The effect of composition on chemical durability of phophate glass fertilizers

Abstract

Phosphate glassy fertilizers are the new type of advanced and controlled released fertilizer, whose glassy matrixes consist of macroelements (K, P, Mg, Ca) most useful for plants and microelements (Fe, Cu, Zn, Mn) which are important to the growth and development of plants. The flexibility of glasses enables the variation of their composition and properties over a wide range. The dissolution behavior of glasses from the P2O5-SiO2-K2O-CaO-MgO system doped with various microelements in bidistilled water and the 2% aqueous solution of citric acid under static conditions was studied. The leaching tests were performed with glass powder samples (0.3–0.65 mm) at T=37 °C for periods up to 480 h. The samples mass loss, the changes of pH, as well as the concentration of elements in solution were determined.