and need to take
46、into account any shiftsin equilibrium of metal cyanide complexes resulting from dilution in interpreting the results. Ion Chromatography and IonTABLE 2 Summary of ASTM CN MethodsAnalyte Method CommentsTitratable CN D2036 (no distillation) Applicable to leachate solutions when Cu 1mg/L. Adjust to pH
47、12D6888 (no ligands) Preferred method for leachate solutions when Cu 50 mg/L Measures Cu, Ni, and Hg complexesFree Cyanide D7237 Preferred methodD4282 Alternate method, provided equivalent results are demonstratedWAD Cyanide D6888 Preferred method, quantitative recovery of Zn, Cd, Cu, Ag, Ni, and Hg
48、 complexesD2036 amenable Alternate method, provided equivalent results are demonstratedD2036 WAD Alternate method, provided equivalent results are demonstratedD4374 WAD Alternate method, provided equivalent results are demonstratedTotal Cyanide D7511 Preferred methodD2036 (with distillation) Alterna
49、te method, provided equivalent results can be demonstratedD4374 (UV 290nm) Alternate method, provided equivalent results can be demonstratedD7284 Alternate method, provided equivalent results can be demonstratedTABLE 2 Summary of ASTM CN MethodsAnalyte Method CommentsTitratable CN D2036 (no distillation) Applicable to leachate solutions when Cu 1mg/L. Adjust to pH 12D6888 (no ligands) Preferred method for leachate solutions when Cu 50 mg/L Measures Cu, and some Ni, and Hg complexes,on-line instrument availableFree Cyanide D7237 Preferred methodISO 17690 Pre
