锂离子吸附球形树脂的合成及其性能研究

Synthesis and Properties of Lithium Ion Adsorption Spherical Resin

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 this work,a new kind of lithium ion adsorption spherical resin was synthesized.It was used to extract lithium ion from salt lake brine with high magnesia/lithium ratio.By using dibenzo-14-crown-4（DB14C4） as functional group for chelating lithium ion,the synergistic extraction system being formed with organic phosphorus together,adsorption resin was synthesized by means of suspension polymerization,using polyurethane as basic skeleton of the resin,and methyl silicone oil as dispersing medium,calcium carbonate（particle size is 300 ~ 400 mesh） as stabilizer,molar ratio of suspension polymerization of hydroxymethylation products,organophosphorus ester,toluene diisocyanate was 1 ∶1 ∶28,polyether glycol as crosslinking agent,lithium solution as template pyrogenic agent,reaction temperature being 80 ℃,reaction time being 10 h,stirring speed 280 r/min,the particle size range 55. 36 ~76. 33 μm of lithium ion adsorption spherical resin was obtained.Thermal analysis showed that the resin was homogeneous and had high thermal stability.Soluble loss rate was only 1. 5%. And it is stable using in water. The maximum adsorption capacity of the resin is 0. 609 9 mmol/g.The optimal condition is pH = 7,constant temperature T = 25 ℃,shock time t = 4 h.The lithium magnesium selective coefficient of resin is β = 39.The regeneration of the resin for saturated adsorption capacity decline was only 1. 8%,which shows the resin could be used repeatedly.