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Lithium Extraction: Methods and How the Process Works

Home 9 Lithium Recovery 9 What Is Lithium Extraction and How Does It Work?

The world’s demand for lithium extraction is growing every day and is especially driven by an increased lithium use in new consumer electronic battery technologies and electric cars. While you’ve likely heard of lithium batteries, you might still want to know where all that lithium comes from and how it’s produced. If so, you may be asking, “What is lithium extraction and how does it work?”

Lithium extraction and processing can depend heavily upon the source of the metal, so in this article, we’ll take a look at some of the more typical lithium production strategies and how they compare.

What Is Lithium Extraction?

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Lithium is a highly reactive alkali metal that offers excellent heat and electrical conductivity. These properties make it particularly useful for the manufacture of glass, high-temperature lubricants, chemicals, pharmaceuticals, and lithium-ion batteries for electric cars and consumer electronics. However, because of its high reactivity, pure elemental lithium is not found in nature but is instead present as a constituent of salts or other compounds. Similarly, most commercial lithium is available in the form of lithium carbonate, which is a comparatively stable compound that can be easily converted to other salts or chemicals.

Lithium salts are found in underground deposits of brine, mineral ore, and clay, as well as in seawater and geothermal well brines/water. By definition, lithium extraction is a set of chemical processes where lithium is isolated from a sample and converted to a saleable form of lithium, generally a stable yet readily convertible compound such as lithium carbonate. Most lithium extraction processes entail some form of mining to reach underground deposits of lithium-rich minerals or brines.

While lithium is fairly abundant in both land and sea, only a few sources are considered economically viable. This is expected to change in the coming years as new technologies make extraction from alternative lithium sources more cost-competitive.

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mineral extraction

How Does Lithium Extraction Work?

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Commercial lithium arises from two major sources: underground brine deposits and mineral ore deposits. The methods of lithium extraction and processing vary depending upon the source material, and include the following:

Lithium Extraction from Brine

An overwhelming quantity of today’s lithium is extracted from liquid brine reservoirs that are located beneath salt flats, known as salars, most of which are located in southwestern South America and China. Other lithium-rich brine resources include geothermal and oil field brines, which are addressed below.

Lithium brine recovery is typically a straightforward but lengthy process that can take anywhere from several months to a few years to complete. Drilling is required to access the underground salar brine deposits, and the brine is then pumped to the surface and distributed to evaporation ponds. The brine remains in the evaporation pond for a period of months or years until most of the liquid water content has been removed through solar evaporation. Salar brines are very concentrated and, in addition to lithium, typically

contain potassium and sodium as well. Facilities usually operate several large evaporation ponds of various ages, and may extract other metals (e.g. potassium) from younger ponds while waiting for the lithium content to reach a concentration optimal for further processing. In some cases, reverse osmosis (RO) is used to concentrate the lithium brine.

Once the brine in an evaporation pond has reached an ideal lithium concentration, the brine is pumped to a lithium recovery facility for extraction. This process varies depending on the brine field composition, but usually entails the following steps:

● Pretreatment: filtration and/or ion exchange (IX) purification to remove contaminants.

● Chemical treatment: Chemical solvents and reagents isolate desirable products and byproducts through precipitation.

● Filtration: The brine is filtered to separate out precipitated solids.

● Saleable lithium production: The brine is treated with a reagent, such as sodium carbonate, to form lithium carbonate. The product is filtered and dried for sale. Other reagents may be used to produce lithium hydroxide, lithium chloride, lithium bromide, and butyl lithium.

Once the lithium extraction process is complete, the remaining brine solution is returned to the underground reservoir.

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Hard Rock Lithium Extraction

While accounting for a relatively small share of the world’s lithium production, mineral ore deposits yield nearly 20 tons of lithium annually. Well over 100 different minerals contain some amount of lithium; however, only five are actively mined for lithium production. These include spodumene, which is the most common by far, as well as lepidolite, petalite, amblygonite, and eucryptite.

Mineral ore deposits are often richer in lithium content than salar brines, but they are costly to access since they must be mined from hard rock formations. Due to the added energy consumption, chemicals, and materials involved in extracting lithium from mineral ore, the process can run twice the cost of brine recovery, a factor that has contributed to its smaller market share.

The process for recovering lithium from ore can vary based on the specific mineral deposit in question. In general, the process entails removing the mineral material from the earth, then heating and pulverizing it. The crushed mineral powder is combined with chemical reactants, such as sulfuric acid, then the slurry is heated, filtered, and

concentrated through an evaporation process to form saleable lithium carbonate, while the resulting wastewater is treated for reuse or disposal.

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Alternative Lithium Extraction Methods

Beyond salar brine and mineral ore, lithium can be produced from a few other sources, though such production is not widespread at this time. These other lithium sources include:

● Hectorite clay: Research and development is ongoing, but no technology has proven economically viable yet.

● Seawater: Oceans contain large amounts of lithium. Some processes have succeeded in extracting lithium from seawater, and newer membrane technologies are showing greater promise for bringing the costs of seawater extraction down.

● Recycled brines from energy plants: Efforts to retrieve lithium from geothermal brines are increasing as demand grows and new technologies emerge.

● Recovered oil field brine: This is another form of conventional brine extraction, with the source being oil field brines.

● Recycled electronics: Lithium battery recycling is becoming more valuable as demand increases, though it is not technically extraction.

While each of these poses a potentially valuable source of lithium, the technologies to extract lithium from them are not yet developed enough to make them cost-effective or viable alternatives to salar brine mining or mineral ore mining.

Can SAMCO Technologies help?

SAMCO has over 40 years’ experience in identifying appropriate brine and water treatment solutions to help lower costs and waste volumes while increasing lithium production yields. For more information or to get in touch, contact us here to set up a consultation with an engineer or request a quote. We can walk you through the steps for developing the proper solution and realistic cost for your lithium processing and system needs.

To learn more about SAMCO’s innovative technologies that we commonly apply for lithium production facilities, visit our page on brine and lithium recovery, softening, and purification.

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