title: In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.
abstract: Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.
authors.affiliation: Department of Rare Metals, Ural State Technical University-UPI, Ekaterinburg 62002, Russia. polovov@dpt.ustu.ru
authors.forename: Ilya B
authors.initials: IB
authors.lastname: Polovov
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Volkovich
authors.forename: John M
authors.initials: JM
authors.lastname: Charnock
authors.forename: Brett
authors.initials: B
authors.lastname: Kralj
authors.forename: Robert G
authors.initials: RG
authors.lastname: Lewin
authors.forename: Hajime
authors.initials: H
authors.lastname: Kinoshita
authors.forename: Iain
authors.initials: I
authors.lastname: May
authors.forename: Clint A
authors.initials: CA
authors.lastname: Sharrad