TY - JOUR A1 - Lutz, W. A1 - Kurzhals, R. A1 - Sauerbeck, S. A1 - Toufar, H. A1 - Buhl, J.-C. A1 - Gesing, T. A1 - Altenburg, Wolfgang A1 - Jäger, Christian T1 - Hydrothermal stability of zeolite SAPO-11 N2 - The hydrothermal stability of SAPO-11 was studied in water of autogenous pressure as function of the temperature. SAPO-11 remained crystalline up to 190 °C. Thereby, it was observed, parent as well as hydrothermally treated samples showed similarities to the isotypic structure of zeolite AlPO-11 called here AELdry. After fully hydration of the samples, AELdry changed completely into a hydrated AELwet structure of another framework symmetry. The transition from calcined to hydrated state was reversible for both the parent and the hydrothermally treated samples. 27Al and 31P NMR MAS spectra showed a single resonance typical for AlPO4 type tetrahedra for the calcined parent and hydrothermally treated samples. Upon hydration, the single AlPO4 resonance signal split into three different signals as is the case for the corresponding 31P signals. By means of NH3-TPD measurement a loss of acidity was detected after the hydrothermal treatment as follows from a framework desilication. Nitrogen and water adsorption decreased systematically. At 210 °C a non-zeolitic, non-porous phase was irreversibly formed. The XRD pattern of this phase shows resemblance to a synthetic aluminium phosphate of the tridymite structure type. KW - Zeolite KW - Silicoaluminophosphate KW - SAPO-11 KW - Hydrothermal stability KW - Phase transformation PY - 2010 DO - https://doi.org/10.1016/j.micromeso.2009.08.003 SN - 1387-1811 SN - 1873-3093 VL - 132 IS - 1-2 SP - 31 EP - 36 PB - Elsevier CY - Amsterdam AN - OPUS4-21131 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartmann, A. A1 - Petrov, V. A1 - Buhl, J.-C. A1 - Rübner, Katrin A1 - Lindemann, Mathias T1 - Digestion reactions of paper sludge combustion ash in strong alkaline solutions at 60 °C N2 - Alkaline reactions of paper sludge combustion ash at low temperature (60 °C) were performed using a calcite-rich paper ash (PA 1) and a gehlenite-rich ash (PA 2). Strong alkaline conditions (8, 12, 16 M NaOH) were revealed at reaction times of 1–4 h and 12–24 h. Reactions were performed with pure ashes and in the presence of NaAlO2. The products were characterized by XRD, FTIR, SEM/EDX, gravimetry and chemical analysis. The conversion was found to proceed mainly in the period between 1 and 4 h. Portlandite and hydrogarnet were observed from PA 1 in 8 M NaOH. Onset of formation of Ca4Al2O6CO·311H2O beside Ca(OH)2 could be analyzed after reaction of PA 1 in 12 M and 16 M NaOH. Addition of NaAlO2 favored crystallization of hydrogarnet and Ca4-Al2O6CO·311H2O. For PA 2 gehlenite remained stable, but a high portlandite fraction was observed. Addition of NaAlO2 yielded hydrogarnet beside gehlenite in 8 M NaOH. Higher alkalinities favored crystallization of Ca4Al2O6-CO·311H2O and onset of dissolution of gehlenite. Finally transformation of Ca4Al2O6CO·311H2O into sodium aluminum silicate hydrate was observed. All results were discussed with regard to heavy metal distribution of the initial PA between the alkaline digestion solution and the products. In conclusion suitable applications of the products were proposed. KW - Paper sludge combustion ash KW - Alkaline digestion reaction KW - Portlandite KW - Katoite KW - Zeolite PY - 2016 DO - https://doi.org/10.1007/s10163-014-0320-4 SN - 1438-4957 SN - 1611-8227 VL - 18 IS - 1 SP - 132 EP - 145 PB - Springer CY - Tokyo AN - OPUS4-32827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartmann, A. A1 - Petrov, V. A1 - Buhl, J.