湿法磷酸制备磷酸脲过程中会副产大量磷酸脲母液,母液含有金属杂质及五氧化二磷含量较高。采用溶剂萃取法回收磷酸脲母液中五氧化二磷制备工业级磷酸二氢铵（MAP）,分别考察了包括萃取、洗涤、中和、精制、结晶等工艺流程对产品收率及纯度的影响,确定了最佳工艺条件：萃取相比（有机相与水相体积比）=3:1,萃取时间为5 min,萃取温度为50 ℃,洗涤相比（有机相与洗涤剂体积比）=10:1,中和pH为4.5,复合酸性萃取剂PO8皂化率为20%,精制相比（萃取剂与水相体积比）=1:1,浓缩比为1.36,结晶温度为30 ℃。在该条件下制备的工业级MAP纯度可达99.45%,母液中五氧化二磷回收率为85.34%。该工艺对环境友好,原料中五氧化二磷回收率高,具有较高的经济效益。

In the process of preparing urea phosphate by wet process phosphoric acid,a large amount of urea phosphate moth-er liquor was by-produced,in which metal impurities and P₂O₅ were relatively high. Industrial grade MAP was prepared by us-ing the P₂O₅ recovered from the urea phosphate mother liquor through solvent extraction method.The effects of technological process including extraction,washing,neutralization,refining and crystallization on the yield and purity of product were in-vestigated.The optimum process conditions were confirmed: the extraction ratio（volume ratio of organic phase to aqueous phase）was 3:1,the extraction time was 5 min,the extraction temperature was 50 ℃,the washing ratio（volume ratio of organic phase to detergent）was 10:1,the neutralization pH=4.5,the saponification rate of compound acid extractant PO8 was 20%,the refining ratio（volume ratio of extract phase to aqueous phase） was 1:1,the concentration ratio was 1.36 and the crystalliza-tion temperature was 30 ℃.Under the optimum condition,industrial grade MAP with the purity of 99.45% was obtained and the P₂O₅ recovery rate in the mother liquor was 85.34%.The method had high economic benefits as its process was environmentally friendly,and the P₂O₅ recovery rate of raw materials and economic benefits were high.