What is the calcination temperature of lime kiln shaft kiln
As an important equipment for producing lime, the control of calcination temperature in lime kilns plays a crucial role in the quality and production efficiency of lime. Understanding the appropriate calcination temperature range and the impact of temperature on lime quality can help optimize lime production processes, improve product quality, and increase economic benefits.
1、 Calcination temperature range
The calcination temperature of lime kiln shaft kiln is generally between 900-1200 degrees. Within this temperature range, limestone can undergo effective decomposition reactions to produce calcium oxide (i.e. lime). Different temperature stages have different effects and influences during the calcination process.
（1） 900-1000 degree stage
Within this temperature range, limestone begins to gradually decompose. As the temperature increases, calcium carbonate (CaCO3) begins to absorb heat and decompose into calcium oxide (CaO) and carbon dioxide (CO ₂). At this point, the decomposition reaction rate is relatively slow, but it has already laid the foundation for further decomposition in the future. This stage requires a certain amount of time to ensure that the limestone is fully heated and gradually initiate the decomposition process. If the temperature is too low and the decomposition reaction is incomplete, it will result in a large amount of undecomposed limestone remaining in the lime, thereby affecting the activity and quality of the lime.
（2） 1000-1100 degree stage
When the temperature enters the range of 1000-1100 degrees, the decomposition rate of limestone accelerates. A large amount of calcium carbonate rapidly decomposes, and the resulting calcium oxide crystals begin to gradually form and grow. At this stage, it is necessary to control the temperature rise rate and holding time reasonably to ensure the good development of calcium oxide crystals. Appropriate temperature conditions contribute to the formation of lime products with uniform structure and high activity. If the temperature fluctuates greatly or is too high, it may cause uneven growth of calcium oxide crystals, resulting in crystal structures that are too large or too small, affecting the subsequent performance of lime.
（3） 1100-1200 degree stage
When the temperature reaches 1100-1200 degrees, the decomposition of limestone is basically completed. The main task at this time is to further sinter and stabilize the generated lime. Appropriate high temperature can close some small pores in lime, increasing its density and strength. However, it should be noted that the temperature should not be too high, otherwise it may cause lime to overheat, resulting in a "dead burning" phenomenon, greatly reducing the activity of lime, and even making it difficult for it to react with other substances during use, affecting its application effect.
2、 The influence of temperature on the quality of lime
（1） The impact of low temperature
Incomplete decomposition
As mentioned earlier, too low a temperature can lead to incomplete decomposition of limestone, resulting in residual undecomposed limestone in the lime. This will not only reduce the effective calcium oxide content of lime, but also affect its chemical reactivity in subsequent applications. For example, in the construction industry, using this incompletely decomposed lime to make mortar or concrete may lead to problems such as insufficient strength and prolonged setting time, affecting the quality of the construction project.
Uneven quality
Lime calcined at low temperatures may result in uneven product quality due to incomplete decomposition reactions, where some areas have better lime quality while others have poorer quality. This unevenness can cause many inconveniences during use, such as in chemical production, which may affect the purity and consistency of the product, increase production costs, and make quality control more difficult.
（2） The impact of high temperature
Reduced activity
Excessive temperature can cause lime to overheat, resulting in an overly dense crystal structure of calcium oxide and a reduction in active sites, leading to a decrease in lime activity. In some application fields that require lime to have high activity, such as desulfurizers in steel smelting and sewage treatment agents in the environmental protection industry, overburned lime may not achieve the expected effect, requiring an increase in usage or the search for other alternatives, which increases production costs and process complexity.
Increased energy consumption
To maintain an excessively high calcination temperature, more energy, such as fuel, is required. This not only directly increases production costs, but may also cause greater pressure on the environment. Meanwhile, excessively high temperatures may also cause damage to kiln equipment, shorten its service life, and increase the cost of equipment maintenance and replacement.
The calcination temperature of lime kiln shaft kiln is generally controlled between 900-1200 degrees. Within this range, by adjusting the process parameters of different temperature stages reasonably, high-quality lime products can be produced. Low or high temperatures can have adverse effects on the quality of lime, leading to incomplete decomposition, uneven quality, or reduced activity, while also affecting production efficiency and costs. Therefore, in the process of lime production, it is necessary to strictly monitor and control the calcination temperature, combined with advanced temperature monitoring and regulation technology, to ensure that the temperature inside the kiln is stable within a suitable range, in order to achieve high-quality, efficient, and energy-saving lime production. Meanwhile, with the continuous development of technology and in-depth research, the optimization and control of calcination temperature will continue to be improved to further enhance the quality and performance of lime and meet the needs of different industries.
