15000 HP gearless ball mill drive in cement-why not!

Over recent years, there has been a clear trend towards higher capacity cement production units. Five to ten years ago, 2500 tonnes per day was large. Nowadays in Asia, lines are built for 10000 tonnes per day. The development of ball mill grinding units has not shown the same trend, output and ratings have remained more or less constant perhaps due to the success of pregrinding with high pressure grinding roll technology. This lack of movement towards larger mills is somewhat surprising since in the same period the drive rating of ball mills for similar duties such as ore grinding has shown an increase in drive ratings from 3000 to 15000 HP. Ball mills in this power range are equally, when not more, efficient than their smaller counterparts and are capable of processing the total daily production within the overnight low tariff period for electrical energy. Significant energy and cost economies can be achieved with a gearless mill drive working with a ball mill in these upper power ranges. This prospect should also be of interest to the cement industry. The technology is available for an up-sizing of cement grinding installations and the gearless mill drive is a proven, reliable drive