Leaching behavior of metals from chlorinated limonitic nickel laterite

Abstract

The leaching behavior of metals from pre-reduced limonitic nickel laterite was studied using a selective chlorination–leaching process with ferrous chloride tetrahydrate as chloride agent. The effects of parameters in selective chlorination and leaching process were investigated. It was found that the optimum conditions for selective chlorination were chloride agent addition of 40wt.% and time of 150min at 460°C. Liquid/solid ratio in leaching process, leaching time and temperature had little influence on metal extraction. As the initial pH value of leaching solution decreased from 6.85 to 1.00, the extractions of Fe, Ni, Co, Al, Cr and Mn increased slightly while that of Mg increased from 36.98% to 43.23%. Under the determined conditions, 91.78% Ni, 87.64% Co, <2% Fe, 2.53% Al, <1% Cr, 36.98% Mg and 63.04% Mn were leached by water. The chlorinated ore and leaching residue were characterized by X-ray diffraction and scanning electron microscope.