Technische Universität Bergakademie Freiberg

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Browsing Technische Universität Bergakademie Freiberg by Subject "4"

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  • ItemOpen Access
    3 tomographic data sets of nano-CT measurements of a 30:70 vol-% mixture of talcum and saxolite
    (Technische Universität Bergakademie Freiberg, 2022-09-02) Ditscherlein, Ralf
    All 3 data sets are sub-volumes (Field of View approx. 65 µm) of a total sample of a particle mixture of talc and saxolite fixed in a matrix by means of epoxy resin and spacer particles (nanometre-sized carbon black particles, 150 nm equivalent spherical diameter). The primary analysis was carried out using nano-CT. The reconstructed result data are stored in the form of TIF files as sectional images (folder "rotated"). In addition, a correlation was carried out by means of EDXS analytics, the chemical information of which was used to train a segmentation algorithm. Since EDXS analysis requires a planar surface, the sample was further processed using FIB. The divergence of the ion beam produces a slight angular deviation from the perpendicular of the nano-CT volume, which necessitated a rotation of the initial volume data (--> "rotated"). The correlated result data of the particle-discrete phase information are also stored ("rotated segmented").
  • ItemOpen Access
    Colloidal probe atomic force microscopy measurements on pristine gas bubbles, agglomerates and particle-laden gas bubbles
    (Technische Universität Bergakademie Freiberg, 2024-07-08) Nicklas, Jan
    This dataset contains experimental Atomic Force Microscopy (AFM) force-displacement measurements of poorly wetted alumina particles (colloidal probes) < 15 µm interacting with pristine gas bubbles, agglomerates and particle-laden gas bubbles (hetero-coagulates) in an aqueous environment. The data was generated in the context of the Collaborative Research Center CRC 920 (Project ID 169148856 – subproject B04) that is funded by the German Research Foundation (DFG). The data set is of interest for researches that study the agglomeration or hetero-coagulation in liquid environment, and it is expected to be of particular interest to those that are concerned with the simulation and modeling of these processes (for example by Discrete Element Method). The AFM raw data was baseline corrected to increase the accessibility of the data sets to those less familiar with the AFM. A detailed interpretation of the AFM data in this repository is found in https://doi.org/10.1021/acs.langmuir.3c01781 and https://doi.org/10.1016/j.colsurfa.2024.134660.
  • ItemOpen Access
    Corrosion and Process Analysis of a Preoxidized MgO Recyclate-based Cermet Anode in Laboratory-Scale Na-Cryolite Molten Salt Electrolysis of Aluminum at 1000 °C
    (Technische Universität Bergakademie Freiberg, 2026-07-14) Adamczyk, Alexander; Hossain, Farhan; Garcia Paz, Felipe A.; Yaroshevskyi, Serhii; Vogt, Daniel; Aneziris, Christos G.; Charitos, Alexandros
    The development of inert anodes for aluminum electrolysis remains challenging due to the high corrosivity of cryolite-based melts at 950°C–1000°C. This study investigates the corrosion and process behavior of a carbon-free MgO–steel cermet anode derived from refractory recycling during laboratory-scale Na-cryolite electrolysis at 1000°C, focusing on the effect of a pre-oxidation treatment on its corrosion behavior. In the as-sintered state, MgO grains are mechanically bonded to a 316L steel matrix with interfacial porosity that limits corrosion resistance. Pre-oxidation at 900°C for 24 h forms a dense Mg–M–O (M=Fe, Cr) oxide-rich surface layer, sealing pores and improving resistance to cryolite infiltration, albeit at the cost of reduced electrical conductivity, which translated into an overall higher cell voltage compared to the as-sintered state. During electrolysis, this layer degrades under anodic polarization, O2 evolution, and fluorination. The surface transforms into a Fe–O-rich magnetite layer (Fe3O4), while a Cr-containing oxide and an in situ Mg–Fe–O transition zone form beneath, maintaining partial protection. Overall, pre-oxidation effectively delays electrolyte penetration by converting MgO into new oxide phases but introduces conductivity losses and surface instability. The results highlight both the potential and limitations of MgO-based cermet anodes for sustainable aluminum production.
