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Low-temperature aqueous alteration of crystalline pyrochlore: correspondence between nature and experiment

Published online by Cambridge University Press:  05 July 2018

T. Geisler ,
J. Berndt ,
H.-W. Meyer ,
K. Pollok  and
A. Putnis
T. Geisler
Affiliation:
Institut für Mineralogie, University of Münster, Corrensstr. 24, 48149 Münster, Germany
J. Berndt
Affiliation:
Institut für Mineralogie, University of Münster, Corrensstr. 24, 48149 Münster, Germany
H.-W. Meyer
Affiliation:
Institut für Physikalische Chemie, University of Münster, Corrensstr. 30, 48149 Münster, Germany
K. Pollok
Affiliation:
Institut für Mineralogie, University of Münster, Corrensstr. 24, 48149 Münster, Germany
A. Putnis
Affiliation:
Institut für Mineralogie, University of Münster, Corrensstr. 24, 48149 Münster, Germany
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Abstract

Pyrochlore has been considered as a waste form to immobilize high-level nuclear waste such as excess weapons-grade plutonium. In order to study the aqueous stability of pyrochlore, we have carried out hydrothermal experiments with a natural microlite (Nb + Ta > 2Ti; Ta ⩾ Nb) at 175°C in a neutral and acidic solution for 14 days. The starting material and the experimental products were studied by electron microprobe, backscattered electron (BSE) imaging, powder infrared (IR) and micro-Raman spectroscopy, and powder X-ray diffractrometry (XRD). The microlite has small U (∼200 ppm) and Th (∼800 ppm) contents and is crystalline. The hydrothermal treatment in a solution containing l mol/l HCl and l mol/l CaCl2 causes the partial replacement of the microlite (up to ∼10 μm) by a new pyrochlore phase. This new phase is characterized by a larger unit-cell volume and contains a large number of vacancies at the A site (A = Ca, Na) as well as anion vacancies, molecular water, and possibly OH groups. Analyses of the experimental fluid further revealed that U was also selectively lost to the solution. Treatment in pure water did not produce reaction zones detectable by BSE imaging or powder XRD. However, significant spectral changes in powder IR spectra of the reaction product and the detection of Na and Ca in the solution indicate that the microlite has also reacted in pure water. The experimental alteration features bear a remarkable resemblance to those seen in naturally altered microlite samples, suggesting that short-term experimental results can be applied to natural systems and vice versa in order to evaluate the long-term stability of a pyrochlore waste form.

Keywords

pyrochloremicroliteaqueous alterationnuclear waste
Type
Research Article
Information
Mineralogical Magazine , Volume 68 , Issue 6 , December 2004 , pp. 905 - 922
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2004

