The price of magnesia carbon bricks for the general properties of refractory materials

The commonly used varieties of ordinary and special refractory materials include the following: magnesium bricks for glass kilns

The larger quantities include silica bricks and clay bricks. Silicon bricks are siliceous products containing over 93% SiO2, using raw materials such as silica and waste silicon bricks. Silicon bricks have strong resistance to acid and slag erosion, but are susceptible to alkaline slag erosion. Their load softening temperature is very high, close to their fire resistance. After repeated calcination, their volume does not shrink, and even slightly expands, but they are resistant to

Poor thermal shock resistance. Silicon bricks are mainly used in thermal equipment such as coke ovens, glass furnaces, and acid steelmaking furnaces. Clay bricks contain 30% to 46% alumina. They are mainly made of refractory clay, with a fire resistance of 1580 to 1770 ℃ and good thermal shock resistance. They belong to the category of weakly acidic refractory materials and have corrosion resistance to acidic slag. They are widely used and are a type of refractory material in production.

The main crystalline phases in high alumina products are mullite and corundum, and the content of corundum increases with the increase of alumina content. Corundum products containing over 95% alumina are a high-quality refractory material with a wide range of uses. The chrome brick is mainly made of chrome ore, and the main crystal phase is Chromite. It has good corrosion resistance to steel slag, but poor thermal shock resistance, and lower high-temperature load deformation temperature. Chromium magnesium bricks made of chromium ore and magnesia in different proportions have good thermal shock resistance and are mainly used as alkaline top bricks for open hearth furnaces.

Carbon based products are another type of neutral refractory material, which can be divided into three categories based on the composition of carbon containing raw materials and the mineral composition of products: carbon bricks, graphite products, and silicon carbide products. Carbon brick is made from high-grade Petroleum coke as raw material, adding tar and asphalt as binder, and fired at 1300 ℃ under air isolation condition. Graphite products (excluding natural graphite) are made from carbon materials by graphitization treatment at 2500-2800 ℃ in an electric furnace. Silicon carbide products are made from silicon carbide as raw material and fired at 1350-1400 ℃ with binders such as clay and silicon oxide. Silicon nitride silicon carbide products can also be made by adding silicon carbide powder in a nitrogen atmosphere in an electric furnace.

Carbon products have a low coefficient of thermal expansion, high thermal conductivity, good thermal shock resistance, and high high-temperature strength. Long term use at high temperatures does not soften, is not subject to any acid or alkali corrosion, has good salt resistance, and is not wetted by metals and slag. It is lightweight and is a high-quality high-temperature resistant material. The disadvantage is that it is prone to oxidation at high temperatures and should not be used in an oxidizing atmosphere. Carbon products are widely used in high-temperature furnace lining (furnace bottom, hearth, lower part of furnace body, etc.) and lining of non-ferrous metal smelting furnaces. Graphite products can be used as the lining of reaction tank and petrochemical Autoclave. Silicon carbide and graphite products can also be made into crucibles for melting copper, gold, and light alloys.

alkalinity

Represented by magnesium products. It contains over 80% to 85% magnesium oxide, with periclase as the main crystalline phase. The main raw materials for producing magnesia bricks are Magnesite, seawater magnesia, Magnesium hydroxide extracted from seawater and calcined at high temperature. It has good resistance to alkaline slag and iron slag. The melting point of pure magnesium oxide is as high as 2800 ℃, therefore, the fire resistance of magnesium bricks is higher than that of clay bricks and silicon bricks. Since the mid-1950s, the production of alkaline refractory materials has gradually increased due to the use of oxygen blowing converter steelmaking and the use of alkaline open hearth furnace tops, while the production of clay bricks and silica bricks has decreased. Alkaline refractory materials are mainly used in open hearth furnaces, oxygen blowing converters, electric furnaces, non-ferrous metal smelting, and some high-temperature thermal equipment.