Process for separating gases from a fluidized gas/solid mixture, comprising at least one injection of gas and optionally at least one injection of solids into and at least one discharge of solids from said fluidized bed, a discharge for gas from the mixture characterized in that it comprises a step of separating the solids entrained by the gas by means of an internal placed in that portion of the fluidized mixture where the voidage is greater than 0.7, occupying less than 10% of the free cross section of the bed.