全水溶聚磷酸铵-稀土缓释肥的研制及其对蔬菜的施用效果

Development of Fully Water-soluble Ammonium Polyphosphate-rare Earth Slow-release Fertilizer and Its Application Effect to Vegetables

为研发新型全水溶聚磷酸铵−稀土缓释肥的合成方法及其对蔬菜的施用效果,使用聚合法合成低聚合度聚磷酸铵,通过控制聚合反应温度和原料配比,研究不同条件下聚磷酸铵的聚合度、水溶性、养分含量和pH变化。在此基础上通过控制反应条件,探究聚磷酸铵溶液对稀土金属镧和铈的螯合情况,并进一步利用制备的聚磷酸铵和聚磷酸铵−稀土肥进行田间肥效实验。结果表明,当85%磷酸与尿素摩尔比为1∶1.5、反应时间20 min、反应温度140℃时,合成的聚磷酸铵平均聚合度达到3.01,P_(2)O_(5)含量48.07%、含氮量26.38%,水溶性1.92 g·mL^(-1)。聚磷酸铵水溶液在50℃下使用超声方式溶解,螯合稀土金属镧和铈的含量分别达到541.0和757.4 mg·kg^(-1)。田间肥效实验表明,聚磷酸铵及聚磷酸铵−稀土肥对大白菜、茄子和番茄生长具有良好的促进作用。聚磷酸铵-稀土缓释肥是一类新型化肥,为实现化肥“减量增效”目标提供新的肥料品种。

To study the synthesis method of a new water-soluble ammonium polyphosphate-rare earth slow-release fertilizer and its application effect on vegetables,the polymerization method was used to synthesize ammonium polyphosphate with low polymerization degree. By controlling the polymerization temperature and the ratio of raw materials,the polymerization degree,water solubility,nutrient content and pH of ammonium polyphosphate under different conditions were determined. On this basis, by controlling the dissolution method and dissolution temperature,the chelation of the rare earth metal lanthanum and cerium by the ammonium polyphosphate solution was explored. The fertilizer efficiencies of prepared ammonium polyphosphate and ammonium polyphosphate rare earth fertilizers were tested in field. The results showed that the average polymerization degree,contents of phosphorus pentoxide and nitrogen,and the water solubility of ammonium polyphosphate were 3.01,48.07%,26.38% and 1.92 g·mL^(-1),respectively,according to the procedure with 1∶1.5 of 85% phosphoric acid to urea,reaction time 20 min and reaction temperature 140 ℃. When ammonium polyphosphate aqueous solution was dissolved by ultrasonic at 50 ℃,the contents of chelated rare earth metal lanthanum and cerium reached to 541.0 and 757.4 mg·kg^(-1),respectively. Fertilizer efficiency experiments in field showed that ammonium polyphosphate and ammonium polyphosphate rare earth fertilizers had significant effects on promoting the growths of Chinese cabbage,eggplant and tomato,which provided new fertilizer varieties for realizing“reduction and efficiency increase”fertilizer goal.