  • ItemOpen Access
    Data for ultrasonic decoating of solid oxide cells (H2Giga-ReNaRe)
    (Technische Universität Bergakademie Freiberg, 2023-10-27) Kaiser, Carlo
    This file contains the raw data and data obtained from it for the publication "Ultrasonic decoating as a new recycling path to separate oxygen side layers in solid oxide cells". The file consists of: 1. an Excel document in which all quantitative data are compiled 2. a folder with all available raw images before and after ultrasonic decoating as well as binary images after segmentation for each investigated cell type
  • ItemPublic Metadata
    DFG 465144480: Boron-free self-glazing Al₂O₃-C refractories
    (Technische Universität Bergakademie Freiberg, 2026-04-01) Roungos, Vasileios; Gehre, Patrick; Salpagarov, Eldar; Aneziris, Christos G.
    Al₂O₃-C refractories are extensively used as functional components in the continuous casting of steel. These high-duty products such as submerged entry nozzles, ladle shrouds, and monoblock stoppers contain up to 30 wt.-% carbon and present excellent mechanical, thermal and chemical properties, enabling the cost- and quality-effective implementation of the continuous casting process. Ceramic glazes are externally applied on Al₂O₃-C flow control refractory products to protect carbon from oxidation. These glazes typically contain boron. However, the increasing requirements for clean steel technology along with environmental- and health issues associated with boron compounds will make the utilization of boron-free glazes a necessity in the upcoming years. New boron-free self-glazing Al₂O₃-C formulations with sodium carbonate, wollastonite and magnesia additives were developed with the assistance of the FactSage software tool. These compositions presented a softening point in the range of 1000-1100 °C for self-glaze formation, which is the typical preheating temperature range for Al₂O₃-C functional refractory products. In addition, the influence of particle packing on their oxidation resistance was investigated, based on established particle size distribution models.
  • ItemPublic Metadata
    DFG 465144480: Impact of cyclic CIP on the oxidation resistance and physical properties of a newly developed boron-free self-glazing Al2O3-C refractory
    (Technische Universität Bergakademie Freiberg, 2026-03-31) Roungos, Vasileios; Gehre, Patrick; Brachhold, Nora; Fischer, Undine; Aneziris, Christos G.
    The impact of cyclic cold isostatic pressing (C-CIP) on the oxidation resistance and physical properties of a boron-free self-glazing Al2O3-C refractory for steel casting applications was investigated. Pulsations with amplitudes of 20, 40 and 65 MPa were thereby applied either at maximum isostatic pressure or at increasing pressure. The maximum isostatic pressures applied were 80, 100 and 150 MPa, respectively. Both cycling pressurizations improved the oxidation resistance and physical properties. Higher densities were obtained at higher cycling amplitudes, in particular when the pulsations were applied at maximum isostatic pressure. In addition, the evolution of a broader pore size distribution with peaks at pores larger than 4 μm was found. The pore size distributions of the samples pressed by C-CIP at increasing pressure were narrower, with higher peaks at smaller pore sizes in the area of 2.5 μm. It was shown that utilizing cycling pressurization enables tailoring of pore sizes in carbon-bonded refractories as well, providing a powerful tool for the material design of refractories.
