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Magnesia carbon bricks have the characteristics of high fire resistance, high corrosion resistance, excellent heat spalling resistance and high temperature volume stability, as well as high thermal shock resistance. These characteristics make magnesia carbon bricks perform well in high temperature environments and are widely used in metallurgical equipment such as electric furnaces and converters. The main raw materials of magnesia carbon bricks include fused magnesia or high-purity sintered magnesia and high-purity graphite. It is usually required that the MgO content in magnesia is greater than or equal to 95%, and the carbon content in graphite is greater than or equal to 94%.
During the smelting process, the use conditions and damage of magnesia carbon bricks in different parts are different. For example, the temperature of the furnace mouth and furnace cap changes dramatically and is severely corroded by slag, so magnesia carbon bricks with good thermal shock resistance and strong slag resistance should be selected; the two sides of the ear shaft are greatly damaged during blowing, so high-quality magnesia carbon bricks with good slag resistance and good oxidation resistance should be built; the slag line is in contact with molten slag for a long time and is severely corroded by slag, so magnesia carbon bricks with excellent slag resistance should be selected.
In order to improve the oxidation resistance of magnesia carbon bricks, a small amount of additives can be added, which can generate protective substances by reacting with oxygen, or change the microstructure of carbon composite refractory materials, thereby improving their oxidation resistance.
Electric furnace magnesia carbon bricks refer to refractory products for electric furnaces made of magnesia and graphite as raw materials. Magnesia-carbon bricks have been used in electric furnace walls for about 10 years since their industrial production in 1970. Because this kind of brick has high fire resistance, high corrosion resistance, excellent heat spalling resistance, high temperature volume stability, high thermal shock resistance and other characteristics, it has been promoted and applied quickly.
The most significant difference between magnesia-carbon bricks for electric furnaces and magnesia-carbon bricks for converters is the different range of fixed carbon content. The former is 10%-30%, and the latter is 10%-20%. Therefore, more scaly graphite should be added in the production of electric furnace magnesia carbon bricks. Other production process links are the same as converter magnesia carbon bricks.
Used as lining bricks for electric furnace walls, especially for high-power and ultra-high-power water-cooled electric furnace walls, hot spots and slag lines, and other areas where the furnace walls are severely corroded. Magnesium carbon bricks are used for ultra-high power and large water-cooled electric furnace walls. The service life can reach more than 300 times. Magnesium carbon bricks are also beginning to be used for the bottom of electric furnaces.
Converter magnesia carbon bricks refer to magnesia carbon refractory products used as converter linings made of magnesia sand and graphite as the main raw materials. The main raw materials are fused magnesia sand or high-purity sintered magnesia sand and high-purity graphite. Generally, the MgO content in magnesia sand is greater than or equal to 95%, and the C content in graphite is greater than or equal to 94%. Phenolic resin or asphalt is used as a binder, and appropriate additives are selected according to the conditions of use. After batching, mixing, molding, and heat treatment, the finished product is made. Converter magnesia carbon bricks have the characteristics of high temperature resistance, strong slag resistance, good thermal shock resistance, and high high temperature strength. However, its disadvantage is that it is easy to oxidize during use, which can be improved by adding antioxidants.
During the smelting process, the use conditions and damage conditions of various parts of the converter are different. In order to achieve balanced erosion, the grades and qualities of magnesia carbon bricks selected for different parts of the converter under different use conditions are also different.
The temperature of the furnace mouth and furnace cap changes dramatically, and the slag erosion is serious. Magnesium carbon bricks with good thermal shock resistance and strong slag resistance should be selected. In addition to the damage caused by blowing, there is no protective slag layer cover on the surface of the two sides of the ear shaft, which is not easy to repair and the carbon in the brick is easily oxidized. High-quality magnesium carbon bricks with excellent slag resistance and good oxidation resistance should be built. The slag line is in contact with the slag for a long time and is seriously corroded by slag. Magnesium carbon bricks with excellent slag resistance need to be built. When oxygen is blown on the charging side, the splashing of slag and molten steel can easily cause chemical erosion, wear, scouring, and direct impact and erosion of scrap steel and molten iron. Magnesium carbon bricks with strong slag resistance, high temperature strength and good thermal shock resistance should be selected. Compared with other parts, the furnace hearth and furnace bottom are less corroded, and ordinary magnesium carbon bricks can be used. When the top and bottom composite blowing technology is adopted, especially when CO2, O2 and other gases are blown at the bottom, the damage is more serious. High-grade magnesia carbon bricks with good oxidation resistance, good thermal shock resistance, high high temperature strength and strong slag resistance should be selected. According to the different parts of the converter, selecting magnesia carbon bricks with corresponding performance is an effective way to improve the technical and economic indicators of the converter.
Anshan Justhigh New Material Development Co.,LTD can provide customers with refractory solutions design, refractory product research and development, product material production, finished product delivery, and assist on-site installation according to the operating conditions of different furnace types of customers. If you have any refractory solution problems, please contact us. We are not only a refractory material manufacturer and supplier, but also your professional refractory solution expert.
