Proper Selection of Polymeric Coagulant for Coated Broke Treatment and Consequences of Selection on Overall Wet End Chemistry, 1995 Papermakers Conference Proceedings

Jon E. Pearson M. R. St. John, Ph.D. Nalco Chemical Company Coagulants were shown to have significant variations in their molecular structure including; chemistry of the monomeric unit, charge density, molecular weight properties, and three-dimensionality. A number of observations can be made concerning the activity of polymeric coagulants for the treatment of coated broke. Different brokes were found to be treated most efficiently and effectively by polymers with different molecular structures. Consequently, the screening of a range of coagulants is necessary to select the treatment program best suited for a given broke. In the brokes examined, charge density was never found to differentiate the relative performance among polymers. It was shown that excellent retention could be achieved without reducing cationic demand to levels which might hurt wet end chemistry of the overall system. Mill experience showed that use of the proper coagulant for coated broke treatment could improve overall machine