Synergistic extraction of yttrium using mixtures of organophosphorus extractants (original) (raw)
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Analytica Chimica Acta, 2005
Synergistic extraction and separation of yttrium (Y) from heavy rare earths (HRE) in chloride medium using mixture of sec-octylphenoxy acetic acid (CA-12, HA) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272, HL) in n-heptane has been investigated. The synergistic enhancement coefficients, R max , were obtained for Ho 3+ (5.12), Y 3+ (5.34), Er 3+ (7.04), Tm 3+ (7.50), Yb 3+ (13.12) and Lu 3+ (17.58). The separation factors (SF) between Y 3+ and HRE were obtained, and it was found that Er 3+ would form the new complex as ErH 6 A 4 L 5 in the mixture system. A cation exchange mechanism was proposed. The equilibrium constant, formation constant and thermodynamic parameters such as G = −18.48 kJ/mol, H = −1.36 kJ/mol and S = 0.058 kJ/mol were determined. The CA-12 and Cyanex272 mixture system showed higher extraction efficiency, larger separation factors as well as excellent stripping behaviors. The application potential of the mixture system to separate Y from HRE has been discussed.
Analytica Chimica Acta, 1996
The distribution of yttrium(III) between acidic aqueous chloride solutions and organic solutions of di(2-ethylhexyl) phosphoric acid, D2EHPA, in kerosene has been examined as a function of various chemical parameters at constant aqueous ionic strength 2.0 M and different ranges of metal concentration. For low and middle metal concentration, 1.5 × 10−4 − 2.587 × 10−2 M (13–2300mg l−1), the distribution of yttrium has been examined as a function of the extractant concentration and at fixed [H+] of 1.0M. The distribution data has been analyzed by both graphical and numerical methods. The results for the low metal concentration may be explained by the formation of two organic metal species, YA3.2HA and YA3.HA (HA refers to D2EHPA). Equilibrium constants have been determined and they are compared with corresponding constants in nitrate media and with results reported in the literature. Possible mixed extracted complexes containing chloride were rejected by the numerical calculations. Such prediction was confirmed by separate analysis of the chloride content in the organic phase. When the metal concentration is increased, the system shows a major complexity which is attributed to the formation of aggregates in the organic phase. For the highest metal concentration, a gel is observed to form under some of the experimental conditions. These results are discussed in terms of polymeric metal complexes.
ACS Sustainable Chemistry & Engineering, 2018
Experiments were carried out in slug flow microreactor to systematically investigate reaction behavior under variation of flow rate, and made comparative study. Y-junction microreactor and T-junction microreactor have been used to extract yttrium (III) using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (EHEHPA or P507). Results show that the maximum extraction efficiency of 90.4% in both microreactors could be achieved corresponding to the minimum flow rate of 10 μL/min and 100 μL/min. The values of specific interfacial area remain unchanged with the increase of flow rate, and the specific interfacial area of Y-junction serpentine microreactor is much higher than that of T-junction microreactor. Maximum values of volumetric mass transfer coefficient (1.642 s-1) in the Y-junction microreactor are found several orders of magnitude higher than T-junction microchannel (0.043 s-1) and conventional extractors (0.0197 s-1).
Solvent extraction and separation of yttrium with dibenzo-18-crown-6
Separation and Purification Technology - SEP PURIF TECHNOL, 2001
A method for the spectrophotometric determination of yttrium using dibenzo-18-crown-6 is described. Yttrium forms a colourless complex with dibenzo-18-crown-6, [Y(OH)3 [L], which is extracted in dichloromethane, λmax 280 nm, molar absorptivity 1.35×104 l mol−1 cm−1. The extract is directly inserted in the plasma for ICP–AES measurement of yttrium which enhances the sensitivity to several fold with the detection limit 1 ng ml−1. The over all formation (β2K′) and distribution (Ke) constants calculated are 19.20±0.05 and 8.05±0.05×10−9, respectively. The colour was developed with xylenol orange having the λmax 555 nm with the molar absorptivity 5.48×103 l mol−1 cm−1. The system obeys Beers law in the range 0.81–16.2 μg ml−1 of yttrium. The yttrium is separated and determined in the presence of 90Sr. To check the validity of the proposed method the yttrium was determined in standard rock samples.
