Process for modifying the properties of deinked waste paper pulps, especially the fiber classification and installation for carrying out the process

摘要

The invention relates to a process for producing paper raw material for high-grade printing papers from de-inked waste paper stock. According to the invention, the waste paper is first disintegrated, purified, floated and bleached, and the fibres of the de-inked waste paper stock thus obtained are comminuted by suitable means, so that the fibre length distribution approaches that of newly produced paper stock. In a further embodiment, the invention is characterised in that the waste paper is first disintegrated, purified, floated and bleached and the de-inked waste paper stock thus obtained is divided in the first step by suitable means into at least two fibre fractions which differ by the mean length of their fibres; subsequently, at least one of the fibre fractions is treated by suitable means in such a way that the mean length of the fibres of this fraction is significantly reduced; afterwards, at least two fibre fractions are recombined, so that a suspension is formed which has a fibre length distribution corresponding to that of a newly produced paper stock. IMAGE