Extraction Of Thorium Research Articles

Recovery of Uranium, Thorium, and Other Rare Metals from Eudialyte Concentrate by a Binary Extractant Based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and Methyl Trioctylammonium Nitrate

Eudialyte-group minerals are of scientific interest as important concentrators of rare elements (mainly Zr and REE) in agpaitic alkaline rocks and a potential source of REE, Zr, Hf, Nb, and Ta for industrial use. Extraction of uranium(VI), thorium(IV), zirconium(IV), hafnium(IV), titanium(IV), and scandium(III) by a binary extractant based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyl trioctylammonium nitrate from eudialyte breakdown solutions is studied. Extraction isotherms were obtained and exhaustive extraction was investigated. It is shown that uranium, thorium, hafnium, zirconium, scandium, and titanium are almost completely recovered in two-stage extraction by a mixture of 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyltrioctylammonium nitrate in 1,2-dichloroethane. Quantitative characteristics were compared for uranium(VI), thorium(IV), zirconium(IV), hafnium(IV), titanium(IV), and scandium(III). It was shown that the extraction efficiency of the metals by the binary extractant based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyltrioctylammonium nitrate in 1,2-dichloroethane is much higher in comparison with the commercially available tributyl phosphate.

Aggregation Behavior of Nitrilotriacetamide (NTAmide) Ligands in Thorium(IV) Extraction from Acidic Medium: Small-Angle Neutron Scattering, Fourier Transform Infrared, and Theoretical Studies.

Two tripodal amides obtained from nitrilotriacetic acid with n-butyl and n-octyl alkyl chains (HBNTA(LI) and HONTA(LII), respectively) were studied for the extraction of Th(IV) ions from nitric acid medium. The effect of the diluent medium, i.e., n-dodecane alone and a mixture of n-dodecane and 1-decanol, onto aggregate formation were investigated using small angle neutron scattering (SANS) studies. In addition, the influence of the ligand structure, nitric acid, and Th(IV) loading onto ligand aggregation and third-phase formation tendency was discussed.The LI/LII exist as monomers (aggregarte radius for LI: 6.0 Å; LII:7.4 Å) in the presence of 1-decanol, whereas LII forms dimers (aggregarte radius for LII:9.3 Å; LI does not dissolve in n-dodecane) in the absence of 1-decanol. The aggregation number increases for both the ligands after HNO3 and Th(IV) loading. The maximum organic concentration (0.050 ± 0.004 M) of Th(IV) was reached without third-phase formation for 0.1 M LI/LII dissolved in 20% isodecanol +80% n-dodecane. The interaction of 1-decanol with LII and HNO3/Th(IV) with amidic oxygens of LI/LII results in shift of carbonyl stretching frequency, as shown by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) studies. The structural and bonding information of the Th-LI/LII complex were derived from the density functional theoretical (DFT) studies. The molecular dynamics (MD) simulations suggested that the aggregation behavior of the ligand in the present system is governed by the population of hydrogen bonds by phase modifier around the ligand molecules. Although the theoretical studies suggested higher Gibbs free energy of complexation for Th4+ ions with LI than LII, the extraction was found to be higher with the latter, possibly due to the higher lipophilicity and solubility of the Th-LII aggregate in the nonpolar media.

Uranium(VI) and thorium(IV) extraction by malonamides: Impact of ligand molecular topology on selectivity

Uranium(VI) and thorium(IV) extraction from nitrate media with N,N′-dimethyl,N,N′-dibutylteradecylmalonamide (DMDBTDMA) and N,N,N′,N′-tetrahexylmalonamide (THMA) in toluene has been investigated. These two diamides are structural isomers, differing only in the position of alkyl chain substituents. With both ligands, the extraction of uranium(VI) and thorium(IV) is more efficient at higher acidity while uranium(VI)/thorium(IV) selectivity is higher at lower acidity, particularly with DMDBTDMA, for which an almost selective extraction of uranium(VI) has been observed. The selectivity difference between the two ligands has been proven to be mainly due to thorium(IV) extraction, which is strongly dependent on the malonamide molecular structure. On the other hand, uranium(VI) extraction follows the same trend with both DMDBTDMA and THMA. In-depth analysis of molecular and supramolecular features of extracting organic solutions suggests that the disparity of thorium(IV) extraction trends between the two malonamides can be linked to the difference in thorium(IV)-ligand interactions: thorium(IV) extraction appears to lead to rather stable classical coordination complexes with THMA, and more complex supramolecular species with DMDBTDMA. Altogether, these results suggest the prevalence of hydrophobic driven interactions for extraction of metallic cations with DMDBTDMA and electrostatic driven interactions in the case of THMA.

