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Kind Introduction To Different Types Of Crushers

Crushing is the first step of mineral processing where the ore/rocks from the mine site is fed to mechanical equipment in order to reduce the size for subsequent stages and thus liberate the valuable mineral from the gangue.Mostly this stage is dry and can be performed in various stages (2-4).The crushers are used to reduce the size of the rom ore (as large as 1.5m) to a size that can be fed to ball grinder(as small s 4-6mm).Depending upon the requirement there could be a primary, secondary, tertiary and quaternary stage.In most of the operations primary stage is performed at the mine site (surface or underground).Primary crushing machines are commonly designed to operate 75% of the available time, mainly because of interruptions caused by insufficient crusher feed and by mechanical delays in the crusher.Different types of breakers can be operated in open circuit or in closed circuit, and mostly secondary and tertiary crushers are operated in closed circuit.Primary breakers are heavy duty machines used to reduce the size of rom ore to a size manageable by secondary crushers or ag/sag mills.They always operated in open circuit.Jaw and gyratory crushers are two most important types of primary breakers but sometimes impact type crushers are also used if the ore is soft.The jaw type crusher reduces the size by the compression force when the rock is pressed against the two plates.It consists of a set of vertical jaws, one jaw fixed and the other moved back and forth relative to it by a cam or pitman mechanism mounted such that the stationary jaw provide the breaking surface and the moving jaw exert the compressive force.The rock remains in the jaws until it is small enough to pass through the gap at the bottom of the jaws.The speed of jaw type crushers varies inversely with the size, and usually lies in the range of 100-350rev/min.The main criterion in determining the optimum speed is that particles must be given sufficient time to move down the crusher throat into a new position before being nipped again.The jaws are usually constructed from cast steel and are fitted with replaceable liners, made from manganese steel, or "ni-hard", a ni-cr alloyed cast iron.All jaw type crushers are rated according to their receiving areas, i.E.The width of the plates and the gape, which is the distance between the jaws at the feed opening.For example, an 1830x1220mm crusher has a width of 1830 mm and a gape of 1220 mm.A hammer mill crushes material that is friable, by impacting it against a rotating hammer.Then the material is forced against a rugged solid plate called a "breaker plate" which further degrades the particle size.Finally, the material is forced over a discharge grate by the hammers, where crushed finer particles drop through the discharge grate and larger particles travel around for another crushing cycle, until they fall through the discharge grid.There is many other different kind of crushers developed depending upon the ore characteristics and energy requirements such as gyradisc and rhodax crushers (special form of cone crushers), rotary impact crusher, tidco barmac crusher, reversible hammer mill etc.Key variables for a crusher is its open and closed side settings, operating gap for roll crushers, particle nipping angle, resident time for a particle in the crushing chamber and feed size of the particle.Stone crushing plant:http://www.Hxjqchina.Com/n26.Html sand washing plant:http://www.Hxjqchina.Com/product-list_29.Html.

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