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The oxidation of chalcocite was studied during sulphuric acid leaching, ferric sulphate leaching and bioleaching by measuring the pH, redox potential and leaching rate under various conditions. The results showed that oxidation was accelerated in the ferric sulphate and bacterial leaching processes. The highest Cu leaching rates were 42% in acid and 67% in ferric sulphate solutions within 20 days, while the bioleaching rate reached 90%., The oxidation of chalcocite was studied during sulphuric acid leaching, ferric sulphate leaching and bioleaching by measuring the pH, redox potential and leaching rate under various conditions. The results showed that oxidation was accelerated in the ferric sulphate and bacterial leaching processes. The highest Cu leaching rates were 42% in acid and 67% in ferric sulphate solutions within 20 days, while the bioleaching rate reached 90%.

The results are presented of commercial-scale dump bioleaching tests on secondary copper sulphide. The results showed that a leaching rate of 40% was achieved by dump bioleaching for 1 000 hours, and 75 % recovery over half a year. The dump bioleaching of secondary copper sulphide as chalcocite and covellite occurs in two stages. The leaching rate is faster in the first stage than in the second., The results are presented of commercial-scale dump bioleaching tests on secondary copper sulphide. The results showed that a leaching rate of 40% was achieved by dump bioleaching for 1 000 hours, and 75 % recovery over half a year. The dump bioleaching of secondary copper sulphide as chalcocite and covellite occurs in two stages. The leaching rate is faster in the first stage than in the second.

It was found that while acid leaching of pentlandite for 8 days only dissolved 12.48% of the nickel, bacterial leaching with Sulphobacillus thermosulphidooxidans extracted up to 44.41% and with the addition of yeast extract as much as 63.67%. The optimum leaching conditions were pH 2.0, 10% inoculation and 0.02% yeast extract., It was found that while acid leaching of pentlandite for 8 days only dissolved 12.48% of the nickel, bacterial leaching with Sulphobacillus thermosulphidooxidans extracted up to 44.41% and with the addition of yeast extract as much as 63.67%. The optimum leaching conditions were pH 2.0, 10% inoculation and 0.02% yeast extract.