磁性锂离子筛的制备及提锂性能研究

在Stober法的基础上采用二氧化硅对Fe_3O_4包覆钝化,使锂锰氧化物在二氧化硅界面生长,陈化、过滤、烘干、煅烧后生成Li_(1.6)Mn_(1.6)O_4@SiO_2@Fe_3O_4纳米锂离子筛前驱体。酸浸抽锂后得到磁性锂离子筛。SEM结合EDX测试表明,锂锰尖晶石相对均匀地包覆在钝化后的磁核表面,磁性离子筛的平均粒径为18.6nm。在配制的模拟卤水中,H_(1.6)Mn_(1.6)O_4对锂的平衡吸附量是8.78 mg/g,本文制备的H_(1.6)Mn_(1.6)O_4@SiO_2@Fe_3O_4对锂平衡吸附量可达6.01mg/g,除了Mg~(2+)平衡吸附量达到5.213 mg/g以外,其它离子的吸附量都在1.756mg/g以下,说明材料对Li~+的吸附有较好的选择性。用磁性锂离子筛开展反复吸附、脱附试验10次后,其对Li~+仍有良好的吸附效果,平衡吸附量稳定在5.1mg/g,锂解吸率在95%左右。磁性锂离子筛的饱和磁化强度为15.14emu/g,矫顽力为63.02G,可在外加磁场作用下实现与卤水的磁分离。

Preparation of Magnetic Lithium Ion-sieve and Its Lithium Uptaking

Fe3O4 was passivated by silica based on Stober method. Lithium manganese oxide grew at silica interface. Li1.6Mn1.6O4@SiO2@Fe3O4 nanometer lithium ion-sieve precursors were produced after aging, filtration, drying, and calcining. SEM and EDX tests show that lithium manganese spinel is relatively uniformly coated on surface of passivated magnetic core. Average particle size of magnetic ion-sieve is 18.6 nm. Equilibrium adsorption capacity of lithium H1.6Mn1.6O4 is 8.78 mg/g, and adsorption capacity of H1.6Mn1.6O4@SiO2@Fe3O4 prepared for this research is 6.01 mg/g in simulated brine. In addition to Mg2 equilibrium adsorption capacity of 5.213 mg/g, adsorption of other ions is 1.756 mg/g below, indicating that adsorption of Li to material has good selectivity. After repeated experiments with magnetic lithium ion sieves for 10 times, equilibrium adsorption capacity of Li is 5.1mg/g with desorption rate of lithium of about 95%. Magnetic lithium ion sieve has good magnetic properties with saturation magnetization of 15.14 emu/g and coercivity of 63.02 G, which can be separated from brine by magnetism separation under the applied magnetic field.