Research On Preparation Of Foamed Ceramics Materials From Waste Residues In Iron And Steel Industry

In recent years,with the continuous acceleration of the development of China’s iron and steel industry,the discharge of soild waste from the iron and steel industry has rapidly increased,which has brought serious damage to the local ecological environment.Therefore,it is indispensable to increase the resource utilization of soild wastes.In this paper,steel slag and ball clay,titanium-bearing blast furnace slag and shale slag as the main raw materials respectively,choose the appropriate foaming agent,fluxing agent,foaming agent and other additives,and set the appropriate sintering process system,using high temperature foaming method to prepare foamed ceramics materials.The porosity,bulk density,compressive strength and thermal conductivity of the foamed ceramics were measured and its pore structure was also analyzed.The crystal phases composition and microstructure of the foamed ceramics under optimal conditions were analyzed by XRD,SEM and EDS energy spectrum.The successful preparation of the foamed ceramics not only broadens the market of building insulation materials,but also provides new ideas for the resource utilization of steel slag and titanium-bearing blast furnace slag.The foamed ceramics were prepared by using steel slag and ball clay as raw materials.This chapter mainly explored the influence of steel slag content,SiC addition,Na2B4O7 addition,Na3PO4 addition and sintering temperature on the properties and pore structure of the foamed ceramics.The experimental results could get to prove the best foamed ceramics sample was obtained when the steel slag content is 30%,the ball clay content is 70%,the addition amount of SiC is 0.3%,the addition amount of Na2B4O7 is 5%,the addition amount of Na3PO4 is 2%,the firing temperature is 1110℃,the holding time is 60 min,and the heating rate in the high temperature zone is 3℃/min.The best sample exhibited the excellent comprehensive properties:bulk density of 0.419 g·cm-3,compressive strength of 5.984 MPa,thermal conductivity of 0.082 W/（m·K）.After testing,the crystalline phases of the best foamed ceramics are mainly composed of anorthite（CaAl2Si2O8）,augite（Ca（Mg,Al,Fe）Si2O6）,hematite（Fe2O3）and quartz（SiO2）,four kinds of crystals are precipitated from the glass phase to form the skeleton structure of the foamed ceramics,thereby improving the properties of the foamed ceramics.The foamed ceramics were prepared by using titanium-bearing blast furnace slag and shale slag as raw materials.This chapter mainly explored the influence of blast furnace slag content,sintering temperature,holding time and heating rate on the properties and pore structure of the foamed ceramics.The experimental results could get to prove the best foamed ceramics sample was obtained the titaniumcontaining blast furnace slag content is 20%,the shale slag content is 80%,the addition amount of SiO2 powder is 15%,the addition amount of ball clay is 10%,the addition amount of SiC is 0.4%,and the addition amount of Na2B4O7 is 2%,NaPO3 addition amount is 1%,sintering temperature is 1110℃,holding time is 60 min,and heating rate in high temperature zone is 3℃/min,The best sample exhibited the excellent comprehensive properties:the porosity of 86.6%,bulk density of 0.316 g·cm-3,compressive strength of 3.528 MPa,thermal conductivity of 0.152 W/（m·K）.After testing,the crystalline phases of the best foamed ceramics are mainly composed of plagioclase（（Ca,Na）（Si,Al）₄O₈）,quartz（SiO₂）and diopside（CaMgSi₂O₆）.