Experimental modeling of the tribo-aero-electrostatic separation of mixed granular plastics

Abstract

A tribo-aero-electrostatic separator can be successfully employed for the selective sorting of granular mixtures of polymers. The tribocharging of the material to be separated occurs in a parallelepiped fluidized bed. Two opposite walls of this device consist of metallic plates connected to two DC high-voltage supplies of opposite polarities, so that the charged granules are attracted to these electrodes and separated while still in fluidized state. The granules are then collected in two recipients each placed in a Faraday pail, to allow the instantaneous measurement of the mass and charge of the separated products. The experiments were carried out on binary mixtures of virgin polyamide and polycarbonate granules both in intermittent and continuous regime Real-time data-acquisition enable the monitoring of the separation outcome, i.e. mass, purity and charge, at various values of the applied voltage, of the mass of material and of the proportions in the granular mixture.