He Lihua, Xu Wenhua, Song Yunfeng, Luo Yunze, Liu Xuheng, Zhao Zhongwei
School of Metallurgy and Environment Central South University Changsha Hunan 410083 P. R. China.
Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 P. R. China.
Glob Chall. 2018 Jan 15;2(2):1700079. doi: 10.1002/gch2.201700079. eCollection 2018 Feb 9.
Lithium extraction from high Mg/Li ratio brine is a key technical problem in the world. Based on the principle of rocking-chair lithium-ion batteries, cathode material LiFePO is applied to extract lithium from brine, and a novel lithium-ion battery system of LiFePO | NaCl solution | anion-exchange membrane | brine | FePO is constructed. In this method, Li is selectively absorbed from the brine by FePO (Li + e + FePO = LiFePO); meanwhile, Li is desorbed from LiFePO (LiFePO - e = Li + FePO) and enriched efficiently. To treat a raw brine solution, the Mg/Li ratio decreases from the initial 134.4 in the brine to 1.2 in the obtained anolyte and 83% lithium is extracted. For the treatment of an old brine solution, the Mg/Li ratio decreases from the initial 48.4 in the brine to 0.5 and the concentration of lithium in the anolyte is accumulated about six times (from the initial 0.51 g L in the brine to 3.2 g L in the anolyte), with the absorption capacity of about 25 mg (Li) g (LiFePO). Additionally, it displays a great perspective on the application in light of its high selectively, good cycling performance, effective lithium enrichment, environmental friendliness, low cost, and avoidance of poisonous organic reagents and harmful acid or oxidant.
从高镁锂比卤水中提取锂是全球的一个关键技术问题。基于摇椅式锂离子电池的原理，将正极材料磷酸铁锂应用于从卤水中提取锂，并构建了一种新型的磷酸铁锂|氯化钠溶液|阴离子交换膜|卤水|磷酸铁的锂离子电池体系。在该方法中，磷酸铁从卤水中选择性地吸收锂（Li + e + FePO = LiFePO）；同时，锂从磷酸铁锂中脱附（LiFePO - e = Li + FePO）并有效富集。处理原卤水时，镁锂比从卤水中初始的134.4降至所得阳极电解液中的1.2，锂提取率为83%。处理老卤水时，镁锂比从卤水中初始的48.4降至0.5，阳极电解液中锂的浓度累积约6倍（从卤水中初始的0.51 g/L升至阳极电解液中的3.2 g/L），吸附容量约为25 mg(Li)/g(LiFePO)。此外，鉴于其高选择性、良好的循环性能、有效的锂富集、环境友好、低成本以及避免使用有毒有机试剂和有害酸或氧化剂，该方法在应用方面展现出巨大的前景。
