Eco-friendly and cost-effective strategies for metals recovery from printed circuit boards

TitleEco-friendly and cost-effective strategies for metals recovery from printed circuit boards
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2019
AuthorsPietrelli, L., Ferro S., and Vocciante M.
JournalRenewable and Sustainable Energy Reviews
KeywordsChemical substance, Chlorine compounds, Cost effective strategies, Cost effectiveness, Economic sustainability, electronic waste, Environmental impact, Hybrid solution, Hydro-metallurgical treatment, leaching, Metal recovery, Metals, Microwave digestion, Printed circuit board (PCBs), printed circuit boards, Program processors, Strategic considerations, Sustainable development, Timing circuits, Waste treatment

The possible optimization of metal recovery from Printed Circuit Boards (PCBs)and Central Processing Units (CPUs)has been investigated. Usual practice is to recover primarily the metals with the highest market price. In contrast, the present work shows how strategic considerations of the value share (%)of metals content and data regarding the environmental impact of their recovery can instruct about the best strategies to adopt, pointing at the metals to be recovered as a priority depending on the case. An accurate PCBs’ characterization carried out through microwave digestion with a mixture of HNO3, HF and HCl, is a first essential step of the procedure. Then, metals are recovered through chemical leaching with different chemical substances, exploiting both chemical and physical steps. A proposal is presented to improve the environmental and economic sustainability of the treatment of PCBs, which provides for the initial recovery of Cu, Pb and Sn from the whole boards, through leaching with 6M HNO3, followed by the recovery of gold and other precious metals from the board components once removed and appropriately crushed. Although unusual, the recovery procedure can be adapted accordingly, allowing greater profits, easier management and higher metals recovery rates. © 2019 Elsevier Ltd


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