Eddy current separation can be used in separation of non-ferrous particles from crushed waste printed circuit boards

Waste printed circuit boards are produced greatly due to the wide application of electronic devices, in which non-ferrous metals are valuable resources. Without effective recovery processes, it can cause serious heavy metal pollution. Traditional recover technologies will cost too much energy, materials, manpower together with producing secondary ecological and environmental pollution. Eddy current separation is a green and low-cost technology to separate non-ferrous metals from others. However, it was well reported that there was a certain particle size limitation for the separated non-ferrous metals. Was it a truth or unbreakable principle for eddy current separation? In this paper, we researched the causes of the size limitation for eddy current separation. Meanwhile, the eddy current separation mechanism was detailed explained in a new comprehension related to the change of magnetic flux density, generation of eddy current force and particles' motor behaviors. We consider that there is no size limitation for the separated non-ferrous metals in eddy current separation as long as the size of magnetic pole is enough big or small. This paper brings a new recognition about the traditional eddy current separation and will expand new application area for this environment-friendly and low-cost technology.