The market for cesium is relatively small and world reserves are massive when compared to world demand. Because cesium supply is vast, and most cesium reserves are located in geopolitically stable countries, no supply disruptions are expected by analysts.
However, the United States is completely dependent on cesium imports. In 2018, the U.S. sourced the majority of its pollucite, the principal cesium mineral, from the largest known deposit in North America at Bernic Lake, Manitoba, Canada. Unfortunately, that operation ceased mining at the end of 2015 and has continued to supply cesium products from stocks. Considering that all cesium used by the United States is imported, it cannot be disputed that trade wars and geopolitical tensions could limit the ability of the U.S. to secure necessary cesium resources in the future.
With cesium isotopes used as an atomic resonance frequency standard in atomic clocks, and playing a vital role in aircraft guidance systems, global positioning satellites, and internet and cellular telephone transmissions, a cesium supply crunch cannot be allowed and resources must be monitored closely. For these reasons, the United States has declared cesium to be a Critical Mineral Resource essential for national sovereignty.
Beyond the basics above, what else should we know about cesium? Check out the interesting facts below!
- Cesium is the first element discovered via emission spectroscopy.
- Discovered by Robert Bunsen and Gustav Kirchhoff in 1860, this new element was named “cesium” after the two prominent blue lines of its emission spectrum (from Latin “caesius,” meaning “heavenly blue”).
- In 1881, Carl Sefferberg isolated cesium metal by electrolysis of its salts.
- Cesium found no significant application until it was used in radio vacuum tubes in the 1920s.
- The 1950s began to see the use of cesium in electronics.
- In May 2018, the U.S. Department of the Interior, in coordination with other executive branch agencies, published a list of 35 critical minerals (83 FR 23295), including cesium. This list was developed to serve as an initial focus, pursuant to Executive Order 13817, ‘‘A Federal Strategy to Ensure Secure and Reliable Supplies of Critical Minerals” (82 FR 60835).
- Cesium is very soft and is one of four metals that are liquid at or near room temperature. The other metals liquid at room temperature are mercury, gallium, and francium.
- Cesium is the most electropositive of the five naturally occurring alkali metals.
- Cesium is the most reactive of the alkali metals – the metal ignites spontaneously in the presence of air and reacts explosively in water.
- Cesium is the least abundant of the five naturally occurring alkali metals. Cesium averages approximately 3 parts per million in the Earth’s crust, is 45th in order of abundance of all elements, and is 36th in order of abundance of all metals. Cesium averages approximately 8 parts per billion by weight in our solar system.
- Cesium be mined in only a few places in the world – the world’s largest deposit of pollucite, the principal ore of cesium, is at Bernic Lake, Canada, and accounts for more than two-thirds of world reserves.
- Commercially, most cesium is produced as a byproduct of the production of lithium metal.
- Only one stable isotope of cesium occurs naturally, and that is cesium-133.
- The U.S. military frequency standard, the United States Naval Observatory Time Scale, is based on 48 weighted atomic clocks, including 25 cesium fountain clocks.
- Cesium finds important application in petroleum cracking, high-pressure well drilling (for oil and gas production and exploration), high-temperature solders, x-ray phosphors, energy conversion devices (such as fuel cells and polymer solar cells), infrared detectors, optics, scintillation counters, spectrophotometers and radioscopes, isopycnic centrifugation, insect repellent (in agricultural applications), and as a colorant and oxidizer in the pyrotechnic industry. Cesium-137 is widely used in industrial gauges, in mining and geophysical instruments, and for sterilizing food, sewage, and surgical equipment.