FEASIBILITY OF A THIOBACILLUS-FERROOXIDANS BACTERIAL LEACHING OF A CHEMICALLY PRELEACHED CHALCOPYRITE

In this paper the changes of the chalcopyrite, chemically preleached with the solution of iron (III) sulfate, are described and the possibilities of its subsequent leaching by the bacteria Thiobacillus ferrooxidans are examined. It has been found that a layer of elemental sulfur is created on the surface of samples and its amount linearly increases with time during chemical preleaching. At the same time, the volume of chalcopyrite changes, which is characterized by a decrease in values of the lattice parameters. The rate of bacterial leaching of the chemically preleached chalcopyrite is a function of the specific surface area of the preleached samples and decreases with increasing amount of the sulphur created on the surface. The presented results suggest that it would be feasible to combine chemical and bacterial leaching at least in closed-device experiments to improve or to increase total copper recovery.