Feasibility of direct conversion of copper present in waste printed circuit boards to oxidation-resistant materials employing eco-benign iron(III) sulfate and ascorbic acid

This study presents the feasibility of an eco-benign, practical hydrometallurgical process for the recovery of Cu(0) as an oxidation-resistant material from waste printed circuit boards (WPCBs) with minimum chemical consumption. In leaching, metals were leached using Fe₂(SO₄)₃, and 98.4 ± 1.5% Cu(II) was achieved under optimum conditions (0.1 M Fe₂(SO₄)₃, 10 g/L pulp density, 25 °C, and 6 h). Then, 95.8 ± 0.3% Cu(0) was selectively recovered from multi-metal containing acidic leachate by a cementation method under the optimum conditions (0.3 M ascorbic acid, 70 °C, and 4 h). The as-recovered Cu(0) was characterized via quantitative and qualitative analyses and compared with a commercial Cu(0) as a reference material. As results, the high purity Cu(0) (99.2% Cu and 0.44% Ag) was recovered, and it was confirmed that the as-recovered Cu(0) can be used as an oxidation-resistant material owing to a trace amount of Ag. Finally, the economic feasibility of the developed process was evaluated based on the experimental results and the price of oxidation-resistant Cu in the e-commerce market ($10–50/kg). The minimum selling price of as-recovered Cu(0) can be estimated to be $26.16 per kg, which is a reasonable market price for oxidation-resistant Cu(0).