A large number of studies have shown that the purity of graphite in wholesale magnesium carbon bricks is directly related to the high-temperature flexural strength of magnesium carbon bricks and the melting loss rate during use.

       The high temperature flexural strength of magnesia-carbon bricks increases with the increase of graphite purity. This is a result of the difference in the microstructure of magnesia-carbon bricks. The proportion of coarse pores (diameter 20 μm) after magnification of magnesium-carbon bricks made of graphite with lower purity after carbonization at 1000 ° C is larger, and the porosity is also smaller than Products made of high purity graphite are high. This may be related to the high flexibility of high-purity graphite and the compressibility when making bricks. Another point is that the structure of magnesia-carbon bricks made of graphite with lower purity is locally weakened. After the magnesia-carbon bricks are treated at a sufficiently high temperature (such as 1600 ° C), the silicate minerals associated with graphite melt into a glass phase and interact with magnesia. Or carbon reacts, causing the original mineral to be damaged, the volume is reduced, the contact area is reduced, and stomata bands are formed around the graphite, which causes the high temperature strength of the magnesium carbon brick to decrease as the purity of the graphite decreases.

       The melting loss rate of magnesium carbon brick decreases with the increase of graphite purity, especially for graphite with a purity greater than 95%. The research on the mechanism of magnesia-carbon bricks wholesale shows that above 1300 ℃, the impurities (SiO2, CaO, Al2O3, Fe2O3, etc.) in magnesia and graphite aggregate to the junction of the two to form a low-melting substance and make magnesia particles It is susceptible to slag erosion and flows into the slag, thereby reducing erosion resistance. The actual use results show that the slag resistance of magnesium-carbon bricks made of more than 95% carbon-containing graphite is 0.51 times higher than that of ordinary magnesium-carbon bricks.

       The use of high-carbon flake graphite with a carbon content greater than 95% to 96% is an effective technical measure to improve the quality of magnesium carbon bricks and reduce the cost of making bricks. If the performance of bricks made from graphite and magnesia raw materials of the same grade is used as a benchmark, then the use of high-grade graphite will greatly improve the brick performance than increasing the grade of magnesia. Under the same process conditions, the performance of bricks made of high-grade graphite and low-grade magnesia is better than that of bricks using high-grade magnesia and low-grade graphite. However, it must be noted that when graphite with higher purity is used, less liquid phase is generated in the brick, and oxygen is easily concentrated into the brick to cause oxidative decarburization of the graphite. To this end, antioxidants such as metals Al, Si, and Al- must be added. Mg alloy, SiC, BN, etc.