I am making studies for cement plant and would like to make a following question? Is possible to control the weight in the ball mill (cement or raw mill plus balls) in order to save energy? My view point is if you have any chamber unbalanced in ball mill, the motor drive can be working in a forced way and spent much more energy than the necessary? Is possible to use the balls to correct that balance, because today we have in the cement plant a different weight in each chamber?

The weight of grinding balls in the mill and the power drawn by the mill main motor are directly proportional to one another. Therefore it is possible to reduce the power drawn by the mill by reducing the ball charge. However, this will then result in the output of the mill falling due to less grinding balls being present to grind the clinker and generate surface area. As with all these things there is an optimum ball charge and output which corresponds to the lowest unit energy consumption.

In order to optimise the performance of a ball mill, is there any suggested air velocity through the mill that we should use? Our cement plant has some very old ball mills. One in particular is a 4.572m x 13.9m two compartment mill, closed-circuit, with a Sepax separator 2S-375 separator. The separator and mill are vented by the same dust collector. We are currently running a high mill outlet ventilation on the mill, greater than -4" W.C. What is an acceptable mill ventilation static pressure range for this type mill circuit?

1.5 to 2 m/s air velocity through the mill is normal for a closed circuit mill.