Eco-Friendly and Low-Energy Innovative Scheme for Green Gold Extraction: Thermodynamics, Kinetics, and Application of Self-Generating Thiosulfate at Atmospheric Pressure

Abstract

The self-generation of thiosulfate from sulfurbearing minerals at atmospheric pressure can address its high consumption bottleneck. However, the stability factors, generation model of thiosulfate, and its systematic application in gold extraction are still elusive. Herein, it was elucidated that the adverse effects of temperature elevation on shortening the thermodynamic stability range of thiosulfate can be overcome by increasing the alkalinity of the solution. And the generation kinetics fitting results indicate that the oxidation process conforms to a shrinking core model under the control of surface chemical reactions (E a = 40.67 kJ/mol), which contributed to the precise regulation of the thiosulfate generation process. Further, a gold extraction rate of 86.02% was obtained by utilizing self-generated thiosulfate, and copper and gold were efficiently recovered from the desorbed pregnant solution (the desorption rates of copper and gold were 99.41% and 98.63%, respectively), demonstrating that self-generated thiosulfate can completely replace conventional chemically pure thiosulfate. This successful research has perfected the theoretical and technical framework for self-generating thiosulfate from sulfur-containing minerals, providing valuable insights and technical support for successfully applying this technology in refractory sulfide gold ore resources.