EXTRACTION OF LITHIUM FROM BASINAL BRINES

Demand for lithium use is projected to grow two- or three-fold in the coming decade, due primarily to increased manufacturing of lithium-ion batteries for use in electric vehicles and grid storage. At present most lithium is sourced from hard rock mines or from salars in South America; however, alternative sources will be needed to meet the coming supply gap. Among non-traditional sources are basinal brines typically associated with petroleum production (petrobrines) or geothermal energy. While these brines contain lithium concentrations that can be more than an order of magnitude lower than salars, the vast emplaced brine volumes make them a resource that could supply a significant fraction of the global lithium needs. However, low-cost, efficient, and robust extraction, concentration and purification methods are needed to ensure that low lithium-bearing brines can become an economic resource.

This study investigated the use of manganese-based ion-exchange sorbents to recover lithium from field-collected petrobrines of the Western Canadian Sedimentary Basin. Sorbents were characterized using techniques including synchrotron-based X-ray absorption spectroscopy (XAS), transmission electron microscopy coupled to electron energy loss spectroscopy (TEM-EELS), and X-ray photoelectron spectroscopy (XPS) to understand changes in structure and Mn valence state before and after sorbent use. The results reveal that both aqueous sulfide species and dissolved organic compounds in the brine can cause reduction of Mn(IV) in the sorbent, ultimately resulting in sorbent loss due to the release of soluble Mn²⁺ into the surrounding solution. Finally, an economic case is made for a sorbent that is optimized to minimize manganese loss while still retaining sufficient lithium uptake.