Highly efficient extraction of thorium from aqueous solution by 2-carboxyethylphosphonic acid-functionalized chitosan xerogel

Efficient separation and enrichment of thorium from aqueous solutions is an important subject in the field of energy and ecological environment. In this study, a novel polymer-based xerogel was prepared by a crosslinking reaction of 2-carboxyethyl phosphonic acid functionalized chitosan(CCS-TCEP) and was applied to the adsorption of Th(IV) ions. The maximum adsorption capacity of CCS-TCEP could reach 311.6 mg/g with an excellent selectivity due to the abundant binding sites for thorium provided by TCEP. Moreover, this material has a high adsorption rate and the adsorption equilibrium could be reached within 60 min. After 5 cycles of reuse, the adsorption capacity of CCS-TCEP still retained more than 80 % of its initial value. Furthermore, the extraction mechanism of CCS-TCEP for Th(IV) ions was also analyzed in detail by FT-IR, XPS and DFT calculation. This study indicates that CCS-TCEP can be used as a potential adsorbent for efficient extraction of thorium from aqueous waste.

Separation and recovery of Th(IV) from rare earth and other cation solutions using pH-responsive ionic liquids at high acidity condition of 1 M HNO3

Thorium has received widespread attention as a potential nuclear fuel alternative, but it is still a difficult task to extract thorium from strong HNO3 media. Meanwhile, stimulus-responsive materials have received extensive attention in the field of separation due to their special properties. Herein, we designed and synthesized a new type of stimulus responsive ionic liquid (SIL) material and applied it to solve the problem of low thorium extraction efficiency in strong HNO3 media. By utilizing the pH-response performance of SIL, a SIL and thorium complex (SILTh) is found to self-assemble and precipitate out from solution upon simple adjustment of the pH. We found that the extraction efficiency of thorium can reach 99.6% under high acidity and that it can be even higher than 98.8% when the temperature changes. Under experimental conditions, SIL showed a record-breaking maximum extraction capacity for thorium (644.2 mg g−1) with an excellent selectivity for thorium over lanthanide and transition metal in 1 M HNO3 (S>1400). Studies reveal that PO is complexed with thorium, which also explains the high adsorption capacity and selectivity of SIL for thorium under high acidity. Moreover, the pH-response characteristics of SIL are reversible. The pH-responsive SIL material and the extracted thorium can be recovered, and SIL also shows an excellent recycling ability over five cycles, with extraction and recovery efficiencies for Th(IV) of 98.0% and 98.7%, respectively within five cycles, indicating that the material has a good recycling ability. This study explores the possibility of using pH-responsive materials to recover thorium in strong HNO3 media, and provides ideas for the design and synthesis of new materials for the recovery of thorium.

Supercritical Fluid Extraction of Uranium, Plutonium and Thorium

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.

Supercritical Fluid Extraction of Uranium, Plutonium and Thorium: A Review

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.

The Study of Amidoxime-Functionalized Cellulose Separate Th(IV) from Aqueous Solution.

Selective extraction of low-concentration thorium (Th(IV)) from wastewater is a very important research topic. In this paper, amidoxime cellulose was synthesized, and its composition and structure were characterized by FT-IR, SEM, XPS, and elemental analysis. The adsorption experiment results showed that the adsorption reaction was a spontaneous exothermic process. When the solid–liquid ratio was 0.12 g/L and the pH value was 3.5, the adsorption percentage of the Th(IV) in water onto amidoxime-functionalized cellulose (AO-CELL) could reach over 80%. The maximum adsorption capacity can reach to 450 mg/g. At the same time, the adsorption selectivity, desorption process and reusability of the material were also studied. The results showed that the AO-CELL had a good selectivity for Th(IV) in the system with Sr2+, Cu2+, Mg2+, Zn2+, Pb2+, Ni2+, and Co2+ as co-ions. In the nitric acid concentration of 0.06 mol/L system, the AO-CELL desorption rate of Th(IV) can reach 95%, and the adsorption rate of Th(IV) in aqueous solution of AO-CELL is still above 60% when the AO-CELL is reused four times. The above results show that the amidoxime cellulose adsorption material synthesized by our research group has good selective adsorption performance for Th(IV) of a low concentration in an aqueous solution and has a good practical application value.

