Factors Influencing the Triboelectric Charging of Granular Plastics in a Rotating-cylinder-type Tribocharger

The electric charging of granular plastics in view of their electrostatic separation is one of the major industrial applications of the triboelectric phenomenon. The granules get charged by collisions and frictions with each-others and with the walls of the tribocharging device. In electrostatic separation applications, the granules of a mixture must be sufficiently charged to be attracted by electrodes of opposite polarity for their separation by type of material. The objective of the present work is to study the effects of three factors that influence the triboelectric charging of polycarbonate granules (size: 2 mm to 5 mm) originating from waste electric and electronic equipment in a rotating-cylinder-type device: particle residence time, cylinder inclination and its rotation speed. The performance of the triboelectric charger was evaluated by measuring the charge per mass ratio of the granules collected at the outlet of the device.