Extraction Of Nd Research Articles

Innovative approach for efficient extraction of Nd from electrorefining waste salt into nuclear waste forms

Electrorefining of the high-burnup spent nuclear fuels is critical to the closed fuel cycle in fast reactors for the sustainable development of nuclear energy. However, a remaining challenge in the electrorefining process is the separation of radioactive rare earth fission products to reduce the geological waste volume. In this work, the extraction of a major radionuclide Nd from the molten waste salt into durable waste forms was investigated through a two-step approach consisting of electrolytic reduction and oxidative extraction. Liquid Bi was found to be effective in the electrolytic extraction of Nd, leading to an extraction efficiency of up to 98.6% and a current efficiency of 93.5%. The Nd target in the resulting Nd–Bi cathode alloy was then selectively extracted using specific oxidizers in a glass melting step. High loadings of Nd2O3 in the converted zinc-in-titania glass ceramic and aluminoborosilicate glass waste forms were achieved, demonstrating the prospect of the proposed method in terms of minimizing radioactive waste generation and recycling of the electrorefining waste salt.

Magnetic resonance imaging: an innovative approach to observe rare metal extraction using ionic liquid.

In the present work, a novel approach has been made to evaluate the extraction mechanism of neodymium (Nd) using trihexyl-tetradecyl-phosphonium benzoate (TTPB) ionic liquid through nuclear magnetic resonance (NMR) techniques. A detailed study on the interactions between the extractant (Nd) and the ionic liquid (IL) is presented. The 1H NMR spectral analysis confirmed that Nd extraction took place through the benzoate anion. Furthermore, the NMR relaxation time of the anion is greatly affected affirming that Nd extraction indeed took place through the benzoate anion. This change in the relaxation time caused by the Nd ion on the protons in the anion and cation in TTPB has been used to visualize the extraction mechanism using 1H MRI. A strong change in the image intensity with respect to the time observed in the IL phase validates the extraction of Nd from the aqueous phase into the IL phase. Also, combining the 1H NMR, diffusion coefficient, Karl-Fischer and ultraviolet-visible absorption spectroscopic (UV-Vis) results, we have elucidated the co-ordination structure around Nd during the extraction process.

Neodymium recovery from NdFeB magnets: a sustainable, instantaneous, and cost-effective method

Sustainable extraction of Nd from e-waste using water dispersible carboxylate functionalized nanocellulose (CFNC).

P350-N235 synergistic extraction system used for the recovery of Nd(III) from waste NdFeB magnets

The recovery of Nd(III) from NdFeB permanent magnets is gaining increasing attention. In the rare earth elements separation industry, wastewater produced through saponification has become a serious environmental problem. In this work, a novel non-saponification P350-N235 synergistic extraction system was established for the extraction of Nd(III) from nitric acid medium. Almost 100% of Nd(III) was extracted by using a P350-N235 system when the molar fraction (X) of P350 was 0.3. And the synergistic enhancement factor Rmax reached 60.03. Firstly, the effects of time, pH, volume ratio and other variables were investigated to determine the extraction behaviors. Response surface methodology (RSM) was used to optimize the extraction conditions. The mechanism of synergistic extraction was investigated by FT-IR, UV–vis, NMR methods and ESP maps, indicating that the composition of the extracted complex was Nd(NO3)3·(P350)2.5(N235)2.5. Then, the extraction thermodynamics and kinetics were also thoroughly investigated, the extraction process is demonstrated to be a spontaneously exothermic reaction. In the NdFeB leaching solution, the synergistic system showed excellent separation factor (β) for Nd/Sm (1.43), Nd/Gd (7.33), and Nd/Dy (9.81). Finally, after 5 cycles, the P350-N235 synergistic system maintained high extraction efficiency. In conclusion, this study overcame the saponification problem in traditional extraction techniques and proposed an environmentally friendly green extraction system.

