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Synergistic extraction of rare earths(III) from chloride medium with mixtures of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate
Author(s) -
Zhao Junmei,
Meng Shulan,
Li Deqian
Publication year - 2006
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.1572
Subject(s) - chemistry , enthalpy , extraction (chemistry) , gibbs free energy , stoichiometry , rare earth , chloride , standard enthalpy of formation , nuclear chemistry , thermodynamics , chromatography , organic chemistry , mineralogy , physics
The synergistic effect of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 (HPMBP, HA) and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y 3+ , and taking Yb 3+ and Y 3+ as examples, RE 3+ is extracted as RE(OH)A 2 .B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change Δ G (−17.06 kJ mol −1 ), enthalpy change Δ H (−35.08 kJ mol −1 ) and entropy change Δ S (−60.47 J K −1 mol −1 ) for Y 3+ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry