Rare-Earth Elements Overview
The rare-earth elements consist of 17 metallic elements: the 15 lanthanides, scandium, and yttrium. These elements are crucial for modern technology and are often used in high-performance magnets, lighting, optics, and catalysts.
Characteristics and Applications
- Periodic Table Position: Lanthanides are usually shown separately beneath the main table, while scandium and yttrium lie in Group 3.
- Physical Properties: These elements are often found in low concentrations and are mixed together, making them difficult and expensive to separate.
- Technological Uses:
- Neodymium-iron-boron magnets, common in motors and generators, including electric vehicles and wind turbines.
- Phosphors that emit light in devices like lasers and optical equipment.
- Used in catalysts, glass, ceramics, and other specialized materials.
Magnetic and Optical Behavior
- Magnetism: Rare-earth atoms have electrons in the 4f shell that maintain strong magnetic moments, crucial for creating stable, strong magnets.
- Phosphors: Produce sharp, stable colors due to 4f electrons absorbing energy and emitting light at fixed frequencies.
Mining and Refinement Process
- Location and Extraction: Economically feasible deposits are rare and dispersed in certain minerals like bastnäsite and monazite.
- Environmental Concerns: Mining can disturb uranium or thorium, and requires careful waste management.
- Refinement Challenges:
- Separation of these elements is complex due to similar chemical behavior.
- Refinement involves multiple stages like beneficiation, chemical cracking, leaching, and solvent extraction.
Global Reserves and Production
- Major Reserves: Include China (44 MT), Brazil (21 MT), India (6.9 MT), among others.
- Production Dominance: China accounts for 91% of global refining and 94% of production of sintered rare-earth permanent magnets.
- Future Prospects: Countries are focusing on building refining and manufacturing capabilities to support green technologies.
