Assessment of environmental impacts of lithium hydroxide production via soda leaching route

Lithium is in a key role in the green energy transition and is listed as a critical raw material by the European Commission. Most importantly, lithium is used in lithium-ion battery (LiB) technologies, which are currently the most important battery chemistry applied in consumer electronics, battery electric vehicles and stationary battery energy storage systems. The amount of such applications is only expected to increase substantially in the future. Regardless of recent actions in lithium recy-cling, increase in lithium primary production is required, and it will still dominate lithium supply over the coming decades. Thus, guaranteeing a reliable and environmentally friendly production of lithium products for the battery industry is crucially important.
Lithium hydroxide monohydrate (LiOH·H2O) is a commonly used substrate in high-nickel LiB cathode manufacturing. Primary lithium is produced mainly from salar brines and spodumene ores, the latter of which are increasingly exploited due to growing lithium demand. However, the pro-cesses for extracting lithium from hard rock ores are more complex than those in brine treatment. The more conventional route applies sulfuric acid roasting and caustic conversion leaching, whereas more novel hydrometallurgical routes use alkaline leaching, which also enables the direct recovery of battery grade LiOH∙H2O. The environmental impacts of lithium production processes need to be assessed to ensure minimal environmental burden from LiB manufacturing.
This work evaluates the environmental impacts of LiOH·H2O production via a soda leaching process by applying a gate-to-gate life cycle assessment (LCA). The process consists of pressure leaching with soda, conversion leaching with lime, and vacuum crystallization of the product. The process was modelled as a flowsheet simulation to produce a life cycle inventory (LCI), and the environ-mental impacts were calculated using this data. It was found that chemicals, such as soda ash and quicklime, together with heat and electricity production are the largest contributors in most envi-ronmental impact categories. Choosing more environmentally friendly sources for these inputs would make lithium production footprints smaller in LiB manufacturing.