EP0100744B1 - Process for extracting uranium from phosphoric acids using alkylpyrophosphoric acids - Google Patents

Process for extracting uranium from phosphoric acids using alkylpyrophosphoric acids Download PDF

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EP0100744B1
EP0100744B1 EP83420127A EP83420127A EP0100744B1 EP 0100744 B1 EP0100744 B1 EP 0100744B1 EP 83420127 A EP83420127 A EP 83420127A EP 83420127 A EP83420127 A EP 83420127A EP 0100744 B1 EP0100744 B1 EP 0100744B1
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uranium
process according
extraction
extraction process
acid
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EP0100744A1 (en
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Antoine Floreancig
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Uranium Pechiney
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Uranium Pechiney
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
    • C22B60/02—Obtaining thorium, uranium, or other actinides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B60/00—Obtaining metals of atomic number 87 or higher, i.e. radioactive metals
    • C22B60/02—Obtaining thorium, uranium, or other actinides
    • C22B60/0204—Obtaining thorium, uranium, or other actinides obtaining uranium
    • C22B60/0217—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes
    • C22B60/0252—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes treatment or purification of solutions or of liquors or of slurries
    • C22B60/026—Obtaining thorium, uranium, or other actinides obtaining uranium by wet processes treatment or purification of solutions or of liquors or of slurries liquid-liquid extraction with or without dissolution in organic solvents

Definitions

  • the invention relates to an improved process for extracting by means of an agent, consisting of alkylpyrophosphoric acids, uranium present in phosphoric acid solutions, process which makes it possible to conserve over time the extraction power of said agent in limiting its degradation.
  • alkylpyrophosphoric acids as uranium extraction agent, used in a form dissolved in an organic diluent, such as that petroleum cut, kerosene, etc., the most commonly used extraction agent being alkylpyrophosphoric acid obtained by reaction of P 2 0 5 with octanol 2.
  • recovering the uranium contained in phosphoric acid at a rate of 90 to 200 milligrams of uranium oxide U 3 0 8 per liter consists first of all in contacting the solution of phosphoric acid with the extraction agent most commonly constituted by octylpyrophosphoric acid in solution in kerosene, the extraction of uranium being carried out against the current in a group of mixing and sedimentation tanks cascade.
  • the organic phase containing in solution the octylpyrophosphoric acid loaded with uranium, separated from the phosphoric acid solution, is treated by contact using hydrofluoric acid, giving fluoride d uranium (UF 4 ) and desuranic octylpyrophosphoric acid.
  • alkylpyrophosphoric acids as uranium extraction agent, and in particular octylpyrophosphoric acid, lies in the fact of their strong extracting power, even when they are used in organic solution very diluted, allowing them to extract, with a very good yield, the uranium present, even in very small quantity, in solutions of phosphoric acids.
  • 2423545 describes a process for extracting uranium from phosphoric acid solutions, the extracting agent of which is a pyrophosphoric acid diester such as dicaproyl pyrophosphate or dioctyl pyrophosphate, a process according to which the hydrolysis of said extracting agent would be greatly reduced, while the re-extraction of the uranium present in the organic phase is carried out by means of an alkaline solution and no longer by l hydrofluoric acid.
  • the extracting agent of which is a pyrophosphoric acid diester such as dicaproyl pyrophosphate or dioctyl pyrophosphate
  • the licensee thanks to her research, found and developed an improved process for extracting uranium contained in solutions of phosphoric acids, means of an extraction agent chosen from the group of alkylpyrophosphoric acids which makes it possible to avoid their degradation by acid hydrolysis, while retaining their extracting power.
  • the process according to the invention for the extraction of uranium contained in phosphoric acid solutions by means of an extraction agent consisting of an alkylpyrophosphoric acid, which consists in bringing the mineral phase of phosphoric acid and an organic phase containing the extraction agent by creating an emulsion is characterized in that, in an extraction unit comprising n stages in cascade with n> 1, for each extraction stage, the emulsion is produced during a first step by simultaneously subjecting the two phases for a time T, to an intense mechanical shearing action corresponding to a shear coefficient of at least 5000 s -1 in order to increase the contact surfaces between these two phases, then said emulsion during a second step is suddenly broken in a time T z , the total time required for the completion of the two steps being at most 20 minutes.
  • the extraction unit has a number of stages n of between 2 and 20.
  • this shear coefficient is chosen in the interval 5000 s -1 to 50,000 s -1 , but preferably in the interval 10,000 s -1 to 25,000 s -1 .
  • the total time required to carry out the two stages according to the invention is preferably at most equal to 10 minutes for an extraction stage.
  • the times T, and T of execution of the two stages can vary within wide limits, their ratio T, / T 2 being able to be chosen within the limits 1/100 to 5/1 and preferably within limits 1 / 25 to 2/1.
  • the emulsion between the two organic and mineral phases is produced by any means known to those skilled in the art, making it possible to quickly and vigorously obtain the finest emulsion possible, in order to multiply the surfaces of contact and obtain a very high extraction yield.
  • the rapid separation of the organic and mineral phases can be obtained by physical means using any known means allowing rapid rupture of said emulsion.
  • the extracting agent, entrained by the desuranic phosphoric acid can be recovered by a physical separation of centrifugation for example and joined to the recycled extraction agent after re-extraction of the uranium .
  • the uranium extracting agent is chosen from the well-known group of alkylpyrophosphoric acids, the alkyl radical of which is a carbon chain corresponding to the C 7 to C 13 alcohols obtained by oxo synthesis , such as for example octanol 2, ethylhexanol, cancanol.
  • the preparation of alkylpyrophosphoric acid can be carried out in a known manner by adding P 2 O 5 to the abovementioned alcohol, used alone or as a mixture with a hydrocarbon.
  • the temperature for preparing alkylpyrophosphoric acid is generally between 30 ° C and 80 ° C, but preferably between 30 ° C and 40 ° C.
  • the uranium extracting agent is generally dissolved in an aliphatic and / or aromatic hydrocarbon, such as kerosene for example.
  • the mixture thus formed constitutes the organic phase of extraction of the uranium, which contains from 5 to 100 g / l but preferably from 20 to 50 g / l of alkylpyrophosphoric acid.
  • the phosphoric acid solutions resulting from the attack on phosphate ores generally contain from 30 to 200 milligrams of uranium per liter, this uranium being partly in the form U IV and for the other in the form U VI.
  • the uranium VI is then reduced to uranium IV by the treatment of phosphoric acid solutions with iron, in the form of powder when the reduction treatment is carried out in a reactor or also in the form of scrap metal when the reduction treatment takes place in a column.
  • the phosphoric acid solutions containing suspended solids are subjected to a separation operation, before being brought into contact with the extractant in solution in an aliphatic hydrocarbon. and / or aromatic.
  • the two mineral and organic phases to be extracted and extracting are then brought into intimate contact in the form of a fine emulsion which is quickly broken in order to separate the organic phase loaded with uranium from the mineral phase with deuranied acid.
  • the organic phase loaded with uranium is then treated with an aqueous hydrofluoric acid solution, this solution containing 10 to 20%, but preferably 14 to 18% by weight of free HF.
  • the temperature at which the uranium is re-extracted by hydrofluoric acid is between 0 ° C and 60 ° C but preferably between 10 ° C and 30 ° C, temperature at which the degradation of the alkylpyrophosphoric acid remains low (less than 2%).
  • the uranium then precipitates in the form of UF 4 , which is separated from the liquid medium by any means chosen from those known to those skilled in the art.
  • the desuranized alkylpyrophosphoric acid is then recycled directly to the extraction of the uranium contained in the solutions of phosphoric acids after possible recharging with new alkylpyrophosphoric acid, while the solutions of desuranic phosphoric acids are themselves subjected to centrifugation to recover the mechanically driven extractant.
  • This example illustrates the method of extracting uranium according to the invention, using alkylpyrophosphoric acids compared to the extraction method most commonly used in the processes belonging to the prior art.
  • This acid is reduced either by powdered iron in a stirred tank for tests 1 to 4, or in a column by plate iron for tests 5 and 6.
  • the reduced phosphoric acid contains Fe II and Fe III in an Fe II / Fe III ratio between 5 and 5.3.
  • the phosphoric acid is treated with the extracting agent in solution in kerosene at a rate of 30 g / l.
  • the reduced phosphoric acid flow rate was 200 l / h while that of the extractant solution was 20 l / h.
  • the desuranized solvent was recycled to extraction after adding a fraction of an hour of the extractant.
  • Test No. 1 which illustrates the prior art, was carried out in an industrial installation whose extraction unit consisted of a battery of 4 mixer-settlers - extraction unit in which the cumulative times T 1 and T 2 for 4 stages as defined in the method according to the invention, is equal to 14 hours.
  • Test No. 2 illustrating the invention was carried out in an industrial installation, the extraction unit of which consisted of a 4-stage multi-stage centrifugal extractor, rotating at the speed of 2800 rpm, a unit in which the accumulation residence times T, and T z for 4 stages was less than two minutes.
  • Test No. 3 illustrating the prior art, differs from test No. 1 in the nature of the extractant which in this case was a solution of ethylhexylpyrophosphoric acid.
  • Test No. 4 illustrating the invention, differs from test No. 2 in the nature of the extractant which was ethylhexylpyrophosphoric acid.
  • Test No. 5 illustrating the prior art, differs from test No. 1 only in the mode of reduction of phosphoric acid (on platelets in column).
  • Test N ° 6 illustrating the invention, differs from test N ° 2 by the mode of reduction of phosphoric acid and by the constitution of the extraction unit which included four single stage centrifugal extractors in battery - unit in which the cumulative residence times T, and T 2 was less than two minutes.
  • This example illustrates the method of extracting uranium according to the invention, using alkylpyrophosphoric acids, compared to the extraction method most commonly used in methods belonging to the prior art.
  • the phosphoric acid treated had the following composition:
  • Test No. 7 which illustrates the prior art, was carried out like test 1, in a battery of 4 mixer-settlers.
  • Test No. 8 which illustrates the invention, was carried out like test 2, but using a battery comprising 3 single-stage centrifugal extractors.

