The solubility of gold in a water and cyanide solution was known by 1783 (Scheele), by Bagration in 1843 and Elsner in 1846 who recognized the necessity of oxygen in the process, (a method of exctraction by chlorination (Plattner) considered during 1848 proved uneconomical) this prior to the discovery of an economical method of treatment with potassium cyanide by J.S. MacArthur (with R. and, or, W. Forrest).
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