Development of Gold and Silver Extraction Technology from Ores and Intermediate Products Containing Mercury

Abstract

For a long time the ores of placer deposits were processed using amalgamation method, and this resulted in contamination of mine sites and products of treatment with mercury. Adverse effects of mercury manifested themselves at different stages of the precious metals extraction process using cyanide technology. With the aim of improving the process the physico-chemical behaviour of mercury during cyanidation, sorption and desorption using activated carbons and ion exchange resins, electrowinning and cementation was studied. The studies came up with a set of conditions of the cyanidation process which prevented mercury from passing into a solution or brought its solubilization up to 80%. Studies on the selective removal of mercury from cyanide solutions using different chemical methods were carried out. A settling reagent for cyanide solutions causing almost complete precipitation of mercury was found. Tests on gold and silver extraction from mercury-free cyanide solutions by sorption, electrowinning and ce...