DEM simulations of binary mixing of particles with different densities were conducted to study the influence of density ratio, impeller speed, and vessel speed on the particle dynamics and mixing performance in an intensive mixer. Six particles at different locations were tagged to discuss the influence of three factors on the particle trajectory and residence time in the impeller influence area. Velocity profile at a fixed point was analyzed to explore the local phenomena. Mean velocity fluctuation, coordination number and relative standard deviation (RSD) were used to quantify the mixing performance in the mixing process. It was found that the residence time increases with the increase of particle density, and the mean velocity fluctuation increases with the increase of impeller speed. The trajectory radius in impeller influence area and the vertical movement increase with the increase of impeller speed. Results obtained indicate that the mixing performance of binary particles with different density increases with the increase of impeller speed and vessel speed, while it decreases with the increase of density ratio. (c) 2021 Elsevier B.V. All rights reserved.