Structure of refractory materials

- Jul 24, 2018 -

Acid refractory to silicon oxide as the main ingredient, commonly used in silica bricks and clay bricks. Silica brick is silicon products containing more than 94% silicon oxide, the use of raw materials such as silica, waste silica bricks, and its resistance to acid slag erosion capacity, high load softening temperature, repeated calcination after the volume does not shrink, or even slightly expanded, but it is susceptible to alkaline slag erosion, thermal shock resistance is poor. Silica brick is mainly used in coke oven, glass melting kiln, acid steelmaking furnace and other thermal equipment.

Clay bricks with refractory clay as the main raw material, containing 30%~46% alumina, is a weak acidic refractory, good thermal vibration resistance, corrosion resistance to acid slag, widely used. The neutral refractory is mainly composed of alumina, chromium oxide or carbon. Corundum products containing more than 95% alumina are a kind of high quality refractory with wide use. Chrome bricks with chromium oxide as the main component have good corrosion resistance to steel slag, but the thermal shock resistance is poor, and the temperature of load deformation at high temperature is low. Carbon refractories have carbon bricks, graphite products and SIC products, its thermal expansion coefficient is very low, high thermal conductivity, good heat resistance, high temperature strength, acid and alkali and salt erosion, especially weak acid alkali has a good resistance, not by metal and slag wetting, light.

Widely used as high-temperature lining material, also used as oil, chemical high-pressure kettle lining. Alkali refractory to magnesium oxide, calcium oxide as the main ingredient, commonly used is magnesium bricks. Magnesia brick with MgO 80%~85% and above has good resistance to alkaline slag and iron slag, and the fire resistance is higher than clay bricks and silica bricks.

Mainly used in open hearth, oxygen blowing converter, electric furnace, non-ferrous metal smelting equipment and some high-temperature equipment.

Refractory materials used in special occasions are high-temperature oxides, such as alumina, lanthanum oxide, beryllium oxide, calcium oxide, zirconia, refractory compounds, such as carbide, nitride, Boride, silicide and sulfide, high-temperature composite materials, mainly metal ceramics, high-temperature inorganic coatings and fiber-reinforced ceramics.

Frequently used refractories have AZS bricks, corundum bricks, direct combination of magnesia-chrome bricks, silicon carbide bricks, silicon nitride bonded silicon carbide bricks, nitride, silicide, sulfide, boride, carbide and other non-oxide refractories, calcium oxide, chromium oxide, alumina, magnesium oxide, beryllium oxide and other refractory materials.

Frequently used insulation refractories have diatomite products, asbestos products, insulation boards and so on.

Frequently used amorphous refractories have to fill the burden, ramming material, castable, plastic, refractory mud, fire-resistant shotcrete, refractory materials, refractory coatings, lightweight refractory castable, cannon mud and so on. Bulk refractory (amorphous refractories): Amorphous refractory is a refractory that is directly used without moulding and sintering, which is composed of a reasonable gradation of granular and powdered material and a binder. Usually, the granular material that constitutes this material is called aggregate, the powdered material is called admixture, and the binder is called the binding agent. This type of material without a fixed shape, can be made into slurry, paste and loose shape, and therefore also known as loose refractory.

This kind of refractory can form the whole structure without seams, so it is also called as the whole refractory. The basic composition of amorphous refractories is granular and powdery refractory materials. According to its use requirements, can be made from a variety of materials. In order to combine these refractory materials into a whole, in addition to a very few special cases, the appropriate variety and the number of binding agents are generally added. To improve its plasticity or reduce water consumption, can add a small number of appropriate plasticizer, in order to meet other special requirements, but also to add a small number of appropriate other admixtures.