Solvent Extraction Of Pr Research Articles

Solvent extraction of praseodymium using different extractants – a synergistic study

ABSTRACTThe extraction of praseodymium was investigated from chloride media using different extractants such as D2EHPA, PC88A, Cyanex 272, Cyanex 921, Cyanex 923, Cyanex 301, Cyanex 302, LIX 84I, LIX 622N, Alamine 336, Aliquat 336 and their mixtures. The synergistic effect of Cyanex 272, Cyanex 921, Cyanex 923, Cyanex 301 and Cyanex 302 were studied with each other. Among all the combinations, the mixtures of Cyanex 921-Cyanex 301 and Cyanex 923-Cyanex 301 showed the synergistic effect on the extraction of praseodymium. Solvent extraction of Pr was carried out with the mixture of 0.5 M Cyanex 301 and 0.5 M Cyanex 923. The McCabe-Thiele diagram indicated the quantitative extraction of Pr in two counter-current stages at an A:O phase ratio of 1:2. The two-stage counter-current simulation study showed 94% of extraction efficiency.

Solvent Extraction of Pr and Nd from Chloride Solution by Mixtures of Acidic Extractants and LIX 63

Mixtures of acidic extractants and LIX 63 were employed to improve the extraction efficiency of Pr and Nd from chloride solutions. The effect of the composition of the extractant mixtures has been studied. The order of metal extraction by single acidic extractant was D2EHPA > PC88A > Cyanex 272 > Cyanex 301. The addition of LIX 63 to the acidic extractants resulted in a synergistic effect, and the strength of the effect was the reverse order of that found for extraction by single extractants. Moreover, mixing of saponified Cyanex 272 and LIX 63 enhanced the extraction, while the addition of Alamine 336 to the mixtures of Cyanex 272 and LIX 63 depressed the extraction. (Received November 17, 2015; Accepted March 24, 2016)

Solvent extraction of Pr and Nd from chloride solutions using ternary extractant system of Cyanex 272, Alamine 336 and TBP

Synergistic extraction and separation of Pr and Nd in chloride medium using a ternary mixture containing Cyanex 272, Alamine 336 and TBP has been investigated. Compared to the binary mixture (Cyanex 272+Alamine 336), the ternary mixture showed a remarkable synergism on metals and increased the separation factor. The highest synergistic enhancement factors were obtained for Pr (17.0) and Nd (14.6). The mechanism of the synergistic extraction reaction and the role of Alamine 336 and TBP in reaction were proposed. Furthermore, metals in the ternary mixture were easily stripped by using HCl or H2SO4 solution with lower acidity.

Solvent extraction of Pr and Nd from chloride solution by the mixtures of Cyanex 272 and amine extractants

In the separation of rare earth elements by solvent extraction with organophosphorus extractants, bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) leads to lower extraction percentage but higher separation factor. In order to increase the extraction of Pr and Nd by Cyanex 272, its mixtures with amine extractants, such as tri-octyl/decyl amine (Alamine 336), trioctylamine (TOA) and tri-2-ethylhexyl amine (TEHA) have been employed from chloride solution. Among the studied extractant mixtures, the combination of Cyanex 272 and Alamine 336 showed that the best extraction ability and the maximum synergistic enhancement factors were 14.2 for Pr and 12.2 for Nd at Cyanex 272 mole fraction of 0.5. The role of Alamine 336 in this mixture was to extract hydrogen ions released from Cyanex 272. The overall solvent extraction reaction was identified by applying a slope analysis method to the experimental data. Moreover, it was found that the concentration ratio of Alamine 336 to chloride ion affected the enhancement in the extraction of the two metals. The quantitative stripping of both Pr and Nd was possible from the loaded mixture by using HCl or H2SO4 solution.

Separation of Nd from mixed chloride solutions with Pr by extraction with saponified PC 88A and scrubbing

Solvent extraction of Pr and Nd from chloride solution was carried out using PC 88A for the recovery of magnetic grade Nd. The presence of complexing reagents (H2O2 and citric acid) affected little the selective extraction of Nd over Pr. The observed maximum separation factor between Pr and Nd was 1.5, indicating that the separation of Nd and Pr by selective extraction was difficult. Co-extraction of two metals with PC 88A followed by selective scrubbing was tried. Batch simulation of counter-current showed that the complete recovery of Nd was possible and a process flow sheet has been presented.

