Calcining Limestone

Calcining limestone can also be used in a variety of industries, such as the construction industry, the steel industry, the chemical industry, the food industry, the paper industry, and so on. Bring more convenience and value to the industry.

What is Calcining Limestone

Calcining limestone is the process of breaking down the calcium carbonate in limestone by heating it at high temperatures, which then releases carbon dioxide to produce calcium oxide. CaCO₃→ CaO + CO₂. Limestone is firstly processed by pre-treatment, such as crushing, grinding, and preheating steps of limestone using a limestone crusher machine, limestone grinding mill, and cyclone preheater. Then enter the calcining limestone equipment, such as annular lime kilns, twin shaft lime kilns, double beam lime kilns, or limestone rotary kiln. After calcination at a high temperature to produce quicklime, it enters the cooling equipment after leaving the calcining limestone equipment to ensure the activity degree of lime. Lime has a wide range of applications, so calcining limestone can also be used in a variety of industries, such as the construction industry, the steel industry, the chemical industry, the food industry, the paper industry, and so on. Bring more convenience and value to the industry.

Calcining Limestone Process

The limestone blocks mined vary in size and need to be crushed to a uniform size, usually between 10-50 mm, using a limestone crusher machine. Uniform limestone size will lead to over-calculating limestone or underlining limestone. This affects the effectiveness and quality of calcining limestone.

Preheating is one of the most important steps in calcining limestone and a key step in energy conservation. Preheating limestone by recycling high-temperature exhaust gases saves combustion energy. Limestone can be heated up to 900°C in the preheating stage and part of the limestone is decomposed. It is then fed into the next major calcining limestone stage, effectively reducing the calcination time.

Calcining limestone is the most important step in the whole process. The preheated limestone is decomposed by 20-30% and the rest will be completely decomposed in the calcining stage. Insufficient calcining limestone temperature will lead to limestone not being completely decomposed; if calcining limestone temperature is too high, it will lead to lime activity degree is reduced, waste of energy.

Calcined lime reaches temperatures of up to 1,000°C. In order to ensure the activeness of the lime, it needs to be cooled quickly, usually to below 200°C. The hot air generated during the cooling process is recovered and returned to the cyclone preheater or kiln for the next preheating and calcining limestone, improving resource utilization and reducing fuel costs.

Application of Calcining Limestone

Construction Industry: In the construction industry, lime can be used to make cement and concrete, making building materials stronger and more durable. It can also be used to prepare lime mortar, walling, or plastering, which is breathable.
Environmental Protection Industry: Lime can be used to treat harmful substances in industrial wastewater, and can also be used as a desulfurization agent to reduce the pollution of the environment, protect the environment, and environmental protection production.
Agriculture: Limestone calcination produces quicklime that neutralizes the soil and changes its structure, thus enhancing its quality. It is also used as a fungicide to prevent soil diseases.
Paper Industry: Limestone calcination produces quicklime which can be used as a chemical agent and plays an important role in the alkaline pulping process to improve the quality and color of paper.

Calcining Limestone Equipment

The lime kiln is one of the most important equipment for limestone calcination and is used in many industries. AGICO offers different kinds of lime kilns to its customers. These include annular lime kilns, twin shaft lime kilns, double beam lime kilns, and limestone rotary kiln. We can meet the diversified needs of our customers. Our professional technicians can develop comprehensive solutions for customers in terms of output, energy consumption, cost, site, etc. AGICO has a complete one-stop service from design, manufacturing, and installation to after-sales service.

Annular Lime Kilns
Production Capacity: 100t/d – 600t/d
Limestone Particle Size: 30m-80mm
Lime Activity Degree: Greater than 360ml
Heat Consumption: No more than 950kcal/kg

Twin Shaft Lime Kilns (pfr lime kiln)
Production Capacity: 50-1200t/d
Limestone Particle Size: 30m-80mm
Lime Activity Degree: Greater than 360ml
Heat Consumption: No more than 860kcal/kg

Double Beam Lime Kilns
Production Capacity: 100t/d-600t/d
Limestone Particle Size: 30m-80mm
Lime Activity Degree: Greater than 320ml
Heat Consumption: No more than 1050kcal/kg

Limestone Rotary Kiln
Production Capacity: 200t/d-1200t/d
Limestone Particle Size: 20m-40mm
Lime Activity Degree: 360ml-400ml
Heat Consumption: About 1200kcal/kg