Abstract
Anilite oxidation was evaluated with two acidophilicthiobacillithat are important in bioleaching processes. The experiments were carried out in shake flasks in the absence and presence of energy sources such as 2 g/L powdered sulphur and 10 g/L Fe2+(as ferrous sulphate) at pH 2.0, 150 rpm, 35 °C. Tests showed that copper extraction in a mixed culture ofAcidithiobacillus ferrooxidansandAcidithiobacillus calduswas higher than in pure cultures with added sulphur in the presence of anilite. The effect of supplemental iron clearly improved Cu leaching by theA. ferrooxidansculture and the mixed culture. The oxidation of anilite byA. calduswas negligible and this bacterium seemed to have no ability to initiate anilite solubilization. On the other hand, an important potential ofA. caldusto leaching anilite was indicated. It can decrease pH of the medium and supply a suitable bioleaching environment.