Study On Vacuum Carbothermal Reduction Process And Mechanism Of Zinc-containing Electric Furnace Dust

Recently,the output of electric furnace steelmaking has increased sharply.For every ton of steel smelted in the electric furnace,there will be 2%dust.Therefore,the output of zinc-containing electric furnace dust has increased dramatically.Due to its small particle size and complex composition,it is harmful to production equipment and the environment.Features,through comprehensive recycling of zinc-containing electric furnace dust can effectively reduce the harm of metallurgical solid waste,protect the ecological environment,and the use of corresponding process technology can further recover valuable metals in electric furnace dust,turning waste into treasure.Therefore,this paper carried out the research on the reduction and recovery of zinc in the dust of zinc-containing electric furnace from the aspects of thermodynamics,laboratory research,kinetics and pilot test.First,through thermodynamic research,the starting reaction temperature of the zinc oxide carbon reduction reaction is obtained when the pressure is 1 times standard pressure,0.1 times standard pressure,0.01 times standard pressure,0.001 times standard pressure,0.0001 times standard pressure and 0.00001 times standard pressure.1224k,1052k,937k,856k,792k,and 755k,respectively,indicating that the reduction reaction is more likely to occur as the pressure decreases.In laboratory research,when the moisture content is12%-13%and the binder addition amount is 2%,the falling strength of the pellets meets the experimental requirements;during the vacuum carbon thermal reduction experiment,the reducing agent is blue carbon,and the reduction temperature 1000 o C,carbon-to-oxygen ratio 1.1 and reaction time 30min are the best process parameters.The dezincification effect can reach more than 99%,and through the orthogonal test results,the zinc metal element can be successfully collected.Using XRD phase and microscopic morphology analysis to study the reduction products of vacuum carbothermal reduction of zinc-containing electric furnace dust,the results show that as the reaction time prolongs during the reduction process,decomposition of iron zincate and other oxides has occurred.,Lead and iron oxides are reduced and zinc and lead metals are quickly volatilized and discharged,iron oxides are further reduced to metallic iron,and other compounds are formed during this process.The kinetics of the process of vacuum carbothermal reduction of zinc-containing electric furnace dust by linear regression analysis method showed that the reduction reaction order of zinc is one stage,and the diffusion step is a restrictive link.Obtain relevant process routes and experimental parameters through laboratory research,and conduct pilot tests on this basis.According to actual production requirements,design pilot equipment and adjust relevant test parameters to obtain moisture content of 12.5%-13%,pelletizing time 25min,the addition amount of bentonite is 2.5%,the drying temperature is 160 ~oC,the reduction time is 8h,the reduction temperature is 1050 ~oC,and the carbon-to-oxygen ratio is 1.2 as the best pilot test parameters.The final purity of the metal zinc condensate collected is high,and the Zinc electric furnace dust recovery processing,but there are still some deficiencies,still need to further improve equipment and adjust related test parameters.