| Cyanide-free extraction of gold is a key technology for the sustainable development of gold smelting industry. Decomposing the roasted gold concentrate with sulfuric acid can dissociate gold from pyrite, realizing the enrichment of gold which facilitates the subsequent leaching process of gold with ferric chloride solution. The effects of sulfuric acid concentration, excess coefficient and temperature on the decomposition rate of iron were studied. The optimum decomposition temperature and time, and the optimum excess coefficient of sulfuric acid were 180 ℃, 90 min and 1.2, respectively. Under these conditions, the decomposition rate of Fe was 92.14% and the content of gold increased from 51.67 to 106.1 g/t. For the leaching process, the optimum temperature and time, the liquid-solid ratio were 80 ℃, 90 min and 1.5, respectively. Under these conditions, the gold leaching rate was 96.8%. |
