A process and apparatus for manufacturing cement clinker in which pellets of raw material containing the necessary components for manufacturing the clinker are introduced into an apparatus where the pellets flow under gravity, successively through a preheating zone, a clinkering zone using a fluidized bed and a cooling zone. The pellets contain an amount of comminuted carbon determined so that its combustion produces an amount of heat within each pellet sufficient to carry out decarbonation of the material, taking into account the heat introduced by the hot gases passing upwardly through the apparatus. Decarbonation is completed at the base of the preheating zone and the pellets enter the clinkering zone at a temperature which is close to the clinkering temperature. Additional heat is supplied through burners within the clinkering zone.