The refractory range of high alumina bricks fluctuates widely, generally 1770~2000℃, which is mainly affected by the content of Al2O3, and increases with the increase of the content of Al2O3 in the product. At the same time, the refractoriness is also affected by the content and type of impurities, which is related to the mineral phase structure of the product. The deformation temperature of high alumina bricks under load softening is greater than 1400℃, and increases with the increase of Al2O3 content. For products with Al2O3 content less than 71.8%, the softening temperature under load depends on the quantity ratio of mullite and glass phase, and increases with the increase of mullite quantity.
The amount and nature of the glassy phase have a significant effect on the softening point under load. When the Al2O3 content is 71.8%~90%, it is mullite and corundum products. With the increase of Al2O3 content, the amount of glass phase remains basically unchanged. Although corundum increases, mullite decreases; therefore, the softening temperature under load increases. Not obvious. After the Al2O3 content exceeds 90%, with the increase of Al2O3 content, the number of glass phases decreases, and the softening temperature under load increases significantly, from 1630 °C to 1900 °C, and the softening temperature under load increases with the increase of Al2O3 content.
The thermal conductivity of high alumina bricks decreases with increasing temperature. When the content of Al2O3 in the high alumina brick is higher, the more mullite and corundum crystals, the more obvious the tendency of thermal conductivity to decrease with the increase of temperature. But above 1000 ℃, its decreasing range decreases.
