Planetary ball mills are well known and used for particle size reduction on laboratory and pilot scales for decades while during the last few years the application of planetary ball mills has extended to mechanochemical approaches. Processes inside planetary ball mills are complex and strongly depend on the processed material and synthesis and, thus, the optimum milling conditions have to be assessed for each individual system. The present review focuses on the insight into several parameters like properties of grinding balls, the filling ratio or revolution speed. It gives examples of the aspects of grinding and illustrates some general guidelines to follow for modelling processes in planetary ball mills in terms of refinement, synthesis' yield and contamination from wear. The amount of energy transferred from the milling tools to the powder is significant and hardly measurable for processes in planetary ball mills. Thus numerical simulations based on a discrete-element-method are used to describe the energy transfer to give an adequate description of the process by correlation with experiments. The simulations illustrate the effect of the geometry of planetary ball mills on the energy entry. In addition the imaging of motion patterns inside a planetary ball mill from simulations and video recordings is shown.

The increasing usage of electrical drive systems and stationary energy storage worldwide lead to a high demand of raw materials for the production of lithium-ion batteries. To prevent further shortage of these crucial materials, ecological and efficient recycling processes of lithium-ion batteries are needed. Nowadays industrial processes are mostly pyrometallurgical and as such energy and cost intensive. The LithoRec projects, funded by the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB), aimed at a realization of a new energy-efficient recycling process, abstaining high temperatures and tracing mechanical process-steps. The conducted mechanical processes were thoroughly investigated by experiments in a laboratory and within technical scale, describing gas release of aged and non-aged lithium-ion batteries during dry crushing, intermediates, and products of the mechanical separation. Conclusively, we found that applying a second crushing step increases the yield of the coating materials, but also enables more selective separation. This work identifies the need for recycling of lithium-ion batteries and its challenges and hazard potential in regards to the applied materials. The outlined results show a safe and ecological recycling process with a material recycling rate of at least 75%.