Copper–Nickel Ore Processing by Low-Temperature Roasting in Mixture with Ammonium Sulfate

The phase transitions of sulfide minerals—pentlandite and chalcopyrite—are tested in roasting with mixture with ammonium sulfate. The behavior of the mixture during roasting is assessed via the synchronous thermal and X-ray phase analyses, and by scanning electron microscopy. The basic optimal technology parameters for the efficient processing of sulfide-bearing copper–nickel ore are selected to be: the roasting temperature of 400 °C, the ore: ammonium sulfate ratio of 1:10, the particle size of –40 m and the roasting time of 240 min. An important condition is joint milling of ore and ammonium sulfate down to the specified size. Given these parameters, the later on water leaching of clinker provided extraction of 94.8% of copper, 91.5% of nickel and 82.3% of cobalt. The research findings are of essential practical interest owing to the high recovery of the target minerals.