工业磷酸-尿素缩聚法制备低聚磷酸铵工艺研究

Preparation of ammonium polyphosphate with low polymeric degree through industrial phosphoric acid-urea polycondensation process

以工业磷酸与尿素为原料,采用脱水聚合法制备低聚合度水溶性聚磷酸铵,用控制聚合反应时间、聚合温度和原料配比来探讨聚磷酸铵产品的性能。分别采用重量法测定产品的磷含量、蒸馏法测定产品氮含量、端基滴定法来确定产品平均聚合度,并通过XRD分析验证聚磷酸铵的晶型。实验结果表明:在最佳工艺条件下[原料配比(工业磷酸与尿素物质的量比)为1∶0.9、聚合反应时间为1.5 h、聚合反应温度为150℃,所得聚磷酸铵产品的五氧化二磷质量分数能达到62.1%、氮质量分数能达到14.6%、平均聚合度低于20、水溶性良好,完全符合农用聚磷酸铵(Q/CQS 02—2018)优等产品应用标准。

Low-polymerization water-soluble ammonium polyphosphate was prepared by dehydration polymerization method using industrial phosphoric acid and urea as raw materials.The effect of reaction time,reaction temperature,and ratio of ingredients on the performance of ammonium polyphosphate product was discussed by univariate method.The phosphorus content of the product was measured by the gravimetric method,and the nitrogen content of the product was measured by the distillation method.The average degree of polymerization of the product was determined by end-group titration,and the crystal shape of the APP product was verified by XRD.The results showed that the phosphorus content of the APP product could reach 62.1%on the optimum conditions:raw material ratio(the amount-of-substance ratio of phosphoric acid to urea)was 1∶0.9,reaction time was 1.5 h,and reaction temperature was 150℃.The content could reach 14.6%,the average degree of polymerization was less than 20,and the water solubility was well.All of the prepared APP products completely met the requirements for agricultural ammonium polyphosphate standard.