Extraction of Nickel from Magnesia–Nickel Silicate Ore

In this study, magnesia–nickel silicate ore was investigated, which contained 0.83% Ni and antigorite, chlorite, magnetite (Fe3O4), quartz, and mica as the main minerals. Chloride roasting and magnetic separation were used to treat the ore. The addition of red mud enhanced the transformation of nickel silicate to a strongly magnetic mineral mainly comprising metallic Ni and that of hematite to Fe3O4 and metallic Fe. Test results showed that a Ni concentrate with a Ni content of 11.41% and Ni recovery of 92.77% was achieved under the following optimal conditions: roasting temperature: 1373.15 K; roasting time: 120 min; CaCl2 dosage: 20%; coke dosage: 14%; red mud dosage: 30%; magnetic field intensity = 0.14 T; and grinding fineness: 90% < 0.05 mm. The major minerals in the Ni concentrate were Fe3O4, metallic Fe, and metallic Ni. Sc entered the magnetic separation tailings, creating a favorable condition for the further extraction of Sc by hydrometallurgy. The thermodynamic calculation results are in good agreement with the test results.