Effects of Na₂SO₄ addition on the selective reduction of limonite ore from Southeast Sulawesi

In terms of its process, although only about 40% of the world's nickel reserves are classified as lateritic ore, nickel sulfide still dominates nickel laterite for its practicality. Because of the high demands on nickel, development and research on nickel mineral processing are needed to ensure that the demands are fulfilled from year to year. On this research, a study will be conducted on the effect of adding Na₂SO₄ to increase the level of nickel content in limonite by selective reduction process. The reduction process is done by heating limonite ore and coal as reducer from room temperature to 1000°C with temperature rising to 10°C/minute in mini furnace on varying addition of 0%, 5%, 10%, and 15% Na₂SO₄. After that, the reduction result is tested on XRD and AAS. It has been found that the nickel content has decreased, which is likely due to the excessive reduction time resulting in the magnetite being re-oxidized to hematite. Therefore, based on recovery calculations, the optimal addition of Na₂SO₄ is 5% by weight where the obtaining nickel content is 1.09%.