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Molten Salt Synthesis of Zirconolite Polytypes

Published online by Cambridge University Press:  01 July 2014

M. R. Gilbert
M. R. Gilbert*
Affiliation:
AWE, Aldermaston, Reading, RG7 4PR, UK.
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Abstract

Zirconolite (CaZrTi2O7), a durable and compositionally flexible titanate ceramic for the immobilization of separated actinides, is currently the UK’s preferred candidate phase for the immobilization of plutonium dioxide arising from aqueous reprocessing. Here, its suitability as a waste-form for actinide chlorides arising from pyrochemical reprocessing is investigated through synthesis via a molten salt mediated reaction using a number of different salt eutectics (MgCl2:NaCl, CaCl2:NaCl and KCl:NaCl). It is found that the effectiveness of the molten salt synthesis of zirconolite is governed by the solubility of ZrO2 in the salt medium used; the synthesis proceeding via the formation of a perovskite (CaTiO3) intermediate which then reacts with ZrO2 to form zirconolite via a solution-diffusion mechanism. Most notably, in the KCl:NaCl eutectic different zirconolite polytypes are formed at different synthesis temperatures, with zirconolite-3T forming at 900 °C, giving way to zirconolite-2M at 1200 °C.

Keywords

Ticeramicwaste management
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1665: Symposium NW – Scientific Basis for Nuclear Waste Management XXXVII , 2014 , pp. 325 - 330
Copyright
Copyright © Materials Research Society 2014 

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References

REFERENCES

Nishimure, T., Koyama, T., Iizuka, M., Tanaka, H., Prog. Nucl. Energy, 32, 381 (1998).CrossRefGoogle Scholar
Taylor, I. N., Thompson, M. L., Johnson, T. R., Proceedings of the International Conference and Technology Exposition on Future Nuclear, 1, 690 (1993).Google Scholar
Lee, W. E., Grimes, R. W., Energy Materials, 1, 22 (2006).CrossRefGoogle Scholar
Sandland, T. O., Du, L.-S., Stebbins, J.F., Webster, J.D., Geochim. Cosmochim. Acta, 68, 5059 (2004).CrossRefGoogle Scholar
Segal, D., J. Mater. Chem., 7, 1297 (1997).10.1039/a700881cCrossRefGoogle Scholar
Zhang, S., Pak. Mater. Soc., 1, 49 (2007).CrossRefGoogle Scholar
Kimura, T., in: Advances in Ceramics – Synthesis and Characterization, Processing and Specific Applications, ed. Sikalidis, C. (InTech, 2011).Google Scholar
Smith, K. L., Lumpkin, G. R., Defects and Processes in the Solid State: Geoscience Applications, eds. Boland, J. N. and Fitzgerald, J. D. (Elsevier, 1993).Google Scholar
Rossell, H. J., Nature, 283, 282 (1980).CrossRefGoogle Scholar
Gatehouse, B. M., Grey, I. E., Hill, R. J., Rosell, H. J., Acta Cryst. B, 37, 306 (1981).CrossRefGoogle Scholar
Hand, M. L., Stennett, M. C., Hyatt, N. C., J. Eur. Ceram. Soc., 32, 3211 (2012).10.1016/j.jeurceramsoc.2012.04.046CrossRefGoogle Scholar
Stennett, M. C., Hand, M. L., Hyatt, N. C., Mater. Res. Soc. Symp. Proc., 1518, 97 (2013).CrossRefGoogle Scholar
Rietveld, H. M., Acta Cryst., 22, 151 (1967).10.1107/S0365110X67000234CrossRefGoogle Scholar
Rietveld, H. M., J. Appl. Cryst., 2, 65 (1969).CrossRefGoogle Scholar
Stennett, M. C., Hyatt, N. C., Gilbert, M. R., Livens, F. R., Maddrell, E. R., Mater. Res. Soc. Symp. Proc., 1107, 413 (2008).CrossRefGoogle Scholar
Gilbert, M. R., Selfslag, C., Walter, M., Stennett, M. C., Somers, J., Hyatt, N. C., Livens, F. R., IOP Conf. Ser.: Mater. Sci. Eng., 9, 12007 (2010).CrossRefGoogle Scholar