Extraction of uranium from solid waste containing uranium and fluorine

Ohashi, Yusuke; Murashita, Shinji; Nomura, Mitsuo

doi:10.1016/j.mineng.2014.03.003

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…6 Uranium can be recovered from its solid waste as uranium peroxide by using H 2 O 2 . 7 The recent discovery of solid H 2 O 2 on the surface of Jupiter's moon Europa has renewed interest in the properties of solid H 2 O 2 . 8,9 However, H 2 O 2 has very limited stability due to its propensity to disproportionate exothermally into molecular oxygen and water, according to the following reaction:…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogen peroxide (H 2 O 2 ) is an environmentally friendly oxidant with a broad range of industrial applications, such as pulp and textile bleaching, tooth whitening, skin disinfection, and water treatment. − H 2 O 2 is a very attractive candidate as an antifouling agent in marine coatings, and it is an efficient oxidant in organic syntheses in the form of the urea–H 2 O 2 adduct . Uranium can be recovered from its solid waste as uranium peroxide by using H 2 O 2 . The recent discovery of solid H 2 O 2 on the surface of Jupiter’s moon Europa has renewed interest in the properties of solid H 2 O 2 . , However, H 2 O 2 has very limited stability due to its propensity to disproportionate exothermally into molecular oxygen and water, according to the following reaction: …”

Section: Introductionmentioning

confidence: 99%

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Hydrogen Peroxide Stability in Silica Hydrogels

Sudur

Pleskowicz

Orbey

2015

Ind. Eng. Chem. Res.

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Hydrogen peroxide (H 2 O 2 ) entrapment in silica hydrogels has potential to be used in various industrially important applications to increase H 2 O 2 stability. In this study, optimum conditions for hydrogel formation and H 2 O 2 stability were determined by varying the sodium content and initial H 2 O 2 concentration. Higher retention and better stability of H 2 O 2 were achieved with hydrogels at room temperature at low sodium concentration. Retention values of 89% were obtained with initial H 2 O 2 concentrations up to 10 wt %. H 2 O 2 decomposition in hydrogels followed a first-order reaction. Hydrogels were characterized by measuring their surface area, pore size, and pore size distribution by Brunauer−Emmett−Teller analysis and scanning electron microscopy. Mesoporous (3−24 nm) hydrogels with high surface area (1000−1400 m 2 /g) were obtained. In addition, the melting point of the entrapped H 2 O 2 -water mixture in the hydrogels was studied by low temperature differential scanning calorimetry.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hydrogen Peroxide Stability in Silica Hydrogels

Sudur

Pleskowicz

Orbey

2015

Ind. Eng. Chem. Res.

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“…The recovery of hexavalent uranium (U(VI)) from F − -containing nuclear wastewater is an important initiative for the reuse of nuclear fuel and the treatment of radioactive wastewater. [3][4][5][6] Traditionally, selective adsorption has been employed to remove U(VI) from F − -containing nuclear wastewater, [7][8][9][10][11][12][13][14][15][16] which suffers from sluggish kinetics and low efficiency due to the strong coordination bond between F − and U(VI). As such, adsorbents generally undergo a serious loss of capacity at a high concentration of interfering F − , which requires a pre-adsorption or diluting process to decrease the concentration of F − .…”

Section: Introductionmentioning

confidence: 99%

Achieving efficient uranium extraction by in situ ultrasonic texturization of commercial Fe powder

Zhu

Kang

et al. 2023

Environ. Sci.: Nano

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“…Sasahira et al (2007) mention an 'ash' that was formed during fluorination of UO 2 to UF 6 , while Ohashi, Recovery of uranium from nuclear conversion plant waste by M. Potgieter* † , J.C. Barry*, D.J. van der Westhuizen † , and H.M. Krieg † Recovery of uranium from nuclear conversion plant waste Murashita, and Nomura (2014) extracted uranium from UF 4 residue and NaF adsorbents originating from conversion activities. It thus became clear that this waste material is unique, in terms of its intrinsic variety in composition as well as the amounts and types of impurities present.…”

