Lightweight refractories have the advantages of low density, low thermal conductivity, and small line changes after refiring, which can fully reduce the construction cost of thermal equipment such as industrial kilns and reduce the heat loss of kilns. In the insulation layer of high-temperature kiln equipment be widely used. Among them, alumina hollow ball is an ideal lightweight aggregate, which has important practical significance for the use of alumina bubble bricks and castables made of alumina hollow balls.
Alumina hollow ball bricks use alumina hollow balls as the main material, corundum superfine powder as additives, and organic matter as binders. alumina bubble bricks are fired in a high-temperature kiln at 1750°C after forming and drying, and belong to the category of lightweight corundum insulation bricks.
The 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°C. Alumina bubble brickshave excellent high temperature resistance and thermal insulation properties, and can be directly used as the working lining of high temperature kilns, and have obvious effects on reducing the weight of the furnace body, improving the structure, saving materials and energy.
The research and development of alumina bubble bricks and their application in industrial kilns and equipment have largely improved some of the shortcomings of lightweight insulation materials. Although the refractory bricks commonly used such as high alumina bricks, silicon carbide bricks, and clay refractory bricks have a high temperature of more than 1700°C, their thermal conductivity is too high, so they are not suitable for use as an insulation layer and can only be used as a refractory layer. The insulation layer of most kilns Insulation bricks or insulation materials are usually used, which not only increases the thickness of the masonry, but also increases the risk of use. The long-term operation of the furnace lining is not ideal. If you directly choose light insulation materials as kiln and equipment lining refractories, you need to fully consider the light insulation materials. Load softening temperature and acid and alkali corrosion resistance. However, the long-term use temperature of insulation materials generally does not exceed 1200 ° C, and the compressive strength is relatively poor, generally 3-5 MPa, and the effect of acid and alkali corrosion resistance is not ideal. Therefore, the use of lightweight insulation materials alone can be used in low-temperature kilns where there is no pressure and chemical erosion, and high-temperature kilns must be built with refractory bricks for protection.
The manufacture and production of alumina bubble bricks not only solve the problem of high thermal conductivity, but also solve the problems of use temperature and compressive strength in light-weight insulation materials. , Tungsten rod furnace, induction furnace, nitriding furnace and other equipment have been well verified.
