Researchers have developed an effective method to cost-effectively extract lithium from seawater at a purity of 99.94 per cent while also creating freshwater.
The research team from King Abdullah University of Science and Technology in Saudi Arabia devised an electrical cell consisting of a cathode compartment, a feed compartment and an anode compartment.
The cathode and feed compartments were separated by a dense glass-type membrane which the report found was highly durable to the activity.
“Indeed, it was found that the LLTO membrane could be used for more than 2000 hours with a negligible decay in performance,” the report stated.
The seawater was passed through the cell over five stages, taking 20 hours.
After filtering and refiltering at each stage, the original lithium concentrate of 0.21 parts per million became almost 9000 parts per million (ppm).
The findings, published in Energy & Environmental Science, found just how much power would be necessary to extract a kilogram of lithium.
“Based on these data, we estimated the total electricity required to enrich one kilogram of lithium from seawater to 9000 ppm in five stages to be 76.34 kilowatt-hours,” the report stated.
The benefits of the experiment were multi-faceted, as cost and biproducts also became important.
“Taking the US electricity price of $US0.065 (~$0.09) per kilowatt-hour into consideration, the total electricity cost for this process is approximately $5,” the report stated.
“It is also noted that the total concentration of other salts after the first stage is less than 500 ppm, which implies that after lithium harvest, the remaining water can be treated as freshwater.
“Hence, the process also has a potential to integrate with seawater desalination to further enhance its economic viability.”
The researchers believed this could leave to exciting progress in future electrification practices.
“It is expected that our approach will lead to the development of a promising process to secure the supply of lithium for future energy uses,” the report concluded.