Test Study on Leaching of Zinc and Iron From Neutral Leaching Residue by Oxygen Pressure Using Sulfuric Acid

Leaching of zinc and iron from neutral leaching residue in zinc hydrometallurgical process by oxygen pressure using sulfuric acid has been researched.The optimum conditions were determined through tests.The effects of oxygen pressure,residue particle size,sulfuric acid concentration,leaching time,leaching temperature,liquid to solid ratio and amount of sodium lignosulphonate on leaching of zinc and iron were examined.The results showed the leaching of zinc and iron could reach 98% and 60.87% respectively at the conditions of liquid to solid ratio of 3∶1,H2SO4 initial concentration of 140~150 g/L,leaching temperature of(150±5) ℃,oxygen pressure of 0.8 MPa,leaching time of 80~90 min,sodium lignosulfonate amount of 0.15%.The leaching reaction of iron was inhibited by decreasing the final concentration of H2SO4 and increasing leaching temperature.