| Title |
Simple gold recovery from e-waste leachate by selective precipitation using a quaternary ammonium salt |
| ID_Doc |
24600 |
| Authors |
Nogueira, AFM; Carreira, ARF; Vargas, SJR; Passos, H; Schaeffer, N; Coutinho, JAP |
| Title |
Simple gold recovery from e-waste leachate by selective precipitation using a quaternary ammonium salt |
| Year |
2023 |
| Published |
|
| DOI |
10.1016/j.seppur.2023.123797 |
| Abstract |
Precipitation processes, if selective, present a simple and economical alternative for the recovery of critical metals from primary and secondary ores including electronic wastes. In this work, the recovery of gold by precipitation from both mono-elemental solutions and real CPU leach solution was demonstrated using hydro-philic quaternary ammonium salts. The gold precipitation yield is shown to be dependent on the apolar volume of the precipitant, with the addition of tetrabutylammonium-based salts resulting in the recovery of over 90 % of gold from synthetic solutions. The origin of gold precipitation selectivity relative to common metal ions upon addition of tetrabutylammonium nitrate ([N4444][NO3]) was assigned by X-ray crystal structure to the formation of size selective apolar cavity between neighbouring [N4444]+ cation and the [AuCl4]- anion. Following opti-misation as a function of the gold to precipitant molar ratio, aqua regia concentration and time, approximately 70 % of gold could be recovered from waste CPU leach solution with a final purity of 91.4 % (mol/mol). [N4444] [NO3] proved to be a versatile gold extractant and could be further applied as part of an acidic aqueous biphasic system at higher aqua regia concentrations were precipitation yields decreased, ensuring a selective gold recovery across a range of leachate conditions. The disclosed results improve the circularity of gold by providing a new avenue for its simple recycling. |
| Author Keywords |
Recycling; Electronic waste; Molecular recognition; Circular economy; Ionic liquid |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Science Citation Index Expanded (SCI-EXPANDED) |
| EID |
WOS:000982015100001 |
| WoS Category |
Engineering, Chemical |
| Research Area |
Engineering |
| PDF |
https://doi.org/10.1016/j.seppur.2023.123797
|