What are the characteristics of alumina refractory

The melting point of alumina is as high as 2000 degrees, and the boiling point is more than 2900 degrees. It is a high-quality alumina refractory. Generally speaking, in addition to being non-combustible, aluminum refractory also requires flame retardant and anti-flammability. Therefore, alumina is usually included in the general fire protection material.

The refractoriness of alumina refractory is greater than 1900℃, and the softening starting point of 0.2MPa load is about 1850℃. Its limit temperature is 1950℃, and the common temperature is 1800℃. The average linear expansion coefficient of alumina at 20-1000℃ is 8.6×10-6/℃. The thermal conductivity of alumina at room temperature is half of that of metal aluminum, and the thermal conductivity decreases as the temperature increases.
The thermal shock resistance of alumina refractory depends on its microstructure and the shape and size of the product. Generally speaking, its thermal shock resistance is moderate. In short, alumina has properties such as high temperature resistance, high strength, high hardness, oxidation resistance, electrical insulation, corrosion resistance, and good air tightness. Therefore, as a special refractory material, it is widely used. The representative use of alumina refractory is to use its high temperature resistance, corrosion resistance and high strength to be used as sliding nozzles, immersion nozzles, metallurgical high-purity metals or crucibles for growing single crystals in steelmaking production, and various Structural parts of high temperature furnaces (furnace walls, furnace tubes), heat-resistant and anti-oxidative coatings, etc.