Bi-functional ionic liquid based on Aliquat 336 and Cyanex 572 for effective separation of Nd(III) and Ni(II) from chloride solution and recover Nd2O3 from waste Nd-Ni-Fe magnets

The recovery of lanthanide elements is considered a vital sector in the field of spent nuclear fuel reprocessing. The current paper describes a novel method for recycling a real scrap NdFeNi magnet from computer hard disks in order to recover Nd(III) as a marketable salt and other valuable by-products while also establishing an environmentally friendly process.Solvent extraction of Nd(III) and Ni(II) ions with the synthesized bi-functional ionic liquid (Bif–IL) based on Aliquat 336 and Cyanex 572 [AL336][Cy572] in kerosene was systematically investigated in a chloride solution. When compared to Cyanex 572 alone, Bif–IL improved not only the extraction percentage of these metal ions but also the separation factors between Nd(III) and Ni(II). The effects of different parameters on the extraction process, as well as thermodynamic parameters, were investigated. Based on the slope analysis method and the IR–spectrum, the extracted species are NdCl3(R4NCy)3(org) and NiCl2(R4NCy)2(org) for the studied metal ions. Following that, the loaded organic phase was successfully stripped for Nd(III) ions with 0.5 mol/L HCl. The McCabe–Thiele diagram was used to determine the number of stages required for the extraction and stripping of Nd(III) ions. Eventually, the separation of Nd(III) from scrap NdFeNi magnet leach liquor demonstrates the efficacy of the suggested process.

Amine/Carboxylic Acid Based Bifunctional Ionic Liquids as Extractants for Nd(III), Sm(III) and Eu(III) from Aqueous Solution Containing EDTA

AbstractTwo bi‐functional ionic liquid extractants (Bif‐ILs) comprising tertiary amine and carboxylic acids, namely [TOAH]+[OHex]− (Tri‐n‐octylaminehexanoate) and [TOAH]+[ODec]− (Tri‐n‐octylaminedecanoate) in kerosene have been used for extraction of Nd(III), Sm(III) and Eu(III) from aqueous phase with EDTA as a complexing agent. The extraction ability of both the extracting agents has been analyzed with respect to variations in shaking time, concentration of extractant, aqueous phase pH, molarity of EDTA, diluents and phase volume ratio. Using 0.08 mol/L EDTA,extraction of Nd(III) was maximum with both the extractants followed by Sm(III) and Eu(III).At 4 : 1 (O/A) phase volume ratio, the extraction percentages using [TOAH]+[OHex]− were 93.42 % (Nd), 89.83 % (Sm), 84.14 % (Eu) and with [TOAH]+[ODec]− the values were 90.42 % (Nd), 89.37 % (Sm), 83.65 % (Eu), respectively.Extraction efficiency of both Bif‐ILs is maximum for Nd(III). Stripping was quantitative with HNO3 and HCl.Speciation studies and FTIR spectra provide valuable information regarding the stoichiometry of the extracted species.

Selective extraction of Nd(III) by novel carboxylic acid based ionic liquids without diluent from waste NdFeB magnets

The development of an environmentally friendly extractant for selective recovery of rare earth elements is critical but still faces significant challenges. Two low viscosity carboxylic acid based ionic liquids [A336][BTA] and [A336][OTA] were synthesized for selective extraction of Nd(III) from waste NdFeB magnets. First, the extraction behaviors of two kinds of ionic liquids were compared under different conditions, such as time, pH value of aqueous phase, dosage of ionic liquids, and concentration of salting-out agent. The optimal extraction condition of [A336][OTA] was optimized by response surface methodology, and the extraction efficiency reached 99.1%. The extraction mechanism was proposed as ion association by UV–Vis spectrum, IR spectrum and 1H NMR, and was supported from that perspective of quantum chemical calculation. The extraction thermodynamics, kinetics and isothermal model were studied in detail. [A336][OTA] maintained an extraction efficiency of 95.6% even after seven cycles. The extractant shows good selective separation performance in waste NdFeB magnets, and is an extractant with good application prospect. This work has provided an environmentally friendly extractant for the recovery of Nd(III) from waste NdFeB magnets.

