In the crushing process, in order to avoid collapse and reduce costs, the principle of “more crushing and less grinding” should be possible.
In ore dressing plants, two-stage or three-stage crushing is generally used. According to the different particle size of the crushed product, it can be roughly divided into three stages: coarse crushing, medium crushing and fine crushing.
Coarse crushing: the feed size is 1500～500mm, crushed to 400～125mm; Such as: jaw crusher, hammer crusher
Medium crushing: the feed size is 400～125mm, crushed to 100～50mm; Such as: impact crusher, spring Cone crusher, hydraulic cone crusher
Fine crushing: The feed size is 100-50mm, and crushed to 25-5mm. Such as: cone crusher single cylinder cone crusher etc.
Other Sand making: The feed size 40-10mm, and crushed to less 5mm. Such as: sand making machine, double roll crusher, composite crusher.
Crushing and grinding are preparatory operations before selection. The prerequisite for beneficiation is to separate the useful minerals in the ore into monomers. Since the particle size of useful minerals as monomers is very small, sometimes it is necessary to grind the ore to a fineness of less than 0.074 mm, which accounts for 80%, or even finer, in order to achieve monomer separation of a certain useful mineral.
The size of the ore coming out of the stope is very large. For example, the size of the ore supply in the open-pit mining can be as large as about 1000 mm. Therefore, the ore blocks as large as 1000 mm must be crushed to only a few tens of microns (1 micron = 1/1000). Millimeters) are often completed in several stages.
In terms of crushing, large-scale concentrators generally use coarse, medium and fine three-stage crushing (four-stage crushing is also used) to gradually reduce the size of the lump ore to about 8-mm, and then send it to the grinding machine for grinding. Until the useful mineral particles can achieve monomer separation.