Selection of Electrofused Corundum Bricks in Float Glass Furnaces

A glass furnace is a thermal equipment for glass melting constructed with refractory materials. The service efficiency and lifespan of a glass furnace largely depend on the types and quality of refractory materials. The development of glass production technology is significantly reliant on advancements in refractory material manufacturing technology. Therefore, the rational selection and use of refractory materials are crucial in the design of glass furnaces. To achieve this, two key points must be mastered: first, the characteristics and applicable parts of the selected refractory materials; second, the service conditions and corrosion mechanisms of each part of the glass furnace.

Electrofused corundum bricks are produced by melting alumina in an arc furnace, casting it into a specified mold, annealing for heat preservation, and then processing it to obtain the required product. The general production process involves using high-purity calcined alumina (over 95%) and a small amount of admixtures. The mixture is fed into an arc furnace, melted at a high temperature above 2300°C, cast into a pre-prepared mold, annealed for heat preservation, and then removed. The extracted blanks are cold-processed, pre-assembled, and inspected to become qualified finished products.

Electrofused corundum bricks are classified into three types based on the crystalline form and quantity of aluminum oxide:

1. The first type is dominated by α-Al₂O₃ as the main crystalline phase, known as α-corundum bricks.
2. The second type has approximately equal contents of α-Al₂O₃ and β-Al₂O₃ crystalline phases, referred to as αβ-corundum bricks.
3. The third type is dominated by β-Al₂O₃ crystalline phase, called β-corundum bricks.

In float glass furnaces, the commonly used electrofused corundum bricks are the second and third types, namely electrofused αβ-corundum bricks and β-corundum bricks.