湿法磷酸制取磷酸脲工艺优化及杂质行为研究

二水法生产的湿法磷酸中存在大量的阴离子和阳离子，这些离子很难在磷酸净化过程中除去。用湿法磷酸直接制取磷酸脲时，杂质离子会影响介稳区宽度，进而影响产品的产率和质量。通过改变原料配比、反应时间、反应温度、降温速度、结晶温度和搅拌速度等因素探索了湿法磷酸直接生产磷酸脲的最佳工艺条件，并分析湿法磷酸中存在 的SO42-、SiF62-、Fe3+、Al3+和Mg2+几种主要杂质离子对磷酸脲的产率和产品质量的影响。实验发现，保持一定量的SiF62-浓度有利于提高产品产率，但是其浓度不宜太高。SO42-、Fe3+、Al3+和Mg2+等会降低磷酸脲的产率，并且 Fe3+和Al3+对产率影响较大。

Urea phosphate production process optimization and effect of impurities on crystallization

There are a large number of anions and cations in the production of wet process phosphoric acid by DH process，which is difficult to remove out in the process of phosphoric acid purification.When synthesis of urea phosphate with the wet process phosphoric acid directly，these impurity ions affect the metastable zone width，and therefore affect the product yield and quality. Test by changing the ratio of raw materials，reaction time，reaction temperature，cooling rate，crystallization temperature，and stirring speed etc. to explore the optimum conditions for the production of urea phosphate.The influences of several main impurities， such as SO42-，SiF62-，Fe3+，Al3+，and Mg2+ in the phosphoric acid by wet process on the yield and quality of urea phosphate product were analyzed.In the experiments it was found that a certain amount of SiF62- concentration will help to improve production yield，but its concentration should not be too high. SO42-，Fe3+，Al3+，and Mg2+ will reduce the production yield of urea phosphate，especially，Fe3+ and Al3+ had a greater impact on the production yield.