Electromagnetic separation magnetic field types

Drum-type electromagnetic separators comprise a stationary set of magnets surrounded by a horizontally mounted rotating drum or cylinder made of a nonmagnetic material. The crushed material is passed over the drum, and any tramp iron contained in it remains clinging to the drum and is carried round to the underside thereof, where there is no magnetic field, so that the pieces of iron fall... 

In the magnetic separator, material is passed through the field of an electromagnet which causes the retention or retardation of the magnetic constituent. It is important that the material should be supplied as a thin sheet in order that all the particles are subjected to a field of the same intensity and so that the free movement of individual particles is not impeded. The two main types of equipment are ... 

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