| Autor: |
Diallo S; Institut National de la Recherche Scientifique (Centre Eau Terre Environnement), Université du Québec, Québec, Canada., Tran LH; Institut National de la Recherche Scientifique (Centre Eau Terre Environnement), Université du Québec, Québec, Canada., Larivière D; Chemistry Department, Université Laval, Québec, Canada., Blais JF; Institut National de la Recherche Scientifique (Centre Eau Terre Environnement), Université du Québec, Québec, Canada. |
| Jazyk: |
angličtina |
| Zdroj: |
Environmental technology [Environ Technol] 2024 Nov 14, pp. 1-16. Date of Electronic Publication: 2024 Nov 14. |
| DOI: |
10.1080/09593330.2024.2423906 |
| Abstrakt: |
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 H 2 SO 4 solution for 30 min at a temperature of 20°C for REEs; (2) a 1 M H 2 SO 4 solution with 67 g H 2 O 2 /L for 180 min at 80°C for Cu and (3) a solution of 42 g thiourea/L in 0.1 M H 2 SO 4 and 9 g Fe 2 (SO 4 ) 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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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