A vertical raw mill is a type of industrial equipment used to crush or grind materials into small particles. It is widely used in the cement industry and other manufacturing sectors for raw material preparation. The working principle of a vertical raw material mill can be understood by examining its key components and the process that occurs inside the mill.
Components of a Vertical Raw Material Mill:
Grinding Table: The grinding table is a flat, circular surface located at the bottom of the mill. It supports the weight of the materials to be ground and transmits the grinding forces to the mill’s foundation.
Grinding Rollers: The mill has several rollers that rotate on the grinding table. These rollers apply pressure to the materials, crushing them against the grinding table and grinding them to the desired fineness.
Separator: The separator is a crucial component that separates the ground material from the airflow and sends the fine particles to the collection system while returning the coarse particles for further grinding.
Mill Housing: The mill housing encloses the grinding table and rollers, protecting them from external elements and maintaining the necessary operating conditions inside the mill.
Feeding System: Raw materials are fed into the mill through a feed pipe, either directly or through a conveyor system. Proper and controlled feeding is essential to achieve optimal grinding efficiency and prevent blockages.
Grinding Process:
The grinding process in a vertical raw material mill involves the following stages:
Material Entry: The raw materials, such as limestone, clay, shale, silica, etc., are fed into the mill from the top or side of the housing. The materials are then crushed and ground between the rollers and the grinding table.
Grinding and Compression: As the grinding rollers rotate on the grinding table, they exert pressure on the material, crushing it and grinding it into fine particles. The applied pressure is sufficient to overcome the material’s resistance and comminute it to the desired size.
Drying: Some vertical raw mills are equipped with a hot gas inlet, which helps to dry the raw materials during the grinding process. This additional step ensures that the materials’ moisture content is reduced, enhancing the overall efficiency of the grinding process.
Classification: After the grinding process, the fine particles are carried out of the mill by the airflow generated by the separator. The coarse particles, on the other hand, fall back onto the grinding table for further grinding.
Collection: The fine particles are collected using a cyclone or bag filter system, while the air is cleaned and recirculated through the mill to reduce energy consumption.
Advantages of a Vertical Raw Material Mill:
High Grinding Efficiency: The vertical arrangement of grinding elements allows for efficient grinding and high material throughput, leading to reduced energy consumption.
Low Maintenance: Vertical mills have a simple design with fewer moving parts, resulting in lower maintenance requirements compared to horizontal mills.
Flexibility: Vertical raw mills can handle a wide range of materials, including moist and abrasive substances, making them suitable for diverse industries.
Space Saving: Vertical mills have a smaller footprint compared to horizontal mills, allowing for more efficient use of available space in the production facility.