Electromagnetic concentrator is made according to the principle that magnet is attractive to iron ore.

It can be seen from the figure that when the electromagnetic concentrator works, the iron sand will fall into box B.

In the process of ore falling, when passing through electromagnet, non iron ore cannot be attracted by electromagnet and directly falls into box a due to gravity;

The iron ore can be attracted by the electromagnet, adsorbed on the drum and rotated with the drum. When it reaches the top of Box B, the electromagnet's attraction to the ore is very small, so the ore falls into Box B due to the effect of gravity.