ON THE MANUFACTURE OF PULP BY AMMONIUM SULPHITE PROCESS. (NO. 1)
On the cooking of Abies Sachaliensis by neutral ammonium sulphite process.
1953 Volume 7 Issue 5 Pages 316-323,394
Details
1953 Volume 7 Issue 5 Pages 316-323,394
It has been known that ammonia has a good penetrating power into wood systems and a good accelerating action of delignification when it is used in sulphite process as a base. As recently the cost of amminia has fallen so it may be used economically. If the destruction of cellulose and hemicelluloses is avoided by means of the neutral cooking with ammonium sulphite, it might be able to manufacture a pulp for paper making with high yield and good quarities
Abies Sachaliensis is cooked by neutral ammonium sulphite liquor for 5 hours at the cooking temperature, and the time to it is controlled in 1.5 hours in every case.The results of the experiments are shown as follows :
1. The practical temperatures by these neutral cookings lie in a range of 160-180°C, and the cooking at 165-170°C gives relatively good results.
2. In spite of the cooking performed in neutral, the destruction of cellulose and hemicelluloses takes place remarkably because of the relatively high cooking temperature in comparison with the ordinary sulphite process, and the yield of pulps is not so high as expected, but the yield of pulps is resulted 52-53%, showing its Roe number 10 and the holocellulose yield 92-93%.
3. To complete the pulping, the concentration of total SO2 of liquor is needed more than 5% at 165°C cooking and more than 2.6% at 170°C, but by the elongation of the cooking time makes complete pulping possible by 2.0-2.3% SO2 liquor.
4. At the waste liquor cooked with less than 5% SO2 liquor is acidic, the destruction of celluloses must be occured, so if it is controlled to keep neutral by alkali, the yield of pulps is sure to increase.
5. To complete the pulping, the SO2 consumption against absolutely dry chip is measured in the range of 10-30% in every case, and the amount of the lowest consumption corresponds to the SO2 consumption calculated in ordinary sulphite cooking.
6. A part of NH3 used is changed into a component of organic compounds inwaste liquor, which is not liberated by alkali.
7. The mechanical strength of the paper made of these pulps correspond to the strength of kraft paper.
