Acid leaching process of valuable metals from limonite-type laterite nickel ore

Nickel is a kind of strategic rare metal. To meet the demand for nickel-ferro alloy, producing elemental nickel or nickel alloy from low-grade laterite ore is the main method. In this study, the selective leaching of valuable metals from Indonesian limonite-type laterite nickel ore by hydrochloric acid was investigated. The results showed that the leaching rates of nickel, cobalt, manganese, iron and magnesium were 34.3%, 90.67%, 64.23%, 76.46% and 48.12%, respectively when the concentration of hydrochloric acid was 10 mol/L, the particle size of raw material was 74 μm, the leaching temperature was 353 K, the ratio of solid to liquid was 1:4, and the leaching time was 120 min. Hydrochloric acid as an industry byproduct is easy to recycle and regenerate. The leaching kinetics of nickel, cobalt and manganese showed that their leaching process did not conform to the widely used shrinkage core model. However, the Avrami equation had a good linearity. According to the Arrhenius formula, the apparent activation energies of nickel, cobalt and manganese in the leaching process were 7.96, 4.00 and 4.98 kJ/mol, respectively. The activation energies of all three elements were in the range of 4 ~ 12 kJ/mol, and the influence of leaching temperature on the reaction rate constant was not obvious. Therefore, the leaching process of nickel, cobalt and manganese is controlled by diffusion. This study can provide a theoretical reference for the efficient development and utilization of limonite-type laterite nickel ore.