Rio Tinto has commenced production of battery-grade lithium from waste rock at a lithium demonstration plant at the Boron mine site in California, United States. The demonstration plant is the next step in scaling up a breakthrough lithium production process developed at Boron, to 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. The demonstration plant has a design capacity of 10 tonnes per year of battery ... (full story)