Researchers at Lappeenranta University of Technology in Finland recently completed work examining new methods of extracting lithium from natural brine sources — revealing that the new methods allow for an increase in the purity of the recovered lithium solution from around 95% all the way up to 99.9%.
Accomplishing such a high degree of purity through traditional methods is much more difficult and resource intensive, according to those involved.
The work is worth covering here, as lithium is one of the primary materials used in the creation of lithium-ion batteries — which are currently (and likely for quite a while longer) the dominant battery technology modality in use in electric vehicles. With an increase in electric vehicle and home energy system sales and market presence, associated resource prices (such as lithium prices) may well rise without new, cheaper extraction methods.
A new press release from Lappeenranta University of Technology (LUT) provides more:
Lithium and lithium carbonate used in accumulators are primarily produced from salt lake deposits. Prior to the actual separation process, the brine is pumped up and concentrated by evaporation of water which usually takes place in large pools under the sun. Finally, the concentrated solution is led into a process in which the solution is purified of impurities and the lithium is separated.
At LUT, solvent extraction has been used for purifying the solution. In this process, the separation occurs between two insoluble liquid phases. In this case, impurities, calcium and magnesium were separated from the concentrated lithium salt solution into an organic solution consisting primarily of kerosine.
“We were typically able to purify 99–100% of calcium and also over 90% of magnesium. Lithium loss only amounted to 3–5%. In traditional methods, the purification outcome is either weaker, the lithium loss is more substantial, or both,” commented Sami Virolainen, a post-doctoral researcher at LUT.
The new work was done at the pilot-scale (flow rates during extraction varied from 1-5 liters/hour) rather than the commercial-scale of course, but the process could be scaled up.
“On the industrial scale, we are talking about a cube or dozens of cubes per hour. However, the process has been constructed similarly as it would be in the industry, i.e., constant streams go in and come out and the number of processing phases is the same as in an industrially conducted extraction.”
Virolainen argues that the new solvent extraction method “is a profitable alternative to an extraction process when the product is required to have the purity of nearly 100% and a high recovery of the target metal is demanded.”
“The extraction process we use is more expensive than regular precipitation but, as the study indicates, separation is more efficient and easier. This simplifies the overall process, which also makes it an economically sensible alternative,” he continued.
Interestingly, the new method is also well suited to the extraction of lithium from electronic waste.
Virolainen made a salient point on that matter: “The need for lithium might increase by up to 4 times by the year 2025. As the demand grows, recycling of products containing lithium and the use of new alternative sources for raw material must be increased.”
Image Credit: (Lithium in Paraffin) Public Domain