The raw materials of andalusite bricks are high alumina bauxite, silica, andalusite, mullite, binders, additives and so on. Andalusite, sillimanite and kyanite are kyanite family minerals with the same molecular formula: Al2O3·SiO2, but their crystalline structure is different. Andalusite, sillimanite and kyanite have high refractoriness(1830℃), their chemical corrosion resistance is strong. Therefore, andalusite bricks have high mechanical strength, good abrasion resistance, high refractoriness under load, strong creep resistance and good thermal shock resistance. The main applications of andalusite bricks are glass furnace melting tank bottom back walls, key parts of blast furnace, hot blast furnace, metal mixing furnace and so on.
|Magnesia micro powder||1~3%|
|Alumina micro powder||2~8%|
Batch materials of andalusite bricks should be prepared as per formula, then after mixing and tempering, green bricks are made by mold pressing method. Then through drying and high temperature sintering, andalusite bricks are finally produced.
|Al2O3 % ≥||60||56||52|
|Fe2O3 % ≤||1.0||1.2||1.3|
|Apparent porosity % ≤||18||18||20|
|Bulk density g/cm3||≥2.45||≥2.45||≥2.45|
|Refractoriness under load (0.2Mpa) ℃ ≥||1680||1650||1600|
|Reheating linear change rate(1500℃, 3h)||+0.2~-0.1||+0.2~-0.1||+0.2~-0.1|
|Crushing strength Mpa ≥||50||45||40|
|Creep rate % ≤||0.8||0.8||0.8|
|Thermal shock stability (1100℃,water cooling) /times||≥20||≥20||≥20|
Andalusite bricks are premium refractory bricks with very good high temperature performance, such as wearing resistance, thermal shock resistance, excellent volume stability and strong corrosion resistance. In glass furnaces, andalusite bricks are a good replacement of sillimanite bricks. The main applications of andalusite bricks in float glass furnaces are tin bath roof cover, domestic and special glass kiln forehearth, feeder, tube drawing machine and other equipment. Andalusite bricks are also widely used in blast furnaces and hot blast furnaces, torpedo tank and so on.