Pressure Leaching Kinetics of Multimetallic Sulphide Concentrates in H2SO4 + O2 Solution

Abstract

A multimetallic sulphide concentrate containing sphalerite, galena, chalcopyrite and silver in the matrix of pyrite was decomposed at elevated temperature and oxygen pressures in dilute sulphuric acid solutions for sufficient residence time to yield 95% of the zinc in the pregnant solution while most of the lead and silver remained in the residue together with most of the pyrite. The selective leaching process appeared to follow the diffusion controlled mechanism. The effects of concentration of the leachant, temperature and time of leaching, particle size, oxygen pressure and agitation on the leaching process were investigated. Results indicate the prospect of extracting not only all the metals but also appreciable amounts of elemental sulphur under optimized experimental conditions.