Properties of foamed ceramics prepared from coal gangue/
In order to utilize coal gangue and steel slag with high added value,foamed ceramics were pre-pared using coal gangue as the main starting material,and steel slag as the auxiliary starting material,adding appropriate amounts of flux(talc and potassium feldspar)and foaming agent silicon carbide.The effects of the steel slag addition(equivalent replacement of coal gangue,5%,10%,15%,20%,25%,30%,and 35%,by mass)and flux addition(fixing the total addition of talc and potassium feldspar at 20 mass%,replacing potassium feldspar with talc in the equal amount of 0,5%,10%,15%,and 20%,by mass)on the physical properties,microstructure and phase composition of the foamed ceramics were studied.The re-sults show that:(1)with the increasing steel slag addition,the SiO2 content in the skeleton structure decrea-ses,the content of CaO,MgO and other oxides increases,and the viscosity decreases;excessive steel slag is not conducive to the formation of moderate-size and uniformly distributed pores due to the low SiO2 content;the steel slag addition shall not exceed 30%;(2)the influence of talc and potassium feldspar flux on the foamed ceramics is mainly to change the contents of alkali metal oxides,as well as Al2O3 and SiO2 which constitute the ceramic skeleton;(3)the optimal foamed ceramic formulation is:m(coal gangue)∶m(steel slag)∶m(potassium feldspar)∶m(talc)=50∶30∶10∶10,extra-adding 0.1 mass%SiC.