Investigations on Bioleaching of Copper and Zinc Oxide Ores

Abstract

Although bioleaching is a well-known process for extraction of metals from sulfide ores investigated by many researchers, bioleaching of oxide ores has not been thoroughly studied. In this study, bioleaching of copper oxide ore and zinc oxide ore has been carried out by a heterotrophic bacterium, Pseudomonas aeruginosa. Organic reagents that are produced during bioleaching serve as a leaching agent and dissolve copper and zinc from these ores. In these experiments, the effect of parameters like bioleaching time, glucose percentage in the culture medium and solid/liquid ratio was optimized. Optimum conditions were found as glucose percentage of 6 (both copper and zinc), bioleaching time of 8 days for copper and 5 days for zinc, and the solid/liquid ratio of 1:100 for both zinc and copper. Under these conditions, 47% of copper and 41% of zinc were extracted. According to the obtained results, tolerance of this bacterium to copper is more than zinc tolerance.