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Platinum and rhodium recovery from scrapped automotive catalyst by oxidative acid chloride leaching

There is a great interest in the treatment of spent autocatalyst because, due to large amounts of PGM used by catalytic converters, the autocatalyst scrap is the largest and constantly growing source of PGM available for recycling. A hydrometallurgical method of PGM extraction from honeycomb type catalyst containing platinum (800-1200 ppm) and rhodium (50-60 ppm) using HCl-AlCl$ sb3$-HNO$ sb3$ or HCl-HNO$ sb3$ mixtures was studied. Experimental results of the leaches performed in a bench scale tubular reaction with recycled continuous flow of the leaching solution as well as 1000 cc stirred reactor are presented. The results suggest that Cl$ sp-$ single ion activity plays a decisive role in controlling the PGM dissolution. The extent of PGM recovery increased not by increasing HCl concentration to very high levels, but by keeping a relatively low total Cl$ sp-$ level (2.5 M) with a significant proportion present as AlCl$ sb3$. Rhodium extraction was always 5-10% lower than platinum, and it appears that increasing the AlCl$ sb3$/HCl ratio tends to increase rhodium recovery. High temperature (85-95$ sp circ$C) and an HNO$ sb3$ concentration around 3-3.5 M play very important roles in effectiveness of PGM extraction. The presented method of HCl-AlCl$ sb3$-HNO$ sb3$ tubular reactor leaching supplemented by solvent extraction (Kelex 100) of PGM from pregnant solution appears to be very attractive for small size (5-20 tonnes of catalyst/day) installations.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.60573
Date January 1991
CreatorsBoliński, Lech
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Engineering (Department of Mining and Metallurgical Engineering.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001258336, proquestno: AAIMM72173, Theses scanned by UMI/ProQuest.

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