Storage period and precautions for lime production raw materials
The main raw materials for lime production are limestone and fuel (such as coal), and their physical and chemical properties may change during storage, directly affecting the calcination process and product quality. Scientific planning and storage strategy is a key technical link to ensure production stability.
The storage of limestone requires special attention to its moisture absorption and weathering characteristics. When stored outdoors for a long time, the surface of limestone absorbs atmospheric moisture and reacts with carbon dioxide, resulting in mild pulverization of the surface and the formation of a hard shell of calcium carbonate. Although this process does not affect the internal mineral structure, it will slightly increase the energy consumption of calcination. In theory, limestone has stable chemical properties and no absolute storage period. However, if crushed and stored for a long time, fine particles are more likely to adsorb moisture and impurities due to their increased specific surface area. It is recommended that the storage period of the crushed material pile should not exceed six months. The yard design should have a good drainage slope, and the height of the material pile should not exceed five meters to prevent the bottom material from clumping due to long-term pressure.
As a common fuel, coal's storage core lies in preventing spontaneous combustion and heat value decay. The temperature inside the coal pile may gradually accumulate due to microbial activity and oxidation heat release. When the local temperature exceeds 60 degrees Celsius, the risk of spontaneous combustion significantly increases. The storage period is generally controlled within three months, and for high volatile coal types, the storage period should be further shortened. Coal piles should be compacted and formed to reduce internal air pores, and a regular temperature measurement system should be established. The temperature monitoring point should be vertically penetrated into the interior of the reactor, and any abnormal temperature rise should be promptly reversed for heat dissipation.
Auxiliary materials such as desulfurizers usually have higher chemical activity and stricter requirements for storage environment. This type of material must be stored in a dry and sealed warehouse, isolated from the air. The storage period should generally not exceed one month, and the first in, first out principle should be followed when using it.
A complete quality tracking system needs to be established for raw material storage management. Record the initial indicators and stacking time for each batch of incoming raw materials, regularly sample and detect changes in moisture content and composition, provide data support for adjusting kiln operating parameters, and stabilize clinker production quality from the source.
