Effect of boric acid–sodium sulfate mixture on the selective reduction process of saprolitic nickel laterite

Abstract

In selective reduction of nickel laterite process, sulphur-bearing materials as the sole additive have been studied to improve the nickel grade by inhibiting the metallisation of iron. However, the sulphidation reaction lowers the recovery of nickel. Therefore, the selection of proper additives carried out. Combining boric acid and sodium sulphate as additives, in selective reduction of saprolitic nickel ore has been investigated clearly in this work. Nickel saprolite, additives and coal were mixed and pelletised into 10–15 mm of diameter. The pellets were heated in a muffle furnace and before the wet magnetic separation process. The selective reduction process of saprolite with the mixture of boric acid and sodium sulphate at 20 wt% dosages (with 75–25 ratio), reductant amount of 0.4 stoichiometry of carbon, and temperature reduction of 1250°C has produced ferronickel contains nickel grade and recovery of 18.29% and 74.87%, respectively.