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confidence: 99%

“…For the envisioned SX process, provision should be made for the oxidation of insoluble U(IV) to soluble U(VI) during dissolution, possibly by means of the addition of an oxidizing agent. UF 4 can be completely solubilized by direct treatment with concentrated nitric acid (HNO 3 ) (Floreancig, 1983, Ohashi, Murashita, andNomura, 2014). Luk'yanchev and Nikolaev (1963) studied the dissolution of UF 4 in sulphuric (H 2 SO 4 ) and hydrochloric (HCl) acid, and found that the solubility of UF 4 increases with increasing HCl concentration, and reaches a maximum in H 2 SO 4 at approximately 3 M. Ohashi, Murashita, and Nomura (2014) used an oxidizing agent (H 2 O 2 ) during dissolution of UF 4 in H 2 SO 4 and HCl as part of a study on the extraction of uranium from fluorine-containing waste.…”

mentioning

confidence: 99%

Recovery of uranium from nuclear conversion plant waste

Potgieter

Westhuizen

Krieg

et al. 2017

J. South. Afr. Inst. Min. Metall.

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The ammonium diuranate (ADU) conversion process operated in South Africa from the 1970s was based on the direct conversion of ADU obtained from different mines (Ponelis, Slabber, and Zimmer, 1986;Ponelis, 1989). This approach differed from those of other countries operating conversion processes at that time in that the feed was not of nuclear grade. Since the ADU was sourced from various South African mines, the composition of the feed to the conversion plant at the Atomic Energy Corporation (AEC) varied. In addition, tail-end distillation of the uranium hexafluoride (UF 6 ) product was used, and as a result of the variability in the ADU a considerable proportion of unwanted elements or impurities, such as sodium (Na), potassium (K), and calcium (Ca), was present during the conversion process (Ponelis, Slabber, and Zimmer, 1986;Ponelis, 1989).Basically, the ADU conversion process entailed the conversion of ADU to uranium tetrafluoride (UF 4 ), which was then converted to uranium hexafluoride (UF 6 ) in a fluorine flame reactor (Ponelis, 1989). The final product, thermally stable UF 6 gas, was then filtered to remove any foreign particles. Thereafter, the UF 6 was frozen out and distilled before being fed to the enrichment plant. Due to the incomplete conversion of UF 4 to UF 6 in the fluorine flame reactor, a significant amount of solid waste rich in uranium was formed, which accumulated at the bottom of the reactor. The incomplete conversion could have been caused by various factors, including sintering due to the low melting point of UF 4 , inhomogeneous feed compositions, and the presence of various impurities. A study to determine the effect of alkali metal impurities on the conversion of UF 4 to UF 6 showed that the presence of these impurities had a significant effect on the sintering of UF 4 (Ponelis, 1989).Owing to the high uranium content, the unreacted material is a nuclear liability and needs to be processed to recover a product that can be re-used in possible future conversion activities while reducing the amount of waste that is currently stored in drums. A search of the literature was undertaken to determine whether similar waste exists elsewhere, and how it is handled. Sasahira et al. (2007) mention an 'ash' that was formed during fluorination of UO 2 to UF 6 , while Ohashi, Recovery of uranium from nuclear conversion plant waste by M. Potgieter* † , J.C. Barry*, D.J. van der Westhuizen † , and H.M. Krieg † The ammonium diuranate (ADU) conversion process that was operated at the Nuclear Energy Corporation of South Africa (Necsa) in the past generated a significant amount of waste containing high concentrations of uranium, which can be re-used if the uranium can be recovered in a useful form. To attain this objective, the composition of the waste material and the amounts of impurities present were determined, followed by an investigation into various methods of uranium dissolution. For dissolution, water as well as different acid types and concentrations were investigated, and the efficiency of eac...

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Extraction of uranium from solid waste containing uranium and fluorine

Cited by 11 publications

References 8 publications

Hydrogen Peroxide Stability in Silica Hydrogels

Hydrogen Peroxide Stability in Silica Hydrogels

Achieving efficient uranium extraction by in situ ultrasonic texturization of commercial Fe powder

Recovery of uranium from nuclear conversion plant waste

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