Raw materials for manufacturing magnesia carbon bricks

Magnesia carbon brick is made of magnesia, calcined magnesia, fused magnesia, high-purity magnesia, high-quality graphite and bauxite additives. The price and performance of magnesia carbon brick are closely related to the graphite content in the brick. With the increase of graphite content, the strength of brick decreases, the thermal expansion rate decreases and the residual expansion rate increases. Magnesia brick manufacturer

Therefore, the manufacturer of magnesia carbon brick should control the graphite content in the brick at about 20%. Magnesia carbon brick has small wettability to molten slag and has excellent peeling resistance and corrosion resistance. It is suitable for the slag line of ladle, especially for the occasion of multi furnace continuous casting. In order to meet the needs of producing clean steel, the application position of magnesia carbon brick has expanded from the slag line to the side wall during refining in ladle.

When laying magnesia carbon bricks on the ladle, pay attention not to mix with bricks with high SiO2 content. Otherwise, the local melting loss of MgO-C brick will be increased, and the melting loss mechanism is;

It is mainly used for the lining and tapping port of steelmaking oxidation conversion furnace, the hot spot of high-power electric furnace wall, the lining of refining furnace outside the furnace, the slag line of steel barrel, etc. Ladle magnesia carbon brick

The raw materials for manufacturing magnesia carbon brick are high-quality sintered magnesia, fused magnesia, graphite, binder and antioxidant. Periclase particles in magnesia play the role of aggregate in refractory bricks. In order to produce high-quality magnesia carbon brick, high-purity magnesia (MgO content as high as possible, / SiO2 ≥ 2, bulk density ≥ 3.34g/cm3, good crystal development, porosity of magnesia itself ≤ 3%) shall be selected. Graphite is also the main raw material of magnesia carbon brick. Its fixed carbon content, ash composition, oxidation resistance, particle size, shape, volatile matter and moisture directly affect the performance and application effect of magnesia carbon brick. High purity flake or flake graphite with high carbon content (C ≥ 95-96%) is selected to make bricks, so as to improve the corrosion resistance, spalling resistance, high temperature strength and oxidation resistance of magnesia carbon bricks.

The binder used in magnesia carbon brick is very important, and its quality will affect the production and quality of refractory brick to a great extent. There are many kinds of materials that can be used as magnesia carbon brick binder, such as coal tar, coal asphalt and petroleum asphalt, special carbon resin, polyol, asphalt modified phenolic resin, synthetic resin, etc. Because the phenolic resin is thick A has high carbon residue rate, good affinity with magnesia and graphite, easy to combine magnesia and graphite, and easy to spread in magnesia and graphite at room temperature. Therefore, phenolic resin is still a good binder for the production of magnesia carbon brick. Due to the use of high-purity graphite in magnesia carbon brick, the amount of liquid phase generated in the brick is small, and oxygen is easy to penetrate into the brick to oxidize and decarbonize the graphite, and the oxidation resistance of the brick becomes worse. Therefore, antioxidants such as metal A1, Si, A1 Si, Al Mg alloy and SiC must be added. They can preferentially react with oxygen to form carbonization or oxide, and expand the volume, block or fill pores to densify the brick, so as to improve the oxygen resistance ratio of refractory brick.