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        What are the five most common classifications of refractories?
        Source: | Author:. | Published time: 1045 days ago | 527 Views | Share:
        At present, the most common classification of refractory materials is chemical composition classification, which can be divided into silica, aluminosilicate, magnesium, dolomite and carbon composite.
        At present, the most common classification of refractory materials is chemical composition classification, which can be divided into silica, aluminosilicate, magnesium, dolomite and carbon composite.
        1. Silica refractories
        Silica refractories are mainly composed of SiO2, which have a mass fraction of no less than 93%, which can be fixed or amorphous. The refractory has the advantages of high thermal conductivity, high softening point of load and strong resistance to acid slag erosion, but the biggest disadvantage is low thermal shock resistance stability. Therefore, the refractory is mainly used as the structural materials for coke oven, glass furnace, acid steel making furnace and other thermal equipment.
        2. Aluminosilicate refractory
        Aluminosilicate refractories are refractories with Al2O3 and SiO2 as the main components. According to the content of Al2O3 in refractories, it can be divided into semi siliceous (15% ~ 30%), clay (30% ~ 48%) and high alumina (mass fraction >48%). The refractories have the advantages of light weight, thermal stability and good insulation performance, but the initial deformation temperature is 1400 ℃. Therefore, aluminosilicate refractories are generally used as thermal insulation materials in metallurgical industry, and not for working layers.
        3. Magnesia refractory
        Magnesia refractories are mainly composed of magnesite and the MgO content is more than 80%. Influenced by the raw material composition of magnesium, the main components of magnesia refractories are MgO, FeO, Fe2O3, Al2O3, SiO2, Cao and Cr2O3. The melting point of MgO is 2800 ℃, and the refractories have a high temperature resistance of 2000 ℃. Magnesia refractories include magnesia brick, magnesium olivine refractory, magnesia aluminum spinel refractory, magnesium chromium refractory and white jade refractory. Among them, magnesia chrome refractory is made of magnesia and chromite, and magnesium sand is the main component. Compared with traditional magnesia brick, the magnesia chrome refractory has stronger thermal stability and is widely used in non-ferrous smelting furnace. However, hexavalent chromium has serious harm to environment and human health, especially to water pollution. Therefore, in the process of production and production, alkaline medium and oxygen partial pressure should be strictly controlled.
        4. Dolomite refractory
        Dolomite refractories are basic refractories with dolomite as main raw materials and MgO and Cao as main components, among which the mass fraction of Cao is 40% ~ 60%, and the mass fraction of magnesium oxide is 30% - 40%. The refractory temperature of dolomite refractories is above 1780 ℃, and the starting temperature of 0.2MPa load softening is 1550 ℃, which shows that it has good high temperature stability. Dolomite refractory belongs to strong alkaline refractory, which has strong slag resistance to alkaline slag, but it is poor for acid slag. Therefore, the refractory is mainly used for the wall and bottom of the furnace and the firing zone of the rotary kiln.
        5. Carbon composite refractory
        Carbon composite refractories, also known as carbon containing refractories, are a kind of polyphase composite refractories made from two or more different refractory oxides (MgO, Cao, Al2O3, ZrO2, etc.) and carbon and non oxide materials. The carbon composite refractories have high fire resistance, good thermal conductivity and conductivity, excellent load deformation temperature and high temperature strength, slag resistance and thermal shock resistance are better than other refractories, but these products have the disadvantages of oxidation. Therefore, the refractory is mainly used in the field of smelting stainless steel, pure steel and low sulfur steel.

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