Sorption-photometric definition of thorium (IV) in clays

A simple and selective method for sorption-photometric determination of thorium (IV) micro amounts in clay using a new chelating sorbent, a copolymer of maleic anhydride with styrene modified with N1,N1,N2-triphenylguanidine, is proposed. The sorbent is white substance, insoluble in water, acids, weak alkalis and organic solvents. Sorbents were first ground in an agate mortar and sieved through a sieve (0.14 mm). The effect of pH of the medium, the ionic strength of the solution, contact time of the phases, concentration of thorium (IV) in the solution and on the sorption was studied under static conditions. Thorium concentration was determined by the photometric method using 2,2’,3,4-tetrahydroxy-3’-sulfo-5’-chloro-benzene. The concentration of thorium (IV) was calculated using a calibration curve, the results were processed statistically. The full static sorption capacity of the resulting sorbent on K+ ion was 13 mmol/g. An emphasis was also made on the study of the effect of the kinetic properties of sorbents on the sorption process. The maximum degree of thorium extraction by the sorbent was achieved from the solutions with pH 4. The time dependence of sorption was also studied. The results of the study showed that the sorption equilibrium is achieved after 2.5 h of contact of the sorbent with the metal. The sorption of thorium increases with an increase in the thorium concentration in the solution and attains maximum at a concentration of 8 × 10–3 M (pH 4, = 8 × 10–3 M, Vgen = 20 ml, mabsorbed = 0.05 g, sorption capacity = 348 mg/g). The degree of thorium (IV) extraction in optimal conditions exceeds 95%. It is shown that the main micro- and macro-components of clay do not affect the results of the determination of thorium. The developed technique was applied to determine thorium in a clay sample from the Shemakhi region of Azerbaijan. The correctness of the obtained results was confirmed by the spike test.

Effect of Dialkylsulfosuccinate-Based Ionic Liquids on the Extraction of Lanthanides(III), Uranium(VI), and Thorium(IV) with Diphenyl(dibutylcarbamoylmethyl)phosphine Oxide from Nitric Acid Solutions

Effect of Dialkylsulfosuccinate-Based Ionic Liquids on the Extraction of Lanthanides(III), Uranium(VI), and Thorium(IV) with Diphenyl(dibutylcarbamoylmethyl)phosphine Oxide from Nitric Acid Solutions

An integrated strategy for the extraction and solidification of Th(IV) ions from aqueous HNO3 solution based on self-assembly triggered by [DODMA]+[DGA]- ionic liquids

Based on the dioctadecyldimethylammonium chloride surfactant, three novel ionic liquids (ILs) involving dioctadecyldimethylammonium ([DODMA]+ cations and N,N-dialkyl-diglycolamide acid (DGA) anions was firstly designed and synthesized for extraction of thorium ions in nitric acid solution. The integrated extraction and solidification of Th(IV) was developed by formation of self-assembly (SA) solid in two-phase interface. The SA solid was identified by spectroscopic methods including SEM with mapping EDS, XPS, FT-IR and ESI-HRMS. The excellent extraction efficiency was observed for extraction of thorium using [DODMA]+[DGA]- ionic liquids, more than 99% of Th(IV) were extracted and enriched as SA solid in one-step process. The outstanding selectivity of Th(IV) to Ln(III) and U(VI) was observed, and separation factors were up to 3470 for Th/Eu and more than of 1980 for Th/U, respectively. The proposed strategy not only provides an alternate method for the separation of thorium ions with uranyl ions and lanthanides(III) ions in the nuclear fuel cycle, but also pioneers to develop the self-assembly extraction based on [DODMA]+ ionic liquids. In view of the similarity of Pu(IV) and Th(IV), the simple integrated strategy may be further expanded for extraction and enrichment of Pu(IV) in nuclear industry.

Highly Efficient Extraction of Thorium from Aqueous Solution by 2-Carboxyethylphosphonic Acid-Functionalized Chitosan Xerogel

Highly Efficient Extraction of Thorium from Aqueous Solution by 2-Carboxyethylphosphonic Acid-Functionalized Chitosan Xerogel

A Survey on Various Methods of Extraction and Recovery of Thorium

In this survey, some methods of extraction of thorium such as selective extraction of thorium using phosphorodiamidate, selective cloud point extraction of thorium, extraction of thorium from sulfuric acid baking and leaching of monazite, extraction of thorium from chloride solution using Schiff base were discussed. The decomposition of monazite was manifested by sulfuric acid baking and leaching at an elated temperature. The recovery of thorium (Th) from various sources of rare earth and some selective extraction of thorium by using phosphorodiamidate as an extractant was also reported. Using a special synthesized surface-active ionic liquid extractant (SAIL), the cloud point extraction of thorium was analyzed. A synthesized Schiff base was applied for the extraction of thorium in the strategic solvent extraction method. Thorium, using α-amino phosphate extractant from bastnaesite, recovered by using Cyanex 572 and N1923, recovery of Th from industrial residues and recovery of Th from radioactive waste by using IREPO and monazite leached solution were discussed. In this study, the recovery of thorium from the industrial residue as well as from radioactive residue was also discussed.

