Lilac Solutions, a lithium extraction firm with offices in Oakland, California, was founded and is led by Dave Snydacker.
Pollutes Water Sources
Most lithium miners in 2021 obtained the mineral from hard rocks in regions like Australia and North Carolina. Others dug it up in Chile and other dry areas from the ground’s brine of salt.
The majority of studies link the salinization of freshwater, which the natives depend on for survival, to lithium mining in South America from salt brines. The mining procedure also contaminates nearby water basins because the ore includes hazardous compounds. Therefore, lithium mining puts the local ecosystems at risk of poisoning and other linked health issues.
In general, high levels of water pollution may severely unbalance the regional ecosystems and have a negative impact on the environment.
Increases Carbon Dioxide Emissions
The entire lithium extraction procedure raises atmospheric levels of greenhouse gases like carbon dioxide. In order to remove obstacles, lithium miners clear the places they have chosen for mining of all other living things, including trees.
During photosynthesis, green plants and trees take extra carbon dioxide from the atmosphere. Therefore, lithium miners prevent this process from taking place.
Heavy equipment used by lithium miners also uses a lot of energy and generates a variety of hazardous chemicals, including carbon dioxide.
Therefore, the net effect of your electric vehicle on carbon emissions may be negative. But getting metal requires a lot of carbon, especially if miners don’t use renewable energy.
But that’s not all. In Germany, the manufacturing of a 500 kg electric vehicle battery produces more carbon dioxide than a conventional car does.
Global warming and unpredictable weather are mostly caused by the extraction of lithium and the manufacture of electric vehicle batteries.
Misuses Gallons of Water
Water is essential for the extraction of lithium. In order to extract one ton of lithium, 500,000 gallons of water are required.
According to studies, mining uses up over 65 percent of the water in Chile’s Salar de Atacama.
In many regions of the world, farming activities are halted because to the high water requirement. This may imply that mining the metal has minimal economic value and harms the environment.
Brine is pumped up from the subsurface pools by the producers, which is one of the most used methods for extracting lithium. The mixture is then concentrated in the evaporation pool by the sun. Lithium carbonate and lithium hydroxide are then precipitated by the miners by adding sodium carbonate and calcium carbonate.
For the precipitation process to start, the brine needs to lose up to 95% of the consumed gallons of water.
Lithium extraction causes an excessive amount of water to evaporate, as seen by the examination of the extraction process.
In the majority of arid and semi-arid mining locations, lithium extraction results in a severe water scarcity due to insufficient water supplies. As a result, it may increase the occurrence of cholera and other watery illnesses including dysentery.
The locations of lithium mining operations across the globe are all in arid, hot, and hilly terrain.
The top countries for lithium mining in 2018 were Australia, Chile, China, and Argentina. We’ve noticed that little has changed in that regard in 2021.
Lithium mining also prevents plants with shallow root systems from producing fruit and providing sustenance for themselves.
Depletes Fertile Land
The need for a lot of land for large-scale lithium production is another unpleasant truth. As a result, the majority of miners are forced to remove productive land from their local ecosystems. In these hot, dry, and mountainous locations, there are a few forests. Animals and plants must survive with the fewest possible resources.
The small areas of productive land become barren as a result of excessive lithium mining. Mining for lithium obliterates the habitats and minerals that are necessary for plant growth. Therefore, lithium extraction is to blame for the start of desertification in a number of global regions.
Causes Respiratory Problems
Chemicals found in lithium can impair the respiratory system in both humans and animals. The efforts of environmental conservationists who want to work with active, healthy people to replenish depleted resources are hampered by this health issue. And it kills.
Creates Unsustainable Water Table Reduction
Reducing the water table sustainably guarantees the availability of sufficient water sources. The top surface of the saturation zone is the water table. It completes the zone of saturation, which consists of water-filled cracks and pores in the ground.
The depth below which the ground is saturated is known as the water table.
Lithium mining causes irreversible water table decline and degrades soil structure. Ultimately, it exhausts water supplies, leaving the land too dry and putting ecosystems in danger of going extinct.
Produces Massive Mining Wastes
The process of mining lithium involves separating the valuable materials from the undesirable gangue. Some materials, referred to as tailings, are left over after this procedure.
The radioactive byproduct of uranium mining and sulfuric acid discharge are two of the most typical mining wastes. Numerous cancers and other illnesses may be brought on by them.
Other significant issues related to mining include significant wastes of lime and magnesium.
Given the quantity and toxicity of the wastes, local populations might not properly dispose of the leftovers. The environment and people may be faced with long-term difficulties as a result.
