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Sample records for extracting uranium bycontinuous

  1. Uranium extraction from gold-uranium ores

    Energy Technology Data Exchange (ETDEWEB)

    Laskorin, B.N.; Golynko, Z.Sh.

    1981-01-01

    The process of uranium extraction from gold-uranium ores in the South Africa is considered. Flowsheets of reprocessing gold-uranium conglomerates, pile processing and uranium extraction from the ores are presented. Continuous counter flow ion-exchange process of uranium extraction using strong-active or weak-active resins is noted to be the most perspective and economical one. The ion-exchange uranium separation with the succeeding extraction is also the perspective one.

  2. Gold and uranium extraction

    International Nuclear Information System (INIS)

    James, G.S.; Davidson, R.J.

    1977-01-01

    A process for extracting gold and uranium from an ore containing them both comprising the steps of pulping the finely comminuted ore with a suitable cyanide solution at an alkaline pH, acidifying the pulp for uranium dissolution, adding carbon activated for gold recovery to the pulp at a suitable stage, separating the loaded activated carbon from the pulp, and recovering gold from the activated carbon and uranium from solution

  3. Uranium extraction at Rossing

    International Nuclear Information System (INIS)

    Kesler, S.B.; Fahrbach, D.O.E.

    1982-01-01

    Rossing Uranium Ltd. operates a large open pit uranium mine and extraction plant at a remote site in the Namib desert. Production started at the plant in 1978. A ferric leach process was introduced later, and the new leach plant began commissioning in October 1981. The process has proved to be reliable and easily controlled. Ferric iron is supplied through recovery from the acid plant calcine, and levels can be maintained above the design levels. Leach extractions were increased more than expected when this process was adopted, and the throughput has been considerably reduced, allowing cost savings in mining and milling

  4. Uranium extraction technology

    International Nuclear Information System (INIS)

    1993-01-01

    In 1983 the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD/NEA) and the IAEA jointly published a book on Uranium Extraction Technology. A primary objective of this report was to document the significant technological developments that took place during the 1970s. The purpose of this present publication is to update and expand the original book. It includes background information about the principle of the unit operations used in uranium ore processing and summarizes the current state of the art. The publication also seeks to preserve the technology and the operating 'know-how' developed over the past ten years. This publication is one of a series of Technical Reports on uranium ore processing that have been prepared by the Division of Nuclear Fuel Cycle and Waste Management at the IAEA. A complete list of these reports is included as an addendum. Refs, figs and tabs

  5. Uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    Araujo Figueiredo, C. de

    1984-01-01

    The recovery of uranium from phosphoric liquor by two extraction process is studied. First, uranium is reduced to tetravalent condition and is extracted by dioctypyrophosphoric acid. The re-extraction is made by concentrated phosphoric acid with an oxidizing agent. The re-extract is submitted to the second process and uranium is extracted by di-ethylhexilphosphoric acid and trioctylphosphine oxide. (M.A.C.) [pt

  6. Uranium extraction from underground deposits

    International Nuclear Information System (INIS)

    Wolfe, C.R.

    1982-01-01

    Uranium is extracted from underground deposits by passing an aqueous oxidizing solution of carbon dioxide over the ore in the presence of calcium ions. Complex uranium carbonate or bicarbonate ions are formed which enter the solution. The solution is forced to the surface and the uranium removed from it

  7. Uranium extraction in phosphoric acid

    International Nuclear Information System (INIS)

    Araujo Figueiredo, C. de

    1984-01-01

    Uranium is recovered from the phosphoric liquor produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). The proposed process consists of two extraction cycles. In the first one, uranium is reduced to its tetravalent state and then extracted by dioctylpyrophosphoric acid, diluted in Kerosene. Re-extraction is carried out with concentrated phosphoric acid containing an oxidising agent to convert uranium to its hexavalent state. This extract (from the first cycle) is submitted to the second cycle where uranium is extracted with DEPA-TOPO (di-2-hexylphosphoric acid/tri-n-octyl phosphine oxide) in Kerosene. The extract is then washed and uranium is backextracted and precipitated as commercial concentrate. The organic phase is recovered. Results from discontinuous tests were satisfactory, enabling to establish operational conditions for the performance of a continuous test in a micro-pilot plant. (Author) [pt

  8. Uranium refining by solvent extraction

    International Nuclear Information System (INIS)

    Kraikaew, J.; Srinuttrakul, W.

    2014-01-01

    The solvent extraction process to produce higher purity uranium from yellowcake was studied in laboratory scale. Yellowcake, which the uranium purity is around 70% and the main impurity is thorium, was obtained from monazite processing pilot plant of Rare Earth Research and Development Center in Thailand. For uranium re-extraction process, the extractant chosen was Tributylphosphate (TBP) in kerosene. It was found that the optimum concentration of TBP was 10% in kerosene and the optimum nitric acid concentration in uranyl nitrate feed solution was 4 N. An increase in concentrations of uranium and thorium in feed solution resulted in a decrease in the distribution of both components in the extractant. However, the distribution of uranium into the extractant was found to be more than that of thorium. The equilibration study of the extraction system, UO_2(NO_3)/4N HNO_3 – 10%TBP/Kerosene, was also investigated. Two extraction stages were calculated graphically from 100,000 ppm uranium concentration in feed solution input with 90% extraction efficiency and the flow ratio of aqueous phase to organic phase was adjusted to 1.0. For thorium impurity scrubbing process, 10% TBP in kerosene was loaded with uranium and minor thorium from uranyl nitrate solution prepared from yellowcake and was scrubbed with different low concentration nitric acid. The results showed that at nitric acid normality was lower than 1 N, uranium distributed well to aqueous phase. As conclusion, optimum nitric acid concentration for scrubbing process should not less than 1 N and diluted nitric acid or de-ionized water should be applied to strip uranium from organic phase in the final refining process. (author)

  9. Supercritical fluid extraction of uranium

    International Nuclear Information System (INIS)

    Kumar, Pradeep

    2017-01-01

    Uranium being strategic material, its separation and purification is of utmost importance in nuclear industry, for which solvent extraction is being employed. During solvent extraction significant quantity of radioactive liquid waste gets generated which is of environmental concern. In recent decades supercritical fluid extraction (SFE) has emerged as promising alternative to solvent extraction owing to its inherent advantage of reduction in liquid waste generation and simplification of process. In this paper a brief overview of research work carried out so far on SFE of uranium by BARC has been given

  10. Uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    Lounis, A.

    1983-05-01

    A study has been carried out for the extraction of uranium from phosphoric acid produced in Algeria. First of all, the Algerian phosphoric acid produced in Algeria by SONATRACH has been characterised. This study helped us to synthesize a phosphoric acid that enabled us to pass from laboratory tests to pilot scale tests. We have then examined extraction and stripping parameters: diluent, DZEPHA/TOPO ratio and oxidising agent. The laboratory experiments enabled us to set the optimum condition for the choice of diluent, extractant concentration, ratio of the synergic mixture, oxidant concentration, redox potential. The equilibrium isotherms lead to the determination of the number of theoretical stages for the uranium extraction and stripping of uranium, then the extraction from phosphoric acid has been verified on a pilot scale (using a mixer-settler)

  11. EXTRACTION OF URANIUM

    Science.gov (United States)

    Kesler, R.D.; Rabb, D.D.

    1959-07-28

    An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

  12. Uranium extraction from seawater

    International Nuclear Information System (INIS)

    Bals, H.G.

    1976-03-01

    After an introduction to the physics and chemistry of the sea and an estimation of the chances for the absorption of uranium from rivers, the material-sepecific characteristics of the adsorber technology are decribed in detail. Then, the methods used for gaining uranium form seawater are described with special regard to the tidal and the so-called serial (sequency) method. Whether all methods described can be realised is an economic problem since very high quantitics of water are necessary because of the low contents of uranium. A positive energy balance (gained energy/lost energy) is not definitely ensured yet for the production methods used. The development measures to be taken to obtain a positive energy balance are briefly described, and the research programme of the UEBG is mentioned. (UA) [de

  13. Amine synergism in uranium extraction

    International Nuclear Information System (INIS)

    Rinelli, G.; Abbruzzese, C.

    1977-01-01

    Commercial products based on C 8 to C 12 tertiary amine mixtures are now widely used in the solvent extraction of uranium from sulphuric pregnant solutions. The satisfactory results generally obtained have never required an analysis of the synergistic effects of amine combinations similar to that carried out for the organo-phosphorus compounds. In the research described the increase in the extraction power of an organic phase composed of an amine binary mixture was studied with regard to an aqueous solution from the sulphuric acid treatment of uranium ore. On the basis of the experimental results obtained, it is possible to select the best composition of the amine mixture to ensure a percentage increase in uranium recovery. Bearing in mind the tendency for the yellow-cake price to rise, the study is considered to be a useful contribution in the context of commercial products currently available on the market. (author)

  14. Extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Kanno, M.

    1977-01-01

    The nuclear power generation is thought to be very important in Japan. However, known domestic uranium resources in Japan are very rare. So, extraction of uranium from sea water have been carried out since 1962 at Japan Tobacco and Salt Public Corporation. There are a number of results obtained also by Kyoto University, Shikoku Govenment Industrial Research Institute, Tokyo University and others. In order to investigate the technical and economical feasibility of extraction of uranium and other resources from sea water, a research program was started in fiscal 1975, sponsored by the Ministry of International Trade and Industry with the budget of about $440,000. In this program, the conceptional design of two types of model plants, the ''column type'' and the ''tidal type'' was drawn on the design bases set up with available information. It was found that there has been several problems waiting solution, but there were no technically fatal problems. Adsorption tests were carried out with adsorbents of more than eleven types, including titanium hydroxide, and it was found that titanium hydroxide made by titanyl surphate and urea had the largest adsorption capacity of uranium among them. Elution experiments were performed only with ammonium carbonate and the efficiency at the temperature of 60 0 C showed three times higher than that of 20 0 C. A few long term column operation was conducted, mainly with the adsorbent of granulated titanium hydroxide for 15-60 days. The maximum yield of uranium throughout the adsorption and elution operation was over 20% and macimum concentration of uranium in eluate was 7 ppm

  15. Sequential extraction of uranium metal contamination

    International Nuclear Information System (INIS)

    Murry, M.M.; Spitz, H.B.; Connick, W.B.

    2016-01-01

    Samples of uranium contaminated dirt collected from the dirt floor of an abandoned metal rolling mill were analyzed for uranium using a sequential extraction protocol involving a series of five increasingly aggressive solvents. The quantity of uranium extracted from the contaminated dirt by each reagent can aid in predicting the fate and transport of the uranium contamination in the environment. Uranium was separated from each fraction using anion exchange, electrodeposition and analyzed by alpha spectroscopy analysis. Results demonstrate that approximately 77 % of the uranium was extracted using NH 4 Ac in 25 % acetic acid. (author)

  16. Biotechnology for uranium extraction and environmental control

    International Nuclear Information System (INIS)

    Natarajan, K.A.

    2012-01-01

    India is looking forward to augmenting mining and extraction of uranium mineral for its nuclear energy needs. Being a radio-active mineral, mining and processing of uranium ore deposits need be carried out in an environmentally acceptable fashion. In this respect, a biotechnological approach holds great promise since it is environment-friendly, cost-effective and energy-efficient. There are several types of microorganisms which inhabit uranium ore bodies and biogenesis plays an important role in the mineralisation and transport of uranium-bearing minerals under the earth's crust. Uranium occurrences in India are only meagre and it becomes essential to tap effectively all the available resources. Uraninite and pitchblende occurring along with sulfide mineralisation such as pyrite are ideal candidates for bioleaching. Acidithiobacillus ferrooxidans present ubiquitously in the ore deposits can be isolated, cultured and utilised to bring about efficient acidic dissolution of uranium. Many such commercial attempts to extract uranium from even lean ores using acidophilic autotrophic bacteria have been made in different parts of the world. Anaerobes such a Geobacter and Sulfate Reducing Bacteria (SRB) can be effectively used in uranium mining for environmental control. Radioactive uranium mined wastes and tailing dumps can be cleaned and protected using microorganisms. In this lecture use of biotechnology in uranium extraction and bioremediation is illustrated with practical examples. Applicability of environment-friendly biotechnology for mining and extraction of uranium from Indian deposits is outlined. Commercial potentials for bioremediation in uranium-containing wastes are emphasised. (author)

  17. Rate phenomena in uranium extraction by amines

    International Nuclear Information System (INIS)

    Coleman, C.F.; McDowell, W.J.

    1979-01-01

    Kinetics studies and other rate measurements are reviewed in the amine extraction of uranium and of some other related and associated metal ions. Equilibration is relatively fast in the uranium sulfate systems most important to uranium hydrometallurgy. Significantly slow equilibration has been encountered in some other systems. Most of the recorded rate information, both qualitative and quantitative, has come from exploratory and process-development work, while some kinetics studies have been directed specifically toward elucidation of extraction mechanisms. 71 references

  18. Depleted uranium processing and fluorine extraction

    International Nuclear Information System (INIS)

    Laflin, S.T.

    2010-01-01

    Since the beginning of the nuclear era, there has never been a commercial solution for the large quantities of depleted uranium hexafluoride generated from uranium enrichment. In the United States alone, there is already in excess of 1.6 billion pounds (730 million kilograms) of DUF_6 currently stored. INIS is constructing a commercial uranium processing and fluorine extraction facility. The INIS facility will convert depleted uranium hexafluoride and use it as feed material for the patented Fluorine Extraction Process to produce high purity fluoride gases and anhydrous hydrofluoric acid. The project will provide an environmentally friendly and commercially viable solution for DUF_6 tails management. (author)

  19. Extraction and desorption of accessible uranium

    International Nuclear Information System (INIS)

    Payne, T.

    1987-01-01

    The proportion of the uranium in natural ore samples which is in isotopic equilibrium with the uranium in the groundwater may be designated accessible uranium, and can be regarded as being in short-term exchange with the aqueous phase. Some of the natural uranium is secured in resistant crystalline minerals, and is described as inaccessible, because it may not be brought into solution unless the mineral is subjected to extreme chemical attack. It is not available for groundwater transport in the short term. An estimate of the proportion of accessible uranium is therefore useful when modeling radionuclide migration. The amount of accessible natural uranium is some uranium ore samples from the Ranger deposit has been determined by combining a sequential extraction with isotopic measurements of the extracted phases. The solid samples were crushed drill core form Ranger S1/146 which had previously been used for uranium adsorption experiments and therefore contained 236 U as well as natural uranium. This Section discusses how the uranium partitioning found with the sequential extraction procedure predicts the leaching behavior of these samples

  20. Uranium extraction by complexation with siderophores

    Science.gov (United States)

    Bahamonde Castro, Cristina

    One of the major concerns of energy production is the environmental impact associated with the extraction of natural resources. Nuclear energy fuel is obtained from uranium, an abundant and naturally occurring element in the environment, but the currently used techniques for uranium extraction leave either a significant fingerprint (open pit mines) or a chemical residue that alters the pH of the environment (acid or alkali leaching). It is therefore clear that a new and greener approach to uranium extraction is needed. Bioleaching is one potential alternative. In bioleaching, complexants naturally produced from fungi or bacteria may be used to extract the uranium. In the following research, the siderophore enterobactin, which is naturally produced by bacteria to extract and solubilize iron from the environment, is evaluated to determine its potential for complexing with uranium. To determine whether enterobactin could be used for uranium extraction, its acid dissociation and its binding strength with the metal of interest must be determined. Due to the complexity of working with radioactive materials, lanthanides were used as analogs for uranium. In addition, polyprotic acids were used as structural and chemical analogs for the siderophore during method development. To evaluate the acid dissociation of enterobactin and the subsequent binding constants with lanthanides, three different analytical techniques were studied including: potentiometric titration, UltraViolet Visible (UV-Vis) spectrophotometry and Isothermal Titration Calorimetry (ITC). After evaluation of three techniques, a combination of ITC and potentiometric titrations was deemed to be the most viable way for studying the siderophore of interest. The results obtained from these studies corroborate the ideal pH range for enterobactin complexation to the lanthanide of interest and pave the way for determining the strength of complexation relative to other naturally occurring metals. Ultimately, this

  1. Enhancement of Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sheikhly, Mohamad [Univ. of Maryland, College Park, MD (United States); Dietz, Travis [Univ. of Maryland, College Park, MD (United States); Tsinas, Zois [Univ. of Maryland, College Park, MD (United States); Tomaszewski, Claire [Univ. of Maryland, College Park, MD (United States); Pazos, Ileana M. [Univ. of Maryland, College Park, MD (United States); Nigliazzo, Olga [The Catholic Univ. of America, Washington, DC (United States); Li, Weixing [The Catholic Univ. of America, Washington, DC (United States); Adel-Hadadi, Mohamad [Univ. of Maryland, College Park, MD (United States); Barkatt, Aaron [Univ. of Palermo (Italy)

    2016-04-01

    Even at a concentration of 3 μg/L, the world’s oceans contain a thousand times more uranium than currently know terrestrial sources. In order to take advantage of this stockpile, methods and materials must be developed to extract it efficiently, a difficult task considering the very low concentration of the element and the competition for extraction by other atoms in seawater such as sodium, calcium, and vanadium. The majority of current research on methods to extract uranium from seawater are vertical explorations of the grafting of amidoxime ligand, which was originally discovered and promoted by Japanese studies in the late 1980s. Our study expands on this research horizontally by exploring the effectiveness of novel uranium extraction ligands grafted to the surface of polymer substrates using radiation. Through this expansion, a greater understanding of uranium binding chemistry and radiation grafting effects on polymers has been obtained. While amidoxime-functionalized fabrics have been shown to have the greatest extraction efficiency so far, they suffer from an extensive chemical processing step which involves treatment with powerful basic solutions. Not only does this add to the chemical waste produced in the extraction process and add to the method’s complexity, but it also significantly impacts the regenerability of the amidoxime fabric. The approach of this project has been to utilize alternative, commercially available monomers capable of extracting uranium and containing a carbon-carbon double bond to allow it to be grafted using radiation, specifically phosphate, oxalate, and azo monomers. The use of commercially available monomers and radiation grafting with electron beam or gamma irradiation will allow for an easily scalable fabrication process once the technology has been optimized. The need to develop a cheap and reliable method for extracting uranium from seawater is extremely valuable to energy independence and will extend the quantity of

  2. Enhancement of Extraction of Uranium from Seawater

    International Nuclear Information System (INIS)

    Al-Sheikhly, Mohamad; Dietz, Travis; Tsinas, Zois; Tomaszewski, Claire; Pazos, Ileana M.; Nigliazzo, Olga; Li, Weixing; Adel-Hadadi, Mohamad; Barkatt, Aaron

    2016-01-01

    Even at a concentration of 3 @@g/L, the world@@@s oceans contain a thousand times more uranium than currently know terrestrial sources. In order to take advantage of this stockpile, methods and materials must be developed to extract it efficiently, a difficult task considering the very low concentration of the element and the competition for extraction by other atoms in seawater such as sodium, calcium, and vanadium. The majority of current research on methods to extract uranium from seawater are vertical explorations of the grafting of amidoxime ligand, which was originally discovered and promoted by Japanese studies in the late 1980s. Our study expands on this research horizontally by exploring the effectiveness of novel uranium extraction ligands grafted to the surface of polymer substrates using radiation. Through this expansion, a greater understanding of uranium binding chemistry and radiation grafting effects on polymers has been obtained. While amidoxime-functionalized fabrics have been shown to have the greatest extraction efficiency so far, they suffer from an extensive chemical processing step which involves treatment with powerful basic solutions. Not only does this add to the chemical waste produced in the extraction process and add to the method@@@s complexity, but it also significantly impacts the regenerability of the amidoxime fabric. The approach of this project has been to utilize alternative, commercially available monomers capable of extracting uranium and containing a carbon-carbon double bond to allow it to be grafted using radiation, specifically phosphate, oxalate, and azo monomers. The use of commercially available monomers and radiation grafting with electron beam or gamma irradiation will allow for an easily scalable fabrication process once the technology has been optimized. The need to develop a cheap and reliable method for extracting uranium from seawater is extremely valuable to energy independence and will extend the quantity of

  3. Uranium refining by solvent extraction

    International Nuclear Information System (INIS)

    Kraikaew, J.

    1996-01-01

    The yellow cake refining was studied in both laboratory and semi-pilot scales. The process units mainly consist of dissolution and filtration, solvent extraction, and precipitation and filtration. Effect of flow ratio (organic flow rate/ aqueous flow rate) on working efficiencies of solvent extraction process was studied. Detailed studies were carried out on extraction, scrubbing and stripping processes. Purity of yellow cake product obtained is high as 90.32% U 3 O 8

  4. Present status of uranium extraction from seawater

    International Nuclear Information System (INIS)

    Kusakabe, Katsuki; Morooka, Shigeharu

    1993-01-01

    For the research on the extraction of uranium from seawater, various processes have been examined, but the most promising process is adsorption. Its key point is the performance of the adsorbent. The system as compact as possible, in which a large quantity of seawater effectively contacts with the adsorbent, must be constructed economically. As the inorganic adsorbent, titanium oxide is the best, but organic amidoxime is superior to it. The present state of the development of the adsorbent, the rate of adsorption of the adsorbenbt, the seawater uranium adsorption system and the experiment in Imari Bay are reported. (K.I.)

  5. Uranium extraction from colofanite via organic solvents

    International Nuclear Information System (INIS)

    Ribeiro, Valeria Aparecida Leitao

    2007-01-01

    This work describes the use of pure or combined extractants dissolved in organic solvents for quantitative uranium recovery from colofanite, a fluoroapatite ore, from Itataia, Santa Quiteria, Ceara, Brazil. This ore contains the highest brazilian uranium reserve. The metal is associated to phosphate species. The ore is digested with sulfuric acid (wet process), producing phosphoric acid, which is used for manufacturing of fertilizers and animal food. >From the acid leaching, some systems for uranium recovery were tested. Among them, PC88A (2-ethyl-hexyl phosphonic acid, mono-2-ethyl-hexyl ester) 40% vol. and DEHPA (di(2-ethyl-hexyl)phosphoric acid) 40% vol. in kerosene presented the highest values for the distribution coefficient (D) for uranium. When synergistic systems were employed, the best results were obtained for DEHPA 40%vol. + PC88A 40%vol. and DEHPA 40% vol. + TOPO (trioctylphosphine oxide) 5% vol. in kerosene. 15% wt/v sodium carbonate was the best medium for uranium stripping and separation from iron, the main interfering element. Uranium was precipitated as sodium diuranate by adding sodium hydroxide (5,0 mol L -1 ). Thorium in the raffinate was extracted by TOPO (0,1% vol.) in cyclohexane. The radioactivity level of the final aqueous waste is similar to natural background, according to CNEN-NE 6.05 Norm. After neutralization, the solid can be co-processed, according to the Directory 264 from the National Brazilian Environmental Council (CONAMA), whereas the treated effluent can be discarded according to the Directory 357 from CONAMA. (author)

  6. Extraction of uranium from carnotite/tyuyamunite

    International Nuclear Information System (INIS)

    Li Shengnian; Fang Xuxia

    1998-01-01

    According to the characters of a carnotite/tyuyamunite and chemical properties of vanadate, the technological process, heap leaching-ion exchange-precipitation, is adopted for extracting uranium. It has been proved through laboratory test and industrial trial production that process is simple and convenient in method, advanced in technology, simple in equipment, and the product quality conforms to the criterion. The technological process is applied to small-sized hydrometallurgy plant at mine

  7. Extraction behavior of uranium(VI) with polyurethane foam

    International Nuclear Information System (INIS)

    Tingchia Huang; Donghwang Chen; Muchang Shieh; Chingtsven Huang

    1992-01-01

    The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(IV) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically

  8. Extraction of uranium with emulsion membrane process use tributylphosphate extractant

    International Nuclear Information System (INIS)

    Basuki, K.T.; Sudibyo, R.; Bambang EHB; Muhadi, A.W.

    1996-01-01

    To increase the effectiveness of extraction process with so for to occur, it was tried the extraction with a couple of extraction and stripping process. This couple process was called liquid membrane emulsion. As membrane was used mix surfactant (Span-80), tributylphosphate in kerosene, natrium carbonate, while as a feeder was uranium solution with 500 concentration ppm in 0.5 - 3 M nitrate acid. In this experiment the variable investigated were % surfactant (1 - 5 %), rotary speed for membrane making (2,500 - 10.000 rpm). The optimal condition result of experiment were 5 % surfactant, 3 M nitrate acid, rotary speed 10.000 rpm and (Kd eksU ) 57 %, and (Kd strippU ) 87 %, Kd eksU at liquid-liquid extraction is 44 %. (author)

  9. Study for the extraction of uranium from commerical phosphoric acid

    International Nuclear Information System (INIS)

    Nogueira, A.C.R.

    1984-01-01

    The extraction of uranium is discribed and for which several parameters such as choice of the extracting agent, uranium oxidation, temperature, phase volume ratio, equilibrium time and number of stages are studied. A synergic mixture constituted by 0,5M DZEHPA/0,125M TOPO in kerosene is used as extracting agent. The uranium extraction is performed by using both batch process and continuous as well as discontinuous counter-current and processes in bench scale. An overall yield of 96% is obtained when the extraction experiment is performed at 45 0 C in a 5-stage continuous extraction process. (Author) [pt

  10. Uranium

    International Nuclear Information System (INIS)

    Hamdoun, N.A.

    2007-01-01

    The article includes a historical preface about uranium, discovery of portability of sequential fission of uranium, uranium existence, basic raw materials, secondary raw materials, uranium's physical and chemical properties, uranium extraction, nuclear fuel cycle, logistics and estimation of the amount of uranium reserves, producing countries of concentrated uranium oxides and percentage of the world's total production, civilian and military uses of uranium. The use of depleted uranium in the Gulf War, the Balkans and Iraq has caused political and environmental effects which are complex, raising problems and questions about the effects that nuclear compounds left on human health and environment.

  11. Uranium extraction history using pressure leaching

    International Nuclear Information System (INIS)

    Fraser, K.S.; Thomas, K.G.

    2010-01-01

    Over the past 60 years of uranium process development only a few commercial uranium plants have adopted a pressure leaching process in their flowsheet. The selection of acid versus alkaline pressure leaching is related to the uranium and gangue mineralogy. Tetravalent (U"+"4) uranium has to be oxidized to hexavalent (U"+"6) uranium to be soluble. Refractory tetravalent uranium requires higher temperature and pressure, as practised in pressure leaching, for conversation to soluble hexavalent uranium. This paper chronicles the history of these uranium pressure leaching facilities over the past 60 years, with specific details of each design and operation. (author)

  12. Solvent extraction of uranium and molybdenum in sulfuric media

    International Nuclear Information System (INIS)

    Duarte Neto, J.

    1980-01-01

    A Solvent extraction process for recovering the uranium and molibdenum from the sulfuric acid solution produced from Figueira ores was developed. The leach solution contains molibdenum with a mean ratio Mo/U = 35%. THe solvent used was a terciary amine-Alamine 336, modified with tridecanol in querosine. An investigation was made to evaluate the variables affecting the extraction and stripping of uranium and molibdenum. The Alamine 336 showed a significant extraction power for uranium and molibdenum. In the stripping step of uranium using acidified sodium cloride it was observed the presence of an insoluble amine-molibdenum-arsenic complex. (author) [pt

  13. Uranium extraction from sulfuric acid solution using anion exchange resin

    International Nuclear Information System (INIS)

    Sheta, M. E.; Abdel Aal, M. M.; Kandil, A. T.

    2012-12-01

    Uranium is currently recovered from sulfuric acid leach liquor using anion exchange resin as Amberlite IRA 402 (CT). This technology is based on fact that, uranium exists as anionic complexes. This takes place by controlling the pH of the solution, agitation time, temperature and resin to solution ratio (R/S). In this work, batch stirrer tank used for uranium extraction from sulfate medium and after extraction, elution process was done using 1M NaCl solution. After extraction and elution process, the resin was separated from the system and uranium was determined in the solution. (Author)

  14. Separation of uranium from molybdenum by alkyl phosphoric acid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Zhongshi, Li

    1986-08-01

    The regularities of separation of uranium from molybdenum by alkyl phosphoric acid extraction are described. Two parameters, i.e., density ratio of uranium to molybdenum in organic phase at first stage and density of uranium in raffinate at last stage are presented. The relationship between these parameters and purity of molybdenum and uranium products is given. The method of adjusting and controlling these parameters in experiments and production is worked out. The technical key problem in comprehensive utilization of sedimentary type uranium ore containing molybdenum with close concentration of these to elements has been solved.

  15. Refining of crude uranium by solvent extraction for production of nuclear pure uranium metal

    International Nuclear Information System (INIS)

    Gupta, S.K.; Manna, S.; Singha, M.; Hareendran, K.N.; Chowdhury, S.; Satpati, S.K.; Kumar, K.

    2007-01-01

    Uranium is the primary fuel material for any nuclear fission energy program. Natural uranium contains only 0.712% of 235 U as fissile constituent. This low concentration of fissile isotope in natural uranium calls for a very high level of purity, especially with respect to neutron poisons like B, Cd, Gd etc. before it can be used as nuclear fuel. Solvent extraction is a widely used technique by which crude uranium is purified for reactor use. Uranium metal plant (UMP), BARC, Trombay is engaged in refining of uranium concentrate for production of nuclear pure uranium metal for fabrication of fuel for research reactors. This paper reviews some of the fundamental aspects of this refining process with some special references to UMP, BARC. (author)

  16. Extracting Uranium from Seawater: Benefits, Risks and Policy Implication

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Aznan Fazli; Yim, Man-Sung; Marsh, Matthew [KAIST, Daejon (Korea, Republic of)

    2015-05-15

    One of the key issues that need to be addressed regarding the future of nuclear power is the availability of uranium. The most economical way to this day of providing uranium for nuclear energy has been through conventional mining. However, the current projection of the well-known, easily obtainable sources of uranium indicates that global nuclear industry can be supported through the end of the century under the once-through cycle. It, however, could be extended up to 250 years if the speculative uranium sources are taken into account. Uranium is also available in seawater. Extracting uranium from seawater has both pros and cons. The only main obstacles at this point is it not economically competitive compared to the conventional mining. Solving this issue will open up a new era of the way of extracting uranium to meet the future requirement of nuclear energy. As the uranium seawater extraction technology is rapidly being developed and might become feasible in the near future, an appropriate mechanism are required to safeguard the extraction technology.

  17. Development of Novel Sorbents for Uranium Extraction from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wenbin [Univ. of Chicago, IL (United States); Taylor-Pashow, Kathryn [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-01-08

    As the uranium resource in terrestrial ores is limited, it is difficult to ensure a long-term sustainable nuclear energy technology. The oceans contain approximately 4.5 billion tons of uranium, which is one thousand times the amount of uranium in terrestrial ores. Development of technologies to recover the uranium from seawater would greatly improve the uranium resource availability, sustaining the fuel supply for nuclear energy. Several methods have been previously evaluated including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons such as cost effectiveness, long term stability, and selectivity. Recent research has focused on the amidoxime functional group as a promising candidate for uranium sorption. Polymer beads and fibers have been functionalized with amidoxime functional groups, and uranium adsorption capacities as high as 1.5 g U/kg adsorbent have recently been reported with these types of materials. As uranium concentration in seawater is only ~3 ppb, great improvements to uranium collection systems must be made in order to make uranium extraction from seawater economically feasible. This proposed research intends to develop transformative technologies for economic uranium extraction from seawater. The Lin group will design advanced porous supports by taking advantage of recent breakthroughs in nanoscience and nanotechnology and incorporate high densities of well-designed chelators into such nanoporous supports to allow selective and efficient binding of uranyl ions from seawater. Several classes of nanoporous materials, including mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), meta-organic frameworks (MOFs), and covalent-organic frameworks (COFs), will be synthesized. Selective uranium-binding liagnds such as amidoxime will be incorporated into the nanoporous materials to afford a new generation of sorbent materials that will be

  18. Development of Novel Sorbents for Uranium Extraction from Seawater

    International Nuclear Information System (INIS)

    Lin, Wenbin; Taylor-Pashow, Kathryn

    2014-01-01

    As the uranium resource in terrestrial ores is limited, it is difficult to ensure a long-term sustainable nuclear energy technology. The oceans contain approximately 4.5 billion tons of uranium, which is one thousand times the amount of uranium in terrestrial ores. Development of technologies to recover the uranium from seawater would greatly improve the uranium resource availability, sustaining the fuel supply for nuclear energy. Several methods have been previously evaluated including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons such as cost effectiveness, long term stability, and selectivity. Recent research has focused on the amidoxime functional group as a promising candidate for uranium sorption. Polymer beads and fibers have been functionalized with amidoxime functional groups, and uranium adsorption capacities as high as 1.5 g U/kg adsorbent have recently been reported with these types of materials. As uranium concentration in seawater is only ~3 ppb, great improvements to uranium collection systems must be made in order to make uranium extraction from seawater economically feasible. This proposed research intends to develop transformative technologies for economic uranium extraction from seawater. The Lin group will design advanced porous supports by taking advantage of recent breakthroughs in nanoscience and nanotechnology and incorporate high densities of well-designed chelators into such nanoporous supports to allow selective and efficient binding of uranyl ions from seawater. Several classes of nanoporous materials, including mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), meta-organic frameworks (MOFs), and covalent-organic frameworks (COFs), will be synthesized. Selective uranium-binding liagnds such as amidoxime will be incorporated into the nanoporous materials to afford a new generation of sorbent materials that will be

  19. Physicochemical aspects of extraction of uranium concentrate from the wastes and thermodynamic characteristics of thorium-uranium compounds

    International Nuclear Information System (INIS)

    Khamidov, F.A.

    2017-01-01

    The purpose of present work is elaboration of physicochemical aspects of extraction of uranium concentrate from the wastes and study of thermodynamic characteristics of thorium-uranium compounds. Therefore, the radiological monitoring of tailing dumps of Tajikistan has been conducted; the obtaining of uranium concentrate from the tailing dumps of uranium production has been studied; the obtaining of uranium concentrate from the tailing dumps of uranium production with application of local sorbents has been studied as well; thermal stability and thermodynamic characteristics of uranium-thorium compounds has been investigated; the flowsheets of extraction of uranium concentrate from the wastes have been elaborated.

  20. Solvent extraction of uranium from high acid leach solution

    International Nuclear Information System (INIS)

    Ramadevi, G.; Sreenivas, T.; Navale, A.S.; Padmanabhan, N.P.H.

    2010-01-01

    A significant part of the total uranium reserves all over the world is contributed by refractory uranium minerals. The refractory oxides are highly stable and inert to attack by most of the commonly used acids under normal conditions of acid strength, pressure and temperature. Quantitative dissolution of uranium from such ores containing refractory uranium minerals requires drastic operating conditions during chemical leaching like high acid strength, elevated pressures and temperatures. The leach liquors produced under these conditions normally have high free acidity, which affects the downstream operations like ion exchange and solvent extraction

  1. Radiating toxicological and ecological consequences of extraction of uranium

    International Nuclear Information System (INIS)

    Svambaev, Z.A.; Svambaev, E.A.; Sultanbekov, G.A; Tusupbekova, S.T.

    2010-01-01

    In scientific work researchers take up questions of radiation, toxicity and ecological danger at extraction of natural uranium. In work it is resulted results of gauging of radiation in separate parts of a cycle, and also as a whole at underground extractions of uranium. The level of ionization actions of photon radiation in a radiating field with a productive solution which represents the big radiating, toxicological and ecological danger to Wednesday is shown on the average on cycles of feature of work.

  2. Uranium extraction from Uro area phosphate ore, Nuba mountains, Sudan

    International Nuclear Information System (INIS)

    Mohammed, A. A.; Eltayeb, M. A. H.

    2003-01-01

    This study was carried out mainly to extract uranium from Uro area phosphate ore in the eastern part of Nuba mountains near Abu Gibiha town in southern Kurdufan state. For this purpose first, the phosphate ore samples were decomposed with sulphuric acid. the resulting phosphoric acid was filtered off, and pretreated with pyrite and activated charcoal. the chemical analysis of the obtained grain phosphoric acid showed that about 98% of uranium content of the phosphate ore was rendered soluble in the phosphoric acid. The clear green phosphoric acid was introduced to uranium extraction by 25% tributylphosphate (Tbp) in kerosene. The effect of several factors on the extraction and stripping processes namely, interference's effect, the suitable strip solution, the required number of extraction and stripping stages, the optimum phase ratio have been studied in details. A three stage extraction at a phase ratio (aqueous/organic) of 1:2, followed by two stages stripping using 0.5 M sodium carbonate solution at a phase ratio (A/O) of 1:4 were found to be the optimum conditions to report more than 98% of uranium content in green phosphoric acid to the aqueous phase as uranyl tricarbonate complex (UO 2 (CO 3 ) 3 ) 4- . By applying sodica decomposition upon the stripping carbonate solution using 50% sodium hydroxide, about 98% of uranium content was precipitated as sodium diuranate concentrate (Na 2 U 2 O 7 ). The chemical analysis using atomic absorption spectrometry (Aas) showed a good agreement between the specification of the obtained uranium concentrate with the standard commercial specification of sodium diuranate concentrate. Further purification was achieved for the yellow cake by selective precipitation of uranium from the solution as uranium peroxide (UO 4 .2H 2 O) using 30% hydrogen peroxide. Finally the uranium peroxide precipitated was calcined at 450 degree C to obtain the orange powder uranium trioxide (UO 3 ). The chemical analysis of the final uranium trioxide

  3. Uranium

    International Nuclear Information System (INIS)

    1982-01-01

    The development, prospecting, research, processing and marketing of South Africa's uranium industry and the national policies surrounding this industry form the headlines of this work. The geology of South Africa's uranium occurences and their positions, the processes used in the extraction of South Africa's uranium and the utilisation of uranium for power production as represented by the Koeberg nuclear power station near Cape Town are included in this publication

  4. Chlorination of uranium ore for extraction of uranium, thorium and radium and for pyrite removal

    International Nuclear Information System (INIS)

    Skeaf, J.M.

    1979-01-01

    The high-temperature chlorination of uranium ore was investigated. The objective was to develop a process which is both economically viable and environmentally acceptable. Test work was directed toward obtaining high extractions of uranium, thorium and radium-226, as well as iron, sulphur and the rare earths, and consists of chlorinating samples of an Elliot Lake uranium ore at elevated temperatures and repulping the resulting calcine in dilute hydrochloric acid. The effect of temperature and chlorine throughput on the extraction of the various metals was investigated. The best conditions yielded extractions of uranium, iron and sulphur (all as chlorides) greater than 95 percent. Chlorine consumption varied between 6 and 16 percent by weight of the ore charge. (author)

  5. Extraction of uranium from seawater: a few facts

    Directory of Open Access Journals (Sweden)

    Guidez Joel

    2016-01-01

    Full Text Available Although uranium concentration in seawater is only about 3 micrograms per liter, the quantity of uranium dissolved in the world's oceans is estimated to amount to 4.5 billion tonnes of uranium metal (tU. In contrast, the current conventional terrestrial resource is estimated to amount to about 17 million tU. However, for a number of reasons the extraction of significant amounts of uranium from seawater remains today more a dream than a reality. Firstly, pumping the seawater to extract this uranium would need more energy than what could be produced with the recuperated uranium. Then if trying to use existing industrial flow rates, as for example on a nuclear power plant, it appears that the annual possible quantity remains very low. In fact huge quantities of water must be treated. To produce the annual world uranium consumption (around 65,000 tU, it would need at least to extract all uranium of 2 × 1013 tonnes of seawater, the volume equivalent of the entire North Sea. In fact only the great ocean currents are providing without pumping these huge quantities, and the idea is to try to extract even very partially this uranium. For example Japan, which used before the Fukushima accident about 8,000 tU by year, sees about 5.2 million tU passing every year, in the ocean current Kuro Shio in which it lies. A lot of research works have been published on the studies of adsorbents immersed in these currents. Then, after submersion, these adsorbents are chemically treated to recuperate the uranium. Final quantities remain very low in comparison of the complex and costly operations to be done in sea. One kilogram of adsorbent, after one month of submersion, yields about 2 g of uranium and the adsorbent can only be used six times due to decreasing efficiency. The industrial extrapolation exercise made for the extraction of 1,200 tU/year give with these values a very costly installation installed on more than 1000 km2 of sea with a

  6. Leaching and solvent extraction at Mary Kathleen Uranium Ltd

    International Nuclear Information System (INIS)

    Richmond, G.D.

    1978-01-01

    Mary Kathleen Uranium Ltd. recommenced operations in early 1976 following a twelve year period of care and maintenance. Several sections of the plant were modified or completely changed for the second operation. The most important change was the replacement of ion exchange with solvent extraction as the means of purifying and upgrading uranium rich solutions. Most of the problems experienced in the solvent extraction system originate from the leach liquor which has a strong tendency to form stable emulsions. This has been countered by some careful control of leaching conditions and by closer observation of operations in the solvent extraction area. Most problems have now been resolved and plant recoveries are quite satisfactory

  7. Extractive spectrophotometric determination of uranium with malachite green

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, S C; Nadkarni, M N [Bhabha Atomic Research Centre, Bombay (India). Fuel Reprocessing Div.

    1977-04-01

    A sensitive spectrophotometric method based on the extraction of a uranium-benzoate-Malachite Green complex by chlorobenzene is described. The absorption maximum is at 635 nm and the molar absorptivity is 8.3 x 10/sup 4/1. mole /sup -1/ cm/sup -1/. A preliminary separation of uranium by extraction with methyl isobutyl ketone from acid-deficient aluminium nitrate solution is used to avoid interferences. An aliquot of the extract in then diluted with chlorobenzene and shaken with benzoate buffer containing Malachite Green (MG). The method has been applied for the determination of uranium in a synthetic leach solution. The complex extracted is probably (U0/sub 2/(C/sub 6/H/sub 5/C00/sub 3//sup -/)(MG/sup +/).

  8. Extractive spectrophotometric determination of uranium with malachite green

    International Nuclear Information System (INIS)

    Dubey, S.C.; Nadkarni, M.N.

    1977-01-01

    A sensitive spectrophotometric method based on the extraction of a uranium-benzoate-Malachite Green complex by chlorobenzene is described. The absorption maximum is at 635 nm and the molar absorptivity is 8.3 x 10 4 1. mole -1 cm -1 . A preliminary separation of uranium by extraction with methyl isobutyl ketone from acid-deficient aluminium nitrate solution is used to avoid interferences. An aliquot of the extract in then diluted with chlorobenzene and shaken with benzoate buffer containing Malachite Green (MG). The method has been applied for the determination of uranium in a synthetic leach solution. The complex extracted is probably [U0 2 (C 6 H 5 C00 3 - ][MG + ]. (author)

  9. Extraction kinetics of uranium (VI) with polyurethane foam

    International Nuclear Information System (INIS)

    Huang, Ting-Chia; Chen, Dong-Hwang; Huang, Shius-Dong; Huang, Ching-Tsven; Shieh, Mu-Chang.

    1993-01-01

    The extraction kinetics of uranium(VI) from aqueous nitrate solution with polyether-based polyurethane foam was investigated in a batch reactor with automatic squeezing. The extraction curves of uranium(VI) concentration in solution vs. extraction time exhibited a rather rapid exponential decay within the first few minutes, followed by a slower exponential decay during the remaining period. This phenomenon can be attributed to the presence of two-phase structure, hard segment domains and soft segment matrix in the polyurethane foam. A two-stage rate model expressed by a superposition of two exponential curves was proposed, according to which the experimental data were fitted by an optimization method. The extraction rate of uranium (VI) was also found to increase with increasing temperature, nitrate concentration, and hydration of the cation of nitrate salt. (author)

  10. Process for extracting uranium from phosphoric acid solutions

    International Nuclear Information System (INIS)

    1977-01-01

    The description is given of a method for extracting uranium from phosphoric acid solutions whereby the previously oxided acid is treated with an organic solvent constituted by a mixture of dialkylphosphoric acid and trialkylphosphine oxide in solution in a non-reactive inert solvent so as to obtain de-uraniated phosphoric acid and an organic extract constituted by the solvent containing most of the uranium. The uranium is then separated from the extract as uranyl ammonium tricarbonate by reaction with ammonia and ammonium carbonate and the extract de-uraniated at the extraction stage is recycled. The extract is treated in a re-extraction apparatus comprising not less than two stages. The extract to be treated is injected at the top of the first stage. At the bottom of the first stage, ammonia is introduced counter current as gas or as an aqueous solution whilst controlling the pH of the first stage so as to keep it to 8.0 or 8.5 and at the bottom of the last stage an ammonium carbonate aqueous solution is injected in a quantity representing 50 to 80% of the stoichiometric quantity required to neutralize the dialkylphosphoric acid contained in the solvent and transform the uranium into uranyl ammonium tricarbonate [fr

  11. Studies on supercritical fluid extraction of uranium from sodium diuranate

    International Nuclear Information System (INIS)

    Prabhat, Parimal; Vithal, G.K.; Rao, Ankita; Kumar, Pradeep; Tomar, B.S.

    2014-01-01

    Crude sodium diuranate (SDU) produced from phosphoric acid by solvent extraction process with di-2-ethyl hexyl phosphoric acid (D2EHPA) and tri-n-butyl phosphate(TBP) contains iron and other rare earth impurities along with uranium. For further use of this uranium for fuel fabrication and its subsequent use in nuclear reactors, it has to be purified up to nuclear grade ammonium diuranate (ADU) specifications. Conventionally crude SDU is being purified by dissolving it in nitric acid followed by solvent extraction process using TBP in diluent. Use of large amount of acid and organic solvents for industrial processes is an environmental concern. Nowadays there are efforts to minimize use of acid and organic solvents in industrial processes. Supercritical Fluid Extraction (SFE) of uranium from different matrices (solid as well as liquid) has been reported by several authors in recent years. Near complete extraction of uranium from UO 2 (powder, green pellet and sintered pellet) using TBP-HNO 3 adduct by SFE has been reported. We attempted to explore possibility to purify crude SDU to nuclear grade by SFE of uranium from crude SDU matrix and study the effect of different operational parameters, mode of extraction and complexation

  12. Extraction of uranium low-grade ores from Great Divide Basin, Wyoming. National Uranium Resource Evaluation

    International Nuclear Information System (INIS)

    Judd, J.C.; Nichols, I.L.; Huiatt, J.L.

    1983-04-01

    The US Bureau of Mines is investigating the leachability of carbonaceous uranium ore samples submitted by the DOE under an Interagency Agreement. Studies on eight samples from the Great Divide Basin, Wyoming, are the basis of this report. The uranium content of the eight ore samples ranged from 0.003 to 0.03% U 3 O 8 and contained 0.7 to 45% organic carbon. Experiments were performed to determine the feasibility of extracting uranium using acid leaching, roast-acid leaching and pressure leaching techniques. Acid leaching with 600 lb/ton H 2 SO 4 plus 10 lb/ton NaClO 3 for 18 h at 70 0 C extracted 65 to 83% of the uranium. One sample responded best to a roast-leach treatment. When roasting for 4 h at 500 0 C followed by acid leaching of the calcine using 600 lb/ton H 2 SO 4 , the uranium extraction was 82%. Two of the samples responded best to an oxidative pressure leach for 3 h at 200 0 C under a total pressure of 260 psig; uranium extractions were 78 and 82%

  13. Extraction of uranium from seawater: a few facts - 5025

    International Nuclear Information System (INIS)

    Guidez, J.; Gabriel, S.

    2015-01-01

    Although uranium concentration in seawater is only about 3 micrograms/liter, the quantity of uranium dissolved in the world's oceans is estimated to amount to 4.5 billions tonnes of uranium metal (tU). In contrast, the current conventional terrestrial resource is estimated to amount to about 17 million tU. However, for a number of reasons the extraction of significant amounts of uranium from seawater remains today more a dream than a reality. Firstly, pumping the seawater to extract this uranium would need more energy more energy than what could be produced with the recuperated uranium. Then if trying to use existing industrial flow rates, as for example on a nuclear power plant, it appears that the annual possible quantity remains very low. In fact huge quantities of water must be treated. To produce the annual world uranium consumption (around 65.000 tU), it would need at least to extract all uranium of 2*10 13 tonnes of water, the volume equivalent to the entire North Sea. In fact only the great ocean currents are providing without pumping huge quantities of seawater and the idea is to try to extract even very partially this uranium. A lot of research works have been published, on the studies of adsorbents immersed in these currents. Then, after immersion, these adsorbents are chemically treated to recuperate the uranium. Final quantities remain low in comparison of the complex and costly operations to be done in sea. One kilogram of adsorbent, after one month of immersion, yields about 2 g of uranium and the adsorbent can only be used 6 times due to decreasing efficiency. The industrial extrapolation exercise made for the extraction of 1.200 tU/year give with these values a very costly installation installed on more than 1000 km 2 of sea with a lot of boats for transportation and maintenance. The ecological management of this huge installation would present significant challenges. (authors)

  14. Studies on extraction of uranium (VI) with petroleum sulfoxides

    International Nuclear Information System (INIS)

    Yang Yanzhao; Sun Sixiu; Bao Borong

    1999-01-01

    The extraction of uranium(VI) with petroleum sulfoxides(PSO) in different diluents is studied. The extraction ability of U(VI) decreases in the following order: benzene, toluene, cyclohexane, heptane, kerosene, carbon tetrachloride and chloroform. The influence of the concentrations of nitric acid, PSO, salting out agent, complexing anion and temperature on the extraction equilibrium is also investigated, and the enthalpy of the extraction reaction is obtained. The relationship between the extraction equilibrium constants K ex and the physical parameters of diluents is derived. The extraction mechanism and equilibrium are examined by measurement of IR spectrophotometry

  15. Uranium and Molybdenum extraction from a Cerro Solo deposit ore

    International Nuclear Information System (INIS)

    Becquart, Elena T.; Arias, Maria J.; Fuente, Juan C. de la; Misischia, Yamila A.; Santa Cruz, Daniel E.; Tomellini, Guido C.

    2009-01-01

    Cerro Solo, located in Chubut, Argentina, is a sandstone type uranium-molybdenum deposit. Good recovery of both elements can be achieved by acid leaching of the ore but the presence of molybdenum in pregnant liquors is an inconvenient to uranium separation and purification. A two steps process is developed. A selective alkaline leaching of the ore with sodium hydroxide allows separating and recovering of molybdenum and after solid-liquid separation, the ore is acid leached to recover uranium. Several samples averaging 0,2% uranium and 0,1% molybdenum with variable U/Mo ratio have been used and in both steps, leaching and oxidant reagents concentration, temperature and residence time in a stirred tank leaching have been studied. In alkaline leaching molybdenum recoveries greater than 96% are achieved, with 1% uranium extraction. In acid leaching up to 93% of the uranium is extracted and Mo/U ratio in solvent extraction feed is between 0,013 and 0,025. (author)

  16. ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

    Science.gov (United States)

    Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

    1957-11-12

    A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

  17. Oxidation-extraction of uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    Lawes, B.C.

    1985-01-01

    The invention involves an improvement to the reductive stripping process for recovering uranium values from wet-process phosphoric acid solution, where uranium in the solution is oxidized to uranium (VI) oxidation state and then extracted from the solution by contact with a water immiscible organic solvent, by adding sufficient oxidant, hydrogen peroxide, to obtain greater than 90 percent conversion of the uranium to the uranium (VI) oxidation state to the phosphoric acid solution and simultaneously extracting the uranium (VI)

  18. Extraction of Tetravalent Uranium by Certain Acidic Organophosphorus Extractants from Phosphate Medium

    International Nuclear Information System (INIS)

    Daoud, J.A.; Zeid, M.M.; Aly, H.F.

    1998-01-01

    The extraction of U(IV) by octylphenyl acid phosphate (OPAP) or di-2-ethylhexyl phosphoric acid (HDEHP) in kerosene from phosphoric acid was carried out. The effect of extractant, phosphoric acid, uranium, Fe(II) and Fe(III) concentration on the extraction process was separately investigated. The effect of different reagents and temperature on the stripping of U(IV) was also investigated. The results obtained for the extraction of U(IV) by HDEHP showed that the extraction with the increase in HDEHP and Fe(III) concentration while it decreases with the increase in phosphoric acid, uranium and Fe(II) concentration. In case of extraction with OPAP, the extraction of U(IV) was found to decrease with the phosphoric acid, Fe(II) and initial uranium concentration while the increase in OPAP concentration slightly affected the extraction. The use of high phosphoric acid concentration as stripper at low temperature was found to give the best stripping results

  19. Symposium 'geology, mining and extractive processing of uranium, with special reference to Europe'

    International Nuclear Information System (INIS)

    Pietsch, H.B.

    1977-01-01

    This review of the symposium 'Geology, mining and extractive processing of uranium' gives a survey from the point of view of ore processing rather than exploration. A reason for the uranium consumption assumed is given, and uranium deposits and availability, methods of exploration, and interesting facts on uranium extraction from ores are gone into. (HK) [de

  20. Extraction separation studies of uranium(VI) by amine oxides

    International Nuclear Information System (INIS)

    Ejaz, M.

    1975-01-01

    The extraction of uranium(VI) by two amine oxides, 4-(5-nonyl)pyridine oxide and trioctylamine oxide has been studied. The extraction behavior of these two N-oxides is compared. The dependence of extraction on the type of amine oxide and acid, nature of organic diluent, and amine oxide concentration has been investigated. The influence of the concentration of the metal and salting-out agents is described. The possible mechanism of extraction is discussed in the light of the results of extraction isotherms, loading radiodata, and log-log plots of amine oxide concentration vs distribution ratio. The separation factors for a number of metal ions are reported, and the separation of uranium from some fission elements has also been achieved

  1. Uranium extraction from high content chlorine leach liquor

    International Nuclear Information System (INIS)

    Fatemi, K.

    1998-01-01

    In this work uranium solution has been leached out by leaching process of uranium ores from Bandar-Ab bass port using sea water, since fresh water could not be available when it is processed in large scale. Two samples of different batches containing 11 and 20 gr./lit chlorine underwent two stages of precipitation by lead nitrate. As the result of this treatment the chlorine removed and its final concentration reduced to 530 p.p.m. which is well below allowances. Then, the uranium of this recent dechlorinated solu ton has been extracted by T.B.P. Uranium in organic phase was stripped out into inorganic phase by sodium carbonate and precipitated in a form of yellow cake and converted to U3o8. The total recovery of U, was well above 90% and the purity of the conc. U was better than 94%. The lead used at the beginning of the process was recovered for next use

  2. Extraction of uranium from sea water

    Energy Technology Data Exchange (ETDEWEB)

    Bals, H G [Uranerzbergbau G.m.b.H., Bonn (Germany, F.R.). Bereich Technik

    1979-04-01

    First tested on Helgoland in 1977, a test facility of the Uranerzbergbau GmbH, Bonn, is now about to start operation in the Golf Stream near the florida coast. At the present state of the art, the process is uneconomical unless uranium prices rise to several times the present level; however, the project management views the further developments quite optimistically. Commercial plants with a production up to 1,000 tons of uranium per year and more are already in the planning stage. In accordance with the Federal Minister for Research and Technology, who is acting as sponsor, another five year's plan to continue the project until 1983 has already been agreed upon.

  3. Enhancement of Extraction of Uranium from Seawater – Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Travis Cameron [Univ. of Maryland, College Park, MD (United States); Tsinas, Zois [Univ. of Maryland, College Park, MD (United States); Tomaszewski, Claire [Univ. of Maryland, College Park, MD (United States); Pazos, Ileana [Univ. of Maryland, College Park, MD (United States); Nigliazzo, Olga [University of Palermo, Palermo (Italy); Li, Weixing [Univ. of Maryland, College Park, MD (United States); Adel-Hadadi, Mohammad [Univ. of Maryland, College Park, MD (United States); Barkatt, Aaron [The Catholic Univ. of America, Washington, DC (United States); Al-Sheikhly, Mohamad [Univ. of Maryland, College Park, MD (United States)

    2016-05-16

    Even at a concentration of 3 μg/L, the world’s oceans contain a thousand times more uranium than currently know terrestrial sources. In order to take advantage of this stockpile, methods and materials must be developed to extract it efficiently, a difficult task considering the very low concentration of the element and the competition for extraction by other atoms in seawater such as sodium, calcium, and vanadium. The majority of current research on methods to extract uranium from seawater are vertical explorations of the grafting of amidoxime ligand, which was originally discovered and promoted by Japanese studies in the late 1980s. Our study expands on this research horizontally by exploring the effectiveness of novel uranium extraction ligands grafted to the surface of polymer substrates using radiation. Through this expansion, a greater understanding of uranium binding chemistry and radiation grafting effects on polymers has been obtained. While amidoxime-functionalized fabrics have been shown to have the greatest extraction efficiency so far, they suffer from an extensive chemical processing step which involves treatment with powerful basic solutions. Not only does this add to the chemical waste produced in the extraction process and add to the method’s complexity, but it also significantly impacts the regenerability of the amidoxime fabric. The approach of this project has been to utilize alternative, commercially available monomers capable of extracting uranium and containing a carbon-carbon double bond to allow it to be grafted using radiation, specifically phosphate, oxalate, and azo monomers. The use of commercially available monomers and radiation grafting with electron beam or gamma irradiation will allow for an easily scalable fabrication process once the technology has been optimized. The need to develop a cheap and reliable method for extracting uranium from seawater is extremely valuable to energy independence, and will extend the quantity of

  4. Enhancement of Extraction of Uranium from Seawater - Final Report

    International Nuclear Information System (INIS)

    Dietz, Travis Cameron; Tsinas, Zois; Tomaszewski, Claire; Pazos, Ileana; Nigliazzo, Olga; Li, Weixing; Adel-Hadadi, Mohammad; Barkatt, Aaron; Al-Sheikhly, Mohamad

    2016-01-01

    Even at a concentration of 3 μg/L, the world's oceans contain a thousand times more uranium than currently know terrestrial sources. In order to take advantage of this stockpile, methods and materials must be developed to extract it efficiently, a difficult task considering the very low concentration of the element and the competition for extraction by other atoms in seawater such as sodium, calcium, and vanadium. The majority of current research on methods to extract uranium from seawater are vertical explorations of the grafting of amidoxime ligand, which was originally discovered and promoted by Japanese studies in the late 1980s. Our study expands on this research horizontally by exploring the effectiveness of novel uranium extraction ligands grafted to the surface of polymer substrates using radiation. Through this expansion, a greater understanding of uranium binding chemistry and radiation grafting effects on polymers has been obtained. While amidoxime-functionalized fabrics have been shown to have the greatest extraction efficiency so far, they suffer from an extensive chemical processing step which involves treatment with powerful basic solutions. Not only does this add to the chemical waste produced in the extraction process and add to the method's complexity, but it also significantly impacts the regenerability of the amidoxime fabric. The approach of this project has been to utilize alternative, commercially available monomers capable of extracting uranium and containing a carbon-carbon double bond to allow it to be grafted using radiation, specifically phosphate, oxalate, and azo monomers. The use of commercially available monomers and radiation grafting with electron beam or gamma irradiation will allow for an easily scalable fabrication process once the technology has been optimized. The need to develop a cheap and reliable method for extracting uranium from seawater is extremely valuable to energy independence, and will extend the

  5. Rirang uranium ore processing: continuous solvent extraction of uranium from Rirang ore acid digestion solution

    International Nuclear Information System (INIS)

    Riza, F.; Nuri, H. L.; Waluya, S.; Subijanto, A.; Sarono, B.

    1998-01-01

    Separation of uranium from Rirang ore acid digestion solution by means of continuous solvent extraction using mixer-settlers has been studied and a mixture of 0.3 M D2EHPA and 0.075 M TOPO extracting agent and kerosene diluent is employed to recover and separate uranium from Th, RE, phosphate containing solution. The experiments have been conducted batch-wise and several parameters have been studied including the aqueous to organic phase ratio, A/O, the extraction and the stripping times, and the operation temperature. The optimum conditions for extraction have been found to be A/O = 2 ratio, five minute extraction time per stage at room temperature. The uranium recovery of 99.07% has been achieved at those conditions whilst U can be stripped from the organic phase by 85% H 3 PO 4 solution with an O/A = 1 for 5 minutes stripping time per stage, and in a there stage operation at room temperature yielding a 100% uranium recovery from the stripping process

  6. Separation of uranium by extraction with foamed plastics

    International Nuclear Information System (INIS)

    Korkisch, J.

