| Author(s) |
Nikki A. Thiele, Ana Belen Cueva Sola, Janel Dempsey, Briana R. Schrage, Megan Sibley, Megan E. Simms, Alexander S. Ivanov, Tamalika Ash, Marilu Perez Garcia |
| Abstract Scope |
Modern technologies, including consumer electronics, clean energy, automobiles, and defense, rely largely on the use of rare earth elements. Specifically, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Y are used in permanent magnets, batteries, and phosphors, driving this technology development.
The second most common mineral of REEs is monazite, composed of REE phosphates. It is usually treated via alkali cracking by hot, concentrated NaOH, converting phosphates into insoluble REE hydroxides. Hydroxides are then acid leached to dissolve REE present. Finally, REEs are separated via solvent extraction. However, the current approach is inefficient, energy demanding, environmentally taxing, and expensive.
Thus, precisely synthesized lixiviants were developed for the thermodynamical discrimination between large, light REEs and small, heavy REEs. Several chelators were proposed and tested for selective leaching. The LREEs are leached into the aqueous solution while HREEs remain in the solid phase, allowing for a selective, efficient enrichment and separation. |