Extraction Of Thorium Research Articles

Advancing Rare-Earth (4f) and Actinide (5f) Separation through Machine Learning and Automated High-Throughput Experiments.

Identifying improved and sustainable alternatives to "classic" separation techniques is an active research field due to its potential widespread impact in fundamental and applied chemistry. As basic purification methodologies, like liquid-liquid extraction, undergo continuous refinement by chemists and engineers, identifying new conditions that outperform existing techniques can be difficult. A major contributor to this challenging problem is the need to explore a vast experimental space to identify the precise conditions that optimize the separation procedure. The advent of artificial intelligence and the advancement of robotic technologies offer the potential to shift the traditional design paradigm. Toward that end, we applied a combination of Bayesian Optimization and high-throughput robotic experiments on the liquid-liquid extraction of thorium (Th4+) and demonstrated that this approach speeds up discovery and significantly accelerates the optimization process. By using Bayesian Optimization as a guide, our automated instrument carried out a total of 339 distribution ratio measurements, corresponding to 113 unique conditions, identifying the optimal experimental conditions with reduced experimental efforts by an estimated 74% compared to a traditional full screening approach. This time and cost saving is particularly significant for radioactive materials, as it not only is more economical and sustainable but also minimizes human exposure to radioactivity.

Extraction and purification of thorium and rare earth elements from bastnaesite mineral: a comprehensive leaching and precipitation study

Extraction and purification of thorium and rare earth elements from bastnaesite mineral: a comprehensive leaching and precipitation study

Optimization of thorium solvent extraction process from feed solution with Cyanex 272 by response surface methodology (RSM)

Due to the limited reserves of uranium, the abundance of thorium compared to it and other advantages, the development of the thorium fuel cycle is of interest in different countries. The optimization of thorium extraction from a feed solution produced by Saghand ore with bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) on a laboratory scale was evaluated by response surface method. The operating variables include Cyanex 272 concentration of 0.001 to 0.2 mol/L, pH of 0 to 2, equilibrium time of 5 to 60 min and aqueous to organic phase ratio of 0.5 to 2.5 were conducted. The value of R2 = 0.9695 and an error of less than 4% indicate the validity of the model. Therefore, the model is in good agreement with the experimental results. It can be said that there are significant interactions between operational parameters, which vindicate different feedbacks of the system in different operational conditions. The results showed that the 4 mol/L sulfuric acid was a suitable agent for recovering thorium ions from the loaded organic phase. In optimum conditions, the thorium purity percentage and thorium stripping efficiency were obtained 98.99 and 94.12%, respectively.

Adsorption of thorium (IV) from aqueous solutions using mesoporous TiO2: Kinetics, isotherm and thermodynamics

Thorium is considered as a promising resource for the production of nuclear power, with its abundance in the Earth's crust offering potential for sustainable energy generation to fulfill upcoming energy needs. As a fertile material, thorium has the capability to be converted into fissile uranium-233, which is essential for sustaining nuclear chain reactions. Therefore, the extraction of thorium from the Earth's crust is imperative for its utilization as fuel in nuclear reactors. This study presents the synthesis of titanium dioxide with a mesoporous structure using the solvothermal method for extracting Th(IV) from aqueous solutions. Batch adsorption experiments were carried out to evaluate the impact of solution pH, adsorption kinetics, adsorbent dosage, initial Th(IV) concentration, and temperature. The adsorption process is influenced by the pH, showing a maximum adsorption capacity of 101.4 mg per gram of mesoporous TiO2 adsorbent (MTA) at an initial Th(IV) concentration of 400 mg L−1 at pH 4.0. Results indicate a significant correlation with the pseudo-second-order and Freundlich adsorption isotherm models. Temperature-dependent investigations revealed that the adsorption of Th(IV) is spontaneous at room temperature and increases with higher temperatures (endothermic process). Moreover, the study highlights the rapid kinetics of Th(IV) adsorption by MTA, making it a favorable choice for upscaling the extraction process of Th(IV). In conclusion, the results suggest MTA as a promising adsorbent for the removal of Th(IV) from aqueous solutions.

