The rare earth elements (REE) have been identified by the European Commission as among the
most critical raw materials, due a combination of their economic importance and supply risks.
The supply risk is not the result of
a shortage of REE resources in the Earth’s crust, but is related
to a concentration of production in China. A number of supply chain issues can be recognized,
including: economic challenges that currently make it very difficult to open a REE mine outside
China; complex ore mineralogy and textures, which mean that a specific beneficiation flowsheet
must be developed for each REE deposit; the limited number of facilities for REE extraction and
separation outside China; and potential environmental problems such as the common association
of the REE with U and Th
