Thermal transformation of printed circuit boards at 500 °C forsynthesis of a copper-based product

This paper details the synthesis of copper-based products (i.e. Cu, Cu-Ni-Sn, Cu-Sn) from printed circuit boards (PCBs) using thermal transformation at 500 °C. The temperatures investigated in this paper aremuch lower than those used in conventional electronic waste smelting industries. This helps in reducing the energy requirements of the process opening up pathways for sustainable PCB processing technology. The resulting copper-based product comprises up to 94% metallic Cu, 2.5% Cu-Ni-Sn and 0.7% Cu-Sn alloys. Metallic Cu and Cu-Ni-Sn alloy are present in face centered cubic (FCC) form whereas Cu-Sn alloy possesses hexagonal closed packed (HCP) structure. XPS attests complete absence of oxides in metallic Cu. The copper product exhibits 4.57 × 10∧7 ± 0.084 Sm∧-1 electrical conductivity, equivalent to 78% IACS (International Annealed Copper Standard), which potentially enables its application in electrical switches or wire terminals.We have thus successfully developed a copper-based product from electronic waste, studied its properties and explored it from an application point of view.