Cement mill works in the key part of cement manufacturing plants. Grinding systems are either ‘open circuit’ or ‘closed circuit’. In an open circuit system, the feed rate of incoming clinker is adjusted to achieve the desired fineness of the product. In a closed circuit system, coarse particles are separated from the finer product and returned for further grinding.
cement ball mill vs. vertical mill
The grinding process in ball mills and vertical roller mills differ fundamentally. In a ball mill the comminution takes place by impact and attrition. The comminution in the vertical roller mill takes place by exposing a bed of material to a pressure sufficiently high to cause fracture of the individual particles in the bed, although the majority of the particles in the bed are considerably smaller than the thickness of the bed.
It is thus necessary that a stable and consistent grinding bed is formed between the rollers and the table of the vertical roller mill, able to sustain such a pressure without the material being squeezed away from the pressure zone. A stable grinding bed is usually easily obtained in raw material grinding in a vertical roller mill with a high efficiency separator. However, in cement grinding it becomes more difficult to form a stable grinding bed as:
cement is ground much finer than raw materials
the feed to a cement mill is often completely dry and is significantly more difficult to grind than raw materials
requirements to the particle size distribution of the finished product are much more strict when grinding cement than when grinding raw materials
cement crushing and machines
There are many crushers used in crushing these raw materials, such as jaw crusher, impact crusher, cone crusher and vertical shaft impact crusher, etc. According to the raw materials’ different particles and hardness, there are several suitable crushers which can be used in the crushing.