Environmental impact of direct lithium extraction from brines

VERA, MARÍA L.; TORRES, WALTER R.; GALLI, CLAUDIA INÉS; CHAGNES, ALEXANDRE; FLEXER, VICTORIA

Nature Reviews Earth & Environment

Springer Nature

Año: 2023 vol. 4 p. 149 - 165

Evaporitic technology for lithium mining from brines has been questioned for its intensive water use, protracted duration and exclusive application to continental brines. In this Review, we analyse the environmental impacts of evaporitic and alternative technologies, collectively known as direct lithium extraction (DLE), for lithium mining, focussing on requirements for freshwater and chemicals, energy consumption and waste generation including spent brines. DLE technologies aim to tackle the environmental and the techno-economic shortcomings of current practice by avoiding brine evaporation. Li+ recovery above 95%, Li+/Mg2+ separation above 100, and zero chemical approaches have been achieved for selective DLE. Conversely, only 30% of DLE test experiments were performed on real brines, and thus the effect of multivalent ions or large Na+/Li+ concentration differences on performance indicators are often not evaluated. Some DLE technologies propose brine pH changes or brine heating up to 80oC for improved Li+ recovery, which require energy, freshwater, and chemicals that must be considered during environmental impact assessments. Future research should focus on performing tests on real brines and achieving competitiveness in several performance indicators simultaneously. The environmental impact of DLE should be assessed from brine pumping to the production of the pure solid lithium product.