Abstract
Recovery of rare-earth elements (REEs) from spent NdFeB magnets is receiving great attention because of high amount of neodymium and potential risk of environmental pollution. In this study, a novel environment-friendly hydrometallurgical route is proposed for efficient recovery of REEs during electrochemical leaching with sulfuric and oxalic acids. With proper adjustment of the electrolyte composition and operating conditions, effective separation of different elements is observed; a compact layer of REE oxalates in a purity of up to 93% is obtained on the cathode, while iron remains in the solution and as solid residue for further recovery. The mechanisms during the electro-leaching process were subsequently investigated and we propose that cathodic deposition of the REEs is due to electrostatic attraction of the REE-oxalate particles on the cathode. With this finding, selective recovery of REEs from spent magnets can be achieved. This study provides a new insight on electronic waste recycling by implementing principles of electrochemistry.
| Original language | English |
|---|---|
| Article number | 117362 |
| Journal | Separation and Purification Technology |
| Volume | 251 |
| DOIs | |
| State | Published - Nov 15 2020 |
| Externally published | Yes |
Funding
The authors thank the European Regional Development Fund 2014−2020 (project code A74334) for financial support. The authors are grateful to Dr. Liisa Puro and Dr. Toni Väkiparta for their kind support during this project and help in ICP and SEM/EDX measurements; Mohammadamin Esmaelli for his help in zeta potential measurements.
Keywords
- Adsorption
- Electrolysis
- NdFeB alloy
- Oxalic acid
- Rare-earth elements