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References

Barrer, R.M. (1978) Zeolites and Clay Minerals as Sorbents and Molecular Sieves. Academic Press, New York.Google Scholar
Begg, B.D., Hess, N.J., Weber, W.J., Devanathan, R., Icenhower, J.P., Thevuthasan, S. and McGrail, B.P. (2001) Heavy-ion irradiation effects on structures and acidic dissolution of pyrochlores. Journal of Nuclear Materials, 288, 208–216.CrossRefGoogle Scholar
Bogdanov, R.V., Batrakov, Y.F., Puchkova, E.V., Sergeev, A.S. and Burakov, B.E. (2002) Study of natural minerals of U-pyrochlore type structure as analogues of plutonium ceramic waste form. Materials Research Society Symposium Proceedings, 713, JJ2.2–JJ2.8.CrossRefGoogle Scholar
Butler, M.A. and Biefeld, R.M. (1979) NMR study of proton motion in the defect pyrochlores HTaWO6 and HTaWO6-H2O. Physical Review, 19, 5455–5462.CrossRefGoogle Scholar
Casey, W.H., Westrich, H.R., Banfield, J.F., Ferruzzi, G. and Arnold, G.W. (1993) Leaching and reconstruction at the surfaces of dissolving chain-silicate minerals. Nature, 366, 253–255.CrossRefGoogle Scholar
Chakoumakos, B.C. (1984) Systematics of the pyrochlore structure type, ideal A2B2X6Y. Journal of Solid State Chemistry, 53, 120–129.CrossRefGoogle Scholar
Chowdhry, U., Barkley, J.R., English, A.D., Sleight, A.W., du Pont de Nemours, E.I., Company, Inc. (1982) New inorganic proton conductors. Materials Research Bulletin, 17, 917–933.CrossRefGoogle Scholar
Dickens, P.G. and Weller, M.T. (1986) Structure and proton mobility in defect pyrochre (H2O)xH2Ta2O6 . Solid State Communications, 59, 569–573.CrossRefGoogle Scholar
Ercit, T.S., Hawthorne, F.C. and Černý, P. (1994) The structural chemistry of kalipyrochlore, a ‘hydropyrochlore’. The Canadian Mineralogist, 32, 415–420.Google Scholar
Ewing, R.C. (1999) Nuclear waste forms for actinides. Proceedings of the National Academy of Science, USA, 96, 3432–3439.CrossRefGoogle ScholarPubMed
Ewing, R.C. (2001) The design and evaluation of nuclear-waste forms: Clues from mineralogy. The Canadian Mineralogist, 39, 697–715.CrossRefGoogle Scholar
Ewing, R.C., Weber, W.J. and Lian, J. (2004) Nuclear waste disposal–pyrochlore. A2B2O7: Nuclear waste form for the immobilization of plutonium and “minor” actinides. Journal of Applied Physics, 95, 1–23.Google Scholar
Farmer, V.C. (1974) The Infrared Spectra of Minerals. Monograph 4, Mineralogical Society, London, 539 pp.CrossRefGoogle Scholar
Geisler, T., Ulonska, M., Schleicher, H., Pidgeon, R.T. and van Bronswijk, W. (2001) Leaching and differential recrystallization of metamict zircon under experimental hydrothermal conditions. Contributions to Mineralogy and Petrology, 141, 53–65.CrossRefGoogle Scholar
Geisler, T., Pidgeon, R.T., van Bronswijk, W. and Kurtz, R. (2002) Transport of uranium, thorium, and lead in metamict zircon under low-temperature hydrothermal conditions. Chemical Geology, 191, 141–154.CrossRefGoogle Scholar
Geisler, T., Pidgeon, R.T., Kurtz, R., van Bronswijk, W. and Schleicher, H. (2003 a) Experimental hydrothermal alteration of partially metamict zircon. American Mineralogist, 86, 1496–1518.CrossRefGoogle Scholar
Geisler, T., Rashwan, A.A., Rahn, M., Poller, U., Zwingmann, H., Pidgeon, R.T. and Schleicher, H. (2003 b) Low-temperature hydrothermal alteration of natural metamict zircons from the Eastern Desert, Egypt. Mineralogical Magazine, 67, 485–508.CrossRefGoogle Scholar
Geisler, T., Trachenko, K., Ríos, S., Dove, M. and Salje, E.K.H. (2003 c) Impact of self-irradiation damage on the aqueous durability of zircon (ZrSiO4): Implications for its suitability as nuclear waste form. Journal of Physics: Condensed Matter, 15, L597–L605.Google Scholar
Geisler, T., Zhang, M. and Salje, E.K.H. (2003 d) Recrystallization of almost fully amorphous zircon under hydrothermal conditions: An infrared spectroscopic study. Journal of Nuclear Materials, 320, 280–291.CrossRefGoogle Scholar
Geisler, T., Burakov, B., Yagovkina, M., Garbuzov, V., Zamoryanskaya, M., Zirlin, V. and Nikolaeva, L. (2004) Structural recovery of self-irradiated natural and 238Pu-doped zircon in an acidic solution at 175°C. Journal of Nuclear Materials, 336, 22–30.CrossRefGoogle Scholar
