refractoriness
The refractoriness of high alumina brick is better than that of clay brick and semi-silica brick, which is up to 1750~1790℃ and belongs to senior refractory material.
Refratoriness under load (T0.6,℃)
Because of high Al2O3 content in high aluminum products and less impurities and vitreous, refratoriness under load is higher than that of clay brick. However, refratoriness under load is lower than that of silicon brick due to the lack of mesh structure formed by mullite crystallization.
slag resistance
Due to high Al2O3 content of alumina brick, which is close to the neutral refractory, it can resist erosion of acid slag and alkaline slag erosion. However, as the existing of SiO2 in alumina brick, the ability of alkaline slag is weaker than that of acid slag.
It is mainly used for lining of blast furnace, hot air furnace, electric furnace top, blast furnace, reverberatory furnace and rotary kiln. In addition, high alumina brick is widely used as open hearth regenerative grid brick, plug head for pouring system, nozzle brick and so on. But the price of high alumina brick is higher than that of clay brick, so it is unnecessary to use high alumina brick where the clay brick can meet the requirements.
Physical and chemical index of General high alumina brick&fireclay brick | ||||||||||||
Properties | Products | |||||||||||
General high alumina brick | General fireclay brick | |||||||||||
LZ-75 | LZ-65 | LZ-55 | N1 | N2a | N2b | N3a | N3b | N4 | N5 | N6 | ||
Chemical Composition(%) | Al2O3 | 75 | 65 | 55 | 36-48 | |||||||
Fe2O3 | 2 | 2 | 2 | |||||||||
Physical Properties | Refratoriness (T0.6,℃) | 1790 | 1790 | 1770 | 1750 | 1730 | 1730 | 1710 | 1710 | 1690 | 1670 | 1580 |
linear change on reheating, 1500℃, 2h(%) | +0.1 -0.4 | 1400℃,2h℃ | 1400℃,2h℃ | |||||||||
+0.1 -0.4 | +0.1 -0.5 | +0.2 -0.5 | +0.2 -0.4 | +0.2 -0.5 | +0.2 -0.5 | +0.2 -0.5 | ||||||
Refratoriness under load (T0.6,℃) | 1520 | 1520 | 1520 | 1400 | 1350 | 1320 | 1300 | |||||
Apparent porosity(%) | 23 | 23 | 22 | 22 | 24 | 26 | 24 | 26 | 24 | 26 | 28 | |
Cold crushing strength(MPa) | 53.9 | 49.0 | 44.1 | 30.0 | 25.0 | 20.0 | 20.0 | 15.0 | 20.0 | 15.0 | 15.0 |