Articles de revues : « Extraction uranium »

1

Borts, B., S. Ivanova, I. Koliabina, G. Lysychenko et V. Tkachenko. « Supercritical Extraction by Carbon Dioxide of Uranium from Ore Concentrates and Low-Enriched Ores of Tailing ». Nuclear and Radiation Safety, n^o 2(70) (20 mai 2016) : 56–60. http://dx.doi.org/10.32918/nrs.2016.2(70).12.

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The extraction and processing of uranium ores in Ukraine have led to the accumulation of large amounts of waste. It is obvious that the old technologies are not applicable to the extraction of uranium from such waste. Therefore, the search for the new, more efficient methods of extracting residual amounts of waste nutrients and subsequent improvement of the environmental status of contaminated areas are both necessary. The supercritical carbon dioxide fluid extraction (SFE-CO2) is proposed as a method that can be utilized independently or as the last step of the acid leaching method adopted at VostGOK to extract the uranium. The efficiency of uranium SFE-CO2 can reach 98%.

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Yang, Xiaoying, Mei Cui, Rongxin Su et Renliang Huang. « The Preparation of a Polyamidoxime–Phosphorylated Cellulose Nanofibrils Composite Aerogel for the Selective Extraction of Uranium from Seawater ». Nanomaterials 14, n^o 15 (1 août 2024) : 1297. http://dx.doi.org/10.3390/nano14151297.

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Uranium is the most important fuel for nuclear power operations, and the safe supply of its resources is the key to the development of nuclear power in China. Because of the complex seawater environment and extremely low uranium concentration, extracting uranium from natural seawater poses a significant challenge. In this study, a polyamidoxime–phosphorylated cellulose nanofibril composite aerogel was prepared as an adsorbent for uranium extraction from seawater. An adsorption kinetics test, equilibrium adsorption isotherm model fitting, an adsorption–desorption cycle test, and a selectivity test were carried out to evaluate the adsorption performance of the composite aerogel for uranium extraction. The adsorption capacities for the initial concentrations of 4 and 8 ppm in uranium-spiked pure water were 96.9 and 204.3 mg-U/g-Ads, respectively. The equilibrium uranium adsorption capacities of uranium-spiked simulated seawater were 38.9 and 51.7 mg-U/g-Ads, respectively. The distribution coefficient KD of uranium was calculated to be 2.5 × 107 mL/g. The results show that the polyamidoxime–phosphorylated cellulose nanofiber composite aerogels prepared in this study have the advantages of low cost and high uranium selectivity for uranium extraction from seawater.

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Liu, Peng, Minyan An, Teng He, Ping Li et Fuqiu Ma. « Recent Advances in Antibiofouling Materials for Seawater-Uranium Extraction : A Review ». Materials 16, n^o 19 (28 septembre 2023) : 6451. http://dx.doi.org/10.3390/ma16196451.

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Nuclear power has experienced rapid development as a green energy source due to the increasing global demand for energy. Uranium, as the primary fuel for nuclear reactions, plays a crucial role in nuclear energy production, and seawater-uranium extraction has gained significant attention. However, the extraction of uranium is usually susceptible to contamination by microorganisms, such as bacteria, which can negatively affect the adsorption performance of uranium adsorption materials. Therefore, an important challenge lies in the development of new antibacterial and antiadhesion materials to inhibit the attachment of marine microorganisms. These advancements aim to reduce the impact on the adsorption capability of the adsorbent materials. This paper reviews the antibiofouling materials used for extracting seawater uranium, and corresponding mechanisms are discussed.

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Wang, Wei Guang, Kai Xuan Tan, Er Ju Xie, Jiang Liu et Gui Long Cai. « Supercritical CO₂ Fluid Leaching of Uranium from Sandstone Type Ores ». Advanced Materials Research 634-638 (janvier 2013) : 3517–21. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.3517.

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Uranium is an important fuel for nuclear power, so the mining and milling of uranium is the base for development of nuclear power. Our experiments study is about the supercritical CO2 fluid extraction of uranium in low grade uranium ore, and the influence of aqueous medium, oxidants, chelating agents and other factors on the uranium leaching. In aqueous media, Fe2 (SO4)3 as the oxidants, supercritical CO2 fluid extraction of uranium has the best effect, the uranium leaching rate reaches 90.44%, significantly higher than that of the conventional acid and alkaline leaching. In the process of extraction of uranium in supercritical CO2 fluid, the uranium in uranium ore is first oxidized to hexavalent uranium, and then forms high solubility of uranyl carbonate complexes. Supercritical CO2 fluid is expected to be used in in-situ leaching of uranium mining of the low grade sandstone uranium deposits.

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Bishimbayeva, G. K., A. M. Nalibayeva, S. A. Saidullayeva, A. K. Zhangabayeva, A. Bold, D. S. Zhumabayeva, Y. N. Abdikalykov et E. N. Panova. « EXTRACTION PROPERTIES OF SYNTHESIZED FLUORINATED ORGANOPHOSPHORUS COMPOUNDS ». RASAYAN Journal of Chemistry 16, n^o 01 (2023) : 440–46. http://dx.doi.org/10.31788/rjc.2023.1618246.

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This work presents the results of studies of extraction properties in relation to the uranium of bis(2,2,2- trifluoroethyl)diallylamido phosphite, bis(2,2,2-trifluoroethyl)dimethylamido phosphite, and bis(N,Ndialamido)isopropyl phosphite synthesized by us earlier. Tests were carried out in a factory laboratory, as the initial solutions used nitrate solution prepared from uranium oxide (CU = 10.30 g/dm3 , CHNO3 = 56.40 g/dm3 ) and uranium sulfate solution prepared from the chemical concentrate of natural uranium and deoxidized with sulfuric acid (CU = 10.60 g/dm3 , CH2SO4 = 25.10 g/dm3 ). It was proved that the synthesized acyclic amido phosphites can effectively extract uranium from these technological solutions with a proper selection of technological parameters, and the degree of uranium extraction may vary from 34.43 to 95.94%.

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Kafka, Tomáš. « Uranium industry and Ralsko ». Geografie 103, n^o 3 (1998) : 382–89. http://dx.doi.org/10.37040/geografie1998103030382.

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The former Ralsko military training area is situated in close proximity to the region where uranium is mined. The paper deals with the history of uranium mining and with geological conditions of the territory and characterizes the methods of extraction used - deep mining of uranium ore and chemical extraction by in-situ lixiviation. Attention is paid to the present organization structure of the uranium industry and to the work of the state firm DIAMO with regard to the elimination of impacts of uranium ore extraction and processing.

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Kafka, Tomáš. « Uranium industry and Ralsko ». Geografie 103, n^o 3 (1998) : 253–60. http://dx.doi.org/10.37040/geografie1998103030253.

