Vertical Roller Mills vs Conventional Ball Mills

The Vertical Roller Mills are successfully used for very fine grinding. This equipment is very advantageous in comparison with ball mills. The power consumption of vertical mills is about 35% to 40% lower than ball mills and the media grinding consumption is significantly lower too. It has patented new vertical milling technology that combines low energy input with maximum grinding force to accurately control the specification of fine powder output. Throughput capacities can also be controlled by both the size of the grinding chamber and a modular approach that enables multiple grinding systems to be incorporated in special twin mill configurations. The system is now being taken up in a range of material and mineral processing operations.

In wet grinding, we should differentiate between stirred media grinding, which can be both vertical and horizontal, and tumbling mills with manufactured grinding bodies. A continuous grate-discharge tumbling mill with grinding balls does seldom have ball size below 20 mm since you then will have unacceptable media losses or problem with grate throughput. To get energy efficient grinding below approx. 40 µm you need to have finer grinding balls than are suitable for the tumbling mill. So, the case for the stirred media mill that often have media in the range 5-10 mm if used as a tertiary grinding step or for re-grinding.