2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 6: Coatings, Cement, Rare Earth & Ferro-alloys
| Editors: | Kongoli F, Yildirim H, Hainer S, Hofmann K, Proske T, Graubner C.A., Albert B |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 200 pages |
| ISBN: | 978-1-987820-29-4 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Electrodeposition of Rare Earth Metals from BMPTFSI Ionic Liquid
Dimitrios Panias1; Evangelos Bourbos2; Ioanna Giannopoulou2;1, Athens, Greece; 2NATIONAL TECHNICAL UNIVERSITY OF ATHENS, Athens, Greece;
Type of Paper: Regular
Id Paper: 455
Topic: 11
Abstract:
Production of rare earth metals and alloys is conventionally performed by high temperature molten salts electrolysis, which creates highly corrosive environment and demands high energy consumption. Recently, the use of organic solvents has been implemented; however, they were considered inadequate, due to their high volatility and flammability. Ionic liquids (IL) gain increasing attention in the recent years as electrolytes for the recovery of drastic metals. The type of cations and anions adjust the properties for ILs, such as low melting points, chemical and thermal stability, negligible vapour pressure, ability to dissolve a wide range of compounds, ionic conductivity and broad electrochemical window.
The reduction of rare earth cations (e.g. La, Sm, Nd, Dy) to the metallic state and their subsequent electrodeposition in BMPTFSI is studied. This hydrophobic ionic liquid presents a wide electrochemical window and a satisfying ionic conductivity rendering it a promising electrolyte for the rare earths reduction. A study of different systems in order to address the dissolution problem of rare earths in ionic liquids and the problem of the anodic reaction during cathodic polarization has also been realized. Cyclic voltammetry (CV) performed on a Pt electrode in a three electrode cell revealed that rare earth cations can be reduced to the metallic state in the above mentioned ionic liquid. Furthermore, the electrodeposition of rare earths was realised on a copper substrate, under potentiostatic conditions for 5h at -3.1 V at 25°C and the electrodeposits were examined in SEM and EDS analysis, revealing rare earths electrodeposition.
It is concluded that BMPTFSI is an appropriate ionic liquid for rare earths electrodeposition and the optimum conditions for achieving concentrated solutions and hindering decomposition of the ionic liquid in the anode are presented.