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The former Ralsko military training area is situated in close proximity to the region where uranium is mined. The paper deals with the history of uranium mining and with geological conditions of the territory and characterizes the methods of extraction used - deep mining of uranium ore and chemical extraction by in-situ leaching. Attention is paid to the present organization structure of the uranium industry and to the work of the state firm DIAMO with regard to the elimination of impacts of uranium ore extraction and processing.

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Afonin, Mikhail A., Vadim V. Romanovski et Vadim A. Scherbakov. « OSCILLATORY EXTRACTION OF URANIUM ». Solvent Extraction and Ion Exchange 16, n^o 5 (août 1998) : 1215–31. http://dx.doi.org/10.1080/07360299808934577.

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Khan, Naeemullah, Mustafa Tuzen et Tasneem Gul Kazi. « 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 ». Journal of AOAC INTERNATIONAL 100, n^o 6 (1 novembre 2017) : 1848–53. http://dx.doi.org/10.5740/jaoacint.17-0054.

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Abstract 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.

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Maher, Chris J., Christine Bouyer, Tamara L. Griffiths, Solène Legand, Gilles Leturcq, Manuel Miguirditchian et Mark Sarsfield. « Impact of uranium carbide organics treated by prolonged boiling and electrochemical oxidation upon uranium and plutonium solvent extraction ». Radiochimica Acta 106, n^o 2 (26 janvier 2018) : 95–106. http://dx.doi.org/10.1515/ract-2017-2799.

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AbstractThe dissolution of uranium or uranium-plutonium carbide fuel in nitric acid leads to ~50% carbon evolved as carbon dioxide, the remainder remains in the solution as soluble organics. These dissolved organic molecules interfere with the solvent extraction of uranium and plutonium by complexing to the actinide ions and decreasing the efficiency of their extraction. Experiments reported here describe two series of experiments assessing the uranium carbide dissolution liquor treatment by prolonged boiling and electrochemical oxidation. Plutonium losses to aqueous and solvent raffinates are observed for untreated liquors, highlighting that mineralisation of dissolved organics is necessary to reduce the complexing effects of organic acids to an extent that permit efficient operation of a solvent extraction process both in the first solvent use (considered here) and for maintaining solvent quality during industrial solvent reuse in the highly active cycle. Solution carbon analysis and 30% TBP solvent extraction batch tests of uranium and plutonium originating from dissolved uranium carbide liquors untreated and after treatment are compared. These experiments demonstrate the reprocessing of uranium carbides by direct dissolution coupled to a mineralisation process, can achieve near quantitative uranium and high plutonium recoveries (99.9%).

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Rasskazov, Igor, Artur Sekisov et Anna Rasskazova. « In-situ leaching of molybdenum and uranium by percarbonate and chloride-hypochlorite solutions ». Записки Горного института 256 (10 novembre 2022) : 623–31. http://dx.doi.org/10.31897/pmi.2022.60.

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In-situ leaching of molybdenum and uranium is becoming an increasingly common process. The features of the material composition of ores, leading to a decrease in their filtration properties, were considered. Activation leaching with leaching solutions that have undergone electrophotochemical activation before contact with the ore mass were studied. Activation preparation of leaching solutions promotes the synthesis of clustered water molecules with collectivized protons and hydroxyl ions, as well as active forms of oxygen and hydrogen. Cell leaching of molybdenum from mature tailings of the Shakhtaminsk deposit was studied experimentally. After pre-oxidation with an active carbonate solution, a model borehole leaching was carried out with a chloride-hypochlorite solution. Molybdenum extraction on resin a was 85 % in 30 days. Experiments on the percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits confirmed the potential possibility of a significant increase in the extraction of uranium by electrophotoactivated percarbonate solutions relative to aqueous solutions of sodium and ammonium carbonate. When leaching with carbonate solutions without an additional oxidizing agent, the extraction of uranium from the Sugraly deposit ore sample was 52 and 59 % (sodium carbonate and ammonium carbonate). The use of hydrogen peroxide as an oxidizing agent made it possible to achieve 87-88 % extraction into pregnant solutions in 21 days without pre-oxidation. The performed studies confirm the processing capability of extracting uranium and molybdenum by percolation leaching in columns and borehole leaching.

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Pi, Yin An, Jing Song Wang, Qing Wei Guo, Hui Yan Mo, Yong Feng Xia et Xiao Liang Zou. « The Complexation of Calix[6]Arene Sulfoxide Derivative with Uranium ». Advanced Materials Research 842 (novembre 2013) : 170–74. http://dx.doi.org/10.4028/www.scientific.net/amr.842.170.

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Calix[6]arene carbon chain alkyl sulfoxide derivative have been successfully synthesized. IR spectra confirmed the introduction of sulfoxide group on calix[6]arene. UV spectra indicated that calix[6]arene sulfoxide derivative has a high complexation of uranium. The coordination ratio between the calix[6]arene sulfoxide derivative with uranium is 3:2, which was determined by Job’s method. Extraction experiments showed that the extraction efficiency of uranium is able to achieve 73.8%, which suggested the potential application of calix[6]arene sulfoxide derivative as an excellent uranium extraction agent.

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Ghaemi, Ahad, Mehdi Maghsudi, Fatemeh Hanifpour et Mohammad Samadfam. « Preparation of a Uranium Conversion Plant’s Nuclear Waste for Final Disposal by Means of Magnetically Assisted Chemical Separation ». International Journal of Chemoinformatics and Chemical Engineering 3, n^o 1 (janvier 2013) : 8–18. http://dx.doi.org/10.4018/ijcce.2013010102.

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Uranium is separated from the raffinate of Isfahan’s uranium conversion solvent extraction process by means of solvent coated magnetic nanoparticles. These particles were synthesized via chemical co-precipitation and were analyzed by XRD, TEM and TGA methods. The particles’ surface were modified with D2EHPA and analyzed with FT-IR method. The results revealed that 0.5 M nitric acid and 25% w/w D2EHPA on nanoparticles gives the maximum uranium extraction yield. The raffinate of the solvent extraction plant can be disposed safely after its uranium content reduces to the allowable values.

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Sanakulov, Kuvandik, Ulugbek Sharafutdinov, Ibodulla Razhabboev, Rustam Khamidov et Madina Khamidova. « Study of technological parameters of ion exchange resins and technology of recultivation of off-balance uranium-containing dumps ». E3S Web of Conferences 548 (2024) : 08015. http://dx.doi.org/10.1051/e3sconf/202454808015.

