Mullite brick (3Al2O3 - 2SiO2) is high alumina refractory material with the main crystal phase as the raw materials. General alumina content is between 65%-75%. Mineral composition in addition to the mullite, it contains a small amount of glass phase and cristobalite in the lower alumina containing brick; and also a small amount of corundum in high alumina containing brick. The mullite brick with characteristics of high refractoriness which can reach to more than 1700℃, the apparent initial softening temperature is between 1600-1700℃, the cold crushing strength is between 70-260MPa, good thermal shock resistance, and can be divided into sintered mullite brick and fused mullite brick. Sintered mullite brick with the bauxite clinker as the main raw materials, adding some clay or raw bauxite as binding agent, produced by molding and sintering. Fused mullite brick with high bauxite, alumina and refractory clay as raw material, adding charcoal or coke fines as reducing agent, manufactured by reduction of fused method after forming. The crystallization of fused mullite is bigger than the sintered mullite, the thermal shock resistance is better than the sintered products. The high temperature performance is mainly depend on the content of alumina and the uniformity of mullite phase and glass distribution.

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