An initial small-scale trial in 2019 successfully proved the process of roasting and leaching waste rock to recover high grades of the metal, vital in the production of batteries that power electric vehicles (EVs) and most high tech electronics.
“We figured out how to chemically process nearly a century’s worth of mining waste to unearth battery-grade lithium”
Rio Tinto
Rio’s discovery of lithium at Boron was a fluke. The miner was actually testing Boron’s tailings to see whether the presence of gold was significant and found instead traces of lithium at a concentration higher than domestic projects under development.
“We were looking for gold… but we found something better than gold: battery-grade lithium – and the potential to produce a lot of it,” Alex Macdonald, senior engineer at the plant, said on the company’s website.
The project comes at a time when the US is pushing to both encourage the electrification of vehicles and reduce the country’s dependence on China for rare earths, lithium and other minerals needed for EV batteries.
The Biden administration has promised to convert the entire US government fleet — about 640,000 vehicles — to EVs. If the plan is successful, the total number of EVs in the US would increase by more than 50%.
Major leagues
Rio Tinto invested $10 million to build the pilot plant that will be able to produce 10 tonnes a year of lithium-carbonate. By the end of the year, and based on the trial’s results, it will decide whether or not to spend a further $50 million in an industrial-scale plant with annual capacity of 5,000 tonnes a year — enough for around 15,000 Tesla Model S batteries.
The projected production would be roughly the same as the capacity of Albemarle ’s Silver Peak mine in Nevada, which is currently the only lithium-carbonate producing asset in the country, according to the US Geological Survey.
If the project proves to be successful, Rio Tinto will invest $50 million in a plant with annual capacity of 5,000 tonnes of lithium a year — enough for around 15,000 Tesla Model S batteries.
Until now, the global miner’s incursion in the lithium market has been mostly limited to its 100%-owned lithium and borates mineral project in Jadar, Serbia. A feasibility study for the proposed mine is expected to complete by the end of 2021, Rio said.
Rio has produced borates — a group of minerals used in soaps, cosmetics and other consumer goods — for nearly a century in the Mojave Desert, about 195 km (120 miles) north of Los Angeles.
The world’s second-largest miner announced in March an agreement with renewable energy firm Heliogen to explore the deployment solar technology at the mine.
Rio Tinto is not alone on its quest for producing lithium in California. Lithium Americas (TSX, NYSE: LAC) is also advancing a major project that received final federal approval in January. The Thacker Pass lithium mine is expected to generate 20,000 tonnes a year of the battery metal once operational in 2023.
The plant at Boron is the company’s latest attempts latest to extract valuable materials from waste rock or by-products – including scandium from titanium dioxide production, as well as anhydrite and Alextra from its aluminum operations.
