Extraction Of Cerium Research Articles

Characteristics and Performance of Cerium Extraction from Cerium Hydroxide Concentrate using Tri Butyl Phosphate

Characteristics and Performance of Cerium Extraction from Cerium Hydroxide Concentrate using Tri Butyl Phosphate

Rapid and efficient extraction of cerium by forming Al-Ce alloys in LiCl-KCl molten salts

The extraction of lanthanides in spent fuel reprocessing plays a key role in the development of nuclear energy. In this work, the extraction of the typical fissionable cerium elements has been studied by electrolytic co-reduction of Al(III) and Ce(III) in LiCl-KCl-CeCl3 molten salts assisted by KAlCl4. The electrochemical behavior of the reduction of Al(III) and Ce(III) on a molybdenum electrode was studied by cyclic voltammetry (CV), square wave voltammetry (SWV), and open circuit chronopotentiometry (OCP), and specific peaks of five Al-Ce intermetallic compounds were detected. After 2.7 h of galvanostatic electrolysis at a current density of 0.064 A cm-2, the extraction efficiency and current efficiency of Ce(III) reached 99.9 % and 91.3 % respectively. Potentiostatic electrolysis is slightly more efficient, with 99.9 % Ce(III) extraction in 3.5 h at a current efficiency of 97.8 %. The products of electrolysis are rod-shaped alloys (Al11Ce3, Al3Ce, Al2Ce), and the molten salts purified by electrolytic separation are free of impurity signals and can be reused for electrolytic refining.

Extraction of Cerium from Nitric Acid Medium using Cyanex 302 and Cyanex 572

In this paper, the extraction of cerium from the synthetic environment ([Ce]=0.04 M) was investigated using the solvent extraction method with a mixture of solvents. Considering that the synergy of extractants can lead to the improvement of cerium extraction, Cyanex 302 solvent was used for synergy with Cyanex 572. The results showed that the combination of Cyanex 572-Cyanex 302 can extract a high percentage of cerium (> 90%). Also, the value of ΔG is equal to 18.61 (kJ/mol), so the extraction reaction of Ce (III) is non-spontaneous.

Extraction kinetics of lanthanum and cerium in bis(2-ethylhexyl) phosphate (HDEHP)–lactic acid complex system using Lewis cell

The kinetics of the bis(2-ethylhexyl) phosphate (HDEHP) extraction of lanthanum and cerium were investigated in a lactic acid complex system. The effects of stirring speed, specific interface area, temperature and concentration of different solution components on the extraction rate were studied using a constant interface cell device. When the stirring speed was 130–180 r/min, the extraction reaction rate was mainly controlled by the chemical reaction, and increased with increasing the specific interface and temperature. The extraction kinetics shows that the extraction reaction conforms to a pseudo-first-order reaction, and the mass transfer process occurs at the interface between the organic and liquid phases rather than in the bulk phase. The Gibbs free energy of the extraction reaction ΔG<0, indicating that the reaction can proceed spontaneously, while the calculation of the apparent activation energy shows that HDEHP is more likely to combine with cerium during extraction.

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

Synthesis of new extractant P113 for cerium(IV) extraction and higher separation over thorium from bastnaesite

Cyanex923 (a mixture of four trialkyl (hexyl and octyl) phosphine oxides) has been extensively employed in the recovery of cerium (Ce(IV)) and fluorine (F), as well as the separation over thorium (Th(IV)) from bastnaesite. However, rigorous production conditions and involvement of highly toxic raw materials (PH3) have been critical problems to be solved during the synthesis of Cyanex923. Meanwhile, its extraction performance remains to be improved. Therefore, we attempted to adjust the feed ratio to increase the proportion of short carbon chain components, successfully synthesized a novel extractant (P113, a mixture of four trialkyl (hexyl and octyl) phosphine oxides) with contents of each component different from Cyanex923 using an environmentally benign method. The comparison with Cyanex923 revealed obvious improvement of P113 in terms of extraction efficiency, selectivity and saturation capacity. The extraction efficiency and saturation capacity of Ce(IV) were increased by 10% and 10 g L-1, respectively. Separation factor of Ce(IV)/Th(IV) was increased from 16 to 27 at 2 mol L-1 H2SO4. Furthermore, P113 presented excellent regenerability. The superiority of P113 was theoretically explored using the density functional theory (DFT) and polarizable continuum model (PCM), and the results indicated that THPO (trihexyl phosphine oxide) had lower extraction phase transfer energy than TOPO (trioctyl phosphine oxide) from aqueous phase to organic phase. The comprehensive evaluation of P113 demonstrated the feasibility employed in the recovery of Ce(IV)-F and the separation of Th(IV) from bastnaesite, which advanced industrial application of the novel extractant, and held significant value for the utilization of resources and environmental protection.

