The researchers at the Karlsruhe Institute of Technology (KIT) may have felt a bit like finding a hidden treasure when they succeeded recently in extracting lithium from an unusual source: thermal water.
As lithium has come to be the most important raw material for making modern-day batteries, countries rich in the mineral like Chile, Argentina, Bolivia and Australia, are the focus of a global push aimed at securing a steady supply.
Millions of tons of lithium are needed by battery makers from across the world, and the four countries account for more than 80% of annual supply currently. So, many countries, including Germany, are hugely dependent on global lithium market pricing and supply — but this could change if the new technology developed by KIT becomes widely adopted.
The presumptive pot of “white gold” struck by the Karlsruhe, Germany-based institute lies in the deep crusts of the Oberrheingraben, or Upper-Rhine Rift Valley, situated in southwestern Germany.
Deep down in the ground of the region, you can find salty hot water that is already used in thermal power and heating plants. But KIT has also found that the brine contains liquid lithium, among other minerals.
“We’ve discovered amounts of up to 200 milligrams per liter [of thermal water],” KIT said in a recent statement unveiling its findings. And Jens Grimmer, a researcher at KIT’s Institute for Applied Geosciences (AGW), told DW that the deposit, if fully explored, could provide “a significant amount” of the lithium needed in Germany.
Grimmer, together with a fellow researcher — Florencia Saravia from KIT’s Engler-Bunte Institute — has developed a technology designed to extract the lithium in a sustainable, environmentally friendly and cost-efficient way.
The pair now has a patent on the unique technology, which Grimmer says, could help Germany meet its climate goals amid rising demand for lithium due to growing electric vehicle battery production.
“In a first step, the lithium ions are filtered from the thermal water, and then concentrated in a second processing step until the lithium precipitates as a salt,” he explains.
Tweaking existing infrastructure
According to KIT, the Grimmer-Saravia technology has a number of advantages over conventional lithium mining methods used in South America and Australia.
In Germany, the process will use existing geothermal-power infrastructure that already pumps about 2 billion liters (500 million gallons) of thermal water from underground deposits every year.
Underground hot salty water is widely used in the Upper Rhine Rift Valley to heat houses and generate power
And contrary to conventional lithium mining, which taps into huge salt lakes or rock formations, soil loss and land use would be minimal. Additionally, the thermal water would be pumped back into the ground only after power and heat extraction — and without hazardous or even toxic chemicals.
Thanks to the thermal water cycle,…