Alumina bubble insulating brick
Alumina bubble insulating bricks are insulating refractories made from alumina bubbles, alumina powders, binders and additives. Alumina bubble bricks are mainly used at applications with a temperature up to 1800℃, such as insulating lining of high temperature industrial kilns and high temperature thermal equipment.
Bubbles in bricks can significantly reduce thermal conductivity, therefore, alumina bubble bricks have excellent thermal insulating properties, while keeping high hot strength. Besides, bubble alumina bricks also have good resistance to weak acid and weak alkali corrosions.
Alumina bubble insulating bricks production method
The production method of alumina bubble bricks is: first, alumina raw material is charged into electric furnace and melted into liquid, then furnace tilts to certain angle, so molten alumina liquid flows out at certain speed, at the same time, 0.6~0.8Mpa high speed air current with 60~90° angle blows liquid alumina into alumina bubbles. Next, alumina bubbles, calcined alumina powder and binding agent are proportionally formulated, molded, dried, sintered and finally alumina bubble bricks are produced.
Alumina bubble bricks advantages
Alumina bubbles have high refractoriness, The working temperature of high purity alumina bubble bricks made from fused alumina is up to 1800℃.
Good thermal insulating effect and strong resistance to thermal shock.
Low bulk density, the total weight is reduced.
Weak acid and weak alkali corrosion resistant.
Alumina bubble bricks physiochemical indexes
| Item | LKZ-85 | LKZ-90 | LKZ-99 |
| Max. working Temperature ℃ | 1680 | 1700 | 1800 |
| Al2O3% | ≥85 | ≥90 | ≥99 |
| SiO2% | ≤15 | ≤8 | ≤0.2 |
| Fe2O3% | ≤0.2 | ≤0.2 | ≤0.2 |
| Bulk Density g/cm3 | 1.4-1.7 | 1.4-1.7 | 1.4-1.7 |
| Cold Crushing Strength MPa | ≥12 | ≥10 | ≥9 |
| Refractoriness Initial Under Load (0.1MPa, 0.6%) ℃ | ≥1650 | ≥1760 | ≥1760 |
| Reheating Linear Change Rate (1600℃*3h) % | ±0.3 | ±0.3 | ±0.3 |
| Heat Expansion Coefficient (Room temperature -1300℃) | ~7.8 | ~8.0 | ~8.6 |
| Thermal Conductivity (Average temperature 800℃ ) w/(m*k) | ≤0.8 | ≤1.3 | ≤1.5 |
Alumina bubble bricks applications
Alumina bubble bricks are often used as ceramic kilns inner lining, gasifier backup lining, hazardous waste and fluorine processing incinerators, hydrogen generators, thermal reactors for methanol production, and ammonia reformers.