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The article presents the technology of uranium extraction, the results of uranium extraction from recultivative dumps, physicochemical and technological properties of applied resins, as well as the state of radiation and ecological situation in the area of uranium ore mining enterprise location around the town of Uchkuduk (Uzbekistan). Nowadays, worldwide scientific research is being conducted on the return of technogenic waste to the main processing, application of high-quality sorbents based on chloride ions in the process of obtaining the finished product, uranium recovery in the process of sorption, improvement of the main indicators of uranium production and processing of technogenic dumps by means of their return. In this regard, it is necessary to develop physicchemical and technological fundamentals of technogenic waste processing, recultivation of sites, study the properties of anionites sorbing uranium in the process of uranium waste processing with highly concentrated solutions of chloride ions, pay special attention to scientific research on uranium extraction under conditions of seasonal low temperatures in the process of sorption.

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Khanramaki, Fereshte, Jaber Safdari, Amir S. Shirani et Rezvan Torkaman. « Investigations on the complete removal of iron(III) interference on the uranium(VI) extraction from sulfate leach liquor using Alamine 336 in kerosene ». Radiochimica Acta 106, n^o 8 (28 août 2018) : 631–43. http://dx.doi.org/10.1515/ract-2017-2906.

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Abstract Uranyl sulfate obtained by uranium ore leaching of an industrial sample deposit of Gachin site was used for uranium separation by the solvent extraction technique. The presence of other elements in the sulfate leach liquors has a negative impact on the uranium extraction process using Alamine 336; therefore, the operating costs are increased. In this study, the separation of uranium(VI) and iron(III) by Alamine 336 and kerosene have been examined as an extractant and a diluent, respectively. For this purpose, the effects of operating parameters on the extraction process such as Alamine 336 concentration, modifier concentration, contact time, initial aqueous pH, sulfate ion concentration, temperature, and stripping agents were investigated. Also, the complete removal of iron(III) interference from the sulfate leach liquor before the extraction step has been studied with reducing agents. The equilibrium constants and stoichiometric coefficients for uranium and iron extraction with Alamine 336 in the sulfate leach liquors were calculated. Likewise, the values of the thermodynamic parameters such as Gibbs energy, enthalpy and entropy were determined to prove the exothermic and spontaneous reactions. The mentioned procedure is proposed for the uranium separation from the impurities in the sulfate ores using tertiary amine for production of purified uranium.

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Gao, Wei, Yantong Long, Yefan Qing et Chen Xu. « A novel strategy for efficient uranium extraction and energy storage : Uranium extraction cell ». Separation and Purification Technology 339 (juillet 2024) : 126723. http://dx.doi.org/10.1016/j.seppur.2024.126723.

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Fidan Bahmanova, Sevindj Hajiyeva, Fidan Bahmanova, Sevindj Hajiyeva, et Famil Chiragov Famil Chiragov. « CONCENTRATION OF URANIUM(VI) WITH A CHELATE-FORMING SORBENT ». PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 148, n^o 02-02 (7 décembre 2024) : 238–46. https://doi.org/10.36962/pahtei14802-022024-238.

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The sorption properties of a modified sorbent based on a maleic anhydride-styrene copolymer with respect to uranium(VI) have been studied. The main quantitative characteristics of metal ion sorption are determined. A sorbent containing fragments of molon acid hydrazide for the se-lective extraction of uranium(VI) from solutions is proposed. The optimal sorption conditions were determined. The degree of extraction of uranium(VI) under optimal conditions exceeds 95%. A technique for the sorption-photometric determination of uranium(VI) in sea water has been developed. Keywords: uranium (VI), concentration, sopolymer, sorbent, sorption, determination.

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Yu, Fengtao, Fangru Song, Runze Wang, Mei Xu et Feng Luo. « Sulfonated perylene-based conjugated microporous polymer as a high-performance adsorbent for photo-enhanced uranium extraction from seawater ». Polymer Chemistry 12, n^o 6 (2021) : 867–75. http://dx.doi.org/10.1039/d0py01656j.

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A sulfonated perylene-based adsorbent is prepared for photo-enhanced uranium extraction from seawater. Owing to the photo-enhanced effect, the uranium extraction capacity of PyB-SO₃H in seawater reaches 1989 mg g⁻¹, with 90% extraction efficiency.

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Togaev, Isomiddin, Doston Buriboyev, Shoxrux Toshtemirov et Baxtinur Abdujabborov. « Mineralogical composition of the Santonian deposits of the North Konimekh deposit in Uzbekistan ». BIO Web of Conferences 65 (2023) : 09005. http://dx.doi.org/10.1051/bioconf/20236509005.

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The article presents information about the results of studying the material composition, mineralogy and geochemistry of deposits formed in the Upper Cretaceous (K2) Santon strata of the North Konimekh uranium deposit located in the Kyzylkum region. Prospecting, appraisal and exploration at the North Konimekh uranium mine is an urgent problem, as it is in the focus of attention of many researchers. This article provides extensive information on underground alkalization, one of the methods for extracting uranium raw materials. Currently, it is emphasized that this method is convenient, has high financial efficiency in the extraction of uranium raw materials, and is also one of the cheapest and most effective methods.

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Abdoul-Rachid, Chaibou Yacouba, Laouali Ibahim Salmana, Zanguina Adamou, Natatou Ibrahim et Mamane Ibrahim. « Comparative Study of Solvent Extraction of Uranium with Alamine 336 and Aliquat 336 : Application to the Uranium-Bearing Solutions of Niger Republic ». European Scientific Journal, ESJ 14, n^o 9 (31 mars 2018) : 76. http://dx.doi.org/10.19044/esj.2018.v14n9p76.

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This study focuses on the liquid-liquid extraction of uranium by anionic extractants of Alamine 336 and Aliquat 336. The objective of this study is to determine the parameters allowing the optimization of the extraction percentage of uranium, and other metals such as molybdenum, zirconium and vanadium. The extraction kinetics of uranium is achieved in 2 minutes. Sulfuric acid solutions are the media per excellence when using Alamine 336 as extractant. However,with Aliquat 336, it is orthophosphoric acid. Uranium is extracted at 99% in a single contact from the ratio: organic phase over aqueous phase (O/A) equals 1. The extraction of uranium with Alamine 336 depends on the initial pH of the aqueous phase as well as the Alamine 336 concentration. Alamine 336 tends to release the uranium and the extracted zirconium until the 3 rd contact to the benefit of the molybdenum due to the natural occurrence of 𝐶𝑙−,𝑁𝑂3 − and 𝐹 − ions in the uranium-bearing solutions which have the tendency of breaking the anion complexes. Vanadium, which is not extracted by Alamine 336 and Aliquat 336, can, in the hydrodynamic conditions of this work, be extracted by increasing the redox potential to 800 mV and pH ≥ 1.

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Borts, B., I. Koliabina, G. Lysychenko, S. Skoromnaya et V. Tkachenko. « Cost of Uranium Complexes Obtaining by Supercritical Carbon Dioxed ». Nuclear and Radiation Safety, n^o 3(75) (22 août 2017) : 60–66. http://dx.doi.org/10.32918/nrs.2017.3(75).11.

