A New Hydrometallurgical Process For The Treatment Of Low Grade Ni-Mo Ore

Ni-Mo ore is a unique polymetallic complex ore in China and is considered a great economic value because of the abundant reserves,wide distribution and high grade of valuable metals.Usually,the grade of Ni and Mo are in the range of 0.2-7%.However,the Ni and Mo in raw ore are generally in the form of microcrystalline or amorphous and are closely related to the organic carbon and pyrite in the raw ore.It is hardsome to achieve the clean and efficient goal to extraction Ni and Mo from Ni-Mo ore.Due to that,Ni-Mo ore has been ignored for several decades.Focus on the development of Ni-Mo ore,this study proposes a novel hydrometallurgy process with shearing-enhance ammonia leaching-solvent extraction-ion exchange processes to extract Ni and Mo from Ni-Mo ore,and the following results are obtained in this study.The Thermodynamics diagrams of,Mo-S-H₂O,and Ni-NH₃-H₂O were drawn in this study to demonstrate the predominance region during the ammonia leaching.The thermodynamic results showed that it was feasible to introduce O₂ as an oxidizing agent for leaching Ni-Mo ore under the ammonia system,and the result also showed that it is favorable to promote the leaching process of Ni-Mo ore by increasing the concentration of ammonia.The thermodynamic characteristics of the solvent extraction process under LIX 84-I as extraction agent and the chemical formula of molybdate under weak acid condition were investigated to certify the feasibility of the processThe results between the shear-enhanced leaching and stir leaching shown that shearing enhances technology could optimize the kinetics transfer process by refining the size of oxygen bubble and mineral particle,improving the leaching efficiency of nickel and molybdenum.Moreover,under the optimum condition of 50℃,the oxygen flow of 0.6 L/min,the shearing speed of 3000 rpm,the liquid to solid ratio of 8:1,the ammonia concentration of 1:3,the ammonia carbonate of 5%compared with Ni-Mo ore,and the leaching duration of 7 h.The leaching efficiencies of nickel and molybdenum were 86.60%and 88.52%,respectively.Valuable metals were separated effectively during the leaching process,which was supported by comprehensive experiment.The recovery efficiency of nickel reached the peak of 98.63%under the optimum solvent extraction condition of 25℃,the LIX84-I concentration of 15%Vol,the phase ratio of 1:1,and the p H of the leachate of 10.The concentration of nickel in the stripping solvent was 57.48 g/L after stripping 15 times by the 100 g/L sulfuric acid.In addition,molybdenum could be recovered by ion exchange with the recovery efficiency of 98.81%when D301 resin was introduced to adsorbed molybdenum at the raffinate p H of 4 and then stripped by ammonia hydroxide.The concentration of molybdenum in strip solvent was 45.98g/L.During the whole process,the recovery efficiencies of nickel and molybdenum were 85.41%and 87.47%,respectively.The results of kinetics experiments showed that the leaching process of molybdenum follows the Drozdov kinetics model.The apparent rate constant of reaction（K_m）and 1/T follows the formulas of f（x）=-4.267x+7.401 with the apparent activation energies of 35.48 k J/mol.The leaching process of molybdenum is controlled by chemical reaction.