锂离子筛前驱体Li_4Mn_5O_(12)的制备及性能研究

Synthesis and Properties of Lithium Ion-sieve Precursor Li_4Mn_5O_(12)

吸附法是目前从低锂浓度的盐湖卤水中提取锂的最有前途的方法。采用EDTA-柠檬酸络合法制备了Li4Mn5O12前驱体,经酸浸脱锂后得到对Li+具有特殊选择性的锰氧化物锂离子筛。通过热重、XRD、SEM、FT-IR、化学组成、吸附动力学及共存金属离子的分配系数等手段对样品的晶相结构和Li+选择性吸附性能进行了研究。结果表明:煅烧时间对Li4Mn5O12前驱体生成有较大影响,由400℃煅烧24 h所得的前驱体几乎为纯相的Li4Mn5O12化合物,经酸浸脱锂后的离子筛仍保持着与前驱体相同的尖晶石结构;前驱体Li4Mn5O12和离子筛MnO2均为200 nm左右的球状颗粒;离子筛的最大吸附容量为43.1 mg/g,并具有较好的Li+选择性。

Adsorption method is the most promising method for extraction of lithium from salt lakes.A new kind of MnO2 ion-sieves with high Li＋ selective adsorption property were synthesized.Spinel-type Li4Mn5O12 precursors were synthesized by EDTA-citrate complexing method using LiNO3 and Mn（NO3）2.4H2O as starting materials.MnO2 ion-sieves with Li＋ selective adsorption property were prepared by the acid treatment process to extract Li＋ from the spinel Li4Mn5O12 precursors.As-prepared samples were characterized by thermo gravimetric,XRD,SEM,FT-IR and Li＋ selective adsorption measurements,respectively.The results show that calcination time has a considerable effect on the structure and composition of precursors.The precursor calcined at 400℃ for 24 h has a pure phase of Li4Mn5O12.Final MnO2ion-sieve and Li4Mn5O12precursor are about 200 nm spherical pellets and have the same structure of spinel.The maximum adsorption capacity of ion-sieve is about 43.1 mg/g and has the good selection for Li＋.