Due to their high energy density, lithium-ion batteries (LIBs) play a central role in the electrification of the energy system and have a wide range of applications. Given the increasing demand for this energy storage technology and the criticality of some raw materials used in LIBs, the need for effective recycling processes arises. Hence, the RecoPhos process, an innovative pyrometallurgical recycling process for LIBs, was developed at the Chair of Thermal Process Engineering. Here a valuable metal phase is obtained while lithium is separated via the gas phase. However, in order to prepare the LIBs for the RecoPhos process, the material needs to be pretreated. As part of this thesis, the properties of various pretreatment steps and the technical feasibility in connection with the RecoPhos process were examined through a comprehensive literature search. The aim is to create a metal phase that meets the requirements given by industry such as secondary metallurgy where low Cu, Mn and P contents are demanded. Based on the literature research and under the consideration of previous practical results, a multi-stage recycling process that enables a high black mass yield with low impurities was designed. However, the interactions between the process steps and the behavior of the fine black mass powder require further investigation. This process could significantly contribute to the effectiveness of the RecoPhos process and its practical application.