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Why is oxygen added during pressure oxidation of gold sulfide concentrates?
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gold processing
The Tanami gold mine, Northern Territory, Australia.
In the context of gold processing, oxygen is added during the pressure oxidation of gold sulfide concentrates to destroy interfering sulfide minerals, such as pyrite, pyrrhotite, or arsenopyrite.1
Many gold-bearing ores are considered refractory because these sulfide minerals surround the gold particles, preventing the cyanide leach solution from accessing and dissolving the gold. By treating the mineral slurry with oxygen in high-pressure autoclaves, the sulfides are oxidized into a porous structure. This process effectively frees the gold from the mineral matrix, making it amenable to subsequent cyanidation for extraction.12