Environmental and life cycle assessment of lithium carbonate production from Chilean Atacama brines†

Abstract

The exponentially growing market for lithium-ion batteries (LIBs) is driving the development of more environmentally benign processes for producing lithium carbonate, a key precursor. 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 about evaporation rates from Atacama salars, the performance of the northern Chile electrical grid fuel mix and present waste management processes were analysed to establish the water balance, water footprint (WF), water scarcity footprint (WSF) and to estimate in Aspen Plus and Sphera the environmental performance of the battery-grade lithium carbonate production process. The results predicted significant environmental impacts associated with production of input chemicals such as sodium hydroxide (NaOH) and sodium carbonate (Na₂CO₃), as well as with energy conversion from the carbon intensive electrical supply in northern Chile. The waste dumps and surface impoundments required for the production process did 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 rates 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.