Effects of recycled corundum of different particle sizes on the properties of corundum castables

Effects of recycled corundum of different particle sizes on the properties of corundum castables

Recycled corundum is obtained through the recycling and reuse of waste refractory materials. It not only effectively saves resources and reduces production costs but also offers certain environmental benefits. However, due to the complex origins of recycled corundum, its composition and particle size distribution often vary significantly, directly affecting its application in corundum castables. The impact of recycled corundum of different particle sizes on the performance of corundum castables is mainly reflected in the following aspects:

Water Consumption

Experiments show that the water consumption of corundum castables increases significantly with decreasing particle size of recycled corundum. This is because fine-grained recycled corundum has a larger specific surface area, enabling it to absorb more water, thus increasing water consumption. Excessive water consumption not only increases production costs but also affects the workability and final performance of the corundum castable. Therefore, in practical applications, it is necessary to reasonably control the particle size of recycled corundum to balance the relationship between water consumption and performance.

Bulk Density and Strength

The particle size of recycled corundum has a significant impact on the bulk density and strength of corundum castables. The bulk density of corundum castables gradually increases with decreasing particle size. This is because fine-grained recycled corundum can fill more voids, improving the material’s compactness. Meanwhile, compressive strength and high-temperature flexural strength show a trend of first increasing and then decreasing; when the particle size of recycled corundum is moderate, the strength of the corundum castable is also good. However, when the recycled corundum particle size is too fine, the increased friction between particles leads to poor material flowability and increased construction difficulty. Simultaneously, excessive fine particles also increase the material’s porosity and reduce its strength.

High-Temperature Performance

Experiments show that as the particle size of recycled corundum decreases, the permanent linear change rate of corundum castables at 1500℃ gradually increases. This is because fine-grained recycled corundum is more prone to thermal expansion and contraction at high temperatures, resulting in greater dimensional changes in the material. High-temperature performance stability is crucial for refractory materials, as it directly affects their service life and safety under high-temperature conditions. Therefore, in practical applications, it is necessary to pay attention to the impact of recycled corundum particle size on high-temperature performance and take appropriate measures to improve the material’s high-temperature stability.

Slag Resistance

The particle size of recycled corundum also affects the slag resistance of corundum castables. Specifically, when the recycled corundum particle size is small (e.g., 5~1mm), the slag resistance of the corundum castable is poor. This may be related to the fact that fine-grained recycled corundum is more likely to react with slag at high temperatures. Therefore, in practical applications, it is necessary to avoid using excessively large or small recycled corundum particle sizes to improve the material’s slag resistance.

In summary, the impact of recycled corundum of different particle sizes on the performance of corundum castables is multifaceted. In practical applications, it is necessary to select the appropriate recycled corundum particle size based on the specific application environment and performance requirements. Furthermore, it is also necessary to optimize the performance of corundum castables through reasonable proportioning and process control to meet the needs of different fields.