Quantitative-Determination-of-Silver-Content-Using-Fire-Assay-New-proposal-AR25.pdf

1、QUANTITATIVE DETERMINATION OF SILVER CONTENT USING FIRE ASSAY:NEW PROPOSAL FOR ISO TC174 Simone MarsanLBMA Assaying&Refining Conference17th March 20252ANALYTICAL METHODS FOR DETERMINING SILVER PURITY:A WIDE RANGE OF CHOICESpectrometric AnalysisMetallurgical AnalysisVolumetric AnalysisCupellation(Fir

2、e Assay)Inductively Coupled Plasma Mass Spectrometry(ICP-MS)Inductively Coupled Plasma Optical EmissionSpectrometry(ICP-OES)Spark-Optical Emission Spectrometry(Spark-OES/LA-Spark)X-Ray Fluorescence Spectrometry(WDXRF/EDXRF)Potentiometric TitrationTitration with indicator:Gay-Lussac,Mohr,Volhard,Faja

3、ns.3MethodSampleProsConsRangeCostCupellation method(fireassay)solidHistorical and well-established methodDestructive,affected by the presence of other metals400-999(proposed)Low(if Au by fire assay is in place)X-Ray FluorescenceSpectrometry(EDXRF)solidNon-destructive,quick,easy to useLimited sensiti

4、vity for light elements,expensive for equipmentIntended for jewellery products(800-958)Medium/HISpark-OESsolidHigh sensitivity,easy to useExpensive,requires sample preparation999HIfor trace determinationICP-OESliquidExtremely sensitive,trace detectionExpensive,complex to operate999 HIfor trace deter

5、minationVolumetric MethodsliquidGood precision,relatively simpleRequires specific reagents,less suitable for complex samples,affected by the presence of other metals100 to 999Quite low4ALTERNATIVES TO SILVER ASSAYING BY CUPELLATIONCan we still consider Silver assaying by cuppelation an up to date me

6、thod?Yes but repeatability&uncertainty must be evaluated very carefully!Overlapping area?MethodStandard05100 200 400 800 925 958 999(1000)Fire assayV ariousTitrationISO 11427:2024ED-X RFISO 23345:2021ICP-OESISO 15096:2020Spark-OESISO 18214:2024Ag5The determination of Ag content via fire assay is a t