05188708 is referenced by 14 patents and cites 110 patents.

A process for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine by partially delignifying the pulp to a K No. of about 10 or less and a viscosity of greater than about 13 cps; and further delignifying the partially delignified pulp with an effective amount of ozone for a sufficient time to obtain a substantially delignified pulp having a K No. of about 5 or less, a viscosity of greater than about 10, and a GE brightness of at least about 50%. The substantially delignified pulp may be brightened by the addition of a bleaching agent such as chlorine dioxide or a peroxide to obtain a final product having a GE brightness of at least about 65%, preferably above 70% to as high as 90%. Because of the absence of elemental chlorine in this sequence, filtrate from all stages but the chlorine dioxide stage (if used) can be recovered without sewering. Major environmental improvements are thus achieved.

Title
Process for high consistency oxygen delignification followed by ozone relignification
Application Number
311669
Publication Number
5188708
Application Date
August 26, 1991
Publication Date
February 23, 1993
Inventor
Allen Rosen
Lawrenceville
NJ, US
Michael A Pikulin
Bound Brook
NJ, US
Thomas P Gandek
Trenton
NJ, US
Bruce F Griggs
Columbia
SC, US
Agent
Pennie & Edmonds
Assignee
Union Camp Patent Holding
DE, US
IPC
D21C 9/18
D21C 9/153
D21C 9/147
D21C 9/14
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