In the iron and steel metallurgy industry, refractories play a vital role. Refractory is a kind of material that can withstand high temperature, has good thermal shock resistance, corrosion resistance and mechanical strength, and its performance directly affects the efficiency, quality and cost of iron and steel metallurgy production.
1.the type and characteristics of refractory materials
1.1. Acid refractory
It is mainly represented by siliceous materials, such as silicon bricks. Silica brick has high refractoriness and load softening temperature, and has good resistance to acid slag. However, its thermal shock resistance is poor, and it is easy to break when the temperature changes rapidly. Silica brick is widely used in coke oven, hot blast stove and other high temperature equipment.
1.2. Alkaline refractory materials
Including magnesia, dolomite and other refractory materials. Magnesia brick has good fire resistance and anti-alkaline slag attack ability, but the coefficient of thermal expansion is large, and the thermal shock resistance is relatively weak. Dolomite brick has the advantages of magnesium and calcium refractory, and has certain resistance to alkaline and weakly acidic slag. Basic refractory materials are mainly used in steel furnaces, hot metal ladle and other equipment.
1.3. Neutral refractory material
It is represented by high aluminum and carbon refractories. High alumina brick has high refractoriness, mechanical strength and chemical stability, and has certain resistance to acidic and alkaline slag. Carbon refractories have good thermal conductivity, thermal shock resistance and corrosion resistance, and are widely used in the key parts of high temperature equipment such as electric furnace and converter.
2, the application of refractory materials in all aspects of iron and steel metallurgy
2.1. Ironmaking
In the process of blast furnace ironmaking, the lining needs to withstand high temperature, high pressure, scouring and chemical erosion of the charge and slag. The composite structure of carbon brick and ceramic cup is generally used in the hearth and bottom of blast furnace. The carbon brick has good thermal conductivity and corrosion resistance, while the ceramic cup can improve the thermal insulation performance and corrosion resistance of the hearth. High aluminum bricks or silicon carbide bricks are usually used in the belly, waist and lower part of the blast furnace. These refractory materials can withstand high temperature and the scouring of the charge, and have certain resistance to alkali metal and zinc vapor.
2.2. Steelmaking link
In the process of steelmaking, the use of refractory materials is more severe. The lining of the converter is mainly made of magnesia carbon brick, which has good thermal shock resistance, corrosion resistance and oxidation resistance, and can adapt to the rapid steel making rhythm of the converter. The lining of electric furnace is generally made of magnesia knotting material or magnesia carbon brick, the cost of magnesia knotting material is low, but the service life is relatively short; Magnesium-carbon bricks have better performance and longer service life. Ladle lining is usually made of high aluminum brick, magnesia carbon brick or corundum spinel brick, etc. These refractory materials can withstand high temperature and scouring of molten steel, and have certain adsorption effect on inclusions in molten steel, which is conducive to improving the quality of molten steel.
2.3. Continuous casting link
In continuous casting process, tundish is the transition container of molten steel from steelmaking furnace to casting billet, and the tundish lining is generally made of high aluminum, magnesium or magnesia calcium refractory. These refractory materials can withstand high temperature and scouring of molten steel, and have a certain filtering effect on inclusions in molten steel, which is conducive to improving the quality of casting billet. Crystallizer is the key equipment of continuous casting, crystallizer copper plate is generally made of copper alloy material, its surface needs to be sprayed with a layer of refractory materials, such as zirconium, magnesium or aluminum refractory, to improve the service life of the crystallizer and the surface quality of the casting billet.
3, the development trend of refractory materials
3.1. High performance
With the continuous progress of iron and steel metallurgy technology, the performance requirements of refractory materials are becoming higher and higher. Future refractories will pay more attention to improving performance indicators such as refractoriness, thermal shock resistance, erosion resistance and mechanical strength to meet harsh production conditions such as high temperature, high pressure and rapid steelmaking.
3.2. Functionalization
In addition to the traditional fire resistance function, future refractory materials will also have more functions, such as heat insulation, heat preservation, filtration, adsorption and so on. These functional refractory materials can improve the efficiency, quality and energy saving effect of iron and steel metallurgy production.
3.3. Green
Refractories will produce certain environmental pollution in the process of production and use. Future refractories will pay more attention to green environmental protection, using non-polluting or less polluting raw materials and production processes to reduce the impact on the environment. At the same time, the recycling of waste refractories will also become the future development trend.
In short, refractory materials have an irreplaceable role in the iron and steel metallurgy industry. With the continuous progress of iron and steel metallurgy technology, refractories will also continue to develop and innovate, providing a more reliable guarantee for the sustainable development of the iron and steel metallurgy industry.
