During steel production, dusts are produced. Depending on the process route, the steel mill dust is composed with a high iron content and a low to high zinc content. Especially for dusts with a low zinc content it was necessary to develop a process for an economically treatment of the dust. The dust treatment called "RecoDust-Process" was developed at the Chair for Thermal Processing Technology at the Montanuniversitaet Leoben. For process optimisation and the development of new variants on an industrial scale, a detailed understanding of the processes in the reduction reactor is required. Measurements in the reactor are currently not feasible due to the high temperatures and dust loading of the gas. The development of the CFD simulation concept has been specifically designed for the RecoDust process. New numerical solutions have been developed for this purpose. The "Advanced Flamelet Equilibrium Hybrid DOM Model with Reactive Parcels and Mixture Fraction Displacement", which enables a gradual increase in the level of detail modelling of the calculations, allows design and parameter studies. The CFD simulation concept is divided into two blocks. The simulation block A with the atmospheric particle kinetics model APKM the application of studies on single particles. The APKM-Cube model was developed for studies of dust characteristics. In simulation block B, three-dimensional design studies will be considered, which will be investigated in individual description stages. Based on this work, patent application procedures were started. The concept of a new burner-reactor system is to be protected by patent. The patent, called ESR²-2Torus concept, is described in this thesis.