What Is Vertical Shaft Kiln Process? Step-by-Step Lime Production Guide
Lime vertical kiln is a widely used core equipment for limestone calcination in the industrial field. With the principle of countercurrent heat transfer, it achieves efficient and continuous production, and has the advantages of high thermal efficiency, low operation and maintenance costs, and adaptability to multiple fuels. It is currently one of the mainstream process routes for active lime production.
The first step is precise preparation of raw materials. Strictly screen high-quality limestone with a calcium carbonate content of over 90%, and stabilize the particle size within the range of 40-80mm through crushing and screening processes. At the same time, process smokeless coal or coking coal and other fuels to the appropriate particle size, and complete uniform mixing in a reasonable ratio of 10:1 to 15:1 to ensure the stability of subsequent calcination from the source.
The second step is to seal and load the material into the kiln. The mixed materials are transported to the top material bin of the kiln by a bucket elevator, and evenly distributed into the kiln through an intelligent rotating material feeder. The material surface in the kiln is maintained flat throughout the process, avoiding local voids or deviations, and ensuring uniform airflow resistance across the entire kiln cross-section.
The third step is gradient temperature control calcination. The material slowly descends under the action of gravity and passes through three major functional zones in sequence: the preheating zone uses the rising high-temperature exhaust gas to preheat the raw material to the decomposition critical point; The core calcination zone is precisely controlled at 1050-1150 ℃, allowing limestone to fully decompose into highly active calcium oxide; The cooling belt utilizes cold air blown in from the bottom to cool the finished lime, while recovering waste heat to preheat the combustion air, greatly improving heat utilization efficiency.
The fourth step is environmentally friendly discharge and storage. The cooled finished product is stably discharged through a continuous ash discharge mechanism and sent to the finished product warehouse through conveying equipment. The entire process is equipped with environmental protection devices such as bag dust removal, and the exhaust emissions fully comply with current industry standards. The final output of lime has high activity and low raw firing rate, and can be directly supplied to downstream industries such as metallurgy and building materials.