    1983-07-01

    Polyurethane foams are frequently used for the extraction and separation of inorganic and organic species. The attraction of the materials lies in their favourable hydrodynamic properties obviating the need for the forced-flow conditions associated with conventional chromatographic-type column packing of small particles. The research work described has been directed to providing information on the extraction and separation of uranium (and thorium) by an open-cell polyurethane foam from media containing nitrates and from hydrochloric acid systems. The influence of many different experimental parameters (concentrations, acidity, impregnation of the foam with organic extractants) on the extraction was investigated. Based on the results of these investigations two methods were developed to separate uranium from nitric acid solution and from hydrochloric acid solution, respectively. The first uses calcium or aluminium nitrate salting and foam impregnated with Aliquat 336, the second ascorbic acid addition and TOPO-impregnated foam. The methods separate uranium and thorium from each other and from most other elements and can be used analytically or in the purification of uranium from impure plant products such as yellow cake

  7. Rapid extraction and assay of uranium from environmental surface samples

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Christopher A.; Chouyyok, Wilaiwan; Speakman, Robert J.; Olsen, Khris B.; Addleman, Raymond Shane

    2017-10-01

    Extraction methods enabling faster removal and concentration of uranium compounds for improved trace and low-level assay are demonstrated for standard surface sampling material in support of nuclear safeguards efforts, health monitoring, and other nuclear analysis applications. A key problem with the existing surface sampling swipes is the requirement for complete digestion of sample and sampling matrix. This is a time-consuming and labour-intensive process that limits laboratory throughput, elevates costs, and increases background levels. Various extraction methods are explored for their potential to quickly and efficiently remove different chemical forms of uranium from standard surface sampling material. A combination of carbonate and peroxide solutions is shown to give the most rapid and complete form of uranyl compound extraction and dissolution. This rapid extraction process is demonstrated to be compatible with standard inductive coupled plasma mass spectrometry methods for uranium isotopic assay as well as screening techniques such as x-ray fluorescence. The general approach described has application beyond uranium to other analytes of nuclear forensic interest (e.g., rare earth elements and plutonium) as well as heavy metals for environmental and industrial hygiene monitoring.

  8. Extractants for uranium recovery from wet phosphoric acid

    International Nuclear Information System (INIS)

    Musikas, C.; Benjelloun, N.; Lours, S.

    1981-08-01

    It must be pointed out that despite their lower affinity for uranyl, the dialkyldithiophosphates show higher extraction coefficients than dialkylphosphates. In addition, it is possible to back extract uranium with oxalate solutions at pH levels where the solvents remain in their acidic form. This last possibility seems to be correlated with the presence of a H 2 PO 4 - ion in the U(VI) organic complexes

  9. Heap leaching procedure for the Uranium extraction

    International Nuclear Information System (INIS)

    Shishahbore, M. R.

    2002-01-01

    Heap leaching of Uranium ores is currently in use in several countries. Before taking any decision for construction of heap in industrial scale, it is necessary to obtain the main factors that influence the heap leaching process, such as acid construction, acid solution flowrate, temperature of reaction, or size, ration of liquid to solid, permeability and suitable oxidant. To achieve the above parameters, small scale column leaching is usually recommended. In this project column leaching were carried out in 6 plexiglass column with 43.5 cm an height and 7.4 cm inner diameter. In each column closely 2.00 kg Uranium ore were leached by sulfuric acid. Leaching operation on Iranian ores from two different anomalies from the same area were investigated. In this project, six column were leached at different flowrate of eluent and effect of oxidant were investigated. Acid consumption were in the range of 60 - 144 kg per ton ore and recovery between 73.07% - 99.97%. Finally according to the results obtained, investigated that over are suitable to heap leaching technique. Al tough, to enforce of heap leaching project need to more experiments

  10. Rehabilitation work after chemical extraction of uranium

    International Nuclear Information System (INIS)

    Rychtarik, T.

    2003-01-01

    In the past, uranium was mined from the Straz pod Ralskem deposit by leaching with sulfuric acid in a very environmentally unfriendly manner. Rehabilitation work, which is in progress, aims to reduce the concentration of contaminants in the Cenomanian and Turonian groundwater bodies to an acceptable level. The rehabilitation project was divided into 2 stages: (1) prevention of vertical diffusion of contamination into unaffected areas by creating a sub-balance of solutions, and (2) sub-balance of solutions in combination with a processing of the contaminants and reduction of the contamination level to a preset value. Among the crucial provisions is the operation of the SLKR I evaporator where the solution, previously freed from uranium, is processed into condensate which is drained into the Ploucnice river, concentrated solution which, after dilution, is returned to the leaching fields, crystalline alum, and mother liquors. The production of alum has been increasing since 2002 and its reprocessing to aluminium sulfate is in the trial stage. Rehabilitation of the Turonian groundwater body is a challenge. Sanitation targets have been set till 2010. (P.A.)

  11. Extraction of uranium by hydroxybenzamide type polymers

    International Nuclear Information System (INIS)

    Sakuragi, Masako; Ichimura, Kunihiro; Suda, Yoshio; Marumo, Tomofuyu; Iwaki, Takao; Abe, Yoshimoto; Misono, Takahisa.

    1985-01-01

    Polyethyleneimine crosslinked with N,N'-methylenebisacrylamide was treated with substituted phenyl hydroxybenzoates to give the polymers having corresponding hydroxybenzamide groups. In these polymers I-V, polymer having 2-hydroxybenzamide group (I) and that having 2,4-dihydroxybenzamide group (II) showed the adsorption abilities of 45 and 87 μg-U/g in 4 days in seawater, respectively. The polymers having 2-hydroxybenzamide group in concentration from 1 to 20 mol % were prepared and the adsorption property for uranium was examined. Three mol % is most suitable concentration for treatment for 2-4 days, while 20 mol % is suitable for treatment for 30 days. The polymer prepared from porous polyethyleneimine bead showed higher adsorption ability than usual ones. (J.P.N.)

  12. Technical progress review of extraction of uranium from fly ash

    International Nuclear Information System (INIS)

    Gao Renxi; Gao Junning; Wu Qingming; Chen Gang; Wan Hongjin; Zhang Ziyue

    2014-01-01

    The increasing of fly ash in coal-fired power plants at home and abroad year by year and the potential impacts to the environment attracted media attention. Although the extraction of uranium from the fly ash in coal-fired power plants had optional process from technique aspect and sufficient preliminary researches, but considering the low grade of the uranium in fly ash and particularity of the mineral composition, it is easy to have a high cost of extraction. As a consequence, it is not included in the development plan of uranium mining and metallurgy. The present applications of fly ash are only building materials, building roads and pit valley backfill, the resource utilization rate was low and was still in its early stages of development and application. In view of this, the research advances and the latest development trends of extraction of uranium from fly ash at home and abroad were introduced from the technical aspect, and the beneficial analyzes of the prospect and advices to this industry were given. (authors)

  13. Extraction of uranium from seawater: evaluation of uranium resources and plant siting

    Energy Technology Data Exchange (ETDEWEB)

    Rodman, M.R.; Gordon, L.I.; Chen, A.C.T.

    1979-02-01

    This report deals with the evaluation of U.S. coastal waters as a uranium resource and with the selection of a suitable site for construction of a large-scale plant for uranium extraction. Evaluation of the resource revealed that although the concentration of uranium is quite low, about 3.3 ppB in seawater of average oceanic salinity, the amount present in the total volume of the oceans is very great, some 4.5 billion metric tons. Of this, perhaps only that uranium contained in the upper 100 meters or so of the surface well-mixed layer should be considered accessible for recovery, some 160 million tonnes. The study indicated that open ocean seawater acquired for the purpose of uranium extraction would be a more favorable resource than rivers entering the sea, cooling water of power plants, or the feed or effluent streams of existing plants producing other products such as magnesium, bromine, or potable and/or agricultural water from seawater. Various considerations led to the selection of a site for a pumped seawater coastal plant at a coastal location. Puerto Yabucoa, Puerto Rico was selected. Recommendations are given for further studies. 21 figures, 8 tables.

  14. Extraction of uranium from seawater: evaluation of uranium resources and plant siting

    International Nuclear Information System (INIS)

    Rodman, M.R.; Gordon, L.I.; Chen, A.C.T.

    1979-02-01

    This report deals with the evaluation of U.S. coastal waters as a uranium resource and with the selection of a suitable site for construction of a large-scale plant for uranium extraction. Evaluation of the resource revealed that although the concentration of uranium is quite low, about 3.3 ppB in seawater of average oceanic salinity, the amount present in the total volume of the oceans is very great, some 4.5 billion metric tons. Of this, perhaps only that uranium contained in the upper 100 meters or so of the surface well-mixed layer should be considered accessible for recovery, some 160 million tonnes. The study indicated that open ocean seawater acquired for the purpose of uranium extraction would be a more favorable resource than rivers entering the sea, cooling water of power plants, or the feed or effluent streams of existing plants producing other products such as magnesium, bromine, or potable and/or agricultural water from seawater. Various considerations led to the selection of a site for a pumped seawater coastal plant at a coastal location. Puerto Yabucoa, Puerto Rico was selected. Recommendations are given for further studies. 21 figures, 8 tables

  15. Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction

    International Nuclear Information System (INIS)

    Phillips, E.J.P.; Landa, E.R.; Lovley, D.R.

    1995-01-01

    A process for concentrating uranium from contaminated soils in which the uranium is first extracted with bicarbonate and then the extracted uranium is precipitated with U(VI)-reducing microorganisms was evaluated for a variety of uranium-contaminated soils. Bicarbonate (100 mM) extracted 20-94% of the uranium that was extracted with nitric acid. The U(VI)-reducing microorganism, Desulfovibrio desulfuricans reduced the U(VI) to U(IV) in the bicarbonate extracts. In some instances unidentified dissolved extracted components, presumably organics, gave the extract a yellow color and inhibited U(VI) reduction and/or the precipitation of U(IV). Removal of the dissolved yellow material with the addition of hydrogen peroxide alleviated this inhibition. These results demonstrate that bicarbonate extraction of uranium from soil followed by microbial U(VI) reduction might be an effective mechanism for concentrating uranium from some contaminated soils. (author)

  16. The technology of uranium extraction from the brine with high chlorine-ion content

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.; Negmatov, Sh.I.; Barotov, B.B.

    2010-01-01

    Present article is devoted to technology of uranium extraction from the brine with high chlorine-ion content. The research results on uranium extraction from the brine of Sasik-Kul Lake by means of sorption method were considered. The chemical composition of salt was determined. The process of uranium sorption was described and analyzed. The technology of uranium extraction from the brine with high chlorine-ion content was proposed.

  17. Selected bibliography for the extraction of uranium from seawater: evaluation of uranium resources and plant siting

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A.C.T.; Gordon, L.I.; Rodman, M.R.; Binney, S.E.

    1979-02-06

    This bibliography contains 471 references pertaining to the evaluation of U.S. territorial ocean waters as a potential uranium resource and to the selection of a site for a plant designed for the large scale extraction of uranium from seawater. This bibliography was prepared using machine literature retrieval, bibliographic, and work processing systems at Oregon State University. The literature cited is listed by author with indices to the author's countries, geographic areas of study, and to a set of keywords to the subject matter.

  18. Selected bibliography for the extraction of uranium from seawater: evaluation of uranium resources and plant siting

    International Nuclear Information System (INIS)

    Chen, A.C.T.; Gordon, L.I.; Rodman, M.R.; Binney, S.E.

    1979-01-01

    This bibliography contains 471 references pertaining to the evaluation of U.S. territorial ocean waters as a potential uranium resource and to the selection of a site for a plant designed for the large scale extraction of uranium from seawater. This bibliography was prepared using machine literature retrieval, bibliographic, and work processing systems at Oregon State University. The literature cited is listed by author with indices to the author's countries, geographic areas of study, and to a set of keywords to the subject matter

  19. Comprehension of synergistic mechanisms for uranium extraction from phosphate ores

    International Nuclear Information System (INIS)

    Pecheur, Olivia

    2014-01-01

    Uranium VI is commonly extracted from phosphoric ores by a well-known process exploiting the synergistic mixture of two extractant molecules: HDEHP and TOPO. In the field of liquid-liquid extraction, synergistic combinations are common but the mechanisms at the origin of the synergy are not well understood. A multi-scale approach has been used to describe these mechanisms, combining two different descriptions: the molecular scale focuses on the ion point of view, while the supramolecular scale focuses on extractants' aggregation. These two approaches have been rationalized by molecular dynamics computations. The results allow describing the synergy through the structure of the complexes and aggregates. With the same approach, some bifunctional compounds, combining the two extracting sites in one molecule, have been studied and compared to the HDEHP/TOPO system in order to identify the origin of their increased capacities in extraction and selectivity. (author) [fr

  20. Fuel Cycle Impacts of Uranium-Plutonium Co-extraction

    International Nuclear Information System (INIS)

    Taiwo, Temitope; Szakaly, Frank; Kim, Taek-Kyum; Hill, Robert

    2008-01-01

    A systematic investigation of the impacts of uranium and plutonium co-extraction during fuel separations on reactor performance and fuel cycle has been performed. Proliferation indicators, critical mass and radiation source levels of the separation products or fabricated fuel, were also evaluated. Using LWR-spent-uranium-based MOX fuel instead of natural-uranium-based fuel in a PWR MOX core requires a higher initial plutonium content (∼1%), and results in higher Np-237 content (factor of 5) in the spent fuel, and less consumption of Pu-238 (20%) and Am-241 (14%), indicating a reduction in the effective repository space utilization. Additionally, minor actinides continue to accumulate in the fuel cycle, and thus a separate solution is required for them. Differences were found to be quite smaller (∼0.4% in initial transuranics) between the equilibrium cycles of advanced fast reactor cores using spent and depleted uranium for make-up, in additional to transuranics. The critical masses of the co-extraction products were found to be higher than for weapons-grade plutonium (WG-Pu) and the decay heat and radiation sources of the materials (products) were also found to be generally higher than for WG-Pu in the transuranics content range of 10% to 100% in the heavy-metal. (authors)

  1. Supercritical fluid extraction of uranium and thorium employing dialkyl amides

    International Nuclear Information System (INIS)

    Rao, Ankita; Kumar, Pradeep

    2014-01-01

    Extraction and purification of actinides from different matrices is of utmost importance to the nuclear industry. In recent decades, supercritical fluid extraction (SFE) has emerged as a promising alternative to solvent extraction owing to its inherent potential of minimization of liquid waste generation. N,N-dialkyl aliphatic amides have been proposed to be an alternative to TBP in the reprocessing of spent nuclear fuel due to several attractive features like innocuous nature of degradation products (mainly carboxylic acids/ amines), possibility of complete incineration of the used extractant leading to reduction in volume of secondary waste. Also, physico-chemical properties of this class of extractants can be tuned by the judicious choice of alkyl groups. In the present work, N,N-dialkyl aliphatic amides with varying alkyl groups viz. N,N-dibutyl-2-ethylhexanamide (DBEHA), N,N-dibutyl-3,3-dimethylbutanamide (DBDMBA), N,N-dihexyloctanamide (DHOA), N,N-disecbutylpentamide (DBPA), N,N-dibutyloctanamide (DBOA), have been evaluated for supercritical fluid extraction (SFE) of uranium and thorium from nitric acid medium as well as tissue paper matrix. Amides were obtained from Department of Chemistry, Delhi University and were used as such. This fact could be exploited for separation of thorium and uranium

  2. Study on the uranium-cerium extraction and his application to the treatment of irradiated uranium

    International Nuclear Information System (INIS)

    Lobao, Afonso dos Santos Tome

    1979-01-01

    It was made a study on the behavior of uranium and cerium(IV) extraction, using the latter element as a plutonium simulator in a flowsheet of the treatment of irradiated uranium. Cerium(IV) was used under the same conditions as a plutonium in the Purex process because the admitted similar properties. An experimental work was initiated to determine the equilibrium curves of uranium, under the following conditions: concentration of 1 to 20 g U/1 and acidity varying from 1 to 5M in HNO 3 . Other parameters studied were the volumetric ratio of the phases and the influence of the concentration of TBP (tri-n-butyl phosphate). To guarantee the cerium(IV) extraction, the diluent (varsol) was previously treated with 10% potassium dichromate in perchloric acid, potassium permanganate in 1M sulphuric acid and concentrated sulphuric acid at 70 deg to eliminate reducing compounds. The results obtained for cerium extraction, allowed a better understanding of its behavior in solution. The results permitted to conclude that the decontamination for cerium are very high in the first Purex extraction cycle. The easy as cerium(IV) is reduced to the trivalent state contributes a great deal to its decontamination. (author)

  3. Proceedings of the meeting on uranium exploration, mining and extraction

    International Nuclear Information System (INIS)

    1996-01-01

    Meeting on uranium exploration, mining, and extraction is aimed to expedite information exchange among researchers from the National Atomic Energy Agency (BATAN), their international colleagues, the higher education institutions,and other interested scientific communities on the latest development on Kalan uranium minerals exploration, mining, and extraction. Nuclear Minerals Development Centre (PPBGN) roles in nuclear energy provision, the theme of the meeting, reflect current advancements of the Centre in fulfilling its major tasks and responsibilities. In order to assist PPBGN better to assume its roles and responsibilities, the meeting is expected to bring forth essential solutions for problems and difficulties relevant to PPBGN's activities. Hence, the scope of the meeting will be limited to discussion on the status of nuclear minerals exploration, mining, and extraction technologies in Indonesia as well as the related environmental and workplace safeties in uranium mining and milling. Ten technical papers were presented in meeting, including four topics on exploration status and technology, three subject matter on mining, two presentations on milling, and one paper on environmental and workplace safeties

  4. Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction

    Science.gov (United States)

    Philips , Elizabeth J.P.; Landa, Edward R.; Lovely, Derek R.

    1995-01-01

    A process for concentrating uranium from contaminated soils in which the uranium is first extracted with bicarbonate and then the extracted uranium is precipitated with U(VI)-reducing microorganisms was evaluated for a variety of uranuum-contaminated soils. Bicarbonate (100 mM) extracted 20–94% of the uranium that was extracted with nitric acid. The U(VI)-reducing microorganism,Desulfovibrio desulfuricans reduced the U(VI) to U(IV) in the bicarbonate extracts. In some instances unidentified dissolved extracted components, presumably organics, gave the extract a yellow color and inhibited U(VI) reduction and/or the precipitation of U(IV). Removal of the dissolved yellow material with the addition of hydrogen peroxide alleviated this inhibition. These results demonstrate that bicarbonate extraction of uranium from soil followed by microbial U(VI) reduction might be an effective mechanism for concentrating uranium from some contaminated soils.

  5. Extraction of uranium from simulated ore by the supercritical carbon dioxide fluid extraction method with nitric acid-TBP complex

    International Nuclear Information System (INIS)

    Dung, Le Thi Kim; Imai, Tomoki; Tomioka, Osamu; Nakashima, Mikio; Takahashi, Kuniaki; Meguro, Yoshihiro

    2006-01-01

    The supercritical fluid extraction (SFE) method using CO 2 as a medium with an extractant of HNO 3 -tri-n-butyl phosphate (TBP) complex was applied to extract uranium from several uranyl phosphate compounds and simulated uranium ores. An extraction method consisting of a static extraction process and a dynamic one was established, and the effects of the experimental conditions, such as pressure, temperature, and extraction time, on the extraction of uranium were ascertained. It was found that uranium could be efficiently extracted from both the uranyl phosphates and simulated ores by the SFE method using CO 2 . It was thus demonstrated that the SFE method using CO 2 is useful as a pretreatment method for the analysis of uranium in ores. (author)

  6. Extraction and determination of hydrogen in uranium and zirconium

    International Nuclear Information System (INIS)

    Champeix, L.; Coblence, G.; Darras, R.

    1959-01-01

    The method of desorption under vacuum at high temperatures in the solid phase, which gives good results in the case of steels, has been applied to uranium and zirconium. In these two metals hydrogen is found mainly in the form of hydride. It is chiefly a question of determining the most suitable temperature and the heating time necessary to obtain an almost total extraction of hydrogen. Two considerations must be taken into account in the choice of temperature. It should be such that on the one hand the hydride decomposes rapidly and completely at the reduced pressure applied, and on the other hand the diffusion of hydrogen through the metal takes place fairly quickly. The apparatus and the method used are described; systematic tests have led to the adoption of temperatures of 650 deg. C for uranium and 1050 deg. C for zirconium. (author) [fr

  7. Development of Speciality polymer to extract uranium from sea water

    International Nuclear Information System (INIS)

    Tabushi, Iwao

    1983-01-01

    Polymer adsorbents were designed to extract uranium efficiently from sea water. The unique coordination structure of uranyl ion was suggested from x-ray crystallography and determining factors influencing equilibrium constants were elucidated. A quantitative estimation of the ligand efficiency was obtained. Based on these considerations on the coordination chemistry of uranyl ion, new polymer adsorbents were prepared and found to show excellent adsorption characteristics. The macrocyclic ligands mimicking crystallographic structure of the complex: planer headentate, were found to show large equilibrium constants as well as high selectivities toward metal ions. Direct usage of sea current was proposed as a most economical way of treating a huge amount of sea water. The polymer adsorbent could recover uranium with large adsorption rate just by immersing the resin into Kuroshio. (author)

  8. Specific chelating reagent to extract uranium from the sea water

    International Nuclear Information System (INIS)

    Tabushi, Iwao; Kobuke, Yoshiaki

    1982-01-01

    The behavior of uranyl ions as seen from the chemistry of complex as the object of molecule recognition was examined on the basis of the research of structure and equilibrium in solution, in an attempt for the search of specific ligands and the molecular design of adsorbents. What is the most essential for the extraction of uranyl ions from sea water is the development of an excellent adsorbent with rapid adsorption, large equilibrium adsorption and high physical-chemical stability. Based on this appreciation, attempt has been made to find out the molecular design of an excellent adsorbent, starting with the chemistry of complex of uranyl ions. For the purpose, the following matters are reviewed: uranium in nature, the chemistry of complex of uranyl ions, specific ligands for the uranyl ions in sea water, the adsorbent resins for sea-water uranium, the proposals for an adsorbent system. (Mori, K.)

  9. Uranium Rirang ore processing: extraction of uranium from Rirang ore digestion solution with tributyl phosphate

    International Nuclear Information System (INIS)

    Arief, E. R.; Zahardi; Susilaningtyas

    1998-01-01

    Uranium is extracted from Rirang ore acid digestion solution containing rare earths. A mixture of tributyl phosphate solvent and kerosene diluent is employed. Several parameters of solvent extraction have been studied included aqueous to organic phase ratio, H 2 O 2 reductor concentration and Tbp concentration in the solvent mixture, as well as the aqueous to organic phase ratio in the stripping process. The optimum conditions for the extraction step include the use of 25% H 2 O 2 (v/v), one to one aqueous to organic ratio, and 40% Tbp in kerosene. The extraction recovery for U, RE, Th, and PO 4 3 - are 99%, 4%, 70%, and 30%, respectively. The stripping step optimum conditions include the use of one to five organic to aqueous phase ratio 0.24 N HNO 3 . and the stripping recovery for U, RE, Th, and PO 4 3 - are 84%, 80%, 72%, and 83%, respectively

  10. Studies on the extraction of uranium by N-octanoyl-N-phenylhydroxamic acid

    International Nuclear Information System (INIS)

    Saha, B.; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R.; Natarajan, R.

    2002-01-01

    N-octanoyl-N-phenylhydroxamic acid (OHA) has been prepared by partial reduction of nitrobenzene with Zn dust/NH 4 Cl, followed by acylation with n-octanoyl chloride. Structure of OHA was confirmed by 1 H NMR, IR spectra and CHNS microanalysis. The extraction of uranium by OHA has been studied as a function of pH, temperature and concentration of OHA. The extraction of uranium was found to increase with increase in pH. Uranium forms a 1 : 2 complex with OHA. IR Spectra and NMR Spectra of the uranium-OHA complex and slope analysis obtained from extraction studies indicated that the extraction of uranium was due to the formation of a chelate. The enthalpy change accompanied by the extraction of uranium by OHA has been obtained by temperature variation method. The extraction process was found to be endothermic at pH 2 and exothermic at pH 6. (orig.)

  11. Modifier free supercritical fluid extraction of uranium from sintered UO2, soil and ore samples

    International Nuclear Information System (INIS)

    Kanekar, A.S.; Pathak, P.N.; Acharya, R.; Mohapatra, P.K.; Manchanda, V.K.

    2011-01-01

    Direct extraction of uranium from different samples viz. sintered UO 2 , soil and ores was carried out by modifier free supercritical fluid using tri-n-butyl phosphate-nitric acid (TBP-HNO 3 ) adduct as extractant. These studies showed that pre-equilibration with more concentrated nitric acid helps in better dissolution and extraction of uranium from sintered UO 2 samples. Modifier free supercritical fluid extraction appears attractive with respect to minimization of secondary wastes. This method resulted 80-100% extraction of uranium from different soil/ore samples. The results were confirmed by performing neutron activation analysis of original (before extraction) and residue (after extraction) samples. (author)

  12. Membrane extraction in preconcentration of some uranium fission products

    International Nuclear Information System (INIS)

    Macasek, F.; Rajec, P.; Kopunec, R.; Mikulaj, V.

    1984-01-01

    Theoretical comparison of the equilibria and kinetics of solvent extraction (SX) and emulsion liquid membrane extraction (MX) was performed using the distribution ratios at the outer inner boundaries of liquid membrane. Enhancement factors, pertraction factor (p) and mulitplication factor (N), were proposed to express efficiency of the MX technique. The extraction of cesium, strontium, cobalt(II), uranium(VI), cerium(III) and technetium(VII) was investigated from this point of view. The most perspective systems are those with chelating agents (e.g. di-2-ethylhexyl-phosporic acid and 8-hydroquinoline), especially at low concentrations (substioichiometric amounts), with which high enhancement factors can be achieved. The results with the ion-exchange systems (bis(1,2-dicarbollyl)-cobalt(III) and quaternary ammonium salts) may be interpreted as indicating some surface barriers which prevent the transport of ions. 20 references, 14 figures, 6 tables

  13. Scale-up of mixer-settler for uranium extraction

    International Nuclear Information System (INIS)

    Santana, A.O. de.

    1990-05-01

    The aim of this work was to obtain scale-up relations for a box type mixer-settler used in uranium extraction process for chloridric leaches. Three box type units with different sizes and with the same geometry were used for scale-up of the mixer. The correlation between extraction rate and specific power input, D/T ratio (stirrer diameter/mixer length) and residence time were experimentally obtained. The results showed that the extraction increases with power input for a constant value of D/T equal to 1/3, remaining however independent from mixer sizes for a specific value of power input. This behavior was observed for power input values ranging from 100 to 750 w/m 9 . (author). 23 refs, 22 figs, 23 tabs

  14. Detection of uranium extraction zone by axial temperature profiles in a pulsed column for Purex process

    International Nuclear Information System (INIS)

    Tsukada, T.; Takahashi, K.

    1991-01-01

    A new method was presented for detecting uranium extraction zone in a pulsed column by means of measuring axial temperature profile originated from reaction heat during uranium extraction. Key parameters of the temperature profiles were estimated with a code developed for calculating temperature profiles in a direct-contact heat exchanger such as a pulsed column, and were verified using data from a small pulsed column simulating reaction heat with injecting hot water. Finally, the results were compared with those from an actual uranium extraction tests, indicating that the method presented was promising for detecting uranium extraction zone in a pulsed column. (author)

  15. Determination of nitrate in effluents from Uranium Extraction Plant

    International Nuclear Information System (INIS)

    Dudwadkar, Ayushi; Kumar, Sangita D.; Reddy, A.V.R.

    2014-01-01

    Determination of nitrate concentration in the effluent samples from Uranium Extraction Plant is required before its safe discharge. As the different streams are diluted with sea water these samples contain high concentration of chloride. The large concentration of chloride poses a challenge in the determination of nitrate; hence, matrix elimination is accomplished by adopting a sample pretreatment technique. The present study was carried out to develop a simple, accurate and rapid analytical methodology for the determination of nitrate in the above matrices. The quantitative determination of nitrate was accomplished using anion exchange chromatography with conductometric detection. (author)

  16. Using geoelectrochemical technique to extract uranium and other metals

    International Nuclear Information System (INIS)

    Gao Yulong

    1990-10-01

    The geoelectrochemical extraction technique, which is a direct deep exploring method, is one of the geoelectrochemical exploring methods. It is developed recently to explore basic metals, precious metals, rare metals and some nonmetal mineral products. It is also a combination of electrical surveying and geochemical surveying. This method is more useful in the seeking of gold ore deposit. The principle and technique of this method and the results in seeking gold, uranium, lead, nickel and tin ore deposits are introduced. The equipment and instruments used in this method are also given

  17. Uranium Extraction from Phosphates: - Background, Opportunities, Process Overview & Way Forward for Commercialisation

    International Nuclear Information System (INIS)

    Tulsidas, Harikrishnan; Hilton, Julian; Kumar Haldar, Tapan

    2014-01-01

    Uranium Extraction from Phosphate - an attractive proposition: • Uranium is co-product of phosphate Industry and makes phosphate Industry economically viable & socially more acceptable; • Enable utilisation of mineral deposits having low Phosphate value through economic co-production of Phosphatic fertiliser & Uranium; • Bring new countries in global map of Uranium resources; • Enables socio-economic up-gradation of major part of global population by achieving Energy, food & Environmental security - so important in today’s scenario

  18. Extraction equilibrium of uranium(VI) with dicyclohexano-18-crown-6 and its application for separating uranium and thorium

    International Nuclear Information System (INIS)

    Wang Wenji; Sun Quing; Chen Bozhong

    1986-01-01

    The extraction of uranium with dicyclohexano-18-crown-6 (mixed isomers) is described. The extraction equilibrium of uranium(VI) from aqueous hydrochloric acid solution with dicyclohexano-18-crown-6 isomer A (Isub(a)) and isomer B (Isub(b)) in 1,2-dichloroethane is presented. The extracted species were found to be 1:2 (metal/crown) for Isub(a) and 2:3 for Isub(b) from slope analysis and direct determination of extracted complexes. The extraction equilibrium constants (Ksub(ex)) were determined at 25 deg C and are equal to 29.5 and 0.208, respectively. It is concluded that Isub(a) has a stronger coordination ability for uranium than Isub(b). The different orientation of lone pairs of the oxygen atoms in both isomers has to be taken into account for interpereting the above results. (author)

  19. Standardization of solvent extraction procedure for determination of uranium in seawater

    International Nuclear Information System (INIS)

    Sukanta Maity; Sahu, S.K.; Pandit, G.G.

    2015-01-01

    Solvent extraction procedure using ammonium pyrolidine dithiocarbamate complexing agent in methyl isobutyl ketone organic phase and acid exchange back-extraction is described for the simultaneous quantitative pre-concentration of uranium in seawater followed by its determination by differential pulse adsorptive stripping voltammetry. Solvent extraction time is optimized for extraction of uranium from seawater. Solvent extraction efficiency for uranium in seawater at different pH was carried out. The method gives a recovery of 98 ± 2 % for 400 mL sample at pH 3.0 ± 0.02, facilitating the rapid and interference free analysis of seawater samples. (author)

  20. Estimation of rare earth elements in uranium matrix after solvent extraction of uranium as uranium-antipyrine-anion complex using chloroform as solvent

    International Nuclear Information System (INIS)

    Bose, Roopa; Murthy, D.S.R.; Malhotra, R.K.

    1999-01-01

    The neutron economy in a nuclear reactor dictates the occurrence of neutron absorbers at very low levels. Hence the determination of lanthanides especially Sm, Eu, Gd and Dy is one of the most difficult and complicated analytical tasks particularly in high uranium matrix. Solvent extraction is a potent and versatile technique for the separation of lanthanides. The systems generally used for lanthanide extraction are TBP-nitrate, TBP-chloride, TBP-thiocyanate TOPO, DEHPA-nitrate etc. However, these methods of extraction of lanthanides fail to give a clear cut separation for their determination from uranium matrix. Hence analytical procedures have been standardised for extraction of uranium matrix into the organic phase leaving lanthanides unextracted in the aqueous phase. In this direction Cyanex-923 a mixture of 4 trialkyl phosphine oxides, TBP- TOPO and trioctylamine in xylene have been used for extraction of uranium and consequent determination of lanthanides by ICP-AES in the aqueous phase. In this paper the authors have investigated uranium -antipyrine -anion, a different combination other than the well known phosphine oxides and tertiary amines for extraction of uranium

  1. Comparison between the tricaprylylamine and trilaurilamine extrability in uranium and mobibdenum extraction of low concentration liquors

    International Nuclear Information System (INIS)

    Duarte Neto, J.; Coelho, S.V.

    1980-01-01

    The extrability of trilaurilamine and tricaprylilamine in uranium and molibdenum extraction of sulfuric lixivium were studied and compared. The characteristics of solvent extraction, phase separation, emulsion formation and impurity interference were also determined. (C.G.C.) [pt

  2. Solvent. I. Extraction systems applied to uranium analysis. I. Extraction studies with Tributyl phosphate-Methyl-isobutyl-ketone

    International Nuclear Information System (INIS)

    Vera Palomino, J.; Palomares Delgado, F.; Petrement Eguiluz, J. C.

    1964-01-01

    A factorial study of the selective extraction of uranium with a mixture of TBP-MIC was carried out using 0,8 N nitric acid and different salting agents. We use the most suitable salting agent to develop new factorial experiments in order to get an equation involving the percent of extracted uranium, E, the concentration of the extraction agent in the organic phase, c, and the concentration of the slating agent in the aqueous phase, n. (Author) 3 refs

  3. Extraction of Uranium Using Nitrogen Dioxide and Carbon Dioxide for Spent Fuel Reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Kayo Sawada; Daisuke Hirabayashi; Youichi Enokida [EcoTopia Science Institute, Nagoya University, Nagoya, 464-8603 (Japan)

    2008-07-01

    For the reprocessing of spent nuclear fuels, a new method to extract actinides from spent fuel using highly compressed gases, nitrogen dioxide and carbon dioxide was proposed. Uranium extraction from broken pieces, whose average grain size was 5 mm, of uranium dioxide pellet with nitrogen dioxide and carbon dioxide was demonstrated in the present study. (authors)

  4. Application of liquid-liquid extraction in uranium hydrometallurgy (Paper No. : V-1)

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, T K.S.; Koppiker, K S

    1979-01-01

    Uranium recovery from the ores is carried out exclusively by hydrometallurgical techniques. The initial solubilisation of uranium is achieved by either sodium carbonate or sulphuric acid leaching, the latter being more common. Further purification and upgrading of uranium from the sulphate liquors is carried out by an ion-exchange process. Solid resin type anion exchangers or liquid ion-exchangers are employed. The processing of uranium liquors is, perhaps, the first major application of liquid-liquid extraction in metal recovery. Organophosphoric acids were initially used but later the long-chain aliphatic amines have superseded them. The amine extraction system has been widely studied and several variations are now known. Chloride, nitrate, carbonate or sulphate or acid stripping can be used for getting back the uranium into the aqueous phase. Combination of ion exchange (resin type) and solvent extraction processes called Eluex processes are developed for special applications. Studies have also been made of solvent extraction of uranium from leach pulps instead of clear liquors. Tributylphosphate has found wide application in the refining of uranium concentrates to meet the stringent needs of nuclear purity. liquid-liquid extraction is, perhaps, the only successful technique for the recovery of uranium, as by-product, from wet-process phosphoric acid. This has opened up a new source of uranium.

  5. Uranium extraction from ores with salicylic acid; I - uranium extraction from input phosphate ore of Abu Zaabal phosphate plant, Egypt

    International Nuclear Information System (INIS)

    Hussein, E.M.

    1997-01-01

    Salicylic acid has been tested (for environmental importance) to extract U from input phosphate ore of Abu-Zaabal phosphate plant, Egypt prior to its processing for production of phosphatic fertilizers. Uranyl ion forms with this acid three stable complexes; namely [UO 2 Sal] degree, [U O 2 SaL 2 ] 2- and UO 2 SaL-3] 4- depending on the total uranyl and salicylic acid concentrations and their ratios. Study of relevant extraction factors revealed however that, the extraction process is controlled by the amount of salicylic acid used, alcohol/aqueous ratio, solid/liquid ratio and time of agitation. The obtained results showed that uranium is selectively leached by the application of such a leaching reagent. In order to recover U from the obtained pregnant leach liquor, the latter is adjusted by ammonia to PH 5-6.5, where the crystalline pp t of N H 4 [UO 2 SaL 3 ] 4 H 2 O has formed. This precipitation has been carried out after concentrating the obtained pregnant leach liquor by its recycle for U extraction from new ore batches. The precipitated ammonium uranyl tri salicylate is calcined at 500 degree C for obtaining pure orange yellow trioxide (UO 3 ) powder. On the basis of one ton ore treatment, an economic flowsheet for U recover y from the study ore material has been suggested

  6. Determination of uranium and plutonium in high active solutions by extractive spectrophotometry

    International Nuclear Information System (INIS)

    Subba Rao, R.V.; Damodaran, K.; Santosh Kumar, G.; Ravi, T.N.

    2000-01-01

    Plutonium and uranium was extracted from nitric acid into trioctyl phosphine oxide in xylene. The TOPO layer was analysed by spectrophotometry. Thoron was used as the chromogenic agent for plutonium. Pyridyl azoresorcinol was used as chromogenic agent for uranium. The molar absorption coefficient for uranium and plutonium was found to be 19000 and 19264 liter/mole-cm, respectively. The correlation coefficient for plutonium and uranium was found to be 0.9994. The relative standard deviation for the determination of plutonium and uranium was found to be 0.96% and 1.4%, respectively. (author)

  7. Correction in the efficiency of uranium purification process by solvent extraction

    International Nuclear Information System (INIS)

    Franca Junior, J.M.

    1981-01-01

    An uranium solvent extraction, of high purification, with full advantage of absorbed uranium in the begining of process, is described. Including a pulsed column, called correction column, the efficiency of whole process is increased, dispensing the recycling of uranium losses from leaching column. With the correction column the uranium losses go in continuity, for reextraction column, increasing the efficiency of process. The purified uranium is removed in the reextraction column in aqueous phase. The correction process can be carried out with full efficiency using pulsed columns or chemical mixer-settlers. (M.C.K.) [pt

  8. Processes for extracting radium from uranium mill tailings

    International Nuclear Information System (INIS)

    Nirdosh, I.; Baird, M.H.; Muthuswami, S.V.

    1987-01-01

    This patent describes a process for the extraction of radium from uranium mill tailings solids including the steps of contacting the tailings with a liquid leaching agent, leaching the tailings therewith and subsequently separating the leachate liquid and the leached solids. The improvement described here is wherein the leaching agent comprises: (a) a complexing agent in an amount of from 2 to 10 times the stoichiometric amount needed to complex the metal ions to be removed thereby from the tailings; and (b) a reducing agent reducing the hydrolysable ions of the metal ions to be removed to their lower oxidation states, the reduction agent being present in an amount from 2 to 10 times the stoichiometric amount needed for reducing the hydrolysable metals present in the tailings

  9. Use of a pulsed column with discs and crowns for uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    1982-04-01

    The physico-chemistry of the system phosphoric acid-uranium-dioctylpyrophosphoric acid is studied for the determination of analytical methods and extraction parameters (oxidation state of uranium and iron, phosphorus concentration, extractant concentration). Extraction is then realized on a pilot scale with a liquid-liquid extraction column 4m high and of 50 mm in diameter with a column packing made of discs and crowns. Column efficiency is evaluated by studying uranium transfer as a function of operating conditions. The results obtained are extrapolated to an industrial scale and a comparative economic evaluation is made between a pulsed column and a mixer-settler [fr

  10. Extraction and separation studies of uranium(VI) with tris-(2-ethyl hexyl) phosphate

    International Nuclear Information System (INIS)

    Sundaramurthi, N.M.; Desai, G.S.; Shinde, V.M.

    1990-01-01

    A solvent extraction method is proposed for the extraction and separation of uranium from salicylate media using tris-(2-ethyl hexyl) phosphate dissolved in xylene as an extractant. The optimum conditions were evaluated from a critical study of pH, salicylate concentration, extractant concentration, period of equilibration and diluent. The method permits the separation of uranium from thorium, cerium, titanium, zirconium, hafnium, copper, vanadium and chromium from binary mixtures and is applicable to the analysis of uranium in synthetic samples. The method is precise, accurate, fast and selective. (author) 5 refs.; 2 tabs

  11. Uranium extraction process in a sulfuric medium by means of liquid emulsified membranes

    International Nuclear Information System (INIS)

    Monteillet, A.

    1985-02-01

    Uranium ore processing, after leaching by sulfuric acid, by liquid-liquid extraction is a rather heavy process, not suitable for small deposits. Extraction by emulsions was suggested. In this process the leachate is contacted with an oil in water type emulsion, a liquid organic membrane is formed by the continuous phase. Uranium complexes diffuse through the liquid membrane towards the dispersed aqueous phase of the emulsion (stripping solution). Uranium is recovered by breaking the emulsion. Are successively studied: development of stable emulsions, influence of emulsion composition on uranium transfer kinetics, transfer mechanisms through the membrane and modelling of kinetics data obtained in the experimental study [fr

  12. Supercritical fluid extraction of uranium and thorium from nitric acid medium using organophosphorous compounds

    Energy Technology Data Exchange (ETDEWEB)

    Pitchaiah, K.C.; Sujatha, K.; Rao, C.V.S. Brahmmananda; Subramaniam, S.; Sivaraman, N.; Rao, P.R. Vasudeva [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Chemistry Group

    2015-06-01

    In recent years, Supercritical Fluid Extraction (SFE) technique has been widely used for the extraction of metal ions. In the present study, extraction of uranium from nitric acid medium was investigated using supercritical carbon dioxide (Sc-CO{sub 2}) containing various organophosphorous compounds such as trialkyl phosphates e.g. tri-iso-amyl phosphate (TiAP), tri-sec-butyl phosphate (TsBP) and tri-n-butyl phosphate (TBP), dialkylalkyl phosphonates, e.g. diamylamyl phosphonate (DAAP) and dibutyl butyl phosphonate (DBBP), dialkyl hydrogen phosphonates, e.g. dioctyl hydrogen phosphonate (DOHP), dioctylphosphineoxide (DOPO), trioctyl phosphine oxide (TOPO), n-octylphenyl N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO) and di-2-ethyl-hexyl phosphoric acid (HDEHP). Some of these ligands have been investigated for the first time in the supercritical phase for the extraction of uranium. The extraction efficiency of uranium was studied with TiAP, DAAP and DBBP as a function of nitric acid concentration; the kinetics of the equilibration period (static extraction) and transportation of the metal complex (dynamic extraction) was investigated. The influence of pressure and temperature on the extraction behaviour of uranium with DAAP was studied from 4 N HNO{sub 3}. The extraction efficiency of uranium from 4 N nitric acid medium was found to increase in the order of phosphates < phosphonates < HDEHP < TOPO < CMPO. In the case of phosphates and phosphonates, the maximum extraction of uranium was found to be from 4 N HNO{sub 3} medium. The acidic extractants, HDEHP and DOHP showed relatively higher extraction at lower acidities. The relative extraction of uranium and thorium from their mixture was also examined using Sc-CO{sub 2} containing phosphates, phosphonates and TOPO. The ligand, TsBP provided better fractionation between uranium and thorium compared to trialkyl phosphates, dialkyl alkyl phosphonates and TOPO.

  13. Supercritical fluid extraction of uranium for its purification from various yellow cake matrices

    International Nuclear Information System (INIS)

    Prabhat, Parimal; Rao, Ankita; Tomar, B.S.; Kumar, Pradeep

    2016-01-01

    Uranium is produced from different uranium ores as crude yellow cake of different chemical composition such as sodium diuranate (SDU), ammonium diuranate (ADU), magnesium diuranate (MDU), high temperature uranium peroxide (HTUP) etc. This depends on nature of ores and ore processing methods, availability of required facilities at processing site and other economic as well as environmental factors. These yellow cakes are further processed to produce pure uranium suitable for fuel fabrication facility by conventional solvent extraction process. Supercritical Fluid Extraction (SFE) is being developed as an alternate method for separation in nuclear fields due to its inherent potential to minimize liquid waste generation and process simplification. In present study, SFE of uranium from various yellowcake of different chemical composition has been carried out. Chemical parameter such as effect of TBP amount on SFE of uranium has been carried out and optimized at 2 ml for 200 mg SDU. Instrumental parameter such as temperature and pressure on SFE of uranium has been optimized at 323 K and 15.2 MPa. Extraction efficiency (%) achieved at optimized condition is 91.45 ± 0.2, 97.01 ± 0.75 and 96.72 ± 0.27 for SDU, MDU and HTUP respectively. Purity of uranium before SFE and after has been compared. Further studies is in progress for better understanding of chemical composition of matrix on SFE of uranium and improving purity of uranium separated from this route. (author)

  14. Studies on supercritical fluid extraction behaviour of uranium and thorium nitrates using amides

    International Nuclear Information System (INIS)

    Sujatha, K.; Kumar, R.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2007-01-01

    Supercritical fluid extraction studies of uranyl nitrate and thorium nitrate in mixture were carried out using various amides such as N,N-di(2-ethylhexyl) isobutyramide (D2EHIBA),N,N-dihexyl octanamide (DHOA) and Diisooctyl Butanamide (DiOBA). These studies established a preferential extraction of uranium over thorium. Among the various amides studied, D2EHIBA offered the best rate of preferential extraction of uranium over thorium. (author)

  15. Spectrophotometric Determination of Microamounts of Uranium previous Extraction with TBP-MIC

    International Nuclear Information System (INIS)

    Vera Palomino, J.; Palomares Delgado, F.; Petrement, J.; Fernandez Cellini, R.

    1962-01-01

    Selective extraction of uranium in nitric acid medium with a mixture of Tbp-MIC (1:10) has been achieved. Aluminium nitrate was used as salting agent. Complexing agents were added in order to avoid extraction of impurities. Extraction conditions have been studied so that extraction is almost practically complete in a single run. (Author) 19 refs

  16. Investigation of adsorbers for the extracting of uranium from seawater

    International Nuclear Information System (INIS)

    Witte, E.G.; Astheimer, L.; Schenk, H.J.; Schwochau, K.

    1979-01-01

    Organic ion exchangers have been tested with respect to their efficiency uranium from seawater. A complexing polymer resin which combines fast uptake of uranium with high selectivity is found to be able to accumulate uranium from natural seawater by a factor of 2.6 x 10 5 . (orig.) 891 HK/orig. 892 MKO [de

  17. Application of ion-exchange unit in uranium extraction process in China (to be continued)

    International Nuclear Information System (INIS)

    Gong Chuanwen

    2004-01-01

    The application conditions of five different ion exchange units in uranium milling plant and wastewater treatment plant of uranium mine in China are introduced, including working parameters, existing problems and improvements. The advantages and disadvantages of these units are reviewed briefly. The procedure points to be followed in selecting ion exchange unit are recommended in the engineering design. The primary views are presented upon the application prospects of some ion exchange units in uranium extraction process in China

  18. Mechanism of extraction of uranium (6) by mixtures of phosphororganic extractants

    International Nuclear Information System (INIS)

    Skorovarov, D.I.; Ul'yanov, V.S.; Meshcheryakov, N.M.; Lagutenkov, V.A.; Mikheev, M.V.

    1988-01-01

    Extraction of uranium (6) from sulfuric acid solutions by solution of D2EHPA-TBP(TOPO) mixture in CCl 4 was studied by NMR method (D2HPA-di-2-ethylhexylphosphoric acid, TBP-tributylphosphate, TOPO-trioctylphosphine oxide). It is shown that stability and stoichiometry of formed solvates depends largely on electron-donor ability of organophosphoric base (TBP or TOPO). The presence of neutral base in extractive system leads to blocking of the coordination center of free D2EHPA molecules, growth of the active acid concentration, assisting in additional solvation of uranyl D2EHP molecules and formation of UO 2 (D2EHP) 2 ·nS type complexes. This results in extraction of additional U(6) quantities to organic phase

  19. Application of Solvent-In-Pulp Technique for Uranium Extraction from Mineralization Granite

    International Nuclear Information System (INIS)

    Ali, M.M.; Hussein, A.E.M.; Youseif, W.M.; El Didamony, A.M.

    2017-01-01

    Investigations on uranium extraction from a representative mineralized granite sample (Gattar granite GII) by solvent-in-pulp (SIP) technique were carried out in the present study. For this purpose, the solvent (tri-butyl amine) (TBA) was mixed with the leaching slurry without prior filtration. The influence of various factors affecting the SIP process, such as contact time, solvent concentration, dilution factor, type of surfactant, surfactant/solid ratio were studied. About 91% uranium extraction efficiency was attained by the application of the chosen extraction SIP conditions. Also, about 96% of the loaded uranium could be stripped by using sulfuric acid as an effective stripping agent

  20. MODELING OF THE SOLVENT EXTRACTION EQUILIBRIUM OF URANIUM (VI SULFATE WITH ALAMINE 336

    Directory of Open Access Journals (Sweden)

    É. C. Avelar

    Full Text Available Abstract The present study investigated the solvent extraction of uranium from sulfate acid solutions using Alamine 336 as an extractant dissolved in commercial kerosene Exxsol D-100 and 5% v/v of tridecanol as a modifying agent at room temperature (25±2 ºC and an aqueous/organic volumetric ratio of unity. Experiments were carried out at typical concentration levels like those used at the uranium plant of INB (Indústrias Nucleares do Brasil, Brazil. Data fitting using the slope analysis method revealed that uranium is extracted by Alamine 336 as UO2SO4 and UO2(SO422- species, forming (R3NH+2UO2(SO422- in the organic phase; the extraction of the species UO2(SO434- seems improbable for the operating conditions investigated. The extraction of uranium is significantly reduced when the concentrations of sulfate and chloride ions in the aqueous phase are increased.

  1. Chapter 6. Uranium extraction possibilities from natural uranium-bearing waters of complex salt composition. 6.2. Technology for uranium extraction from brine with a high content of ion-chlorine

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2012-01-01

    Present article is devoted to technology for uranium extraction from brine with a high content of ion-chlorine. The content of basic anions and cations in lake waters of Sasik-Kul deposit was defined. Results of X-ray spectral analysis of salt residual after water evaporation from Sasik-Kul lake was discussed. Investigations revealed that uranium extraction from brines containing ion-chlorine is possible. The developed basic process flow diagram of uranium extraction from Sasik-Kul Lake' brine consists of the following basic stages: evaporation, leaching, catching of formed gases (HCl), sorption, desorption, deposition, drying and tempering.

  2. Chapter 6. Uranium extraction possibilities from natural uranium-bearing waters of complex salt composition. 6.2. Technology for uranium extraction from brine with a high content of ion-chlorine

    International Nuclear Information System (INIS)

    Khakimov, N.; Nazarov, Kh.M.; Mirsaidov, I.U.

    2011-01-01

    Present article is devoted to technology for uranium extraction from brine with a high content of ion-chlorine. The content of basic anions and cations in lake waters of Sasik-Kul deposit was defined. Results of X-ray spectral analysis of salt residual after water evaporation from Sasik-Kul lake was discussed. Investigations revealed that uranium extraction from brines containing ion-chlorine is possible. The developed basic process flow diagram of uranium extraction from Sasik-Kul Lake' brine consists of the following basic stages: evaporation, leaching, catching of formed gases (HCl), sorption, desorption, deposition, drying and tempering.

  3. Solvent-extraction methods applied to the chemical analysis of uranium. III. Study of the extraction with inert solvents

    International Nuclear Information System (INIS)

    Vera Palomino, J.; Palomares Delgado, F.; Petrement Eguiluz, J. C.

    1964-01-01

    The extraction of uranium on the trace level is studied by using tributylphosphate as active agent under conditions aiming the attainment of quantitative extraction by means of a single step process using a number of salting-out agents and keeping inside the general lines as reported in two precedent papers. Two inert solvents were investigated, benzene and cyclohexane, which allowed to derive the corresponding empirical equations describing the extraction process and the results obtained were compared with those previously reported for solvents which, like ethyl acetate and methylisobuthylketone, favour to a more or less extend the extraction of uranium. (Author) 4 refs

  4. Influence of solvent radiolysis on extraction, scrubbing and stripping of uranium and some fission products

    International Nuclear Information System (INIS)

    Gawlowska, W.; Nowak, M.

    1978-01-01

    Radiolytically degraded TBP-n-paraffins solvent was used in the laboratory flow-sheet to study the influence of radiation exposure on decontamination of uranium. The influence of accumulated doses on extraction, scrubbing and stripping of uranium and some fission products has been discussed. (author)

  5. Standardization of solvent extraction procedure for determination of uranium in sea water

    International Nuclear Information System (INIS)

    Maity, Sukanta; Dusane, C.B.; Sahu, S.K.; Pandit, G.G.

    2014-01-01

    Marine ecosystem is becoming polluted by heavy metals and naturally occurring radionuclides due to rapid industrialization and human activities. Many contaminants such as heavy metals and naturally occurring radionuclides though occur at extremely low concentration in sea water, are accumulated by marine organisms and concentrations in their body tissue can be hundreds of times greater than sea water. As human being consume different marine organisms like biota, can lead potential health problem to human being. Uranium is a naturally occurring radioactive element which is important for nuclear technology. However, mineral resources for uranium are limited. Seawater is a major source of uranium. The total estimated quantity of uranium in seawater is around four and a half billion tones. Thus, the oceans have the potential to become the most eco-friendly and long sustainable resource for uranium. A number of countries in the world are in search of techniques to recover uranium from seawater economically. For this purpose and also for the environmental monitoring, the determination of uranium in seawater is very much important. Seawater contains very high concentrations of salts and its uranium content is very low. Accordingly, the separation and preconcentration of uranium is usually involved in the analytical procedures used for the determination of uranium in seawater. In the present study solvent extraction procedure was adopted for the determination of uranium in sea water collected from different locations across Thane Creek area, Mumbai, India

  6. Current extraction and separation of uranium, thorium and rare earths elements from monazite leach solution using organophosphorous extractants

    International Nuclear Information System (INIS)

    Biswas, Sujoy; Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.

    2014-01-01

    A new process based on solvent extraction has been developed for separation of uranium, thorium and rare earths from monazite leach solution using organophosphorous extractants. The Thorium cake coming from monazite source was dissolved in HNO 3 medium in presence of trace amount of HF for feed preparation. The separation of U(VI) was carried out by liquid-liquid extraction using tris-2-ethyl hexyl phosphoric acid (TEHP) in dodecane leaving thorium and rare earths elements in the raffinate. The thorium from raffinate was selectively extracted using 1M tri iso amyl phosphate (TiAP) in dodecane in organic phase leaving all rare earths elements in aqueous solution. The uranium and thorium from organic medium was quantitatively stripped using 0.05 M HNO 3 counter current mode. Results indicate the quantitative separation of uranium, thorium and rare earths from thorium cake (monazite source) using organophosphorous extractant in counter current mode

  7. Extraction equilibrium of uranium (VI) from phosphoric solution with HDEHP and TOPO in cyclohexane

    International Nuclear Information System (INIS)

    You Jianzhang; Zhou Zuming; Qin Qizong

    1988-01-01

    The extraction equilibrium of uranium(VI) from phosphoric acid solution with HDEHP and TOPO in cyclohexane has been investigated to examine the effects of extractant concentration, hydrogen ion concentration and temperature on the extraction of uranium(VI). Experimental results suggest that the composition of synergistic complex species is UO 2 (HA 2 ) 2 ·TOPO and the extraction equilibrium constant β 21 is 10 9.52 at 30 deg C. In addition, the thermodynamic functions of the extraction reaction (ΔG,ΔH,ΔS) and the infra-red spectra of synergistic complexes have also been determined

  8. Study on extraction of uranium from clayey sandstone with floatation-leaching process

    International Nuclear Information System (INIS)

    Meng Guangshou; Zhao Manchang; Wu Peisheng; Song Wenlan; Li Wenxia.

    1985-01-01

    An improved floatation-leaching process is proposed to extract uranium from some clayey sandstone type of ore. By two-step flotation, the ground feed ore can be divided into three urani-ferous sections, i.e., the sulfidic concentrate carrying organic matter, the carbonate concentrate, and the tailings. The sulfidic concentrate is mixed with the tailings and then treated by acid-leaching with the result that 93% uranium extraction can be attained. The excess free acid of the leached slurry is further neutralized with the carbonate concentrate instead of lime commonly used. As a result, approximately 60% uranium extraction can be attained. As a whole, by the flotation-leaching process the acid consumption can be reduced from 200 kg/t down to < 80 kg/t and the uranium extraction can be raised from 85% to 90% as compared with the conventional acid-leaching process

  9. Synthesis of new triphosphonic esters for uranium extraction in phosphoric medium

    International Nuclear Information System (INIS)

    Sturtz, Georges; Pensec, Thierry

    1981-01-01

    Triphosphonic acids obtained by nucleophilic addition of dialkyl phosphites on ethylenic diphosphonates are partially hydrolysed into incompletely esterified triphosphonic acids. Their extracting properties for uranium-IV in phosphonic medium are tested [fr

  10. State of art and tendency of uranium extraction from seawater abroad

    International Nuclear Information System (INIS)

    Zhang Jinrui

    1995-01-01

    The amount of the natural resources in land is becoming smaller and smaller, and the people places hopes on the oceans. This paper describes and discusses the new achievements in the research of uranium extraction from seawater abroad

  11. Review of recent developments in uranium extraction technology

    International Nuclear Information System (INIS)

    Alfredson, P.G.; Crawford, R.E.; Ring, R.J.

    1978-12-01

    Developments in uranium ore processing technology since the AAEC Symposium on Uranium Processing in July 1972 are reviewed. The main developments include the use of autogenous or semi-autogenous grinding, beneficiation techniques such as radiometric sorting, flotation, magnetic and gravity seperation, strong acid and ferric bacterial leaching processes, solution mining and heap leaching operations, horizontal belt filters for solid-liquid separation, continuous ion exchange processes for use with solutions containing up to 8 wt % solids, hydrogen peroxide and ammonia for the precipitation of uranium to improve product yield and purity, and the recovery of by-product uranium from the manufacture of phosphoric acid and copper processing operations

  12. A contribution to the study of mass transfer: uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    Maher, A.

    1985-12-01

    Liquid-liquid extraction of uranium (VI) contained in phosphoric acid is examined. Synergism and thermodynamical equilibria are studied. Influence of drop size, extractant concentration and temperature on reaction kinetics are determined. The experimental study concerns extraction by HDEHP, TOPO and the mixture of both. Reaction mechanisms are interpreted [fr

  13. Extraction of uranium from aqueous solution by phosphonic acid-imbedded polyurethane foam

    International Nuclear Information System (INIS)

    Katragadda, S.; Gesser, H.D.; Chow, A.

    1997-01-01

    Phenylphosphonic acid was imbedded into the matrix of the polyurethane foam during the fabrication process of the polymer. The extraction of uranium by phosphonic acid-imbedded polyurethane foam and blank polyurethane (i.e., foam without phosphonic acid functional groups) was investigated. Phosphonic acid-imbedded foam showed superior extractability of uranium from solutions with pH = 7.0 ± 1.5 over a wide range of temperatures. (author)

  14. Selective extraction and subsequent estimation of uranium in membrane optode

    International Nuclear Information System (INIS)

    Joshi, J.M.; Pandey, A.K.; Manchanda, V.K.

    2006-01-01

    In the present work, the possibility of colour changeable optode for uranium detection in groundwater using 2-(5-bromo-2pyridylazo)-5-diethylaminophenol(Br-PADAP) has been explored. The choice for Br-PADAP was based on the fact that it has been used for developing a uranium specific spectrophotometric determination method in the presence of a large excess of thorium

  15. Non classical sources of uranium and their extraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, V [CEA, 75 - Paris (France)

    1978-11-01

    Non classical uranium sources are reviewed: phosphates, sea water, porphyric copper tailings, minerals allowing in-situ lixiviation, black carbon shales, coals and lignites, granitic rocks. An economical study has shown which sources could be really operative (phosphates seem the most attractive). The situation of uranium supplies does not seem to be actually modified by exploitation of these resources.

  16. Extraction photometric determination of uranium (6) with use of malachite green

    International Nuclear Information System (INIS)

    Stepanenko, Yu.V.; Bagdasarov, K.N.; Shchemeleva, G.G.

