Acidithiobacillus Ferrooxidans Applied for the Beneficiation of Platinum Group Metals-Bearing Base Metal Sulphides

Platinum group metals (PGMs) high-grade ore tonnage from Merensky reef keeps on depreciating forcing the metallurgical industry to explore beneficiating PGMs from upper group 2 (UG2) ore which has up to 60% content of chromite and from secondary sources. The PGMs are naturally associated with base metal sulphides and the efficacy of the PGMs extraction processes is dependent on the processing of PGMs-bearing base metal sulphides. These processes include concentrating PGMs-bearing base metal sulphides through flotation, oxidation, etc. prior the metal extraction processes. The evolving mineralogy of PGMs ores has necessitated the use of multiple reagents to enhance the efficiency of the concentration process. This has led to an increased amount of inor-ganic chemicals disposal to the environment and the processing of PGMs to be less economic. Bio-technology has been investigated as a potential low cost, ecologically safe substitute for many current minerals processing methods. The metabolites produced by microorganisms have been used for many years with great success in the leaching and flotation of metals from medium and low-grade sulphide minerals. The possible application of microorganism mainly Acidithiobacillus ferrooxidans (A. ferrooxidans) in the metallurgical processing of PGMs-bearing base metal sulphides is systematically reviewed in this paper. The main emphasis is on the use of A. ferrooxidans in bio-oxidation and bioleaching, as well as their potential to substitute inorganic reagents in the flo-tation of PGMs-bearing base metal sulphides from primary and secondary sources