Research On The Leaching And Separation Behavior Of Zinc And Iron In Lead-silver Residue Containing Vitriol

Lead-silver residue containing vitriol is producting in zinc smelting process, which contains a large sum of valuable metal. If lead-silver residue is not recycled, it will cause a waste of resources and environmental pollution. Aiming at the characteristics of lead-silver residue containing vitriol in Inner Mongolia, this paper conducts mineralogy study and determines the sulfatizing roasting-leaching process route, at the same time, investigates the influence of sulphuric acid consumption, calcination temperature, calcination time, leaching time, leaching temperature, liquid-solid ratio on metal leaching rate. Aiming at the phenomenon of high iron-low zinc in the leaching solution, this paper proposes the technical plan of removing iron by phosphate and conducts exploratory experiment and removing iron experiment.Mineralogy study shows that in lead-silver residue containing vitriol lead exists in anglesite and vitriol, silver exists in zinc ferrite, zinc exists in zinc sulfate, zinc hydroxide and zinc ferrite, iron exist in vitriol, zinc ferrite and iron hydroxide.In the sulfatizing roasting-leaching process route, most of zinc and iron in the lead-silver residue containing vitriol are leached through controlling the reaction condition. The suitable technological conditions in the sulfatizing roasting-leaching process route are:sulphuric acid consumption to be 57wt.%, calcination temperature to be 250℃, calcination time to be 80 min, water leaching temperature to be 40℃, water leaching time to be 60min, liquid-solid ratio to be 5.5. Under these conditions, the leaching rate of zinc and iron reaches to 96% and 88%.The technical process of removing iron by phosphate is implied on the leaching solution to separate zinc and iron. The suitable technological conditions in the technical process of removing iron by phosphate are:initial pH to be 1.04, reaction time to be 30min, sodium phosphate to be 1.15 times of theoretical amount, room temperature. Under these conditions, the removal rate of iron and zinc reaches to 98% and 8%.