Lightweight refractory materials have the advantages of low density, low thermal conductivity, and small linear changes after reburning, which can fully reduce the construction cost of industrial kilns and other thermal equipment, reduce the heat loss of kilns, and are widely used in the insulation layer of high-temperature kiln equipment. Among them, bubble alumina are an ideal lightweight aggregate, which has important practical significance for the use of bubble alumina bricks and castables made from bubble alumina.

Bubble alumina bricks are mainly made of bubble alumina, with ultrafine corundum powder as an additive and organic matter as a binder. Bubble alumina bricks are formed and dried, and then fired in a high-temperature kiln at 1750 ℃, belonging to the category of lightweight corundum insulation bricks.

This material has the characteristics of low thermal conductivity and high compressive strength of insulation bricks. It is a lightweight insulation brick that can be used normally at 1700 ℃.Bubble alumina bricks have excellent high-temperature resistance and insulation performance, and can be directly used for the working lining of high-temperature kilns, achieving significant results in reducing furnace weight, transforming structure, saving materials and energy.
The research and development of bubble alumina bricks and their application in industrial kilns and equipment have greatly improved some of the shortcomings of lightweight insulation materials. Although commonly used refractory bricks such as high alumina bricks, silicon carbide bricks, and clay refractory bricks have a fire resistance exceeding 1700 ℃, their thermal conductivity is too high to be used as insulation layers and can only be used as refractory layers. Most kilns usually use insulation bricks or materials for insulation layers, which not only increases the thickness of the masonry but also increases the risk of use, resulting in unsatisfactory long-term operation of the furnace lining, If light insulation materials are directly selected as refractory materials for kiln and equipment lining, it is necessary to fully consider the load softening temperature and acid alkali corrosion resistance of light insulation materials. The long-term use temperature of insulation materials generally does not exceed 1200 ℃, and their compressive strength is relatively poor, usually between 3-5 MPa, which results in unsatisfactory acid and alkali corrosion resistance. Therefore, using lightweight insulation materials alone can be used for masonry in areas where there is no pressure or chemical erosion in low-temperature kilns, while high-temperature kilns must be equipped with a protective layer of refractory bricks.

The manufacturing and production of bubble alumina bricks not only solve the problem of high thermal conductivity, but also solve the problems of temperature and compressive strength in the use of lightweight insulation materials. They have been well verified in high-temperature and energy-saving inverted flame kilns, shuttle kilns, molybdenum wire furnaces, tungsten rod furnaces, induction furnaces, nitriding furnaces, and other equipment.