What are the reasons for unqualified lime in rotary kilns
The quality of lime produced by rotary kilns is directly related to the application effect of subsequent products. However, in the actual production process, the lime produced by the rotary kiln may sometimes be found to be unqualified.
The quality of raw materials is the fundamental factor affecting the quality of lime. Limestone, as the main raw material, has significant effects on its quality due to its chemical composition, particle size, moisture content, and other characteristics. For example, if the impurity content in limestone is too high, such as silicon dioxide, aluminum oxide, etc., it will react with the generated calcium oxide to produce substances that are not conducive to the quality of lime; Particles that are too large or too small can affect the calcination effect of limestone, leading to a decrease in lime activity; If the moisture content is too high, a large amount of water vapor will be generated during the calcination process, which will lower the temperature inside the kiln and affect the degree of limestone decomposition.
Improper process operation is also an important reason for the unqualified lime. The process parameters such as calcination temperature, time, fuel type and ratio need to be adjusted reasonably according to the characteristics of the raw materials and production requirements. If the calcination temperature is too low or the time is insufficient, the decomposition of limestone will not be sufficient, which will lead to low lime activity; On the contrary, if the calcination temperature is too high or the time is too long, it may cause the lime to overheat, resulting in cracks or glassy shells on the surface, which affects the quality of the lime. In addition, unreasonable air supply can also lead to uneven calcination of lime, resulting in the occurrence of raw burning in some areas.
Equipment failure or design defects can also affect the quality of lime. For example, if the distance between temperature monitoring points in a rotary kiln is too large or the temperature measuring instrument is installed improperly, it can lead to large temperature control errors and affect the effectiveness of lime calcination; The calculation of material residence time does not take into account the influence of ring formation, and the actual residence time is shorter than the design value, which can also lead to insufficient lime calcination; If the replacement of the dust collector filter bag is delayed or the pressure difference monitoring data is inaccurate, it may cause harmful gas leakage and affect the purity of lime.
The reasons for the unqualified lime in rotary kilns involve multiple aspects such as raw material quality, process operation, and equipment failure. To ensure the quality of lime, it is necessary to control the quality of raw materials from the source, optimize process operating parameters, strengthen equipment maintenance and repair, and promptly identify and handle potential problems.
