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).