Abstract:Reducing leaching behavior of zinc and indium from zinc leaching residue in SO2-H2SO4 system was studied. Effects of reaction temperature, rotational speed, L/S, initial sulfuric acid concentration, and SO2 partial pressure on leaching behavior and leaching rate of zinc and indium were investigated. The results show that SO2 can be used for reducing leaching of zinc leach residues, which can effectively improve leaching rate of zinc and indium. Leaching behavior and kinetics of zinc and indium during reduction leaching of zinc leaching residue are in accordance with second-order reaction equation and controlled by chemical reaction with apparent activation energy of 21.72 and 39.16 kJ/mol respectively. Leaching rate of zinc and indium can be enhanced by increasing initial sulfuric acid concentration, enhancing L/S and initial sulfuric acid concentration has little effect on leaching rate of zinc and indium, while enhancing partial pressure of sulfur dioxide has a significant effect on leaching rate of zinc within a certain range. Over 96% of zinc and 95% of indium in zinc leaching residue are leached under the conditions of reaction temperature of 105 ℃, stirring speed of 500 r/min, L/S of 8, initial sulfuric acid concentration of 120 g/L, SO2 partial pressure of 200 kPa, and reaction time of 150 min.