The NESTRO three-fraction separator NDFS 14, which generates a pure PET fraction, transports the material to be classified to the classifier housing via an acceleration conveyor with controllable belt speed. A targeted air flow spreads the discharge parabola of the sorted material. Heavy and light fractions can now be captured separately before and after the rotating partition. The light fraction is blown upwards and captured in the upper area of the classifier by an infinitely adjustable suction hood before it is fed into the light fraction separator. The classifier operates in recirculating air operation, where 10% to 40% of the excess air is used for dust extraction. Appropriate measures in the classifier housing prevent any material from the light fraction from being carried into the heavy and target fraction flow.