Effect of a Hydrothermal Reaction on the Expandibility, Layer Charge, and CEC of Smectite Clay

스멕타이트 점토의 팽창도, 층전하, 양이온 교환능에 대한 열수반응의 영향

  • Received : 2009.11.04
  • Accepted : 2010.08.12
  • Published : 2010.09.30

Abstract

In a HLW repository, the buffer is exposed to an elevated temperature due to a radioactive decay and geochemical conditions for a long time and such a hydrothermal condition may cause a significant loss of its barrier function. This study carried out hydrothermal tests with a domestic smectite clay to investigate the changes in the expandibility, layer charge, and cation exchange capacity of the smectite. When the temperature and potassium concentration in solution was increased for the hydrothermal treatments, the expandibility decreased, the layer charge negatively increased, and the CEC also decreased.

고준위폐기물처분장에서 완충재는 오랜 기간 동안 방사성핵종의 붕괴열과 여러가지 화학조건의 지하수에 노출되며, 이러한 열수조건은 완충재물질의 차수 및 핵종저지 방벽성능에 심각한 영향을 줄 수 있다. 본 연구에서는 국산 스멕타이트를 대상으로 열수실험을 수행하고, 열수반응에 의한 스멕타이트 점토의 팽창도, 층전하, 양이온교환능의 변화를 조사하였다. 열수실험 결과, 온도와 용액 중 칼륨농도를 증가시켰을 때, 스멕타이트의 팽창도는 감소하였고, 층전하는 더 큰 음전하를 가졌으며, 양이온교환능도 감소하였다.