Tampers with the Water Cycle
Surface water is contaminated by the extraction of lithium. Other water sources are also destroyed. As a result, it contributes to the development of toxic rain.
The water cycle is heavily dependent on the few remaining woods because lithium is typically extracted in hot, arid, hilly regions. For this process to continue, trees draw water from the ground and release it into the atmosphere. Lithium mining therefore prevents the hydrological cycle from bringing enough rainfall to the impacted areas.
Now let’s move on to the remedies:
The Salton Sea has lithium, but where?
General Motors has already committed to purchasing lithium from CTR, and two additional businesses, EnergySource and Controlled Thermal Resources, or CTR, are also building combined geothermal-lithium plants at the Salton Sea.
Direct lithium extraction: what is it?
Lithium production to power batteries for electric vehicles has become a prominent topic due to the increased attention being paid to environmental issues and global warming. As a result, it is now clear how little the lithium business can do to meet its demands. Thus, our industry has received a lot of attention because it is predicted that there will be a 52 percent shortage of lithium production worldwide by 2030.
There are only two sources for commercial lithium production at this time: spodumene and naturally occurring brine that contains lithium. In earlier articles, the specifics of these resources—along with their benefits and drawbacks—have been covered.
The main topics of this essay will be brine resources and a specific method of lithium extraction known as direct lithium extraction, or DLE. Recently, it has been asserted by a number of proponents and commentators that DLE is a novel technology that holds the key to solving the lithium extraction problem. The Advanced Separations Laboratory of the Dow Chemical Company in the 1970s is where DLE actually got its start. The creator of ion exchange resin, Dr. William C. Bauman, founded and is the director of this lab.
After earning my PhD in physical chemistry in 1979, I had the good fortune to land a job at Dow as Dr. Bauman’s assistant. Bill’s main area of interest is lithium, even though the creation of effective, novel extraction technologies was our charter. He decided on lithium because he valued Dow and enjoyed solving complex puzzles. We consequently created a highly selective composite ion exchange resin during the course of the following five years that displayed dual selectivity for lithium and chloride ions. In 1984, we built and ran a pilot plant in Arkansas.
We showed that the direct lithium extraction technology could create high purity lithium chloride by extracting lithium from natural brines. The composite resin, while effective at removing lithium chloride from brine, has several major efficiency problems. The project was abandoned because the plant could not provide the necessary economics to enable commercial development.
Bill and I submitted two patent applications in 1992 for selective absorbents free of chelation or ion exchange. The Food Machinery Corporation later hired me (FMC). Early in 1994, FMC made the decision to license our inventions and launched a DLE operation at Salar Hombre Muerto in Argentina with the goal of removing lithium from saturated salt brine. I oversaw the program for developing absorbents and created the fundamental plant. The thorough engineering was carried out by an excellent team of engineers at FMC. The Salar Hombre Muerto lithium extraction facility owned by FMC opened its doors in 1998. Thus, in the 1980s, direct lithium extraction technology was developed, tested, and finally commercialized in 1998.
Intricacies of direct lithium extraction technology
With the use of direct lithium extraction technology, lithium and its associated anions are extracted from a brine solution and put into a new medium, such water, where they can be processed further to create finished goods.
DLE is simple to understand conceptually. One makes use of an extractant that will take out lithium ions in a complicated solution in a selective manner. The extractant is exposed to a brine containing lithium until equilibrium is reached. The extractant is “saturated” at this stage and won’t absorb any more lithium. This does not imply that lithium will necessarily be present at every site in the extractant. Lithium will compete with other positive ions, or “cations,” in brine solutions for specific places on the extractant.
As a result, an equilibrium will be achieved with all of the ions in the solution when an extractant comes into contact with a complicated brine solution. Multiple competing ions may be present on a single extractant particle, depending on the ion uptake process linked to a particular extractant. It’s critical to realize that basic thermodynamic principles underlie competition for extraction sites. The lowest enthalpy that can exist at a given temperature, with a certain extractant, and a particular solution composition is essentially represented by the ion “mix” on exchange sites of a particular extractant.
Lithium extraction and abandonment of the other cations are the clear objectives of DLE. But thermodynamics will prevail. Lithium must be associated with extraction sites in a way that is thermodynamically strongly favoured over other cations in the solution for economically viable lithium extraction to take place. The last examination is simple. The exchange sites are rebuilt following ionic equilibrium. The ratio of lithium to non-lithium cations, [Li]/[Na, K, Ca, Mg, Zn, Mn, etc.], will be what, though. This relationship describes the process’s extraction effectiveness and the purity of the lithium product.
