Aqueous Dissolution of Pyrochlore and Zirconolite in F--bearing Solutions


We have studied the aqueous durability of pyrochlore-structured yttrium-titanate (Y2Ti2O7) and Nd/Al-bearing zirconolite [(Ca0.8Nd0.2)Zr(Ti1.8Al0.2)O7] in both neutral and acidic solutions, with and without the presence of 0.001 M of NaF. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM) were used to characterize the composition, structure and morphology of the pyrochlore (Y2Ti2O7) and zirconolite surfaces, both before and after static dissolution testing at 90 and 150°C for four weeks. The leachates were also analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to estimate the individual elemental releases. The results show that the presence of F- ions only has a significant effect in acidic media on the dissolution behavior of pyrochlore and zirconolite. This detrimental effect is more pronounced for pyrochlore than zirconolite; the Y2Ti2O7 surface was replaced completely by alteration products after dissolution testing at 150°C for 4 weeks in acidic media with 0.001 M fluoride ions.

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  1. 1.

    B.B. Ebbinghaus, R.A. VanKonynenburg, F.J. Ryerson, E.R. Vance, M.W.A. Stewart, A. Jostsons, J.S. Allender, T. Rankin, J. Congdon, Ceramic Formulation for the Immobilization of Plutonium, Waste Management 98 (CD-ROM), Tucson, AZ, USA, March 5, 1998.

    Google Scholar 

  2. 2.

    B.D. Begg, W.J. Weber, R. Devanathan, J.P. Icenhower, S. Thevuthasan and B.P. McGrail in Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V (Ceramic Transactions, Vol 107), ed. G.T. Chandler and X. Feng, (Am. Ceram. Soc., Westerville, Ohio, USA, 2000) pp. 553–560.

  3. 3.

    K.L. Smith, Z. Zhang, P. McGlinn, D. Attard, H. Li, G.R. Lumpkin, M. Colella, T. McLeod, Z. Aly, E. Loi, S. Leung, K.P. Hart, M. Ridgway, W.J. Weber and S. Thevuthasan in Scientific Basis for Nuclear Waste Management XXVI, ed. R.J. Finch and D.B. Bullen, (Mat. Res. Soc. Symp. Proc. 757, Warrendale, PA, USA, 2003) pp. 289–296.

  4. 4.

    J. Malmstrom, E. Reusser, R. R. Giere, G.R. Lumpkin, M. Duggelin, D. Mathys and R. Guggenheim in Scientific Basis for Nuclear Waste Management XXII, ed. D.J. Wronkiewicz and J.H. Lee, (Mat. Res. Soc. Symp. Proc. 556, Warrendale, PA, USA, 1999) pp. 165–172.

  5. 5.

    J.C. Malmstrom, “Zirconolite: Experiments on the Stability in Hydrothermal Fluids”, Beitrage zur Geologie der Schweiz, Geotechnische Serie 93, (Schweizerische Geotechnische Kommission, ETH-Zentrum, Zurich, Switzerland, 2000).

    Google Scholar 

  6. 6.

    E.R. Vance, N. Dytlewski, K.E. Prince, K.P. Hart and E. Loi in Scientific Basis for Nuclear Waste Management XXIII, ed. R.W. Smith and D.W. Shoesmith, (Mat. Res. Soc. Symp. Proc. 608, Warrendale, PA, USA, 2000) pp. 379–385.

  7. 7.

    A.E. Ringwood, S.E. Kesson, K.D. Reeve, D.M. Levins and E.J. Ramm, “Synroc”, Radioactive Waste Forms for the Future, ed. W. Lutze and R.C. Ewing, (Elsevier, 1988) pp. 233–334.

    Google Scholar 

  8. 8.

    G. Leturcq, T. Advocat, K. Hart, G. Berger, J. Lacombe and A. Bonnetier, Amer. Mineral. 86, 871–880 (2001).

    CAS  Article  Google Scholar 

  9. 9.

    S.U. Aja, S.A. Wood and A.E. Williams-Jones, Applied Geochemistry 10, 603–620 (1995).

    CAS  Article  Google Scholar 

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The authors would like to thank Y. Zhang and P. McGlinn for valuable discussions, G. Leturcq, J. Hollis and M. Bhati for fabricating the samples, and K. Short for his help with the AFM measurements.

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Correspondence to Zhaoming Zhang.

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Zhang, Z., Li, H., Vance, E.R. et al. Aqueous Dissolution of Pyrochlore and Zirconolite in F--bearing Solutions. MRS Online Proceedings Library 824, 384–389 (2004).

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