Eddy-Current Separation by Permanent Magnets. I. Theory

In eddy-current separation, forces are exerted on non-ferrous metal particles to separate these metals from solid material mixtures. These forces depend on the magnetic field inducing the eddy currents as well as on the electric conductivity and the shapes and sizes of the particles. The present paper provides model calculations of the forces exerted in a vertical eddy-current separator. A quality factor was developed by which the magnetic configuration of these systems can be optimized. The quality factor was also used to design rotating disc separators. In both separation systems the magnetic fields are produced by permanent magnets. The validity of the model calculations was tested by measurement of the exerted forces. 7 ref.