Iron and steel making requires a wide range of different raw materials which are significantly influencing process performance and demands a continuous optimisation of process routes also with respect to energy efficiency as well as environmental emissions. Steadily changing raw material prices and qualities, market situations and product variations are challenging integrated steel plant operators in production planning and cost optimization. To successfully counter this global market situation by the use of a simulation platform, the effort was taken to develop a holistic model library for optimization of integrated steel plants. This simulation platform – “m.simtop” is capable of a sophisticated depiction of any integrated steel plant setup and a wide range of calculation functionalities including optimization routines. In a detailed process analysis with m.simtop of a central European iron making route – consisting of a sinter plant, two blast furnaces including hot blast stoves and a hot metal desulphurisation ladle – simulation results were compared to operation data and showed highly accurate accordance. The special task of this process analysis was to specifically trace sulphur in the iron making production route – an environmentally and operationally crucial element. Due to this study generated simulation results delivered more insight on the sulphur distribution throughout the production process and robust figures which can be used for strategic operation planning are thus now available. In this summary the process chain, its depiction in m.simtop and related results are described.