多孔球形莫来石基浇注料的制备及性能研究

为制备保温性能及机械性能均较优异的高温窑炉用隔热耐火材料,以多孔球形莫来石、矾土细粉、α-Al₂O₃微粉、硅微粉和Secar71水泥为主要原料,制备了多孔球形莫来石基浇注料,研究了矾土细粉掺量对多孔球形莫来石基浇注料机械性能、导热系数、抗侵蚀性能及热震稳定性的影响。结果表明,改变矾土细粉的掺量,可使多孔球形莫来石基浇注料在保持较高机械性能的基础上提高保温性、热震稳定性和抗侵蚀性能。随着矾土细粉掺量的增加,多孔球形莫来石基浇注料的机械性能变化不大,但导热系数小幅降低,抗侵蚀性能出现较大差异,热震稳定性先提高后降低。当矾土细粉掺量为28%(质量分数)时,多孔球形莫来石基浇注料的机械性能、热震稳定性及抗侵蚀性能良好,在1 000 ℃时导热系数为0.905 W·m^-1·K^-1。多孔球形莫来石基浇注料的导热系数低于中间包和钢包永久层用高铝浇注料,可替代中间包、钢包永久层用高铝浇注料以减少热损失。

Preparation and Properties of Porous Spherical Mullite-Based Castable

To prepare thermal insulation refractory for high-temperature kilns with excellent thermal insulation and mechanical properties, porous spherical mullite-based castable was prepared with porous spherical mullite, bauxite powder, α-Al₂O₃ powder, silica powder, and Secar71 cement as main raw materials. The effect of bauxite powder content on mechanical properties, thermal conductivity, corrosion resistance, and thermal shock stability of porous spherical mullite-based castable was studied. The results show that changing the content of bauxite powder can improve the thermal insulation, thermal shock stability, and corrosion resistance of porous spherical mullite-based castable while maintaining high mechanical properties. As the content of bauxite powder increases, the mechanical properties of porous spherical mullite-based castable change little, but the thermal conductivity decreases slightly, the corrosion resistance is quite different, and the thermal shock stability increases first and then decreases. When the bauxite powder content is 28%(mass fraction), the mechanical properties, thermal shock stability, and corrosion resistance of porous spherical mullite-based castable are excellent, and the thermal conductivity at 1 000 ℃ is 0.905 W·m^-1·K^-1. The thermal conductivity of porous spherical mullite-based castable is lower than that of high-alumina castable for tundish and ladle permanent layer, therefore, it can be used as a substitute for high-alumina castable for tundish and ladle permanent layer, and its heat loss can be reduced.