Selective leaching of bismuth from mechanically activated concentrate

Abstract

The hydrometallurgical processing of complex concentrates represents an ecologically attractive alternative with respect to classical pyrometallurgical technologies. In this study, the aim is to investigate bismuth recovery from fine lead sulphide concentrate by using hydrochloric acid, sulphuric acid with sodium chloride and sodium thiosulphate. Experimental studies were carried out on the sulphide sample from Atacocha (Peru) deposit, which contains 1·3% bismuth. Only 38% of bismuth was recovered from the ‘as received’ concentrate in 60 min. Mechanical activation proved to be an appropriate pretreatment for this concentrate before extraction of bismuth into solutions. The physicochemical changes in the complex sulphide concentrate due to mechanical activation have an influence on the increase in the recovery of bismuth for subsequently thiosulphate leaching. It was possible to achieve ∼99% bismuth recovery within 3 min for a sample mechanically activated. Thiosulphate leaching is an advantageous leaching reagent for selective and notable kinetic.