It hasn’t stated whether it intends to go public, which could be challenging given the state of the market. Over the course of six rounds of fundraising, Lilac Solutions has so far secured a total of $174 million. In September 2021, Lilac held its most recent investment round, which brought in $150 million from investors.
How is lithium extracted?
A mineral-rich brine that is located ten meters beneath the salty lakes of high-altitude salt flats is where the majority of the world’s lithium is harvested. Drilling through the crust is the first step in the procedure, after which the brine is pumped to the surface and placed in evaporation pools where it is stored for months at a time. This results in the formation of a salty mud that is then transferred to another open-air evaporation pool and contains a mixture of manganese, potassium, borax, and lithium salts.
Lithium carbonate, the primary raw material used in lithium ion batteries, may be extracted from the mixture after 12 to 18 months of distillation.
In the so-called “Lithium Triangle,” which includes Bolivia, Chile, and Argentina, this method of extraction is frequently employed. This approach is advantageous since it is inexpensive and efficient at extracting lithium carbonate. However, the procedure uses a lot of water.
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.
IBAT’s direct lithium extraction technology
We have been attempting to combine this selective absorbent with a very effective modular and mobile extraction equipment for the past four years. First, Drs. John Burba and Bill Bauman’s’selective absorbent’ was improved upon for use in IBAT’s direct lithium extraction method in the early 1990s. As previously mentioned, this absorbent will preferentially remove lithium and chloride ions from high salinity brines.
Other salt components like sodium, potassium, calcium, magnesium, sulfate, and borate are rejected by the sorbent. Contrary to almost all other DLE systems, IBAT’s process runs on a brine-water cycle. The brine’s lithium chloride is taken up and discharged into the water. Acid and base are not required, in contrast to other DLE procedures. Therefore, the IBAT process does not involve the associated waste salts. A cleaner operation is naturally created by this.
Previous significant differences between other suggested DLE procedures and the patented process developed by IBAT exist.
1) The IBAT plant is portable and modular. This implies that we can quickly construct our entire plant in a fabrication shop. Construction and startup times for conventional lithium extraction operations range from five to twelve years. As a result, IBAT’s plants will be substantially less expensive than conventional plants.
The modules of IBAT can also be carried and put together at the resource. The advantages go beyond just saving money and time. There is also a significant environmental benefit. Large structures on substantial concrete foundations are a feature of conventional facilities, and they will continue to exist long after the activity is complete. IBAT will relocate the apparatus to a new position whenever an operation is complete. We’ll leave the area spotless.
2) The IBAT plant is built to cause as little environmental harm as possible while extracting lithium. We have included a number of cutting-edge, highly eco-friendly technology.
a) About 98 percent of the plant’s process water is recycled thanks to new water recovery technology created by IBAT. Large amounts of fresh groundwater are needed for solar evaporation plants to function. In locations where native peoples farm and ranch, this has been a serious issue. IBAT won’t contend with locals for limited water supplies. We won’t need local water because of our advancements in water recovery.
b) IBAT prefers to reintroduce lithium-depleted brine into salars in Chile and Argentina with the approval of national authorities. The US’s extensive historical record demonstrates that this process may be carried out successfully. The benefit is that we won’t be contaminating large resource areas with copious amounts of salt waste.
c) Our procedure is set up to reduce the carbon imprint we leave behind. In our plants, we intend to use renewable energy. We’re going to use solar power. Additionally, we are looking into various cutting-edge, fascinating renewable energy technologies that can provide both thermal and electrical energy.
IBAT’s new, patented direct lithium extraction process is built on cutting-edge engineering and tested selective absorbent technology. The ethical advancement of the lithium extraction and production business is our main objective.
Please be aware that this essay will also be included in our quarterly publication’s tenth edition.