LANTHANUM SOLVENT EXTRACTION MECHANISMS USING DI-(2-ETHYLHEXYL) PHOSPHORIC ACID

The equilibrium extraction mechanism of lanthanum nitrate from aqueous solutions by purified water equilibrated di-(2-ethylhexyl) phosphoric acid was studied at 25°C through material balance analysis of equilibrium phases. No organic diluent was used, and the lanthanum nitrate concentration in the neutral aqueous phase varied from 10 to 40 per cent by weight. Equilibrium data for lanthanum distributed between di-(2-ethylhexyl) phosphoric acid and water were gathered and used to determine complex formations and reaction stoichiometry. Infrared spectral analysis of several organic phase samples supported the material balance data and verified the movement of water molecules from the organic phase to the aqueous phase as lanthanum entered the organic layer. Three predominant extraction mechanisms involving pure lanthanum ions and partially nitrated lanthanum ions were prescribed from the experimental data. © 1969.