    1975-01-01

    A study of the reaction between uranium (6) and malachite green in the presence of sodium benzoate has indicated that, in a weakly acid medium (pH 4.5 to 5.5), the reaction yields a poorly soluble greenish compound which tends to be extracted by a 1-to-1 mixture of benzene and chloroform. The compound comprises uranium, a benzoate and a malachite green in a ratio of 1/3/1. A method has been developed for an extraction-photometric determination of uranium in metallic lead

  17. Extraction photometric determination of uranium (6) with use of malachite green

    Energy Technology Data Exchange (ETDEWEB)

    Stepanenko, Yu V; Bagdasarov, K N; Shchemeleva, G G [Rostovskij-na-Donu Gosudarstvennyj Univ. (USSR)

    1975-12-01

    A study of the reaction between uranium (6) and malachite green in the presence of sodium benzoate has indicated that, in a weakly acid medium (pH 4.5 to 5.5), the reaction yields a poorly soluble greenish compound which tends to be extracted by a 1-to-1 mixture of benzene and chloroform. The compound comprises uranium, a benzoate and a malachite green in a ratio of 1/3/1. A method has been developed for an extraction-photometric determination of uranium in metallic lead.

  18. Selected bibliography for the extraction of uranium from seawater: chemical process and plant design feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Binney, S.E.; Polkinghorne, S.T.; Jante, R.R.; Rodman, M.R.; Chen, A.C.T.; Gordon, L.I.

    1979-02-01

    A selected annotated bibliography of 521 references was prepared as a part of a feasibility study of the extraction of uranium from seawater. For the most part, these references are related to the chemical processes whereby the uranium is removed from the seawater. A companion docment contains a similar bibliography of 471 references related to oceanographic and uranium extraction plant siting considerations, although some of the references are in common. The bibliography was prepared by computer retrieval from Chemical Abstracts, Nuclear Science Abstracts, Energy Data Base, NTIS, and Oceanic Abstracts. References are listed by author, country of author, and selected keywords.

  19. Liquid-liquid extraction of uranium (VI) using Cyanex 272 in kerosene from sodium salicylate medium

    International Nuclear Information System (INIS)

    Kamble, Pravin N.; Mohite, Baburao S.; Suryavanshi, Vishal J.; Salunkhe, Suresh T.

    2015-01-01

    Liquid-liquid extraction of uranium (VI) from sodium salicylate media using Cyanex 272 in kerosene has been carried out. Uranium (VI) was quantitatively extracted from 1x10 -4 M sodium salicylate with 5x10 -4 M Cyanex 272 in kerosene. It was stripped quantitatively from the organic phase with 4M HCl and determined spectrophotometrically with arsenazo(III) at 600 nm. The effects of concentrations of sodium salicylate, metal ions and strippants have been studied. Separation of uranium (VI) from other elements was achieved from binary as well as from multicomponent mixtures. The method is simple, rapid and selective with good reproducibility (approximately ±2%). (author)

  20. Selected bibliography for the extraction of uranium from seawater: chemical process and plant design feasibility study

    International Nuclear Information System (INIS)

    Binney, S.E.; Polkinghorne, S.T.; Jante, R.R.; Rodman, M.R.; Chen, A.C.T.; Gordon, L.I.

    1979-02-01

    A selected annotated bibliography of 521 references was prepared as a part of a feasibility study of the extraction of uranium from seawater. For the most part, these references are related to the chemical processes whereby the uranium is removed from the seawater. A companion docment contains a similar bibliography of 471 references related to oceanographic and uranium extraction plant siting considerations, although some of the references are in common. The bibliography was prepared by computer retrieval from Chemical Abstracts, Nuclear Science Abstracts, Energy Data Base, NTIS, and Oceanic Abstracts. References are listed by author, country of author, and selected keywords

  1. Solid phase extraction of uranium from phosphoric acid. Kinetic and thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Magied, Ahmed Fawzy [Nuclear Materials Authority, Cairo (Egypt); Stockholm Univ. (Sweden). Dept. of Organic Chemistry

    2017-07-01

    There is a high interest to develop suitable solid phase extractants for uranium separation from aqueous solutions in order to reduce cost and enhance the efficiency. This paper describes solid phase extraction of uranium(VI) from aqueous phosphoric acid solution using MCM-41 based D2HEPA-TOPO organophosphorous extractants. The mixture of D2HEPA (di-2-ethyl-hexylphosphoric acid) and TOPO (tri-n-octylphosphine oxide) was impregnated into the pores of MCM-41 and the synthesized sorbent was fully characterized. The influences of different factors such as synergistic mixture ratio, phosphoric acid concentration, mixing time and temperature were investigated. The results showed that 90% of uranium(VI) extraction can be achieved within 5 min, using D2HEPA-TOPO rate at MCM-41 (mass ratio 2:1 w/w) from 1 M phosphoric acid containing 64 ppm of uranium at room temperature. High adsorption capacity of uranium(VI) have been achieved at the mentioned conditions. The rate constant for the chemical adsorption of uranium(VI) was 0.988 g mg{sup -1} min{sup -1} calculated by the pseudo-second order rate equation. The obtained thermodynamics parameters showed that uranium(VI) adsorption from H{sub 3}PO{sub 4} is an exothermic and spontaneous process.

  2. Recovery of uranium from phosphoric acid medium by polymeric composite beads encapsulating organophosphorus extractants

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.K.; Yadav, K.K.; Varshney, L.; Singh, H. [Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2013-07-01

    The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ion concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U{sub 3}O{sub 8}) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na{sub 2}CO{sub 3} solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)

  3. Studies on supercritical fluid extraction of uranium and thorium from liquid and solid matrix

    International Nuclear Information System (INIS)

    Kumar, Pradeep; Pal, Ankita; Saxena, M.K.; Ramakumar, K.L.

    2006-05-01

    Supercritical fluid extraction (SFE) is being widely used in pharmaceutical and food industry. Because of its simplicity, ease of operation and more importantly the reduction in the analytical waste generation, this technique is being viewed as a potential application technique in nuclear industry also. CO 2 is employed as supercritical fluid (SCF) as it is easily recyclable, non-toxic, chemically inert, radiochemically stable and inexpensive. Radioanalytical chemistry section (Radiochemistry and Isotope group) has recently procured a supercritical fluid extraction/chromatography system. The present report describes the work carried out on the system. Detailed study on uranium and thorium extraction from highly acidic medium and tissue paper matrix has been carried out. Direct dissolution and extraction of uranium compounds employing SCF has been carried out. CO 2 was employed as supercritical fluid along with very small amount of Tri n-butyl phosphate (TBP) and Tri n-octyl phosphine oxide (TOPO) as co-solvents. The effect of various operating parameters like CO 2 flow rate, co-solvent percentage, temperature and pressure on extraction was investigated and parameters for maximum extraction were optimized. For comparison, the modes of extraction viz. static and dynamic and modes of complexation viz. in-situ and online were studied. Uranium extraction of ∼98% has been achieved from nitric acid medium employing TBP as co-solvent in 30 minutes extraction time, whereas with TOPO ∼99% uranium extraction could be achieved. Uranium from tissue paper matrix could be extracted upto the extent of 98% with TOPO as co-solvent whereas with TBP extraction of (66.83± 9.80)% was achievable. Direct dissolution of UO 2 , U 3 O 8 , U metal, U-Al alloy solids into SCF CO 2 was carried out employing TBP-HNO 3 complex and SFE of uranium was performed using TBP as co-solvent. UO 2 and U 3 O 8 solids could be dissolved within 20 minutes and extraction of ∼98% was achieved. For U

  4. Prospects for the extraction of uranium from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, F; Cameron, H; Georghiou, L

    1982-10-01

    Current discussions of the long-term prospects for the nuclear power industry centre on disagreements over energy demand forecasts, and on social, political and enviromental issues. The availability of adequate uranium supplies is also necessary for any expansion of generating capacity, and for consideration of possible fast breeder reactor strategies. This paper outlines some of the factors which will determine the viability of one non-conventional source of uranium, and comments on work currently being undertaken at the Universities of Salford and Manchester into exploitation of uranium resources in seawater.

  5. Application and improvement of reciprocating-sieve plate extraction column in natural uranium extraction and purification process

    International Nuclear Information System (INIS)

    Wang Xuejun; Li Linyan; Liu Jing; Liu Xin; Yang Lifeng; Xiao Shaohua; Liu Hao

    2013-01-01

    Reciprocating-sieve plate extraction column is commonly used in the extraction process. Optimization and application were conducted successfully via production practice in some chemical and pharmaceutical plants, and good results are obtained while it is applied in the natural uranium extraction and purification process. The key component of reciprocating-sieve plate extraction column is gear-drive equipment in which drive motor serves as its core. Hence, it is important to select appropriate mode of speed regulation. In this paper, the principle and performance of several mode of speed regulation are compared. Both electromagnetic slip and frequency speed-regulation can be applied in general industrial process, but frequency speed-regulation with low energy cost can be used in wider operating range. The application of frequency speed-regulation mode used in reciprocating-sieve plate extraction column will increase the convenience and stability of natural uranium extraction and purification process. (authors)

  6. Empirical modeling of solvent extraction of uranium from sulphuric acid medium using PC-88A and TOPO as extractants

    International Nuclear Information System (INIS)

    Biswas, S.; Roy, S.B.; Pathak, P.N.; Manchanda, V.K.; Singh, D.K.

    2011-01-01

    Extraction behavior of uranium (VI) from sulphuric acid medium using PC-88A (H 2 A 2 , dimer form) and a mixture of PC-88A + TOPO in n-dodecane has been investigated. The extraction data have been used to develop a mathematical model correlating percentage extraction (%E) with PC-88A and TOPO concentration. It can be used to predict the steady-state concentrations of metal ion under the conditions of the present work. (author)

  7. Uranium Extraction From Artificial Liquid Waste Using Continuous Extraction Liquid membrane Technique

    International Nuclear Information System (INIS)

    Rusdianasari; Buchari

    2002-01-01

    The continuous extraction of uranium from artificial liquid waste by emulsion liquid membrane was carried out using one stage mixer-settler. This emulsion liquid membrane containing di-2-ethylhexylphosphoric acid (D2EHPA) and tri-n-buthyl phosphate (TBP) as carrier were carried out using one stage mixer-settler. The optimum condition gave the ratio of emulsion velocity to the feed velocity 1:4 and steady state reached after five minutes. The optimum condition was obtained at the 90.91 % of uranium recovered from raffinate, using EDTA as the masking agent with concentration 5x10 - 2 M . The total concentration of carrier was 3% with ratio D2EHPA and TBP 3:1. The emulsion liquid membrane has high relative selectivity after steady state with separation factors were α U , N i= 115,43 and α U , Fe 328,55. The result of experiment showed that emulsion liquid membrane containing D2EHPA and TBP as carrier have good performance for continuous system

  8. Extraction of uranium from alkaline medium by aliquot-336 in different diluents

    Energy Technology Data Exchange (ETDEWEB)

    Shehata, F A; Elnadi, Y A; Aly, H F [Hot laboratories center, atomic energy authority 13758, Cairo, (Egypt); Ahmed, A S [Faculty of science, Cairo University, Giza, (Egypt)

    1995-10-01

    A study was made on the extraction of uranium from aqueous solutions containing sodium carbonate and sodium hydroxide in the presence of oxidizing agent (H{sub 2} O{sub 2}) by aliquot-336 dissolved in different diluents. The effect of different factors affecting the extraction equilibrium was experimented. From the results obtained, the extraction equilibrium was elaborated. From the effect of temperature on the extraction, The thermodynamic constants of the system were determined and discussed. 5 figs., 1 tab.

  9. Uranium and plutonium extraction from fluoride melts by lithium-tin alloys

    International Nuclear Information System (INIS)

    Kashcheev, I.N.; Novoselov, G.P.; Zolotarev, A.B.

    1975-01-01

    Extraction of small amounts of uranium (12 wt. % concentration) and plutonium (less than 1.10sup(-10) % concentration) from lithium fluoride melts into the lithium-tin melts is studied. At an increase of temperature from 850 to 1150 deg the rate of process increases 2.5 times. At an increase of melting time the extraction rapidly enhances at the starting moment and than its rate reduces. Plutonium is extracted into the metallic phase for 120 min. (87-96%). It behaves analogously to uranium

  10. Evaluation of various Crown ethers for the supercritical fluid extraction of uranium from nitric acid medium

    International Nuclear Information System (INIS)

    Kumar, Pradeep; Rao, Ankita; Ramakumar, K.L.

    2009-01-01

    Various crowns have been evaluated for supercritical fluid extraction of uranium from nitric acid medium employing HPFOA as counter ion. Uranium extraction efficiency was found to be influenced by cavity size of crown ether and nature of substituents. Complexation tendency of UO 2 2+ increases with increasing cavity size of crown ether. Electron withdrawing substituents decreased the extraction efficiency which could be attributed to decrease in the basicity of four oxygen atoms and hence their bonding ability. Whereas electron donating substituents increased the efficiency due to increases in basicity of oxygen atoms and hence in increase in bonding ability. (author)

  11. Solvent extraction of uranium (VI) by Amberlite Lsub(A-1)

    International Nuclear Information System (INIS)

    Kim, S.S.

    1977-01-01

    The effects of uranium, amine and sulfuric acid concentrate, and temperature on the extraction of uranium(VI) from acidic sulphate solutions by Amberlite Lsub(A-1) in benzene was studied. The extraction of sulfuric acid by Amberlite Lsub(A-1) in benzene was also examined. It was found that 92 to 98 percent extraction was obtained for a uranyl sulphate solution of 5g/1 concentrate containing of 0.2M to 0.3M sulfuric acid, a Amberlite Lsub(A-1) of 5 to 10 percent (weight) in benzene, at a temperature of less than 20 0 C. The mechanism of uranium extraction was discussed on the basis of the resluts obtained. (author)

  12. Extraction chromatographic method of uranium(VI) with high molecular mass amine (ALIQUAT - 336)

    International Nuclear Information System (INIS)

    Roy, Uday Sankar; Dutta, Keshab Kumar

    1999-01-01

    A selective method has been developed for reversed phase extraction chromatographic studies of uranium(VI) with Aliquat - 336 (liquid anion exchanger) coated on silica gel as stationary phase. Quantitative extraction of uranium has been achieved in HCl - medium from 1.25(M)-4(M). The effect of different acids with various concentrations stripping agents, flow rate on extraction and elution have been investigated. The exchange capacity of the prepared exchanger has been determined. Uranium(VI) has been separated quantitatively from Th, Ce, Zr, Pb, Ga, Hg, Fe, La, Pr, Nd, Sm and Cr from a binary mixture by controlling the extraction and elution conditions. The separation of U(VI) from ternary and quarternary mixtures of various metal ions has also been achieved. (author)

  13. Extraction of Uranium with Amin as solvent and HCl as internal phase at membrane emulsion

    International Nuclear Information System (INIS)

    Ninik Bintarti, A.; Bambang-Edi-HB; Sudibyo, R.

    1996-01-01

    An extraction process of uranium by Tri-n-Actylamine(TOA) solution with kerosene as thinner and surfactant of Span-80 as emulgator to bend a membrane emulsion. HCI 0.01 N is used as an internal phase uranium in HNO 3 as feed and butanol is used to split the membrane. In the case of membrane, the result was 1 % vol. TOA and 5 % vol. Span-80, emulsification time was 30 minutes and 50 % vol. HCI 0.01 N. The product of an extraction was concentration of HNO 3 is 3 M. The time of extraction 20 minutes and uranium concentration in feed of 600 ppm will give distribution coefficient of membrane extraction was 5.830 and coefficient of stripping was 0.276

  14. Extraction and Separation of Uranium (VI) and Thorium (IV) Using Tri-n-dodecylamine Impregnated Resins

    International Nuclear Information System (INIS)

    Metwally, E.; Saleh, A.Sh.; El-Naggar, H.A.

    2005-01-01

    Extraction of U(VI) and Th(IV) from chloride and nitrate solutions with tri-n- dodecylamine impregnated on Amberlite XAD4, was investigated. The distribution of U(VI) and Th(IV) was studied at different concentrations of acid, salting-out agent, extractant, aqueous metal ion and other parameters. Absorption spectral studies have been investigated for uranium species in both aqueous HCl solution and the resin phase. From these studies, it is suggested that the tetrachloro complex of U(VI) is formed in the extraction of uranium (VI) from hydrochloric acid solutions by TDA impregnated resin. Stripping of the extracted U(VI) and Th(IV) was assayed with HCl and HNO 3 . Finally, the separation of uranium from thorium and fission products in HCl media was achieved

  15. Measurement of the oxidation-extraction of uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    Lawes, B.C.

    1985-01-01

    The present invention relates to processes for the recovery of uranium from wet-process phosphoric acid and more particularly to the oxidation-extraction steps in the DEPA-TOPO process for such recovery. A more efficient use of oxidant is obtained by monitoring the redox potential during the extraction step

  16. Synthesis of new polyphosphonic acids, uranium extracting agents in a phosphoric medium

    International Nuclear Information System (INIS)

    Pensec, T.

    1981-04-01

    Synthesis of organic phosphorus compounds for liquid-liquid extraction of traces of uranium in concentrated phosphoric acid is studied in view of industrial applications. Diphosphonic acids and monoesters and also triphosphonic acids and related compounds are synthetized. Extraction tests show a better efficiency than OPPA [fr

  17. Supercritical fluid extraction of uranium and thorium using modifier free delivery of ligands

    International Nuclear Information System (INIS)

    Sujatha, K.; Kumar, R.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2009-01-01

    The modifier free controlled delivery of octyl (phenyl)-N,N-diisobutylcarbamoylmethy phosphineoxide (CMPO) using supercritical carbon dioxide was established for the extraction of uranyl nitrate as well as uranyl nitrate sorbed on tissue paper matrix and the results were compared with modifier method. The preferential extraction of uranium over thorium was also demonstrated using di (2-ethylhexyl)isobutyramide (D2EHIBA). (author)

  18. The removal of uranium from acidic media using ion exchange and/or extraction chromatography

    International Nuclear Information System (INIS)

    FitzPatrick, J.R.; Schake, B.S.; Murphy, J.; Holmes, K.; West, M.H.

    1996-06-01

    The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-addition, waste stream polishing is associated with this effort in order to achieve more complete removal of uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps

  19. USE OF MEMBRANE EMULSION SPAN 80 AND TOPO IN URANIUM EXTRACTION AND STRIPPING

    Directory of Open Access Journals (Sweden)

    Kris Tri Basuki

    2017-01-01

    Full Text Available ABSTRACT USE OF MEMBRANE EMULSION SPAN 80 AND TOPO IN URANIUM EXTRACTION AND STRIPPING. Membrane emulsion span 80 and TOPO used in uranium extraction and stripping has been done. The extraction was carried outby emulsion membrane H3PO4 in TOPO-Kerosene. The feed or external aqueous phase was uranium in  HNO3. The emulgator span-80 was used to obtain a stable emulsion membrane system. The influence factors were percentage of TOPO-Kerosene, time extraction,  molarity of external aqueous phase and  molarity of internal aqueous. After the emulsion membrane was formed, the extractionand stripping process was performed. The ratio volume feed : volume membrane phase equal to 1 : 1 and volume of 5 % TOPO-Kerosene : Volume 3 M H3PO4 equal 1 : 1 were used. The relative good yield were obtained at concentration of TOPO in Kerosene and 3 M H3PO4 was 5 %, molarity of internal aqueous phase equal to 1 M, molarity of external aqueous phase 3 M H3PO4 and time extraction equalto 10 minutes with the speed of emulsification was 8000 rpm. At this condition the extraction efficiency of uranium obtained was 97.8 %, the stripping efficiency 52.56 %, and the total efficiency was 53.80 %. Keywords: membrane emulsion, extraction, stripping, span 80, kerosene, uranium. ABSTRAK PENGGUNAAN MEMBRAN EMULSI SPAN 80 DAN TOPO UNTUK EKSTRASI DAN STRIPPING URANIUM. Telah dilakukan penelitian membran emulsi span 80 dan TOPO yang digunakan untuk ekstraksi uranium. Extraksi dengan membran emulsi H3PO4 dalam TOPO-Kerosen. Larutan umpan untuk fasa air eksternal adalah uranium dalam asam nitrat. Untuk memperoleh sistem emulsi yang stabil dipakai emulgator Span 80. Parameter yang berpengaruh adalah persen TOPO-Kerosene, molaritas fasa air internal H3PO4, molaritas fasa air eksternal HNO3 dan waktu ekstraksi. Setelah diperoleh membran emulsi, kemudian dilakukan proses ekstraksi dan stripping, dengan rasio volume umpan : volume membran sebesar 1 : 1; volume 5% TOPO-Kerose : volume 3M

  20. Separation and concentration of uranium by extraction chromatography : U(VI) - H3PO4 system

    International Nuclear Information System (INIS)

    Nobre, J.S.M.

    1981-01-01

    The feasibility of using the extraction chromatographic technique as a way to recover uranium from phosphatic rocks evaluated. The behaviour of uranium from raw phsophoric acid solutions in chromatographic systems using the mixture di(2-ethylhexyl) orthophosphoric acid (D2EHPA) - tributyl phosphate (TBP) as the stationary phase was studied. Materials as alumina, activated carbon and the macroporous resins XAD-4 and XAD-7 were used as supports for organic stationary phase. The best results were obtained with poliacrilic polymer XAD-7, due to its excellent chromatographic properties and efficient organic phase retention. Uranium was quantitatively retained by D2EHPA-TBP-XAD-7 columns from synthetic phosphoric acid solutions with typical composition of phosphatic acid liquors. The elution of uranium from this system was also studied, and the best results were obtained with phosphoric acid solutions. This chromatographic column presented a high stability, not changing their properties even after more than twenty cycles, including the conditioning, sorption, wasking and elution steps. Uranium determinations were perfpormed by indirect titration with potassium dichromate and by molecular absorption spectrophotometry with hydrogen peroxide- carbonate. A new and more sensitive method for uranium determination in phosphoric medium, which might be applied to acid liquors of phosphatic ores, was developed. An extraction-photometric method was used, with Arsenazo III (1,8-dihydroxynaphtalene-3,6-disulphonic acid-2,7-bis(azo-2)-phenylarsonic acid) as the reagent for uranium. (Author) [pt

  1. Maintenance of a labour safety and ecological safety in chinks at extraction of uranium

    International Nuclear Information System (INIS)

    Svambaev, Z.A.; Svambaev, E.A.; Sultanbekov, G.A; Tusupbekova, S.T.; Svambaev, A.S.

    2010-01-01

    The authors of scientific work inform results of research on maintenance of a labour safety and ecological safety in chinks at extraction of uranium. Practical actions on increase of safety and a labour safety in chinks at extraction of uranium in opinion of the author is the practical actions directed on perfection of technological processes, development of means of the control and management of technological processes, modernization of the equipment, the organization of safe workplaces of the personnel. It is necessary to give significant attention to actions connected with improvement of physical protection of radioactive dangerous objects. The basic radiating, toxicological danger at the enterprises underground extractions of uranium are natural atoms uranium - the thorium lines, contained in technological solutions, in finished goods, in radioactive waste products, on a surface of the process equipment, vehicles and packings. In manufacture of uranium use highly toxic substances, such as the concentrated sulfuric acid, hydrogen H 2 O 2 , ammonia water with maintenance - not less than 25 %. The technological circuit of reception sour - oxide natural uranium is represented in the following. The solutions acting from uterus sobered after sedimentation from mechanical impurity and after clarification moves in technical unit sonar where it is possible a sulfuric acid and submit through pump down chinks under pressure to uranium horizon where the productive solution of uranium is formed. The productive solution of uranium with the help of deep pumps through pump out chinks acts on unit of reception of a productive solution, then in modular capacity where there is a process clarification, his ambassador moves on sobered to extraction of uranium that is for processing. On a processing complex the productive solution from modular capacity acts on sobered columns in them occurs sobered uranium from a productive solution on ion exchange pitches or so the sorbent, and

  2. Uranium

    International Nuclear Information System (INIS)

    Cuney, M.; Pagel, M.; Leroy, J.

    1992-01-01

    First, this book presents the physico-chemical properties of Uranium and the consequences which can be deduced from the study of numerous geological process. The authors describe natural distribution of Uranium at different scales and on different supports, and main Uranium minerals. A great place in the book is assigned to description and classification of uranium deposits. The book gives also notions on prospection and exploitation of uranium deposits. Historical aspects of Uranium economical development (Uranium resources, production, supply and demand, operating costs) are given in the last chapter. 7 refs., 17 figs

  3. Extraction of uranium from phosphoric-hydrobromic acid mixture by N-lauryl tri alkyl methylamine

    Energy Technology Data Exchange (ETDEWEB)

    Guirguis, L A [Nuclear materials authority, Cairo, (Egypt); Tadros, N A [Hot laboratories center, atomic energy authority, Cairo, (Egypt)

    1995-10-01

    A uranium recovery process from phosphoric acid produced by the dihydrate method was elaborated. Decomposition of phosphate rock containing 0.02% U is carried out with sulphuric acid. Crude phosphoric acid is filtered off, steam concentrated to 45% P{sub 2} O{sub 5} (6.27 M) and then clarified with activated clay and carbon. The clear phosphoric acid is introduced to uranium extraction after the addition of 0.88 M hydrobromic acid by 0.134 M amberlite LA.2 and 5% decanol, as a modifier, in kerosene. While 10% ammonium sulphate solution is used for stripping. Over 90% uranium recovery is obtained. 6 figs., 1 tab.

  4. On the influence of adsorber performance on plant design for the extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1983-01-01

    Based on simple seawater and dissolved uranium balances the influence of specific adsorber parameters on size and design of production plants with fluidized adsorber beds for the extraction of uranium from seawater is discussed. Besides a critical review of two recently published plant designs in the USA and Japan experimentally determined adsorber data for a polyamidoxim (PAO) granulate are presented together with an evaluation of their influence on the key plant parameters. (orig.) [de

  5. Solvent extraction of uranium from lean grade acidic sulfate leach liquor with alamine 336 reagent

    International Nuclear Information System (INIS)

    Ramadevi, G.; Sreenivas, T.; Navale, A.S.; Padmanabhan, N.P.H.

    2012-01-01

    This paper describes the solvent extraction studies carried out on an acidic low assay uranium bearing leach liquor generated during sulfuric acid leaching of a refractory uranium ore using alamine 336-isodecenol-kerosene reagent combine. The leach liquor has a U 3 O 8 content of about 270 mg/L, free acidity 2.4 N H 2 SO 4 and total dissolved solids concentration of 260 g/L. Process parameteric variation studies indicated strong influence of free acidity of the leach liquor, alamine 336 concentration and aqueous to organic phase ratio on the extraction efficiency of uranium. An extraction efficiency of about 95% was achieved when the free acidity of leach liquor was 1 N H 2 SO 4 or lower, using 2% (v/v) alamine 336 at ambient temperature with an aqueous to organic phase ratio of 1:1. The loading capacity under these conditions was 1.2 g/L of U 3 O 8 . About 98% of the uranium values could be stripped from the loaded organic using 1 N NaCl in 0.2 N H 2 SO 4 . The solvent extraction studies aided in developing a suitable process flowsheet for treating refractory uranium ores which need high acidity during leaching and relatively lower acidity for purification by solvent extraction. (author)

  6. A solvent proceed for the extraction of the irradiate uranium and plutonium in the reactor core; Un procede par solvant pour l'extraction du plutonium de l'uranium irradie dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, B; Regnaut, P; Prevot, I [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Description of the conditions of plutonium, fission products and of uranium separation by selective extraction of the nitrates by organic solvent, containing a simultaneous extraction of plutonium and uranium, followed by a plutonium re-extraction after reduction, and an uranium re-extraction. The rates of decontamination being insufficient in this first stage, we also describes the processes of decontamination permitting separately to get the rates wanted for uranium and plutonium. Finally, we describes the beginning of the operation that consists in a nitric dissolution of the active uranium while capturing the products of gaseous fission, as well as the final concentration of the products of fission in a concentrated solution. (authors) [French] Description des conditions de separation du plutonium, des produits de fission et de l'uranium au moyen d'une extraction selective des nitrates par solvant organique, comprenant une extraction simultanee du plutonium et de l'uranium, suivie d'une reextraction du plutonium apres reduction, et d'une reextraction de l'uranium. Les taux de decontamination etant insuffisants dans ce premier stade, on decrit egalement les processus de decontamination permettant separement d'obtenir les taux desires pour l'uranium et le plutonium. Enfin, on decrit aussi le debut de l'operation qui consiste en une dissolution nitrique de l'uranium actif en captant les produits de fission gazeux, ainsi que la concentration finale des produits de fission sous forme de solution concentree. (auteurs)

  7. Extraction of Uranium from Seawater: Design and Testing of a Symbiotic System

    Energy Technology Data Exchange (ETDEWEB)

    Slocum, Alex [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2018-02-22

    The U.S. Department of Energy in October 2014 awarded the Massachusetts Institute of Technology (MIT) a Nuclear Energy University Program grant (DE-NE0008268) to investigate the design and testing of a symbiotic system to harvest uranium from seawater. As defined in the proposal, the goals for the project are: 1. Address the design of machines for seawater uranium mining. 2. Develop design rules for a uranium harvesting system that would be integrated into an offshore wind power tower. 3. Fabricate a 1/50th size scale prototype for bench and pool-testing to verify initial analysis and theory. 4. Design, build, and test a second 1/10th size scale prototype in the ocean for more comprehensive testing and validation. This report describes work done as part of DE-NE0008268 from 10/01/2014 to 11/30/2017 entitled, “Extraction of Uranium from Seawater: Design and Testing of a Symbiotic System.” This effort is part of the Seawater Uranium Recovery Program. This report details the publications and presentations to date on the project, an introduction to the project’s goals and background research into previous work done to achieve these goals thus far. From there, the report describes an algorithm developed during the project used to optimize the adsorption of uranium by changing mechanical parameters such as immersion time and adsorbent reuses is described. Next, a design tool developed as part of the project to determine the global feasibility of symbiotic uranium harvesting systems. Additionally, the report details work done on shell enclosures for uranium adsorption. Moving on, the results from the design, building, and testing of a 1/50th physical scale prototype of a highly feasible symbiotic uranium harvester is described. Then, the report describes the results from flume experiment used to determine the affect of enclosure shells on the uptake of uranium by the adsorbent they enclose. From there the report details the design of a Symbiotic Machine for Ocean uRanium

  8. Extraction of uranium from sea water with the granular composite adsorbent by using the fixed bed

    International Nuclear Information System (INIS)

    Katoh, Shunsaku; Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Kitamura, Takao

    1981-01-01

    To clarify the technical problems existing in the extraction process of uranium from sea water, uranium was extracted from natural sea water, with the granulated C-Ti-OH composite adsorbent. The adsorption of uranium from sea water was carried out by using the fixed bed that had been designed in our laboratory. The uranium recovery from the sea water was 13.9% in the adsorption process of 56 d. The adsorbed uranium was eluted from the adsorbent with 0.5 N NaHCO 3 -0.5N Na 2 CO 3 soln. at 70 0 C. The elution recovery was 97.4% for 35 h. The uranium contained in the eluate was concentrated twenty times as much as in the anion exchange process, and then 100 times in the solvent extraction process with oxine-chloroform and TOA-kerosene. About 0.7 g of yellow cake was prepared from natural sea water, and it was identified to be pure 2UO 2 .NH 3 .3H 2 O by X-ray diffraction method and X-ray fluorometry. (author)

  9. Acid lixiviation of phophorite minerals for uranium extraction

    International Nuclear Information System (INIS)

    Linzama, H.; Rivas, J.

    1988-01-01

    Lixiviation studies of the phosphorite mineral, found in the north of Chile, using sulfuric acid solutions are described. These minerals contain 62.0 ppm of Uranium, 24% of Silice, 18.9% of P 2 O 5 and other metal-oxides. The influence of the acid concentration, the amount of acid used, granulometry, and the lixiviation yield as a function of the H 3 PO 4 and uranium concentrations was evaluated. In addition, the thermodinamic parameters of the lixiviation process were also evaluated. (author) [pt

  10. A study of solvent extraction of uranium and thorium with a crown either carboxylic acid

    International Nuclear Information System (INIS)

    Du Hongshan

    1995-03-01

    The solvent extraction of uranium and thorium with a new type of extractant sym-dibenzo-16-crown-5-oxyacetic acid in chloroform has been studied. The extraction efficiencies for both elements depend strongly on pH. At pH 3.5, UO 2 2+ is not extractable, whereas Th 4+ is extracted with greater than 98% efficiency. The dependence of the distribution ratios of UO 2 2+ and Th 4+ on the concentration of sym-dibenzo-16-crown-5-oxyacetic acid are linear and the slopes are 1 and 2 respectively. The results suggest that uranium and thorium appear to form a 1 : 1 and 1 : 2 extraction complex with ligand. A new method for separating U and Th is established, and U and Th with high purity can be obtained. This method have important application to analytical chemistry and nuclear industry. (8 refs., 3 figs.)

  11. Investigation of uranium (VI) extraction mechanisms from phosphoric and sulfuric media by {sup 31}P-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Fries, B.; Marie, C.; Pacary, V.; Berthon, C.; Miguirditchian, M.; Charbonnel, M.C. [CEA, Centre de Marcoule, Nuclear Energy Divison, RadioChemistry and Processes Department - DRCP, F-30207 Bagnols-sur-Ceze (France); Mokhtari, H. [AREVA Mines, Process and Analysis Department - SEPA, F-87250 Bessines-sur-Gartempe (France)

    2016-07-01

    Phosphate rocks contain uranium (∼1000 ppm on average) and are considered as a secondary source for uranium production. Uranium extraction using DEHCNPB (butyl-1-[N,N-bis(2-ethylhexyl)carbamoyl]nonyl phosphonic acid, a bifunctional cationic extractant) has been studied to better understand mechanism differences depending on the original acidic solution (phosphoric or sulfuric). Solvent extraction batch experiments were carried out and the organic phases were probed using {sup 31}P-NMR. This technique enabled to demonstrate that phosphoric acid is poorly extracted by DEHCNPB ([H{sub 3}PO{sub 4}]{sub org} < 2 mM), using direct quantification in the organic phase by {sup 31}P-NMR spectra integration. Moreover, in the presence of uranium in the initial phosphoric acid solution, uranyl extraction by DEHCNPB competes with H{sub 3}PO{sub 4} extraction. Average stoichiometries of U(VI)-DEHCNPB complexes in organic phases were also determined using slope analysis on uranium distribution data. Uranium seems to be extracted from a phosphoric medium by two extractant molecules, whereas more than three DEHCNPB on average would be necessary to extract uranium from a sulfuric medium. Thus, uranium is extracted according to different mechanisms depending on the nature of the initial solution. (authors)

  12. Liquid-liquid extraction of uranium from nitric acid solution using di-n-butylsulfoxide in petroleum ether as extractant

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M.H.; Shahida, S. [Dept. of Chemistry, Univ. of Azad Jammu and Kashmir, Muzaffarabad (Pakistan); Ali, A. [Nuclear Chemistry Div., Pakistan Inst. of Nuclear Science and Technology, Nilore, Islamabad (Pakistan)

    2008-07-01

    A simple, efficient and economical liquid-liquid extraction method has been developed for quantitative extraction of uranium from 2 M HNO{sub 3} using di-n-butyl sulfoxide in petroleum ether. The dependence of the partition reaction of U(VI) on the concentration of HNO{sub 3}, extractant and temperature was studied. The reaction was found to be inversely dependent upon the temperature and the values for related thermodynamics functions ({delta}H, {delta}S, {delta}G) for extraction equilibrium were determined to be -33.6 kJ/mol, -1.29 kJ/mol/degree and -0.11 kJ/mol/degree, respectively. The effect of Al(NO{sub 3}){sub 3} as salting-out agent and diverse ions on the extraction was examined. The salting-out agent slightly enhanced the extraction. All cations studied have showed negligible effect on the extraction, whereas phosphate and fluoride interfered seriously. Among others, oxalate, citrate and sulphide ions affect the extraction to a lesser extent. Uranium was successfully extracted from a synthetic mixture of Ti{sup +4}, Zr{sup +4}, Hf{sup +4} and Th{sup +4} using EDTA as masking agent. Among strippants, deionized water was found most suitable, and the recovery of uranium was noted to be {>=} 96%. The stoichiometric composition of the extracted species was found to be UO{sub 2}(NO{sub 3}){sub 2} . 2DBSO. The extraction mechanism is discussed on the basis of the results obtained. The extractant has high loading as well as recycling capacity without any degradation. The method was also applied to the Standard Reference Material (NBL-49) and the measured value was found to be in agreement with the reported value within {+-}2% deviation. (orig.)

  13. Extraction of uranium from wet process phosphoric acid in centrifugal and mixer-settler batteries

    International Nuclear Information System (INIS)

    Poczynajlo, A.; Giers, M.

    1986-01-01

    Five stage countercurrent batteries were comparatively applied for the extraction of uranium from wet phosphoric acid (Chemical Works, Police) in semitechnical scale. As an extractant phase the 0.16 M equimolar solution of mono- and dinonylphenyolphosphoric acids in kerosene was used. The optimum hydrodynamic and extraction conditions for the batteries were found. Process efficiencies of the apparatus were also determined. 5 refs., 5 figs., 2 tabs. (author)

  14. Improved operating strategies for uranium extraction: a stochastic simulation

    International Nuclear Information System (INIS)

    Broekman, B.R.

    1986-01-01

    Deterministic and stochastic simulations of a Western Transvaal uranium process are used in this research report to determine more profitable uranium plant operating strategies and to gauge the potential financial benefits of automatic process control. The deterministic simulation model was formulated using empirical and phenomenological process models. The model indicated that profitability increases significantly as the uranium leaching strategy becomes harsher. The stochastic simulation models use process variable distributions corresponding to manually and automatically controlled conditions to investigate the economic gains that may be obtained if a change is made from manual to automatic control of two important process variables. These lognormally distributed variables are the pachuca 1 sulphuric acid concentration and the ferric to ferrous ratio. The stochastic simulations show that automatic process control is justifiable in certain cases. Where the leaching strategy is relatively harsh, such as that in operation during January 1986, it is not possible to justify an automatic control system. Automatic control is, however, justifiable if a relatively mild leaching strategy is adopted. The stochastic and deterministic simulations represent two different approaches to uranium process modelling. This study has indicated the necessity for each approach to be applied in the correct context. It is contended that incorrect conclusions may have been drawn by other investigators in South Africa who failed to consider the two approaches separately

  15. Extraction of molybdenum with TBP-dodecane mixture in nitric medium. Application to uranium refining

    International Nuclear Information System (INIS)

    Donnet, Louis

    1993-01-01

    Uranium ores may contain high quantities of molybdenum which represents an undesirable impurity in the uranium conversion process. Thus it is necessary to check carefully its extraction and its stripping during the purification step. The purpose of this study was to investigate the molybdenum behaviour during this step. We have developed a radiochemical method for the determination of the molybdenum concentration in each phase. This method used gamma radiation of technetium 99m issued from molybdenum 99 disintegration. After a systematic study of all the extraction parameters, we have proposed mechanisms accounting for molybdenum extraction and we have calculated the constants for the different equilibria. In particular, we have furnished new data concerning the extraction of polymerised molybdenum species with tri butyl phosphate. We have also determined the polymerization constants of molybdenum in the aqueous phase. The influence of uranium and phosphate ions on the molybdenum behaviour during the extraction and stripping has been investigated. We have shown that the extraction of molybdenum was not modified by uranium but improved in the presence of phosphate ions. In the general case, we have shown that uranium, phosphate ions and the ageing of the solvent have an unfavourable effect on stripping. We have explained this result by the evolution of the complex in the organic phase to an un-stripped polymeric form. In conclusion, our study has allowed to explain the behaviour of molybdenum during the purification process, and the role of impurities present in the industrial solutions. It would serve as a guide to improve the exploitation for a better molybdenum-uranium separation. (author) [fr

  16. Extraction of uranium and copper from sulphate leach liquors of West Central Sinai uraniferrous siltstone of Egypt

    International Nuclear Information System (INIS)

    Amer, T.E.; Mahdy, M.A.; El-Hazek, N.T.; El Bayoumi, R.M.; Hassanein, S.

    2000-01-01

    Extraction of uranium and copper from sulphate leach liquors of west central Sinai ore samples were performed using solvent extraction technique. Sulphate leach solutions were processed for the extraction of copper using 3% v/v LIX 973N. Copper extractions higher than 98.1% were obtained. Then, uranium was extracted using a tertiary amine. Two amines have been studied 2% v/v tri-n-octyl amine and 1.5% Alamine 336. Parameters studied included solvents concentration, contact time and solution pH. Stripping of uranium and copper were studied using sodium carbonate and sulphuric acid, respectively. Conditions were established for determining the number of stages required for extraction and stripping of copper and uranium through the construction of the corresponding McCabe-Theile diagrams. The results obtained have been utilized to formulate a proposed flowsheet for the production of uranium and copper from west central Sinai ore samples. (author)

  17. The basic characteristics of TRPO-GDX-301 resin extraction chromatography and its application in analysis of uranium ore

    International Nuclear Information System (INIS)

    Jin Wenlong; Yao Mingxia.

    1986-01-01

    The basic characteristic, including capacity of column, loading quality of extraction agent, relationship between flow-rate of solution and height of theorical tower plate, leakage of extraction agent, separation behavior of uranium, of TRPO-extraction chromatography for separation of uranium has been inveistigated. The microamount of uranium on column can be eluted with mixed complex solution at pH 5.8-6.2 and determined by 5-Br-PADAP spectrophotometry. The method is simple and easy to operate. It has reasonable precision and accuracy. It is very suitable for determination of 0.002-0.4% uranium in ore

  18. Study on reprocessing of uranium-thorium fuel with solvent extraction for HTGR

    International Nuclear Information System (INIS)

    Jiao Rongzhou; He Peijun; Liu Bingren; Zhu Yongjun

    1992-08-01

    A single cycle process by solvent extraction with acid feed solution is suggested. The purpose is to reprocess uranium-thorium fuel elements which are of high burn-up and rich of 232 U from HTGR (high temperature gas cooled reactor). The extraction cascade tests have been completed. The recovery of uranium and thorium is greater than 99.6%. By this method, the requirement, under remote control to re-fabricate fuel elements, of decontamination factors for Cs, Sr, Zr-Nb and Ru has been reached

  19. Selective extraction of metals from acidic uranium(VI) solutions using neo-tridecano-hydroxamic acid

    International Nuclear Information System (INIS)

    Bardoncelli, F.; Grossi, G.

    1975-01-01

    According to this invention neo-alkyl-hydroxamic acids are employed as ion-exchanging agents in processes for liquid-liquid extraction with the aim of separating, purifying dissolved metals and of converting a metal salt solution into a solution of a salt of the same metal but with different anion. In particular it is an objective of this invention to provide a method whereby a molecular pure uranium solution is obtained by selective extraction from a uranium solution delivered by irradiated fuel reprocessing plants and containing plutonium, fission products and other unwanted metals, in which method neo-tridecane-hydroxamic acid is employed as ion exchanger. (Official Gazette)

  20. The effect of organic water-miscible solvents on the extraction of uranium by TOA

    International Nuclear Information System (INIS)

    Shi Xiukun; Shen Xinghai; Pen Qixiu; Gao Hongchen

    1989-01-01

    The effect of organic water-miscible solvents, such as methanol, ethanol, acetone, dioxane, glycol, dimethylsulfoxide (DMSO), dimethylformamide (DMF), tetrahydrofurance (THF) in aqueous phase on the extraction of uranyl sulphate by tri-n-octylamine (TOA) has been investigated. All data obtained showed that the addition of alcohols, ketones etc. into aqueous phase brings about an increase of distribution ratio of uranium, whereas the addition of DMSO, DMF etc. brings about a decrease of distribution ratio of uranium. In the present study, the regularity and mechanism of extraction with TOA are further studied and discussed from the measurements of some physical properties, such as dielectric constant, interface tension etc

  1. Liquid-liquid extraction and separation studies of uranium(VI)

    International Nuclear Information System (INIS)

    Langade, A.D.; Shinde, V.M.

    1980-01-01

    Separation of uranium(VI) from iron(III), molybdenum(VI), vanadium(V), bismuth(III), zirconium(IV) and thorium(IV) is achieved by liquid-liquid extraction with 4-methyl-3-pentene-2-one (mesityl oxide; MeO) from sodium salicylate media (0.1M, pH 6.0). The extracted species is UO 2 (HO.C 6 H 4 COO) 2 .2MeO. A procedure for separating 50 μg of uranium from mg amounts of the other metals is described. (author)

  2. Economic evaluation of in situ extraction for copper, gold, and uranium

    International Nuclear Information System (INIS)

    Lewis, F.M.; Chase, C.K.; Bhappu, R.B.

    1976-01-01

    In situ extraction for copper, gold, and uranium, generally involves several common alternative processes and techniques. These include dump leaching, heap leaching, leaching of fractured ore in-place or bore hole mining and unit operations such as cementation, solvent extraction, ion-exchange, or carbon-in-pulp. Since the metallurgical effectiveness and economics of such processes and unit operations are well established, it would be possible to select the optimum alternative for extracting either copper, gold, or uranium from their ores using in situ extraction technology. Efforts made to provide metallurgical evaluation as well as capital and operating costs for the various processes and unit operations are reported. These costs are used in preparing feasibility studies for in situ extraction of these metals

  3. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The article briefly discusses the Australian government policy and the attitude of political party factions towards the mining and exporting of the uranium resources in Australia. Australia has a third of the Western World's low-cost uranium resources

  4. Uranium

    International Nuclear Information System (INIS)

    Poty, B.; Cuney, M.; Bruneton, P.; Virlogeux, D.; Capus, G.

    2010-01-01

    With the worldwide revival of nuclear energy comes the question of uranium reserves. For more than 20 years, nuclear energy has been neglected and uranium prospecting has been practically abandoned. Therefore, present day production covers only 70% of needs and stocks are decreasing. Production is to double by 2030 which represents a huge industrial challenge. The FBR-type reactors technology, which allows to consume the whole uranium content of the fuel, is developing in several countries and will ensure the long-term development of nuclear fission. However, the implementation of these reactors (the generation 4) will be progressive during the second half of the 21. century. For this reason an active search for uranium ores will be necessary during the whole 21. century to ensure the fueling of light water reactors which are huge uranium consumers. This dossier covers all the aspects of natural uranium production: mineralogy, geochemistry, types of deposits, world distribution of deposits with a particular attention given to French deposits, the exploitation of which is abandoned today. Finally, exploitation, ore processing and the economical aspects are presented. Contents: 1 - the uranium element and its minerals: from uranium discovery to its industrial utilization, the main uranium minerals (minerals with tetravalent uranium, minerals with hexavalent uranium); 2 - uranium in the Earth's crust and its geochemical properties: distribution (in sedimentary rocks, in magmatic rocks, in metamorphic rocks, in soils and vegetation), geochemistry (uranium solubility and valence in magmas, uranium speciation in aqueous solution, solubility of the main uranium minerals in aqueous solution, uranium mobilization and precipitation); 3 - geology of the main types of uranium deposits: economical criteria for a deposit, structural diversity of deposits, classification, world distribution of deposits, distribution of deposits with time, superficial deposits, uranium

  5. Feasibility studies on supercritical fluid extraction of uranium from phosphoric acid

    International Nuclear Information System (INIS)

    Dubey, B.P.; Agarwal, A.K.

    2014-01-01

    Supercritical fluid extraction (SFE) is a promising novel technology for extraction of many materials. Work has been carried out worldwide on SFE of uranium from various matrices. However, there are no references indicating the R and D on uranium extraction from phosphoric acid using this technology. Heavy Water Board is involved in technology development for recovery of uranium from secondary source, hence it was considered prudent to investigate the technology of SFE for this purpose. Various experiments were carried out with both WPA (P 2 O 5 content 28%) and MGPA (P 2 O 5 content 54%) using bench scale facility available with one of the private party. Extraction experiments were carried out using several chelating agents including TBP, D2EHPA, D2EHPA+TBP/TOPO, TTA, TTA+TBP etc. Feasibility studies revealed the hydrodynamics of operation indicating liquid expansion by about three times during flow of super critical (SC) CO 2 . No flooding was observed when the extraction column filled 20% of its volume capacity, no carryover of entrained/extracted liquid with SC CO 2 with MGPA, material balance of inputs and outputs established i.e. 100% recovery of MGPA and chelating agent, No operational problems with raw MGPA (untreated). No significant extraction of impurities from phosphoric acid to SC CO 2 , 40℃ temperature and 160 bar pressure found ideal for extraction experiments since no other materials found extracted at these conditions and no apparent change/deterioration in PA and chelating agents. Experiments established feasibility of SCE with CO 2 , proper recovery of PA and chelating agents, no need for pretreatment/gunk removal from PA; however, extraction of uranium was found inadequate even though ORP of feed acid was boosted by H 2 O 2 addition. Investigations revealed that SCE column created reducing environment in phosphoric acid, which was not favourable for uranium extraction, which resulted in difficulty in extraction of Uranium. HWB has now designed

  6. Uranium

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

    The author discusses the contribution made by various energy sources in the production of electricity. Estimates are made of the future nuclear contribution, the future demand for uranium and future sales of Australian uranium. Nuclear power growth in the United States, Japan and Western Europe is discussed. The present status of the six major Australian uranium deposits (Ranger, Jabiluka, Nabarlek, Koongarra, Yeelerrie and Beverley) is given. Australian legislation relevant to the uranium mining industry is also outlined

  7. Uranium chloride extraction of transuranium elements from LWR fuel

    International Nuclear Information System (INIS)

    Miller, W.E.; Ackerman, J.P.; Battles, J.E.; Johnson, T.R.; Pierce, R.D.

    1992-01-01

    A process of separating transuranium actinide values from uranium values present in spent nuclear oxide fuels containing rare earth and noble metal fission products as well as other fission products is disclosed. The oxide fuel is reduced with Ca metal in the presence of Ca chloride and a U-Fe alloy which is liquid at about 800 C to dissolve uranium metal and the noble metal fission product metals and transuranium actinide metals and rare earth fission product metals leaving Ca chloride having CaO and fission products of alkali metals and the alkali earth metals and iodine dissolved therein. The Ca chloride and CaO and the fission products contained therein are separated from the U-Fe alloy and the metal values dissolved therein. The U-Fe alloy having dissolved therein reduced metals from the spent nuclear fuel is contacted with a mixture of one or more alkali metal or alkaline earth metal halides selected from the class consisting of alkali metal or alkaline earth metal and Fe or U halide or a combination thereof to transfer transuranium actinide metals and rare earth metals to the halide salt leaving the uranium and some noble metal fission products in the U-Fe alloy and thereafter separating the halide salt and the transuranium metals dissolved therein from the U-Fe alloy and the metals dissolved therein. 1 figure

  8. Solvent extraction of uranium: Towards good practice in design, operation and management

    International Nuclear Information System (INIS)

    Bartsch, P.; Hall, S.; Ballestrin, S.; Hunt, A.

    2014-01-01

    Uranium solvent extraction, USX has been applied commercially for recovery and concentration for over 60 years. Uranium in acidic liquor, which is prepared following ore leaching, solid/liquid separation and clarification, can be treated through a sequence of operations; extraction-scrubbing-stripping, to obtain purified liquor, and hence precipitation of marketable products. USX has dominated the primary uranium industry as the preferred technological route for recovery of uranium into converter grade yellowcake or Uranium Ore Concentrate. The practices of design and operation of USX facilities has found renewed interest as new mines are developed following decades of industry dormancy. Development of the Olympic Dam and Honeymoon operations in Australia has lead to innovative design and operation of pulsed columns technology in applications of solvent extraction. This article seeks to outline principles of design and operation from the practitioner’s perspective. The discussion also reviews historical developments of USX applications and highlights recent innovations. This review is hoped to provide guidance for technical personnel who wish to learn more about good practices that leads to reliable USX performance. (author)

  9. Uranium

    International Nuclear Information System (INIS)

    Stewart, E.D.J.

    1974-01-01

    A discussion is given of uranium as an energy source in The Australian economy. Figures and predictions are presented on the world supply-demand position and also figures are given on the added value that can be achieved by the processing of uranium. Conclusions are drawn about Australia's future policy with regard to uranium (R.L.)

  10. Uranium

    International Nuclear Information System (INIS)

    Toens, P.D.

    1981-03-01

    The geological setting of uranium resources in the world can be divided in two basic categories of resources and are defined as reasonably assured resources, estimated additional resources and speculative resources. Tables are given to illustrate these definitions. The increasing world production of uranium despite the cutback in the nuclear industry and the uranium requirements of the future concluded these lecture notes

  11. Spectrophotometric determination of uranium by previous extraction chromatography separation in polimetalic mineral, phosphorites and technological licours

    International Nuclear Information System (INIS)

    Moreno Bermudez, J.; Cabrera Quevedo, C.; Alfonso Mendez, L.; Rodriguez Aguilera, M.

    1994-01-01

    The development of an analytical procedure for spectrophotometric determination of uranium in polimetalic mineral, phosphorites and technological licours is described. The method is based on the previous separation of interfering elements by extraction chromatography and on spectrophotometric determination of uranium (IV) with arsenazo III in concentrated hydrochloric acid. Tributyl phosphate impregnate on politetrafluoroethylene is used as stationary phase and 5.5 M nitric acid is used as movie phase. The influence of matrix-component elements was studies. The development procedure was applied to real samples, being the results compared with those obtained by other well established analytical methods like gamma-spectrometry, laser fluorimetric, spectrophotometry previous uranium separation by liquid liquid extraction and anion exchange. The reproducibility is evaluated and the detection limited has been established for each studied matrix. A procedure for correcting the thorium interference has been developed for samples with a Th/ 3U8O higher than 0.2

  12. Thin film-XRF determination of uranium following thin-film solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Jalal, E-mail: jalalhassan@ut.ac.ir [Department of Toxicology, Faculty of Veterinary Medicine, University of Tehran (Iran, Islamic Republic of); Hosseini, Seyed M.; Mozaffari, Shahla [Department of Chemistry, Payame Noor University, Tehran (Iran, Islamic Republic of); Jahanparast, Babak; Karbasi, Mohammad H. [Iranian Mineral Processing Research Center, Ministry of Industry and Mineral, Karaj (Iran, Islamic Republic of)

    2014-07-01

    A sensitive method based on the preconcentration of uranium on modified filter paper (thin film) has been developed to determinate this element in water and soil samples by wavelength dispersive X-ray fluorescence. Uranium (VI) extraction from nitric acid medium by trioctyl phosphine (TOPO) from 100 mL of sample was carried out. The effects of nitric acid concentration, TOPO concentration and sample breakthrough on uranium extraction were investigated in this study. The proposed method provided good linearity from 7 to 1000 μg and the limit of detection (LOD), based on a signal-to noise ratio (S/N) of 3, was 2.5 μg. (author)

  13. Separation and preconcentration of uranium from different matrices by extraction chromatography on U-TEVA resin

    International Nuclear Information System (INIS)

    Becquart, Elena T.; Bianco, Gladis N.; Chiacchio, Hugo A.; Palestrini, Leonardo J.; Servant, Roberto E.

    1999-01-01

    The objectives of this work were the determination of uranium in effluents and spring waters, in high and low U 3 O 8 containing minerals and in Zircaloy. The separations were done by extraction chromatography, using U-TEVA Spec (uranium tetravalent actinide specific, ElChroM, Illinois, USA), a commercial resin consisting of Amberlite XAD-7 (Rohm and Haas), an inert support of a non ionic polymeric adsorbent, soaked by diamylamylphosphonate, a selective extractant. Disposable plastic columns, 7.9 mm internal diameter, 10 cm total length, with a bed 4.5 cm high and 2 ml volume were used. Quantification was done by spectrophotometric determination of uranium with the chromogenic reagent 2-(5-bromo-2-pyridylazo)-5-diethyl aminophenol (Br-PADAP). The following working conditions were optimized: uranium sorption and preconcentration, elution, separation of others cations as Zr (IV), Gd (III), Th (IV) and uranium elution, using different solutions of nitric or hydrochloric acids as convenient. Break through was 30 mg of uranium and capacity at total saturation was between 35 and 40 mg U/ml of bed. Programs were developed for previous leaching of minerals and Zircaloy in a microwave oven. Procedures operations were satisfactory with recoveries higher than 95% and a percent relative standard deviation better than 1% for 100 μg of uranium, on five replicates. Quantification limit was 4 ppb (0.1 μg of U in the 25 ml volumetric flask where color was developed with chromogenic reagent), but if uranium is concentrated 5 times in the column and a 5 ml volume is used for elution, a sample containing 0.4 ppb of uranium can be analysed. Absorbance was measured at λ = 578 nm using 5 cm cells. The extraction system is profitable because it allows to work at room temperature, with gravity flow, high specificity and minimum waste generation. The objectives have been satisfactorily accomplished, so an easy, in small columns, uranium sorbing system is available to be used in the

  14. Pre-concentration of uranium from water samples by dispersive liquid-liquid micro-extraction

    Energy Technology Data Exchange (ETDEWEB)

    Khajeh, Mostafa; Nemch, Tabandeh Karimi [Zabol Univ. (Iran, Islamic Republic of). Dept. of Chemistry

    2014-07-01

    In this study, a simple and rapid dispersive liquid-liquid microextraction (DLLME) was developed for the determination of uranium in water samples prior to high performance liquid chromatography with diode array detection. 1-(2-pyridylazo)-2-naphthol (PAN) was used as complexing agent. The effect of various parameters on the extraction step including type and volume of extraction and dispersive solvents, pH of solution, concentration of PAN, extraction time, sample volume and ionic strength were studied and optimized. Under the optimum conditions, the limit of detection (LOD) and preconcentration factor were 0.3 μg L{sup -1} and 194, respectively. Furthermore, the relative standard deviation of the ten replicate was <2.6%. The developed procedure was then applied to the extraction and determination of uranium in the water samples.

  15. Pre-concentration of uranium from water samples by dispersive liquid-liquid micro-extraction

    International Nuclear Information System (INIS)

    Khajeh, Mostafa; Nemch, Tabandeh Karimi

    2014-01-01

    In this study, a simple and rapid dispersive liquid-liquid microextraction (DLLME) was developed for the determination of uranium in water samples prior to high performance liquid chromatography with diode array detection. 1-(2-pyridylazo)-2-naphthol (PAN) was used as complexing agent. The effect of various parameters on the extraction step including type and volume of extraction and dispersive solvents, pH of solution, concentration of PAN, extraction time, sample volume and ionic strength were studied and optimized. Under the optimum conditions, the limit of detection (LOD) and preconcentration factor were 0.3 μg L -1 and 194, respectively. Furthermore, the relative standard deviation of the ten replicate was <2.6%. The developed procedure was then applied to the extraction and determination of uranium in the water samples.

  16. Separation of uranium, molibdenum and vanadium in sulphuric solutions by extraction with alamine 336

    International Nuclear Information System (INIS)

    Floh, B.

    1976-01-01

    Alamine 336 - varsol - sulphuric acid-water system used for uranium, molibdenum and vanadium extraction, from sulphuric leaching and an appropriate plan for fractioning those elements are investigated. The behavior of cited elements in pure solutions followed by interaction that occurs in both bynary and tertiary systems are studied. Distribution coefficient is regarded for measuring such effects [pt

  17. Inorganic-Organic hybrid materials for uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    El-Mourabit, Sabah

    2013-01-01

    Phosphate rocks are industrially processed in large quantities to produce phosphoric acid and fertilisers. These rocks contain significant concentration of uranium (50 to 300 ppm) which could be interesting for nuclear industry. This work deals with the valorisation of uranium as a by-product from fertiliser industry. The aim of this study is to develop a hybrid material, constituted of an inorganic solid support grafted with an extractant (complexing molecule), which can extract selectively uranium from phosphoric acid medium. The first step of our approach was to identify an inorganic support which is stable under these particular conditions (strong acidity and complexing medium). The chemical and mechanical stability of different meso-porous materials, such as silica, glass and carbon was studied. In a second phase, we focused on the identification and the optimisation of complexing molecules, specific of uranium in phosphoric acid. These ligands were then grafted on the most stable solids. Finally, the efficiency of these hybrid systems was evaluated through different tests of extraction, selectivity and de-extraction. (author) [fr

  18. Continuos extraction of uranium and molibdenum by lixiviation with sulfuric acid

    International Nuclear Information System (INIS)

    Cripiani, M.

