A statistical mechanical simulation was developed and used to predict the macroscopic and microscopic behavior of fluidized beds. In particular, the model was used to study structural phenomena in liquid fluidized beds that contain a distribution of particle sizes and/or densities. Bed structural phenomena, such as density-based and size-based segregation, classification, expansion, inversion, and solids dispersion have all been successfully simulated. Experimental data for the segregation of glass beads of different sizes and different densities agree well with predictions made from the simulation (without adjustable parameters). Classification and dispersion simulations also show good agreement with experimental data.