Extraction of molybdenum from low-grade Ni–Mo ore in sodium hypochlorite solution under mechanical activation

The extraction of molybdenum from low-grade Ni–Mo ore in sodium hypochlorite solution under mechanical activation was studied. The results show that the following parameters such as leaching time, liquid-to-solid ratio, pH value, sodium hypochlorite and sodium carbonate concentrations have significant effects on the recovery rate of molybdenum. The recovery rate of molybdenum reaches 96.3%, which is much higher than conventional agitation system (73.0%). It is suggested that an increase of surface area and phase transformation under mechanical activation should be responsible for the improved leaching recovery of molybdenum. After purification, the leaching liquor was acidified with HCl to precipitate ammonium molybdate followed by calcination to obtain high purity MoO3.