Strategic minerals are a diverse set of elements which are limiting factors in high-demand commodities in the global economy. In particular, these elements are vital to energy, technology, and agricultural industries. These elements, while varied and diverse in their uses, properties, and locations, can be categorized into five main groups: Rare Earth Elements, Fission Elements, Rare Metals, Platinum Group Elements, and Phosphorus.
Rare Earth Elements (REEs):
REEs: (Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)
Rare Earth Elements (REEs) are a distinct group of seventeen elements on the periodic table. REEs include the elements with atomic numbers 21 and 39, plus the lanthanide series. These elements are among the heaviest naturally occurring non-radioactive elements, and are extensively used in energy and manufacturing technologies.
Contrary to their label, REEs are not necessarily "rare"; the shortage of these important elements lies in the lack of concentrated, and therefore economically feasible, deposits. Finding economically viable deposits of REEs requires significant geological surveying. Fortunately, REEs can often be mined together due to similar chemical properties. REEs form crystaline complexes with nonmetal elements. Often, these REEs are interchangeable within the crystal structure without drastically affecting the properties of the crystal (Beauford, 2010). As such, rare earth ore minerals, like monazite (CeLaPrNd)PO(4), can have varying chemical compositions while remaining structurally indistinguishable in nature. Because of these chemical similarities, it makes sense to group the REEs into a single category.
REEs play a critical role in existing and emerging energy, scientific, and military technologies. For example, dysprosium is used for heat-resistant permanent magnet alloys in wind turbines, and tellurium is used in solar panels (Moss, 2011). Compact fluorescent bulbs depend heavily on praseodymium as a phosphor material (Roskill Estimates, 2012). All of these technologies have very recently entered the global spotlight as the developed world continues to invest heavily in green energy technologies.
Fission Elements (FEs)
Fission Elements: (U, Pu, Th)
The fission elements are radioactive elements primarily used to generate nuclear power. Uranium, plutonium, and thorium are the only three naturally occurring elements that can be enriched, and therefore used as fissile fuel for nuclear reactors. Extractable oxide ore deposits of these elements are abundant, however, as the drive for nuclear power expands in the near future, these elements will become more valuable, increasing the need for a stable supply.
Platinum Group Elements (PGEs)
Platinum Group Elements: (Rh, Pd, Pt, Os, Ir)
Platinum group elements (PGEs) are transition metals with chemical properties similar to platinum. These elements are most commonly used as catalysts in industrial processes and as alloy ingredients. PGE demand is not projected to outstrip supply in the near future, however, the majority of PGE production is concentrated in South Africa (USGS, 2012). Due to the political instability of this region, supply of PGEs has the potential for unpredictable disturbances. Furthermore, as with most current refinement methods, processing PGEs is extremely toxic to the environment. As such, global partners are seeking ways to expand the production base for these minerals, while improving the sustainability of the mining and refining procedures.
Rare Metals and Metalloids (RMs)
Rare Metal Elements: (Ga, In, Zr, Nb, Co, Ta)
The Rare Metals (RMs) are a diverse collection of metallic elements used in emerging technologies which are often confused with REEs. The RMs, however, have few over-arching similarities. Unlike PGEs, these elements are not found in proximity to one another on the periodic table. Four of these elements are transition metals belonging to three distinct periodic groups and two periods. Two of these elements are metalloids, meaning that they have certain metallic uses and certain non-metallic uses. Unlike the REEs, these elements have very different chemical properties. For instance, cobalt is the only ferromagnetic element of the group. Despite the diversity of these elements, all are critically important for the development of specific technologies such as industrial alloys. Some RMs can be used as substitutes for certain REEs, while other rare metals have completely unique applications. For example, indium is a critical component of smartphone touchscreens (Moss, 2011) and zirconium is used in metal alloys and welding rod coatings (USGS, 2012). These elements have been categorized together in order to distinguish these critical elements from the PGEs and REEs.
Phosphorus is sufficiently important to warrant separate consideration. Phosphate, the biologically active form of phosphorus, is vital to the functioning of every organism on earth. Phosphorus has the potential to be the limiting factor for life on earth.
Although phosphate is incorporated naturally into the soil from rocks over long periods of time, mining increases the supply of phosphorus for use in fertilizers. These fertilizers are critical for boosting agricultural output to meet the growing demand for food. However, phosphorus mining has led to some environmental issues, such as nutrient runoff.