Process to remove foreign bodies from a fluid suspension in a waste paper recovery process, has portion of floating foam from second-stage waste paper recovery tank skimmed and returned to the second-stage tank inlet

摘要

In a waste paper recovery process, foreign bodies are removed from a liquid suspension (S) of paper fibre in two sequential floatation stages (1, 2). Foam from the first tank (1) is skimmed and admixed to the fluid entering the second tank (2). A first (8') portion of the foam (8) generated in the second tank (2) is esp. returned to the inlet in the second tank (2). The non-removed portion (8) of foam generated in the second tank (2) no longer floats, so that the second floatation stage (2) is the last. The quantity of foam removed from the second stage is determined by a regulator assembly (11).