Solvent Extraction of Gold from Alkaline Aurocyanide Solutions by Cationic Surfactants

Solvent extraction of gold from alkaline aurocyanide solutions has more potential advantages over present zinc -dust cementation and carbon-adsorption procedures. This paper reviews some recent advances on the solvent extraction of gold recovery from the alkaline cyanide solutions. The extraction mechanism, extraction and stripping behaviors of the new surfactant/modifier gold extraction system are reported. Many parameters, such as different cationic surfactants, modifiers, diluents and inorganic salts in aqueous phase on the extraction of gold are investigated. An extracting species model of supramolecular structure based on the formation of hydrogen bonds between Au(CN)(2)(-) and modifier is proposed to explain the reaction mechanism of the new extraction system. The stripping gold from the loaded surfactant/modifier organic phase can be efficiently obtained by the methods of anion exchange, conversion followed by reduction and biphase electrowinning. The gold extraction approach suggested in the present paper provides a promising technique for gold recovery from alkaline aurocyanide solutions in industry.