The Crushing ratio of each Stone Crusher

Crushing ratio, is the total reduction from feed to products, is a factor that sets the need- ed number of crushing stages. Also, the rock type effiects on the reduction ratio, the harder the rock, the lower the reduction ratio in each crushing stage. In the other words, more stages are needed while crushing harder rock com- pared to softer rock. Typical reduction ratios (calculated between feed 80-% passing point and product 80-% passing point) in each crush- er type are listed in table below:

Crushing ratio effiect also on product shape. As the high reduction ratio in compressive type of crushers is made mainly by cleavage type of breakage, i.e. breakage between liners, it cannot produce good shape aggregates. Also, too rough impact type of breakage ruins the particle shape.

Instead of this, the attrition between particles is the key to make cubical or even spherical aggregates. However, reduction ratio with attrition type of breakage remains very low. With compressive type of crusher the reduction ratio, adjusted mainly by the feed fragmentation and crusher closed side setting has to be 1,5-2,5 to achieve best possible end product shape. Verti- cal shaft Impactors utilise mainly the attrition type of breakage. It means, that the reduction ratio is very small, but the shape of aggregate is excellent.