Abstract:Thiosulfate gold extraction is a green and environmentally friendly non-cyanide gold extraction method, but the efficient recovery of gold in gold leaching solution needs further research. Using methyl trioctylammonium chloride (TOMAC) as extractant,, the effects of extraction conditions (extractant concentration, phase ratio, extraction time) and the properties of gold leaching solution (pH value, thiosulfate concentration, initial Au(Ⅰ) concentration) on the extraction performance of Au(Ⅰ) by TOMAC were investigated. The results show that at room temperature, TOMAC as extractor can efficiently extract Au(Ⅰ) from gold thiosulfate leaching solution. When A/O=1, pH=9, thiosulfate concentration is 0.1 mol/L, TOMAC concentration is 1.8 g/L, the low concentration of gold (0—25 mg/L) can be extracted almost completely. Au(Ⅰ) in TOMAC organic phase can be effectively stripped by 1 mol/L NaCl. The extraction mechanism of Au(Ⅰ) by TOMAC is as follow: TOMAC forms [C25H54N]3[Au(S2O3)2] complex through ion exchange of Cl- on its surface with Au(Ⅰ) in solution. TOMAC has good extraction performance for Au(S2O3)23-, and can realize efficient recovery of Au(Ⅰ) in thiosulfate gold leaching solution, which has potential application value for thiosulfate gold leaching technology.