A more thorough understanding of the properties of bulk material structures in solid–liquid separation processes is essential to understand better and optimize industrially established processes, such as cake filtration, whose process outcome is mainly dependent on the properties of the bulk material structure. Here, changes of bulk properties like porosity and permeability can originate from local variations in particle size, especially for non-spherical particles. In this study, we mix self-similar fractions of crushed, irregularly shaped Al2O3 particles (20 to 90 μm and 55 to 300 μm) to bimodal distributions. These mixtures vary in volume fraction of fines (0, 20, 30, 40, 50, 60 and 100 vol.%). The self-similarity of both systems serves the improved parameter correlation in the case of multimodal distributed particle systems. We use nondestructive 3D X-ray microscopy to capture the filter cake microstructure directly after mechanical dewatering, whereby we give particular attention to packing structure and particle–particle relationships (porosity, coordination number, particle size and corresponding hydraulic isolated liquid areas). Our results reveal widely varying distributions of local porosity and particle contact points. An average coordination number (here 5.84 to 6.04) is no longer a sufficient measure to describe the significant bulk porosity variation (in our case, 40 and 49%). Therefore, the explanation of the correlation is provided on a discrete particle level. While individual particles < 90 μm had only two or three contacts, others > 100 μm took up to 25. Due to this higher local coordination number, the liquid load of corresponding particles (liquid volume/particle volume) after mechanical dewatering increases from 0.48 to 1.47. https://opara.zih.tu-dresden.de/xmlui/handle/123456789/1943 2026-04-07T11:54:11Z 2026-04-07T11:54:11Z Löwer, Erik https://opara.zih.tu-dresden.de/xmlui/handle/123456789/1963 2021-08-23T14:00:39Z 2021-01-01T00:00:00Z

X-ray tomography scans of filter cakes (feed slurry: variation in fraction of fines) Löwer, Erik X-ray tomography scans of partially dewatered filter cakes with variation of fine particles within the feed slurry. The mixture composition varies by addition of fines by 0, 20, 30, 40, 50, 60 and 100 vol.-%. The initial slurry contains Al2O3 particles suspended in a potassium iodide-glycerol solution and separated by cake-forming filtration. All filtration experiments took place in an in-situ apparatus inside the Zeiss Xradia 510 X-ray microscope. see note parameter.png in each measurement file for further measurement and reconstruction parameters

2021-01-01T00:00:00Z