Separation of lanthanum and neodymium in a hollow fiber supported liquid membrane: CFD modelling and experimental validation

Nickel metal hydride batteries find extensive use in many electronic devices. They contain a small amount of rare earth elements, such as, lanthanum and neodymium, which can be recovered from waste batteries, and reused. Hollow fiber supported liquid membranes (HFSLM) have been used for separation of different metal ions. In this work, a CFD model has been developed for a HFSLM to study the separation of lanthanum ion (La+3) and neodymium ion (Nd+3) from an aqueous solution. The model considers the effect of pH on distribution coefficient DM, which is a function of hydrogen ion (H+) concentration, and has a significant effect on extraction efficiency. The model was validated with the experimental data. An empirical model was fitted with the simulation data, and the parameters were optimized for the effective separation of La+3 and Nd+3. The maximum extraction of Nd+3 was predicted to be 44.97%, whereas extraction of La+3 was estimated to be 3.39%, at the optimized conditions of flow rate: 118.96 ml/min, feed pH: 3.41, and [PC88A]: 41.63 mol/m3, in once-through mode. The proposed CFD model could be helpful in design as well as, scale-up of HFSLM for separation of metal ions, by changing the design and process parameters.

Recovery of rare earths in different media with novel dicarboxylate based ionic liquid and application to recycle SmCo magnets

Recovery and separation of rare earth elements was highly crucial but difficult. In this study, a well-designed new ionic liquid named as benzyltributylammonium decanedioate ([N444Bn]2[SA]) was developed to extract rare earths and separate Sm(III) from the spent SmCo magnets in acetate medium for the first time. To exhibit the superiority of acetate medium, the extraction of Nd(III) and La(III) in three different media were comparatively investigated under different conditions, including equilibrium time, initial pH of aqueous solution, rare earth concentration, extractant concentration, salting-out agent concentration and extraction temperature. The results revealed that the better extractabilities of La(III) were observed in acetate medium rather than those in chloride medium (i.e., 97.6% versus 78.6%), which may be attributed to the low-hydrated nature of acetate ions. Importantly, the back-extraction experiments indicated that 91.4% Nd(III) can be stripped from [N444Bn]2[SA] by using 1.5 mol/L HOAc, revealing the outstanding reusability of ionic liquid in the industrial separation-stripping cycles. Furthermore, the ion association mechanism was proposed to describe the extraction behavior and confirmed by the slope analysis and FT-IR characterizations in three media. In terms of the SmCoCu mixture separation, the maximal separation factor of Sm(III)/Co(II) was calculated as 3078 in simulated solution. Impressively, the recovery of Sm(III) from the actual SmCo magnets by our dicarboxylate-type ionic liquid was also successfully achieved with a recycling rate of 96.8% and a Sm(III)/Co(II) selectivity of 148, which exhibited the potential application in the separation of Sm(III) from the spent SmCo magnets.

Extraction of Ln(III) and An(III) by N,N-di(2-ethylhexyl)- thio-diglycolamic Acid

ABSTRACT The extraction of Nd(III), Eu(III), Am(III), and Cm(III), trivalent lanthanides and actinides in high level nuclear waste, by the extractant N,N-di(2-ethylhexyl)-thio-diglycolamic acid (HDEHSDGA, HA) is investigated via thermochemical and spectroscopic methods. In this study, HDEHSDGA behaves as a conventional mono-basic cation-exchanging ligand extracting Ln(III) and An(III) from nitrate solutions of pH region. The information obtained from the extraction experiments and the spectroscopic analyses indicate that the primary extracted complex species may be MA3 · 2H2O for these four cations and likely for the other trivalent f-elements. In the extracted complexes, the anionic monomer extractant A− coordinates to the metal ions presumably forming bidentate coordination via the carbonyl oxygen atom and one of the oxygen atoms of the carboxylate; it appears that the thio-ether does not directly participate in the complexation reaction. The results ultimately demonstrate that HDEHSDGA does not exhibit significant selectivity for An(III) over Ln(III), in contrast to results reported in a previous study conducted with unpurified extractant.

