P3-24 Synthesis of Sodalite by Hydrothermal Method and Characterizations H. Rabiller*, F. Bart*, JL. Dussossoy*, T. Advocat,* P. Perouty*, D. Rigaud*, V. Gori*, C.Mazzocchia**, F. Martini** *CEA/DEN/VRH/DTCD CEA VALRHO MARCOULE BP 17171 30207 Bagnols sur Cèze cedex, France
[email protected];
[email protected] ** Politecnico Di Milano P.zza L. da Vinci 32, 20133 Milano - Italy
[email protected] Abstract – Sodalite is a natural chloride mineral potentially interesting as a containment matrix for waste chloride salts containing fission products. CEA, within the PYROREP European contract, aimed at assessing the intrinsic stability of pure (Na) sodalite, then substituted sodalites, provided by the Politecnico di Milano team. Na-sodalite samples were synthesized by a hydrothermal process, and the substitution for Na by K was performed by ion exchange. Soxhlet tests were carried out: the initial alteration rates ranged from 0.16 g·m-2d-1 to 21 g·m-2d-1 for Na-sodalite and 0.30 g·m-2d-1 to 32.8 g·m-2d-1 for K-sodalite. The amplitude of these ranges is due to the open porosity of the pellets and thus a high uncertainty regarding the actual material surface area in contact with water. Leach tests under saturation conditions indicated preferential release of the Na and K cations bound to chlorine in the sodalite structure. INTRODUCTION with 6 tetrahedrons parallel to {111}. The rings Sodalite, (Na8[(Al6Si6O24)]Cl2), is a material define a series of tunnels in which the frequently cited [1],[2],[3] as a potentially intersections form large cavities occupied by interesting containment matrix for chloride salts chloride ions coordinated with sodium ions wastes containing fission products arising from (tetrahedrons).