The crushing of materials is an indispensable process in many industries, such as metallurgy, mining, building materials, chemical industry, ceramics, etc. the choice of the crusher machine should be analyzed in detail of the material properties and crusher structure and performance. In the mining process, crushing mainly divides into coarse crushing, medium crushing, and fine crushing, crusher machine have various type and model accordingly. The used most stone crushers have jaw crusher, cone crusher, vertical shaft impact crusher (also known as sand making machine), impact crusher, hammer crusher, and so on.
Five crushing mechanisms
Crushing is the process of changing a large piece of material into a small piece. in this process, an external force( human, mechanical, electrical, chemical, atomic, etc) is applied to the crushed material. when the external force exceeds the strength limit of the crushed material, the large piece of material is crushed into small pieces. ore is a kind of brittle, material that is crushed at deformation force.
- Attrition crushing/ squeeze crushing: the material crushed by the increasing pressure between the two working plate.
- Crackling: the crusher machine cavity equipped with sharp edge rods that generate powerful separation force.V
- Fracture crushing: fracture the large material into small pieces by bending force.
- Grinding: there is relative motion between the ore material and the moving warking plate, ore material under the compress and cutting force.
- Impact crushing: the material is crushed by the impact force, this crushing mode has features like high efficiency, high crushing ratio and low consumption.
|Jaw crusher||Low cost, simple structure, strong applicability, convenient maintenance.||Discontinuous crushing, low crushing ratio|
|Cone crusher||High crushing ratio, uniform particle, low consumption. Capable of medium – fine crushing.||High purchasing cost, complex structure, with inconvenient maintenance.|
|Vertical shaft impact crusher||The fine crushing task, small and uniform shape.|
high efficiency, low energy consumption.
|Impact crusher||High capacity, low consumption. Good particle shape.||Liner steel easy to wear, dust.|
|Hammer crusher||Simple structure, easy operating, lightweight.||Hammerhead easy to wear|
In fact, any kind of crusher and mill can not be broken only by one of the methods listed above, usually by two or more methods combined to break. Such as compress crushing and fracture breaking, impact and grinding.
What factors should be considered to select the crusher?
- Type and hardness of the material
The kind and hardness of materials is an important principle in choosing crusher. the hardness is varied with different ore material. The MOHS hardness is usually used to indicate the hardness of materials. There are 10 grades of Mohs hardness. The harder the ore, the more difficult it is to break, and vice versa.
- Moisture content
The moisture is a nonnegligible factor. When the moisture content is too high, the fine material will agglomerate or stick to the coarse material, thus increasing the viscosity of the material, reducing the speed of ore discharge and decreasing the productivity. Serious, it may even cause the blockage of ore discharge, affecting the normal production.
- Feeding and discharging size
if the content of coarse grain(bigger than the discharging size) in the material is high or the ratio of the largest piece to the width of the feed ore is high, the crushing ratio will be high, thus decrease the productivity. when the content of the fine grain is high, the crushing ratio will be small, thus increase productivity.
The common understanding is that the higher the output requirement is, the larger the size of the crushing equipment is, and the corresponding input and output will increase.
The operating site, site space.