Abstract:Effects of reaction temperature, solid-liquid ratio, oxygen partial pressure, stirring speed, concentration of leaching solution and reaction time on leaching and kinetics of cobalt and nickel from Ni-Co sulfide slag were studied. The results show that average leaching rate of Ni and Co is 94.02% and 94.64% respectively under the optimum conditions including reaction temperature of 120 ℃, solid-liquid ratio of 1︰30 g/mL, oxygen partial pressure of 0.7 MPa, stirring speed of 230 r/min, concentration of sulfuric acid of 1 mol/L, and reaction time of 130 min. Leaching of Ni and Co from Ni-Co sulfide slag conforms to shrinking core model and internal diffusion is a limiting step of reaction, and apparent activation energy is 3.65 kJ/mol and 6.02 kJ/mol respectively. Leaching rate of Ni-Co sulfide slag can be improved by reducing slag particle size and solid-liquid ratio, maintaining high concentration of leaching solution, stirring speed and oxygen partial pressure.