Application of the product related stress model for product dispersity control in dry stirred media milling

Abstract

Ground ultrafine and nano- materials are mainly produced by wet stirred media milling. The product related stress model can be used for the optimization of such grinding processes; the operational parameters can be related to the particle size or specific surface of the product. At the same time, for many materials dry grinding is required. During dry stirred media milling different problems arise, such as aggregation, agglomeration and particles sticking on the mill liners and on the grinding media. Consequently, the processes taking place in the mill and the effects of the operational parameters on the product properties are not as thoroughly known as in the case of wet stirred milling. In the present paper the application of the product related stress model for product dispersity control in dry batch stirred media milling is presented. Modifications of the models' main parameters such as stress intensity and stress number are introduced. The applications of the modified main parameters are presented for the optimization of the material and grinding media filling ratio, as well as functions for the characterization of the effect of the stress number and stress intensity on the product. With the introduced modifications, the product related stress model proved to be suitable for the characterization of dry batch stirred media milling.