- While there is more than enough lithium in brines, pegmatites, and sediments to meet future demand, how that lithium will be extracted and what environmental impacts will result are among the process mineralogy questions yet to be fully answered.
- As this case study shows, extracting lithium from recently developed, lower grade, and less pure Cauchari-Olaroz brines carries higher operating costs and higher carbon emissions compared to lithium from legacy Atacama brines due to the heavier use of chemicals in pond processes.
- As lithium demand forces the battery industry to explore lower grade and higher impurity resources, life cycle assessments should be used to identify environmental impact hotspots, and new technology developed to ensure that the environmental costs of transitioning the world’s vehicle fleet to EVs do not outweigh the benefits.
Is there enough lithium on Earth to make enough batteries for everyone to drive an electric vehicle? EVs powered by lithium-ion batteries are the leading technology for the decarbonization of ground transport, so we should hope so. This question has been asked in dozens of ways over the last few years as the battery proves out its energy storage capabilities at scale. As we climb the sigmoid of EV adoption, the battery’s scaled up bill-of-materials becomes significant for the broader battery industry, given that demand for lithium is expected to increase by 6–7x between now and 2030 from around 300,000 tonnes of lithium carbonate equivalent per year (tonnes LCE/year) in 2020 to 2,000,000 tonnes LCE/year in 2030 .
The simple answer to the question is yes. The Earth’s crust contains many orders of magnitude more lithium atoms than we will ever need to extract, especially as battery recycling rises to satisfy demand for lithium and other battery chemicals in the 2030s. For example, the ocean contains 0.2 mg/kg of lithium (compared to continental resources which contain hundreds to tens of thousands of mg/kg). But the scale is so massive that, if the lithium could be extracted economically, the ocean would be the largest lithium resource on the planet by five orders of magnitude compared to any deposit on land discovered to date. The ocean contains around one trillion tonnes LCE, while the largest continental resources contain around ten million tonnes LCE. We just don’t have a commercial-scale technology which can extract it economically today.
Discrete continental lithium deposits may be smaller in scale than the ocean, but they are numerous. We know where many of them are and we think we know how to find more, so literal availability is not an issue. Instead, we need to ask how we will extract the lithium from these deposits. This field of study is called process mineralogy and it asks these questions:
- How much lithium will we produce?
- From what type of resource?
- In what jurisdictions?
- Using what extraction and processing technologies?
- With what operating costs?
- Incurring what environmental impacts?
- To make what type of lithium chemicals?
Answering these questions simultaneously is the job of lithium resource developers. To do it well, professionals (including geologists, hydrogeologists, mining engineers, environmental engineers, chemical engineers, and mechanical engineers) need to come together to find the optimum points in this multidimensional phase space. With the market growing so quickly, there is not much time to answer these questions well. There is no central planning committee for how the lithium supply chain should grow, and, in fact, there is plenty of debate between reasonable people about how these questions should be answered. The resources developed in the 2020s will be advanced as a messy, global scramble, governed as much by politics and commercial realities as by technical requirements, and will certainly not be the result of some heady global modeling exercise. There is a lot more drama, randomness, and fate involved in mineral project development than wide-eyed engineers might expect!
So how will we extract all that lithium? First, legacy operations producing lithium salts for other industries like grease and ceramics will increase production considerably, in some cases change the types of products they make, reduce the production of legacy co-products, and strive to meet a new list of expectations from new customers in the battery industry, which may include being asked to reduce their environmental impacts. But that only gets us a fraction of the way to where we need to be in order to make all those batteries. New lithium operations will be built by new companies which will answer the process mineralogy questions differently from how they have been addressed historically. Production will expand to new types of resources in new places that were not considered relevant just years ago.
There are three types of lithium natural resources: pegmatite minerals, sedimentary minerals, and brines.
Pegmatites are “hard rock” deposits: igneous rocks formed when magma cools and crystallizes. In pegmatites, lithium is strongly bound in the crystal structure of ore minerals. The first step in lithium production from pegmatites is to mine the rock, crush it, and concentrate the lithium minerals while removing other minerals. In some cases, these other minerals can be used by other industries, displacing mining elsewhere for things like aggregate used in construction. Energy is then required, in the form of heat and chemicals, to extract the lithium from the ore minerals into an aqueous solution. Once extracted as a sulfate, chloride, nitrate, phosphate, hydroxide, or carbonate, it can be converted to chemicals like lithium carbonate, lithium hydroxide monohydrate, or lithium metal which are used to make batteries.
