Magnesium Alumina Spinel Fire Brick is a high-grade basic refractory material with periclase and spinel as the main minerals, which is formed by high pressure molding and high temperature sintering, and at the same time adding a specific mineralizer to improve the internal structure of the product. The service life of Magnesium-aluminum spinel brick in the new dry process cement kiln of 5000T/D cement clinker can reach more than 12 months
Compared with magnesia bricks, magnesia alumina bricks have the following characteristics:
①Magnesia-alumina bricks have good thermal shock stability and can withstand water cooling for 20 to 25 times, or even higher. This is its most prominent advantage, much better than ordinary magnesia bricks. The study believes that the thermal shock stability of magnesia-alumina bricks is good because magnesia-alumina spinel and periclase belong to the cubic crystal system, and the thermal expansion along each crystal axis direction is the same, so the expansion and contraction are relatively uniform when the temperature fluctuates. The resulting thermal stress is small.
② The main properties of magnesia-alumina bricks are also slightly stronger than those of magnesia bricks. Due to the high melting point of magnesia-alumina spinel itself, the softening temperature of magnesia-alumina bricks under load is improved compared with magnesia bricks, reaching 1620-1690 °C.
The ability of magnesia-alumina spinel to protect periclase particles from slag erosion is stronger than that of calcium forsterite, so the ability of magnesia-alumina brick to resist alkaline slag and iron oxide slag is stronger than that of magnesia brick.
Magnesia alumina brick has the above excellent properties, so it has been widely used in our country as the masonry material for the top of high temperature melting furnaces such as steel-making open hearth, copper-smelting reverberatory furnace, etc., and has achieved the effect of prolonging the life of the furnace. Large open hearth furnaces can reach about 300 furnaces, and small and medium-sized open hearth furnaces can exceed 1000 furnaces
| Model | MA-6 | MA-7 | MA-8 | |
Chemical Composition (%) | MgO | ≥85 | ≥86 | ≥86 |
| Fe2O3 | ≤0.8 | ≤0.7 | ≤0.7 | |
| AL2O3 | 11-13 | 10-12 | 10-12 | |
| SiO2 | ≤0.7 | ≤0.5 | ≤0.35 | |
| CaO | ≤1.30 | ≤1.10 | ≤0.95 | |
| Bulk density(g/cm³) | ≥2.95 | ≥2.97 | ≥3.0 | |
| Apparent Porosity(%) | ≤16 | ≤16 | ≤16 | |
| Compressive Strength(Mpa) | ≥65 | ≥65 | ≥65 | |
| Refractoriness under Load ℃(0.2Mpa,t0.6) | ≥1700 | ≥1700 | ≥1700 | |
| Thermal shock stability, times (1100℃, water cooling) | ≥12 | ≥12 | ≥12 | |
