American Innovators Needed to Bring Clean Lithium Extraction Home
Authors: Maddie Bundy and Yan Yan
The US is responsible for less than 2% of global lithium production, making the current lithium stock almost entirely imported. Finding and utilizing an extraction technology that can work in the U.S. market is important to not only keep up with demand, but also to take advantage of domestic resources – yet the best method of extraction is still unclear. Through the DOE American-Made Challenges, innovators are working on improving current methods of direct lithium extraction, a key method of separating lithium from brines. For this competition based event, teams are awarded for conceptualizing and prototyping solutions that increase market viability for direct lithium extraction while reducing costs and environmental impacts. If you would like to learn more or chat with someone at ADL about this opportunity, fill out the form to the right!
The electric vehicle industry is growing bigger and bigger. It seems like every car company is coming out with an all-electric version of their most popular cars. One of the biggest roadblocks to producing enough electric vehicles (EVs) for a carbon-free economy is the lack of enough lithium for the projected number of batteries. As global demand increases and climate change programs incentivize EV use, the relevant supply chains need to be expanded.
On top of EV use and expansion, grid-scale energy storage is causing additional demand for lithium. As solar and wind grow, technologies to stabilize energy systems such as batteries become more and more vital. According to the World Bank Group, the production of lithium has to increase by 500% to keep up with energy storage demands.
Mineral demand forecasts based on various climate change goals
Types of Lithium Extraction Technologies
Currently, lithium extraction is dominated by two methods: hard rock mining and evaporating underground brine in shallow ponds. However, new technologies are under development that are less costly and significantly more environmentally friendly. One interesting technology is direct lithium mining from geothermal brines, which looks the most promising when it comes to reducing carbon emissions, land use, and water use.
Hard Rock Mining
Approximately 60% of the world’s lithium production comes from Australia, where the predominant method of extraction is hard rock mining. Pegmatites, a type of igneous rock, are the main source of lithium. These rocks contain a high lithium content mineral called spodumene, which can be processed into either lithium hydroxide or lithium carbonate. The lithium from hard rock mining is also of higher quality and takes less time to collect when compared to other extraction methods. The rock begins being processed by an initial roasting to expand the crystal structure, a carbon-intensive procedure. For every tonne of lithium hydroxide produced, an estimated 15,000 kg of carbon dioxide is emitted, the equivalent of burning 1,688 gallons of gasoline. Out of the three major extraction techniques, this is by far the most carbon intensive.
The other 40% of lithium production mostly comes from South America and China, where evaporation ponds are most popular. Brine is pumped from underground reservoirs to shallow, man-made ponds and left to sit for months or even years until most of the water has evaporated before processing for lithium. These shallow ponds use large amounts of land but are useful when trying to extract other minerals such as potassium or sodium. One huge downside to these evaporation ponds is the amount of water required; this greatly affects not only the environment but also the surrounding communities as these ponds are often found in already dry climates.
Direct Lithium Extraction from Geothermal Brine
The third technology of interest is currently being developed with many companies and research groups putting their efforts into perfecting the process of geothermal lithium extraction. Lithium extraction coupled with geothermal energy production results in the lowest carbon emissions as well as lowest land and water usage. The entire process works as an add-on to geothermal plants, where hot brine is pumped to turbines that generate electricity from the heat of the underground reservoirs. Then, the brine is pumped through a direct lithium extraction (DLE) process and reinjected into the ground.
DLE Process Diagram
Why DLE is Superior
DLE from geothermal brine does not suffer water losses from evaporation, making the process much faster than evaporation ponds. According to a life cycle analysis by Minviro, the cost per tonne of lithium produced is also considerably lower, costing around $3100 per ton instead of the $5800-$6800 cost for hard rock mining and evaporation ponds. Geothermal lithium extraction has the added benefit of being coupled to geothermal power, which is able to drive the lithium refining process. As seen by the figure below, DLE also has lower water and land use, making it a friendlier technology to surrounding communities.
One of the biggest issues with hard rock mines and evaporation ponds is the effect on surrounding communities. One example of current conflict is in Nevada, where Lithium Americas is currently working on a project to develop a large scale hard rock lithium mine. This mine has generated protest among ranchers, environmental groups and Native American tribes due not only to the billions of gallons of water and huge amounts of land that would need to be used, but also due to the use of harsh chemicals to extract lithium from the rock. Fears of toxic runoff contaminating drinking water coupled with fears of not having enough drinking water at all caused the project to be put on hold until more can be understood about the ramifications of these lithium mines. Fearing such project delays and potential settlements, many investors are turning towards the geothermal coupled method, since there are significantly less environmental and societal consequences.
One location looking to explore this specific type of extraction is in California. Since California is spearheading EV initiatives in the United States, the Salton Sea, a shallow lake on the San Andreas fault close to Mexico, is a landmark mining location for lithium. This “lithium valley” is the main location for DLE innovation in the United States and increasing production of lithium is critical to keep up with EV manufacturing.
The lithium reserves in this area alone are more than enough to convert the United States from a net importer to a net exporter, with an estimated lithium carbonate annual production capacity of 600,000 tons.
DLE Challenges and Opportunities for Innovation
Direct lithium extraction from geothermal brines may be promising, but still needs to be improved upon. For example, one main component to DLE is the use of sorbents that are selective of lithium, inexpensive, and avoid fouling from other minerals at high concentrations within the brine. This is a huge concern for the advancement of the technology, as sorbents are the first and main component used to separate the lithium out. After going through the sorbents, the lithium solution is conventionally purified, leaving most room for improvement in the initial separation step.
Additional problems include the corrosivity of the brines, which requires the use of corrosion-resistant coatings. The brines also need to be held at a high temperature to avoid unwanted minerals precipitating out, complicating the lithium separation process. These solids also make reinjection of the brine back into the earth problematic; any built-up solids can plug up injection holes, causing a block in the cyclic system. This makes reliably controlling processing conditions and waste management extremely important. Such problems need to be – and are currently being – addressed to bring DLE into full scale production.
One way innovation is currently being driven is the American Made Geothermal Lithium Extraction Prize. The purpose of this prize is to catalyze new ways to increase market viability for DLE from geothermal brines by addressing any of the problems above, or proposing any idea that improves DLE. The prize is split into three progressive phases that move from concept to design to prototype. The first deadline for the concept phase is September 2nd and the competition runs into Spring 2023. The $4 million cash prize pool will be distributed between winners, so check out this link for details on what to submit and where to turn in applications. ADL Ventures is a power connector for the American Made Network, and we are happy to assist anyone interested as well as answer any questions!