Extraction of molybdenum and nickel from Ni–Mo ore by pressure acid leaching

A direct hydrometallurgical route for nickel and molybdenum extraction from a nickel–molybdenum (Ni–Mo) ore using pressure acid leaching was studied. The nickel and molybdenum were extracted by acid leaching under oxygen pressure. Compared with traditional roasting methods, this hydrometallurgical method eliminates SO2 and As2O3 emission (the Ni–Mo ore containing 15%–25% S). Compared with existing alkali leaching recovery of molybdenum process, almost all the nickel and considerable molybdenum were extracted in the acid leaching process. Under oxygen pressure conditions, almost all the nickel and a substantial part of the molybdenum were dissolved into the acid leaching liquor and the other part of the molybdenum was left in the acid leach residue. The acid leach residue was further leached under alkaline (NaOH) conditions. Under optimal experimental conditions, the extraction rates nickel and molybdenum reached 97% and 96%, respectively.