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  • Manufacture And Refinement Of Metals (AREA)

Description

L'invention concerne un procédé amélioré d'extraction au moyen d'un agent, constitué par les acides alkylpyrophosphoriques, de l'uranium présent dans lessolutions d'acide phosphorique, procédé permettant de conserver dans le temps le pouvoir d'extraction audit agent en limitant sa dégradation.The invention relates to an improved process for extracting by means of an agent, consisting of alkylpyrophosphoric acids, uranium present in phosphoric acid solutions, process which makes it possible to conserve over time the extraction power of said agent in limiting its degradation.

Depuis longtemps déjà et comme l'atteste le grand nombre de publications dans ce domaine, de nombreuses recherches ont été effectuées pour trouver le procédé d'extraction de l'uranium présent dans les solutions d'acide phosphorique, qui soit le mieux adapté et le plus performant.For a long time now and as evidenced by the large number of publications in this field, much research has been carried out to find the method of extraction of uranium present in phosphoric acid solutions, which is the most suitable and the more efficient.

Dans le groupe des procédés d'extraction actuellement connu, l'homme de l'art a retenu celui qui fait usage des acides alkylpyrophosphoriques comme agent d'extraction de l'uranium, mis en oeuvre sous une forme solubilisée dans un diluant organique, tel que coupe pétrolière, kérosène, etc., l'agent d'extraction le plus usité étant l'acide alkylpyrophosphorique obtenu par réaction de P205 sur l'octanol 2.In the group of extraction processes currently known, those skilled in the art have chosen the one which uses alkylpyrophosphoric acids as uranium extraction agent, used in a form dissolved in an organic diluent, such as that petroleum cut, kerosene, etc., the most commonly used extraction agent being alkylpyrophosphoric acid obtained by reaction of P 2 0 5 with octanol 2.

