What is the Optimal Feed Size for an Eddy Current Separator?

In the field of non-ferrous metal recycling, eddy current separators play a pivotal role. As metal-bearing materials pass over a high-speed rotating magnetic drum, eddy currents are induced within the non-ferrous metals; this process enables the recovery of high-value non-ferrous metals—such as copper, aluminum, zinc, and magnesium—from waste streams.

The operating principle of an eddy current separator involves inducing a magnetic field within conductive metals (such as copper and aluminum), thereby generating a repulsive force that “flings” the metals off the conveyor belt. For high-capacity industrial production lines, the most economically efficient feed size typically falls within the range of 20 mm to 50 mm.

Within this range, the material can be spread evenly across the conveyor belt in a “single layer.” At this scale, the ratio of magnetic repulsion force to object weight is optimized for maximum efficiency, often resulting in separation purity levels of 98% or higher.

Suny Group’s heavy-duty eddy current separators are also capable of processing fragments up to 150 mm in size; however, this requires specific configurations—such as larger-diameter rotors and reduced belt speeds. To maximize return on investment, Suny Group strongly recommends pre-screening the material using a trommel screen to ensure that the eddy current separator achieves high-purity separation results.