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Mondino, A. V.; Wilkinson, M. V.; Manzini, A. C.

doi:10.1023/a:1006771232672

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…The current plant-scale process, known as PUREX, involves dissolving UO 2 in hot 50% HNO 3 , which results in a solution with about 400 g of uranium per liter. Spent fuel reprocessing strategies that emphasize alkaline conditions have also been studied in the USA, Japan, Korea, and Russia as an alternative to acid-based dissolution. − Aqueous solutions rich in carbonate and peroxide are used to dissolve UO 2 fuel that yields solutions with about 100 g of uranium per liter, which is generally lower than ideal . Studies focused on dissolution of UO 2 in alkaline, peroxide-rich solutions have not reported the formation of uranyl peroxide cage clusters, although these studies do not report characterization methods that would have revealed the presence of clusters in solution …”

Section: Introductionmentioning

confidence: 99%

Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

et al. 2018

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Solid UO dissolution and uranium speciation in aqueous solutions that promote formation of uranyl peroxide macroanions was examined, with a focus on the role of alkali metals. UO powders were dissolved in solutions containing XOH (X = Li, Na, K) and 30% HO. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements of solutions revealed linear trends of uranium versus alkali concentration in solutions resulting from oxidative dissolution of UO, with X:U molar ratios of 1.0, showing that alkali availability determines the U concentrations in solution. The maximum U concentration in solution was 4.20 × 10 parts per million (ppm), which is comparable to concentrations attained by dissolving UO in boiling nitric acid, and was achieved by lithium hydroxide promoted dissolution. Raman spectroscopy and electrospray ionization mass spectrometry (ESI-MS) of solutions indicate that dissolution is accompanied by the formation of various uranyl peroxide cluster species, the identity of which is alkali concentration dependent, revealing remarkably complex speciation at high concentrations of base.

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Section: Introductionmentioning

confidence: 99%

Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

et al. 2018

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“…An obvious alternative to acidic UO 2 dissolution is the use of alkaline solutions. For many years, hydroxide has been used in the presence of an oxidant, such as NaOCl or H 2 O 2 , to dissolve uranium metal and its alloys. − These two oxidants are especially applicable for studying UO 2 dissolution as it pertains to long-term geological disposal because they are the radiolysis products of brine and water, respectively. Several studies have been reported using NaOCl 23 and H 2 O 2 , in alkaline media to determine both corrosion of the UO 2 surface , and dissolution kinetics .…”

Section: Introductionmentioning

confidence: 99%

Kinetic Study of the Oxidative Dissolution of UO₂ in Aqueous Carbonate Media

Peper

Brodnax

Field

et al. 2004

Ind. Eng. Chem. Res.

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The oxidative dissolution of uranium(IV) dioxide powder at room temperature in aqueous carbonate media has been investigated. Kinetic studies evaluating the efficacy of various oxidants, including K2S2O8, NaOCl, and H2O2, for dissolving UO2 in alkaline solution have been performed, with H2O2 exhibiting the most rapid initial dissolution at 0.1 M oxidant concentrations. This result is due in part to the ability of peroxide to act as both an oxidant and a ligand under alkaline conditions. A spectrophotometric titration was used to confirm peroxide coordination to the U(VI) metal center. The disappearance of characteristic absorbance maxima associated with UO2(CO3)3 4- (e.g., 448.5 nm) and a subsequent change in solution coloration upon titration with hydrogen peroxide indicated a change in speciation. Optimization of the hydrogen peroxide concentration indicated that the initial rate of uranium oxidation increased with increasing peroxide concentration, with a maximum reaction rate estimated at about 0.9 M peroxide. In addition, the effects of both the carbonate countercation and the carbonate concentration were also studied. It was determined that for 40 mg UO2 0.5 M Na2CO3 was the most propitious choice, exhibiting both a high initial dissolution rate and the highest UO2 dissolution capacity among the systems studied.

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Comparative extraction efficiencies of tri-n-butyl phosphate and N,N-dihexyloctanamide for uranium recovery using supercritical CO2

Kanekar

Pathak

Mohapatra

et al. 2009

J Radioanal Nucl Chem

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Cited by 4 publications

References 3 publications

Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

Kinetic Study of the Oxidative Dissolution of UO₂ in Aqueous Carbonate Media

Comparative extraction efficiencies of tri-n-butyl phosphate and N,N-dihexyloctanamide for uranium recovery using supercritical CO2

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Untitled

Cited by 4 publications

References 3 publications

Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

Kinetic Study of the Oxidative Dissolution of UO2 in Aqueous Carbonate Media

Comparative extraction efficiencies of tri-n-butyl phosphate and N,N-dihexyloctanamide for uranium recovery using supercritical CO2

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Kinetic Study of the Oxidative Dissolution of UO₂ in Aqueous Carbonate Media