Parmi les nombreuses recherches en ce domaine, il est possible de citer les travaux de R.S. Long, matérialisés par le compte rendu des Conférences de Genève du 8 au 20 août 1955, volume VIII, page 524, sur la «récupération de l'uranium des phosphates par extraction au moyen de solvants», et le brevet américain N° 2866680 concernant un procédé d'extraction de l'uranium en solution acide au moyen d'un solvant constitué par un acide alkylpyrophosphorique.Among the many researches in this field, it is possible to cite the work of RS Long, materialized by the report of the Geneva Conferences from August 8 to 20, 1955, volume VIII, page 524, on the “recovery of uranium from phosphates by extraction using solvents ”, and US Pat. No. 2,866,680 concerning a process for extracting uranium in acid solution using a solvent consisting of an alkylpyrophosphoric acid.

Selon les travaux de R.S. Long, la récupération de l'uranium contenu dans l'acide phosphorique à raison de 90 à 200 milligrammes d'oxyde d'uranium U308 par litre, consiste tout d'abord à mettre en contact la solution d'acide phosphorique avec l'agent d'extraction constitué le plus couramment par l'acide octylpyrophosphorique en solution dans du kérosène, l'extraction de l'uranium se faisant à contre-courant dans un groupe de cuves de mélange et de sédimentation en cascade. Puis, dès la sortie de la dernière cuve de sédimentation, la phase organique contenant en solution l'acide octylpyrophosphorique chargé en uranium, séparée de la solution d'acide phosphorique, est traitée par contact au moyen d'acide fluorhydrique en donnant le fluorure d'uranium (UF4) et l'acide octylpyrophosphorique désuranié.According to the work of RS Long, recovering the uranium contained in phosphoric acid at a rate of 90 to 200 milligrams of uranium oxide U 3 0 8 per liter, consists first of all in contacting the solution of phosphoric acid with the extraction agent most commonly constituted by octylpyrophosphoric acid in solution in kerosene, the extraction of uranium being carried out against the current in a group of mixing and sedimentation tanks cascade. Then, as soon as it leaves the last sedimentation tank, the organic phase containing in solution the octylpyrophosphoric acid loaded with uranium, separated from the phosphoric acid solution, is treated by contact using hydrofluoric acid, giving fluoride d uranium (UF 4 ) and desuranic octylpyrophosphoric acid.

Il est de notoriété que l'intérêt d'utiliser les acides alkylpyrophosphoriques comme agent d'extraction de l'uranium, et en particulier l'acide octylpyrophosphorique, réside dans le fait de leur fort pouvoir extractant, même quand ils sont utilisés en solution organique très diluée, leur permettant d'extraire, avec un très bon rendement, l'uranium présent, même en très faible quantité, dans les solutions d'acides phosphoriques.It is well known that the advantage of using alkylpyrophosphoric acids as uranium extraction agent, and in particular octylpyrophosphoric acid, lies in the fact of their strong extracting power, even when they are used in organic solution very diluted, allowing them to extract, with a very good yield, the uranium present, even in very small quantity, in solutions of phosphoric acids.

Cependant, lorsque l'extraction de l'uranium des solutions d'acides phosphoriques est réalisée à l'échelle industrielle au moyen de l'acide octylpyrophosphorique par exemple, il est connu que l'agent d'extraction de l'uranium, dès lors qu'il a été débarrassé de l'uranium et qu'il est recyclé à l'extraction, ne possède plus le pouvoir d'extraction initial, c'est-à-dire que le coefficient d'extraction dudit agent est abaissé comparativement à sa valeur d'origine. Et il devient alors nécessaire, soit de faire l'appoint en acide alkylpyrophosphorique pour ramener à un niveau raisonnable le coefficient d'extraction, soit même de remplacer la totalité de l'agent d'extraction usagé par un agent neuf.However, when the extraction of uranium from phosphoric acid solutions is carried out on an industrial scale by means of octylpyrophosphoric acid for example, it is known that the uranium extracting agent, therefore that it has been freed from uranium and that it is recycled for extraction, no longer has the initial extraction power, that is to say that the extraction coefficient of said agent is lowered compared to its original value. And it then becomes necessary, either to add alkylpyrophosphoric acid to bring the extraction coefficient to a reasonable level, or even to replace all of the used extraction agent with a new agent.

De nombreuses tentatives ont alors été faites pour conserver aux acides alkylpyrophosphoriques et en particulier à l'acide octylpyrophosphorique leur coefficient d'extraction initial, lorsqu'ils sont mis en oeuvre pour extraire l'uranium dessolu- tions d'acides phosphoriques. Parmi les moyens proposés pour sauvegarder le pouvoir extractant dudit agent, il a été suggéré de pratiquer la réextraction de l'uranium contenu dans l'acide alkyl- phosphorique utilisé, non plus au moyen de l'acide fluorhydrique mais par une solution alcaline, puisqu'il était admis que l'acide alkylpyrophosphorique chargé en uranium subissait une hydrolyse de la part de l'acide fluorhydrique, agent de réextraction habituel, en donnant des esters d'acide phosphorique. Mais il a également été proposé d'autres moyens tel celui qui consiste en l'ajout d'un tiers corps, par exemple l'octanol 2 ou le tributylphos- phate, à l'agent d'extraction constitué par un acide alkylpyrophosphorique ou encore d'employer comme agent d'extraction de l'uranium, d'autres acides alkylpyrophosphoriques, offrant une sensibilité amoindrie à l'hydrolyse acide, ou bien à abaisser la température d'extraction, etc. C'est dans cet esprit que le brevet français N° 2423545 décrit un procédé d'extraction de l'uranium de solutions d'acide phosphorique dont l'agent d'extraction est un diester de l'acide pyrophosphorique tel que le pyrophosphate de dicaproyle ou encore le pyrophosphate de dioctyle, procédé selon lequel l'hydrolyse dudit agent d'extraction serait fortement diminuée, tandis que la réextraction de l'uranium présent dans la phase organique s'effectue au moyen d'une solution alcaline et non plus par l'intermédiaire de l'acide fluorhydrique.Numerous attempts have then been made to preserve alkylpyrophosphoric acids and in particular octylpyrophosphoric acid their initial extraction coefficient, when they are used to extract uranium from phosphoric acid solutions. Among the means proposed to safeguard the extracting power of said agent, it has been suggested to practice the re-extraction of the uranium contained in the alkylphosphoric acid used, no longer by means of hydrofluoric acid but by an alkaline solution, since 'It was recognized that the alkylpyrophosphoric acid loaded with uranium underwent hydrolysis on the part of hydrofluoric acid, the usual re-extraction agent, giving phosphoric acid esters. However, other means have also been proposed such as that which consists in adding a third body, for example octanol 2 or tributylphosphate, to the extraction agent constituted by an alkylpyrophosphoric acid or else to use as an extracting agent uranium, other alkylpyrophosphoric acids, offering a reduced sensitivity to acid hydrolysis, or to lower the extraction temperature, etc. It is in this spirit that French patent No. 2423545 describes a process for extracting uranium from phosphoric acid solutions, the extracting agent of which is a pyrophosphoric acid diester such as dicaproyl pyrophosphate or dioctyl pyrophosphate, a process according to which the hydrolysis of said extracting agent would be greatly reduced, while the re-extraction of the uranium present in the organic phase is carried out by means of an alkaline solution and no longer by l hydrofluoric acid.

