Crusher
Crushers are machines for crushing lumpy feed material to smaller grain sizes in coarse to medium size range. Mostly they are used for the production of minerals from broken stones, but are also in the food industry to be found for example in the rendering.
In contrast, one speaks of mills, if the target grain size in the fine or fineness range should be. Usually this limit is seen at a target grain size in the range of 1 mm to 10 mm. The most extensive deployment of crusher in the industrial processing of mineral raw materials, see quarry, lime works, gravel plant, mining as well as secondary materials, see recycling, construction waste. Breakers can both stationary and mobile are used (on wheels or on caterpillar tracks ).
Previously stationary systems were the only solution for the treatment applicable construction waste. The mid- 1990s, mobile recycling has developed compact installations and is now the world on the rise. Mobile crusher can not move only on the site, but are generally mobile. They can be brought to the place of treatment due to the relatively low transport weight, to recycle the material there directly. Conversely, all of the material from the site for inpatient treatment plant needs to be transported, which is associated with transport costs and causes increased truck traffic.
Objectives of crushing
- Reduction of the upper grain sizes
- Changes in the particle size distribution
- Change in grain shape
- Selectively digesting Connected to achieve a separation and exposure of the individual components
Crushing principles
Breakers can be classified according to the predominant crushing principle.
Pressure comminution
The comminution energy acts with great power and with low speed to the material to be processed.
Designs:
- Jaw Crusher
- Cone crusher, gyratory crusher and cone or
- Roll crusher
Impact crushing
The material to be comminuted exceeds a high energy to a work surface. At impact crushers horizontal shaft which energy is introduced (rotor with beater bars ) in the work area, which then acts on the inflowing rock, and impact crushers, vertical shaft, the material is accelerated by centrifugal force inside a rotor to be targeted outside against a fixed work surface to be performed.
Designs:
- Impact crushers horizontal shaft
- Impact crusher vertical shaft, and rotor crusher
Impact comminution
The working surface is accelerated and against the material to be shredded, which is ideally located in front of a solid ground out.
Designs:
- Hammer Crusher
Shear / friction
The material to be comminuted is located between two lines of work ( shear) or working surfaces ( friction) that exert pressure and are moved simultaneously in opposite directions.
Designs:
- Shredder for shear
- Ball mill for friction
Areas of application
- Production of sand, gravel, grit and gravel quarries and gravel pits
- Processing of ores, salts, coal, minerals in mines
- Coal preparation in the power plant
- Separation of solid materials in the chemical and pharmaceutical industry
- Preparation of cement
- Food industry
- Recycling industry
- Treatment of recycled building materials, such as concrete recycling
Assessment of crushers
Main criterion for the evaluation of crushers is the crushing effect. Since each breaker inevitably not only provides a single desired particle size but always a range of sizes, it is assumed to assess the comparison of the particle size distribution in the feed compared to the grain size distribution in the final product. These distribution curves are called grading curves.
Typical degrees of comminution in mineral processing:
In addition to the crushing effect yet another breaking effects can be important, such as cubic particle shape, angularity, hardness, selectivity of the reduction. Other important aspects are throughput, input costs (especially for wear and energy consumption ), capital expenditure and maintenance.