- Time:Aug 25, 2023
Calcination of refractory raw materials is an important step in the process of refractory preparation, and it has the following functions:
1. Crystalline phase formation: Minerals in refractory materials undergo a process of crystalline phase formation at high temperatures. During the calcination process, the compounds and oxides in the original material react chemically, transform into a crystalline phase, and form a uniform and dense grain structure through the crystallization process. These crystalline phases endow refractory materials with desired physical and chemical properties, such as high temperature stability, thermal shock resistance, etc.
2. Increased hardness and strength: After the refractory raw materials are calcined, the crystal structure is enhanced, and more bonding points and connections are formed between the grains. This leads to a significant increase in the hardness and strength of the refractory material, allowing it to withstand mechanical and thermal stress in high-temperature environments, preventing cracking and damage.
3. Exclude moisture and volatiles: refractory raw materials usually contain a certain proportion of moisture and volatile components. During the calcination process, the high temperature drives away moisture and volatile matter from the raw material, so that the refractory material can obtain lower water content and volatile matter content. This is very important because the presence of moisture or volatile components at high temperatures can cause the refractory to burst or lose stability during service.
4. Dimensional stability: The calcination process can change the volume and size of refractory raw materials, and achieve stable shape and size through rearrangement of crystal structure. This is very important for the assembly and application of refractory materials, ensuring its precise fit with other components, providing good sealing performance and structural stability.
5. Special performance control: During the calcination process, the special performance of the refractory material can be controlled by adjusting the calcination process parameters (such as temperature, time, etc.). For example, the calcination process can improve the corrosion resistance, thermal conductivity, electrical conductivity, etc. of refractory materials to meet the needs of specific applications.
In short, the calcination of refractory raw materials is a key step in the preparation of refractory materials. Through heat treatment and changes in crystal structure, refractory materials are endowed with the required physical, chemical and mechanical properties to meet the requirements for use in high-temperature environments.
