Rising fossil fuel costs and climate change concerns have produced a global emphasis on renewable energy production and sources. Indium is a mineral critically important in the implementation of large-scale photovoltaic systems. Although there are substitutes for indium in many applications, such substitution typically comes at the cost of product characteristics and production efficiency.
Because indium is recovered as a byproduct of zinc production, the supply of primary indium is determined by the supply of zinc, regardless of the market demand for indium. Additionally, a large portion of the indium contained in zinc ores and concentrates is not recovered, as most zinc smelters are not equipped to extract indium. Increased manufacturing efficiency and recycling, especially in Japan, maintain a balance between global indium demand and supply, but indium was not recovered from ores in the United States in 2018 and there is no U.S. government stockpile of this essential commodity. Furthermore, China recovers, from domestic sources, approximately 55% of the world’s refined indium.
With few relevant substitutes, by-product limitations, and primary production occurring in China, it cannot be disputed that trade wars and geopolitical tensions with China could limit the ability of the U.S. to secure necessary indium resources in the future.
Beyond the basics above, what else should we know about indium? Check out the 20 interesting facts below!
- Indium was discovered in 1863 by German chemists Ferdinand Reich and H.T. Richter during a spectrographic analysis of sphalerite ore samples. They named the element indium after the distinctive indigo-blue line in its emission spectrum. Indium remained only a scientific curiosity for years following its discovery and little was known about its occurrence.
- U.S. production of indium began in 1926.
- In 1933, small amounts of indium were added to certain gold dental alloys.
- Research with indium began until 1934 when the Indium Corporation of America identified the first practical applications for indium.
- In 1936, the U.S. Bureau of Mines (USBM) began to track indium as a metal commodity.
- It was not until World War II that indium was used in its first large-scale application – as a coating for bearings in high-performance aircraft engines.
- In 1952, indium use in semiconductor devices began.
- In the middle and late 1980s, InP (indium phosphide) semiconductors and ITO (indium-tin-oxide) thin films for liquid crystal displays (LCDs) were developed, creating new applications for indium.
- The Defense Logistics Agency included indium in the list of materials to be added to the National Defense Stockpile (NDS) in 1989.
- By 1992, thin-film application had become the largest end use of indium.
- In 1995, a tight indium supply situation combined with strong demand led to the implementation of a more efficient recycling process.
- From 2014 to 2017, the United States imported indium from: China, 27%; Canada, 22%; Republic of Korea, 11%; Taiwan, 10%; and other, 30%.
- 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 indium. 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).
- The properties of indium that make it attractive in industrial applications include low-temperature malleability and ductility, low melting point, self-attraction, electrical conductance with light-transparency, and infrared light reflectance.
- Indium, a chalcophile element, is a malleable, silvery-white metal of high-volatility.
- Indium is produced mainly from residues generated during zinc ore processing.
- Some of the major hosts for indium mineralization include: Vein stockwork tin and tungsten deposits, as well as porphyry tin deposits; Volcanic-hosted massive sulfide (VMS) deposits; Sediment-hosted exhalative massive sulfide (SHMS) deposits; Polymetallic vein-type deposits; Epithermal deposits; Active magmatic systems; Porphyry copper deposits; and Skarn deposits.
- Indium has an average crustal abundance of about 49 ppb and is the 61st most abundant element.
- Indium’s hardness is 1.2 on the Mohs scale, its specific gravity at 20° C is 6.25, and it melts at 156.6° C.
- Indium is important in many-cutting edge tech applications, including: transparent conductive coating to glass substrates (such as flat panel displays), semiconductors, light-emitting diodes (LEDs), laser diodes, alkaline batteries, cryogenics, ultra-high vacuum applications. alloys, solders, nuclear control rods, and a variety of electrical components.
Thanks for reading!
Lightning Network tipping jar – any support and/or constructive criticism always appreciated.