Improving the performance and service life of corundum castables is an important issue in the field of refractory research.
1.Basic characteristics of corundum castables
Corundum castable is a high-performance refractory material made of alumina (Al2O3) as the main raw material through high-temperature firing. It has excellent properties such as high melting point (2050℃), high hardness, and high chemical stability. It can withstand high temperatures up to 1700℃, and within this temperature range, its volume stability, creep resistance, and thermal shock resistance are very excellent. In addition, corundum castable also exhibits extremely strong corrosion resistance and can resist the corrosion of various acids, alkalis, salts and other chemical substances.
2.Methods to improve the performance of corundum castables
（1）Optimize raw material formula:
- High-purity alumina raw materials are used to ensure the Al₂O₃ content in the corundum castable, thereby improving its refractoriness and chemical stability.
- Add appropriate amounts of binders and aggregates, such as SiO₂ micropowder, α-Al₂O₃ micropowder and other active fillers to optimize the particle ratio and mineral combination, and improve the density and mechanical strength of the material.
（3）Introducing special additives:
- Adding AMC composite material: AMC composite material is a unique material made of industrial alumina as the main raw material, mixed with MgO and CaO components recovered from steelmaking waste slag. By adding AMC composite material, its good thermal shock stability and slag resistance can be used to improve the strength of the steel-passing area of corundum castables. Tests have shown that adding 30% AMC composite material to corundum castables can greatly improve its thermal shock stability and reduce the occurrence of cracks, thereby extending its service life.
- Add other oxide refractory materials: such as Cr₂O₃, ZrO₂, etc., to change the performance of corundum refractory castables and improve their corrosion resistance and mechanical strength.
3.Improved manufacturing process
- Use advanced mixing and molding technology to ensure uniform mixing of raw materials and molding quality.
- Optimize the sintering process, control the sintering temperature and holding time to obtain a dense sintered body and good microstructure.
3.Ways to improve the service life of corundum castables
1.Enhanced corrosion resistance:
- By optimizing the raw material formula and adding special additives, the corrosion resistance of corundum castables is improved, making it able to withstand various highly corrosive environments, such as kilns and equipment linings in steel smelting, non-ferrous metal smelting, chemical, glass and other industries.
2.Improved thermal shock stability:
- Raw materials and additives with high thermal shock stability, such as AMC composite materials, are used to improve the thermal shock stability of corundum castables and reduce cracks and spalling caused by sudden temperature changes.
3.Optimize particle ratio
- Through reasonable particle ratio and mineral combination, the density and mechanical strength of corundum castables can be improved, so that it can withstand harsh conditions such as high temperature, high pressure, and high corrosion.
4.Strengthen quality inspection and maintenance:
Strict quality inspection is carried out on the corundum castable to ensure that its performance meets the use requirements. During use, maintenance and care are strengthened to timely discover and deal with potential problems to extend the service life.
4.Application Examples and Effects
By trying the corundum castable with 30% AMC composite material on a 120t ladle in a steel plant, its practical life has reached 40 times, and good results have been achieved. This not only reduces production costs, but also effectively increases the service life of the ladle seat bricks. This example fully proves the effectiveness of optimizing the raw material formula and adding special additives to improve the performance and service life of corundum castables.
To sum up, improving the performance and service life of corundum castables requires optimizing raw material formulas, introducing special additives, improving manufacturing processes, and strengthening quality inspection and maintenance. Through the implementation of these measures, the refractory resistance, corrosion resistance, mechanical strength and thermal shock stability of corundum castables can be significantly improved, thereby extending their service life and reducing production costs.
