Selective Recovery of Critical Minerals from Simulated Electronic Wastes Via Reaction-Diffusion Coupling

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Critical materials are essential for modern technologies but face supply chain challenges and environmental concerns.
• Efficient and sustainable separation methods are urgently needed for resource recovery from electronic waste.

Purpose of the Study:

• To develop an atom- and energy-efficient chemical separation technique using reaction-diffusion coupling.
• To separate iron, neodymium, and dysprosium ions from model permanent magnet feedstocks.

Main Methods:

• Utilized reaction-diffusion coupling by bringing feedstock solutions into contact with a hydrogel loaded with potassium hydroxide and/or dibutyl phosphate.
• Employed a series of experiments and simulations to determine ion diffusivities and precipitation rates.
• Established a numerical model to predict product distribution.

Main Results:

• Achieved precipitation of up to 40 mM iron from the feedstock.
• Observed enrichment of 73% dysprosium.
• Extracted over 95% neodymium product.
• Determined key kinetic parameters (diffusivities and precipitation rates) for neodymium and dysprosium.

Conclusions:

• Reaction-diffusion coupling is a validated, effective, and versatile approach for critical materials separation.
• This method offers a sustainable alternative, avoiding the need for ligands, membranes, resins, or other specialty chemicals.
• The study demonstrates a proof-of-concept for recovering valuable materials from electronic waste.