Hellman, R., Penisson, J.-M., Hervig, R.L., Thomassin, J.-H. and Abrioux, M.-F. (2003) An EFTEM/ HRTEM high-resolution study of the near surface of labradorite feldspar altered at acidic pH: evidence for interfacial dissolution-reprecipitation. Physics and Chemistry of Minerals, 30, 192–197.CrossRefGoogle Scholar
Hogarth, D.D. (1977) Classification and nomenclature of the pyrochlore group. American Mineralogist, 62, 403–410.Google Scholar
Holland, T.J.B. and Redfern, S.A.T. (1997) Unit-cell refinement from powder diffraction data: the use of regression diagnostics. Mineralogical Magazine, 61, 65–77.CrossRefGoogle Scholar
Icenhower, J.P., McGrail, B.P., Weber, W.J., Begg, B.D., Hess, N.J., Rodriguez, E.A., Steele, J.L., Brown, C.F. and O'Hara, M.J. (2002) Dissolution of A2Ti2O7 (A = Y3+, Gd3+ or Lu3+) pyrochlore by experiment at pH = 2, T = 90°C: Evidence for solubility control using a linear free energy model. Materials Research Society Symposium Proceedings, 713, JJ6.2.1–JJ6.2.7.CrossRefGoogle Scholar
Janssen, A. (2004) Die Kinetik und pH-Abhängigkeit der hydrothermalen Alteration von kristallinem Pyrochlor (Mikrolit) in HCl-saurer Lösung bei 200°C. Unpublished Bachelor thesis, University of Münster.Google Scholar
Krivokoneva, G.K. and Sidorenko, G.A. (1971) The essence of the metamict transformation in pyrochlores. Geochemistry International, 2, 113–122.Google Scholar
Langmuir, D. (1978) Uranium solution-mineral equilibria at low temperatures with applications to sedimentary ore deposits. Geochimica et Cosmochimica Acta, 42, 547–569.CrossRefGoogle Scholar
Lee, J.K.W. and Tromp, W. (1995) Self-induced fracture generation in zircon. Journal of Geophysical Research, 100, B9, 17753–17770.CrossRefGoogle Scholar
Leturcq, G., Advocat, T., Hart, K., Berger, G., Lacombe, J. and Bonnetier, A. (2001) Solubility study of Ti,Zr–based ceramics designed to immobilize long–lived radionuclide. American Mineralogist, 86, 871–880.CrossRefGoogle Scholar
Lottermoser, B.G. and England, B.M. (1988) Compositional variation in pyrochlores from the Mt Weld carbonatite laterite, Western Australia. Mineralogy and Petrology, 38, 37–51.CrossRefGoogle Scholar
Lumpkin, G.R. (2001) Alpha-decay damage and aqueous durability of actinide host phases in natural phases. Journal of Nuclear Materials, 289, 136–166.CrossRefGoogle Scholar
Lumpkin, G.R. and Ewing, R.C. (1992) Geochemical alteration of pyrochlore group minerals: Microlite subgroup. American Mineralogist, 77, 179–188.Google Scholar
Lumpkin, G.R. and Ewing, R.C. (1995) Geochemical alteration of pyrochlore group minerals: Pyrochlore subgroup. American Mineralogist, 80, 732–743.CrossRefGoogle Scholar
Lumpkin, G.R. and Ewing, R.C. (1996) Geochemical alteration of pyrochlore group minerals: Betafite subgroup. American Mineralogist, 81, 1237–1248.CrossRefGoogle Scholar
Lumpkin, G.R. and Mariano, A.N. (1999) Natural occurrence and stability of pyrochlore in carbonatites, related hydrothermal systems, and weathering environments. Materials Research Society Symposium Proceedings, 412, 831–838.CrossRefGoogle Scholar
Lumpkin, G.R., Chakoumakos, B.C. and Ewing, R.C. (1986) Mineralogy and radiation effects of microlite from the Harding pegmatite, Taos County, New Mexico. American Mineralogist, 71, 569–588.Google Scholar
Lumpkin, G.R., Day, R.A., McGlinn, P.J., Payne, T.E., Gieré, R. and Williams, C.T. (1999) Investigation of the long-term performance of betafite and zirconolite in hydrothermal veins from Adamello, Italy. Materials Research Society Symposium Proceedings, 556, 793–800.CrossRefGoogle Scholar
Lumpkin, G.R., Ewing, R.C., Williams, C.T. and Mariano, A.N. (2001) An overview of the crystal chemistry, durability, and radiation damage effects of natural pyrochlore. Materials Research Society Symposium Proceedings, 663, 921–934.CrossRefGoogle Scholar
Lutze, W. and Ewing, R.C. (1988) Radioactive Waste Forms for the Future. North Holland Physics Publishing, Amsterdam, The Netherlands.Google Scholar
