Study on leaching of molybdenum and nickel from Ni-Mo ore using sodium chlorate

The leaching of molybdenum and nickel from a Ni-Mo ore was investigated by acidic oxidative leaching with sodium chlorate followed by caustic leaching of the acid leach residue. The results indicated that the sulphides of nickel and molybdenum in the Ni-Mo ore were oxidised and dissolved in the solution. The molybdenum remaining in the residue was further recovered by direct caustic leaching. The leaching of nickel and molybdenum reached 92 and 60% respectively, with sodium chlorate consumption of 60 g per 100 g ore and hydrochloric acid consumption of 0.52 mol per 100 g ore at a L/S ratio of 3 : 1 and 90 degrees C for 2 h. After caustic leaching of the acid leach residue with sodium hydroxide consumption of 45 g per 100 g dried residue at a L/S ratio of 3 : 1 and 40 degrees C for 15 min, the total leaching of molybdenum increased to 96%. A conceptual process flowsheet for the leaching of the Ni-Mo ore has been developed.