| Autor: |
A. Laplace, C. Hamel, Pierre Chamelot, E. Walle, Pierre Taxil, O. Dugne |
| Rok vydání: |
2007 |
| Předmět: |
|
| Zdroj: |
Electrochimica Acta. 52:3995-4003 |
| ISSN: |
0013-4686 |
| DOI: |
10.1016/j.electacta.2006.11.018 |
| Popis: |
This study focused on the electroreduction process of uranium cations in molten fluorides. It involved cyclic voltammetry, chronopotentiometry with and without current reversal, and square wave voltammetry. The results indicate a two-step reduction process for uranium(IV). The first step U(IV)/U(III) exchanging one electron corresponds to a soluble/soluble system and is limited by U(IV) diffusion with D U(IV) = 1.25 ± 0.35 × 10 −5 cm 2 s −1 in LiF–NaF at 720 °C. In order to perform a thorough study of the second step U(III)/U(0) in the reduction process, the melt was chemically reduced in U(III) with U metal as reducing agent. Alternatively to the use of LiF–NaF where U metal is unstable at 720 °C, the chemical reduction of U(IV) in U(III) was performed in a LiF–CaF 2 –UF 4 solution containing U metal at 810 °C. It has been confirmed that the reduction of U(III) proceeds in one step exchanging three electrons and by a diffusion controlled process with D U(III) = 2.2 ± 0.7 × 10 −5 cm 2 s −1 in LiF–CaF 2 at 810 °C. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect