INVESTIGATION OF THE OPTIMAL TECHNOLOGY FOR COPPER LEACHING FROM OLD FLOTATION TAILINGS OF THE COPPER MINE BOR (SERBIA)

This work aimed to investigate optimal leaching technology for copper extraction from old flotation tailings of the Copper Mine Bor. The leaching degree of copper after leaching with sulphuric acid at 80 degrees C was 50%, the maximal leaching degree was achieved after 30 minutes. Then, old flotation tailings were leached with adapted moderately thermophilic acidophilic bacteria in a bioreactor at 40 degrees C. Maximal leaching degree of 84% was achieved after nine days of the experiment. The third leaching experiment was conducted with biogenic lixiviant obtained by bacterial oxidation of the ferrous iron (concentration of Fe3+ 1300 mgL(-1), pH 2.14). Biogenic lixiviant with ferric sulphate was then used in the leaching experiment at 80 degrees C. Maximal leaching degree was 78%, and it was achieved after five minutes. Results of the leaching experiments show that the most efficient technology for copper recovery from the old flotation tailings of the Copper Mine Bor was leaching with biogenic lixiviant.