Recovery of light rare earth elements, cerium, lanthanum, and neodymium from alluvial gold mining waste from the Bagre-Nechí mining district in Colombia using acid leaching, oxalate precipitation and calcination

This paper investigates different leaching conditions with hydrochloric acid and sulfuric acid, which perform the maximum extraction of cerium, lanthanum, and neodymium from a dephosphorized monazite concentrate obtained from alluvial gold mining waste from the Bagre-Nechí mining district in Colombia, for the subsequent recovery of oxides of these metals. Sulfuric acid as the leaching medium at all evaluated concentration, time, and temperature conditions gave highest extractions. The addition of 10% (v/v) H2O2 increased rare earth dissolution up to 93% in H2SO4 medium. Thermodynamic analysis indicates that H2SO4 solutions show a higher capacity to solubilize REEs as opposed to HCl solutions, thus supporting the experimental results. Rare earths in sulfuric acid liquor can be recovered up to ∼100% by precipitation with a 1.0 M oxalic acid solution at 25 °C for 120 min, followed by the calcination of the oxalate precipitate at 850 °C for 120 min. The final product was characterized by XRD, which indicated a composition of CeO2, La2O3, and Nd2O3. The results of the XRD analysis show the REE phase transformation throughout the process.

Supercritical Fluid Extraction of Cerium from Aqueous Solutions Using Tributyl Phosphate as a Ligand

Supercritical Fluid Extraction of Cerium from Aqueous Solutions Using Tributyl Phosphate as a Ligand

A Product Diffusion Model for the Extraction of Cerium and Yttrium from Magnetic Coal Fly Ash Using Citric Acid Solution

The recovery of rare earth elements from coal-related materials, primarily fly ash, has become an emerging topic for the past few years. The availability of fly ash as solid waste from coal combustion and its low radionuclide concentration

Recovery of Rare Earth Elements from Mining Tailings: A Case Study for Generating Wealth from Waste

The growing demand for rare earth elements (REE) driven by their applications in modern technologies has caused the need to search for alternative sources of these elements as their extraction from traditional deposits is limited. A potential source of light rare earth elements (LREE) may be the monazite present in the mining waste generated in the Bagre-Nechí mining district in Colombia due to the processing of sands containing alluvial gold. Consequently, in this research, a systematic evaluation has been carried out for the extraction of Ce, La, and Nd from a leach liquor obtained from monazite present in alluvial gold mining tailings. The leaching process carried out with HCl indicated the recovery of approximately 90% of La and Nd and ∼60% of Ce; the solvent extraction tests of these elements showed that increasing the contact time and pH of the leaching liquor positively affects the extraction of lanthanum, cerium, and neodymium, achieving extractions close to 100% with D2EHPA and to a lesser extent with Cyanex572. McCabe–Thiele diagrams for extraction with D2EHPA indicated the requirement of three stages for the extraction of Ce, La and Nd.

Predictive capability evaluation and mechanism of Ce (III) extraction using solvent extraction with Cyanex 572

