Solvent Extraction of Didymium by TBP, Aliquat 336 and HDEHP in The Presence of Ca(NO3)2

Petr I Matveev,Vladimir G Petrov

doi:10.3390/app10062032

Abstract

Three commercially available extractants (tri-butyl-phosphate (TBP), di-(2-ethylhexyl)phosphoric acid (HDEHP) and Aliquat 336 (a mixture of quaternary ammonium bases)) were tested for separation of Pr(III) and Nd(III) in both static and dynamic modes. In the case of HDEHP, phase stability and influence of nitric acid were considered. Extraction isotherms were constructed, and influence of water-soluble complexing agents on the separation factor was investigated for Aliquat 336. In the case of TBP, influence of calcium nitrate in aqueous phase on the extraction efficiency was investigated. Model countercurrent experiments were conducted for TBP and Aliquat 336. It was shown that TBP is the best choice due to its high capacity and cation extraction order (Nd > Pr).

Highlights

Rare earth elements (REEs) are a group consisting of lanthanides as well as yttrium and scandium
One of the preferable ways to separate REEs and to isolate individual elements is with liquid–liquid extraction
We have shown that calcium nitrate can be used as an effective salting-out agent [18] for the REE separation in the system “100% TBP–nitric acid solutions of REE(NO3 )3 ”

Summary

Introduction

Rare earth elements (REEs) are a group consisting of lanthanides as well as yttrium and scandium. Most part of these elements demonstrate unique physical properties that are used in a wide range of high-tech industries. In many cases (e.g., production of luminescent and magnet materials, additives in nuclear fuels, etc.), implementation of an individual pure REE is required. From a chemical point of view, all of these elements possess very close chemical properties: the same oxidation state (+3), the same character of electronic shells ([Xe]4fn 5d1 6s2 for lanthanides) and close values of ionic radii. Separation of rare earth elements is a complex chemical and technological task. One of the preferable ways to separate REEs and to isolate individual elements is with liquid–liquid extraction

Objectives

Methods

Results