What is Bioleaching?

Although the terms bioleaching and biooxidation are often used interchangeably, there are distinct technical differences between these process technologies. Bioleaching refers to the use of bacteria, principally Thiobacillus ferrooxidans, Leptospirillum ferrooxidans and thermophilic species of Sulfobacillus, Acidianus and Sulfolobus, to leach a metal of value such as copper, zinc, uranium, nickel and cobalt from a sulphide mineral. Bioleaching places the metal values of interest in the solution phase during oxidation. These solutions are handled for maximum metal recovery and the solid residue is discarded. Mineral biooxidation refers to a pretreatment process that uses the same bacteria as bioleaching to catalyze the degradation of mineral sulphides, usually pyrite or arsenopyrite, which host or occlude gold, silver or both. Biooxidation leaves the metal values in the solid phase and the solution is discarded.

Authors: Nick Holder, Tracey Stanek, Todd Harvey