Reactive & Functional Polymers 49 (2001) 189–195 www.elsevier.com / locate / react Extraction of rare earth elements with 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate impregnated resins having different morphology and reagent content 1 * Hideyuki Matsunaga , Adel Ali Ismail , Yoshito Wakui, Toshirou Yokoyama 2 Tohoku National Industrial Research Institute,4-2-1 Nigatake, Sendai 983-8551, Japan Received 3 August 2000; accepted 29 May 2001 Abstract Extraction of rare earth elements (REEs) with reagent impregnated resins (RIRs) using 2-ethylhexyl hydrogen 2- ethylhexyl phosphonate (PC-88A) and Amberlite XAD-2, XAD-4, XAD-16 and XAD-7 as a polymeric support has been studied. The impregnated resins containing various amounts of PC-88A have been prepared by a dry method. The effect of contact time on the extraction of REEs with PC-88A impregnated resins (PC-88A–resin 5 20 / 80, 50 / 50 wt.%) at pH 3.5 has been chiefly investigated. It was found that the extraction becomes slow when an insufficient amount of PC-88A was impregnated into XAD-2, XAD-4 or XAD-16 resins with respect to their pore volume. Little effect of the amount of PC-88A in XAD-7 on the rate of extraction was observed. The presence of n-dodecane improves the extraction kinetics for XAD-4 and XAD-16 at a small PC-88A content. It is speculated that PC-88A should be filled in the pore of the resin from the bottom to the top under the present impregnation process. It is thus recommended to make RIRs with enough of the reagent to fill up the pores of hydrophobic resins in this impregnation method.  2001 Elsevier Science B.V. All rights reserved. Keywords: PC-88A impregnated resins; Extraction of rare earth; Effect of resin morphology; Effect of PC-88A content sufficient separation. Reagent impregnated res- 1. Introduction ins (RIRs) are relatively new types of ion Solvent extraction has been widely used as a selective exchangers based on the solvent ex- basic technique for the separation of metal ions traction [1,2]. An RIR has some potential from aqueous solutions. Separation via solvent advantages over solvent extraction applied to extraction, however, often practically requires hydrometallurgical processes due to its high multistage cycles of extraction to attain the selectivity, high concentration ratio and ease of preparation as well as handling. In our previous studies, the extraction of rare earth elements (REEs) was successfully carried *Corresponding author. Tel.: 181-22-2375-211; fax: 181-22- out with 2-ethylhexyl hydrogen 2-ethylhexyl 2375-215. E-mail address: hide.matsunga@aist.go.jp (H. Matsunaga). phosphonate (PC-88A) impregnated Amberlite 1 On study leave from Central Metallurgical Research and De- XAD-7 [3,4]. Among the extractants commonly velopment Institute, Cairo, Egypt. 2 employed in the solvent extraction of REEs, Present name: National Institute of Advance Industrial Science and Technology, Tohoku. PC-88A is known to possess advantages of high 1381-5148 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S1381-5148(01)00077-3