Sulphuric acid leaching kinetics of pre-reduced laterite ores

The laterite ore with high iron content can be treated by acid leaching method to extract nickel.To speed up the nickel extraction rate and minimize the acid consumption,reduction is a feasible pretreatment.In this paper the sulphuric acid leaching kinetics of pre-reduced laterite ore was invested.The effects of leaching temperature(30～70 ℃) and H2SO4 concentration(0.01～0.5 mol·L-1) on the extraction rate of nickel and iron were examined.The result indicated selective reduction could speed up the nickel extraction and obstructed the iron dissolution.The nickel extraction followed Avrami equation and the apparent activation energy was(15.40±0.18) kJ·mol-1.The dissolution rate of iron was inner-diffusion controlled and the apparent activation energy was(55.16±1.37) kJ·mol-1.