Lithium recovery from high salinity brines in a circular economy framework

Lecturer: Dr. Victoria Flexer, CIDMEJu-Universidad Nacional de Jujuy, Argentina

Brief summary: Lithium salts are fundamental raw materials for the production of rechargeable batteries, which are in turn closely linked with a much wider penetration of both electric vehicles and renewable energies in our energy matrix. The technology currently in use for lithium recovery from continental brines entails the evaporation of huge water volumes in desertic environments. It also requires for brines to reside not less than a year in open air ponds, and is only applicable to selected compositions, not allowing its application to more diluted brines such as geothermal or produced waters from the oil industry. Lithium rich brines display TDS values in the order of 300 g L^-1, with Li⁺ being only a very minor component in the best scenario at 1.5 g L^-1. Thus, these brines could potentially be regarded as a source of a variety of raw materials.

Direct lithium extraction technologies (DLE) aim for lithium recovery from brines ideally without resorting to water evaporation. I will present results on different prospective DLE technologies from my research group. These are based in electromembrane processes, adsorptive materials, and thermal methods. The big challenge is to propose brine processing strategies that can potentially be implemented at a very large scale. For example, in order to produce 20,000 tonnes of lithium carbonate yearly, from a brine with 700 ppm Li⁺, and considering a 70 % Li⁺ recovery, about 21,000 m³ of brine need to be processed daily. Thus, the issue is how to apply or adapt relatively well-known separation principles to large volumes and to a highly complex and saline broth. At this extremely large processing scale, ideas that are straight-forward to implement at laboratory scale, such as changing the pH, or heating the brine, could become too high operational costs for industrial scale.

Victoria Flexer holds a degree in Chemistry and a PhD in Physical Chemistry from the University of Buenos Aires, Argentina. She has conducted post-doctoral research in Centre de Recherche Paul Pascal (France), the University of Queensland (Australia) and Ghent University (Belgium). Since late 2015 she is a research fellow from CONICET, the Argentinean National Scientific and Technical Council and a professor at the National University of Jujuy. She leads a research group working both on material synthesis for lithium batteries, and brine processing for the sustainable recovery of lithium and other raw materials from high salinity brines.