Research on the description and modification of the wetting phase during shape-selective agglomeration in suspensions.
Final Report Abstract
The project aimed to analyze and modify the wetting phase in shape-selective agglomeration in suspensions. This process, known as spherical agglomeration, is used to separate solid particles based on shape using differences in wettability in a three-phase liquid system. A critical factor is the contact angle between particles and both the suspension and binder liquids. Key aspects studied included the influence of particle shape, surface modifications (e.g., pH changes, surfactants), binder quantity, and energy input on agglomeration kinetics and separation efficiency. It was shown that shape-selective separation occurs predominantly during the initial wetting phase. The stirrer torque proved to be a viable in-line indicator of process dynamics. Advanced methods such as micro-CT imaging and FluidFM adhesion measurements were employed to understand how particle shape affects wettability and agglomerate morphology. It was found that plate-like and spherical graphite particles exhibit significantly different adhesion and wetting behaviors, resulting in distinct agglomerate structures. These were analyzed for size, sphericity, and internal organization. Separation trials using mixed graphite (platelets and spheres) under varying binder content and agglomeration times revealed that under certain conditions, the expected separation behavior may reverse. This was attributed to a change in the wetting mechanism in larger particle systems. The project significantly advanced the understanding of the wetting phase in shape-selective agglomeration and laid the groundwork for process control strategies.
Publications
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Morphological Study of Microagglomerates Obtained by Spherical Agglomeration Using X-ray Microtomography, World Congress on Particle Technology (WCPT), 2022
J. Schreier & U. Bröckel
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Mehrdimensionale selektive Umbenetzungsagglomeration – Bestimmung der Reinheit von Graphitagglomeraten. Chemie Ingenieur Technik, 95(10), 1623-1628.
Schreier, Julia & Bröckel, Ulrich
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The Morphology of Graphite Agglomerates During the Spherical Agglomeration Process, International Congress on Particle Technology (PARTEC), Nürnberg, 2023
J. Schreier & U. Bröckel
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Characterisation of spherical agglomeration process kinetics using torque mapping, Processes (2024)
J. Schreier & U. Bröckel
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Morphology of Graphite Agglomerates Obtained by Spherical Agglomeration via Propagation-Based X-Ray Microtomography. Image Analysis and Stereology, 43(1), 85-95.
Schreier, Julia & Bröckel, Ulrich
