Amenability of Cambodian chalcopyrite concentrate to bioextraction copper by iron oxidizing consortium

Abstract

A report issued by the Department of Mineral Resources, Cambodia, indicated significant metal extraction potential in Cambodia, as the mineral resources available in the country are still not completely mapped and explored for production of valuable metals and minerals. So, reports are not available on bioleaching studies with those minerals. In the present work, bioleaching amenability study for extraction of copper from a Cambodian chalcopyrite concentrate is reported. The concentrate showed the presence of 31.69% w/w copper. In a shake flask bioleaching study, the consortium used consist of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and heterotrophic organisms. The activation of the consortium required five sequential transfers that resulted in 2.91 fold faster rate in ferrous oxidation by the consortium. Initial system pH of 1.8, showed better activity as compared to pH 2 and 2.5. It showed 61.34% copper extraction after 24 days of incubation. The addition of 5% w/v concentrate at 48 h of inoculation showed the highest copper extraction of 97.12% as compared to pulp addition immediately after inoculation. This preliminary bioleaching study suggests that the concentrate is amenable to bioextraction as maximum 1.5 g/L copper was extracted in the study. The leaching rates can be further improved with detail optimization of the process and scale-up studies.