Study of impurities effect on the dielectric properties of ammonium phosphate fertilizer using the dielectric impedance spectroscopy

Ammonium phosphate fertilizers are obtained from neutralization reactions of phosphoric acid with ammonia. Several works were carried out to define and to control the impurities effect on the physicochemical properties of these fertilizers. However the description of these effects remains an area of disagreement among researchers. Among these studies, those were conducted to investigate the dielectric properties of certain phosphate materials, such as KH2PO4 and NH4H2PO4. Many of these crystal phases are isostructural to the paraelectric phase (EP), by cooling they exhibit a phase transition (PE) to a ferroelectric phase (FE), this usually para-ferroelectric transition occurs at low temperature. In this work our interest is, particularly, to study the impurities effect on the physical properties related to phase transitions in the fertilizer matrix.