    1980-01-01

    A methodology for collecting data of uranium and molibdenum extraction by lixiviation with sulfuric acid is showed. Discontinuous tests of lixiviation, time influence, temperature, granulation, acid/ore relation, oxidant/ore relation and solid percentage are studied. (C.G.C.) [pt

  19. Economic aspects of the uranium extraction connected to phosphates found in Brazil

    International Nuclear Information System (INIS)

    Saad, S.

    1974-01-01

    There isn't presently a good perspective for the extraction of uranium connected to phosphates found in Brazilian Northeast. The modernization of equipment required for a better productivity and governmental measures to assure a broader market, may be able to modify such a situation [pt

  20. Extraction of plutonium and uranium from oxalate bearing solutions using phosphonic acid

    International Nuclear Information System (INIS)

    Godbole, A.G.; Mapara, P.M.; Swarup, Rajendra

    1995-01-01

    A feasibility study on the solvent extraction of plutonium and uranium from solutions containing oxalic and nitric acids using a phosphonic acid extractant (PC88A) was made to explore the possibility of recovering Pu from these solutions. Batch experiments on the extraction of Pu(IV) and U(VI) under different parameters were carried out using PC88A in dodecane. The results indicated that Pu could be extracted quantitatively by PC88A from these solutions. A good separation of Pu from U could be achieved at higher temperatures. (author). 6 refs., 3 tabs

  1. Extraction of uranium (VI) sulphate complexes by Adogen amines

    Energy Technology Data Exchange (ETDEWEB)

    Elyamani, I S; Abd Elmessieh, E N [Nuclear chemistry department, hot laboratories center, atomic energy authority, Cairo, (Egypt)

    1995-10-01

    The distribution of U(VI) between aqueous H{sub 2} So{sub 4} solutions and organic phases of adogen-368 has been described. The dependence of extraction on acidity, diluent type, metal and extractant concentrations was investigated. The possible extraction mechanism is discussed in the light of results obtained. The separation of U(VI) from rare earths is suggested. 5 figs., 1 tab.

  2. Extraction of Uranium (VI) Nitrate Complexes By Adogen 464. Vol. 3

    International Nuclear Information System (INIS)

    El-Yamani, I.S.; Abd El-Messieh, E.N.

    1996-01-01

    Long-chain amines are frequently used for the extraction of actinides and offer several advantages for their use in the reprocessing of high burn-up nuclear fuels. The present investigation was undertaken to obtain some information on the extraction of Uranium (VI)by adogen 464 from nitrate medium. Extraction parameters studied include: acidity, salting agent, metal and extractant concentrations, diluent type, and temperature. Extraction mechanism was proposed on the basis of results obtained. Best results were attained at 6 M H N O 3 and sodium nitrate was found to increase appreciably the extraction. It was infrared that extraction was dominated by solvation, and ion exchange reaction mechanisms at lower (<6 M) and higher acidities, respectively. As far as diluents are concerned, the dielectric constant, solvation power and donor characteristics were used to explain the variation in the extraction efficiency of the diluents. Kerosene, the most economic particularly when used on industrial scale, was recommended as optimal diluent. Extractability decreases markedly with rise of temperature, suggesting that the extraction behaviour is exothermic; the thermodynamic functions were also calculated and discussed. A method for the separation of uranium (VI) from some fission products existing in high liquid waste was outlined. 3 figs., 2 tabs

  3. Solvent extraction separation and spectrographic determination of palladium, rhodium and ruthenium in uranium

    International Nuclear Information System (INIS)

    Capdevilla, C.; Alduan, F. A.

    1980-01-01

    The determination of Pd, Rh and Ru in uranium at low ppm level, using solvent extraction has been studied. BPHA, TNOA, TOPO and TBP have been tried as complexing agents; TBP In hexane and 5 M nitric acid medium provides a virtually quantitative extraction. The layer containing the impurities is collected Into graphite powder, and this powder is analysed spectro graphically using carrier destination method with % CuF 2 as a carrier. (Author) 11 refs

  4. Solvent Extraction of Uranium Towards Good Practice in Design, Operation and Management

    International Nuclear Information System (INIS)

    Ring, Bob; Freeman, Paul

    2014-01-01

    Historical Origins: •Originated from nuclear industry uranium concentrates –Based on TBP extractant from nitric acid solutions; –Extractant screening by Oak Ridge National laboratories; • Pilot investigations with acid leach slurries; • Development through commercial application: – Organic phosphoric acids; Dapex e.g. Shiprock –Secondary amine; e.g. Mexican Hat; – Tertiary amine; Amex, e.g. Grants; • Equipment design evolved with each installation

  5. Extraction and selective stripping of uranium and molybdenum in sulfate solution using amines

    International Nuclear Information System (INIS)

    Sialino, E.; Mignot, C.; Michel, P.; Vial, J.

    1977-01-01

    The uranium solutions issued from leaching of AKOUTA ores and containing lot of molybdenum are purified using solvent extraction. During the first test run precipitation of complexes such as amine phosphomolybdate was observed. It was pointed out that the precipitation could be prevented if the molybdenum is oxidized in the feed prior to solvent extraction. Informations on the basic studies carried out to ensure the reliability of the process are given in the complete paper

  6. Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction

    Energy Technology Data Exchange (ETDEWEB)

    Crean, Daniel E. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield (United Kingdom); Centre for Radiochemistry Research, School of Chemistry, The University of Manchester (United Kingdom); Livens, Francis R.; Sajih, Mustafa [Centre for Radiochemistry Research, School of Chemistry, The University of Manchester (United Kingdom); Stennett, Martin C. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield (United Kingdom); Grolimund, Daniel; Borca, Camelia N. [Swiss Light Source, Paul Scherrer Institute, Villigen (Switzerland); Hyatt, Neil C., E-mail: n.c.hyatt@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield (United Kingdom)

    2013-12-15

    Highlights: • Batch leaching was examined to remediate soils contaminated with munitions depleted uranium. • Site specific maximum extraction was 42–50% total U in single batch with NH{sub 4}HCO{sub 3}. • Analysis of residues revealed partial leaching and secondary carbonate phases. • Sequential batch leaching alternating between NH{sub 4}HCO{sub 3} and citric acid was designed. • Site specific extraction was increased to 68–87% total U in three batch steps. -- Abstract: Contamination of soils with depleted uranium (DU) from munitions firing occurs in conflict zones and at test firing sites. This study reports the development of a chemical extraction methodology for remediation of soils contaminated with particulate DU. Uranium phases in soils from two sites at a UK firing range, MOD Eskmeals, were characterised by electron microscopy and sequential extraction. Uranium rich particles with characteristic spherical morphologies were observed in soils, consistent with other instances of DU munitions contamination. Batch extraction efficiencies for aqueous ammonium bicarbonate (42–50% total DU extracted), citric acid (30–42% total DU) and sulphuric acid (13–19% total DU) were evaluated. Characterisation of residues from bicarbonate-treated soils by synchrotron microfocus X-ray diffraction and X-ray absorption spectroscopy revealed partially leached U(IV)-oxide particles and some secondary uranyl-carbonate phases. Based on these data, a multi-stage extraction scheme was developed utilising leaching in ammonium bicarbonate followed by citric acid to dissolve secondary carbonate species. Site specific U extraction was improved to 68–87% total U by the application of this methodology, potentially providing a route to efficient DU decontamination using low cost, environmentally compatible reagents.

  7. Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction.

    Science.gov (United States)

    Crean, Daniel E; Livens, Francis R; Sajih, Mustafa; Stennett, Martin C; Grolimund, Daniel; Borca, Camelia N; Hyatt, Neil C

    2013-12-15

    Contamination of soils with depleted uranium (DU) from munitions firing occurs in conflict zones and at test firing sites. This study reports the development of a chemical extraction methodology for remediation of soils contaminated with particulate DU. Uranium phases in soils from two sites at a UK firing range, MOD Eskmeals, were characterised by electron microscopy and sequential extraction. Uranium rich particles with characteristic spherical morphologies were observed in soils, consistent with other instances of DU munitions contamination. Batch extraction efficiencies for aqueous ammonium bicarbonate (42-50% total DU extracted), citric acid (30-42% total DU) and sulphuric acid (13-19% total DU) were evaluated. Characterisation of residues from bicarbonate-treated soils by synchrotron microfocus X-ray diffraction and X-ray absorption spectroscopy revealed partially leached U(IV)-oxide particles and some secondary uranyl-carbonate phases. Based on these data, a multi-stage extraction scheme was developed utilising leaching in ammonium bicarbonate followed by citric acid to dissolve secondary carbonate species. Site specific U extraction was improved to 68-87% total U by the application of this methodology, potentially providing a route to efficient DU decontamination using low cost, environmentally compatible reagents. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Solid phase extraction of uranium(VI) onto benzoylthiourea-anchored activated carbon

    International Nuclear Information System (INIS)

    Zhao Yongsheng; Liu Chunxia; Feng Miao; Chen Zhen; Li Shuqiong; Tian Gan; Wang Li; Huang Jingbo; Li Shoujian

    2010-01-01

    A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min -1 from the first order rate equation. Thermodynamic parameters (ΔH 0 = -46.2 kJ/mol; ΔS 0 = -98.0 J/mol K; ΔG 0 = -17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na + , Co 2+ , Sr 2+ , Cs + and La 3+ .

  9. Solid phase extraction of uranium(VI) onto benzoylthiourea-anchored activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yongsheng; Liu Chunxia; Feng Miao; Chen Zhen; Li Shuqiong; Tian Gan; Wang Li; Huang Jingbo [College of Chemistry, Sichuan University, 29 Wangjiang Lu, Chengdu, 610064, Sichuan (China); Li Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, 29 Wangjiang Lu, Chengdu, 610064, Sichuan (China)

    2010-04-15

    A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min{sup -1} from the first order rate equation. Thermodynamic parameters ({Delta}H{sup 0} = -46.2 kJ/mol; {Delta}S{sup 0} = -98.0 J/mol K; {Delta}G{sup 0} = -17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na{sup +}, Co{sup 2+}, Sr{sup 2+}, Cs{sup +} and La{sup 3+}.

  10. Supercritical fluid extraction of uranium and neodymium nitrates

    International Nuclear Information System (INIS)

    Sujatha, K.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2011-01-01

    Supercritical fluid extraction (SFE) of uranyl nitrate and neodymium nitrate salts from a mixture was investigated in the present study using Sc-CO 2 modified with various ligands such as organophosphorous compounds, amides, and diketones. Preferential extraction of uranyl nitrate over neodymium nitrate was demonstrated using Sc-CO 2 modified with amide, di-(2ethylhexyl) isobutyramide (D2EHIBA). (author)

  11. Extractants for uranium recovery from wet phosphoric acid

    International Nuclear Information System (INIS)

    Musikas, C.; Benjelloun, N.; Lours, S.

    1982-01-01

    Synergistic mixtures containing phosphine oxide plus one of the acidic extractants: dialkyldithiophosphoric acid, dialkylthiophosphoric acid and dialkylphosphoric acid have been compared with respect to U(VI) and Fe(III) extraction from wet phosphoric acid. Distribution curves slope analysis showed that U(VI) extraction mechanisms are totally different. It has been found that U(VI) is extracted as: UO 2 (H 2 PO 4 )(DEHDTP)(TOPO) ; UO 2 (H 2 PO 4 )(DBTP)(POX) 2 and UO 2 (DEHP)(HDEHP) 2 TOPO in dodecane solutions containing di 2 ethylhexyldithiophosphoric acid (HDEHDTP) or dibutylthiophosphoric acid (HDBTP) or di-2-ethylhexylphosphoric acid (HDEHP) plus a phosphine oxide (TOPO or dihexylmethoxyoctylphosphine oxide (POX 11)). The synergistic mixtures containing HDEHDTP gave the highest U(VI) distribution coefficients. Back extraction with oxalic solutions can be achieved only with the synergistic mixtures containing the acidic thiophosphoric donors

  12. Extraction and determination of hydrogen in uranium and zirconium; Extraction et dosage de l'hydrogene dans l'uranium et le zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Champeix, L; Coblence, G; Darras, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The method of desorption under vacuum at high temperatures in the solid phase, which gives good results in the case of steels, has been applied to uranium and zirconium. In these two metals hydrogen is found mainly in the form of hydride. It is chiefly a question of determining the most suitable temperature and the heating time necessary to obtain an almost total extraction of hydrogen. Two considerations must be taken into account in the choice of temperature. It should be such that on the one hand the hydride decomposes rapidly and completely at the reduced pressure applied, and on the other hand the diffusion of hydrogen through the metal takes place fairly quickly. The apparatus and the method used are described; systematic tests have led to the adoption of temperatures of 650 deg. C for uranium and 1050 deg. C for zirconium. (author) [French] La methode de desorption sous vide a chaud en phase solide, methode qui donne de bons resultats dans le cas des aciers, a ete appliquee a l'uranium et au zirconium. Dans ces deux metaux, l'hydrogene se trouve surtout a l'etat d'hydrure. Il s'agit essentiellement de determiner la temperature optimum et la duree du chauffage necessaire pour obtenir une extraction d'hydrogene pratiquement complete. Deux considerations interviennent dans le choix de la temperature. Elle doit etre telle que, d'une part la decomposition de l'hydrure se fasse rapidement et completement sous la pression reduite realisee et d'autre part que la diffusion de l'hydrogene a travers le metal soit assez rapide. L'appareil et le mode operatoire utilises sont decrits des essais systematiques ont conduit a adopter une temperature de 650 deg. C pour l'uranium et de 1050 deg. C pour le zirconium. (auteur)

  13. Neptunium separation in trace levels from uranium solutions by extraction chromatography

    International Nuclear Information System (INIS)

    Cotrim, M.B.; Matsuda, H.T.

    1994-01-01

    Neptunium and uranium behavior in extraction chromatograph system, aiming the separation of micro quantities of neptunium from uranyl solutions is described. Tri-n-octylamine (TOA), Tri-n-butylphosphate (TBP) as stationary phase, alumine, Voltalef UF-300 as support material were verified. The impregnation conditions as well as the best stationary phase/support material ratio were established. TBP/alumine, TBP/Voltalef and TOA/alumine system were selected to uranium and neptunium separation studies. (author) . 12 refs., 03 tabs., 03 figs

  14. Semitechnical studies of uranium recovery from wet process phosphoric acid by liquid-liquid-extraction method

    International Nuclear Information System (INIS)

    Poczynajlo, A.; Wlodarski, R.; Giers, M.

    1987-01-01

    A semitechnical installation for uranium recovery from wet process phosphoric acid has been built. The installation is based on technological process comprising 2 extraction cycles, the first with a mixture of mono- and dinonylphenylphosphoric acids (NPPA) and the second with a synergic mixture of di-/2-ethylhexyl/-phosphoric acid (D2EHPA) and trioctylphosphine oxide (TOPO). The installation was set going and the studies on the concentration distributions of uranium and other components of phosphoric acid have been performed for all technological circuits. 23 refs., 15 figs., 3 tabs. (author)

  15. Neptunium separation in trace levels from uranium solutions by extraction chromatography

    International Nuclear Information System (INIS)

    Figols, M.E.B.

    1991-01-01

    Neptunium and uranium behavior in extraction chromatography system, aiming the separation of microquantities of neptunium from uranyl nitrate solutions is described. Tri-n-octylamina (TOA), tri-n-butylphosphate (TBP), thenoyltrifluoroacetone (TTA) as stationary phase, alumina, Voltalef-UF-300, silica as support material were verified. The impregnation conditions as well as the best stationary phase/support material ratio were established. TBP/alumina, TBP/Voltalef and TOA/alumina system were selected to uranium and neptunium separation studies. In the system using TBP as extractant agent uranium and neptunium separation was reached by selective elution after the retention of both elements on the column. U-Np separation by selective retention of Np was possible with TOA system. The capacity of the column was the 66.6 mg U/mL and 191.6mg U/mL for the TBP/alumina and TBP/Voltalef systems, respectively. An application of extraction chromatography system in the final phase of irradiated uranium treatment process is proposed. (author)

  16. A rapid method to estimate uranium using ionic liquid as extracting agent from basic aqueous media

    International Nuclear Information System (INIS)

    Prabhath Ravi, K.; Sathyapriya, R.S.; Rao, D.D.; Ghosh, S.K.

    2016-01-01

    Room temperature ionic liquids, as their name suggests are salts with a low melting point typically less than 100 °C and exist as liquid at room temperature. The common cationic parts of ionic liquids are imidazolium, pyridinium, pyrrolidinium, quaternary ammonium, or phosphonium ions, and common anionic parts are chloride, bromide, boron tetrafluorate, phosphorous hexafluorate, triflimide etc. The physical properties of ionic liquids can be tuned by choosing appropriate cations with differing alkyl chain lengths and anions. Application of ionic liquids in organic synthesis, liquid-liquid extractions, electrochemistry, catalysis, speciation studies, nuclear reprocessing is being studied extensively in recent times. In this paper a rapid method to estimate the uranium content in aqueous media by extraction with room temperature ionic liquid tricaprylammoniumthiosalicylate ((A- 336)(TS)) followed by liquid scintillation analysis is described. Re-extraction of uranium from ionic liquid phase to aqueous phase was also studied

  17. Solvent extraction as a method of promoting uranium enrichment by chemical exchange

    International Nuclear Information System (INIS)

    Fathurrachman.

    1995-01-01

    This thesis examines a chemical exchange process for uranium enrichment using solvent extraction. The system selected is the isotope exchange for uranium species in the form of uranous and uranyl chloride complexes. Solvent extraction has been studied before by French workers for this application but little was published on this. Much of this present work is therefore novel. The equilibrium data for the extraction of U(IV) as U 4+ and U(VI) as UO 2 2+ from hydrochloric media into an organic phase containing tri-n-octylamine (TOA) in benzene is given. Benzene is used to prevent third phase formation. In 4 M HCl U(VI) was found to be very soluble in the organic phase but U(IV) was virtually insoluble. Most of the equilibrium data has been correlated by the Langmuir isotherm. This thesis also outlines the methodology that has to be used to design a plant based on this process. (author)

  18. The extraction of uranium from wet process phosphoric acid using a liquid surfactant membrane system

    International Nuclear Information System (INIS)

    Dickens, N.; Davies, G.A.

    1984-01-01

    A liquid membrane extraction process is examined for the extraction of uranium from wet process phosphoric acid. Uranium is present in the acid in concentrations up to 100 ppm which in principle makes it ideal for treatment with a membrane process. The membrane system studied is based on extraction using DEHPA-TOPO reagents which are contained within the organic phase of a water in oil emulsion. Formulations of the emulsion membrane system have been studied, the limitations of acid temperature, P 2 O 5 concentration and solid dispersed impurities in the acid have been studied in laboratory batch experiments and in a continuous pilot plant unit capable of treating 5l of concentrated acid per minute. Data from the pilot plant work has been used to develop a flowsheet for a commercial unit based on this process. (author)

  19. Liquid-solid extraction of uranium (VI) with TOPO - molten naphthalene and determination by laser fluorimetry in geological samples

    International Nuclear Information System (INIS)

    Kumar, Sanjay; Krishnakumar, M.; Patwardhan, A.A.

    2007-01-01

    A simple, rapid, sensitive, cost-effective and efficient method for separation of uranium using tri-n-octylphosphine oxide (TOPO)-molten naphthalene as solid phase extractant and its determination by laser fluorimetry in geological samples (rock, soil, sediment) was developed. Under optimum conditions, using 50 mg TOPO and 100 mg naphthalene, 50 - 5000 ng of uranium in 10 ml sample solution (3% (v/v) HNO 3 ) could be extracted quantitatively. The extracted uranium was stripped using tetra sodium pyrophosphate (5% (v/v) solution, pH adjusted to 7.0 with H 3 PO 4 ) and determined by laser fluorimetry. The influence of different acid concentrations, the amount of solid phase extractant, sample volumes, different stripping reagents, their volumes and effect of foreign ions on the extraction and determination of uranium (VI) were investigated. Synthetic samples of varying concentration as regards uranium were prepared and analysed. Recoveries ranging from 90% to 105% were obtained. The method was validated by analyzing four certified reference materials namely, BL-5, DH-1a, SY-2, SY-3 and the values obtained for uranium agreed well with the certified values. The method was also applied to the determination of uranium in geological samples (rock, soil and sediment) by laser fluorimetry and the results obtained compared favorably with those obtained from the pellet fluorimetry method. Following the proposed method, determination limit for uranium was found to be 1 μg/g with RSD ± 10%. (author)

  20. Study on methods and techniques of aeroradiometric weak information extraction for sandstone-hosted uranium deposits based on GIS

    International Nuclear Information System (INIS)

    Han Shaoyang; Ke Dan; Hou Huiqun

    2005-01-01

    The weak information extraction is one of the important research contents in the current sandstone-type uranium prospecting in China. This paper introduces the connotation of aeroradiometric weak information extraction, and discusses the formation theories of aeroradiometric weak information extraction, and discusses the formation theories of aeroradiometric weak information and establishes some effective mathematic models for weak information extraction. Models for weak information extraction are realized based on GIS software platform. Application tests of weak information extraction are realized based on GIS software platform. Application tests of weak information extraction are completed in known uranium mineralized areas. Research results prove that the prospective areas of sandstone-type uranium deposits can be rapidly delineated by extracting aeroradiometric weak information. (authors)

  1. Development of an on-line analyzer for organic phase uranium concentration in extraction process

    International Nuclear Information System (INIS)

    Dong Yanwu; Song Yufen; Zhu Yaokun; Cong Peiyuan; Cui Songru

    1998-10-01

    The working principle, constitution, performance of an on-line analyzer and the development characteristic of immersion sonde, data processing system and examination standard are reported. The performance of this instrument is reliable. For identical sample, the signal fluctuation in continuous monitoring for four months is less than +-1%. According to required measurement range by choosing appropriate length of sample cell the precision of measurement is better than 1% at uranium concentration 100 g/L. The detection limit is (50 +- 10) mg/L. The uranium concentration in process stream can be automatically displayed and printed out in real time and 4∼20 mA current signal being proportional to the uranium concentration can be presented. So the continuous control and computer management for the extraction process can be achieved

  2. Extraction of uranium from sea water by means of fibrous complex adsorbents

    International Nuclear Information System (INIS)

    Miyamatsu, Tokuhisa; Oguchi, Noboru; Kanchiku, Yoshihiko; Aoyagi, Takanobu

    1982-01-01

    Fibrous complex adsorbents for uranium extraction from sea water were prepared by introducing titanic acid or basic zinc carbonate as effective constituents into fibrous ion exchangers. A fibrous chelate type adsorbent was also tested. Among the adsorbents examined, the following ones demonstrated excellent properties for the recovery of uranium from sea water. a) A fibrous, weakly acidic cation exchanger was treated with titanyl sulfate in aqueous sulfuric acid solution, which was followed by neutralization to afford a fibrous adsorbent containing titanic acid (QC-1f(Ti)). The adsorption capacity for uranium in sea water was estimated by extrapolation to be 50μg-U/g-Ad or 1170 μg-U/g-Ti. b) A fibrous, strongly acidic cation exchanger was treated in a similar way to afford another type of fibrous adsorbent with titanic acid incorporated (QCS-Ti). The adsorption capacity was estimated by extrapolation to be 20-30 μg-U/g-Ad. (author)

  3. Zinc and palladium traces separation from uranium by tri-n-octylamine extraction

    International Nuclear Information System (INIS)

    Moraes, S. de; Cipriani, M.; Abrao, A.

    1974-01-01

    A procedure for the extraction and determination of Zn and Pd as traces from nuclear grade uranium ADU, UO 2 , UO 3 , U 3 O 8 is introduced. The elements are extracted from UO 2 CI 2 -HCI-KI solution with tri-n-octylamine in benzene and determined by atomic absorption spectrophotometry. The adition of potassium iodide to the UO 2 CI 2 -HCI solutions improved the extraction of both elements. Direct burn of the organic phase in the atomic absorption spectrophotometer using hydrogen-air flame provided enhancement of the absorbance for both elements. The relative standard deviations were Zn, 3% and PD, 2.9%

  4. Solvent extraction of uranium(VI) with benzoylacetanilide and its nitro derivatives

    International Nuclear Information System (INIS)

    Mukherjee, Gautam Kumar; Das, Jyotirmoy

    1984-01-01

    The extraction behaviour of uranium(VI) chelates of benzoylacetanilide and four of its mononitro derivatives, viz., benzoyl-o-nitroacetanilide, benzoyl-m-nitroacetanilide, benzoyl-p-nitro-acetanilide and p-nitrobenzoylacetanilide from aqueous solution into carbon tetrachloride has been studied. The extractions have also been carried out in the presence of pyridine, α-picoline, β-picoline and γ-picoline. The extraction constants, and the two phase formation constants of the chelates and adducts have been determined. The effects of the nitro substituent in benzoylacetanilide and formation of syngergistic adducts have been discussed. (author)

  5. Supercritical Fluid Extraction (SFE) of uranium and thorium nitrates using carbon dioxide modified with phosphonates

    International Nuclear Information System (INIS)

    Pitchaiah, K.C.; Sujatha, K.; Brahmananda Rao, C.V.S.; Sivaraman, N.; Vasudeva Rao, P.R.

    2014-01-01

    Supercritical Fluid Extraction (SFE) has emerged as a powerful technique for the extraction of metal ions.The liquid like densities and gas like physical properties of supercritical fluids make them unique to act as special solvents. SFE based procedures were developed and demonstrated in our laboratory for the recovery of actinides from various matrices. In the present study, we have examined for the first time, the use of dialkylalkylphosphonates in supercritical carbon dioxide (Sc-CO 2 ) medium to study the extraction behavior of uranium and thorium nitrates. A series of phosphonates were synthesised by Michaelis-Becker reaction in our laboratory and employed for the SFE

  6. Uranium

    International Nuclear Information System (INIS)

    Whillans, R.T.

    1981-01-01

    Events in the Canadian uranium industry during 1980 are reviewed. Mine and mill expansions and exploration activity are described, as well as changes in governmental policy. Although demand for uranium is weak at the moment, the industry feels optimistic about the future. (LL)

  7. Solvent-extraction and purification of uranium(VI) and molybdenum(VI) by tertiary amines from acid leach solutions

    International Nuclear Information System (INIS)

    La Gamma, Ana M.G.; Becquart, Elena T.; Chocron, Mauricio

    2008-01-01

    Considering international interest in the yellow-cake price, Argentina is seeking to exploit new uranium ore bodies and processing plants. A study of similar plants would suggest that solvent- extraction with Alamine 336 is considered the best method for the purification and concentration of uranium present in leaching solutions. In order to study the purification of these leach liquors, solvent-extraction tests under different conditions were performed with simulated solutions which containing molybdenum and molybdenum-uranium mixtures. Preliminary extraction tests carried out on mill acid-leaching liquors are also presented. (authors)

  8. Further study of extraction equilibrium of uranium(VI) with dicyclohexano-18-crown-6 and its application to separating uranium and thorium

    International Nuclear Information System (INIS)

    Wang Wenji; Sun Qing; Chen Bozhong

    1987-01-01

    The extraction equilibrium of uranium(VI) from aqueous hydrochloric acid solution with dicyclohexano-18-crown-6 isomer A (Ia) and isomer B (Ib) in 1,2-dichloroethane is presented. The extracted species are found to be 1:2 (metal/crown) for Ia and 2:3 for Ib from slope analysis and direct determination of extracted complexes. The extraction equilibrium constants (Kex) were determined at 25 deg C, and were equal to 29.5 for the former and 0.208 for the latter. It is concluded that Ia has stronger coordinate ability for uranium than Ib. The method is effective and selective. The results can be used for the separation of uranium and thorium. (author)

  9. Extractive scintillating polymer sensors for trace-level detection of uranium in contaminated ground water

    International Nuclear Information System (INIS)

    Duval, Christine E.; DeVol, Timothy A.; Husson, Scott M.

    2016-01-01

    This contribution describes the synthesis of robust extractive scintillating resin and its use in a flow-cell detector for the direct detection of uranium in environmental waters. The base poly[(4-methyl styrene)-co-(4-vinylbenzyl chloride)-co-(divinylbenzene)-co-(2-(1-napthyl)-4-vinyl-5-phenyloxazole)] resin contains covalently bound fluorophores. Uranium-binding functionality was added to the resin by an Arbuzov reaction followed by hydrolysis via strong acid or trimethylsilyl bromide (TMSBr)-mediated methanolysis. The resin was characterized by Fourier-transform infrared spectroscopy and spectrofluorometry. Fluorophore degradation was observed in the resin hydrolyzed by strong acid, while the resin hydrolyzed by TMSBr-mediated methanolysis maintained luminosity and showed hydrogen bonding-induced Stokes' shift of ∼100 nm. The flow cell detection efficiency for uranium of the TMSBr-mediated methanolysis resin was evaluated at pH 4, 5 and 6 in DI water containing 500 Bq L"−"1 uranium-233 and demonstrated flow cell detection efficiencies of 23%, 16% and 7%. Experiments with pH 4, synthetic groundwater with 50 Bq L"−"1 uranium-233 exhibited a flow cell detection efficiency of 17%. The groundwater measurements show that the resins can concentrate the uranyl cation from waters with high concentrations of competitor ions at near-neutral pH. Findings from this research will lay the groundwork for development of materials for real-time environmental sensing of alpha- and beta-emitting radionuclides. - Highlights: • Extractive scintillating resins synthesized with covalently bound fluor and ligand. • Methylphosphonic acid-derivitized resins characterized for optical properties. • Online detection of uranium in ground water demonstrated at near-neutral pH.

  10. Extractive scintillating polymer sensors for trace-level detection of uranium in contaminated ground water

    Energy Technology Data Exchange (ETDEWEB)

    Duval, Christine E. [Department of Chemical and Biomolecular Engineering, Clemson University, 127 Earle Hall, Clemson, SC 29634 (United States); DeVol, Timothy A. [Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Court, Anderson, SC 29625 (United States); Husson, Scott M., E-mail: shusson@clemson.edu [Department of Chemical and Biomolecular Engineering, Clemson University, 127 Earle Hall, Clemson, SC 29634 (United States)

    2016-12-01

    This contribution describes the synthesis of robust extractive scintillating resin and its use in a flow-cell detector for the direct detection of uranium in environmental waters. The base poly[(4-methyl styrene)-co-(4-vinylbenzyl chloride)-co-(divinylbenzene)-co-(2-(1-napthyl)-4-vinyl-5-phenyloxazole)] resin contains covalently bound fluorophores. Uranium-binding functionality was added to the resin by an Arbuzov reaction followed by hydrolysis via strong acid or trimethylsilyl bromide (TMSBr)-mediated methanolysis. The resin was characterized by Fourier-transform infrared spectroscopy and spectrofluorometry. Fluorophore degradation was observed in the resin hydrolyzed by strong acid, while the resin hydrolyzed by TMSBr-mediated methanolysis maintained luminosity and showed hydrogen bonding-induced Stokes' shift of ∼100 nm. The flow cell detection efficiency for uranium of the TMSBr-mediated methanolysis resin was evaluated at pH 4, 5 and 6 in DI water containing 500 Bq L{sup −1} uranium-233 and demonstrated flow cell detection efficiencies of 23%, 16% and 7%. Experiments with pH 4, synthetic groundwater with 50 Bq L{sup −1} uranium-233 exhibited a flow cell detection efficiency of 17%. The groundwater measurements show that the resins can concentrate the uranyl cation from waters with high concentrations of competitor ions at near-neutral pH. Findings from this research will lay the groundwork for development of materials for real-time environmental sensing of alpha- and beta-emitting radionuclides. - Highlights: • Extractive scintillating resins synthesized with covalently bound fluor and ligand. • Methylphosphonic acid-derivitized resins characterized for optical properties. • Online detection of uranium in ground water demonstrated at near-neutral pH.

  11. Development of Novel Porous Sorbents for Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wenbin [Univ. of Chicago, IL (United States)

    2017-05-25

    Climate disruption is one of the greatest crises the global community faces in the 21st century. Alarming increases in CO2, NO, SO2 and particulate matter levels will have catastrophic consequences on the environment, food supplies, and human health if no action is taken to lessen their worldwide prevalence. Nuclear energy remains the only mature technology capable of continuous base-load power generation with ultralow carbon dioxide, nitric oxide, and sulfur dioxide emissions. Over the lifetime of the technology, nuclear energy outputs less than 1.5% the carbon dioxide emissions per gigawatt hour relative to coal—about as much as onshore wind power.1 However, in order for nuclear energy to be considered a viable option in the future, a stable supply of uranium must be secured. Current estimates suggest there is less than 100 years’ worth of uranium left in terrestrial ores (6.3 million tons) if current consumption levels remain unchanged.2 It is likely, however, that demand for nuclear fuel will rise as a direct consequence of the ratification of global climate accords. The oceans, containing approximately 4.5 billion tons of uranium (U) at a uniform concentration of ~3 ppb, represent a virtually limitless supply of this resource.3 Development of technologies to recover uranium from seawater would greatly improve the U resource availability, providing a U price ceiling for the current generation and sustaining the nuclear fuel supply for future generations. Several methods have been previously evaluated for uranium sequestration including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons including cost effectiveness, long term stability, and selectivity.4,5 While polymer beads and fibers have been functionalized with amidoxime functional groups to afford U adsorption capacities as high as 1.5 g U/kg,6 further discoveries are needed to make uranium

  12. Development of Novel Porous Sorbents for Extraction of Uranium from Seawater

    International Nuclear Information System (INIS)

    Lin, Wenbin

    2017-01-01

    Climate disruption is one of the greatest crises the global community faces in the 21st century. Alarming increases in CO_2, NO, SO_2 and particulate matter levels will have catastrophic consequences on the environment, food supplies, and human health if no action is taken to lessen their worldwide prevalence. Nuclear energy remains the only mature technology capable of continuous base-load power generation with ultralow carbon dioxide, nitric oxide, and sulfur dioxide emissions. Over the lifetime of the technology, nuclear energy outputs less than 1.5% the carbon dioxide emissions per gigawatt hour relative to coal-about as much as onshore wind power.1 However, in order for nuclear energy to be considered a viable option in the future, a stable supply of uranium must be secured. Current estimates suggest there is less than 100 years' worth of uranium left in terrestrial ores (6.3 million tons) if current consumption levels remain unchanged.2 It is likely, however, that demand for nuclear fuel will rise as a direct consequence of the ratification of global climate accords. The oceans, containing approximately 4.5 billion tons of uranium (U) at a uniform concentration of ~3 ppb, represent a virtually limitless supply of this resource.3 Development of technologies to recover uranium from seawater would greatly improve the U resource availability, providing a U price ceiling for the current generation and sustaining the nuclear fuel supply for future generations. Several methods have been previously evaluated for uranium sequestration including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons including cost effectiveness, long term stability, and selectivity.4,5 While polymer beads and fibers have been functionalized with amidoxime functional groups to afford U adsorption capacities as high as 1.5 g U/kg,6 further discoveries are needed to make uranium extraction from seawater

  13. A Preliminary Study for Development of Amidoxime-functionalized Silica Adsorbents for Uranium(IV) Extraction from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minseok; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    4 billion tons of uranium, which can supply the electricity for tens of thousands of years, is contained in seawater. Therefore, development of techniques for uranium sequestering from the ocean has been regarded as a great challenging for making nuclear energy to be more economical and sustainable. Despite the inexhaustible uranium resource, it is still hard to produce uranium economically from seawater due to its extremely low level of concentration (3.0 μg/L) and stable complex chemical formation, UO{sub 2}(CO3)34-. Various methods for uranium extraction from seawater have been suggested such as precipitation, solvent extraction, ion exchange, adsorption and etc. The most preferred method for extracting uranium is adsorption due to ease of separation from the liquid phase, environment friendliness and cost-effectiveness. Organic or inorganic solids functionalized with amidoxime (AO, -R-C(NH2)=NOH) groups, which has high affinity to uranium species, is the one of candidate material for uranium adsorbents. For long-term nuclear power generation, developing uranium extraction technologies from seawater has been a crucial issue. AO-based adsorbent has been considered as the most effective methods for uranium extraction from seawater, and collaboration with nanotechnology has been tried to enhance the traditional adsorbents, recently. Despite the attempts, most AO-based adsorbents were suffered from complexation of uranyl ions with carbonate ions and under the effect of pH. To achieve more efficient uranium uptake, bi-functionalized mesoporous silica with AO group and acidic groups was chosen as a model for this study.

  14. Recent International R&D Activities in the Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Linfeng

    2010-03-15

    A literature survey has been conducted to collect information on the International R&D activities in the extraction of uranium from seawater for the period from the 1960s till the year of 2010. The reported activities, on both the laboratory scale bench experiments and the large scale marine experiments, were summarized by country/region in this report. Among all countries where such activities have been reported, Japan has carried out the most advanced large scale marine experiments with the amidoxime-based system, and achieved the collection efficiency (1.5 g-U/kg-adsorbent for 30 days soaking in the ocean) that could justify the development of industrial scale marine systems to produce uranium from seawater at the price competitive with those from conventional uranium resources. R&D opportunities are discussed for improving the system performance (selectivity for uranium, loading capacity, chemical stability and mechanical durability in the sorption-elution cycle, and sorption kinetics) and making the collection of uranium from seawater more economically competitive.

  15. Recent International R and D Activities in the Extraction of Uranium from Seawater

    International Nuclear Information System (INIS)

    Rao, Linfeng

    2010-01-01

    A literature survey has been conducted to collect information on the International R and D activities in the extraction of uranium from seawater for the period from the 1960s till the year of 2010. The reported activities, on both the laboratory scale bench experiments and the large scale marine experiments, were summarized by country/region in this report. Among all countries where such activities have been reported, Japan has carried out the most advanced large scale marine experiments with the amidoxime-based system, and achieved the collection efficiency (1.5 g-U/kg-adsorbent for 30 days soaking in the ocean) that could justify the development of industrial scale marine systems to produce uranium from seawater at the price competitive with those from conventional uranium resources. R and D opportunities are discussed for improving the system performance (selectivity for uranium, loading capacity, chemical stability and mechanical durability in the sorption-elution cycle, and sorption kinetics) and making the collection of uranium from seawater more economically competitive.

  16. Systems studies on the extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Driscoll, M.J.; Best, F.R.

    1981-11-01

    This report summarizes the work done at MIT during FY 1981 on the overall system design of a uranium-from-seawater facility. It consists of a sequence of seven major chapters, each of which was originally prepared as a stand-alone internal progress report. These chapters trace the historical progression of the MIT effort, from an early concern with scoping calculations to define the practical boundaries of a design envelope, as constrained by elementary economic and energy balance considerations, through a parallel evaluation of actively-pumped and passive current-driven concepts, and thence to quantification of the features of a second generation system based on a shipboard-mounted, actively-pumped concept designed around the use of thin beds of powdered ion exchange resin supported by cloth fiber cylinders (similar to the baghouse flyash filters used on power station offgas). An assessment of the apparently inherent limitations of even thin settled-bed sorber media then led to selection of an expanded bed (in the form of an ion exchange wool), which would permit an order of magnitude increase in flow loading, as a desirable advance. Thus the final two chapters evaluate ways in which this approach could be implemented, and the resulting performance levels which could be attained. Overall, U 3 O 8 production costs under 200 $/lb appear to be within reach if a high capacity (several thousand ppM U) ion exchange wool can be developed

  17. Extraction of uranium from seawater: chemical process and plant design feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, M.H.; Frame, J.M.; Dudey, N.D.; Kiel, G.R.; Mesec, V.; Woodfield, F.W.; Binney, S.E.; Jante, M.R.; Anderson, R.C.; Clark, G.T.

    1979-02-01

    A major assessment was made of the uranium resources in seawater. Several concepts for moving seawater to recover the uranium were investigated, including pumping the seawater and using natural ocean currents or tides directly. The optimal site chosen was on the southeastern Puerto Rico coast, with the south U.S. Atlantic coast as an alternate. The various processes for extracting uranium from seawater were reviewed, with the adsorption process being the most promising at the present time. Of the possible adsorbents, hydrous titanium oxide was found to have the best properties. A uranium extraction plant was conceptually designed. Of the possible methods for contacting the seawater with the adsorbent, a continuous fluidized bed concept was chosen as most practical for a pumped system. A plant recovering 500 tonnes of U/sub 3/O/sub 8/ per year requires 5900 cubic meters per second of seawater to be pumped through the adsorbent beds for a 70% overall recovery efficiency. Total cost of the plant was estimated to be about $6.2 billion. A computer model for the process was used for parametric sensitivity studies and economic projections. Several design case variations were developed. Other topics addressed were the impact of co-product recovery, environmental considerations, etc.

  18. Extraction of uranium from seawater: chemical process and plant design feasibility study

    International Nuclear Information System (INIS)

    Campbell, M.H.; Frame, J.M.; Dudey, N.D.; Kiel, G.R.; Mesec, V.; Woodfield, F.W.; Binney, S.E.; Jante, M.R.; Anderson, R.C.; Clark, G.T.

    1979-02-01

    A major assessment was made of the uranium resources in seawater. Several concepts for moving seawater to recover the uranium were investigated, including pumping the seawater and using natural ocean currents or tides directly. The optimal site chosen was on the southeastern Puerto Rico coast, with the south U.S. Atlantic coast as an alternate. The various processes for extracting uranium from seawater were reviewed, with the adsorption process being the most promising at the present time. Of the possible adsorbents, hydrous titanium oxide was found to have the best properties. A uranium extraction plant was conceptually designed. Of the possible methods for contacting the seawater with the adsorbent, a continuous fluidized bed concept was chosen as most practical for a pumped system. A plant recovering 500 tonnes of U 3 O 8 per year requires 5900 cubic meters per second of seawater to be pumped through the adsorbent beds for a 70% overall recovery efficiency. Total cost of the plant was estimated to be about $6.2 billion. A computer model for the process was used for parametric sensitivity studies and economic projections. Several design case variations were developed. Other topics addressed were the impact of co-product recovery, environmental considerations, etc

  19. Uranium decontamination in Purex second plutonium cycle: An example of solvent extraction modeling

    International Nuclear Information System (INIS)

    Hsu, T.C.

    1986-01-01

    The existing Purex flowsheet used in the second plutonium cycle at the Savannah River Plant (SRP) does not remove uranium from the plutonium stream. To develop new flowsheets for the Purex second plutonium cycle, computer simulation using SEPHIS was used. SEPHIS is an ORNL-developed solvent extraction simulation code. Box-Wilson experimental design was used to select the minimum set of process conditions simulated. The calculated results were plotted into three-dimensional response surfaces by SAS/Graph (statistical analysis systems). These surfaces provide a broad and complete overview of the responses. Specific ranges of key variables were then investigated. The second series of process simulations identified flowsheets that provide high uranium decontamination while meeting all other key process requirements. The proposed flowsheet consists of modifying the existing 2B bank flowsheet by relocating the feed, increasing the extractant acidity, and adding a scrub stream. The nuclear safety issue was also examined

  20. Solvent extraction and its practical application for the recovery of copper and uranium

    International Nuclear Information System (INIS)

    Reuter, J.

    1975-01-01

    In recent years solvent extraction has been developed to a stage that allows practical application first for the recovery of uranium and later also for winning copper from low-grade acid-soluble ores. By now it has been realized in several plants with great technical and ecomomic success. Solvent extraction includes the following essential operations: leaching, solvent extraction, back extraction of the organically bonded valuable mineral to an acid, aqueous solution and finally separation of the valuable metal from the final acid by precipitation or electrolytic procedures. Upon assessing the cost of the solvent extraction process for the recovery of copper it turns out that from an economic point of view it is significantly superior to the conventional cementation process. (orig.) [de

  1. Determination of uranium and thorium isotopes by solid phase extraction and alpha spectrometry

    International Nuclear Information System (INIS)

    Kuruc, J.; Kovacova, M.; Strisovska, J.; Galanda, D.

    2013-01-01

    The aim of this work was to test the modified method suitable for the separation of isotopes of uranium and thorium samples of rocks, including gold ore and gold concentrate using of extraction chromatography method, after digestion of the sample, concentrating, separate the isotopes of uranium and thorium isotopes to prepare sources for the measurement of alpha spectra. Samples of rocks, gold ore and gold concentrate were digered in microwave decomposition in the environment of hydrogen peroxide and concentrated nitric acid. For the separation of uranium and thorium the vacuum box with cartridges DGA Resin and Resin(R) UTEVA (Triskem International, France) was used. Both sorbents allow separation of uranium from thorium. The results confirmed that the both sorbents give the same results within expanded uncertainty. The mass activity of monitored uranium and thorium radioisotopes was determined by alpha spectrometry method. The yields of separation were determined using uranium-232 as a tracer radionuclide; the activity of 232 U was 0.1438 Bq. Alpha spectra were measured on the Alpha spectrometer EG and G ORTEC 576A with the software MAESTRO, MCA Emulator and Gamma Vision-32 for Windows, USA. Mass activities of radionuclides were converted to mass concentration of isotopes 238 U, 234 U, 232 Th, 230 Th and 228 Th. The highest concentration of 238 U was sampled in granodiorite (Tunnel S-XIV-2, southwards, mining of Cu ore, not working there since 1990), where m( 238 U) = (0.81 ± 0.09) mg kg -1 (DGA Resin) and m( 238 U) = (0.90 ± 0.09) mg kg -1 (UTEVA(R) Resin), as well as m( 232 Th) = (18.8 ± 1.7) mg kg -1 (DGA Resin) and m( 232 Th) = (17.8 ± 1.5) mg kg -1 (UTEVA(R) Resin). In other samples of rocks, gold ore and gold concentrates have specific masses of isotopes of uranium and thorium two-to ten-folds lower. It can be concluded that the rocks, gold ores and concentrates of gold from the 'Rozalia' mine contain lower concentrations of uranium several times against

  2. Extraction of hexavalent uranium, tetravalent plutonium and fission products by N, N'-tetraalkyldiamides

    International Nuclear Information System (INIS)

    Charbonnel, M.C.

    1988-10-01

    This study deals with the extractive properties of N, N'-tetraalkylglutaramides of generic formula R 2 NC(0)(CH 2 ) 3 C(0)NR 2 . These molecules were considered as alternative extractants to tributylphosphate in nuclear fuels reprocessing. They are selective extractants of uranium and plutonium as far as trivalent actinides and lanthanides remain in aqueous nitric solutions. Distribution ratios measurements and F.T. Infra-Red investigations show that HN0 3 extraction takes place via the formation of the following species: 2L.HN0 3 , L.HN0 3 and L.2HN0 3 in the organic phase (L: glutaramide). Distribution ratios of actinide ions followed by UV-visible spectroscopy and Infra-Red investigations agree with formation of the following neutral organometallic complexes in low nitric acidity conditions: L.U0 2 (N0 3 ) 2 and L.Pu(N0 3 ) 4 and the anionic species at higher acidities: L.U0 2 (N0 3 ) 3 H and L.Pu(N0 3 ) 6 H 2 . Interactions occur through neutral complexes and free molecules of diamides which explain the non ideality of the organic phase. Degradation products of these molecules don't seem to alter the extractive properties of these extractants towards uranium and plutonium [fr

  3. Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments

    Science.gov (United States)

    Stoliker, Deborah L.; Campbell, Kate M.; Fox, Patricia M.; Singer, David M.; Kaviani, Nazila; Carey, Minna; Peck, Nicole E.; Barger, John R.; Kent, Douglas B.; Davis, James A.

    2013-01-01

    Extraction techniques utilizing high pH and (bi)carbonate concentrations were evaluated for their efficacy in determining the oxidation state of uranium (U) in reduced sediments collected from Rifle, CO. Differences in dissolved concentrations between oxic and anoxic extractions have been proposed as a means to quantify the U(VI) and U(IV) content of sediments. An additional step was added to anoxic extractions using a strong anion exchange resin to separate dissolved U(IV) and U(VI). X-ray spectroscopy showed that U(IV) in the sediments was present as polymerized precipitates similar to uraninite and/or less ordered U(IV), referred to as non-uraninite U(IV) species associated with biomass (NUSAB). Extractions of sediment containing both uraninite and NUSAB displayed higher dissolved uranium concentrations under oxic than anoxic conditions while extractions of sediment dominated by NUSAB resulted in identical dissolved U concentrations. Dissolved U(IV) was rapidly oxidized under anoxic conditions in all experiments. Uraninite reacted minimally under anoxic conditions but thermodynamic calculations show that its propensity to oxidize is sensitive to solution chemistry and sediment mineralogy. A universal method for quantification of U(IV) and U(VI) in sediments has not yet been developed but the chemical extractions, when combined with solid-phase characterization, have a narrow range of applicability for sediments without U(VI).

  4. Idaho Chemical Processing Plant and Plutonium-Uranium Extraction Plant phaseout/deactivation study

    International Nuclear Information System (INIS)

    Patterson, M.W.; Thompson, R.J.

    1994-01-01

    The decision to cease all US Department of Energy (DOE) reprocessing of nuclear fuels was made on April 28, 1992. This study provides insight into and a comparison of the management, technical, compliance, and safety strategies for deactivating the Idaho Chemical Processing Plant (ICPP) at Westinghouse Idaho Nuclear Company (WINCO) and the Westinghouse Hanford Company (WHC) Plutonium-Uranium Extraction (PUREX) Plant. The purpose of this study is to ensure that lessons-learned and future plans are coordinated between the two facilities

  5. Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R M

    1976-01-01

    Evidence of expanding markets, improved prices and the short supply of uranium became abundantly clear in 1975, providing the much needed impetus for widespread activity in all phases of uranium operations. Exploration activity that had been at low levels in recent years in Canada was evident in most provinces as well as the Northwest Territories. All producers were in the process of expanding their uranium-producing facilities. Canada's Atomic Energy Control Board (AECB) by year-end had authorized the export of over 73,000 tons of U/sub 3/0/sub 8/ all since September 1974, when the federal government announced its new uranium export guidelines. World production, which had been in the order of 25,000 tons of U/sub 3/0/sub 8/ annually, was expected to reach about 28,000 tons in 1975, principally from increased output in the United States.

  6. Evaluation of environmental impacts arising from uranium extraction in Lagoa Real Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Suzicleide L.; Thibes, Ronaldo; Campos, Simara S., E-mail: suzilopes@ig.com.br, E-mail: thibes@uesb.edu.br, E-mail: simaracampos@gmail.com [Universidade Estadual do Sudoeste da Bahia (UESB), Itapetinga, BA (Brazil)

    2013-07-01

    Since the beginnings of the industrial era, there has been an increasing use of fossil fuels, causing a rising of about 30% in the level of carbon dioxide concentrations and, consequently, elevating the global temperature. In the present days, we witness a huge worldwide concern about the generation of energy without emitting polluting gases responsible for the global warming, the so called clean energy. In this way, nuclear energy has reemerged as an important efficient means for generating domestic and industrial energy without producing the toxic greenhouse effect gases. Brazil is one of the current highest economic developing countries, with various internal sectors demanding more and more new technologies and energy consumption. Although traditionally Brazil has lain mainly on hydric resources, nuclear energy appears as real option in the current scenario. In the present work we analyse uranium extraction and processing in the Brazilian Region of Lagoa Real Bahia. In the recent literature, there has appeared some localized works, analyzing environmental impacts arising from the uranium extraction in that region. Based on data collection and analysis of soil, water and teeth, these works represent a first effort in the environmental impacts issue. Building upon published technical results we aim at a global understanding of the problem. Considering such different data sets, we look for global answers relating general aspects of the uranium extraction in the region. We present a comparative study, stressing connections and pointing ou different aspects of the common environmental issue. (author)

  7. Evaluation of environmental impacts arising from uranium extraction in Lagoa Real Bahia

    International Nuclear Information System (INIS)

    Oliveira, Suzicleide L.; Thibes, Ronaldo; Campos, Simara S.

    2013-01-01

    Since the beginnings of the industrial era, there has been an increasing use of fossil fuels, causing a rising of about 30% in the level of carbon dioxide concentrations and, consequently, elevating the global temperature. In the present days, we witness a huge worldwide concern about the generation of energy without emitting polluting gases responsible for the global warming, the so called clean energy. In this way, nuclear energy has reemerged as an important efficient means for generating domestic and industrial energy without producing the toxic greenhouse effect gases. Brazil is one of the current highest economic developing countries, with various internal sectors demanding more and more new technologies and energy consumption. Although traditionally Brazil has lain mainly on hydric resources, nuclear energy appears as real option in the current scenario. In the present work we analyse uranium extraction and processing in the Brazilian Region of Lagoa Real Bahia. In the recent literature, there has appeared some localized works, analyzing environmental impacts arising from the uranium extraction in that region. Based on data collection and analysis of soil, water and teeth, these works represent a first effort in the environmental impacts issue. Building upon published technical results we aim at a global understanding of the problem. Considering such different data sets, we look for global answers relating general aspects of the uranium extraction in the region. We present a comparative study, stressing connections and pointing ou different aspects of the common environmental issue. (author)

  8. Extraction of uranium with TBP in an electrostatic apparatus

    International Nuclear Information System (INIS)

    Kalbasi, M.

    1980-10-01

    An experimental investigation into the utilization of electrostatic energy for solvent extraction of metallic species has been made. Drops were formed at a single nozzle and charged electrically by applying a high d.c. voltage to the nozzle which was arranged to form part of a parallel disc electrode system. After the drops left this electrode zone they travelled through a metallic pipe the purpose of which was to screen the drops from the external electrostatic forces. The liquid system employed in the present work was aqueous uranyl nitrate solution as a dispersed phase and organic tri-n-butyl phosphate (TBP)-diluent as a continuous phase. Uncharged drops were studied in the presence and absence of nitric acid salting agent and in addition both discrete and spray regimes were examined with charged drops. Size, velocity, oscillation motion, charge leakage, actual potential gradient and mass transfer coefficients (reaction rate constants) were studied. A cine camera was used to study the velocity and oscillatory motion of the charged drops moving in the continuous phase in the presence and absence of an electric field. The results of this work suggest that both hydrodynamic and electrostatic forces are responsible for the liquid-liquid extraction rate increase. (author)

  9. Supercritical fluid extraction of uranium from tissue paper matrix using organic extractants

    International Nuclear Information System (INIS)

    Kanekar, A.S.; Bhattacharyya, A.; Pathak, P.N.; Mohapatra, P.K.; Manchanda, V.K.

    2009-01-01

    Direct extraction of dried uranyl nitrate from tissue paper matrix was carried out using supercritical carbon dioxide modified with methanol solutions of extractants such as tri-n-butyl phosphate (TBP) and di-n-hexyl octanamide (DHOA)). The effects of temperature, pressure, extractant and nitric acid concentration on the extraction of uranyl ion were investigated. (author)

  10. Study on automatic control of high uranium concentration solvent extraction with pulse sieve-plate column

    International Nuclear Information System (INIS)

    You Wenzhi; Xing Guangxuan; Long Maoxiong; Zhang Jianmin; Zhou Qin; Chen Fuping; Ye Lingfeng

    1998-01-01

    The author mainly described the working condition of the automatic control system of high uranium concentration solvent extraction with pulse sieve-plate column on a large scale test. The use of the automatic instrument and meter, automatic control circuit, and the best feedback control point of the solvent extraction processing with pulse sieve-plate column are discussed in detail. The writers point out the success of this experiment on automation, also present some questions that should be cared for the automatic control, instruments and meters in production in the future

  11. Selective extractions in uranium migration studies - Findings from a natural analogue study at Palmottu

    International Nuclear Information System (INIS)

    Suksi, J.; Saarinen, L.

    1994-01-01

    The usefulness of chemical extractions in the study on uranium migration is considered in the light of the results compiled at Palmottu. Chemical extractions provide a method for evaluating the mass transfer of U and its retardation in geochemical cycling. The present detailed study provides more specific information on the in situ fixation of U on rock materials. The many observations made at Palmottu show the potential of the method to fill the gap in interpretations between the natural partitioning of U in rock and the distribution of artificial tracers determined by the short-term laboratory experiments. (orig.) (20 refs., 4 figs., 1 tab.)

  12. Solid phase extraction of uranium and thorium on octadecyl bonded silica modified with Cyanex 302 from aqueous solutions

    International Nuclear Information System (INIS)

    Nilchi, A.; Shariati Dehaghan, T.; Rasouli Garmarodi, S.

    2013-01-01

    A simple and reliable method for rapid extraction and determination of uranium and thorium using octadecyl-bonded silica modified with Cyanex 302 is presented. Extraction efficiency and the influence of various parameters such as aqueous phase pH, flow rate of sample solution and amount of extractant has been investigated. The study showed that the extraction of uranium and thorium increase with increasing pH value and was found to be quantitative at pH 6; and the retention of ions was not affected significantly by the flow rate of sample solution. The extraction percent were found to be 89.55 and 86.27 % for uranium and thorium, respectively. The maximal capacity of the cartridges modified by 30 mg of Cyanex 302 was found to be 20 mg of uranium and thorium. The method was successfully applied to the extraction and determination of uranium and thorium in aqueous solutions. The percentage recovery of uranium and thorium in a number of natural as well as seawater samples of Iran were also investigated and found to be in the range of 85-95%. (author)

  13. Spectrophotometric determination of uranium with arsenazo previous liquid-liquid extraction and colour development in organic medium

    International Nuclear Information System (INIS)

    Palomares Delgado, F.; Vera Palomino, J.; Petrement Eguiluz, J. C.

    1964-01-01

    The determination of uranium with arsenazo is hindered by a great number of cation which form stable complexes with the reactive and may given rise to serious interferences. By studying the optimum conditions of uranium the extraction be means of tributylphosphate solutions dissolved in methylisobuthylketone, under conditions for previous masking of the interfering cations, an organic extract was obtained containing all the uranium together with small amounts of iron. The possible interference derived from the latter element is avoided by reduction with hydroxylammoniumchlorid followed by complex formation of the Fe(II)-ortophenantroline compound in alcoholic medium. (Author) 17 refs

  14. Studies of the chemical equilibria in the solvent extraction of uranium

    International Nuclear Information System (INIS)

    Bae, K.S.; Chung, K.S.; Yang, H.B.; Kim, B.W.

    1980-01-01

    Uranium was extracted with amines dissolved in diluents. Using alamine 336 as an extractant, dodecane as a diluent, and n-octanol as an additive for third phase inhibition, UO 2 ++ extraction from H 2 SO 4 -Na 2 SO 4 aqueous solutions was studied. When the extraction coefficient of uranium was plotted as a function of the initial Na 2 SO 4 concentration at a constant sulfuric acid concentration, the typical initial spike type extraction curve was obtained in this case too. Thus, at low Na 2 SO 4 concentrations, a reaction such as UO 2 SO 4 + 2 (AlamineH) 2 SO 4 reversible (AlamineH) 4 UO 2 (SO 4 ) 3 ...(1) is believed to take place, while at high Na 2 SO 4 concentrations reaction (2) is thought to be occurring. UO 2 (SO 4 ) 3 4- + 2(R 3 NH) 2 SO 4 reversible (R 3 NH) 4 UO 2 (SO 4 ) 3 = 2SO 4 -2 ...(2). The same result obtained with Na 2 SO 4 as with H 2 SO 4 is explained by the action of sulfate ions

  15. Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Li-Jung [Marine; Pan, Horng-Bin [Department; Wai, Chien M. [Department; Byers, Margaret F. [Nuclear; Schneider, Erich [Nuclear; Strivens, Jonathan E. [Marine; Janke, Christopher J. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States; Das, Sadananda [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States; Mayes, Richard T. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States; Wood, Jordana R. [Marine; Schlafer, Nicholas [Marine; Gill, Gary A. [Marine

    2017-09-29

    The ability to re-use amidoxime-based polymeric adsorbents is a critical component in reducing the overall cost of the technology to extract uranium from seawater. This report describes an evaluation of adsorbent reusability in multiple re-use (adsorption/stripping) cycles in real seawater exposures with potassium bicarbonate (KHCO3) elution using several amidoxime-based polymeric adsorbents. The KHCO3 elution technique achieved ~100% recovery of uranium adsorption capacity in the first re-use. Subsequent re-uses showed significant drops in adsorption capacity. After the 4th re-use with the ORNL AI8 adsorbent, the 56-day adsorption capacity dropped to 28% of its original capacity. FTIR spectra revealed that there was a conversion of the amidoxime ligands to carboxylate groups during extended seawater exposure, becoming more significant with longer the exposure time. Ca and Mg adsorption capacities also increased with each re-use cycle supporting the hypothesis that long term exposure resulted in converting amidoxime to carboxylate, enhancing the adsorption of Ca and Mg. Shorter seawater exposure (adsorption/stripping) cycles (28 vs. 42 days) had higher adsorption capacities after re-use, but the shorter exposure cycle time did not produce an overall better performance in terms of cumulative exposure time. Recovery of uranium capacity in re-uses may also vary across different adsorbent formulations. Through multiple re-use the adsorbent AI8 can harvest 10 g uranium/kg adsorbent in ~140 days, using a 28-day adsorption/stripping cycle, a performance much better than would be achieved with a single use of the adsorbent through very long-term exposure (saturation capacity = 7.4 g U/kg adsorbent). A time dependent seawater exposure model to evaluate the cost associated with reusing amidoxime-based adsorbents in real seawater exposures was developed. The cost to extract uranium from seawater ranged from $610-830/kg U was predicted. Model simulation suggests that a short

  16. Bioremediation of Uranium-Contaminated Groundwater using Engineered Injection and Extraction

    Science.gov (United States)

    Greene, J. A.; Neupauer, R.; Ye, M.; Kasprzyk, J. R.; Mays, D. C.; Curtis, G. P.

