Bioleaching of low grade copper ores from Yongping by the mixed bacteria

Muqing Qiu, Shuiying Xiong and

Abstract

The effect of process parameters (pH, pulp density, inoculum volume of the nutrient medium, silver content) on the rate of copper solubilization was analyzed respectively through silver-catalyzed bioleaching experiments with microorganisms in shake flasks. These results show that the optimal process parameters are: pulp density, 2.5 wt%; silver content, 10mg/L; pH, 1.50-1.80; inoculum volume of the nutrient medium, 40vol%. Furthermore, the addition of the silver could catalyze the process of bioleaching, and high silver concentrations would be harmful to the bacterial activity and the copper extraction. pH and inoculum volume of the nutrient medium had a marked influence on the copper extraction and iron extraction. The bioleaching of the low-grade copper ore requires a minimum amount of the nutrient medium to obtain the maximal efficiency