Mihailova, B., Stoyanov, S., Gaydarov, V., Gospodinov, M. and Konstantinov, L. (1997) Raman spectroscopy study of pyrochlore Pb2Sc0.5Ta1.506.5 crystals. Solid State Communications, 103, 623–627.CrossRefGoogle Scholar
Mihailova, B., Savatinova, I., Savova, I. and Konstantinov, L. (2000) Modeling of Raman spectra of H:LiNbO3 . Solid State Communications, 116, 11–15.CrossRefGoogle Scholar
Nasraoui, M. and Bilal, E. (2000) Pyrochlores from the Lueshe carbonatite complex (Democratic Republic of Congo): a geochemical record of different alteration stages. Journal of Asian Earth Science, 18, 237–251.CrossRefGoogle Scholar
Nasraoui, M., Bilal, E. and Gibert, R. (1999) Fresh and weathered pyrochlore studies by Fourier Transform Infrared spectroscopy coupled with thermal analysis. Mineralogical Magazine, 60, 567–578.CrossRefGoogle Scholar
Putnis, A. (2002) Mineral replacement reactions: from macroscopic observations to microscopic mechanisms. Mineralogical Magazine, 66, 689–708.CrossRefGoogle Scholar
Putnis, C. and Mezger, K. (2004) A mechanism of mineral replacement: isotope tracing in the model s ystem KCl-KBr-H2O. Geochimica et Cosmochimica Acta, 68, 2839–2848.CrossRefGoogle Scholar
Pina, C.M., Enders, M. and Putnis, A. (2000) The composition of solid solutions crystallising from aqueous solutions: the influence of supersaturation and growth mechanisms. Chemical Geology, 168, 195–210.CrossRefGoogle Scholar
Reed, S.J.B. (1975) Electron Microprobe Analysis. Cambridge University Press, Cambridge, UK.Google Scholar
Ringwood, A.E., Kesson, S.E., Ware, N.G., Hibberson, W. and Major, A. (1979) Immobilization of high-level nuclear reactor wastes in SYNROC. Nature, 278, 219–223.CrossRefGoogle Scholar
Roberts, S.K., Bourcier, W.L. and Shaw, H.F. (2000) Aqueous dissolution kinetics of pyrochlore, zirconolite and brannerite at 25, 50 and 75°C. Radiochimica Acta, 88, 539–543.CrossRefGoogle Scholar
Rousseau, D.L., Bauman, R.P. and Porto, S.P.S. (1981) Normal mode determination in crystals. Journal of Raman Spectroscopy, 10, 253.CrossRefGoogle Scholar
Stoll, W. (1998) What are the options for disposition of excess weapons plutonium? Materials Research Bulletin, 23, 6–16.CrossRefGoogle Scholar
Subramanian, M.A., Aravamudan, G. and Subba Rao, G.V. (1983) Oxide pyrochlore – A review. Progress in Solid State Chemistry, 15, 55–143.CrossRefGoogle Scholar
Vandenborre, M.T. and Husson, E. (1983) Comparison of the force field in various pyrochlore families. I. The A2B2O7 oxides. Solid State Chemistry, 50, 362–371.CrossRefGoogle Scholar
Vandenborre, M.T. and Husson, E. (1984) Comparison of the force field in various pyrochlore families. II. Phases presenting structural defects. Solid State Chemistry, 53, 253–259.CrossRefGoogle Scholar
Voloshin, A.V., Men”shikov, Y.P., Pakhomovskii, Y.A. and Polezhaeva, L.I. (1981) Cesstibtantite, (Cs, Na)SbTa4O12 – a new mineral from granite pegmatites. Zapiskiv sesoyuznogo Mineralogicheskogo Obshchestva, 116, 345–351. (in Russian).Google Scholar
Wall, F., Williams, C.T. and Woolley, A.R. (1996) Pyrochlore from weathered carbonatite at Lueshe, Zaïre. Mineralogical Magazine, 60, 731–750.CrossRefGoogle Scholar
Weber, W.J., Catlow, C.R.A., Diaz de la Rubia, T., Hobbs, L.W., Kinoshita, C., Matzke, Hj., Motta, A.T., Nastasi, M., Salje, E.K.H., Vance, E.R. and Zinkle, S.J. (1998) Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium. Journal of Materials Research, 13, 1434–1484.CrossRefGoogle Scholar
Williams, C.T., Wall, F., Woolley, A.R. and Phillipo, S. (1997) Compositional variation in pyrochlore from the Bingo carbonatite, Zaire. Journal of African Earth Science, 25, 137–145.CrossRefGoogle Scholar
Xu, H., Wang, Y., Zhao, P., Bourcier, W.L., Van Konynenburg, R. and Shaw, H.F. (2004) Investigation of pyrochlore-based U-bearing ceramic nuclear waste: Uranium leaching test and TEM observation. Environmental Science and Technology, 38, 1480–1486.CrossRefGoogle ScholarPubMed
Zhang, Y., Hart, K.P., Bourcier, W.L., Day, R.A., Colella, M., Thomas, B., Aly, Z. and Jostsons, A. (2001) Kinetics of uranium release from Synroc phases. Journal of Nuclear Materials, 289, 254–262.CrossRefGoogle Scholar