HEH[EHP]酸性络合萃取剂固体皂化性能研究

Study on Saponification of P_(507)(HEH/EHP) with Solid Saponifiers

为减少稀土萃取分离废水的处理量,达到节约生产成本的目的,拟寻找出合适的固体皂化剂代替现有的液体皂化技术。对2-乙基己基膦酸单2-乙基己基酯(简称HEH[EHP]或P_(507))为代表的酸性络合萃取剂进行了一系列固体皂化试验,试验结果表明,固体皂化剂MgO与P_(507)完全反应所需的时间最短,为2小时,固体皂化剂NaHCO_3与P_(507)不能完全反应;固体皂化剂MgO、NaHCO_3、Na_2CO_3与P_(507)反应后有机相呈浑浊状态,萃取易发生乳化现象。KOH和K_2CO_3混合固体皂化剂的加入比例和皂化反应温度对皂化性能影响较大,随着KOH百分含量的增加,皂化时间逐渐减少,且在KOH含量为60%时,下降幅度最大;随着反应温度的升高,反应时间逐渐减少;为考察其皂化机理和有机相的萃取性能,对皂化有机相进行了红外光谱分析和饱和萃取容量实验。发现其皂化及萃取机理属于阳离子交换,萃取过程无乳化现象发生,能够达到理论的饱和萃取量。

This paper intends to find out the suitable solid saponification agent to replace the existing liquid saponification technology to reduce wastewater emissions of rare earth smelting industry and save the cost of production. A series of solid saponification tests were carried out on the acid complex extraction agent, 2-ethylhexylphosphoric acid mono-2-ethylhexyl ester. The experimental results show that the reaction between solid saponifier magnesium oxide and Ps07 took the shortest time, about 2 hours. Solid saponifier sodium bicarbonate did not fully react with P507 ; Sotid saponifier such as magnesium oxide, sodium bi- carbonate, or sodium carbonate, reacting with P5o7, caused the organic phase to become turbid. Ratio of potassium hydroxide to potassium carbonate and saponification reaction temperature had a greater influence on the performance. With the increase of potassium hydroxide amount, saponification time gradually decreased. When the potassium hydroxide content was 60%, the largest decline came. With the increase of reaction temperature, reaction time gradually reducd. In order to study the mechanism of the extraction of organic phase and the extraction performance of organic phase, the infrared spectrum analysis and saturation extraction capacity of organic phase were studied. Experiment shows that the mechanism of the extraction belongs to cation exchang. The extraction process had no emulsification phenomenon and could reach the theoretical saturation value.