Milling efficiency and wear behavior of silicon grinding media in autogenous stirred media milling

Abstract

This study investigates the wear mechanisms and milling efficiency of silicon as grinding media for autogenous stirred media milling. Fresh autogenous grinding media (aGM) showed an exponentially decreasing wear rate first, while becoming constant at longer grinding times. The wear rate of used aGM was constant throughout the whole milling experiment. Shape and size analysis revealed that chipping and abrasion mechanisms dominate the wear behavior. These mechanisms led to spheroidization of the aGM. The grinding media concentration was introduced as measure for the energy transfer from the stirrer to the product particles. This concept was used for weighting the specific energy consumption. Nanoparticles of around 150 nm were obtained with similar weighted specific energy consumptions, while used aGM performed most efficiently due to their spheroidized shape. Finally, spheroidized aGM still consumed more weighted specific energy than conventional grinding media. However, a direct comparison was difficult due to the different material properties of the grinding media.