Synthesis of phosphonic acid and amide functionalized core–shell magnetic composite and its mechanisms for synergistic adsorption of thorium from strongly acidic solution

To develop adsorbents for the preeminent extraction of thorium in strongly acidic solutions is very imperative, due to strong inorganic acids are frequently used in the fuel cycle of thorium. Herein, a robust core–shell magnetic nanocomposite Fe3O4@SiO2/P (MBA-VPA-AM) possessing phosphonic acid and amide was developed via distillation-precipitation copolymerization of N, N'-methylene diacrylamide (MBA), vinylphosphonic acid (VPA) with acrylamide (AM) employing Fe3O4 decorated by SiO2 (Fe3O4@SiO2) as magnetic core. Due to the synergistic effect of phosphonic acid and amide ligand, the sorbent could capture thorium from concentrated HNO3 media efficiently, and the maximum adsorption capacity (qmax) at 4 mol L−1 of HNO3 solution reached up to 232.5 mg g−1, superior to that of all magnetic sorbents reported previously. Furthermore, the sorbent displayed good selectivity towards thorium in the presence of competitive metal ions including La3+, Nd3+, and Ce3+. The excellent thorium sorption behavior in strong hydrogen nitrate solution was merely ascribed to the complexation of thorium with phosphonic acid ligand, and the amide ligand could not complex with thorium, evidenced by XPS, FT-IR and DFT method. However, the presence of amide ligand could enhance the hydrophilicity of the sorbent and the free movement degree of phosphonic acid ligand to a certain extent, both of which could help to promote the thorium sorption on the sorbent in strong HNO3 media. Besides, due to its core–shell structure and superparamagnetism, the sorbent not only exhibited excellent acidic resistance in strong acid medias, but could be magnetically recouped, which could avoid tedious centrifugation or filtration of traditional adsorbents. This work provides a novel strategy to develop magnetic sorbent for the preeminent entrapment of thorium from strong acid solutions.

Eco-friendly technology for “Nitrofos” fertilizer obtained from radioactive man-made waste

The article presents the results of research into the process of purification of phosphoric acid from radioactive isotopes after extraction of uranium, thorium, and REE. It is shown that the main purification of acid is achieved in the process of gypsum precipitation with sulfuric acid and barium nitrate. Additional purification of nitrate-phosphate solution is achieved after uranium extraction and sorption-extraction purification of REE. The sorption raffinate with a concentration of P2O5 25 g/L, REE 0.5 g/L and NH4NO3 300 g/L were used for fertilizer production. Additional purification of NH4NO3 solution from isotopes 226Ra, 210Po, 227Ac is achieved in the process of REE extraction purification. The aggregate of all refining processes of purification of nitrate-phosphate solution from radioactive isotopes provided NP-fertilizer “Nitrofos”, which meets the quality standards. Extraction of P2O5 from raw materials into NP-fertilizer – 90%; extraction of REE from raw materials into collective chemical concentrate – 95%; direct commercial extraction of REE from raw materials into the product – 85%.

A ciprofloxacin derived task specific ionic liquid as a highly selective extractant of thorium versus uranium

Highly selective extraction of thorium versus uranium using a TSIL system.

TBP-Impregnated Siplite LX-16 Polymeric Resin for Thorium Extraction from Nitrate Medium, Part A: Preparation and Extraction Performance

TBP-Impregnated Siplite LX-16 Polymeric Resin for Thorium Extraction from Nitrate Medium, Part A: Preparation and Extraction Performance

A sustainable strategy for targeted extraction of thorium from radioactive waste leachate based on hydrophobic deep eutectic solvent

