Abstract:The effects of Fe3 and Fe3 /Fe2 ratio on copper leaching rate from earthy copper ores were investigated. The leaching mechanism of iron ions to improve copper leaching during acid leaching process was analyzed. The results indicate that copper leaching rate is 62.4%, which is improved by almost ten percent point compared with that of non-iron ions under the conditions including mineral concentration of 30.0%, acidity of 36.8 g/L, Fe2(SO4)3 concentration of 12.0 g/L, and leaching time of 48 h. The leaching rate of free copper oxide, combined copper oxide, secondary copper sulfide and native copper sulfide are 92.6%, 70.3%, 35.6% and 11.8%, respectively, which are significantly improved except native copper sulfide. Copper leaching rate rises with drops of Fe3 /Fe2 ratio. The potential of solution and copper leaching rate are improved by increasing Fe3 concentration.