Apparatus for fluidizing a pulverulent material in a stream of fluidizing gas includes a membrane through which the fluidizing gas can flow but the pulverulent material cannot, a first fluidizing gas gallery on a first side of the membrane, a second fluidized pulverulent material gallery on a second side of the membrane, a passageway out of the second gallery for the removal of fluidized pulverulent material therefrom, and apparatus for generating a signal indicative of fluidizing gas pressure inside the second gallery and controlling fluidizing gas pressure in the second gallery in response to the generated signal. The passageway accommodates a conveyor having multiple conveying sections. At least a first of the multiple conveying sections is located adjacent an inlet opening of a housing for the conveyor. The first conveying section is generally coextensive with the inlet opening. A conveyor drive mechanism is selectively engageable with the conveyor.