Modified tribo-charging device for the electrostatic separation of plastics from granular industrial wastes

Tribo-electrostatic separation is the solution of choice for the selective sorting of various plastics contained in a granular mixture. This work is aimed at validating the efficiency of a modified compressed-air-operated tribo-charging device for the electrostatic separation of mixed granular plastics originating from industrial waste. The experiments are carried out with a mixture of mm-size orange and beige PVC granules, using a free-fall electrostatic separator. At optimum operating conditions, 93% of the orange PVC and 96% of the beige PVC were recovered at purities higher than, respectively, 99% and 95%. The numerical simulation of charged particles trajectories facilitates the interpretation of the experimental results and the analysis of the factors that affect the efficiency of the separation process: high-voltage level, configuration of the electrodes system, and position of the feeding unit.