Mining has not been a comfortable business for oil and gas giant ExxonMobil in the past but its plan to produce lithium, an important battery metal, should wipe away memories of past failure.
The difference lies in the technology to be used in extracting lithium from brine (saltwater) deep under the southern U.S. State of Arkansas, which has more in common with oil production than digging holes and crushing rocks.
But the real key to what ExxonMobil plans for its return to metal production is in a process called Direct Lithium Extraction (DLE) which is already being used in China and South America.
Rather than dry lithium-rich brine in the sun, a method which can take years, DLE uses a resin to capture lithium in brine using adsorption (the opposite of absorption) because the metal sticks to the outside of the resin and is not absorbed.
Shale parallel
Goldman Sachs, an investment bank, earlier this year compared the potential impact of DLE with the technologies which turned once overlooked shale into an important source of oil and gas.
“Much like shale did for oil, DLE has the potential to significantly increase the supply of lithium from brine projects,” Goldman Sachs said in a report titled: DLE: A Potential Game Changing Technology.
ExxonMobil said in a statement announcing the Arkansas project that the lithium it plans to produce will be branded Mobil Lithium. First production is expected in 2027.
Dan Ammann, president of ExxonMobil Low Carbon Solutions said lithium is essential in energy transition and ExxonMobil has a leadership role to play in paving the way for electrification.
“This landmark project applies decades of ExxonMobil expertise to unlock vast supplies of North American lithium with fewer environmental impacts than traditional mining operations,” Ammann said.
Obstacles to clear
But before it can claim success ExxonMobil has two obstacles to clear.
Firstly, it needs to demonstrate that a full-scale DLE project will enable it to produce competitively priced lithium from 10,000-foot-deep saltwater reservoirs, and secondly it needs to successfully re-introduce a metals business into a company steeped in oil and gas.
Early trials of DLE have been encouraging but what ExxonMobil is proposing to do in Arkansas is a substantial increase in anything currently operating.
A key test of DLE will be the ability to increase the recovery of lithium. Goldman Sachs estimates that conventional brine projects yield between 40%-and-60% of the lithium in liquid with final production taking months and sometimes years. DLE yields should be between 70%-and-90% with production in hours to days.
Hardrock lithium production favoured in Australia, currently the world’s biggest producer of the metal, operates at yields of between 60%-and-80% with production taking weeks to months
Ammann said the Arkansas project was a win-win-win.
“It’s a perfect example of how ExxonMobil can enhance North American energy security, expand supplies of a critical industrial material, and enable the continued reduction of emissions associated with transportation which is essential to meeting society’s net-zero goals,” he said.
But a look back in time shows that ExxonMobil was once just as keen on producing copper, zinc and other metals in South America, Canada and Australia, before selling its mining assets to focus on liquid fuels.
Culture clash
The exit from mining in the 1990s was seen at the time as an example of mining and oil not mixing well thanks to different capital investment requirements, and management culture.
Arkansas lithium could be different because it is a fluids-based mining project which will utilize ExxonMobil’s deeply entrenched skills which appear to be transferable.
There is also a common thread in the customer base, car makers have been using ExxonMobil products for decades and are now potential buyers of Mobil Lithium.
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