Use of polymers in the recycled fiber washing/deinking process
AssigneeBetz Laboratories, Inc.
InventorsIrenee J. Philippe, Frank J. Sutman, Thomas E. Taggart, Mary B. K. Letscher, Michael A. Schuster, John C. Harrington, IV
Life of this patent
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Abstract
The present invention is directed to a method for increasing the retention on a washing/thickening device in an aqueous papermaking system. The method generally comprises adding to the furnish solids of the system an effective amount of a cationic polyacrylamide polymer.
Claims32
In the deinking of wastepaper in which ink particles are removed from an aqueous slurry of recycled fibers, followed by a washing and thickening step wherein said slurry is treated to further remove ink particles from said recycled fibers, the improvement comprising adding to the slurry an effective amount of cationic polyacrylamide polymer to increase the retention of recycled fibers in said washing and thickening step.
The method as recited in claim I wherein said cationic polyacrylamide polymer has a percent mole charge of from about 1 to 80%.
In the manufacture of recycled fibers which includes (1) the repulping of recovered paper, followed by (2) the removal of printing inks from fibers, followed by (3) the treatment of the fibers through a double nip thickener in order to further remove contaminants, and retain furnish solids, the improvement comprising adding to said slurry an effective amount of a cationic polyacrylamide polymer to increase the retention of said furnish solids on said double nip thickener.
In the deinking of wastepaper in which ink particles are removed from an aqueous slurry of recycled fibers followed by a highspeed washing and thickening step wherein said slurry is treated to further remove ink particles from said recycled fibers, the improvement comprising adding to said slurry an effective amount of cationic polyacrylamide to increase the retention of fumish solids in said high speed washing and thickening step.
A method of treating a pulp slurry containinq contaminant solid particles and fiber solids in a washing/thickening device of the type having a rotating roller and a wire in close proximity to said roller, said roller and said wire in combination, defining a nip interface therebetween, said method comprising:
- (1) treating said pulp slurry by adding a cationic polyacrylamide polymer thereto in an amount from about 0.025-25 pounds of said polymer per ton solids in said pulp slurry;
- (2) feeding said pulp slurry to said nip;
- and
- (3) forcing water and at least some of said contaminant solid particles from said pulp slurry through said wire along said nip interface to separate at least some of said contaminants from said slurry, whereby the amount of fiber solids remaining with said pulp after said step (3) is increased in comparison to untreated pulp slurries.
A method for increasing the amount of fibrous solids material retained in a pulp stock containing contaminant solid particles and said fibrous solids material treated in a washer/thickener device having a rotatable roller and a wire trained around a portion of said roller to define a nip location;
- said method comprising:
- (1) adding a cationic polyacrylamide polymer to said pulp stock in an amount of about 0.025-25 pounds of said polymer per ton solids in said pulp slurry;
- (2) feeding said pulp stock to said nip location and subjecting said pulp stock to centrifugal force thereat to express liquid and some of said contaminant solid particles through said wire.
Dependencies are inferred from the claim text.