Toutefois, malgré les nombreuses solutions proposées, force est de constater que l'extraction en continu de l'uranium de valence IV, à l'échelle industrielle, au moyen d'un acide alkylpyrophosphorique recyclé après la réextraction de l'uranium, exige à chaque cycle un appoint important en acide alkylpyrophosphorique neuf, cet appoint pouvant atteindre souvent plus de la moitié de l'agent extractant utilisé pour un cycle.However, despite the many solutions proposed, it is clear that the continuous extraction of valence IV uranium, on an industrial scale, using an alkylpyrophosphoric acid recycled after the re-extraction of uranium, requires each cycle a significant addition of new alkylpyrophosphoric acid, this makeup often reaching more than half of the extractant used for a cycle.

Devant la quasi-impossibilité sinon de maintenir, tout au moins de limiter la perte du pouvoir extractant des acides alkylpyrophosphoriques au contact des solutions d'acides phosphoriques contenant l'uranium, il a même été proposé dans le brevet américain N° 4293529 de dégrader complètement par chauffage l'agent extractant à chaque cycle, puis, après oxydation de U IV en U VI, de réextraire l'uranium par une solution d'acide phosphorique.Faced with the quasi-impossibility if not to maintain, at least to limit the loss of the extracting power of alkylpyrophosphoric acids in contact with solutions of phosphoric acids containing uranium, it has even been proposed in the American patent N ° 4293529 by heating the extracting agent at each cycle, then, after oxidation of U IV to U VI, to re-extract the uranium with a solution of phosphoric acid.

Poursuivant ses recherches en ce domaine, en vue d'améliorer le procédé d'extraction de l'uranium à partir des solutions d'acides phosphoriques au moyen d'acides alkylpyrophosphoriques, la titulaire a pu observer que les pertes en agent d'extraction étaient la conséquence non seulement de l'action de l'acide fluorhydrique lors de la réextraction de l'uranium, mais aussi de l'action de l'acide phosphorique (et de ses impuretés) lors de son contact avec l'agent d'extraction, et ce d'une manière d'autant plus importante et critique que le temps de contact est plus long.Continuing his research in this area, in with a view to improving the process for extracting uranium from phosphoric acid solutions using alkylpyrophosphoric acids, the licensee was able to observe that the losses of extractant were the consequence not only of the action hydrofluoric acid during the re-extraction of uranium, but also the action of phosphoric acid (and its impurities) during its contact with the extracting agent, and this in a 'The more important and critical the longer the contact time.

Dès lors, forte des inconvénients précités et des phénomènes qu'elle a pu étudier, la titulaire grâce à ses recherches, a trouvé et mis au point un procédé amélioré d'extraction de l'uranium contenu dans les solutions d'acides phosphoriques, au moyen d'un agent d'extraction choisi dans le groupe des acides alkylpyrophosphoriques qui permet d'éviter leur dégradation par hydrolyse acide, tout en leur conservant leur pouvoir extractant.Therefore, with the above-mentioned drawbacks and the phenomena it was able to study, the licensee, thanks to her research, found and developed an improved process for extracting uranium contained in solutions of phosphoric acids, means of an extraction agent chosen from the group of alkylpyrophosphoric acids which makes it possible to avoid their degradation by acid hydrolysis, while retaining their extracting power.

Le procédé selon l'invention de l'extraction de l'uranium contenu dans les solutions d'acides phosphoriques au moyen d'un agent d'extraction constitué par un acide alkylpyrophosphorique, qui consiste à mettre en contact sous agitation la phase minérale d'acide phosphorique et une phase organique contenant l'agent d'extraction en créant une émulsion, se caractérise en ce que, dans une unité d'extraction comprenant n étages en cascade avec n > 1, pour chaque étage d'extraction, l'émulsion est produite lors d'une première étape en soumettant simultanément les deux phases pendant un temps T, à une action mécanique de cisaillement intense correspondant à un coefficient de cisaillement d'au moins 5000 s-1 dans le but de multiplier les surfaces de contact entre ces deux phases, puis ladite émulsion lors d'une deuxième étape est brutalement cassée en un temps Tz, le cumul des temps nécessaires à la réalisation des deux étapes étant au plus de 20 minutes.The process according to the invention for the extraction of uranium contained in phosphoric acid solutions by means of an extraction agent consisting of an alkylpyrophosphoric acid, which consists in bringing the mineral phase of phosphoric acid and an organic phase containing the extraction agent by creating an emulsion, is characterized in that, in an extraction unit comprising n stages in cascade with n> 1, for each extraction stage, the emulsion is produced during a first step by simultaneously subjecting the two phases for a time T, to an intense mechanical shearing action corresponding to a shear coefficient of at least 5000 s -1 in order to increase the contact surfaces between these two phases, then said emulsion during a second step is suddenly broken in a time T z , the total time required for the completion of the two steps being at most 20 minutes.

