Precipitation of Rare Earth Chlorides in a LiC-KCl Eutectic Molten Salt

LiCl-KCl 공융염 내에서 희토류염화물들의 침전

  • Cho, Yung-Zun (Advaced Fuel Cycle Development, Korea Atomic Energy Research Institute) ;
  • Yang, Hee-Chul (Advaced Fuel Cycle Development, Korea Atomic Energy Research Institute) ;
  • Eun, Hee-Chul (Advaced Fuel Cycle Development, Korea Atomic Energy Research Institute) ;
  • Kim, Eung-Ho (Advaced Fuel Cycle Development, Korea Atomic Energy Research Institute) ;
  • Kim, In-Tae (Advaced Fuel Cycle Development, Korea Atomic Energy Research Institute)
  • 조용준 (한국원자력연구원 선진핵연료주기개발단) ;
  • 양희철 (한국원자력연구원 선진핵연료주기개발단) ;
  • 은희철 (한국원자력연구원 선진핵연료주기개발단) ;
  • 김응호 (한국원자력연구원 선진핵연료주기개발단) ;
  • 김인태 (한국원자력연구원 선진핵연료주기개발단)
  • Received : 2007.05.22
  • Accepted : 2007.06.25
  • Published : 2007.08.10

Abstract

The precipitation reaction of some rare earth chlorides ($Ce/Nd/GdCl_3$) in a LiCl-KCl molten salt has been carried out by reaction with oxygen. Identification of rare earth precipitates by reaction with oxygen and effects of oxygen sparging time (max. 420 min) and molten salt temperature ($450{\sim}750^{\circ}C$) on conversion were investigated. In this study, regardless of the oxygen sparging time and the molten salt temperature, oxychlorides (REOCl) for $NdCl_3$ and $GdCl_3$, and an oxide ($REO_2$) for $CeCl_3$ are formed as a precipitate, which are identical with the estimation results of Gibbs free energy of reaction (${\Delta}G_r$). The conversion of rare-earth chlorides into insoluble precipitates was described by using a conversion ratio. The conversion ratio increased exponentially with the oxygen sparging time and finally showed asymptotic value, over 0.999 at $750^{\circ}C$ of the molten salt temperature and over 300 min of sparging time conditions. The conversion ratios were increased with the molten salt temperature. In case of $CeCl_3$, when the sparging time exceed 60 min, the values of the conversion ratio were nearly constant over 0.999 in all experimental temperature conditions.

Keywords

LiCl-KCl molten salt;oxygen sparging;rare earth element;precipitation

Acknowledgement

Supported by : 과학기술부

References

  1. Y. H. Kang, S. C. Hwang, J. B. Shim, E. H. Kim, and J. H. Yoo, J. Korean Ind. Eng. Chem., 14, 645 (2003)
  2. G. S. Picard, Y. E. Mottot, and B. L. Tremillon, in Proc. 5th International Symposium on Molten Salts, M. L. Saboungi, K. Johnson, D. S. Newman, and D. Inman eds., pp. 189-193, Pennington, NJ (1986)
  3. L. S. Fan, Gas-Liquid-Solid Fluidization Engineering, Butterworth Pub., MA (1989)
  4. Outokumpe web page : www.outokumpu.com/hsc
  5. J. Braunstein, G. Manabtov, and G. P. Smith, Advances in Molten Salt Chemistry, vol. 2, Plenum, New York (1973)
  6. D. M. Smith, M. P. Neu, E. Garcia, and V. R. Dole, J. Alloys Compounds, 319, 258 (2001) https://doi.org/10.1016/S0925-8388(01)00874-X
  7. Y. Katayama, R. Hagiwara, and Y. Ito, J. Electrochem. Soc., 142, 2174 (1995)
  8. C. C. Mcpheeters, R. D. Pierce, and T. P. Mulcahey, Progress in Nuclear Energy, 31, 175 (1997)
  9. E. Garcia, V. R. Dole, J. A. McNeese, and W. J. Griego, Los Alamos Science, 449 (2000)
  10. J. P. Ackerman, T. R. Johnson, L. S. H. Chow, E. L. Carls, W. H. Hannum, and J. J. Laidler, Progress in Nuclear Energy, 31, 141 (1997)