Rare Earth Elements in Chile: A Critical Review of Primary, Secondary and Marine Resources, Metallurgical Recoverability and Future Supply Chain Opportunities

The economic value of rare earth elements (REE) is concentrated in Nd, Pr, Dy and Tb. The supply chain for these elements is dominated by a single country, China, which accounts for about 60% of mined production, over 90% of refinement, and nearly 95% of permanent magnet manufacturing. This shifts the critical question from geological availability to the capacity to convert resources into products. Chile hosts several domain types for REE: ion-adsorption regoliths, primary mineralization associated with skarn, iron oxide–apatite (IOA) and iron oxide copper–gold (IOCG) systems, pegmatites and placers, and an Exclusive Economic Zone with marine occurrences. The inventory is organized using a five-level evidence scale, compiled through structured searches of indexed databases and institutional repositories under explicit inclusion criteria. Only one record reaches level 1, Penco, with 27.5 Mt Measured and Indicated at 2292 ppm TREO and 62.9 kt contained TREO. Its grade is two to three times higher than that of ion-adsorption deposits abroad, but its tonnage is one to two orders of magnitude lower. Recoveries vary by element, from 19.53% for Nd to 43.23% for Dy, meaning that the REE oxide it contains does not equate to fully recoverable product. Nahuelbuta reaches 2000 ppm exchangeable, Cerro Carmen contributes 19.81 Mt containing 8203 t of rare earth materials and 1811 t of U, and El Buitre contains 6.6 Mt at 337 mg/kg. Reported concentrations span four orders of magnitude, but only two of the five measurement scales include an associated tonnage. Metallurgical recoverability follows the same pattern: saline desorption is mature and retains Th and U in the solid residue, acid leaching of copper residues reaches 64.5% at laboratory scale, the monazite–xenotime and apatite routes are proven but untested on Chilean material, and no domain has demonstrated separation capability. Opportunities lie in by-product recovery from iron and copper operations, modular development of the central-southern corridor, and domestic separation. Converting the available evidence into comparable figures would reshape the national hierarchy more than additional exploration.