TY - JOUR A1 - Singh, Amit Kumar A1 - Mishra, Biswajit A1 - Sinha, Om Prakash T1 - Reduction Kinetics of Fluxed Iron Ore Pellets Made of Coarse Iron Ore Particles N2 - The present work demonstrates a sustainable approach of using relatively coarser iron ore particles for ironmaking. The motivation is to reduce the energy consumption in the milling of the iron ore by utilizing coarser iron ore particles (+0.05 mm) and to select a suitable binder for improving pellet properties. Iron ore fines in the range of 0.05–0.25 mm was selected and classified into three size ranges. Fluxed iron ore pellets were prepared using lime as a binder for the basicity of 0, 1, and 2. Reduction of these pellets with a packed bed of coal fines was performed in the temperature range of 900–1200 °C for a duration of 30–120 min. The direct reduction kinetics of the iron ore pellets were studied by employing diffusion and chemical reaction control models to the experimental data. The results show that pellets made with coarser iron ore particles have improved reduction behavior and kinetics. The reduction reaction is found to be a mixed control. The activation energy for the reduction reaction varies from 44.3 to 74.76 kJ mol−1 as iron ore particle size decreases from 0.25 to 0.05 mm and basicity increases from 0 to 2. KW - Materials Chemistry KW - Metals and Alloys KW - Process Metallurgy KW - Iron making PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-598326 SN - 1611-3683 IS - 2300669 SP - 1 EP - 9 PB - Wiley VHC-Verlag AN - OPUS4-59832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piehl, Patrick T1 - Thermochemische Aufarbeitung von Stahlwerksstäuben und -schlämmen zur Zink- und Eisenrückgewinnung N2 - Stahlwerksstäube und -schlämme enthalten in der Regel Schwermetalle wie Zink, Blei und Cadmium, die ein direktes Recycling verhindern und diese Stoffe potenziell umweltgefährdend machen. Um diese Schwermetalle aus den Materialien zu entfernen, werden drei thermochemische Verfahren zur Aufarbeitung von Gichtgasschlamm, Elektroofenstaub und ähnlichen Stahlwerksstäuben vorgestellt. Zum einen kann die Mischung von Elektroofenstaub mit chloridhaltigen Lösungen, wie sie z. B. in der Titandioxidproduktion anfallen, gemischt werden, um bei der thermischen Behandlung Schwermetallchloride zu effektiv verdampfen. Weiterhin kann der im Gichtgasschlamm enthaltene Kohlenstoff genutzt werden, um in Mischungen aus Gichtgasschlamm und Elektroofenstaub bei der thermischen Behandlung als Reduktionsmittel zu wirken. Dieses Verfahren führt zur Rückgewinnung von Zink und metallischem Eisen und wird im Technikums- und Pilotmaßstab erprobt. Abschließend wird die Nutzung von Wasserstoff als Reduktionsmittel für Elektroofenstaub vorgestellt. Hierbei lässt sich der Reststoff potenziell klimaneutral in Eisenschwamm umwandeln, wobei die chemischen Grundlagen anhand von DTA-Experimenten und thermodynamischen Simulationen ergründet werden. T2 - Berliner Konferenz Metallkreisläufe CY - Berlin, Germany DA - 13.04.2024 KW - Elektroofenstaub KW - Gichtgasschlamm KW - Recycling KW - Ressourcenrückgewinnung KW - Zink PY - 2024 AN - OPUS4-59726 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Adam, Christian A1 - Jovičević-Klug, M. A1 - Raabe, D. T1 - Gewinnung von grünem Eisen und weiteren Wertstoffen aus Rotschlamm mittels Wasserstoffplasma N2 - Rotschlamm fällt in sehr großen Mengen bei der Herstellung von Aluminiumoxid an und wird fast ausschließlich deponiert. Es wird eine neue Technologie vorgestellt bei der das im Rotschlamm enthaltene Eisenoxid mittels Wasserstoffplasma reduziert wird. Es wird ein Reaktionsmechanismus über Titanomagnetit und Hercynit vorgeschlagen. T2 - Berliner Konferenz Metallkreisläufe CY - Berlin, Germany DA - 13.03.2024 KW - Rotschlamm KW - Wasserstoffplasma PY - 2024 AN - OPUS4-59722 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stawski, Tomasz A1 - Karafiludis, Stephanos A1 - Pimentel, Carlos A1 - Montes-Hernández, German A1 - Kochovski, Zdravko A1 - Bienert, Ralf A1 - Weimann, Karin A1 - Emmerling, Franziska A1 - Scoppola, Ernesto A1 - Van Driessche, Alexander E.S. T1 - Solution-driven processing of calcium sulfate: The mechanism of the reversible transformation of gypsum to bassanite in brines N2 - Here, we show that calcium sulfate dihydrate (gypsum) can be directly, rapidly and reversibly converted to calcium