Zinc is the 23rd most abundant element in the earth’s crust. Sphalerite, zinc sulfide, is and has been the principal ore mineral in the world. Zinc is necessary to modern living, and, in tonnage produced, stands fourth among all metals in world production – being exceeded only by iron, aluminum, and copper.  

Zinc uses range from metal products to rubber and medicines.  About three-fourths of zinc used is consumed as metal, mainly as a coating to protect iron and steel from corrosion (galvanized metal), as alloying metal to make bronze and brass, as zinc-based die casting alloy, and as rolled zinc. The remaining one-fourth is consumed as zinc compounds mainly by the rubber, chemical, paint, and agricultural industries. 

Why Is Zinc A Critical Raw Material?

Zinc was added to the United States critical minerals list in 2022 primarily due to the massive demand surge from America’s infrastructure and renewable energy buildout. The Biden administration’s $1+ trillion infrastructure investments require enormous quantities of zinc for galvanizing steel used in guardrails, bridges, light poles, and renewable energy infrastructure. This surge in demand comes at a time when global zinc mining operations are already struggling to keep up with existing baseload demand, creating significant supply concerns for this essential industrial metal.

The most significant factor in zinc’s critical designation is the increasing concentration of global production in China, which the US considers a strategic competitor. Over recent decades, China has dramatically expanded its zinc mining and smelting capacity, creating a supply chain vulnerability for the United States. Despite having 14 operating mines and three smelter facilities domestically, the US still relies on imports for 83% of its refined zinc consumption – approximately 710,000 tonnes annually. This high import dependency combined with production concentration in a single country creates exactly the type of supply chain risk that the critical minerals framework was designed to address.

Zinc’s inclusion on the critical minerals list reflects its quantitative risk assessment score of 0.48, which exceeds the 0.40 threshold used by the US Geological Survey to determine criticality. Under the Energy Act of 2020, critical minerals are those with both high supply chain disruption risk and essential functions in the economy or national security. Zinc meets both criteria through its indispensable role in corrosion protection for infrastructure and industrial applications, combined with the geopolitical risks posed by concentrated global production and America’s heavy reliance on imports to meet domestic demand.

20 Interesting Facts About Zinc

1. Zinc is a bluish-white metal with atomic number 30 and sits in Group 12 of the periodic table, making it a transition metal with a completely filled d-orbital (3d¹⁰).
2. At 419.5°C (787.1°F), zinc melts at a relatively low temperature for a metal, but it has an unusually low boiling point of 907°C, making it volatile compared to other common metals.
3. Zinc exhibits only one oxidation state (+2) in virtually all its compounds, unlike many transition metals that show variable oxidation states.
4. When heated in air, zinc burns with a bright bluish-green flame, producing zinc oxide smoke that was historically called “philosopher’s wool” by alchemists.
5. Zinc is the 24th most abundant element in Earth’s crust, comprising about 0.0075% (75 ppm) of the crustal rocks.
6. Zinc undergoes a phenomenon called “zinc pest” – at temperatures below 13°C, it can slowly transform from its normal hexagonal crystal structure to a brittle allotrope, causing metal objects to crumble.
7. Pure zinc exhibits superplasticity at room temperature, meaning it can undergo extensive deformation (over 200% elongation) without breaking when subjected to specific strain conditions.
8. Zinc has unusual acoustic properties – zinc alloys are used to make cymbals because of their unique sound dampening characteristics and tonal qualities.
9. Zinc is the second most abundant trace metal in the human body after iron, with 2-3 grams distributed throughout an adult’s tissues.
10. Over 300 enzymes require zinc for their catalytic activity, including alcohol dehydrogenase, carbonic anhydrase, and zinc finger proteins that regulate gene expression.
11. Zinc ions can act as neurotransmitters in the brain, being stored in synaptic vesicles and released during neuronal activity, particularly in the hippocampus.
12. The human body has no specialized zinc storage system, requiring daily intake – zinc deficiency affects about 2 billion people worldwide and can cause growth retardation and immune dysfunction.
13. Zinc’s standard electrode potential (-0.76 V) makes it an excellent sacrificial anode, protecting iron and steel from corrosion by preferentially oxidizing itself.
14. In the historic Daniell cell (invented 1836), zinc’s reaction with copper sulfate produces 1.1 volts, making it one of the first practical batteries.
15. Zinc-64 can be transmuted into gallium-67 in nuclear reactors, producing a medically important radioisotope used in cancer imaging.
16. When zinc is rolled or bent, it produces a characteristic crackling sound called “tin cry” (despite containing no tin), caused by crystal twinning deformation.
17. Zinc forms over 55 minerals in nature, with sphalerite (ZnS) being the most economically important, often containing valuable trace elements like indium and germanium.
18. In aquatic environments, zinc speciation is pH-dependent – below pH 7, toxic Zn²⁺ dominates, while above pH 8, less bioavailable zinc hydroxide complexes form.
19. Zinc oxide nanoparticles exhibit quantum confinement effects, showing size-dependent photoluminescence that makes them useful in UV lasers and LEDs.
20. Zinc has five stable isotopes (⁶⁴Zn, ⁶⁶Zn, ⁶⁷Zn, ⁶⁸Zn, ⁷⁰Zn), with zinc-64 being used in physics experiments to study neutrinoless double beta decay, a process that could reveal fundamental properties of neutrinos.

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