Corundum mullite  refers to refractory products made of high purity or purer raw materials.   Corundum mullite refractory  refers to a high alumina refractory product composed of corundum and mullite main crystal phases. The refractory bricks made of mullite granules as aggregate has good thermal shock resistance, but the corrosion resistance is slightly poor. The corundum sand as the aggregate product has good corrosion resistance, but the thermal shock resistance is slightly poor.