Claims
- 1. Process for the delignification of lignocellulosic substances, comprising:
- treating a lignocellulosic material in a first stage with an inorganic acid at a pH of between about 1 and about 4, in the presence of diethylenetriaminepentaacetic acid or an alkaline metal salt of diethylenetriaminepentaacetic acid to sequester metal ions,
- treating said lignocellulosic material in a second stage with a quantity of hydrogen peroxide of between about 0.5 and about 2 grams per 100 grams of dry lignocellulosic material in which the liquor to wood weight ratio is kept between about 1:1 and about 2:1 in an alkaline medium containing sodium hydroxide at an initial pH of between about 12 and about 13 to accelerate delignification of said lignocellulosic material and retard carbohydrate degradation during subsequent digestion,
- water washing said treated lignocellulosic material of said second stage, and
- digesting said water washed lignocellulosic material in a kraft digestion to produce a paper pulp.
CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation of Application Ser. No. 06/762,724, filed Aug. 5th, 1985, and now abandoned, the entire specification of which is incorporated herein by reference.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4050981 |
Jamieson et al. |
Sep 1977 |
|
4462864 |
Carles |
Jul 1984 |
|
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Country |
678022 |
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BEX |
873649 |
Apr 1953 |
DEX |
58-91884 |
Jan 1983 |
JPX |
8091884 |
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JPX |
Non-Patent Literature Citations (2)
Entry |
EUCEPA Symposium "The Delignification Methods of the Future", vol. II, No. 7-18 Helsinki, Jun. 2-5 1980 (Pekkala p. 14/1 to 14/19). |
Przeglad Papierniczy, vol. 33, Aug. 1977, W. Mroz and W. Surewicz, "Modification of the Kraft Pulping Process aimed at Improving the Color of the Pulp" (pp. 277 to 280). |
Continuations (1)
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Number |
Date |
Country |
Parent |
762724 |
Aug 1985 |
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