sulfate hemihydrate (bassanite) in high salinity solutions (brines). The optimum conditions for the efficient production of bassanite in a short time (<5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the better-known behaviour of the bassanite phase in low-salt environments. In low-salinity aqueous solutions, bassanite is considered to be metastable with respect to gypsum and anhydrite, and therefore gypsum-to-bassanite conversion does not occur in pure water. Interestingly, the high-salinity transformation of gypsum-to-bassanite has been reported by many authors and used in practice for several decades, although its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures was inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline phase for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios. KW - Industrial and Manufacturing Engineering KW - Strategy and Management KW - General Environmental Science KW - Renewable Energy, Sustainability and the Environment KW - Building and Construction KW - Calcium sulfate KW - Gypsum KW - Bassanite KW - Scattering KW - Raman KW - In situ KW - Synchrotron KW - BESSY KW - MySpot PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-594698 UR - https://www.sciencedirect.com/science/article/pii/S0959652624004591#appsec1 SN - 0959-6526 VL - 440 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-59469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schraut, Katharina A1 - Adamczyk, Burkart A1 - Adam, Christian A1 - Stephan, Dietmar A1 - Meng, Birgit A1 - Simon, Sebastian A1 - von Werder, Julia A1 - Hirsch, Tamino A1 - Manninger, Tanja T1 - Effect of gypsum on the hydration of fused cement clinker from basic oxygen furnace slag N2 - Fused cement clinker can be produced from molten basic oxygen furnace slag (BOFS) by way of a reductive thermochemical treatment. During the thermochemical treatment, oxidic iron is reduced to metallic iron and separated. The resulting low-iron slag has a chemical and mineralogical composition similar to ordinary Portland cement (OPC) clinker. In this study, the hydraulic reactivity of the fused clinker from BOFS with and without gypsum was investigated using isothermal calorimetry, differential scanning calorimetry, in situ X-ray diffraction and powder X-ray diffraction. Furthermore, a synthetic fused clinker without foreign ions and fused clinker produced by a mixture of both materials was studied. The hydraulic reaction of the fused clinker from BOFS was considerably slower than that of OPC. However, the reaction can be accelerated by adding gypsum as a sulfate carrier. Furthermore, the results showed an increased reaction rate with decreasing content of foreign ions such as Fe, P or Mn. KW - General Materials Science KW - Building and Construction PY - 2024 U6 - https://doi.org/10.1680/jadcr.23.00070 SN - 0951-7197 SP - 1 EP - 19 PB - Telford AN - OPUS4-59391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz A1 - Karafiludis, Stephanos A1 - Pimentel, C. A1 - Montes Hernandez, G A1 - Kochovski, Z A1 - Bienert, Ralf A1 - Weimann, Karin A1 - Emmerling, Franziska A1 - Scoppola, E A1 - Van Driessche, A T1 - Solution-driven processing of calcium sulfate: the mechanism of the reversible transformation of gypsum to bassanite in brines N2 - Calcium sulfate hemihydrate (CaSO4ᐧ0.5H2O), also known as bassanite, has been used as a precursor to produce gypsum (dihydrate, CaSO4ᐧ2H2O) for various construction and decorative purposes since prehistoric times. The main route to obtain hemihydrate is a thermal treatment of gypsum at temperatures typically between 150 °C and 200 °C to remove some of the structural water. In this contribution, we introduce (Fig. 1) a more efficient and sustainable method (T < 100 °C) that enables the direct, rapid, and reversibly conversion of gypsum to bassanite using reusable high salinity aqueous solutions (brines with c[NaCl] > 4 M). The optimum conditions for the efficientproduction of bassanite in a short time (< 5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the typical behaviour of the bassanite phase in low salt environments. Traditionally, hemihydrate is obtained through a solid state thermal treatment because bassanite is considered to be metastable with respect to gypsum and anhydrite in aqueous solutions, and therefore gypsum-to-bassanite conversion should not occur in