Refractory materials are a class of inorganic non-metallic materials with refractoriness not lower than 1580℃.

Refractoriness refers to the temperature in degrees Celsius at which the refractory cone sample resists high temperature without softening and melting under the condition of no load. However, the definition of refractoriness alone cannot fully describe the refractory material, and 1580 ℃ is not absolute.

Now defined as any material whose physical and chemical properties allow it to be used in a high temperature environment, it is called a refractory material. Refractory materials are widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, power and other industrial fields. They are the largest in the metallurgical industry, accounting for 50% to 60% of the total output.

At present, the most common classification method of refractory materials is chemical composition classification, which can be divided into refractory materials such as silica, aluminosilicate, magnesia, dolomite and carbon composite.

1. Silica refractory

Silica refractory material is a refractory material with SiO2 as the main component and the mass fraction of SiO2 is not less than 93%, which can be shaped or unshaped refractory. The refractory material has the advantages of thermal conductivity, high softening point under load, and strong resistance to acid slag erosion, but the biggest disadvantage is the low thermal shock resistance stability. Therefore, the refractory material is mainly used as a structural material for coke ovens, glass melting furnaces, acid steelmaking furnaces and other thermal equipment.

2. Aluminosilicate refractories

Aluminosilicate refractories are refractories with Al2O3 and SiO2 as the main components. According to the content of Al2O3 in the refractory, it can be divided into semi-siliceous (mass fraction 15% to 30%), clay (30% to 48% mass fraction) and high alumina (mass fraction> 48%) refractory. The refractory material has the advantages of light weight, thermal stability and good thermal insulation performance, but its initial deformation temperature is 1400 °C. Therefore, aluminosilicate refractories are generally used as insulation materials in the metallurgical industry, not for working layers.

3. Magnesium refractory

The magnesia refractory is a refractory with periclase as the main crystal phase and the mass fraction of MgO greater than 80%. Influenced by the composition of magnesia raw materials, the main components of magnesia refractories are MgO, FeO, Fe2O3, Al2O3, SiO2, CaO, Cr2O3. The melting point of MgO is as high as 2800°C, and the refractoriness of magnesia refractories reaches 2000°C, so magnesia refractories have good high temperature resistance. The magnesia refractories include magnesia bricks, forsterite refractories, magnesia-aluminum spinel refractories, magnesia chrome refractories, and white jade refractories. Among them, magnesia-chromium refractories are made of magnesia and chromite, and magnesia is the main component. Compared with traditional magnesia bricks, magnesia-chromium refractories have stronger thermal stability and are widely used in non-ferrous smelting furnaces. However, because hexavalent chromium has serious harm to the environment and human health, especially to water, it is necessary to strictly control the alkaline medium and oxygen partial pressure in the production and production process.

4. Dolomite refractory

Dolomite refractories are basic refractories with dolomite as the main raw material and MgO and CaO as the main components, in which the mass fraction of CaO is 40% to 60%, and the mass fraction of magnesium oxide is 30% to 40%. The refractory temperature of the dolomite refractory is above 1780°C, and the softening start temperature under 0.2MPa load is 1550°C. It can be seen that it has good high temperature stability. Dolomite refractory material belongs to strong alkaline refractory material, which has strong slag resistance to alkaline slag, but poor slag resistance to acidic slag. Therefore, the refractory material is mainly used for the wall and bottom of the open hearth furnace, the firing zone of the rotary kiln, and the like.

5. Carbon composite refractories

Carbon composite refractories, also known as carbon-containing refractories, are made of two or more refractory oxides (MgO, CaO, Al2O3, ZrO2, etc.) with different properties and carbon materials and non-oxide materials. A multiphase composite refractory material made of plain material as a binder. Carbon composite refractories have high refractoriness, good thermal conductivity and electrical conductivity, excellent load deformation temperature and high temperature strength, and better slag resistance and thermal shock resistance than other refractory materials, but this type of products are prone to oxidation. shortcoming. Therefore, the refractory material is mainly used in the smelting of high-quality steel such as stainless steel, pure steel and low-sulfur steel.

In addition to the above classification methods, refractory materials can also be classified by other methods. For example, it can be divided into blast furnace bricks, coke oven bricks and ingot bricks according to the application; according to the production process and construction characteristics during use, it can be divided into shaped products and unshaped refractory materials.

Among all the classification methods of refractory materials, the classification method based on chemical-mineral composition is more important, because this classification method reflects the nature and characteristics of various refractory materials.

Refractory materials are used in various fields of the national economy such as iron and steel, non-ferrous metals, glass, cement, ceramics, petrochemicals, machinery, boilers, light industry, electric power, and military industry, and are essential basic materials to ensure the production operation and technological development of the above-mentioned industries. It plays an irreplaceable and important role in the development of high temperature industrial production.

Anyang Fuyaochang Metallurgical Refractory Material Co., Ltd. has many years of experience in the market of refractory materials. The company's products include copper, iron, gold, silicon carbide, silicon calcium alloy, silicon aluminum iron, silicon aluminum lead calcium and silicon required by casting, materials and other industries.
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