The disclosure concerns apparatus for disintegrating waste paper and for sorting out fibers to be recovered from the suspension. There is a disintegrating chamber connected by a gravity feed discharge line to a drum type or vibration sorting device. A circulating member disposed in the disintegrating chamber rotates about an axis that is tilted at a small acute angle from the vertical. A screen located beneath the circulating member separates the disintegrating chamber from a discharge chamber beneath the screen. The screen sorts out coarser particles letting only finer suspension paticles pass into the discharge chamber. A first suspension discharge line communicates with the discharge chamber while a second suspension discharge line communicates with the disintegrating chamber immediately above the screen. Both discharge lines empty into each other and lead to the sorting device. Appropriate slides control flow through the two discharge lines. The preferred sorting device is a horizontally oriented, rotatable, perforated drum and the suspension delivered into the drum is screened, with the good suspension being collected and the coarse material being trapped inside the drum to exit from an end.