Efficient separation of yttrium(III) from high-grade yttrium concentrate by solvent extraction with 2-hexyldecanoic acid

Yttrium (Y) is extensively utilized in various industries for its excellent optical, electrical, and magnetic properties. However, the separation between Y and other rare earth elements (REEs) is difficult, because the properties of Y are very similar to other REEs. To overcome the drawbacks of traditional extractants, such as complex structural composition and poor stability, it is important to develop new extractants for separating Y. Featured in this study is a novel carboxylic acid extractant, 2-hexyldecanoic acid (DY319, HA), employed for extraction and separation of Y. The pK a value of DY319 is 7.54. The extraction sequence of REEs with DY319 is as follows: Lu > Yb > Eu > Tm > Er > Ho ≈ Tb > Dy > Pr > Gd > Nd ≈ Sm > Ce > Y > La. Additionally, the extraction parameters, including the extractant concentration, saponification degree, phase volume ratio, equilibration time, and temperature, were carefully studied. The separation factors of separating Y from other REEs were measured, and the separation factors between Y and Ho, Er, Tm, Yb, Lu are 2.37, 2.46, 3.05, 4.05, and 4.12, respectively. Moreover, it exhibits excellent recyclability and loading capacity. Quantitative stripping can be accomplished with HCl by single-stage stripping. Through a cascade extraction process with 16-stage extraction and 4-stage scrubbing, the Y product with 99.9 wt% purity was obtained. Ultimately, the extraction process is governed by the cation exchange reaction, and the extraction complex was deduced to be REA 3 .