In this work, the new hydrophobic deep eutectic solvents (HDESs) based on 2-hexyldecanoic acid (HDA) as a hydrogen bond donor (HBD) were used to selectively enrich trace Th from radioactive waste leach solution. These HDESs are characterized by low toxicity, bio-friendliness, low viscosity and sufficient hydrophobicity. Compared with Al, Mg, Ca and RE, HDESs exhibited exceptional selectivity for Th extraction, along with high loading capacity, easy stripping and stable reusability. The mechanism of Th extraction by the HDES is a cation exchange reaction. Based on the thymol (TL):HDA (1:3) HDES, a short flow closed-loop recovery process of Th in the leach solution of radioactive waste residue was developed. After a single-step extraction, the extraction percentage (E%) of Th exceeded 98.0%, while the E% of other elements was less than 0.14%. After stripping, the concentration of Th in the concentrated solution reached 2.16 × 103 mg/L with a purity of 74.2%, which could be directly used for subsequent purification. By adjusting the pH to 4.00, the raffinate was used as a feed solution for RE elements recovery. The HDES-based extraction strategy for Th is simple, safe, efficient and environmentally friendly, providing a new idea for the recovery of radioactive waste residues.

Extraction of thorium (IV) ions utilizing cinnamon bark via fixed-bed adsorbent

Extraction of thorium (IV) ions utilizing cinnamon bark via fixed-bed adsorbent

Selective Extraction of Thorium(IV) from Uranium and Rare Earth Elements Using Tetraphenylethane-1,2-diylbis(phosphoramidate).

Tetraphenylethane-1,2-diylbis(phosphoramidate) in conjugation with a room temperature ionic liquid in chloroform medium is reported for the first time in the liquid-liquid extraction of thorium (Th). The extracted Th(IV) is collected as a white solid in the organic medium, thereby facilitating its easy separation. A high distribution ratio (D) of (12.4 ± 0.1) × 103 in 2-8 mol L-1 acidity range and high decontamination factors (α) of Th(IV) from uranium, lanthanides, and a number of transition elements makes this extraction process versatile and selective. A number of experimental investigations in synergism with extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) studies are interpreted to confirm the structure of the chelated complex. A 1:2 metal/ligand complex in which the two oxygen and two nitrogen atoms of each bis(phosphoramidate) molecule satisfying the eight coordination sites of Th(IV) is found to be formed. The extracted white solid thorium complex is easily converted to ThO2 after washing and heating at 1300 °C under O2 atmosphere. This work is expected to find direct application in the thorium fuel cycle, especially in the mining process of thorium from its ores and in the separation of fissile 233U from fertile 232Th in irradiated fuel.

A sulfonated ligand-aqueous two-phase system for selective extraction of thorium from mining wastewater: Process optimization, structural characterization and mechanism exploration

As a potential nuclear fuel, the recovery of thorium with high efficiency, high selectivity and high extraction capacity from thorium-containing wastewater is considered to be one of the effective ways to reduce pollution and solve the shortage of thorium resources. However, the problem of efficient and selective separation of thorium from the complex environment has not been completely solved. Herein, a functional ligand called arsenazo (ASA), polyethylene glycol, and sodium sulphate were used to construct an aqueous two-phase system (ATPs) for the selectivity extraction and separation of thorium from mining wastewater. Furthermore, the complex agent, pH value, temperature, equilibrium time, coexisting substances, and other conditions for the extraction and separation of thorium were optimized, indicating that 98.7 % of thorium was efficiently and precisely separated from the acid-leaching solution to the pH of 2–3 or 5–6 with 0.08 g/L of ASA within 10 min, and the interference with multiple coexisting ions and organic substances was avoided. Importantly, the analysis of water quality parameters, thermogravimetry, infrared spectroscopy, and ultraviolet–visible spectroscopy revealed the coordination relationship between thorium ions and complex agents, indicating that the extraction of thorium in the aqueous two-phase system was a cation exchange mechanism. More importantly, SEM, TEM, EDX, and XRD verified that thorium was efficiently and selectively separated by a sulfone acid ligand-aqueous two-phase system, providing quantitative information on thorium-containing product distribution of relatively high accuracy and avoiding the interference with coexisting substance. Therefore, this work provided theoretical guidance on treating and reusing thorium in wastewater and enriched the content of functional ligand-aqueous two-phase extraction systems in green production technology.

