Viability assessment of lithium recovery from unconventional saline water sources
Nathanial J. Cooper, Boreum Lee, Sohum K. Patel, Li Wang, Paul Westerhoff, Menachem Elimelech
Abstract
Lithium-ion batteries are becoming more ubiquitous, increasing lithium demand. Lithium carbonate, the most common form of industrial lithium, is primarily produced from lithium-rich brines concentrated using solar evaporation ponds. This extraction method is environmentally damaging and slow, taking a year or more to sufficiently concentrate. To meet the increasing demand, new technologies are being developed which can facilitate lithium recovery and shorten production timelines. This work examines two promising separations technologies, ion exchange resins due to their low cost and intercalation electrodes due to their high selectivity, and applies them to two potential alternative lithium sources — seawater reverse osmosis concentrate, and oil and gas produced water — to evaluate their efficacy. We develop process trains for each technology and analyze them using technoeconomic analysis and lifecycle assessment to determine economic and environmental feasibility. Further, technical improvements and process train modifications are examined to determine the impact on lithium carbonate cost. Our results show that currently ion exchange resins are the cheaper technology for recovering lithium, and that oil and gas produced water can produce lithium carbonate for as little as $14.96 kgLi 2 CO 3 −1 while recovering 34.3 % of lithium in solution, making it economically viable as a recovery option. Given sufficient technical improvements, intercalation electrode production costs for lithium carbonate may also be competitive. The preferred technology for minimizing the environmental impact is dependent on water source, but the ion exchange resin paired with oil and gas produced water has the lowest environmental impact overall, producing only 17.7 kgCO 2 -eq kgLi 2 CO 3 −1 .