UNCORRECTED PROOF 2 Integratingpyrometallurgyandroboticsystemsengineering: 3 FullyautomatedfireassaylaboratoryforrapidPGEanalysis 4 K.S.McIntosh a ,D.Auer a ,K.R.Koch b ,J.J.Eksteen c, * 5 a Analytical Technology Research Department, Anglo Platinum Research Centre, P.O. Box 6540, Homestead, 1412, Republic of South Africa 6 b Department of Chemistry, University of Stellenbosch, Private Bag X1, Matieland 7602, Stellenbosch, Republic of South Africa 7 c Department of Process Engineering, University of Stellenbosch, Private Bag X1, Matieland 7602, Stellenbosch, Republic of South Africa Received25April2005;accepted17May2005 10 Abstract 11 Thepyrometallurgicalfireassaystillremainstheonlywidelyacceptedtechniquetoconcentrateplatinumgroupelements(PGE) 12 andgoldfromlowgradeoresandmetallurgicalintermediates.Thetraditionaltechniqueislabourintensivebatchprocesswhere 13 samplesarenotnecessarilyprocessedinafirst-in-firstout(FIFO)sequence.Togettothepointofmakingfireassaybasedinfor- 14 mationusefulforprocesscontrol,anumberofchallengeshadtobeaddressed.Theprocessofsamplepreparation,thewholefire 15 assayprocessandthefinalanalysisforthePGEhadtobeautomatedsothatthesampleswouldbeprocessedrapidlyandanalysedin 16 aFIFOsequence.Thisisparticularlydifficultduetotheamountofmaterialshandlinginconjunctionwiththehightemperatures 17 associatedwiththefireassay.Thefluxblendhadtobe‘‘designed’’oroptimisedforrapidfusion,insignificantmetalentrainmentand 18 effective(quantitative)transferofthePGEtotheleadcollectorphase.Thiscouldonlybedonethroughare-evaluationofthepyro- 19 metallurgicalprinciplesthatcontroltheslagchemistrysothatthefusionsequence,slagviscosityandslag–metalinterfacialtensions 20 are well controlled. The slag separation from lead alloy had to ensure that no slag contamination of metal occurred. This was 21 achieved through furnace re-design, and the development of a novel slag separator. Both stages (fusion and separation) had to 22 beintegratedanddesignedforrobotmanipulationandmaterialshandling.Moreover,thetraditionalcupellationstepoffireassay- 23 inghadtobeeliminated.Toachievethelaststageananalyticalmethodologyhadtobedevelopedtoautomaticallyweighthelead 24 anddeterminetheconcentrationoftheindividualPGEusingspark-OESbasedonthelead-PGEalloymatrix.Thewholeprocess, 25 automatedwitharoboticcarouselandmeetingalltherequiredobjectives,wassuccessfullyimplementedatAngloPlatinum.Turn- 26 aroundtimeonanalysiswasreducedfrom24hto60minfromthesubmissionofaslurrysampletothelaboratory.Theaccuracyof 27 thenewanalyticalmethodwasconfirmedusingcertifiedreferencematerials. 28 Ó 2005 Published by Elsevier Ltd. 29 Keywords: Pyrometallurgy;Non-ferrousmetallicores;Processcontrol;Reduction 30 31 1. Introduction 32 Theanalysisofplatinumgroupelements(PGE)ores 33 is complicated and time-consuming due to their low 34 grade, inhomogeneity and complex mineralogy. Bene- 35 faction of PGE-containing ores is done with flotation. 36 The PGE (in the case of the South African Merensky 37 reef)areassociatedwithsulphidemineralssuchaspent- 38 landiteandchalcopyritewhicharefloatedandrecovered 39 intheconcentrate,whilethemajorityoftheganguemin- 40 erals report to the flotation tails. The PGE concentra- 41 tion in these tails are in a much lower concentration 42 than in the feed or concentrate, making these precious 43 metal elements exceptionally difficult to quantitatively 44 analyseforintailingsstreams.Theproblemisthattra- 45 ditionalfireassaytechniquesforthePGEusealabori- 46 ous batch pyrometallurgical fusion followed by an 0892-6875/$-seefrontmatter Ó 2005PublishedbyElsevierLtd. doi:10.1016/j.mineng.2005.05.012 * Correspondingauthor.Tel.:+27823766055;fax:+27218082059. E-mail address: jeksteen@ing.sun.ac.za (J.J.Eksteen). Thisarticleisalsoavailableonlineat: www.elsevier.com/locate/mineng MineralsEngineeringxxx(2005)xxx–xxx MINE 2595 No. of Pages 13, DTD = 5.0.1 24 June 2005 Disk Used ARTICLE IN PRESS