The present invention relates to an apparatus for separating smaller particles from larger particles by means of cyclonic separation. The apparatus comprises a feeding pipe (2) having an upper end (2a) for receiving material to be separated and defining a first channel (3) for transporting the material to a lower end (2b) of the feeding pipe, a separation chamber (5) having a curved wall (7), a first opening (6a) arranged at an upper end (5a) of the separation chamber, a second opening (6b) arranged at a lower end (5b) of the separation chamber, and the separation chamber (5) surrounds the feeding pipe (2) such that a second channel (8) is formed between the feeding pipe and the curved wall (7), an air inlet unit (12) arranged for supplying air to the second opening (6b) of the separation chamber, and an outlet unit (15) arranged for receiving air and separated material from the first opening (6a) of the separation chamber and to discharge the air and separated material. The curved wall (7) is conically shaped and tapers from the second opening (6b) to the first opening (6a), and the feeding pipe and the separation chamber are concentrically arranged.