So far, we have concentrated on particular ion interaction sites in the extractant. The brine is an equal participant in this interaction. Here are some of the properties of naturally occurring brines that make ion extraction extremely difficult:
1) Different natural brines exist in different resources and sometimes even in the same resource. Oilfield brines in North America can include extremely high concentrations of calcium, magnesium, iron, and silica in addition to lithium. In Southern California, geothermal brines contain silica, iron, manganese, zinc, magnesium, calcium, sodium, and potassium.
There are two industrial lithium solar evaporation operations in Chile’s Salar Atacama. Lithium, sodium, potassium, calcium, magnesium, sulfate, and borate are all present in this brine. The Atacama is a vast resource, and elements concentrations vary significantly from one salar to another. Sulfate and borate ions have a negative impact on the solubilities of several salts, including magnesium chloride, which is an issue for solar evaporation processes. Magnesium solubility considerably rises if these anion concentrations are too high. As a result, the clean removal of potassium magnesium chloride salts and magnesium chloride is not achieved. Instead, the magnesium follows the lithium through the remaining steps of the process and turns into a significant contaminant in the final lithium pond, which has a negative impact on the rates of lithium recovery.
2) Another problem is location. Andean brines are frequently found in extremely isolated areas where there is little availability to vital support services like labor, electricity, natural gas, or fresh water. In actuality, the majority of resource locations usually have one or more negative aspects.
3) While lithium concentrations are normally modest, total salt concentrations are frequently very high. There are occasional instances where total salt concentrations can surpass 350,000 mg/kg (parts per million), or 35 percent by weight, such as in Chilean, Argentinean, or American oilfield brines. These brines can contain sodium values of more than 100,000 mg/kg.
Target ion concentrations are hence very low. For instance, the lithium contents in commercial brine from the Salar Atacama typically vary from 1000 to 2000 mg/kg. In Alberta, some oilfield brines may only contain 50 mg/kg to 90 mg/kg.
The [Li]/[Na] ratio is 0.016 when we take into account a brine with a sodium concentration of 125,000 mg/kg and a lithium concentration of 2,000 mg/kg. Accordingly, the [Li]/[Na] ratio is 0.0004 if the lithium concentration is only 50 mg/kg. To reach our production targets, we will need to pump 40 times more 50 mg/kg brine than we would with 2,000 mg/kg brine, assuming a constant extraction efficiency.
Furthermore, larger lithium concentrations result in higher extraction efficiencies. As a result, even with very high flow rates and a 50 mg/kg brine, the lithium recovery will probably be lower. Lithium concentration is important.
4) In general, competing ions present in the brine can make lithium extractants highly sensitive. Ion-exchange-based extractants have a particularly challenging issue with this.
Why do so many direct lithium extraction processes fail?
Various strategies to extract lithium from brines have been proposed by and are being developed by a large number of firms. DLE start-ups are concentrated on identifying and developing processes for the selective removal of lithium from a source brine, with the exception of MGX’s failed attempts to thermally evaporate diluted Alberta brine using crystallisers to recover pure lithium chloride and millions of tons of unusable waste salt every year.
Solvent extraction, membrane separations, polymeric and inorganic based ion exchange, chelation and coordination schemes, combination exchangers, adsorption and absorption materials, and others have all been used by these firms in their effort to selectively recover lithium.
Our goal is not to thoroughly explore each idea. Instead, we are more concerned in outlining the formidable difficulties posed by direct lithium extraction technologies. We intend to clarify the fundamental ideas and, in the end, to outline a strategy that performs better.
The ion exchange concept
Ion exchange resin is the most prevalent class of commercial extractants. These materials are mostly used in applications for water filtration. They are used in the chemical sector to carry out a variety of duties as well. They are polymer beads made from open networked polymer resin, also known as macro reticular resin, or polymer “gel” resin. IX Resin is the usual name for polymer ion exchange resins. Inorganic materials with specialized characteristics that permit charge-based interaction with ions, such as zeolites or insoluble metal salts, can also form the foundation of ion exchangers.
Ion exchange is used in a very literal sense. IX resin quickly develops an ion distribution that differs from the initial salt solution’s or the end solution’s composition when it is dissolved in a salt-containing solution. The resin’s relative affinity to the various ions in solution—often referred to as the ion exchange selectivity—determines the distribution of ions within it. Selectivity coefficients for each exchangeable ion in the solution serve as its definition.
