A very general questions and I guess a general answer

Assuming that all systems are in closed circuit with a 3rd generation dynamic separator.

Ball mills are common, simple but consume a bit of power due to the ball charge. Can get high rates, over 200tph. Drive arrangement to suit when getting high motor powers.

VRMs - vertical roller mills - seem to be the norm these days. Lower kWhr/tonne power consumption, lower foundation footprint.

The particle size shape from balls mills are rounded and VRM are angular. This app. means a diff. water demand in concrete.

It is possible to get the same PSD slope with either mills

Hence, from a customer viewpoint, cement from ball and VRM may be seen as different. Hence, some people expand capaicty with the same mills as existing eg usually old ball mills with new ball mills.

Roll presses are not often used as the prime grinding device. They have the lowest power consumtion. They are usually used as pre grindings for clinker in front of ball mills. An increase in ball mill capacity will result. Hence, they are usually employed where a small capaicty increase in the ball mill is desired. They are not usually installed with ball mills in new installations - more gear, more issues. Roll presses require more attention and care and good design/arrangement than simple ball mills.

They are other factors eg clinker temperature, gypsum quality, desired product specifications/quality etc etc that must be considered when making a configuration selection.

There is always more to it than meets the eye.

Cheers

James ■

Nicky

This is the way that we see it.

Roll presses are only recc. where a small capacity (<30%) increase is required over a ball mill.

Some people look at them for power savings but this is not the only considerations.

Others may have diff. opinions

Cheers

James ■