Extraction of Uranium(VI) from Nitric Acid Solution into Supercritical Carbon Dioxide Containing Tri-n-butylphosphate

Iso, Syuichi; Meguro, Yoshihiro; Yoshida, Zenko

doi:10.1246/cl.1995.365

Cited by 41 publications

(30 citation statements)

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“…Recent investigations into the utilisation of supercritical fluid carbon dioxide containing dissolved TBP indicate that effective extraction of actinides can be achieved without an organic phase diluent. 2,3) The efficiencies for the extraction of uranyl and thorium ions with TBP modified supercritical CO 2 were found to be comparable with those observed from the conventional solvent extraction with TBP dissolved in kerosene. 1) Advantages of supercritical fluid extraction include favourable mass transport properties and minimisation of waste solvent generation.…”

Section: Introductionmentioning

confidence: 58%

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Modelling of the Extraction of Uranium with Supercritical Carbon Dioxide.

Clifford¹,

Shu²,

Smart³

et al. 2001

J. Nucl. Sci. Technol.

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A model is presented for the analysis of the results of extraction of uranium in a flow system by supercritical fluid modified with tributylphosphate from a nitric acid matrix, in which the extraction is not limited by the solubility of the uranium species. The model used is that of diffusion out of a sphere into a medium in which the extracted uranium is infinitely dilute. Although not a completely accurate representation of the liquid-supercritical fluid system, the model is shown to be a reasonable representation and some conclusions discussed.

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Section: Introductionmentioning

confidence: 58%

“…Solutions of U(VI) were prepared by dissolving UO 2 (NO 3 ) 2 in 6 M HNO 3 . All other chemicals used were analytical reagent grade.…”

Section: Experiments 1 Apparatus and Reagentsmentioning

confidence: 99%

Modelling of the Extraction of Uranium with Supercritical Carbon Dioxide.

Clifford¹,

Shu²,

Smart³

et al. 2001

J. Nucl. Sci. Technol.

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“…Addition of such modifiers to supercritical CO 2 alters the polarity of the fluid phase, enhancing the extraction of metals. 5,6 Although the addition of polar modifiers can be effective for enhancing solubility, this reduces the environmental benefits of using carbon dioxide as a solvent.…”

Section: Concentrated Solution Of Contaminantmentioning

confidence: 99%

Micelle Formation and Surface Interactions in Supercritical CO2. Fundamental Studies for the Extraction of Actinides from Contaminated Surfaces.

McCleskey¹,

Birnbaum²

2001

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Executive Summary:This goal of this research was to build the fundamental understanding of microemulsion formation and mobility in supercritical CO 2 necessary to develop an innovative extraction system for selectively removing metals (actinides) from contaminated surfaces. Supercritical CO 2 has many advantages both for extraction from surfaces and minimization of the environmental impact of separation activities. The CO 2 solvent is an environmentally benign, inexpensive, radiologically and oxidatively stable extraction medium. We have studied reverse microemulsions that are comprised of nano-droplets of water (< 100 nm in diameter) suspended in CO 2 by a surfactant. The nano-droplets of water suspended in CO 2 take advantage of both the high solubility of metal ions in water and the high difussivity of CO 2 to penetrate pores that might be inaccessible to bulk water to aid in the complete decontamination of complex heterogeneous surfaces. The ability to readily control solubility by changing the pressure allows for facile separation of the surfactant and bound metal from the CO 2 solvent, enabling both concentration of the waste and recycle of the carbon dioxide. This extraction scheme is particularly attractive for remediation of heterogeneous waste in which small amounts of metal contaminants are dispersed throughout a large volume of solid waste. Typically, such extractions require an amount of water or solvent proportional to the volume of solid material.With microemulsions, CO 2 is effectively used as a diluent and the amount of water need only be proportional to the amount of metal to be extracted, making it possible to decontaminate grams of waste with µL of water. The stake for new selective separations is very high, as deconstruction and decontamination activities tend to produce large amounts of solid TRU waste. The disposal of TRU waste can exceed thousands of dollars/barrel, resulting in millions

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“…Supercritical fluid extraction (SFE) using an extractant-supercritical CO 2 mixture instead of an extractant-organic solvent mixture has recently been recognised to be promising as an advanced method for separation of metals from liquid samples or even from solid samples for the purpose of analytical pretreatment or hydrometallurgy. Hence, an increasing number of studies on the development of SFE of metals (Laintz and Tachikawa, 1994;Furton et al, 1995;Iso et al, 1995;Lin et al, 1995;Meguro et al, 1996;Toews et al, 1996;Wang and Wai, 1996;Smart et al, 1997) are available. One of several important advantages of SFE is that extraction efficiency and extraction selectivity can be enhanced by tuning the pressure and/or temperature.…”

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confidence: 99%

A novel equation of state (EOS) for prediction of solute solubility in supercritical carbon dioxide: Experimental determination and correlation

et al. 2009

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Solubility data of organophosphorous metal extractants in supercritical fluids (SCF) are crucial for designing metal extraction processes. We have developed a new equation of state (EOS) based on virial equation including an untypical parameter as BP/RT, reduced temperature and pressure for prediction of solute solubility in supercritical carbon dioxide (SC CO 2 ). Solubility experimental data (solubility of tributylphosphate in SC CO 2 ) were correlated with the two cubic equations of state (EOS) models, namely the Peng-Robinson EOS (PR-EOS) and the Soave-Redlich-Kwong EOS (SRK-EOS), together with two adjustable parameter van der Waals mixing and combining rules and our proposed EOS. The AARD of our EOS is significantly lower than that obtained from the other EOS models. The proposed EOS presented more accurate correlation for solubility data in SC CO 2 . It can be employed to speed up the process of SCF applications in industry.Les données de solubilité d'extractants de métaux organo-phosphorés dans des fluides supercritiques (FSC) sont cruciales pour concevoir des processus d'extraction des métaux. Nous avons développé une nouvelleéquation d'état (ÉÉ) basée sur uneéquation d'état du viriel comprenant un paramètre atypique tel que la température et la pression réduite pour la prédiction de la solubilité du soluté dans du dioxyde de carbone supercritique. Les données expérimentales de solubilité (solubilité du phosphate de tributyle dans CO 2 SC) ontété corrélées avec les deux modèles d'équations d'état cubiques, soit l'ÉÉ Peng-Robinson (ÉÉ-PR) et l'ÉÉ Soave-Redlich-Kwong (ÉÉ-SRK), avec deux paramètres ajustables, les règles de mélange et de combinaison van der Waals et notreÉÉ proposée. L'AARD de notreÉÉ est significativement plus faible que celui obtenuà partir des autres modèles d'ÉÉ. L'ÉÉ proposée présentait une corrélation plus exacte pour les données de solubilité dans le CO 2 SC. Elle peutêtre employée pour accélérer les processus des applications de FSC dans l'industrie.

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Extraction of Uranium(VI) from Nitric Acid Solution into Supercritical Carbon Dioxide Containing Tri-n-butylphosphate

Cited by 41 publications

References 4 publications

Modelling of the Extraction of Uranium with Supercritical Carbon Dioxide.

Modelling of the Extraction of Uranium with Supercritical Carbon Dioxide.

Micelle Formation and Surface Interactions in Supercritical CO2. Fundamental Studies for the Extraction of Actinides from Contaminated Surfaces.

A novel equation of state (EOS) for prediction of solute solubility in supercritical carbon dioxide: Experimental determination and correlation

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