SPP 2289:  Creation of synergies in tailor-made mixtures of heterogeneous powders: Hetero aggregations of particulate systems and their properties

• Subject Area: Thermal Engineering/Process Engineering
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 441399220

Mixing of disperse systems (particles and powders) is a traditional unit operation of process engineering which is of central importance in various technological areas. Applications of mixed particulate systems range from processing of food, pharmaceutical and chemical substances to material processing and materials engineering. Functional mixing of different particle types (hetero-aggregation) has the potential of creating outstanding new properties of dispersed products, which depend on the mixture composition and on various secondary process conditions (e.g. agglomeration, coating). In this context, a new product property can emerge from the direct contact of different particles (hetero-contact) and thus by the resulting interface between the respective particular components. Many applications have shown that these hetero-contacts are of fundamental importance for specific functional properties. In most cases the new properties result from the transfer of charges, mass, heat, forces, or moments without the need of a chemical reaction of its components. Thus, the quality of such a particulate mixture is directly linked to the contact points and interfaces of different particles and the details of the interaction between its species in contact. The new property from the contact zone controls the material and product properties of the entire system that is named hetero-contact in the context of SPP 2289. Direct information about hetero-contact quality (e.g. number of contacts, transport properties between different particle types) could therefore be the base for a fundamental description of the new properties of the particle mixture (quality of the mixture and material function). At the same time, the hetero-aggregation process for creating of such hetero-contacts needs to be investigated and controlled.In the first three years of the SPP 2289 the recursive approach is dominant, in which the material system of the hetero-aggregates is adapted to the process measurement technology and the characterization procedures of hetero-aggregates and their populations. Specific emphases are:- on the establishment of aerosol processes for the defined generation of hetero-aggregates, which can also be adapted to process diagnostics for the detection of mixing processes < 1 µm, - the derivation of particulate sampling trains from fast aggregation processes,- the establishment of tomographic methods for the characterization of hetero aggregates with sizes < 1 µm and - their mathematical framework for the description of hetero-aggregates as well as the establishment of process models and simulations covering mixture lengths < 1 µm.

• DFG Programme: Priority Programmes

Projects

• Agglomeration applying high intensity mixing (mechano-fusion) – An integrated approach towards the synthesis of tailored hetero-aggregates combining experiments with 2D and 3D structural characterization via image analysis and stochastic modeling (Applicants Peuker, Urs ;  Schmidt, Volker )
• Bipolar electrospray for the synthesis of defined hetero-aggregates: Process design and in situ diagnostics (Applicants Weber, Alfred ;  Will, Stefan )
• Charge-induced mixing of particles for the formation of structured materials and their comprehensive characterization (Applicant Lübbert, Christian )
• Coordination Funds (Applicant Mädler, Lutz )
• DeepMixing – Quantification of the mixing and interfacial hetero-characteristics of nanoparticle aggregates forming in an aerosol mixing zone (Applicants Mädler, Lutz ;  Rosenauer, Andreas )
• Formulation of hetero-aggregates in continuously-operated opposed jet fluidized beds (Applicants Bück, Andreas ;  Schmidt, Jochen )
• Hetero-aggregation of colloidal silica and carbon black in flames (Applicant Nirschl, Hermann )
• Hetero-aggregation of fine particles in supersonic flow for the tailor-made surface coating (Applicant Antonyuk, Sergiy )
• Hetero-aggregation of fluidized nanoparticles and solid-containing aerosol droplets (Applicant Tsotsas, Evangelos )
• Hetero-aggregation of nanoparticles in advective environments (Applicant Kronenburg, Andreas )
• Hetero-contacts in functional oxide aggregates: Descriptors of heterogeneity, aggregate design and process simulation towards nanostructured optical precursor materials (Applicants Wondraczek, Lothar ;  Wondraczek, Katrin )
• Heteroaggregate Formation Dynamics in the Dispersed Phase – Modeling, Simulation, and Experiments (Applicants Kaiser, Sebastian ;  Wlokas, Irenäus )
• Hybrid modelling of heteroagglomeration in gas-borne flows using CFD-DEM simulation and machine learning methods (Applicant Schilde, Carsten )
• Ion and electron conducting hetero-aggregates for electrochemical applications (Applicants Janek, Jürgen ;  Kwade, Arno )
• Laser-optical in situ detection and imaging of gas-borne heteroaggregate formation (Applicant Endres, Torsten )
• Quantification of the mixing zone and intensification of the mixing process of two nanoparticle producing flames for the design of hetero-contacts (Applicants Fritsching, Udo ;  Mädler, Lutz )
• Realization and analysis of jet-based direct mixing gas phase aggregation for the formation of hetero-aggregates with new properties (Applicants Kruggel-Emden, Harald ;  Schmidt, Eberhard )
• Spouted bed processing for structuring of conductive battery hetero-aggregates (Applicant Heinrich, Stefan )
• Synthesis of functional hetero aggregates in the gas phase (Applicant Wiggers, Hartmut )

• Spokesperson: Professor Dr.-Ing. Lutz Mädler