Rare Earths Elements
Rare Earth Elements (REEs) are a group of 17 chemically similar metallic elements that are essential in many modern technologies. They include:
-
The 15 lanthanides on the periodic table (Lanthanum to Lutetium)
-
Scandium and Yttrium, which share similar properties and often occur in the same mineral deposits
Despite their name, most REEs are not rare in terms of crustal abundance, but they are rarely found in economically viable concentrations.
Light vs. Heavy Rare Earth Elements
REEs are generally split into two categories based on their atomic number and geochemical behavior:
|
Feature |
Light REEs (LREEs) |
Heavy REEs (HREEs) |
|
Elements Included |
La, Ce, Pr, Nd, Pm, Sm |
Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu + Y |
|
Abundance |
More common in Earth’s crust |
Less abundant and harder to extract |
|
Typical Minerals |
Bastnäsite, Monazite |
Xenotime, Ion-adsorption clays |
|
Economic Value |
Generally lower |
Generally higher (e.g., Tb, Dy, Lu) |
|
Applications |
Polishing powders, catalysts, magnets |
High-performance magnets, phosphors, lasers, medical tech |
|
Weathering Behavior |
More mobile during weathering |
More likely to remain in residual clays |