The Influence Of Cement Kiln System On Refractory Materials

The stresses borne by refractory materials in the cement kiln system mainly include:
(1) Thermal stress;
(2) Chemical stress;
(3) Mechanical stress.
The damage of refractory lining is the result of the interaction of three stresses.
During the calcination process of clinker, the temperature of raw materials, kiln materials, and clinker is heated from room temperature to about 1430 ℃, and the combustion temperature of fuel in the kiln gradually decreases from 1800-2000 ℃ to below 350 ℃. During the cooling process of clinker, the clinker is cooled to about 100 ℃ by air, while the air is heated from room temperature to above 1000 ℃. During the above process, the radiation, convection, and heat transfer of flue gas, air, raw materials, kiln materials, and clinker to the lining and metal components are called thermal stress.
During the calcination process of cement clinker, various compounds in the raw materials and fuel undergo chemical reactions under different working conditions, resulting in the infiltration of solid, molten (liquid phase), and gas-phase compounds into the refractory lining and metal components. These compounds react with the compounds inside the lining and metal components to generate low melting temperature compounds that change in volume, causing damage to the lining and metal components, known as chemical stress.
During the calcination process of cement clinker, materials and dust containing gases move and transfer heat to the lining and metal components, causing them to be eroded and/or undergo volume expansion upon heating, resulting in stress damage to the lining and metal components, which is called mechanical stress. Mechanical stress can be appropriately reduced or eliminated through technological optimization.