Microbial oxidation of gold ores and gold bioleaching

KEYWORDS
Arsenopyrite oxidation • Bioleaching • Biohydrometallurgy • Pyrite oxidation • Refractory gold ores • Thiobacillus ferrooxidans
ABSTRACT

Abstract Much recent work in the field of biohydrometallurgy has been directed to the study of bio-oxidation of gold ores by acidophilic iron and sulfur oxidizing microorganisms. This work has been done worldwide and has resulted in several pilot plant and commercial scale operations for gold ore bio-oxidation. Bioleaching of gold by metabolic products of microorganisms has received less attention, but also offers opportunities for industrial application, especially if future regulations restrict the use of cyanide. This paper reviews recent progress in the use of microorganisms tooxidize the sulfidic matrix in refractory gold ores (bio-oxidation) and to solubilize elemental gold (bioleaching).