  • ItemOpen Access
    Epoxy-Based Particle Sample Preparation with Nano-Graphite as Spacer - RAW Data (Particle Sample Preparation) - Different mixtures (by volume) of graphite-nanoparticles and analysis particles
    (Technische Universität Bergakademie Freiberg, 2020-05-08) Ditscherlein, Ralf
    To get good image segmentation results in tomographic analysis methods, particles has to be seperated from each other while embedding them into a matrix. Low X-ray absorbing nano-graphite below the voxel resolution of the system is mixed with the analysis particles to form a shell to avoid direct particle-particle contact. After mixing it with epoxy resin, the paste is sucked into a polymeric tube of 2 mm inner diameter. After hardening, the formed cylinder was scanned with an X-ray microscope (ZEISS Xradia Versa 510) with the following parameters: 80 keV, 7 W, 360°, 2001 projections, 1 s exposure time, 2 µm voxel size, binning 2. After scannning, the following filters were applied while reconstruction with ZEISS reconstructor: Beam Hardening Correction 0.05, Smoothing 0,7. Detailed overview of the parameters is summarized as screenshots within the repository. To determine an optimal mixture of the two components, the following volume-fractions were analysed: Nanoparticle:Particle 20vol-%:80vol-% 40vol-%:60vol-% 60vol-%:40vol-%
  • ItemOpen Access
    Evaluating the influence of discharge depths of lithium-ion batteries on the mechanical recycling process
    (Technische Universität Bergakademie Freiberg, 2024-04-16) Wilke, Christian; Peuker, Urs; Kaas, Alexandra
    This dataset contains the information for the figures of the publication "Evaluating the influence of discharge depths of lithium-ion batteries on the mechanical recycling process".
  • ItemOpen Access
    Experimental Cake Filtration Data and Code for Analysis, Graph Generation
    (Technische Universität Bergakademie Freiberg, 2021-12-08) Buchwald, Thomas
    This collection belongs to the doctoral thesis "Nonlinear Parameter Estimation of Experimental Cake Filtration Data". Most of the content are Jupyter notebooks which contain the Python code which reproduces graphs found in the thesis from the original experimental data. The lab practice dataset that contains 500 filtration experiments is contained in the folder for section 3.5. The notebooks are not strictly sorted by section. At any rate, the Readme will guide you to the notebook which produces a certain graph, if it is not part of the main notebook of that specific section. The original Python environment was set up with Anaconda. Please use the provided .yml file to create a Python environment which contains all the necessary packages. Some notebooks may not work with the most current versions of the packages, so updating is not necessarily a good idea.
  • ItemOpen Access
    Fully saturated and dewatered filter cakes at different resolutions
    (Technische Universität Bergakademie Freiberg, 2021-08-23) Löwer, Erik
    Appendix to Publications A to E with investigations of different particle systems (material, size and shape variation). X-ray tomography image of fully and partially dewatered filter cakes. The initial slurries contains mica, dolomite, quartz, limestone or glass particles suspended in a potassium iodide-glycerol brine. The different shaped particles were separated by cake-forming filtration followed by dewatering. All filtration and dewatering experiments took place in an in situ apparatus within the Zeiss Xradia 510 X-ray microscope. The filter cake is dewatered until the minimum degree of saturation is reached within the pore space. A scan is taken at the equilibrium state before and after dewatering. A small section in the center of the desaturated filter cakes was additionally measured at a significantly smaller field of view and higher resolution in order to be able to determine the local contact angle in addition to the saturation distribution and the size of the individual liquid bridges.
  • ItemPublic Metadata
    GRK 2802: Influence of Sample Preparation and Processing Procedures on the Thermal Diffusivity of MgO-C Refractories
    (Technische Universität Bergakademie Freiberg, 2026-02-12) Pan, Luyao; Wulf, Rhena; Stadtmüller, Till M. J.; Aneziris, Christos G.; Fieback, Tobias M.
    Reliable measurement of thermal diffusivity of MgO-C refractories is impeded by diverse sample preparation and processing procedures. In this study, the impacts of coking sequence, machining conditions, microstructural inhomogeneity, and graphite coating on the results obtained using the laser flash apparatus at room temperature are systematically evaluated. Specifically, machining samples after coking prevents surface oxidation compared with machining before coking. Mechanical damage is reduced by water-assisted machining, resulting in increased thermal diffusivity. However, when applied before coking, water-assisted machining leads to brucite formation, and thermal diffusivity is consequently decreased. Furthermore, uniaxial pressing induces microstructural inhomogeneity, with finer grains on the surface, thereby lowering thermal diffusivity. Uncoated samples overestimate thermal diffusivity compared with graphite-coated ones due to MgO translucency. To clarify these mechanisms, complementary analyses including phase, microstructural, and compositional characterization were performed to support these findings. The results demonstrate that the optimal preparation of MgO-C samples for measurements using the laser flash apparatus involves coking first, followed by water-assisted machining, and subsequent graphite coating. Such a preparation procedure enhances measurement reliability, providing practical guidance for standardized thermophysical property evaluation of MgO-C refractories.
