Vertical Roller Mills or Ball Mills for Cement Finish Grinding?
Vertical roller mills (VRM) and ball mills have absolutely different technologies. However, if you adjust the operation parameter of VSMs rightly, this two type grinding mills are able to meet customer’ requirements with almost the same cement performance. Even so, this two type grinding mills have their own advantages.
VSM is integrated grinding, classification and drying into one unit, which is superior to ball mill. However, the VRM is a more complex piece of equipment with a sophisticated hydraulics system that operates the rollers, the changes of feed quality and quantity have influence on grinding process which is sensitive than ball mill. By contrast, operation of a ball mill is relatively simple, with no moving mechanical parts within the mill itself. The system is tolerant to variations in both mill feed quality and quantity.
VSM is superior to ball mill on energy consumption, except for this, other factors also have influence on investment cost, such as cost of grinding aid, fuel used in hot blast stove and cooling water( although its impact is small). Maintenance cost of this two type mill is almost same, so it makes no sense to contrast the two mill evaluation.
Compared with ball mill, the equipment costs of VRMs are higher , reflecting the greater complexity of the system, which includes items such as the rollers, table and the hydraulic system. Overall, when equipment, erection and civil costs are taken into account, the cost of a VRM project is around 20 – 25% greater than a ball mill system of the same capacity.
Obviously, there are a lot of factors should be taken into account when choose VSM system and ball mill system in cement grinding, although expense of electricity and whole equipment is important for that. These factors have great difference due to different installation site, so we cannot make an applicability rank for this two type grinding mills, it should be determined by local conditions and specific requirements.