Study effect of Na₂SO₄dosage and graphite on the selective reduction of saprolite from nickel grade, recovery, and iron-nickel grain size

The selective reduction of nickel and adequate growth of ferronickel grains is imperative for efficient preparation of ferronickel from nickeliferous laterite ore via the process of direct reduction followed by magnetic separation. The reduction behaviours of a saprolite laterite ore in the presence of sodium sulphate were investigated, with an emphasis on thermodynamic analysis, selective reduction ratios and kinetics. To separate the interactions between Ni and Fe, chemical titration analysis was adopted to determine the contents of various Ni and Fe species in the roasted pellets and a modified equation to assay metallic iron content. This process uses the addition of sodium sulphate as the additive and graphite as the reductant. The additive and reductant are the optimal n the separation process to limit the form of iron oxide. The Na2SO4 dosage plays an important role in the process that causes its behaviour to reduce the growth of iron oxide. In this experiment, the study effect of Na2SO4 dosage with graphite as a reductant on the nickel grade, recovery and grain size of iron-nickel has been investigated in the variation of Na2SO4 dosage of 5, 10, and 15 % with reduction temperature 1150 °C for 60 minutes and the reductant stoichiometry is 0.125 from equilibrium condition is equal 0.63 gram. The mineralogical composition of the raw and reduced samples was analysed by XRD, AAS, and XRF. The grain size was measured with an optical microscope. The optimum Na2SO4 dosage is 15 %, which produces a concentrate with nickel grade, and the recoveries are 5.65 wt.% and 30.33 % when the grain size is greater than the high level of dosage because the liquid phase provides access for the transfer of metal ions and then prompts the growth of ferronickel grains.