Numéro |
Radioprotection
Volume 40, May 2005
ECORAD 2004
|
|
---|---|---|
Page(s) | S277 - S283 | |
DOI | https://doi.org/10.1051/radiopro:2005s1-042 | |
Publié en ligne | 17 juin 2005 |
Radium behaviour during ferric oxi-hydroxides ageing
Institute for Radiological Protection and Nuclear Safety (IRSN), BP. 17, 92262 Fontenay-aux-Roses Cedex, France
In uranium mill tailings, oxides and oxi-hydroxides are responsible of about 70% of the radium immobilization, half being associated to amorphous forms (mainly iron and manganese oxides/oxi-hydroxides). With time, crystallization of these amorphous forms can occur, inducing a redistribution of radium between solids and solution. If the amount of mobile radium increases, the impact of these tailings on the environment may become significant.
The aim of this study is to determine the amount of 226Ra released in solution during the crystallization process of hydrous ferric oxi-hydroxide (HFO) containing 226Ra. A reproducible co-precipitation procedure is developed. The transformation of Ra-HFO co-precipitate in crystallized forms (goethite, hematite, ...) is studied by ageing amorphous solids at 40C in different solutions.
After co-precipitation, about 20% of the initial 226Ra present in solution is associated to amorphous HFO. At 40
C, whatever the solution composition (MES or NaClO4), the solid evolution is very slow and, after 3-5 months, no significant amount of crystalline form is noticeable. Simultaneously, the amount of 226Ra present in solution is constant in MES and NaClO4 medium. In comparison, 226Ra sorption shows off inclusion of 226Ra in Ra-HFO precipitate.
© EDP Sciences, 2005
Les statistiques affichées correspondent au cumul d'une part des vues des résumés de l'article et d'autre part des vues et téléchargements de l'article plein-texte (PDF, Full-HTML, ePub... selon les formats disponibles) sur la platefome Vision4Press.
Les statistiques sont disponibles avec un délai de 48 à 96 heures et sont mises à jour quotidiennement en semaine.
Le chargement des statistiques peut être long.