Environmental and Life Cycle Assessment of Lithium Carbonate Production from Chilean Atacama Brines

Abstract

The increasing need for lithium(I), driven by the growing market for lithium-ion batteries (LIB) due to the push for Net Zero carbon society and cleaner energy sources, requires the environmentally benign manufacturing of lithium carbonate. Extracting lithium(I) from brine is a cost-effective method, particularly in the Lithium Triangle in South America, including the Atacama Desert in Chile. Life cycle assessment (LCA) was used to assess the environmental impacts of lithium(I) production by establishing a comprehensive life cycle inventory (LCI) with data from modelling, literature, technical reports and the Ecoinvent database. Information pertaining to evaporation rates from Atacama salars, the northern Chile electrical grid mix performance and present waste management processes were analysed to establish the water balance, water footprint (WF) and water scarcity footprint (WSF) and estimate the battery-grade lithium carbonate production process performance in Aspen Plus. The results predict significant environmental impacts associated with production of chemicals such as sodium hydroxide (NaOH) and sodium carbonate (Na₂CO₃), as well as with energy conversion from the carbon intensive electricity supply in northern Chile. The waste dumps and surface impoundments required for the production process do not result in significant leachate infiltration, although considerable land areas are occupied. The modelling and analysis results highlighted the importance of accurate brine evaporation rates on the process water balance estimation and on the conventional manufacturing process emissions; insufficient evaporation increased the water footprint of chemical production processes. The water resource stress in the arid Atacama region was evident from predicted water balances, WFs and WSFs, emphasising the necessity to innovate less time-consuming and water-conserving processes to increase sustainability.