Lightweight Insulating Brick Description
Lightweight insulating bricks are shaped refractory products with multi-pore structure. Lightweight insulating bricks can be classified into lightweight clay bricks, lightweight silica bricks, lightweight high alumina bricks and so on.
Lightweight clay insulating bricks
Lightweight clay insulating bricks’ main materials are clay clinker, lightweight clinker or plastic clay, which contains 30%~46% of Al2O3. Light weight clay bricks are usually produced by combustible material burning method, chemical method or foaming method to form multi pore structure. The prepared materials need to mix with water and become plastic clay or slurry state, and then molded into brick shape by squeezing method or casting method. After the green bodies are dried, they will be burned in oxidative atmosphere at 1250℃~1350℃. The bulk density of lightweight clay bricks is usually between 0.75~1.20g/cm3, compression strength is between 2.0~5.9Mpa, thermal conductivity rate is between 0.221~0.442W/(m.K) (1350℃). Lightweight clay bricks have a wide range of applications, mainly used as insulating layers material for various kinds of industrial kilns and furnaces, which will not contact with molten material or corrosive gas directly. The working temperature of light weigh clay bricks is between 1200℃~1400℃.
| Item | LCB-1.5 | LCB-1.3 | LCB-1.0 | LCB-0.7 | LCB-0.5 |
| Bulk density g/cm3≤ | 1.5 | 1.3 | 1.0 | 0.7 | 0.5 |
| Cold compression strength Mpa ≥ | 5.9 | 3.9 | 2.9 | 2.0 | 1.2 |
| Linear change test temperature ℃ | 1400 | 1350 | 1350 | 1250 | 1150 |
| Thermal conductivity rate /w.(m.K)-1 350±25℃ ≤ | 0.70 | 0.60 | 0.50 | 0.35 | 0.25 |
Lightweight high alumina bricks
Lightweight high alumina bricks is the kind of insulating bricks with more than 45% of Al2O3. There are generally two kinds of lightweight high alumina bricks, one is ordinary lightweight high alumina bricks which is made from natural high alumina bauxite clinker, the other is high quality lightweight high alumina bricks made from fused or sintered alumina, it’s principle crystalline phase is corundum, so it is also called lightweight corundum bricks.
Lightweight high alumina bricks are usually made by foaming method and sintered at 1350~1500℃. The bulk density of lightweight high alumina bricks is between 0.4~1.35g/cm3, apparent porosity is between 66%~73%, compression strength is between 1.3~8.1Mpa, thermal conductivity rate is between 0.291~0.582 W/(m.k) (350℃).
Light weight high alumina bricks have high refractoriness, good thermal shock resistance, are usually used as high temperature insulating layers of industrial kilns and furnaces. High quality lightweight high alumina bricks can also be used as inner lining of industrial kilns and furnaces, where can directly contact with fire. But lightweight high alumina bricks are not suitable for places where contact with slag directly.
