Tribo-Aero-Electrostatic Separator for Ternary Mixtures of Granular Plastics

This paper presents a comprehensive study of an electrostatic separation device for the recycling of granular plastic materials from waste electrical and electronic equipment (WEEE). The peculiarity of this system is the association of two charging techniques: 1) fluidized bed (dynamic charger) and 2) sliding on inclined plates (static charger)—and two superposed separation units, in order to achieve the selective sorting of a granular mixture composed of three different species of insulating materials. The tests were performed on a mixture of high-density polyethylene (HDPE), polyvinyl chloride (PVC), and polycarbonate (PC). A set of tribocharging experiments was conducted for each material, so that to choose the nature of the walls of the static charger. The analysis of the purity of separated products was performed using an image processing program written in MATLAB. High-purity separation (85%, 95%, and 75% for the PVC, PC, and HDPE products, respectively) was obtained at a recovery rate beyond 80%.