Lithium resources from brine deposits are attractive when the demand for lithium is expected to increase by nearly 500% during the next decades to correspond to the electrification needs of transportation and energy storage. One related problem is lack of freshwater for extraction of lithium from the mineral basins. A recent study, published in the journal Communications Earth & Environment, analyses the critical situation in South America.
The so-called Lithium Triangle is a high-altitude region across Chile, Argentina and Bolivia, where an arid climate and water-trapping basins have helped form an estimated 98 million tons of lithium deposits. This lithium source is very attractive for the battery industry, but extraction of the valuable metal from the brine to generate lithium carbonate or lithium hydroxide requires processing technologies, evaporative concentration or direct lithium extraction (DLE), which consume huge amounts of freshwater per tonne of lithium carbonate.
The researchers, representing five US universities, said that a major challenge with lithium mining in the Lithium Triangle is the lack of modern freshwater inflows from precipitation to sustain water resources for indigenous communities, unique flora and fauna, and mining operations.
Scarcity of freshwater can lead to stress in the water supply system and hydrology if lithium extraction reaches an industrial scale. One ton of lithium needs around two million litres of water. Rivers in the salt flats don’t flow into the ocean and they see very little precipitation. Freshwater use from surface water and groundwater (well pumping) occurs upgradient of the discharge zone, reducing freshwater flow to wetlands. Brine pumping for lithium mining usually occurs downgradient of the discharge zone in the brine aquifer and may reduce discharge to wetlands, although the effects of brine pumping on wetland discharge are buffered by hydrogeologic processes.
