The carbon content in traditional magnesia carbon bricks is relatively high, generally in the range of 10-20%. Due to the presence of carbon in magnesia-carbon bricks, the performance of magnesia-carbon bricks is greatly improved, making them have certain properties such as magnesia-chrome bricks and magnesia dolomite bricks. However, due to the progress of metallurgical technology and the demanding requirements for refractory materials, This has caused a series of problems in the use of traditional magnesia-carbon bricks: the excellent thermal conductivity of graphite increases the heat loss in the steelmaking process and wastes energy; the excessive graphite content will be in the process of refining outside the furnace. This increases the carbon content in molten steel, which affects the quality of molten steel, and is not conducive to the reduction of carbon content in steel; in addition, graphite is a precious resource, and traditional magnesia carbon bricks rely excessively on graphite, which is beneficial to the sustainable use of resources unfavorable. Aluminum Magnesium Carbon Brick
Converter magnesia carbon brick
However, simply reducing the graphite content in the magnesia-carbon brick will not only reduce the thermal conductivity of the magnesia-carbon brick, but also increase the thermal conductivity of the magnesia-carbon brick when it is mixed with the binder carbon raw material magnesia crushing smashing sieve distribution material. Modulus of elasticity, which will reduce the thermal shock stability of the material; in addition, due to the low wettability of graphite with molten steel and molten slag, if the graphite content in the magnesia carbon brick is reduced, the magnesia carbon brick will be easier to be The corrosion of molten steel and molten slag leads to a decrease in the corrosion resistance of the material. Therefore, research on magnesia-carbon bricks with low graphite content and excellent thermal shock stability and slag erosion resistance has become the focus of current research, and it is also a new direction for the future development of magnesia-carbon bricks.
In order to solve these contradictions and the performance of low-carbon magnesia-carbon bricks, researchers at home and abroad mainly started from improving the carbon structure of the bonded carbon, optimizing the matrix, and using antioxidants, and carried out the following work:
(1) Modified magnesia particles
In order to solve the poor thermal exfoliation of low-carbon magnesia-carbon bricks, MasayoshiKakihara et al. prepared a thin asphalt coating on the surface of the magnesia particles to reduce the thermal expansion of the magnesia particles during use, so as to improve the low-carbon magnesium Thermal shock stability of carbon bricks.
(2) Change the type of carbon source and the particle size of graphite
In order to improve the thermal and mechanical properties of low-carbon magnesia-carbon bricks, Hiroki Yasumitsu et al. studied its effect on magnesia-carbon bricks by adding nano-carbon black to the matrix of magnesia-carbon bricks. The results show that by adding a small amount of carbon black (a mixture of single spherical carbon black and polymeric carbon black), magnesia carbon bricks show outstanding excellent properties, such as reduction of elastic modulus, relaxation of thermal stress between different particles, etc. Improve the thermal shock stability and corrosion resistance of low-carbon magnesia-carbon bricks.
MousomBag1 et al. studied the effect of adding nano-sized carbon on magnesia carbon bricks. The results show that the addition of a small amount of nano-sized carbon makes the new type of magnesia carbon brick with a carbon content of about half of the ordinary magnesia carbon brick still have excellent performance. Adding different amounts of nano-sized carbon has different effects on performance, and it is found that adding 0.9 wt% of nano-sized carbon and 3 wt% of graphite as a mixed carbon source makes the material have better properties. Adding nano-carbon grades can better distribute in the matrix, fill the pores, increase the volume density, increase the strength of the magnesia-carbon brick, and enhance the corrosion resistance. In addition, nano-sized carbon can absorb and relieve thermal stress caused by thermal expansion and shrinkage of refractory particles, reduce thermal stress between different parts of the material, and improve the thermal shock stability of the material.
