Gold Extraction Method by Two Step Bacterial Oxidation

This invention involves in a method of two step bacterial oxidation of refractory gold concentrates using bacteria. Its process procedures includes: preparation of bacterial solution, milling of gold flotation concentrate, condensation and agent removal, pulp making for first oxidation, first bacterial oxidation, separation of solid and liquid, pulp making for secondary oxidation, secondary bacterial oxidation, condensation, washing, pressure filteration, and conventional gold extraction. The bacterium used in this technique is ferrous thiobacilli. Since two step bacterial oxidation is used in process, it eliminates these inactive or died bacteria from the first oxidation, which increases the capacity rate of oxidation and, at the same time, increases the leaching recovery of gold, especially for the gold concentrates with high contents of aresenic and sulphur.
Patent number：01100058.9