High aluminum firebrick is a kind of refractory product with Al2O3 content of more than 48% in aluminum silicate refractory. According to the composition of the main minerals in the products, the high alumina refractory products are divided into four categories: mullite - corundum, corundum - mullite, mullite and corundum. If according to the level of AL2O3 content, the common use of high aluminum bricks are divided into three levels, that is, a grade AL2O3> 65%; Second grade AL2O355% ~ 65%; Tertiary product AL2O348% ~ 55%.

The characteristics of high aluminum brick are as follows:

(1) The resistance of high aluminum refractory brick to high temperature, its refractoriness in aluminum silicate refractory is relatively high, with the increase of AL2O3 content in the product and the refractoriness is improved, generally not less than 1750 ~ 1790℃. If the AL2O3 content is greater than 95% of corundum products, its refractoriness can be as high as 1900 ~ 2000℃.

(2) The load softening temperature of high aluminum refractory brick decreases with the increase of SiO2 and metal oxide content in the product, and the load softening temperature of high aluminum brick is generally 1420 ~ 1530℃. For corundum products with AL2O3 content greater than 95%, the load softening temperature is above 1600℃.

(3) High-aluminum firebrick has the performance of resisting various slag, because the AL2O3 content in the product is high and neutral, so it has a strong corrosion resistance to acidic or alkaline slag.

(4) High-aluminum refractory brick has thermal shock resistance, corundum and mullite two crystals coexist in its products, and the linear expansion coefficient of corundum is larger than the linear expansion coefficient of mullite, so when the temperature changes due to the difference in the expansion of the product and stress concentration, so the thermal shock resistance of high-aluminum brick is poor, and the general water cooling times are only 3 to 5 times.

(5) The reburning line of high aluminum refractory brick changes according to the degree of burning of the product. If the burning temperature is sufficient, the burning Yan is sufficient, the volume is stable, and the heavy burning line changes little. On the contrary, due to recrystallization within the product, residual shrinkage will occur.