Electrochemical extraction kinetics of Nd on reactive electrodes

• Pyroprocessing technology is a promising technology for the reprocessing of spent fuel. • It is critical to pursue electrode materials with high An / Ln separation efficiency. • The electrochemical reduction of Nd 3+ on the W electrode is a two-step reduction process. • The kinetic properties of Nd 3+ on W, reactive electrodes were measured. • Cd was evaluated as a favorable electrode material for electrochemical extract ion of Nd. Pyroprocessing technology with molten salt electrolysis as the core is a promising technology for the reprocessing of spent fuel. In this work, the electrochemical reduction mechanism and kinetic properties of Nd 3+ on various electrodes (inert W and reactive Al, Ga, Bi, Cd, Zn, Pb, and Sn electrodes) were systematically investigated and compared in LiCl-KCl eutectic melts using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel techniques. The electrochemical reduction of Nd 3+ was a two-step process on the W electrode including Nd 3+ →Nd 2+ and Nd 2+ →Nd, while it became a one-step process involving three electrons on the reactive electrodes with obvious depolarization effects. Furthermore, the connections between the reduction potentials of Nd 3+ on these reactive cathodes and the formation energies of the electrode-rich alloy phases (Al 11 Nd 3 , Cd 11 Nd, Pb 3 Nd, Zn 17 Nd 2 , Ga 6 Nd, Sn 3 Nd, BiNd 2 ) were established. After evaluating the physicochemical, depolarization and kinetic properties of these reactive electrodes, liquid Cd was considered as the most favorable material for the electrochemical extraction of Nd. In addition, Al, Cd, and Bi are also promising candidates for An / Ln separation.

Synergistic solvent extraction of neodymium form nitric acid medium using Cyanex 302 and D2EHPA

AbstractIn this research, a binary mixture of Cyanex 302 (bis‐2,4,4 trimethylpentyl monothiophosphinic acid) and D2EHPA (di‐2‐ethylhexyl phosphoric acid) in kerosene was used for extracting neodymium from nitric acid medium. The different variables affecting the extraction of Nd(III) such as contact time, solution acidity, extractant concentration, and temperature were investigated. Stripping of neodymium ions from the loaded organic phase using HCl, HNO3, and H2SO4 for the re‐extraction of neodymium was also carried out. Results indicated that the most efficient reagent for the stripping of neodymium was nitric acid. The extraction reaction of neodymium with the synergistic mixture was determined using graphical method to be NdH5A2B6. The organo‐metallic complex containing neodymium was examined by Fourier Transform Infrared Spectroscopy (FT‐IR). The values of stoichiometric coefficients and thermodynamic parameters were calculated for this mixture. The extraction was an endothermic process, and the thermodynamic functions, ΔH and ΔS were determined to be 10.532 kJ/mol and −123.681 j/mol °K, respectively for the system under study. The Cyanex 302+D2EHPA system not only increased the extraction efficiency of neodymium but also improved the selectivity significantly. The separation factor of neodymium and praseodymium suggested that this mixture would be of practical value in the separation of neodymium.

Liquid-liquid extraction of Nd+3 and Eu+3 from aqueous medium using oxytetracycline in dichloromethane

Abstract Liquid-liquid extraction system consisting of oxytetracycline (HOTC) in dichloromethane was developed for extraction of Nd+3 and Eu+3 from acidic solutions using radiometric technique. Various extraction parameters such as pH, equilibration time and metals concentration were optimized. Slope analysis method was used to study the composition of product and was found to be M(OTC)3 [here M=Nd+3 or Eu+3 and OTC = conjugate base of HOTC]. Among cations Al+3 and Fe+3 while among anions F− effected the extraction of these metals. Higher separation factor of these metals was found with many others. The method was successfully applied on spiked sea water.

