The research and practice indicate that the quality of raw materials has a great influence on the application effect of magnesia-carbon brick for converter. Therefore, it is necessary to choose all kinds of raw materials. Selection of magnesia

The erosion and loss process of magnesia particles in the application process of magnesia-carbon brick is roughly as follows:

(1) magnesite particles and graphite under high temperature vacuum attack solid phase reaction is as follows: MgO+C MG ↑+CO↑ generated steam and CO volatilization;

(2) Magnesite particles by slag chemical melting loss, including the melting loss of foreign slag and various oxides in magnesia impurities;

(3) The binding strength of magnesia-carbon brick substrate decreases after oxidation and decarburization. Under the penetration and scouring of slag, the calcitrite particles are washed into the slag from the brick.

Japanese scholars on MgO style of fused magnesia content and the relationship between the corrosion depth and the slag resistance of magnesia carbon brick and magnesite China magnesium stone grain size as the deepening of the research, the relationship between the result can clearly see that the consumption of magnesium carbon brick not only need to pay attention to the purity of magnesite, but also pay attention to and the use of large crystal fused magnesia, and hope that CaO/SiO2 2 or higher. After fully consider the factor, the use of magnesium carbon brick chose periclase crystal grain size is big, the binding force strong and less impurity, high content of magnesium in magnesite as main raw materials, the magnesite not only reduce the periclase crystal degree of silicate phase contact, adding slag corrosion rate of grain boundary, also can improve the magnesia and graphite of high temperature could be moved. Liaoning magnesium-carbon brick

The consumption technology of magnesia-carbon brick for converter is generally unfired product, and the consumption technology mainly includes preparation of raw material processing, batching, mixing, forming and thermal disposal. (See the process flow chart of magnesia-carbon brick below)

A. The batching process: it is an important process. 1. It should be measured strictly according to the requirements of formula size and ratio, which is the most fundamental requirement. As a batching personnel can first identify raw materials, correct and skilled use of measuring tools; Work should pay attention to observe whether the raw material color, particle size, smell, concentration, feel and other aspects of the change, such as abnormal should be immediately reflected. All the granule material, powder material can not have wet, caking phenomenon, pay attention to rain, moisture-proof. 1-0 below the fine powder to double plastic moisture-proof packaging.

B. Mixing process: it is also an important process, because the forming function of the mixed mud directly affects the quality of the brick. General requirements for feeding sequence: coarse magnesia particles, medium granules (3-6, 1-3, 1-0) -- phenolic resin -- graphite -- magnesia fine powder, additive. After the incorporation of granular materials, the incorporation of binder in low-speed mixing for a period of time makes the liquid resin adhere evenly on the particles. At the end, the incorporation of graphite makes it stick to the liquid film of magnesia particles through mixing and extrusion, and presses the graphite stuck on the shell of magnesia particles to the particles after mixing and extrusion, and squeeges out part of the excess resin. At this time to stop high-speed mixing, otherwise it will make the graphite floating on the material can not make a good mud. Because graphite has good thermal conductivity and small heat capacity, and the heat capacity of coarse magnesia particles is large, the friction heat during high-speed mixing is conducive to wetting graphite. Only when the above sequence, after the completion of talents in magnesia powder and additives such as practice, continue to mix when the graphite, magnesia particles, powder and additives have been wetting, particles and the excess bond also basically all crowd out, at the same time, the graphite of magnesia particles outside the package is relatively dense pressure onto the particles, mixed practice to end.

Electrofused magnesia: it is an alkaline refractory material formed by melting natural magnesite, light burning magnesia or sintered magnesia in an electric arc furnace. The main crystal phase of fused magnesia is magnesite, the melting point is 2800℃, the sublimation at the end of 1600℃ in vacuum, the sublimation at the end of 2000℃ or more in the recovery atmosphere, the density is greater than 3.40g/cm3, the porosity is 0%-10%, the Mohrenheit hardness is 5.5, the corrosion resistance of alkaline slag is very strong, the chemical properties are shaky, At 1500℃ high temperature and in addition to the silicon brick between a variety of refractory or weak response. The surface should be clear after complete melting crystallization, and it is not allowed to be mixed with other magnesia or sundry.

The main composition of magnesium-carbon brick: magnesium-carbon brick is a refractory product made of magnesia and graphite as the main raw materials plus excessive binder after high pressure molding and low temperature thermal treatment. Magnesia-carbon brick is a new type of refractory product that was developed in Japan in the early 1970s. It is mainly used for converter lining for steelmaking, working lining for electric furnace and working lining for ladle refining outside furnace.

What is the difference between magnesia-carbon brick and alumina-magnesia-carbon brick? The difference between magnesia-carbon brick and alumina-magnesia-carbon brick is that the materials used are different. Magnesia-carbon brick is a resin-bonded brick made of fused magnesia and graphite. Magnesium iron bricks, if required, can also be added with antioxidants. Magnesium carbon bricks perform well in heat resistance, corrosion resistance, corrosion resistance, and spalling resistance. Magnesium carbon brick is mainly used in the lining of converter, electric arc furnace, DC electric arc furnace, ladle slag line and so on. Magnesia-alumina-carbon bricks are made of high-quality bauxite, corundum, fused magnesia and graphite. Aluminum-magnesium-carbon bricks have appropriate residual expansion, low thermal conductivity and better insulation. Aluminium magnesium carbon bricks are used for slag line of ladle, lower part of ladle wall, bottom of ladle and free zone of ladle.