High-throughput screening for discovery of benchtop separations systems for selected rare earth elements

Area of Science:

• Materials Science
• Chemical Engineering
• Sustainable Technology

Background:

• Rare earth (RE) elements are vital for sustainable energy technologies, but supply chain issues necessitate improved recycling methods.
• End-of-life electronics represent a significant, yet largely untapped, source of valuable RE elements.
• Efficient separation techniques are key to economically recovering REs from complex waste streams.

Purpose of the Study:

• To synthesize and characterize a novel ligand, H31·TFA, and its rare earth complexes for separation applications.
• To develop and implement a high-throughput experimentation (HTE) screen for optimizing RE separation conditions.
• To demonstrate the lab-scale separation of critical rare earth element mixtures using the developed HTE-guided method.

Main Methods:

• Synthesis and characterization of tris[(1-hydroxy-2-oxo-1,2-dihydropyridine-3-carboxamido)ethyl]amine (H31·TFA) ligand and its lanthanide complexes.
• Development of a high-throughput experimentation (HTE) platform to screen precipitation conditions (pH and ligand equivalents).
• Lab-scale validation of HTE-predicted optimal conditions for separating neodymium/dysprosium and lanthanum/neodymium mixtures.

Main Results:

• The HTE screen effectively quantified the precipitation of H31·RE complexes across varying pH and ligand concentrations.
• Optimal conditions identified by HTE enabled efficient separation of RE mixtures.
• High separation factors were achieved: SFNd/Dy = 213 ± 34 and SFLa/Nd = 16.2 ± 0.2 in acidic aqueous media.

Conclusions:

• The novel H31 ligand and HTE approach provide a rapid and efficient platform for rare earth element separation and recycling.
• This method minimizes material consumption and accelerates the optimization process for RE recovery from waste.
• The successful separation of Nd/Dy and La/Nd mixtures demonstrates the potential for industrial application in sustainable RE sourcing.