Recycle Zinc Process Of Dust From Electric Arc Furnace Useless Galvanized Steel

With the rapid development of national economy, our country needed more zinc used in construction industry, automotive industry and air-conditioning manufact.Meanwhile, the mineral become poor, small and complex.With the pressure of environmental protection,the synthetical utilization of dust from electric arc furnace useless galvanized steel has increasingly become an urgent issue.The dust from electric arc furnace useless galvanized steel of Suzhou steelworks was studied in this paper. Including the analysis of thermodynamics and kinetics and seeking for leaching mechanism. And then, carry out the experiment about leaching, deferrization, extraction. The results and conclusion were as follows:1,Leaching the dust by dilute acid at normal temperature. It can be leach zinc oxide in the dust. The optimum leaching condition is that:leaching time 1h, L/S 4, sulfuric acid concentration 60g/L.2,Leaching the residue from dilute acid by high concentraded acid at high temperature. It can be leach zinc ferrite in the residue. The residue contain zinc ferrite is 96.74%. The optimum leaching condition is that:leaching time 4h, temperature 90℃, L/S 8, sulfuric acid concentration 180g/L.The leaching rate could come up to 90% by improving temperature and acid concentration, simultaneity, the impurity also coming into lixivium3,During leaching process, most of the iron in the dust was dissolved into solution. Thus, in order to meet the requirements of zinc electrowinning, iron ion was rejected from the leaching solution. Experimental results show that jarosite process, goethite process and phosphate process all can remove iron ion from solution bearing zinc ion; the precipitation rate of iron ion by phosphate process is the fastest of all three processes and phosphate process is the best process of the effect of precipitation iron in three processes.4,P204 was saponified which was used as the extractant of zinc.The extraction yield of zinc from leaching solution could reach 99.9% under favorable conditions.5,In zinc stripping process, sulfuric acid was used as an agent of zinc extractant. The zinc ion in the organic phase load could be extracted thoroughly, however, iron ion in the organic phase load was hardly extracted by sulfuric acid ion.After one step stripping, the concentration of zinc iron was raised from 11.39g/L to 70g/L. 6,The thermodynamic of leaching process shows that acid leaching process of waste galvanized steelmaking dust is a exothermic reaction; the reaction equilibrium constant is big and it is decreased with the increasing of temperature. Dynamic process research shows that its acid leaching process is the contraction not reaction nuclear model;the leaching reaction belongs to chemical reaction steps control;the reaction order is over one, the leaching rate of zinc is enhanced with the increasing of acid concentration.