Bioleaching of complex polymetallic sulfide ores by mixed culture

WANG Jun(王军)^{1, 2}, ZHAO Hong-bo(赵红波)^{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 of China, Changsha 410083, China;
2. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)

Abstract:Bacterial leaching of single sulfide minerals and polymetallic sulfide ores was operated in shake flasks and small-scaled columns. The results show that bioleaching of jamesonite is not accessible, the iron extraction rate of pyrrhotite bioleaching reaches 98.2% after 26 d, and the zinc extraction rate of marmatite bioleaching reaches 92.3%, while the corresponding iron extraction reaches only 13.6% after 29 d. Pulp density has a significant effect on metal extraction of pyrrhotite and marmatite bioleaching. The corresponding metal extraction rate decreases with the increase of pulp density. For the polymetallic sulfide ores, zinc extraction of 97.1% is achieved after bioleaching in shake flasks for 10 d, while only 7.8% is obtained after bioleaching in small-scaled column. Analytical results of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) reveal that large amount of calcium sulfate is formed on the mineral surface.

Key words:polymetallic sulfide ores; jamesonite; marmatite; pyrrhotite; bioleaching