膜分散萃取净化湿法磷酸

Research on purifying wet-process phosphoric acid by membrane dispersion extraction

采用膜分散方法研究了湿法磷酸的萃取特性,以水/磷酸/TBP+煤油为实验体系,以不同名义孔径的不锈钢纤维烧结膜为分散介质,在自制的萃取器中研究了流量、膜孔径、煤油含量、相比、磷酸浓度、萃取室体积和停留时间对单级萃取效率的影响,找出适宜操作条件。实验结果表明,流量增加,单级萃取效率呈现先增加后降低的趋势;减小膜孔名义直径,增加磷酸浓度,单级效率升高;适度增加萃取室体积,延长停留时间,对萃取有利;萃取剂中混加煤油,萃取效率下降。在分散相流量为1000 mL/min、采用10μm的不锈钢烧结膜、煤油体积分数为20%、相比1∶1、磷酸质量分数在30%～70%、萃取室体积为30 mL的情况下,单级效率可以达到96%。

The membrane dispersion extraction process was used to purify wet-process phosphoric acid with stainless steel fiber sintered membrane as dispersion media.The system of water/phosphoric acid/ TBP ＋ kerosene was used to study the effects of flow rate,membrane diameter,kerosene content,phase ratio,phosphate content and extraction cell volume and residence time on the extraction.When flow rate increased,extraction efficiency increased first and then decreased.,When pore diameter decreased and phosphoric acid concentration of water increased,extraction efficiency increased.When extraction cell volume was enlarged and residence time was increased,extraction efficiency increased.With 10 μm stainless steel fiber sintered membrane,at dispersed phase flow rate of 1000 mL/min,kerosene volume fraction of 20%,phase ratio of 1∶1,phosphoric acid content of 30%-70%,extraction cell volume of 30 mL,single-stage efficiency could reach 96%.