Gold Extraction from an Oxide Ore by Thiourea Leaching with Hydrogen Peroxide as an Oxidant

Abstract

In this study, the effects of thiourea (CH4N2S) on the efficiency of gold dissolution were investigated for the extraction of gold from an oxide gold ore of the eastern Anatolia region, Turkey. In the thiourea leaching experiments; several parameters such as particle size (-75, -53, and -38 mu m), leaching time (30, 60, 120, 180, and 240 min), thiourea concentration (0.1, 0.25, 0.5, 1, and 1.5 mol/dm(3)), pH (1, 2, 3, 4, and 5), and pulp temperature (20, 40, 60, and 80 degrees C) were examined using hydrogen peroxide (H2O2) as an oxidant. The results from these experiments showed that the highest efficiency for Au dissolution was obtained as 91.94% at -38 mu m particle size, 120 min of leaching time, 1 mol/dm(3) thiourea concentration, pH 1, and 80 degrees C pulp temperature. The results obtained from this study indicated that the thiourea leaching could be evaluated as an alternative method for the dissolution of gold from oxide gold ores.