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

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 are produced. Instead of conventional fluidization, special spouted bed equipment with adjustable air inlet is used for processing. High-velocity air inlet jets help to shift the dynamic equilibrium between aggregation and breakage towards smaller and stronger agglomerates in this kind of equipment. Regarding the characterization of agglomerates, new methods to reconstruct 3D agglomerate structure from 2D imaging data are developed. In this frame, the level of sub-agglomerate mixing can be identified and pushed towards individual nanoparticles by use of non-flame, i.e. not sintered, raw material. To describe the process, novel population balances and discrete models are used. Hetero-agglomerate conductivity (thermal, electrical) is measured and modelled.