锰系吸附剂对自贡地下卤水低品位锂的吸附性能研究

Study on Adsorption Performance of Manganese Based Adsorbent for Low Grade Lithium in Underground Brine from Zigong

通过静态、动态吸附和解吸试验研究锰系吸附剂对四川自贡地下卤水低品位Li^(+)的吸附性能。结果表明,锰系吸附剂对卤水中低品位Li^(+)的吸附容量随着pH值升高逐渐增大,且在pH值为7.0左右时锰的溶损最小;温度对吸附效果的影响较小,吸附剂在常温下便具有良好的吸附效果;随着时间的延长,吸附剂的吸附容量增大,在2 h时吸附达到平衡,吸附容量达到7.85 mg/g;吸附过程符合伪二级动力学模型和单分子层吸附的Langmuir等温吸附模型,且对Li^(+)有较好的吸附选择性和稳定性;以0.08 mol/L硫酸解吸2 h后,吸附剂的解吸率达到96%;在动态吸附过程中,不同流速下,在流出液体积达到40 BV之前,吸附剂的吸附效率较高,在70 BV时达到吸附平衡;在动态解吸过程中,解吸液Li^(+)浓度先增大再减小,可收集3~4 BV解吸液作为合格液可用于后续浓缩生产。

The adsorption performance of manganese based adsorbents for low-grade Li^(+) in Sichuan Zigong underground brine was studied by static and dynamic adsorption and desorption experiments.The results show that the adsorption capacity of the adsorbent for low-graded Li^(+) in brine increases with the increase of pH value,and the dissolution loss of manganese is the smallest when the pH value is about 7.The temperature has little effect on the adsorption effect,and the adsorbent has a good adsorption effect at room temperature.With the prolongation of time,the adsorption capacity increased,and the adsorption reached equilibrium at 2 h,and the adsorption capacity reached 7.85 mg/g;the adsorption process conforms to the pseudo-second-order kinetic model and the Langmuir isothermal adsorption model of monolayer adsorption,and has good adsorption selectivity and stability for Li^(+).After desorption with 0.08 mol/L sulfuric acid for 2 h,the desorption rate of the adsorbent reached 96%.In the dynamic adsorption process,the adsorption efficiency of the adsorbents at different flow rates were higher before effluent volume reached 40 BV,and the adsorbents reached the adsorption equilibrium at 70 BV.In the dynamic desorption process,the concentration of Li^(+) in the desorption solution increased first and then decreased,and 3~4 BV desorption solution could be collected as a qualified solution for subsequent concentration production.