层状吸附剂提锂过程研究

Extraction of lithium from solution with layered adsorbent

采用吸附热力学、动力学、离子选择性以及填充床吸附突破曲线等,研究了层状吸附剂对溶液中锂离子的吸附性能。分别用Langmuir和Freundlich等温模型对实验数据进行拟合发现,Langmuir吸附等温模型拟合度更高(0.996),说明吸附剂对锂离子的吸附更符合Langmuir型平衡分配曲线。从动力学曲线拟合结果可以看出,准二级动力学模型拟合平衡吸附容量与实验所得结果更为接近。选择性吸附实验表明,在其他金属阳离子如钠、钾、镁等离子共存下,吸附剂对锂离子有较高的吸附选择性。纯锂溶液填充床实验发现,流量增大使得填充床贯穿时间缩短,但同时贯穿吸附量及饱和吸附量减小,吸附剂床层利用率降低。模拟卤水填充床实验数据表明,层状吸附剂对锂离子有较好的吸附选择性,锂离子饱和吸附容量为4.01 g/L。

The adsorption properties of layered adsorbent to Li＋in aqueous solution were studied by adsorption thermodynamics,kinetics,ion selectivity and breakthrough curves of packed bed etc..Langmuir and Freundlich isotherm models were used to fit the experimental data.The results showed that Langmuir isotherm model was fitted to a higher degree（0.996）,indicating that the adsorption of Li＋was properly correlated with Langmuir model.According to the results of the kinetic curve fitting,the pseudo-second-order kinetic model was more correlated with experimental results.Selective adsorption experiments showed that the adsorption of Li＋was higher than that of other metal cations,such as Na~＋,K~＋ and Mg^（2＋）.Packed bed experiment showed,with the increase of flow rate,the breakthrough time of packed bed was shortened,but the breakthrough capacity and saturated adsorption capacity decreased.The experimental data of simulated brine packed bed showed that layered adsorbent had good adsorption selectivity and the saturated adsorption capacity to Li＋in brine was 4.01 g/L.