Recovery of silver and gold from thiourea leach liquors by Di(2-Ethylhexyl) Dithiophosphoric acid
Résumé
This study deals with solvent extraction of gold and silver from thiourea leaching Au-Ag ore liquors as an alternative to the traditional process involving cyanide. The investigation of extraction mechanism of gold and silver from acidic thiourea solution had not been clearly established to date. The extraction behaviour of silver and gold using di(2-ethylhexyl)dithiophosphoric acid (D2EHDTPA) was studied. The effect of various parameters such as concentrations of metal, mineral acid, thiourea and extractant has been investigated. The extracted complexes have been identified through slope method analysis as AgX and AuX for silver and gold extraction, where HX denotes the extractant. Moreover, complete stripping were ensured with either (NH4)2S2O3 or a mixture of NH4SCN and H2SO4.