Bleaching of Rice Straw Paper Pulp and Possibilities for Replacement of Sodium Hydroxide by Ammonium Hydroxide During the Extraction Stage
✍ Scribed by Heikal, Salwa O. ;Ibrahem, Atef A.
- Publisher
- Blackwell Publishing
- Year
- 2010
- Tongue
- English
- Weight
- 323 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0142-0356
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✦ Synopsis
Abstract
Bleaching of rice straw soda pulp was investigated under various conditions. The rate of the chlorination and hypochlorite reactions were studied; the best properties were attained by shortening the chlorination time to about 20 min. The extraction efficiency of ammonium hydroxide on chlorinated soda pulp was also investigated. The effectiveness of extraction can be deduced from the reduction of the kappa number, cuprammonium viscosity and the brightness obtained after the hypochlorite step. Extraction can be carried out with ammonium hydroxide instead of sodium hydroxide used in the conventional method. The strengths of unbleached and fully bleached pulps were evaluated. The fully bleached ammonium hydroxide extracted pulps were beaten faster and were usually stronger than the corresponding pulps extracted with sodium hydroxide.