Effect of diluents on the extraction of praseodymium and samarium by Cyanex 923 from acidic nitrate medium

The solvent extraction of Pr(III) and Sm(III) with trialkyl phosphine oxide (Cyanex 923) in chloroform, carbon tetrachloride, n-octane, cyclohexane, 1,2-dichloroethane, benzene, toluene, xylene and nitrobenzene from acidic nitrate medium was investigated. On the basis of slope analysis data, the composition of the extracted species was determined as (M(NO 3) 3·2CY923), CY923 refers to Cyanex 923. The values of the equilibrium constants and the separation factors were calculated. The effect of the diluents on the metal extraction and separation was discussed and correlated to the physical constants of the diluents. The results showed that with increasing dielectric constant of the diluent, the extraction percent decreased while the separation factors did not change considerably.

Solvent extraction of Pr and Nd (III) from chloride-acetate medium by 8-hydroquinoline with and without 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester as an added synergist in heptane diluent

In this paper, solvent extraction of Pr (III) and Nd (III) using 8-hydroxyquinoline in chloride-acetate medium has been systematically investigated. The effect of various parameters, such as equilibrium time, aqueous pH, extractant concentration, acetate ion concentration, chloride ion concentration, and organic solvent, on the extraction has been discussed. The synergistic effect in the mixtures of 8-hydroxyquinoline (HQ) and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) has been explored, and the largest synergistic enhancement factor has been calculated. The separations of Pr (III), Nd (III) and La (III) by 8-hydroquiloline alone and by mixtures of HQ and P507 have been studied, and the results demonstrate that it is possible to separate Pr (III), Nd (III) and La (III) with the mixtures of HQ and P507. At last, the stripping of Pr, Nd and La (III) has been performed.

Extraction and separation of thorium(IV) and praseodymium (III) with CYANEX 301 and CYANEX 302 from nitrate medium

Solvent extraction of Pr(III) and Th(IV) has been investigated with commercial extractants of CYANEX 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid) and CYANEX 302 (bis(2,4,4-trimethylpentyl) monothiophosphinic acid) in kerosene from nitrate medium. The effects of various parameters affecting the extraction equilibrium of Th(IV) and Pr(III), including temperature, were studied and the stoichiometry of the extracted Th(IV) and Pr(III) species was elucidated. The separation of Th(IV) from Pr(III) depending on the difference in the extraction behavior of the two extractants towards these metals is given and discussed.

INFLUENCE OF THE AMMONIUM SALT ANION ON THE SYNERGISTIC SOLVENT EXTRACTION OF LANTHANIDES WITH MIXTURES OF THENOYLTRDJLUOROACETONE AND TRIDECYLAMINE

ABSTRACT The synergistic solvent extraction of Pr, Gd and Yb with mixtures of thenoyltnfluoroacetone ( HTTA) and primary ammonium salt ( tridecylammonium chloride or perchlorate, TDAH( C1, CI0) in dHhas been studied. The composition of the extracted species have been determined as Ln( TTA)3 TDAHA( A= CI or CIO4 ) The values of the equilibrium constant KT. s have been calculated. The influence of the ammonium salt anion on the extraction process has been discussed. The separation factors of the pairs Gd/ Pr and Yb/ Gd have been determined.

Synergistic solvent extraction of lanthanides with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one and aliphatic amines: Influence of the ammonium salt ions

The synergistic solvent extraction of Pr, Gd, and Yb with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and tridodecylammonium (TDAHA), trioctylammonium (TOAHA), and dioctylammonium (DOAHA) salts (A −=Cl−, NO 3 − , and ClO 4 − ) in C6H6 has been studied. The composition of the extracted species has been determined asAmH+[LnP 4]− (AmH+: ammonium salt cation). The values of the equilibrium constant have been calculated. The influence of the ammonium salt ions on the extraction process is discussed.

SOLVENT EXTRACTION OF SOME TERVALENT LANTHANOIDS WITH N-PENTAFLUOROBENZOYL-N-PHENYLHYDROXYLAMINE

ABSTRACT A new extraction agent, N-pentafluorobenzoyl-N-phenylhydroxylamine (PFBPHA), was synthesized. The solvent extraction of Pr (II), Eu (II) and Yb (II) with PFBPHA has been investigated at an ionic strength of 0.2 and 25 ±1°C It. The acid dissociation constant, KD, and the partition coefficient, KD, of its metal complexes were determined. These results obtained were compared with those of N-benzoyl-N-phenylhydroxy1amine (BPHA) reported previously. The introduction of fluoro group to the C-phenyl ring of BPHA was very effective for increasing not only the Ka value of PFBPHA but also its KD value and the extraction constant, KBX, of its lanthanoid complexes.

