Performance Analysis of Electro - fused Corundum Bricks

Electro - fused α-β corundum bricks are composed of approximately 50% α-Al₂O₃ and 50% β-Al₂O₃. The interlaced crystallization of these two phases forms an extremely dense organizational structure. These bricks exhibit excellent resistance to strong alkali corrosion. At high temperatures above 1350°C, their corrosion resistance is slightly inferior compared to electro - fused AZS bricks. However, below 1350°C, their resistance to molten glass corrosion is comparable to that of electro - fused AZS bricks. Since they do not contain impurities such as Fe₂O₃ and TiO₂, there is very little matrix glass phase. When in contact with molten glass, few foreign substances such as bubbles are generated, ensuring that the matrix glass remains unpolluted.

With a dense crystalline structure, electro - fused α - corundum bricks demonstrate excellent resistance to glass melt corrosion below 1350°C. As a result, they are widely used in the working pool and subsequent parts of glass melting furnaces. Common application areas include launders, lip bricks, and gate bricks. Internationally, Toshiba of Japan is renowned for producing high - quality electro - fused corundum bricks.

Electro - fused β - corundum bricks are mainly composed of nearly pure β-Al₂O₃ and feature a crystalline structure with large, flat β-Al₂O₃ plates. The interlaced but coarse crystal structure leads to a relatively high porosity among electro - fused refractories, resulting in lower strength. On the other hand, they have good spalling resistance, especially showing extremely high corrosion resistance to strong alkali vapor. Therefore, they are used in the upper structure of glass melting furnaces. However, when heated in an atmosphere with low strong alkali content, upon contact with SiO₂, a reaction occurs. The β-Al₂O₃ is prone to decomposition, causing volume shrinkage, cracks, and even spalling. Hence, they are applied in areas far from where glass raw materials may disperse.

The chemical composition of both electro - fused α-β and β - corundum bricks is mainly Al₂O₃. The primary differences between them lie in the crystalline phase composition. These differences in microstructure lead to variations in physical and chemical properties such as bulk density, thermal expansion coefficient, and compressive strength.