Proof-of-Concept Study on Extraction of Nickel from Low-Grade Ultramafic Nickel Concentrates

The authors proposed a two-stage solid-state nickel extraction method that avoided the smelting of magnesium silicates in the ultramafic nickel concentrate. The mixture of the nickel concentrate and metallic iron powder was heated at 950 °C followed by slow cooling to 750 °C and over 90% of nickel was extracted from pentlandite into the ferronickel alloy phase. The alloy contained 20–30 wt% nickel and had a characteristic grain size of 40–50 μm.