Studies on Fthe pulp of “Akamatsu” (Pinus densiflora S. et Z.) wood. 6.

On the sulphate digestion of the pine wood

Abstract

The yields and qualities of the sulphate pulp as changed by the composition of digesting liquor, maximum cooking temperature, time of digestion are studied.
Maine results are as follows.
1) For obtaining of the highest yield of pulp, the digestion for 2 hours at 170°C gives easy bleachable pulp, and digestion for 1 hour at 170°C and 2 hours at 160°C give hard unbleachable pulp.
2) For fast removal of lignin and less destruction of cellulose, the method of sulphate digestion is superior to the soda digestion.
3) If the ratio of Na²S in the digesting liquor is high the content of lignin in the pulp decreases.