Rotary kilns for expanded clay aggregate are widely used in industries such as clay, yellow mud, fly ash, shale, cement, limestone, and mineral powder. The main working principle of this equipment is as follows: The rotary kiln consists of a rotating drum, support bearings, a support device with thrust rollers, and sealing devices for the kiln head and tail, as well as a pulverized coal injection pipe system. The kiln body is inclined at a certain angle to the horizontal. The entire kiln body is supported by a roller support device, and a thrust roller device controls the vertical movement of the kiln body. In addition to the main drive, a device is also installed to ensure that the kiln body can still rotate slowly and prevent deformation when the main drive power is interrupted. The kiln head uses a shell-type seal, and the kiln tail is equipped with an axial contact seal device to ensure reliable sealing.

Rotary kiln calcination has the following characteristics:

1. High output: Rotary kilns are commonly used in large-scale lime production lines. Currently, internationally, rotary kilns can produce up to 2200 tons per day, while those commonly used in my country produce 150-300 tons per day. This series of rotary kilns exhibits good performance and stable operation.

2. The rotary kilns commonly used in domestic limestone production projects employ an open-type calcination process. The kiln structure is simple, airflow is unobstructed, and sulfur-containing flue gas can be discharged promptly. The resulting finished product has a low sulfur content, meeting the requirements for steelmaking. Furthermore, the material rolls and moves evenly within the kiln, ensuring uniform heating and stable, reliable product quality. The lime produced by rotary kilns also has high activity.

3. Rotary kilns can directly calcine fine-grained limestone of 10-50mm, offering convenience and speed. Generally, about 30-40% of limestone from typical mines has a particle size between 0-30mm, making this portion relatively difficult to process. Furthermore, with the “refining” of steel raw materials, quicklime is gradually replacing limestone in sintering, leaving fine-grained limestone underutilized. Constructing a rotary kiln production line not only fully utilizes high-quality limestone resources but also aligns with the sustainable development strategy of the lime industry.

4. Installing a vertical preheater at the kiln tail allows for full utilization of the high-temperature flue gas generated during calcination within the rotary kiln, preheating the limestone from ambient temperature to its initial decomposition temperature. This significantly increases the rotary kiln’s output and reduces heat consumption per unit product, lowering overall equipment energy consumption.

5. The vertical cooler in this series of equipment effectively improves product reactivity, ensuring quality during use and facilitating transportation and storage. It also effectively increases the temperature of the calcination zone within the kiln, reducing fuel consumption.

6. The exhaust gas has a low temperature and low dust content, which has an environmental protection effect.