Deinking process

Abstract

The present invention provides a process for deinking printed waste paper comprising the steps of: a) converting the printed waste paper to an aqueous pulp slurry in a pulper, where ink is detached from paper pulp; b) subjecting the pulp slurry to flotation in order to remove hydrophobic contaminants including ink from the pulp slurry, said flotation being carried out in the presence of a deinking chemical additive comprising modified silica obtained by treating hydrophilic silica particles with a hydrophobic organic liquid or modified metal silicate obtained by treating hydrophilic metal silicate particles with a hydrophobic organic liquid or a mixture of such modified silica and modified metal silicate. The present invention increases the yield of the flotation step without affecting the brightness of the flotation accept.

Dependencies are inferred from the claim text.