Research on application of kyanite in plastic refractory

Effect of kyanite addition on properties of plastic refractories that based on Chinese calcined flint clay were investigated with the Chinese calcined flint clay as raw materials, aluminum sulfate and fireclay as binding systems. After 24 h curing after demoulding and another 24 h curing at 110°C, the specimens were heat-treated at 1000, 1300 and 1500°C for 3 h, respectively. The permanent linear change, bulk density, modulus of rupture, clod crushing strength, thermal expansion coefficient and thermal shock resistance were examined. The results show that the shrinkage of plastic refractory decreased with increasing kyanite addition after heat-treated at 1000 and 1300°C, and its expansivity increased with increasing kyanite addition after heat-treated at 1500 °C. The strength can be increased when kyanite was added into the plastic refractory. The thermal expansion coefficient and the expansivity were increased, and the shrinkage can be reduced at high temperature when kyanite addition was more than 10%. On the condition of this experiment, the thermal shock resistance of plastic refractory was the best when kyanite addition is w(kyanite)=10%.