Novalith Technologies ($17M for using CO2 to extract lithium)

Novalith Technologies, an Australian climate tech startup founded in 2020, has developed lithium extraction technology that uses carbon dioxide (CO₂) and water instead of concentrated sulfuric acid to directly extract lithium from spodumene ores as technical grade lithium carbonate (Li₂CO₃) / lithium bicarbonate (LiHCO₃). Novalith’s technology reduces significantly the amount of equipment, chemical reagents, water, and energy needed for the lithium extraction process and converts CO₂ into valuable products.

Challenges: lithium extraction

Lithium demand

In the past few years, the need for lithium-ion batteries has grown quickly. This is mostly due to the growing popularity of electric vehicles (EVs) and the need for ways to store energy. In 2022, the demand for lithium-ion batteries in cars rose by about 65%, from about 330 GWh in 2021 to 550 GWh. By 2030, the global demand for lithium-ion batteries is expected to reach around 4.7 TWh, with most of that demand coming from batteries for mobility applications.

Lithium-ion batteries are becoming more and more popular, and this is driving the need for lithium. Even though production has gone up by 180% since 2017, demand for lithium will be higher than supply in 2023.

Lithium extraction from brines

As a result of its high chemical reactivity, lithium metal does not occur in nature. From brine and minerals, commercial lithium compounds are extracted.

In general, brine extraction is less expensive and more commercially viable than ore extraction. The conventional method is straightforward and heavily dependent on evaporation. Typically, brine is pumped from the subsurface to the surface and into a network of evaporation ponds. Over a period of months, the water slowly evaporates, and a variety of salts precipitate out, leaving a brine with an ever-increasing concentration of lithium. This method is labor-intensive and can take anywhere from several months to several years to complete. A technical grade lithium salt (98-99%wt) is obtained.

However, the brine extraction industry is restricted geographically. Almost all of the major brine lakes are located in remote areas (e.g., in the Andes region bordering Argentina, Chile and Bolivia).

Lithium extraction from ores

Only high-grade pegmatites, such as those extracted from Greenbushes, are currently competitive with brines. Australian pegmatitic spodumene currently supplies approximately 33% of the global lithium market. Spodumene is a pyroxene mineral that is composed of lithium aluminum inosilicate (LiAl(SiO₃)₂).

There are two methods for extracting lithium from spodumene: acid leaching and carbonate leaching. Both methods require calcination of the spodumene at around 900 ºC to convert α-spodumene to the β-spodumene.

Acid leaching of β-spodumene involves mixing concentrated sulfuric acid (96%) and β-spodumene at 250 ºC in a sulfating kiln to form soluble lithium sulfate according to the reaction below:

2LiAl(SiO₃)₂ + H₂SO₄ → Li₂SO₄ + Al₂O₃ + 4SiO₂ + H₂O

During sulfation and leaching, significant amounts of Fe, Mg, Mn, Na, and Al are also leached from spodumene. Typically, these impurities are precipitated and separated from the solution by adding soda ash (Na₂CO₃) and caustic soda (NaOH). After crystallization with soda ash, technical grade lithium carbonate (98-99%wt) product is precipitated.

The carbonate leaching, also known as Quebec process, involves mixing β-spodumene with water to produce a fine-grained slurry and then adding soda ash (Na₂CO₃) at 215 ºC and about 2,140 kPa in a pressure vessel. After injecting CO₂ gas, the insoluble lithium carbonate (Li₂CO₃) is converted into the more soluble lithium bicarbonate (LiHCO₃). At this stage impurities including Na, Al, and Fe precipitate and are separated. By driving off CO₂ which is then recycled in the process, lithium carbonate of 99% purity is crystallized.

Acid leaching and carbonate leaching can be costly, inconvenient and harmful to the environment. In addition, the sequence of extraction steps required to obtain technical grade lithium carbonate for commercial sale can be labor-intensive. Therefore, it is necessary to overcome the aforementioned disadvantages of mineral extraction.

Novalith Technology

Novalith has developed lithium extraction technology that extracts lithium from β-spodumene using weak acid of carbonic acid (H₂CO₃) instead of concentrated sulfuric acid. Spodumene ores are first milled into fine particles and calcined at temperatures above 900 ºC to convert α-spodumene to the β-spodumene. The β-spodumene particles are mixed water in a 150 ºC reactor. Injecting pressurized CO₂ and water mixture into the reactor, the weak carbonic acid (H₂CO₃) extracts dilute lithium from β-spodumene into the aqueous phase. Lithium carbonate/lithium bicarbonate solution is concentrated using reverse osmosis, and technical grade lithium products are obtained.

Novalith lithium extraction process

The diagram below depicts Novalith’s lithium extraction process from β-spodumene using carbonic acid (H₂CO₃).

Novalith lithium extraction from spodumene using carbonic acid (ref. US11371116B2).

In a high pressure low flow mixing tee, a water stream and a pressurized CO₂ gas stream are mixed. The mixture is preheated before entering a reactor operating at 150 ºC and 100 bar and containing an aqueous suspension of β-spodumene. Some CO₂ gas is dissolved in water and form weak carbonic acid (H₂CO₃). Carbonic acid dissociates into bicarbonate (HCO₃⁻) and proton (H⁺). In the reactor, the weak carbonic acid is responsible for the extraction of Li from β-spodumene.

However, the maximum lithium concentration extracted into the aqueous phase is 100 ppm (0.015 mol/L), which is insufficient to precipitate lithium carbonate (Li₂CO₃)/lithium bicarbonate (LiHCO₃) of technical grade.

Novalith has used reverse osmosis (RO) to concentrate the dilute lithium solution to the required concentration (5,000 ppm or 0.7 mol/L) in order to precipitate lithium carbonate/lithium bicarbonate of technical grade. As the process is already under pressure, RO is well suited to this process. Additionally, RO produces a purified permeate stream that can be recycled in the extraction process. Recycling the leachate water reduces the process’s water consumption and facilitates the maintenance of dilute extraction conditions.

Novalith Patent

US11371116B2 Lithium extraction method

Novalith Products

Novalith’s LiCAL® technology is a new way to extract and refine lithium. Instead of using strong acids or bases, it uses CO₂ to extract lithium from ores and turn them directly into battery-grade lithium products.

The LiCAL® process is better than other ways to extract lithium in a number of ways. It cuts process costs by up to 65%, plant costs by up to 50%, and plant footprints by up to 25%. Also, it uses 90% less water than current methods and could be used with renewable energy sources to make lithium production carbon-negative. The technology is also better for the environment because it makes inert bulk by-products and makes extracting and refining lithium much easier on the environment.