Biooxidation, gold

The biooxidation of refractory gold concentrates has been studied by several groups using stirred tank reactors and small-scale continuous systems, usually with T. ferrooxidans. Significant improvement in gold recovery has been achieved (6-8,26, 41, 69, 72,122). 

The Fairview Mine of Gencor in South Africa has operated a biooxidation plant since 1986. This accounts for about 40% of the pyrite/ arsenopyrite concentrate produced in the mine, taking about 12 tons per day. Gold recovery is greater than 95% after 4 days residence time. 

At the very least, biooxidation of refractory gold ores will be a valuable additional method for use with certain ore types. It is probable, however, that it will be of major significance. There is scope for the exploitation of this process in many parts of the world. It is understandable that gold producers are cautious at present. Established... 

F Acevedo, C Canales, JC Gentina. Biooxidation of an enargite-pyrite gold concentrate in aerated columns. In R Amils, A Ballester, eds. Biohydrometallurgy and the Environment Toward the Mining of the 21st Century, Part A. Amsterdam Elsevier, 1999, pp 301-308. 

This section briefly reviews the potential of living and dead plants and animals to accumulate gold from solution, and some of the processes involved - including biooxidation, dissolution, bioreduction, bacterial leaching, and biosorption. 

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