Regular Article 

Concentrating Pt from a spent alumina carrier catalyst by a roast-leach process

Kunming Institute of Precious Metals, Sino-platinum Metals CO., Ltd, State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming, Yunnan 650106, PR China

^* e-mail: donghaigang0404@126.com

Received: 31 August 2018
Accepted: 16 October 2018

Abstract

A roast-leach process has been developed for concentrating platinum (Pt) from a spent Pt-Al₂O₃ catalyst. The effects of (NH₄)₂SO₄ to spent catalyst mass ratio, roasting temperature and roasting time on the Pt enrichment factors were investigated. The results showed that the optimized roasting conditions were (NH₄)₂SO₄ to spent catalyst mass ratio of 7.5, roasting temperature of 350 °C and roasting time of 5 h. The roasted product was mainly comprised of soluble NH₄Al(SO₄)₂ and Al₂(SO₄)₃ according to XRD analysis. The roasted product was leached in sulfuric acid to remove the soluble sulfates, and meanwhile Pt was kept in the residue. Under optimized conditions, a Pt concentrate with Pt content of 73.2% could be obtained from the spent catalyst with 0.27% Pt, and the corresponding Pt enrichment factor was more than 270.