Determination of optimum conditions for the extraction and separation of lanthanum, cerium, yttrium and thorium using Taguchi method

Determination of optimum conditions for the extraction and separation of lanthanum, cerium, yttrium and thorium using Taguchi method

Extraction and complexation mechanism of uranium(VI) and thorium(IV) by tetradentate phenanthroline phosphonate (POPhen) ligands

The extraction and separation of actinide over lanthanide elements is a key step in the spent fuel reprocessing process, which involves a variety of actinides with different valence states. The phenanthroline phosphonate (POPhen) extractants have a strong ability to extract trivalent actinides over lanthanides from highly acidic HNO3 solution with good separation ability of An(III) over Ln(III). However, the extraction properties and complexation mechanism of POPhen extractants for high-valence actinides have yet to be studied. In this work, U(VI) and Th(IV) were selected as representatives of high-valence actinides to systematically study the extraction effect and complexation mechanism of C2-POPhen and C4-POPhen with them. The results showed that POPhen extractants had excellent coordination and extraction ability for U(VI) and Th(IV) under highly acidic nitrate conditions. The extraction capacity of C4-POPhen was stronger than that of C2-POPhen, and both ligands hold a stronger extraction capacity for Th(IV) than U(VI) under the same experimental conditions. Both the slope analysis and spectroscopic studies indicated that POPhen extractants could form the sole 1:1 complexes with U(VI) and both 1:1 and 1:2 metal-to-ligand complexes with Th(IV). The structures of the 1:1 and 1:2 Th(IV) complexes with POPhen-type extractants were first elucidated by X-ray crystallography. This study will be helpful to deepen the understanding of the extraction effect and complexation mechanism of POPhen with high-valence actinide elements, providing a fundamental data basis and theoretical reference for the development of the advanced subsequent actinides separation process.

Application of Poly(caffeic acid) for the Extraction of Critical Rare Earth Elements.

Poly(caffeic acid) was synthesized and utilized for the extraction and determination of rare earth elements (REEs), thorium, and uranium. Oxidative polymerization of caffeic acid, a low-cost plant-based material, in the presence of ethylenediamine produced a granular, air-stable, and cross-linked polymer. The polymer is highly oxygenated and together with the amino group from ethylenediamine efficiently coordinates and preconcentrates these critical elements from aqueous media. Extraction was dependent on solution pH, amount of sorbent, and extraction time, while the concentration and flow rate of the desorption solution governed the recovery efficiency. Removal and recovery efficiencies greater than 98 and 90%, respectively, and low levels of detection ranging from 0.1 to 2.9 ng/L were achieved. Determination of these strategic elements in the presence of potentially interfering ions as well as in complex matrices such as well water and produced water samples also was demonstrated. The capacity of poly(caffeic acid) was determined with lanthanum as a representative REE to be 161.7 mg/g, establishing the promise of poly(caffeic acid) for larger-scale extractions in addition to the ability to screen sources for the presence of REEs.

Extraction and separation of thorium from cerium and lanthanum by Cyphos® IL 101 ionic liquid

Extraction and separation of thorium from cerium and lanthanum by Cyphos® IL 101 ionic liquid

Extraction of Actinides and Lanthanides(III) from Nitric Acid Solutions with Mixtures of N-(Diphenylphosphoryl)-N'-propylureas with ω-Nitrogen-Containing Groups and Dinonylnaphthalenesulfonic Acid

Extraction of uranium, thorium, and lanthanide(III) ions from nitric acid solutions with mixtures of dinonylnaphthalenesulfonic acid and N-(diphenylphosphoryl)-N'-n-propylureas containing imidazolyl, diethylamino, pyrid-2-yl, and 2-oxopyrrolidine fragments has been studied in organic solvents. Considerable synergetic effect on extraction of metal ions with mixtures of dinonylnaphthalenesulfonic acid and N-(diphenylphosphoryl)-N'-[3-(2-oxopyrrolidino)propyl]urea has been revealed. Stoichiometry of extracted complexes has been determined. Effect of extractant strucuture, organic diluent nature, and HNO3 content in aqueous phase on extraction efficiency of metal cations into organic medium has been accessed.

