Optimised technologies for cryogenic grinding

The production of finest powders of viscoelastic and plastic materials is often very energy consumptive and therefore expensive or even not possible at ambient temperatures. At low temperatures, many materials become brittle so that they can be grinded more effectively. To achieve these temperatures, the materials are presently cooled with liquid nitrogen (lN 2), which is followed by high operation costs. At Fraunhofer UMSICHT, a low-temperature fine-grinding plant in technical scale was erected for research. Investigations for optimisation of cooling equipment resulted in the development of an innovative technology based on cooling technology. With this technology, the usage of lN 2 could be dramatically reduced. The contribution presents some results of our research in the fields mentioned above. A discussion of the new developments compared to the established techniques will complete the presentation.