Keywords

References

  1. C.H. Kang, J.E. Kuh, S.K. Kim., S.S. Kim, W.J. Cho, J.W. Choi, Y.M. Lee, J.O. Lee, Y.S. Hwang, "Highlevel Radwaste Disposal Technology Development: Geological Disposal System Development," KAERI/RR-2013/99, Korea Atomic Energy Research Institute (1999).
  2. A. Inoue, H. Minato, and M. Utada, "Mineralogical properties and occurrence of illite/montmorillonite mixed-layer minerals formed from Miocene volcanic glass in Waga-Omono district," Clay Sci., 5: 123-136 (1978).
  3. B. Velde, and A.M. Brusewitz, "Metasomatic and nonmetasomatic low-grade metamorphism of Ordovician metabentonites in Sweden," Geochim. Cosmochim. Acta, 46; 447-452 (1982). https://doi.org/10.1016/0016-7037(82)90235-6
  4. W.D. Keller, R.C. Reynolds, and A. Inoue, "Morphology of clay minerals in the smectite-to-illite conversion series by scanning electron microscopy," Clays Clay Miner., 34(2); 187-197 (1986). https://doi.org/10.1346/CCMN.1986.0340209
  5. A. Bouchet, D. Proust, A. Meunier, and D. Beaufort, "High-charge to low-charge smectite reaction in hydrothermal alteration processes," Clay Miner., 23; 133-146 (1988). https://doi.org/10.1180/claymin.1988.023.2.02
  6. A.M., Pytte and R.C. Reynolds, "The thermal transformation of smectite to illite," In thermal history of Sedimentary Basins, Editors Naeser N.D. and McCulloh T.H., Springer-Verlag New York, 133-140 (1989).
  7. B. Velde, and G. Vasseur, "Estimation of the diagenetic smectite to illite transformation in timetemperature space," Amer. Mineral. 77, 967-976 (1992).
  8. H. Wei, E. Roaldset, and M. Bjoroy, "Kinetics of smectite to illite conversion," EAPG 5th Conference, Stavanger (1993).
  9. D. Everl, "The reaction of montmorillonite to mixedlayer clay: the effect of interlayer alkali and alkalineearth cations," Geochim. Cosmochim. Acta, 42: 1-7 (1978). https://doi.org/10.1016/0016-7037(78)90210-7
  10. H.E. Roberson, and R.W. Lahann, "Smectite to illite conversion rates: effects of solution chemistry," Clays Clay Miner., 29: 129-135 (1981). https://doi.org/10.1346/CCMN.1981.0290207
  11. A. Inoue and M. Utada, "Further investigations of a conversion series of dioctahedral mica/smectite in the Shinzan hydrothermal alteration area, northeast Japan," Clays Clay Miner., 31: 401-412 (1983). https://doi.org/10.1346/CCMN.1983.0310601
  12. J.J. Howard, and D.M. Roy, "Development of layer charge and kinetics of experimental smectite alteration," Clays Clay Miner., 33, 81 (1985). https://doi.org/10.1346/CCMN.1985.0330201
  13. W.L. Huang, J.M. Longo, and D.R. Pevear, "An experimentally derived kinetic models for smectiteto-illite conversion and its use as a geothermometer," Clays and Clay Minerals 41, 162-177 (1993). https://doi.org/10.1346/CCMN.1993.0410205
  14. J. Cuadros, and J. Linares, "Experimental kinetics study of the smectite-to-illite transformation," Geochim. et Cos. Acta, Vol. 60, No. 3, 439 (1996). https://doi.org/10.1016/0016-7037(95)00407-6
  15. T. Sato, M. Kuroda, S. Yokoyama, M. Tsutsui, C. Pacau, C. Ringor, K. Fukushi, T. Tanaka, S. Nakayama, "Dissolution kinetics of smectite under alkaline conditions. International meeting: Clays in natural & engineering barriers for nuclear waste confinement," March 14-18, 2005, Tours, France (2005).
  16. A. Bauer, B. Lanson, E. Ferrage, K. Emmerich, H. Taubald, D. Schild, B. Velde, "The fate of smectite in KOH solution. American Mineralogist 91, 1313-1322 (2006). https://doi.org/10.2138/am.2006.2151
  17. K.S. Chun. K.S., W.J. Cho, J.O. Lee, S.S. Kim, M.J. Kang, "High-level waste disposal technology development: Engineered barrier development," KAERI/RR-1897/98, Korea Atomic Energy Research Institute (1998).
  18. A. Inoue, A. Bouchet, B. Velde, and A. Meunier, "Convenient technique for estimating smectite layer percentage in randomly interstratified illite/smectite minerals," Clays and Clay Minerals 37, 227-234 (1989). https://doi.org/10.1346/CCMN.1989.0370305
  19. R.C. Reynolds, "NEWMOD-A computer program for the calculation of basal diffraction intensities of mixed-layered clay minerals," 8 Brook Road, Hanover, New Hampshire (1985).
  20. A.C.D. Newman and G. Brown, "The chemical constitution of clays," In: Newman, A.C.D, Brown, G. (Eds.), Chemistry of Clays and Clay Minerals, Mineralogical Society, London, 1-128 (1987).
  21. R.F. Ylagan, S.P. Altaner, and A. Pozzuoli, "Reaction mechanisms of smectite illitization associated with hydrothermal alteration from Ponza Island, Italy," Clays and Clay Minerals 48, 610-631 (2000). https://doi.org/10.1346/CCMN.2000.0480603
  22. M.E. Sumner and W.P. Miller, "Methods of Soil Analysis. Part 3. Chemical Methods: Cation exchange capacity and exchange coefficients," Soil Science Society of America and American Society of Agronomy (2002).
  23. J. Hower, E.V. Eslinger, M.E. Hower, E.A. Perry, "Mechanism of burial metamorphism of argillaceous sediment," I. mineralogical and chemical evidence. Geological Society of America Bulletin 85, 827 (1976).
  24. J.R. Boles, S.G. Franks, "Clay diagenesis in Wilcox sandstones of southwest Texas: Implications of smectite diagenesis on sandstone cementation," Journal of Sedimentary Petrology 49, 55 (1979).
  25. D.W. Oscarson and H.B. Hume, "On the smectiteto-illite reaction," AECL-10842, Whiteshell Laboratories, Pinawa,Manitoba. (1993).
  26. Jae Owan Lee, Jeong Hwa Park, and Won Jin Cho, "Engineering-scale Validation Test for the T-H-M Behaviors of a HLW Disposal System," J. of the Korean Radioactive Waste Society, Vol.4(2), P.197-207 (2006).