History of Cyanide Use in Gold Mining

Alkaline chlorination of wastewaters is one of the more widely used methods of treating cyanide wastes. In this process, cyanogen chloride (CNCl) is formed, which is hydrolyzed to the cyanate (CNO ) at alkaline pH. If free chlorine is present, CNO can be further oxidized. The use of sulfur dioxide in a high dissolved oxygen environment with a copper catalyst reportedly reduces total cyanide 

With regard to cyanide use and toxicity on the recovery of gold and other precious metals, most authorities currently agree on nine points  

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