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A review of the uranium content in ores from different deposits of the world and contains the estimated cost of its production in Ukraine is presented. The quantitative characteristics of the uranium content in the tailings materials of the former uraniumprocessing plant - Production Association Pridneprovskiy Chemical Plant (PA "PCP") Dneprodzerzhinsk (since 2016 Kamensk city) is discussed. The method of supercritical fluid extraction of carbon dioxide (SFE-CO2) complexes of uranium-containing compounds for the extraction of uranium from tailings is proposed to use. The list of materials and reagents for SFE - CO2 from complexes of uranium-containing compounds is defined. The describing of procedures and their sequence for the sample preparation are done. The calculation of the cost of uranium extraction by SFE-CO2 from tailings PCP Dneprodzerzhinsk is presented. It is found that the production cost of uranium complexes may amount of 344.32 UAH/kg (13,77 USD/kg) to 457.08 UAH/kg (18,28 USD/kg) (at the rate of the NBU as of 28.01.2016 25,0054 UAH/USD).

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Wu, Maoling, Ling Ding, Jun Liao, Yong Zhang et Wenkun Zhu. « Preparation of novel porous Al₂O₃–SiO₂ nanocomposites via solution-freeze-drying-calcination method for the efficient removal of uranium in solution ». Nanotechnology 33, n^o 9 (9 décembre 2021) : 095705. http://dx.doi.org/10.1088/1361-6528/ac3c7a.

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Abstract In this work, the efficient extraction of uranium in solution using Al2O3–SiO2-T was reported. Kinetics and isotherm models indicated that the removal process of uranium on Al2O3–SiO2-T accorded with pseudo-second-order kinetic model and Langmuir isotherm model, which showed that the adsorption process was a uniform mono-layer chemical behavior. The maximum adsorption capacity of Al2O3–SiO2-T reached 738.7 mg g−1, which was higher than AlNaO6Si2 (349.8 mg g−1) and Al2O3–SiO2-NT (453.1 mg g−1), indicating that the addition of template could effectively improve the adsorption performance of Al2O3–SiO2 to uranium. Even after five cycles of adsorption–desorption, the removal percentage of uranium on Al2O3–SiO2-T remained 96%. Besides, the extraction efficiency of uranium on Al2O3–SiO2-T was 72.5% in simulated seawater, which suggested that the Al2O3–SiO2-T was expected to be used for uranium extraction from seawater. Further, the interaction mechanism between Al2O3–SiO2-T and uranium species was studied. The results showed that the electrostatic interaction and complexation played key roles in the adsorption process of Al2O3–SiO2-T to uranium.

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Kanayev, Ashimkhan T., Khussain Valiyev et Aleksandr Bulaev. « The Effect of Different Oxidants on Extraction of Uranium from Low Grade Ore ». Solid State Phenomena 299 (janvier 2020) : 1104–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.1104.

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The effect of different oxidants on extraction of uranium from low grade ore was studied. Leaching was performed using sulfuric acid solutions at a concentration of 10 to 30%. Ferric sulfate Fe2(SO4)3, ammonium persulphate (NH4)2S2O8, and potassium permanganate KMnO4 at different concentrations were used as oxidants in different variants of the experiment. In addition, solutions collected at Vostok deposit containing 6.86 g/L Fe3+ and 106 cells/mL of the bacteria Acidithiobacillusferrooxidans were used for leaching. The rate of uranium extraction with sulfuric acid solutions without oxidants was low and did not exceed 19.4%. Addition of oxidants made it possible to increase rate of uranium extraction. In the presence of ferric sulfate, ammonium persulphate, and potassium permanganate rates of uranium extraction were up to 68, 95.2, and 69.6%, respectively. The rate of uranium leaching in the experiments with the AMD sample was high and reached about 95%. Therefore, it can be concluded that using not only oxidizing agents, but AMD, which are formed during the natural oxidation of sulfide minerals contained in the ore of the deposit, can significantly increase the rate of uranium recovery.

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Parker, B. F., Z. Zhang, L. Rao et J. Arnold. « An overview and recent progress in the chemistry of uranium extraction from seawater ». Dalton Transactions 47, n^o 3 (2018) : 639–44. http://dx.doi.org/10.1039/c7dt04058j.

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There has been historical interest in harvesting uranium from seawater for nuclear energy over the past few decades, with the goal of lower extraction cost to become competitive with land-based uranium. This review provides a brief background on the extraction of uranium from seawater and on recent work from groups supported by the United States Department of Energy on this project.

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Kumar, Pradeep. « Supercritical Fluid Extraction of Uranium, Plutonium and Thorium ». Journal of ISAS 1, n^o 1 (31 juillet 2022) : 65–96. http://dx.doi.org/10.59143/isas.jisas.1.1.kmmu6765.

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In recent decades, extraction of actinides (U,Pu,Th) employing supercritical CO2has drawn attention owing to its inherent potential to minimize liquid waste generation. Supercritical Fluid Extraction (SFE) offers faster extraction with fine control over extraction process by means of varying pressure , temperature conditions. Supercritical Fluids have hybridproperties of liquid and gas. Liquid like solvation and gas like diffusivity enable topenetrate deep inside solid matrix, extracting component of interest, thus capable of extraction from liquid as well as solid matrix. Metal ion is complexed withsuitable organic compound, which gets soluble in SC CO2 . SC CO2 acts as a solvent and after extractionescapes as gas leaving behind extractant. Various types of ligands such organophosphorus compounds, -diketones, macrocyclic compounds, amides, dithiocarbamates are employed.SFE offers attractive alternative to reprocessing of spent nuclear fuel and radioactive waste.In this paper, research work carried out on the SFE of actinides (U,Pu,Th) has been reviewed.

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Turganaliev, C., E. Oryngozha, E. Oringozhin, V. Nikulin et Zh Alisheva. « Physico-chemical aspects of uranium extraction for investigation of underground well leaching control systems ». Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 329, n^o 2 (3 octobre 2023) : 5–16. http://dx.doi.org/10.31643/2024/6445.12.

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This article gives the physical and chemical aspects of uranium extraction from the zones of reservoir oxidation using ultrasonic technology and the theoretical justification for the technology of in-situ borehole leaching (ISL) of uranium deposits in Kazakhstan. Kazakhstan has significant reserves, well-explored uranium deposits, developed uranium mining and processing capacities, as well as the current state of the world uranium market, which determine the prospects for the development of the uranium mining industry in Kazakhstan. Ore deposits of uranium deposits localized at the fronts of seam oxidation zones are largely similar in terms of the chemical composition of host rocks. Fe, Al, Mg, Ca, K, and Na are among the most widespread petrogenic elements of rock-forming minerals. Uranium is observed in association with iron, vanadium, selenium, molybdenum, rhenium, and other elements. Uranium mineralization is represented by exogenous (secondary) minerals – pitchblende and coffinite. In the general balance of uranium minerals, pitchblende is about 30%, and coffinite is about 70%. Nasturan (хUO2×yUO3×z) is represented by an association of tetravalent uranium dioxide and hexavalent uranium trioxide with a variable composition (UO2+UO3) - 65-85%, coffinite - tetravalent uranium silicate USiO4.

