The RecoPhos process represents the basis of the experimental and numerical parts of this work. The heart of the process is an inductively heated packed bed reactor called InduRed. The aim of the RecoPhos process is to create a possibility, to process sewage sludge ash or steelworks slag energetically and materially. The recovery of the phosphorus contained therein, which is an important raw material for the fertilizer industry, is of particular interest. The chemical and physical properties of these oxide mixtures make the processing or recycling of the residues difficult. The dephosphorization of steel takes place through a series of reactions between the metal and slag phases, which reach equilibrium after a certain time. All relevant chemical reactions that have an influence on the transport of substances in the system were identified and their chemical kinetics were subsequently determined. The further motivation for this work lies in the development of a so-called "MultiRegion solver", in which the occurring physical phenomena in the interaction between different solid components as well as fluids with turbulent and laminar flow are solved and mapped.