Nalco Chemical Company

Carol S Greer

Peter E Reed

Manian Ramesh

Martha R Finck

Nancy P James

Linda S Wilkins

Ann M Capozzi

The present invention provides a method for removing secondary fiber contaminants from paper mill process waters comprising adding a polyvinyl chloride, a cationic polymeric coagulant and a polymeric flocculant to paper mill process waters containing secondary fiber contaminants in an amount sufficient to agglomerate the secondary fiber contaminants to larger particles sizes, and removing the secondary fiber contaminants from the process water by a dissolved air flotation clarification technique. The addition of particulate polyvinyl chloride in combination with a polymeric coagulant and flocculant prior to the DAF clarification process causes the contaminants to become preferentially coated with the polyvinyl chloride particles. This coating is what causes the subsequent removal of the secondary fiber contaminants in the DAF clarification process to be more effective.

Enhanced removal of hydrophobic contaminants from water clarification

Pitch in paper mills is controlled by treating paper mill systems with a water soluble polymer which contains a lower alkyl N-vinyl amide or a hydrolyzed lower alkyl N-vinyl amide.

Method for reducing pitch deposition using copolymer of N-vinyl acetamide

Diallyl dimethyl ammonium chloride/3-acrylamido-3-methyl-butanoic acid copolymers were prepared and found to be effective pitch control agents in papermaking systems.

Polydiallyl dimethyl ammonium chloride/3-acrylamido-3-methylbutanoic

A method for controlling pitch in papermaking systems which comprises the step of adding a hydrophobic polyelectrolyte copolymer coagulant to pulp and paper process water. The hydrophobic polyelectrolyte copolymer coagulant comprises diallyldimethylammonium chloride and a hydrophobic monomer selected from the group consisting of: quaternized dimethylaminoethylacrylates and quaternized dimethylaminoethylmethacrylates.

Hydrophobic polyelectrolyte coagulants for the control of pitch in pulp

Pitch control agents comprising a combination of water-soluble zirconium compounds and cationic polymers are described. Ammonium zirconium carbonate is preferred in combination with poly DADMAC and/or with EPI-DMA polymers.

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Lisle, IL, United States of America

Carol S Greer