Il est apparu en effet à la titulaire, et ses travaux de recherche l'ont confirmé, qu'il est possible de réaliser l'extraction de l'uranium IV contenu dans les solutions d'acides phosphoriques au moyen d'un acide alkylpyrophosphorique avec un rendement d'au moins 98%, tout en conservant à l'agent d'extraction recyclé toute son efficacité, avec un appoint d'agent d'extraction neuf de 5 à 10 fois plus faible que dans les procédés selon l'art antérieur, à condition que l'on forme énergiquement une émulsion entre les deux phases minérale et organique dont la dimension des particules est généralement inférieure à 45 microns puis que l'on sépare rapidement ces deux phases en cassant l'équilibre de l'émulsion.It appeared to the licensee, and her research confirmed it, that it is possible to extract uranium IV from phosphoric acid solutions using an alkylpyrophosphoric acid with a yield of at least 98%, while retaining all the effectiveness of the recycled extractant, with a supply of new extractant 5 to 10 times lower than in the processes according to the prior art , provided that an emulsion is vigorously formed between the two mineral and organic phases, the particle size of which is generally less than 45 microns, then that these two phases are rapidly separated by breaking the equilibrium of the emulsion.

En général, l'unité d'extraction comporte un nombre d'étages n compris entre 2 et 20. Mais selon une variante, l'unité d'extraction peut être composée d'un seul étage et dans ce cas n = 1.In general, the extraction unit has a number of stages n of between 2 and 20. However, according to a variant, the extraction unit can be composed of a single stage and in this case n = 1.

Pour aboutir à l'obtention d'une suspension dont les particules ont une dimension en général inférieure à 45 microns, les phases minérale et organique doivent être soumises à une action mécanique de cisaillement intense correspondant à un coefficient de cisaillement très élevé. En général, ce coefficient de cisaillement est choisi dans l'intervalle 5000 s-1 à 50000 s-1, mais de préférence dans l'intervalle 10000 s-1 à 25000 s-1.In order to obtain a suspension whose particles generally have a size of less than 45 microns, the mineral and organic phases must be subjected to an intense mechanical shearing action corresponding to a very high shear coefficient. In general, this shear coefficient is chosen in the interval 5000 s -1 to 50,000 s -1 , but preferably in the interval 10,000 s -1 to 25,000 s -1 .

Le cumul des temps nécessaires à la réalisation des deux étapes selon l'invention est préférentiellement au plus égal à 10 minutes pour un étage d'extraction.The total time required to carry out the two stages according to the invention is preferably at most equal to 10 minutes for an extraction stage.

En outre, les temps T, et T d'exécution des deux étapes peuvent varier dans de larges limites, leur rapport T, /T2 pouvant être choisi dans les limites 1/100 à 5/1 et de préférence dans des limites 1/25 à 2/1.In addition, the times T, and T of execution of the two stages can vary within wide limits, their ratio T, / T 2 being able to be chosen within the limits 1/100 to 5/1 and preferably within limits 1 / 25 to 2/1.

L'émulsion entre les deux phases organique et minérale est réalisée par tout moyen connu de l'homme de l'art, permettant d'obtenir d'une manière rapide et énergique l'émulsion la plus fine possible, afin de multiplier les surfaces de contact et d'obtenir un très fort rendement d'extraction.The emulsion between the two organic and mineral phases is produced by any means known to those skilled in the art, making it possible to quickly and vigorously obtain the finest emulsion possible, in order to multiply the surfaces of contact and obtain a very high extraction yield.

En général, la séparation rapide des phases organique et minérale peut être obtenue par voie physique en utilisant tout moyen connu permettant une rupture rapide de ladite émulsion.In general, the rapid separation of the organic and mineral phases can be obtained by physical means using any known means allowing rapid rupture of said emulsion.

Parmi les moyens physiques permettant de produire puis de détruire l'émulsion très fine des phases organique et minérale, et de séparer très rapidement lesdites phases, il est possible d'utiliser des hydrocyclones aménagés, des extracteurs centrifuges multiétages ou encore des extracteurs centrifuges monoétages, organisés en batterie.Among the physical means making it possible to produce and then destroy the very fine emulsion of the organic and mineral phases, and to very quickly separate said phases, it is possible to use fitted hydrocyclones, multi-stage centrifugal extractors or even single-stage centrifugal extractors, organized in battery.

De même, et pour diminuer les pertes, l'agent d'extraction, entraîné par l'acide phosphorique désuranié peut être récupéré par une séparation physique de centrifugation par exemple et joint à l'agent d'extraction recyclé après réextraction de l'uranium.Likewise, and in order to reduce losses, the extracting agent, entrained by the desuranic phosphoric acid can be recovered by a physical separation of centrifugation for example and joined to the recycled extraction agent after re-extraction of the uranium .

Comme cela a été dit, l'agent d'extraction de l'uranium est choisi dans le groupe bien connu des acides alkylpyrophosphoriques, dont le radical al- kyl est une chaîne carbonée correspondant aux alcool en C7 à C13 obtenus par synthèse oxo, tels que par exemple l'octanol 2, l'éthylhexanol, le dé- canol. La préparation de l'acide alkylpyrophosphorique peut s'effectuer d'une manière connue par addition de P2O5 à l'alcool précité, utilisé seul ou en mélange avec un hydrocarbure.As has been said, the uranium extracting agent is chosen from the well-known group of alkylpyrophosphoric acids, the alkyl radical of which is a carbon chain corresponding to the C 7 to C 13 alcohols obtained by oxo synthesis , such as for example octanol 2, ethylhexanol, cancanol. The preparation of alkylpyrophosphoric acid can be carried out in a known manner by adding P 2 O 5 to the abovementioned alcohol, used alone or as a mixture with a hydrocarbon.