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KATO, Shunsaku, et Takahiro HIROTSU. « Extraction of uranium from seawater. » RESOURCES PROCESSING 34, n^o 1 (1987) : 62–68. http://dx.doi.org/10.4144/rpsj1986.34.62.

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Abdikerim, B. E., B. K. Kenzhaliyev, T. Yu Surkova, N. Didik, A. N. Berkinbayeva, Z. D. Dosymbayeva et N. S. Umirbekova. « Uranium extraction with modified sorbents ». Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 3, n^o 314 (15 septembre 2020) : 84–90. http://dx.doi.org/10.31643/2020/6445.30.

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Guerinoni, Elise, Sandrine Dourdain, Thomas Dumas, Guilhem Arrachart, Fabrice Giusti, Zijun Lu, Pier-Lorenzo Solari et Stéphane Pellet-Rostaing. « Enhancing Uranium Extraction Efficiency Using Protonated Amines and Quaternary Ammoniums-Based Ionic Liquids : Mechanistic Insights and Nonlinearities Analysis ». Separations 10, n^o 9 (15 septembre 2023) : 509. http://dx.doi.org/10.3390/separations10090509.

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This study investigates uranium solvent extraction under AMEX process conditions. The use of pure extractants without diluents or phase modifiers allows us not only to reduce the use of volatile organic compounds but also to provide higher extraction yields without third-phase formation. Pure extractants are protonated amines or quaternary ammoniums with suitable counter ions, which act at the interface between ion pairs and protic ionic liquids. The mixture of sulphates anion (SO42−) and bis(trifluoromethanesulfonyl)imide anion (NTf2−) revealed unexpected nonlinear extraction behaviors, which appear highly important to rationalize for optimized application. A spectroscopic analysis (NMR, UV-vis, FT-IR, and EXAFS) showed that uranium extraction occurs via a protonated amine and three sulphates. A nonlinear extraction could further be interpreted by considering a water and acid transfer between the two phases: at lower sulphate ratios, the release of acid from the organic phase into the aqueous phase was shown to influence the number of protonated amines in the organic phase, affecting uranium extraction before its enhancement. Furthermore, the extraction loss at higher sulphate ratios was assigned to the destabilization of bidentate uranium–sulphate complexes due to a competition between water and sulphates.

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Zhu, Wangchuan, Xiang Li, Danjun Wang, Feng Fu et Yucang Liang. « Advanced Photocatalytic Uranium Extraction Strategies : Progress, Challenges, and Prospects ». Nanomaterials 13, n^o 13 (6 juillet 2023) : 2005. http://dx.doi.org/10.3390/nano13132005.

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Nuclear energy with low carbon emission and high-energy density is considered as one of the most promising future energy sources for human beings. However, the use of nuclear energy will inevitably lead to the discharge of nuclear waste and the consumption of uranium resources. Therefore, the development of simple, efficient, and economical uranium extraction methods is of great significance for the sustainable development of nuclear energy and the restoration of the ecological environment. Photocatalytic U(VI) extraction technology as a simple, highly efficient, and low-cost strategy, received increasing attention from researchers. In this review, the development background of photocatalytic U(VI) extraction and several photocatalytic U(VI) reduction mechanisms are briefly described and the identification methods of uranium species after photocatalytic reduction are addressed. Subsequently, the modification strategies of several catalysts used for U(VI) extraction are summarized and the advantages and disadvantages of photocatalytic U(VI) extraction are compared. Additionally, the research progress of photocatalytic technology for U(VI) extraction in actual uranium-containing wastewater and seawater are evaluated. Finally, the current challenges and the developments of photocatalytic U(VI) extraction technology in the future are prospected.

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Scott, Thomas B., Geoffrey C. Allen, Peter J. Heard, Andrew C. Lewis et Darren F. Lee. « The extraction of uranium from groundwaters on iron surfaces ». Proceedings of the Royal Society A : Mathematical, Physical and Engineering Sciences 461, n^o 2057 (5 avril 2005) : 1247–59. http://dx.doi.org/10.1098/rspa.2004.1441.

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Yadav, Kartikey K., R. Vijayalakshmi et H. Singh. « Uranium from phosphoric acid : Kinetic studies of the solvent extraction processes for uranium extraction ». Desalination and Water Treatment 12, n^o 1-3 (décembre 2009) : 45–51. http://dx.doi.org/10.5004/dwt.2009.949.

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Spasic, Aleksandar M., Vaso Manojlovic et Mica Jovanovic. « Solvent extraction and entrainment problem ». Metallurgical and Materials Engineering 26, n^o 2 (22 juillet 2020) : 163–75. http://dx.doi.org/10.30544/480.

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Applications of solvent extraction operations and processes play one of the most important roles in Hydrometallurgy. Therefore, in this brief review, some general concepts for selected representative applications are discussed. Also, one particular entrainment problem solution is discussed in some more details. At first, the selected general concepts for metal production of copper and uranium from their ores are presented. Then after, the leaching-solvent extraction-electro winning process for copper is shown. Finally, the extraction of uranium from wet phosphoric acid is discussed.

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Kiegiel, Katarzyna, Grażyna Zakrzewska-Kołtuniewicz, Dorota Gajda, Agnieszka Miśkiewicz, Anna Abramowska, Paweł Biełuszka, Bożena Danko, Ewelina Chajduk et Stanisław Wołkowicz. « Dictyonema black shale and Triassic sandstones as potential sources of uranium ». Nukleonika 60, n^o 3 (1 septembre 2015) : 515–22. http://dx.doi.org/10.1515/nuka-2015-0096.

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Abstract The main objective of the present study was an assessment of the possibility of uranium recovery from domestic resources in Poland. In the first stage uranium was leached from the ground uranium ore by using acidic (sulfuric acid or hydrochloric acid) or alkaline (carbonate) solutions. The leaching efficiencies of uranium were dependent on the type of ore and it reached 81% for Dictyonemic shales and almost 100% for sandstones. The novel leaching routes, with the application of the helical membrane contactor equipped with rotating part were tested. The obtained postleaching solutions were concentrated and purified using solvent extraction or ion exchange chromatography. New methods of solvent extraction, as well as hybrid processes for separation and purification of the product, were studied. Extraction with the use of membrane capillary contactors that has many advantages above conventional methods was also proposed as an alternative purification method. The final product U3O8 could be obtained by the precipitation of ‘yellow cake’, followed by calcination step. The results of precipitation of ammonium diuranate and uranium peroxide from diluted uranium solution were presented

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Danko, Bożena, Rajmund S. Dybczyński, Zbigniew Samczyński, Dorota Gajda, Irena Herdzik-Koniecko, Grażyna Zakrzewska-Kołtuniewicz, Ewelina Chajduk et Krzysztof Kulisa. « Ion exchange investigation for recovery of uranium from acidic pregnant leach solutions ». Nukleonika 62, n^o 3 (26 septembre 2017) : 213–21. http://dx.doi.org/10.1515/nuka-2017-0031.

