Emergent mutual separation strategy for rare-earth elements based on crystallization of coordination compounds

Area of Science:

• Materials Science
• Inorganic Chemistry
• Sustainable Chemistry

Background:

• Rare-earth (RE) elements are crucial in industrial applications due to unique properties.
• Their similar chemical properties make mutual separation challenging, hindering discovery and application.
• Increasing RE product demand raises supply risk concerns, necessitating sustainable recycling strategies.

Purpose of the Study:

• To review novel strategies for RE separation over the past decade.
• To focus on separation methods utilizing the crystallization of coordination compounds.
• To promote efficient RE recycling and support a circular RE economy.

Main Methods:

• Summarizing separation systems based on coordination polymer crystallization with RE ions and organic ligands.
• Describing separation via crystallization of discrete RE complexes with organic ligands.
• Emphasizing ligand structure, separation factors, and crystallization conditions.

Main Results:

• Coordination compound crystallization offers a promising route for selective RE separation.
• This approach facilitates the recovery of RE ions from end-of-life products (urban mines).
• The review highlights advancements in ligand design and crystallization techniques for improved separation.

Conclusions:

• Crystallization of coordination compounds presents a novel and effective strategy for rare-earth element separation.
• This method supports sustainable RE recycling and the development of a circular economy.
• Further research into ligand engineering and process optimization can enhance separation efficiency and reduce environmental impact.