Mullite brick

Mullite bricks are refractory materials primarily composed of high-alumina bauxite clinker, with mullite (3Al₂O₃·2SiO₂) as the main crystalline phase.  They are manufactured by adding a small amount of clay or raw bauxite as a binder, followed by shaping and sintering.  The alumina content is generally between 65% and 75%.  They possess excellent high-temperature performance, a low coefficient of thermal expansion, strong corrosion resistance, and good thermal shock resistance, and are widely used in industrial furnaces such as blast furnace hot blast stoves, glass melting furnaces, dry quenching furnaces, and heating furnaces. 

一.Product Classification

1. Sintered Mullite Bricks: These are formed using natural mullite minerals or precisely formulated raw materials as the base, through a high-temperature sintering process. Their core advantages lie in their dense microstructure and low porosity, combined with excellent wear resistance and thermal shock resistance, making them suitable for working conditions with significant temperature fluctuations.

2. Fused Mullite Bricks: These are made from high-purity fused mullite as the raw material, directly cast after high-temperature melting.  These products have extremely low impurity content, exhibiting a low coefficient of thermal expansion, good dimensional stability, and superior corrosion resistance and slag erosion resistance, making them suitable for harsh high-temperature corrosive environments. 

3. Lightweight Mullite Bricks: These are low-density refractory bricks prepared from a mullite raw material system with the addition of lightweight components such as foaming agents, using a special process.  Their outstanding characteristics include low thermal conductivity and excellent thermal insulation, although their mechanical strength is relatively low. They are more suitable for applications requiring high insulation and low stress.

4. Zirconia-Mullite Bricks: These are high-performance composite material bricks based on a mullite matrix, formed by compounding with zircon. The introduction of zircon significantly improves the high-temperature performance of the product, resulting in superior corrosion resistance and crack resistance, enabling them to withstand extreme high temperatures and the erosion of complex media.

二. Physical And Chemical Indicators

三. Application:Due to its excellent properties, mullite brick is widely used in the following fields:

1. Iron and Steel Industry

Used as lining materials for blast furnaces, hot blast stoves, ladles, and heating furnaces, possessing excellent slag resistance and high-temperature performance.  Used in suspended and opening areas of hot blast pipes in hot blast stoves, vertical pipes and high-temperature straight pipes, surrounding areas, and temperature-stable sections; different grades of mullite bricks are used in different areas; also used in areas of torpedo ladles subjected to molten iron impact and slag line areas.

2. Cement Industry

Applied to high-temperature areas of cement kilns, such as the transition zone and burning zone, exhibiting good high-temperature resistance and chemical corrosion resistance.                  

3. Glass Industry

Used for the roofs, breast walls, and other high-temperature components of glass melting furnaces, providing good resistance to glass melt corrosion.  Also used in the main material channels, regenerator chambers, and clarifying tank walls of glass furnaces.

4. Ceramic Industry

Used as a high-temperature refractory material in the furnace linings and kiln furniture of ceramic kilns.  Used in the manufacture of saggars and kiln furniture in the ceramic industry.

5. Non-ferrous metal smelting

Used as furnace lining in smelting furnaces for non-ferrous metals such as aluminum and copper, exhibiting excellent corrosion resistance and thermal shock resistance.

6. Petrochemical industry

Applied as lining in high-temperature equipment such as cracking furnaces, conversion furnaces, and carbon black furnaces.

7. Building materials industry

Mullite bricks can be used as lining in cement and lime rotary kilns. In cement kilns, mullite bricks are used in high-temperature areas such as preheaters, kiln heads, transition zones, and firing zones, and can withstand high loads and acidic atmosphere corrosion. In glass kilns, mullite bricks can withstand high temperatures and the erosion of molten glass in areas such as melting furnaces, cooling channels, heating furnaces, and regenerators, extending the service life of the kiln.