Magnesia carbon brick

The raw materials for the production of magnesia carbon bricks by magnesia brick manufacturers are high quality sintered magnesia, fused magnesia, graphite, binders and antioxidants.

The periclase particles in the magnesia act as aggregates in the refractory bricks. In order to produce high-quality high-strength magnesia carbon bricks, high-purity magnesia should be selected (MgO content is as high as possible, CaO/SiO2≥2, bulk density≥3.34g/cm3, crystal development is good, magnesia itself porosity ≤3%) .

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 all directly affect the performance and use effect of magnesia carbon brick. High-purity scaly or flake graphite bricks with high carbon content (C≥95-96%) are used to ensure the corrosion resistance, spalling resistance, high temperature strength and oxidation resistance of magnesia carbon bricks.

The binder used in magnesia carbon bricks is very important, and its quality largely affects the production and quality of refractory bricks.

There are many kinds of substances that can be used as magnesium-carbon brick binders, such as coal tar, coal tar and petroleum asphalt, special carbon resin, polyol, asphalt modified phenolic resin, synthetic resin and the like. Due to its high residual carbon ratio, it has good affinity with magnesia and graphite. It is easy to combine magnesia and graphite. It is easy to spread in magnesia and graphite at room temperature. So far, phenolic Resin is still a good binder for the production of magnesia carbon bricks.

Since the magnesia carbon brick uses high-purity graphite, the amount of liquid phase generated in the brick is small, and oxygen easily permeates into the brick to oxidize and decarbonize the graphite, and the oxidation resistance of the brick is deteriorated. Therefore, it is necessary to add metal A1, Si, A1-Si. , Al-Mg alloy, SiC and other antioxidants. They preferentially react with oxygen to form carbides or oxides, and undergo volume expansion, plugging or filling the pores to densify the bricks, thereby improving the antioxidant performance of the refractory bricks.