STUDY OF THE SOLVENT EXTRACTION OF THE LIGHTER LANTHANIDE METAL IONS BY MEANS OF ORGANOPHOSPHORUS EXTRACTANTS

In recent years there has been a great demand for rare earth metals because of their unique physical and chemical properties as new constituents for electronic, optical and magnetic devices. Because oftheir extremely similar chemical and physical properties, it is very difficult to separate them. A study ofsolvent extraction oflighter lanthanide metal ions with a family of organophosphorus extractants, commercially known as D2EPHA, PC88A, CYANEX 272 and CYANEX 301, was made. In general it was found that praseodymium ions were extracted with all the extractants, while in decreasing order neodymium, cerium and lanthanum were extracted less efficiently. Moreover, the D2EHPA and PC88A showed higher extraction efficiencies over the whole pH range used, but they did not allow an effective separation ofREE ions. Furthermore, with CYANEX 301 some degree ofseparation ofthe metal ions was achieved, but the extraction efficiencies were comparatively lower. On the contrary, using the CYANEX 272 extractant, medium efficiencies of extraction were achieved, but with a lower ability to separate the REE ions.