Introduction of corundum mullite bricks

Composition of corundum mullite bricks

Corundum and mullite bricks are made of corundum and mullite as the main raw materials, and are fired at high temperature in an oxidizing atmosphere by adding an appropriate amount of alumina, silica ultrafine powder and additives. The content of AL2O3 is 72%~90%.

Production process of corundum mullite brick

The corundum mullite brick body is formed by a 300t friction press, and the body density is 2.7g/cm3. The body is dried in a tunnel dryer. The inlet temperature is 40~50℃, the highest drying temperature is 130℃, the drying time is 48h, and the body moisture is not more than 1.5%. The product is fired in a tunnel kiln, the firing temperature is 1550℃, and the holding time is 10h.

Method for forming corundum mullite brick

(1) Refractory products with complex shapes and larger sizes are rammed or vibrated by air hammer.

(2) Ordinary products or standard sizes can be formed by semi-dry high pressure forming.

(3) Special-shaped pure or special products need to design molds and adopt isostatic pressing.

The physical properties of corundum mullite bricks

The high-temperature main crystal phases of corundum mullite bricks are corundum and mullite. The crystals of corundum are short columnar and barrel-shaped, and they are not interspersed or staggered in the refractory structure. Interlaced columnar crystals of mullite are embedded between the corundum crystals to effectively prevent the slip of the corundum crystals and obtain a stable structure. Because the crystal structure is more stable, it is more conducive to the excellent performance of mullite or mullite and corundum, such as melting point: mullite 1870℃, corundum 2050℃, the eutectic temperature of the two is higher, 1840℃, which is beneficial Improvement and enhancement of high temperature performance of materials.

Advantages and characteristics of corundum mullite bricks

(1) High temperature resistance, high refractory temperature and high load softening temperature.

(2) Chemical resistance, strong resistance to acidic solution or molten slag.

(3) Antioxidant. It is not easy to react with O2, H2, CO and other gases.

(4) Good thermal stability, stable volume at high temperature, and not easy to expand or contract.

(5) Good thermal shock resistance, resistance to rapid cold and heat, and not easy to peel off.

(6) High compressive strength at room temperature, and it is not easy to wear when handling or unloading.

Uses of corundum mullite bricks

Corundum mullite bricks can directly contact the flame, resist peeling, and resist high temperature. It can be used as the heat insulation lining of high-temperature industrial furnaces and the working layer of other industrial high-temperature kilns. It is mainly used in petrochemical industry and large and medium-sized synthetic ammonia gasification. Furnace and magnetic materials, gas furnace materials, high-temperature industrial furnace supporting facilities materials.