Abstract:Leaching rate of iron is in a low level due to existence of complex phase of iron during zinc pressure leaching. There are still some amount of iron in residue of zinc pressure leaching. Taking the residue from Guangdong province as research object, mineral liberation analysis is carried out at first. Then, sulfuric roasting combined with solution leaching was proposed to enhance decomposition and dissolution of complex phase of iron. Leaching rate of Fe and Zn is 83.31% and 97.06% respectively under the optimum conditions including temperature of 300 ℃, mass ratio of H2SO4 to residue of 0.4, roasting time of 2.0 h, leaching time of 1.0 h, and leaching temperature of 25 ℃, and L/S=5/1. Finally, leaching kinetics of roasting residue is successfully modeled by chemical reaction model with apparent activity energy of 23.18 kJ/mol, and semiempirical kinetics equation is obtained.