Electro dynamic fragmentation of printed wiring boards as a preparation tool for their recycling

Abstract

The use of Electro Dynamic Fragmentation (EDF) enables selective fragmentation of materials through generating electrical discharges as a means of fracturing. Liberated materials can be thus processed downstream in a more efficient way especially when value-added End-of-Life (EoL) electronic equipment is recycled. The aim of this study was to assess the benefits of the EDF technology towards processing of EoL printed wiring boards (PWBs) in view their recyclability. Printed wiring boards were comminuted using EDF at three different settings and with a hammer mill for comparative experiment. The products coming out were characterized by optical microscopy, SEM and liberation oriented leaching. Subsamples from the various EDF stages were inspected to investigate the progress of cracks and degree of copper layers exposure. The different energy levels used during the EDF processing have resulted in different degrees of PWBs damages, starting from components removal to entire structure perturbation and size reduction. EDF has resulted in generation of a lesser amount of fines, however the optimal approach in view energy efficient post-processing of the studied PWBs was the combination between single-stage EDF for components removal only with subsequent shredding of the depopulated boards.