Experiments and simulations of a solids suspension process in a lab-scale stirred tank under turbulent conditions have been performed. Two impellers have been tested. The liquid-solid suspension consists of water and a mixture of glass and bronze particles. The simulations are Eulerian-Lagrangian with the liquid flow as the Eulerian part, being solved by means of a lattice-Boltzmann method combined with a large-eddy approach to turbulence modeling. Comparison with experimental visualizations indicates that the simulations are able to represent the start-up of the suspension process from a zero-velocity initial condition. Differences between experiment and simulation are observed near the bottom of the tank. The simulation data are used to highlight the collisional interaction between the two different types of solids, the role of baffles, and the effect of impeller type on the suspension process.