ASTM_E_2294_-_03_2013.pdf

Designation:E229403(Reapproved 2013)Standard Practice forProof Silver Corrections in Metal Bearing Ores,Concentrates,and Related Materials by Fire AssayGravimetry1This standard is issued under the fixed designation E2294;the number immediately following the designation indicates the year oforiginal adoption or,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 practice covers the determination of fire assaycorrection for silver,utilizing proof silver,ores,concentrates,and related metallurgical materials.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility 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.(See Test MethodsE1335,Practices E50,Guide E882,and ISO Guide 35:1989.)2.Referenced Documents2.1 ASTM Standards:2E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 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 MaterialsE882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE1335 Test Methods for Determination of Gold in Bullionby Fire Assay Cupellation Analysis2.2 Other Documents:3ISO Guide 35:1989 Certification of Reference Materials-General and Statistical PrinciplesISO 10378:1994 Copper Sulfide ConcentratesDetermina-tion of Gold and Silver ContentsFire Assay Gravimetricand Atomic Absorption Spectrometric Method3.Terminology3.1 DefinitionsFor definitions of terms used in thisPractice,refer to Terminology E135.4.Summary of Practice4.1 In the process of fire assay,silver losses occur.Proofsilver is carried through the assay fusion and cupellationprocedures to determine losses that can provide the fire assaysilvercorrectionvalues(seeTestMethodsE1335,ISO 10378:1994,Bugbee,4and Smith5).5.Significance and Use5.1 This practice is primarily intended to be used for thecorrection of silver loss in the fire assay process.Silver assaysare determined by fire assay for the purpose of metallurgicalexchange between seller and buyer.5.2 It is assumed that all who use this practice will betrained analysts capable of performing skillfully and safely.Itis expected that work will be performed in a properly equippedlaboratory under appropriate quality control practices such asthose described in Guide E882.6.Apparatus6.1 Analytical balanceCapable of weighing to 0.001 mg.1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals,Ores,and Related Materials and is the direct responsibility ofSubcommittee E01.02 on Ores,Concentrates,and Related Metallurgical Materials.Current edition approved Nov.1,2013.Published December 2013.Originallyapproved in 2003.Last previous edition approved in 2008 as E2294 03(2008)1.DOI:10.1520/E2294-03R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization(ISO),1,ch.dela Voie-Creuse,Case postale 56,CH-1211,Geneva 20,Switzerland,http:/www.iso.ch.4Bugbee,E.E.,A Textbook of Fire Assaying,Third Ed.,John Wiley and Sons,Inc.,Hoboken,NJ,1946.5Smith,E.A.,The Sampling and Assay of the Precious Metals,Second Ed.,Charles Griffin and Co.,Ltd.,1947.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 Assay furnaceCapable of temperatures up to 1100 C,accurate to 6 5 C.6.3 HammerBlacksmith type.6.4 Hammering blockFlat Steel plate.7.Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused 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.6Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Boraxsodium tetraborate(Na2B4O7)technicalgrade.7.3 Cupelsmagnesite(MgCO3)or bone ash.7.4 CruciblesStandard Fire Assay clay.7.5 Flourcommon baking grade.7.6 Lead Foil,99.99%purity,min(1 ug/g silver max).7.7 Litharge(PbO)technical gradeprecious metal free.7.8 Potassium Carbonate(K2CO3)technical grade.7.9 Silica Sand(SiO2)technical grade.7.10 Silver Metal,99.99%purity.7.11 Sodium Carbonate(Na2CO3)technical gr