Simultaneous recovery of rare earths and uranium from wet process phosphoric acid using solvent extraction with D2EHPA

In most cases, wet-process phosphoric acid (WPA) contains trace amount of rare earth elements and uranium, which ultimately enter and accumulate in soil and may cause environmental damages. In order to remove and recover these elements, studies about solvent extraction of heavy rare earth elements (HREEs) and uranium (U) with D2EHPA, selective stripping of HREE5 from U, and evaporation precipitation of light rare earth elements (LREEs) were investigated. Extraction efficiency of U from WPA was greatly enhanced, but HREEs extraction were significantly retarded when using the solvent mixture of di- (2-ethylhexyl) phosphoric acid (D2EHPA) and tri-butyl-phosphate (TBP) or tri-octyl-phosphine oxide (TOPO) compared with D2EHPA alone. 89A% and 94.2% accumulative two-stage extraction efficiencies of HREEs and U, respectively, were achieved with 1.0 M D2EHPA alone. And more than 98.1% HREE5 were selectively stripped from loaded D2EHPA with 6.0 M HC1 via three stages. In addition, LREEs were enriched to 1204.3 mu g/g in evaporation sludge during the concentration process of phosphoric acid from 30% to 50% P2O5, and the filtration performance was greatly improved. Based on the studies, an alternative process was developed to recover and group LREEs, HREE5 and U during the phosphoric acid production.