溶剂萃取法净化萃余酸制备磷酸二氢钾工艺研究

Preparation of KH_2PO_4 by raffinate acid from solvent extraction purification process

湿法磷酸因含有多种杂质通常需要净化处理。溶剂萃取法是净化湿法磷酸的主要方法之一,其特点是溶剂回收容易且费用低,但磷酸回收率不高,萃余液带出的磷酸相对较多。对此,以氯化钾和以溶剂萃取法净化湿法磷酸的萃余酸为原料,利用正丁醇为萃取剂,回收萃余酸中的湿法磷酸制备磷酸二氢钾。该方法经济、简单,制备的磷酸二氢钾纯度较高,对促进磷酸二氢钾制备工业的发展具有一定意义。

Wet process phosphoric acid usually requires purification,because it contains a variety of impurities.Solvent ex- traction method is one of the main methods of purification of wet process phosphoric acid, which is characterized by easy and low-cost solvent recovery, but the recovery rate of phosphoric acid is not high and phosphoric acid content is relatively high in the raffinate.In this regard, potassium chloride and raffinate acid from the purification of wet process phosphoric acid by solvent extraction were used as the raw materials, the use of n-butanol as extraction solvent, and the wet process phosphoric acid in the raffinate acid is recovered by preparing the potassium dihydrogen phosphate.This method is economical, simple, and purity high in the preparation of potassium dihydrogen phosphate,which is significant for promoting the development of potassium dihydrogen phosphate industry.