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Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation; Preparation de bioxyde d'uranium par reduction electrochimique dans des solutions de carbonate d'ammonium et precipitation; Prigotovlenie dvuokisi urana metodom ehlektrokhimicheskogo vosstanovleniya v rastvore karbonata ammoniya s posleduyushchim osazhdeniem; Preparacion de dioxido de uranio por reduccion electroquimica en soluciones de carbonato amonico u precipitacion subsiguiente

Conference:

Abstract

Experiments in a small scale electrolysis cell on cathodic reduction of uranium (VI) to uranium (IV) show the possibility of an efficient way to obtain uranium (IV) in carbonate solutions. From this solution uranium (IV) hydrous oxide precipitates by merely raising the temperature. To obtain larger quantities of material needed for technological testing, a scale-up of the process was attempted. An electrolysis cell of hard PVC (polyvinylchloride) was constructed with a mercury pool cathode of approximately 2.5 dm{sup 2} and platinum anodes. The catholyte was separated from the anolyte by cationexchange membranes. The catholyte was circulated between two 50-1 reservoirs and streamed toward the vigorously stirred mercury cathode. The working potential of mercury was controlled against an Ag/AgCl/KC1 (sat.) reference electrode, the potential being held constant at -1.5 V. The current efficiency is approximately 90%; the power consumed for the reduction process is about 0.8 kWh/kg of uranium dioxide. After the electrolysis was completed the precipitation was initiated only by heating the deeply green clear solution up to 70 deg. C in a separate all-glass vessel of 60-1 volume. From 50, 1 of the catholyte solution 1 kg of a centrifuged product (containing about 20% of water) was obtained. The  More>>
Authors:
Pravdic, V.; Branica, M.; Pucar, Z. [1] 
  1. Department of Physical Chemistry, Rudjer Boskovic Institute, Zagreb, Yugoslavia (Serbia)
Publication Date:
Nov 15, 1963
Product Type:
Conference
Resource Relation:
Conference: Conference on New Nuclear Materials Technology, Including Non Metallic Fuel Elements, Prague (Czech Republic), 1-5 Jul 1963; Other Information: 4 figs., 1 tab., 6 refs.; Related Information: In: New Nuclear Materials Including Non Metallic Fuel Elements. Vol. I. Proceedings of the Conference on New Nuclear Materials Technology, Including Non Metallic Fuel Elements| 582 p.
Subject:
36 MATERIALS SCIENCE; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; AMMONIUM CARBONATES; ANODES; CATHODES; CENTRIFUGES; ELECTROCHEMISTRY; ELECTROLYSIS; HEATING; ION EXCHANGE; MERCURY; OXYGEN; PERFORMANCE TESTING; PRECIPITATION; SILVER CHLORIDES; SINTERING; SOLUTIONS; URANIUM; URANIUM DIOXIDE; X-RAY DIFFRACTION
OSTI ID:
22109647
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13R0430067292
Submitting Site:
INIS
Size:
page(s) 55-63
Announcement Date:
Jul 04, 2013

Conference:

Citation Formats

Pravdic, V., Branica, M., and Pucar, Z. Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation; Preparation de bioxyde d'uranium par reduction electrochimique dans des solutions de carbonate d'ammonium et precipitation; Prigotovlenie dvuokisi urana metodom ehlektrokhimicheskogo vosstanovleniya v rastvore karbonata ammoniya s posleduyushchim osazhdeniem; Preparacion de dioxido de uranio por reduccion electroquimica en soluciones de carbonato amonico u precipitacion subsiguiente. IAEA: N. p., 1963. Web.
Pravdic, V., Branica, M., & Pucar, Z. Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation; Preparation de bioxyde d'uranium par reduction electrochimique dans des solutions de carbonate d'ammonium et precipitation; Prigotovlenie dvuokisi urana metodom ehlektrokhimicheskogo vosstanovleniya v rastvore karbonata ammoniya s posleduyushchim osazhdeniem; Preparacion de dioxido de uranio por reduccion electroquimica en soluciones de carbonato amonico u precipitacion subsiguiente. IAEA.
Pravdic, V., Branica, M., and Pucar, Z. 1963. "Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation; Preparation de bioxyde d'uranium par reduction electrochimique dans des solutions de carbonate d'ammonium et precipitation; Prigotovlenie dvuokisi urana metodom ehlektrokhimicheskogo vosstanovleniya v rastvore karbonata ammoniya s posleduyushchim osazhdeniem; Preparacion de dioxido de uranio por reduccion electroquimica en soluciones de carbonato amonico u precipitacion subsiguiente." IAEA.
@misc{etde_22109647,
title = {Preparation of Uranium Dioxide by Electrochemical Reduction in Ammonium Carbonate Solutions and Subsequent Precipitation; Preparation de bioxyde d'uranium par reduction electrochimique dans des solutions de carbonate d'ammonium et precipitation; Prigotovlenie dvuokisi urana metodom ehlektrokhimicheskogo vosstanovleniya v rastvore karbonata ammoniya s posleduyushchim osazhdeniem; Preparacion de dioxido de uranio por reduccion electroquimica en soluciones de carbonato amonico u precipitacion subsiguiente}
author = {Pravdic, V., Branica, M., and Pucar, Z.}
abstractNote = {Experiments in a small scale electrolysis cell on cathodic reduction of uranium (VI) to uranium (IV) show the possibility of an efficient way to obtain uranium (IV) in carbonate solutions. From this solution uranium (IV) hydrous oxide precipitates by merely raising the temperature. To obtain larger quantities of material needed for technological testing, a scale-up of the process was attempted. An electrolysis cell of hard PVC (polyvinylchloride) was constructed with a mercury pool cathode of approximately 2.5 dm{sup 2} and platinum anodes. The catholyte was separated from the anolyte by cationexchange membranes. The catholyte was circulated between two 50-1 reservoirs and streamed toward the vigorously stirred mercury cathode. The working potential of mercury was controlled against an Ag/AgCl/KC1 (sat.) reference electrode, the potential being held constant at -1.5 V. The current efficiency is approximately 90%; the power consumed for the reduction process is about 0.8 kWh/kg of uranium dioxide. After the electrolysis was completed the precipitation was initiated only by heating the deeply green clear solution up to 70 deg. C in a separate all-glass vessel of 60-1 volume. From 50, 1 of the catholyte solution 1 kg of a centrifuged product (containing about 20% of water) was obtained. The coulometric analysis of the oxygen-uranium ratio always gave results in the range of 2.04 to 2.09. By the procedure described uranium (IV) hydrous oxide is selectively precipitated, and the oxygen-uranium ratio in the precipitate was found to be independent of the degree of completion of the reduction. The product was identified as the alpha phase of uranium dioxide by the X-ray powder diffraction. Experiments in sintering and characterization of uranium dioxide thus obtained for the ceramic nuclear fuel requirements are under way. (author) [French] Des experiences faites dans une petite cellule d'electrolyse sur la reduction cathodique d'uranium (VI) en uranium (IV) montrent qu'il est possible d'obtenir, avec un bon rendement, de l'uranium (IV) en solution carbonatee. Il suffit de chauffer la solution pour faire precipiter l'hydroxyde d'uranium (IV). Afin d'obtenir des matieres en quantites plus importantes, pour les essais technologiques, les auteurs ont fait une experience en plus grand. Ils ont construit une cellule d'electrolyse en chlorure de polyvynile dur, avec une cathode de mercure (environ 2,5dm{sup 2} ) et des anodes de platine. Le catholyte etait separe de l'anolyte par des membranes echangeuses de cations. Le