The selectivity coefficient for lithium vs sodium in a straightforward two-salt system, such as lithium chloride and sodium chloride, can be expressed as Ratioresin/solution. Valence and ionic radius are frequently the driving forces behind ion exchange selectivities. In general, monovalent cations like sodium or lithium are less strongly attracted to the resin than polyvalent cations like calcium. Large ionic radii have a stronger attraction to exchange sites than smaller radii do.
Because lithium is monovalent and has the smallest mass of all the periodic table’s cations, its connection with a cation exchanger in natural brine systems will be weaker than that of all the other cations. Notably, the only elements with smaller ionic radii than lithium are magnesium and beryllium. They are both divalent cations, though. The brines of interest do not generally include beryllium. Magnesium, however, is frequently found in substantial amounts. Ion exchangers will therefore choose to exchange magnesium instead of lithium.
Strong acid must be used to regenerate the resin once it has reached equilibrium with the source brine. A solid foundation is used to return the resin to its original form after this phase. The entire number of ions exchanged onto the resin along with any waste produced throughout the process will equal the total molar amount of acid and base. There is a substantial amount of waste salt solution produced throughout this regeneration process. Additionally, the lithium-containing regeneration product solution will be acidic and will need to be neutralized, resulting in the creation of even more waste salt solution.
Thus, the cost of huge quantities of acid and base as well as proportionately high volumes of water burdens each ion exchange cycle. Process engineers must also keep in mind that all of this used salt has to go somewhere. As a result, this regeneration operation presents a serious environmental concern.
Without a “magical” ion exchange material that can recover extremely high percentages of lithium in a single pass, the situation is unfortunately worse for ion exchange procedures. To increase the lithium concentration on the resin, the regeneration solution from the previous stage is passed through an additional ion exchange column in the following phase.
To achieve a suitable lithium concentration in the working solution, this multi-step procedure must be carried out repeatedly. Bottom line: Unless the IX system exhibits astounding selectivity for lithium, the entire process devolves into a monstrous Rube Goldberg nightmare with bad economics and significant environmental problems.
The chelation and coordination method
Chelation and coordination systems are being used by other DLE organizations. The majority of these methods relate to IX, as was previously said. As a result, they are similarly committed to the cycles of acid-base regeneration. The majority of these procedures share many of the same issues as IX straight. The fact that chelation and coordination systems perform admirably on transition metal ions like cobalt, copper, nickel, and the like is a frustrating reality. However, as comparison to a lithium ion, these ions are gigantic. Large, enlarged electron orbitals in these transition metals are well-matched with coordinating functions. Lithium has two electrons, but the cobalt cation, Co++, has 25. Again, lithium ions cannot be reached without a unique circumstance.
The liquid extraction method
The majority of the time, water or brine cannot be mixed with liquid extraction materials. Chelation or ion exchange occurs at the organic/aqueous interface, which is how they work. John Lee, one of the outstanding chemists I worked with at Dow while we were conducting fundamental extractive research, investigated the utilization of specific complex ethers to extract Li through an association mechanism. In straightforward NaCl-LiCl systems, his systems performed amazingly well. However, the Li consistently showed very low selectivity when Ca, Mg, Zn, or Mn were added to the solution. John’s method proved useless because natural brines will typically have large amounts of at least some of these ions.
The selective absorption method
After experimenting with these materials at Dow, we came to the conclusion that direct lithium recovery would only be successful if an effective lithium extraction procedure could be developed for an ion “discriminator” that is specific to only Li. Luckily, Bill and I discovered one at the beginning of the 1990s. Lithium ions can enter the material’s crystal lattice thanks to its distinctive crystal structure. The crystal lattice prevents the entry of other cations.
A selectivity coefficient for lithium over all other cations that is basically unmeasurable results from this property of exclusive lithium uptake into the lattice. We’ve performed a ton of experiments with different brine compositions. Lithium is the only cation for which we have never seen lattice absorption. For instance, we have carried out numerous tests with a brine from South America that has 1200 mg/kg of lithium. The brine was saturated and included normal Atacama brine concentrations of calcium, magnesium, sulfate, and borate.
We can regularly lower the brine’s lithium content to less than 0.1 mg/kg. Additionally, after regenerating the absorbent, we created a water-based lithium chloride solution that comprises 99 percent lithium chloride. Regeneration is carried out in these procedures using water. No base or acid is required. In addition, in contrast to ion exchange systems, the absorbent reached lithium saturation in a single cycle. In order to capture lithium chloride, the industrial process will alternate between brine and water.