Comparative study of chalcopyrite bioleaching in the presence of the ion Ag(I) with acidophilic bacteria

Abstract

The bioleaching of metallic sulphides is carried out by acidophilic bacteria such as Thiobacillus ferrooxidans and Leptospirillum terrooxidans, among other, through the (re)generation of ions Fe(III) and the sulphide oxidation. Previous studies have demonstrated the catalytic effect of the silver ion on the chalcopyrite bioleaching by Fe(III) in acid media. In this work the bioleaching of chalcopyrite concentrates was studied using strains of mesophilic and moderate thermophilic bacteria in presence of silver ions. In the case of mesophilic microorganisms the addition of small quantities of silver in the solution increases the copper extraction. In presence of moderate thermophilic microorganisms the increase in the leaching temperature accelerates the kinetics of chalcopyrite oxidation. The results obtained in both tests are presented.