The knowledge about harmful elements, such as potassium, sodium, chlorine, fluorine and zinc in iron making processes is of high importance. These elements are volatile and build compounds which can harm the process, e.g. they can damage the refractory linings. Furthermore, the vaporization needs energy, which is then lost for melting the iron-bearing material. Of course, the blast furnace is the most important route for producing hot metal, but other technologies, such as the smelting reduction processes have huge benefits by means of usage of non-coking coal and iron ore fines. These aspects lead to environmentally beneficial processes. This thesis describes the most important smelting reduction processes, i.e. the COREX®, FINEX®, OxyCup, Hismelt and Romelt process. Furthermore, the thermodynamic behaviour of volatile elements (potassium, sodium, chlorine, fluorine and zinc) is described in typical atmospheres for iron making processes. As the FINEX® process is commercialized and processed by the steel producer Posco, a thermodynamic model was developed calculating the compounds in different stages of this smelting reduction process. Parameters, such as the hot gas cyclone temperature, the slag basicity and dust burner ratio were varied and the influences on the total output and enrichment of the elements are discussed.