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Abstract The article describes studies on the separation of uranium from acid pregnant leach solutions obtained from Polish uranium ores: dictyonema shales and sandstone rocks. Ion exchange chromatography was applied for uranium sorption, using commercially available, strongly basic anion exchanger, Dowex 1. In model experiments, the influence of degree of crosslinking of Dowex 1 on the efficiency of uranium extraction was investigated. The effect of H2SO4 concentration on the breakthrough curve of uranyl ions for the Dowex 1 resins, of different crosslinking: X4, X8 and X10, was examined. Unexpectedly high increase of exchange capacity of uranium was observed in case of Dowex 1X10. This gives potential opportunity of improving the effectiveness of uranium recovery process. Applying column packed with Dowex 1X10, ‘yellow cake’ with ca. 92% yield and high purity of recovered uranium was obtained. A block diagram of the procedure for uranium and lanthanides extraction from acidic leach liquor has been proposed.

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Yacouba, Abdoul-Rachid Chaïbou, Salmana Laouali Ibrahim, Abdoul Razak Moumouni Wage et Ibrahim Natatou. « Optimization of Some Parameters on the Low Efficiency of Solvent Extraction of Uranium with Alamine 336 ». Oriental Journal Of Chemistry 37, n^o 1 (28 février 2021) : 213–20. http://dx.doi.org/10.13005/ojc/370129.

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Solvent extraction of uranium from sulfate liquor acid ore with Alamine 336 from two suppliers has been studied. The influence of various parameters, such as sulfuric acid concentration on uranium bearing solutions, concentration of Alamine 336, and concentration of uranium was investigated. The decrease of uranium efficiency extraction at the plant was caused by the degradation of the organic phase. Degradation caused by the presence of vanadium in the uranium ore. Two theoretical stages could efficiency extract more than 90% of uranium from a solution containing 3881 mg/L at O/A ratio of 1.5:1. At the range of sulfuric acid concentration of 0.1 M to 0.2 M, Uranium efficiency was enhanced from 89% to 92 at the 1st contact and from 18% to 20% at the second contact. At this range of concentration, the UO2(SO4)2/2 species predominate. For sulfuric acid concentrations over 0.2 M the uranium efficiency decreased due to the presence of UO2(SO4)2/2 and UO2(SO4)3/4 species. Improving volume percentage of Alamine 336 in organic phase enhanced the uranium efficiency to 99%.

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Duisebayeva, T., et A. Arbuz. « The use of chlorine-containing agents in the processing of spent blocks of uranium deposits ». Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 326, n^o 3 (24 février 2023) : 59–67. http://dx.doi.org/10.31643/2023/6445.29.

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The work is aimed at diversifying existing mines for the extraction and processing of natural uranium through additional processing of spent blocks of uranium deposits with chemical solutions using the method of in-situ well leaching (ISL) in order to extract associated useful components. A feature of this technology is the use of the existing production infrastructure for the extraction of associated useful components in existing uranium mines, without significant capital investments in production infrastructure and mining operations. The technology of underground borehole leaching has been reliably developed in uranium deposits for decades. The fundamental similarity of the technology for the extraction of uranium and a number of associated useful components (APC) - by the ISR method, allows the use of spent ore fields of uranium deposits for the extraction of PPC. The use of ready-made technological infrastructure (wells, pipeline network, pumping equipment, control units, etc.) allows, due to savings on infrastructure costs, to obtain profitability when mining ore-bearing blocks with a content of recoverable components from ≤ 1 g/t, up to 0.1 g/t. Taking into account the indirect savings of significant costs for the reclamation of spent blocks, it will be profitable to mine blocks with a content of recoverable components up to 0.01 g/t. In view of the foregoing, this technology has a good prospect for implementation in production.

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Kanka, Lukas, et Jiri Janda. « Liquid-liquid extraction of Am(III), Pu(IV), and U(VI) using malonamide and tributyl phosphate in room temperature ionic liquids as diluent ». Nuclear Technology and Radiation Protection 39, n^o 2 (2024) : 138–45. http://dx.doi.org/10.2298/ntrp2402138k.

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The extraction behavior of americium, plutonium, and uranium from nitric or hydrochloric acidic medium by a solution of malonamide or tributyl phosphate in trioctylmethylammonium chloride (Aliquat 336) or trihexyl(tetradecyl)phosphonium chloride (Cyphos 101) ionic liquids were studied. The extraction percentage of these actinides was measured as a function of a concentration of nitric or hydrochloric acid and a set combination of a room temperature ionic liquid and an extractant. The pure room temperature ionic liquids could extract the plutonium and uranium to various degrees, with the combinations with extractants affecting the extraction percentages further. The 100 % extraction efficiency of plutonium was achieved across all concentrations of HCl with the combinations of Cyphos 101 and malonamide. 100% extraction efficiency of uranium was achieved by Cyphos 101 and malonamide from distilled water. Americium was not extracted by any combination under any conditions.

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Nursapina, Nurgul, Fatima Meiirman, Gulsana Amanova et Ilona Matveyeva. « Study of effectiveness of strongly basic anion exchange resins in the process of uranium extraction from the underground leaching productive solution ». Chemical Bulletin of Kazakh National University, n^o 4 (28 décembre 2018) : 10–15. http://dx.doi.org/10.15328/cb979.

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The process of uranium sorption is one of the important stages in the production of uranium. This stage affects uranium extraction effectiveness from productive solutions. The sorption and desorption characteristic of anion exchange resins in dynamic condition were investigated in order to study the effectiveness of resins, which were used for extraction of uranium from sulfuric acid productive solution. The sorption and desorption of uranium from the productive solution on anion exchange resins AB-17 and DOWEX 1X8 200 was carried out in laboratory conditions. The sorption characteristics were investigated. The determined sorption capacities of the resins were 1.47 and 14.4 mg/mL, respectively. The most efficient anion exchanger is DOWEX 1X8 200 that has a high sorption capacity as well as good desorption characteristics, which make it possible to obtain solutions having 23 times higher uranium concentrations than in productive solutions.

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Duisebayeva, T. S., et A. S. Arbuz. « Prospects for use of chlorine-containing leaching solutions for extraction of associated useful components from spent ores of uranium deposits ». Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 4, n^o 319 (28 octobre 2021) : 25–31. http://dx.doi.org/10.31643/2021/6445.37.

