Abstract:Separation of zinc and iron is the key in zinc hydrometallurgy. The residue produced by hematite process is stable and friendly to environment, so it has great application potential. The existing state and content of Fe and S in hematite precipitation process was studied in the system of ferrous sulfate and zinc sulfate. The results show that under the conditions of reaction temperature 185 ℃, oxygen partial pressure 0.4 MPa, rotation speed 600 r/min and seed dosage 25 g/L, the reaction time 3 h, Increasing the reaction temperature from 170 ℃ to 200 ℃ can effectively increase the iron content in the residue, reduces the binuclear coordination exchange adsorption between the sulfate radical and the surface of the hematite particles. At the same time, the dispersion between the hematite particles is enhanced, and the adsorption of sulfur between the particles is reduced. The S in the liquid after iron removal is in the form of SO42-. The reaction time is prolonged from 1 h to 3 h, the iron removal efficiency increases from 91.23% to 93.63%, and the products are all α-Fe2O3. In addition, Fe2+ is oxidized faster at the initial stage of reaction, so that part of Fe3+ in the solution is in a state of supersaturation, and attached to the spherical seeds at a faster nucleation rate and grow into spindle-shaped small particles.