Rare earths separation from fluorescent lamp wastes using ionic liquids as extractant agents

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Growing demand for rare earth elements (REEs) in advanced technologies necessitates sustainable sourcing.
• End-of-life products, particularly fluorescent lamp waste containing yttrium and europium, offer a viable secondary source for REEs.
• Red phosphors (Y2O3:Eu3+ - YOX) from fluorescent lamps are rich in valuable REEs, making them a key target for recovery.

Purpose of the Study:

• To evaluate the potential for recovering REEs from fluorescent lamp waste, specifically red phosphors.
• To investigate the efficiency of REE separation using novel ionic liquid extractants in chloride media.
• To achieve high-purity separation of yttrium, europium, and cerium.

Main Methods:

• Soft leaching of red phosphors followed by precipitation and calcination to obtain REEs in oxide form.
• Solvent extraction using Cyanex 572, D2EHPA, and their corresponding ionic liquids (Primene 81R·Cyanex 572 IL and Primene 81R·D2EHPA IL) in chloride media.
• A four-stage cross-flow solvent extraction process was employed for individual REE recovery.

Main Results:

• Yttrium, europium, and cerium were individually recovered with high purities (≥99.9%).
• The ionic liquids Primene 81R·D2EHPA IL and Primene 81R·Cyanex 572 IL demonstrated high efficiency in separating REEs.
• Yttrium and europium were successfully stripped from the organic phase using 4 mol/L HCl.

Conclusions:

• Fluorescent lamp waste is a valuable resource for recovering high-purity rare earth elements.
• Novel ionic liquids show significant promise for efficient REE separation in hydrometallurgical processes.
• This method provides a sustainable pathway for REE supply, crucial for technological advancements.