Assessment of precious metals positioning in waste printed circuit boards and the economic benefits of recycling

In this study, the distribution of precious metals in waste printed circuit boards was investigated and the economic value of recycling was assessed. Contacts of pins, slots, interfaces and the board surface in waste printed circuit boards were analyzed, and three types of precious metals were detected. The content of gold, silver and palladium ranged from 179.86 mg/kg to 3694.51 mg/kg, 809 mg/kg to 12320.51 mg/kg and 96.25 mg/kg to 117.49 mg/kg, respectively. Gold was distributed wildly in contacts of many slots and all interfaces, while contacts of only two interfaces (the cable and USB) contained palladium. The highest content of Au was found in contacts of the cable. Silver mainly concentrated on pins (metal foil contacts) of electronic components and its highest content was found in microchips. The economic value of recyclable precious metals in 1 t waste printed circuit boards was up to 2292.94 dollars, of which Au contributed 98%. This study indicates the prominent economic benefits of precious metal recovery from waste printed circuit boards. Moreover, the scientific information provide guidance for the directional and accurate recovery of precious metals from waste printed circuit boards.

Automated summary

This study investigates the distribution of precious metals in waste printed circuit boards and evaluates the economic value of recycling. Gold, silver, and palladium were detected in different parts of the boards, with gold being widely distributed and silver concentrated on the pins of electronic components. The economic value of recyclable precious metals in 1 ton of waste printed circuit boards reaches up to $2292.94, with gold contributing the most. This study highlights the economic benefits and provides guidance for the recovery of precious metals from waste printed circuit boards.