Handan Qifeng Carbon Explains Thermal Shock in Calcination Process

Handan Qifeng Carbon Co., Ltd. has provided an analysis of the phenomenon of thermal shock and its associated hazards during the calcination process. Thermal shock occurs when a material experiences rapid temperature changes, creating internal stresses due to differing expansion or contraction rates across its structure.

The mechanism involves uneven heating or cooling within the material, leading to temperature gradients. These gradients induce thermal stresses, and when these stresses surpass the material's tensile strength, cracks initiate. Factors influencing thermal shock include the material's coefficient of thermal expansion, elastic modulus, and the rate of temperature change. Additionally, phase transformations or mismatch at multiphase interfaces can exacerbate stress.

The hazards range from immediate fracture, potentially causing significant damage to large equipment like rotary kilns, to cumulative damage over repeated cycles. This can result in surface spalling, loss of strength, and fragmentation, particularly affecting refractory linings and shortening kiln service life. Such damage critically impacts the integrity and longevity of industrial heating equipment.

Furthermore, thermal shock can degrade product quality. For instance, alumina-based clinker or cathode materials may develop micro-cracks during calcination, negatively affecting their performance in subsequent applications. Improving thermal shock resistance typically involves selecting materials with lower thermal expansion coefficients and elastic moduli, alongside higher strength.