Везде

RAS Chemistry & Material ScienceРасплавы Melts

  • ISSN (Print) 0235-0106
  • ISSN (Online) 3034-5715

EVAPORATION OF LiCl-KCl-LaCl-CeCl-NdCl-UCl MOLTEN MIXTURES COMPONENTS AT REDUCED PRESSURES

You can
PII
10.31857/S0235010625030047-1
DOI
10.31857/S0235010625030047
Publication type
Article
Status
Published
Authors
A. B. Salyulev
  • Affiliation: Institute of High-Temperature Electrochemistry, Ural Branch of the Russian Academy of Sciences
Volume/ Edition
Volume / Issue number 3
Pages
218-236
Abstract
The present paper provides a brief review of the available data on the saturated vapor pressure and relative volatility of various individual chlorides (LiCl, KCl, NdCl, CeCl, LaCl, UCl) being present in the processes of pyrochemical reprocessing of spent nuclear fuel (SNF). It is shown that alkali metal chlorides are the most volatile. The volatility of rare earth metal and uranium trichlorides in the temperature range of 500-1000°C is 2-5 orders of magnitude lower. High-temperature vacuum distillation of components of molten chloride electrolytes based on the LiCl-KCl eutectic, placed in nickel boats containing uranium and rare earth metal trichlorides, was carried out under various conditions: temperature range 700-1000°C, exposure time 0.4-4 h, vacuum degree 2·10-2 Pa, UCl and REE trichlorides concentrations 0.25-1.7 mol. % and 0.13-0.7 mol. % (in total), respectively. The redistribution of salt components between the melt and vapor condensates was determined. It follows from the experimental data obtained in this study that alkali metal chlorides (LiCl, KCl) and REE chlorides (NdCl, CeCl, LaCl) can be fairly quickly (in 2-4 h) and completely distilled from a multicomponent salt electrolyte at the temperatures up to 850-900°С; their concentrations in the electrolyte by the end of distillation decrease by 2.5-4 orders of magnitude (for more volatile alkali chlorides - to a greater extent). Under the same conditions, the content of uranium compounds (in the form of UCl) can be reduced by no more than an order of magnitude, apparently due to incongruent (occurring with decomposition) evaporation of trichloride. Increasing the temperature above 900°С has little effect on the completeness of distillation for all components of molten mixtures. Conclusions have been made about the relative volatility of the components of molten salt mixtures (chlorides of alkali metals, REE and uranium). Optimal distillation modes have been selected. The dependences found may be useful for developing promising SNF processing schemes using salt distillation.
Keywords
отгонка испарение расплавленные смеси LiCl KCl LaCl CeCl NdCl UCl
Date of publication
12.05.2025
Year of publication
2025
Number of purchasers
0
Views
14