  • ItemPublic Metadata
    GRK 2802: Spinel coatings produced via oxidation of an AISI 316L-MgO composite
    (Technische Universität Bergakademie Freiberg, 2026-02-03) Mehdizadehlima, Mahnaz; Schimpf, Christian; Martin, Stefan; Fabrichnaya , Olga; Rafaja, David
    The possibilities of producing protective spinel coatings on the surface of an AISI 316L-MgO composite via hightemperature oxidation at 800 ◦C, 900 ◦C and 1000 ◦C were explored using a combination of structure and microstructure analyses, and thermodynamic calculations. The structure and microstructure of the coatings were analyzed in situ and ex situ using high-temperature and conventional X-ray diffraction, scanning electron microscopy, electron backscatter diffraction and X-ray spectroscopy. The ex situ analyses identified the oxidation and reaction products and revealed their spatial distribution within the surface coating. The in situ analyses helped to describe the oxidation and reaction kinetics. It was found that Cr2O3, which forms on the surface of oxidized austenite grains, reacts quickly to the MgCr2O4 spinel, when it comes in contact with MgO. Longer oxidation times and higher oxidation temperatures facilitate the formation of Fe2O3 and MgFe2O4, which partially intermix with Cr2O3 and MgCr2O4. As the spinel phases are formed via interdiffusion and as their molar volume is larger than the molar volume of the original phases (MgO, Cr2O3/Fe2O3), they overgrow the surface of the MgO grains. This mechanism provides a basis for controlled growth of protective spinel coatings on the surface of the AISI 316L-MgO composites.
  • ItemPublic Metadata
    GRK2802: Microstructure Design of Steel-Spinel Composites via Spark Plasma Sintering Process
    (Technische Universität Bergakademie Freiberg, 2026-07-03) Mehdizadehlima, Mahnaz; Schimpf, Christian; Martin, Stefan; Fabrichnaya, Olga; Rafaja, David
    Compact steel-spinel composites with a specific microstructure were produced by spark plasma sintering, using powder mixtures of high-alloy steel AISI 316L, MgO, and Cr2O3 or Fe2O3 as starting materials. The reaction diffusion between MgO and Cr2O3 or Fe2O3 always led to the formation of an Mg-based spinel. The thermodynamic phase stability of the respective corundum-like oxide with respect to the oxygen partial pressure decided about the presence or absence of side reactions, which were utilized as an efficient tool for microstructure design of the steel-spinel composites.The use of Fe2O3 as one of the starting compounds initiated various redox reactions that promoted the formation of mixed spinel phases at the steel/ceramic interface and the transformation of MgO to (Mg, Fe)O, which accommodates, in addition to iron, also other divalent alloying elements from the steel. The phase composition of the composites and the spatial distributions of individual phases and their chemical compositions were investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron backscatter diffraction, and electron probe microanalysis. The microstructure formation was substantiated by thermodynamic calculations. The role of oxidizing and reducing agents that are involved in the microstructure design is discussed.
  • ItemOpen Access
    High-resolved X-ray tomography scan of dewatered filter cakes and sessile droplets
    (Technische Universität Bergakademie Freiberg, 2021-08-23) Löwer, Erik
    X-ray tomography image of dewatered filter cakes at irreducible saturation. The initial slurry contains Al2O3 particles suspended in a potassium iodide-glycerol solution. These were separated by cake-forming filtration with subsequent dewatering. All filtration and dewatering experiments took place in an in situ apparatus within the Zeiss Xradia 510 X-ray microscope. High resolution scans are acquired in the equilibrium state after dewatering at different locations within the cake structure to measure the local three-phase contact angle. The data are validated by sessile droplet experiments on substrates of the same material within the X-ray microscope.
