Rare-earth separation

Rare-earth separation isolates individual rare-earth elements from mixtures, despite their closely similar chemical properties. It relies chiefly on small differences in how the elements partition between phases or bind to chemical agents.

Solvent extraction: A liquid–liquid separation method that transfers dissolved substances between immiscible phases using selective chemical agents. Industrial plants exploit slight differences in how rare-earth ions partition between aqueous and organic phases.
Rare-earth element: A member of the lanthanide series, plus scandium and yttrium, with related chemical properties. These are the elements that separation processes isolate from mixed feeds.
Rare-earth mining: The extraction of rare-earth-bearing minerals from the Earth for processing. Mining supplies the mineral concentrates that feed rare-earth separation circuits.
Fractional crystallization: A method that separates substances through repeated crystallization based on differences in solubility. It is a historical alternative to modern extraction, but usually requires many cycles for rare-earth mixtures.
Rare-earth supply chain: The network of mining, processing, manufacturing, and trade that delivers rare-earth materials to users. Separation capacity is a key processing link between mineral production and refined products.
Liquid–liquid equilibrium: The condition in which components distribute between two liquid phases at equilibrium. Partition equilibria determine how much each rare-earth element moves into the extracting phase.
Lanthanide contraction: The gradual decrease in lanthanide atomic and ionic radii as atomic number increases. The contraction creates small size differences that can produce measurable differences in complexation and extraction.
Rare-earth recycling: The recovery of rare-earth elements from discarded products and manufacturing waste. Recycled materials require separation after rare earths are leached into mixed solutions.
Precipitation: The formation of an insoluble solid from a solution through a chemical reaction or change in conditions. Precipitation can recover groups of rare earths, but often lacks the selectivity needed for individual elements.
Critical minerals: Minerals judged essential to economies or security and vulnerable to supply disruption. Rare-earth separation capacity affects access to materials classified as critical.

Linked from 9 pages