Nuclear waste immobilization into structure of zirconolite by Complex Sol Gel Process

Abstract

Zirconolite (CaZrTi 2 O 7 ) is one of the components of Synroc materials, which are regarded throughout the world nuclear as the second generation of high-level nuclear waste forms. The zirconolite phase was synthesized by a sol-gel method, with one variant of the method making use of ascorbic acid as a strong complexing agent. Into the structure of the zirconolite was incorporated 10 mol% Sr. Undoped and doped samples were examined by thermal analyses and X-ray diffraction. Addition of ascorbic acid to the sols lowered the firing temperature and promoted formation of the zirconolite phase.

Archives of Metallurgy and Materials

“…The method of synthesis of perovskite-type Synroc by the method of a CSGP has been described in our previous publications in details [3,4]. In this work, TiCl 4 was dissolved in concentrated HCl to form a 4 M Ti solution.…”

“…Different types of Synroc with unique structures could hold many forms of radioactive ions according to their chemical characters and unique structures. The method of synthesis has been reported in our recent publications in 2014 [3,4]. In the present work, developed at Institute of Nuclear Chemistry and Technology the Complex Sol-Gel Process (CSGP), previously used for synthesis various types' ceramic materials [3][4][5][6][7], was applied to synthesize the perovskite-rutile-type Synroc.…”

“…The method of synthesis has been reported in our recent publications in 2014 [3,4]. In the present work, developed at Institute of Nuclear Chemistry and Technology the Complex Sol-Gel Process (CSGP), previously used for synthesis various types' ceramic materials [3][4][5][6][7], was applied to synthesize the perovskite-rutile-type Synroc. To simulate the incorporation process of the high level nuclear waste into a matrix, ionic liquid forms of non-radioactive Co, Cs, Nd and Sr, were used.…”