231-1 Dolomite filtration of lithium and cobalt from petroleum produced water

Session: Critical Mineral Resources and Recovery in the Americas: Emerging Methods in Exploration and Sustainable Extraction (Posters)

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Produced water (PW) from oil and gas reservoirs poses environmental and technical challenges due to their high salinity and the presence of toxic metals. However, PW from certain reservoirs also contains minable amount of critical metals such as lithium (Li) and cobalt (Co). Building on previous findings that demonstrated dolomite’s superior capacity to recover critical (Li, and Co) and toxic metals (e.g., Ba, Sr, Cd, Pb) from PW, this study investigates the feasibility and mechanisms of recovering critical metals specifically Li using dolomite filtration and the role of competing ions. To address this gap, a series of column-flow (filtration) experiments were conducted using synthetic PW of varying compositions and dolomite grain filters, designed to explore how pH and competing ions influence metal removal through sorption and precipitation. Aqueous samples were collected at the end of each filtration cycle and analyzed using ICP-OES to monitor changes in metal concentrations. Dolomite grains were also sampled from different sections of the filter (top, middle, and bottom) and analyzed using SEM-EDS and XRD to detect surface-bound metals and identify mineral precipitates. Additionally, X-ray Absorption Spectroscopy (XAS) spectra were employed to distinguish between sorbed and precipitated metal species on the dolomite surface. Preliminary XAS results indicate that under low pH conditions, metal removal was dominated by precipitation reactions forming carbonate minerals, whereas at higher pH, sorption became the dominant mechanism. SEM-EDS mapping confirmed the accumulation of metal-rich layers on dolomite grains, while XRD spectra identified the formation of mineral phases including zabuyelite  (Li₂CO₃), spherocobaltite (CoCO₃), and other mixed-metal carbonates. These findings suggest that dolomite filtration, driven by pH-dependent sorption and precipitation reactions, is a promising low-cost and sustainable method for the simultaneous removal of both divalent toxic metals and monovalent critical metals such as Li and Co from PW.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6475

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