Chemistry of Solvent Extraction of Nd(NO3)3 and Pr(NO3)3 from Nitrate Solutions with TOMAN–TBP Mixtures in Toluene

Chemistry of Solvent Extraction of Nd(NO3)3 and Pr(NO3)3 from Nitrate Solutions with TOMAN–TBP Mixtures in Toluene

Selective and efficient extraction of Nd from NdFeB magnets via ionization in LiCl-KCl-CdCl2 melt

The growing popularity of NdFeB magnets has created a demand for sustainable Nd recycling processes with fewer byproducts and higher extraction efficiencies. To address this need, we herein studied the extraction of Nd from NdFeB magnets via selective ionization in CdCl2-LiCl-KCl at 773 K. When the CdCl2 content was sufficiently large to completely ionize Nd into Nd3+,> 99% of Nd was selectively extracted into the salts within 2 h, while Fe and B remained in the solid phase. The microstructural and compositional changes of the magnet and salts were examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and by inductively coupled plasma-optical emission spectrometry. In the presence of CdCl2, the magnet was naturally fragmented and pulverized. Correlations between CdCl2 content and cyclic voltammetry data (peak current density and peak potential) were established and validated to monitor the reaction progress on-line, and the maximum correlation errors for peak current density and peak potential were found to be less than 8.33% and 16.1%, respectively. Finally, the results of this study were combined with those of previous works to propose a novel Nd recycling process based on molten salt usage.

Nonstationary separation of Nd and Pr by P507 extractant

The low efficiency of the separation of rare earth metals by extraction on one stage requires the combination of a large number of mixer-settlers in a cascade. The problem of increasing the rare earth elements separation factor is extremely urgent. One of the perspective methods is the nonequilibrium nonstationary process. In this work, it is offered to use the principle of a nonstationary extraction in the separation process of the Nd/Pr pair from chloride medium by the extractant based onP507. The results which have been received by an experimental setup allowing the monitoring of the influence of a cyclic change of physical-chemical parameters on extraction in the online modeare discussed. A comparison of two ways of implementation of extraction in the nonstationary mode is carried out. The apparent values of physical-chemical parameters (ΔG, ΔH, ΔS) in the temperatures range 15-65 °C are calculated from the data of joint extraction of Nd and Pr.

Enabling Microscale Processing: Combined Raman and Absorbance Spectroscopy for Microfluidic On-Line Monitoring.

Microfluidics have many potential applications including characterization of chemical processes on a reduced scale, spanning the study of reaction kinetics using on-chip liquid-liquid extractions, sample pretreatment to simplify off-chip analysis, and for portable spectroscopic analyses. The use of in situ characterization of process streams from laboratory-scale and microscale experiments on the same chemical system can provide comprehensive understanding and in-depth analysis of any similarities or differences between process conditions at different scales. A well-characterized extraction of Nd(NO3)3 from an aqueous phase of varying NO3- (aq) concentration with tributyl phosphate (TBP) in dodecane was the focus of this microscale study and was compared to an earlier laboratory-scale study utilizing counter current extraction equipment. Here, we verify that this same extraction process can be followed on the microscale using spectroscopic methods adapted for microfluidic measurement. Concentration of Nd (based on UV-vis) and nitrate (based on Raman) was chemometrically measured during the flow experiment, and resulting data were used to determine the distribution ratio for Nd. Extraction distributions measured on the microscale were compared favorably with those determined on the laboratory scale in the earlier study. Both micro-Raman and micro-UV-vis spectroscopy can be used to determine fundamental parameters with significantly reduced sample size as compared to traditional laboratory-scale approaches. This leads naturally to time, cost, and waste reductions.