Owing to the high toxicity of cerium toward living organisms, it is necessary to remove cerium from aqueous solutions. In this regard, the extraction of cerium (Ce (III)) from nitrate media by Cyanex 572 under different operating conditions was examined in this study. The effect of contact time, pH, extractant concentration, and nitrate ion concentration were investigated to characterize the extraction behavior of cerium and based on these outcomes, an extraction mechanism was suggested. The analysis of infrared spectra of Cyanex 572 before and after the extraction of cerium indicated that cerium extraction was performed via a cation-exchange mechanism. Then, the predictive models based on intelligent techniques [artificial neural network (ANN) and hybrid neural-genetic algorithm (GA-ANN)] were developed to predict the cerium extraction efficiency. The GA-ANN model provided better predictions that resulted higher R2 and lower MSE compared to ANN model for predicting the extraction efficiency of cerium by Cyanex 572. The interactive effects of each process variable on cerium extraction were also investigated systematically. pH was the most influential parameter on cerium extraction, followed by extractant concentration, nitrate ion concentration and contact time. Finally, the separation of cerium from other rare earth elements like La (III), Nd (III), Pr (III), and Y (III) was conducted and observed that the present system provides a better separation of cerium from rare heavy earth than light rare earths.

Extraction and separation feasibility of cerium (III) and lanthanum (III) from aqueous solution using modified graphite adsorbent

Graphite (GR) and graphite/alginate (GRA) composite were synthesized utilizing the thermal annealing technique and used as a new adsorbent material for the selective separation and removal of La(III) and Ce(III) from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy, thermal analysis (DTA, TGA), X-ray diffraction (XRD), surface area, porosity, and scanning electron microscope (SEM) were also used to characterize the generated material. Distinct experiments were performed to test the ability of the GRA to La(III) and Ce(III) removal, which include the effect of pH, shaken time, initial concentration of La(III), and Ce(III) at different temperatures range. After 20 min, both ions have reached equilibrium. The pseudo second-order kinetic model was chosen as one which best fits the experimental evidence and better reflects the chemical sorption process. Adsorption isotherm was studied using the Langmuir, Freundlich, and D-R models. The Langmuir model was used to better fit the results obtained. At 25 °C, Ce(III) and La(III) have maximum monolayer capacities of 200 and 83.3 mg/g, respectively. The sorption was endothermic reaction and spontaneous, as illustrated by the data of thermodynamics studies. GRA has the ability to be used as a novel lanthanide adsorbent material, especially for selective separation between Ce(III) and La(III).

Study on the Extraction of Cerium(IV) from Nitric Acid Medium with tri-Isoamyl Phosphate

This paper studied the extraction behavior of tri-isoamyl phosphate (TiAP)/n-dodecane as extractant for Ce(IV) in a nitric acid medium. In the study of extraction of pure Ce(IV) solution, the test results show that when the organic phase and the water phase ratio is 1: 1, the organic phase and the water phase are mixed and contacted for 90 s, and the pH value is 0-2.0, the extraction tends to be balanced, and the complexes formed by the extraction are theoretically deduced and obtained the theoretical molecular formula of the complex is Ce(NO3)4·nTiAP, where n is between 2 and 3; under this condition, the extraction rate of pure Ce(IV) can reach 99.45% after 16-stage countercurrent extraction test; the relative standard deviation is less than 2%. In the extraction of Ce(IV) solution containing other metal ions, the test results show that the extraction rate of 0.05 mol·L-1 TiAP/n-dodecane solution to the material liquid containing Ce(IV) 0.005 g·L-1 is about 64%. However, the experiment found that the extraction rate tends to decrease with the increase of the material liquid’s standing time. After 24 hours, the extraction rate is close to 0. Then, the experiment researched the influence of each metal ion component on the extraction after standing and obtained the metal. In the presence of ionic components, the extraction rate tends to decrease with the increase of the liquid standing time. Considering the strong oxidizing property of Ce4+ under acidic conditions, the experimental study of TiAP on Ce3+ and Ce4+ mixtures with different percentages. The results show that as the percentage of Ce3+ in the feed liquid increases, the extraction rate is in a downward trend, and the trend is consistent with the increase in the standing time on the extraction rate. The original liquid contains impurity Ce4+ is slowly reduced to Ce3+, which affects the extraction results. Studies have shown that TiAP of 0.05 mol·L-1 performs well for the extraction of Ce4+ in pure Ce(IV) solution; TiAP of 0.05 mol·L-1 is effective for extraction of Ce(III) solution of 0 ~ 5 mg·L-1. The effect of Ce3+ is not obvious; because Ce4+ is too oxidizing, when other metal ions studied are present at the concentration studied, it will accelerate the reduction of Ce4+ and affect the extraction results.

