How Do Recycling Machines Sort Cans So Fast? An eddy current separator is a device that uses magnetic forces to separate non-magnetic but conductive metals, like aluminum, from other materials, such as plastic. When mixed waste moves along a conveyor belt and passes through a rapidly rotating magnetic drum, the changing magnetic field induces swirling currents (called eddy currents) in the conductive metals. These eddy currents create their own magnetic fields that oppose the original field, gen