Mixing processes in agitated vessels with different stirring systems are simulated using a cell model. The model takes the fluid velocity and fluid turbulence, as well as the diffusion and the sedimentation velocity of the particles into account. The two- and three-dimensional behaviors of single particles and collectives of particles in the vessels, respectively, are discussed in terms of different aspects. The calculated concentration distributions are compared with some measurements from the literature. Furthermore, a user interface developed for the calculation program, is introduced.