The atmosphere particle kinetic model is a useful tool to analyze the particle kinetics as a function of the residence time. This model allows the quantification of various parameters in a RecoDust pilot plant for the pyrometallurgical purification of zinc-containing dusts. The main parameters are temperature, gas composition, gas velocity, particle size, particle composition and the particle inlet temperature. The size of the selected space is based on the size of the existing reactor. Fluid transport is solved in Eulerian framework, the dispersed phase as Lagrangian particle. As result the change of composition depending on the reaction rate in the particle for given parameters is received.