Refractory materials used in special occasions include high-temperature oxide materials such as alumina, lanthanum oxide, beryllium oxide, calcium oxide, zirconium oxide, etc., refractory compound materials such as carbide, nitride, boride, silicide and sulfide Etc .; high-temperature composite materials, mainly including cermets, high-temperature inorganic coatings and fiber-reinforced ceramics.
The acidic refractories use silicon oxide as the main component, commonly used are silicon bricks and clay bricks. Silica brick is a siliceous product containing more than 94% silicon oxide. The raw materials used are silica and waste silica brick. It has strong resistance to acid slag corrosion and high load softening temperature, but it is susceptible to corrosion by alkaline slag and heat resistance. Poor shock. Silica brick is mainly used in thermal equipment such as coke oven, glass melting furnace, acid steel making furnace and so on. Clay bricks use refractory clay as the main raw material and contain 30% to 46% of alumina. They are weakly acidic refractory materials. They have good thermal shock resistance, corrosion resistance to acidic slag, and are widely used.
The neutral refractories are mainly composed of alumina, chromium oxide or carbon. Corundum products containing more than 95% of alumina are high-quality refractory materials with a wide range of uses. The chromium brick with chromium oxide as the main component has good corrosion resistance to steel slag, but poor thermal shock resistance and low deformation temperature under high temperature load. Carbon refractory materials include carbon bricks,
Graphite products and silicon carbide products have low thermal expansion coefficient, high thermal conductivity, good thermal shock resistance, high temperature strength, resistance to acid and alkali and salt corrosion, especially weak acids and alkalis have good resistance to Wetting of metal and slag, light weight. It is widely used as high-temperature furnace lining material, and also used as the lining of high-pressure autoclaves in petroleum and chemical industries, which has promoted the development of the petrochemical industry.
The basic refractories use magnesium oxide and calcium oxide as the main components, and magnesium bricks are commonly used. Magnesia bricks containing more than 80% to 85% of magnesium oxide have good resistance to alkaline slag and iron slag, and the refractoriness is higher than clay bricks and silica bricks. Mainly used in open furnace, oxygen blowing converter, electric furnace, non-ferrous metal smelting equipment and some high temperature equipment.