Continuous operation of a fluidized-bed disk-type electrostatic separator for micronized plastic waste.

The objective of this work is to highlight the peculiarities of the continuous operating regime of a new tribo-aero-electrostatic separator for the recycling of plastics contained in micronized waste electrical and electronic equipment. The experiments were carried out with an ABS/PS mixture. The particles are charged by triboelectric effect in a fluidized bed in the presence of an electric field created between two disk electrodes connected to high voltage supplies of opposite polarities. The installation described in this paper has several control variables: the high voltage, the mass of the mixture initially introduced into the fluidized bed, the flow of fluidizing air and the rotation speed of the disk electrodes. The influence of each control variable of the machine on the efficiency of the separation was studied by simultaneously and continuously measuring the mass and the electrical charge of the collected products. The quality of the products obtained and the high hourly rates recommend this type of installation for industrial use.

Optimization of metals and plastics recovery from electric cable wastes using a plate-type electrostatic separator.

Plate-type electrostatic separators are commonly employed for the selective sorting of conductive and non-conductive granular materials. The aim of this work is to identify the optimal operating conditions of such equipment, when employed for separating copper and plastics from either flexible or rigid electric wire wastes. The experiments are performed according to the response surface methodology, on samples composed of either "calibrated" particles, obtained by manually cutting of electric wires at a predefined length (4mm), or actual machine-grinded scraps, characterized by a relatively-wide size distribution (1-4mm). The results point out the effect of particle size and shape on the effectiveness of the electrostatic separation. Different optimal operating conditions are found for flexible and rigid wires. A separate processing of the two classes of wire wastes is recommended.