Fused corundum bricks are made by melting alumina in an electric arc furnace and casting it into a specified mold of a specific shape. After annealing and heat preservation, they are processed by diamond grinding tools to obtain the required corundum brick products. Rongsheng’s fused corundum bricks are mainly used as refractory bricks for glass kilns. α-β corundum bricks for glass kilns are resistant to glass liquid erosion and can effectively extend the service life of the glass kiln lining.

Rongsheng Fused Corundum Bricks Types

Rongsheng refractory manufacturers’ fused corundum bricks are divided into three types according to the different forms and quantities of alumina crystals. The first type is mainly α-Al2O3, called α corundum bricks. The second type is mainly β-AI2O3 and β-Al2O3 crystal phases, with a content of basically 1:1, and a slightly higher α phase content, called a-β corundum bricks. The third type is mainly β-AI2O3 crystal phase, called β corundum bricks.

As the name suggests, fused α-β corundum bricks for glass kilns are mainly used as linings for glass kilns. The fused α-β corundum bricks are mainly α-AI2O3 and β-AI2O3 crystal phases, with a content of about 50% each, and the product is densely crystalline. Below 1350 degrees Celsius, it has excellent corrosion resistance to glass liquid. Therefore, it is widely used in the working pool and later parts of glass kilns, and is usually used in chutes, lip bricks, gate bricks, etc.

Fused α-Al2O3 Brick

α-Al2O3 is corundum, which is the only stable crystal of alumina at high temperature. It is a rhombohedral or plate-like crystal belonging to the hexagonal system. The density is 3.99-4.00g/cm3, the melting point is 2050℃, and the Mohs hardness is 9. When it crystallizes, its volume shrinks by about 25%. The fused α-Al2O3 brick is mainly composed of α-corundum, a tight and solid fine-grained structure entity. There is no glass phase in the composition, only a small amount of β-Al2O3, which exists mainly to improve its structure. There are generally two types, one containing 99%-99.5% Al2O3, about 5%-8% β-Al2O3 phase, and 92%-95% α-AL2O3 phase, with a volume density of about 3.50g/cm3. It is mainly used in glass melting furnaces and is suitable for melting borosilicate glass, opalescent glass, and melts containing sulfates. However, its high-temperature corrosion resistance is slightly poor. At a high temperature of 1600℃, its resistance to glass liquid corrosion will decrease rapidly. Therefore, some borosilicate glass kilns tend to use fused quartz bricks.

Fused α-β Corundum Brick

The main component is Al2O3 (containing 94.5%-96.5%), and the crystal structure consists of 45%-55% α-Al2O3 phase and 45%-60% β-alumina phase. Because a large amount of β-Al2O3 is interwoven between α-Al2O3 crystals, the original tubular microstructure of α-Al2O3 becomes a flaky structure, and the β-AL2O3 crystal is much smaller than when it exists alone, and the overall structure is very compact. Therefore, its corrosion resistance becomes only slightly inferior to α-Al2O3, while the heat resistance of the brick body is greatly improved.

The bulk density of fused α-β corundum brick products is 3.15-3.30 g/cm3, containing a small amount of glass phase (about 2%), filling the pores between crystals, and the purity is very high. Because it does not pollute the glass liquid and has good resistance to glass liquid corrosion and excellent high-temperature wear resistance below 1350℃. Therefore, it is an ideal refractory material for the clarification part, cooling part, working pool, and other parts of the glass melting furnace.

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Fused β-Al2O3 Brick

β-Al2O3 is another form of alumina, with the molecular formula Na2O·11Al2O3. The relative density is 3.30-3.40, the Mohs hardness is 6, and the content of Na2O dissolved in β-AL2O3 can reach 7%. Therefore, strictly speaking, β-Al2O3 cannot be regarded as a polycrystalline form of Al2O3, it should be an aluminate group.

The white product composed of coarse and bright crystals of β-Al2O3 contains 92%-95% Al2O3, only less than 1% of the glass phase, and the product has low structural strength due to the loose lattice. Its apparent porosity is less than 15%, and the bulk density is 2.80-3.0 g/cm3. Since the density difference between β-Al2O3 and the solution is very small during melting and casting, it actually has no shrinkage pores. Because the density difference is proportional to the shrinkage volume. Rongsheng High-quality fused β-Al2O3 brick manufacturer.

Application of Rongsheng fused α-β corundum bricks

Melted α-β Al2O3 material contains about 45% α-Al2O3 and 55% β-Al2O3 phases, with an impurity phase of about 1% and pores of 2%. Melted β-Al2O3 is mainly composed of large-grained β-Al2O3, with negligible impurity phases and about 4% pores. Melted α-β or βAl2O3 materials do not contain glass phases or refractory crystal phases and have no adverse effects on glass quality. They also have good resistance to corrosion by soda-lime glass or alkali vapor below 1350℃. Therefore, α-β Al2O3 materials are widely used in cooling parts. β-Al2O3 materials are used for the upper structure of the dust-free part of the cooling part.

Application effect: After 4-8 years of use as the large crown of the all-oxygen combustion glass kiln, there is almost no significant change. α-β Al2O3 melt-cast materials can be used as crown bricks for at least 2 kiln services. Therefore, α-β Al2O3 bricks are the materials for the upper structure of all-oxygen glass kilns.

To purchase high-quality refractory bricks for glass kilns, fused corundum bricks, fused α-β corundum bricks, and refractory materials for glass kiln maintenance, please choose Rongsheng refractory Manufacturer. Contact Rongsheng for free samples and quotes.