Recycling of waste printed circuit boards by mechanical milling

Waste printed circuit boards (WPCBs) - a common type of e-waste consisting of electronic components with a significant amount of rare and precious metals as well as glass fiber composites. The development of WPCB retreatment technology through mechanical methods, resulting in metallic and non-metallic waste fractions, can be efficiently classified as enriched concentrate. The research presented in this paper highlights the potential trends for recycling WPCBs. The integration of impact milling for WPCBs is a promising technology for the partitioning and fragmentation of different components and for the separation of fractions. The mechanical size-reduction and separation technology of pre-crushed WPCBs, using direct and separative disintegrator milling, has been compared with other technologies (hammer milling and high voltage fragmentation). The main parameters, such as the specific energy ([E.sub.S]) of WPCB treatment and the rate of separation of different phases, were studied. As preliminary results show the optimal parameters of partitioning of the metallic and non-metallic parts, fragmentation and delamination (specific energy of treatment and rate of separation) by disintegrator milling were proposed. Keywords: WPCBs, impact milling, partitioning, fragmentation, separation, waste metal, glass fiber.