Property Function to Compute the Dustiness of Powders

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The dustiness of a disperse solid can be understood as a property, which when handled in a gaseous environment, behaves similar to an aerosol, releasing the respective particle fraction of given quantity and size distribution. In general, this release of dust is undesirable because it might result in material loss and often is associated with an exposure of personnel involved or represents a risk of environmental pollution.The dustiness is therefore a product property, which might change along the process path, for example through comminution, agglomeration, classification or mixing of solids involved. Property functions which describe time variable dustiness integrated in dynamic processes as a function of the distribution of particle size, particle shape, and particle interaction during a certain handling, are to be determined as part of this project.For this purpose, experiments with laboratory equipment such as free fall in still air, moving in a rotating drum, dispersion, pressure surges method or airflow dispersion will be performed at very well defined boundary conditions and physically based models will be established. These models will be improved through the introduction of the so called Fractionated grade of release. Together with the description of time-dependent changes of the related strain-functions (apparatus properties) and rigidity-functions (material properties) this approach will help to better predict transient processes of dustiness. The discovered property functions will be evaluated for their suitability in practice in cooperation with project partners with respect to application.