How to produce greener lithium, for greener batteries?

Used in most electricity storage batteries, lithium is sometimes singled out for its ecological footprint. It is mined in two types of deposits: brines[1] pumped from underground aquifers, mainly in South America, or spodumene ores[2] mined in open pits. American researchers have compared the environmental impact of lithium extracted by these two methods and the differences are significant.

Whether for the equipment of electric vehicles where the stationary electricity storagethe different variants of lithium ion batteries have become one of the essential links in the energy transition. the lithium is a lightweight metal that only makes up about 2% of a battery’s weight.

Contrary to a (false) rumor, it is relatively abundant on earth. Like sodium, its cousin from the alkaline family (which is one of the components of kitchen salt), lithium is found in ocean water at a rate of 18 mg/l. Even without taking this resource into account, exploitable world reserves are today estimated at 80 million tonnes. At the rate of its current consumption, it will last several hundred years!

For economic reasons it is mainly extracted in two types of deposits:

  • the “brines”[1] which are found in underground aquifers, under the “salars», that is to say the salt deserts present mainly in South America (Bolivia, Argentina and Chile)
  • certain lithium-rich minerals such as “spodumene”[2], mined almost everywhere on the planet, including in Europe, but they are mainly mined in Australia, in open pit quarries, where their lithium concentration is higher. Today, 54% of the lithium used in the world comes from this country.

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Life cycle analysis “

Scientists from theArgonne National Laboratory (the Department of Energy in the United States) compared the environmental footprint of lithium extracted from salars with that from Australian ores. Their study demonstrates that the energy and water consumption as well as the greenhouse gas and sulfur dioxide emissions associated with the production of the lithium incorporated in the batteries, can vary considerably according to its geographical origin as well as the methods used.

The American researchers thus analyzed the life cycle of the lithium extracted from the brines pumped under the Salar d’Atacama, the largest deposit in Chile and one of the largest on the planet. Lithium salts are obtained there by evaporation of water using a method similar to the production of cooking salt in “salt marshes”. The lithium carbonate or hydroxide is then purified by a chemical process and shipped to the factories that manufacture the materials for our batteries.
This production method was confronted with that which makes it possible to obtain lithium from spodumene ores extracted in Australian quarries. The research findings reveal significant discrepancies in ecological impact.

A lithium quarry in Australia

In summary :

  • greenhouse gas emissions are 9 to 20% lower during the process of manufacturing lithium for batteries from the Atacama salt flats than during the process using ore from Australian deposits;
  • consumption of fresh water is lower during the production process for lithium extracted from brines than that required to extract this metal from Australian quarries.

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Useful lessons for European projects

According to Jarod Kelly, the lead author of the study, these differences are largely explained by the type of energy used: the sun to concentrate the Chilean lithium, whereas the production of lithium salts in Australia mainly uses fossil fuels: fuel oil for machinery and coal for refining. But if the manufacture of lithium from spodumene ore used renewable energy, it is certain that the gap between carbon emissions would be reduced.

These lessons should be taken into account in European lithium production projects. As we explained in previous articles, these projects are indeed flourishing, particularly in France and especially in Germany, where a company is already selling the lithium contained in the enormous deposit in the Rhine Valley.

According to geologists, underground hot water tables located in an area 300 kilometers long and 40 kilometers wide between the Vosges and the Black Forest (called the Rhine ditch), could contain enough lithium to manufacture the batteries of 400 million electric vehicles. A prospect that would greatly help European industry to free itself from Asian battery manufacturers.

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[1] A “brine” is water with a high concentration of salts and other dissolved solid elements. The brines found in underground aquifers under the “salars” of South America are loaded with lithium.

[2] Spodumene is a silicate mineral (LiAlSi2O6) that contains lithium

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