Douglas George Reid

US Patent:

20130269891, Oct 17, 2013

Filed:

Dec 19, 2011

Appl. No.:

13/996597

Inventors:

Douglas W. Reid - Marietta GA, US
John Atwood - Augusta GA, US
Scott Carmichael - Marietta GA, US
Daniel Connell - Canton GA, US

Assignee:

Akzo Nobel Chemicals International B.V. - Amersfoort

International Classification:

D21C 9/14

US Classification:

162 88

Abstract:

The invention is directed to a method for increasing brightness of pulp, wherein the method includes: contacting a pulp slurry with chlorine dioxide in a final D (ClO) bleaching stage; and adding a brightening additive to the final D bleaching stage after at least a portion of the chlorine dioxide has been consumed, in an amount sufficient to increase brightness of the pulp; wherein the brightening additive is an inorganic compound chosen from hypochlorous acid, one or more precursor compounds that form hypochlorous acid in said final D bleaching stage, or a mixture thereof.