磷酸的溶剂萃取法净化

在全面调研国内外现有的湿法磷酸净化技术的基础上，实验比较了不同萃取剂(正丁醇、TBP、异丁醇和异戊醇)对于磷酸萃取的效果，结果表明，正丁醇对磷酸的萃取效果最好，温度的提高会使磷酸在两相的分配系数略有下降. 溶剂萃取磷酸主要以分子形式进行，因此无机强酸的加入有利于提高磷酸在两相的分配. 比较了正丁醇萃取纯磷酸和粗磷酸的差别，分析了其原因. 正丁醇对金属离子几乎没有萃取效果，因此，溶剂法可以作为一种有效的净化磷酸的方法.

Purification of Phosphoric Acid by Solvent Extraction

A study of purification of Chinese WPA by solvent extraction was carried out. The effect of temperature on distribution coefficient was investigated and the mechanism of extraction was discussed. The experimental results show that n-butanol has the highest capacity to extract phosphoric acid. With the increase of temperature, the distribution coefficient is found to decrease slightly. The study of extraction mechanism indicates that phosphoric acid is extracted in the form of neutral molecules. Accordingly, other stronger acids such as HCl added to the initial solution will be beneficial to the recovery of phosphoric acid. The fact that the metal ions in WPA are not extracted into the solvent makes out that the solvent extraction is one of the best methods to purify WPA.