Abstract:In order to achieve the purpose of resource utilization of high nickel matte leaching residue from hydrometallurgy process of the high nickel matte, the reduction leaching behavior of copper and iron in high nickel matte residue under the action of sulfur dioxide was studied. The effects of initial sulfuric acid concentration, liquid-solid ratio, ventilation, leaching temperature, and leaching time on reduction leaching behavior of high nickel matte residue were investigated. The methods of displacement precipitation and freezing crystallization were used to separate and recover copper and iron from the reduction leaching solution. The experimental results show that under the conditions of initial sulfuric acid concentration of 100 g/L, liquid-solid ratio of 6 mL/g, reaction time of 3 h, reaction temperature of 90 ℃, sulfur dioxide partial pressure of 0.15—0.2 MPa, the leaching rates of iron and copper are 99.35% and 77.46% respectively, and iron in the leaching solution is almost all ferrous ions. Under the conditions of sulfuric acid content of 20—30 g/L, temperature of 70 ℃, iron powder addition of 5.7 g/L, and reaction time of 40 min, the copper precipitation rate from reduction leaching solution reaches 99.70% and the copper content in slag is 67.91%. Finally, ferrous sulfate was prepared by freezing crystallization of the liquid after copper deposition. Iron precipitation rate is 72.6% and the purity of ferrous sulfate heptahydrate is 92.93% under the conditions of temperature of —10 ℃, holding time of 20—30 minutes, and initial sulfuric acid concentration of 100 g/L.