| In this study, the effectiveness of sulfuric acid, nitric acid and hydrogen peroxide pressure oxidation and roasting on the cyanide extractability of gold from a double-refractory concentrate is presented. While over 90% of the sulfide content could be oxidized by acid pretreatment, only 65% was achieved by peroxide pressure oxidation. Carbon oxidation by both acid and peroxide pretreatments were less than 15%. Although the peroxide pretreatment resulted in much lower sulfur and carbon oxidation, it gave residues with decreased levels of preg-robbing activities and higher gold recoveries (83%) during subsequent cyanidation. The residual carbonaceous materials were found to be very active in terms of preg-robbing even after H;It was found that only roasting pretreatment was capable of completely oxidizing the carbon and sulfide, leading to high gold extraction. (Abstract shortened by UMI.). |
