Thermodynamic Analysis of Sulfurization of Ferronickel

The demand for nickel for batteries is increasing rapidly with the rapid development of new energy vehicles. Currently, many companies are glad to produce ferronickel alloys from laterite nickel ore due to the gradual exhaustion of sulfide ore. However, there is still little research on the thermodynamical analysis of sulfurization from ferronickel into nickel matte to produce nickel sulfate. Therefore, the thermodynamic analysis on the sulfurization of ferronickel using FactSage was investigated in this study. The results indicate that the overall sulfurization path of iron is Fe2O3 -> Fe3O4 -> FeO -> Fe -> FeS and that of nickel is NiO -> Ni -> Ni3S2 under oxygen-containing smelting conditions. Nickel has a stronger affinity for S than Fe but has a weaker affinity for O than Fe. Nickel and iron can be separated by controlling the smelting conditions with about 1.0 x 10(-2.5) atm < P-O2 < 1.0 x 10(-2.5) atm and 1.0 x 10(-2.5) atm < P-SO2 < 1.0 x 10(0.3) atm. Sulfurizing reagents FeS2, NiS, NiS2, and S-2 can sulfurize ferronickel under specific condition. Nickel-rich matte can fuse ferronickel, but it can only be a transition process of sulfurizing ferronickel. This study reveals the phase transition paths of ferronickel during smelting sulfurization. It illustrates the sulfurizing behavior of different sulfurizing reagents. The results provide useful reference methods for consolidating the connection between laterite ore and the new energy industry.