CRITICAL METALS FOR THE NEW ENERGY FUTURE

The demand for critical metals such as Li, Co, Ni, Ga, Ge, Nb, In, Sb, Ta, Re, Pt, Pd, and REE, have exponentially increased in recent years due to the production of high-technology products, increasingly in the renewable energy field, that contain small amounts of these metals. These critical metals may be classified into three groups based on the source rocks and deposits: 1) metals associated with mafic and ultramafic rocks (Pt, Pd, Cr, V, Ni), 2) metals associated with reduced or alkaline granitic rocks (W, Mo, Ge, Nb, Ta, In, Sb, REE, Bi, Te, U), and 3) metals from other sources or multiple sources (Li, Co, Ga). South Africa is the dominant country that hosts the first group of metals because of the presence of the world largest Bushveld Complex. China dominates production of the second group metals due to the wide distribution of reduced granitic rocks in its south. Lithium is mainly produced from brine in Chile, and cobalt comes from sediment-hosted Cu deposits in Congo and Zambia, as a byproduct. Although the reported reserves and resources of these metals appear to be sufficient for a few decades, it is indispensable to look for new sources of critical metals, in addition to the exploration and exploitation for the conventional sources. A few of the metals (Ga, Ge, In, Sc, Dy, Te, and possibly the HREEs) do appear to have near-term supply issues which will require additional exploration.