Removal of cerium ions in pilot scale agitated column with sieve structure, case study: Evaluation of mass transfer models

The development of the process and scale-up of the agitated column was carried out by the knowledge and prediction of mass transfer rates. This study aimed to apply and validate the mass transfer models for measuring the mass transfer rate. Experimental studies were performed in a pilot-scale agitated column with sieve structure, with cerium extraction from the aqueous phase to the organic phase. The extraction rate with concentration profile was measured and used as an input to mass balance expressions to calculate the mass transfer coefficients. The results showed that the axial dispersion and backflow parameters also change significantly under operating conditions. The most influential parameter was agitation speed; increasing it from 170 to 410 rpm, the extraction efficiency, backflow parameters and axial dispersion parameters were shifted from 50%, 0.5 and 0.5–90%, 3 and 6, respectively. The evaluation of mass transfer models indicates that cerium removal improves when the forward mixing model with drop size distribution (X-AARE, Y-AARE equals 7.68, and 8.66) is used instead of PFM, BFM, and ADM models. This work illustrates the possibility of predicting the mass transfer performance of a pilot-scale agitated column using a validated FMM model for extraction of rare-earth ions.

Optimization of cerium extraction from aqueous solutions by response surface methodology employing 4‐factor Box‐Behnken design

AbstractIn this research, the solvent extraction of Cerium (III) using Cyanex 572 has been investigated under variations of the pH, extractant concentration, nitrate ion concentration, and contact time. Box‐Behnken design and analysis of variance were applied to determine the main effects and their interactions. The high R2 value obtained from the developed model indicated a good correlation between the predicted and measured data. Contact time had no significant effect on the extraction of cerium. pH and extractant concentration were the most significant parameters affecting the cerium extraction under the examined conditions. The developed model was applied to find out the optimum values of the selected variables for the maximum extraction of cerium. The nature of diluent influences the extraction efficiency of Cerium (III). Kerosene was found to be efficient diluent for the extraction of cerium in terms of better extraction capability as investigated.

Preparation and application of Fe3O4@Acetamidoxanthate as a unique nanosorbent in heavy metal removing

Chelating agents are one of the most important substances in metal extraction, but separation is the main problem in the use of these agents as an adsorbent. After the adsorption of metals by an external magnet, magnetic NPs provide the possibility of easy collecting and isolating the adsorbent nanomaterial for many applications. Given the immense importance of magnetic NPs, there has been widespread interest in accessing the above adsorbent. In the present study, an attempt was made to synthesize acetamido xanthate which was coupled to NPs and has the potential to be used as a nano-adsorbent for the removal of heavy metals. This novel nano sorbent was characterized by scanning electron microscopy (SEM), Fourier transforms infrared (FT-IR), and Nuclear Magnetic Resonance (NMR) spectroscopy. The effect of some parameters such as temperature, time, pH, and the amount of adsorbent on the extraction reaction was investigated. The optimized condition for extraction of cerium was temperature of 30°C, pH = 8, reaction time of 45 minutes using 7.5 mg of the prepared nanosorbent, that in such condition the yield of reaction achieved up to 97%. The prepared adsorbent showed high efficiency in the adsorption of heavy metals specifically.

Study of cerium and neodymium leaching from Kazakhstan phosphogypsum

The processes of extraction of cerium and neodymium from Kazakhstan phosphogypsum, a large-tonnage waste of mineral fertilizer production of "Kazphosphate" LLP, have been studied. The influence of the nature of the leaching agent, temperature and duration of the process on the efficiency of cerium, neodymium leaching using the methods of X-ray fluorescence, X-ray phase and energy dispersive elemental analysis was studied. It has been found that the use of hydrogen peroxide as an oxidizer in the leaching of rare earth metals intensifies the process of recovery from phosphogypsum by 20% for cerium and by 28% for neodymium. Optimal parameters of cerium and neodymium leaching under atmospheric and autoclave conditions have been found. In atmospheric conditions, recovery of cerium and neodymium were 70.3% and 92.0%, in autoclave conditions 72.9% and 87.5%, respectively. The obtained results allow us to hope for the processing possibility of these wastes with the aim of rare-earth metals and other valuable products recovery.