Synergistic extraction and separation of thorium from rare earths in chloride media using mixture of Cextrant 230 and Cyanex 923

In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230, the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated. The maximum synergistic enhancement coefficient (R) of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/ Cyanex 923. The synergistic extracted species of Th4+ is determined as ThCl4·2Cextrant 230·Cyanex 923. The synergistic extraction of Th4+ is an entropy-driven exothermic process. The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L (calculated as ThO2), and the loaded thorium in the organic phase can be effectively stripped by distilled water. For comparison, rare earth cations are barely extracted under the similar conditions, suggesting that the mixtures can be applied to separate thorium from rare earths. A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite. The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to 1.4 μg/L by 3 stages of extraction, which is superior to sole Cextrant 230 or Cyanex 923. The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity, implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.

Biosorption of some elements by algae from a cutinite-rich coal and its effect on organic geochemical composition: A case study from Abu Thora, Sinai, Egypt

A Carboniferous-age unique cutinite-rich coal seam at Wadi Abu Thora in Sinai, Egypt, was subjected to biosorption extraction of uranium (U) and thorium (Th) by five native algal species. These algal species were used in the biosorption process with the coal acting as a cultivation substrate. The concentration of U and Th was measured before and after the biosorption process. The five algal species used included Sarconema filofirms, Ulva Lactuca, Sargassum detofiulum, Caulerpa prolifera, and Cystoseira osmundacea, in addition to the yeast Saccharomyces cerevisiae. Two species, namely Caulerpa prolifera and Cystoseira osmundacea, were able to grow and adhere well to the coal particles as indicated by the microscopic examination in fluorescence mode. The above two species showed a capability to biosorb U and Th completely followed by Sarconema filofirms (56.7%, 18.7 ppm), Ulva Lactuca (49.4%, 16.3 ppm), and Sargassum detofiulum (40.3%, 13.3 ppm). These three species were successful in the uptake of U, alongside Saccharomyces cerevisiae, which showed a greater capability (58.2% or 19.2 ppm U). Biosorption by Caulerpa prolifera and Cystoseira osmundacea algae is an effective procedure to extract U and Th from this coal. Coal macerals played an important role in U precipitation, reflecting the structure of the compound that contains the U. Extraction of U and Th by biosorption resulted in changes in the cutinite-rich coal sample. Geochemical evaluation of the treated samples reflects a change in their chemical structure with the partial or complete removal of carboxyl/carbonyl-only groups in addition to the n-alkane chains. Pyrolysis data indicated shorter n-alkane-alkene compounds and smaller ratios. Data show that algae play a role in the biotransformation of absorbed organic matter composition by type and quantity. Finally, these compositional changes may produce more mature organic matter from the parent sample.

Selective extraction of thorium to directly form self-assembly solid from HNO3 solution

Based on ions exchange between [DMDSA]+[Cl]- (Dimethyl distearyl ammonium chloride) and N,N-dialkyl-succinamide acid (SCA), three novel bifunctional [DMDSA]+[SCA]- ionic liquids (ILs) were firstly synthesized for extraction of thorium (IV) by self-assembly strategy. The simultaneous extraction and solidification of Th(IV) were unexpectedly realized in one-step operation using the present ILs in HNO3 solution, and more than 99% thorium (IV) was enriched and immediately aggregated into self-assembly solid at the biphasic interface. The self-assembly solid was further identified by FT-IR, SEM with element mapping EDS and XPS analysis, and revealing that the self-assembly extraction (SAE) was triggered by the amphiphilic [DMDSA]+ cations. A three-step extraction mechanism dominated by [SCA·Th(NO3)4]- was proposed based on the slope analysis method and HRMS analysis. The self-assembly extraction of Th(IV) exhibited the extremely excellent selectivity in the presence of U(VI) and typical lanthanide elements including La(III), Eu(III) and Lu(III), and the separation factors reached 2516 for Th/U, 1885 for Th/La, 1512 for Th/Eu and 558 for Th/Lu, respectively. The proposed SAE strategy was proved to be an efficient method for one-step separation and solidification of thorium ions from U(VI) and/or lanthanides.