Применение хелатообразующего сорбента, содержащего фрагменты 4-амино-тиоурацила, для сорбционного извлечения тория(IV) из глины

The article considers the danger of thorium due to its radioactive toxicity. There has been proved the diversity of thorium compounds and the influence of thorium on a human body and the environment. A polymer chelating sorbent containing fragments of 4-amino - thiouracil has been investigated. An isotherm of thorium sorption with the sorbent is constructed and the optimal concentration conditions are determined: pH = 4; = 6 • 10–3 mol/l; Vob = 25 ml; msorb = 0.03 g; sorptive capacity (CE) = 1 163 mg/g. The degree of extraction of thorium(IV) ions under optimal conditions exceeds 95%. The developed technique was applied to extract thorium from clay. Studying sorption was carried out under static conditions using special equipment.

Sequential separation and selective extraction of uranium and thorium from monazite sulfate leach liquor using dipropylamine extractant

Monazite mineral is the main source of uranium and thorium, which are mainly associated with rare earth elements (REEs). So, their separation is the crucial task to satisfy their application for nuclear fuel. Dipropylamine was used for the first time in the selective extraction and separation of uranium and thorium from Monazite sulfate leach liquor. The extraction of thorium (98%) was achieved using dipropylamine in kerosene at pH 1; it was followed by selective extraction of uranium (97%) by Dipropylamine at pH 3. The thermodynamic analysis demonstrated that uranium (VI) and thorium (IV) extraction by dipropylamine is an exothermic process. From the stripped liquor (1 M H2SO4), Th and U were precipitated as oxalate and peroxide, respectively, for technological application. Thus, marketable pure thorium and uranium products were prepared in addition to rare earth concentrate.

Direct synthesis of a chelating carboxamide derivative and its application for thorium extraction from Abu Rusheid ore sample, South Eastern Desert, Egypt

ABSTRACT Direct synthesis of Pyridine-2,6-dicarboxylic a-+cid bis-(3-hydroxy phenyl)]amide, (Pydca), chelating ligand was applied for Th(IV) extraction from Abu Rusheid Ore Sample, South Eastern Desert, Egypt, between latitudes 24° 37ʹ 16ʹʹ N and longitudes 34° 46 ʹ 35 ʹʹ E and far from the Red Sea coast by about 42 km west, using poly phosphoric acid catalyst (PPA). The synthesis of new amide via direct condensation of organic acid and aromatic amine was performed in DMF at 100°C. The immediate condensation reaction led to construct the carboxamide derivative in one easy step dismantling the hard activation, halogenation, step resulting in a good yield production. This cross-coupling reaction appears simple, convenient and has a wide scope of activities. This protocol could be extended to industrial large-scale production processes. Experimental measurements have been optimised such as diluent type, pH, contact time, initial Th(IV) concentration, temperature, pydca conc., co-existing ions and stripping agents. It was found that a maximum value of Th(IV) retention (0.86 × 10−3 mol/L) is observed with 0.015 mol/L pydca/CCl4 chelating ligand at room temperature. From kinetic aspects, it was found that Th(IV) extraction follows the pseudo-first order kinetic model. The thermodynamic parameters, ΔS, ΔH and ΔG were also evaluated indicating an endothermic and spontaneous extraction process with increasing the randomness of the extraction system. Th(IV) can be completely back extracted from the loaded pydca chelating ligand using 0.5 M HNO3, 1 M H2SO4 and 1 M HCl. Finally, the optimised factors have been applied for Th(IV) recovery from Abu Rusheid Ore Sample, South Eastern Desert, Egypt, producing a thorium oxide concentrate with Th(IV) content of 81.43% with a purity of 92.67%.

