Bioleaching of heazelwoodite by Thiobacillus spp

Thiobacillus ferrooxidans and Thiobacillus thiooxidans significantly enhanc es heazelwoodite (Ni3S2) dissolution. In pure cultures, heazelwoodite was m ore efficiently leached by T. ferrooxidans in the absence of alternative en ergy sources and in cultures supplemented with iron(II) and sulphur. In the other cultures, pure T. thiooxidans cultures reached greater extractions i n the presence of iron(III). Under all experimental conditions, mixed cultu res were more efficient than pure cultures. Nickel extraction in mixed cult ures can be analysed as a cooperation of the mechanisms involved in the pur e cultures of T. ferrooxidans and T. thiooxidans. (C) 2001 Elsevier Science Ltd. All rights Reserved.