Le température de préparation de l'acide alkylpyrophosphorique est généralement comprise entre 30° C et 80° C, mais de préférence entre 30° C et 40° C.The temperature for preparing alkylpyrophosphoric acid is generally between 30 ° C and 80 ° C, but preferably between 30 ° C and 40 ° C.

L'agent d'extraction de l'uranium est généralement mis en solution dans un hydrocarbure aliphatique et/ou aromatique, tel que les kérosènes par exemple. Le mélange ainsi formé constitue la phase organique d'extraction de l'uranium, qui contient de 5 à 100 g/I mais de préférence de 20 à 50 g/I d'acide alkylpyrophosphorique.The uranium extracting agent is generally dissolved in an aliphatic and / or aromatic hydrocarbon, such as kerosene for example. The mixture thus formed constitutes the organic phase of extraction of the uranium, which contains from 5 to 100 g / l but preferably from 20 to 50 g / l of alkylpyrophosphoric acid.

En pratique, les solutions d'acides phosphoriques résultant de l'attaque de minerais phosphatés contiennent en général de 30 à 200 milligrammes d'uranium par litre, cet uranium étant pour une partie sous la forme U IV et pour l'autre sous la forme U VI.In practice, the phosphoric acid solutions resulting from the attack on phosphate ores generally contain from 30 to 200 milligrams of uranium per liter, this uranium being partly in the form U IV and for the other in the form U VI.

L'uranium VI est alors réduit en uranium IV par le traitement des solutions d'acides phosphoriques au moyen de fer, se présentant sous forme de poudre quand le traitement de réduction s'effectue en réacteur ou encore sous forme de déchets de ferrailles quand le traitement de réduction s'effectue dans une colonne.The uranium VI is then reduced to uranium IV by the treatment of phosphoric acid solutions with iron, in the form of powder when the reduction treatment is carried out in a reactor or also in the form of scrap metal when the reduction treatment takes place in a column.

Après que le traitement de réduction a été effectué, les solutions d'acides phosphoriques contenant en suspension des matières solides sont soumises à une opération de séparation, avant d'être mises en contact avec l'agent d'extraction en solution dans un hydrocarbure aliphatique et/ou aromatique.After the reduction treatment has been carried out, the phosphoric acid solutions containing suspended solids are subjected to a separation operation, before being brought into contact with the extractant in solution in an aliphatic hydrocarbon. and / or aromatic.

Les deux phases minérale et organique à extraire et extractante sont alors mises en contact intime sous la forme d'une fine émulsion qui est rapidement cassée afin de séparer la phase organique chargée en uranium de la phase minérale en acide désuraniée.The two mineral and organic phases to be extracted and extracting are then brought into intimate contact in the form of a fine emulsion which is quickly broken in order to separate the organic phase loaded with uranium from the mineral phase with deuranied acid.

Puis la phase organique chargée en uranium est alors traitée par une solution aqueuse d'acide fluorhydrique, cette solution contenant 10 à 20%, mais de préférence de 14 à 18% en poids de HF libre.The organic phase loaded with uranium is then treated with an aqueous hydrofluoric acid solution, this solution containing 10 to 20%, but preferably 14 to 18% by weight of free HF.

La température à laquelle s'effectue la réextraction de l'uranium par l'acide fluorhydrique est comprise entre 0° C et 60° C mais préférentiellement entre 10° C et 30° C, température à laquelle la dégradation de l'acide alkylpyrophosphorique reste faible (inférieure à 2%).The temperature at which the uranium is re-extracted by hydrofluoric acid is between 0 ° C and 60 ° C but preferably between 10 ° C and 30 ° C, temperature at which the degradation of the alkylpyrophosphoric acid remains low (less than 2%).

L'uranium précipite alors sous la forme d'UF4, qui est séparé du milieu liquide par un quelconque moyen choisi parmi ceux connus de l'homme de l'art.The uranium then precipitates in the form of UF 4 , which is separated from the liquid medium by any means chosen from those known to those skilled in the art.

L'acide alkylpyrophosphorique désuranié est alors recyclé directement à l'extraction de l'uranium contenu dans les solutions d'acides phosphoriques après recharge éventuelle en acide alkylpyrophosphorique neuf, tandis que les solutions d'acides phosphoriques désuraniées sontel- les-mêmes soumises à centrifugation pour récupérer l'agent d'extraction mécaniquement entraîné.The desuranized alkylpyrophosphoric acid is then recycled directly to the extraction of the uranium contained in the solutions of phosphoric acids after possible recharging with new alkylpyrophosphoric acid, while the solutions of desuranic phosphoric acids are themselves subjected to centrifugation to recover the mechanically driven extractant.

L'invention sera mieux comprise grâce aux exemples illustratifs.The invention will be better understood thanks to the illustrative examples.

Exemple 1Example 1

Cet exemple illustre le procédé d'extraction de l'uranium selon l'invention, au moyen d'acides alkylpyrophosphoriques comparativement au procédé d'extraction le plus couramment employé dans les procédés appartenant à l'art antérieur.This example illustrates the method of extracting uranium according to the invention, using alkylpyrophosphoric acids compared to the extraction method most commonly used in the processes belonging to the prior art.

Pour ce faire, on a traité un acide phosphorique ex Togo-Maroc ayant la composition suivante:

Figure imgb0001
To do this, we treated a phosphoric acid ex Togo-Morocco having the following composition:
Figure imgb0001

Cet acide est réduit soit par du fer en poudre dans une cuve agitée pour les essais 1 à 4, soit dans une colonne par du fer en plaquette pour les essais 5 et 6.This acid is reduced either by powdered iron in a stirred tank for tests 1 to 4, or in a column by plate iron for tests 5 and 6.

L'acide phosphorique réduit contient du Fe Il et du Fe III dans un rapport Fe II/Fe III compris entre 5 et 5,3.The reduced phosphoric acid contains Fe II and Fe III in an Fe II / Fe III ratio between 5 and 5.3.