Sedimentary minerals usually take a consistency more like dirt, and can be broken down into small particles more easily than pegmatites. Some but not all sedimentary mineral deposits are clays, and in these types of resources, lithium is bound to a structure much weaker than in pegmatites. When other minerals are slowly dissolved by rainfall or altered chemically over millions of years, lithium can be released, transported, and then redeposited with clays in lakes and rivers. Some sedimentary minerals require less energy to extract lithium from compared to pegmatite ore minerals. However, they usually contain lower lithium concentrations and are found with high concentrations of contaminant salts compared to pegmatite ore minerals, meaning more waste is extracted along with the lithium. At Tesla Battery Day in September 2020, the company claimed that they are working on ways to produce lithium chemicals from these types of minerals in Nevada .
Brines are salty waters with high dissolved solid contents, which typically form when rainwater containing dilute minerals from mountains or water from geothermal hot springs accumulates in porous rocks (aquifers) in closed basins with dry climates. Since there is no path for water to flow out of closed basins, water can only leave the system by evaporation. This is how salar brine deposits are formed close to the surface. In other instances, brines can be found kilometers deep, and these are commonly referred to as oilfield or geothermal brines depending on the legacy products produced from them.
Before 2010, most lithium production from pegmatites came from deposits containing >1.5% lithium oxide (6,900 mg/kg), most lithium production from brines came from resources containing >1,500 mg/kg, and no significant lithium production came from sedimentary minerals. Most lithium from brines was historically produced using evaporative processes, which involve pumping brine to the surface, exposing it to dry air and wind in large engineered ponds, and sometimes adding chemicals to remove impurities which may cause lithium to be lost to waste salt co-precipitation in the ponds, finally yielding a lithium chloride concentrate which can be converted to battery chemicals. An example of pure evaporative processing of brine is at the Salar de Atacama in Chile, which contains over 1,800 mg/kg of lithium. Silver Peak in Nevada has produced lithium from brine containing less than 300 mg/kg since the 1950s using pure evaporative processing. However, that brine has exceptionally low impurity concentrations, recovery is low, and the physical footprint is high.
Only one lithium brine project in South America produces lithium from brines containing <1,000 mg/kg, however that operation uses a unique direct lithium extraction (DLE) technology to extract lithium, instead of pure evaporative processing. DLE technologies use engineered materials to extract lithium or lithium chloride selectively from brines, leaving the water and low-value salts in the brine so that they may be returned to the hydrological basin. A number of new DLE projects are now being developed, since these kinds of technology may allow economic processing of lower lithium grade and less pure brines including oilfield and geothermal brines. Recent commercial activity suggests that battery manufacturers consider DLE to be less environmentally impactful than pure evaporative processing of brines .
For each type of lithium resource, there is a lithium concentration known as the mineralogical barrier, which represents the minimum grade at which lithium chemicals can be produced economically from that type of resource . A decade ago, lower grade pegmatites and brines and all sediments were on the low-grade side of the mineralogical barrier, and could not be developed economically. With demand booming, the mineralogical barrier has moved and will continue to move towards lower lithium concentrations for all three types of lithium resources. The mineralogical barrier can move “left” with process development for new families of resources, such as the development of new and updated DLE technologies unlocking lower grade brine resources.
A diagram of the mineralogical barrier concept can be seen below.
The build-out of the lithium supply chain is well underway, and we already have some preliminary data on how the mineralogical barrier has moved, and how the questions of process mineralogy have been answered anew. Below is a case study of two South American lithium brines: one legacy and one less than ten years in operation, built to satisfy the demand of the battery industry.
Case Study in Battery Era Growth: Chilean vs. Argentine Brines
A decade ago, there were only three large lithium brine operations in South America: SQM and Albemarle’s evaporative operations at the Salar de Atacama, and Livent’s DLE operation at the Salar del Hombre Muerto. Today there is one additional producing operation in Argentina: Orocobre’s evaporative process at the Salar de Olaroz, part of the Cauchari-Olaroz basin.
The differences between the Atacama and Cauchari-Olaroz show how the lithium industry has approached answering the questions of process mineralogy in the expansion to new brines. In other words, as developers expand into lower grade, less pure resources for which demand has newly arisen, what are the consequences for cost, environmental impacts, and other process mineralogy questions?
