Leaching of Guizhou Carlin-type gold mine with sodium thiosulfate at room temperature

The leaching of gold from Carlin type gold deposits in Guizhou province with sodium thiosulfate was studied. The effects of Na₂S₂O₃ concentration, ethylenediamine concentration, Cu²⁺ concentration, Na₂SO₃ concentration and solution pH value on the gold leaching rate were investigated. The results showed that Na₂S₂O₃ concentration was 0.35 mol/L, ethylenediamine concentration was 0.1 mol/L, Cu²⁺ concentration was 0.075 mol/L, Na₂SO₃ concentration was 0.1 mol/L, the pH value was 9.5, and the best leaching condition was at room temperature (25 ℃) for 4 h with the leaching rate of gold up to 75.56%. The results of the three optimization and expansion tests and the XRD pattern analysis of the ore samples before and after leaching all prove that the thiosulfate has certain leaching effect on the Carlin type gold deposits in Guizhou province, and the leaching process is rapid in reaction and environmentally friendly, with low toxicity and high efficiency, which is worthy of further study.