JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 1984, Vol. 8 ›› Issue (01): 60-67.doi: 10.3969/j.jssn.1000-2006.1984.01.006

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PROPERTIES OF ITALIAN POPLARS IN PULPING AND PAPERMAKING——ALKALINE SULFITE-ANTHRAQUINONE PROCESS

Li Zhongzheng, Yao Guangyu, Zhang Datong & Xue Guoxin   

  1. Department of Chemical Processing of Forest Products
  • Online:1984-03-18 Published:1984-02-18

Abstract: In this paper. alkaline sulfite-anthraquinone (AS-AQ) pulping of Italian poplars was studied. The AS-AQ cooking liquor contains mostly sodium sulfite and sodium hydroxide. Results of the test indicate that the optimum ratio of sodium sulfite to the total alkali (all calculated as sodium oxide) is 0.85; the total amount of alkali is 18.6% (calculated as sodium oxide) and of anthraquinone 0.1%, with the ratio of liquor to chips being 4:1. The pulping time required at maximum temperature (175°C) is 220 minutes. The results of the cooking tests show that the total pulp yield is 57-60%, (in comparison with conventronal kraft pulp, yield of pulp is 6-8% higher) and a kappa number 40. Because of the mild pulping conditions and high pentosan contents of pulp, the brightness of unbleached pulp is higher and bleachability of pulp is also better. The breaking length of AS-AQ pulp handsheet is 8410m, its burst factor 60, its tear factor 72 and the folding strength 1498 (double folds). The properties of the physical-Mechanical strength of AS-AQ poplar pulp are equal to or slightly higher than those of kraft poplar pulp with the exception of a slightly lower tear factor. Therefore, AS-AQ pulping is regarded as a better process to produce high yield chemical pulp.