@article{SterlingBreitungFaesKwade2024, author = {Sterling, David and Breitung-Faes, Sandra and Kwade, Arno}, title = {Improved energy transfer model for mechanistic scale-up of stirred media mills}, series = {Powder Technology}, volume = {444}, journal = {Powder Technology}, publisher = {Elsevier BV}, issn = {0032-5910}, doi = {10.1016/j.powtec.2024.119978}, pages = {14}, year = {2024}, abstract = {Wet-operated stirred media mills are commonly used in the field of fine and ultra-fine grinding. Depending on the application, there are different mill geometries, sizes and mill equipment materials of which the grinding chamber lining and the stirrer are made. Increasing energy prices demand an energy-efficient mill operation for a desired product, which can be achieved with mechanistic stress models. Here, besides the mill geometry and volume, the process parameters and various energy-transfer-coefficients are of importance. In this work, the impact of different mill equipment materials affecting the mill-related-energy-transfer-coefficients on performance prediction and scale-up using the advanced stress model are investigated. It was found that the mill-related-energy-transfer-coefficients as well as the improved grinding-media-energy-transfer-coefficients have a significant effect on the prediction precision of the comminution times and specific energies for chosen target particle sizes.}, language = {en} } @article{SterlingBreitungFaesKwade2023, author = {Sterling, David and Breitung-Faes, Sandra and Kwade, Arno}, title = {Experimental evaluation of the energy transfer within wet operated stirred media mills}, series = {Powder Technology}, volume = {425}, journal = {Powder Technology}, publisher = {Elsevier BV}, issn = {0032-5910}, doi = {10.1016/j.powtec.2023.118579}, pages = {17}, year = {2023}, abstract = {Wet-operated stirred media mills are commonly used in the field of fine and ultra-fine grinding. Depending on the application, there are different mill geometries and mill equipment materials of which the grinding chamber lining and the stirrer are made. Polyurethane and ceramics are frequently implemented materials. Besides the process-relevant effects such as cooling and wear prevention, an energy efficient mill operation is intended, which can be achieved, by using mechanistic stress models. Here, besides the mill geometry, the process parameters, various energy-transfer-coefficients are also determined. In this work, the effect of different mill equipment materials on the mill-related-energy-transfer-coefficient are investigated by experiments while operating different mills only with water and grinding media but without feed material. It was found that the mill equipment material has a significant effect on the power consumption and thus, the energy transfer within the mill as a result of friction between different materials.}, language = {en} } @article{SterlingSchonsBreitungFaesetal.2022, author = {Sterling, David and Schons, Didier and Breitung-Faes, Sandra and Kwade, Arno}, title = {Effects of axial grinding media distribution on the disc wear behavior of a stirred media mill}, series = {Minerals Engineering}, volume = {185}, journal = {Minerals Engineering}, publisher = {Elsevier BV}, issn = {0892-6875}, doi = {10.1016/j.mineng.2022.107702}, pages = {11}, year = {2022}, abstract = {Stirred media mills are commonly used process units for wet fine grinding and dispersing. During operation the grinding media and the feed material can cause wear to the process units of the stirred media mill. One typical representative of horizontal stirred media mills is the IsaMillTM, in which an internal classifier diverts the grinding media away from the discharge and implies a counteracting current force to the drag forces caused by the suspension flow. In this work, the disc wear of a pilot scale horizontal mill was investigated with regard to the axial grinding media distribution and other process parameters. In order to create quickly and well visible disc wear patterns, manufactured aluminum discs instead of the original polyurethane discs were specially used. For each set of operating parameters, a separate new pair of discs was installed. A radiometric densitometer was installed to measure the axial grinding media filling degree lengthwise to the M4 IsaMillTM. This method allows the determination of the local filling degree by correlation of the attenuation of gamma radiation from a Cs137 nuclide. The experiments showed that the disc wear per energy input increases with rising stress energy. With respect to the axial grinding media distribution, higher wear rates were observed in areas of increased grinding media filling ratios. As a result, it can be stated that the wear is a function of the local grinding media distribution and of the stress energy. In zones with a higher local grinding media filling degree, an increased disc wear is evident. Consequently, mills on a production scale could theoretically realize longer plant operating times and lower maintenance costs by securing a more homogeneous grinding media distribution.}, language = {en} }