US 12,286,751 B2
Oxygen treatment of high kappa fibers
Kevin M. Holtman, Appleton, WI (US); Jeffrey A. Lee, Neenah, WI (US); Daniel W. Sumnicht, Green Bay, WI (US); and Daniel E. Miller, Appleton, WI (US)
Assigned to GPCP IP HOLDINGS LLC
Filed by GPCP IP Holdings LLC, Atlanta, GA (US)
Filed on Dec. 11, 2021, as Appl. No. 17/548,503.
Claims priority of provisional application 63/134,222, filed on Jan. 6, 2021.
Prior Publication US 2022/0213648 A1, Jul. 7, 2022
Int. Cl. D21C 9/16 (2006.01); D21C 5/02 (2006.01); D21C 9/10 (2006.01); D21C 9/147 (2006.01); D21H 11/14 (2006.01)
CPC D21C 9/163 (2013.01) [D21C 5/02 (2013.01); D21C 9/1057 (2013.01); D21C 9/147 (2013.01); D21H 11/14 (2013.01); D21C 9/1036 (2013.01); Y02W 30/64 (2015.05)] 20 Claims
OG exemplary drawing
 
1. A method of making a high brightness papermaking pulp from recycled cellulosic fiber comprising:
(a) pre-treating a first recycled cellulosic fiber mix with oxygen;
said first recycled cellulosic fiber mix having a first high Kappa number greater than 20 prior to pre-treatment and a reduced Kappa number after pre-treatment that is lower than said first high Kappa number by less than 40% to form a pre-treated first recycled cellulosic fiber mix; and
(b) blending the pre-treated first recycled cellulosic fiber mix with the reduced Kappa number with a second recycled cellulosic fiber mix having a second Kappa number lower than the first high Kappa number of the first recycled cellulosic fiber mix to form a blended recycled cellulosic fiber mix; and
(c) oxidatively bleaching the blended recycled cellulosic fiber mix of step (b) in a bleaching vessel; and optionally
(d) reductively bleaching the blended recycled cellulosic fiber mix of step (c) to form a papermaking pulp for use as a furnish supply in a papermaking machine.