Optimizing conditions for bacterial leaching of copper from discarded mines

The effect of process parameters (pH, pulp density, inoculum volume, ferrous content, particle size) on the rate of coppersolubilization was analyzed respectively through bioleaching tests with mixed bacteria in shake flasks. These results show that the optimal process parameters are: pH, 1.50-1.80; pulp density, 5wt%; inoculum volume, 10vol%; ferrous content, 2g·L^-1; particle size,<0.076 mm. Furthermore, when the pH value is below 1.50 in leaching solution, the iron precipitated can be reduced to a great extent,but it shows low bacterial activity at this pH. Finally, it is emphasized that the optimal parameters are also determined by economical benefit.