Technological tendencies for lithium production from salt lake brines: Progress and research gaps to move towards more sustainable processes

Lithium is a crucial element for the energy transition; therefore, the demand projections will increase drastically in the short and medium term. Almost 48% of the current Li production worldwide comes from salt lake brines sources, where the brine processing considers an evaporation ponds stage which losses around 90% of the water contained in brine to the atmosphere. This method causes concerns about the potential impact on salt lake water balance and biodiversity, promoting interest in new alternatives to replace the evaporative way. However, the tendencies, focus of studies, and holistic analysis of the potential impacts of these technologies still require further discussion. This work provides an overview of state-of-the-art technological tendencies of alternative processes to treat Li-rich brines based on bibliometrics, content analyses, and a literature review. Direct lithium extraction (DLE) processes have drawn the attention of researchers and technology companies due to their high Li extraction efficiency. Besides, recent works have started to study lithium brine concentration (LBC) methods, which can synergically complement the performance of DLE processes. However, any technological alternative should assess the impact on each salt lake in designing future processes. In this regard, the availability of public information about performance results of technological companies and lithium producers, overall assessment of processing options including carbon and water scarcity footprint, and studies evaluating the effect of returning spent brine into the salt lake are issues that need to be settled. Thus, future definitions and studies must consider a holistic analysis integrating DLE and LBC methods.