Rio Tinto produces battery-grade lithium from waste rock at demonstration plant

Pittsburgh — Rio Tinto has begun production of battery-grade lithium from waste rock at a lithium demonstration plant in California, marking the next step in scaling up a new lithium production process, the company said April 7. Developed at the Boron mine site, the process will help recover the critical mineral and extract additional value out of waste piles from over 90 years of mining at the operation.

An initial small-scale trial in 2019 successfully proved the process of roasting and leaching waste rock to recover high grades of lithium, Rio Tinto said.

The California demonstration plant has a design capacity of 10 mt/year of battery-grade lithium and will be run throughout 2021 to optimize the process. It will also inform a feasibility assessment for progressing to a production scale plant with an initial capacity of at least 5,000 mt per year, or enough to make batteries for approximately 70,000 electric vehicles, the company said.

"This is a valuable next step in scaling up our production of lithium at the Boron site, all from using waste material without the need for further mining," Rio Tinto Minerals chief executive Sinead Kaufman said in a statement. "It shows the innovative thinking we are applying across our business to find new ways to meet the demand for emerging commodities like lithium, which are part of the transition to a low-carbon future."

Rio Tinto's lithium pipeline also includes the Jadar lithium-borate project in Serbia, for which a feasibility study is expected to complete by the end of 2021.