The difference between mullite bricks and mullite insulation bricks

Mullite bricks and mullite insulation bricks are significantly different in composition and application scenarios.

Mullite bricks and mullite insulation bricks differ mainly in the following aspects:

1. Composition and definition

Mullite bricks: These are high-alumina refractory materials with mullite as the main crystalline phase, and the alumina content is usually between 65% and 75%. In addition to mullite, they may also contain glass phase, quartz (when the alumina content is low) or corundum (when the alumina content is high).

Mullite insulation bricks: These are refractory materials with excellent thermal insulation properties, which are usually achieved by introducing pores or using special production processes to reduce density. The composition of mullite insulation bricks is similar to that of mullite bricks, but the differences in production process and microstructure lead to their superior thermal insulation properties.

2. Performance characteristics

Mullite bricks: The refractoriness exceeds 1790℃, and the load softening temperature is generally between 1600℃ and 1700℃. The compressive strength at room temperature is generally between 70 and 260MPa.

Mullite insulation bricks: The refractoriness can reach above 1800℃, and the insulation performance is excellent. It can greatly reduce the thickness of the furnace wall, and the density is small, which effectively reduces the weight of the furnace body. Due to the excellent insulation performance of mullite insulation bricks, they are widely used in hot blast furnaces, glass crucibles and other industrial kilns that require efficient insulation.

3. Production process

Mullite bricks: There are two main production methods: sintering and electric melting. Sintered mullite bricks are made of high-alumina bauxite clinker as the main raw material, with a small amount of clay or raw bauxite as a binder, and are formed and fired; electric fused mullite bricks are made of high-alumina materials, industrial alumina, and refractory clay as raw materials, with charcoal or coke powder as a reducing agent, and are formed and made by reduction electric melting.

Mullite insulation bricks: Made by special production processes, such as introducing pores, foaming methods, adding burnout additives or gasification methods, to reduce density and enhance insulation performance.

Necessity of Mullite Bricks and Mullite Insulation Bricks

Hongtai Refractory has been deeply involved in refractory materials for many years and is an experienced manufacturer and supplier. We can develop targeted application solutions according to your needs and produce mullite insulation bricks of required sizes and shapes. These mullite insulation bricks are suitable for various high-temperature environments, such as hot blast furnace tops, blast furnace bodies and bottoms, glass melting furnace regenerators, ceramic sintering kilns, dead corner linings of petroleum cracking systems, etc.

If you have mullite insulation bricks or refractory related needs, please contact us. Hongtai Refractory will provide timely services, develop comprehensive delivery plans, and provide you with high-quality refractory materials at competitive factory prices.