Rare Earth Metals

By: Lakshya Mahajan

Introduction

What do catalysts, smartphones, digital cameras, glass, and flat screens have in common? This is a weird grouping, but if you take a deeper dive, you will see something else: Rare Earth Metals.

Shown above: most common uses of rare earth metals in the US (2020)

What are rare earth metals?

Rare earth, itself, is quite a misnomer. They were discovered in the 18th century, at which point they were thought to be quite scarce. Valuable metals like Neodymium, dysprosium, terbium, gadolinium, lanthanum, and praseodymium are available in relatively abundant quantities around the planet. They have high electrical conductivity properties and are generally divided into light rare earth metals and heavy rare earth metals. Rare earth metals consist of scandium and yttrium on the third column of the periodic table and the lanthanides period.

Shown above: rare earth metals (boxed in red) on a simplified periodic table

How abundant are Rare Earth Metals?

Most of the rare earth metals on Earth’s crust are only in the single and double digits in terms of ppm (Parts Per Million). For example, ytterbium (Yb) has a presence of 2.0 ppm. Here are the abundances of a few:

No. Atomic Number on Periodic Table Name Abundance in ppm

1 57 Lanthanum 30

2 58 Cerium 60

3 59 Praseodymium 6.7

4 60 Neodymium 27

5 61 Promethium 10-18

How are rare earth metals obtained and what are their impacts?

Rare Earth Metals are primarily obtained by separating from minerals and ores that contain uranium and thorium. This process produces a lot of waste, called TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials) wastes. According to the United States Environmental Protection Agency, TENORM is defined as “Naturally occurring radioactive materials that have been concentrated or exposed to the accessible environment as a result of human activities such as manufacturing, mineral extraction, or water processing”. Obtaining rare earth metals is a long and arduous process, which involves producing harmful byproducts which can impact the environment and human health negatively.

Where are rare earth metals found?

While rare earth ore deposits are found all over the world, major deposits are found in Australia, China, Russia, and the United States. Smaller ones are found in Canada, India, and South Africa. Promising reserves have also been found in Greenland. Chinese mining operations accounted for about 80% of the rare earth metals mined globally in 2017, mostly originating from bastnasite deposits in Bayan Obo - a site in Inner Mongolia.

What are the economics behind rare earth metal mining?

The demand for rare earth metals has been fluctuating over the decades. Following a rapid increase in demand in the 1980s, the demand somewhat plunged after the collapse of the USSR (in the 1991-1993 era). However, there were significant price hikes in the years 2009-2011, followed by a sharp decline in 2012. Here are the prices of a few rare earth metals (condensed from Environmental Defects And Economic Impact on Global Market of Rare Earth Metals):

Rare Earth Metal 2009 (in USD/kg) 2010 (in USD/kg) 2011 (in USD/kg) 2012 (in USD/kg)

Ce $4.5 $61 $158 $42.5

La $6.25 $60 $151.5 $36

Pr $14 $86.5 $248.5 $175

Nd $14 $87 $318 $154

Dy $100 $295 $2510 $1500

Looking at the prices from 2009-2012 shows how ever-changing the rare earth metal market is.

Conclusion

Rare earth metals have had impacts on our lives in countless ways. From daily technology to defense operations, these metals have shaped our modern world significantly and continue to shape them today. Looking at the economics and mining techniques behind it give a better insight as to why rare earth metals are important, and what we need to change in order to use it for advances more efficiently and effectively.

Citations:

● Pecharsky, Vitalij K. , Gschneidner, Karl A. and Jr., . "rare-earth element". Encyclopedia Britannica, 17 Jan. 2019, https://www.britannica.com/science/rare-earth-element. Accessed 1 December 2021. ● United States Environmental Protection Agency. “TENORM: Rare Earths Mining Wastes.”, https://www.epa.gov/radiation/tenorm-rare-earths-mining-wastes. Accessed 01 December 2021. ● Charalampides, G.; Vatalis, K.; Karayannis, V.; Baklavaridis, A. Environmental Defects and Economic Impact on Global Market of Rare Earth Metals. IOP Conf. Ser. Mater. Sci. Eng. 2016, 161, 012069.