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Stable isotope separation; Separations physicochimiques d'isotopes stables realisations et etudes de petites productions

Abstract

Pure deuterium has been separated from gaseous mixtures of hydrogen and deuterium by band displacement chromatography, using columns of palladium on a support. The best results were obtained with columns of Pd on sintered {alpha} alumina. With a column of this type, of total capacity about 2 liters, a preparative apparatus of low dead volume has been built which produces 1 liter of pure D{sub 2} from a 50 p. 100 D{sub 2}, 50 p. 100 100 H{sub 2} mixture in about 12 minutes. As a first approximation chromatography is likened theoretically to counter current fractionation, neglecting superficial resistance to the exchange. and also longitudinal diffusions. The number of theoretical plates required necessary for a certain enrichment of the gas phase is determined graphically or by calculation, enabling comparisons to be made between the efficiencies of columns containing different amounts of palladium. Thermal Diffusion: For the separation of hydrogen isotopes a thermal diffusion installation, made of stainless steel and entirely tele-commanded has been constructed. The separation cascade is made up of two identical pairs of hot wire columns. Each pair can work separately or they may be connected by a thermosyphon. The temperature of the hot wire is kept at  More>>
Authors:
Botter, F; Molinari, Ph; Dirian, G [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1964
Product Type:
Technical Report
Report Number:
CEA-R-2647
Resource Relation:
Other Information: 20 refs
Subject:
07 ISOTOPES AND RADIATION SOURCES; CHROMATOGRAPHY; ELECTROPHORESIS; HYDROGEN ISOTOPES; ISOTOPE SEPARATION; STABLE ISOTOPES; THERMAL DIFFUSION; TRITIUM; XENON
OSTI ID:
20668341
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R2647107042
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
24 pages
Announcement Date:
Dec 14, 2005

