From Waste to Value: Techno-Economic Analyses of Lithium Extraction from Oilfield Brine

Abstract This study presents an integrated strategy for lithium recovery from oilfield brines, combining targeted pre-treatment and continuous extraction using sieve-loaded polymeric foam membranes. Initial brine characterisation identified key interfering cations, guiding the development of an effective purification sequence involving activated carbon, reverse osmosis, and alkali-treated zeolites. Sodium-activated zeolites, particularly at high Na⁺ concentrations, demonstrated enhanced selectivity toward divalent ions, as confirmed by structure characterisation analysis. Foam membranes, synthesised with high porosity and permeability, achieved lithium adsorption capacities up to 42 mg/g with strong selectivity (α > 25) over competing ions. The system-maintained performance across multiple cycles with minimal material loss. Comparative testing on Buchan, Alberta, and Smackover brines highlighted the influence of Mg/Li ratios and lithium grade on recovery efficiency and saturation time. The techno-economic analysis revealed strong feasibility in high-concentration brines, with IRR values up to 47% and payback periods under 6 years. These results demonstrate the viability of foam-based continuous extraction as a modular, scalable solution for lithium recovery from complex brine matrices.