The total amount of solid particles as a parameter influencing the viscosity and the foaming properties of the slag was investigated. In this context, the amount of these particles for different process conditions was quantified. In addition, the effect of the process conditions on the total amount of the particles was studied. More specifically, some parameter studies were carried out in oder to determine the influence of chromium oxide (Cr2O3) content, calcium oxide (CaO) content, basicity and temperature on the total amount of solid particles. The interactions between the process conditions were also taken into account.