1. There is a difference between the two crystal phases
Andalusite mullite bricks and andalusite high alumina bricks each have their own advantages. Although the main components of mullite bricks and high alumina bricks are alumina, their crystal phases are different.
2. Description of the two crystal phases
When andalusite is heated to 1300°C, it will turn into mullite, which has the characteristics of resistance to rapid cooling, strong impact resistance, and high load conversion point. Mullite itself has low thermal expansion and thick crystals during the conversion process. Andalusite does not need to be calcined and can be directly added to fired or unfired mullite bricks and high alumina bricks. Andalusite has the advantage of creep resistance. During use, impurities can cause premature softening of refractory bricks and have a great impact on creep. Therefore, a certain proportion of andalusite is added to mullite bricks or high alumina bricks. Make it resistant to high temperatures, rapid cooling and rapid heating.
3. Performance of high alumina bricks
Andalusite high-alumina bricks are made of andalusite as the main raw material, adding bauxite, and are formed by high-pressure molding, drying, and firing at 1500°C. The characteristics of andalusite high alumina bricks are high temperature resistance, high softening temperature under load, low creep rate at high temperatures, stable volume at high temperatures without volume, small thermal expansion coefficient and low thermal conductivity during use. The refractory degree of andalusite is 1830°C, and it is resistant to chemical corrosion. Adding andalusite to high-alumina refractory bricks can make the high-alumina bricks have wear resistance, higher load softening temperature, and better resistance to rapid cooling and rapid heating. It can densify brick joints at high temperatures, improve the overall compactness of high-alumina brick masonry, and thereby improve slag permeability resistance.
4. Andalusite-mullite has the advantages of good oxidation resistance
Andalusite mullite brick is a refractory brick made of andalusite and mullite in different proportions. This brick has good oxidation resistance, strong fire resistance, high compressive strength, low specific gravity and anti-peeling properties. Good, high temperature flexural strength and long service life.
In short, andalusite mullite and andalusite high alumina bricks have similarities but also great differences. Andalusite mullite bricks are more expensive than andalusite high aluminum bricks, while andalusite high-alumina bricks have strong high temperature corrosion resistance. Andalusite-mullite bricks have good flexibility and stronger resistance to peeling.
