This issue we continue to introduce mullite brick performance.
Fused mullite bricks produced by the sintering method are mainly used in glass kilns. This brick has high mechanical strength and high deformation temperature under load, high density, low porosity, and much crystalline phase content, and there is no abnormal phenomenon on the thermal expansion curve. However, when such substances are in contact with a large amount of alkali substances at high temperatures, mullite is unstable and easily decomposes, which reduces the stability of such refractory materials to a certain extent. In addition, the final properties of fused mullite bricks produced from fused mullite materials of different purity will vary. Even fused mullite of the same chemical purity (such as high-purity products), but produced through different fused process , the refractory bricks will also have different properties.
Mullite bricks should not be in contact with alkaline substances when the temperature is above 1450℃, otherwise mullite will decompose. In a reducing atmosphere above 1370℃, mullite will also decompose, and part of SiO2 becomes gaseous SiO2 leaving the brick body. When the temperature is higher than 1650°C, mullite will decompose even if it is not a reducing atmosphere but at a lower oxygen content. It can be seen that the combustion temperature directly affects the forming of mullite bricks.