Comparing the two…
This is just one example of our venture into lower grade, less pure natural resources to feed the battery industry. The most notable difference between the Atacama and Cauchari-Olaroz is the significant use of chemicals in the evaporation ponds, driving up costs and environmental impacts, and in the case of Minera Exar, the burning of methane to evaporate water at the end of the pond system . It may be possible to avoid these costs and impacts by using DLE, which can circumvent the need to remove Mg, SO4, and excess water from the brine during processing. If a particular DLE technology were to use too many chemicals or too much energy though, these savings could be outweighed by additional cost and higher CO2 emissions.
What Does it Mean?
There are radically different lithium projects in development around the world which represent significant leaps into the unknown of process mineralogy. These are leaps that we must take, as the world will consume all of the lithium produced from deposits like those at the Atacama and Cauchari-Olaroz in just a few years from now. Consider that Cauchari-Olaroz will produce lithium on the order of 60,000 tonnes LCE/year, perhaps with the entire basin reaching 100,000 tonnes LCE/year under aggressive future expansion scenarios, while the Atacama will likely never produce more than 250,000 tonnes LCE/year. That means these two major centers of lithium production will satisfy only around 10–15% of the world’s forecasted lithium demand in 2030 even after significant expansion, though they serve around a third of demand today.
To meet the balance of demand, sedimentary clays will be mined and processed with novel sulfate crystallization flowsheets. Lower lithium concentration, higher impurity brines with exotic geochemistries like geothermal and oilfield brines will be developed with new and updated DLE technologies. Many lower grade pegmatites will be developed and a wider range of minerals will be mined, and who knows, maybe someone will even crack the ocean someday. The mineralogical barrier will continue moving “left” into lower grade and alternative resources.
There is no doubt that we will find enough lithium to meet the battery industry’s needs, so the true question is how, and at what costs, both financial and environmental. To ensure that costs and impacts do not balloon as the world develops these more exotic resources, technological innovation in mineral processing is essential. Further, accounting for CO2 emissions and freshwater consumption in new operations will be critical for ensuring that the environmental costs of transitioning the world’s vehicle fleet to EVs powered by lithium-ion batteries do not outweigh the benefits.
It will be essential to carry out life cycle assessments in the development stages of new operations and to link those life cycle assessments to process mineralogy. We have written about only lithium here, but the same goes for graphite, nickel, cobalt, manganese, and other materials used to manufacture advanced batteries, solar photovoltaics, and wind turbines.
As we lay out in this paper, the lower grade and higher impurity profiles of the new types of resources, which are needed to feed the battery industry, will incur higher costs and higher environmental impacts. These costs and impacts could grow significantly larger unless new resource extraction technology is developed and deployed. The battery industry should work with resource developers to help ensure that this happens. A case study is already in the works: Panasonic and Schlumberger are collaborating on a new DLE technology for brines in Nevada .
To guide the world’s future lithium supply chain towards low cost and low environmental impact resource development, stakeholders like the buyers of EVs, buyers of batteries, buyers of lithium chemicals, and investors need to articulate what they want to see from the lithium industry. Understanding the process mineralogy phase space is a great place to start!
Kathryn Goodenough’s research on lithium is funded by the United Kingdom’s Natural Environment Research Council through the LiFT project. Thank you to Minviro for their prospective life cycle assessment modeling and to our friends in the industry who kindly reviewed this article, especially Austin Devaney, Peter Ehren, and the British Geological Survey. Thank you to Battery Bits for publishing this piece.
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 Lithium Americas, 2019. NI 43–101 Technical Report — Updated Feasibility Study and Mineral Reserve Estimation to Support 40,000 TPA Lithium Carbonate Production at the Cauchari-Olaroz Salars, Jujuy Province, Argentina.
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 Minviro, Jade Cove Partners, and Marbex, 2020. The CO2 Impact of the 2020s’ Battery Quality Lithium Hydroxide Supply Chain. URL.
 Mining Magazine, 2021. Schlumberger and Panasonic launch DLE partnership. URL.
Alex is Partner at Minviro, where he helps build environmental impact models of lithium-ion battery supply chain processes. He is also Technology Innovation Advisor at Zelandez, a lithium brinefield services company with operations in Argentina, Bolivia, and Chile. Alex is a co-founder of Lilac Solutions, a Silicon Valley lithium extraction technology company funded by Bill Gates’s Breakthrough Energy Ventures.
Alex has an M.S. from Northwestern University in Chemical Engineering and a B.Eng. from McGill University in Chemical Engineering & Philosophy.
Dr Kathryn Goodenough is a Principal Geologist at the British Geological Survey. She has worked on geology and resources of critical metals for many years, and is currently Principal Investigator for the LiFT project (Lithium for Future Technology).