Magnesia bricks exhibit different properties in terms of erosion resistance, mainly depending on their chemical composition and microstructure. The following is a comparison of the erosion resistance of several magnesium based bricks:
1. Magnesia chrome brick
Magnesia chromium bricks are made by sintering a mixture of magnesia sand and chromite, and have high refractoriness and strong resistance to alkaline slag erosion. It has good structural stability and low porosity at high temperatures, therefore it has excellent resistance to slag erosion. However, due to the toxicity of hexavalent chromium, the number of countries producing and using magnesia chrome bricks has gradually decreased.
2. Magnesium aluminum spinel brick
Magnesium aluminum spinel bricks have good seismic and reduction resistance, but perform poorly in terms of fire resistance. This type of brick exhibits strong resistance to alkali erosion when used in an alkaline atmosphere. Its thermal conductivity is low, thermal expansion coefficient is small, strength is high, and hardness is large, so it also has good performance in corrosion resistance.
3. Magnesium calcium brick
Magnesia calcium brick is mainly made of magnesia sand and calcium sand, and has good resistance to alkaline slag erosion. Research has shown that for CaO-SiO2 slag, the slag corrosion resistance of bricks increases with the increase of CaO content in the bricks; For CaO-Al2O3 slag, the situation is the opposite. Regardless of the type of slag, the penetration depth of the slag decreases with the increase of CaO content in the brick.
4. Magnesium insulated lightweight refractory brick
Magnesium insulated lightweight refractory bricks have the characteristics of high temperature resistance, high strength, and significant energy-saving effect. It can be used for building insulation layers and areas without strong erosion and scouring effects from high-temperature molten materials. When in direct contact with flames, the surface contact temperature of high alumina insulated refractory bricks shall not exceed 1350 ℃.
Summary
In summary, different types of magnesia bricks have their own advantages and disadvantages in terms of erosion resistance. Although magnesia chrome bricks have strong corrosion resistance, their use is limited due to environmental issues. Magnesium aluminum spinel bricks and magnesium calcium bricks exhibit good corrosion resistance under specific conditions, while magnesium based lightweight refractory bricks are suitable for insulation layers in high-temperature environments. When selecting specific refractory bricks, comprehensive consideration should be given based on actual usage conditions and environmental requirements.