Infotech

Strategic market, ecological challenge… Understanding rare earths in 5 questions


Posted on Jul 2, 2021 at 11:30 AMUpdated on Jul 2, 2021, 11:46 AM

Almost unknown until the 1970s, rare earths are today the new “black gold”. From electric cars to smartphones, including wind turbines, these metals are now used in the manufacturing process of many high-tech products.

Like oil, this coveted resource is at the center of geopolitical issues, with China concentrating the majority of its production. A production, moreover, far from being environmentally neutral.

1. What are rare earths?

Rare earths are “a category of metals which is also called lanthanides”, explains Michel Latroche, research director at the CNRS at the Institute of Chemistry and Materials of Paris Est. “In the periodic table of the elements, this corresponds to the whole series starting from lanthanum. We also associate two others: scandium and yttrium. Which gives 17 metals in total ”.

Rare earths are a category of 17 metals, here framed in red.Wikipedia

2. Why are they sought after?

Since their discovery, which took place between the end of the 18th century and the first half of the 20th century, rare earths “were rather laboratory curiosities,” says Michel Latroche.

It was from the 1970s that their exceptional physical properties were exploited, in particular their powerful magnetic power. “They have completely revolutionized the world of magnets,” emphasizes Michel Latroche. This makes them elements in high demand in many electronic devices: speakers, medical imaging devices or even computer hard drives.

“In wind turbines, we also find several hundred kilos of rare earths” in the form of permanent magnets, adds the researcher. These same magnets (made of a neodymium-iron-boron alloy) are used to optimize the performance of electric vehicle motors.

Rare earths exhibit properties, in particular magnetic and optical, used for multiple applications.

Rare earths exhibit properties, in particular magnetic and optical, used for multiple applications.BRGM

Also in electric cars, another property of rare earths is used to design batteries. “NiMH batteries, for ‘nickel-metal-hydride’ are made up of several kilos of rare earths, unlike lithium-ion batteries,” explains Michel Latroche.

Rare earths are also used for automotive pollution control. It is found, alongside other metals, in the catalytic converters of cars. “There is only the cerium which can perform this role”, specifies the scientist. During the cracking of crude oil, rare earths also intervene in the form of a catalyst.

Refined rare earths, clockwise from top to middle: praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.

Refined rare earths, clockwise from top to middle: praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.Peggy Greb / ​​AP / SIPA

“Another aspect of rare earths makes it possible to have lasers for which we can very finely adjust the emission wavelengths, and therefore the desired color,” explains Michel Latroche. It is for this ability to create beautiful shades that we also find these metals in smartphone screens and televisions.

“Other applications are possible in ophthalmology, cutting, medical radiography, laser shows, etc.”, explains the scientist. In the military sector, rare earths are also valued for improving missile guidance systems or sonar detection capabilities. Finally, rare earths are used in the form of glass polishing powder, or to capture neutrons in nuclear cycles, lists the researcher.

3. Where are they found?

Unlike rare metals such as platinum or iridium, rare earths “are not that rare”, explains Michel Latroche. “It’s as abundant in the earth’s crust as nickel or cobalt.” In 2017, reserves were estimated at 120 million tonnes, all rare earth oxides combined.

On the other hand, the deposits large enough to be economically exploitable, relatively few in number, are scattered around the planet. “About half of the reserves are in China, which has a clear advantage in terms of resources,” notes the researcher.

China is also the world’s largest producer, for geological reasons, but above all geopolitics. “The extraction of rare earths is an expensive and polluting process. Until the 1990s, the United States had almost a monopoly on production, then they left this market to China, ”he analyzes. “Beijing largely subsidizes this industry, so no one can compete with them today.”

4. Why is this market so strategic?

In twenty years, the global consumption of rare earths has more than doubled, according to the Bureau of Geological and Mining Research (BRGM). In a world increasingly focused on digital and low-carbon, there is no doubt that this trend should continue in the coming years.

In this strategic market, concentrated in the hands of a single country, prices can quickly soar. This is what happened in 2010, when China implemented very restrictive export controls in the form of permits, taxes or quotas, which severely limited the supply for consumption. foreign industrial. After a complaint from the EU, the United States and Japan, the WTO forced the country to end this policy around 2015.

The psychological shock of this crisis has pushed several countries to open (or reopen) extraction sites on their territory to no longer depend on China. This is the case of the United States, which recently relaunched their production at the important Mountain Pass deposit in California, which was shut down in the early 2000s. Australia did the same. with the Mount Weld mine.

Despite everything, the Middle Kingdom keeps the first place in terms of extraction and especially in terms of processing thanks to an expanded industrial fabric throughout the production chain and very high profitability, notes the BRGM. This regularly gives rise to new commercial arm wrestling between Beijing and Washington.

5. What is the impact of the exploitation of rare earths on the environment?

The process of extracting and refining rare earths is extremely toxic and has direct implications for human health and the environment. “You have to extract the ore, process it and separate the rare earth metals. For this, we use large quantities of solvents, some of which are toxic, ”recalls Michel Latroche.

“Either you are virtuous and you treat it until they become harmless, or you are less virtuous and you reject them in nature…”, he sums up. Another problem: the deposits very often contain radioactive elements.

“Traditionally lax” on the environmental level, China has decided to overhaul its standards and opened up the hunt for illegal mining operations, “under the pressure of public opinion” and “in the face of this crisis that the country cannot ignore more, ”underlines an Ifri report from 2019. The production of one ton of rare earths in Baotou, Inner Mongolia, simultaneously produces 75,000 liters of acidic wastewater and one ton of radioactive residues.

“For some rare earths, research is underway to find substitutes to replace them. There is also the possibility of recycling it. The Japanese do it with all their NiMH batteries from their Toyota or Honda, ”says Michel Latroche. But, for the researcher, we must not kid ourselves, “as long as there are cheap rare earths, no one will take care of the substitutes!” “

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