Solvent extraction studies of Sm(III) from nitrate medium and separation factors of rare earth elements with mixtures of sec‐octylphenoxyacetic acid and 1,10‐phenthroline

Abstract

BACKGROUND: Liquid-liquid extraction is widely used for the separation of rare earths, among which synergistic extraction has attracted more and more attention. Numerous types of synergistic extraction systems have been applied to rare earths with high extraction efficiency and selectivities. In the present study, mixtures of sec-octylphenoxyacetic acid (CA12, H 2 A 2 ) and 1,10-phenanthroline (phen, B) have been used for the extraction of rare earths from nitrate medium. The stoichiometry of samarium(III) extraction has been studied using the methods of slope analysis and constant molar ratio. The possibility of using synergistic extraction effects to separate rare earths has also been studied.

Process Flowsheet Development for Separation of Sm, Co, Cu, and Fe from Magnet Scrap

“…Besides precipitation, several studies on solvent extraction as an effective route for separation of Sm were reported. − Processing of a SmCo magnet for recovery of Sm and Co, and separation of Sm using CYANEX 572 from chloride leach liquor, was reported . The authors demagnetized the waste magnet by roasting at 1123 K prior to leaching with 4 M HCl at 368 K under 100 g/L S:L. Precipitated Sm and Co oxalates were calcined to produce oxides of Sm and Co.…”

“…The addition of D2EHPA to the CYANEX 301 extraction system increased the extraction efficiency of CYANEX 301 with better stripping in the low concentration range. In another study, a mixture of sec-octylphenoxyacetic acid and 1,10-phenthroline was used for extraction of Sm and other REEs from a synthetic solution in nitrate medium . A comparative study on separation of Co (II) and Sm (III) by dissolving their chloride salts in water as well as in ethylene glycol (EG) in the presence of LiCl was studied .…”

“…In another study, a mixture of sec-octylphenoxyacetic acid and 1,10phenthroline was used for extraction of Sm and other REEs from a synthetic solution in nitrate medium. 17 A comparative study on separation of Co (II) and Sm (III) by dissolving their chloride salts in water as well as in ethylene glycol (EG) in the presence of LiCl was studied. 18 Aliquat 336 was used for extracting both Co and Sm from aqueous solution.…”

Synergistic extraction and separation study of rare earth elements from nitrate medium by mixtures of sec-nonylphenoxy acetic acid and 2,2′-bipyridyl

“…Over recent decades, synergistic extraction systems have been applied many times to the separation of REEs. Various mixtures of two extractants have been investigated for the extraction of REEs, including carboxylic acids,1, 5, 7–18 acidic organophosphorous extractants,19–21 neutral organophosphorous extractants,22–24 crown ethers,25, 26 and amines (ammonium salts) 27. Among these reagents, CA100 has been proved to be an excellent synergistic extractant.…”

“…The formation of mixed ligand chelates involving the chelating extractants and various adducts not only provide better extractability, but also improve separation. The extraction of REEs from acidic nitric solutions with binary mixtures of 1, 10‐phenanthroline (phen) with sec ‐octylphenoxyacetic acid (CA12) and CA100 have been studied in the laboratory 7, 16. 2,2′‐bipyridyl (bipy) has a similar structure to phen, and has also proven to be an excellent synergistic.…”