Biotechnology for metal extraction, mineral beneficiation and environmental control

Abstract

With the rapid depletion of high grade ores and concerns about environmental degradation, the necessity for utilisation of lean grade mineral resources have become all the more urgent. With the advent of bioleaching since the early 1960's, possibilities of metal extraction in an environment-friendly fashion have emerged. As of now three metals namely copper, uranium and gold are commercially produced around the world using biooxidation in the presence of Acidithiobacillus ferrooxidans. Bioleaching of base metal concentrates such as those containing copper, zinc and nickel has also been proved to be commercially viable during this decade. Bioreactor technology using thermophilic bacteria holds the key for the successful and efficient bioleaching of chalcopyrite, sphalerite and pentlandite concentrates. Microorganisms find use in environmental control and mineral beneficiation as well. Microbially-induced mineral flotation and flocculation have been proved to very cost-effective and environment-friendly. In this paper, biotechnology as applied to metal extraction, mineral beneficiation and environmental control is illustrated.