Novel insights into the modification of chalcopyrite and pyrite by Thiobacillus ferrooxidans: Surface phase and hydrophilicity studies.

Thiobacillus ferrooxidans (T. ferrooxidans) was used as a clean biosurfactant to modify chalcopyrite and pyrite to substitute lime during copper-sulfur separation under weakly alkaline conditions. When chalcopyrite was treated with T. ferrooxidans, the surface of chalcopyrite with Cu-S compounds and S0 as the main oxidation products exhibited better hydrophobicity than pyrite with hydroxyl iron and sulfate as the main passivation products. The phase identification results of the mineral surface revealed the differences in the modification of T. ferrooxidans. T. ferrooxidans facilitated the oxidation on the chalcopyrite surface, thus generating Cu-S compounds that provided more effective sites for collector adsorption. The generation of Cu-S compounds further intensified the adsorption difference of xanthate on the surfaces between chalcopyrite and pyrite, leading to hydrophobicity on the surface of chalcopyrite and hydrophilicity on the surface of pyrite. This study provides new insight into the application of biosurfactants in green mineral processing.