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Work aimed at diversification of production through the additional extraction of associated useful components at uranium mines. The peculiarity of the work carried out is the additional processing of spent uranium mines at the existing ones using the existing production infrastructure for the extraction of associated useful components. The technology of underground leaching is well developed for uranium deposits. The leaching of associated useful components differs from the leaching of uranium only in the reagents used, and they are fundamentally similar to the method of underground-borehole leaching. Even if there are associated components in the uranium-bearing sands with a content of less than 1 g/t, up to 0.1 g/t production can be profitable. The use of ready-made infrastructure of uranium mines on spent blocks of deposits allows us to expect positive economic profitability in the future.

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Li, Guihe, et Jia Yao. « A Review of In Situ Leaching (ISL) for Uranium Mining ». Mining 4, n^o 1 (2 mars 2024) : 120–48. http://dx.doi.org/10.3390/mining4010009.

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Uranium, a cornerstone for nuclear energy, facilitates a clean and efficient energy conversion. In the era of global clean energy initiatives, uranium resources have emerged as a vital component for achieving sustainability and clean power. To fulfill the escalating demand for clean energy, continual advancements in uranium mining technologies are imperative. Currently, established uranium mining methods encompass open-pit mining, underground mining, and in situ leaching (ISL). Notably, in situ leaching stands out due to its environmental friendliness, efficient extraction, and cost-effectiveness. Moreover, it unlocks the potential of extracting uranium from previously challenging low-grade sandstone-hosted deposits, presenting novel opportunities for uranium mining. This comprehensive review systematically classifies and analyzes various in situ leaching techniques, exploring their core principles, suitability, technological advancements, and practical implementations. Building on this foundation, it identifies the challenges faced by in situ leaching and proposes future improvement strategies. This study offers valuable insights into the sustainable advancement of in situ leaching technologies in uranium mining, propelling scientific research and practical applications in the field.

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Smith, Steven C., Matthew Douglas, Dean A. Moore, Ravi K. Kukkadapu et Bruce W. Arey. « Uranium Extraction From Laboratory-Synthesized, Uranium-Doped Hydrous Ferric Oxides ». Environmental Science & ; Technology 43, n^o 7 (avril 2009) : 2341–47. http://dx.doi.org/10.1021/es802621t.

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Ohashi, Yusuke, Shinji Murashita et Mitsuo Nomura. « Extraction of uranium from solid waste containing uranium and fluorine ». Minerals Engineering 61 (juin 2014) : 32–39. http://dx.doi.org/10.1016/j.mineng.2014.03.003.

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Zhang, Biao, Mi Li, Xiaowen Zhang et Jing Huang. « Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching ». JOM 68, n^o 7 (23 mai 2016) : 1990–2001. http://dx.doi.org/10.1007/s11837-016-1952-8.

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Malov, Alexander I., Sergey B. Zykov et Alexey S. Tyshov. « Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction ». Minerals 11, n^o 5 (29 avril 2021) : 467. http://dx.doi.org/10.3390/min11050467.

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The sequential extraction procedure is used to reconstruct the processes of redistribution of uranium isotopes in the mineral phases of the aquifer of the Vendian sandy-argillaceous deposits developed in the coastal territory of the European North of Russia. This aquifer has large resources of drinking and mineral groundwater which, however, are used in extremely limited quantities. This is due to the very complex nature of the hydrochemical conditions, and uranium-isotopic methods are used to clarify these conditions. The following mineral phases of core samples were characterized: adsorbed trace materials and carbonate minerals; ferrihydrate, amorphous minerals of Fe, Al and Si, and secondary U minerals; crystalline iron minerals; clay and some refractory minerals; and all remaining resistant minerals. The most resistant minerals, whose fraction ranges from 70.58 to 96.4%, have a minimum average uranium concentration of 0.47 ppm. This uranium is practically conserved in the rock, as a result of which the average ratio of its 234U:238U isotopes is close to equilibrium. In the remaining fractions, uranium is redistributed by groundwater along their flow lines from recharge areas in watersheds to areas of discharge into river valleys. Its maximum concentration (12.89 ppm) measurement is carried out by coprecipitation with iron hydroxides, then the uranium is adsorbed and precipitated with carbonates (9.14 ppm). The average 234U:238U is maximum in adsorbed trace materials and carbonate minerals (2.39 ± 0.36) and is close to that in fresh groundwater (2.8 ± 0.42). It is also increased in the amorphous minerals of Fe (1.53 ± 0.23). In general, there is a dependence of the 234U:238U activity ratio in rock on the degree of participation of groundwater in the deposition of hydrogenic uranium isotopes into the cracks and pores of these rocks. The results obtained contribute to the refinement of such a parameter as the retardation factor, which is necessary for understanding the processes of migration and concentration of uranium in sedimentary basins.

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Xia, Yu, Chuanlong Mou et Hao Wu. « Uranium Occurrence State and Its Implication for Sandstone-Type Uranium Mineralization within the Hanbazhai Area of the Longchuanjiang Basin, China ». Minerals 13, n^o 8 (3 août 2023) : 1037. http://dx.doi.org/10.3390/min13081037.

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The Mangbang Formation in the Hanbazhai area is part of the uranium ore field in the Longchuanjiang Basin, China. Uraniferous sandstones from this formation are examined in this study. The type and mode of occurrence of uranium are investigated in detail using an experiment for the sequential extraction of uranium, as well as an electron probe, scanning electron microscopy, and energy spectrum analyses. The sequential extraction experiment indicates that the proportion of uranium minerals is significantly greater than that of the adsorbed uranium in the samples, with the latter being largely present in framboidal pyrites and clay minerals. The results show that these uranium minerals are mainly composed of coffinite and uranium phosphosilicates, which closely coexist with framboidal pyrites, carbon debris, feldspar minerals, and clay minerals. The discovery of coffinite and uranium phosphosilicates is discussed in context with their symbiotic relationship and geochemical environment. Uraniferous sandstones are considered to have undergone at least two stages of mineralization: the sedimentary–diagenetic stage and the later uranium enrichment by fluid. The geochemical environment of the sedimentary–diagenetic stage is generally a sulfide-reducing environment, and the later fluids are rich in U, Si, P, and Y.

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Ovseychuk, V. « Dependence of uranium extraction into solution during heap leaching on the petrographic composition of ores ». Transbaikal State University Journal 27, n^o 7 (2021) : 27–32. http://dx.doi.org/10.21209/2227-9245-2021-27-7-27-32.

