Editors: | F. Kongoli, M. Gaune-Escard, J. Dupont, R. Fehrmann, A. Loidl, D. MacFarlane, R. Richert, M. Watanabe, L. Wondraczek, M. Yoshizawa-Fujita, Y. Yue |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2019 |
Pages: | 177 pages |
ISBN: | 978-1-989820-00-1 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Spent salts coming from pyrochemical processing are composed of mixtures of NaCl, KCl, and CaCl2 with various dissolved/precipitated species according to the process used and the storage time and conditions.
In order to stabilize these materials, a pyrochemical treatment has been developed by CEA Valduc. It consists in carrying out two steps: pyro-oxidation [1] and distillation [2, 3].
Pyro-oxidation, also known as oxidation-chlorination, allows oxidizing An into a stable oxide: AnO2. This requires the use of Cl2 gas to remove excess carbonate through the exhaust of CO2 and O2 gases:
Ongoing work is underway on the stability of carbonate in salt mixtures. Preliminary results and literrature [4] suggest that carbonates ions can be completely decomposed into carbon dioxide and a stable oxide by simply changing the composition of the molten bath. Indeed, salts containing CaCl2 showed quick and total decomposition of carbonates.
Follow-up work will have to verify the experimental conditions for which the chlorination step can be replaced by a simple stirring or addition of CaCl2 to remove excess carbonates.