Ultra-selective ion sieve for thorium recovery from rare earth elements using oxygen-rich microporous carbon adsorption

The ultra-selective extraction of thorium ions (Th(IV)) from lanthanides is of significance to both solve the radioactive pollution issue in rare earth (RE) production and sustainably provide thorium fuel for the liquid fluoride thorium reactors (LFTR). However, it remains a great challenge. Here, we reported an oxygen-rich microporous carbon for ultra-selective extraction of Th(IV) from rare earth elements (REEs) in a wide pH range. This selectivity was derived from the synergy of the oxygen-rich nature, microporous structure of the carbons, the chemical valence, and the ionic size of Th(IV) species. This oxygen-rich microporous carbon presented an ultra-high distribution coefficient (Kd) of 1.15 × 108 mL g−1 for Th(IV) at pH 4.9 in the presence of 15 REEs and revealed outstanding performance for Th(IV) extraction from three simulated RE solutions with high ionic strength of lanthanides. Meanwhile, an exceptional adsorption capacity of 624.98 mg g−1 was obtained in the single Th(IV) solution. Both values were superior to those of reported adsorbents. More importantly, the new adsorbent developed here could be prepared from cigarette butts. These features ensured the oxygen-rich carbon as a promising and cost-effective adsorbent for high-purity thorium extraction from REEs.

DISTRIBUTION OF THORIUM (IV) IONS IN AQUEOUS EXFOLIATING SYSTEM CONTAINING ANTIPYRINE AND SULFOSALICYLIC ACID

The possibilities of an aqueous delaminating system containing antipyrine (AP) and sulfosalicylic acid (SSA) for extracting macro - and microamounts of thorium (IV) were studied. The proposed extraction system eliminates the use of toxic organic solvents. The dependences of the distribution of metal from nitrate solutions between phases on the concentration of reagents, acidity of the medium, the amount of inorganic salting-out agent (NaNO3, NH4NO3, Na2SO4) and the volume of the aqueous phase are determined, and optimal conditions for extraction are found. It is shown that in the organic phase with a volume of 1.6 ml at room temperature, macro-and microamounts of thorium (IV) are extracted by 88 and 90%, respectively. The maximum extraction of the cation is achieved at the ratio of AP: SSA = 2.0 : 1.0 and their concentration, mol/l: 0.6: 0.3, while the acidity of the medium created by nitric acid should be equal to 0.015 mol/l (pHequ. = 1.8-1.9). The extraction of thorium (IV) becomes quantitative if inorganic salts (sodium sulfate, sodium nitrate) are introduced into the AP – SSA – 0,015 mol/l HNO3 – H2O system, which, by reducing the activity of water, increase the concentration of reagents in the aqueous phase. The concentration of salting-out agents should correspond to 1.0 and 2.5 mol/l. A mechanism for the distribution of a mixed thorium (IV) complex containing AP, SSA, nitrate ions, solvated with a salt of antipyrinium sulfosalicylate is proposed. The extract is mixed in any relationship with distilled water, providing the use of various instrumental methods of analysis. A method for extraction-photometric determination of thorium (IV) with a toron indicator has been developed. The limit for the fulfillment of the Bouguer-Lambert-Beer law is established. The apparent coefficient of light absorption is calculated (ε = 1.7∙104).

Nanofiltration Extraction of Uranium and Thorium from Aqueous Solutions

The behavior of uranium and thorium ions in nanofiltration (NF) from aqueous solutions has been studied. It was shown that the retention capacity (R) of the NF membrane for uranium and thorium depends on their state in aqueous solutions. In the case of uranium, the smallest values of R (82–83%) are observed when uranium is in solution as uranyl ions or oxyhydrate complexes at pH in the range from 2 to 6. In solutions with large pH values, the retention of uranium increases (R ≈ 95%) due to the formation of an insoluble U(IV) hydroxide and/or carbonate complexes. In the NF of aqueous solutions of thorium, R grows from 94 to 99% with pH increasing from 1 to 3.5, which is due to the hydrolysis of thorium ions to give oxyhydrate complexes of various compositions. At pH 3–9, the retention of thorium remains constant due to the formation of an insoluble thorium hydroxide. In alkaline solutions (pH > 9), values of R decrease because of the formation of negatively charged hydroxo and/or carbonate complexes. A conclusion is made that the nanofiltration is an effective method for wastewater purification to remove admixtures of uranium and thorium.

The separation of thorium and rare earth elements using [A336][NO3]: insight into a new extraction mechanism

In this study, extraction and separation of thorium(IV) and a few representative rare earths in HNO3 media was evaluated using trioctylmethylammonium nitrate ([A336][NO3]) ionic liquid. An unexpected novel extraction mechanism was identified based on the studies in the slope analysis and ESI–MS spectrum. The trimer of [A336][NO3] was confirmed to dominate the extraction reaction by ESI–MS spectrum before and after the extraction. The extraction efficiency of La(III), Eu(III) and Lu(III) by [A336][NO3] are much lower than Th(IV) in acid medium, which means that it is possible to separate thorium from rare earths or the rare earth ores by using [A336][NO3].