TY - JOUR A1 - Vogler, Nico A1 - Drabetzki, Philipp A1 - Lindemann, Mathias A1 - Kühne, Hans-Carsten T1 - Description of the concrete carbonation process with adjusted depth resolved thermogravimetric analysis N2 - The thermal gravimetric analysis (TG) is a common method for the examination of the carbonation progress of cement-based materials. Unfortunately, the thermal properties of some components complicate the evaluation of TG results. Various hydrate phases, like ettringite (AFt), C-S-H and AFm decompose almost simultaneously in the temperature range up to 200 °C. Additionally, physical bound water is released in the same temperature range. In the temperature range between 450 °C and 600 °C the decomposition of calcium hydroxide and amorphous or weakly bound carbonates takes place simultaneously. Carbonates, like calcite, from limestone powder or other additives may be already contained in the noncarbonated sample material. For this research an attempt was made to minimise the influence of these effects. Therefore, differential curves from DTG-results of non-carbonated areas and areas with various states of carbonation of the same sample material were calculated and evaluated. Concretes based on three different types of cement were produced and stored under accelerated carbonation conditions (1 % CO2 in air). The required sample material was obtained by cutting slices from various depth of previously CO2-treated specimen and subsequent grinding. During the sample preparation, a special attention was paid that no additional carbonation processes took place. As reference method for the determination of the carbonation depth the sprayed application of phenolphthalein solution was carried out. Microscopic analysis where examined to confirm the assumptions made previously. Furthermore, the observed effect of encapsulation of calcium hydroxide by carbonates caused by the accelerated carbonation conditions was examined more closely. KW - Microscopy KW - Accelerated carbonation KW - Carbonation behaviour KW - Concrete KW - Thermal Analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530571 DO - https://doi.org/10.1007/s10973-021-10966-1 VL - 147 IS - 11 SP - 1 EP - 14 PB - Springer AN - OPUS4-53057 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 - 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 - CONF A1 - Sturm, Patrick A1 - Gluth, Gregor A1 - Lindemann, Mathias A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Brouwers, H.J.H. ED - Bernal, S.A. ED - Provis, J.L. T1 - Structural investigations on one-part geopolymers after different drying regimes T2 - 34th Cement and concrete science conference CY - Sheffield, UK DA - 2015-09-14 KW - Geopolymers KW - One-part mix PY - 2015 SP - 37 EP - 40 AN - OPUS4-34554 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 - Vogler, Nico A1 - Lindemann, Mathias A1 - Drabetzki, Philipp A1 - Kühne, Hans-Carsten T1 - Alternative pH-indicators for determination of carbonation depth on cement-based concretes N2 - The most common method for determination of the carbonation depth is the sprayed application of indicator solutions, Phenolphthalein in particular. Since the aerosols of Phenolphthalein are suspected to be carcinogenic, efforts have been intensified to use alternative indicators for the determination of carbonation depth. The subject and aim of this research paper are to examine indicator solutions from Alizarin Yellow R, Thymol Blue and a Mixed Indicator. These indicator solutions are commercially available and are not suspected to be carcinogenic. For the purpose of this research, samples previously stored under accelerated carbonation conditions (1% CO2) were examined by thermogravimetric analysis (TGA) and examination of the pH value. Additionally, the electrolytic back-titration for determination of total CO2 amount was carried out comparatively to TGA. KW - Thermal analysis KW - Accelerated carbonation KW - pH-indicators KW - Concrete PY - 2020 DO - https://doi.org/10.1016/j.cemconcomp.2020.103565 VL - 109 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-50458 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -