London (AFP)

Essential for the batteries of electric vehicles such as smartphones screens and wind turbines, rare earths are the object of much covetousness worldwide.

These natural elements have become essential to many advanced industries, but why are rare earths so essential? And what role do they play in the geopolitical arena, at a time when China and the United States are at loggerheads on trade?

- What are rare earths? -

Rare earths contain 17 metals not particularly hard to find, some of them being as abundant in the earth's crust as lead or copper. Their "scarcity" comes from the fact that it is unusual to find deposits of commercial utility: these metals are often present only in small quantities within ores from which it is sometimes difficult to extract them.

The US Geophysical Institute, the USGS, for example, regularly surveys American soils in search of a mineable deposit in a profitable way and without damaging the environment. But in the United States, "rare earth ores are mixed in the ground with other complex materials, making it harder to treat them," says the USGS to explain its difficulties in finding interesting veins.

- What are they for ? -

Rare earths have a particular atomic structure that is responsible for many unique physical properties.

For example, europium, which has a red luminescence, is used in television screens. Neodymium, naturally magnetic, is used to make powerful mini-magnets. Lanthanum, which gave its name to the lanthanide family, is used in rechargeable batteries that are used in many electronics and hybrid cars.

According to a report published by the British Geological Survey (BGS), a UK institute of geological studies, rare earths "are the group of elements used in the most consumer products in the world".

Still according to the BGS, rare earths also play "a vital role in protecting the environment, improving energy efficiency and enabling many digital technologies to exist".

- Who holds them? -

According to the USGS, China has the largest deposits of rare earths, with 44 million tons of reserves. Vietnam and Brazil each have 22 million tonnes.

China benefits from two additional assets. Its ores are buried in clay deposits, an "unusual" and favorable configuration, "since it is easier to extract," according to the American Institute. Chinese environmental standards are also less stringent, says the USGS.

On the other hand, difficulties with the American deposits forced the closure of the only American mine in Mountain Pass, California, twice.

"The production at Mountain Pass has resumed in the first quarter of 2018," note the commodity specialists of the Cyclope report, who add, however, that "a large part (of the production) was destined for export to China".

"There is no refinery outside of China," said Mountain Pass Operator James Litinsky in an interview with CNBC, although he believes the mine will be independent of Beijing. refining from 2020.

- Why are they strategic? -

This lack of processing sites outside China, as well as the country's production capacity, make Beijing the main player in the rare earths market.

The importance of China in the supply chain of these metals is enough to give cold sweats in the United States, whose high-tech companies, both civilian and military, rely heavily on rare earths. Especially since the trade conflict between the two countries gives no sign of appeasement.

These fears crystallized at the end of May, when Chinese President Xi Jinping paid a visit to a rare earth processing plant in the middle of a trade war with Washington, threatening China's blocking of rare earth exports. refined.

This is a tactic that China has already put into practice in the past, especially in 2010, when Beijing abruptly halted its rare earth exports to Japan in retaliation for a territorial dispute.

© 2019 AFP