Alkali Refractory Materials
Alkali refractory materials are a kind of refractory materials that can withstand high temperatures and stresses, and can maintain integrity in the presence of alkalis or ammonia. Alkali refractory materials are mainly used in the glass industry, waste incineration plants and boiler and furnace linings. Alkali refractory materials are classified as high-temperature and low-temperature alkali refractory materials. High-temperature alkali-refractory materials are mainly used as outer linings or protective shields of glass furnaces, crucibles and hot vapour-transport ducts. Low-temperature alkali-refractory materials are mainly used in waste incineration systems, thermal and insulation materails, glass furnaces and protective coating applications.
Alkali refractory materials are mainly made from high-grade refractory clays, silica and alumina, which are then blended with magnesia and magnesium aluminate, usually in the form of fused silica, magnesia–alumina spinel and alumina–magnesia spinel. These materials are formed into bricks, tiles, shapes and other components, which are then cured and formed by various processes, such as calcining, glazing and firing. The choice of alkali refractory material depends on the application, the temperature and the stress to which it will be exposed.
Alkali refractory materials are resistant to molten glass, molten phosphate and molten iron. They are also resistant to alkaline materials such as silicates, phosphates and sulphates. Alkali refractory materials can also resist high temperature shocks and flames and can withstand high temperatures up to 1400°C. They are also highly resistant to chemical corrosion and abrasion, which helps to maintain the performance of alkali refractory materials over long periods of time.
In addition to the properties listed above, alkali refractory materials are non-wetting, which means that molten glass does not adhere to their surface, preserving their integrity and their ability to withstand the molten materials. Alkali refractory materials also possess excellent thermal shock resistance, good electrical insulation properties, thermal stability and good processability.
Alkali refractory materials have wide applications in many different industries. In the glass industry, alkali refractory materials are used extensively for furnace linings, furnace walls, furnace floors and insulation bricks. They are also used in ceramic glass melting, heat recovery systems, flue-gas waste heat recovery, ceramic glass casting and crystal glass melting.
In addition, alkali refractory materials are used in waste incineration applications, where they are used to line furnace walls and floors, and in industrial boilers, they are used as boiler tubes, grate bars and water walls. Alkali refractory materials are also used in manufacturing of petrochemical equipment, such as distillation columns and storage vessels, as well as in the construction of chimney flues.
Overall, alkali refractory materials have exceptional properties, making them suitable for a wide range of industries and applications. They possess superior mechanical and physical properties, as well as excellent corrosion and thermal shock resistance. The fact that they are non-wetting and have good processability makes them an ideal choice for furnace linings, furnace walls and insulation bricks. Their high thermal stability and electrical insulation properties make them a good choice for waste incineration applications, petrochemical equipment and chimney flues. As such, alkali refractory materials are an essential material for many industries.
