Bioleaching of low-grade copper sulfide ores by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

WANG Jun(王军)^{1, 2}, ZHU Shan(朱珊)^{1, 2}, ZHANG Yan-sheng(张雁生)^{1, 2}, ZHAO Hong-bo(赵红波)^{1, 2}, HU Ming-hao(胡明皓)^{1, 2}, YANG Cong-ren(杨聪仁)^{1, 2}, QIN Wen-qing(覃文庆)^{1, 2}, QIU Guan-zhou(邱冠周)^{1, 2}

(1. Key Laboratory of Biohydrometallurgy of Ministry of Education
(Central South University), Changsha 410083, China;
2. School of Minerals Processing & Bioengineering, Central South University, Changsha 410083, China)

Abstract:The grown conditions of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were investigated, and then experiments were conducted to research the bioleaching behaviors of crude ore of copper sulfide and hand-picked concentrates of chalcopyrite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The experimental results show that the bacteria grow best when the temperature is (30±1) °C and the pH value is 2.0. The bacteria concentration is 2.24×10⁷ mL^-1 in this condition. It is found that the copper extraction yield is affected by the inoculum size and the pulp density and the extraction yield increases as the inoculum size grows. The bioleaching rates reach their highest point in sulfide copper and chalcopyrite with a pulp density of 5% and 10%, respectively. Column flotation experiments of low-grade copper sulfide ores show that the bioleaching recovery reaches nearly 45% after 75 days.

Key words:biohydrometallurgy; chalcopyrite; Acidithiobacillus ferrooxidans; Acidithiobacillus thiooxidans; copper sulfide ore