Industrial grade alumina is a kind of transition phase alumina, which has strong activity, can be dissolved in acid or alkali solution, and has strong water absorption in the air. It has hydraulic properties and can react with water to produce high-strength aluminum hydroxide gel. Because this product is pure alumina phase, with less impurities, high purity, and no eutectic phase, it can be used as a binder for high-temperature refractory (low cement or no cement) castables to improve the refractoriness and slag resistance of refractory products. It is corrosive and has properties such as no drop in strength at medium temperature. Used in many large domestic iron and steel enterprises, it significantly increases the life of refractory materials such as ladle and iron ditch, and reduces costs.