MINING THE BRINE
Lithium carbonate is extracted from the salt desert by piping brine from below the crust into large evaporation pools. Three litres of Salar de Uyuni brine contain less than a gram of lithium metal, so it is concentrated under the glare of the Sun before being collected for processing. The lithium at Salar de Uyuni is also bound up with magnesium, which has to be removed before the lithium can be turned into electrodes and electrolytes for batteries.
Right now, there is only one working pilot plant at the salt flat, where, as former director of communications for the plant, Raúl Martinez, explains, 99.7 per cent pure, battery- grade lithium is being produced. “This project demonstrates that the Bolivians have all the potential to obtain lithium carbonate of commercial and battery- grade in the salt flats,” he says. However, the state mining company Comibol may need to scale up its operations. It shipped less than 30 tonnes of lithium carbonate in 2016, making the target of 10,000 tonnes by 2021 seem like a stretch. Bidding for construction of a second plant, designed by German company K-UTEC, is underway.
MAIN IMAGE: Evaporation pools, separated by levees, concentrate the lithium BELOW RIGHT: Lithium- rich brine is pumped from beneath the crust