SPECTROSCOPIC STUDIES OF Mn[O.sub.2] AND Si[O.sub.2] CONTAINING SOIL-ACTIVE PHOSPHATE GLASSES

• Published in: Journal of applied spectroscopy Vol. 83; no. 6; pp. 951 - 958
• Main Authors: Szumera, M, Lagowska, B
• Format: Journal Article
• Language: English
• Published: Springer 01-01-2017
• Subjects: Analysis; Fertilizers; Phosphates; Raman spectroscopy; Silicates
• ISSN: 0021-9037; 1573-8647
• DOI: 10.1007/s10812-017-0389-3

FT-IR and Raman spectra were measured and structurally interpreted for glasses of the 41[P.sub.2][O.sub.5] x 8Si[O.sub.2] x 6[K.sub.2]O x (26 - x) MgO x (19 - y)CaO x (x+y) Mn[O.sub.2] system where 0 [less than or equal to] x+y [less than or equal to] 40 mol.%, acting as slow-release fertilizers. It was shown that increasing the amount of Mn[O.sub.2] in the structure of the investigated glasses causes their gradual depolymerization, as is particularly apparent in the case of the phospho-oxygen subnetwork. Spectroscopic methods, on the other hand, showed no influence of manganese ions on the silicate subnetwork. Research on the chemical activity of the analyzed glasses conducted under conditions simulating a natural soil environment showed their low solubility with a simultaneous gradual increase in solubility occurring with an increasing number of manganese ions in the glass composition. It was found that this behavior resulted from the formation of less chemically stable bonds of the P-O- [Mn.sup.2+] type, as compared with bonds of the P-O-[Ca.sup.2+] and P-O-[Mg.sup.2+] types. This is consistent with the depolymerizing influence of manganese ions on the analyzed vitreous structure as shown by the FT-IR and Raman spectroscopy and, thus, its weakening.