L'acide phosphorique est traité par l'agent d'extraction en solution dans du kérosène à raison de 30 g/I. Le débit d'acide phosphorique réduit était de 200 1/h tandis que celui de la solution d'agent d'extraction était de 20 I/h.The phosphoric acid is treated with the extracting agent in solution in kerosene at a rate of 30 g / l. The reduced phosphoric acid flow rate was 200 l / h while that of the extractant solution was 20 l / h.

Le solvant chargé en uranium, après sa séparation d'avec l'acide phosphorique désuranié, était refroidi à 20° C puis traité par une solution de H F à 15%, au débit de 2 I/h.The solvent loaded with uranium, after its separation from the deuraniated phosphoric acid, was cooled to 20 ° C. and then treated with a 15% H F solution, at a flow rate of 2 l / h.

Le solvant désuranié était recyclé à l'extraction après ajout d'une fraction heure de l'agent d'extraction.The desuranized solvent was recycled to extraction after adding a fraction of an hour of the extractant.

L'essai N° 1, qui illustre l'art antérieur, a été réalisé dans une installation industrielle dont l'unité d'extraction était constituée par une batterie de 4 mélangeurs-décanteurs - unité d'extraction dans laquelle le cumul des temps T1 et T2 pour 4 étages tels que définis dans le procédé selon l'invention, est égal à 14 heures.Test No. 1, which illustrates the prior art, was carried out in an industrial installation whose extraction unit consisted of a battery of 4 mixer-settlers - extraction unit in which the cumulative times T 1 and T 2 for 4 stages as defined in the method according to the invention, is equal to 14 hours.

L'essai N° 2 illustrant l'invention a été réalisé dans une installation industrielle dont l'unité d'extraction était constituée par un extracteur centrifuge multiétages de 4 étages, tournant à la vitesse de 2800 tours par minute, unité dans laquelle le cumul des temps de séjour T, et Tz pour 4 étages était inférieur à deux minutes.Test No. 2 illustrating the invention was carried out in an industrial installation, the extraction unit of which consisted of a 4-stage multi-stage centrifugal extractor, rotating at the speed of 2800 rpm, a unit in which the accumulation residence times T, and T z for 4 stages was less than two minutes.

L'essai N° 3, illustrant l'art antérieur, diffère de l'essai N° 1 par la nature de l'agent d'extraction qui était dans ce cas une solution d'acide éthylhexylpyrophosphorique.Test No. 3, illustrating the prior art, differs from test No. 1 in the nature of the extractant which in this case was a solution of ethylhexylpyrophosphoric acid.

L'essai N° 4, illustrant l'invention, diffère de l'essai N° 2 par la nature de l'agent d'extraction qui était l'acide éthylhexylpyrophosphorique.Test No. 4, illustrating the invention, differs from test No. 2 in the nature of the extractant which was ethylhexylpyrophosphoric acid.

L'essai N° 5, illustrant l'art antérieur, ne diffère de l'essai N° 1 que par le mode de réduction de l'acide phosphorique (sur plaquettes en colonne).Test No. 5, illustrating the prior art, differs from test No. 1 only in the mode of reduction of phosphoric acid (on platelets in column).

L'essai N° 6, illustrant l'invention, diffère de l'essai N° 2 par le mode de réduction de l'acide phosphorique et par la constitution de l'unité d'extraction qui comportait quatre extracteurs centrifuges monoétages en batterie - unité dans laquelle le cumul des temps de séjour T, et T2 était inférieur à deux minutes.Test N ° 6, illustrating the invention, differs from test N ° 2 by the mode of reduction of phosphoric acid and by the constitution of the extraction unit which included four single stage centrifugal extractors in battery - unit in which the cumulative residence times T, and T 2 was less than two minutes.

Tous les résultats ont été consignés dans le tableau 1 ci-après:

  • (Tableau en page suivante)
All the results have been reported in Table 1 below:
  • (Table on next page)

A travers les résultats ainsi rassemblés, il est possible de mesurer l'importance du procédé selon l'invention qui améliore le rendement d'extraction de l'uranium, mais réduit de 5 à 6 fois la consommation en agent d'extraction.Through the results thus collected, it is possible to measure the importance of the process according to the invention which improves the uranium extraction yield, but reduces the consumption of extractant by 5 to 6 times.

Exemple 2Example 2

Cet exemple illustre le procédé d'extraction de l'uranium selon l'invention, au moyen d'acides alkylpyrophosphoriques, comparativement au procédé d'extraction le plus couramment employé dans les procédés appartenant à l'art antérieur.This example illustrates the method of extracting uranium according to the invention, using alkylpyrophosphoric acids, compared to the extraction method most commonly used in methods belonging to the prior art.

Il concerne le traitement d'un acide phosphorique d'origine tunisienne à faible teneur en uranium.

Figure imgb0002
It concerns the treatment of a phosphoric acid of Tunisian origin with low uranium content.
Figure imgb0002

L'acide phosphorique traité avait la composition suivante:

Figure imgb0003
The phosphoric acid treated had the following composition:
Figure imgb0003

L'essai N° 7, qui illustre l'art antérieur, a été con- duitcomme l'essai 1, dans une batterie de 4 mélangeurs-décanteurs.Test No. 7, which illustrates the prior art, was carried out like test 1, in a battery of 4 mixer-settlers.

L'essai N° 8, qui illustre l'invention, a été réalisé comme l'essai 2, mais en faisant usage d'une batterie comportant 3 extracteurs centrifuges monoétages.Test No. 8, which illustrates the invention, was carried out like test 2, but using a battery comprising 3 single-stage centrifugal extractors.

Les résultats ont été consignés dans le tableau 2 ci-après:

Figure imgb0004
The results are reported in Table 2 below:
Figure imgb0004

Ce deuxième tableau confirme les excellents résultats obtenus par l'exemple 1.This second table confirms the excellent results obtained by Example 1.

