Enhanced Selective Reduction of Laterite for the Highly Efficient Enrichment of Ni and Co by NaFeS₂ and Its Recycling

The substantial demand for nickel and cobalt in the power battery industry presents an opportunity to convert powdery Ni–Co–Fe alloys, derived from laterite ores via solid-state reduction followed by magnetic separation, into battery-grade nickel and cobalt feedstock. To enhance the carbothermic solid-state reduction of laterite ores for the co-enrichment of Ni and Co, NaFeS2 was synthesized and applied as the additive to achieve the selective reduction of Ni and Co oxides over Fe oxides and to reject the majority of iron oxides and gangues into the tailings via magnetic separation. A powdery Ni–Co–Fe alloy with Ni and Co grades of 13.74 and 1.19%, respectively, and the corresponding recoveries of 93.41 and 81.93% was obtained. The addition of NaFeS2 accelerated the growth of alloy particles by promoting the formation of the micro-zone liquid phase. Potential pollution problems caused by Na and S elements in tailings can be addressed through hydrothermal treatment of tailings, and also allows for the recycling of NaFeS2.