Improved Extraction of Rare Earths of La, Ce, Pr, and Nd by Optimizing the Structure of Phenoxyacetic Acid

Abstract

A novel extractant, 2‐(2‐heptanoylphenoxy)acetic acid (HA), was synthesized and applied to extract La, Ce, Pr, and Nd from the hydrochloric acid solution. The extraction parameters including pH, temperature, concentrations of HA and chloride ion were investigated and discussed in detail. The extraction mechanism was studied with Fourier‐transform infrared (FT‐IR) spectroscopy. Compared with the extractant of sec‐octylphenoxy acetic acid (CA12), HA showed excellent performance and different extraction order in extracting La, Ce, Pr, and Nd. All the rare‐earth metals (REs) were extracted by the cation exchange mechanism and loaded as REs(A)3. The stripping test showed that the loaded REs in the organic phase can be effectively stripped with sulfuric acid at medium acidity. This work revealed that HA is an effective extractant for REs.

A Synergistic Extraction for the Separation of Scandium with Cyanex572 and Cyanex923

“…[17][18][19][20] Numerous extractants can be utilized for the separation of Sc and rare earths, such as bis-(2-ethylhexyl) phosphoric acid(P204), Cyanex923(C923) and bis(2,4,4-trimethylpentyl) phosphonic acid(P507). [21][22][23][24][25] Among those commercial extractants, Cytec Industries' C923 has demonstrated good selectivity for Sc. [26] However, the excellent extraction performance of C923 can only be achieved under high acidic conditions.…”