- Time:Aug 21, 2023
Calcination of refractory materials refers to the heating treatment of the original refractory materials at high temperature, through chemical and physical changes, so that it can obtain the required structure and performance.
The principle of calcination involves the following aspects:
1. Crystalline phase transition: During the calcination process, some substances in the refractory may undergo a crystalline phase transition. This crystalline phase transition can change the material's crystal structure and lattice arrangement, thereby affecting its physical and chemical properties.
2. Sintering: During calcination, the particles in the refractory gradually come into contact, interact and form a tighter structure. At high temperatures, sintering occurs between the particles, where the surfaces of the particles bond together to form a strong structure. This sintering process increases the strength and compactness of the refractory.
3. Liquid Phase Formation: Certain refractories form a liquid phase during calcination. When certain components in the material reach the melting point, the formation of a liquid phase can fill the voids between particles, promote particle bonding and increase the density of the material. The formation of a liquid phase can also promote crystal growth and crystalline phase transition.
4. Exclusion of volatile matter: refractory materials may contain some volatile substances, such as moisture, organic matter, etc. During calcination, high temperatures cause these volatiles to evaporate or decompose, thereby being excluded from the material, increasing its stability and durability.
It should be noted that different types of refractories have different calcination conditions and requirements. Parameters such as temperature, time and atmosphere of the calcination process need to be optimized and controlled according to the characteristics and required performance of the specific material.