    2017-12-01

    During in-situ remediation of contaminated groundwater, a treatment chemical is injected into the contaminated groundwater to react with and degrade the contaminant, with reactions occurring where the treatment chemical contacts the contaminant. Traditional in-situ groundwater remediation relies on background groundwater flow for spreading of treatment chemicals into contaminant plumes. Engineered Injection and Extraction (EIE), in which time-varying induced flow fields are used to actively spread the treatment chemical into the contaminant plume, has been developed to increase contact between the contaminant and treatment chemical, thereby enhancing contaminant degradation. EIE has been investigated for contaminants that degrade through irreversible bimolecular reaction with a treatment chemical, but has not been investigated for a contaminant governed by reversible reactions. Uranium primarily occurs in its aqueous, mobile form, U(VI), in the environment but can be bioreduced to its sparingly soluble, immobile form, U(IV), by iron reducing bacteria stimulated by an acetate amendment. In this study, we investigate the ability of EIE to facilitate and sustain favorable conditions to immobilize uranium during remediation, and to prevent re-mobilization of uranium into the aqueous phase after active remediation has ended. Simulations in this investigation are conducted using a semi-synthetic model based on physical and chemical conditions at the Naturita Uranium Mill Tailings Remedial Action (UMTRA) site in southwestern Colorado and the Old Rifle UMTRA site in western Colorado. The EIE design is optimized for the synthetic model using the Borg multi-objective evolutionary algorithm.

  17. Extraction of Uranium from Aqueous Solutions Using Ionic Liquid and Supercritical Carbon Dioxide in Conjunction

    International Nuclear Information System (INIS)

    Wang, Joanna S.; Sheaff, Chrystal N.; Yoon, Byunghoon; Addleman, Raymond S.; Wai, Chien M.

    2009-01-01

    Uranyl ions (UO2)2+ in aqueous nitric acid solutions can be extracted into supercritical CO2 (sc-CO2) via an imidazolium-based ionic liquid using tri-n-butylphosphate (TBP) as a complexing agent. The transfer of uranium from the ionic liquid to the supercritical fluid phase was monitored by UV/Vis spectroscopy using a high-pressure fiberoptic cell. The form of the uranyl complex extracted into the supercritical CO2 phase was found to be UO2(NO3)2(TBP)2. The extraction results were confirmed by UV/Vis spectroscopy and by neutron activation analysis. This technique could potentially be used to extract other actinides for applications in the field of nuclear waste management.

  18. Estimation of uranium isotope in urine samples using extraction chromatography resin

    International Nuclear Information System (INIS)

    Thakur, Smita S.; Yadav, J.R.; Rao, D.D.

    2012-01-01

    Internal exposure monitoring for alpha emitting radionuclides is carried out by bioassay samples analysis. For occupational radiation workers handling uranium in reprocessing or fuel fabrication facilities, there exists a possibility of internal exposure and urine assay is the preferred method for monitoring such exposure. Estimation of lower concentration of uranium at mBq level by alpha spectrometry requires preconcentration and its separation from large volume of urine sample. For this purpose, urine samples collected from non radiation workers were spiked with 232 U tracer at mBq level to estimate the chemical yield. Uranium in urine sample was pre-concentrated by calcium phosphate coprecipitation and separated by extraction chromatography resin U/TEVA. In this resin extractant was DAAP (Diamylamylphosphonate) supported on inert Amberlite XAD-7 support material. After co-precipitation, precipitate was centrifuged and dissolved in 10 ml of 1M Al(NO 3 ) 3 prepared in 3M HNO 3 . The sample thus prepared was loaded on extraction chromatography resin, pre-conditioned with 10 ml of 3M HNO 3 . Column was washed with 10 ml of 3M HNO 3 . Column was again rinsed with 5 ml of 9M HCl followed by 20 ml of 0.05 M oxalic acid prepared in 5M HCl to remove interference due to Th and Np if present in the sample. Uranium was eluted from U/TEVA column with 15 ml of 0.01M HCl. The eluted uranium fraction was electrodeposited on stainless steel planchet and counted by alpha spectrometry for 360000 sec. Approximate analysis time involved from sample loading to stripping is 2 hours when compared with the time involved of 3.5 hours by conventional ion exchange method. Seven urine samples from non radiation worker were radio chemically analyzed by this technique and the radiochemical yield was found in the range of 69-91 %. Efficacy of this method against conventional anion exchange technique earlier standardized at this laboratory is also being highlighted. Minimum detectable activity

  19. Comparison of total and cold-extractable uranium in stream sediments of the southwestern Karoo supergroup, South Africa

    International Nuclear Information System (INIS)

    Jakob, W.R.O.; Smit, M.C.B.; Murphy, G.C.

    1979-01-01

    In order to evaluate the usefullness of cold-extractable uranium as a tool of uranium prospecting in stream sediments of the southwestern Karoo, South Africa, ten orientation studies were conducted near known mineralisation jointly by the Atomic Energy Board and the Geological Survey of South Africa. These indicate that the topography determines the nature of the dispersion. In areas of moderate to high relief the total uranium content of the stream sediment gives dispersion trains up to about 500 m from the mineralisation, and peak-to-background ratios of about 3. The use of cold-extractable uranium doubles the length of the dispersion, and peak-to-background ratios are greater than 10 and may be as high as 35. In areas of low relief, the total uranium content of the sediment gives low anomalies, with short dispersion downstream. Cold-extractable uranium gives anomalies 500-1 000 m from the mineralisation. This is interpreted to be due to the longer residence time of the clay minerals in the stream. In order to test the applicability of cold-extractable uranium on a regional scale, 720 samples were collected at a density of one sample per square kilometre. Statistical treatment of the data shows the U content of the stream sediments, to be log-normally distributed. For cold-extractable uranium, polymodal distributions, apparently representing background and anomalous samples, can be separated with a high rate of success, and meaningful threshold values can be assigned. This is not the case for the total uranium content of the stream sediments [af

  20. Liquid-liquid extraction of uranium(VI) with cryptand-222 and Eosin as the counter ion

    International Nuclear Information System (INIS)

    Viji Jacob Mathew; Khopkar, S.M.

    1995-01-01

    Uranium(VI), (5 μg) was quantitatively extracted at pH 6.0 with 0.01M cryptand-222 in chloroform in the presence of 0.005M Eosin as the counter ion. The metal from the organic phase was stripped with 0.1M perchloric acid. Uranium(VI) from the aqueous phase was determined spectrophotometrically at 430 nm as its complex with oxine. The extraction was quantitative between pH 5.5-6.5. Nitrobenzene, chloroform and dichloromethane were the best diluents. The optimum extractant concentration was 0.01M, while that of Eosin was 0.005M. Except for perchloric acid (0.01M), other acids could not strip uranium. Uranium was separated from manganese, cadmium, lead, thallium and nickel, etc., in the multicomponent mixtures. The relative standard deviation was ±1%. (author). 18 refs., 1 fig., 6 tabs

  1. Uranium

    International Nuclear Information System (INIS)

    Perkin, D.J.

    1982-01-01

    Developments in the Australian uranium industry during 1980 are reviewed. Mine production increased markedly to 1841 t U 3 O 8 because of output from the new concentrator at Nabarlek and 1131 t of U 3 O 8 were exported at a nominal value of $37.19/lb. Several new contracts were signed for the sale of yellowcake from Ranger and Nabarlek Mines. Other developments include the decision by the joint venturers in the Olympic Dam Project to sink an exploration shaft and the release of an environmental impact statement for the Honeymoon deposit. Uranium exploration expenditure increased in 1980 and additions were made to Australia's demonstrated economic uranium resources. A world review is included

  2. Uranium

    International Nuclear Information System (INIS)

    Gabelman, J.W.; Chenoweth, W.L.; Ingerson, E.

    1981-01-01

    The uranium production industry is well into its third recession during the nuclear era (since 1945). Exploration is drastically curtailed, and many staffs are being reduced. Historical market price production trends are discussed. A total of 3.07 million acres of land was acquired for exploration; drastic decrease. Surface drilling footage was reduced sharply; an estimated 250 drill rigs were used by the uranium industry during 1980. Land acquisition costs increased 8%. The domestic reserve changes are detailed by cause: exploration, re-evaluation, or production. Two significant discoveries of deposits were made in Mohave County, Arizona. Uranium production during 1980 was 21,850 short tons U 3 O 8 ; an increase of 17% from 1979. Domestic and foreign exploration highlights were given. Major producing areas for the US are San Juan basin, Wyoming basins, Texas coastal plain, Paradox basin, northeastern Washington, Henry Mountains, Utah, central Colorado, and the McDermitt caldera in Nevada and Oregon. 3 figures, 8 tables

  3. Liquid-liquid extraction of uranium from Egyptian phosphoric acid using a synergistic D2EHPA-DBBP mixture

    International Nuclear Information System (INIS)

    Abdel-Khalek, A.A.

    2011-01-01

    Extraction of uranium from Egyptian phosphoric acid with synergistic mixture of di-2-ethylhexylphosphoric acid (D2EHPA) and di-butyl butyl phosphonate (DBBP) is reported in this paper. The influence of various factors such as D2EHPA concentration, DBBP concentration, phosphoric acid concentration, contact time, aqueous: organic phase's ratio (aq:org) and temperature on the degree of extraction has been established. The data on the effect of temperature on the extraction showed that the enthalpy change is -23.12 kJ/mol. Uranium extracted by D2EHPA- DBBP is further subjected to a second cycle of extraction and scrubbing impurities. The uranium is finally converted to a high purity UO 3 product using precipitation with hydrogen peroxide and heat treatment at 375 deg C. (author)

  4. Extractive scintillating polymer sensors for trace-level detection of uranium in contaminated ground water.

    Science.gov (United States)

    Duval, Christine E; DeVol, Timothy A; Husson, Scott M

    2016-12-01

    This contribution describes the synthesis of robust extractive scintillating resin and its use in a flow-cell detector for the direct detection of uranium in environmental waters. The base poly[(4-methyl styrene)-co-(4-vinylbenzyl chloride)-co-(divinylbenzene)-co-(2-(1-napthyl)-4-vinyl-5-phenyloxazole)] resin contains covalently bound fluorophores. Uranium-binding functionality was added to the resin by an Arbuzov reaction followed by hydrolysis via strong acid or trimethylsilyl bromide (TMSBr)-mediated methanolysis. The resin was characterized by Fourier-transform infrared spectroscopy and spectrofluorometry. Fluorophore degradation was observed in the resin hydrolyzed by strong acid, while the resin hydrolyzed by TMSBr-mediated methanolysis maintained luminosity and showed hydrogen bonding-induced Stokes' shift of ∼100 nm. The flow cell detection efficiency for uranium of the TMSBr-mediated methanolysis resin was evaluated at pH 4, 5 and 6 in DI water containing 500 Bq L -1 uranium-233 and demonstrated flow cell detection efficiencies of 23%, 16% and 7%. Experiments with pH 4, synthetic groundwater with 50 Bq L -1 uranium-233 exhibited a flow cell detection efficiency of 17%. The groundwater measurements show that the resins can concentrate the uranyl cation from waters with high concentrations of competitor ions at near-neutral pH. Findings from this research will lay the groundwork for development of materials for real-time environmental sensing of alpha- and beta-emitting radionuclides. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Extraction/fluorometric determination of uranium with rhodamine B and 2-thenoyltrifluoroacetone

    International Nuclear Information System (INIS)

    Naganuma, Takeshi; Tuzuki, Satoshi; Jin, Jiye.

    1990-01-01

    A method for the fluorometric determination of uranium, based on a solvent extraction of an ion associate formed between Rhodamine B cation and 2-thenoyltrifluoroacetone(TTA)-metal chelate anion with benzene, is described. The procedure for the construction of the calibration curve is as follows. Varying amounts of uranium standard solution and 2 ml of 2 M ammonium acetate buffer solution are mixed. The solution is adjusted at pH 6.0 and 10 ml of 0.3 % Rhodamine B are added. It is then shaken for 5 min with 10 ml of 0.01 M TTA benzene solution. The fluoresence of the organic phase is measured at 545 nm (excitation) and 570 nm (emission) for uranyl-TTA-Rhodamine B complex. The fluorescence intensity is linearly related to the concentration of uranyl ion in the range of 0.05 ppm ot 1 ppm. (author)

  6. Design and evaluation of hybrid meso-porous silicas to uranium extraction from sulfuric media

    International Nuclear Information System (INIS)

    Charlot, Alexandre

    2016-01-01

    Nuclear industries are perpetually looking for technical, economic and environmental progresses. Important volumes of acidic waste are generated by nuclear plants of the front end. The extraction of uranium from these solutions is required to decontaminate effluents (decrease of the radioactivity) and value uranium (re-incorporation in the cycle). Uranium leaching is mostly achieved using sulfuric acid leading to the production of aqueous effluents that contain a large grade of sulfate complexes. In such conditions, uranyl sulfate complexes constitute the predominant uranium species in solution and its extraction represents a real scientific and technological challenge. Commonly, precipitation, solvent extraction or solid phase extraction are used. The last one is particularly adapted for low grade solutions due to it weak environmental footprint (no solvent are handling) and the facility of the process involved (i.e. fixed bed column). among the available solid-phase extraction candidates, hybrid meso-porous silicas get a crucial part. They develop a very high specific surface areas and a driven porosity which give them a high potential of extraction capacities. In this manuscript the tailoring and the evaluation of hybrid meso-porous silicas have been investigated. Firstly, the work focus on the organic part grafted by post-synthetic pathway, the N,N-dialkyl-carbamoyl-phosphonate based molecules have been identified to get interesting extraction properties. This study emphasizes that acid groups are required and that alkyl substituents get a real importance in the extraction efficiency. On the second hand, the role of pore size has been investigated. The results obtained disclosed that pores size diameters directly impact the grafting ratio as well as the homogeneity of the material: (1) materials with a pore size below 3 nm are heterogeneously functionalized due to steric issues, (2) a homogeneous organic monolayer grafted onto the silica skeleton occurs when

  7. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Recent decisions by the Australian Government will ensure a significant expansion of the uranium industry. Development at Roxby Downs may proceed and Ranger may fulfil two new contracts but the decision specifies that apart from Roxby Downs, no new mines should be approved. The ACTU maintains an anti-uranium policy but reaction to the decision from the trade union movement has been muted. The Australian Science and Technology Council (ASTEC) has been asked by the Government to conduct an inquiry into a number of issues relating to Australia's role in the nuclear fuel cycle. The inquiry will examine in particular Australia's nuclear safeguards arrangements and the adequacy of existing waste management technology. In two additional decisions the Government has dissociated itself from a study into the feasibility of establishing an enrichment operation and has abolished the Uranium Advisory Council. Although Australian reserves account for 20% of the total in the Western World, Australia accounts for a relatively minor proportion of the world's uranium production

  8. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The French Government has decided to freeze a substantial part of its nuclear power programme. Work has been halted on 18 reactors. This power programme is discussed, as well as the effect it has on the supply of uranium by South Africa

  9. Sorption, desorption and extraction of uranium from some sands under dynamic conditions

    International Nuclear Information System (INIS)

    Palagyi, S.; Laciok, A.

    2006-01-01

    Sorption, desorption and extraction behavior of uranium in various fluvial sands of domestic origin were investigated in continuous dynamic column experiments. For the sorption of U(VI) an aqueous 10 -4 M UO 2 (NO 3 ) 2 solution was used at a flow rate of about 0.3 cm 3 /min. Desorption was carried out with demineralized water, and the extraction with 10 -2 M Na 2 CO 3 solution following desorption. The retardation coefficients (R) and hydrodynamic dispersion coefficients (D d ), were determined using an ADE equation. From the experimentally determined values of R, bulk density and porosity, the distribution coefficients (K d ) of the UO 2 2+ species have been calculated for the respective processes. The extent of U sorption in sands, as well as the proportion of desorbed and extracted U from these sands, was also calculated. (author)

  10. Uranium, neptunium and plutonium kinetics of extraction by tributylphosphate and trilaurylamine in a centrifugal contactor

    International Nuclear Information System (INIS)

    Bergeonneau, P.; Jaouen, C.; Germain, M.; Bathellier, A.

    1977-01-01

    Uranium, plutonium and neptunium kinetics of transfer between various aqueous nitric solutions and solvents have been measured at the laboratory scale, using a centrifugal contactor especially developed in the laboratory. The transfer kinetics of nitric acid, hexavalent U, tetravalent U, Np and Pu from nitric acid solutions into 30% TBP in r-dodecane and 10% trilaurylamine in r-dodecane have been studied. The effects of rotation speed, temperature, initial nitric acid concentration, metal concentration on extraction and stripping kinetics have been investigated. The results obtained show that TBP extraction and stripping are more rapid than trilaurylamine ones. The low activation energies of transfer reactions with TBP suggest that both in extraction and stripping, the transfer rate is limited by the diffusion of the species in the aqueous and organic phases. For trilaurylamine, the transfer mechanism appears more complex

  11. Comparison of solvent extraction and extraction chromatography resin techniques for uranium isotopic characterization in high-level radioactive waste and barrier materials.

    Science.gov (United States)

    Hurtado-Bermúdez, Santiago; Villa-Alfageme, María; Mas, José Luis; Alba, María Dolores

    2018-07-01

    The development of Deep Geological Repositories (DGP) to the storage of high-level radioactive waste (HLRW) is mainly focused in systems of multiple barriers based on the use of clays, and particularly bentonites, as natural and engineered barriers in nuclear waste isolation due to their remarkable properties. Due to the fact that uranium is the major component of HLRW, it is required to go in depth in the analysis of the chemistry of the reaction of this element within bentonites. The determination of uranium under the conditions of HLRW, including the analysis of silicate matrices before and after the uranium-bentonite reaction, was investigated. The performances of a state-of-the-art and widespread radiochemical method based on chromatographic UTEVA resins, and a well-known and traditional method based on solvent extraction with tri-n-butyl phosphate (TBP), for the analysis of uranium and thorium isotopes in solid matrices with high concentrations of uranium were analysed in detail. In the development of this comparison, both radiochemical approaches have an overall excellent performance in order to analyse uranium concentration in HLRW samples. However, due to the high uranium concentration in the samples, the chromatographic resin is not able to avoid completely the uranium contamination in the thorium fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

    International Nuclear Information System (INIS)

    Chaiko, D.J.; Gartelmann, J.; Henriksen, J.L.; Krause, T.R.; Deepak; Vojta, Y.; Thuillet, E.; Mertz, C.J.

    1995-07-01

    The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethlene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests with soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided

  13. Design of mixer settler extraction cycles II for recovery uranium from phosphoric acid

    International Nuclear Information System (INIS)

    Abdul Jami; Hafni Lissa Nuri

    2013-01-01

    Mixer settler is technically designed for extraction and separation process of uranium from phosphoric acid solution. Design calculation results shows that: the mixer settler consists of two parts: part of extraction process in the mixer tank and part of separation process in settler tank. The mixer tank type of box with 4 baffles, the size of mixer tank, 0.8 m width, 0.8 m length, 1 m high of liquid, 1.05 m high of mixer tank, stirrer type of disk 6 blade, and power of mixing 4 hp and the settler tank type of rectangular with size of settler tank, 0.8 m width 5 m length, 1 m high of liquid, 1.05 m high of settler tank. For uranium recovery efficiency up to 91%, extraction process is done in 3 stage counter current flow using a solvent Organic (O) DEHPA-TOPO in Kerosene at a phase of ratio A/O of 2:1. The aqueous enter through stage 3 and the organic solvent enter through stage 1. The process of settling occurred with the value of settling velocity is 0.000694 m/s, dispersion factor Ψ = 0.3638 and the light fraction as the dispersed phase and value of Reynolds number (NRE) = 3,438. Because of the Reynolds number is lower than 5,000, it indicates that the quality of the separation is very good. (author)

  14. Extraction of uranium(VI) by emulsion liquid membrane containing 5,8-diethyl-7-hydroxy-6-dodecanone oxime

    International Nuclear Information System (INIS)

    Akiba, Kenichi; Takahashi, Toshihiko; Kanno, Takuji

    1984-01-01

    Extraction of uranium(VI) by a liquid surfactant membrane has been studied. The stability of water-in-oil (w/o) emulsion dispersed in the continuous aqueous phase increased with an increase in surfactant concentrations and in the fraction of the organic phase in emulsion globules. Uranium(VI) in dilute acid solutions was extracted into (w/o) emulsions containing 5,8-diethyl-7-hydroxy-6-dodecanone oxime (LIX 63) as a mobile carrier and its concentration decreased according to [U]sub(t)=[U]sub(o)exp(-ksub(obsd)t). The apparent rate constants (ksub(obsd)) increased with an increase in carrier concentrations and in external pH values, while they were slightly dependent on the stripping acid concentrations. Uranium was transported and concentrated into the internal aqueous droplets. The final concentration of uranium in the external aqueous phase dropped to about 10 -3 of its initial value. (author)

  15. Separation and concentration of uranium by extraction chromatography : U(VI) - H/sub 3/PO/sub 4/ system

    Energy Technology Data Exchange (ETDEWEB)

    Nobre, J S.M.

    1981-01-01

    The feasibility of using the extraction chromatographic technique as a way to recover uranium from phosphatic rocks is evaluated. The behaviour of uranium from raw phsophoric acid solutions in chromatographic systems using the mixture di(2-ethylhexyl) orthophosphoric acid (D2EHPA) - tributyl phosphate (TBP) as the stationary phase was studied. Materials as alumina, activated carbon and the macroporous resins XAD-4 and XAD-7 were used as supports for organic stationary phase. The best results were obtained with poliacrilic polymer XAD-7, due to its excellent chromatographic properties and efficient organic phase retention. Uranium was quantitatively retained by D2EHPA-TBP-XAD-7 columns from synthetic phosphoric acid solutions with typical composition of phosphatic acid liquors. The elution of uranium from this system was also studied, and the best results were obtained with phosphoric acid solutions. This chromatographic column presented a high stability, not changing their properties even after more than twenty cycles, including the conditioning, sorption, washing and elution steps. Uranium determinations were perfpormed by indirect titration with potassium dichromate and by molecular absorption spectrophotometry with hydrogen peroxide- carbonate. A new and more sensitive method for uranium determination in phosphoric medium, which might be applied to acid liquors of phosphatic ores, was developed. An extraction-photometric method was used, with Arsenazo III (1,8-dihydroxynaphtalene-3,6-disulphonic acid-2,7-bis(azo-2)-phenylarsonic acid) as the reagent for uranium.

  16. Acid-curing and ferric-trickle leaching effluent used in closed circuit uranium extractive process

    International Nuclear Information System (INIS)

    Jin Suoqing; Xiang Qinfang; Guo Jianzheng; Lu Guizhu; Su Yanru

    1998-01-01

    The new uranium ore process consists of crushing ore, mixing crushed ore with strong acid in rotating drums and curing the mixture in piles, trickle-leaching the ore beds with ferric solution, extracting uranium from pregnant solution with tertiary amine, precipitating product and disposing residue tailings. All the process effluent is used in closed circuit. There will be no process water to be discharged in the flowsheet except the tailings carrying off 15% water because during leaching moisture content of the ore rises to 15%. Tailings produced by the process are moist and friable, and can be disposed of on a pile or returned to the mine. Main technical parameters of the process: (a) water consumption is 0.2∼0.3 m 3 /t ore, electric power consumption is 20∼30 kW·h/t ore; (b) ore crushing up to -5∼-7 mm, leaching period is 12∼45 d, U content of residue is 0.01%∼0.02%, producing pregnant solution is 0.3∼0.5 m 3 /t ore, which is 1/5∼1/8 that of conventional agitation leaching process; (c) organic agent consumption is 1/5∼1/8 that of the conventional agitation process. All the research results above are tested by the pilot-plant test and industrial test. The new process has been applied to recovery of uranium in the mine located at northeast of China

  17. Simultaneous determinations of uranium, thorium, and plutonium in soft tissues by solvent extraction and alpha-spectrometry

    International Nuclear Information System (INIS)

    Singh, N.P.; Zimmerman, C.J.; Lewis, L.L.; Wrenn, M.E.

    1984-01-01

    A radiochemical procedure for the simultaneous determination of uranium, thorium, and plutonium, in soft tissues has been developed. The weighed amounts of tissues, spiked with 232 U, 242 Pu, and 229 th tracers, are wet ashed. Uranium, thorium, and plutonium are coprecipitated with iron as hydroxides, dissolved in concentrated HCl and the acidity adjusted to 10 M. Uranium and plutonium are extracted into 20% TLA solution in xylene, leaving thorium in the aqueous phase. Plutonium is back-extracted by reducing to the trivalent state with 0.05 M NH 4 I solution in 8 M HCl, and uranium is back-extracted with 0.1 M HCl. Thorium is extracted into 20% TLA solution from 4 M HNO 3 and back-extracted with 10 M HCl. Uranium, thorium and plutonium are electrodeposited separately onto platinum discs and counted alpha-spectrometrically using surface barrier silicon diodes and a multichannel analyzer. The method was developed using bovine liver and applied to dog and human tissues. The mean radiochemical recoveries of these actinides in different organs were better than 70%. 6 references, 2 tables

  18. Analysis of prospecting effect of polonium survey and geoelectric survey extracted uranium and molybdenum in the south of Shengyuan volcanic basin

    International Nuclear Information System (INIS)

    Jin Hehai

    2007-01-01

    Polonium survey and geoelectric survey extracted uranium and molybdenum show that compound anomaly with sharp anomaly peak of the curve of polonium-210, uranium, molybdenum appears along many survey lines in Bakou area, Shengyuan volcanic basin, which may reflect the enrichment of uranium and molybdenum in rock formation and soil layer. By contrasting the anomaly curve to that above the buried uranium deposit, it is recognized that compound anomaly is closely related to the uranium mineralization condition in the area and some favourable sites for uranium metallogeny have been predicated. (authors)

  19. Occurrence of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in uranium mine-Caldas uranium mining and extraction plant, Brazil (CUMEP)

    International Nuclear Information System (INIS)

    Gomes, H.A.; Garcia, O.; Gomes, J.E.; Rabello, E.; Cannavan, F.S.; Tsai, S.M.

    2005-01-01

    The sulfated minerals present in mining areas may cause serious environmental problems due to the action of chemolithotrophic bacteria from genus Acithiobacillus, represented mainly by Acithiobacillus ferrooxidans and Acithiobacillus thiooxidans. These microorganisms are able to oxidize mineral sulfates, elementary sulfur and ferrous ion (A. ferrooxidans), as well are capable of mobilizing radionuclide as uranium to the environment. In this context, this study aimed at investigating the occurrence and the fluctuation of A. ferrooxidans and A. thiooxidans populations within the mine effluents, tailing dam and waste rocks of the Caldas Uranium Mining arid Extraction Plant (CUMEP) in Minas Gerais State - Brazil. Samples from 16 sites were evenly taken monthly in the CUMEP, during 28 months. The oxi-reduction potential, pH and temperature values were determined at the Radioecology Laboratory. The Most Probable Number technique was applied using a series of five tubes for selective counting of A. ferrooxidans and A. thiooxidans. Each sample was submitted to serial dilutions using Tween 80 and sterilized water (pH=2.0) and subsequently transferred into assay tubes containing T and K with ferrous ion and also elementary sulfur, as energy source, for detection of A. ferrooxidans and A. thiooxidans, respectively. Populations of A. ferrooxidans and A. thiooxidans presented seasonal quantitative fluctuations at the different studied sites. A. ferrooxidans showed higher or equal frequency to that observed for A. thiooxidans; as consequence, they were considered the predominant bacteria in this environment. In the majority of the sites, the highest values for the frequency and counting of A. ferrooxidans and A. thiooxidans were observed during the rainy period (October to March). The relative seasonal behavior when several variables are evaluated simultaneously indicated that, due to the high values of oxi-reduction potential, the low values of pH, the detection of the highest

  20. Chloride pyrometallurgy of uranium ore. 2. Selective extraction of uranium using the mixed gas of chlorine and oxygen in the presence of activated carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1996-01-01

    Selective extraction of uranium from a phosphate ore was studied by using the mixed gas of Cl 2 and O 2 . On heating the ore and carbon mixture in Cl 2 , the volatilized chloride of uranium is accompanied by iron, aluminum, phosphorus and silicon chlorides. The addition of O 2 gas effectively lowered the volatilization ratios of aluminum, phosphorus and silicon. The ratio decreased with increasing oxygen flow rate up to 50 ml/min at 1,223 K (Cl 2 : 100 ml/min, O 2 +N 2 : 400 ml/min). The volatilization ratio of uranium was almost unchanged at 90% up to 50 ml/min O 2 (carbon amount: 15 wt%). The effect of the other parameters, i.e. Cl 2 flow rate, carbon amount, reaction temperature and time was examined. (author)

  1. The TRUEX [TRansUranium EXtraction] process and the management of liquid TRU [transuranic] waste

    International Nuclear Information System (INIS)

    Schulz, W.W.; Horwitz, E.P.

    1987-01-01

    The TRUEX process is a new generic liquid-liquid extraction process for removal of all actinides from acidic nitrate or chloride nuclear waste solutions. Because of its high efficiency and great flexibility, the TRUEX process appears destined to be widely used in the US and possibly in other countries for cost-effective management and disposal of transuranic (TRU) wastes. In the US, TRU wastes are those that contain ≥3.7 x 10 6 Bq/kg) of TRU elements with half-lives greater than 20 y. This paper gives a brief review of the relevant chemistry and summarizes the current status of development and deployment of the TRUEX (TRansUranium EXtraction) process flowsheets to treat specific acidic waste solutions at several US Department of Energy sites. 19 refs., 4 figs., 4 tabs

  2. Liquid-liquid extraction of uranium(VI) using Cyanex 272 in toluene from sodium salicylate medium

    International Nuclear Information System (INIS)

    Madane, Namdev S.; Nikam, Gurunath H.; Jadhav, Deepali V.; Mohite, Baburao S.

    2011-01-01

    Liquid-liquid extraction of U(VI) from sodium salicylate media using Cyanex 272 in toluene has been carried out. Uranium(VI) was quantitatively extracted from 1 x 10 -3 M sodium salicylate with 5 x 10 -4 M Cyanex 272 in toluene. It was stripped quantitatively from the organic phase with 1M HCl and determined spectrophotometrically with arsenazo(III) at 660 nm. The effect of concentrations of sodium salicylate, extractant, diluents, metal ion and strippants have been studied. Separation of uranium(VI) from other elements was achieved from binary as well as from multicomponent mixtures. The method was extended to determination of uranium(VI) in geological samples. The method is simple, rapid and selective with good reproducibility (approximately ± 2%). (author)

  3. Characterization of molybdenum interfacial crud in a uranium mill that employs tertiary-amine solvent extraction

    International Nuclear Information System (INIS)

    Moyer, B.; McDowell, W.J.

    1983-01-01

    In the present work, samples of a molybdenum-caused green gummy interfacial crud from an operating western US uranium mill have been physically and chemically examined. Formaton of cruds of this description has been a long-standing problem in the use of tertiary amine solvent extraction for the recovery of uranium from low-grade ores (Amex Process). The crud is essentially an organic-continuous dispersion containing about 10 wt % aqueous droplets and about 37 wt % greenish-yellow crystalline solids suspended in kerosene-amine process solvent. The greenish-yellow crystals were found to be a previously unknown double salt of tertiary amine molybdophosphate with three tertiary amine chlorides having the empirical formula (R 3 NH) 3 [PMo 12 O 40 ].3(R 3 NH)Cl. To confirm the identification of the compound, a pure trioctylamine (TOA) analog was synthesized. In laboratory extraction experiments, it was demonstrated that organic-soluble amine molydophosphate forms slowly upon contact of TOA solvent with dilute sulfuric acid solutions containing low concentrations of molybdate and phosphate. If the organic solutions of amine molybdophosphate were then contacted with aqueous NaCl solutions, a greenish-yellow precipitate of (TOAH) 3 [PMo 12 O 40 ].3(TOAH)Cl formed at the interface. The proposed mechanism for the formation of the crud under process conditions involves build up of molybdenum in the solvent, followed by reaction with extracted phosphate to give dissolved amine molybdophosphate. The amine molybdophosphate then co-crystallizes with amine chloride, formed during the stripping cycle, to give the insoluble double salt, which precipitates as a layer of small particles at the interface. The proposed solution to the problem is the use of branched-chain, instead of straight-chain, tertiary amine extractants under the expectation that branching would increase the solubility of the double salt. 2 figures, 5 tables

  4. Extraction of prospecting information of uranium deposit based on high spatial resolution satellite data. Taking bashibulake region as an example

    International Nuclear Information System (INIS)

    Yang Xu; Liu Dechang; Zhang Jielin

    2008-01-01

    In this study, the signification and content of prospecting information of uranium deposit are expounded. Quickbird high spatial resolution satellite data are used to extract the prospecting information of uranium deposit in Bashibulake area in the north of Tarim Basin. By using the pertinent methods of image processing, the information of ore-bearing bed, ore-control structure and mineralized alteration have been extracted. The results show a high consistency with the field survey. The aim of this study is to explore practicability of high spatial resolution satellite data for prospecting minerals, and to broaden the thinking of prospectation at similar area. (authors)

  5. Separation of uranium from aqueous solutions using calix[6]arenes in liquid-liquid extraction as well as solid phase extraction

    International Nuclear Information System (INIS)

    Schmeide, K.; Geipel, G.; Bernhard, G.

    2004-11-01

    The suitability of different calyx[n] arene types for uranyl extraction from liquid solutions was examined by means of liquid-liquid extraction using aqueous phases and organic solvents of varying compositions. It was found that COOH-derivatised calyx[6] arenes have good extraction properties and can even be used in the acid pH range. The use of calixarene-modified fleeces for the separation of uranyl from aqueous phases was examined in batch experiments with pH and uranyl concentration as variables and in the presence or absence of competing ions. The results showed that calixarene-modified fleeces can be used for uranium separation starting from pH 4. At pH 5, up to a maximum of 7.6 x 10 -7 mol uranium can be bound per 1 g of calixarene-modified fleece. The separation of uranyl from synthetic pit waters was examined as a means of testing the separation capacity of calixarene-modified fleeces in environmentally sensitive waters. Studies on the reversibility of uranium bonding to calixarene-treated polyester fleeces have shown that under environmentally realistic conditions (neutral pH range) the uranium is firmly bound to the calixarene-modified fleeces and cannot be mobilised. By contrast, in acidic environments calixarene-modified fleeces are capable of near-complete regeneration. Such regenerated textile filter materials can then be used for further uranium separation cycles [de

  6. Extraction of uranium and lead from mixed waste debris using a variety of metal/ligand complexes

    International Nuclear Information System (INIS)

    Needham, D.A.; Duran, B.L.; Ehler, D.S.; Sauer, N.N.

    1997-01-01

    To ensure the safety of our Nation's nuclear stockpile, Los Alamos National Laboratory is in the process of constructing the DARHT (Dual Axis Radiographic Hydrodynamic Test) facility. DARHT will examine the effects of aging and the stability of our stockpile. Contained testing will be phased in to reduce the impact of these tests, which contain depleted uranium, on our environment. The main focus of this research is to develop a treatment scheme for the recovery of depleted uranium and lead from shot debris that will result from these tests. The goals of this research are to optimize the conditions on a bench scale using a commercially available water soluble polymer to bind the lead and a variety of metal/ligand complexes such as 4,5-dihydroxy-1,3-benzene-disulfonic acid, dithionite, sodium carbonate/bicarbonate, and sodium hypochlorite to bind the uranium. Studies were conducted on a mixture of debris, such as wood, cable, paper towels, and tubing that contained both uranium and lead ranging in concentration from 10-1000's of ppm of contaminants. Experiments were done varying combinations and successions of extractant solutions as well as a number of sequential extractions. Studies show that a mixture of sodium hypochlorite and carbonate removed 90+% of both uranium and lead. We then focused on a separation scheme for the lead and uranium

  7. Extraction of uranium from coarse ore and acid-curing and ferric sulphate-trickle leaching process

    International Nuclear Information System (INIS)

    Jin Suoqing

    1994-01-01

    On the basis of analysis of the problems in the technology of the traditional uranium hydrometallurgy and the limitations of thin layer leaching process (TLL), a new leaching system-acid-curing and ferric sulphate-trickle leaching (AFL) process (NGJ in Chinese) has developed for extraction of uranium from the coarse ore. The ferric sulphate solution was used for trickling the acid-cured uranium ore and the residual leaching reaction incomplete in TLL process can be improved in this process. And the AFL process has a wide applicability to China's uranium ores, being in competition with the traditional agitation leaching process for treating coarse ores. The uranium ore processing technology based on the AFL process will become one of the new basic technologies of uranium hydrometallurgy. A series of difficulties will be basically overcome associated with fine grinding because of its elimination in the presented process. Moreover, the situation of the present uranium hydrometallurgy can be also changed owing to without technological effluent discharge

  8. An ICP-AES method for the determination of trace metals in uranium by solvent extraction using KSM-17

    International Nuclear Information System (INIS)

    Jacob, Mary; Radhakrishnan, K.; Dhami, P.S.; Kulkarni, V.T.; Joshi, M.V.; Patwardhan, A.B.; Ramanujam, A.; Mathur, J.N.

    1994-01-01

    This paper describes the studies carried out for the determination of trace metallic impurities in uranium solutions. Uranium matrix is separated from the impurity elements by its selective extraction using 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC88A). The aqueous phase is analysed for trace impurities by inductively coupled argon plasma atomic emission spectrometry. The studies also include recovery of impurities at various acidities and spectral interferences of uranium over the analyte element channels. Based on the above studies, a method has been standardised for the analysis of nineteen elements in uranium solutions. The relative standard deviation of the method for various elements is in the range of +- 1-5%. (author). 7 refs., 8 tabs., 1 fig

  9. Trace recovery of uranium and rare earth contained in phosphates by liquid-liquid extraction in sulfuric attack liquor

    International Nuclear Information System (INIS)

    Bousquet, F.; Foraison, D.; Leveque, A.; Sabot, J.L.

    1980-06-01

    Uranium and rare earths can be recovered in sedimentary phosphates during the wet processing of the ore by sulfuric acid giving raw phosphoric acid at 30 per cent of P 2 O 5 . Practically all the uranium contained and only part of rare earths are put into solution in this treatment. Separation of these elements in the phosphoric solution is obtained by liquid-liquid extraction with alkylphosphoric acids and especially with their mono and di esters. Partition isotherms are determined and counter-current tests are effected. Uranium and rare earths reextraction from these solvents can be simultaneous or separate with aqueous solutions alkaline or containing HF or by antisynergism. Pros and cons of each reextraction process are discussed. In conclusion HDEHP or OPPA are recommended because of availability, stability and hydrodynamic, OPPA less selective with rare earths allows the recovery with uranium of ceric earths, yttrium and yttric earths [fr

  10. Process engineering challenges of uranium extraction from phosphoric acid on industrial scale

    International Nuclear Information System (INIS)

    Mouriya, Govind; Singh, Dhirendra; Nath, A.K.; Majumdar, D.

    2014-01-01

    Heavy Water Board (HWB) is a constituent unit of the Department of Atomic Energy. One of the diversified activities undertaken by HWB is pursuing exploitation of non-conventional resources for recovery of uranium from wet phosphoric acid being the most prominent one. Amongst the feasible processes for recovery of uranium from phosphoric acid is solvent extraction. Use of in-house solvent produced by HWB, is another key driver. To garner necessary information for developing the industrial scale facilities, the process has been studied in the laboratory scale, mini scale, bench scale at Heavy Water Plant, Talcher. The process was subsequently scaled up to an industrial prototype scale unit and was set up as a Technology Demonstration Plant coupled with a commercial phosphoric acid plant. The plant has successfully processed more than 2 lakh m 3 of wet phosphoric acid and all the parameters including the product, Yellow Cake have been qualified. No adverse effect has been observed in the fertilizer produced. The main characteristics of the process and subsequent process innovations are discussed in this paper. These innovations have been carried out to overcome hurdles faced during commissioning and subsequent operations of the Plant. The innovations include improved pretreatment of the wet phosphoric acid for feeding to the extraction cycle, improved control of the first cycle chemical environment, reducing the strength of the phosphoric acid used for stripping, reducing the number of equipment and machineries, alteration in solvent composition used in the first and second cycle in the solvent extraction units of the plant. (author)

  11. Uranium

    International Nuclear Information System (INIS)

    Battey, G.C.; McKay, A.D.

    1988-01-01

    Production for 1986 was 4899 t U 3 O 8 (4154 t U), 30% greater than in 1985, mainly because of a 39% increase in production at Ranger. Exports for 1986 were 4166 t U 3 O 8 at an average f.o.b. unit value of $40.57/lb U 3 O 8 . Private exploration expenditure for uranium in Australia during the 1985-86 fiscal year was $50.2 million. Plans were announced to increase the nominal capacity of the processing plant at Ranger from 3000 t/year U 3 O 8 to 4500 t and later to 6000 t/year. Construction and initial mine development at Olympic Dam began in March. Production is planned for mid 1988 at an annual rate of 2000 t U 3 O 8 , 30 000 t Cu, and 90 000 oz (2800 kg) Au. The first long-term sales agreement was concluded in September 1986. At the Manyingee deposit, testing of the alkaline solution mining method was completed, and the treatment plant was dismantled. Spot market prices (in US$/lb U 3 O 8 ) quoted by Nuexco were generally stable. From January-October the exchange value fluctuated from US$17.00-US$17.25; for November and December it was US$16.75. Australia's Reasonably Assured Resources of uranium recoverable at less than US$80/kg U at December 1986 were estimated as 462 000 t U, 3000 t U less than in 1985. This represents 30% of the total low-cost RAR in the WOCA (World Outside the Centrally Planned Economy Areas) countries. Australia also has 257 000 t U in the low-cost Estimated Additional Resources Category I, 29% of the WOCA countries' total resources in this category

  12. Characterization of past and present solid waste streams from the Plutonium-Uranium Extraction Plant

    International Nuclear Information System (INIS)

    Pottmeyer, J.A.; Weyns, M.I.; Lorenzo, D.S.; Vejvoda, E.J.; Duncan, D.R.

    1993-04-01

    During the next two decades the transuranic wastes, now stored in the burial trenches and storage facilities at the Hanford Site, are to be retrieved, processed at the Waste Receiving and Processing Facility, and shipped to the Waste Isolation Pilot Plant near Carlsbad, New Mexico for final disposal. Over 7% of the transuranic waste to be retrieved for shipment to the Waste Isolation Pilot Plant has been generated at the Plutonium-Uranium Extraction (PUREX) Plant. The purpose of this report is to characterize the radioactive solid wastes generated by PUREX using process knowledge, existing records, and oral history interviews. The PUREX Plant is currently operated by the Westinghouse Hanford Company for the US Department of Energy and is now in standby status while being prepared for permanent shutdown. The PUREX Plant is a collection of facilities that has been used primarily to separate plutonium for nuclear weapons from spent fuel that had been irradiated in the Hanford Site's defense reactors. Originally designed to reprocess aluminum-clad uranium fuel, the plant was modified to reprocess zirconium alloy clad fuel elements from the Hanford Site's N Reactor. PUREX has provided plutonium for research reactor development, safety programs, and defense. In addition, the PUREX was used to recover slightly enriched uranium for recycling into fuel for use in reactors that generate electricity and plutonium. Section 2.0 provides further details of the PUREX's physical plant and its operations. The PUREX Plant functions that generate solid waste are as follows: processing operations, laboratory analyses and supporting activities. The types and estimated quantities of waste resulting from these activities are discussed in detail

  13. The Influences of Percent of Tributyl Phosphate and Ratio of Feed and Solvent on the Uranium-Thorium Extraction of Thorex Process

    International Nuclear Information System (INIS)

    Setyadji, Moch; Endang Susiantini

    2002-01-01

    The investigation of uranium and thorium extraction in water phase of thorex process first cycle using tributyl phosphate diluted in kerosine as extractant has been done. The one stage extractor was used. The effects of percent of tributyl phosphate and ratio of feed and solvent on the extraction efficiency and distribution coefficients of uranium and thorium were studied. The result of experiment showed that percent of tributyl phosphate and ratio of feed and solvent very influence on the extraction efficiency and distribution coefficients of uranium and thorium. The best results were reached at about 55% of tributyl phosphate and ratio of feed and solvent was 1:3. The extraction efficiencies of uranium and thorium and distribution coefficients of uranium and thorium at the condition above were 90% , 90.4% , 9.0 and 9.4. (author)

  14. The Influenced of Salting Out Agent of Phosphat Ion and Ferrosulfamic in Extraction of Thorium and Uranium

    International Nuclear Information System (INIS)

    Busron Masduki; Didiek Herhady, R.

    2002-01-01

    It was carried out thorium-uranium extraction using one stage mixer settler to investigate the influenced of salting out agent of nitric acid and nitric aluminium. The result of this experiment showed the salting out of agent for nitric aluminium of 0.5 M much more significantly increase the distribution coefficient of uranium, but not for the thorium. The distribution coefficient of thorium much more significantly increased after nitric aluminium addition ≥1.0 M. There was not any meaningly differences the waste volume between nitric acid and nitric aluminium in its utilization. Reductor agent of ion Fe 2+ for chromi and decontaminate agent for protactinium in feed extraction, did not any influences of thorium and uranium distribution coefficient. (author)

  15. Development and inculcation of new methods in the field of exploring, extraction and reprocessing of uranium raw materials

    International Nuclear Information System (INIS)

    Smirnov, Yu.V.; Efimova, Z.I.; Skorovarov, D.I.; Ivanov, G.F.

    1979-01-01

    The situation is briefly overviewed in the field of exploration, prospecting, extraction and processing of uranium raw material and industrial introduction of the recently developed methods. The method of underground leaching, including that from deep-seated deposits, is gaining wide acceptance. Of high importance is the industrial introduction of such promising processes as bacterial leaching, continuous column-sorption with a pseudo-luquefied sorbent layer, direct production of UF 6 in an ore-processing factory. Active works are under way now in the field of multi-purpose utilization of uranium ore. New methods are industrially introduced for the extraction of associated uranium from phosphoric acid solutions, copper ore, sea water

  16. Efficient Functionalization of Polyethylene Fibers for the Uranium Extraction from Seawater through Atom Transfer Radical Polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Neti, Venkata S. [Chemical; Das, Sadananda [Chemical; Brown, Suree [Department; Janke, Christopher J. [Materials; Kuo, Li-Jung [Marine; Gill, Gary A. [Marine; Dai, Sheng [Chemical; Department; Mayes, Richard T. [Chemical

    2017-09-14

    Brush-on-brush structures are proposed as one method to overcome support effects in grafted polymers. Utilizing glycidyl methacrylate (GMA) grafted on polyethylene (PE) fibers using radiation-induced graft polymerization (RIGP) provides a hydrophilic surface on the hydrophobic PE. When integrated with atom transfer radical polymerization (ATRP), the grafting of acrylonitrile (AN) and hydroxyethyl acrylate (HEA) can be controlled and manipulated more easily than with RIGP. Poly(acrylonitrile)-co-poly(hydroxyethyl acrylate) chains were grown via ATRP on PE-GMA fibers to generate an adsorbent for the extraction of uranium from seawater. The prepared adsorbents in this study demonstrated promise (159.9 g- U/kg of adsorbent) in laboratory screening tests using a high uranium concentration brine and 1.24 g-U/Kg of adsorbent in the filtered natural seawater in 21-days. The modest capacity in 21- days exceeds previous efforts to generate brush-on-brush adsorbents by ATRP while manipulating the apparent surface hydrophilicity of the trunk material (PE).

  17. Radiological evaluation near three old mines of uranium extraction in the department of Creuse - year 2007

    International Nuclear Information System (INIS)

    2007-01-01

    The observations made for three sites of 'Chaumaillat, Ribiere and Grands Champs', demonstrate the existence of an atypical radiological situation which seems marked by the past activities of the mining. If the geochemical context can sometimes be at the origin of abnormalities in sediments and muds, the regional industrial context, conjugated to the strong measured values of uranium, incites us to privilege a human origin to explain these abnormalities. The presence of almost pure uraniums is the result supposed by the past activities of ore treatment on site (lixiviation) to extract the raw material from it (yellow cake) used for the manufacturing of the nuclear fuel. However, this observation on the site of 'Grands Champs' is surprising considering the absence of treatment activity in situ declared by the operator and the absence of residues storage.Given the accessibility of these sites to the public and considering the stop of any device of surveillance, a follow-up study seems necessary to estimate the importance of the radiological abnormalities and their persistent impact on the environment. (N.C.)

  18. Influence of Contact Time on the Extraction of 233Uranyl Spike and Contaminant Uranium From Hanford Sediment

    International Nuclear Information System (INIS)

    Smith, Steven C.; Szecsody, James E.

    2011-01-01

    In this study 233Uranyl nitrate was added to uranium (U) contaminated Hanford 300 Area sediment and incubated under moist conditions for 1 year. It hypothesized that geochemical transformations and/or physical processes will result in decreased extractability of 233U as the incubation period increases, and eventually the extraction behavior of the 233U spike will be congruent to contaminant U that has been associated with sediment for decades. Following 1 week, 1 month, and 1 year incubation periods, sediment extractions were performed using either batch or dynamic (sediment column flow) chemical extraction techniques. Overall, extraction of U from sediment using batch extraction was less complicated to conduct compared to dynamic extraction, but dynamic extraction could distinguish the range of U forms associated with sediment which are eluted at different times.

  19. Comparison of the performance of full scale pulsed columns vs. mixer-settlers for uranium solvent extraction

    International Nuclear Information System (INIS)

    Movsowitz, R.L.; Kleinberger, R.; Buchalter, E.M.; Grinbaum, B.

    2000-01-01

    A rare opportunity arose to compare the performance of Bateman Pulsed Columns (BPC) vs. Mixer-Settlers at an industrial site, over a long period, when the Uranium Solvent Extraction Plant of WMC at Olympic Dam, South Australia was upgraded. The original plant was operated for years with two trains of 2-stage mixer-settler batteries for the extraction of uranium. When the company decided to increase the yield of the plant, the existing two trains of mixer-settlers for uranium extraction were arranged in series, giving one 4-stage battery. In parallel, two Bateman Pulsed Columns, of the disc-and-doughnut type, were installed to compare the performance of both types of equipment over an extended period.The plant has been operating in parallel for three years and the results show that the performance of the columns is excellent: the extraction yield is similar to the 4 mixer-settlers in series - about 98%, the entrainment of solvent is lower, there are less mechanical failures, less problems with crud, smaller solvent losses and the operation is simpler. The results convinced WMC to install an additional 10 BPC's for the expansion of their uranium plant. These columns were successfully commissioned early 1999. This paper includes quantitative comparison of both types of equipment. (author)

  20. Safety and environmental aspect uranium mining and extraction in Kalan, Kalimantan

    International Nuclear Information System (INIS)

    Mudiar Masdja; Tampubolon, P.; Sihombing, W.

    1996-01-01

    Safety in uranium mining and extraction in Kalan, Kalimantan, Batan's activities, has been observed by concerning about personnel safety, monitoring of the work place and radiation surveillance. the personnel safety includes procurements of personnel protective equipment, work clothes, and washing facility. monitoring of the work place covers climate (temperature, humidity) noise frequency, poisonous gases, and tailing management. Radiation surveillance measures Rn gas and radioactive dust . Environmental assessment of Kalan site consist of physical, biological and cultural environments. The physical assessment mayor area such as water and air qualities, morphology and climatology. the biological assessment examines flora, fauna and aquatic biota. The culture assessment collect data of human population and distribution, occupation and income level, education, health and public perception. Guidelines for environmental management and monitoring have been documented and they have in Kalan site. (author). 8 refs; 3 tabs; 3 figs

  1. Simultaneous spectrophotometric determination of uranium and zirconium using cloud point extraction and multivariate methods

    International Nuclear Information System (INIS)

    Ghasemi, Jahan B.; Hashemi, Beshare; Shamsipur, Mojtaba

    2012-01-01

    A cloud point extraction (CPE) process using the nonionic surfactant Triton X-114 to simultaneous extraction and spectrophotometric determination of uranium and zirconium from aqueous solution using partial least squares (PLS) regression is investigated. The method is based on the complexation reaction of these cations with Alizarin Red S (ARS) and subsequent micelle-mediated extraction of products. The chemical parameters affecting the separation phase and detection process were studied and optimized. Under the optimum experimental conditions (i.e. pH 5.2, Triton X-114 = 0.20%, equilibrium time 10 min and cloud point 45 C), calibration graphs were linear in the range of 0.01-3 mg L -1 with detection limits of 2.0 and 0.80 μg L -1 for U and Zr, respectively. The experimental calibration set was composed of 16 sample solutions using an orthogonal design for two component mixtures. The root mean square error of predictions (RMSEPs) for U and Zr were 0.0907 and 0.1117, respectively. The interference effect of some anions and cations was also tested. The method was applied to the simultaneous determination of U and Zr in water samples.

  2. Contribution to the study of liquid-liquid extraction dynamics in the case of fast transfers. Extractions of uranium, plutonium and neptunium in a laboratory centrifugal extractor

    International Nuclear Information System (INIS)

    Bergeonneau, Philippe

    1978-01-01

    The liquid-liquid extraction (also named solvent-based extraction) is a very important technique for the reprocessing of irradiated nuclear fuels. This research thesis is based on the use of a laboratory centrifugal extractor which allows interesting conditions to be achieved: fast transfer due to an intense solution mixing, very short duration of contact between solutions. Thus, after a report of a bibliographical study on chemical mechanisms of extraction, on the composition of extracted species, on extraction kinetics, and on centrifugal extractors, this thesis reports the design, fabrication and use of a centrifugal extractor: presentation of fundamental principles, description and characteristics (materials, hydrodynamic operation test and problems, prototype). It reports studies of fast transfer kinetics: mathematical processing, result interpretation, results and discussions of extraction kinetics for nitric acid, uranium VI and IV, plutonium IV, neptunium IV, and comparison of the different extraction kinetics

  3. Mathematical Modeling for the Extraction of Uranium and Molybdenum with Emulsion Liquid Membrane, Including Industrial Application and Cost Evaluation of the Uranium Recovery

    International Nuclear Information System (INIS)

    Kris Tri Basuki

    2008-01-01

    Emulsion liquid membrane systems are double emulsion drops. Two immiscible phases are separated by a third phase which is immiscible with the other two phases. The liquid membrane systems were classified into two types: (1) carrier mediated mass transfer, (2) mass transfer without any reaction involved. Uranium extraction, molybdenum extraction and solvent extraction were used as purposed elements for each type of the membrane systems in the derivation of their mathematical models. Mass transfer in emulsion liquid membrane (ELM) systems has been modeled by several differential and algebraic equations. The models take into account the following : mass transfer of the solute from the bulk external phase to the external phase-membrane interface; an equilibrium reaction between the solute and the carrier to form the solute-carrier complex at the interface; mass transfer by diffusion of the solute-carrier complex in the membrane phase to the membrane-internal phase interface; another equilibrium reaction of the solute-carrier complex to release the solute at the membrane-internal phase interface into the internal phase. Models with or without the consideration of film resistances were developed and compared. The models developed in this study can predict the extraction rate through emulsion liquid membranes theoretically. All parameters required in the models can be determined before an experimental extraction run. Experimental data from literature (uranium extraction) and (molybdenum extraction and solvent extraction) were used to test the models. The agreements between the theoretical predictions and the experimental data were very good. The advantages of emulsion liquid membrane systems over traditional methods were discussed. The models developed in this research can be used directly for the design of emulsion liquid membrane systems. The results of this study represent a very significant step toward the practical applications of the emulsion liquid membrane

  4. Study of uranium(VI) speciation in phosphoric acid solutions and of its recovery by solvent extraction

    International Nuclear Information System (INIS)

    Dartiguelongue, Adrien

    2014-01-01

    Because small amounts of uranium are present in phosphate rocks, wet phosphoric acids may contain up to 300 ppm of uranium(VI). Therefore, such acids are a cost-effective unconventional source of this metal. Its recovery is a challenge for metallurgical firms which must develop reliable and selective solvent extraction processes. Such processes need to know the chemical equilibria involved in the extraction process, the speciation of uranium and its thermodynamics in solution. These two last points have been investigated in this work. Firstly, the most probable species of uranium(VI) in phosphoric acid solutions have been selected thanks to a detailed review of the literature. Then, a thermodynamic model founded on an equation of state for electrolytes has been built according these hypotheses. It has been validated with speciation data coming from original ATR-IR spectroscopy measurements. Finally, the composition of the aqueous phosphoric acid solutions and the activity coefficients obtained have been combined with a chemical model of uranium(VI) extraction into an organic phase containing a synergistic mixture of bis(2-ethylhexyl)phosphoric acid (D2EHPA) and tri-n-octylphosphine oxide (TOPO) in order to represent the variation of the distribution coefficient of uranium(VI) with H 3 PO 4 concentration. This model had been previously developed at Chimie ParisTech at a given concentration of H 3 PO 4 (i.e., 5,3 mol/L), but in the present study we have tested its validity in an extended range of phosphoric acid concentrations (i.e., 1-7 mol/L) and improved it. (author)

  5. Application of alkaline leaching to the extraction of uranium from shale of the Vosges

    International Nuclear Information System (INIS)

    Mouret, P.; Pottier, P.; Le Bris, J.

    1958-01-01

    Description of chemical treatment of Vosges shales to obtain uranium by alkaline leaching. Mineralogy aspects of ore, physical and chemical conditions of leaching, solid/liquid separation, uranium recovery by either ion exchange process or electrolytic precipitation. (author) [fr

  6. The uranium waste fluid processing examination by liquid and liquid extraction method using the emulsion flow method

    International Nuclear Information System (INIS)

    Kanda, Nobuhiro; Daiten, Masaki; Endo, Yuji; Yoshida, Hideaki; Mita, Yutaka; Naganawa, Hirochika; Nagano, Tetsushi; Yanase, Nobuyuki

    2015-03-01

    Spent centrifuges which had used for the development of the uranium enrichment technology are stored in the uranium enrichment facility located in Ningyo-toge Environmental Center, Japan Atomic Energy Agency (JAEA). Our technology of the centrifugal machine processing are supposed to separate the radioactive material adhered on surface of inner parts of centrifuges by the wet way decontamination method using the ultrasonic bath filled dilute sulfuric acid and water, and it is generated the neutralization sediment (sludge) by the processing of the radioactive waste fluid with the decontamination. JAEA had been considering the applicability of a streamlining and reduction of the processing of the sludge by decreases radioactive concentration including the sludge through the removes uranium from the radioactive waste fluid. As part of considerations, JAEA have been promoting technological developments of the uranium extraction separation using The Emulsion Flow Extraction Method (a theory propounded by JAEA-Nuclear Science and Engineering Center) in close coordination and cooperation between with JAEA-Nuclear Science and Engineering Center and Ningyo-toge Environmental Center from 2007 fiscal year. This report describes the outline of the application test using actual waste fluid of dilute sulfuric acid and water by developed the examination system introducing the emulsion flow extraction method. (author)

  7. Preconcentration of trace uranium from seawater with solid phase extraction followed by differential pulse polarographic determination in chloroform eluate

    International Nuclear Information System (INIS)

    Dojozan, Dj.; Pournaghi-Azar, M.H.; Toutounchi-Asr, J.