Claims (17)

1. A process for extracting the uranium contained in solutions of phosphoric acids by means of an extraction agent formed by an alkylpyrophosphoric acid comprising bringing into contact, with agitation, the phosphoric acid mineral phase and an organic phase containing the extraction agent, creating an emulsion, characterized in that, in an extraction unit comprising one or more stages in a cascade array, for each extraction stage, the emulsion is produced in a first step by simultaneously subjecting the two phases containing the phosphoric acid and the extraction agent, for a time T,, to an intense mechanical shearing action corresponding to a shearing coefficient of at least 5000 s-', in order to multiply the contact surfaces between said two phases, then said emulsion, in a second step, is abruptly broken in a time T2, the sum T1 + T of the times required for carrying out the two steps being at most 20 minutes.
2. A uranium extraction process according to Claim 1 characterized in that the extraction unit comprises a number of stages of between 2 and 20.
3. A uranium extraction process according to Claim 1 characterized in that the extraction unit comprises a single stage.
4. A uranium extraction process according to any one of Claims 1 to 3 characterized in that the shearing coefficient is selected to lie in the range of from 5000 s-1 to 50000 s-1.
5. A uranium extraction process according to Claim 4 characterized in that the shearing coefficient is selected to lie in the range of from 10000 s-1 to 25000 s-1.
6. A uranium extraction process according to any one of Claims 1 to 4 characterized in that the sum T, +T2 of the times required for carrying out the two steps is at most equal to 10 minutes for an extraction stage.
7. A uranium extraction process according to any one of Claims 1 to 6 characterized in that the ratio T, IT of the times for carrying out the two steps for an extraction stage is within the limits of 1 /100 to 5/1.
8. A uranium extraction process according to Claim 7 characterized in that the ratio T1/T2 is selected to lie within the limits 1/25 to 2/1.
9. A uranium extraction process according to any one of Claims 1 to 7 characterized in that the extraction agent which is an alkylpyrophosphoric acid is produced by the addition of P2O5 to an alcohol having a C7 to C13 carbon chain.
10. A uranium extraction process according to Claim 9 characterized in that the temperature at which the alkylpyrophosphoric acid is produced is from 30 to 80° C.
11. A uranium extraction process according to Claim 10 characterized in that the temperature is from 30 to 40° C.
12. A uranium extraction process according to any one of Claims 1 to 10 characterized in that the organic phase charged with uranium resulting from the second step is treated with a solution of hydrofluoric acid to re-extract the uranium.
13. A uranium extraction process according to Claim 12 characterized in that the solution of hydrofluoric acid contains from 10 to 20% by weight of H F.
14. A uranium extraction process according to Claim 13 characterized in that the solution contains from 14 to 18% by weight of HF.
15. A uranium extraction process according to Claim 12 characterized in that the temperature at which the operation of re-extracting the uranium by the hydrofluoric acid is effected is from 0 to 60° C.
16. A uranium extraction process according to Claim 15 characterized in that the temperature is from 10 to 30° C.
17. A uranium extraction process according to any one of Claims 1 to 15 characterized in that the extraction agent which is entrained by the phosphoric acid is recovered by centrifuging.
EP83420127A 1982-07-30 1983-07-20 Process for extracting uranium from phosphoric acids using alkylpyrophosphoric acids Expired EP0100744B1 (en)

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FR2573415B1 (en) * 1984-11-16 1986-12-12 Pechiney Uranium PROCESS FOR RECOVERY IN THE FORM OF TETRAVALENT FLUORIDE OF URANIUM EXTRACTED FROM PHOSPHATE SOLUTIONS
US5463177A (en) * 1994-08-23 1995-10-31 General Electric Company Solvent extraction process
KR100675919B1 (en) * 2005-11-08 2007-06-04 정영기 Method for separating uranium isotopes by using a centrifuge
US8226910B2 (en) * 2008-07-31 2012-07-24 Urtek, Llc Extraction of uranium from wet-process phosphoric acid
US8883096B2 (en) 2008-07-31 2014-11-11 Urtek, Llc Extraction of uranium from wet-process phosphoric acid

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US2847275A (en) * 1955-01-04 1958-08-12 James H Yeager Uranium recovery process
DE1168867B (en) * 1958-01-29 1964-04-30 Atomic Energy Of Canada Ltd Device for continuous countercurrent extraction of two immiscible liquids
US3416320A (en) * 1967-07-14 1968-12-17 Exxon Research Engineering Co Turbo-jet propulsion method using emulsified fuels and demulsification
GB1596410A (en) * 1976-12-27 1981-08-26 Exxon Research Engineering Co Liquid membranes and process for uranium recovery therewith
FR2376688A1 (en) * 1977-01-10 1978-08-04 Anglian Water Authority Appts. for forming sewage treatment silicate prods. - includes mixing tube with static high shear device
US4180545A (en) * 1977-03-25 1979-12-25 Tennessee Valley Authority Uranium recovery from wet-process phosphoric acid
US4154698A (en) * 1977-06-08 1979-05-15 Nalco Chemical Company Resolution of oil-in-water emulsions containing uranium
FR2423545A1 (en) * 1977-08-25 1979-11-16 Minemet Rech Sa PROCESS FOR THE RECOVERY OF URANIUM CONTAINED IN PHOSPHATE SOLUTIONS
US4243637A (en) * 1977-10-11 1981-01-06 Occidental Petroleum Company Uranium recovery from pre-treated phosphoric acid
US4311676A (en) * 1978-09-08 1982-01-19 Minemet Recherche Process for the recovery of uranium contained in phosphated compounds
US4293529A (en) * 1978-10-27 1981-10-06 Uranium Recovery Corporation Process for recovering uranium from wet-process phosphoric acid using alkyl pyrophosphoric acid extractants
US4292278A (en) * 1979-02-21 1981-09-29 Wyoming Mineral Corp. Purification of wet process phosphoric acid as a pretreatment step in the recovery of uranium
US4287071A (en) * 1979-10-10 1981-09-01 Occidental Research Corporation Simultaneous extraction of more than one ion by liquid membrane process

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