TY - JOUR

T1 - Reaction of Oxygen with Uranium (IV) Chloride in Fused Alkali Chlorides

AU - Volkovich, V.

AU - Ryzhov, A.

N1 - The research funding from the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program) is gratefully acknowledged.

PY - 2023/7

Y1 - 2023/7

N2 - Reaction of oxygen with solutions of uranium(IV) chloride in fused LiCl and three alkali chloride eutectic mixtures (LiCl–KCl, NaCl–KCl–CsCl, NaCl–CsCl) was investigated at 550–750 °C. Bubbling oxygen or oxygen-containing gas mixtures (O2–H2O, O2–Ar, O2–H2O–Ar) through LiCl–UCl4 melts resulted in significant precipitation of uranium (up to 87%) in the form of oxides and alkali uranates. Increasing mean radius of the solvent melt cations decreased the degree of uranium precipitation and uranyl chloride (soluble in the melt) became the main product of the reaction. High temperature spectroscopy measurements were employed to determine the kinetic parameters of the reaction in LiCl–KCl, NaCl–KCl–CsCl and NaCl–CsCl melts. Reaction rates, order, rate constants and activation energy values were estimated. Increasing temperature led to increased reaction rates but the effect of uranium chloride concentration depended on the cationic melt composition. Oxygen reacts with uranium(IV) containing melts much faster than with the melts containing rare earth chlorides and oxygen sparging can be implemented for separating uranium and rare earth fission products in pyrochemical reprocessing of spent nuclear fuels.

AB - Reaction of oxygen with solutions of uranium(IV) chloride in fused LiCl and three alkali chloride eutectic mixtures (LiCl–KCl, NaCl–KCl–CsCl, NaCl–CsCl) was investigated at 550–750 °C. Bubbling oxygen or oxygen-containing gas mixtures (O2–H2O, O2–Ar, O2–H2O–Ar) through LiCl–UCl4 melts resulted in significant precipitation of uranium (up to 87%) in the form of oxides and alkali uranates. Increasing mean radius of the solvent melt cations decreased the degree of uranium precipitation and uranyl chloride (soluble in the melt) became the main product of the reaction. High temperature spectroscopy measurements were employed to determine the kinetic parameters of the reaction in LiCl–KCl, NaCl–KCl–CsCl and NaCl–CsCl melts. Reaction rates, order, rate constants and activation energy values were estimated. Increasing temperature led to increased reaction rates but the effect of uranium chloride concentration depended on the cationic melt composition. Oxygen reacts with uranium(IV) containing melts much faster than with the melts containing rare earth chlorides and oxygen sparging can be implemented for separating uranium and rare earth fission products in pyrochemical reprocessing of spent nuclear fuels.

UR - https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=tsmetrics&SrcApp=tsm_test&DestApp=WOS_CPL&DestLinkType=FullRecord&KeyUT=001025135100001

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=85165226605

U2 - 10.1149/1945-7111/ace47f

DO - 10.1149/1945-7111/ace47f

M3 - Article

VL - 170

SP - 076504

JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

IS - 7

ER -