Potential deposits of the rare earth elements and associated critical metals in the circum-Mediterranean regions

The ‘critical metals’ are those metals for wh
ich demand is increasing, typically due to
their use in green and high-tech applicati
ons, and for which there are concerns about
supply risk. Several different methods have
been used to estimate criticality (e.g. EC,
2014; Graedel et al., 2015). Virtually all studi
es place the rare earth elements (REE)
among the most critical of all raw materi
als, due to the concentration of their
production in China. Other crit
ical metals that may be fo
und in association with the
REE include niobium (Nb)
and tantalum (Ta).