Date of Award

4-1991

Degree Name

Bachelor of Science

Department

Paper Science and Engineering

Abstract

The cross-flow filter was used to deink a 70% news and 30% coated section furnish. This has never been attempted before so the main objective was to determine if it would work. The secondary objective was to find the highest operating consistency possible. The filter can be used to remove ink, fines and filler from a stock suspension. The feed, accept and effluent samples were analyzed for percent ash, brightness, clark classification, Kajanni fiber length analysis and image analysis. The effluent had a 29.81% ash compared to the feed ash of 8.32%. The accept brightness was 42.9 while the feed brightness was 41.0. Image analysis showed that there were more ink particles per oven dry fiber in the effluent than in the feed or accepts. It also determined that the mean particle diameter in the effluent was 6.26 microns while the feed was 6.18 microns. The cross-flow filter was effective in removing ink and filler. One percent consistency was the highest operating consistency due to pump limitations. The cross-flow filtration concept has a great potential as a deinking method. Further work should be conducted to look at the screen design, stock temperature and feed consistency. Theoretically this device could be operated at any consistency if turbulent flow could be maintained.

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