When reporting on REE, it is common to use broad subdivisions into Light Rare Earth Elements (LREE), Heavy Rare Earth Elements (HREE) and, occasionally, Medium Rare Earth Elements (MREE).
*Note – Hexagon does not include promethium (Atomic Number 61) in its tabulation as this is an unstable radioactive decay product.
Rare earths are not particularly rare in the earth’s crust. However, they are referred to as ‘rare’ because it is not common for them to occur in economic concentrations and this geochemical aspect, based on their close-positioning on the Periodic Table, is important in the challenges of downstream processing referred to below, namely how to separate elements with such similar chemical and physical properties.
REEs have unique catalytic, metallurgical, nuclear, electrical, magnetic and luminescent properties.
What are REEs used for
REE are utilised in many domestic, medical, industrial and strategic applications because of their unique and often non-substitutable physio-chemical properties.
Hexagon is interested in the utilisation of certain REEs in magnets and super magnets – which it regards as a major growth segment, but REEs are also widely used in metal alloys, electronic and computing equipment, batteries, catalytic converters, petroleum refining, medical imaging, colouring agents in glass and ceramics, phosphors, lasers and special glass.