Recovery And Utilization Of Znic From Iron Dregs

In the process of industrial wet zinc,goethite process is used to remove iron in almost smelting enterprises.For one ton of zinc produced,0.5 tons of solid waste is generated,a large number of zinc-containing solid waste produced,of which the zinc content is 12%?14%.It belongs to dangerous solid waste.Without proper treatment,it will cause environmental pollution and serious waste of resources.In this paper,the solid waste in zinc smelting slag of an enterprise in Xiangxi has been studied,which mainly includes three parts:?1?Study on the preparation of active zinc oxide from zinc-smelting solid waste by ammonia leaching method:The effects of temperature,time,liquid-solid ratio and ammonia concentration on leaching rate were studied by surface response method,and the optimum technological conditions were obtained.The leaching rate of zinc in solid waste can reach 99.78%when the temperature is 20?,the time is 1.7 h,the liquid-solid ratio is 4.4 m L/g and the ammonia concentration is controlled at 8.2%.Ammonium sulfide was used to remove impurities from leaching solution,and then NH₃HCO₃ was added to the leaching solution after ammonia evaporation to prepare active zinc oxide.After testing,the performance of active zinc oxide conformed to the chemical industry standard HG/T 2572-2012.?2?Adsorption of zinc in acid leaching solution of zinc-smelting solid waste by macroporous resin:The effects of temperature,time,liquid-solid ratio and acid concentration on leaching rate were studied by surface response method,and the optimum technological conditions were obtained.The leaching rate of zinc in solid waste can reach 99.91%when the temperature is 25?,the time is 2h,the liquid-solid ratio is 4.4 m L/g and the acid concentration is controlled at p H=4.0?4.2.The selective adsorption and adsorption capacity of three macroporous resins D401,D402-II and D405 for zinc in leaching solution were studied,and the best D402-II resin was selected.The adsorption capacity of the resin for zinc ion increased first and then decreased with the increase of p H,and reached the maximum at p H=5.5,which was213.2 mg/g.When eluting,electrolytic zinc anode solution with sulfuric acid concentration of 1.5 mol/L can be used as desorbents,and the desorption rate can reach more than 97%.?3?Study on recovery of zinc from zinc-smelting solid waste by EDTA coordination method:The effects of temperature,time,liquid-solid ratio and ammonium salt of EDTA concentration on leaching rate were studied by orthogonal experimental design,and the optimum technological conditions were obtained.The leaching rate of zinc in solid waste can reach 99.88%when the temperature is 40?,the time is 2h,the liquid-solid ratio is 6 m L/g and ammonium salt of EDTA concentration is 0.4mol/L.The leaching solution is precipitated by?NH₄?₂S and filtered,then was dried to a constant weight.The analysis shows that the main component of zinc sulfide,which can be used as raw material for zinc smelting.