METHOD OF REMOVING PRINTING INK FROM WASTE PAPER Russian patent published in 2021 - IPC D21C5/02 

FIELD: technological processes.

SUBSTANCE: invention relates to a method of removing printing ink from waste paper of predominantly office types, on which printing ink is applied at high temperatures using a laser printer and can be used primarily for production of writing paper. Set task is achieved by the fact that according to the method of removing printing ink from waste paper, which includes preparation of office waste paper with printing ink applied by a laser printer with subsequent dissolution in an alkaline medium and with addition of sodium hydroxide, sodium silicate, oleic acid, hydrogen peroxide, with further supply to flotation, wherein waste paper preparation takes place at moisture content of 5-15% in two steps, wherein at first step wastepaper is milled into particles with size of not more than 50×50 mm, at the second stage the waste papers are milled to fibers, which are then dissolved during 2-5 minutes.

EFFECT: reduced printing ink on the surface of fibers of waste paper by two-step grinding at moisture content of 5-15%, which increases the surface of interaction of fibers with chemicals with simultaneous reduction of preparation and disintegration time.

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