7. Fused zirconium corundum bricks/ Fused Cast AZS Brick

Fused zirconium corundum bricks belong to the Al2O3-ZrO2-SiO2 system (AZS bricks for short). According to the ZrO2 content, they can be divided into three levels: 33%, 36%, and 41%. 

For specific parameters of AZS Bricks, please click on the product homepage to view.

Compared with fused mullite bricks, fused zirconium corundum bricks have better resistance to glass liquid erosion. The main reasons are:

① The main crystal phases in zirconium corundum bricks are corundum and baddeleyite coexisting in a dense manner. Both crystal phases have good erosion resistance.

② The glass phase in zirconium corundum bricks is filled between the above crystal phases. After being eroded by high-temperature glass liquid, this glass phase generates a sodium feldspar glass with higher viscosity. Because a certain amount of ZrO2 is melted in it, the viscosity is greater. This layer of high-viscosity glass remains on the surface of the brick and is not easy to diffuse, protecting the brick body. The erosion resistance of fused zirconium corundum bricks increases with the increase of ZrO2 content. The melting temperature of ZrO2 is as high as about 2700℃, and it has high resistance to acid, alkali and glass liquid.

Fused zirconium corundum bricks are not only used in places with high temperature and severe corrosion in contact with glass liquid, but also widely used in the upper structure of glass melting furnace.

8. Fused corundum bricks

Fused corundum bricks a-b-Al2O3 (94.5% 96.5%) are made of high-purity alumina as raw materials, with a small amount of soda ash introduced and melted at 2000-2200℃. The crystal structure is composed of 45%-55% a-Al2O3 and 45%-60% b-Al2O3 phases. Since a large amount of b-Al2O3 is interwoven between a-Al2O3 crystals, the original a-Al2O3 tubular microstructure becomes a flaky structure, and the crystals are much smaller than when they exist alone. Therefore, its corrosion resistance is second only to a-Al2O3, while the heat deformation resistance of the brick body is greatly improved. Therefore, it has become the best choice for the refractory material of the channel pool wall and the clarification area of ​​the melting part.

The erosion of refractory materials at high temperatures is: AZS-41#>AZS-36#>AZS-33#〉a-b-Al2O3. This is because the main crystal phases in fused zirconium corundum bricks are densely coexisting corundum (a-Al2O3) and baddeleyite (ZrO2), and both crystal phases have good corrosion resistance. The corrosion resistance of fused zirconium corundum increases with the increase of ZrO2 content. Due to the high strength requirements of the foot bricks, and considering that the volatiles of the glass liquid are easy to gather here, the foot bricks of the melting furnace should choose 33# fused AZS bricks. Similarly, the corners of the pool wall are more affected by the erosion of the glass liquid, and the volatiles of the glass liquid and alkali vapor are more likely to gather here. Generally, fused bricks with higher ZrO2 content should be selected, and 41# fused AZS bricks are the best.

9. Zirconium-containing refractory bricks

Zirconium-containing refractory products are refractory products made of zirconium oxide (ZrO2) and zircon (ZrSiO4) as raw materials. Zirconium oxide series products, zircon series products, zircon mullite and zirconium corundum products all belong to this type of products. According to different production processes, zirconium-containing refractory products are divided into sintered products, cast products and unfired products. Zirconium-containing refractory products have the characteristics of high melting point, low thermal conductivity, good chemical stability, especially good corrosion resistance to molten glass.

The properties of zirconium-containing refractory materials depend on the properties of ZrO2. The melting point of dense and stabilized zirconium oxide is 2677℃, and the operating temperature is up to 2500℃. The bulk density fluctuates between 4.55.5g/cm3 due to the purity of the raw materials and the different manufacturing methods. The bulk density of dense zirconium oxide products can reach 5.75g/cm3. Zirconia products have high mechanical strength, and the strength is maintained up to 13001500℃. The thermal conductivity of ZrO2 is much lower than that of all other oxide materials. This property of ZrO2 can be used to make high-temperature insulation layers.