Abstract: An apparatus for the treatment of flue gases is provided having an upright vessel with a generally cylindrical wall, two spaced cooling circuits, the inner surface of the wall, an inlet port for introducing flue gases into the vessel, a fan for forcing the introduced flue gases radially outwardly against the inner surface of the vessel, and an outlet port for outletting the dedusted flue gases. The force of the impact of the introduced flue gases against the inner surface of the vessel causes dust particles in the flue gases to remain on the inner surface while the dedusted gases are outletted through the outlet port. The outlet port has an inlet opening located substantially centrally of the vessel and spaced relatively closely below the fan. The upright vessel can be provided with a number of cooling fins which extend helically in the same direction as the direction of rotation of the fan.