Selective leaching of nickel from low-sulfur Ni-Cu matte at atmospheric pressure

A process of the selective leaching of nickel from low-sulfur Ni-Cu matte at atmospheric pressure was described. This matte was obtained from high grade Ni-Cu matte by magnetic separation, which mainly contained Ni-Cu alloy and a small quantity of sulfides. Firstly, the acid-oxygen (CuSO4-H2SO4-O2) leaching of the matte was conducted at atmospheric pressure. When the solution pH value reached 1.0–2.0, the oxygen flow was ceased. Then, the aqueous copper was rejected by cementation reaction with Ni in the alloy. The mineralogical characteristics of the matte in the process were analyzed by X-ray diffractometry, optical microscopy and scanning electron microscopy. And the effects of variations in temperature, particle size distribution, oxygen flow rate, pulp density, initial acid concentration and initial concentration of copper ion were investigated.