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The widespread introduction of physical and chemical geotechnologies in the production of mineral raw materials makes it possible to involve ores that are poor in the content of the useful component, which are unprofitable to work out using traditional physical and technical methods. One of these new geotechnologies is the heap leaching of rocky uranium ores. When planning the volume of output of finished products, it is necessary to have an analytical apparatus that would make it possible, using the acquired knowledge, to calculate the required volume of mineral raw material production and its varietal composition. Based on their task, studies were conducted on the qualitative and quantitative characteristics of ores that affect the indicators of extraction of useful components from them. As a result of the research, the dependence of the index of uranium extraction into a productive solution during infiltration of sulfuric acid leaching on the material composition of ores was established. Ores localized in various lithological differences of acidic, medium and basic rocks were tested: granites, felsites, trachydacites, andesites and conglomerates. The ores were classified according to the size of the piece with the allocation of fineness classes +200 mm, -200 +150 mm, -150 + 100 mm, -100+70 mm, -70+ 30 mm, -30 mm. The tests were carried out in laboratory and semi-industrial conditions. The maximum extraction was obtained for the class – 30 mm in columns. When leaching in stacks, the maximum extraction of uranium into the solution was obtained for the size class -70+30 mm. The reason for the lower extraction from the -30 mm class during leaching in semi-industrial conditions was the processes of mechanical colmatation, due to the large number of fine fractions. The criterion characterizing the material composition of ores is the content of silica (SiO2). During the tests, the dependence of the uranium extraction coefficient in the productive solution on the content of silica in the ores was established. The higher the concentration of silica, the more uranium passes into the productive solution during leaching with a stable composition of uranium mineralization. The dependence is described by a mathematical formula, which allows us to use it to calculate the extraction of uranium into a productive solution, knowing the material composition of ores

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Dressler, Aline, Antoine Leydier et Agnès Grandjean. « Effects of Impregnated Amidophosphonate Ligand Concentration on the Uranium Extraction Behavior of Mesoporous Silica ». Molecules 27, n^o 14 (6 juillet 2022) : 4342. http://dx.doi.org/10.3390/molecules27144342.

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A series of solid-phase uranium extractants were prepared by post-synthesis impregnation of a mesoporous silica support previously functionalized with octyl chains by direct silanization. Five materials were synthesized with 0, 0.2, 0.3, 0.4 and 0.5 mmol of the amidophosphonate ligand DEHCEBP per gram of functionalized solid, and the effect of the ligand concentration on the uranium extraction efficiency and selectivity of the materials was investigated. Nitrogen adsorption–desorption data show that with increasing ligand loadings, the specific surface area and average pore volume decrease as the amidophosphonate ligand fills first the micropores and then the mesopores of the support. Acidic uranium solutions with a high sulfate content were used to replicate the conditions in ore treatment leaching solutions. Considering the extraction kinetics, the equilibration time was found to increase with the ligand concentration, which can be explained by the clogging of micropores and the multilayer arrangement of the DEHCEBP molecules in the materials with their highest ligand contents. The fact that the equilibrium ligand/uranium ratio is about 2 mol/mol regardless of the ligand concentration in the material suggests that all the ligand molecules remain accessible for extraction. The maximum uranium extraction capacities ranged from 30 mg∙g−1 at 0.2 mmol∙g−1 DEHCEBP to 54 mg∙g−1 in the material with 0.5 mmol∙g−1 DEHCEBP. These materials could therefore potentially be used as solid-phase uranium extractants in acidic solutions with high sulfate concentrations.

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Scheiflinger, Florian, Marzieh Habibi, Elham Zeynolabedini, Christof Plessl et Gabriele Wallner. « Radionuclide extraction with different ionic liquids ». Journal of Radioanalytical and Nuclear Chemistry 322, n^o 3 (28 septembre 2019) : 1841–48. http://dx.doi.org/10.1007/s10967-019-06807-z.

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Abstract 10 ionic liquids based on 3 different cations and 5 anions were investigated for radionuclide extraction from aqueous solutions. While uranium and 210Po were extracted with satisfying yields irrespective of the feed solution pH, 234Th, 226Ra and 210Pb extraction yields were rather low. The contact time necessary for near to complete extraction was determined as well as the conditions for successful back-extraction. The loading capacities of the ionic liquids for uranium were very high and depended on the uranyl counter-ion. From the leaching of the ionic liquids into the aqueous phase the predominant extraction mechanisms were derived.

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Anggraini, Mutia, Fuad Wafa Nawawi et Kurnia Setiawan Widana. « Penentuan Kondisi Optimum Proses Ekstraksi Uranium dan Torium dari Terak II Timah dengan Metode Pelindian Asam Sulfat dan Solvent Extraction Trioctylamine (TOA) ». EKSPLORIUM 40, n^o 1 (31 juillet 2019) : 11. http://dx.doi.org/10.17146/eksplorium.2019.40.1.5378.

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ABSTRAKTerak II timah merupakan produk hasil samping dari peleburan timah tahap kedua. Terak II timah ini mengandung unsur bernilai ekonomi tinggi berupa unsur radioaktif (uranium dan torium) dan logam tanah jarang (rare earth element). Unsur-unsur tersebut dapat dimanfaatkan apabila telah terpisah satu dengan lainnya. Proses pemisahan unsur radioaktif dan unsur logam tanah jarang telah dilakukan dengan metode pelindian asam sulfat. Hasil proses ini adalah endapan yang mengandung logam tanah jarang dan filtrat yang mengandung unsur radioaktif berupa uranium dan torium sulfat. Penelitian terkait pemisahan uranium dan torium hasil pengolahan terak II timah hanya sedikit dipublikasikan. Paper ini bertujuan untuk mengetahui efektifitas proses pemisahan uranium dan torium dengan metode solvent extraction menggunakan trioctylamine (TOA). Proses solvent extraction dilakukan dengan memvariasikan konsentrasi TOA yang digunakan, perbandingan fase aqueous dan fase organik (A/O) dan variasi waktu ekstraksi. Pada penelitian ini diperoleh kondisi optimum proses yaitu konsentrasi TOA 4%, perbandingan A/O 1 : 1, dan waktu pencampuran aqueous dan organik selama 2 menit. Pada kondisi ini uranium dan torium yang terekstrak masing-masing sebanyak 67% dan 0,84%. ABSTRACTTin slag II is a by-product of the second stage of tin smelting. The tin slag II contains high economic value elements in the form of radioactive elements (uranium and thorium) and rare earth elements. These elements can be utilized if they are separated from each other. The process of separating radioactive elements and rare earth elements has been carried out by leaching sulfuric acid method. The results of this process are residue containing rare earth elements and filtrates containing radioactive elements in the form of uranium and thorium sulfate. Research related to the separation of uranium and thorium sulfate in tin slag processing is only slightly published. This paper aims to determine the effectiveness of the uranium and thorium separating process by the solvent extraction method using trioctylamine (TOA). The solvent extraction process is carried out by varying the concentration of TOA used, comparison of the aqueous and organic phase (A/O) and variations in extraction time. In this study, the optimum conditions for the process were obtained at 4% of TOA concentration, 1 : 1 of A/O ratio, and mixing time of aqueous and organic phase for 2 minutes. In this condition, uranium and thorium which extracted were 67% and 0.84% respectively.

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