Li4Mn5O12的改进合成及其在卤水中的选择性提锂性能

Improved Synthesis of Li4Mn5O12 and its Selective Extraction of Lithium from Brine

中文关键词:  盐湖卤水提锂  锂离子筛  吸附剂  选择性  稳定性

英文关键词:Extraction of lithium from salt lake brine  lithium ion screen  adsorbents  selectivity  stability

中文摘要:

      采用溶胶凝胶法，以乙酸锂、乙酸锰为原料，以柠檬酸为络合剂，并引入螯合剂乙二醇改善凝胶性质，同时对合成条件进行优化，制备出了锂离子筛前驱体Li4Mn5O12，酸洗后得到锂离子筛H4Mn5O12。采用XRD、TG-DTA、FTIR、SEM、XPS等手段对不同阶段的H4Mn5O12的结构特性进行研究、并利用吸附动力学、卤水中共存离子的分配系数及分离因子等分析方法对H4Mn5O12对卤水中Li+的选择分离性能进行研究。结果表明所制备的H4Mn5O12锂离子筛对盐湖卤水中的Li+具有优异的选择分离性能，在镁锂比为86左右的青海大柴旦盐湖的初始锂吸附容量达到36.80 mg/g，锰损率仅为0.71 %。H4Mn5O12在卤水中对Li+的吸附符合伪二级动力学模型，属于化学吸附。经过10次的吸附解吸循环实验，吸附容量仍有26.62 mg/g，锰损率为0.79 %，循环稳定性能优异，为高镁锂比盐湖锂吸附材料的研究提供了一定的思路。

英文摘要:

      Using lithium acetate and manganese acetate as raw materials, citric acid as complexing agent, ethylene glycol as dispersant and stabilizer, the precursor of Li4Mn5O12 lithium ion screen was prepared by sol-gel method. XRD, TG-DTA, FTIR, SEM, XPS, adsorption kinetics, partition coefficient and separation factor of coexisting ions in brine were used to study the structure of H4Mn5O12 lithium ion screen at different stages and its selective separation performance for Li+ in brine. The results show that the prepared H4Mn5O12 lithium ion screen has excellent selectivity and separation performance for Li+ in salt lake brine. The initial lithium adsorption capacity reaches 36.80mg/g and theDissolution loss rate of Mn2+ is only 0.71% in Daqaidan Salt Lake of Qinghai Province, where the MG-lithium ratio is about 86. The adsorption of Li+ by H4Mn5O12 in brine conforms to the pseudo-second-order kinetic model, which belongs to chemisorption. After 10 times of adsorption analysis cycle experiments, the adsorption capacity is still 26.62mg/g, and the Dissolution loss rate of Mn2+ is 0.79%, which has good cyclic stability, and provides a certain idea for the research of lithium adsorption materials in salt lakes with high magnesia-lithium ratio.