The paper analyses the dependence on process temperature of parameters that characterize the dense phase of a freely bubbling bed. Application of the bed collapse technique to beds of FCC, silica sand, and corundum in experiments covering a temperature field ranging from room level up to 700 degreesC demonstrates that the increase of interparticle forces at superambient temperatures leads to significant modifications of the fluidization dynamics. These include clear changes of the particulate phase voidage and dense phase velocity as well as of bubble hold-up. Changes induced in the partition of the total gas flow rate and, consequently, in the characteristics of the bubble phase of the fluidized bed are also discussed.