Patent GB-1006899-A (GB)
Title: Separation of europium from other rare earths by solvent extraction
IPC: C01F17/17
Filed: 1962-06-04
Abstract: Europium values are separated from other rare-earth values (as defined) by contacting, e.g. at 25 DEG  C., a solution of an acidic ester of phosphoric or phosphonic acid in carbon tetrachloride or aromatic water-immiscible hydrocarbons, with an aqueous solution containing a chromium III salt, e.g. CrCl3; either of which solutions may contain the rare earth and Eu values and to this solution is added a zinc amalgam with subsequent separation of the organic phase containing the trivalent rare earth from the aqueous phase containing Eu. Rare earths are defined as (a) lantanide rare earths, (b) Sc & Y, and (c) actinide rare earths which are trivalent in their principal valence state or in their normal valence state in aqueous solution, such as Am, Cm & Cf.  The chromic chloride solution may have a concentration of 0.001 to 0.01M and sufficient Zn amalgam, e.g. containing 0.5% Hg, may be added to reduce all Eu present.  Examples of the aromatic hydrocarbons are benzene, xylene, but preferably toluene.  The acidic esters may be present in concentrations of 0.01 to 1.5F (Formality) and may be of the type (RO)2 PO(OH) and (G1O)(G)PO(OH) where R is alkyl, aryl and alkaryl, G an organic group or radical, and G1 an organic group; R, G and G1 preferably having at least 4C atoms each, to obtain a compound that has high water immiscibility, e.g. 2 ethyl-hexyl, n-octyl, monochloro-methyl and phenyl.  Both the organic and aqueous solutions whose volume ratio may range from 20 : 1 to 1 : 20 may be flushed with an inert gas, e.g. N2 to remove all O2 and the contacting process carried out in an inert atmosphere. The rare earths in the organic solution may be back extracted into an aqueous solution by treatment with 2.5N HCl and Zn present in the aqueous solution may be removed by contact with tributyl phosphate.  Likewise Eu may be separated from Cr in the aqueous solution by oxidation with air and extraction with an organic solution of an acidic ester of phosphoric or phosphonic acid.  The separation of Eu from Pm, Sm, lanthanides including Y; 241Am, Cm and Cf are disclosed.ALSO:Europium values are separated from other rare-earth values (as defined) by contacting, e.g. at 25 DEG  C., a solution of an acidic ester of phosphoric or phosphonic acid in carbon tetrachloride or aromatic water-immiscible hydrocarbons, with an aqueous solution containing a chromium III salt, e.g. CrCl3; either of which solutions may contain the rare earth and Eu values and to this solution is added a zinc amalgam with subsequent separation of the organic phase containing the trivalent rare earth from the aqueous phase containing Eu. Rare-earths are defined as (a) lanthanide rare-earths, (b) Sc and Y, and (c) actinide rare-earths which are trivalent in their principal valence state or in their normal valence state in aqueous solution, such as Am, Cm and Cf.  The chromic chloride solution may have a concentration of 0.001 to 0.01 M and sufficient Zn amalgam, e.g. containing 0.5% Hg, may be added to reduce all Eu present.  Examples of the aromatic hydrocarbons are benzene, xylene, but preferably toluene.  The acidic esters may be present in concentrations of 0.01 to 1.5 F (Formality) and of the type (RO)2PO(OH) and (G1O)(G)PO(OH) where R is alkyl, aryl and alkaryl, G an organic group or radical, and G1 an organic group; R, G and G1 preferably having at least 4C atoms each, to obtain a compound that has high water immiscibility, e.g. 2 ethylhexyl, n-octyl, monochloro-methyl and phenyl. Both the organic and aqueous solutions whose volume ratio may range from 20 : 1 to 1 : 20 may be flushed with an inert gas, e.g. N2 to remove all O2 and the contacting process carried out in an inert atmosphere.  The rare-earths in the organic solution may be back extracted into an aqueous solution by treatment with 2.5 N HC1 and Zn present in the aqueous solution may be removed by contact with tributyl phosphate.  Likewise Eu may be separated from Cr in the aqueous solution by oxidation with air and extraction with an organic solution of an acidic ester of phosphoric or phosphonic acid.  The separation of Eu from Pm, Sm, lanthanides including Y; 241Am, Cm and Cf are disclosed.