Study On Take Off The Fluorine Zinc Chloride Of The EAF By Fire Method

Zinc is a very important metal for the national economy.In the field of galvanizing and anticorrosion,consumption accounts for more than 50%of the total zinc consumption,and it is increasing year by year.Due to the recycling of scrap iron and steel used for electric arc furnace,it is used in the galvanized zinc with steel recycling and enrichment to electric dust.The dust of electric arc furnace?EAF?is an important resources rich Zn,the phase composition mainly ZnO,ZnFe₂O₄,MgFe₂O₄,Fe₃O₄,and main chemical composition is zinc oxide.It is very meaningful to recycle zinc for the dust of EAF in Zinc recycling.But the dust of EAF generally contains a lot of F,Cl and other elements,is very unfavorable for the recovery of zinc,to reclaim the dust of EAF in using zinc to deal with F and Cl elements.This study uses the characteristics of low melting boiling point of fluorine and chlorofluoric compound to roast the dust of EAF at high temperature and remove the F and Cl.Using the low boiling point of the single metal zinc,the Zinc Oxide is reduced to the metal zinc in the high temperature reduction condition to make it volatilized,thus the zinc in the furnace dust is separated.In this paper,the pyrometallurgical process is used to remove F?Cl?Zn from the dust of EAF and use the second calcination.In one roasting the dust of EAF removal of the fluorine chlorine and other volatile substances,and then then carbon is added to the roasted products and the direct reduction process of the dust of EAF to reduce the dezincification directly.The effects of roasting temperature and holding time of heat preservation ont removal F?Cl of the dust of EAF,and the effect of reducing temperature,reducing time and carbon oxygen ratio on removal Zn of the dust of electric furnace was studied.The basic properties of the furnace dust were measured by laser particle size analyzer,X-ray fluorescence analyzer,X-ray diffraction analyzer and scanning electron microscope.The dust particle size of the electric furnace used in this experiment is below 61?m,and the content of Zinc Oxide is over 50%.The composition of the phase is mainly ZnO,ZnFe₂O₄,MgFe₂O₄ and Fe₃O₄,which is formed by a lot of small spherical particles,and the surface is distributed with floc.According to the research,the best condition for the removal of F?Cl from the dust of EAF is 1050?,holding time 120min,the defluorination rate reaches 98.6%,and the removal rate of chlorine is 89.7%.After calcined the furnace dust and two calcination,the Zinc Oxide with high purity six side zinite structure is obtained.The best process conditions are reduction temperature 1250,reduction time 120min,carbon oxygen ratio 1.2:1,and zinc removal rate of 89.1%.By analyzing the XRD patterns of the dust of EAF with different roasting temperatures and different holding times,it was found that the phase composition of the dust of EAF does not change with the roasting temperature and holding time.The dust of EAF was calcined at 1050?,the phase composition of the flue dust of the electric furnace at different calcination temperature and different holding time was analyzed by XRD test.In the test results,the phase composition of the furnace dust was not changed with the change of calcination temperature and holding time.The content of Zinc Oxide in the surface furnace dust was very high,and the fluorine and chlorine compounds volatilized in their XRD don't show it.The dust of EAF was calcined at 1050?,by analyzing the SEM image,when the calcination temperature is the same,prolonging the holding time will cause the small particles in the dsutof EAF to adhere and accumulate to form large particles.Within a unit area,the gap between large particles will increase and the small particles decrease.And the accumulated large particles will be more dense as the holding time increases.