There are several types of rock crushers, each designed to perform specific tasks. Jaw crushers are commonly used for primary crushing, while gyratory crushers are preferred for larger rocks. Impact crushers are ideal for crushing medium-hard materials such as limestone, and cone crushers are often used for fine crushing.
Rock crushing is a multi-stage process that involves crushing the rock into progressively smaller sizes. Primary crushing is the first stage, often using a jaw or gyratory crusher. Secondary crushing involves further reducing the size by using cone or impact crushers. Tertiary crushing is typically the final stage, where products can be reduced to a fine powder.
Coarse crushing typically involves crushing operations that discharge at sizes 4- to 6-in. or coarser. Intermediate crushing involves operations taking feeds 6- or 8-in. maximum and making products down to -1/2 or 3/8. Fine crushing involves reduction by crushing to 1/4 or finer, but the distinctions between these stages are not always sharp.
Rock crushing is a mechanical operation that involves applying a sufficient force to relatively brittle solid particles in such directions that failure of the bonding forces in the particles is brought about. Crushing machines must be designed to exert either pushes or pulls on individual particles, as there are no other kinds of mechanical forces. The solid particles must be introduced into and maintained in the force zone so that the forces available can be applied to them.
The mechanics of materials is an important aspect of rock crushing. However, the use of specific brand names must be avoided in writing about mechanistic details. For example, impact mill rock crushers use a rotor and hammers to crush the rock, and the size reduction is achieved by impact of the hammers on the particles.
In conclusion, rock crushing is a necessary process in many industries, and there are several types of rock crushers available to suit different needs. Whether it is primary, secondary, tertiary, or fine crushing, choosing the appropriate crusher is important to achieve the desired product size and quality.