The continuous production of mechanical lime shaft kiln relies on the reverse movement of materials and airflow. The kiln body is divided into three stages from top to bottom: preheating, calcination, and cooling. Limestone and fuel are evenly added from the kiln top distributor in proportion and slowly move downwards under the action of gravity; The combustion air is forcibly blown in from the bottom of the kiln and penetrates the material layer from bottom to top. The two come into reverse contact, forming a stable heat exchange.
The calcination zone is the core area of the reaction. Limestone undergoes thermal decomposition here: CaCO ∝→ CaO+CO ₂ ↑. Mechanized shaft kiln precisely controls the position and temperature of the calcination zone (1100-1200 ℃) by adjusting the air flow rate and lime discharge speed. If the lime is unloaded too quickly, the calcination zone will move downwards and lime will be burned; If it is too slow, it will move up and be prone to tumor formation. Therefore, the key to continuous production is the coupling of "uniform lime discharge" and "stable air supply".
The bottom of the kiln adopts a tower or disc type lime unloader, which is driven by hydraulic or mechanical power and continuously discharges hydrated lime at a set speed. The amount of lime discharged directly determines the descent speed of the material column, which in turn affects the residence time of the material in the kiln. At the same time, the kiln top material distributor rotates and spreads materials to minimize particle size segregation and ensure uniform airflow distribution.
The entire system forms a closed loop: lime unloading → material level lowering → fabric distribution → fresh air entering → calcination → cooling → lime unloading. Sensors monitor kiln temperature, air pressure, and material level in real-time, while PLC automatically adjusts lime discharge speed and air volume to achieve continuous operation with stable production, high quality, and low consumption. Mechanized vertical kilns have thus freed themselves from manual intermittent operations and become efficient and controllable continuous reactors.