References

  1. 1. Park S.B., Cho D.W., Oh G.H., Lee J.H., Lee J.H., Hwang S.C., Kang Y.H., Lee H., Kim E.H., Park S.-W. Salt evaporation behaviors of uranium deposits from an electrorefiner // J. Radioanal. Nucl. Chem. 2010. 283. P. 171-176.
  2. 2. Jang J., Kim T., Park S., Kim G.-Y., Kim S., Lee S. Evaporation behavior of lithium, potassium, uranium and rare earth chlorides in pyroprocessing // J. Nucl. Mater. 2017. 497. P. 30-36.
  3. 3. Zaikov Yu.P., Shishkin V.Yu., Potapov A.M., Dedyukhin A.E., Kovrov V.A., Kholkina A.S., Volkovich V.A., Polovov I.B. Research and development of pyrochemical processing for the mixed nitride uranium-plutonium fuel // IOP Conf. Series: J. Physics. 2020. 1475. P. 012027.
  4. 4. Westphal B.R., Marsden K.C., Price J.C., Laug D.V. On the development of a distillation process for electrometallurgical treatment of irradiated spent nuclear fuel // Nucl. Eng. and Technol. 2008. 40. № 3. P. 163-174.
  5. 5. Yang H.-C., Eun H.-C., Kim I.-T. Study on the distillation rates of LiCl-KCl eutectic salt under different vacuum conditions // Vacuum. 2010. 84. P. 751-755.
  6. 6. Eun H.-C., Yang H.-C., Cho Y.-J., Park H.-S., Kim E.-H., Kim I.-T. Separation of pure LiCl-KCl eutectic salt from a mixture of LiCl-KCl eutectic salt and rare-earth precipitates by vacuum distillation // J. Nucl. Soc. and Technol. 2007. 44. P. 1295-1300.
  7. 7. Park H.P. Residual liquid behavior calculation for vacuum distillation of multi-component chloride system // J. Nucl. Fuel Cycle and Waste Technol. 2014. 12. P. 179-189.
  8. 8. Park B.H., Oh S.-C., Hur J.-M. Measurement of LiCl removal behavior from porous solids by vacuum evaporation // Vacuum. 2014. 109. P. 61-67.
  9. 9. Geng J., Luo Y., Fu H., Dou Q., He H., Ye G., Li Q. Temperature and pressure effect on evaporation behavior of chloride salts using low pressure distillation // Progress in Nucl. Energy. 2022. 147. P. 104212 (1-8).
  10. 10. Salyulev A.B., Shishkin A.V., Shishkin V.Yu., Zaikov Yu.P. Distillation of lithium chloride from the products of uranium dioxide metalization // Atomic Energy. 2019. 126. № 4. P. 226-229.
  11. 11. Salyulev A.B., Moskalenko N.I., Shishkin V.Yu., Zaikov Yu.P. Selective evaporation of the components of molten (LiCl-KCl)eut-BaCl2-SrCl2-NdCl3 mixtures at low pressures // Russ. Metallurgy (Metally). 2021. 2021. № 2. P. 151-158.
  12. 12. Salyulev A.B., Mullabaev A.R., Shishkin A.V., Kovrov V.A., Zaikov Yu.P., Mochalov Yu.S. Selective evaporation of components of molten LiCl-RbCl-CsCl-SrCl2-BaCl2 mixtures under reduced pressure // Russ. Metallurgy (Metally). 2024. 2024. № 4. P. 774-782.
  13. 13. Nikolaev A.Yu., Mullabaev A.R., Suzdaltsev A.V., Kovrov V.A., Kholkina A.S., Shishkin V.Yu., Zaikov Yu.P. Purification of alkali-metal chlorides by zone recrystallization for use in pyrochemical processing of spent nuclear fuel // Atomic Energy. 2022. 131. № 8. P. 195-201.
  14. 14. Лаптев Д.M. Физико-химические свойства хлоридов лантаноидов и их взаимодействие в системах LnCl3 - LnCl2 // Дис. … д-ра хим. наук. Новокузнецк, 1996. 394 с.
  15. 15. Ревзин Г.Е. Безводные хлориды редкоземельных элементов и скандия // Методы получения химических реактивов и препаратов. М.: ИРЕА, 1967. Вып. 16. С. 124-129.
  16. 16. Kochedykov V.A., Khokhlov V.A. Refractive indices and molar refractivities of molten rare-earth trichlorides and their mixtures with alkali chlorides // J. Chem. Eng. Data. 2017. 62. № 1. P. 44-51.
  17. 17. Roine A. HSC Chemistry 7.1 Thermochemical Database. Finland: Outokumpu Research Oy. 2014.
  18. 18. Миронов В.Л., Бурылев Б.П. Давление насыщенного пара индивидуальных хлоридов и их бинарных смесей // “Успехи термодинамики расплавов”: материалы Всесоюзного семинара. Краснодар: Краснодар. политехн. ин-т, 1976. С. 25-84.
  19. 19. Новиков Г.И., Гаврюченков Ф.Г. Комплексные галогениды в парах при высоких температурах // Успехи химии. 1967. 36. Вып. 3. С. 399-413.
  20. 20. Salyulev A.B. , Kudyakov V.Ya. Saturated vapor composition and volatility of uranium and some other metal tetrachlo-rides (ThCl4, HfCl4, ZrCl4, TiCl4) from their molten mixtures with alkali metal chlorides // Russ. Metallurgy (Metally). 2023. 2023. № 8. P. 986-992.
  21. 21. Суворов А.В. Термодинамическая химия парообразного состояния. Л.: Химия. 1970.
  22. 22. Шугуров С.М. Термическая устойчивость неорганических ассоциатов в газовой фазе // Дис. д-ра хим. наук. Санкт-Петербург, 2018.
  23. 23. Schäfer H. Gaseous chloride complexes with halogen bridges - homo-complexes and hetero-complexes // Angewandte Chemie, Intern. Edition. 1976. 15. № 12. P. 713-727.
  24. 24. Ярым-Агаев Н.Л. Термодинамические свойства и строение пара над расплавленными солями и их смесями // Ионные расплавы. Киев: Наукова думка. 1974. Вып. 1. С. 42-61.
  25. 25. Новиков Г.И., Баев А.К. К вопросу о летучести ацидокомплексных соединений в системах LnCl3 - KCl // Ж. неорг. химии. 1964. 9. Вып. 7. С. 1669-1675.
  26. 26. Murase K., Adachi G., Hashimoto M., Kudo H. Mass spectrometric investigation of the vapor over the LnCl3-KCl equimolar melt (Ln = Nd, Er) at high temperatures // Bull. Chem. Soc. Jpn. 1996. 69. P. 353-357.
  27. 27. Fukasawa K., Uehara A., Nagai T., Sato N., Fujii T., Yamana H. Thermodynamic properties of trivalent lanthanide and actinide ions in molten mixtures of LiCl and KCl. // J. Nucl. Mater. 2012. 424. P. 17-22.
  28. 28. Park S.B., Cho D.W., Woo M.S., Hwang S.C., Kang Y.H., Kim J.G., Lee H. Investigation of the evaporation of rare earth chlorides in a LiCl-KCl molten salt // J. Radioanal. Nucl. Chem. 2011. 287. P. 603-608.
  29. 29. Kwon S.W., Park S.W., Lee S.J. Effect of deposit on the evaporation rate of adhered salt in uranium dendrite // Science Technol. Nucl. Install. 2020. 2020. Article ID 8866234. 6 p.
  30. 30. Щукарев С.А., Василькова И.В., Ефимов А.И. О диспропорционировании трихлорида урана // Ж. неорг. химии. 1956. 1. № 12. С. 2652-2656.
  31. 31. Kovács A., Booij A.S., Cordfunke E.H.P., Kok-Scheele A., Konings R.J.M. On the fusion and vaporization behavior of UCl3 // J. Alloys and Compounds. 1996. 241. P. 95-97.
  32. 32. Choi S., Bae S.-E., Park T.-H. Electrochemical and spectroscopic monitoring of interactions of oxide ion with U (III) and Ln (III) (Ln = Nd, Ce, and La) in LiCl-KCl melts // J. Electrochem Soc. 2017. 164. P. H5068-H5073.
  33. 33. Jeon M.K., Yoo T.-S., Choi E.-Y., Hur J.-M. Quantitative calculations on the reoxidation behavior of oxide reduction system for pyroprocessing // J. Radioanal. Nucl. Chem. 2017. 313. P. 155-159.
QR
Translate

Индексирование

Scopus

Scopus

Scopus

Crossref

Scopus

Higher Attestation Commission

At the Ministry of Education and Science of the Russian Federation

Scopus

Scientific Electronic Library