- Reducing the competition: A dual-purpose ionic liquid for the extraction of gallium from Iron Chloride solutions
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The separation of gallium from iron by solvent extraction from chloride media is challenging because the anionic chloridometalates, FeCl4? and GaCl4?, display similar chemical properties. However, we report here that the selective separation of gallium from iron in HCl solution can be achieved using the dual-purpose ionic liquid methyltrioctylammonium iodide in a solvent extraction process. In this case, the reduction of Fe3+ to Fe2+ by the iodide counterion was found to inhibit Fe transport, facilitating quantitative Ga extraction by the ionic liquid with minimal Fe extraction from 2 M HCl.
- Kinsman, Luke M. M.,Love, Jason B.,Morrison, Carole A.,Ngwenya, Bryne T.
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- Extraction of zinc and copper with acetylenic quaternary ammonium salts
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Extraction of zinc(II) and copper(II) from HCl solutions with solutions of mono- and dialkynyl-substituted quaternary ammonium halides in chloroform and toluene is more efficient than the extraction with saturated quaternary ammonium salts and occurs by different mechanism. The dependences of the metal distribution factors on the HCl concentration have two maxima whose positions (absolute and relative) and relative intensities depend on the particular extractant, metal, and diluent. 2005 Pleiades Publishing, Inc.
- Andreev,Tunina,Remizova
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- Separation of precious metals by split-anion extraction using water-saturated ionic liquids
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A split-anion solvent extraction process was developed for the separation of precious metal ions Au(iii), Pt(iv), Pd(ii) and Rh(iii) from aqueous chloride media using water-saturated ionic liquids. The metal extraction and stripping behavior of the chloride form [A336][Cl], bromide form [A336][Br] and the iodide form [A336][I] of the quaternary ammonium ionic liquid Aliquat 336 were compared. The three ionic liquids extracted Au(iii), Pd(ii) and Pt(iv) quantitatively in most cases, whereas the co-extraction of Rh(iii) was strongly dependent on the acidity and the chloride concentration. Among the studied ionic liquids, [A336][I] achieved the highest separation factors between Pd(ii)/Rh(iii), Pt(iv)/Rh(iii), and Au(iii)/Rh(iii) at 6 mol L-1 Cl-. Additionally, the selective stripping of the individual metal ions Pd(ii), Au(iii), and Pt(iv) was only possible from loaded [A336][I] using ammonia solution (NH4OH), sodium thiosulfate (Na2S2O3), and thiourea ((NH2)2CS), respectively. A closed-loop flow sheet was designed for the recovery of the precious metals from chloride media using split-anion extraction with [A336][I]. The integrated process was demonstrated to be suitable for the purification of Rh(iii), Pt(iv) and Pd(ii) from a complex metal feed such as the leachate of spent automotive catalysts. The ionic liquid-based split-anion extraction process is simple, selective and effective for the sustainable separation of the precious metals, using only one green extractant [A336][I], which can be regenerated for consecutive extraction-stripping cycles.
- Nguyen, Viet Tu,Rian?, Sofiá,Binnemans, Koen
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p. 8375 - 8388
(2020/12/29)
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