Extraction of lithium from oilfield waste-water brine

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Lithium extraction from brine is conventionally achieved by the removal of magnesium, calcium, and barium,which have similar chemical behaviors to lithium, followed by solar evaporation in a pond to concentrate andprecipitate lithium compounds. Although this approach benefits from a relatively low-cost and simpleoperation, evaporation of large volumes of water in cold regions such as Alberta is neither economicallyfeasible nor environmentally benign. In this project, we will investigate lithium extraction from brine waterusing unconventional approaches, predicated on the selective scavenging of lithium ions without resorting tosolar evaporation ponds. One of the few identified lithium extractants is tributyl phosphate (TBP), which hasbeen used widely in nuclear chemistry to process spent nuclear fuel. In our study, the first objective is to fullycharacterize the geochemistry of the brines. The second objective is to extract lithium directly from the brine byTBP using two approaches: (1) utilizing TBP as a solvent, followed by recycling TBP by stripping the lithiumfrom it, and (2) hybridizing TBP with organic particles and employing them in a sorption column to selectivelysequester lithium from the brine. The sorbent can be regenerated in a concentrated acid to efficiently desorb thelithium ions. Although there is ample literature surrounding TBP as extractant in nuclear waste treatment, thereare few studies dedicated to TBP as lithium scavenger, in most of which TBP is diluted in an organic solventand used as a solvent extractant. The results from our work could not only equip our industry partner with anew technique to address lithium extraction from brine but also open a new window into the research on theselective sequestering of lithium from brine.