Corona-Charged Insulating Belt Electrode Conveyor-Type Electrostatic Separator for Granular Plastic Wastes

A new configuration of triboelectrostatic separator equipped with an insulating belt conveyor electrode is described and analyzed in this article. The insulating belt is continuously charged by the corona discharge produced by a fine-wire electrode, placed at a distance of 5 mm above it. The charge accumulated on the belt leads to the enhancement of the electric field in the active zone of the electrostatic separator. Two types of materials, namely polyvinyl chloride and polyester (PET), were used for the conveyor belt and their performances in terms of electrostatic separation efficiency were compared. Corona charging the belts improved both the recovery rate and the purity of the separated products. Better performances were obtained when using the PET belt conveyor electrode, where more than 95% of the polypropylene particles and 87% of the polystyrene particles were recovered as 97% and 92% pure products, respectively.