Limestone Crushing and Raw Meal Ingredients - Cement Plant
Limestone Crushing Process
Limestone is crushed in section 1 crushing process. then it is discharged into the hopper by truck, heavy-duty plate feeder is placed under the hopper, and limestone is evenly fed into the single-rotor impact crusher. Then crushed gravel is sent to the limestone pre-homogenization silo by belt conveyor. It is then sent to the limestone silo of the raw material batching station for use. If limestone is purchased instead of produced at site, it is first stored in the limestone open-air yard, then taken by the dumper and sent to the limestone silo via the limestone belt, and then delivered to the limestone pre-homogenization silo.
The raw material batching station is provided with one limestone, sandstone, iron ore and aluminum bauxite warehouse. Warehouse bottom is set to feed the scale. Various raw materials are metered according to set ratio and then sent to raw material grinding mill by belt conveyor.
How to adjust the ratio of Various Raw Materials
The starting operation of various raw materials feedstock is interlocked with the raw material grinding motor and the lock air feeder. The feeding amount and ratio will be automatically set according to the chemical composition of each rate value, then load of the mill and analysis result of the raw material, after comprehensive calculation by computer (the raw material quality control system). And adjust the ratio at any time to ensure raw material composition and rate value of the milled raw material are homogenized to achieve quality requirements of kiln. The dust collection device is started before all devices are started, and all devices are shut down.
Cement plant can be set up with vertical mill system for drying and grinding raw materials. The three-fan system consisting of preheater fan, raw material fan and kiln exhaust fan makes the system operation control convenient and flexible, and easy to produce stably.
How to Filter out Metal Matter Damage
The mixed raw materials from batching station are fed into the raw material mill by a belt conveyor and a lock air feeder. In order to prevent metal matter pieces mixed in the raw material from entering the grinding machine, a permanent magnet self-unloading iron remover is arranged above the belt. A metal detector is placed in front of the grinding port. If it is detected that there is still metal matter mixed in the raw material, the pneumatic dispensing valve will automatically switch to the bypass and be discharged into the spare chamber. After main channel will be automatically restored to ensure the grinding and continuous feeding. When the grinding disc rotates, the material is continuously crushed by the roller on the grinding machine, and gradually spreads out to the peripheral wind ring under the action of the centrifugal force of the grinding disc, and then the high temperature exhaust gas from preheater is carried up, and dried at the same time.
Raw Material Grinding by Ball Mill or Vertical Mill
The raw material of qualified fineness screened by grinding machine is taken out of ball mill by airflow, and enters the kiln tail bag. After the gas is separated, the air is transported by the chute, the hoist, the air transport chute is sent to the homogenization store. The exhaust gas is extracted by the raw material grinding fan, and part of it is returned to the raw material grinding as circulating air to meet the requirements of drying and grinding. The remaining exhaust gas is discharged into the atmosphere through the raw material grinding fan and the chimney. The material discharged from vertical mill slag discharge port is returned to the vertical mill for re-grinding by means of a conveyor such as a belt conveyor and a hoist.
When the kiln mill is running at the same time, the exhaust gas from the preheater is sprayed with a small amount of water through the humidification tower to be cooled, and then sent to the raw material mill by a part of the preheater high temperature fan; the remaining exhaust gas is sent to the kiln tail bag dust collector. The temperature of the grinding gas can be controlled by the amount of water sprayed by the humidification tower according to the change of the integrated moisture of the raw material. When the kiln stops running, the preheater exhaust gas is cooled by the humidification tower to about 150 °C, and is sent directly to the kiln dust collector by preheater fan. After the purification, the exhaust gas is discharged into atmosphere by the exhaust fan. . The kiln dust received by the humidification tower and the raw material collected by the dust collector are sent to the hoisting hoist by the screw conveyor and the chain conveyor, and then sent to the homogenization warehouse; when the kiln is stopped, the dust can also be used. Raw material is directly transferred into the kiln via the electric gate and the kiln hoist.