Comparsion of bioleaching of copper sulphides by Acidithiobacillus ferrooxidans

Bioleaching of copper sulphides were investigated. The results show that the copper extraction from djurleite, bornite, covellite and chalcopyrite under the optimal conditions were 95.12, 84.5, 54.1, and 18.33%, respectively. A ranking for the bioleaching of copper sulfides was obtained: djurleite > bornite > covellite > chalcopyrite. A determination of the extent of adsorption of A. ferrooxidans on the surface of the minerals showed that the cell density of Acidithiobacillus ferrooxidans on djurleite was the highest. The order of adsorption on the copper sulphides was: djurleite > bornite > covellite > chalcopyrite. The results suggest a difference in affinity of bacteria for different copper sulphides. The higher the leaching rate of copper sulphides, the greater the density of bacteria absorbed on the surface of minerals. Key words: Bioleaching, copper sulphides, Acidithiobacillus ferrooxidans, cell density, copper extraction.