"Fool’s gold" may actually be valuable as an energy source for tech devices

Laptops are banned from checked luggage on flights for a good reason: their lithium-ion batteries, acting as the device’s power source, pose a significant fire risk due to the highly reactive nature of lithium.

This same reactivity makes lithium an excellent choice for batteries, especially those used in electric vehicles and for storing energy from renewable sources like solar and wind. As a crucial element in the transition to green energy, lithium’s demand has surged dramatically.

Finding alternative sources of lithium

While a vast amount of research has already been done to understand traditional sources of lithium, such as pegmatites and volcanic clays, the quest to identify additional, economically viable, and environmentally safe sources is ongoing. 

In this context, researchers from West Virginia University are investigating alternative sources of lithium, specifically looking at whether remnants of past industrial activities, like mine tailings or drill cuttings, could be tapped without creating new waste.

Demand for lithium as a natural resource 

“In order to meet the technological needs of the energy transition, batteries of all scales, particularly those that power electric vehicles, have become increasingly important.

Lithium-ion batteries are in wide use at present, and continued research to improve them has been a focus of energy engineering. This, in turn, has greatly increased the demand for lithium (Li) as a natural resource,” the authors wrote. 

While the primary ores of Li (pegmatite, salar brine, and volcanic-associated clay) are generally well-understood, it would be desirable to identify additional Li sources that could be safely and economically exploited.

Using material from previous industrial operations (e.g., mine tailings or drill cuttings) as a source of additional Li would be attractive as it would generate little or no new waste material.

Connection between lithium and sulfur-rich pyrite

To identify alternative lithium sources, the experts analyzed 15 sedimentary rock samples from the middle-Devonian period found in the Appalachian basin. Surprisingly, these samples showed significant lithium content within pyrite minerals in shale.

This connection between lithium and sulfur-rich pyrite – colloquially known as “fool’s gold” –  opens new avenues for research, particularly as the scientific community explores the potential of lithium-sulfur batteries as alternatives to the current lithium-ion options. 

“I am trying to understand how lithium and pyrite could be associated with one another,” said lead author Shailee Bhattacharya, a doctoral student in sedimentary geochemistry at the IsoBioGeM Lab.

This inquiry into organic-rich shale may reveal a higher potential for lithium recovery due to the unique interaction between lithium and pyrite.

Shale deposits could serve as a source of lithium 

However, Bhattacharya cautions that while the findings are promising, they are specific to the samples studied and further research is needed to determine if these results can be generalized to other regions.

Nonetheless, this research suggests that certain shale deposits could serve as a new source of lithium, potentially eliminating the need for new mining operations. 

“We can talk about sustainable energy without using a lot of energy resources,” Bhattacharya said, highlighting the dual benefits of this approach in reducing environmental impact and enhancing sustainability in lithium sourcing.

“This study suggests the possibility that some Li may be sequestered in pyrite in organic-rich shales. As pyrite is a common mineral in the Appalachian Basin, this has implications for exploiting shale pyrite in the Devonian sequence if the Li proves economically extractable. Drill cuttings from past and current oil and gas operations are a ready material upon which to test the feasibility of this concept,” the authors concluded.

More about lithium sources

Lithium is primarily sourced from two types of deposits: spodumene-rich hard rock formations and lithium-rich brines. 

Hard rock mining

Hard rock lithium mining involves traditional mining techniques to extract spodumene, a lithium-bearing mineral. 

This method is prevalent in countries like Australia, which is one of the largest producers of lithium through hard rock mining. The extracted spodumene is then processed to produce lithium carbonate or lithium hydroxide.

Lithium brine extraction

On the other hand, lithium brine extraction occurs in salt flats where lithium-rich brine waters are pumped to the surface and left to evaporate in ponds, a process that can take several months. 

This method is more cost-effective compared to hard rock mining and is extensively used in South America, especially in Chile and Argentina. These salt flats, often located in arid regions like the Atacama Desert, hold vast reserves of lithium in their underground pools.

Lithium can also be found in geothermal brines, hectorite clay deposits, and oilfield brines, but these sources are less common and currently less commercially viable. 

The WVU research will be presented at the upcoming European Geosciences Union (EGU) General Assembly 2024.

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