Nowadays, one of the aims of chemical nonlinear dynamics is to understand the governing forces behind precipitate pattern formation in reactive media. In our study, we are investigating precipitate pattern formation and separation in confined geometry where fluid convection is coupled with a precipitation reaction leading to the formation of solid particles. A colloidal intermediate state forms first, followed by the appearance of solid phase with nonlinearity arising from the precipitation growth. Because of the particle density and their continuous growth, the interaction between the fluid and the solid phase cannot be neglected. The fluid motion, characterized by the appropriate flow and concentrations fields, is described by solving the Navier-Stokes equation using the PIMPLE method of OpenFOAM software package. The trajectories of solid particles are followed by Lagrangian particle tracking. With this model we are capable of not only reproducing experiments, but also calculating data which is experimentally difficult to measure.