Jun 30, 2021
Mullite Refractory Bricks
Mullite Bricks Characteristics
Good thermal shock resistance
Low high temperature creep rate
Good acid and weak alkaline slag corrosion resistance.
High refractoriness and mechanical strength.
Sintered mullite bricks
Sintered mullite bricks adopt synthesized mullite aggregates, and fines, or white corundum, quartz, and pure clay powder mixture with the same chemical composition of mullite. The raw material is evenly mixed, then molded under high pressure, and finally sintered at the temperature of 1550~1600℃.
Sintered mullite bricks physiochemical index
| Item | Hot blast furnace mullite brick | Stopper head mullite brick | Blast furnace wall brick | Fused synthesized mullite brick |
| Al2O3 % | 80.0 | 68.3 | 72.0 | 75.1 |
| SiO2 % | 18.2 | — | — | 20.1 |
| Fe2O3 % ≤ | 0.76 | 0.84 | 1.7 | 3.35 |
| Apparent porosity % | 15.6-16.5 | ≤16.7 | ≤22 | 12-16 |
| Cold compression strength/Mpa | 197-267 | ≥77 | ≥49 | 210-250 |
| Rupture under load/℃ | ≥1700 | ≥1600 | ≥1650 | ≥1700 |
| Bulk density g/cm3 | 2.77-2.79 | 2.53 | 2.68 | 2.56-2.66 |
Fused cast mullite bricks
Fused cast mullite bricks’ main raw materials are high alumina bauxite or industrial alumina, clay, or silica with proper ratio. The mixed material is melted in electric arc furnaces, cast into shape, and then annealed to make the final mullite bricks. The main mineral ingredient of fused cast mullite bricks is mullite, which’s chemical composition is 3Al2O3·2SiO2.
Fused cast mullite bricks physiochemical property
| Item | Hot blast furnace mullite brick |
| Al2O3 % | 70.1-75.47 |
| SiO2 % | 19.32-21.6 |
| Fe2O3 % | 0.92-1.90 |
| Apparent porosity % ≤ | 10 |
| Cold crushing strength/Mpa | 250-500 |
| Rupture under load/℃ | 1700 |
| Bulk density g/cm3 | 2.9-3.3 |
| Refractoriness ℃ | 1730-1800 |
| Thermal expansion rate %(20-1000 ℃) | 0.60-0.65 |
Mullite Bricks Applications
Mullite bricks are mainly used in the inner lining of various parts of thermal kilns and furnaces for different industries, such as the steel and iron industry, chemical industry, glass industry, ceramic industry, and so on. For example, mullite bricks are widely used in hot blast furnaces for iron making, used in glass kiln main body feeding channel, regenerative chamber, clarification tank wall. Mullite bricks are also used in rotary cement kiln and rotary lime kiln inner lining. The physiochemical index of mullite bricks is different for different applications.
More Details