-C. A1 - Rübner, Katrin A1 - Lindemann, Mathias T1 - Electrostatic filter ash from silane production as silicate substitute in zeolite chemistry N2 - This paper is a case study of complete substitution of sodium-metasilicate in zeolite Na-A synthesis by an electrostatic filterash (FA) arising in high amounts during silane waste incineration process.The silicate abundant FA is a suitable material for reinsertion in zeolite chemistry. This is shown in the presented investigation by the development of a model reaction process at low temperatures (50–60 °C) and short times (1.5–4 h). The experiments were performed under addition of NaAlO2 and variation of the alkalinity and the reaction period. Characterization and fine tuning of the process was mainly done by studying the kinetics of FA digestion and zeolite crystallization by XRD and chemical analyses (ICP-OES) of solutions and solids. It could be shown that pure FA was mostly dissolved (98%) in 8 m NaOH already after 1 h. Addition of NaAlO2 and crystallization for further 60 min under optimized conditions at 50 °C yielded to a suitable product. It consists of zeolite Na-A (92% by mass) beside some hydrosodalite (8% by mass). According to this low temperature short time process this study is a contribution for the development of energy efficient recycling solutions. KW - Electrostatic filter ash KW - Sodium-metasilicate KW - Zeolites KW - Silanes PY - 2016 DO - https://doi.org/10.1002/zaac.201500803 SN - 0044-2313 SN - 1521-3749 VL - 642 IS - 6 SP - 472 EP - 479 PB - WILEY-VCH Verlag GmbH & KGaA CY - Weinheim AN - OPUS4-38259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartmann, A. A1 - Petrov, V. A1 - Buhl, J.-C. A1 - Rübner, Katrin A1 - Lindemann, Mathias A1 - Prinz, Carsten A1 - Zimathies, Annett T1 - Zeolite synthesis under insertion of silica rich filtration residues from industrial wastewater reconditioning N2 - Zeolite synthesis was studied using two silica rich filtration residues (FR 1 and FR 2) as Si-source and sodium aluminate in a direct synthesis at 60°C at strong alkaline conditions (8 M - 16 M NaOH). In addition to these one-pot syntheses, a two-step process was investigated. Here, an alkaline digestion of FR at 60°C was followed by gel precipitation with sodium aluminate and gel crystallization under usual conditions of 80°C - 90°C. The results show that the substitution of chemical reagent sodium silicate by a waste material like FR as Si-source is possible but requires fine tuning of the reaction conditions as zeolite crystallization is a process under kinetic control. The solubility behaviour and impurities of the inserted filtration residues strongly influenced the course of reaction. Thus zeolites like hydrosodalite or intermediate zeolite between cancrinite and sodalite, or zeolite NaA or Z-21 in cocrystallization with hydrosodalite could be observed in the one pot syntheses already in a short time interval between 1 - 4 h depending on the alkalinity. The two step process yield to zeolites NaA and NaX in very good quality. The reaction process of FR in both reaction methods was characterized by chemical analyses, X-ray powder diffraction, Fourier transform infrared spectroscopy as well as scanning electron microscopy. Surface area and water content of selected products were further characterized by the BET-method and by thermogravimetry. Summing up the results, we can show that zeolite formation from filtration residues is possible by several reaction procedures as model cases for a re-use of industrial waste materials. Beside the importance for environmental protection, the reactions are of interest for zeolite chemistry as the re-use of FR is possible under economically conditions of low energy consumption at 60°C and short reaction periods. KW - Zeolites KW - Superalkaline Conditions KW - Filtration Residues KW - Re-Use of Industrial Waste KW - Reaction Kinetics KW - Silica Residue PY - 2014 DO - https://doi.org/10.4236/aces.2014.42015 SN - 2160-0392 SN - 2160-0406 VL - 4 SP - 120 EP - 134 PB - Scientific research publishing CY - Irvine, Calif., USA AN - OPUS4-31840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -