Diallo, Salmata; Tran, Lan Huong 
ORCID: https://orcid.org/0000-0003-3764-1680; Larivière, Dominic et Blais, Jean-François ORCID: https://orcid.org/0000-0003-3087-4318
(2025).
Selective leaching of rare earths, base metals and precious metals from used smartphones.
Environmental Technology
, vol. 46
, nº 12.
pp. 2149-2164.
DOI: 10.1080/09593330.2024.2423906.
Résumé
Discarded smartphones represent a valuable source of rare earths (REE), base metals and precious metals. This study focussed on the optimisation of three-stage selective leaching conditions for REE, copper and precious metals (Au and Ag), respectively, contained in printed circuit boards (PCBs) found in end-of-life smartphones. The effects of several leaching conditions, such as sulphuric acid and thiourea concentrations, were investigated using a statistical approach based on a design of experiments using Box–Behnken methodology. Optimum leaching efficiencies were achieved when PCB powder was contacted (solid concentration of 100 g/L) with (1) a 0.2 M H2SO4 solution for 30 min at a temperature of 20°C for REEs; (2) a 1 M H2SO4 solution with 67 g H2O2/L for 180 min at 80°C for Cu and (3) a solution of 42 g thiourea/L in 0.1 M H2SO4 and 9 g Fe2(SO4)3/L for 120 min at 20°C for Au and Ag. Using these optimal conditions, a complete leaching procedure included an REE solubilisation step and a base metal leaching step, both repeated twice, and a precious metal leaching step. This procedure solubilised 91% of the REE, 100% of the copper, 98% of the gold and 87% of the silver contained in the PCB powder during their respective leaching stages.
| Type de document: | Article |
|---|---|
| Mots-clés libres: | selective leaching; rare earth element; precious metals; copper; E-waste |
| Centre: | Centre Eau Terre Environnement |
| Date de dépôt: | 14 juill. 2025 14:24 |
| Dernière modification: | 14 juill. 2025 14:24 |
| URI: | https://espace.inrs.ca/id/eprint/16463 |
Gestion Actions (Identification requise)
 |
Modifier la notice |