Redox equilibrium of the UO22+/UO2+ couple in Li2MoO4–Na2MoO4 eutectic melt at 550 °C

Nagai, Takayuki; Uehara, Akihiro; Fujii, Toshiyuki; Sato, Nobuaki; Kofuji, Hirohide; Myochin, Munetaka; Yamana, Hideaki

doi:10.1016/j.jnucmat.2014.07.070

Cited by 1 publication

(3 citation statements)

References 26 publications

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“…6. The voltammograms recorded in the present study were quite different from obtained in Li 2 MoO 4 -Na 2 MoO 4 eutectic based melts containing added UO 2 , 22 where a fairly broad cathodic reduction wave was observed.…”

Section: Resultscontrasting

confidence: 96%

“…Therefore this phase was provisionally marked as "K 2 U(MoO 4 ) 3 ." Nagai et al 22 obtained somewhat similar results during the electrolysis of Li 2 MoO 4 -Na 2 MoO 4 eutectic based melts containing 22 Rising the temperature to 675 °C resulted in a mixture of MoO 2 and UO 2+x phases, but uranium oxide content was very low (so low, that in one run no UO 2+x was detected by XRD analysis, cf Figs. S7 and S8, and only chemical analysis showed uranium presence).…”

Section: Constant Current Electrolysis Of Uranium Containing Melts-mentioning

confidence: 69%

“…21 Cyclic voltammetry and electronic absorption spectroscopy measurements performed in Li 2 MoO 4 -Na 2 MoO 4 eutectic melt at 550 °C showed that uranium dioxide dissolved forming a mixture of UO 2 2+ and UO 2 + species. 22,23 Sparging the melt with oxygen resulted in oxidation of UO 2 + species to UO 2…”

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confidence: 99%

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Cathodic Processes in Uranium Containing Molybdate Melts

Volkovich

Smolenski

Рыжов

et al. 2023

J. Electrochem. Soc.

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Cathodic processes in Li2MoO4–K2MoO4–MoO3 UO2MoO4 and K2MoO4–MoO3 melts containing added UO2MoO4 were investigated at 550–800 oC using cyclic voltammetry, cathodic polarization and bulk electrolysis. Cathodic reduction of molybdate melts (not containing uranium) resulted in formation of molybdenum dioxide. Products of the cathodic reactions in the melts containing uranium molybdate predominantly consisted of crystalline uranium oxides (mostly UO2 and U4O9) and MoO2. Minor products formed included other uranium oxides (U3O8, U13O34), mixed uranium-molybdenum oxides (U1.5Mo10O32, Mo2UO8) and molybdates (provisionally attributed to K2U(MoO4)3). Effect of temperature, cathodic current density 0.05–1 A/cm2), excess MoO3 concentration (30–50 mol. %) on the composition of the cathodic reaction products were analyzed. Oxygen-to-uranium atomic ratio (oxygen coefficient) for primary uranium oxide phases was determined and varied from 1.963 to 2.161 for UO2±x and from 2.209 to 2.287 for U4O9±y. The effect of the electrolysis regime on the composition of the cathodic product was also considered. Constant-current and constant-potential electrolysis, as well pulsed-current, pulsed-potential and pulsed-reversed-current electrolysis were investigated with varying the parameters of alternating pulses (duration, current density or potential). Chemical and phase composition of the products produced by bulk electrolysis was fully characterized.

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Section: Resultscontrasting

confidence: 96%

Section: Constant Current Electrolysis Of Uranium Containing Melts-mentioning

confidence: 69%