A class of inorganic nonmetallic materials with a refractoriness less than 1580 degrees C. The refractoriness refers to the centigrade temperature of the refractory cone specimen in the absence of weight, to resist the effect of high temperature and not to soften the molten centigrade. However, the refractory is not fully described by the definition of refractoriness, and 1580 is not absolute. The material now defined as a material that allows its physical and chemical properties to be used in a high temperature environment is called refractories. Refractories are widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, power and other industrial fields. They are the largest in metallurgical industry, accounting for 50% to 60% of the total output.