1. The influence of heat treatment temperature on the organization of corundum-based refractory materials
As the heating temperature increases, the calcium aluminate binder component in the refractory corundum-based materials will change. Specifically, calcium aluminate (CaAl2O4, referred to as CA) will gradually transform into CaAl4O7 (referred to as CA2). This transformation process has a significant impact on the microstructure of the refractory materials:
1. Sintering of fine ceramic particles: As the temperature increases, the fine ceramic particles in the refractory materials will gradually sinter together to form a stable network structure that is interconnected. The formation of this structure helps to improve the overall strength and stability of the refractory materials.
2. Coating of large-particle aggregates: During the transformation process, the calcium aluminate binder will gradually wet and spread on the large-particle aggregates and connect with each other, and finally form a coating of the large particles. This coating effect helps to reduce the gaps between large-particle aggregates and improve the density and erosion resistance of the refractory materials.
2. Effect of heat treatment temperature on particle shedding of corundum-based refractories materials
Heat treatment temperature not only affects the organizational structure of corundum-based refractory materials, but also has a significant effect on their particle shedding performance:
1. Enhancement of particle adhesion: As the heating temperature increases, the adhesion of refractory particles will gradually increase. This is mainly due to the transformation of calcium aluminate binder and the sintering of fine ceramic particles, which makes the internal bonding force of the refractory material tighter.
2. Reduction of particle shedding: Under the condition of 60 minutes of insulation, when the heating temperature is 1150-1130, the particle shedding is significantly reduced. Among them, 1250-1350℃ is considered to be the optimal preheating temperature section. Within this temperature range, the microstructure of the refractory material is optimized, and the bonding force between the particles is enhanced, thereby reducing the shedding of particles.
3. Effect of heat treatment temperature on other properties of corundum-based refractory materials
Although the heat treatment temperature has little effect on the apparent porosity, bulk density and overall thermal shock resistance of corundum-based refractories, the local shedding degree and mass loss rate of the refractory surface in the thermal shock test are significantly improved with the increase of temperature. This further proves the positive effect of heat treatment temperature on the particle shedding performance.
In summary, the heat treatment temperature has a significant effect on the organization and particle shedding performance of corundum-based refractories. By reasonably controlling the heat treatment temperature, the microstructure of the refractory can be optimized and the bonding force between the particles can be enhanced, thereby reducing the shedding of particles and improving the overall performance of the refractory.
