Extraction of lithium from oilfield waste-water brine

从卤水中提取锂通常是通过去除镁、钙和钡来实现的，这些元素的化学行为与锂相似，然后在池塘中进行太阳能蒸发，以浓缩和沉淀锂化合物。虽然这种方法受益于相对较低的成本和简单的操作，但在艾伯塔省等寒冷地区蒸发大量水在经济上既不可行，也不利于环境。在这个项目中，我们将研究用非常规方法从卤水中提取锂，这种方法的基础是选择性地清除锂离子，而不是求助于太阳蒸发池。磷酸三丁酯(TBP)是为数不多的锂萃取剂之一，它在核化学中被广泛用于处理乏核燃料。在我们的研究中，第一个目标是全面描述卤水的地球化学性质。第二个目标是用TBP直接从卤水中提取锂，采用两种方法：(1)利用TBP作为溶剂，然后通过反萃取锂来回收TBP；(2)将TBP与有机颗粒杂交，并将它们用于吸附塔中，选择性地从卤水中分离锂。该吸附剂可以在浓酸中再生，从而有效地解吸锂离子。虽然关于TBP作为核废料处理萃取剂的文献很多，但很少有关于TBP作为锂清除剂的研究，其中大多数是将TBP在有机溶剂中稀释并用作溶剂萃取剂。我们的工作结果不仅可以为我们的行业合作伙伴提供从卤水中提取锂的新技术，而且还可以为从卤水中选择性地分离锂的研究打开一扇新的窗口。

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.