Pressure acid leaching of arid-region nickel laterite ore: Part IV: Effect of acid loading and additives with nontronite ores

The extraction of nickel from nontronite-rich laterite ores is enhanced by either increasing the acid loading, or the addition of a small amount of sodium to the process water. The results of this study indicate that at least 15% less acid can be used to get the same extraction of nickel from a nontronite-rich laterite ore in process water containing 5 g/L sodium ion, compared with the same ore in fresh process water. In addition, nickel extractions from a second nontronite-rich laterite ore were increased by up to 3% compared with fresh water, if process water sodium ion levels is present at 5–11 g/L at a given acid loading of 420 kg/t ore.