Assume that iron dust is mixed with non magnetic dust or powder and it requires separation. How would the iron dust behave if the material containing the iron dust is allowed to fall through a magnetic field zone created by placing electromagnets in an array so that the magnetic zone is about 600 mm wide (across the flow), 100 mm thick (flow thickness) and 1000 mm deep (along the flow). While free falling through this zone the iron particles should get attracted to the electromagnet poles. The free fall would allow the iron dust particles to move freely towards the poles. Do you think that this will happen? What do think should be the strength of the magnetic field? Would the iron behave as if it is in any other force field, say, like gravity, where it would get attracted to the nearest mass?