FORFARANDE FOR FRAMSTELLNING AV CELLULOSA

摘要

Process for the preparation of cellulose pulp by treating a raw material of plant origin with water at a temperature of 110-170 degrees C under a pressure of 2-7 atm (gauge) for 0.3-4 hours, the ratio between the weight of the vegetable material and that of the water being 1 : 2-4. The plant material is simultaneously cooked and impregnated with a solution of nitric acid at 70-90 degrees C for 0.5-3 hours. This is followed by cooking of the material at 100-130 degrees C under a pressure of 1-4 atm (gauge) for 0.3-5 hours. The plant material is extracted with an alkali, and the gaseous cooking products are decontaminated by mixing them with air in a ratio of 1 : 0.5-1 by volume. The waste alkali obtained in the alkaline extraction stage is treated. The invention makes it possible to increase the cellulose yield and to improve the quality of the product considerably.