    1998-01-01

    In the present study, an effective method is presented for the separation and preconcentration of uranium (VI) by solid phase extraction (SPE). For this purpose, U(VI) oxinate is formed by the reaction of U(VI) with 8-hydroxyquinoline and adsorbed onto the octylsilane (C-8) SPE cartridge. The analyte is completely eluted with chloroform and determined by differential pulse polarography. The SPE conditions were optimized by evaluating the effective factors such as pH, oxine concentration, type and concentration of buffer and masking agent. By the proposed method a preconcentration factor of more than 100 was achieved. The average recovery of uranium (VI) oxinate (0.1 mg l -1 ) was 99.8%. The relative standard deviation was 1.6% for seven replicate determinations of uranyl ion in the solution with a concentration 20 μg l -1 . Some concomitant ions such as Ca +2 , Mg +2 and Fe +3 which interfere in extraction or determination process of uranium were masked with EDTA in aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in Caspian Sea and Persian Gulf water samples

  8. A study of the direct spectrophotometric determination of uranium (VI) in trialkylamine extracts with 2-(5-bromo- 2-pyridylazo)-5-diethylaminophenol

    International Nuclear Information System (INIS)

    Lyle, S.J.; Tamizi, M.

    1979-01-01

    A straightforward spectrophotometric method is described for the determination of uranium (VI) in trialkylamine sulphate extracts in kerosene diluent; 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) is used for colour formation without resort to back extraction into an aqueous phase. The method provides good tolerance to sulphate ion and rapid colour development and appears to be free from interference when applied to extracts from uranium sulphate leach liquors. (Auth.)

  9. Spectrophotometric Determination of Microamounts of Uranium previous Extraction with TBP-MIC; Determinacion Espectrofotometrica de Microcantidades de Uranio previa extraccin con Metilisobutilcetona-Fosfato de Tributilo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement, J; Fernandez Cellini, R

    1962-07-01

    Selective extraction of uranium in nitric acid medium with a mixture of Tbp-MIC (1:10) has been achieved. Aluminium nitrate was used as salting agent. Complexing agents were added in order to avoid extraction of impurities. Extraction conditions have been studied so that extraction is almost practically complete in a single run. (Author) 19 refs.

  10. Solvent extraction of uranium(VI) and thorium(IV) from nitrate media by carboxylic acid amides

    International Nuclear Information System (INIS)

    Preston, J.S.; Preez, A.C. du

    1995-01-01

    A series of nineteen N-alkyl carboxylic acid amides (R.CO.NHR') has been prepared, in which the alkyl groups R and R' have been varied in order to introduce different degrees of steric complexity into the compounds. A smaller number of N,N-dialkyl amides (R.CO.NR 2 ') and non-substituted amides (R.CO.NH 2 ) has also been prepared for comparison purposes. These amides were characterized by measurement of their boiling points, melting points, refractive indices and densities. The solvent extraction of uranium(VI) and thorium(IV) from sodium nitrate media by solutions of the amides in toluene was studied. Increasing steric bulk of the alkyl groups R and R' was found to cause a marked decrease in the extraction of thorium, with a much smaller effect on the extraction of uranium, thus considerably enhancing the separation between these metals. Vapour pressure osmometry studies indicate that the N-alkyl amides are self-associated in toluene solution, with aggregation numbers up to about 2.5 for 0.6 M solutions at 35 degree C. In contrast, the N,N-dialkyl amides behave as monomers under these conditions. The distribution ratios for the extraction of uranium and thorium show second- and third-order dependences, respectively, on the extractant concentration for both the N-alkyl and N,N-dialkyl amides. 15 refs., 8 figs., 8 tabs

  11. Uranium extraction from phosphates: Background, opportunities, process overview and way forward for commercialisation

    International Nuclear Information System (INIS)

    Haldar, T.K.; Hilton, J.; Tulsidas, H.

    2014-01-01

    Socio-economic up-gradation for major part of global population, particularly in developing countries will call for large growth of electricity demand. The fact that 2 billion of world’s 7 billion population do not have access to electricity justifies this growth projection. Environmental concern along with increasing demand for other essential ingredients for improved standard of living like affordable food, water, healthcare etc. will encourage large growth in nuclear technology utilisation. While conventional uranium resources will continue to be the major source for meeting the resultant surge in uranium demand, there is a need to look forward beyond this. Inherent advantage of uranium extraction from phosphate (UxP) is that it is the by-product of phosphate fertilizer industry. There is no need for separate mine development, ore processing or tailing disposal. Feed phosphoric acid is available from phosphate industry in ready to use condition. UxP thus enables recovery of energy resource otherwise lost for ever besides making the fertiliser cleaner. UxP has also potential to make phosphate industry economically more viable and socially more acceptable. Phosphate industry also benefits from cleaner return acid making operation of downstream plant simpler and cleaner besides possible value addition of the product basket Due to low uranium concentration in source material, normally in the range of 80 – 150 ppm, and several process and engineering issues inherent to this relatively difficult separation process, large scale commercial deployment will depend on development of commercially viable technology. Though the process has been utilised for production of uranium in the past, before setting up a new commercial facility, it is imperative that its techno-economic feasibility be established considering all related aspects of the proposed facility. This will address the difficulties encountered in earlier plants, problems related to wide variation in physical

  12. Leaching study of heavy and radioactive elements present in wastes discarded by a uranium extraction and processing facility

    International Nuclear Information System (INIS)

    Pihlak, A.; Lippmaa, E.; Maremaee, E.; Sirk, A; Uustalu, E.

    1995-08-01

    The present report provides a systematic leaching study of the waste depository at the Sillamaee metallurgical plant 'Silmet' (former uranium extraction and processing facility), its construction and environmental impact. The following data are presented: γ-activity data of the depository and two drill cores, chemical composition and physical properties of depository material and leaching waters, results of γ- and α-spectrometric studies, leaching (with demineralized and sea water) intensities of loparite and uranium ore processing waste components. Environmental danger presented by the Sillamaee waste dump to the Gulf of Finland and the surrounding environment in Estonia is mainly due to uranium leaching and the presence of a large array of chemically poisonous substances

  13. Extraction of Uranium in The Mixtures of Nitric and Sulfuric Acids With Neutral and Basic Ligands in Kerosene

    International Nuclear Information System (INIS)

    Nampira, Y; Rahayu Imam, S; Djoyosubroto, H

    1998-01-01

    The tendency of uranium ion in the mixture of nitric and sulfuric acid's medium is to from uranyl sulphate complex. The compound of uranyl sulphate is containing into the heteropoly compound that has acid property. Regarding to the mentioned property, the U extraction process was carried out using a basic or neutral complexing agent containing a ligand that formed the soluble uranium complex in the organic solvent (kerosene).The use of basic complexing agent such as n,tri-octyl amine is more suitable than that of tri butyl phosphate as a neutral agent. The maximum distribution coefficient of uranium will be reached if the maximum concentration of nitric acid and sulphuric acid can be maintained at 0.3 M and 1.5 M respectively in the organic solvent medium consisted n,tri-octyl amine of 30% volume fraction

  14. Comparison and analysis of the existing methods of the uranium and its compounds extraction from the materials of the nuclear power

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Azarenkov, N.A.; Borts, B.V.; Odejchuk, N.P.; Skoromnaya, S.F.; Tkachenko, V.I.

    2008-01-01

    The brief review of the existing methods of the uranium isotope separation as well as for natural uranium enrichment, as for regeneration of the spent nuclear fuel, and also the description of a new intensively developed separation method is given last time - the supercritical fluid extraction in the carbonic acid medium is shown. The comparison of the basic technological indicators of the uranium enrichment by the traditional methods in the supercritical carbonic acid medium is shown. 27 refs.; 18 figs.; 16 tab

  15. Separation of uranium(VI) by liquid-solid extraction with tri-n-octylphosphine oxide diluted with naphthalene

    International Nuclear Information System (INIS)

    Shigetomi, Y.; Kojima, T.; Kamba, H.; Yamamoto, Y.

    1980-01-01

    Liquid-liquid distribution with tri-n-octylphosphine oxide (TOPO) and molten naphthalene has been investigated for the extraction of 20 metals from nitric acid and hydrochloric acid solutions. Uranium is quantitatively extracted from 1 M nitric acid or hydrochloric acid by using 100 mg of TOPO and 200 mg of naphthalene and shaking for 5 min at 80 0 C, and separated from transition metals, alkaline earth metals and rare earth metals (except scandium). Addition of naphthalene increases the extraction efficiency. (Auth.)

  16. Solvent. I. Extraction systems applied to uranium analysis. I. Extraction studies with Tributyl phosphate-Methyl-isobutyl-ketone; Metodos de extraccion don disolventes aplicados al analisis quimico del uranio. I. Estudio de la extraccion con fosfato de tributilo-metilisobutilcetano

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement Eguiluz, J C

    1964-07-01

    A factorial study of the selective extraction of uranium with a mixture of TBP-MIC was carried out using 0,8 N nitric acid and different salting agents. We use the most suitable salting agent to develop new factorial experiments in order to get an equation involving the percent of extracted uranium, E, the concentration of the extraction agent in the organic phase, c, and the concentration of the slating agent in the aqueous phase, n. (Author) 3 refs.

  17. Detection of carbon dioxide in the gases evolved during the hot extraction determination of hydrogen in uranium ingots

    International Nuclear Information System (INIS)

    Jursik, M.L.; Pope, J.D.

    1977-08-01

    The hot extraction method was used at the National Lead Company of Ohio to determine hydrogen in uranium metal at the 2 ppM level. The volume of gas evolved from the heated sample was assumed to be hydrogen. When a liquid nitrogen trap was placed into the system the hydrogen values were reduced 5 to 10%. The gas retained by the nitrogen trap was identified by mass spectrometry as predominantly carbon dioxide. Low hydrogen values were observed only when the nitrogen trap was used in the analysis of high-carbon (300 to 600 ppM) uranium from NLO production ingots. However, hydrogen values for low-carbon (30 to 50 ppM) uranium were unaffected by the nitrogen trap. The formation of carbon dioxide appears to be associated with the carbon content of the uranium metal. Comparisons of hydrogen values obtained with the hot extraction method and with an inert fusion--thermal conductivity method are also presented. 3 tables, 4 figures

  18. Simple and Rapid Dual-Dispersive Liquid-Liquid Microextraction as an Innovative Extraction Method for Uranium in Real Water Samples Prior to the Determination of Uranium by a Spectrophotometric Technique.

    Science.gov (United States)

    Khan, Naeemullah; Tuzen, Mustafa; Kazi, Tasneem Gul

    2017-11-01

    An innovative, rapid, and simple dual-dispersive liquid-liquid microextraction (DDLL-ME) approach was used to extract uranium from real samples for the first time. The main objective of this study was to disperse extraction solvent by using an air-agitated syringe system to overcome matrix effects and avoid dispersion of hazardous dispersive organic solvents by using heat. The DDLL-ME method consisted of two dispersive liquid-liquid extraction steps with chloroform as the extracting solvent. Uranium formed complexes with 4-(2-thiazolylazo) resorcinol in the aqueous phase and was extracted in extracting solvent (chloroform) after the first dispersive liquid-liquid process. Uranium was then back-extracted in the acidic aqueous phase in a second dispersive liquid-liquid process. Finally, uranium was determined by a spectrophotometric detection technique. The variables that played a key role in the proposed method were studied and optimized. The LOD and sensitivity enhancement factor for uranium were found to be 0.60 µg/L and 45, respectively, under optimized conditions. Calibration graphs were found to be linear in the range of 5.0-600 µg/L. The RSD was 2.5%. Reliability of the proposed method was verified by analyzing certified reference material TM-28.3.

  19. Czechoslovak uranium

    International Nuclear Information System (INIS)

    Pluskal, O.

    1992-01-01

    Data and knowledge related to the prospecting, mining, processing and export of uranium ores in Czechoslovakia are presented. In the years between 1945 and January 1, 1991, 98,461.1 t of uranium were extracted. In the period 1965-1990 the uranium industry was subsidized from the state budget to a total of 38.5 billion CSK. The subsidies were put into extraction, investments and geologic prospecting; the latter was at first, ie. till 1960 financed by the former USSR, later on the two parties shared costs on a 1:1 basis. Since 1981 the prospecting has been entirely financed from the Czechoslovak state budget. On Czechoslovak territory uranium has been extracted from deposits which may be classified as vein-type deposits, deposits in uranium-bearing sandstones and deposits connected with weathering processes. The future of mining, however, is almost exclusively being connected with deposits in uranium-bearing sandstones. A brief description and characteristic is given of all uranium deposits on Czechoslovak territory, and the organization of uranium mining in Czechoslovakia is described as is the approach used in the world to evaluate uranium deposits; uranium prices and actual resources are also given. (Z.S.) 3 figs

  20. Functional design criteria for the 242-A evaporator and PUREX [Plutonium-Uranium Extraction] Plant condensate interim retention basin

    International Nuclear Information System (INIS)

    Cejka, C.C.

    1990-01-01

    This document contains the functional design criteria for a 26- million-gallon retention basin and 10 million gallons of temporary storage tanks. The basin and tanks will be used to store 242-A Evaporator process condensate, the Plutonium-Uranium Extraction (PUREX) Plant process distillate discharge stream, and the PUREX Plant ammonia scrubber distillate stream. Completion of the project will allow both the 242-A Evaporator and the PUREX Plant to restart. 4 refs

  1. Antagonism in the extraction of uranium(VI) by the binary mixture of PC88A and benzimidazole

    International Nuclear Information System (INIS)

    Mukherjee, A.; Kamila, S.; Chakravortty, V.

    1999-01-01

    Extraction studies of uranium(VI) by the binary mixture of PC88A and benzimidazole show an antagonistic behavior in the concentration range 10 -5 -10 -6 M of PC88A and 0.005M of benzimidazole. Antagonism is observed due to the deprotonation of PC88A by benzimidazole forming an adduct resulting in the virtual removal of PC88A from the system. (author)

  2. Surveillance and Maintenance Plan for the Plutonium Uranium Extraction (PUREX) Facility

    International Nuclear Information System (INIS)

    Woods, P.J.

    1998-05-01

    This document provides a plan for implementing surveillance and maintenance (S ampersand M) activities to ensure the Plutonium Uranium Extraction (PUREX) Facility is maintained in a safe, environmentally secure, and cost-effective manner until subsequent closure during the final disposition phase of decommissioning. This plan has been prepared in accordance with the guidelines provided in the U.S. Department of Energy (DOE), Office of Environmental Management (EM) Decommissioning Resource Manual (DOE/EM-0246) (DOE 1995), and Section 8.6 of TPA change form P-08-97-01 to the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) (Ecology, et al. 1996). Specific objectives of the S ampersand M program are: Ensure adequate containment of remaining radioactive and hazardous material. Provide security control for access into the facility and physical safety to surveillance personnel. Maintain the facility in a manner that will minimize potential hazards to the public, the environment, and surveillance personnel. Provide a plan for the identification and compliance with applicable environmental, safety, health, safeguards, and security requirements

  3. Method for determining microamounts of uranium in solutions from copper ores, by liquid-liquid extraction and spectrophotometry with arsenazo III

    International Nuclear Information System (INIS)

    Rodriguez, B.

    1972-01-01

    A spectrophotometric method is described for determining small amounts of uranium in aqueous solutions from copper ores. Uranium is quantitatively separated in a single extraction by a solution of tri-n-octylphosphine oxide in benzene, using ethylendiaminetetracetic acid and sodium fluoride as complexing agents, for improving the selectivity of the procedure. An aliquot of the extract is diluted with a hydrocolloidal solution of arsenazo III. Optical density is measured at 650 nm. (Author) 3 refs

  4. Determination of trace uranium by resonance fluorescence method coupled with photo-catalytic technology and dual cloud point extraction.

    Science.gov (United States)

    Li, Jiekang; Li, Guirong; Han, Qian

    2016-12-05

    In this paper, two kinds of salophens (Sal) with different solubilities, Sal1 and Sal2, have been respectively synthesized, and they all can combine with uranyl to form stable complexes: [UO2(2+)-Sal1] and [UO2(2+)-Sal2]. Among them, [UO2(2+)-Sal1] was used as ligand to extract uranium in complex samples by dual cloud point extraction (dCPE), and [UO2(2+)-Sal2] was used as catalyst for the determination of uranium by photocatalytic resonance fluorescence (RF) method. The photocatalytic characteristic of [UO2(2+)-Sal2] on the oxidized pyronine Y (PRY) by potassium bromate which leads to the decrease of RF intensity of PRY were studied. The reduced value of RF intensity of reaction system (ΔF) is in proportional to the concentration of uranium (c), and a novel photo-catalytic RF method was developed for the determination of trace uranium (VI) after dCPE. The combination of photo-catalytic RF techniques and dCPE procedure endows the presented methods with enhanced sensitivity and selectivity. Under optimal conditions, the linear calibration curves range for 0.067 to 6.57ngmL(-1), the linear regression equation was ΔF=438.0 c (ngmL(-1))+175.6 with the correlation coefficient r=0.9981. The limit of detection was 0.066ngmL(-1). The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-103.5%. The mechanisms of the indicator reaction and dCPE are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. The immiscible aqueous solutions of alkyl phosphates. Study for the purpose of uranium extraction from phosphoric acid solutions

    International Nuclear Information System (INIS)

    Mauborgne, Bernard

    1979-01-01

    Systems of immiscible aqueous solutions composed by a phase rich in mineral salt and by another phase almost totally containing an organic salt, have been studied for years, with quaternary ammonium salts with an organic cation. The objective of this research is to study systems symmetric to the previous ones, i.e. with organic anions such as alkyl phosphates, and then to try to understand mechanisms of extraction of metals in these environments. Based on properties of immiscible aqueous solutions, an original three-phase process of liquid-liquid extraction has been developed, and is used to separate uranium in phosphoric acids with better performance than the existing industrial processes [fr

  6. Behaviour analysis of uranium purification pilot plant taking into consideration the incorporation of a second column of extraction in the process flow chart

    International Nuclear Information System (INIS)

    Souza Barbosa, E.M. de.

    1979-01-01

    This work analyses the effect of the incorporation of a second column of extraction by solvents in pulsed plate columns in the Process of Uranium Purification. Operating with the aqueous phase of washing this second column of extraction recovers the dragged Uranium, increasing the efficiency of the process. The experiments were carried out in the display unit of Uranium purification in the Institute of Energetic and Nuclear Researches in Sao Paulo, where the dimension and the performance were studied with the following parameters: real increase in the efficiency and decontamination in the process. An efficiency superior to 98% in mass was obtained against 84,6% in the conventional process. With a performance similar to the first column of extract on the decontamination, about 99%, obtained in this column, maintained the grade of nuclear purity peculiar to the Process of Uranium Purification by solvents in pulsed plate columns. (author) [pt

  7. Development of a Kelp-Type Structure Module in a Coastal Ocean Model to Assess the Hydrodynamic Impact of Seawater Uranium Extraction Technology

    Directory of Open Access Journals (Sweden)

    Taiping Wang

    2014-02-01

    Full Text Available With the rapid growth of global energy demand, interest in extracting uranium from seawater for nuclear energy has been renewed. While extracting seawater uranium is not yet commercially viable, it serves as a “backstop” to the conventional uranium resources and provides an essentially unlimited supply of uranium resource. With recent technology advances, extracting uranium from seawater could be economically feasible only when the extraction devices are deployed at a large scale (e.g., several hundred km2. There is concern however that the large scale deployment of adsorbent farms could result in potential impacts to the hydrodynamic flow field in an oceanic setting. In this study, a kelp-type structure module based on the classic momentum sink approach was incorporated into a coastal ocean model to simulate the blockage effect of a farm of passive uranium extraction devices on the flow field. The module was quantitatively validated against laboratory flume experiments for both velocity and turbulence profiles.Model results suggest that the reduction in ambient currents could range from 4% to 10% using adsorbent farm dimensions and mooring densities previously described in the literature and with typical drag coefficients.

  8. Influence of diffusion on extraction kinetics in porous bodies. The case of uranium oxides; Influence de la diffusion sur la cinetique d'extraction dans un corps poreux. Cas des oxydes de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Tinturier, B [Commissariat a l' Energie Atomique, Fontenay-Aux-Roses (France). Centre d' Etudes Nucleaires

    1966-12-01

    The study of the leaching of heaped uranium ore can be considered theoretically as the problem of the diffusion of liquids in porous bodies and in particular as that of its influence on the chemical reaction rates of conventional uranium oxides. Below a certain value of the pore diameter, it is diffusion which is responsible for mass transfer. The porous structure can be characterized by various physical constants which modify the free diffusion equation and, as long as the pores have a diameter greater than a few microns, it can be shown that the pore walls have a negligible effect on the diffusion. The diffusion coefficients for the nitrate, the sulfate, the chloride, the acetate and the perchlorate of uranium have been determined. In the case of the reaction of uranium trioxide with acids in a porous body, the reaction kinetics are governed by the arrival of the reagent by diffusion. The attack of uranium dioxide by an acid ferric iron solution has been studied under the same conditions and it has been found that the diffusion modifies the influence of the ferrous and ferric iron concentrations on the reaction kinetics. The same is true for the oxide U{sub 3}O{sub 8}. All the results concerning these reactions studied in the absence of the influence of diffusion should be modified to take this factor into account when it intervenes in an extraction process. (authors) [French] L'etude de la lixiviation en tas d'un minerai d'uranium peut se ramener theoriquement au probleme de la diffusion des liquides dans les corps poreux et en particulier a celui de son influence sur les vitesses de reaction chimique des oxydes classiques de l'uranium. En dessous d'une certaine limite de diametre des pores la diffusion est responsable du transfert de masse. La structure poreuse peut se caracteriser par differentes constantes physiques qui modifient l'equation de la diffusion libre et tant que les pores ont un diametre superieur a quelques microns, on a montre que l

  9. Solvent-extraction methods applied to the chemical analysis of uranium. III. Study of the extraction with inert solvents; Metodos de extraccion con disolventes aplicados al analisis quimico del uranio. III. Estudio de la extraccion con disolvente inertes

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement Eguiluz, J C

    1964-07-01

    The extraction of uranium on the trace level is studied by using tributylphosphate as active agent under conditions aiming the attainment of quantitative extraction by means of a single step process using a number of salting-out agents and keeping inside the general lines as reported in two precedent papers. Two inert solvents were investigated, benzene and cyclohexane, which allowed to derive the corresponding empirical equations describing the extraction process and the results obtained were compared with those previously reported for solvents which, like ethyl acetate and methylisobuthylketone, favour to a more or less extend the extraction of uranium. (Author) 4 refs.

  10. Synthesis of a chelate resin with amido and phosphoric acid and its character in uranium extraction

    International Nuclear Information System (INIS)

    Qiu Yueshuang; Zhang Jianguo; Feng Yu; Zhao Chaoya

    2013-01-01

    A chelate resin (D814) with amido and phosphoric acid functional group was synthetized by means of the reactions of stytene-divinyl benzene chloromethylated sphere with ethylenedianmine and orth-phosphorous acid and formaldehyde. This resin can be used to adsorb uranium from leaching solution with high chloride ion in the rang of pH l.33-9.05, and the adsorption rate of uranium was above 95%. D814 resin had a good ability resistant to high chloride ion. The loading capacity for uranium was not apparently effected when chlorid ion concentration in solution was 60 g/L. The results of the adsorption experiment show that when the ratio of saturation volume to breakthrough volume was l.82, the uranium saturation capacity of D814 was 40.5 mg/g dry resin. NaCl + NaHCO 3 was used for eluting agent, and the eluting rate of uranium was 96.7%. Adsorption uranium mechanism by D814 was also discussed. (authors)

  11. Extraction of uranium from anomaly ores no 1,6,8 in salt domes of Bandar Abbas region using column leaching by seawater in sulfuric acid medium

    International Nuclear Information System (INIS)

    Fatemi, K.

    2003-01-01

    Column leaching is one of the experimental methods which is used for identifying the specifications of uranium ores. From the efficiency point of view, the process has some complications and usually it is applied in parallel with the conventional leaching process in order to facilitate of finding an appropriate design and operational method, to be applicable in an large practical scale. In this research work, at the first stage, the existed free chlorine in the samples was washed out using seawater. Then, in a process of acid leaching with seawater and sulfuric acid by the use of the column leaching was applied. The results show that the maximum of 85% of uranium from the ore of Anomali ≠1 is extracted. The extra residual of the used acid dose not react with the uranium and therefore it will increase the free acidity of the leach liquor. In Anomali ≠6, the extraction efficiency of uranium is 75%, while in Anomali ≠8, using 30 periods of leaching, the efficiency is 81%. However, the maximum efficiency achievement has to be avoided by the non-economical circumstances. Based on some comparisons, it is shown that the presence of chlorine in ore will affect the efficiency. The capability of s eawater i n uranium extraction from salted, compared with the n ormal or sweat water h as some advantages. These include: reduction of the operational period, less acid consumption, and reduction in the ore leaching costs. Thus, the heap leaching industry is believed to be a valuable and economical method for uranium extraction, where the needs of utilizing the complicated technical facilities can be reduced. The present work is the first research project on the uranium extraction and concentration in solution containing chlorine. Our experimental results can provide a valuable pattern for the heap leaching of uranium ores design from arches shaped in the region Bandar Abbas

  12. Irradiated uranium reprocessing

    International Nuclear Information System (INIS)

    Gal, I.

    1961-12-01

    Task concerned with reprocessing of irradiated uranium covered the following activities: implementing the method and constructing the cell for uranium dissolving; implementing the procedure for extraction of uranium, plutonium and fission products from radioactive uranium solutions; studying the possibilities for using inorganic ion exchangers and adsorbers for separation of U, Pu and fission products

  13. Extraction of bivalent vanadium as its pyridine thiocyanate complex and separation from uranium, titanium, chromium and aluminium

    International Nuclear Information System (INIS)

    Yatirajam, V.; Arya, S.P.

    1975-01-01

    A simple method is described for the extraction of V(II) as its pyridine thiocyanate complex. Vanadate is reduced to V(II) in 1 to 2 N sulphuric acid by zinc amalgam. Thiocyanate and pyridine are added, the solution is adjusted to pH 5.2 to 5.5 and the complex extracted with chloroform. The vanadium is back-extracted with peroxide solution. Zinc from the reductant accompanies the vanadium but alkali and alkaline earth metal ions, titanium, uranium, chromium and aluminium are separated, besides those ions reduced to the elements by zinc amalgam. The method takes about 20 min and is applicable to microgram as well as milligram amounts of vanadium. (author)

  14. Scale-up of the mixer of a mixer-settler model used in a uranium solvent extraction process

    International Nuclear Information System (INIS)

    Santana, A.O. de; Dantas, C.C.

    1995-01-01

    Scale-up relations were obtained for the mixer of a box type mixer-settler used in an uranium extraction process from chloridric leaches. Three box type mixers of different sizes and with the same geometry were used for batch and continuous-flow experiments. The correlations between the extraction rate and he specific power input, D/T ratio(=turbine diameter/mixer width) and residence time were experimentally determined. The results showed that the extraction rate increases with the power input at a constant D/T ratio equal to 1/3, remaining however, independent from the mixer size for a specific value of the power input. This behaviour was observed for power input values ranging from 100 to 750 W/m 3 . (author) 8 refs.; 8 figs.; 4 tabs

  15. Recovery of thorium and uranium from monazite processing Liquor produced by INB/Caldas, M G, by solvent extraction

    International Nuclear Information System (INIS)

    Amaral, Janubia Cristina Braganca da Silva

    2006-01-01

    This work describes the study of thorium and uranium recovery from sulfuric liquor generated in chemical monazite treatment by solvent extraction technique. The sulfuric liquor was produced by Industries Nuclear of Brazil - INB, Caldas - Minas Gerais State. The study was carried out in two steps: in the first the process variable were investigated through discontinuous experiments; in the second, the parameters were optimized by continuous solvent extraction experiments. The influence of the following process variables was investigated: type and concentration of extracting agents, contact time between phases and aqueous/organic volumetric ratio. Extractants used in this study included: Primene J M-T, Primene 81-R, Alamine 336 and Aliquat 336. Thorium and uranium were simultaneously extracted by a mixture of Primene J M-T and Alamine 336, into Exxsol D-100. The stripping was carried out by hydrochloric acid (HCl) 2.0 mol/L. The study was carried out at room temperature. After selected the best process conditions, two continuous experiments of extraction and stripping were carried out. In the first experiment a mixture of 0.15 mol/L Primene J M-T and 0.05 mol/L Alamine 336 were used. The second experiment was carried out using 0.15 mol/L Primene J M-T and 0.15 mol/L Alamine 336. Four extraction stages and five stripping stages were used in both experiments. The first experiment showed a ThU 2 and U 3 O 8 content in loaded strip solution of 34.3 g/L and 1.49 g/L respectively and 0.10 g/L Th) 2 and 0.05 g/L U 3 O 8 in the raffinate. In the second experiment a loaded strip solution with 29.3 g/L ThO 2 and 0.94 g/L U 3 O 8 was obtained. In this experiment, the metals content in raffinate was less than 0.001 g/L, indicating a thorium recovery over 99.9% and uranium recovery of 99.4%. (author)

  16. HTGR fuel development: loading of uranium on carboxylic acid cation-exchange resins using solvent extraction of nitrate

    International Nuclear Information System (INIS)

    Haas, P.A.

    1975-09-01

    The reference fuel kernel for recycle of 233 U to HTGR's (High-Temperature Gas-Cooled Reactors) is prepared by loading carboxylic acid cation-exchange resins with uranium and carbonizing at controlled conditions. The purified 233 UO 2 (NO 3 ) 2 solution from a fuel reprocessing plant contains excess HNO 3 (NO 3 - /U ratio of approximately 2.2). The reference flowsheet for a 233 U recycle fuel facility at Oak Ridge uses solvent extraction of nitrate by a 0.3 M secondary amine in a hydrocarbon diluent to prepare acid-deficient uranyl nitrate. This nitrate extraction, along with resin loading and amine regeneration steps, was demonstrated in 14 runs. No significant operating difficulties were encountered. The process is controlled via in-line pH measurements for the acid-deficient uranyl nitrate solutions. Information was developed on pH values for uranyl nitrate solution vs NO 3 - /U mole ratios, resin loading kinetics, resin drying requirements, and other resin loading process parameters. Calculations made to estimate the capacities of equipment that is geometrically safe with respect to control of nuclear criticality indicate 100 kg/day or more of uranium for single nitrate extraction lines with one continuous resin loading contactor or four batch loading contactors. (auth)

  17. Uranium extraction in northern Bohemia by leaching and provisions for remediation of its adverse impacts on the environment

    International Nuclear Information System (INIS)

    Tomas, J.

    1992-01-01

    The problems of uranium extraction at the Straz pod Ralskem and Hamr sites in northern Bohemia are highlighted. The geological situation at the two deposits is described. At Hamr, uranium is mined conventionally, whereas at Straz, hydrochemical extraction is practised. The two deposits are located close to each other, they affect one another and affect adversely the rock environment. A remedial programme has been worked out, based on (i) abandoning deep mining at the Hamr 1 mine and shutting down the ore treatment plant, (ii) preparation of a membrane project to decontaminate the Turonian groundwater body and ore processing lagoons, (iii) sustaining a protective hydraulic barrier between the Hamr 1 mine and the chemical extraction site, (iv) design preparation and construction of a desalination station, (v) monitoring the Turonian drinking water quality, and (vi) preparation of technologies for a final separation and use of alum and inert leachates. The technology of thermal concentration by evaporation followed by concentrate treatment was chosen for the decontamination of the polluted waters. The entire decontamination of the deposits is expected to take 50 to 70 years. (J.B.). 1 tab., 3 figs

  18. A review of uranium extraction from seawater: Recent international research and development

    International Nuclear Information System (INIS)

    Nor Azillah Fatimah Othman; Jamaliah Sharif; Siti Fatahiyah Mohamad

    2012-01-01

    Radiation-induced grafting co-polymerization is widely used technique to produce high performance chemically active polymer materials for adsorption and separation processes on the basis of various commercial polymers available in different forms (films, fibers, resins, textiles, powders). The design and synthesis of polymer supported reagents that can selectively complex metal ions from multi-component solutions have been an important area of research during the last decades. Uranyl ions have been one of the target ions to be removed from aqueous systems. Despite the very low uranium concentration (3.3 ppb) in seawater, its total amount reaches 4 x 10 12 kg, that is equivalent to 1000 times of the mine uranium. To recover an economically significant quantity of uranium from seawater, an adsorption method using a suitable solid adsorbent seems to be feasible with regard to economical and environmental impacts. Extensive investigations of adsorbents capable of recovering uranium from seawater and aqueous systems have been carried out during the last two decades especially in Japan Atomic Energy Agency, Japan but until now, this method is not feasible for mass production. In this paper, recent international activities are summarized, on both the laboratory scale experiments and large scale marine experiments. Research and Development opportunities are discussed for improving the system performance and making the collection of uranium from seawater more economically competitive. (author)

  19. Investigation of the synergic effect of some neutral organophosphoric compounds on the extraction of uranium from phosphoric acid solutions by D1-(2-Ethyl Hexyl) phosphoric acid

    International Nuclear Information System (INIS)

    Stas, J.; Khorfan, S.; Koudsi, Y.

    1998-05-01

    The extraction of uranium (VI) from pure phosphoric acid media by D2EHPA/Kerosene has been studied. The mechanism of the extraction was found as follows: The logarithm of the equilibrium constant of the extraction (LogKex) was found (3.06), (3.32), (3.24), (3.3) for the following phosphoric acid concentrations respectively (1), (2), (3), (4) Mol/1, and the enthalpy change DELTA H was found (-100.68 kj/mol). (-76 kj/mol) for (1), (2) mol/1 phosphoric acid concentrations. The synergic effect of TOPO, TBP, and TBPI with DEHPA have been studied during the extraction of uranium from pure phosphoric acid and Syrian commercial phosphoric acid. The synergic effect increases as follows: TBP< TBPI<< TOPO (In pure phosphoric acid), TBPI approx TBP<< TOPO (In Syrian commercial phosphoric acid). The difficulty of extracting uranium (VI) from Syrian commercial phosphoric acid in comparison with pure phosphoric acid is due to the presence of several impurities capable of complexing uranium, and a small amounts of solid and organic matters, all these are factors which reduce the distribution coefficient of uranium. (Author)

  20. Highly efficient extraction and selective separation of uranium (VI) from transition metals using new class of undiluted ionic liquids based on H-phosphonate anions.

    Science.gov (United States)

    Zarrougui, Ramzi; Mdimagh, Raouf; Raouafi, Nourreddine

    2018-01-15

    In this paper, we report the development of an environmental friendly process to decontaminate uranium-containing ores and nuclear wastes by using non-fluorinated ionic liquids (ILs). The main advantages of this extraction process are the absence of any organic diluent and extra extraction agents added to the organic phase. Moreover, the process is cost-effective and maybe applied as a sustainable hydrometallurgical method to recover uranium. The distribution ratio (D U ) and the extraction efficiency (%E) of uranium(VI) (UO 2 2+ ) were found to be dependent on the acidity of the aqueous phase, the extraction time, the alkyl chain length in the ILs, the concentration of the aqueous feed and molar quantity of ILs. The D U value is higher than 600 and the %E is equal to 98.6% when [HNO 3 ]=7M. The extraction reactions follows a neutral partition or ionic exchange mechanism depending on nitric acid concentration. The nature of bonding in the extracted complexes was investigated by spectroscopic techniques. The potential use of Mor 1-8 -OP for the separation of UO 2 2+ from a mixture containing transition metal ions M n+ was also examined. The UO 2 2+ ions were separated and extracted efficiently. These ILs are promising candidates for the recovery and separation of uranium. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. The effect of pore diameter in the arrangement of chelating species grafted onto silica surfaces with application to uranium extraction

    International Nuclear Information System (INIS)

    Charlot, A.; Cuer, F.; Grandjean, A.

    2017-01-01

    A series of five silica supports with different pore diameters were functionalized in two steps by post-grafting, producing three types of material: (1) initial supports with pores smaller than 4 nm are heterogeneously functionalized because of steric effects; (2) when the pores range from 5 to 20 nm in diameter, a homogeneous organic monolayer is grafted onto the silica skeleton; and (3) when the pores are larger than 30 nm, an organic multilayer covalently linked to the surface is obtained. These hybrid materials were then used to extract uranium from a sulphuric solution. Our results show that the efficiency, capacity and selectivity of the extraction can be controlled through the effect the initial pore size has on the organic structures that form therein. After regeneration moreover, these materials can be reused with the same efficiency. (authors)

  2. Stepwise hydrochloric acid extraction of monazite hydroxides for the recovery of cerium lean rare earths, cerium, uranium and thorium

    International Nuclear Information System (INIS)

    Swaminathan, T.V.; Nair, V.R.; John, C.V.

    1988-01-01

    Monazite sand is normally processed by the caustic soda route to produce mixed rare earth chloride, thorium hydroxide and trisodium phosphate. Bulk of the mixed rare earth chloride is used for the preparation of FC catalysts. Recently some of the catalyst producers have shown preference to cerium depleted (lanthanum enriched) rare earth chloride rather than the natural rare earth chloride obtained from monazite. Therefore, a process for producing cerium depleted rare earth chloride, cerium, thorium and uranium from rare earth + thorium hydroxide obtained by treating monazite, based on stepwise hydrochloric acid extraction, was developed in the authors laboratory. The process involves drying of the mixed rare earth-thorium hydroxide cake obtained by monazite-caustic soda process followed by stepwise extraction of the dried cake with hydrochloric acid under specified conditions

  3. Empirical equations of the solvent extraction of the energetic inputs, uranium and plutonium, calculated by using the program Microsoft Excel

    International Nuclear Information System (INIS)

    Bento, Dercio Lopes

    2006-01-01

    PUREX is one of the purification process for irradiated nuclear fuel. In the flowchart the program uses various uranium and plutonium extraction phases by using organic solvent contained in the aqueous phase obtained in the dissolution of the fuel element. A posterior extraction U and Pu are changed to the aqueous phase. So it is fundamental to know the distribution coefficient (dS), at the temperature (tc), of the substances among the two immiscible phases, for better calculation the suitable flowchart. A mathematical model was elaborated based on experimental data, for the calculation of the dS and applied to a referential band of substance concentrations in the aqueous phase (xS) and organic (yS). By using the program Excel, we personalized the empirical equations calculated by the root mean square. The relative deviation, among the calculated values and the experimental ones are the standards

  4. An extraction method of uranium 233 from the thorium irradiates in a reactor core

    International Nuclear Information System (INIS)

    Chesne, A.; Regnaut, P.

    1955-01-01

    Description of the conditions of separation of the thorium, of the uranium 233 and of the protactinium 233 in hydrochloric solution by absorption then selective elution on anion exchange resin. A precipitation of the thorium by the oxalic acid permits the recuperation of the hydrochloric acid which is recycled, the main, raw material consumed being the oxalic acid. (authors) [fr

  5. Uranium ores

    International Nuclear Information System (INIS)

    Poty, B.; Roux, J.

    1998-01-01

    The processing of uranium ores for uranium extraction and concentration is not much different than the processing of other metallic ores. However, thanks to its radioactive property, the prospecting of uranium ores can be performed using geophysical methods. Surface and sub-surface detection methods are a combination of radioactive measurement methods (radium, radon etc..) and classical mining and petroleum prospecting methods. Worldwide uranium prospecting has been more or less active during the last 50 years, but the rise of raw material and energy prices between 1970 and 1980 has incited several countries to develop their nuclear industry in order to diversify their resources and improve their energy independence. The result is a considerable increase of nuclear fuels demand between 1980 and 1990. This paper describes successively: the uranium prospecting methods (direct, indirect and methodology), the uranium deposits (economical definition, uranium ores, and deposits), the exploitation of uranium ores (use of radioactivity, radioprotection, effluents), the worldwide uranium resources (definition of the different categories and present day state of worldwide resources). (J.S.)

  6. Sequential automated fusion/extraction chromatography methodology for the dissolution of uranium in environmental samples for mass spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Milliard, Alex; Durand-Jezequel, Myriam [Laboratoire de Radioecologie, Departement de chimie, Universite Laval, 1045 Avenue de la Medecine, Quebec, QC, G1V 0A6 (Canada); Lariviere, Dominic, E-mail: dominic.lariviere@chm.ulaval.ca [Laboratoire de Radioecologie, Departement de chimie, Universite Laval, 1045 Avenue de la Medecine, Quebec, QC, G1V 0A6 (Canada)

    2011-01-17

    An improved methodology has been developed, based on dissolution by automated fusion followed by extraction chromatography for the detection and quantification of uranium in environmental matrices by mass spectrometry. A rapid fusion protocol (<8 min) was investigated for the complete dissolution of various samples. It could be preceded, if required, by an effective ashing procedure using the M4 fluxer and a newly designed platinum lid. Complete dissolution of the sample was observed and measured using standard reference materials (SRMs) and experimental data show no evidence of cross-contamination of crucibles when LiBO{sub 2}/LiBr melts were used. The use of a M4 fusion unit also improved repeatability in sample preparation over muffle furnace fusion. Instrumental issues originating from the presence of high salt concentrations in the digestate after lithium metaborate fusion was also mitigated using an extraction chromatography (EXC) protocol aimed at removing lithium and interfering matrix constituants prior to the elution of uranium. The sequential methodology, which can be performed simultaneously on three samples, requires less than 20 min per sample for fusion and separation. It was successfully coupled to inductively coupled plasma mass spectrometry (ICP-MS) achieving detection limits below 100 pg kg{sup -1} for 5-300 mg of sample.

  7. The TRansUranium EXtraction (TRUEX) process: A vital tool for disposal of US defense nuclear waste

    International Nuclear Information System (INIS)

    Horwitz, E.P.; Schulz, W.W.

    1990-01-01

    The TRUEX (TRansUranium EXtraction) process is a generic actinide extraction/recovery process for the removal of all actinides from acidic nitrate and chloride nuclear waste solutions. Because of its high efficiency and flexibility and its compatibility with existing process facilities, TRUEX has now become a vital tool for the disposal of certain US defense nuclear waste. The development of TRUEX is closely coupled to the development of bifunctional extractants belonging to the carbamoylphosphoryl class and CMPO in particular. A brief review of the development of CMPO and its relationship to other bifunctional and monofunctional extractants is presented. The effect of TBP on CMPO, the selectivity of CMPO for actinides extracted from acidic nitrate media, the influence of diluents on CMPO behavior and 3rd phase formation, and the radiolysis/hydrolysis of CMPO and subsequent solvent cleanup will be highlighted. Application of TRUEX in the chemical pretreatment of specific nuclear waste streams and a summary of the current status of development and deployment of TRUEX is presented. 15 refs., 10 figs., 3 tabs

  8. Box-Behnken design in modeling of solid-phase tea waste extraction for the removal of uranium from water samples

    International Nuclear Information System (INIS)

    Khajeh, Mostafa; Jahanbin, Elham; Ghaffari-Moghaddam, Mansour; Moghaddam, Zahra Safaei; Bohlooli, Mousa

    2015-01-01

    In this study, the solid-phase tea waste procedure was used for separation, preconcentration and determination of uranium from water samples by UV-Vis spectrophotometer. In addition, Box-Behnken experimental design was employed to investigated the influence of six variables including pH, mass of adsorbent, eluent volume, amount of 1-(2-pyridylazo)-2-naphthol (PAN); and sample and eluent flow rates on the extraction of analyte. High determination coefficient (R 2 ) of 0.972 and adjusted-R 2 of 0.943 showed the satisfactory adjustment of the polynomial regression model. This method was used for the extraction of uranium from real water samples.

  9. Preparation of 1-(2-pyridylazo)-2-naphthol functionalized benzophenone/naphthalene and their uses in solid phase extractive preconcentration/separation of uranium(VI)

    International Nuclear Information System (INIS)

    Preetha, C.R.; Prasada Rao, T.

    2003-01-01

    The preparation of solid reagent 1-(2-pyridylazo)-2-naphthol functionalized benzophenone/naphthalene for preconcentration/separation of uranium(VI) is described. These reagents enriches uranium(VI) quantitatively from dilute aqueous solutions in the pH range 10.5-11.0. The solid mixture consisting of the enriched metal ion along with solid phase extractant were dissolved in 2 ml of acetone and uranium(VI) content was established spectrophotometrically by using Arsenazo III procedure. Calibration graphs were rectilinear over the uranium(VI) concentration in the range 0.002-0.1 μg cm -3 . Five replicate determinations of 40 μg of uranium present in 1 dm 3 of sample solution gave a mean absorbance of 0.185 with a relative standard deviation of 1.4%. The detection limit (corresponding to 3 times the standard deviation of the blank) and the enrichment factor were found to be 2 μg dm -3 and 500 respectively. Further the possible separation of uranium(VI) from several bivalent, trivalent and tetravalent elements was also established. In addition to validating the developed method by successfully analysing marine sediment reference material (MESS-3), uranium content was established in soil, river and marine sediment samples by the developed method and compared with standard inductively coupled plasma mass spectrometry (ICP-MS) values. (orig.)

  10. Extraction and analysis of reducing alteration information of oil-gas in Bashibulake uranium ore district based on ASTER remote sensing data

    International Nuclear Information System (INIS)

    Ye Fawang; Liu Dechang; Zhao Yingjun; Yang Xu

    2008-01-01

    Beginning with the analysis of the spectral characteristics of sandstone with reducing alteration of oil-gas in Bashibulake ore district, the extract technology of reducing alteration information based on ASTER data is presented. Several remote sensing anomaly zones of reducing alteration information similar with that in uranium deposit are interpreted in study area. On the basis of above study, these alteration anomaly information are further classified by using the advantage of ASTER data with multi-band in SWIR, the geological significance for alteration anomaly information is respectively discussed. As a result, alteration anomalies good for uranium prospecting are really selected, which provides some important information for uranium exploration in outland of Bashibulake uranium ore area. (authors)

  11. Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Robin [Univ. of Alabama, Tuscaloosa, AL (United States)

    2013-12-21

    Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100{degrees}C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The

  12. Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

    International Nuclear Information System (INIS)

    Rogers, Robin

    2013-01-01

    Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100 deg C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The resulting

  13. Radiological evaluation near three old mines of uranium extraction in the department of Creuse - year 2007; Evaluation radiologique aux abords de trois anciennes mines d'extraction d'uranium du departement de la Creuse - annee 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The observations made for three sites of 'Chaumaillat, Ribiere and Grands Champs', demonstrate the existence of an atypical radiological situation which seems marked by the past activities of the mining. If the geochemical context can sometimes be at the origin of abnormalities in sediments and muds, the regional industrial context, conjugated to the strong measured values of uranium, incites us to privilege a human origin to explain these abnormalities. The presence of almost pure uraniums is the result supposed by the past activities of ore treatment on site (lixiviation) to extract the raw material from it (yellow cake) used for the manufacturing of the nuclear fuel. However, this observation on the site of 'Grands Champs' is surprising considering the absence of treatment activity in situ declared by the operator and the absence of residues storage.Given the accessibility of these sites to the public and considering the stop of any device of surveillance, a follow-up study seems necessary to estimate the importance of the radiological abnormalities and their persistent impact on the environment. (N.C.)

  14. Uranium extraction from aqueous solution using dried and pyrolyzed tea and coffee wastes

    International Nuclear Information System (INIS)

    Zaynab Aly

    2013-01-01

    The adsorption of U(VI) onto dried and pyrolyzed tea and coffee wastes was investigated. The adsorption properties of the materials were characterized by measuring uranium uptake as a function of solution pH, kinetics and adsorption isotherms. pH profile of uranium adsorption where UO 2 2+ is expected to be the predominant species was measured between pH 0 and 4. Both Langmuir and Freundlich adsorption models were used to describe adsorption equilibria, and corresponding constants evaluated. Using the Langmuir model, the maximum adsorption capacity of uranium by dried tea and coffee wastes was 59.5 and 34.8 mg/g, respectively at 291 K. Adsorption thermodynamic constants, ΔHdeg ΔSdeg and ΔGdeg were also calculated from adsorption data obtained at three different temperatures. Adsorption thermodynamics of uranyl ions on dried tea and coffee systems indicated spontaneous and endothermic processes. Additionally, a Lagergren pseudo-second-order kinetic model was used to fit the kinetic experimental data for both adsorbents and the constants evaluated. Dried tea and coffee wastes proved to be effective adsorbents with high capacities and significant advantage of a very low cost. (author)

  15. Determination of uranium and thorium in complex matrices by two solvent extraction separation techniques and photon electron rejecting alpha liquid spectrometry

    International Nuclear Information System (INIS)

    Ayranov, M.; Wacker, L.; Kraehenbuehl, U.

    2001-01-01

    The separation of uranium and thorium from complex matrixes such as marine sediments using solvent extraction and determination by means of photon-electron rejecting liquid alpha spectrometry (PERALS trademark) has successfully been performed. Two extraction schemes, using TOPO and HDEHP, respectively, were compared for the separation of uranium and thorium from the matrix components. The results show recoveries between 73 and 92% for 234 U, 238 U, 232 Th, 230 Th and 238 Th with an accuracy of the methods ±12%. Minimum detectable activities for counting time up to 500 000 seconds for 0.5 g sample material were between 0.34-1.15 Bq/kg for uranium and 0.31-1.66 Bq/kg for thorium. (orig.)

  16. Research over the extraction process in order to simulate 226Ra and Unat radionuclides migration in uranium waste dumps

    International Nuclear Information System (INIS)

    Bragea, Mihaela; Toro, Laszlo; Cristache, Carmen

    2008-01-01

    To simulate the phenomenon of migration availability of radioactive elements in uranium waste product from waste dump into the environment it was taken into account the Ciudanovita, Romania area with its uranium waste dumps. It were made studies through experiments of static extraction in agitation pot (static regime), which allow to pursue the evolution of contaminants along a specific period of time. It was accomplish a study about sorption and adsorption process on the geological environment (clay). It was observed that 226 Ra and U nat transition through the sorption and adsorption processes were induced by the type of clay (due to variable solubility of clay and the physics and chemical status of 226 Ra and U nat into the clay) and the time interval until the water contacts the clay. The concentration measurements of radionuclides into different dimension of clay particles were made to give pertinent information about the way of chosen the repair strategies for the studied site. The present work is based mainly on this research direction: optimization and improvement of the performances obtained from the geo-chemical processes investigation methods in the waste dumps and the surrounding geological structures to isolate them, in order to reduce the negative environmental impact. Measurements of the two radionuclides concentrations in particles with different dimensions were made to supply accurate information regarding the selection of remediation strategies for the dumpsite in study. (author)

  17. Complexation of vanadium with amidoxime and carboxyl groups. Uncovering the competitive role of vanadium in uranium extraction from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cong-Zhi; Wu, Qun-Yan; Lan, Jian-Hui; Shi, Wei-Qun [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics; Chai, Zhi-Fang [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics; Soochow Univ., Suzhou (China). School of Radiological and Interdisciplinary Sciences (RAD-X); Wu, Guo-Zhong [Chinese Academy of Sciences, Shanghai (China). Shanghai Inst. of Applied Physics

    2017-09-01

    At present, amidoxime-based adsorbents are considered to be the most promising materials for extraction of uranium from seawater. However, the high concentrations of transition metals especially vanadium strongly compete with uranium in the sequestration process, which is extremely limited the commercial use of amidoxime-based adsorbents. In this work, the coordination modes, bonding nature, and stabilities of possible vanadium(IV) (VO{sup 2+}) and (V) (VO{sub 2}{sup +}, VO{sup 3+}, V{sup 5+}) complexes with amidoximate (AO{sup -}), carboxyl (Ac{sup -}), glutarimidedioximate (HA{sup -}) and deprotonated glutarimidedioximate (A{sup 2-}) on single and double alkyl chains (R=C{sub 13}H{sub 26}) are systematically explored by quantum chemical calculations. Different from the uranyl (UO{sub 2}{sup 2+}) complexes, the AO{sup -} groups of the vanadium(IV) and (V) complexes prefer to coordinate as monodentate and chelate ligands, while few species with AO{sup -} groups in η{sup 2}-binding mode have been observed in the vanadium complexes. Besides, the vanadium complexes are predicted to have obvious covalent metal-ligand bonds. According to thermodynamic stability analysis, all the vanadium complexes with AO{sup -}, Ac{sup -}, HA{sup -} and A{sup 2-} ligands on double alkyl chains are found to be more stable than corresponding complexes with ligands on a single chain. The synergistic effect of the amidoxime and carboxyl groups can be observed in most of VO{sub 2}{sup +} and VO{sup 3+} complexes with mixed ligands (AO{sup -}/Ac{sup -}). The vanadium(IV) and (V) complexes are more stable than the corresponding uranyl complexes, and the adsorption capability of the amidoxime-based adsorbents toward vanadium(V) ions decrease in the order of VO{sub 2}{sup +}>VO{sup 3+}> V{sup 5+}. The dioxovanadium cation VO{sub 2}{sup +} is predicted to form multinuclear vanadium complex in the sequestration process, possibly resulting in higher stable VO{sub 2}{sup +} complexes. Therefore

  18. Purification of di-nonyl phenyl phosphoric acid (DNPPA) for synergistic extraction of uranium from strong phosphoric acid

    International Nuclear Information System (INIS)

    Singh, D.K.; Vijayalakshmi, R.; Singh, H.; Sharma, J.N.; Ruhela, R.

    2009-01-01

    Di-nonyl phenyl phosphoric acid (DNPPA) obtained from various synthesis methods is always associated with impurities such as mono-nonyl phenyl phosphoric acid and nonyl phenol which need to be separated for its effective use in the extraction of uranium from strong phosphoric acid. Two methods of purification namely liquid-solid separation method using neodymium salt and liquid-liquid separation method using methylene glycol have been described. In the liquid solid separation method the purity of DNPPA obtained was about 95% with less than 1.0% monoester, however it heavily suffers in the recovery aspect which is of the order of 50-60%. The methylene glycol treatment method, results in high purity and recovery of the product. Purity obtained was about 95.0% diester and less than 0.5% monoester and recovery was more than 90%. Analysis of DNPPA was done by potentiometric titration method using autotitrator. (author)

  19. Uranium sorption to natural substrates-insights provided by isotope exchange, selective extraction and surface complexation modelling approaches

    International Nuclear Information System (INIS)

    Waite, T.D.; Payne T.E.; Davis, J.A.

    1993-01-01

    An extensive experimental program has been conducted over the last three years into the interaction of U(VI) with both single oxides and clays and complex natural substrates from the weathered zone in the vicinity of a uranium ore body in northern Australia. While iron oxides have frequently been considered to account for much of the uptake on such natural substrates, the results of laboratory open-quotes pH edgeclose quotes studies and of isotope exchange and selective extraction studies suggest that other phases must also play a significant role in controlling the partitioning of U(VI) between solid and solution phases. Supporting studies on kaolinite, the dominant clay in this system, provide insight into the most appropriate method of modelling the interaction of U(VI) with these natural substrates. The problems still remaining in adequately describing sorption of radionuclides and trace elements to complex natural substrates are discussed

  20. Recovery of Uranium from Seawater: Modified Polyacrylonitrile Fibers as Selective Extractants

    Energy Technology Data Exchange (ETDEWEB)

    Alexandratos, Spiro D. [City Univ. (CUNY), NY (United States)

    2017-03-15

    A new bifunctional fiber has been prepared and found to have a significant loading capacity of uranium from real seawater. The fiber support is polyacrylonitrile and bifunctionality is provided by amidoxime and either diethylenetriamine (DETA) or ethylenediamine (EDA) ligands. The key feature is adjusting the hydrophilic /lipophilic balance within the fiber and this was best accomplished by partially acetylating or carboxylating EDA ligands. The bifunctional carboxylated EDA /AO fiber had a loading capacity of 3.83 mg U/g fiber at the Pacific Northwest National Laboratory with a 21 day contact time in real seawater.

  1. Removing oxygen from a solvent extractant in an uranium recovery process

    International Nuclear Information System (INIS)

    Hurst, F.J.; Brown, G.M.; Posey, F.A.

    1984-01-01

    An improvement in effecting uranium recovery from phosphoric acid solutions is provided by sparging dissolved oxygen contained in solutions and solvents used in a reductive stripping stage with an effective volume of a nonoxidizing gas before the introduction of the solutions and solvents into the stage. Effective volumes of nonoxidizing gases, selected from the group consisting of argon, carbon dioxide, carbon monoxide, helium, hydrogen, nitrogen, sulfur dioxide, and mixtures thereof, displace oxygen from the solutions and solvents thereby reduce deleterious effects of oxygen such as excessive consumption of elemental or ferrous and accumulation of complex iron phosphates or cruds

  2. Synthesis and characterization of new biopolymeric microcapsules containing DEHPA-TOPO extractants for separation of uranium from phosphoric acid solutions.

    Science.gov (United States)

    Outokesh, Mohammad; Tayyebi, Ahmad; Khanchi, Alireza; Grayeli, Fatemeh; Bagheri, Ghodrat

    2011-01-01

    A novel microcapsule adsorbent for separation of uranium from phosphoric acid solutions was developed by immobilizing the di(2-ethylhexyl) phosphoric acid-trioctyl phosphine oxide extractants in the polymeric matrix of calcium alginate. Physical characterization of the microcapsules was accomplished by scanning electron microscopy and thermogravimetric techniques. Equilibrium experiments revealed that both ion exchange and solvent extraction mechanisms were involved in the adsorption of [Formula: see text] ions, but the latter prevailed in a wider range of acid concentration. According to the results of kinetics study, at low acidity level, the rate controlling step was slow chemical reaction of [Formula: see text] ions with the microdroplets of extractant, whereas it changed to intraparticle diffusion at higher acid concentration. The study also attempted identification of the diffusion paths of the ions within the microcapsules, and the mechanism of change of mass transfer rate during the uptake process. The prepared microcapsules preserved their entire capacity after three cycles of adsorption, and their breakthrough behaviour was well fitted by a new formula derived from shrinking core model.

  3. Uranium(VI) and ruthenium extraction by dialkyldithio-phosphoric acids

    International Nuclear Information System (INIS)

    Fitoussi, R.; Musikas, C.

    1980-01-01

    Oxygen donors like dialkylphosphoric acids are good extractants for actinide ions, but little is known about their sulfur homologs. Investigations of U(VI) and Ru extraction from various aqueous media are reported. This includes extraction of U(VI) from nitric, perchloric, and phosphoric acids by solutions of dialkyldithiophosphoric acids in dodecane or benzene. Extraction of U(VI) by synergistic mixtures, of which at least one of the components is a sulfur donor, has been investigated. The extracted species have been identified, and a comparison with the complexes obtained by extraction with the homologous oxygen donors is made. The sulfur-actinide bond is weaker than the oxygen-actinide one, but in some synergistic extractions the dialkyldithiophosphonates are more efficient than the oxygen donors. In addition to size effects, this behavior could be attributed to the weakness of the hydrogen bonds of the SH groups, which allows a greater variety of the ligands to enter the coordination sphere of the metal. Ruthenium, like the d-transition elements, gives strong bonds with the sulfur donors. However, its extraction from nitric acid is slow. We investigated the influence of several parameters on the distribution coefficients and found that the presence of a reagent which destroys nitrous ions is necessary to achieve quantitative extraction. The role of RuNO groups is also discussed

  4. Development of a process for continuous extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Yun, C.K.

    1982-03-01

    Hydrous titanium oxide, titanium phosphate, galena (PbS), polystyrene beads containing TBP were preliminarily tested, using artificial seawater. Galena indicated the capacity of 1.1mg U/g PbS and faster reaction rates, whereas, hydrous titanium oxide showed 0.6mg U/g Ti and slow rates. The adsorption performance of galena was not changed after repeated use and regeneration with dil. HCl solutions. The effective surface of galena beads was 0.4mm in depth. Elution of uranium form adsorbents was examined by both acid and alkali methods; the latter showed preferred condition. Secondary concentration of uranium by Amberlite IRA-400 was also studies. Eventually, two types of packed systems with galena (columns and panels) were installed in the seawater channel of a thermal power plant. The maximum adsorption of 150μg U/g PbS was obtained using the packed column. Based on the experimental data, the authors made a conceptual design for a test plant of the production capacity 12Kg U 3 O 8 /y. The construction would cost about $1 million and the operation cost is estimated at $115.20/lb U 3 O 8

  5. Extraction of uranium (VI) from sea water using hydrous metalic oxide binded with hydrophilic polymers

    International Nuclear Information System (INIS)

    Shigetomi, Yasumasa; Kojima, Takehiro; Kamba, Hideaki

    1978-01-01

    In the past five years, many researches have been made to extract U(VI) from sea water. This is a report of the extraction of U(VI) from sea water using hydrous titanium oxide binded with hydrophilic polymers, the apparatus for the adsorption and the separation of U(VI) by means of ion exchange. (author)

  6. Impact of the uranium (VI) speciation in mineralised urines on its extraction by calix[6]arene bearing hydroxamic groups used in chromatography columns.

