cotton pulping making
Cotton pulping making used for papermaking mainly refer to cotton linter. Cotton linter refers to the portion of fiber that remains outside the cotton seed shell. The length of cotton staple fiber is shorter than that of skinned cotton fiber, but the maturity is equal, so the fiber content is high, so it is important goods and materials in the military, chemical and pharmaceutical industries.
At present, the production of cotton pulp in China is still high temperature, high alkali cooking and chlorine bleaching process is the main pulping yield, fiber degradation, and serious pollution, black liquor color, high concentration of organic matter, high PH value, the treatment is difficult. These problems have seriously hampered the development of domestic cotton pulp plants. Since the 1980s, the production of cotton pulp in the United States, Western Europe, Japan and other countries began to develop in the direction of oxygen-alkali pulping or alkali-hydrogen peroxide pulping. Our professional colleges and research institutes have also begun to explore this aspect. China is a large cotton producing country, and the quantity of cotton short wool is large, so we should solve the pulping problem of cotton short velvet. It is of great significance to China's paper industry.
In the aspect of cotton pulping, the oxygen alkali cooking process and alkali peroxide process are the main methods.
Compared with the traditional technology has the following characteristics:
- The cooking condition is mild, the quantity of alkali is low, the highest temperature of cooking is low, and the holding time is shortened.
- The yield and whiteness of the pulping were higher than that of the caustic soda method by more than 5% and the whiteness by more than 15%.
- The physical strength of pulp is high, the cracking length, breaking resistance, tear resistance: folding resistance have been improved.
- Better softness, alkali peroxide method can give superior softness of cotton linter pulp.
- Black liquor pollution load is low, black liquor CODCr and BOD5 can reduce40%, the PH value is lower.
- Light color, black liquor management difficulty greatly reduced.
All in all, cotton pulping making is popular, it is excellent for some uses. One thing should be paid attention is the environmental pollution problem.