Zirconolite Matrices for the Immobilization of REE–Actinide Wastes
Sergey V. Yudintsev,
Maximilian S. Nickolsky,
Michael I. Ojovan,
Olga I. Stefanovsky,
Victor I. Malkovsky,
Amina S. Ulanova,
Lewis R. Blackburn
Affiliations
Sergey V. Yudintsev
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences, Staromonetny Lane, 35, 119017 Moscow, Russia
Maximilian S. Nickolsky
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences, Staromonetny Lane, 35, 119017 Moscow, Russia
Michael I. Ojovan
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences, Staromonetny Lane, 35, 119017 Moscow, Russia
Olga I. Stefanovsky
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, 119071 Moscow, Russia
Victor I. Malkovsky
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences, Staromonetny Lane, 35, 119017 Moscow, Russia
Amina S. Ulanova
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences, Staromonetny Lane, 35, 119017 Moscow, Russia
Lewis R. Blackburn
Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
The structural and chemical properties of zirconolite (ideally CaZrTi2O7) as a host phase for separated REE–actinide-rich wastes are considered. Detailed analysis of both natural and synthetic zirconolite-structured phases confirms that a selection of zirconolite polytype structures may be obtained, determined by the provenance, crystal chemistry, and/or synthesis route. The production of zirconolite ceramic and glass–ceramic composites at an industrial scale appears most feasible by cold pressing and sintering (CPS), pressure-assisted sintering techniques such as hot isostatic pressing (HIP), or a melt crystallization route. Moreover, we discuss the synthesis of zirconolite glass ceramics by the crystallization of B–Si–Ca–Zr–Ti glasses containing actinides in conditions of increased temperatures relevant to deep borehole disposal (DBD).
