Rare-Earth Elements

Rare-earth elements are a group of 17 metallic elements in the periodic table, comprising 15 lanthanides, scandium, and yttrium. Despite not being rare in the Earth's crust, they are found in low concentrations and are difficult to separate, making them expensive to process.

Importance and Applications

• They are crucial in the production of high-performance magnets, specialized lighting, optics, and catalysts.
• Neodymium-iron-boron magnets are the world’s most common magnet type involving rare-earth elements and are used in electric vehicles and wind turbines.
• Phosphors, important in emitting light, incorporate europium and terbium, while lasers use neodymium and erbium.

Magnetic Properties

• Rare-earth atoms have 4f electrons that maintain strong magnetic moments.
• These properties result in strong magnetization and stability, essential for efficient motors and generators.

Mining and Environmental Concerns

• Rare-earth ore deposits are usually found in specific rock and soil pockets.
• Open-pit mining is common due to the dispersed nature of these minerals, often requiring careful handling of associated thorium or uranium.

Processing

• The process involves beneficiation to separate valuable mineral grains, chemical cracking with acids or bases, and leaching to dissolve rare-earth atoms into a liquid.
• Solvent extraction is used to separate rare-earth elements due to their similar ionic properties, requiring multiple stages for high purity.
• Final products are usually stored and transported as rare-earth oxides.

Global Production and Reserves

• According to the US Geological Survey, global reserves are over 90 million tonnes of rare-earth-oxide equivalent.
• Major reserves are in China (44 MT), Brazil (21 MT), and India (6.9 MT), among others.
• China dominates separation and refining, accounting for 91% of global production and 94% of sintered rare-earth permanent magnets.
• Japan plans to excavate rare-earth-rich mud from underwater near Minamitori Island by 2026.

Challenges and Strategic Importance

• The arduous refinement process means countries with deposits may still rely on others for pure rare-earth oxides.
• Countries are focusing on building refining and magnet-making capacities due to their importance in green technologies.