Vertical Lime kiln calcination ensures stable quality of metallurgical lime
The stable quality of metallurgical lime calcined by lime kiln is the key to ensuring production efficiency and product quality in industries such as steel. To achieve this goal, precise control is required from multiple dimensions including raw materials, processes, equipment, and testing.
In the raw material process, strict screening of limestone is required to ensure that its CaCO3 content is ≥ 95%, impurity content is ≤ 3%, and the particle size is controlled within 20-80mm to avoid uneven particle size leading to uneven calcination. At the same time, smokeless coal or coke with stable calorific value is selected as fuel, and the fuel particle size is matched with limestone to reduce local over burning or under burning.
In terms of process control, layered fabric technology is adopted to ensure uniform distribution of materials in the kiln; Accurately adjust the air and fuel supply to maintain the temperature of the calcination zone in the kiln at 1050-1200 ℃, and ensure a stable calcination atmosphere through negative pressure monitoring at the kiln top. In addition, the ash discharge rate should be reasonably controlled to maintain the material's residence time in the kiln at 8-12 hours, ensuring sufficient decomposition of limestone.
In terms of equipment maintenance, regularly inspect the refractory materials of the kiln lining to prevent local air leakage; Maintain the fabric feeder and ash discharge device to avoid material segregation caused by mechanical failure. At the same time, install temperature and pressure online monitoring systems to real-time monitor the working conditions inside the kiln and adjust parameters in a timely manner.
In the quality inspection process, establish an hourly sampling system to test the activity of lime (required to be ≥ 300ml/4N HCl), CaO content (≥ 90%), and ignition loss rate (≤ 3%). If any abnormalities are found, they should be immediately traced and adjusted. Through refined management throughout the entire process, it is possible to achieve sustained and stable quality of metallurgical lime calcined in lime kilns, meeting the high requirements of industrial production.
