Recovering valuable metals from Waste Printed Circuit Boards (WPCB): A short review

Abstract

In the modern era, metal usage can be traced in almost anything from simple household tools to complex electronic equipment. About 95 % of the electronic equipment surrounding us is built using components containing valuable metals, such as gold, silver, copper, palladium, and rare earths. Recycling electronic equipment offers a much richer resource than extracting metals from their respective ores. Printed circuit boards (PCBs) form about 3–6 % of the total electronic waste yet contain considerable quantities of precious metals. Most of the electronic waste (e-waste) that is disposed of, such as computers, mobile phones, televisions, printers, etc., are equipped with PCBs. These products are equipped with printed circuit boards(PCB) which are rich in valuable metals, including copper, aluminium, and gold. Recycling e-waste, especially PCBs, provides a route for economical and profitable extraction of valuable metals other than mining. Waste PCBs can be recycled using mechanical, pyrometallurgical, hydrometallurgical, electrometallurgical, and biometallurgical processes. In this review, the different technologies available for PCB recycling are compared, their limitations are highlighted to appreciate an environmentally friendly recovery of metals from the WPCBs. The PCBs feature a complex composition; therefore, it requires an intricate and novel approach to extract the specific metals. The review briefly analyses the different methods and techniques to extract the constituent elements and serves as a reliable reference for recycling WPCBs.