Separation of PVC and Rubber from Covering Plastics in Communication Cable Scrap by Tribo-Charging

Abstract

Triboelectrostatic separation of PVC and rubber from covering plastics in communication cable scrap has been performed. In this work, particles charged as positive (+) and negative (−) according to the difference of work function of each material after tribo-charging can be separated through an opposite electric field. In charger material selection tests using a vertical-reciprocation charger, PVC and rubber particles in the covering plastics were charged with the opposite polarity in the charger material made of PP, HDPE, or PET. The difference of charge density (charge to mass ratio, nC/g) of the PVC and rubber was higher in the tribo-charger made of HDPE. Furthermore, in lab-scale triboelectrostatic experiments for separating the PVC and rubber, the charging efficiency of the mixed PVC and rubber increased when the air velocity was adjusted to over 8.2 m/s. The charge density, the electrode potential, and splitter position needed for the separation of the PVC were determined to be 25 nC/g, 30 kV and +2 cm, respectively. In the optimum conditions, we developed a separation technique that can separate up to 99.8% PVC grade with 95.0% of recovery from the covering plastics.