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Dissolution of compacted montmorillonite at hyperalkaline pH and 70°C: in situ VSI and ex situ AFM measurements

Published online by Cambridge University Press:  09 July 2018

H. Satoh ,
T. Ishii  and
H. Owada
H. Satoh*
Affiliation:
Mitsubishi Materials Corporation, Ibaraki, Japan
T. Ishii
Affiliation:
Radioactive Waste Management Funding and Research Center, Tokyo, Japan
H. Owada
Affiliation:
Radioactive Waste Management Funding and Research Center, Tokyo, Japan
*
*E-mail: hsatoh@mmc.co.jp
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Abstract

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In situ measurements were carried out to quantify montmorillonite dissolution rates at a compaction pressure ranging from 0.04 to 10.00 MPa and temperature of 70°C in 0.3 M NaOH solution (pH 12.1 at 70°C) using vertical scanning interferometry (VSI) and an auto-compaction cell. Ex situ measurements of the reacted samples using atomic force microscopy (AFM) were performed to quantify the ratio of edge surface area (ESA) to total surface area (TSA) (XESA = ESA/TSA). Accordingly, the actual ESA for the montmorillonite examined by in situ VSI could be estimated. The XESA value increases as a function of run duration or compaction pressure. At atmospheric pressure, XESA is approximately 0.0054 and converges to ∼0.0107 at 10 MPa, An expression that relates reactive surface area and montmorillonite compaction (XESA/XESA initial = kXESA, k: variable factor) is kXESA = 1.0 + 0.64628 P0.1527 where P is in MPa. Using the calculated XESA, dissolution rates from the in situ VSI measurements are obtained. The early dissolution (<1500 min) at less compaction pressure tends to show faster rates (>1.0 × 10-11 mol/m2/s) than that at higher compaction pressure. The rates after >1500 min are slower, with values of less than 3×6 10-12 mol/m2/s, but there is no significant dependency on the density in the range from 1.0 to 1.7 Mg/m3. These observed rates for compacted montmorillonite are two-orders of magnitude slower (2.63×10-13 mol/m2/s) than dissolution rates in the suspended state.

Keywords

montmorillonitedissolutioncompactionVSIAFMsurface areabentonite bufferalteration
Type
Research Article
Information
Clay Minerals , Volume 48 , Issue 2 , May 2013 , pp. 285 - 294
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2013 This is an Open Access article, distributed under the terms of the Creative Commons Attribution license. (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

References

Arvidson, R.S., Ertan, I.E., Amonette, J. E. & Lüttge, A. (2003) Rates of calcite dissolution obtained by vertical scanning interferometry. Geochimica et Cosmochimica Acta, 67, 1623–1634.10.1016/S0016-7037(02)01177-8CrossRefGoogle Scholar
Cama, J., Ganor, J., Ayora, C. & Lasaga, A.C. (2000) Smectite dissolution kinetics at 80°C and pH 8.8. Geochimica et Cosmochimica Acta, 64, 2701–2717.10.1016/S0016-7037(00)00378-1CrossRefGoogle Scholar
De Meer, S. & Spiers, C.J. (1999) On mechanisms and kinetics of creep by intergranular pressure solution. Pp. 345–366 in: Growth, Dissolution and Pattern Formation in Geosystems (Jamtveit, B. & Meakin, P., editors). Kluwer Academic Publishers.Google Scholar
Dijkstra, M., Hansen, J.-P., & Madden, P.A. (1997) Statistical model for the structure and gelation of smectite clay suspensions. Physical Review E, 55, 3044–3053.10.1103/PhysRevE.55.3044CrossRefGoogle Scholar
Giese, R.F., Costanzo, P.M. & van Oss, C.J. (1991) The surface free energies of talc and pyrophyllite. Physics and Chemistry of Minerals, 17, 611–616.10.1007/BF00203840CrossRefGoogle Scholar
Kuwahara, Y. (2006) In-situ AFM study of smectite dissolution under alkaline conditions at room temperature. American Mineralogist, 91, 1142–1149.10.2138/am.2006.2078CrossRefGoogle Scholar
Nakayama, S., Sakamoto, Y., Yamaguchi, T., Akai, M., Tanaka, T., Sato, T. & Iida, Y. (2004) Dissolution of montmorillonite in compacted bentonite by highly alkaline aqueous solutions and diffusivity of hydroxide ions. Applied Clay Science, 27, 53–65.10.1016/j.clay.2003.12.023CrossRefGoogle Scholar
Rozalén, M.L., Huertas, F.J., Brady, P.V., Cama, J., García-Palma, S. & Linares, J. (2008) Experimental study of the effect of pH on the kinetics of montmorillonite dissolution at 25°C. Geochimica et Cosmochimica Acta, 72, 4224–4253.10.1016/j.gca.2008.05.065CrossRefGoogle Scholar
Sato, T., Kuroda, M., Yokoyama, S., Tsutsui, M., Fukushi, K., Tanaka, T. & Makayama, S. (2004) Dissolution mechanism and kinetics of smectite under alkaline conditions. Proceedings of the Internations Workshop on Bentonite–Cement Interaction in Repository Environments, A3, 38–41.Google Scholar
Satoh, H., Nishimura, Y., Tsukamoto, K., Ueda, A., Kato, K. & Ueta, S. (2007) In-situ measurement of dissolution of anorthite in Na-Cl-OH solutions at 22°C using phase-shift interferometry. American Mineralogist, 92, 503–509.10.2138/am.2007.2153CrossRefGoogle Scholar
Van Driessche, A.E.S., García-Ruíz, J.M., Tsukamoto, K., Patiñ-Lopez, L.D. & Satoh, H. (2011) Ultraslow growth rates of giant gypsum crystals. PNAS, 108, 15721–15726.10.1073/pnas.1105233108CrossRefGoogle ScholarPubMed
Yokoyama, S., Kuroda, M. & Sato, T. (2005) Atomic force microscopy study of mintmorillonite dissolution under highly alkaline conditions. Clays and Clay Minerals, 53, 147–154.10.1346/CCMN.2005.0530204CrossRefGoogle Scholar