Product Introduction
Active lime rotary kiln is a special equipment used to calcine high-quality limestone to produce active lime (i.e. calcium oxide, CaO). Active lime refers to calcium oxide with high reactivity, which is usually used in steel, chemical industry, building materials and other fields. Active lime rotary kiln ensures that the produced lime has high activity and excellent physical and chemical properties through precise temperature control and efficient calcination process.
Structural composition
1. Cylinder: The core part of the rotary kiln, usually made of high temperature and corrosion resistant steel plate, lined with refractory bricks or refractory materials inside to prevent high temperature from damaging the kiln body.
2. Transmission system: including motor, reducer and large gear ring, used to drive the rotation of the rotary kiln to ensure uniform movement of materials in the kiln.
3. Support wheel device: used to support the kiln body and ensure the smooth operation of the kiln body.
4. Combustion system: Provides the high-temperature heat source required for calcination. The fuel usually uses coal, natural gas or heavy oil. Modern kilns also use environmentally friendly fuels such as waste gas or biomass fuel.
5. Cooling system: used to quickly cool the calcined calcium oxide, usually a grate cooler or countercurrent cooling device.
6. Exhaust gas treatment system: including dust collector and gas purification device to ensure that the exhaust gas generated during the calcination process meets the environmental emission standards.
Table of Contents
Working principle
1. Feeding: Limestone is evenly fed into the kiln head of the rotary kiln through a conveying device. The size of the limestone blocks is usually screened to ensure the uniformity of calcination.
2. Preheating: Before entering the high-temperature calcination zone, the limestone will pass through the preheating zone in the kiln, and the waste heat of the combustion gas will be used to preheat the limestone to about 800℃. At this time, part of the calcium carbonate begins to decompose, reducing the heat energy consumption required for calcination.
3. High-temperature calcination: In the high-temperature zone of the rotary kiln, the limestone is further heated to about 900℃-1100℃, and the high temperature causes the calcium carbonate to completely decompose into calcium oxide (quicklime) and carbon dioxide.
1.CaCO₃ + high temperature → CaO + CO₂↑ This process requires the temperature in the kiln to be kept uniform to ensure sufficient calcination and increase the activity of the lime.
4. Cooling: After calcination, the generated calcium oxide is quickly cooled down by the cooler to maintain its high activity. The cooled active lime is discharged from the tail of the kiln for subsequent applications.
5. Tail gas treatment: The waste gas (mainly CO₂ and some dust) generated during the calcination process is purified by the tail gas treatment device to ensure that the emission meets environmental protection standards.
Application areas
Steel industry
Active lime is widely used in metallurgical chemical reactions such as desulfurization, dephosphorization and desiliconization in the steelmaking process to improve the quality of steel.
Chemical industry
It is used to prepare chemical products such as calcium carbonate, calcium hydroxide, calcium salts, and is also used as an acid-base neutralizer.
Building materials
Active lime can be used to make building materials such as concrete, gypsum, mortar, etc., to enhance the durability of building materials.
Environmental protection
As a precipitant in sewage treatment, it is used to neutralize acidic wastewater, and is also used for flue gas desulfurization to reduce sulfur dioxide emissions.
Others
It is also widely used in leather, papermaking, food and other industries.
Advantages
1. High calcination efficiency: The rotary kiln calcines evenly, has high thermal energy utilization, and the produced lime has high activity and purity.
2. Good environmental performance: Through the exhaust gas treatment and heat recovery system, the emission of pollutants is effectively reduced, which meets the environmental protection requirements.
3. Stable operation: The rotary kiln runs smoothly, the equipment wears less, and a continuous and stable working state can be maintained during the production process.
4. Good product quality: The reactive activity of active lime is high, which meets the demand for high-quality lime in metallurgy, chemical industry and other industries.