From Yuanjiang Low-grade Laterite Nickel Ore Leaching

The current situation of leaching nickel laterites was summed up in this study.The purpose of this experiment was to research 2 new leaching approach to extract Ni from nickel laterites with low costs,and low pollution.Based on the analysis of thermodynamics and mechanism of the leaching process of nickel laterites with HCl under normal pressure,the effects of leaching rate of Ni,Co,Mn,Fe and Mg.The optimum conditions are obtained as follows:particle size=0.15mm,the mass ratio of acid/ore=2.7,leaching temperature=353K,solid/liquid ratio=1:4,stirring speed=300r/min,leaching time=2h.The leaching rate of Ni,Co,Mn,Fe and Mg are 93.94%,58.5%,94%,56%,94%。The kinetics of leaching nickel laterites was also investigated.The results show the experimental data of the leaching rate accord wih the product layer diffusion-controlled shrinking core model.The activation energy of Ni,Co,Mn calculated through the Arrhenius equation was 11.56kJ/mol,11.26kJ/mol,10.77kJ/mol.The reaction was diffusion control.Mechanism of chloridizing roasting was researched.The effect of leaching rate of Ni,Co,Mn,Fe and Mg was studied.The experiments indicate that the optimal conditions are that:roasting temperature 673K, roasting time 15 min,the mass ratio of NH₄Cl/ore 0.8:1,the dissolution yields of nickel,cobalt,manganese,iron and magnesium with water as leaching reagent in 5min at room temperature are 80%,60%,99%,58%, and 19%,respectively.