Industry Knowledge of Mullite Refractory Brick

Mullite refractory brick is an essential material mainly used in high-temperature furnaces because of its exceptional properties. It is made by combining alumina and silica. This article elaborates on the classification, technical parameters, and production process of mullite refractory brick.

Mullite refractory brick is classified according to the percentage of alumina and silica that it contains. The classification is in three main groups, which are low purity, medium purity, and high purity. Low purity mullite refractory brick contains less than 60% alumina, medium purity contains 60-70% alumina, and high purity contains more than 70% alumina.

The technical parameters that define the quality of mullite refractory brick include density, compressive strength, modulus of rupture, thermal conductivity, linear shrinkage, and chemical composition. The density of the brick ranges from 2.3-2.6 g/cm³. A high-density brick has a greater ability to resist high temperatures, while a low-density brick is more porous, making it ideal for insulating furnaces. The compressive strength of mullite refractory brick ranges from 50-200 MPa. A brick with a higher compressive strength can withstand greater pressure. The modulus of rupture measures the ability of the brick to resist bending stress. The higher the modulus of rupture, the more resistant the brick to breakage. The thermal conductivity of mullite refractory brick ranges from 1.5-2.5 W/mk. A low thermal conductivity rating makes it a poor conductor of heat, and outstanding insulating capabilities. The chemical composition is essential to ensure suitability for specific applications.

The production of mullite refractory brick begins with the selection of high-quality raw materials, which are typically fused Mullite grains and high-silica bauxite. The ingredients are mixed in precise proportions and sintered in a high-temperature kiln. The firing temperature ranges from 1450°C-1800°C, depending on the desired properties of the final product. The process ensures the components are fused together to create a dense, durable, and homogenous product.

Mullite refractory brick is an indispensable material for industries that require high-temperature furnaces. The classification, technical parameters, and production of this material are crucial aspects that ensure the brick's suitability for specific applications. The selection of high-quality raw materials and precise control in the production process guarantee the high-quality standards expected from mullite refractory brick.