THE INFLUENCE OF VARIOUS IONS IN THE BIOLEACHING OF METAL SULFIDES

The catalytic effect of various metallic ions (Hg2+, Co2+, Ag+, Bi3+ and Cu2+) in the bioleaching of a sphalerite concentrate and complex sulphide concentrate was studied. Bacteria of the type Thiobacillus ferro-oxidans adapted to sulphide concentrates were used. The cations studied increase the copper dissolution from complex sulphides, with Ag+ and Hg2+ prominent with an extraction efficiency of 90% and 72.5%, respectively, compared with a 26.5% recovery in the absence of a catalyst. The microbiological dissolution of the sphalerite improves considerably with the addition of Ag+ and Cu2+ as catalysts, with zinc dissolution of 90% Furthermore, it is shown that additional amounts of Cu2+ increase the percentage of metal leached. The influence of catalytic ions in electrochemical processes of dissolution of complex sulphides is discussed. © 1990.