Impurities i.e. larger printing ink particles, removal method for aqueous waste paper suspension, involves performing fractionation of waste paper suspension, removing printing ink particles and fractionating part of fine fraction

摘要

The method involves performing fractionation (4) of waste paper suspension (S) for forming fine fraction (F4) and rough fraction (G4), where the rough fraction disperses. Printing ink particles are removed from the waste paper suspension. A part of the fine fraction is fractionated by centrifugal energy fractionation (5) for forming light fractions (L5) and heavy fractions (S5). The formed heavy fractions are dispersed together with the rough fraction, where the light fraction or dispersed rough fraction is floated for removing printing ink particles.