We present a novel design of an eddy current separator for the extraction of non-ferrous metal particles (e.g. aluminum, copper, silver, gold) from nonmetals.
Our setup is optimized for the separation of sub-1-mm particles, far below the limit of conventional conveyor belt technologies.
Graz University of Technology
Research & Technology House
Mandellstraße 9/II, 8010 Graz, Austria
Patented (AT518730B1)
Similar to known setups, also in our setup eddy currents are induced in conductive material through one or more rotating cylinders containing very strong permanent magnets (yet in a highly specific orientation inspired by particle accelerator designs).
However, contrary to conventional technologies, the material stream is oriented in parallel to the rotational axis of the magnet drum, and is fed with material from the top, exploiting gravity. This parallel arrangement also enables almost unlimited scalability by adding any desired number of rotating magnet discs - a decisive advantage of our design.
Multiple channels run along the outside of the cylinder, and whenever the flow of material passes a rotating disc of magnets, conductive material will feel a force which makes it swap from the feeding channel to a neighboring channel.
Eventually, all feeding channels are collected to give the total nonmetal fraction, while all neighboring channels, only reached by material affected by the rotating drums, are collected into the total non-ferrous metal fraction.
The capabilities of our technology can be significantly enhanced if the whole separation process takes place in a liquid, e.g. water. The prototype shown in the picture below resembles such a water-based implentation:
