There is only one commercial-scale lithium extraction/processing plant in the US. It’s in northern Nevada, where the largest known lithium deposit in the US was created by a volcano millions of years ago. Today it’s known as the McDermitt Caldera, and it’s home to lithium-rich clay deposits.
Turn your gaze to Lancaster, OH, where there are a few lithium battery processing plants and recycling facilities. Some new mining technologies are also cropping up everywhere in the nation. From California’s Salton Sea to the Arkansas heartland, mining organizations are doing their best to get ahead of the curve and stave off environmental issues before they start.
Considering our current and growing demand for energy storage, which could quadruple in a few years, it’s clear we must be as proactive as possible when mining this precious material.
The US Could Become a Major Player in the Global Minerals Market
The exciting news is that the US has a lot of lithium available, and we might become a major supplier as the energy transition moves forward. That’s why a company called Lithium Nevada is currently planning to launch a new lithium extraction site on the McDermitt Caldera.
Also, there are other materials needed for the energy transition found in the US, especially in Minnesota. It will be good news for our (currently) troubled economy if we can create high-paying jobs and export valuable materials.
But with that growth comes significant risks. Mines can be noisy, dangerous, and pollutive. As we move forward, we must mitigate the environmental impacts of lithium mining and processing.
What can we do? Our last piece covered how we can rehabilitate depleted mine sites for environmental conservation, cropping, or grazing. Today, we’ll look at other ways to behave proactively as new lithium sites pop up. Let’s start with a high-level overview of how lithium extraction happens.
How Traditional Lithium Extraction Works
Most commercial lithium sites extract the material from underground brine reservoirs, called salars. The process is straightforward but time-consuming. Salt-rich water — the brine — is pumped into a series of open-air evaporation ponds. Over 16 or 18 months, the water evaporates, and various salts precipitate out, leaving a brine with an ever-increasing lithium concentration.
Lithium Brine
During this process, a slurry of “slaked” hydrated lime, Ca(OH)2, is added to the brine to remove other elements, like magnesium and boron (which have uses in the energy transition.) Finally, once the lithium concentration reaches a certain purity, the brine is pumped to a recovery facility to extract the metal.
From there, the mixture undergoes the following:
- Brine purification to remove contaminants
- Chemical treatment to precipitate out desirable products and byproducts
- Filtration to remove solids
- Treatment with sodium carbonate — soda ash, Na2CO3 — to precipitate out lithium carbonate (Li2CO3)
And finally, we wash and dry the product to complete the process. Now, that processed lithium can be used to make lithium-ion batteries, which are crucial for energy storage in electric vehicles (EVs) and solar arrays.
The environmental challenges of this method include:
- Earth-scarring and a vast footprint
- Diesel fuel use that leads to greenhouse gas (GHG) emissions
- Freshwater pollution
Hard Rock Mining
There are 145 minerals that contain lithium. But, compared to the brining method, hard rock mining is more complicated, expensive, and energy-intensive.
As of 2022, we only use five minerals from hard rock mining:
- Spodumene
- Petalite
- Lepidolite
- Amblygonite
- And eucryptite
Australia currently accounts for much of the world’s spodumene production. There are smaller operations in Brazil, Portugal, Africa, and China. By 2025, we’ll probably see hard rock mining in Finland, Canada, and the US.
The environmental impacts of this method include GHG emissions and earth scarring.
The Future of Seafloor Mining
And finally, there is a potential for lithium extraction from the seafloor. While this technology doesn’t yet exist, it’s in the works, and the outlook is good. It will involve hauling large chunks of seafloor to the surface to undergo hard rock mining.
The environmental impacts of seafloor mining are yet to be studied, but we expect they’ll include biodiversity issues and maritime pollution.
Regardless of the origination of the ore, the process goes like this:
Once the ore is collected, it’s crushed and roasted at 2012°F. It is then cooled, milled and roasted again, this time with sulfuric acid, at 482°F, a process known as acid leaching. During the last step, the hydrogen in the sulfuric acid is replaced with lithium ions to produce lithium sulfate and an insoluble residue.
