Mechanical and thermal particulate interactions within beds composed of milli-metric size spherical beads rotated and heated by contact in a horizontal drum were simulated by means of commercial discrete element software EDEM. Mono-dispersed, gaussian-dispersed and bi-dispersed beds (two particle sizes or two particle densities) were considered. The mechanical segregation index (standard deviation of local bed compositions), the standard deviation of beads temperatures and the thermal segregation index (normalized standard deviation) were calculated for the four types of bed and for different baffles configurations. According to the simulations results, the temperatures dispersion was enhanced by the mechanical segregation and reached its highest values for the bi-density bed. Increasing the number and the length of the baffles considerably improved the overall heating rate and the thermal homogeneity of the considered beds, but influenced less the mechanical segregation within them. (C) 2019 Elsevier B.V. All rights reserved.