The raw materials for making magnesia carbon bricks are high-quality sintered magnesia, fused magnesia, graphite, binders antioxidants.
The periclase particles in magnesia act as aggregates in refractory bricks. To manufacture high-quality magnesia-carbon bricks, high-purity magnesia should be selected for magnesia-calcium synthetic sand (MgO content is as high as possible, /SiO2≥2, bulk density ≥3.34g/cm3, crystal development is good, magnesia itself has a porosity of ≤3% ).
Graphite is also the main raw material of magnesia carbon bricks. Its fixed carbon content, ash composition, oxidation resistance, particle size, shape, volatile content, moisture all directly affect the performance use effect of magnesia carbon bricks. high-purity flake flake graphite with high carbon content (C≥95-96%) to make bricks to obtain the corrosion resistance, spalling resistance, high temperature strength, oxidation resistance other characteristics of magnesia carbon bricks.
The binder used in magnesia-carbon bricks is very important, its quality greatly affects the production quality of refractory bricks.
There are many types of materials that can be used as binders for magnesia-carbon bricks, such as coal tar, coal tar petroleum pitch, carbon resins, polyols, pitch-denatured phenolic resins, synthetic resins. Due to the high carbon residue rate of phenolic thick. A purpose, it has good affinity with magnesia graphite. It is easy to combine magnesia graphite. It is easy to spread in magnesia graphite at room temperature. Resin is still a better binder for the production of magnesia carbon bricks.
Since magnesia carbon bricks use high-purity graphite, the amount of liquid phase generated in the bricks is small, oxygen can easily penetrate into the bricks to oxidize decarburize the graphite, the oxidation resistance of the bricks will deteriorate. For this reason, metals A1, Si, A1-Si, Al-Mg alloy, SiC other antioxidants. They can preferentially react with oxygen to form carbon compounds oxides, expand in volume, block fill pores to densify the bricks, thereby improving the anti-oxygen performance of the refractory bricks.