    Science.gov (United States)

    Baghdadi, S; Bouvier-Capely, C; Ritt, A; Peroux, A; Fevrier, L; Rebiere, F; Agarande, M; Cote, G

    2015-11-01

    Actinides determination in urine samples is part of the analyses performed to monitor internal contamination in case of an accident or a terrorist attack involving nuclear matter. Mineralisation is the first step of any of these analyses. It aims at reducing the sample volume and at destroying all organic compounds present. The mineralisation protocol is usually based on a wet ashing step, followed by actinides co-precipitation and a furnace ashing step, before redissolution and the quantification of the actinides by the appropriate techniques. Amongst the existing methods to perform the actinides co-precipitation, alkali-earth (typically calcium) precipitation is widely used. In the present work, the extraction of uranium(VI), plutonium(IV) and americium(III) from the redissolution solutions (called "mineralised urines") on calix[6]arene columns bearing hydroxamic groups was investigated as such an extraction is a necessary step before their determination by ICP-MS or alpha spectrometry. Difficulties were encountered in the transfer of uranium(VI) from raw to mineralised urines, with yield of transfer ranging between 0% and 85%, compared to about 90% for Pu and Am, depending on the starting raw urines. To understand the origin of such a difficulty, the speciation of uranium (VI) in mineralised urines was investigated by computer simulation using the MEDUSA software and the associated HYDRA database, compiled with recently published data. These calculations showed that the presence of phosphates in the "mineralised urines" leads to the formation of strong uranyl-phosphate complexes (such as UO2HPO4) which compete with the uranium (VI) extraction by the calix[6]arene bearing hydroxamic groups. The extraction constant of uranium (VI) by calix[6]arene bearing hydroxamic groups was determined in a 0.04 mol L(-1) sodium nitrate solution (logK=4.86±0.03) and implemented in an extraction model taking into account the speciation in the aqueous phase. This model allowed to

  7. Investigation on the efficience precipitation of uranium from kerosene solution of 2-di-ethylhexylphosphoric acid (D2EHPA) + TOPO after 2rd extraction process

    International Nuclear Information System (INIS)

    Misiak, R.; Tlalka, M.

    1985-01-01

    The model extraction systems: D2EHPA + TOPO + U(6) + kerosene -(NH 4 ) 2 CO 3 were examined on creation of the emulsion. The stability of the primary emulsions, dispersion type and the time of living were determined. Filtration possibilities under atmospheric and low pressure on ammonium-uranyl carbonate were investigated. The influence of temperature on velocity separation of the emulsion and the kinetics of stripping of uranium was given. Colorimetric method has been used for determination yield of the uranium. 2 refs., 8 figs. (author)

  8. Sequential extraction procedure for determination of uranium, thorium, radium, lead and polonium radionuclides by alpha spectrometry in environmental samples

    Science.gov (United States)

    Oliveira, J. M.; Carvalho, F. P.

    2006-01-01

    A sequential extraction technique was developed and tested for common naturally-occurring radionuclides. This technique allows the extraction and purification of uranium, thorium, radium, lead, and polonium radionuclides from the same sample. Environmental materials such as water, soil, and biological samples can be analyzed for those radionuclides without matrix interferences in the quality of radioelement purification and in the radiochemical yield. The use of isotopic tracers (232U, 229Th, 224Ra, 209Po, and stable lead carrier) added to the sample in the beginning of the chemical procedure, enables an accurate control of the radiochemical yield for each radioelement. The ion extraction procedure, applied after either complete dissolution of the solid sample with mineral acids or co-precipitation of dissolved radionuclide with MnO2 for aqueous samples, includes the use of commercially available pre-packed columns from Eichrom® and ion exchange columns packed with Bio-Rad resins, in altogether three chromatography columns. All radioactive elements but one are purified and electroplated on stainless steel discs. Polonium is spontaneously plated on a silver disc. The discs are measured using high resolution silicon surface barrier detectors. 210Pb, a beta emitter, can be measured either through the beta emission of 210Bi, or stored for a few months and determined by alpha spectrometry through the in-growth of 210Po. This sequential extraction chromatography technique was tested and validated with the analysis of certified reference materials from the IAEA. Reproducibility was tested through repeated analysis of the same homogeneous material (water sample).

  9. Uranium extraction from ores with lemon juice I,b-uranium recovery from pregnant lemon juice liquors obtained by attacking phosphate ores and suggested flowsheet

    International Nuclear Information System (INIS)

    EL-Sayed, M.H.

    1992-01-01

    In order to recover uranium from the pregnant liquors obtained by attacking safaga phosphate and qatrani phosphatic sandstone ore materials with lemon juice, methylation for acidic fraction-salt separation has been carried out. Afterwards, separation of uranium from the associated calcium (mainly present in lemon juice liquors as citrate) has been performed by making-use of the wide difference in their water solubility. The solutions containing the separated uranium were then subjected to evaporation till dryness whereby the precipitated uranyl citrate was calcined at 500 degree C to obtain the yellow orange oxide powder (U o 3 ). On the basis of one ton ore treatment, a flowsheet for uranium recovery from the two ore materials has been suggested

  10. Uranium extraction from ores with lemon juice; II,b. uranium recovery from pregnant lemon juice liquors obtained by attacking phosphate ore and suggested flowsheet

    International Nuclear Information System (INIS)

    Hussein, E.M.

    1997-01-01

    In order to recover uranium from the pregnant liquors obtained by attacking Safaga phosphate and Qatrani phosphatic sandstone ore materials with lemon juice, methylation for acidic fraction-salt separation has been carried out. Afterwards, separation of uranium from the associated calcium (mainly present in lemon juice liquors as citrate) has been performed by making-use of the wide difference in their water solubility. The solutions containing the separated uranium were then subjected to evaporation till dryness whereby the precipitated uranyl citrate was calcined at 500 degree C to obtain the yellow orange oxide powder (UO 3 ). On the basis of one ton ore treatment, a flowsheet for uranium recovery from the two ore materials has been suggested

  11. Development of a New Process for the Selective Extraction of Uranium from Phosphate Rocks

    International Nuclear Information System (INIS)

    Bernier, G.; Miguirditchian, M.; Pacary, V.; Balaguer, C.; Bertrand, M.; Camès, B.; Hérès, X.; Mokhtari, H.

    2014-01-01

    Conclusions: • Amido-phosphonate DEHCNPB is very promising for U extraction from phosphoric acid – Selective extraction of U even among high concentrations of iron in genuine 5 M H3PO4 solution : [Fe]/[U] reduced from 30 (feed) to 4.3 10-4 (product); • Parametric laboratory studies: – Characterize the stoichiometry of extracted complex in organic phase; – Propose extraction mechanisms; • Model developed and implemented in CEA PAREX code: – Modelling and flowsheet design; • Counter-current test on PROUST platform in G1 facility with genuine industrial phosphoric solution: – Treatment of an industrial phosphoric acid in laboratory-scale mixer-settlers; – Very promising performances of the run with good U recovery (91%) and good decontamination ([Fe] / [U] < ASTM specifications); – Experimental and calculated profiles of U and Fe in good agreement; • Experiments in progress to optimize this flowsheet

  12. New amides for uranium extraction: comparison between in silico predictions and experimental data

    International Nuclear Information System (INIS)

    Klimshuk, O.; Ouadi, A.; Billard, I.; Varnek, A.; Fourches, D.; Solov'ev, V.

    2006-01-01

    New methods and original software tools for computer-aided molecular design have been used to develop 'in silico' new monoamides which efficiently extract U(VI). A set of available experimental values of the uranyl partition coefficient (log D) in water/toluene system for 22 monoamides have been used by the ISIDA program in order to establish quantitative relationships between structure of the molecules and their extraction properties. Then, developed structure-property models have been applied to screen a virtual combinatorial library containing more than 2000 molecules. Selected hits have been synthesized and studied experimentally as extractants using the same protocol as for the molecules from the initial data set. Comparison between predicted and experimentally obtained log D values for new extractants is discussed. (author)

  13. Manhattan Project Technical Series The Chemistry of Uranium (I) Chapters 1-10

    International Nuclear Information System (INIS)

    Rabinowitch, E. I.; Katz, J. J.

    1946-01-01

    This constitutes Chapters 1 through 10. inclusive, of The Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Nuclear Properties of Uranium; Properties of the Uranium Atom; Uranium in Nature; Extraction of Uranium from Ores and Preparation of Uranium Metal; Physical Properties of Uranium Metal; Chemical Properties of Uranium Metal; Intermetallic Compounds and Alloy systems of Uranium; the Uranium-Hydrogen System; Uranium Borides, Carbides, and Silicides; Uranium Nitrides, Phosphides, Arsenides, and Antimonides.

  14. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented

  15. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

  16. Study of the physico-chemical agents influencing uranium and plutonium extraction by tributylphosphate in nitric media; Etude des facteurs physico-chimiques intervenant dans l'extraction de l'uranium et du plutonium par le phosphate de tributyle en milieu nitrique

    Energy Technology Data Exchange (ETDEWEB)

    Tarnero, M [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-03-01

    The following different factors are reviewed: tributylphosphate concentration, nitric acid concentration, influence of non-extractable nitrates, simultaneous presence of uranium and plutonium, presence of some different ions, temperature, nature of the diluent, addition of a second active solvent (synergic or antagonistic effect), tributylphosphate and diluent degradation. (author) [French] On passe en revue les differents facteurs suivants: concentration en phosphate de tributyle, concentration en acide nitrique, influence des nitrates non-extractibles, presence simultanee d'uranium et de plutonium, presence d'ions divers, addition d'un second solvant actif (effet de synergie, ou effet antagoniste), degradation du phosphate de tributyle et des solvants inertes. (auteur)

  17. Underground leaching - A method for the economic extraction of uranium from low-grade ores; Podzemnoe vyshchelachivanie - sposob ehkonomicheskogo izvlecheniya urana iz bednykh rud

    Energy Technology Data Exchange (ETDEWEB)

    Zefirov, A P [Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj EHnergii SSSR, Moskva, Union of Soviet Socialist Republics (Russian Federation)

    1967-06-15

    The method of underground leaching of uranium ores has a number of advantages over extraction followed by processing of the ores in factories. It has been studied in two types of deposit, occurring in rock masses and sandy shales. Research techniques were worked out accordingly for the leaching of uranium from large-grained ore (-200 mm) and from layers in natural stratification. Special models were constructed permitting the simulation of underground leaching conditions. The results obtained were checked in field conditions on experimental plots and experimental underground blocks. The investigations demonstrated the practicability of the process of underground leaching of uranium from certain ores and made it possible to work out flow-sheets and routines for an industrial process, information about which is given in the paper. (author)

  18. Effect of high ionic strength on the extraction of uranium(VI ions

    Directory of Open Access Journals (Sweden)

    M.K. Nazal

    2014-01-01

    Full Text Available Preparation and characterization of didodecylphosphoric acid (HDDPA as an extractant in toluene was carried. Mass spectroscopy showed that the monomer peak at 457.4 amu [M–Na+] is double that of the dimer at 891.9 amu [M–M–Na+] and the monomer molecules concentration dominate the dimer molecules in toluene. HDDPA was used as an extractant for the extraction of U(VI ion from perchlorate and nitrate media that have ionic strength (1.00, 3.00, 5.00, 7.00 M. The effect of HDDPA concentration, pcH, ionic strength of supporting electrolytes, and temperature in the range 15–45 °C on the extraction process have been studied. The stoichiometry of the extraction of U(VI ion, the free energy change (ΔG, the enthalpy change (ΔH, the entropy change (ΔS, and Kex at different ionic strength have been calculated. The formula of the complexes, which were formed has been established to be UO2(X(R2(HR2 at pcH equal 2.00 and UO2(X(R2(HR2 and UO2(X(R2 at pcH = 1.00, where (X isClO4- orNO3- and (HR2 is didodecylphosphoric acid monomer, (R2 is the deprotonated didodecylphosphoric acid, where R is the dodecyl group.

  19. Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Susan; Mohammadzadeh, Darush [Department of Chemistry, University of Birjand, Birjand (Iran); Yamini, Yadollah [Department of Chemistry, Tarbiat Moddars University, Tehran (Iran)

    2003-03-01

    A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 {mu}g L{sup -1} of uranyl. The method was applied to the recovery of uranyl from different water samples. (orig.)

  20. Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters

    International Nuclear Information System (INIS)

    Sadeghi, Susan; Mohammadzadeh, Darush; Yamini, Yadollah

    2003-01-01

    A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 μg L -1 of uranyl. The method was applied to the recovery of uranyl from different water samples. (orig.)

  1. A metallogenetic model of supergene extraction, releasing and enrichment in the mixed zone for granite-type uranium deposits in south China

    International Nuclear Information System (INIS)

    Li Minglian.

    1986-01-01

    The major geological features and their related geological events provide a base for the modelling of granite-type uranium deposits in South China. This paper presents a metallogenetic model to suggest the process of ore fluid circulation. There are two streams of ore fluids moving in the fracture zone: one comes from meteoric water and extracts uranium from wall rocks, flowing from top to bottom which is named uranium-loading fluid; another derives from the depth of the crust flowing from bottom to top and contains reducing matters as H 2 S etc. called uranium-releasing fluid. These two streams of solutions of different genesis, composition and character encountered and mixed at certain depth to precipitate the uranium. During the process the longitudinal circulation of underground thermal water in fracture zone results in the Bernoulli latitudinal circulation of ore fluids, which caused the ore fluids to ceaselessly flow into the minerogenetic location, where mineralization can be formed continuously in a certain period

  2. Separation Of Uranium From Fission Products Zr And Ru With 30% TBP (Tri Butyl Phosphate) Dodecane In Nitric Acid Medium As An Extract Material

    International Nuclear Information System (INIS)

    Herdady, R. Didiek; Masduki, Busron; Sigit

    2000-01-01

    Separation of uranium from fission products Zr and Ru in batch process with Tbp 30% - dodecane in nitric acid medium has been investigated. The extraction was carried out on various acidity of 1,006 M, 1.990 M, 2,980 M, 4,006 M, and 5,006 M, and uranium concentration in feed of 100.30 g/l; 149.96 g/l, 250.30 g/l and 300.7 g/l. The results showed that equilibrium of extraction was achieved at 25 minutes, enhancement factor of ruthenium increased and of zirconium decreased Utilization of grand concentration of uranium in feed caused decreasing of distribution coefficient, zirconium and ruthenium. The better contribution of experiments was obtained at the acidity of 2 M and uranium concentration in feed of 149.9 g/l with the decontamination factor of zirconium, FD zr-u was 1,65 and of ruthenium, FD ru-u was 1,52

  3. Application of alkaline leaching to the extraction of uranium from shale of the Vosges; Application de la lixiviation alcaline a l'extraction de l'uranium du schiste des Vosges

    Energy Technology Data Exchange (ETDEWEB)

    Mouret, P; Pottier, P; Le Bris, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Soudan, P [Centre d' Etude de Lalumine, Compagnie Pechiney (France)

    1958-07-01

    Description of chemical treatment of Vosges shales to obtain uranium by alkaline leaching. Mineralogy aspects of ore, physical and chemical conditions of leaching, solid/liquid separation, uranium recovery by either ion exchange process or electrolytic precipitation. (author)Fren. [French] Description du traitement chimique des schistes des Vosges pour extraire l'uranium en milieu alcalin. L'aspect mineralogique, les conditions physiques et chimiques de la lixiviation, la separation solide/liquide et la recuperation de l'uranium soit par echangeurs d'ions, soit par precipitation electrolytique y sont exposes. (auteur)

  4. A thorium breeder reactor concept for optimal energy extraction from uranium and thorium

    International Nuclear Information System (INIS)

    Jagannnathan, V.; Lawande, S.V.

    1999-01-01

    An attractive thorium breeder reactor concept has been evolved from simple physics based guidelines for induction of thorium in a major way in an otherwise enriched uranium reactor. D 2 O moderator helps to maximise reactivity for a given enrichment. A relatively higher flux level compared to LWRs offers the advantage of higher rate of 233 U production in thoria rods. Thus fresh thoria clusters consider no feed enrichment. In an equilibrium core, a full batch of pure thoria clusters are loaded during each fuel cycle. They undergo irradiation for about one year duration. By this time they accumulate nearly 70% of the asymptotic stable concentration of 233 U, if they face a flux level of the order of 10 14 n/cm 2 /sec. In the next fuel cycle, these thoria rods in ring cluster form are juxtaposed with the fresh enriched fuel rods, also in ring cluster form. Such integrated fuel assemblies are then irradiated for four or five fuel cycles, at the end of which U as well as Th rods attain a reasonably high burnup of about 30-32 MWD/kg. The core characteristics are quite attractive. The core excess reactivity remains low due to large thoria inventory which makes the net burnup reactivity load to be below 1%. The core is capable of being operated in an annual batch mode of operation like a LWR. The control requirement during power operation is negligible. Xenon over-ride requirement is low and can be managed by partial withdrawal of a few thoria clusters. Void reactivity is nearly zero or negative by the optimum design of the fuel cluster. Reactivity changes due to temperatures of fuel, coolant and moderator are also small. (author)

  5. Polarographic behaviour and determination of uranium(VI) in alcoholic solutions from organic extraction phases

    International Nuclear Information System (INIS)

    Degueldre, C.; Taibi, K.

    1996-01-01

    The determination of U(VI) in organic extraction phases: hydrocarbon-diethyl-2-hexyl phosphoric acid-trioctylphosphine oxide and hydrocarbon-tri-n-octylamine, diluted by an alcohol has been studied by direct current polarography, as well as by differential pulse polarography (DPP). In order to optimise the analytical procedure, miscibility and conductivity studies of the mixtures hydrocarbon-alcohol (ethanol, n- and isopropanol and n- and isobutanol) were made after addition of sulphuric acid as a supporting electrolyte. In the solutions of sulphuric acid in the alcohol-extractant-hydrocarbon phases, U(VI) gives rise to well defined polarograms. Its electroreduction involves a single electron step in all cases. The DPP peak height is proportional to the U(VI) concentration between 2x10 -6 and 2x10 -3 M, and the 3σ detection limit is ca. 10 -6 M

  6. Solvent extraction of uranium, thorium, and rare earths with dialkyldithiophosphoric acids

    International Nuclear Information System (INIS)

    Haiduc, I.; Curtui, M.

    1986-01-01

    The separation conditions for throium (IV) in the presence of trivalent rare earths was investigated. The distribution ratios (D), extraction effectivity values (E%) and separation factor(S) were calculated for binary systems Th-La, Th-Ce, Th-Pr, Th-Sm. Di-(2-ethyl-hexyl)dithiophosphoric acid (HEhdtp) alone or mixtures of HEhdtp and trioctylphosphoshine oxide (TOPO) can be successfully used for separation of Thorium (IV) and rare earths

  7. Rapid extraction of uranium from sea water using Fe{sub 3}O{sub 4} and humic acid coated Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, Pallavi, E-mail: psinghal@barc.gov.in [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Jha, Sanjay K. [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pandey, Shailaja P. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Neogy, Suman [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2017-08-05

    Highlights: • Uranium extraction using Fe{sub 3}O{sub 4} and HA coated Fe{sub 3}O{sub 4} NPs has been demonstrated. • Result indicates uranium extraction from both water and sea water matrix. • With increase in HA coating uranium extraction increases. • Fe{sub 3}O{sub 4}/HA 1 is the best material among synthesized one for uranium extraction. - Abstract: Uranium is one of the most toxic elements present in the environment and a number of methods have been developed for its extraction. Herein we have demonstrated a new method using magnetic nanoparticles (NPs) that can be used for uranium extraction from water and sea water matrix. Fe{sub 3}O{sub 4} and humic acid (HA) coated Fe{sub 3}O{sub 4} NPs with different amount of HA coating were synthesized and uranium sorption from water and sea water matrix was demonstrated. It was observed that sorption increases with increase in amount of HA coating. NPs settlement in presence of magnetic field was monitored where only bare Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}/HA 1 NPs settles while no settlement was observed for Fe{sub 3}O{sub 4}/HA 2 and Fe{sub 3}O{sub 4}/HA 3 NPs. Considering both sorption and particle separation from the matrix Fe{sub 3}O{sub 4}/HA 1 NPs are the best among synthesized ones with maximum sorption capacity of 10.5 mg of U/g of NPs. The results presented here reveal the exceptional potential of magnetic NPs and functionalized magnetic NPs for environmental remediation of uranium and to extract uranium from sea water on which to the best of our knowledge no report is available till now.

  8. Box-Behnken design in modeling of solid-phase tea waste extraction for the removal of uranium from water samples

    Energy Technology Data Exchange (ETDEWEB)

    Khajeh, Mostafa; Jahanbin, Elham; Ghaffari-Moghaddam, Mansour; Moghaddam, Zahra Safaei [Zabol Univ. (Iran, Islamic Republic of). Dept. of Chemistry; Bohlooli, Mousa [Zabol Univ. (Iran, Islamic Republic of). Dept. of Biology

    2015-07-01

    In this study, the solid-phase tea waste procedure was used for separation, preconcentration and determination of uranium from water samples by UV-Vis spectrophotometer. In addition, Box-Behnken experimental design was employed to investigated the influence of six variables including pH, mass of adsorbent, eluent volume, amount of 1-(2-pyridylazo)-2-naphthol (PAN); and sample and eluent flow rates on the extraction of analyte. High determination coefficient (R{sup 2}) of 0.972 and adjusted-R{sup 2} of 0.943 showed the satisfactory adjustment of the polynomial regression model. This method was used for the extraction of uranium from real water samples.

  9. Direct uranium extraction from dihydrate and hemi-dihydrate wet process phosphoric acids by liquid emulsion membrane

    International Nuclear Information System (INIS)

    El-Hazek, N.T.; El Sayed, M.S.

    2003-01-01

    A new liquid emulsion membrane (LEM) process for uranium extraction from either dihydrate 28-30% P 2 O 5 (DH) or hemi-dihydrate 42-45% P 2 O 5 (HDH) wet process phosphoric acid is proposed. In this process, the organic component of the LEM is composed of a synergistic mixture of 0.1M di-2-ethyl hexyl phosphoric acid (DEHPA) and 0.025M trioctyl phosphine oxide (TOPO) with 4% Span 80. The internal or the strip acid phase is composed of 0.5M citric acid. The prepared LEM was proved to be stable in 42-45% P 2 O 5 acid concentration range and can, therefore, be applied to the phosphoric acid produced by the hemi-dihydrate process. After breakdown of the loaded emulsion, the uranyl citrate in the internal strip phase is separated by adding methanol followed by its calcination to the orange oxide. Most of the reagents used are recycled. The proposed process is characterized by simplicity, practically closed operation cycle in addition to lower capital and operating costs. (author)

  10. Uranium and plutonium extraction by N,N-dialkyl-amides using multistage mixer-settler extractors

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Y.; Hotoku, S.; Tsutsui, N.; Suzuki, A.; Tsubata, Y.; Matsumura, T.

    2016-07-01

    N,N-Dialkyl-amides (mono-amides) are known as extractants for U and Pu, and many studies have been carried out mainly by single-stage batch method. We have focused on two mono amides: N,N-di(2-ethylhexyl)-2,2-dimethylpropanamide (DEHDMPA) and N,N-di(2-ethylhexyl)butanamide (DEHBA), and proposed a multistage extraction process for recovering U and Pu by these mono-amides. A continuous counter-current experiment was carried out to demonstrate the validity of this process. This process consisted of two cycles, and the first cycle and the second cycle employed DEHDMPA and DEHBA as extractants, respectively. The feed solution for the first cycle was 5.1 mol/dm{sup 3} (M) nitric acid containing 0.92 M U, 1.6 mM Pu, and 0.6 mM Np. The raffinate collected in the first cycle was used as the feed for the second cycle. The ratios of U recovered in the U fraction and U-Pu fraction were 99.1% and 0.8%, respectively, and the ratios of U in the used solvents were <0.04%. The ratio of Pu recovered in the U-Pu fraction was 99.7%, and the ratio of Pu in the used solvents was in the order of 10{sup -3} - 10{sup -4}%. The concentration ratio of U with respect to Pu in the U-Pu fraction was 9, and this indicated that Pu was not isolated. The decontamination factor of U with respect to Pu in the U fraction was obtained as 4.5*10{sup 5}. These results supported the validity of the proposed process. (authors)

  11. Theoretical treatment of equilibrium data and evaluation of diffusion coefficients in extraction of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Manohar, Smitha; Theyyunni, T K [Process Engineering and Systems Development Division, Bhabha Atomic Research Centre, Mumbai (India); Ragunathan, T S [Department of Chemical Engineering, Indian Inst. of Tech., Mumbai (India)

    1994-06-01

    A meaningful approach to the calculation of the performance of solvent extraction contactors in the PUREX process requires a good understanding of the equilibrium distribution of the important constituents, namely uranyl nitrate and nitric acid. Published literature refers to the empirical correlation of the distribution data, generally in the form of polynomials. Attempts are made to describe the distribution data in a form which is specially convenient for numerical computations along with its theoretical significance. Attempts are also made to derive suitable equations which would aid in estimation of diffusion coefficients in the uranyl nitrate-nitric acid-TBP/diluent system. (author). 2 tabs.

  12. Reversed phase column extraction studies to recovery of uranium using a modified perlite

    International Nuclear Information System (INIS)

    Akcay, H.

    2006-01-01

    Reversed phase column (RPC) extraction chromatography is an useful technique and has been carried out successfully to the separation of various metals and organic compounds. Its application has received considerable attention because it combines the selectivity of LLE with the advantage of chromatography. The efficiency of the separation by RPC depends on both the chemical and physical properties of the solid support and the stationary phase. This work describes the preparation of an improved adsorbent from natural perlite and its properties to uptake of uranyl ion. Perlite is a volcanic glassy rock produced in commercially workable quantities from mines of Aegean region of Turkey and contains 70-75% CO 2 .The CO 2 was converted to soluble silicates with NaOH modification then its acidification to form hydrogen which turned into xerogels upon drying. Fundamental parameters (particle size, specific surface area, pore size and volume, surface hydroxyl group density) were determined for modified perlite and it was silanized then loaded with 20% (w/w) TBP before being used as reversed phase column chromatography solid support. Finally the sorption of UO 2 + 2 from aqueous solutions by the modified perlite was investigated using Batch techniques. The use of TBP-loaded perlite as a reversed phase column (RPC) extraction chromatography support seems to be useful to uptake of UO 2 + 2 from aqueous solutions and to separate from various cations

  13. Spectrophotometric determination of uranium with arsenazo previous liquid-liquid extraction and colour development in organic medium; Determinacion espectrofotometrica de uranio con arsenazo, previa extraccion y desarrollo del color en medio organico

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Delgado, F; Vera Palomino, J; Petrement Eguiluz, J C

    1964-07-01

    The determination of uranium with arsenazo is hindered by a great number of cation which form stable complexes with the reactive and may given rise to serious interferences. By studying the optimum conditions of uranium the extraction be means of tributylphosphate solutions dissolved in methylisobuthylketone, under conditions for previous masking of the interfering cations, an organic extract was obtained containing all the uranium together with small amounts of iron. The possible interference derived from the latter element is avoided by reduction with hydroxylammoniumchlorid followed by complex formation of the Fe(II)-ortophenantroline compound in alcoholic medium. (Author) 17 refs.

  14. Determination of small amounts of nitric acid in the presence of large amounts of uranium (VI) and extraction of nitric acid into TBP solutions highly loaded with uranyl nitrate

    International Nuclear Information System (INIS)

    Kolarik, Z.; Schuler, R.

    1982-10-01

    A new method for the determination of small amounts of nitric acid in the presence of large amounts of uranium(VI) was elaborated. The method is based on the precipitation of uranium(VI) as iodate and subsequent alkalimetric titration of the acid in the supernatant. The extraction of nitric acid and uranium(VI) with 30% TBP in dodecane was studied at high loading of the organic phase with uranyl nitrate and at 25, 40 and 60 0 C. The results are compared with available published data on the extraction of nitric acid under similar conditions. (orig.) [de

  15. The Effect of pH and Time on the Extractability and Speciation of Uranium(VI) Sorbed to SiO2

    International Nuclear Information System (INIS)

    Ilton, Eugene S.; Wang, Zheming; Boily, Jean F.; Qafoku, Odeta; Rosso, Kevin M.; Smith, Steven C.

    2012-01-01

    The effect of pH and contact time on uranium extractability from quartz surfaces was investigated using either acidic or carbonate (CARB) extraction solutions, time-delayed spikes of different U isotopes (i.e., 238U and 233U), and liquid helium temperature time-resolved laser-induced fluorescence spectroscopy (LHeT TRLFS). Quartz powders were reacted with 238U(VI) bearing solutions that were equilibrated with atmospheric CO2 at pH 6, 7, and 8. After a 42 day equilibration period with 238U(VI), the suspensions were spiked with 233U(VI) and reacted for an additional 7 days. Sorbed U was then extracted with either dilute nitric acid or CARB. For the CARB extraction there was a systematic decrease in extraction efficiency for both isotopes from pH 6 to 8. This was mimicked by less desorption of 238U, after the 233U spike, from pH 6 to 8. Further, the efficiency of 233U extraction was consistently greater than that of 238U, indicating a strong temporal component to the strength of U association with the surface that was accentuated with increasing pH. LHeT TRLFS revealed a strong correlation between carbonate extraction efficiency and differences in sorbed U speciation as a function of pH. In contrast, the acid extraction was consistently more efficient than the CARB extraction, with a smaller dependence on both pH and aging time. Collectively, the observations show that aging and pH are critical factors in determining the form and strength of uranium-silica interactions.

  16. Trace metal distribution and mobility in drill cuttings and produced waters from Marcellus Shale gas extraction: Uranium, arsenic, barium

    International Nuclear Information System (INIS)

    Phan, Thai T.; Capo, Rosemary C.; Stewart, Brian W.; Graney, Joseph R.; Johnson, Jason D.; Sharma, Shikha; Toro, Jaime

    2015-01-01

    Highlights: • Distributions of U, As, and Ba in Marcellus Shale were determined. • As is primarily associated with sulfide minerals, Ba with exchange sites. • Most U is in the silicate minerals, but up to 20% is partitioned into carbonate. • Low [U] and [As] in produced water are consistent with reducing downhole conditions. • Proper waste management should account for potential mobilization of U and As. - Abstract: Development of unconventional shale gas wells can generate significant quantities of drilling waste, including trace metal-rich black shale from the lateral portion of the drillhole. We carried out sequential extractions on 15 samples of dry-drilled cuttings and core material from the gas-producing Middle Devonian Marcellus Shale and surrounding units to identify the host phases and evaluate the mobility of selected trace elements during cuttings disposal. Maximum whole rock concentrations of uranium (U), arsenic (As), and barium (Ba) were 47, 90, and 3333 mg kg −1 , respectively. Sequential chemical extractions suggest that although silicate minerals are the primary host for U, as much as 20% can be present in carbonate minerals. Up to 74% of the Ba in shale was extracted from exchangeable sites in the shale, while As is primarily associated with organic matter and sulfide minerals that could be mobilized by oxidation. For comparison, U and As concentrations were also measured in 43 produced water samples returned from Marcellus Shale gas wells. Low U concentrations in produced water (<0.084–3.26 μg L −1 ) are consistent with low-oxygen conditions in the wellbore, in which U would be in its reduced, immobile form. Arsenic was below detection in all produced water samples, which is also consistent with reducing conditions in the wellbore minimizing oxidation of As-bearing sulfide minerals. Geochemical modeling to determine mobility under surface storage and disposal conditions indicates that oxidation and/or dissolution of U

  17. Uranium mining

    International Nuclear Information System (INIS)

    2008-01-01

    Full text: The economic and environmental sustainability of uranium mining has been analysed by Monash University researcher Dr Gavin Mudd in a paper that challenges the perception that uranium mining is an 'infinite quality source' that provides solutions to the world's demand for energy. Dr Mudd says information on the uranium industry touted by politicians and mining companies is not necessarily inaccurate, but it does not tell the whole story, being often just an average snapshot of the costs of uranium mining today without reflecting the escalating costs associated with the process in years to come. 'From a sustainability perspective, it is critical to evaluate accurately the true lifecycle costs of all forms of electricity production, especially with respect to greenhouse emissions, ' he says. 'For nuclear power, a significant proportion of greenhouse emissions are derived from the fuel supply, including uranium mining, milling, enrichment and fuel manufacture.' Dr Mudd found that financial and environmental costs escalate dramatically as the uranium ore is used. The deeper the mining process required to extract the ore, the higher the cost for mining companies, the greater the impact on the environment and the more resources needed to obtain the product. I t is clear that there is a strong sensitivity of energy and water consumption and greenhouse emissions to ore grade, and that ore grades are likely to continue to decline gradually in the medium to long term. These issues are critical to the current debate over nuclear power and greenhouse emissions, especially with respect to ascribing sustainability to such activities as uranium mining and milling. For example, mining at Roxby Downs is responsible for the emission of over one million tonnes of greenhouse gases per year and this could increase to four million tonnes if the mine is expanded.'

  18. Pyrometallurgical partitioning of uranium and transuranic elements from rare earth elements by electrorefining and reductive extraction

    International Nuclear Information System (INIS)

    Uozumi, Koichi; Kinoshita, Kensuke; Inoue, Tadashi; Storvick, T.S.; Krueger, C.L.; Nabelek, C.R.

    2001-01-01

    High-level liquid waste generated from PUREX reprocessing contains a small amount of transuranic elements, such as Np, Pu, Am, and Cm, with long-lived radioactivities. A pyrometallurgical partitioning process is being developed to recover transuranic elements from such waste. Small amounts of U contained in the high-level liquid waste are also recovered in the process. A key issue for developing the process is effective separation of U and the transuranic elements from the rare-earth elements, because the two elemental groups are chemically analogous. A series of process tests were carried out in the present study to demonstrate that a combination of electrorefining and reductive extraction is useful for separating U and transuranic elements from the rare-earth elements. The results indicate that 99% of U and each transuranic elements is recovered by the combination process as a product, and that the quantity of rare-earth elements contained in the product is smaller than the transuranic elements by weight. The overall mass balance of U and transuranic elements in the system ranged within the experimental errors assigned to sampling and analysis. (author)

  19. Extraction of uranium(6), transuranium elements and europium by bidentate neutral phosphorus- and phosphorus-nitrogen-containing reagents with substituent in methylene bridge

    International Nuclear Information System (INIS)

    Kochetkova, N.E.; Kojro, O.Eh.; Nesterova, N.P.; Medved', T.Ya.; Chmutova, M.K.; Myasoedov, B.F.; Kabachnik, M.I.

    1986-01-01

    The influence of substituents in methylene bridge on solubility, extractivity and selectivity of bidentate neutral phosphorus- and phosphorus-nitrogen-containing reagents in the process of U(6), TUE, Eu extraction has been studied. It is ascertained that hydrogen substitution in the bridge of tetraphenylmethylenediphosphine dioxide (1) causes a decrease in the extractivity of reagent as to TPE, uranium (6) and europium. There is no visible regular relation between basicity and extractivity of substituted reagents. Hydrogen substitution in the bridge of diphenyl[diethylcarbamoylmethyl]phosphine oxide (2) causes a decrease in extractivity of the reagent as to TPE, uranium (6) and europium. In contrast to monodentate neutral reagents, when bidentate neutral reagents are used, sometimes no increase in the reagent extractivity with an increase in its basicity is observed. When fragments restricting the conformation mobility of bidentate reagent molecule are introduced in it (here substituents in methylene bridge), it may result in the violation of the regularity, since of all the factors affecting the reagent extractivity the spatial factor may become the prevailing one. On hydrogen substitution in the bridge of 1 separation factors of practically all (with few exceptions) studied pairs of elements increase. Hydrogen substitution in the bridge of 2 causes an increase in separation factor of U (6) /Am pair and it does not affect the separation factor of Am/Eu pair. Hydrogen substitution in the bridge of 1 and 2 does not result in the preparation of more efficient and considerably more selective reagents for extractive isolation and separation of the elements, but some of the substituted reagents (Cl-substituted 1, for instance) may turn out useful for the element separation

  20. On-line solid phase extraction using ion-pair microparticles combined with ICP-OES for the simultaneous preconcentration and determination of uranium and thorium

    Energy Technology Data Exchange (ETDEWEB)

    Yousefi, Seyed Reza; Zolfonoun, Ehsan [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). NFCRS

    2016-07-01

    In this work, after on-line and in-situ solid phase extraction technique was used for the extraction and preconcentration of uranium and thorium from aqueous samples prior to inductively coupled plasma optical emission spectrometry (ICP-OES) determination. In this method, sodium hexafluorophosphate (as an ion-pairing agent) was added to the sample solution containing the cationic surfactant (dodecyltrimethylammonium bromide) and the complexing agent (dibenzoylmethane). A cloudy solution was formed as a result of formation of an ion pair between surfactant and hexafluorophosphate. The solid microparticles were passed through a microcolumn filter and the adsorbed microparticles were subsequently eluted with acid, which was directly introduced into the ICP-OES nebulizer. The main variables affecting the pre-concentration and determination steps of uranium and thorium were studied and optimized. Under the optimum conditions, the enhancement factors of 97 and 95 and the detection limits of 0.52 and 0.21 μg L{sup -1} were obtained for uranium and thorium, respectively.

  1. Preconcentration of uranium in water samples using dispersive liquid-liquid micro- extraction coupled with solid-phase extraction and determination with inductively coupled plasma-optical emission spectrometry

    Directory of Open Access Journals (Sweden)

    M. Rezaee,

    2015-10-01

    Full Text Available A new liquid phase microextraction method based on the dispersion of an extraction solvent into aqueous phase coupled with solid-phase extraction was investigated for the extraction, preconcentration and determination of uranium in water samples. 1-(2-Pyridylazo-2-naphthol reagent (PAN at pH 6.0 was used as a chelating agent prior to extraction. After concentration and purification of the samples in SPE C18 sorbent, 1.5 mL elution sample containing 40.0 µL chlorobenzene was injected into the 5.0 mL pure water. After extraction and centrifuging, the sedimented phase was evaporated and the residue was dissolved in nitric acid (0.5 M and was injected by injection valve into the ICP-OES. Some important extraction parameters, such as sample solution flow rate, sample pH, type and volume of extraction and disperser solvents as well as the salt addition were studied and optimized. Under the optimum conditions, the calibration graph was linear in the range of 0.5-500 µg L-1. The detection limit was 0.1 µg L-1. The relative standard deviation (RSD at 5.0 µg L-1 concentration level was 6.6%. Finally, the developed method was successfully applied to the extraction and determination of uranium in the well, river, mineral, waste and tap water samples and satisfactory results were obtained.DOI: http://dx.doi.org/10.4314/bcse.v29i3.4

  2. Zinc and palladium traces separation from uranium by tri-n-octylamine extraction. Direct determination in organic phase by atomic absorption

    Energy Technology Data Exchange (ETDEWEB)

    de Moraes, S; Cipriani, M; Abrao, A

    1974-12-01

    A procedure for the extraction and determination of Zn and Pd as traces from nuclear grade uranium ADU, UO/sub 2/, UO/sub 3/, U/sub 3/O/sub 8/ is introduced. The elements are extracted from UO/sub 2/Cl/sub 2/-HCl-KI solution with tri-n-octylamine in benzene and determined by atomic absorption spectrophotometry. The adition of potassium iodide to the UO/sub 2/Cl/sub 2/-HCl solutions improved the extraction of both elements. Direct burn of the organic phase in the atomic absorption spectrophotometer using hydrogen-air flame provided enhancement of the absorbance for both elements. The relative standard deviations were Zn, 3% and Pd, 2.9%.

  3. Scale-up of mixer-settler for uranium extraction; Determinacao das relacoes de `scale-up` em misturador-decantador tipo caixa utilizado na extracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Santana, A.O. de

    1990-05-01

    The aim of this work was to obtain scale-up relations for a box type mixer-settler used in uranium extraction process for chloridric leaches. Three box type units with different sizes and with the same geometry were used for scale-up of the mixer. The correlation between extraction rate and specific power input, D/T ratio (stirrer diameter/mixer length) and residence time were experimentally obtained. The results showed that the extraction increases with power input for a constant value of D/T equal to 1/3, remaining however independent from mixer sizes for a specific value of power input. This behavior was observed for power input values ranging from 100 to 750 w/m{sup 9}. (author). 23 refs, 22 figs, 23 tabs.

  4. Uranium chemistry research unit

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    The initial field of research of this Unit, established in 1973, was the basic co-ordination chemistry of uranium, thorium, copper, cobalt and nickel. Subsequently the interest of the Unit extended to extractive metallurgy relating to these metals. Under the term 'co-ordination chemistry' is understood the interaction of the central transition metal ion with surrounding atoms in its immediate vicinity (within bonding distance) and the influence they have on each other - for example, structural studies for determining the number and arrangement of co-ordinated atoms and spectrophotometric studies to establish how the f electron energy levels of uranium are influenced by the environment. New types of uranium compounds have been synthesized and studied, and the behaviour of uranium ions in non-aqueous systems has also received attention. This work can be applied to the development and study of extractants and new extractive processes for uranium

  5. Recovery of uranium from crude uranium tetrafluoride

    International Nuclear Information System (INIS)

    Ghosh, S.K.; Bellary, M.P.; Keni, V.S.

    1994-01-01

    An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author)

  6. Recovery of uranium from crude uranium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S K; Bellary, M P; Keni, V S [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author). 4 refs., 1 fig., 3 tabs.

  7. Irradiated uranium reprocessing; Prerada ozracenog urana

    Energy Technology Data Exchange (ETDEWEB)

    Gal, I [Institute of Nuclear Sciences Boris Kidric, Laboratorijaza visoku aktivnost, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    Task concerned with reprocessing of irradiated uranium covered the following activities: implementing the method and constructing the cell for uranium dissolving; implementing the procedure for extraction of uranium, plutonium and fission products from radioactive uranium solutions; studying the possibilities for using inorganic ion exchangers and adsorbers for separation of U, Pu and fission products.

  8. Recovery of uranium from uranium bearing black shale

    International Nuclear Information System (INIS)

    Das, Amrita; Yadav, Manoj; Singh, Ajay K.

    2016-01-01

    Black shale is the unconventional resource of uranium. Recovery of uranium from black shale has been carried out by the following steps: i) size reduction, ii) leaching of uranium in the aqueous medium, iii) fluoride ion removal, iv) solvent extraction of uranium from the aqueous leach solution, v) scrubbing of the loaded solvent after extraction to remove impurities as much as possible and vi) stripping of uranium from the loaded organic into the aqueous phase. Leaching of black shale has been carried out in hydrochloric acid. Free acidity of the leach solution has been determined by potentiometric titration method. Removal of fluoride ions has been done using sodium chloride. Solvent extraction has been carried out by both tributyl phosphate and alamine-336 as extractants. Scrubbing has been tried with oxalic acid and sulphuric acid. Stripping with sodium carbonate solution has been carried out. Overall recovery of uranium is 95%. (author)

  9. Recovery of uranium values

    International Nuclear Information System (INIS)

    Rowden, G.A.

    1982-01-01

    A process is provided for the recovery of uranium from an organic extractant phase containing an amine. The extractant phase is contacted in a number of mixing stages with an acidic aqueous stripping phase containing sulphate ions, and the phases are passed together through a series of mixing stages while maintaining a dispersion of droplets of one phase in the other. Uranium is precipitated from the final stage by raising the pH. An apparatus having several mixing chambers is described

  10. Formerly utilized MED/AEC Sites Remedial Action Program. Radiological survey of the former VITRO Rare Metals Plant, Canonsburg, Pennsylvania. Final report. [Plant to extract radium and uranium

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    This 18-acre site was used from 1911 to 1922 to extract radium from carnotite ore, from 1930 to 1942 to extract radium and uranium salts from onsite residues and carnotite ore, and from 1942 to 1957 to recover uranium from various ores and scrap materials. The radiological survey was conducted in two phases, Phase I included measurement of radon and radon daughter concentrations in onsite buildings; concentrations measured in this part of the survey were all above guideline levels. Phase II consisted of measurement of surface contamination levels on the site, external gamma radiation levels at 1 m above surfaces on and near the site, radionuclide concentrations in surface and subsurface soil and water on and near the site, and radon concentrations in air at offsite locations. The results of the second phase of the survey indicate that large quantities of the radioactive wastes generated during radium and uranium recovery operations still remain on the site. Radium-bearing wastes are present in soil beneath or adjacent to each of the buildings on the site and in the top few feet of soil over almost the entire site, with some areas being contaminated to a depth of 16 ft or more. Alpha contamination levels, beta--gamma dose rates, and external gamma radiation levels in some areas of the buildings and outdoors on the site are above current federal guidelines concerning the release of property for unrestricted use. Concentrations of /sup 226/Ra in water in holes drilled on the site are above the maximum permissible concentration (MPC/sub w/). Also, measurements made offsite show that contamination from the site has spread to nearby offsite locations, and that there is significant atmospheric transport of /sup 222/Rn from the site.

  11. Uranium production

    International Nuclear Information System (INIS)

    Spriggs, M.

    1980-01-01

    The balance between uranium supply and demand is examined. Should new resources become necessary, some unconventional sources which could be considered include low-grade extensions to conventional deposits, certain types of intrusive rock, tuffs, and lake and sea-bed sediments. In addition there are large but very low grade deposits in carbonaceous shales, granites, and seawater. The possibility of recovery is discussed. Programmes of research into the feasibility of extraction of uranium from seawater, as a by-product from phosphoric acid production, and from copper leach solutions, are briefly discussed. Other possible sources are coal, old mine dumps and tailings, the latter being successfully exploited commercially in South Africa. The greatest constraints on increased development of U from lower grade sources are economics and environmental impact. It is concluded that apart from U as a by-product from phosphate, other sources are unlikely to contribute much to world requirements in the foreseeable future. (U.K.)

  12. An extraction method of uranium 233 from the thorium irradiates in a reactor core; Une methode d'extraction de l'uranium-233 a partir du thorium irradie dans une pile

    Energy Technology Data Exchange (ETDEWEB)

    Chesne, A; Regnaut, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Description of the conditions of separation of the thorium, of the uranium 233 and of the protactinium 233 in hydrochloric solution by absorption then selective elution on anion exchange resin. A precipitation of the thorium by the oxalic acid permits the recuperation of the hydrochloric acid which is recycled, the main, raw material consumed being the oxalic acid. (authors) [French] Description des conditions de separation du thorium, de l'uranium 233 et du protactinium 233 en solution chlorhydrique par absorption puis elution selective sur resine echangeuse d'anions. Une precipitation du thoriun par l'acide oxalique permet la recuperation de l'acide chlorhydrique qui est recycle, la principale matiere premiere consommee etant l'acide oxalique. (auteurs)

  13. Uranium of Kazakhstan

    International Nuclear Information System (INIS)

    Tsalyuk, Yu.; Gurevich, D.

    2000-01-01

    Over 25 % of the world's uranium reserves are concentrated in Kazakhstan. So, the world's largest Shu-Sarysu uranium province is situated on southern Kazakhstan, with resources exceeding 1 billion tonnes of uranium. No less, than 3 unique deposits with resources exceeding 100,000 tonnes are situated here. From the economic point of view the most important thing is that these deposits are suitable for in-situ leaching, which is the cheapest, environmentally friendly and most efficient method available for uranium extracting. In 1997 the Kazatomprom National Joint-Stock Company united all Kazakhstan's uranium enterprises (3 mine and concentrating plants, Volkovgeologiya Joint-Stock Company and the Ulbinskij Metallurgical plant). In 1998 uranium production came to 1,500 tonnes (860 kg in 1997). In 1999 investment to the industry were about $ 30 million. Plans for development of Kazakhstan's uranium industry provide a significant role for foreign partners. At present, 2 large companies (Comeco (Canada), Cogema (France) working in Kazakhstan. Kazakatomprom continues to attract foreign investors. The company's administration announced that in that in next year they have plan to make a radical step: to sell 67 % of stocks to strategic investors (at present 100 % of stocks belongs to state). Authors of the article regard, that the Kazakhstan's uranium industry still has significant reserves to develop. Even if the scenario for the uranium industry could be unfavorable, uranium production in Kazakhstan may triple within the next three to four years. The processing of uranium by the Ulbinskij Metallurgical Plant and the production of some by-products, such as rhenium, vanadium and rare-earth elements, may provide more profits. Obviously, the sale of uranium (as well as of any other reserves) cannot make Kazakhstan a prosperous country. However, country's uranium industry has a god chance to become one of the most important and advanced sectors of national economy

  14. Uranium in South Africa

    International Nuclear Information System (INIS)

    Ford, M.A.

    1993-01-01

    The history, sources, mineralogy, extraction metallurgy, conversion, and enrichment of uranium in South Africa is reviewed. Over the past 40 years extraction plants were built at 27 sites, and over 140 kt of uranium have been produced. Older plants have had to adapt to changing market conditions, no single technology has had the opportunity to become entrenched, and the costs have been reduced to a third of those of the original flowsheet. The research efforts aimed at developing the country's nuclear raw materials have been particularly rewarding, as they have enabled South Africa to become a world leader in the extraction of uranium from low-grade ores and to develop methods for uranium enrichment and the production of nuclear fuels. 43 refs., 7 figs., 4 tabs

  15. Early uranium mining in the United States

    International Nuclear Information System (INIS)

    Hahne, F.J.

    1990-01-01

    Uranium mining in the United States is closer to 100 years old than to the 200 years since the discovery of the element. Even then, for much of this time the rock was brought out of the ground for reasons other than its uranium content. The history of the US uranium industry is divided into five periods which follow roughly chronologically upon one another, although there is some overlap. The periods cover: uranium use in glass and ceramics; radium extraction; vanadium extraction; government uranium extraction and commercial extraction. (author)

  16. Extractive separation of uranium(VI) as perchlorate/chloroacetate complexes with 1-phenyl-2,3 dimethyl-5-pyrazolone and its applications

    International Nuclear Information System (INIS)

    Bose, R.; Murty, D.S.R.

    2003-01-01

    The extraction of U(VI) with 1-phenyl 2,3 dimethyl-5-pyrazolone, at a pH of 2.5, in the presence of common anions, like perchlorate and tri-, di-, and monochloroacetates has been investigated. The optimum experimental conditions have been evaluated by studying various parameters such as pH, equilibration period, reagent concentration, metal concentration, and solvents. Effect of diverse anions and cations on the extraction has also been studied. The extracted species, determined by log D - log R plots are represented as, [UO 2 (Apy) 4 (ClO 4 ) 2 ], [UO 2 (Apy) 2 (TCA) 2 ], [UO 2 (Apy) 2 (DCA) 2 ], [UO 2 (Apy)(H 2 O)(MCA) 2 ]. The conditional stability constants of the quantitatively extracted complexes are calculated. The proposed method allows the selective separation of uranium(VI) from multicomponent mixtures and geological matrices and is also applied for the separation and chemical characterization of impurities at trace and ultratrace levels. (author)

  17. Uranium's scientific history

    International Nuclear Information System (INIS)

    Goldschmidt, B.

    1990-01-01

    The bicentenary of the discovery of uranium coincides with the fiftieth anniversary of the discovery of fission, an event of worldwide significance and the last episode in the uranium -radium saga which is the main theme of this paper. Uranium was first identified by the German chemist Martin Klaproth in 1789. He extracted uranium oxide from the ore pitchblende which was a by-product of the silver mines at Joachimsthal in Bohemia. For over a century after its discovery, the main application for uranium derived from the vivid colours of its oxides and salts which are used in glazes for ceramics, and porcelain. In 1896, however, Becquerel discovered that uranium emitted ionizing radiation. The extraction by Pierre and Marie Curie of the more radioactive radium from uranium in the early years of the twentieth century and its application to the treatment of cancer shifted the chief interest to radium production. In the 1930s the discovery of the neutron and of artificial radioactivity stimulated research in a number of European laboratories which culminated in the demonstration of fission by Otto Frisch in January 1939. The new found use of uranium for the production of recoverable energy, and the creation of artificial radioelements in nuclear reactors, eliminated the radium industry. (author)

  18. Environmental Impacts and Health Aspects in the Mining Industry. A Comparative Study of the Mining and Extraction of Uranium, Copper and Gold

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Jenny-Ann; Randhem, Johan

    2008-07-01

    This thesis work has analysed environmental impacts and health aspects in the mining industry of copper, uranium and gold with the aim of determining the relative performance, in a given set of parameters, of the uranium mining industry. A selection of fifteen active mining operations in Australia, Canada, Namibia, South Africa, and the United States of America constitute the subject of this study. The project includes detailed background information about mineral extraction methods, the investigated minerals and the mining operations together with descriptions of the general main health hazards and environmental impacts connected to mining. The mineral operations are investigated in a cradle to gate analysis for the year of activity of 2007 using the economic value of the product at the gate as functional unit. Primary data has been collected from environmental reports, company web pages, national databases and through personal contact with company representatives. The subsequent analysis examines the collected data from a resource consumption, human health and ecological consequences point of view. Using the Life Cycle Impact Assessment methodology of characterisation, primary data of environmental loads have been converted to a synoptic set of environmental impacts. For radiation and tailings issues, a more general approach is used to address the problem. Based on the collected data and the investigated parameters, the results indicate a presumptive relative disadvantageous result for the uranium mining industry in terms of health aspects but an apparent favourable relative result in terms of environmental impacts. Given the prerequisites of this study, it is not feasible to draw any unambiguous conclusions. Inabilities to do this are mainly related to inadequate data availability from mine sites (especially in areas concerning tailings management), and difficulties concerned with the relative valuation of specific performance parameters, in particular radiation

  19. Environmental Impacts and Health Aspects in the Mining Industry. A Comparative Study of the Mining and Extraction of Uranium, Copper and Gold

    International Nuclear Information System (INIS)

    Nilsson, Jenny-Ann; Randhem, Johan

    2008-01-01

    This thesis work has analysed environmental impacts and health aspects in the mining industry of copper, uranium and gold with the aim of determining the relative performance, in a given set of parameters, of the uranium mining industry. A selection of fifteen active mining operations in Australia, Canada, Namibia, South Africa, and the United States of America constitute the subject of this study. The project includes detailed background information about mineral extraction methods, the investigated minerals and the mining operations together with descriptions of the general main health hazards and environmental impacts connected to mining. The mineral operations are investigated in a cradle to gate analysis for the year of activity of 2007 using the economic value of the product at the gate as functional unit. Primary data has been collected from environmental reports, company web pages, national databases and through personal contact with company representatives. The subsequent analysis examines the collected data from a resource consumption, human health and ecological consequences point of view. Using the Life Cycle Impact Assessment methodology of characterisation, primary data of environmental loads have been converted to a synoptic set of environmental impacts. For radiation and tailings issues, a more general approach is used to address the problem. Based on the collected data and the investigated parameters, the results indicate a presumptive relative disadvantageous result for the uranium mining industry in terms of health aspects but an apparent favourable relative result in terms of environmental impacts. Given the prerequisites of this study, it is not feasible to draw any unambiguous conclusions. Inabilities to do this are mainly related to inadequate data availability from mine sites (especially in areas concerning tailings management), and difficulties concerned with the relative valuation of specific performance parameters, in particular radiation

  20. Uranium production from phosphates

    International Nuclear Information System (INIS)

    Ketzinel, Z.; Folkman, Y.

    1979-05-01

    According to estimates of the world's uranium consumption, exploitation of most rich sources is expected by the 1980's. Forecasts show that the rate of uranium consumption will increase towards the end of the century. It is therefore desirable to exploit poor sources not yet in use. In the near future, the most reasonable source for developing uranium is phosphate rock. Uranium reserves in phosphates are estimated at a few million tons. Production of uranium from phosphates is as a by-product of phosphate rock processing and phosphoric acid production; it will then be possible to save the costs incurred in crushing and dissolving the rock when calculating uranium production costs. Estimates show that the U.S. wastes about 3,000 tons of uranium per annum in phosphoric acid based fertilisers. Studies have also been carried out in France, Yugoslavia and India. In Israel, during the 1950's, a small plant was operated in Haifa by 'Chemical and Phosphates'. Uranium processes have also been developed by linking with the extraction processes at Arad. Currently there is almost no activity on this subject because there are no large phosphoric acid plants which would enable production to take place on a reasonable scale. Discussions are taking place about the installation of a plant for phosphoric acid production utilising the 'wet process', producing 200 to 250,000 tons P 2 O 5 per annum. It is necessary to combine these facilities with uranium production plant. (author)

  1. Photochemical process of laboratory uranium wastes recovery

    International Nuclear Information System (INIS)

    Borges, O.N.; Barros, M.P. de.

    1984-01-01

    A method for uranium extraction in presence of various aquometallic ions, based on selective photo-reduction of uranium is studied. Some economical advantages in relation with others conventional processes are analysed. (M.J.C.) [pt

  2. Uranium exploration, mining and ore enrichment techniques

    International Nuclear Information System (INIS)

    Fuchs, H.D.; Wentzlau, D.

    1985-01-01

    The paper describes the different types of uranium deposits and their importance. It is shown that during the present depressed uranium market situation, mainly high grade deposits such as unconformity-related deposits can be mined economically. The different successive exploration steps are outlined including methods used for uranium. Uranium mining does not greatly differ from normal mining, but the uranium metallurgy needs its own specialized but already classic technology. Only a relative small amount of uranium can be expected from projects where uranium is produced by in situ leach methods or by extraction from phosphoric acid. A short summary of investment costs and operating costs is given for an average uranium mine. The last chapter deals with the definition of different reserve categories and outlines the uranium reserves of the western world including the uranium production (1983) and the expected uranium production capacity for 1985 and 1990. (orig.) [de

  3. Theory of kinetics and equilibrium of ion exchange-adsorption and mechanism of extracting uranium from sea-water with titanic gel

    International Nuclear Information System (INIS)

    Ai Hongtao

    1989-01-01

    An isothermal equation for ion exchange-adsorption is derived by mass action law. The equation can be used to sum up empirical and semiempirical formulas of the exchange adsorption, such as Gapon Equation, Sips Formula, Langmuir Equation and Freundlich Formula. In this paper, by adopting the ion exchange reaction to act as the determining step of the ion exchange adsorption kinetics, and exchange-adsorption kinetics equation is derived. It is verified by he results of a series of experiments in which uranium is extracted form enriched sea-water and natural sea-water with hydrous titanium oxide (titanic gel). This equation can be used to explain not only the results of test which have been applied to prove fast intraparticle diffusion of liquid film deffusion mechanism, but also test data which can be expalined by the co-controlling fast intraparticle and liquid film diffusion, and the kinetic data which can not be clarified by diffusion mechanism. It is proposed that the mechanism of the exchange adsorption of uranium from sea-water with titanic gel is a cationic exchange reaction. A method for calculating the quantity of exchange-adsorption at equilibrium is also given

  4. Depleted uranium

    International Nuclear Information System (INIS)

    Huffer, E.; Nifenecker, H.

    2001-02-01

    This document deals with the physical, chemical and radiological properties of the depleted uranium. What is the depleted uranium? Why do the military use depleted uranium and what are the risk for the health? (A.L.B.)

