Producing lithium with a smaller environmental footprint
Solvay’s specialty reagent for cost-effective lithium production
Global demand for lithium is increasing rapidly. It is driven by strong growth in the electric vehicle market, particularly in Europe, as lithium is a crucial element in car batteries. This is a market expected to grow threefold by 2030, according to the International Energy Agency.
Until recent years, the majority of the world’s lithium was used for industrial applications such as ceramics, lubricants and pharmaceuticals, and only a minority went into batteries. But because of growth in electric vehicle demand, that balance is changing quickly. In 2019, 65% of the world’s lithium went into batteries, and this proportion will continue to grow.
Lithium is produced from two different sources: ore bodies that are mined (chiefly in Australia and Canada), and evaporation from salars in South America’s ‘lithium triangle’ (which overlaps bordering regions of Bolivia, Argentina and Chile). Salars are large expanses of underground saltwater that contain significant quantities of lithium. The problem with the evaporation method is that it requires depleting massive amounts of water from ecosystems.
Looking to tackle this issue, Solvay partnered with mining engineering firm Tenova Advanced Technologies to offer South American lithium producers a new, more environmentally sustainable and cost-effective production process based on solvent extraction.
Faster and more sustainable
Our mining solutions team came up with an optimized extractant formulation for the Tenova LiSX™ process based on solvent extraction. CYANEX® 936P enables the production of high-purity lithium salts in a matter of hours, rather than 12 to 18 months under conventional evaporation methods, and regardless of weather conditions. With this new process, the lithium-free (and unpolluted) saltwater can be re-injected into the salar, saving billions of liters of water. The product also helps reduce the operators’ environmental footprint by eliminating the need for large evaporation ponds.
“The way we extract the lithium is by contacting the brine with an organic solvent containing our CYANEX® 936P extractant,” explains Laurent Cohen, Global Marketing Manager for Metal Extraction Products at Solvay. “This is a closed-loop, liquid-liquid process that allows the return of the brine to the salar after the lithium is extracted. In terms of sustainability, time and cost benefits, there’s no other process in the market that competes at our level. With this product, Solvay is pushing the boundaries of solvent extraction technology.”
Though it is part of the CYANEX® range of organo-phosphorous molecules produced at Solvay’s plant in Welland, Ontario (a unique facility for phosphorus derivatives), CYANEX® 936P was specifically developed to ensure its selectivity. In other words, when the water containing the lithium is put in contact with the solvent containing the extractant, only the lithium transfers to the solvent, leaving the other metals and minerals (such as sodium, which is of course rife in saltwater) in the aqueous phase. “Since we return the brine to its natural environment, the salar remains intact,” continues Laurent. “The original lithium contents in the brine is in the order of one tenth of a percent, and the volumes pumped are insignificant in comparison to the overall brine reserve. Therefore, reinjecting the lithium-depleted brine into the salar bears absolutely no impact on the ecosystem, no more than that of a desalination plant returning an infinitesimal flow of slightly saltier water into the immensity of the sea.”
Creating value from waste
There are also financial and strategic arguments for adopting new lithium production methods for South American operators. In addition to the fact that it’s more efficient and quicker than the evaporation process, solvent extraction provides the additional benefit of enabling the direct production of lithium hydroxide, a higher-value product than lithium carbonate. As converting their lithium carbonate output into hydroxide is extremely costly for South American operators, the direct production of lithium hydroxide from brines via solvent extraction is a unique, economically-viable opportunity for them to compete with the Australian hydroxide producers.
In terms of sustainability, time and cost benefits, there’s no other process in the lithium production market that competes with our solvent extraction method.
Lithium hydroxide is the compound that is used in so-called “nickel-rich” lithium-ion batteries, the newest generation of electric vehicle battery chemistries. By contrast, the lithium carbonate produced by brine evaporation is only suitable for industrial applications and earlier generations (“cobalt-rich”) of battery chemistries. As nickel-rich chemistries are slowly set to dominate the EV battery landscape, lithium hydroxide is forecasted to represent the lion’s share in global lithium demand and command a price premium in the market.
Moreover, Solvay has come up with another solution to help lithium producers improve their revenue with minimal additional expenditures and an added environmental benefit: exploiting an untapped resource from waste in the current production process. “In the traditional evaporation process, there is, in the carbonation step, an effluent called ‘mother liquor’ that contains a few grams per liter of lithium. This lithium typically goes by the wayside but can represent up to 10% of the facility’s overall production,” explains Laurent. “If operators were to extract that lithium, they would be able to increase their production by 5-10% without needing to pump more water from salars and with reasonable investments.”
So, Solvay’s teams developed a new value proposition: building small treatment plants that can extract the lithium currently going to waste from the mother liquor and boost revenues with close to zero risk. And as an added bonus, the end product from this process is lithium hydroxide, not carbonate. “Thanks to our reagent, we can now help all South American producers enter the more lucrative and strategic hydroxide market while de-risking the transition, as the small mother liquor treatment plants don’t require massive investments,” explains Laurent.
“With this new proposition,” he continues, “we are in a position to cater to two different scenarios: ‘mother liquor’ extraction for existing evaporation process operators interested in accessing the higher-value market of lithium hydroxide while limiting their investment and operations costs, and providing ‘full process’ solvent extraction solutions for new players who aren’t interested in investing in evaporation pond infrastructure and seek the full value of direct extraction.”
Whatever the scenario, making lithium production in South America less resource intensive is a clear and attainable objective thanks to CYANEX® 936P, one of Solvay’s many solutions to improve resource efficiency around the world!