Recycling of Printed Circuit Boards

Printed circuit boards (PCBs) can be found in any piece of electrical or electronic equipment: nearly all electronic items, including calculators and remote control units, contain large circuit boards; an increasing number of white goods, as washing machines contains circuit boards for example in electronic timers. PCBs contain metals, polymers, ceramics and are manufactured by sophisticated technologies. Wastes from electric and electronic equipments (WEEE) show an increasing upward tendency: a recent annual estimation for WEEE was almost 6.5 million tonnes, and it has been predicted that by 2015 the figure could be as high as 12 million tonnes (Barba-Gutiérrez et al., 2008). A significant proportion of WEEE is constituted by PCBs which represent about 8% by weight of WEEE collected from small appliances (Waste & Resources Action Programme Project, WRAP 2009) and 3% of the mass of global WEEE (Dalrymple et al., 2007). However there is an increasing interest in the end-of-life management of polymers present in WEEE mainly due to high quotas of recycling and recovery set by legislation which can only be fulfilled by including the plastic fraction in recycling and recovery approaches. Furthermore, disposal of PCB in landfill is no longer accepted in developed countries because of environmental impact and loss of resources. So far recycling of waste PCBs is an important subject in terms of potential recovering of valuable products but several difficulties still exist due to environmental problems involved in end-of-life WEEE management. Due to its complex composition, PCBs recycling requires a multidisciplinary approach intended to valorise fibres, metals and plastic fractions and reduce environmental pollution, which are here reviewed in an attempt to offer a an overview of the latest results on recycling waste PCBs.