Effect of sulfur content in reductants with variations of 0.5-1.5 stoichiometry in the selective reduction process of saprolitic nickel ore

Abstract

Indonesia supply accounts for 16 % of the world’s lateritic nickel ore, with the estimation reaching 1.391 billion tons. The process of refining lateritic nickel ore can be considered as one of the main problems faced by the world mining industry, taking into account the economic and energy aspects. This research was carried out to investigate the effect of sulfur in reductants on the selective reduction process of saprolitic nickel ore. This research used saprolitic ore using 10 wt.% additives (sodium sulfate). Two kinds of coal reductants containing 2.68 % and 5 % of sulfur were also used. Nickel ore, additives, and reductant were mixed homogenously prior to the pelletization into a diameter of 10-15 mm. The reduction of pellets was carried out at temperature variations of 950, 1050, and 1150 °C for 60 minutes, followed by magnetic separation using 400-600 Gauss of the magnetic field to separate magnetic-concentrate, which contains ferronickel, and non-magnetic tailing, which contain impurities. The reduced ore characterization was performed by using X-ray Diffraction, Optical Microscope, X-ray Fluorescence, and Scanning Electron Microscope. This research showed that the optimum nickel grade and recovery were obtained using 2.68 % of sulfur content in coal reductant.