Abstract
This study was carried out to investigate the proper cooking conditions of soda-anthraquinone and alkaline sulfite-anthraquinone pulping of rice-straw, and get basic data f9r the use of rice-straw chemical pulp through the test of characteristics and physical properties of pulps made in the various cooking conditions From the experimental results , we can conclude as follows. In the soda-anthraquinone pulping of rice-straw, the optimum cooking conditions were 60 min. at $150^{\circ}C$ in the amount of caustic soda of 20% with the addition of anthraquinone(0.05%). And total yield, Kappa No. and brightness of pulp made in the condition above mentioned were 41.9%, 7.7 and 51.1 respectively. In the alkaline sulfite-anthraquinone pulping of rice-straw, the proper mixing ratio of cooking chemical(caustic soda : sodium sulfite) was 50:50. And the optimum cooking conditions were 60 min. at $150^{\circ}C$ in the amount of cooking chemical of 20% with the addition of anthraquinone(0.05%). At that time, the total yield, Kappa No, and brightness of pulp were 50.1%, 9.1 and 40.2 respectively. As a result, the alkaline sulfite-anthraquinone pulping was superior to the soda-anthraquinone pulping in the aspect of yield, but inferior in the viewpoints of Kappa No. and brightness. For the comparison of qualities of pulps made in the various cooking methods and conditions, the physical properties of four sorts of pulps were tested. As a result, soda-anthraquinone pulps were superior to alkaline sulfite-anthraquinone pulps in the various strengths excluding tear strength and brightness. On the other hand, pulps made in the condition of addition of cooking chemical of 20% were superior to pulps in the dosage of 15% in the aspects of all the strengths and brightness.
