Phase transition heat storage and self-healing mechanism of spinel-calcium aluminate composite aggregate in corundum castable

Corundum-spinel castable is a vital refractory material used in steel ladle linings. Conventional approaches for assessing the thermal shock resistance of corundum-spinel refractory are not entirely representative of the actual application scenarios. This study investigates the influence of spinel-calcium aluminate composite aggregate on the thermal shock resistance of corundum castable using supersonic frequency induction heating technology. The research uncovers how CMA aggregate enhances the thermal shock resistance of corundum castable by cyclic thermal shock tests under varying operational conditions. Results reveal that the incorporation of CMA aggregate led to significant improvements in cold crushing strength and strength retention ratio following thermal shocks. The observed enhancement predominantly stems from the presence of CA/CA₂ phase within the CMA aggregate, which undergoes a solid-liquid phase transition at high temperatures, enabling the absorption and retention of substantial heat and aiding in the repair of microcracks within the materials and at the interfacial regions.