catholyte circulait entre deux reservoirs de 50 1 et passait sur la cathode de mercure soumise a une agitation energique. Le potentiel du mercure etait controle par reference a une electrode temoin de Ag/AgCl/KCl (sat.), et maintenu constant a -1,5 V. Le rendement du courant etait d'environ 90% et la consommation d'energie, pour l'operation de reduction, d'environ 0,8 kWh/kg de bioxyde d'uranium. A la fin de l'electrolyse, on a provoque la precipitation par simple chauffage de la solution (limpide, d'un vert fonce) jusqu'a une temperature de 70 deg. C, dans un autre recipient tout en verre, de 60 1. Sur 50 1 de solution catholytique, on a obtenu 1 kg de produit centrifuge (contenant environ 20% d'eau). L'analyse coulombmetrique du rapport O/U a toujours donne des resultats compris entre 2,04 et 2,09. La methode decrite permet de faire precipiter l'hydroxyde d'uranium (IV) seul et le rapport O/U dans le precipite est independant du degre atteint par la reduction. En analysant la poudre par diffraction des rayons X, on a identifie le produit comme etant la phase alpha du bioxyde d'uranium. On procede maintenant a des experiences de frittage et a l'etude des caracteristiques du bioxyde d'uranium ainsi obtenu pour determiner s'il peut servir a la fabrication de combustible nucleaire ceramique. (author) [Spanish] Se intento ampliar la escala del proceso con el fin de obtener las cantidades de material que requieren los ensayos tecnologicos. Se construyo una celda electrolitica de cloruro de polivinilo duro con catodo de mercurio de aproximadamente 2,5dm{sup 2} de superficie y anodos de platino. El catolito estaba separado del anolito por membranas de intercambio cationico. El catolito se hizo circular entre dos depositos de 50 1 y se dirigio hacia el catodo de mercurio sometido a una agitacion energica. El potencial del mercurio se mantuvo constante en -1,5 V comprobandolo con un electrodo patron de Ag/AgCl/KCl (sat.). El rendimiento de la corriente es aproximadamente el 90% y la energia consumida para el proceso de reduccion esde unos 0,8 kWh/kg de dioxido de uranio. Una vez terminada la electrolisis, se inicio la precipitacion calentando simplemente a 70 deg. C la solucion limpida de color verde obscuro, en otro recipiente de vidrio de 60 1 de capacidad. A partir de 50 1 de solucion de catolito se obtuvo por centrifugacion 1 kg de producto (conteniendo alrededor de un 20% de agua). El analisis por culombimetria de la razon O/U dio resultados siempre comprendidos entre 2,04 y 2,09. El procedimiento descrito permite precipitar selectivamente el oxido hidratado de uranio (IV) observandose que la razon O/U en el precipitado es independiente del grado que haya alcanzado la reduccion. Analizando el polvo por difraccion de rayos X , se pudo identificar el producto como la fase alfa del dioxido de uranio. Se estan realizando experimentos de sinterizacion y caracterizacion del dioxido de uranio obtenido de esta manera a fin de comprobar en que medida responde a las especificaciones para combustibles nucleares ceramicos. (author) [Russian] Dlya polucheniya bol'shego kolichestva materiala, neobkhodimogo dlya tekhnologicheskikh ispytanij, sdelana popytka rasshirit' masshtab protsessa. Byl skonstruirovan ehlektrolizer iz tverdogo polivinil- khlorida s rtutnym katodom okolo 2,5dm''2 i platinovymi anodami. Katodnyj rastvor otdelyalsya ot anodnogo kationoobmennymi membranami. Katodnyj rastvor tsirkuliroval mezhdu dvumya 50-litrovymi rezervuarami i podavalsya k intensivno peremeshivaemomu rtutnomu katodu. Rabochij potentsial rtuti proveryalsya po ehlektrodu sravneniya Ag/AgCl/KCl (Sat.). Potentsial podderzhivalsya postoyannogo znacheniya - 1,5 vol't. Proizvoditel'nost' po toku byla okolo 90%, dlya protsessa vosstanovleniya potreblyaemaya ehnergiya sostavlyala okolo 0,8 kvt-chas/kg dvuokisi urana. Po okonchanii ehlektroliza osazhdenie initsiirovali tol'ko pri pomoshchi nagreva temnozelenogo, prozrachnogo rastvora do temperatury 70 deg. C v spetsial'nom steklyannom sosude ob''emom 60 1. Iz 50 1 katalicheskogo rastvora poluchili 1 kg tsentrifugirovannogo produkta (soderzhanie vody okolo 20%). Kulonometricheskij analiz otnosheniya O/U daval vsegda rezul'taty, lezhashchie v predelakh ot 2,04 do 2,0. Opisannym sposobom gidrookis' urana (IV) osazhdaetsya selektivno. Ustanovleno, chto otnoshenie O/U v osadke ne zavisit ot polnoty vosstanovleniya. Pri pomoshchi rentgenoskopii produkt identifitsirovan kak al'fa-faza dvuokisi urana. Opyty po spekaniyu i kharakteristike poluchennoj takim obrazom dvuokisi urana, prigodnoj dlya keramicheskogo yadernogo topliva, prodolzhayutsya. (author)}
place = {IAEA}
year = {1963}
month = {Nov}
}