SELECTIVE EXTRACTION OF VANADIUM (V) FROM SOLUTIONS CONTAINING MOLYBDENUM (VI) BY AMMONIUM-SALTS DISSOLVED IN TOLUENE

Several separation schemes, involving liquid-liquid extraction procedures, were found to be theoretically feasible in order to separate Vanadium and Molybdenum based on computer simulation of the acid-base properties of these metals, where cationic and anionic (both mono and polynuclear) species are formed as the pH increases. A liquid cationic extractant (LIX 26), a basic alkylamine (Alamine 336) and a quaternary ammonium salt (Aliquat 336) were experimentally tested. Among them, the sulphate of the quaternary ammonium salt extracts V(V) selectively and quantitatively from Mo(VI) solutions in the basic range 8 < pH < 9. A close relation between the extraction of the metals and the distribution of their species in the aqueous phase has been found. The sulphate forms of Alamine 336 and Aliquat 336 extract quantitatively both metals at the pH where anionic polynuclear species are predominant.