Title Challenges on Multilyer Composites Desintegration and Materials Recovering for Waste Printed Circuit Boards
Authors Denafas, G ; Miliauskas, G ; Andriukonis, E ; Griškonis, E ; Pitak, I ; Makarevičius, V ; Baltušnikas, A ; Kriukienė, R ; Šleiniūtė, A ; Ivanauskas, R ; Goljandin, D ; Blumbergs, E ; Shishkin, A
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Is Part of Book of Abstracts International Joint Conference Polymers 2025, composites 2025 and 3bs materials tech 2025 16 - 18 April 2025 Albufeira, Portugal.. Alfubeira : SETCOR. 2025, p. 23
Keywords [eng] circuit boards ; dielectric layer ; conductive layer ; mechanical treatment ; disolution ; hydrometallurgical extraction
Abstract [eng] Printed circuit boards (PCBs) are one of the most common types of multilayer composites used in many electrical and electronic equipment devices. The most important layers are Conductive Layer, Dielectric Layer, Solder Mask Layer, Silkscreen Layer. In most cases, PCBs with multiple conductive and interconnected layers are formed. The dielectric layer can be formed from such materials as FR-4 (composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant), CEM materials, polyimides, Teflon, etc. The choice of these materials depends on the nature of the PCB operation. Copper is usually used for the conductive layer, for specialized PCB – also aluminum, silver, gold. Due to technological development the nature of materials used for PCB layers is constantly changing. For example flexible PCBs are increasingly being used instead of rigid PCBs. And this affects the process of recovering valuable materials at the end of their life time due to the variety and different properties of these materials. Generally, the process of recovering materials from used PCBs consists the main stages - mechanical crushing and separation, hydrometallurgical extraction and selective concentration of different valuable metals. At the industrial level, mechanical processes are mainly used, while hydrometallurgical extraction presents many challenges, so the right answers are still being sought at the laboratory level. Attention should also be drawn to the fact that when FR-4 is used for the dielectric layer, so after mechanical crushing it is also appropriate to recover the epoxy resins by dissolution them with solvents, which is impossible to apply to other types of dielectric layers. This paper shares the laboratory experience of recovering valuable materials from computer PCBs and push-button cell phone PCBs. Many current challenges are started from the sorting of used PCBs and continued on further hydrometallurgical extraction of metals, when it comes to the efficiency of leaching of rare and precious metals from the dielectric layer. Keywords: printed circuit boards, dielectric layer, conductive layer, mechanical treatment, disolution, hydrometallurgical extraction.
Published Alfubeira : SETCOR
Type Conference paper
Language English
Publication date 2025