water. Its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures is inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline structure for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios. T2 - Granada Münster Discussion Meeting GMDM 10 CY - Münster, Germany DA - 29.11.2023 KW - Gypsum KW - Bassanite KW - Calcium sulfate KW - Recycling KW - Scattering PY - 2024 AN - OPUS4-59162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hamann, Christopher A1 - Piehl, Patrick A1 - Weingart, Eric A1 - Stolle, Dirk A1 - Al-Sabbagh, Dominik A1 - Ostermann, Markus A1 - Auer, Gerhard A1 - Adam, Christian T1 - Selective removal of zinc and lead from electric arc furnace dust by chlorination–evaporation reactions N2 - Re-melting of scrap in an electric arc furnace (EAF) results in the accumulation of filter dust from off-gas treatment that predominantly consists of iron and zinc oxides. Filter dust is classified as hazardous waste due to its high contents of potentially toxic or ecotoxic elements such as Pb, Cr, Cd, and As. A promising processing route for this waste is selective chlorination, in which the non-ferrous metal oxides are chlorinated and selectively evaporated in form of their respective chlorides from the remaining solids via the process gas flow. Here, we investigate stepwise thermochemical treatment of EAF dust with either waste iron(II) chloride solution or hydrochloric acid at 650, 800, and 1100 ◦C. The Zn and Pb contents of the thermochemically processed EAF dust could be lowered from 29.9% and 1.63% to 0.09% and 0.004%, respectively. Stepwise heating allowed high separation between zinc chloride at the 650 ◦C step and sodium-, potassium-, and lead-containing chlorides at higher temperatures. Furthermore, the lab-scale results were transferred to the use of an experimental rotary kiln highlighting the possibilities of upscaling the presented process. Selective chlorination of EAF dust with liquid chlorine donors is, therefore, suggested as a potential recycling method for Zn-enriched steelworks dusts. KW - Electric arc furnace dust KW - Zinc KW - Selective Chlorination KW - Hazardous waste KW - Resource Recovery PY - 2024 U6 - https://doi.org/10.1016/j.jhazmat.2023.133421 SN - 0304-3894 VL - 465 SP - 1 EP - 13 PB - Elsevier AN - OPUS4-59345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jovičević-Klug, Matic A1 - Souza Filho, Isnaldi R. A1 - Springer, Hauke A1 - Adam, Christian A1 - Raabe, Dierk T1 - Green steel from red mud through climate-neutral hydrogen plasma reduction N2 - AbstractRed mud is the waste of bauxite refinement into alumina, the feedstock for aluminium production1. With about 180 million tonnes produced per year1, red mud has amassed to one of the largest environmentally hazardous waste products, with the staggering amount of 4 billion tonnes accumulated on a global scale1. Here we present how this red mud can be turned into valuable and sustainable feedstock for ironmaking using fossil-free hydrogen-plasma-based reduction, thus mitigating a part of the steel-related carbon dioxide emissions by making it available for the production of several hundred million tonnes of green steel. The process proceeds through rapid liquid-state reduction, chemical partitioning, as well as density-driven and viscosity-driven separation between metal and oxides. We show the underlying chemical reactions, pH-neutralization processes and phase transformations during this surprisingly simple and fast reduction method. The approach establishes a sustainable toxic-waste treatment from aluminium production through using red mud as feedstock to mitigate greenhouse gas emissions from steelmaking. KW - Multidisciplinary PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-594424 SN - 0028-0836 VL - 625 IS - 7996 SP - 703 EP - 709 PB - Springer Science and Business Media LLC AN - OPUS4-59442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maulas, Kryzzyl M. A1 - Paredes, Charla S. A1 - Tabelin, Carlito Baltazar A1 - Jose, Mark Anthony A1 - Opiso, Einstine M. A1 - Arima, Takahiko A1 - Park, Ilhwan A1 - Mufalo, Walubita A1 - Ito, Mayumi A1 - Igarashi, Toshifumi A1 - Phengsaart, Theerayut A1 - Villas, Edrhea A1 - Dagondon, Sheila L. A1 - Metillo, Ephrime B. A1 - Uy, Mylene M. A1 - Manua, Al James A. A1 - Villacorte-Tabelin, Mylah T1 - Isolation and Characterization of Indigenous Ureolytic Bacteria from