TY - JOUR A1 - Vogel, Christian A1 - Adam, Christian A1 - Sekine, R. A1 - Schiller, T. A1 - Lipiec, E. A1 - McNaughton, D. T1 - Determination of phosphorus fertilizer soil reactions by Raman and synchrotron infrared microspectroscopy N2 - The reaction mechanisms of phosphate-bearing mineral phases from sewage sludge ash-based fertilizers in soil were determined by Raman and synchrotron infrared microspectroscopy. Different reaction mechanisms in wet soil were found for calcium and magnesium (pyro-) phosphates. Calcium orthophosphates were converted over time to hydroxyapatite. Conversely, different magnesium phosphates were transformed to trimagnesium phosphate. Since the magnesium phosphates are unable to form an apatite structure, the plant-available phosphorus remains in the soil, leading to better growth results observed in agricultural pot experiments. The pyrophosphates also reacted very differently. Calcium pyrophosphate is unreactive in soil. In contrast, magnesium pyrophosphate quickly formed plant-available dimagnesium phosphate. KW - Fertilizer KW - Phosphate-bearing mineral phases KW - Raman microspectroscopy KW - Sewage sludge ash KW - Soil KW - Synchrotron infrared microspectroscopy PY - 2013 U6 - https://doi.org/10.1366/13-07056 SN - 0003-7028 SN - 1943-3530 VL - 67 IS - 10 SP - 1165 EP - 1170 PB - Society for Applied Spectroscopy CY - Frederick, Md. AN - OPUS4-29268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Christian A1 - Adam, Christian A1 - Kappen, P. A1 - Schiller, T. A1 - Lipiec, E. A1 - McNaughton, D. T1 - Chemical state of chromium in sewage sludge ash based phosphorus-fertilisers N2 - Sewage sludge ash (SSA) based P-fertilisers were produced by thermochemical treatment of SSA with Cl-donors at approximately 1000 °C. During this thermochemical process heavy metals are separated as heavy metal chlorides via the gas phase. Chromium cannot be separated under normal conditions. The risk of the development of toxic Cr(VI) during the thermochemical process was investigated. X-ray Absorption Spectroscopy measurements showed that SSA and thermochemically treated SSA with CaCl2, MgCl2 and NaCl contain Cr(III) compounds only. In contrast, treating SSA with elevated quantities of Na2CO3, to enhance the plant-availability of the phosphate phases of the fertiliser, developed approximately 10–15% Cr(VI). Furthermore, Raman microspectroscopy showed that using Mg-carbonate reduces the risk of a Cr(VI) development during thermochemical treatment. Additionally, leaching tests showed that only a Cr–water solubility >10% is an indicator for Cr(VI) in SSA based P-fertilisers. KW - Chromium KW - Fertiliser KW - Sewage sludge ash KW - Raman microspectroscopy KW - X-ray absorption spectroscopy PY - 2014 U6 - https://doi.org/10.1016/j.chemosphere.2013.12.012 SN - 0045-6535 SN - 0366-7111 VL - 103 SP - 250 EP - 255 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-30062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -