Förfarande för flotation av fyllmedel ur returpapper

摘要

A process for the separation of fillers and paper fibres by flotation is characterised in that following flotation of the printing ink the aqueous suspensions of pulp are treated as follows: 1. water-soluble salts of trivalent metal ions are added to bring the pH to between 4.5 and 9, and 2. flotation is carried out after the addition of from 0.1 to 8 g of anionic surfactants per kg of pulp.