Electrostatic Separation of Metals and Plastics From Waste Electrical and Electronic Equipment

Abstract Most separation techniques for waste electrical and electronic equipment (WEEE) require preliminary scrap-granulating operations to carry out mechanical component dissociation. Electrostatic separation is the selective sorting of electrically charged or electrically polarized granular WEEE under the action of the electric field forces. This chapter will give an overview of the principles of operation and the industrial applications of the three “standard” classes of electrostatic separators: (1) plate type, based on electrostatic induction charging of conductive particles; (2) roll type, which takes advantage of corona discharge as a charging mechanism for nonconductive particles; and (3) free-fall type, employing the triboelectric effect to differentiate charging of insulating materials. Particular attention will be paid to the presentation of recent developments regarding the use of tribo-aero-electrostatic techniques for the processing of mm-size granular plastics mixtures, as well as to the description of two classes of electrostatic devices designed for the separation of submillimeter-size (micronized) WEEE.