Detailed explanation of the principle of rotary kiln technology
Rotary kiln is a core thermal equipment in industries such as building materials and metallurgy, which uses a tilted rotating cylindrical structure to achieve continuous calcination of materials. The core principle revolves around "high-temperature heat exchange+physical and chemical conversion", and the process is divided into three stages: preheating, calcination, and cooling.
Preheating stage: Materials (such as cement raw materials, iron ore) enter from the kiln tail feeding device and flow in reverse with the high-temperature flue gas generated by the combustion at the kiln head. With the help of the material flipping caused by the rotation of the kiln body, the heat from the flue gas is efficiently transferred to the material, raising the temperature of the material to 800-900 ℃, completing pre-treatment such as water evaporation and carbonate decomposition, and reducing energy consumption for subsequent calcination.
Calcination stage: The middle section of the kiln body (burning zone) is sprayed with fuel through a coal injection pipe for combustion, forming a high temperature zone of 1300-1600 ℃. The rotating kiln body slowly moves forward with animal materials, and complex chemical reactions occur at high temperatures (such as the formation of calcium silicate minerals from cement raw materials and the reduction of iron ore). At this stage, precise control of kiln speed (usually 3-5 r/min) and combustion temperature is required to ensure that the material reacts fully and does not clump.
Cooling stage: The high-temperature material (such as cement clinker) that has been calcined enters the kiln head cooling machine and is cooled to below 200 ℃ through forced heat exchange with cold air. During the cooling process, hot air is recovered into the kiln for combustion assistance, achieving energy recycling. The cooled material is then discharged through the conveying system and enters the subsequent processing stage.
The entire process relies on the coordination of kiln inclination angle (usually 3% -5%) and rotational motion to ensure uniform material movement and heat exchange. At the same time, product quality stability and energy consumption optimization are achieved through parameter control such as temperature and kiln speed.
