Abstract:Aiming at the problems of low oxygen utilization rate and slow dissolution of sphalerite in the pressure leaching process of zinc concentrate, the strong oxidizability of Fe3+ in zinc leaching residue and the oxygen transport efficiency of Fe2+/Fe3+ redox ion pair were used to improve the efficient oxidation of S2- in sphalerite and the utilization rate of O2, so as to realize the synergistic enhanced leaching of zinc concentrate and zinc leaching residue. The results show that Fe3+ can improve the solubility of oxygen, and the back-and-forth valence behavior of Fe2+/Fe3+ accelerates the oxidative dissolution of sphalerite (ZnS) in the leaching system, and the leaching rate and leaching efficiency of zinc are significantly improved. Under the optimal process conditions of initial sulphuric acid concentration of 95 g/L, oxygen partial pressure of 0.8 MPa, temperature of 160 ℃，reaction time of 120 min, and pH value of 3, and the addition of 6.1 g/L Fe3+ in the form of zinc leaching residue results in a high leaching rate of 98.60% of zinc, and 92.47% of iron is precipitated into the residue. The synergic leaching of zinc concentrate and zinc leaching residue is controlled by external diffusion with apparent activation energy of 15.61 kJ/mol. The kinetic equation of synergic leaching process is as follows: "1-(1-α" ")" ^"1/3" "=4.78×" 〖"10" 〗^"-3" "×{[exp(-15610/8.314T)]×c" 〖"(" "H" _"2" 〖"SO" 〗_"4" ")" 〗^"1.21" "×" 〖P("O" _"2" )〗^"0.33" "×c" 〖"(" 〖"Fe" 〗^"3+" ")" 〗^"0.43" "×t}."