Gold Recovery from Quartz Vein−Type Gold Deposits Using Thiosulfate Leaching and Resin Adsorption

To address the issues of high sodium thiosulfate consumption and the competitive adsorption of Au⁺ and Cu²⁺ on resin leading to difficulty in selective gold adsorption during the thiosulfate leaching−adsorption process of a quartz vein−type gold ore, this study innovatively proposed adding chemical agents to control the oxidative decomposition of sodium thiosulfate during leaching and screening suitable adsorption resins based on their adsorption capacity and selectivity. On the basis of the mineralogical characteristics of the gold ore, the leaching behavior of gold in the presence of additives such as sodium carboxymethyl cellulose, sodium humate, and sodium chloride was systematically investigated. The study also examined the adsorption of gold and copper from the leachate by different types of ion−exchange resins and their impact on the actual ore leaching and adsorption process. The results indicate that under optimal leaching conditions, ammonia, ammonium sulfate, sodium thiosulfate, copper sulfate, and sodium humate additions of 217.60, 105.71, 202.38, 12.77, and 0.24 kg/t, respectively, with a leaching temperature of 35 °C and a duration of 8 h, the gold leaching rate reaches 95.87%, while sodium thiosulfate consumption decreases by 21.77% compared to the case without additives. Sodium humate and 711 resin are identified as the optimal additive and adsorption resin, respectively. The 711 resin exhibits a saturated gold loading capacity of 8.47 kg/t, with a gold−to−copper selectivity coefficient reaching 127.56. Under optimal adsorption conditions of a sodium humate addition of 0.24 kg/t, a resin 711 dosage of 30 g/L, and an adsorption time of 2 h, the simultaneous leaching−adsorption process applied to the gold ore resulted in a gold grade of 0.12 g/t in the leaching residue, a gold leaching rate of 94.50%, and adsorption rates of 94.76% for gold and 20.47% for copper, with sodium thiosulfate consumption reduces to only 30.04 kg/t. Thus, successfully achieved the efficient leaching and selective adsorption recovery of gold from the ore.