Flotation of a used paper fiber suspension, to separate impurities, takes part-flows from at least one flotation stage to be returned for flotation, to maintain a constant clean fiber suspension quality

摘要

To control the operation of a flotation assembly, to separate impurities from a suspension (S) of paper fibers and deliver a clean suspension (9), at least one part-flow (5,6,8,8') is taken from at least one flotation stage (1,2). The composition of the part-flow(s) differs from that of the inflows and throughput flows (4,7) and the overflows (3,8,8'). The part-flows are returned into the flotation assembly at least at one point. The part-flow volume is set according to the requirements for the clean suspension taken from the flotation assembly.