ASTM_E_1335_-_08.pdf

Designation:E133508Standard Test Methods forDetermination of Gold in Bullion by Fire Assay CupellationAnalysis1This standard is issued under the fixed designation E1335;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 These test methods cover cupellation analysis of bullionhaving chemical compositions within the following limits:ElementConcentration Range,%Gold0.5 to 4.0 and 20.0 to 99.8Silver1.0 to 99.5Total gold plus silver75.0 to 100.01.2 These test methods appear in the following order:Sections20.0%99.0%gold10-170.5%4.0%gold18-2398.9%99.8%gold24-301.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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.For specific safetyhazards,see Section 8.2.Referenced Documents2.1 ASTM Standards:2B562 Specification for Refined GoldE50 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 Analysis of Metals(Withdrawn1998)3E1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3.Terminology3.1 DefinitionsFor definitions of terms used in these testmethods,refer to Terminology E135.3.2 Definitions of Terms Specific to This Standard:3.2.1 anneala thermal treatment to change the propertiesor grain structure of the product.3.2.2 cupela small,shallow,porous cup,usually made ofbone ash or from magnesium oxide.3.2.3 cupellationan oxidizing fusion of lead,sample basemetals and gold,and silver in a cupel.The lead is oxidized tolitharge(PbO);other base metals which may be present,suchas copper and tin,are oxidized as well.The oxidized metals areabsorbed into the cupel,leaving a gold and silver dor bead onthe cupel surface.3.2.4 dor beada gold and silver alloy bead which resultsfrom cupellation.3.2.5 inquartationthe addition of silver to an assay sampleto enable parting.3.2.6 partthe separation of silver from gold by selectivelydissolving the silver in acid,usually nitric acid(HNO3).3.2.7 proofa synthetic standard having a compositionsimilar to the test sample.3.2.8 proof correctionanalyzing the proof concurrentlywith the test sample and using the results to correct the finalassay.4.Significance and Use4.1 These test methods are intended for the determination ofthe gold content of gold and silver bullion.It is assumed that allwho use these test methods are trained assayers capable ofperforming common fire assay procedures skillfully and safely.It is expected that work will be performed in a properlyequipped laboratory.1These test methods are under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals,Ores,and Related Materials and are the directresponsibility of Subcommittee E01.05 on Cu,Pb,Zn,Cd,Sn,Be,Precious Metals,their Alloys,and Related Metals.Current edition approved Nov.1,2008.Published December 2008.Originallyapproved in 1990.Last previous edition approved in 2004 as E1335 041.DOI:10.1520/E1335-08.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Interferences5.1 If the bullion contains any of the following elements inexcess of the concentrations shown,the accuracy and precisionrequirements of these test methods may not be achieved.ElementMaximum Level,%Arsenic2.0Antimony2.0Bismuth2.0Iron2.0Nickel2.0Platinum group,total(Ir,Os,Pd,Pt,Rh,Ru)0.01Selenium2.0Tellurium2.0Thallium2.0Tungsten0.5Zinc5.06.Apparatus6.1 Assay FurnaceCapable of temperatures up to1100 C,accurate to 6 10 C,with draft controls and fumehood.6.2 Hammer.6.3 Hammering Block.6.4 Rolling Mill.6.5 Analytical Balance.6.5.1 For Test Methods A and B,capable of weighing to0.01 mg.6.5.2 For Test Method C,capable of weighing to 0.002 mg.6.6 Parting BasketPlatinum basket or porcelain goochcrucibles in stainless steel basket/vessel.6.6.1 Gooch Porcelain Crucible13 mL capacity,bottominside diameter(ID)18 mn,top ID 29 mn.6.6.2 Stainless Steel Basket316 stainless steel.7.Reagents47.1 Copper Metal,99.9%purity,minimum;0.