INFLUENCE OF THE AMINE SALT ANION ON THE SYNERGIC SOLVENT EXTRACTION OF PRASEODYMIUM WITH MIXTURES OF CHELATING EXTRACTANTS AND TRIDODECYLAMINE

ABSTRACT The solvent extraction of Pr with thenoyltrifluoroacetone (HTTA) or 1 -phenyl-3-methyl-4-benzoyl-pyrazol-5-one(HP) and tridodecylammonium salt (TDAHA,A− = Cl−,NO3 −ClO4 −) in C6H6 has been studied. The composition of the extracted species has been determined as Pr(TTA)3TDAHA and TDAH+[PrP4] −.The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed on the basis of the experimental data.

Peculiarities of the synergistic solvent extraction of lanthanides with mixtures of chelating extractants and tridodecylamine

The synergistic solvent extraction of Pr, Gd, and Yb with mixture of thenoyltrifluoroacetone (HTTA) or 1-phenyl-3-methyl-benzoyl-pyrazol-5-one (HP) and tridodecylammonium chloride (TDAHCl) in C6H6 has been studied. The composition of the extracted complexes has been determined asLn(TTA)3TDAHCl andTDAH+[LnP4]−. The values of the equilibrium constants have been calculated. Some peculiarities of the synergistic extraction process are discussed.

Synergic extraction of Pr(III), Ho(III) and Er(III) with a mixture of 2-thenoylltrifluoroacetone and tribenzylamine

Synergic solvent extraction of Pr(III), Ho(III) and Er(III) was carried out at pH≤3.5 with a mixture of 2-thenoyltrifluoroacetone (HTTA) and tribenzylamine (TBA) from perchlorate media, having ionic strength 0.1M(H+, ClO 4 − ). The stoichiometmric composition of all three synergic adducts was established to be Pr(TTA)3·3TBA, Ho(TTA)3·3TBA and Er(TTA)3·3TBA. The formation constants KTTA and Ksyn and stability constant ±syn were also computed and found to be in the order Er≥Ho>Pr. The effect of various anions on the extraction has also been studied.

SYNERGISTIC SOLVENT EXTRACTION OP LANTHANIDES WITH MIXTURES OF 1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOL-5-ONE AND TRI-N-OCTYLAMINE

ABSTRACT The synergistic solvent extraction of Pr, Gd and Yb with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyra-zol-5-one and tri-n-oetylamine in CC14C6H6 and CHCl3has been studied The composition of the extracted species has been determined as LnP4TOAH (Ln=Pr, Gd, Yb and P- and TOAH* are the chelating extractant anion and the amine salt cation respectively).The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed.

TEMPERATURE EFFECT ON THE SYNERGISTIC SOLVENT EXTRACT ION OF LANTHANOIDES

ABSTRACT The synergistic solvent extraction of Pr, Gd and Yd with mixtures of HTTA and Aliquat 336 in CCl4C6H6 and CHCl3 at 288,298,308 and 318 K has been studied. The values of the equilibrium constants as well as the values of the thermodynamic parameters have been calculated.

SYNERGISTIC SOLVENT EXTRACTION OF LANTHANIDES WITH MIXTURES OF 1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOL-5-ONE AND ALIQUAT 336

ABSTRACT The solvent extraction of Pr(III),Gd(III) and Yb(III) With 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and Aliquat 336(QCl) in CCl4.C6H6 and CHCl3, has been studied.The composition of the extracted species has been determined as LnP4 −.Q+ (Ln=Pr,Gd and Yb).The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed.

SOLVENT EXTRACTION OF SOME LANTHANIDES WITH MIXTURES OF 1-PHENYL-3-METHYL-4-BENZOYL-FYRAZOL-5-ONE AND 1-(2-PYRIDYLAZO)-2-NAPHTOL

ABSTRACT The solvent extraction of Pr(IIl),Gd(III) and Yb (III) with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (PMBP,HP) and with mixtures of PMBP and 1-(2-pyridyl-azo)-2-naphtol(PAN,S) in-CCI⊂4⊂,C⊂6⊂H⊂6⊂ and CHCI⊂3⊂, has been studied..The composition of the extracted complexes has been determined as LnP⊂3⊂.HP and LnP⊂3⊂.S(Ln=Pr,Gd and Yb) The values of the equilibrium constants have been calculated.Weak synergistic effects were found when the metals were extracted with mixtures of the extractants

Temperature effect on the solvent extraction of some lanthanides with thenoyltrifluoroacetone

The solvent extraction of Pr, Gd and Yb with thenoyltrifluoroacetone solutions in C6H6, CHCl3 and CCl4 at 288 K, 298 K, 308 K and 318 K has been investigated. The values of the equilibrium constant have been calculated as well as the values of the thermodynamic parameters ΔH, ΔS and ΔG. The temperature effect on the solvent extraction of lanthanides with thenoyltrifluoroacetone is discussed.