Pyrite From Organic-Rich Shales Could Be Potential Source of Lithium Needed for Sustainable Energy

Iron pyrite, also known as 'fool's gold', is a common mineral which resembles its precious counterpart. This substance may be more valuable than experts originally though, as it has been found to be abundant in lithium.

(Photo : Wikimedia Commons/ Алексей Четверухин и Дарья Филатова)

High Demands for Lithium

To meet the technological needs of energy transition, batteries, like those that power electrical vehicles, have become increasingly important. For this reason, lithium has been vital to the future development of green energy since this highly reactive element is a major component of batteries.

At present, lithium-ion batteries are in wide use, and continued research to improve this has been one of the main focus of energy engineering. This type of battery can also store energy produced by renewable sources such as solar and wind.

Technology revolution and development of new renewable energy resources is driving demand for lithium to new heights. Some of the primary ores of lithium include salar brine, pegmatite, and volcanic-associated clay which are mined in select locations such as China, Chile, Bolivia, Australia, and Argentina. Although these sources are well-understood, it would still be desirable to identify more lithium sources which can be safely and economically exploited.

Lithium From Fool's Gold

As a response to this challenge, researchers from West Virginia University explored whether previous industrial operations, like drill cuttings or mine tailings, can serve as a source of additional lithium without generating new waste materials. Their investigations reveal that lithium can be found in an apparently undervalued mineral.

The results of the study were discussed in the paper "Potential lithium enrichment in pyrites from organic-rich shales." It will be presented during the European Geosciences Union (EGU) General Assembly 2024 which will take place from April 14 - 19.

Led by sedimentary geochemist Shailee Bhattacharya, a team of researchers focused on 15 middle-Devonian sedimentary rock samples obtained from the Appalachian basin in the U.S. They found plenty of lithium in pyrite minerals in shale, a type of sedimentary rock made from mud.

Sequential extraction of the samples was carried out to quantify lithium recovery from targeted rock-forming phases, including pyrites, carbonates, iron-manganese oxyhydroxides, and organic matter. The result of the analysis suggests the possibility that some lithium may be sequestered in pyrite in organic-rich shales.

Geologic literature lacked data on the connection between lithium and sulfur-rich pyrite. However, the electrochemical and engineering industries have already begun to consider how lithium-sulfur batteries can replace lithium-ions. As Bhattacharya described, experts are trying to understand how lithium and pyrite can be associated with one another.

As it turns out, organic-rich shale could have potential for higher lithium recovery as a result of the mysterious connection between lithium and pyrite. Meanwhile, whether the observations can be extrapolated beyond samples from the current study site is still not known.

Bhattacharya cautioned that their research is a well-specific study. She believes that this work is promising because it gives clues at the possibility that particular shales can be a source of lithium that does not require new mines. This means that sustainable energy can be generated without using lots of energy sources.