Ca2+-Mg2+-Zn2+体系在水溶性聚磷酸铵溶液中螯合规律的研究

近年来,水溶性聚磷酸铵在液体肥料和复合肥料的领域受到了广泛的关注,并在发达国家中得到了大面积的推广及应用。在pH值为5.5~8.0、温度为278.15 K~323.15 K的条件下,本文采用滴定法研究Ca_²⁺-Mg_²⁺-Zn_²⁺体系在聚磷酸铵溶液中的螯合规律。实验结果表明：相同质量分数的聚磷酸铵溶液对金属离子的螯合量会随着体系中Ca_²⁺、Mg_²⁺、Zn_²⁺的摩尔浓度的变化而变化；随着温度的升高而逐渐降低；随着pH的增加而逐渐增加；随着聚合度的升高而逐渐增加。采用傅里叶红外光谱对聚磷酸铵和A₁B₃C₃体系的螯合物进行表征。

Study on the chelation law of Ca2+-Mg2+-Zn2+ system in water-soluble ammonium polyphosphate solution

In recent years, water-soluble ammonium polyphosphate has been widely concerned in the field of liquid fertilizer and compound fertilizer, and has been widely promoted and used in developed countries. The chelation law of Ca_²⁺-Mg_²⁺-Zn_²⁺ system in ammonium polyphosphate solution was researched by titration method at temperatures ranging from 278.15 to 323.15 K and at pH value ranging from 5.5 to 8.0. The results showed that the chelating amount of the same mass fraction of ammonium polyphosphates to metal ions would change with the change of the molar concentration of Ca_²⁺, Mg_²⁺, Zn_²⁺ in the system. The chelating amount of ammonium polyphosphate decreased with the increase of temperature and gradually increased with the increase of pH value. The chelating amount gradually increased with the increase of degree of polymerization. The ammonium polyphosphate and the chelates of A₁B₃C₃ system were characterized by Fourier transform infrared spectroscopy.