TY - JOUR A1 - Vogel, Christian A1 - Kohl, Anka A1 - Adam, Christian T1 - Spectroscopic investigation in the mid- and far-infrared regions of phosphorus fertilizers derived from thermochemically treated sewage sludge ash T2 - Applied spectroscopy N2 - Inorganic phosphorus and nitrogen-phosphorus-potassium (NPK) fertilizers based on phosphates from thermochemically treated sewage sludge ash were analyzed using mid-infrared (mid-IR) and far-infrared (FIR) spectroscopy. The different compounds present in the fertilizers were qualitatively determined with the help of recorded reference spectra of pure substances. Differentiation between various phosphates and other compounds such as sulfates, nitrates, and oxides was possible using combined interpretation of the mid-IR and FIR spectra. The results are in agreement with previous X-ray diffraction (XRD) measurements of the same samples. The main phosphate phases detected were NH4H2PO4, MgHPO4·3H2O, Mg3(PO4)2, Ca5(PO4)5Cl, CaHPO4·2H2O, Ca(H2-PO4)2·H2O, and AlPO4. Furthermore, K2SO4, NH4NO3, Fe2O3, and SiO2 were identified in the IR spectra. However, ammonium and sulfate compounds were only identified in the mid-IR region but were not detectable in the FIR region. PB - Society for Applied Spectroscopy CY - Frederick, Md. KW - Sewage sludge ash KW - Fertilizer KW - P-fertilizer KW - Phosphorus compounds KW - Mid-infrared spectroscopy KW - Far-infrared spectroscopy PY - 2011 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/23270 AN - OPUS4-23270 SN - 0003-7028 SN - 1943-3530 VL - 65 IS - 3 SP - 265 EP - 271 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany