Biooxidation Technology

The bio-oxidation technology was developed based on the processing of sulfides with the help of specialized bacteria, which feeds on iron sulfides, turning them into oxides, and can live in an aggressive chemical environment with the presence of arsenic, carbon, antimony and other substances.  The use of microorganisms allows for the decomposition of the hard gold bearing minerals, which cannot be processed in any other way.  As a result, gold extraction increases to 90%, compared to 30-40% using a method of direct cyanidation of sulfide ores. 

The full cycle of gold extraction from sulfide ores includes the following procedures:

• Primary ore is pulverized into particles not larger than 74 microns.
• Using flotation and the thickening of pulp, from 4 mln tons of ore, 120 thousand tons of gold-bearing sulfide concentrates are obtained.
• In specialized containers, the concentrate undergoes bio-oxidation with the help of bacteria.
• The product of bio-oxidation is processed in the hydro-metallurgical plant using a method of sorption cyanidation.
• From the gold-bearing solution, obtained from cyanidation, the metal is extracted using a method of electrolysis.
• The obtained gold is melted into gold bars. 

Bio-oxidation also differs with its environmentally friendly process.  It eliminates the release of gas and dust into the atmosphere, greatly decreasing the amount of waste.  As well, all of the dangerous and harmful substances are fully utilized and thus do not require special removal.