  • ItemOpen Access
    Influence of a pyrolysis at different temperatures on the mechanical recycling efficiency of Li-ion batteries
    (Technische Universität Bergakademie Freiberg, 2024-12-12) Kaas, Alexandra; Wilke, Christian; Born, Jannik; Ahuis, Marco; Kwade, Arno; Peuker, Urs
    The integration of a pyrolysis stage into the mechanical recycling process of Li-ion batteries is supposed to improve the decoating of the electrodes, the recovery of valuable components and the overall quality of the products. The effectiveness of the pyrolysis process depends on the applied temperature as the various components of a Li-ion battery melt, evaporate and decompose at different temperatures. The decomposition temperature of the cathode binder is a crucial factor in the thermal mechanical recycling process. Temperatures below this threshold have a negative impact on the recovery rates, as the melting of binder and plastics reduces the efficiency of the recovery process. Conversely, higher temperatures facilitate the recovery of the cathode coating metals (Ni, Co, Li) into the black mass. The majority of the metals (92-98%) are recovered and, following hydrometallurgical treatment, can be reused for cell production, thereby closing the loop and reducing the consumption of raw materials and enhancing the sustainability of batteries. Moreover, the decomposition of the organic components, including binders and plastics, improves the quality of the products, thereby reducing the necessity and extent of further treatment.
  • ItemOpen Access
    Influence of shredder and mill settings on the material recoveries and product qualities of a two-stage mechanical recycling process of automotive lithium-ion batteries
    (Technische Universität Bergakademie Freiberg, 2025-03-12) Kaas, Alexandra; Wilke, Christian; Peuker, Urs
    For a two stage shredding and milling process the yield of black mass and the elemental recovery of critical elements Ni and Li s investigated. I can be shown that the quality of the products resulting from the mechanical recycling of lithium-ion batteries significantly depends upon the parameters employed during the shredding process. Modifications to the settings have the potential to exert a considerable impact on the particle size, liberation of composites and de-coating of electrodes. The discharge grid size employed during the first shredding step shows a significant influence on the downstream separation behaviour of the casing material and separator foil. The mill speed utilised during the second comminution step determines the separation achieved between the cathode and anode. A reduction in grid size employed during the first shredding stage results in an increase in black mass yield, although the recovery of the casing is diminished. In total Ni recovery for all setting combinations is similar, a lower recovery in the first shredding step is compensated by a higher recovery after the second comminution. It was observed that an overall increase in the mill speed above 1750 rpm resulted in elevated levels of copper contamination within the black mass. The influence of eleven distinct combinations of shredder and mill settings on the black mass yield and its composition, the recovery of the separator foil and the casing, as well as the separation behaviour of the anode and cathode, were investigated.
  • ItemOpen Access
    Jupyter Notebook for the Publication "A Framework for the Description of Multidimensional Particle Separation Processes"
    (Technische Universität Bergakademie Freiberg, 2023-10-27) Buchwald, Thomas
    Jupyter Notebook that reproduces all used graphs from the raw data. The produced graphs are not the final figures in the publication - several editing steps were undertaken to include color bars, etc.
  • ItemOpen Access
    Jupyter Notebook zur Erstellung der Abbildungen des Aufsatzes "Beschreibung von Trennoperationen mit mehrdimensionalen Partikeleigenschaftsverteilungen"
    (Technische Universität Bergakademie Freiberg, 2022-07-01) Buchwald, Thomas
    Jupyter Notebook, welches die Rohdaten bei Bedarf einliest und die Diagramme aus den Rohdaten erstellt. Falls keine Python-Installation zur Verfügung steht, wird ein HTML des Notebooks bereitgestellt. Dabei werden nicht die finalen Diagramme erstellt; diese ergeben sich erst durch Zusammensetzen in einem Vektorgrafikprogramm.
