Impact of stress conditions on stirred media milling of a two component mixture

Abstract

Grinding of a material mixture is common in a variety of industries, even though, impacts on the multicomponent grinding result are not fully understood yet. Within this study, the wet fine grinding of a model system consisting of limestone quartz mixtures was investigated using a stirred media mill. The influence of the relative component grindability, as well as the component mixing ratio and the stress energy, which was adjusted by different stirrer tip speeds and grinding media sizes, were examined. The knowledge of the breakage behavior of the individual components within the mixture is the basis to understand the process. Hence, a new particle sample preparation method was developed; enabling the measurement of particle sizes separately for each component in the mixture. The results were interpreted according to the energy split factor approach, which was first conceived for ore grinding but also seemingly works for fine grinding purposes. Thus, the dependency of the component particle size was discussed in relation to the total as well as to the component specific energy. A significant effect of the mixing ratio and the adjusted stress energy on the single component grinding efficiency in mixture could be elucidated.