The Journal of Engineering Geology (지질공학)

The Korean Society of Engineering Geology (대한지질공학회)
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Homogenization Analysis of Problems related to Quartz Dissolution and Hydroxide Diffusion

석영광물의 용해 및 수산화 이온의 확산에 관한 균질화해석

  • Choi, Jung-Hae (Department of Urban Environmental Development, Okayama University) ;
  • Ichikawa, Yasuaki (Department of Urban Environmental Development, Okayama University)
  • 최정해 (일본 오카야마대학 대학원 환경학연구과) ;
  • Received : 2010.07.01
  • Accepted : 2010.07.28
  • Published : 2010.09.30
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Abstract

Time-dependent behavior similar to secondary deformation related to mineral dissolution is easily observed when performing a laboratory pressure experiment. In this research, to observe the dissolution of quartz found in bentonite used as buffer material for the geological disposal of high-level waste (HLW) under conditions of high pH, we calculated the diffusion of $OH^-$ ions and the behavior of quartz dissolution using the homogenization analysis method. The results reveal that the rate of quartz dissolution is proportional to the temperature and interlayer water thickness. In particular, in a high-pH environment, the reacted area (and therefore the dissolution rate) increases with decreasing interlayer water thickness.

광물의 용해현상과 밀접하게 관련된 암석의 시간의존성 변형과 파괴현상은 실내시험에서 비교적 용이하게 관찰된다. 본 연구에서는 고준위 방사성폐기물의 지하 처분장 건설시 완충제로 사용되어지는 벤토나이트에 많이 포함된 석영의 고 알칼리 환경 하에서의 용해 현상을 정량적으로 관찰하기 위해서 수산화 이온의 확산과 석영의 용해 문제를 균질화 해석법을 이용하여 평가하였다. 해석결과에 의하면 석영의 용해량은 주변 환경의 온도 및 층간수의 두께와 비례한다. 특히 고알칼리 환경 하에서는 층간수의 두께가 작아지면서 반응표면적이 커지게 되고 그 결과 용해 속도는 층간수의 두께가 작아질수록 커지는 결과를 나타내고 있다.

Keywords

References

  1. Berger, G., Cadore, E., Schott, J., Dove, P.M., 1994, Dissolution rate of quartz in lead and sodium electrolyte solution between 25 and $300^{\circ}$…: Effect of the nature of surface complexes and reaction affinity, Geochimica et Cosmochimica Acta., 58(2), 541-551. https://doi.org/10.1016/0016-7037(94)90487-1
  2. Brady, P.V. and Walther, J.V., 1990, Kinetics of quartz dissolution at low temperatures, Chemical Geology, 82, 253-264. https://doi.org/10.1016/0009-2541(90)90084-K
  3. Broekmann, M.A.T.M., 2004, Structure properties of quartz and their potential role for ASR, Materials Characterization, 53, 129-140. https://doi.org/10.1016/j.matchar.2004.08.010
  4. Cama, J., Metz, V., and Ganor, J., 2002, The effects of pH and temperature on kaolinite dissolution rate under acidic condition, Geochimica et Cosmochimica Acta, 66(22), 3923-3926.
  5. Dove, P.M., 1994, The dissolution kinetics of quartz in sodium chloride solutions at $25^{\circ}C$ to $300^{\circ}C$, American Journal of Science, 294, 665-712. https://doi.org/10.2475/ajs.294.6.665
  6. Ganor, J. and Lasaga, A.C., 1998, Simple mechanistic models for inhibition of a dissolution reaction, Geochimica et Cosmochimica Acta., 62(8), 1295-1306. https://doi.org/10.1016/S0016-7037(98)00036-2
  7. Ichikawa, Y., Kawamura, K., Fujii, N., and Theramast, N., 2002, Molecular dynamics and multiscale homogenization analysis of seepage/diffusion problem in bentonite clay, International Journal of Numerical Methods in Engineering, 54, 1717-1749. https://doi.org/10.1002/nme.488
  8. Ichikawa, Y., Kawamura K., Nakano, M., Kitayama, K., and Kawamura, H., 1999, Unified molecular dynamics and homogenization analysis for bentonite behavior: current results and the future possibility, Engineering Geology, 54, 21-31. https://doi.org/10.1016/S0013-7952(99)00058-7
  9. Ichikawa, Y., Kawamura K., Nakano, M., Kitayama, K., Seki, T., and Theramast, N., 2001, Seepage and consolidation of bentonite saturated with pure- or saltwater by the method of unified molecular dynamics and homogenization analysis, Engineering Geology, 60, 127-138. https://doi.org/10.1016/S0013-7952(00)00095-8
  10. Ichikawa, Y., Prayongphan, S., Kawamura, K., Chae, B.G., and Kitayama, K., 2005, Water flow and diffusion problem in bentonite: molecular simulation and homogenization analysis, In Coupled Thermo-Hydro-Mechanical-Chemical Processes in Geo-systems, Stephansson O et al. (eds). Elsevier: Amsterdam, 457-464.
  11. Knauss, K.G. and Wolery, T.J., 1988, The dissolution kinetics of quartz as a function of pH and time at $70^{\circ}C$, Geochimica et Cosmochimica Acta., 52, 43-53. https://doi.org/10.1016/0016-7037(88)90055-5
  12. Lasaga, A.C., 1995, Fundamental approaches in describing mineral dissolution and precipitation rate. In chemical weathering rates of silicate minerals, Mineralogical Society of America, 32, 23-86.
  13. Mitchell, K.J. and Soga, K., 1992, Fundamentals of soil behavior, Wiley: New york, 1-82.
  14. Xiao, Y. and Lasaga, A.C., 1996, Ab initio quantum mechanical studies of the kinetic and mechanisms of quartz dissolution: OH- catalysis, Geochimica et Cosmochimica Acta. 60(13), 2283-2295. https://doi.org/10.1016/0016-7037(96)00101-9