Criticality of metals and metalloids.

Title	Criticality of metals and metalloids.
Authors	T E Graedel, E M Harper, N T Nassar, Philip Nuss, Barbara K Reck
Magazine	Proceedings of the National Academy of Sciences of the United Kingdom
Date	04/07/2015
DOI	10.1073/pnas.1500415112
Introduction	The concept of metal criticality arises from actual or foreseen disparities between metal supply and market requirements. This paper assesses the criticality of 62 metals and metalloids within a three-dimensional framework, considering factors such as supply risk, environmental considerations, and susceptibility to supply limitations. Key drivers contributing to elevated criticality scores include concentrated primary production geopolitically, the absence of viable alternatives, and political instability. Findings indicate that challenges for metals crucial to modern electronics, such as gallium and selenium, primarily stem from supply risks. Platinum group metals, gold, and mercury face constraints due to environmental impacts. Steel alloying elements like chromium and niobium, alongside elements for high-temperature alloys such as tungsten and molybdenum, exhibit vulnerability to supply restrictions. The most critical metals are typically those obtained as by-products, applied in small quantities for niche uses, and lacking effective substitutes.
Quote	T E Graedel, E M Harper and N T Nassar et al. Criticality of metals and metalloids. Proceedings of the National Academy of Sciences of the United Kingdom of Great Britain and Northern Ireland. 2015. Vol. 112(14). DOI: 10.1073/pnas.1500415112
Element	Gallium (Ga) , Selenium (Se) , Mercury (Hg) , Chromium (Cr) , Niobium (Nb) , Tungsten (W) , Molybdenum (Mo) , Platinum (Pt)
Materials	Metals and Alloys , Precious Metals , Steel and Iron-Based Alloys , Nickel-Based Alloys
Topics	Environmental and Green Materials , Structural Materials , Computational Materials Science
Industry	Electronics , Steel & Alloy Producers