Multicomponent separation by a combined extraction/electrostatic pseudo-liquid membrane (II): extraction and group separation of rare earths from simulated rare earth ore leach solutions

Abstract

The extraction of rare earths (REs) from simulated RE ore leachate solutions using an electrostatic pseudo-liquid membrane (ESPLIM) was carried out, followed by group separation of REs by a combined extraction/ESPLIM on the basis of previous work on the separation of Al, La, Sm and Y. The ESPLIM set-up was modified in such a way that gradient stripping could be easily applied. A simulated RE ore leachate containing about 1.0 g/l mixed rare earth elements (REEs), 10 g/l (NH 4) 2SO 4, 5 g/l NH 4Cl and 0.6 g/l of non-RE ions such as Ca, Al, Si, Fe and Pb was treated using di-(2-ethylhexyl) phosphoric acid (HDEHP) as carrier in the organic membrane phase. The influences of feed pH, flow rate of feed, stripping and organic phases, and stripping acid concentration were investigated. RE extraction percentage >95% and preliminary group separation and preconcentration of RE were achieved.