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Faculty 04: Production Engineering - Mechanical Engineering and Process Engineering: Priority Programme 2289 Hetero-Aggregates

Hetero-aggregation of fluidized nanoparticles and solid-containing aerosol droplets

Microscopic image of exemplary heteroaggregate of nanoparticles.
© Kolan, S.R., Wang, R., Hoffmann, T., Tsotsas, E.
Exemplary heteroaggregate of nanoparticles. Left: SEM image (bar length = 2 µm); centre: EDXS image with Al in green; right: EDXS image with Ti in purple. The evaluation for this heteroaggregate resulted in HoMm = 0.86 with ROI = 200 nm (Kolan, S.R., Wang, R., Hoffmann, T., Tsotsas, E.: Mixing nanoparticles in a Procell type spouted bed, Powder Technol., 431 (2024), 119129).

Project Leader :

Prof. Dr.-Ing. habil. Evangelos Tsotsas
Otto von Guericke  University Magdeburg

The project aims at mixing in fluidized bed very small particles (nanoparticles or submicron particles) of different composition to hetero-agglomerates, which may additionally be encapsulated or coated with the help of aerosol droplets that contain embedding solid material. In this way, binary or ternary particulate composites of extremely finely dispersed constituents will be produced, aiming at new and superior properties. Instead of conventional fluidization, special spouted bed equipment with adjustable air inlet will be used for processing. High-velocity air inlet jets, which may be assisted by an immersed impactor and admixed large breaker particles, help to shift the highly dynamic equilibrium between aggregation and breakage towards smaller and stronger agglomerates in this kind of equipment. Submicron aerosol will be generated by a novel technique which is simple, robust and easily scalable. Regarding the characterization of agglomerates, new methods to reconstruct 3D agglomerate structure from 2D imaging data will be developed. In this frame, the level of sub-agglomerate mixing will be identified and pushed towards individual nanoparticles by use of non-flame, i.e. not sintered, raw material.

Finally, the project will set ground for hierarchical discrete models that can describe process kinetics and agglomerate formation even with very large number of primary particles. In SPP 2289, methodic cooperation and technical complementarity is seen with, especially, projects on crossing flames, high shear mixing, assisted fluidization, and imaging.  

 

Updated by: Claudia Sobich
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