An innovative technique for the separation of ion-adsorption high yttrium rare earth ore by Er (III) / Tm (III) grouping first

Abstract

The current separation technique of ion-adsorption high yttrium (Y) rare earth ore (high-yttrium ore) using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) and naphthenic acid (NA) has been confronted with low separation efficiency and high acid consumption. This is a consequence of the low selectivity and the difficulty of complete stripping of heavy rare earths (HREEs). Therefore, an innovative separation technique of high-yttrium ore was proposed. The leachate of high-yttrium ore was firstly divided into Erbium (Er) / Thulium (Tm) groups with P507-isooctanol followed by separating Y (III) from the high Y-enrichment of Er (III) group with sec-octylphenoxy acetic acid (CA12)-tri-n-butyl phosphate (TBP). The basic thermodynamics experiments and cascade extraction simulations were conducted to verify the feasibility of this technology. The results show that P507-15vol% isooctanol is superior to P507 in both stripping ability and separation selectivity of HREEs. The first cascade extraction for Er (III) / Tm (III) grouping with P507-15vol% isooctanol was simulated successfully, reducing acid consumption but obtaining high purity products. In theory, the second cascade extraction simulation designed for separating Y (III) with CA12-TBP could not only improve the separation ability between Y (III) and light rare earths (LREEs) but also shorten the extraction stages and reduce the production costs. All these results revealed that this two-step separation process probably provided a promising application prospect for separating high-yttrium ore.