rareelement

Rare-earth elements (REEs) are a set of 17 elements, consisting of the 15 lanthanides plus scandium and yttrium. They are not truly rare in Earth's crust; several are relatively abundant, but they are geochemically similar and tend to occur dispersedly, which makes them difficult to locate and separate. They are typically mined from minerals such as bastnäsite, monazite, and xenotime.

Chemically, REEs are assigned a common oxidation state of +3; some exceptions like europium and cerium show variable valence. Their similar chemistry leads to complex mineralogy and challenging separation and purification, often requiring multiple solvent-extraction steps.

Occurrences and production: Large reserves exist in China, Australia, the United States, Myanmar, and other countries. Extractive operations involve open-pit mining, crushing, and chemical processing. Purification yields separated oxides or metals. Demand patterns focus on magnets (neodymium and praseodymium), catalysts (cerium and lanthanum), phosphors (europium and terbium), and other specialty uses.

Applications: Nd-Fe-B magnets are used in motors and turbines; REEs serve as catalysts in petroleum refining; phosphors are essential for lighting and displays; they are also used in polishing powders, rechargeable batteries, and various electronics.

Economic and strategic aspects: Despite overall abundance, uneven distribution and processing costs give REEs strategic significance. China has been dominant in refining; diversification and recycling programs are pursued elsewhere to reduce supply risk.

Environmental and social considerations: Mining and processing generate waste and acid effluents, and minerals like monazite can contain thorium; responsible sourcing and remediation are important.