<?xml version="1.0" encoding="UTF-8"?><rdf:RDF xmlns="http://purl.org/rss/1.0/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/">
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<title>Publication C: Insight into filter cake structures using micro tomography: The dewatering equilibrium</title>
<link>https://opara.zih.tu-dresden.de/xmlui/handle/123456789/1944</link>
<description>In recent years, non-destructive X-ray microscopy (XRM) has become a common method to characterize particle&#13;
systems in various scientific fields: Besides the size and shape of particles in bulk powders, the insight into filter&#13;
cake structures provides additional information about micro processes during filtration and dewatering.&#13;
Distributed particle properties mainly influence the porous network build-up with possible local deviation in&#13;
vertical and horizontal alignment. This article focusses on the model-based correlation between the distributed&#13;
particle properties and characteristic network parameters like tortuosity, pore radii and preferred capillaries for&#13;
dewatering, using tomography data as model input. Therefore, cake-forming filtration experiments were carried&#13;
out with a down-scaled, self-constructed in-situ pressure nutsch. The entire tomographic dataset consists of seven&#13;
individual scans at certain desaturation steps at different pressure levels.&#13;
For the experiments, a lognormal distributed particle system (crushed Al2O3) in the range of 55 to 200 μm&#13;
inside an aqueous suspension was used, containing additives for contrast enhancement. Image data processing&#13;
based on reconstructed 360° projections allows the identification of the background, solid particles and liquid&#13;
phase by a two-step segmentation.&#13;
The subsequent modelling uses experimentally verified particle size distributions from laser diffraction&#13;
measurements (integral value), 2D- (limited number of particles) as well as tomographic analysis, based on&#13;
calculated single-particle volumes given by the voxel-dataset (all particles within the scanned volume). To&#13;
characterize the porous network, a developed tetrahedron model is first applied to follow the shortest way&#13;
through the porous matrix, then again to calculate the widest capillary related to the pore entrance.&#13;
Furthermore, with information about the pore throat distribution and the wetting line from the tetrahedron side&#13;
faces, the force balance is evaluated. This results in an entrance pressure distribution, the capillary pressure&#13;
curve. Experimental data according to VDI 2762 built filter cakes and mercury intrusion tests are taken as&#13;
reference for validation.</description>
<items>
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<rdf:li rdf:resource="https://opara.zih.tu-dresden.de/xmlui/handle/123456789/1965"/>
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<dc:date>2026-04-07T11:52:30Z</dc:date>
</channel>
<item rdf:about="https://opara.zih.tu-dresden.de/xmlui/handle/123456789/1965">
<title>X-ray tomography scan of partially dewatered filter cake</title>
<link>https://opara.zih.tu-dresden.de/xmlui/handle/123456789/1965</link>
<description>X-ray tomography scan of partially dewatered filter cake
Löwer, Erik
X-ray tomography image of a partially dewatered filter cake. The initial slurry contains Al2O3 particles suspended in a potassium iodide-glycerol solution, which 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. The filter cake is dewatered by gradually increasing the pressure. A scan is taken in the equilibrium state after one pressure step. The data set contains seven pore filling grades S1-S7 (= seven pressure steps).
see note parameter.png in each measurement file for further measurement and reconstruction parameters
</description>
<dc:date>2021-01-01T00:00:00Z</dc:date>
</item>
</rdf:RDF>