Citation Formats

Botter, F, Molinari, Ph, and Dirian, G. Stable isotope separation; Separations physicochimiques d'isotopes stables realisations et etudes de petites productions. France: N. p., 1964. Web.
Botter, F, Molinari, Ph, & Dirian, G. Stable isotope separation; Separations physicochimiques d'isotopes stables realisations et etudes de petites productions. France.
Botter, F, Molinari, Ph, and Dirian, G. 1964. "Stable isotope separation; Separations physicochimiques d'isotopes stables realisations et etudes de petites productions." France.
@misc{etde_20668341,
title = {Stable isotope separation; Separations physicochimiques d'isotopes stables realisations et etudes de petites productions}
author = {Botter, F, Molinari, Ph, and Dirian, G}
abstractNote = {Pure deuterium has been separated from gaseous mixtures of hydrogen and deuterium by band displacement chromatography, using columns of palladium on a support. The best results were obtained with columns of Pd on sintered {alpha} alumina. With a column of this type, of total capacity about 2 liters, a preparative apparatus of low dead volume has been built which produces 1 liter of pure D{sub 2} from a 50 p. 100 D{sub 2}, 50 p. 100 100 H{sub 2} mixture in about 12 minutes. As a first approximation chromatography is likened theoretically to counter current fractionation, neglecting superficial resistance to the exchange. and also longitudinal diffusions. The number of theoretical plates required necessary for a certain enrichment of the gas phase is determined graphically or by calculation, enabling comparisons to be made between the efficiencies of columns containing different amounts of palladium. Thermal Diffusion: For the separation of hydrogen isotopes a thermal diffusion installation, made of stainless steel and entirely tele-commanded has been constructed. The separation cascade is made up of two identical pairs of hot wire columns. Each pair can work separately or they may be connected by a thermosyphon. The temperature of the hot wire is kept at around 1000 deg C by direct current. With this installation, hydrogen samples with a deuterium content lower than o,5 ppm were obtained from a gas originally containing 32 ppm. It was thus possible to prepare tritium of 99,3 p. 100 concentration from gas with an initial content of 6 p. 100. For quantitative separation of xenon enriched five time in {sup 124}Xe by thermal diffusion, two identical cascades were constructed, each consisting of 5 columns, working in parallel and the two being connected by thermosyphon or by a capillary tube linked to a thermal gas oscillation. The central tungsten wire is heated to 1200 deg C. The columns are grouped like cluster of a heat exchanger, in shell of 30 cm diameter through which cooling water circulates. Studies are going forward to increase the separation factor of the cascade by using an auxiliary gas. Isotopic Exchange: A series of experiments has been performed to determine the isotopic separation factor between a lithium amalgam and an organic solvent containing a lithium salt. The various parameters which may enter into this exchange were studied: the influence of the type of solvent (the two solvents used were dimethylformamide and tetrahydrofurane), of the temperature, of the concentration and of the nature of the associated halogen. Solutions of Li metal and liquid NH{sub 3} were studied also. A number of tests were carried out to see whether there was a difference between the isotopic compositions of the Li present in the two liquid layers obtained by the dissolution of Li metal in ammonia. No difference was observed between the Li isotopic ratios in the two phases. This was also true in the case of a layer of of Li in liquid NH{sub 3} and a layer of Li I in a similar solvent. Electromigration: The method of counter current electro Migration in fused salts is a powerful isotopic enrichment technique. It can be used successfully to separate the isotopes of elements with strongly metallic character. In the case of alkalis, small quantities of isotopically pure {sup 7}Li have been obtained, while the enrichment factors obtained for potassium are of the order of 10. With regard to the alkaline earths, it has been possible to produce small quantities of calcium enriched 5 times in {sup 46}Ca. However considerable technological difficulties rise up in the way of production on a semi-industrial scale. (authors) [French] Nous avons effectue Ia separation de deuterium pur, a partir de melanges gazeux d'hydrogene et de deuterium, par chromatographie de deplacement de bande sur colonnes de palladium supporte. Les meilleures performances ont ete obtenues par des colonnes de Pd sur fritte d'alumine {alpha}. Avec une colonne de ce type, de capacite totale environ 2 litres, il a ete realise un appareil preparatif, de faible volume mort, permettant de produire 1 litre de D{sub 2} pur a partir des melange 50 p.100 D{sub 2}, 50 p.100 H{sub 2} en 12 minutes environ. Sur le plan theorique, en premiere approximation, nous assimilions la chromatographie a un fractionnement contre courant en negligeant resistance superficielle a l'echange ainsi que diffusions longitudinale et laterale. On etablit graphiquement ou par calcul, le nombre de plateaux theoriques necessires a un certain enrichissement de la phase gazeuse ce qui permet de comparer l'efficacite de colonnes qui different par leur masse palladiee. DIFFUSION THERMIQUE: Afin d'assurer une separation des isotopes de l'hydrogene, on a realise une installation de diffusion thermique construite en acier inoxydable et entierement telecommandee. La cascade de separation se compose de deux couples identiques de colonnes a fil central chaud. Chaque couple peut travailler isolement ou etre relie par thermosyphon. La temperature du fil chaud est de l'ordre de 1000 deg C entretenue par courant redresse. Avec cette installation, des echantillons d'hydrogene a la teneur isotopique en deuterium inferieure a 0,5 ppm. ont ete obtenus a partir d'un gaz initial a 32 ppm. Il a ainsi ete possible de preparer du tritium a la teneur de 99,3 p. 100 a partir d'un gaz d'une teneur initale de 6 p. 100. Pour la separation quantitative du Xenon enrichi cinq fois en {sup 124}Xe par thermodiffusion on a construit deux cascades identiques de 5 colonnes fonctionnant en parallele, reliees par thermosyphon ou par tube capillaire lie a un oscillateur thermique de gaz. Le fil central en tungstene fonctionne a 1200 deg C. Les colonnes sont groupees a la facon d'un faisceau tubulaire d'un echangeur de chaleur dans une virole de 30 cm de diametre ou circule l'eau de refroidissement. Des etudes sont en cours pour augmenter le facteur de separation de la cascade en utilisant un gaz auxiliaire. ECHANGE ISOTOPIQUE: Une serie d'experiences ont ete effectuees pour determiner le facteur de separation isotopique entre un amalgame de lithium et un solvant organique contenant un sel de lithium. Nous avons etudie Ies divers parametres qui peuvent intervenir dans cet echange: I'influence de la nature du solvant (les deux solvants utilises ont ete le dimethylformamide et le Tetrahydrofurane), influence de la temperature, influence de la concentration, influence de la nature de I'halogene associe. On a egalement etudie les solutions Li metal - NH{sub 3} Liquide, un certain nombre d'essais ont ete realises pour voir s'il y a une difference dans la composition isotopique du Li entre les deux couches liquides obtenues par dissolution du Li metal dans l'ammoniac. Aucune difference n'a ete constatee entre les rapports isotopiques du Li present dans les deux phases. II en etait de meme entre une couche de Li dans NH{sub 3} Liquide et une couche de Li dans un meme solvant. ELECTROMIGRATION: La methode d'electromigration a contre courant en sels fondus est une technique d'enrichissement isotopique puissante. Elle est applicable avec succes a la separation des isotopes d'elements a caractere metallique marque. Dans le cas des alcalins on a pu obtenir de petites quantites de {sup 7}Li isotopiquement pur. Pour le potassium les facteurs d'enrichissements obtenus sort de I'ordre de 10. En ce qui concerne Ies alcalino terreux la methode a permis d'obtenir de petites quantites de calcium enrichi 5 fois en {sup 46}Ca. Mais sa realisation a echelle semi-industrielle, se heurte a des difficultes technologiques considerables. (auteurs)}
place = {France}
year = {1964}
month = {Jul}
}