Mindanao, Philippines: Prospects for Microbially Induced Carbonate Precipitation (MICP) N2 - Microbially induced carbonate precipitation (MICP), a widespread phenomenon in nature, is gaining attention as a low-carbon alternative to ordinary Portland cement (OPC) in geotechnical engineering and the construction industry for sustainable development. In the Philippines, however, very few works have been conducted to isolate and identify indigenous, urease-producing (ureolytic) bacteria suitable for MICP. In this study, we isolated seven, ureolytic and potentially useful bacteria for MICP from marine sediments in Iligan City. DNA barcoding using 16s rDNA identified six of them as Pseudomonas stutzeri, Pseudomonas pseudoalcaligenes, Bacillus paralicheniformis, Bacillus altitudinis, Bacillus aryabhattai, and Stutzerimonas stutzeri but the seventh was not identified since it was a bacterial consortium. Bio-cementation assay experiments showed negligible precipitation in the control (without bacteria) at pH 7, 8, and 9. However, precipitates were formed in all seven bacterial isolates, especially between pH 7 and 8 (0.7–4 g). Among the six identified bacterial species, more extensive precipitation (2.3–4 g) and higher final pH were observed in S. stutzeri, and B. aryabhattai, which indicate better urease production and decomposition, higher CO2 generation, and more favorable CaCO3 formation. Characterization of the precipitates by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR) confirmed the formation of three carbonate minerals: calcite, aragonite, and vaterite. Based on these results, all six identified indigenous, ureolytic bacterial species from Iligan City are suitable for MICP provided that the pH is controlled between 7 and 8. To the best of our knowledge, this is the first report of the urease-producing ability and potential for MICP of P. stutzeri, P. pseudoalcaligenes, S. stutzeri, and B. aryabhattai. KW - Calcium carbonate KW - Microbially induced carbonate precipitation (MICP) KW - Ureolytic bacteria PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-600888 VL - 14 IS - 4 SP - 1 EP - 15 PB - MDPI AN - OPUS4-60088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Machado Ferreira de Araujo, F. A1 - Duarte-Ruiz, D. A1 - Saßnick, H.-D. A1 - Gentzmann, Marie C. A1 - Huthwelker, T. A1 - Cocchi, C. T1 - Electronic Structure and Core Spectroscopy of Scandium Fluoride Polymorphs N2 - Microscopic knowledge of the structural, energetic, and electronic properties of scandium fluoride is still incomplete despite the relevance of this material as an intermediate for the manufacturing of Al−Sc alloys. In a work based on first-principles calculations and X-ray spectroscopy, we assess the stability and electronic structure of six computationally predicted ScF3 polymorphs, two of which correspond to experimentally resolved single-crystal phases. In the theoretical analysis based on density functional theory (DFT), we identify similarities among the polymorphs based on their formation energies, chargedensity distribution, and electronic properties (band gaps and density of states). We find striking analogies between the results obtained for the ow- and high-temperature phases of the material, indirectly confirming that the transition occurring between them mainly consists of a rigid rotation of the lattice. With this knowledge, we examine the X-ray absorption spectra from the Sc and F K-edge contrasting firstprinciples results obtained from the solution of the Bethe−Salpeter equation on top of all-electron DFT with high-energy-resolution fluorescence detection measurements. Analysis of the computational results sheds light on the electronic origin of the absorption maxima and provides information on the prominent excitonic effects that characterize all spectra. A comparison with measurements confirms that the sample is mainly composed of the high- and low-temperature polymorphs of ScF3. However, some fine details in the experimental results suggest that the probed powder sample may contain defects and/or residual traces of metastable polymorphs. KW - Scandium KW - X-ray spectroscopy PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-570727 SN - 0020-1669 VL - 62 IS - 10 SP - 4238 EP - 4247 PB - ACS Publications CY - Washington DC AN - OPUS4-57072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -