Effect of Zirconium mullite addition on thermal shock resistance of corundum refractory castable

Corundum refractory castables were prepared by using fused corundum, zirconium mullite and α-Al2O3 micropowder as the main raw materials with calcium aluminate cement as binder. The effects of zirconium mullite addition (mass fractions of 0, 3%, 6%, 9%) on the physical properties, phase composition and microstructure of corundum refractory castables were investigated.   The results show that :
1) With the increase of zirconium mullite addition, the physical properties of the corundum refractory castables after drying at 110 °C are not changed much. The bulk density and normal temperature flexural strength of the samples after 1600 °C are increased first. After the trend of reduction. Due to the formation of calcium aluminum yellow feldspar, the sample is 1500 ° C × 0.5
h high temperature flexural strength decreased significantly; (2) Due to the phase transformation and toughening effect of ZrO2, the introduction of zirconium mullite improves the thermal shock resistance of corundum refractory castables. Based on various properties, it is considered that the optimum mass fraction of zirconium mullite is 3%.