Separation and Purification Technology, 2019
Recycling of critical raw materials such as rare-earth elements (REEs) is increasingly crucial in the development of a sustainable economy. Separation of individual REEs (mainly yttrium and europium) from lamp phosphor waste has become essential due to the substantial stockpiling of end-of-life fluorescent lamps. The mutual separation of Y(III) and Eu(III) from aqueous chloride solutions with solvating extractants by conventional extraction methods is highly inefficient. Hence, separation of Y(III) and Eu(III) was investigated using a novel technique called "non-aqueous solvent extraction". Unlike conventional solvent extraction, the new approach uses two immiscible organic phases (more polar (MP) and less polar (LP)) instead of an aqueous and an organic phase. The present work describes a new solvometallurgical process for the separation of Y(III) and Eu(III) from ethylene glycol solutions using the solvating extractant Cyanex 923 in an aliphatic diluent. This extraction system exhibits improved separation compared to extraction from aqueous solutions. Following predictions based on a McCabe-Thiele diagram, a three-stage counter-current extraction simulation was carried out to extract Y(III) quantitatively, with 7% co-extraction of Eu(III) at a volume phase ratio of MP:LP of 1.5:1. The coextracted Eu(III) was selectively scrubbed in two stages using an Y(III) scrub solution. Y(III) was recovered from the loaded less polar organic phase by precipitation stripping with an aqueous oxalic acid solution and a subsequent calcination step. Y 2 O 3 with a purity of more than 99.9% was obtained. A complete process flow sheet, comprising extraction, scrubbing and stripping steps for the separation of Y(III) and Eu(III) is reported. The feasibility of the developed process was successfully demonstrated in continuous mode using a battery of mixersettlers.
Separation and Purification of Yttrium from Strontium Using Solvent Impregnated Resins
Yttrium-90 (Y-90) is one of radionuclides used widely for cancer treatment and it can be generated by radioactive decay of strontium-90 (Sr-90). It is essential to obtain Y-90 with high purity and free from Sr-90. Process for separation and purification of Y by extraction chromatography technique has been investigated using 2 columns of solvent impregnated resins. First column was packed with XAD-16 resin impregnated with solvent of 0.3 M di(2-ethylhexyl) phosphoric acid (D2EHPA) in dodecane and the second column was packed with XAD-16 resin impregnated with solvent of 1.0 M n-octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) in tri-n-butyl phosphate (TBP). Feed solution used in the study was the mixture of Y and Sr in 0.3 M HNO 3 having concentration of 700 and 0.2 mg/L, respectively resembling the usual composition ratio of these radionuclides used for the feed. Feed solution was loaded into the first column at 0.3 mL/min and 7 M HNO 3 was used to elute the adsorb...
Solvent extraction and recovery of Y(III) and Yb(III) from fluorspar mineral
International Journal of Minerals, Metallurgy, and Materials, 2013
Yttrium and ytterbium were extracted from sulfuric acid medium using triphenylarsine (TPAs) dissolved in kerosene. The influence of different factors, such as shaking time, extractants, metal ions, sulfate ion concentrations, as well as temperature, was studied in detail. From the slope analysis method and IR measurements, the structure of the extracted species was suggested as MSO4(HSO4)•TPAs, where M refers to Y(III) or Yb(III). The equilibrium constants (Kex) and thermodynamic parameters, such as the change in enthalpy (ΔH), free energy (ΔG), and entropy (ΔS), were calculated. The method of extraction and stripping was applied to obtain the aforementioned metals from a sample of fluorspar mineral giving a recovery yield of 88.2% and 83.5% for yttrium and ytterbium, respectively.
Radiochemistry, 2006
and Y nitrates between aqueous HNO 3 solutions and solutions of bis(dioctylphosphinylmethyl)phosphinic acid in organic diluents was studied. The stoichiometry of the extractable complexes was determined, and the diluent effect on the efficiency of extraction of rare-earth elements from nitric acid solutions was examined. Addition of a neutral solvating component, tetraphenylmethylenediphosphine dioxide, to the organic phase enhances the extraction of rare-earth elements, exerting a synergistic effect.