Structural effects of neutral organophosphorus extractants on solvent extraction of rare-earth elements from aqueous and non-aqueous nitrate solutions

A series of neutral organophosphorus extractants, comprising phosphine oxides, phosphinates, phosphonates and phosphates with linear and branched alkyl chains have been synthesized. Together with some similar commercial extractants, the performance of these new compounds in the extraction of Nd(III) and Dy(III) from both aqueous nitrate and non-aqueous ethylene glycol nitrate solutions was investigated. It was observed that: (1) the order of extraction efficiency of the rare-earth elements is the same as the basicity (electronegativity) of the extractant molecules: phosphine oxide > phosphinate > phosphonate > phosphate; (2) the same type of extractants with longer alkyl chains show higher metal extraction efficiencies, and branched chains hamper the extraction; (3) extraction from ethylene glycol solutions give higher separation factors for all types of neutral organophosphorus extractants than the corresponding aqueous solutions; and finally (4) phosphinates and phosphonates are more promising extractants than phosphine oxides and phosphates for separation of Nd(III) and Dy(III) by solvent extraction from ethylene glycol solutions. These results are useful for the development of more efficient and more selective new extractants and separation processes.

Antagonism in the aggregation behaviour of N,N,N′,N′-tetraoctyldiglycolamide in n-dodecane upon adding N,N-dioctylhydroxyacetamide during trivalent metal extraction

The solvent phase composed of tetraoctyl diglycolamide (TODGA) in n-dodecane (n-DD) undergoes the undesirable organic phase splitting during the solvent extraction of trivalent actinides and lanthanides from nitric acid medium. To overcome this limitation a neutral extractant namely the N,N-dioctyl hydroxyacetamide (DOHyA), which was half the molecule of TODGA, has been added to the solvent phase and evaluated for the extraction of Nd(III) from nitric acid medium. Since the reverse micellar aggregates of the extracted species in the organic phase was responsible for organic phase splitting, the aggregation behaviour of the organic phase was probed by dynamic light scattering (DLS) technique. The results have been compared with the individual solvent systems, namely DOHyA/n-DD and TODGA/n-DD. The investigations revealed that the extraction of nitric acid and loading of Nd(III) in organic phase increased upon adding DOHyA, but the size of aggregates formed in the organic phase decreased remarkably with DOHyA addition, which was in contrast to the expected behaviour of increase in aggregate size with increase of extraction in the organic phase. To understand the unexpected behaviour of aggregation, the extracted organic phase was further probed by UV–visible and luminescence spectroscopy. The results further revealed that DOHyA in the binary solution served as a reactive organic phase modifier and induced antagonistic effect on aggregation when mixed with TODGA, which was, in fact an advantage for the extraction of trivalent actinides from high-level nuclear waste.

Selection criteria of diluents of tri-n-butyl phosphate for recovering neodymium(III) from nitrate solutions

The selection of a proper diluent should be based on several criteria such as the distribution ratio, phase disengagement time, cost, safety and environmental impact of the process. The effect of different diluents on the solvent extraction of Nd(III) by the neutral extractant tri-n-butylphosphate (TBP) from nitrate feed solutions was studied. The nature of the diluent had little effect on the extraction kinetics of Nd(III) by TBP above 2.5min. In general, phase disengagement times were relatively shorter for aromatic diluents compared to aliphatic diluents. Conversely, extraction efficiencies were the highest for aliphatic diluents, slightly lower for mixed aliphatic-aromatic diluents and much lower for aromatic diluents. The poorer extraction efficiencies of aromatic diluents maybe due to the lower concentration of free extractant as a result of the stronger interactions of the diluent with water and/or of the diluent with the extractant. Under the experimental conditions, the differences in extraction between aliphatic and aromatic diluents decreased with increasing the salting-out effect of nitrate ions in the feed. At nitrate concentrations of 4.5molL−1 or more, the different diluents had a limited influence on the metal extraction with 1molL−1 TBP from feed solutions of 1gL−1 Nd(III). Thus, under these conditions, the selection of the diluent can be preferably based on its cost, safety and biodegradability rather than on its physico-chemical properties.