Phosphate bonded high-alumina bricks
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Product Introduction
Phosphate-bonded high-alumina brick is a refractory material with phosphate as a bonding agent, phosphate-bonded high-alumina brick contains a large amount of α-Al2O3, mixed with phosphoric acid, aluminum phosphate and pyrophosphate are generated in a certain temperature range, these substances have a stable structure at less than 1500 °C, showing good wear resistance, thermal stability and high temperature strength.
Since the content of Al2O3 is generally more than 80%, Al2O3 plays a dominant role in chemical thermodynamic properties. The affinity of CaO for oxygen is greater than that of Al, and that of Si is less than that of Al, but the eutectic can only be formed at 1440°C, which provides a theoretical basis for the use of phosphate-bonded high-alumina bricks in the pre-tropical belt, decomposition zone and cooling zone.
The structure of the main mineral components is of the form of cristobalite AlPO4, which is stable before decomposition into Al2O3. However, above 1500°C, AlPO4 gradually decomposes, affecting the high-temperature performance and causing a sharp decrease in the thermal intensity.
The refractory ≥ 1970 °C, the temperature of the 2kgf/cm2 load softening point is greater than 1350 °C, the bulk density ≥ 2.75g/cm³, and the compressive strength at room temperature ≥ 61.8MPa.
Phosphate-bonded high-alumina bricks are suitable for the transition zone kiln mouth of the rotary kiln and other parts that are easy to drop bricks, and are also used in the firing zone. Wear-resistant bricks are suitable for the cooling belt, kiln mouth and cooler of the rotary kiln.
By impregnation of ordinary high-alumina bricks in phosphate or phosphoric acid solution, the quality of high-alumina bricks can be improved and their service life can be prolonged. After phosphate or phosphoric acid impregnated high-alumina bricks, the load softening temperature increases, the porosity decreases, the density of refractory bricks increases, and the flexural strength increases.
Phosphate-bonded high-alumina bricks have a wide range of application prospects in high-temperature industry because of their excellent fire resistance and mechanical properties.
| Projects | Physical and chemical indicators | |||||
| P (Phosphate Brick) | PA (Wear Resistant Brick) | |||||
| Ⅰ | Ⅱ | Ⅰ | Ⅱ | |||
| chemical composition | Al2O3/% | ≥ | 75 | 77 | ||
| Fe203/% | ≤ | 3.2 | 3.2 | |||
| CaO/% | ≤ | 0.6 | 0.6 | |||
| Compressive strength at room temperature/Mpa | ≥ | 70 | 60 | 75 | 65 | |
| Bulk density/(g/cm3) | ≥ | 2.70 | 2.65 | 2.75 | 2.70 | |
| Load softening temperature T0.6/°C | ≥ | 1350 | 1300 | 1300 | 1250 | |
| Thermal shock stability (1100°C, water cooling)/time | ≥ | 10 | ||||
Key words:
Phosphate bonded high-alumina bricks
High-alumina bricks
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