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为实现高镁锂比盐湖卤水的锂镁分离,合成了一种新的锂离子吸附球形树脂。该树脂采用对锂离子有特定螯合作用的二苯并-14-冠-4为功能单元,并与有机磷酸酯形成对锂离子起协同作用的萃取体系,以聚氨酯为树脂骨架,通过悬浮聚合得到锂离子吸附球形树脂。悬浮聚合以二甲基硅油为分散介质、以粒度为300~400目的碳酸钙为稳定剂、n(羟甲基化产物)∶n(有机磷酯)∶n(甲苯二异氰酸酯)=1∶1∶28,以聚醚多元醇为交联剂、锂溶液为模板致孔剂,反应温度为80℃,时间为10 h,搅拌速度为280 r/min,得到粒度范围为55.36~76.33μm的球形树脂。热分析表明,树脂是均质的,具有较高的热稳定性。树脂经索氏抽提8 h的溶损率为1.5%,说明其在水中使用是稳定的。在pH 7、恒温振荡温度为25℃、振荡时间为4 h条件下,得到树脂对锂的最大吸附容量为0.609 9 mmol/g,其对锂镁选择性系数β=39;经过5次再生实验,其树脂饱和吸附容量仅下降1.8%,表明树脂可多次使用。
In order to realize the lithium-magnesium separation of high-Mg-Li salt brine, a new lithium-ion adsorption spherical resin was synthesized. The resin adopts a dibenzo-14-crown-4 which has a specific chelating action on lithium ions as a functional unit and forms an extraction system which cooperates with an organic phosphate to act on lithium ions. Polyurethane is used as a resin skeleton and polymerized by suspension polymerization Get lithium ion adsorption spherical resin. Suspension polymerization using dimethyl silicone oil as the dispersion medium, calcium carbonate particle size of 300 to 400 mesh as a stabilizer, n (methylolated product): n (organophospholipid): n (toluene diisocyanate) = 1: 1 : 28, polyether polyol as cross-linking agent, lithium solution as template porogen, the reaction temperature is 80 ℃, the time is 10 h, stirring speed is 280 r / min, the particle size range of 55.36 ~ 76.33μm spherical Resin. Thermal analysis shows that the resin is homogeneous and has high thermal stability. Soxhlet extraction of resin 8 h loss rate of 1.5%, indicating that its use in water is stable. The maximum adsorption capacity of lithium on resin was 0.609 9 mmol / g, the selectivity coefficient of lithium to magnesium was β = 39 under pH 7, constant temperature oscillation temperature of 25 ℃ and shaking time of 4 h. After five regeneration experiments , Its saturated resin adsorption capacity decreased only 1.8%, indicating that the resin can be used repeatedly.