Refractory degree is not less than 1580 ℃ of a class of inorganic non-metallic materials. The degree of fire resistance is the temperature in which the conical specimen of refractory material resists the high temperature without the load and does not soften the melt down. But only by the definition of fire resistance can not fully describe the refractories, 1580 ℃ is not absolute. It is defined as the material of the physical and chemical properties that allows it to be used in high temperature environments called refractory materials. Refractories are widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, power and other industrial fields, in the metallurgical industry, the largest amount of total production of the 50%~60%.