Size reduction process

Minerals being crystals have a tendency to break into endless numbers of sizes and shapes every time they are introduced to energy. The difficulty in size reduction lays in the art of limiting the number of over and under sizes produced during the reduction.

Feed Material

If this is not controlled, the mineral will follow its natural crystal behaviour, normally ending up in over-representation of fines.

So, the trick when producing quality products from rock or minerals (fillers excepted) is to keep the size reduction curves as steep as possible. Normally that is what we get paid for - the shorter or narrower fraction - the more value!

To achieve that goal we need to select the correct equipment out of the repertoire for size reduction in a proper way.

They are all different when it comes to reduction technique, reduction ratio, feed size etc. and have to be combined in the optimum way to reach or come close to the requested size interval for the end product.

Feed material

All operations in size reduction, both crushing and grinding are of course determined by the feed characteristics of the minerals (rock/ore) moving into the circuit. The key parameters we need are the "crushability or grindability", also called work index and the "wear profile", called abrasion index.

Reduction ratio

Crushing Rock

As seen above all size reduction operations are performed in stages. All equipment involved, crushers or grinding mills have different relation between feed and discharge sizes. This is called reduction ratio.

The art of crushing

Crushing means different things for different operations and the production goals are not always equal.