Three Stage Crushing Plant

Most plants consist of more than one crushing stage. Three crushing stages with different objectives can be defined:

Aggregate Crushing Plant

Primary Stage

In this stage the material is prepared for further processing. The machine which performs the functi on of the primary crusher is very often the only crusher at a plant. The term primary crusher denotes the reduction machine which continues the process that blasting has left off. Product from the primary crushing stage should be as homogeneous as possible with a maximum size of about 150 mm and a minimum amount of fines. In hard rock quarries two crushing stages are usually required to achieve this result. One crusher if the rock is of a softer nature. Once material has passed through the primary stage it is of a suitable size to be moved by conveyor.

Secondary Stage

This term applies to the crushing stage which follows immediately after the primary stage; it can consist of either a single or multiple crushers. The feed is all or part of the product of the primary crushing stage. The choice of machine will depend largely on the nature of the feed. Where it is necessary to control the size of the product closed circuit crushing is employed.

Tertiary Stage

If a fine particle size product is required a further reduction in size of material may be needed. To achieve this; a tertiary crushing unit would be installed to produce a good quality, regular size sand.