As in brine-based lithium extraction explained above, lime is added to remove magnesium. Again, soda ash will precipitate lithium carbonate; lime slurry may be used to neutralize excess acid from the acid leaching process. The final product is ready for use in the energy transition.
Now that we understand the processes involved, let’s start thinking about ways to reduce the impact of lithium processing.
How Can We Reduce the Effects of Lithium Extraction & Processing?
For land-based operations, one of the most significant challenges is earth-scarring. In a previous piece, we discussed how mines could be treated, filled, and hopefully re-used for more sustainable and environmentally friendly activities. The next problem is water use and water pollution. We’re happy to report that many advances toward a greener lithium process are happening right here in the US.
Exploring New Mining Technology: Direct Lithium Extraction in Arkansas
The mining sector is making significant advances that could help mitigate land disruption, environmental impact, and water use. Direct lithium extraction is a new method of acquiring lithium that uses very little fresh water.
The first-of-its-kind direct lithium extraction plant now exists near El Dorado, Arkansas. The “LiSTR” process used there selectively extracts lithium ions from tail brine, a byproduct of existing bromine production facilities. When compared to the conventional lithium brine process, the LiSTR process is said to:
- Vastly reduced recovery time
- Be significantly more energy efficient
- And result in a purer product
Another up-and-coming lithium extraction method immerses reusable beads to extract lithium from the salty brines below the surface.
Solving the Extraction Problems at California’s Salton Sea
The Salton Sea was once a scenic tourist attraction in California. This accidental watering hole was created by spillage from a poorly wrought irrigation dam. It created a 400-square-mile lake in the Salton basin in 1905. As an endorheic lake, the Salton Sea doesn’t drain into the ocean. Water either evaporates into the atmosphere or drains down into the earth.
More than a century later, wicked California droughts have dried up much of the water, and the remaining briny liquid is heavy with salts. It’s also toxic. But that brine hosts lots of lithium.
Today, visitors to the Salton Sea see the steam from 11 geothermal power plants. At one of those plants, a San Diego-based company called Energy Source claims to have developed a process that solves the environmental issues of lithium mining. They’ve applied for patents, and we’re excited to hear how that turns out.
The Energy Source Plan
This author is not a chemist by any means. Still, it seems like the process will act much like the copper collecting process we already use, with the application of geothermal electricity from the Salton Sea plant. Per one patent application, “The system and process [include]: 1) an impurity removal circuit; then 2) a continuous counter-current ion exchange (CCIX) circuit for selectively recovering lithium chloride from the brine flow and concentrating it using a CCIX unit; and then 3) a lithium chloride conversion circuit for converting lithium chloride to lithium carbonate or lithium hydroxide product.”
If it works, the outlook for this technology looks good. We already know copper extraction uses a similar technology that relies on an electrical current run through pools of material that allows the copper to collect on cathodes. Check out a previous article to learn more about that process.
But will it be enough? Will a few new methods for extraction and processing solve enough of the potential environmental issues? No one can say for sure, but probably not. We’ll need to look for more ways to temper our need for lithium and develop more effective mining technology.
What Else Can We Do?
Beyond better mining tech, we can address some of the current earth scarring. For example, we should refill and replant mines in the African rainforests for reforestation.
And while this idea sounds unattractive, we could use some depleted mines as landfills. While we hate to think about giant, disgusting pits of trash, we use them and need them. Here in the US, we’re running out of dedicated landfill space. As the population grows, we’ll only create more trash. It has to go somewhere.
Perhaps we can find a way to contain depleted mines for waste storage and use others for massive composting operations. It’s just an idea, but we’ll need to experiment with all kinds of new ideas as the energy transition manifests.
Related Reading & Resources:
Stsystems.com: Lithium Extraction Technology
Greenbiz.com: Lithium mining is Booming – Here’s How to Manage its Impact
Parks.ca.gov: Salton Sea State Recreation Area
Allthatsinteresting.org: The History of Salton Sea
Roadrunnerwm: Landfills: We’re Running Out of Space
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