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Anode processes on Pt and ceramic anodes in chloride and oxide-chloride melts

  • Mullabaev, A.R. (Institute of High-Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences) ;
  • Kovrov, V.A. (Institute of High-Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences) ;
  • Kholkina, A.S. (Institute of High-Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences) ;
  • Zaikov, Yu.P. (Institute of High-Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences)
  • Received : 2021.06.07
  • Accepted : 2021.08.29
  • Published : 2022.03.25

Abstract

Platinum anodes are widely used for metal oxides reduction in LiCl-Li2O, however high-cost and low-corrosion resistance hinder their implementation. NiO-Li2O ceramics is an alternative corrosion resistant anode material. Anode processes on platinum and NiO-Li2O ceramics were studied in (80 mol.%) LiCl-(20mol.%)KCl and (80 mol.%)LiCl-(20 mol.%)KCl-Li2O melts by cyclic voltammetry, potentiostatic and galvanostatic electrolysis. Experiments performed in the LiCl-KCl melt without Li2O illustrate that a Pt anode dissolution causes the Pt2+ ions formation at 3.14 V and 550℃ and at 3.04 V and 650℃. A two-stage Pt oxidation was observed in the melts with the Li2O at 2.40 ÷ 2.43 V, which resulted in the Li2PtO3 formation. Oxygen current efficiency of the Pt anode at 2.8 V and 650℃ reached about 96%. The anode process on the NiO-Li2O electrode in the LiCl-KCl melt without Li2O proceeds at the potentials more positive than 3.1 V and results in the electrochemical decomposition of ceramic electrode to NiO and O2. Oxygen current efficiency on NiO-Li2O is close to 100%. The NiO-Li2O ceramic anode demonstrated good electrochemical characteristics during the galvanostatic electrolysis at 0.25 A/cm2 for 35 h and may be successfully used for pyrochemical treating of spent nuclear fuel.

Keywords

Acknowledgement

The present research was partially performed within the Proryv (Breakthrough) project of State Atomic Energy Corporation Rosatom.

