Discussion on the production principle of magnesia chrome brick

Magnesia chrome brick is made of some preliminary synthesis high purity raw materials. The high purity raw refractories should be high pressure formed, ultra high temperature fired and then go through some other post-treatment process and system, finally made the magnesite chrome brick.

AOD furnace lining generally uses directly bonded MgO-Cr2O3 brick, combined with semi-re-bonded MgO-based Cr2O3 brick masonry. Directly combined with magnesia chrome refractory brick with high-quality high-purity magnesite and chrome ore at high temperature calcination, the microstructure is characterized by the formation of direct coupling between the main crystal phase, and low melting point silicate phase exists.

Combined with magnesia chrome fire bricks is fused magnesia chrome sand broken, and then fired at high temperatures, which is characterized by excellent slag resistance, the use of the effect than the direct combination of magnesia chrome brick. Semi-re-combined magnesia chrome brick is a direct combination of MgO Cr brick and re-combination of magnesia chrome brick integrated, better performance.

The Furnace with magnesia chrome brick damage causes, mainly to consider the slag infiltration and make brick body deterioration caused by structural flaking In order to improve its performance, the production of  magnesium chrome brick should be considered from the following aspects:

(1) strict control of chemical composition. Cr2O3 content (in mass fraction, the same below) to 18% is better, SiO2 content against erosion of the greatest impact, its content should be as low as possible, <1% is appropriate, and should strictly control the content of calcium oxide.

(2) brick-making process to strictly control the gradation.

Yingkou Ruizhi Refractories Co., Ltd. is a professional China manufacturer of refractory material for high temperature melting furnaces.Ruizhi Refractories supply main products are: Refractory material, refractory brick suppliers , refractory castable,refractory nozzle, ceramic fiber, fire brick, insulation material, for converter, electric arc furnace, ladle, LF furnace, tundish, foundry ladle, torpedo ladle, etc. Ruizhi has established technical cooperation relationship with some refractories china research institutions and universities. Ruizhi Refractories products have been exported to such as South Africa, Australia, Canada, Malaysia, Bangladesh, Iran, Saudi Arabia, UAE, Iraq, Pakistan, Philippines, Vietnam, Singapore, Tajikistan, Indonesia, South Korea, Sri Lanka, Nigeria, Kenya, Ethiopia, etc.

Magnesia chrome brick five performance

Magnesia chrome brick is made of some preliminary synthesis high purity raw materials. The high purity raw refractories should be high pressure formed, ultra high temperature fired and then go through some other post-treatment process and system, finally made the magnesite chrome brick.

Magnesia chrome brick five performance:
1 chemical composition and mineral composition 
Magnesia chrome brick chemical composition with the choice of raw materials vary. General magnesium oxide total of 55% to 60%, chromium oxide is about 10%, followed by ferric oxide and a small amount of aluminum dioxide, silica, calcium oxide and other impurities.
Magnesia chrome refractory bricks mineral composition is mainly magnesium chrome spinel and magnesium ferrite.
2 refractoriness
As the magnesia chrome fire bricks magnesium content less than magnesium bricks, magnesium chrome spinel and magnesium ferrite content, and their eutectic compound melting point is relatively low, so the magnesia chrome brick china refractory  magnesia, generally only 1850 ~ 1960 ℃.
3 load softening temperature
Magnesite in the magnesia-chrome brick and magnesium-chromium spinel is easy to form a mesh skeleton, because the low melting point filled in the network gap is less material, when the high temperature load, although the low melting point softening, Skeleton can still support the load, so the magnesia chrome bricks softening temperature is higher, generally up to 1550 ℃ or more. The refractoriness is slightly lower than that of the magnets and the softening temperature is higher than that of the magnets.
4 Thermal expansion and thermal shock stability
Magnesium chrome tungsten chrome spinel and magnesium ferrite content and linear expansion coefficient is small, at the same time, magnesium chrome brick porosity than magnesium bricks, so the MgO Cr brick thermal expansion is small.
Magnesia-chrome brick calcium perovskite content is very small, not easy to cause the expansion of the expansion of stress; magnesium ferrite dissolved in the magnesium chrome spinel, the solubility of large two dissolved temperature range is also wide, the melting and precipitation of magnesium ferrite , And will not produce large stress, therefore, magnesia chrome brick thermal shock stability is better, the number of water up to 25 times.
5 slag resistance
Magnesia chrome brick in the content of more magnesium chrome spinel is magnesium oxide and chromium oxide complex, and chromium trioxide is a typical neutral oxide, therefore, magnesium chrome brick on the alkaline, acidic slag erosion Have a strong resistance.
Yingkou Ruizhi Refractories Co., Ltd. is a professional China manufacturer of refractory material for high temperature melting furnaces.Ruizhi Refractories supply main products are: china refractory materials, refractory brick, refractory castable,refractory nozzle, ceramic fiber, fire brick, insulation material, for converter, electric arc furnace, ladle, LF furnace, tundish, foundry ladle, torpedo ladle, etc. Ruizhi has established technical cooperation relationship with some refractory research institutions and universities. Ruizhi Refractories products have been exported to such as South Africa, Australia, Canada, Malaysia, Bangladesh, Iran, Saudi Arabia, UAE, Iraq, Pakistan, Philippines, Vietnam, Singapore, Tajikistan, Indonesia, South Korea, Sri Lanka, Nigeria, Kenya, Ethiopia, etc.

Advantages and application scope of refractory fiber castable

Refractory fiber castable by the construction method can be divided into different coating materials, casting materials, spray paint. Its main performance is a low thermal conductivity, strong thermal stability, a certain pressure strength, a certain anti-air erosion ability, a certain resistance to mechanical vibration, integrity, construction is simple and rapid clean, Maintenance and repair is simple, oven time is short and simple to use long life.

Application scope of refractory fiber castable:
1. When the working temperature ≤ 1250 ℃ of the various fuel furnace lining, including the furnace wall and roof. Choose different types of refractory material fiber castable made of composite lining, stable structure, economical and reasonable, easy construction.
2. High temperature furnace temperature ≤ 1050 ℃ interface insulation layer (including the furnace wall and roof).
3. Industrial boiler lining, for the roof effect is more significant.
4. The working temperature ≤ 1200 ℃ resistance furnace lining, electric components can be exposed, can also be made into a buried structure.
5. The use of flat flame burner industrial furnace, the top seal insulation, sealing effect is better than any other material.
6. Flue, large diameter metal chimney insulation under the insulation.
7. High temperature air (≤ 1200 ℃) pipe insulation.
8. A variety of thermal equipment lining layer.
9. The work of mechanical vibration, the temperature changes in the range of large lining is particularly applicable, such as hood-type furnace, can be exposing aluminum melting furnace furnace cover and so on.
10. All kinds of ordinary and special-shaped prefabricated parts, to meet the special needs of users.
11. Carburizing fiber castable for no muffle carburizing furnace lining.


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