Magnesium chromium brick manufacturers tell you the relationship between graphite purity and wholesale of magnesium carbon bricks

Numerous studies have shown that the purity of wholesale graphite in magnesia carbon bricks is directly related to the high-temperature flexural strength and melting loss rate of magnesia carbon bricks during use

The high-temperature flexural strength of magnesia carbon bricks increases with the increase of graphite purity. This is the result of the different microstructures of magnesia carbon bricks. Magnesia carbon bricks made of lower purity graphite have coarse pores (diameter 20) after carbonization treatment at 1000 ℃ μ m) The proportion is relatively large, and the porosity is also higher than products made of high-purity graphite. This may be related to the high flexibility of high-purity graphite and its easy compression during brick making. Another point is that the structure of magnesium carbon bricks made of lower purity graphite is locally weakened. After being treated at a sufficiently high temperature (such as 1600 ℃), the silicate minerals associated with graphite melt into a glass phase and react with magnesium sand or carbon, causing erosion of the original minerals, reduction of volume, reduction of contact area, and formation of pore zones around the graphite, resulting in a decrease in high-temperature strength of magnesium carbon bricks with a decrease in graphite purity.

The melting loss rate of magnesia carbon bricks decreases with the increase of graphite purity, especially for graphite with a purity greater than 95%. Research on the mechanism of magnesia carbon brick wholesale shows that at temperatures above 1300 ℃, impurities (SiO₂, CaO, Al₂O₃, Fe₂O₃, etc.) in magnesia and graphite aggregate towards the junction of the two, forming low melting substances, making magnesia particles easily eroded by the slag and flowing into the slag, thereby reducing their corrosion resistance. The actual use results show that the slag resistance of magnesia carbon bricks made of graphite containing over 95% carbon electricity is 0.51 times higher than that of ordinary magnesia carbon bricks.

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