Separation of small metallic nonferrous particles in low concentration from mineral wastes using dielectrophoresis

This paper presents a theoretical study and a method regarding the separation of small nonferrous particles (Au, Ag) in low concentration from mineral wastes, using the dielectrophoresis phenomenon. The main theoretical considerations referring to the dielectrophoresis and the appearance and action of the electric gradient forces, typical for nonuniform fields, are presented. The gradient and superficial electric forces, in competition with gravitational forces, act on the dielectric particles from the surface of the material subjected to the separation process. Under the combined actions of all these forces, the metallic particles are concentrated on the surface of the mixture, forming a superficial conductive layer. Finally, the experimental results and conclusions regarding the concentrations in Au and Ag of the particles collected from the formed layer are presented, based on chemical analysis.