Delignification and bleaching process and solution for lignocellulosic pulp with peroxide in the presence of metal additives
First Claim
1. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consisting of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
- C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding the pulp viscosity loss and degradation from cellulose oxidation, said pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a metal-containing additive whose metallic portion is selected from the group consisting of tin, titanium and vanadium; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7.
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Abstract
An improved peroxide based brightening and delignifying solution and process for liqnocellulosic pulp, characterized by selective delignification and pulp viscosity retention is disclosed. The process comprises maintaining a pulp slurry to a temperature between 40° C. and 120° C. for 0.5 hours to 8 hours. The slurry comprises lignocellulosic pulp; from 0.1% to 20% by weight based on O.D. pulp of peroxide; from 0.1% to 10% by weight based on O.D. pulp of a metal-containing additive whose metallic portion is selected from the group consisting of tin, titanium, and vanadium; and sufficient acid to maintain the f H of the slurry between about 1 and about 7. In a preferred embodiment of this invention, a tin additive is employed and the partially delignified and brightened pulp is further bleached with the unconsumed peroxide by adjusting the pH of the slurry to between 8 and 12 and maintaining the temperature of the slurry from 40° C. to 90° C. for 0.1 to 4 hours.
71 Citations
23 Claims
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1. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consisting of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
- C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding the pulp viscosity loss and degradation from cellulose oxidation, said pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a metal-containing additive whose metallic portion is selected from the group consisting of tin, titanium and vanadium; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- C. and about 120°
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8. In a process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, the improvement comprising employing an aqueous acidic slurry of lignocellulosic pulp having a pulp consisting of 3% to 50% and consisting essentially of lignocellulosic pulp;
- from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a metal-containing additive whose metallic portion is selected from the group consisting of tin, titanium and vanadiam; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7;
whereby that pulp viscosity loss and degradation are substantially avoided. - View Dependent Claims (9, 10)
- from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
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11. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising:
- forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding pulp viscosity loss and degradation from cellulose oxidation, said pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a tin-containing additive; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7; and
subsequent thereto adding sufficient base to adjust the pH of the pulp slurry to between about 8 and about 12; and
maintaining the temperature of the now alkaline pulp slurry between about 40°
C. and 90°
C. for a period of between about 0.1 and about 4.0 hours. - View Dependent Claims (12, 13, 14, 15)
- forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
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16. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consisting of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
- C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding pulp viscosity loss and degradation from cellulose oxidation, the pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a titanium-containing additive; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7. - View Dependent Claims (17)
- C. and about 120°
-
18. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising:
- forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency fo 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding pulp viscosity loss and degradation from cellulose oxidation, the pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a titanium-containing additive; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7; and
subsequent thereto adding sufficient base to adjust the pH of the pulp slurry to between about 8 and about 12; and
maintaining the temperature of the now alkaline pulp slurry between about 40°
C. and 90°
C. for a period of between about 0.1 and about 4.0 hours. - View Dependent Claims (19)
- forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency fo 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
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20. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
- C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding pulp viscosity loss and degradation from cellulose oxidation, the pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a vanadium-containing additive; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7. - View Dependent Claims (21)
- C. and about 120°
-
22. A process for delignifying and brightening lignocellulosic pulp for use in a paper-making process, comprising:
- forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
C. and about 120°
C. for a period of between about 0.5 hours and about 8 hours to delignify and brighten the pulp while substantially avoiding pulp viscosity loss and degradation from cellulose oxidation, the pulp slurry consisting essentially of lignocellulosic pulp;
from about 0.1% to about 20% by weight, based on O.D. pulp, of peroxide;
from about 0.1% to about 10% by weight, based on O.D. pulp, of a vanadium-containing additive; and
sufficient acid to maintain the pH of the pulp slurry between about 1 and about 7; and
subsequent thereto adding sufficient base to adjust the pH of the pulp slurry to between about 8 and about 12; and
maintaining the temperature of the now alkaline pulp slurry between about 40°
C. and 90°
C. for a period of between about 0.1 and about 4.0 hours. - View Dependent Claims (23)
- forming an aqueous acidic slurry of lignocellulosic pulp having a pulp consistency of 3% to 50% and maintaining the temperature of the pulp slurry between about 40°
Specification