Hi rodsallick,

Looks like we don't have any crusher salesmen on this forum.

One way to approach the problem is to talk to the technical representatives of suppliers of crushing equipment. Draft up a basic crusher quotation, and ask for a quote with recommended equipment. Then you can compare the motor sizes for the two types.

If you want actual running amps for the two alternatives under operating conditions, I would say that would only be available with a pilot plant - and that means big bucks.

We do have some crushing and screening engineers on this forum, but none who choose to share their words of wisdom on your question.

Regards - John.rz ■

The comparison between a vertical mill and a tube mill is a little bit more complex and must not consider only the speciffic power consumption.

For energy savings sometimes is quite necessary to analyse the complete grinding department. Of course a vertical mill have a reduce energy consumption for grinding, but the mill fan require a very big motor (the pressure drop in the vertical mill system is 900-1100 mm WG).

Also the abrasivity of the raw materials is very important (is easy to complete the grinding media charge of a tube mill compare to complete the wear lining of the grinding roller.

The vertical mill has better efficiency for grinding wet materials with a higher grain size imput. For fine particles at inlet strong vibrations can apear that usual request water injection in order to aglomerate the fine particles.

So, the comparison can be extended a lot. A real comparison can be done only having some inputs from equipment suppliers based on the specific process. ■

It is generally agreed that a vertical mill requires less than 1/2 the power of a ball mill to grind from 3" to less than 32 micron. ■

A crusher is not typically considered the correct technology when achieving the fineness targets you mention. ■