Assessment of mass transfer coefficients in extraction stages of La(III) and Ce(III) ions by using rotating Scheibel column with regular packing structure

The extraction of rare earth metals is critical due to their applicability in the industry. Because of this subject’s importance, the Scheibel column with the regular packing structure was investigated in the extraction process of lanthanum and cerium ions. Mass transfer coefficients identified the column performance in the transport stage of La(III) and Ce(III) from the aqueous phase to the organic phase. The variations in operating conditions were investigated to optimize the extraction of two ions. The backflow model (BFM), axial dispersion model (ADM), and forward mixing model (FMM) were investigated to evaluate the mass transfer performance in the column. The result showed that the description of the volumetric overall mass transfer coefficient with the forward mixing model is more significant than the two other models. The FMM model was evaluated by the function of droplet size and droplet residence time and the concentration profiles fitting technique. The medium of average absolute relative error obtained by the FMM model is ~ 4.45% and ~ 18.40% (lanthanum extraction) and ~ 10.75% and ~ 14.99% (cerium extraction) for the continuous and dispersed phase, respectively. It indicated that the applied model has a remarkable accuracy for the description of mass transfer performance. The result showed that the rotor’s speed has the most notable effects on the extraction conditions.

Selective Leaching of Rare Earth Elements from Ion-Adsorption Rare Earth Tailings: A Synergy between CeO2 Reduction and Fe/Mn Stabilization.

The increasing demand for rare earth elements (REEs) motivates the development of novel strategies for cost-effective REE recovery from secondary sources, especially rare earth tailings. The biggest challenges in recovering REEs from ion-adsorption rare earth tailings are incomplete extraction of cerium (Ce) and the coleaching of iron (Fe) and manganese (Mn). Here, a synergistic process between reduction and stabilization was proposed by innovatively using elemental sulfur (S) as reductant for converting insoluble CeO2 into soluble Ce2(SO4)3 and transforming Fe and Mn oxides into inert FeFe2O4 and MnFe2O4 spinel minerals. After the calcination at 400 °C, 97.0% of Ce can be dissolved using a diluted sulfuric acid, along with only 3.67% of Fe and 23.3% of Mn leached out. Thermodynamic analysis reveals that CeO2 was indirectly reduced by the intermediates MnSO4 and FeS in the system. Density functional theory calculations indicated that Fe(II) and Mn(II) shared similar outer electron arrangements and coordination environments, favoring Mn(II) over Ce(III) as a replacement for Fe(II) in the FeO6 octahedral structure of FeFe2O4. Further investigation on the leaching process suggested that 0.5 mol L-1 H2SO4 is sufficient for the recovery of REEs (97.0%). This research provides a promising strategy to selectively recover REEs from mining tailings or secondary sources via controlling the mineral phase transformation.

Influence of cerium salt concentration, co-solvents and water on the efficiency of supercritical CO2 extraction

The extraction of cerium from cotton substrate, as a matrix model, using supercritical CO2 modified with phosphorus extractant and co-solvent/water in wise proportions, has been investigated. Using a recently developed isobutyl amidophosphonate extractant, the aim of this study was to emphasize how besides the usually considered operating parameters (flow rate, pressure and temperature), the efficiency of supercritical CO2 extraction of cerium depends on the concentration of cerium nitrate deposits on the substrate (between 0.27 and 261 mg gcotton−1) and on the presence and composition of co-solvent/water mixture as well. The variations of the extraction efficiency with the nature of the Ce nitrate deposits (aggregates or homogenous layers) are explained by using a deposition model confirmed using SEM and coupled with SAXS data. Extraction is promoted when Ce nitrates deposits are in the form of segregated aggregates instead of homogeneous layers. Phase equilibrium data for CO2-ethanol-amidophosphonate and CO2-isopropanol-amidophosphonate ternary systems have been measured at 40 °C and 25 MPa to investigate the benefit of using a co-solvent. Extraction experiments show that adding a co-solvent and carefully adjusting the water concentration up to 30%wt are crucial to obtain high mass extraction yields, here up to 82%.