Bioprocessing for enhanced gold recovery

Abstract

The use of autotrophic and heterotrophic microorganisms in the solublisation of gold from refractory sulphides and oxide ores is discussed. Basic microbiological characteristics of the leaching bacteria are outlined. Reaction mechanisms in the biooxidation of gold-bearing arscnopyrite and pyrite an: illustrated with special reference of Thiobacillus ferrooxidans. Biological and engineering factors influencing biooxidation for the liberation of gold are critically examined. Available reactor designs as welt as pilot-plant operations are brought out. The utility of heterotrophs in the direct leaching of gold is also evaluated. The role of biosorption in the recovery of precious metals from solutions and in environmental control is also examined. The potential of biomineral technology for processing gold-bearing ores and concentrates in the Indian context is highlighted.