  5. Combination of solid phase extraction and dispersive liquid–liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination

    International Nuclear Information System (INIS)

    Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-01-01

    Graphical abstract: Pass the sample through the basic alumina column ⇒ elute retained uranium along with the cations ⇒ convert the uranium to its anionic benzoate complex ⇒ extract its ion pair with malachite green into small volume of chloroform by DLLME ⇒ measure its absorption at 621 nm using fiber optic-linear array detection spectrophotometry. -- Highlights: • By combination of SPE and DDLME a high preconcentration factor of 2500 was obtained. • Development of SPE-DDLME-Spectrophotometric method for det. of trace amounts of uranium. • Ultra trace amount of uranium in water samples was det. by the proposed method. • The detection limit of the proposed method is comparable to the most sensitive method. • The proposed method is a free interference spectrophotometric method for uranium det. -- Abstract: A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid–liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L −1 ) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid–liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L −1 , and a relative standard deviation of 4.1% (n = 6) at 400 ng L −1 were obtained. The method was

  6. Proposal to extract, process and export uranium from Jabiluka orebody No. 2. The Jabiluka proposal - Environmental assessment report

    International Nuclear Information System (INIS)

    1997-08-01

    This report assesses the environmental impact of a proposal by Energy Resources of Australia Ltd (ERA) to establish an underground uranium mine with associated infrastructure at the Jabiluka Prospect, approximately 20 km north of Jabiru in the Northern Territory (NT). In accordance with the Environment Protection (Impact of Proposals) Act 1974 (EPIP Act) the Minister for Resources and Energy designated ERA as proponent in relation to prospective decisions to grant approvals for uranium exports from the Jabiluka mine under Regulation 11 of the Customs (Prohibited Exports) Regulations. The report reviews the draft Environmental Impact Statement (draft EIS), public comments on the draft EIS, and the proponent's responses to these comments in the Supplement to the draft EIS (the draft EIS plus the Supplement constitutes the final EIS). It also relies on information, comments and advice provided by areas within Environment Australia, other relevant Commonwealth agencies, Northern Territory Department of Lands, Planning and Environment (NTDLPE)(through the joint assessment process) and previous studies undertaken in the region

  7. Proposal to extract, process and export uranium from Jabiluka orebody No. 2. The Jabiluka proposal - Environmental assessment report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    This report assesses the environmental impact of a proposal by Energy Resources of Australia Ltd (ERA) to establish an underground uranium mine with associated infrastructure at the Jabiluka Prospect, approximately 20 km north of Jabiru in the Northern Territory (NT). In accordance with the Environment Protection (Impact of Proposals) Act 1974 (EPIP Act) the Minister for Resources and Energy designated ERA as proponent in relation to prospective decisions to grant approvals for uranium exports from the Jabiluka mine under Regulation 11 of the Customs (Prohibited Exports) Regulations. The report reviews the draft Environmental Impact Statement (draft EIS), public comments on the draft EIS, and the proponent`s responses to these comments in the Supplement to the draft EIS (the draft EIS plus the Supplement constitutes the final EIS). It also relies on information, comments and advice provided by areas within Environment Australia, other relevant Commonwealth agencies, Northern Territory Department of Lands, Planning and Environment (NTDLPE)(through the joint assessment process) and previous studies undertaken in the region

  8. Extraction process

    International Nuclear Information System (INIS)

    Rendall, J.S.; Cahalan, M.J.

    1979-01-01

    A process is described for extracting at least two desired constituents from a mineral, using a liquid reagent which produces the constituents, or compounds thereof, in separable form and independently extracting those constituents, or compounds. The process is especially valuable for the extraction of phosphoric acid and metal values from acidulated phosphate rock, the slurry being contacted with selective extractants for phosphoric acid and metal (e.g. uranium) values. In an example, uranium values are oxidized to uranyl form and extracted using an ion exchange resin. (U.K.)

  9. Uranium complex recycling method of purifying uranium liquors

    International Nuclear Information System (INIS)

    Elikan, L.; Lyon, W.L.; Sundar, P.S.

    1976-01-01

    Uranium is separated from contaminating cations in an aqueous liquor containing uranyl ions. The liquor is mixed with sufficient recycled uranium complex to raise the weight ratio of uranium to said cations preferably to at least about three. The liquor is then extracted with at least enough non-interfering, water-immiscible, organic solvent to theoretically extract about all of the uranium in the liquor. The organic solvent contains a reagent which reacts with the uranyl ions to form a complex soluble in the solvent. If the aqueous liquor is acidic, the organic solvent is then scrubbed with water. The organic solvent is stripped with a solution containing at least enough ammonium carbonate to precipitate the uranium complex. A portion of the uranium complex is recycled and the remainder can be collected and calcined to produce U 3 O 8 or UO 2

  10. U for uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The Beisa Mine is unique in South Africa - it is the only underground mine with uranium as its main product and gold as a by-product. At the rate of 1,2 Mt/a, the life of Beisa is estimated on 26 years. Beisa's metallurgical plant is designed to handle initially a monthly throughput of 100 000t of ore, from which uranium, gold and silver will be extracted

  11. Recovering uranium from phosphoric acid

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Wet-process phosphoric acid contains a significant amount of uranium. This uranium totals more than 1,500 tons/yr in current U.S. acid output--and projections put the uranium level at 8,000 tons/yr in the year 2000. Since the phosphoric acid is a major raw material for fertilizers, uranium finds its way into those products and is effectively lost as a resource, while adding to the amount of radioactive material that can contaminate the food chain. So, resource-conservation and environmental considerations both make recovery of the uranium from phosphoric acid desirable. This paper describes the newly developed process for recovering uranium from phosphoric acid by using solvent-extraction technique. After many extractants had been tested, the researchers eventually selected the combination of di (2-ethylhexyl) phosphoric acid (DEPA) and trioctylphosphine oxide (TOPO) as the most suitable. The flowscheme of the process is included

  12. Uranium conversion

    International Nuclear Information System (INIS)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

    2006-03-01

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

  13. Considerations in the extraction of uranium from a fresh-water aquifer - Miocene Oakville Sandstone, south Texas

    International Nuclear Information System (INIS)

    Henry, C.D.; Galloway, W.E.; Smith, G.E.

    1982-01-01

    The Miocene Oakville Sandstone is a major aquifer and uranium host beneath the Texas Coastal Plain. Present and future uranium mining by either surface or in situ methods could affect the availability and quality of Oakville ground water unless the mining is designed properly. Possible effects of mining, potential natural mitigation of these effects, and approaches to minimizing the impact of mining on the aquifer system are discussed. Both solution and surface mining may affect the availability of ground water by altering recharge characteristics and permeability. Because the volume of the aquifer affected by mining is small compared with its total volume, availability of Oakville ground water will probably not be reduced significantly, except in wells immediately adjacent to a mine. Mining may affect the quality of ground water by introducing chemicals that are not indigenous to the aquifer or by inducing chemical reactions that do not occur naturally or that occur at much slower rates. Most mining companies no longer use concentrated, ammonium-based leaches because of known problems in restoring water to its original chemistry. Natural and induced release of trace elements such as molybdenum is known to occur, but the geochemical controls on mobility and potential mitigating reactions in the aquifer are poorly understood. Because the affected aquifer volume is small, any deterioration of water quality will probably be localized. Observations and recommendations are presented on: regional and local baseline studies, determination of aquifer sensitivity, methods and goals of monitoring during and after mining, and need for research on poorly understood aspects of mining impact. Such impacts include chemical reactions and processes that affect the long-term release of trace elements

  14. Vaal Reefs South uranium plant

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    The Vaal Reefs mining complex, part of the Anglo American Corporation, is the largest gold and uranium producing complex in the world, being South Africa's principal producer, accounting for about a quarter of the country's uranium production. Vaal Reefs South uranium plant in the Orkney district was recently officially opened by Dr AJA Roux, the retiring president of the Atomic Energy Board and chairman of the Uranium Enrichment Corporation and will increase the country's uranium production. In the field of technology, and particularly processing technology, South Africa has shown the world unprecedented technology achievement in the field of uranium extraction from low grade ores and the development of the unique uranium enrichment process. New technical innovations that have been incorporated in this new plant are discussed

  15. Direct extraction of uranium and plutonium from oxide fuel using TBP-HNO3 complex for super-DIREX process

    International Nuclear Information System (INIS)

    Miura, S.; Kamiya, M.; Nomura, K.; Koyama, T.; Ogum, S.; Shimada, T.; Mori, Y.; Enokida, Y.

    2004-01-01

    Super-DIREX is a new reprocessing method which has high economical efficiency. Experimental study of this process was started on the direct extraction of U and Pu from irradiated MOX fuel by the supercritical carbon dioxide (SFCO 2 ) containing TBP-HNO 3 complex. This report describes direct extraction of U and Pu with TBP-HNO 3 complex at atmospheric pressure, as the first test for irradiated fuel, in order to investigate the applicability of SFCO 2 containing TBP-HNO 3 complex. In this test, dependency on dissolution temperature, Pu content, fuel/ TBP-HNO 3 complex ratio and effect of voloxidation were investigated. From these results, TBP-HNO 3 complex was found to be effective in the respect of the recovery of U and Pu. The number of the process step in dissolution and co-extraction is small, and amount of waste can be reduced. It is applicable to the direct extraction in Super-DIREX. (authors)

  16. Uranium exploration

    International Nuclear Information System (INIS)

    De Voto, R.H.

    1984-01-01

    This paper is a review of the methodology and technology that are currently being used in varying degrees in uranium exploration activities worldwide. Since uranium is ubiquitous and occurs in trace amounts (0.2 to 5 ppm) in virtually all rocks of the crust of the earth, exploration for uranium is essentially the search of geologic environments in which geologic processes have produced unusual concentrations of uranium. Since the level of concentration of uranium of economic interest is dependent on the present and future price of uranium, it is appropriate here to review briefly the economic realities of uranium-fueled power generation. (author)

  17. Electrolytic recovery of uranium oxides

    International Nuclear Information System (INIS)

    Gurr, W.R.

    1979-01-01

    A method is described for extracting uranium oxide from a solution of one or more uranium compounds, e.g. leach liquors, comprising subjecting the solution to electrolysis utilizing a high current density, e.g. 500 to 4000 amp/m 2 , whereby uranium oxide is formed at the cathode and is recovered. The method is particularly suited to a continuous process using a rotating cathode cell. (author)

  18. Liquid membrane process for uranium recovery

    International Nuclear Information System (INIS)

    Valint, P.L. Jr.

    1982-01-01

    An improved liquid membrane emulsion extraction process for recovering uranium from a WPPA feed solution containing uranyl cations wherein said feed is contacted with a water-in-oil emulsion which extracts and captures the uranium in the interior aqueous phase thereof, wherein the improvement comprises the presence of an alkane diphosphonic acid uranium complexing agent in the interior phase of the emulsion. This improvement results in greater extraction efficiency

  19. Determination of uranium in urine by fluorometry

    International Nuclear Information System (INIS)

    Afsar, M.; Aziz, A.; Mubarak, M.A.

    1978-01-01

    The report describes fluorometric determination of traces of uranium in the urine of mine workers and persons handling uranium. After preliminary treatment uranium is extracted by solvent extraction with TBP:MIBK mixtures. An aliquot of the extracted solution is fused with high carbonate flux at 650 0 C in platinum dishes. The fluorescence of fused sample is measured using a fluorometer. Various fusion parameters are discussed. The procedure for the operation and calibration of fluorometer is also described

  20. Irradiated uranium reprocessing, Final report I-VI, Part V - report on development of laboratory extraction procedure for separation of U, Pu, and FP on the tracer level; Prerada ozracenog urana. Zavrani izvestaj - I-VI, V Deo - Izvestaj o razradi laboratorijskog procesa ekstrakcije za odvajanje U, Pu i FP na nivou obelezavaca

    Energy Technology Data Exchange (ETDEWEB)

    Gal, I [Institute of Nuclear Sciences Boris Kidric, Odeljenje za eksploataciju nuklearnog goriva, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    A laboratory extraction procedure was developed for separation of uranium, plutonium and fission products from the nitric solution. The procedure would be applied for uranium and spent fuel from the RA reactor in Vinca. This is a Purex type of procedure adapted for laboratory purposes. Experimental data are obtained by using syntetic nitric uranium solutions with Pu and fission products additions as tracers. A device for completing the process was constructed.

  1. Diluent and extractant effects on the enthalpy of extraction of uranium(VI) and americium(III) nitrates by trialkyl phosphates

    International Nuclear Information System (INIS)

    Srinivasan, T.G.; Vasudeva Rao, P.R.; Sood, D.D.

    1998-01-01

    The effect of various diluents such as n-hexane, n-heptane n-octane, isooctane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-hexadecane, cyclohexane, benzene, toluene, p-xylene, mesitylene and o-dichlorobenzene on the enthalpy of extraction of uranyl nitrate by tri-n-amyl phosphate (TAP) over the temperature range 283 K--333 K has been studied. The results indicate that the enthalpy of extraction does not vary significantly with the diluents studied. Also enthalpies of extraction of uranyl nitrate and americium(III) nitrate by neutral organo phosphorous extractants such as tri-n-butyl phosphate (TBP), tri-n-amyl phosphate (TAP), tri-sec-butyl phosphate (TsBP), tri-isoamyl phosphate (TiAP) and tri-n-hexyl phosphate (THP) have been studied. An attempt has been made to explain the trends, on the basis of the nature of the solvate formed and the different terms which contribute to the overall enthalpy change

  2. Uranium, Plutonium and Neptunium Co-recovery with Irradiated Fast Reactor MOX Fuel by Single Cycle Extraction Process

    Energy Technology Data Exchange (ETDEWEB)

    Masaumi Nakahara; Yuichi Sano; Kazunori Nomura; Tadahiro Washiya; Jun Komaki [Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki, 319-1194 (Japan)

    2008-07-01

    The behavior of Np in single cycle extraction processes using tri-n-butylphosphate (TBP) as an extractant for U, Pu and Np co-recovery was investigated as a part of NEXT (New Extraction System for Transuranium) process. Two approaches for Np co-recovery with U and Pu were carried out with irradiated MOX fuel from fast reactor 'JOYO'; one was the counter current experiment using a feed solution with a high HNO{sub 3} concentration and the other used a scrubbing solution with a high HNO{sub 3} concentration. Experimental results showed that the leakage of Np to the raffinate were 0.986 % and 5.96 % under the condition of high HNO{sub 3} concentration in the feed solution and scrubbing solution, respectively. The simulation results based on these experiments indicated that most of Np could be extracted and co-recovered with U and Pu, just by increasing HNO{sub 3} concentrations in the feed and scrubbing solution on the single cycle extraction process. (authors)

  3. Extraction and purification of yellow cake

    International Nuclear Information System (INIS)

    Yousif, E.H.

    2006-01-01

    This dissertation has reviewed current studies on production and purification of yellow cake from uranium ores by both acid and alkaline leaching processes. It comprises three chapters, the first one deal with uranium minerals, uranium deposits, geology of uranium and uranium isotopes. The second chapter covers mining and milling methods, uranium leaching chemistry, precipitation, and purification of uranium concentrate by solvent extraction and possible impurities that commonly interfered with yellow cake. The last chapter presented ongoing literature review.(Author)

  4. Uranium hexafluoride. Bromine spectrophotometric determination

    International Nuclear Information System (INIS)

    Anon.

    Bromine determination in hydrolized uranium hexafluoride by reduction of bromates by ferrous sulfate, oxidation of bromides by potassium permanganate to give bromine which is extracted into carbon tetrachloride and transformed in eosine for spectrophotometry at 510 nm. The method is suitable for determining 5 to 150 ppm with respect to uranium [fr

  5. Successful trials on pressure leaching of uranium

    International Nuclear Information System (INIS)

    Pendreigh, R.

    1978-01-01

    High pressure leaching can increase uranium extraction from some low grade ores by ten per cent, and Anglo American Corporation's eighteen months of pilot plant tests point the way to commercial application. Interest in pressure leaching of uranium has been renewed with the recent increase in uranium and gold prices and costs of reagents

  6. Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.

    Science.gov (United States)

    Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

    2013-12-15

    A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Uranium chemistry: significant advances

    International Nuclear Information System (INIS)

    Mazzanti, M.

    2011-01-01

    The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

  8. Uranium and environment in Kazakstan

    International Nuclear Information System (INIS)

    Fyodorov, G.; Bayadilov, E.; Zhelnov, V.; Akhmetov, M.; Abakumov, A.

    1997-01-01

    Kazakstan's data on uranium as a state report has been included for the first time in the Red Book. Therefore the report contains two large themes presented in Suggested Topics for Papers: Country report, based on the 1995 NEA/IAEA Red Book Questionnaire and environmental impact regulations. Kazakstan is considered as one of the world leaders on uranium supply. In Kazakstan there are many well known types of deposits but the main one is the sandstone-rollfront type. That type is represented by the group of deposits of the Syr-Darya uranium ore province. Deposits of that type include that main part of uranium ore of the Republic of Kazakstan and supply almost all of its uranium mining. At the large three enterprises the uranium is extracted by underground leaching. The mining method of uranium extraction is stopped. Because of the poor development of nuclear energy, Kazakstan's need for uranium is not very high. Presence of a large amount of cheap and technological uranium ores allow the Republic to export uranium. There are plans to increase uranium mining and perhaps to establish new mining facilities including joint-ventures. More than 50 uranium deposits are known in Kazakstan. During prospecting and exploitation of these deposits a large amount of rad wastes in the form of ore dumps and tailings were generated. They have a substantial influence on the environment. Moreover, near the sandstone-rollfront type uranium deposits the large amount of underground water has been contaminated by radionuclides. Special investigation of this phenomenon is necessary. In Kazakstan there are the rad waste disposal conception and contaminated earth recultivation regulations. At present ''The Rad Wastes Management Law'' is submitted for approval. (author). 2 figs

  9. Uranium hexafluoride purification

    International Nuclear Information System (INIS)

    Araujo, Eneas F. de

    1986-01-01

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF 6 -HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF 6 -HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  10. Heap leaching for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    Denison Mines Ltd. is using two bacterial leaching processes to combat the high cost of extracting uranium from low grade ore in thin reefs. Both processes use thiobacillus ferro-oxidans, a bacterium that employs the oxidation of ferrous iron and sulphur as its source of energy for growth. The first method is flood leaching, in which ore is subjected to successive flood, drain and rest cycles. The second, trickle leaching, uses sprinklers to douse the broken muck continuously with leaching solution. In areas where grades are too low to justify the expense of hauling the ore to the surface, the company is using this biological process underground to recover uranium. In 1987 Denison recovered 840 000 lb of uranium through bacterial heap leaching. It plans to have biological in-place leaching contribute 25% of the total uranium production by 1990. (fig.)

  11. Evaluation of uranium and arsenic retention by soil from a low level radioactive waste management site using sequential extraction

    International Nuclear Information System (INIS)

    Evans, G.J.; Dhoum, R.T.

    1998-01-01

    The European Communities Bureau of Reference (BCR) and Chunguo sequential extraction procedures were employed to evaluate the retention of U and As by a soil contaminated with low level radioactive waste. Modifications were made to both procedures to optimize the measurement of soil and extractant samples using epithermal neutron activation analysis. Based on the BCR procedure, approximately 20% of the U appeared to be bound to the carbonate fraction, 10% to the mineral oxide fraction and 20% to the organic fraction. In the case of As, the majority was strongly bound in the residue fraction. The results obtained with the Chunguo procedure supported these conclusions to some extent, in that the majority of the U and As was found to be strongly bound to the soil in a manner consistent with its presence in the residue fraction. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Direct dissolution and supercritical fluid extraction of uranium from UO2 powder, granule, green pellet and sintered pellet

    International Nuclear Information System (INIS)

    Rao, Ankita; Kumar, Pradeep; Ramakumar, K.L.

    2009-01-01

    In the present work, direct dissolution and extraction of UO 2 from the solid rejects various stages of fuel fabrication viz. powder granules green pellet and, sintered pellet has been studied. Powder and granules could be easily dissolved in TBP-HNO 3 complex at 50 deg C., whereas in case of green and sintered pellets at elevated temperature at raised to 80 deg C in TBP-HNO 3 complex. With supercritical (SC) CO 2 alone the efficiency was ∼70%. But with SC CO 2 +2.5% TBP, the efficiency was ∼95% for powder and granules, and ∼60% for green and sintered pellets. Nearly complete extraction (∼99%) was achievable for SC CO 2 + 2.5 % TTA in all cases. The method has distinct advantage of elimination of acid usage and minimization of liquid waste generation. (author)

  13. The rapid determination of 210Po in uranium ores by TRPO extraction-α inner-scintillation method

    International Nuclear Information System (INIS)

    Zhu Tianxia

    1993-02-01

    Ores are treated with HF to remove Si, then 210 Po is leached out by HCl + H 2 O 2 solution. The solution is extracted by TRPO and re-extracted with 5% H 2 C 2 O 4 solution. Ti(SO 4 ) 2 is added to the re-extraction solution and the pH value of solution is adjusted with NaOH, then the solution is evenly mixed with ZnS(Ag) and filtered. After the filter has dried the activity is measured by alpha counting of inner-scintillation method. When the sample has prepared the measurement can immediately carry out. The measurement are not interfered by α-radiators from 238 U, 235 U and 2 '3'2Th as well as daughters of Pb and Bi. The recovery of whole chemical process is 98%. The detecting efficiency is (95+-1)%. The precision is better than +- 4%. The α-4π detect in limitation depends on the background counting of Ti(SO 4 ) 2 . For the CP reagent, the value is (7 ∼ 23) x 10 -3 Bq/6 mg Ti 4+ . It can be reduced greatly after purification. The analytical period is 12 samples/8 h (activity of 210 Po ≥ 1 Bq/g

  14. Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass.

    Science.gov (United States)

    Duquène, L; Vandenhove, H; Tack, F; Van Hees, M; Wannijn, J

    2010-02-01

    The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C(DGT)) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO(2)(2+), uranyl carbonate complexes and UO(2)PO(4)(-). The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants. Copyright 2009 Elsevier Ltd. All rights reserved.

  15. Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass

    Energy Technology Data Exchange (ETDEWEB)

    Duquene, L. [SCK-CEN, Biosphere Impact Studies, Boeretang 200, B-2400 Mol (Belgium); Vandenhove, H., E-mail: hvandenh@sckcen.b [SCK-CEN, Biosphere Impact Studies, Boeretang 200, B-2400 Mol (Belgium); Tack, F. [Ghent University, Laboratory for Analytical Chemistry and Applied Ecochemistry, Coupure Links 653, B-9000 Gent (Belgium); Van Hees, M.; Wannijn, J. [SCK-CEN, Biosphere Impact Studies, Boeretang 200, B-2400 Mol (Belgium)

    2010-02-15

    The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C{sub DGT}) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO{sub 2}{sup 2+}, uranyl carbonate complexes and UO{sub 2}PO{sub 4}{sup -}. The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants.

  16. Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass

    International Nuclear Information System (INIS)

    Duquene, L.; Vandenhove, H.; Tack, F.; Van Hees, M.; Wannijn, J.

    2010-01-01

    The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C DGT ) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO 2 2+ , uranyl carbonate complexes and UO 2 PO 4 - . The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants.

  17. Solvent extraction of uranium(VI), plutonium(VI) and americium(III) with HTTA/HPMBP using mono- and bi-functional neutral donors. Synergism and thermodynamics

    International Nuclear Information System (INIS)

    Pai, S.A.; Lohithakshan, K.V.; Mithapara, P.D.; Aggarwal, S.K.

    2000-01-01

    Synergistic extraction of hexavalent uranium and plutonium as well as trivalent americium was studied in HNO 3 with thenoyl, trifluoro-acetone (HTTA)/1-phenyl, 3-methyl, 4-benzoyl pyrazolone-5 (HPMBP) in combination with neutral donors viz. DPSO, TBP, TOPO (mono-functional) and DBDECMP, DHDECMP, CMPO (bi-functional) with wide basicity range using benzene as diluent. A linear correlation was observed when the equilibrium constant log Ks for the organic phase synergistic reaction of both U(VI) and Pu(VI) with either of the chelating agents HTTA or HPMBP was plotted vs. the basicity (log Kh) of the donor (both mono- and bi-functional) indicating bi-functional donors also behave as mono-functional. This was supported by the thermodynamic data (ΔG 0 , ΔH 0 , ΔS 0 ) obtained for these systems. The organic phase adduct formation reactions were identified for the above systems from the thermodynamic data. In the Am(III) HTTA system log K s values of bi-functional donors were found to be very high and deviate from the linear plot (log K s vs. log K h ) obtained for mono-functional donors, indicating that they function as bi-functional for the Am(III)/HTTA) system studied. This was supported by high +ve ΔS 0 values obtained for this system. (author)

  18. Health impact assessment resulting from water pollution by the activities of extraction and treatment of uranium in the department of Haute-Vienne

    International Nuclear Information System (INIS)

    Grenetier, Nicolas

    2002-01-01

    From the middle to the end of the twentieth century, several thousands tons of uranium have been extracted from the ground of the French department of Haute-Vienne. These activities have not been without any environmental consequences. Water is an environmental compartment particularly vulnerable because several polluting factors may release radionuclides from 238 U chain a long time after the end of the mining activities. It has been shown that water used for drinking water fabrication for the City of Limoges, 140 000 inhabitants, and for a group of 22 communes with 20 000 inhabitants and leisure water of Saint-Pardoux lake have activities which are unusually high. A health risk quantitative assessment has been carried out. The results show for radiological risk that 226 Ra is, in the most realistic hypothesis, the main responsible for the annual effective dose; moreover, the annual effective dose are lower than the radioprotection standards and the WHO's recommendations of 0.1 mSv per year in drinking water. The results also show that it would not be pertinent to carry out an epidemiological study because of a lack of statistical power. (author)

  19. Uranium recovery from mine water

    International Nuclear Information System (INIS)

    Sarkar, K.M.

    1984-01-01

    In many plant trials it has been proven that very small amounts (10 to 20 ppm) of uranium dissolved in mine water can be effectively recovered by the use of ion exchange resins and this uranium recovery has many advantages. In this paper an economic analysis at different levels of uranium contamination and at different market prices of uranium are described. For this study an operating mine-mill complex with a sulphuric acid leach circuit, followed by solvent extraction (SX) process, is considered, where contaminated mine water is available in excess of process requirements. It is further assumed that the sulphuric acid eluant containing uranium would be mixed with the mill pregnant liquor stream that proceeds to the SX plant for final uranium recovery

  20. Method for determining microamounts of uranium in solutions from copper ores, by liquid-liquid extraction and spectrophotometry with arsenazo III.; Metodo para determinar microcantidades de uranio en disoluciones de minerales de cobre, por extraccion liquido-liquido y espectrofotometria con arsenazo III

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, B.

    1972-07-01

    A spectrophotometric method is described for determining small amounts of uranium in aqueous solutions from copper ores. Uranium is quantitatively separated in a single extraction by a solution of tri-n-octylphosphine oxide in benzene, using ethylendiaminetetracetic acid and sodium fluoride as complexing agents, for improving the selectivity of the procedure. An aliquot of the extract is diluted with a hydrocolloidal solution of arsenazo III. Optical density is measured at 650 nm. (Author) 3 refs.

  1. Feasibility studies on electrochemical separation and recovery of uranium by using domestic low grade uranium resources

    International Nuclear Information System (INIS)

    Oh, Won Zin; Jung, Chong Hun; Lee, Kune Woo; Won, Hui Jun; Choi, Wang Kyu; Kim, Gye Nam; Lee, Yu Ri; Lee, Joong Moung

    2005-12-01

    The up-to-date electrochemical uranium separation technology has been developed for uranium sludge waste treatment funded by a long term national nuclear technology development program. The objective of the studies is to examine applicability of the uranium separation technology to making use of the low grade uranium resources in the country. State of the arts of uranium separation and recovery from the low grade national uranium resources. - The amount of the high grade uranium resources(0.1 % U 3 O 8 contents) in the world is 1,750,000MTU and that of the low grade uranium resources(0.04 % U 3 O 8 contents) in the country is 340,000MTU. - The world uranium price will be increase to more than 30$/l0b in 10 years, so that the low grade uranium in the country become worth while to recover. - The conventional uranium recovery technologies are based on both acidic - The ACF electrochemical uranium separation technology is the state of the art technology in the world and the adsorption capability of 690 mgU/g is several ten times higher than that of a conventional zeolite and the uranium stripping efficiency by desorption is more than 99%. So, this technology is expected to replace the existing solvent extraction technology. Feasibility of the ACF electrochemical uranium separation technology as an uranium recovery method. Lab scale demonstration of uranium separation and recovery technologies have been carried out by using an ACF electrochemical method

  2. Separation of thorium and uranium by liquid-liquid extraction from mixed aqueous nitric acidic-methanolic solutions

    International Nuclear Information System (INIS)

    Schmid, E.R.; Kenndler, E.

    1976-01-01

    A method is described for the separation of Th and U from each other and from other elements, usually occuring in minerals, by liquid-liquid extraction with Aliquat Nitrate (tricaprylmethyl ammoniumnitrate, 6 vol%) in benzene from a mixed solution of 2.5 M HNO 3 and methanol (1:1 volume ratio). Permissible upper concentration ratios of interfering elements, such as Li, Na, K, Mg, Ca, Al, Cu, Co(II), Fe(III), Mn(II), Ti(IV), La(III), U(VI), Cl - , ClO 4 - , SO 4 2- , PO 4 3- , have been determined. Following the separation, Th has been determined by spectrophotometry using Thorin, and U by fluorometry. Results for yield under varying conditions, together with elemental concentrations in the ppm range for U and Th in minerals, are given. (B.T.)

  3. EXTRACT

    DEFF Research Database (Denmark)

    Pafilis, Evangelos; Buttigieg, Pier Luigi; Ferrell, Barbra

    2016-01-01

    The microbial and molecular ecology research communities have made substantial progress on developing standards for annotating samples with environment metadata. However, sample manual annotation is a highly labor intensive process and requires familiarity with the terminologies used. We have the...... and text-mining-assisted curation revealed that EXTRACT speeds up annotation by 15-25% and helps curators to detect terms that would otherwise have been missed.Database URL: https://extract.hcmr.gr/......., organism, tissue and disease terms. The evaluators in the BioCreative V Interactive Annotation Task found the system to be intuitive, useful, well documented and sufficiently accurate to be helpful in spotting relevant text passages and extracting organism and environment terms. Comparison of fully manual...

  4. Uranium production in Sweden

    International Nuclear Information System (INIS)

    Bergh, S.

    1994-01-01

    The history of uranium production in Sweden is reviewed in the article. The World War II led to an exploitation of the Swedish alum shale on a large scale. In the last phase of the war it also became obvious that the shale might be used for energy production of quite another kind than oil. In 1947 AB Atom energy was founded, an enterprise with one of its purposes to extract uranium for peaceful use. A plant with a yearly capacity of 120 tons of uranium was erected at Ranstad and ready for production by 1965. From the start in Ranstad and for many years to come there was hardly any interest in an immediate large uranium production. It was decided to use the plant for studies on its more effective exploitation in case of an expansion in the future, bearing in mind the reactor programme. In the course of time economical reasons began to speak against the project. The shale seemed to have a future neither as oil nor as uranium resource. The complete termination of the work on uranium production from shale occurred in 1989

  5. South African uranium industry plans for expansion

    International Nuclear Information System (INIS)

    James, H.E.; Boydell, D.W.; Simonsen, H.A.

    1978-01-01

    Resources and production of uranium in South Africa are discussed. The cost of mining and extraction from gold ores is considered. An outline is presented of the extraction and recovery of uranium and of new developments in sorting, milling, and preconcentration. (U.K.)

  6. Uranium fluorides analysis. Titanium spectrophotometric determination

    International Nuclear Information System (INIS)

    Anon.

    Titanium determination in uranium hexafluoride in the range 0.7 to 100 microgrammes after transformation of uranium fluoride in sulfate. Titanium is separated by extraction with N-benzoylphenylhydroxylamine, reextracted by hydrochloric-hydrofluoric acid. The complex titanium-N-benzoylphenylhydroxylamine is extracted by chloroform. Spectrophotometric determination at 400 nm [fr

  7. An approach using centrifugation for the extraction of the soil solution and its usefulness in studies of radionuclide speciation in soils - Approach using centrifugation for extraction of soil solution and its study for uranium speciation

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Adriana S. [CAPES Foundation, Ministry of Education of Brazil, 70040-020, Brasilia, Brazil, Proc.BEX 1958/13-5 (Brazil); Lozano, J.C.; Prieto, C. [Universidad de Salamanca, 37008, Salamanca (Spain); Blanco Rodriguez, P.; Vera Tome, F. [Universidad de Extremadura, 06006, Badajoz (Spain)

    2014-07-01

    The centrifugation technique is tested as a methodology for extraction of soil solution, for further characterization, in order to elucidate its contribution to the speciation of radionuclides, particularly uranium, in radioactively contaminated soils, as well as the determination of its availability for vegetation. Centrifugation of a previously saturated soil core provides the soil solution with a specific origin inside the soil sample. In such way that the different soil solution origin, associate to the effective pressure applied to the soil core, will reflect different distribution coefficients which affect the radionuclide availability definition. Speciation of radionuclides in the soil solution can be also conditioned by this water origin. The development of this methodology relating to technical challenges faces materials suitable for the centrifugation process, both in terms of mechanical properties and chemical inertness. This paper reports the preparation of ceramic pellets of perlite produced with the intention of replacing glass pellets, used inserts in support to soils coupled with centrifuges. The characterization of porosity and the test of its chemical inertness and mechanical strength to the centrifugation process have been performed. Porosity characterization is required to control the saturation gradient, which conditions the flow of water from the soil. Its mechanical adequacy was tested by subjecting the pellets to the centrifugation process and assessing its integrity end. Chemical inertia was measured by placing the tablets in aqueous solutions of known composition and then evaluating the presence or absence of elements in this solution, after on time of contact between them. (authors)

  8. Uranium accompanying recovery from copper ores

    International Nuclear Information System (INIS)

    Golynko, Z.Sh.; Laskorin, B.N.

    1981-01-01

    In the search for new raw material sources for nuclear power engineering a review of the technique of uranium accompaning recovery from copper ores reprocessing products in some countries is presented. In the USA a sorption method of uranium extraction by means of strongly basic ion exchange resins from solutions upon copper case- hardening with subsequent extraction from eluates by solutions of tertiary amines is realized. Elution is realized with sulphuric acid. In South Africa an extraction reprocessing of gravitational concentrate extracted from copper sulphide flotation tailings is organized. In India the uranium extraction from copper ores flotation enrichment tailings is organized on a commerical scale. Presented are data on the scale of uranium recovery, various conditions of its recovery as well as block diagrams of the processes. It is shown that copper ores become an additional source of uranium recovery [ru

  9. Uranium production and the environment in Kazakhstan

    International Nuclear Information System (INIS)

    Fyodorov, G.V.

    2002-01-01

    The production of uranium from open-pit and underground mines in Kazakhstan has terminated. Currently, uranium is extracted in Kazakhstan only by the In Situ Leaching (ISL) method. This method has a number of economical and ecological advantages. During a short period in the 70s-80s, Kazakhstan created a firm basis for developing uranium extraction by the ISL method. Now more than half of the world's uranium reserves amenable to the ISL method are located in Kazakhstan. By 2005, a significant increase in uranium production is planned. Thereby, Kazakhstan has the ability to grow into a world leader in uranium extraction through a lower cost and low environmental impact operations using the ISL method. (author)

  10. Kvanefjeld uranium project

    International Nuclear Information System (INIS)

    Erlendsson, G.; Jensen, J.; Kofoed, S.; Paulsen, J.L.

    1983-11-01

    The draft uranium project ''Kvanefjeld'' describes the establishment and operation of an industrial plant for exploiting the uranium deposit at Kvanefjeld. The draft project is part of the overall pre-feasibility project and is based on its results. The draft project includes two alternative locations for the processing plant and the tailings deposit plant. The ore reserve is estimated at 56 million tons with an average content of 365 PPM. The mine will be established as an open pit, with a slope angle of 55deg. Conventional techniques are used in drilling, blasting and handling the ore. Waste rock with no uranium content will be disposed of in two ponds near the mine. The waste rock volume is estimated at 80 million tons. A processing plant for extracting uranium from the ore will be established. The technical layout of the plant is based on the extraction experiments performed at Risoe from 1981-83. Yearly capacity is 4.2 million tons of ore. Electrical energy will be supplied from a hydroelectric station to be built at Johan Dahl Land. Thermal energy (steam/heat) will be supplied from a coal-fired district heating plant to be built in connection with the processing plant. Expected power consumption is estimated at 225 GWh/year. Heat consumption is of the same order. In the third year the plant is expected to operate at full capacity. Operating costs will be Dkr. 121/ton of ore from years 1 through 7. Consumption of chemicals will be reduced from the 7th year, and operating costs will consequently drop to Dkr. 115/ton of ore. Calculations show that industrial extraction of the uranium deposit in Kvanefjeld is economically advantageous. In addition, the economy of the project is expected to improve by extracting byproducts from the ore. (EG)

  11. Uranium market

    International Nuclear Information System (INIS)

    Rubini, L.A.; Asem, M.A.D.

    1990-01-01

    The historical development of the uranium market is present in two periods: The initial period 1947-1970 and from 1970 onwards, with the establishment of a commercial market. The world uranium requirements are derived from the corresponding forecast of nuclear generating capacity, with, particular emphasis to the brazilian requirements. The forecast of uranium production until the year 2000 is presented considering existing inventories and the already committed demand. The balance between production and requirements is analysed. Finally the types of contracts currently being used and the development of uranium prices in the world market are considered. (author)

  12. Uranium enrichment

    International Nuclear Information System (INIS)

    1990-01-01

    This report looks at the following issues: How much Soviet uranium ore and enriched uranium are imported into the United States and what is the extent to which utilities flag swap to disguise these purchases? What are the U.S.S.R.'s enriched uranium trading practices? To what extent are utilities required to return used fuel to the Soviet Union as part of the enriched uranium sales agreement? Why have U.S. utilities ended their contracts to buy enrichment services from DOE?

  13. The Kintyre uranium project

    International Nuclear Information System (INIS)

    Larson, B.

    1997-01-01

    The Kintyre Uranium Project is being developed by Canning Resources Pty Ltd, a subsidiary of Rio Tinto (formerly CRA). The work on the project includes the planning and management of a number of background environmental studies. The company has also commissioned studies by external consultants into process technologies, mining strategies and techniques for extracting the uranium ore from the waste rock. In addition, Canning Resources has made a detailed assessment of the worldwide market potential for Australian uranium in the late 1990s and into the 21st century. The most significant factor affecting the future of this project is the current product price. This price is insufficient to justify the necessary investment to bring this project into production

  14. Uranium ore processing

    International Nuclear Information System (INIS)

    Ritcey, G.M.; Haque, K.E.; Lucas, B.H.; Skeaff, J.M.

    1983-01-01

    The authors have developed a complete method of recovering separately uranium, thorium and radium from impure solids such as ores, concentrates, calcines or tailings containing these metals. The technique involves leaching, in at least one stage. The impure solids in finely divided form with an aqueous leachant containing HCl and/or Cl 2 until acceptable amounts of uranium, thorium and radium are dissolved. Uranium is recovered from the solution by solvent extraction and precipitation. Thorium may also be recovered in the same manner. Radium may be recovered by at least one ion exchange, absorption and precipitation. This amount of iron in the solution must be controlled before the acid solution may be recycled for the leaching process. The calcine leached in the first step is prepared in a two stage roast in the presence of both Cl 2 and a metal sulfide. The first stage is at 350-450 0 and the second at 550-700 0

  15. Feasibility study of the dissolution rates of uranium ore dust, uranium concentrates and uranium compounds in simulated lung fluid

    International Nuclear Information System (INIS)

    Robertson, R.

    1986-01-01

    A flow-through apparatus has been devised to study the dissolution in simulated lung fluid of aerosol materials associated with the Canadian uranium industry. The apparatus has been experimentally applied over 16 day extraction periods to approximately 2g samples of < 38um and 53-75um particle-size fractions of both Elliot Lake and Mid-Western uranium ores. The extraction of uranium-238 was in the range 24-60% for these samples. The corresponding range for radium-226 was 8-26%. Thorium-230, lead-210, polonium-210, and thorium-232 were not significantly extracted. It was incidentally found that the elemental composition of the ores studied varies significantly with particle size, the radionuclide-containing minerals and several extractable stable elements being concentrated in the smaller size fraction. Samples of the refined compounds uranium dioxide and uranium trioxide were submitted to similar 16 day extraction experiments. Approximately 0.5% of the uranium was extracted from a 0.258g sample of unsintered (fluid bed) uranium dioxide of particle size < 38um. The corresponding figure for a 0.292g sample of uranium trioxide was 97%. Two aerosol samples on filters were also studied. Of the 88ug uranium initially measured on stage 2 of a cascade impactor sample collected from the yellow cake packing area of an Elliot Lake mill, essentially 100% was extracted over a 16 day period. The corresponding figure for an open face filter sample collected in a fuel fabrication plant and initially measured at 288ug uranium was approximately 3%. Recommendations are made with regard to further work of a research nature which would be useful in this area. Recommendations are also made on sampling methods, analytical methods and extraction conditions for various aerosols of interest which are to be studied in a work of broader scope designed to yield meaningful data in connection with lung dosimetry calculations

  16. Uranium mining

    International Nuclear Information System (INIS)

    Lange, G.

    1975-01-01

    The winning of uranium ore is the first stage of the fuel cycle. The whole complex of questions to be considered when evaluating the profitability of an ore mine is shortly outlined, and the possible mining techniques are described. Some data on uranium mining in the western world are also given. (RB) [de

  17. Uranium enrichment

    International Nuclear Information System (INIS)

    1989-01-01

    GAO was asked to address several questions concerning a number of proposed uranium enrichment bills introduced during the 100th Congress. The bill would have restructured the Department of Energy's uranium enrichment program as a government corporation to allow it to compete more effectively in the domestic and international markets. Some of GAO's findings discussed are: uranium market experts believe and existing market models show that the proposed DOE purchase of a $750 million of uranium from domestic producers may not significantly increase production because of large producer-held inventories; excess uranium enrichment production capacity exists throughout the world; therefore, foreign producers are expected to compete heavily in the United States throughout the 1990s as utilities' contracts with DOE expire; and according to a 1988 agreement between DOE's Offices of Nuclear Energy and Defense Programs, enrichment decommissioning costs, estimated to total $3.6 billion for planning purposes, will be shared by the commercial enrichment program and the government

  18. Uranium resources

    International Nuclear Information System (INIS)

    1976-01-01

    This is a press release issued by the OECD on 9th March 1976. It is stated that the steep increases in demand for uranium foreseen in and beyond the 1980's, with doubling times of the order of six to seven years, will inevitably create formidable problems for the industry. Further substantial efforts will be needed in prospecting for new uranium reserves. Information is given in tabular or graphical form on the following: reasonably assured resources, country by country; uranium production capacities, country by country; world nuclear power growth; world annual uranium requirements; world annual separative requirements; world annual light water reactor fuel reprocessing requirements; distribution of reactor types (LWR, SGHWR, AGR, HWR, HJR, GG, FBR); and world fuel cycle capital requirements. The information is based on the latest report on Uranium Resources Production and Demand, jointly issued by the OECD's Nuclear Energy Agency (NEA) and the International Atomic Energy Agency. (U.K.)

  19. Transfer of Plutonium-Uranium Extraction Plant and N Reactor irradiated fuel for storage at the 105-KE and 105-KW fuel storage basins, Hanford Site, Richland Washington

    International Nuclear Information System (INIS)

    1995-07-01

    The U.S. Department of Energy (DOE) needs to remove irradiated fuel from the Plutonium-Uranium Extraction (PUREX) Plant and N Reactor at the Hanford Site, Richland, Washington, to stabilize the facilities in preparation for decontamination and decommissioning (D ampersand D) and to reduce the cost of maintaining the facilities prior to D ampersand D. DOE is proposing to transfer approximately 3.9 metric tons (4.3 short tons) of unprocessed irradiated fuel, by rail, from the PUREX Plant in the 200 East Area and the 105 N Reactor (N Reactor) fuel storage basin in the 100 N Area, to the 105-KE and 105-KW fuel storage basins (K Basins) in the 100 K Area. The fuel would be placed in storage at the K Basins, along with fuel presently stored, and would be dispositioned in the same manner as the other existing irradiated fuel inventory stored in the K Basins. The fuel transfer to the K Basins would consolidate storage of fuels irradiated at N Reactor and the Single Pass Reactors. Approximately 2.9 metric tons (3.2 short tons) of single-pass production reactor, aluminum clad (AC) irradiated fuel in four fuel baskets have been placed into four overpack buckets and stored in the PUREX Plant canyon storage basin to await shipment. In addition, about 0.5 metric tons (0.6 short tons) of zircaloy clad (ZC) and a few AC irradiated fuel elements have been recovered from the PUREX dissolver cell floors, placed in wet fuel canisters, and stored on the canyon deck. A small quantity of ZC fuel, in the form of fuel fragments and chips, is suspected to be in the sludge at the bottom of N Reactor's fuel storage basin. As part of the required stabilization activities at N Reactor, this sludge would be removed from the basin and any identifiable pieces of fuel elements would be recovered, placed in open canisters, and stored in lead lined casks in the storage basin to await shipment. A maximum of 0.5 metric tons (0.6 short tons) of fuel pieces is expected to be recovered

  20. Uranium supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Spriggs, M J

    1976-01-01

    Papers were presented on the pattern of uranium production in South Africa; Australian uranium--will it ever become available; North American uranium resources, policies, prospects, and pricing; economic and political environment of the uranium mining industry; alternative sources of uranium supply; whither North American demand for uranium; and uranium demand and security of supply--a consumer's point of view. (LK)

  1. Selective leaching of uranium from uranium-contaminated soils: Progress report 1

    International Nuclear Information System (INIS)

    Francis, C.W.; Mattus, A.J.; Farr, L.L.; Elless, M.P.; Lee, S.Y.

    1993-02-01

    Three soils and a sediment contaminated with uranium were used to determine the effectiveness of sodium carbonate and citric acid leaching to decontaminated or remove uranium to acceptable regulatory levels. Two of the soils were surface soils from the DOE facility formerly called the Feed Materials Production Center (FMPC) at Fernald, Ohio. This facility is presently called the Femald Environmental Management Project (FEMP). Carbonate extractions generally removed from 70 to 90% of the uranium from the Fernald storage pad soil. Uranium was slightly more difficult to extract from the Fernald incinerator and the Y-12 landfarm soils. Very small amounts of uranium could be extracted from the storm sewer sediment. Extraction with carbonate at high solution-to-soil ratios were as effective as extractions at low solution-to-soil ratios, indicating attrition by the paddle mixer was not significantly different than that provided in a rotary extractor. Also, pretreatments such as milling or pulverizing the soil sample did not appear to increase extraction efficiency when carbonate extractions were carried out at elevated temperatures (60 degree C) or long extraction times (23 h). Adding KMnO 4 in the carbonate extraction appeared to increase extraction efficiency from the Fernald incinerator soil but not the Fernald storage pad soil. The most effective leaching rates (> 90 % from both Fernald soils) were obtained using a citrate/dithionite extraction procedure designed to remove amorphous (noncrystalline) iron/aluminum sesquioxides from surfaces of clay minerals. Citric acid also proved to be a very good extractant for uranium

  2. Application of bacterial leaching technology to deep solution-mining conditions for uranium extraction. Final report, September 1, 1978-September 30, 1981

    International Nuclear Information System (INIS)

    Brierley, J.A.; Brierley, C.L.; Torma, A.E.

    1982-03-01

    Microorganisms were evaluated for use in recovery of uranium under conditions of in-situ solution mining. The cultures tested were Thiobacillus ferrooxidans, the faculative-thermophilic TH3 strain, and two Sulfolobus species. Growth of the organisms occurred in the presence of 0.34 to 5.0 mM uranyl ion with higher concentrations being inhibitory. Uranium ore from the Anaconda Minerals Co. Jackpile mine was not readily leachable by microorganisms. To support bacterial activity the ore was supplemented with pyrite or ferrous iron. The ore possessed some toxic properties. T. ferrooxidans was able to assist in leaching of uranium from the ore at a hydrostatic pressure of 10.3 MPa

  3. Extração líquido-líquido de urânio(VI do colofanito de itataia (Santa Quitéria, Ceará por extratantes orgânicos em presença de ácido fosfórico Liquid-liquid extraction of uranium(VI from colofanite of itataia (Santa Quitéria, Ceará by organic extractants in the presence of phosphoric acid

    Directory of Open Access Journals (Sweden)

    Valeria Aparecida Leitão Ribeiro

    2008-01-01

    Full Text Available This work describes the liquid-liquid extraction of uranium after digestion of colofanite (a fluoroapatite from Itataia with sulfuric acid. The experiments were run at room temperature in one stage. Among the solutions tested the highest distribution coefficient (D > 60 was found for 40%vol. DEHPA (di(2-ethyl-hexylphosphoric acid + 20% vol. TOPO (trioctylphosphine oxide in kerosene. Thorium in the raffinate was quantitatively extracted by TOPO (0.1% vol. in cyclohexane. Uranium stripping and separation from iron was possible using 1.5 mol L-1 ammonium or sodium carbonate (room temperature, one stage. However, pH control is essential for a good separation.

  4. URANIUM DECONTAMINATION WITH RESPECT TO ZIRCONIUM

    Science.gov (United States)

    Vogler, S.; Beederman, M.

    1961-05-01

    A process is given for separating uranium values from a nitric acid aqueous solution containing uranyl values, zirconium values and tetravalent plutonium values. The process comprises contacting said solution with a substantially water-immiscible liquid organic solvent containing alkyl phosphate, separating an organic extract phase containing the uranium, zirconium, and tetravalent plutonium values from an aqueous raffinate, contacting said organic extract phase with an aqueous solution 2M to 7M in nitric acid and also containing an oxalate ion-containing substance, and separating a uranium- containing organic raffinate from aqueous zirconium- and plutonium-containing extract phase.

  5. Uranium, depleted uranium, biological effects; Uranium, uranium appauvri, effets biologiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

  6. Uranium toxicology

    International Nuclear Information System (INIS)

    Ferreyra, Mariana D.; Suarez Mendez, Sebastian

    1997-01-01

    In this paper are presented the methods and procedures optimized by the Nuclear Regulatory Authority (ARN) for the determination of: natural uranium mass, activity of enriched uranium in samples of: urine, mucus, filters, filter heads, rinsing waters and Pu in urine, adopted and in some cases adapted, by the Environmental Monitoring and Internal Dosimetry Laboratory. The analyzed material corresponded to biological and environmental samples belonging to the staff professionally exposed that work in plants of the nuclear fuel cycle. For a better comprehension of the activities of this laboratory, it is included a brief description of the uranium radiochemical toxicity and the limits internationally fixed to preserve the workers health

  7. Inherently safe in situ uranium recovery

    International Nuclear Information System (INIS)

    Krumhansl, James Lee; Beauheim, Richard Louis; Brady, Patrick Vane; Arnold, Bill Walter; Kanney, Joseph F.; McKenna, Sean Andrew

    2009-01-01

    Expansion of uranium mining in the United States is a concern to some environmental groups and sovereign Native American Nations. An approach which may alleviate some problems is to develop inherently safe in situ uranium recovery ('ISR') technologies. Current ISR technology relies on chemical extraction of trace levels of uranium from aquifers that, once mined, can still contain dissolved uranium and other trace metals that are a health concern. Existing ISR operations are few in number; however, high uranium prices are driving the industry to consider expanding operations nation-wide. Environmental concerns and enforcement of the new 30 ppb uranium drinking water standard may make opening new mining operations more difficult and costly. Here we propose a technological fix: the development of inherently safe in situ recovery (ISISR) methods. The four central features of an ISISR approach are: (1) New 'green' leachants that break down predictably in the subsurface, leaving uranium, and associated trace metals, in an immobile form; (2) Post-leachant uranium/metals-immobilizing washes that provide a backup decontamination process; (3) An optimized well-field design that increases uranium recovery efficiency and minimizes excursions of contaminated water; and (4) A combined hydrologic/geochemical protocol for designing low-cost post-extraction long-term monitoring. ISISR would bring larger amounts of uranium to the surface, leave fewer toxic metals in the aquifer, and cost less to monitor safely - thus providing a 'win-win-win' solution to all stakeholders.

  8. Rossing uranium

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    In this article the geology of the deposits of the Rossing uranium mine in Namibia is discussed. The planning of the open-pit mining, the blasting, drilling, handling and the equipment used for these processes are described

  9. Uranium separation from phosphates and the fuel cycle process

    International Nuclear Information System (INIS)

    Lavi, J.

    1978-01-01

    A short introduction on the recycle of uranium and plutonium is presented. The uranium world market at present, the prices during the last few years, the actual requirements and those for the years 1978-1983 are given. In a special paragraph the present resources of uranium in Israel as well as the extraction possibilities are discussed. (B.G.)

  10. Automated fluorometer for uranium analysis

    International Nuclear Information System (INIS)

    McElhaney, R.J.; Caylor, J.D.; Cole, S.H.; Futrell, T.L.; Giles, V.M.

    1978-03-01

    An utomated fluorometer has proven to be a valuable analytical tool for analyzing natural waters for the Uranium Resource Evaluation (URE) project. Uranium is isolated from potential quenching ions and concentrated by extraction with tri-n-octylphosphine oxide (TOPO) in Varsol. A portion of the extract is placed on a sodium fluoride pellet which is then dried, sintered, and cooled. Sixteen samples can be analyzed in about 1.5 hours. The lower reporting limit has been set at 0.20 micrograms per liter

  11. Uranium, depleted uranium, biological effects

    International Nuclear Information System (INIS)

    2001-01-01

    Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

  12. Process for recovery of uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Wiewiorowski, T.K.; Thornsberry, W.L. Jr.

    1978-01-01

    Process is claimed for the recovery of uranium from wet process phosphoric acid solution in which an organic extractant, containing uranium values and dissolved iron impurities and comprising a dialkylphosphoric acid and a trialkylphosphine oxide dissolved in a water immiscible organic solvent, is contacted with a substantially iron-free dilute aqueous phosphoric acid to remove said iron impurities. The removed impurities are bled from the system by feeding the resulting iron-loaded phosphoric acid to a secondary countercurrent uranium extraction operation from which they leave as part of the uranium-depleted acid raffinate. Also, process for recovering uranium in which the extractant, after it has been stripped of uranium values by aqueous ammonium carbonate, is contacted with a dilute aqueous acid selected from the group consisting of H 2 SO 4 , HCl, HNO 3 and iron-free H 3 PO 4 to improve the extraction efficiency of the organic extractant

  13. Uranium loans

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    When NUEXCO was organized in 1968, its founders conceived of a business based on uranium loans. The concept was relatively straightforward; those who found themselves with excess supplies of uranium would deposit those excesses in NUEXCO's open-quotes bank,close quotes and those who found themselves temporarily short of uranium could borrow from the bank. The borrower would pay interest based on the quantity of uranium borrowed and the duration of the loan, and the bank would collect the interest, deduct its service fee for arranging the loan, and pay the balance to those whose deposits were borrowed. In fact, the original plan was to call the firm Nuclear Bank Corporation, until it was discovered that using the word open-quotes Bankclose quotes in the name would subject the firm to various US banking regulations. Thus, Nuclear Bank Corporation became Nuclear Exchange Corporation, which was later shortened to NUEXCO. Neither the nuclear fuel market nor NUEXCO's business developed quite as its founders had anticipated. From almost the very beginning, the brokerage of uranium purchases and sales became a more significant activity for NUEXCO than arranging uranium loans. Nevertheless, loan transactions have played an important role in the international nuclear fuel market, requiring the development of special knowledge and commercial techniques

  14. Uranium mining operations in Spain

    International Nuclear Information System (INIS)

    Rios, J.-M.; Arnaiz, J.; Criado, M.; Lopez, A.

    1995-01-01

    The Empresa Nacional del Uranio, SA (ENUSA) was founded in 1972 to undertake and develop the industrial and procurement activities of the nuclear fuel cycle in Spain. Within the organisation of ENUSA, the Uranium Division is directly responsible for the uranium mining and production operations that have been carried out since 1973 in the area of Ciudad Rodrigo in the province of Salamanca. These activities are based on open pit mining, heap leaching and a hydrometallurgical plant (Elefante) for extracting uranium concentrates from the ore. This plant was shut down in 1993 and a new plant was started up on the same site (Quercus) with a dynamic leaching process. The nominal capacity of the new plant is 950 t U 3 O 8 per year. Because of the historically low uranium prices which have recently prevailed, the plant is currently running at a strategic production rate of 300 t U 3 O 8 per year. From 1981 to 1990, in the area of La Haba (Badajoz province), ENUSA also operated a uranium production site, based on open pit mining, and an experimental extraction plant (Lobo-G). ENUSA is currently decommissioning these installations. This paper describes innovations and improvements that ENUSA has recently introduced in the field of uranium concentrates production with a view to cutting production costs, and to improving the decommissioning and site restoration processes in those sites where production is being shut down or resources have been worked out. (author)

  15. Uranium recovery from phosphonitric solutions

    International Nuclear Information System (INIS)

    Bunus, F.T.; Miu, I.

    1997-01-01

    A new technology for uranium and rare earth recovery applied in a semi-industrial plant processing 5 m 3 /h phosphoric acid has been extended to phosphonitric solution, resulting in the process of nitric acid attack of phosphate rock for complex fertilizer production. In this process uranium and rare earths are obtained at larger quantities due to the complete dissolution of elements involved. The method is based on a one cycle extraction-stripping process using as extractants: di(2-ethylhexyl) phosphate (DEPA) in mixture either with tri-n-butylphosphate (TBP) or tri-n-octylphosphine oxide (TOPO) in view of obtaining a synergic effect for U (VI). A mixer-settler extractor in four steps was used. Two stripping steps are involved for the elements mentioned. Before uranium stripping a scrubbing with urea was introduced to eliminate nitric acid extracted. Uranium was obtained as green cake (hydrated uranium tetrafluoride) which can be easily transformed in hexfluoride or converted to a diuranate. At the same time the radium is also eliminated leading to a non-radioactive fertilizer product. (author),. 8 refs, 4 figs

  16. The second last grain of uranium

    International Nuclear Information System (INIS)

    Pendreigh, R.

    1978-01-01

    High pressure leaching can increase uranium extraction from some low grade ores by ten per cent, and Anglo American Corporation's eighteen months of pilot plant tests point the way to commercial application

  17. More light on the U clan. [Uranium behaviour in complex ores

    Energy Technology Data Exchange (ETDEWEB)

    De Waal, S.A. (Potchefstroom Univ. for C.H.E. (South Africa). Dept. of Geology)

    1983-07-01

    A thorough knowledge of the geochemistry of uranium is necessary for the exploration and beneficiation of this mineral. At present we lack knowledge of the behaviour of uranium minerals in complex ores. This article deals with the geochemistry of uranium, its group identity, uranium minerals and the extraction mineralogy.

  18. Environmental restoration plans and activities in the zones of uranium ore extraction and milling in Romania: 1995-1996 progress report

    International Nuclear Information System (INIS)

    Bejenaru, C.; Ionescu, I.; Georgescu, D.

    1997-01-01

    The objective of this paper is to present the ecological impact on environment as a consequence of more than 30 years of activity in the field of uranium exploration, mining and ore processing in Romania and a brief description of the measures taken for limiting the effects of contamination on the affected zones including the proposed restructuring and rehabilitation programmes. The Autonomous Regie for Rare Metals (RAMR), the coordinator of the activities in the uranium field is responsible to implement the provisions of the IAEA Technical Cooperation Project on Environmental Restoration in Central and Eastern Europe joined by Romania in 1993. The characterization of radioactively contaminated areas is dealt with broadly under two categories, one pertaining to sites where the mining and milling activities have already ceased and the other where the units are still operational but are going to be closed down in the near future and will be placed under surveillance. Generally speaking, the activity in the uranium field is developed by observing the national Norms of Nuclear Safety for the Activity of Geological Investigation, Mining and Milling of Nuclear Raw Material. This report includes an evaluation of the necessary investments for the first stage of the programme dealing with the environmental restoration and the necessary research activities. This will be followed by studies for closing down and surveillance of the mines with special problems taking into account their depth and complex hydrology

  19. Uranium enrichment

    International Nuclear Information System (INIS)

    Rae, H.K.; Melvin, J.G.

    1988-06-01

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  20. International uranium production. Namibian perspective

    International Nuclear Information System (INIS)

    Daniel, P.

    1984-01-01

    The Rossing uranium deposit is the only one currently being mined in Namibia. Construction began in 1974 and production started in 1979. Current production is close to 4800 s.t. U3O8 per annum. About 160 000 mt of ore and waste are removed from the open pit every day. Each truck load is radiometrically scanned to determine ore grade and is discharged either directly into the primary crusher or into low-grade stockpiles. The uranium is extracted in a sulphuric acid leaching plant and upgraded in an ion exchange and solvent extraction plant. An ion exchange plant recovers uranium from the tailings solution. Three thousand people are employed at the mine, most living in the nearby town site. Employee training and development are emphasized. Employee health is carefully monitored; no occupationally-related disease has been reported. Rossing contributes one third of the GNP of Namibia. (L.L.)