The Effect of Magnesium Sulfate, Temperature, Holding Time and Reductant on Carbothermic Selective Reduction of Limonite.

The limonite has low nickel grade of laterite family and contains goethite [FeO (OH)] and hematite (Fe₂O₃). The new way for reducing the other elements is selective reduction. Selective reduction is the better way to get the product of Fe-Ni. The nickel ore obtains some variations temperature of 950 °C, 1050 °C and 1150 °C with the holding time 60, 90 and 120 minutes and also the different of anthracite coal reductant percentage those are 5, 10 and 15%. The reduction of laterite was using magnesium sulfate additive is around 10wt% and continued with the process of magnetic separation. X-ray Diffraction (XRD) results show the dominant phases are magnesioferrite (Fe₂MgO₄), magnetite (Fe₃O₄), fayalite (Fe₂SiO₄), iron-nickel (FeNi), iron sulfide (FeS) and wustite (FeO). XRF (X-Ray Fluorescence) characterization shows the optimum process for the weight per cent and recovery of nickel at the temperatures 1150 °C for 90 minutes with 5% reductant those are 2.086 wt.% and 80.68%, respectively. The microstructure consists of ferronickel with the largest grain size is 13.2 µm and impurities elements. It is indicated the selective reduction could increase the Ni per cent and separated Ni from its initial form. [ABSTRACT FROM AUTHOR]