References

  1. A. Zhitkov, A. Potapov, K. Karimov, V. Shishkin, A. Dedyukhin, Y. Zaykov, Interaction between UN and CdCl2 in molten LiCl-KCl eutectic. I. Experiment at 773 K, Nucl. Eng. Technol. 52 (2020) 123-134, https://doi.org/10.1016/j.net.2019.07.006.
  2. Frederic Lantelme Henri Groult, Molten Salts Chemistry, Elsevier, 2013.
  3. J.-M. Hur, J.-S. Cha, E.-Y. Choi, Can carbon Be an anode for electrochemical reduction in a LiCl-Li2O molten salt, ECS Electrochemistry Letters 3 (2014), https://doi.org/10.1149/2.0071410eel. E5-E7.
  4. S.-W. Kim, M.K. Jeon, H.W. Kang, Sang-Kwon Lee, E.-Y. Choi, W. Park, S.-S. Hong, S.-Ch. Oh, J.-M. Hur, Carbon anode with repeatable use of LiCl molten salt for electrolytic reduction in pyroprocessing, J. Radioanal. Nucl. Chem. 310 (2016) 463-467, https://doi.org/10.1007/s10967-016-4786-5.
  5. S.P. Ray, in: P.A. Warrendale (Ed.), Inert Anodes for Hall Cell, Light Metals, TMS-AIME, 1986, pp. 287-298.
  6. Huayi Yina, Lili Gaoa, Hua Zhua, Xuhui Maoa, Fuxing Gana, Dihua Wang, On the development of metallic inert anode for molten CaCl2-CaO System, Electrochim. Acta 56 (2011) 3296-3302, https://doi.org/10.1016/j.electacta.2011.01.026.
  7. V. Chapman, B.J. Welch, M. Skyllas-Kazacos, Anodic behaviour of oxidized NiFe alloys in cryolite-alumina melts, Electrochim. Acta 56 (2011) 1227-1238, https://doi.org/10.1016/j.electacta.2010.10.095.
  8. Y. Sakamura, M. Kurata, T. Inoue, Electrochemical reduction of UO2 in molten CaCl2 or LiCl, J. Electrochem. Soc. (2006) D31-D39, https://doi.org/10.1149/1.2160430.
  9. B.H. Park, I.W. Lee, C.-S. Seo, Electrolytic reduc-tion behavior of U3O8 in a molten LiCl-Li2O salt, Chem. Eng. Sci. 63 (2008) 3485-3492, https://doi.org/10.1016/j.ces.2008.04.021.
  10. Yoshiharu Sakamura, Effect of alkali and alkaline-earth chloride addition on electrolytic reduction of UO2 in LiCl salt bath, J. Nucl. Mater. 412 (2011) 177-183, https://doi.org/10.1016/j.jnucmat.2011.02.055.
  11. S.D. Herrmann, P.K. Tripathy, S.M. Frank, J.A. King, Comparative study of monolithic platinum and iridium as oxygen-evolving anodes during the electrolytic reduction of uranium oxide in a molten LiCl-Li2O electrolyte, J. Appl. Electrochem. 49 (2019) 379-388, https://doi.org/10.1007/s10800-019-01287-1.
  12. S.-W. Kim, S.-K. Lee, H.W. Kang, E.-Y. Choi, W. Park, S.-S. Hong, S.-C. Oh, J.-M.Hur Electrochemical properties of noble metal anodes for electrolytic reduction of uranium oxide, J. Radioanal. Nucl. Chem. 311 (2017) 809-814, https://doi.org/10.1007/s10967-016-5107-8.
  13. S.M. Jeong, H.-S. Shin, S.-H. Cho, J.-M. Hur, H.S. Lee, Electrochemical behavior of a platinum anode for reduction of uranium oxide in a LiCl molten salt, Electrochim. Acta 54 (2009) 6335-6340, https://doi.org/10.1016/j.electacta.2009.05.080.
  14. T. Biju Joseph, N. Sanil, L. Shakila, K.S. Mohan-das, K. Nagarajan, A cyclic voltammetry study of the electrochemical behavior of platinum in oxide-ion rich LiCl melts, Electrochim. Acta 139 (2014) 394-400, https://doi.org/10.1016/j.electacta.2009.05.080.
  15. Y. Sakamura, M. Iizuka, Applicability of nickel ferrite anode to electrolytic reduction of metal oxides in LiCl-Li2O melt at 923 K, Electrochim. Acta 189 (2016) 74-82, https://doi.org/10.1016/j.electacta.2015.12.086.
  16. A.B. Dubovtsev, Yu.P. Zaikov, I.V. Murygin, L.E. Ivanovskij, Behaviour of the oxide anodes at the electrolysis chloride-oxide melts. 1. Interaction oxide electrodes with melt, Rasplavy 1 (1992) 35-40.
  17. A.B. Dubovtsev, Yu.P. Zaikov, I.V. Murygin, L.E. Ivanovskij, Behaviour of the oxide anodes at the electrolysis chloride-oxide melts. 2. Investigation of anodic process on the ceramic electrode, Rasplavy 1 (1992) 41-48.
  18. S.-W. Kim, H.W. Kang, M.K. Jeon, S.-K. Lee, E.-Y. Choi, W. Park, S.-S. Hong, S.-Ch. Oh, J.-M. Hur chemical stability of conductive ceramic anodes in LiCl-Li2O molten salt for electrolytic reduction in pyroprocessing, Nuclear Engineering and Technology 48 (2016) 997-1001, https://doi.org/10.1016/j.net.2016.03.002.
  19. Yu.P. Zajkov, A. B Dubovtsev, V.P. Batukhtin, A.P. Khramov, L.E. Ivanovskij, Electrolysis with oxide anodes in chloride-oxide melt, Rasplavy 2 (1995) 41-46.
  20. A.B. Dubovtsev, Yu.P. Zajkov, L.I. Ivanovskij, Equilibrium potentials of oxide electrode in CaCl2-CaO melt, Rasplavy 1 (1994) 48-53.
  21. A. Mullabaev, O. Tkacheva, V. Shishkin, V. Kovrov, Y. Zaikov, L. Sukhanov, Y. Mochalov, Properties of the LiCl-KCl-Li2O system as operating medium for pyro-chemical reprocessing of spent nuclear fuel, J. Nucl. Mater. 500 (2018) 235-241, https://doi.org/10.1016/j.jnucmat.2018.01.004.
  22. P.A. Arkhipov, A.N. Baraboshkin, Z.I. Valeev, Z.S. Martemyanova, Molybdenum electrodeposition from low-melting chloride baths, Soviet Electrochemistry, 1388-1392 (1990) 26.
  23. Yu.R. Khalimullina, Yu.P. Zaikov, P.A. Arkhipov, V.V. Ashikhin, G.V. Skopov, A.S. Kholkina, N.G. Molchanova, Thermodynamic characteristics of the Pb-Bi alloys in the KCl-PbCl2 melt, Russ. J. Non-Ferrous Metals 52 (2011) 197-204, https://doi.org/10.3103/S1067821211030126.
  24. A. Roine, HSC Chemistry® [Software], Outotec, Pori 2018. Software available at, www.outotec.com/HSC.
  25. E.-Y. Choi, J.W. Lee, J.J. Park, J.-M. Hur, J.-K. Kim, K.Y. Jung, S.M. Jeong, Electrochemical reduction behavior of a highly porous SIMFUEL particle in a LiCl molten salt, Chem. Eng. J. 207-208 (2012) 514-520, https://doi.org/10.1016/j.cej.2012.06.161.
  26. R. Kasuya, T. Miki, Y. Tai, Preparation of Li2PtO3 and its dissolution properties in hydrochloric acid, J. Ceram. Soc. Jpn. 121 (2013) 261-264, https://doi.org/10.2109/jcersj2.121.261, 2013.
  27. A. Suzdaltsev, A. Khramov, V. Kovrov, O. Limanovskaya, V. Nekrasov, Y. Zaikov, Voltammetric and chronopotentiometric study of nonstationary processes at the oxygen-evolving anodes in KF-NaF-AlF3-Al2O3 melt, Mater. Sci. Forum 844 (2016) 19-26. https://doi.org/10.4028/www.scientific.net/MSF.844.19.
  28. A.B. Salyulev, A.V. Shishkin, V. Yu. Shishkin, Yu.P. Zaikov, Distillation of lithium chloride from the products of uranium dioxide metalization, Atom. Energy 126 (2019) 226-229, https://doi.org/10.1007/s10512-019-00541-1.
  29. Yu.P. Zaikov, A.P. Khramov, L.E. Ivanovskii, Prospects for use of oxide composites as nonsacrificial anodes in high-temperature electrolysis of oxidehalide salt melts, Russ. J. Electrochem. 33 (1997) 1306-1310.