Crushers are on the move.

Versatility and flexibility in application are the major trump cards that mobile crushers play in comparison to stationary crushing plants. What are mobile crushers used for? What are the differences between the various crushing techniques? What about the hardness of the rock to be processed?

Mobile crushers are used in quarries, in mining, on job sites, and in the recycling industry. The robust plants mounted on crawler tracks are capable of processing both rock and recycling material, producing mineral aggregate and recycled building materials respectively for the construction industry. When processing natural stone or recycling material like demolition waste, concrete, asphalt, incineration ash or steel slag, an excavator or wheel loader feeds the material into the mobile crusher. The then produced material is used for road construction or other, similar applications.

Flexible relocation

A major advantage of mobile crushers is their flexibility in terms of moving from one location to the next. They are suitable for transport, but can also cover short distances within the boundaries of their operating site, whether in a quarry or on the job site, on their own crawler tracks. When operating in quarries, they usually follow the quarry face, processing the stone directly on site.

Short setup times

Mobile crushers are loaded on low-loaders when transported over longer distances to a new location. No more than 20 minutes to 1 hour is needed for setting the plant up for operation. Their tremendous flexibility enables the mobile crushers to process even small quantities of material with economic efficiency.

Different crushing techniques

Crushing techniques distinguish between pressure crushing and impact crushing. Jaw crushers or cone crushers use the so-called pressure crushing technique where material is reduced in size mainly by high pressure between slow-moving wear parts. Impact crushers use the so-called impact crushing technique, in which the rock is accelerated by a massive fast-moving rotor and reduced in size by impacting against breaker walls.

Depending on material hardness

Jaw crushers are widely used for crushing medium-hard to hard rock, and are mostly used as primary crushers. Impact crushers work as both primary and secondary crushers for processing soft to medium-hard rock, producing larger quantities of fines. Cone crushers are used predominantly as secondary crushers for hard rock.

Mobile screening technology and grain size

Mobile plants allow the combination of pre-screening, which prepares the rock for the crushing process, and grading, which precisely separates defined grain sizes into different end products, to be integrated with the crushing unit into one single machine. In the first stage, the material is screened using an active pre-screen. After pre-screening, it is transferred to the crusher, from where it is either stockpiled via a discharge conveyor or forwarded to a final screen or a secondary crushing stage. Depending on the specified end product, the grains are then either graded by screening units or transported to additional crushing stages by secondary or tertiary impact crushers or cone crushers, if required. Further, downstream screening units are used for grading the final aggregate fractions.

Combining different types of plants

The process of pre-screening, crushing and grading described above is a common operation in mobile materials processing, and can be varied in a number of ways. Mobile crushers with up to three crushing stages are increasingly used in modern quarries today. Different mobile crushing and screening plants can be combined for managing more complex crushing and screening jobs that would previously have required a stationary crushing and screening plant.