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