A new and possibly more environmentally friendly way to mine lithium could make it easier to extract the critical mineral from deposits in Western Canada, as companies move closer to demonstrating that the technology works at scale.
Such lithium is found in very salty water underground known as lithium brines and has not been easily accessible with conventional methods. Now, a technology called direct lithium extraction (DLE) could allow companies to mine those resources, at a possibly lower cost to the environment than other methods.
Alberta is particularly attractive to at least one such company because its long history of oil and gas extraction has “left behind an incredible amount of infrastructure that we are trying to repurpose,” said Kevin Piepgrass, chief operating officer of LithiumBank, a mining company that’s trying develop lithium resources in the province.
It holds licences for two lithium projects in Alberta, about 200 to 300 kilometres northwest of Edmonton, and is using wells that were built decades ago to extract oil and gas, to instead access the underground brines that contain lithium — an essential ingredient in the batteries that are powering the clean energy transition.
“It’s an incredible opportunity to produce lithium from an area that has all these things that you need,” Piepgrass said, referring to Alberta’s favourable regulations and the availability of water and power for the mining sector.
Something similar has happened in Alberta before: its oilsands only became financially successful in the 1970s when prices went up and the technology to extract the oil improved.
DLE versus other methods
Currently, lithium comes from two main sources: Traditional mining from rocks, used in Australia, which supplies a third of the world’s lithium, and extraction from lithium brines, mostly in South America, especially Chile’s Atacama desert.
In places like Chile, the lithium brine is pumped to the surface and left to dry over a long period time until the lithium gets highly concentrated.
Ngai Yin Yip, a professor of earth and environmental engineering at Columbia University, says that only works in arid environments where the water can evaporate.
“You have all the solar energy to do that evaporation, but there are a lot of other places where you have this lithium brine but you do not have this abundant cheap land and you do not have the right conditions for evaporation to take place,” he said.
“We can only depend so much on South America for lithium production, which is why there’s a really strong interest in … new technologies that can produce lithium from different sources, including lithium brines,” he said.
That’s where Canada’s brines come in, where the brine cannot be left to dry out. But Yip researches DLE methods which cut the need for solar evaporation by using chemicals to extract the lithium directly.
Yip’s team just released a study about a new solvent they have shown can extract lithium from brine.
So far, it’s only been demonstrated to work in the lab, showing promise but also the challenge of using DLE technology at scale.
Piepgrass, whose company is trying out a different DLE process, says picking the right technology depends on where the brines are.
“There’s a lot of the details that go into it. And then, what kind of product do they produce? Are they compatible with your downstream processing?” he said.
LithiumBank pilot-tested its technology last year, and says it was able to successfully extract battery-grade lithium. It is now working on a more detailed feasibility study and more tests to demonstrate the quality of the lithium it can extract.
At the moment, Canada’s only has two lithium mines, in Manitoba and Quebec, both extracting it from hard rock.
Canada produces 6,000 tonnes of lithium per year, compared to Australia’s 88,000.
Demand for lithium worldwide is set to grow to nearly eight times its current level, reaching 1.3 million tonnes, by 2040, according to projections from the International Energy Agency. It is needed in electric vehicle batteries, and to store power as part of large electric grids that rely on renewable energy like solar and wind.
What is the environmental impact of this?
DLE is better for the environment than other forms of extraction, but only if the process uses clean energy, according to Ehsan Vahidi, assistant professor of extractive metallurgy at the University of Nevada, Reno.
Vahidi’s team put out a paper last year that compared the environmental costs of lithium extraction through the three major methods — hard rock mining, evaporative extraction from brines, and DLE.
Vahidi’s team focused on carbon emissions, land use and water use of the different lithium extraction methods. They focused on carbon emissions, land use, and water use of the different lithium extraction methods.
(Ivan Alvarado/Reuters)
The largest lithium producer, Australia, had some of the highest emissions. That’s because mined material is sent to China for processing, and emissions were driven up by the shipping as well as the energy used in China, which relies heavily on burning coal.
Lithium brine projects in South America had some of the lowest emissions, since they rely on solar heat. Conversely, they use up a lot of land — 350 to 600 square metres per ton of lithium carbonate equivalent, compared to just 16 square metres for DLE.
The main environmental impact of DLE, Vahidi says, was energy emissions. It uses a lot of energy to pull out and process the thousands of litres of brine water. Vahidi’s study suggested those emissions can be reduced by using renewable energy, like solar.
The electricity grid in Alberta relies on fossils — most of the energy comes from gas. But the province is also a major centre for solar energy development.
“Everything about lithium is about trade off. You are losing something, you are gaining something else,” Vahidi said.
And, he pointed out, DLE saves a lot of water — nearly all of it can be returned to the ground after lithium extraction.
“If you have a reliable and sustainable electricity generation system, DLE is one of the best ways to recover lithium from the ground,” he said.
