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Why is oxygen needed during the cyanidation of gold?
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gold processing
The Tanami gold mine, Northern Territory, Australia.
In the process of cyanidation, oxygen is essential because it acts as the necessary oxidant to facilitate the dissolution of metallic gold.
When gold is exposed to an aqueous solution of sodium cyanide, it does not dissolve on its own. The presence of atmospheric oxygen allows for the chemical reactionâknown as the Elsner reactionâto occur, which oxidizes the gold and converts it into a soluble form, specifically sodium cyanoaurite. Without this oxidation step, the cyanide solution would be unable to effectively extract the gold from the ore.1