What Are Fused Cast Refractories

Fused cast refractory is named by its manufacturing method. The term Fused Cast refers to a manufacturing process in which the ceramic bonding is obtained by the solidification of a mixture which has been melted in an electric furnace and cast in liquid state into molds.
Fused cast refractories have been known and used for many years. Such refractories have presented many advantages in certain uses over the older type of refractory products. Fused cast refractories are denser and more corrosion-resistant than fired and unfired bonded refractories. Fused cast materials, especially the fused cast AZS, are the preferred grades in contact with glass melts.
Fused cast refractories usually have a lower apparent porosity (1-3%), a compression strength and a high deformation temperature. They have great corrosion resistance to melts such as glass and molten metal oxides due to compact structure and closed pores. They also offer the lowest blistering potential in many applications.
Fused cast refractories are manufactured by melting mixtures of raw material of the desired composition in an electric furnace at a temperature exceeding 2000°C, casting the melt into moulds where it solidifies and cooling the molten refractory material to form a solidified refractory. High density, small or large shapes are obtained. When appropriate, a finish is made by grinding with diamond tools.
Many different compositions for fused cast refractories have been developed, such as Fused cast AZS, Fused cast alumina and Fused cast high zirconia block.
Fused cast AZS block is the most widely used material both in glass contact and superstructure of glass melting furnaces due to its good corrosion resistance to melten glass and almost no pollution to glass liquid.
Due to good resistance to alkali vapors, fused cast alumina block is the best choice for the downstream part of superstructures of glass furnaces. the most widely used grades are alpha-beta fused cast alumina block and beta fused cast alumina block.
Fused cast high zirconia block has been frequently used for a portion of contact with molten glass of a glass melting furnace which is required to have high quality, such as substrate glass for a flat panel display.
Besides glass industry, Fused cast refractory materials are also used in many other industries such as iron & steel, aluminum, petrochemistry or wear resistant applications.