  • ItemOpen Access
    Multi-Scale Tomographic Analysis for Micron-Sized Particulate Samples - RAW Data
    (Technische Universität Bergakademie Freiberg, 2020-01-08) Ditscherlein, Ralf; Martins de Souza e Silva, Juliana
    This repository includes the reconstructed TIFF-files from multiple scale tomographic analysis of particles in an embedding matrix (overall volume and 3 sub-volumes in 2 different magnification steps): LARGE (low-resolution) (due to filesize partioned in part I, II, III, IV and V) 1 large volume of particle mixture (50/50) of spheres (0.2 - 2 µm) and fibres (diameter: 10 µm length: 100 - 1000 µm) embedded in a matrix (wax, 15 vol-%). The large volume was extracted with an automated syringe into a small polymeric tube (diameter: 1.8 mm) and shock frozen. After that the sample was mounted on top of a needle pin and scanned with a micro-CT (ZEISS Versa510) at 80 keV, 7 W, low energy filter LE4, exposure time 2 s, optical magn. 4x, 3201 projections, 360°, Binning 2, Voxelsize 1.5 µm SubSample - MEDIUM (medium-resolution) (SubSample 1, 2, 3) After the scan, the LARGE volume was cutted in small disks and cutted a second time in little bars. Again, mounted on top of a needle pin and scanned with same parameters, BUT with 40x optical magnification and 25 s exposure time to go down to a system limit of 0.3 µm Voxelsize (again with ZEISS VERSA510). This was done 3 times in different heights of the LARGE volume SubSample - HIGH (high-resolution) (SubSample 1, 2, 3) After that, all SubSamples were scanned again with a nano-CT (ZEISS ULTRA810) at 5.4 keV, 60 s exposure time, 901 projections, 180°, Binning 1 to reach Voxelsize of 0.064 µm
  • ItemOpen Access
    Reconstructed CT data of filter cakes
    (Technische Universität Bergakademie Freiberg, 2024-04-12) Löwer, Erik
    CT data of two filter cakes, built from glass beads (B70) and quartz sand (BCS201) in an in-situ pressure nutsch according german guideline VDI 2762-2. The soda-lime glass beads (density 2.55 g/cm³, 72.30 m.-% SiO2, 13.30 m.- % Na2O, 8.90 m.-% CaO and 4.00 m.-% MgO) of the size of 70 < x < 110 μm were purchased from Sigmund Lindner GmbH, Germany, and are manufactured via dry spraying. The quartz sand (density 2.65 g/cm³, 99.1 m.-% SiO2 with traces of Fe2O3, Al2O3 and TiO2 with < 0.3 m.-%) was purchased from Strobel quartzsand GmbH, Germany, in the fraction x < 200 μm, coming from a comminution process. For the filtration experiments, the solids are suspended in an aqueous solution of de-ionized water, potassium iodide (25 mM) and glycerol (24 m-%), resulting in a density of 1.10 g/cm². After filtration until gas breakthrough, the filter cakes are measured tomographically (ZEISS Xradia 510 Versa). Research data to publication 'Stochastic 3D modeling of artificial filter cake structures based on µ-CT image'. Image data from µ-CT measurements of filter cakes, which serve as a model basis and validation of the artificial filter cakes for the publication. Abstract: In order to link the properties of a feed stream to those of a product stream in separation operations such as cake filtration, a more comprehensive database is required. For this purpose, a stochastic 3D model for generation of virtual filter cake structures is constructed and calibrated to tomographic image data of experimentally built filter cake structures. Within this model, artificial particles are simulated using mixed Gaussian random fields on a sphere, which are then spatially arranged to form a three-dimensional artificial filter cake that is validated with respect to geometric descriptors that were not used for model fitting, such as constrictivity, porosity, tortuosity and specific surface area. By adjusting interpretable parameters of the model, a large data base of systematically varying artificial filter cakes can be generated, allowing for transfer functions to be determined and structure-property relationships to be statistically investigated.