Application of triboelectric separation to improve the usability of nonmetallic fractions of waste printed circuit boards: Removing inorganics

The recovery of metals from waste printed circuit boards (WPCBs) has been studied for a long time because of the high economic value of these metals. The low usability of the nonmetallic fraction (NMF) of WPCBs caused by inorganics makes its industrial reuse difficult. Removal of inorganics by triboelectric separation with the aim of improving the usability of NMF was investigated using a lab triboelectric separation system. After separation, a new composite was produced by compounding 20 wt% NMF and 80 wt% high-density polyethylene (HDPE). The mechanical properties of each composite were compared, and the surface morphology was analyzed with a scanning electron microscope (SEM). The separation results demonstrated that inorganics were removed and collected in a groove that was closed to a negative plate. Mechanical property testing showed that the removal of inorganics could improve the usability of NMF. Both the flexural and impact strengths of the composites that were filled by NMF without inorganics were obviously improved. The SEM image indicated that air holes and faultage caused by glass fiber agglomerations and poor compatibility between HDPE and inorganics were the main features contributing to composites with poor mechanical properties. (C) 2016 Elsevier Ltd. All rights reserved.