Vertical kiln lime production process
Lime, as an important industrial raw material, has a wide range of applications in fields such as construction, metallurgy, and chemical engineering. Vertical kiln is one of the main equipment for producing lime, and its production process is relatively mature and has certain advantages.
1、 Overview of vertical kiln lime production process
The vertical kiln lime production process mainly includes the following steps:
（1） Raw material preparation
Limestone selection
Choose limestone with high calcium carbonate content, low impurities, and moderate particle size. Usually, the content of calcium carbonate in limestone should be above 90% to ensure the quality and yield of lime.
Raw material crushing
Crush large pieces of limestone into small pieces with a certain particle size, generally requiring a particle size between 40-80 millimeters, to facilitate calcination in a vertical kiln.
（2） Loading
The crushed limestone is uniformly loaded into the vertical kiln through a hoist or conveyor belt, and the uniformity of the loading has a significant impact on the airflow distribution and calcination effect inside the kiln.
（3） Calcination
Fuel selection
Commonly used fuels include coal, coke, natural gas, etc. The choice of fuel depends on cost, supply situation, and environmental requirements.
combustion control
By reasonably controlling the amount of fuel input and air supply, the temperature inside the kiln is maintained between 900 and 1200 ℃, allowing limestone to undergo decomposition reactions and generate lime and carbon dioxide.
Calcination time
The calcination time is determined by factors such as the particle size of limestone and the temperature inside the kiln, and generally takes 8-12 hours.
（4） Cooling
The lime after calcination needs to be cooled to prevent hydration reactions between high-temperature lime and air. There are natural cooling and forced cooling methods, and forced cooling can improve production efficiency.
（5） Discharge
The cooled lime is discharged from the kiln through the discharge device at the bottom of the kiln, and after screening, packaging and other processes, it becomes a finished product.
2、 Factors affecting lime production in vertical kilns
（1） Raw material quality
The composition, particle size, and impurity content of limestone directly affect the quality and yield of lime.
（2） Calcination temperature and time
High or low temperature, long or short time can all affect the activity and quality of lime.
（3） Ventilation conditions
Good ventilation can ensure sufficient combustion of fuel and uniform distribution of temperature inside the kiln.
（4） Uniformity of loading and fabric
Uniform loading and fabric can help improve the calcination effect and stability of product quality.
3、 Advantages and disadvantages of vertical kiln lime production process
（1） Advantages
The equipment structure is simple and the investment cost is relatively low.
Operation and maintenance are relatively easy.
Capable of adapting to different quality limestone raw materials.
（2） Disadvantages
Low thermal efficiency and high energy consumption.
The production capacity is relatively small.
The stability of product quality is relatively poor.
Although the vertical kiln lime production process has some drawbacks, its simple and flexible characteristics still make it have important application value within a certain range. By continuously optimizing process parameters, improving equipment, and strengthening management, the efficiency and quality of lime production in vertical kilns can be improved, meeting the needs of different industries for lime. The vertical kiln lime production process plays an important role in the lime industry, and relevant enterprises and technical personnel should continuously explore and innovate to promote its further development and improvement.
