Gold leaching with elemental sulfur in alkaline solutions under oxygen pressure
(Institute of Process Engineering,Chinese Academy of Sciences,
Beijing 100080, China)
Beijing 100080, China)
Abstract: A gold leaching process by using oxidation products of elemental sulfur in alkaline solutions was proposed and investigated. A gold concentrate and a residue from an arsenic refractory gold concentrate by acidic oxidation leaching were tested. The residue contains 16.3% elemental sulfur and no more elemental sulfur was added in tests. For the concentrate elemental sulfur was added before leaching tests. The leaching ratio of gold depends mainly on the initial equivalent ratio of elemental sulfur to hydroxyl ions, the consumption of oxygen and the reaction temperature in the process. Analysis of the experimental results shows that thiosulfate is the majority complexing reagent for gold in the process. Over 90% gold was leached from the residue and 82%-87% from the concentrate by using this process.
Key words: gold leaching; elemental sulfur; alkaline solution; oxygen pressure; and thiosulfate