Property Function to Compute the Dustiness of Powders

分散固体的含尘度可以理解为一种性质，当在气态环境中处理时，其行为类似于气溶胶，释放给定数量和尺寸分布的相应颗粒部分。一般来说，粉尘的释放是不希望的，因为它可能导致材料损失，并且通常与相关人员的暴露有关，或者代表环境污染的风险。因此，粉尘是一种产品性质，其可能沿着工艺路径改变，例如通过所涉及的固体的粉碎、附聚、分类或混合。作为本项目的一部分，将确定描述动态过程中随时间变化的含尘度的属性函数，该属性函数是颗粒尺寸分布、颗粒形状和颗粒相互作用的函数。为此，将使用实验室设备进行实验，例如在静止空气中自由落体、在旋转滚筒中移动、分散、将在非常明确的边界条件下进行压力波动法或气流扩散，并建立基于物理的模型。这些模型将通过引入所谓的分级释放来改进。与相关的应变函数（设备属性）和刚度函数（材料属性）的随时间变化的描述一起，这种方法将有助于更好地预测粉尘的瞬态过程。将与项目合作伙伴就应用问题合作，对所发现的属性功能进行评估，以确定其在实践中的适用性。

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.