Ricerc@Sapienza

The effect of a preliminary acid leaching for the recovery of gold by thiourea from printed circuit boards (PCBs) of spent mobile phones, was investigated. Preliminary leaching is aimed to recover copper in the leachate that would compete with gold in the successive leaching of the residue with thiourea, thus preventing the formation of the gold-thiourea complex. Two hydrometallurgical routes were tested for the recovery of copper first, and gold after.

The possible optimization of metal recovery from Printed Circuit Boards (PCBs) and Central Processing Units (CPUs) has been investigated. Usual practice is to primarily recover 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.

In this study, a methodological approach based on micro X-ray fluorescence
(micro-XRF) was developed in order to characterize end-of-life (EOL) printed circuit boards
(PCB) from smartphones. An in-depth recognition of chemical elements on the PCB allows
to set up an optimal processing strategy for recycling purposes. Moreover, a good
knowledge of PCB composition can help to correctly manage such a waste maximizing
the recovery of base, rare and precious metals. The possibility to carry out analyses both