Effects of System Closure on Retention and Drainage Aid Performance in TMP Newsprint Manufacture, 1998 Papermakers Conference Proceedings

What will happen to the effectiveness of presently available retention and drainage aid systems in newsprint mills as we increase the degree of system closure? Will they continue to function as well as they do now, or will it be necessary to develop new, more effective ones as the degree of white water recycling increases? The performances of five different retention and drainage aid systems were determined at three degrees of closure in TMP newsprint. Three different levels of fresh water usage were employed in the study. For 55 and 20 m /t, samples of pulps and paper machine white waters were 3 taken from existing TMP newsprint mills. For 3 m /t, samples of white water were prepared in our system closure pilot plant. 3 The retention aid systems consisted of: bentonite/anionic polyacrylamide (Organosorb/Organopol), PEO/phenolic resin, PEI (Polymin SKA), poly (DADMAC), and chitosan. Furnishes with more highly recycled white waters had higher cationic demands. Results suggest that the performances of cationic polymers are impaired by system closure; on the other hand, those of the nonionic flocculants were relatively unaffected or improved.