The basic principle of gold extraction by cyanidation

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Cyanide gold extraction method is one of the main methods for extracting gold from gold mines. The explanation of the mechanism of cyanide on the dissolution of gold is still inconsistent. Most people think that in the presence of oxygen in the cyanide solution of gold, a gold complex can be formed and dissolved. The basic reaction formula is:
4Au+8KCN+O 2 +2H 2 O=4KAu(CN) 2 +4KOH
It is generally believed that gold is cyanide dissolved in a two-step reaction:
2Au+4KCN+O 2 +2H 2 O=2Au(CN) 2 + H 2 O+2KOH
2Au+4KCN+ H 2 O 2 =2KAu(CN) 2 +2KOH
The surface of the gold is gradually dissolved in the surface and in the cyanide solution, and the concentration of oxygen in the solution is related to the dissolution rate of gold.

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