Optimal Deinking and Bleaching of Recycled Newspaper and Magazines to Produce Mechanical Printing Paper, 1990 Pulping Conference Proceedings

In this paper the deinking, blending and bleaching of old newspaper and groundwood containing magazines is studied. The laboratory work outlined investigates optimal deinking of these grades separately including the effect of various alkalies, peroxide and dispersants on pulp colour and cleanliness after washing and/or flotation. Next, pulp is blended in various proportions prior to hydrogen peroxide bleaching. Finally, sheet quality of furnishes made from bleached deinked pulp (BDIP) and bleached CTMP (BCTMP) blends is evaluated and compared to basesheets made from BCTMP and bleached kraft pulp (BKP).

Results indicate that for most quality parameters a 50% BDIP/5O% BCTMP blend offers equivalent performance to a 90%BCTMP/lO%BKP furnish typical of that used to make newsprint today. Further improvements in paper quality parameters to produce a sheet having nearly equivalent quality parameters to 75%BCTMP/25%BKP furnish typical of directory paper through supercalendered-A (SCA) grades were possible through additional bleaching and use of magazine paper versus newsprint.