Abstract
To promote the penetration, at the rapid cooking, we investigate the impregnation of cooking liquor and sodium hydroxide solution under pressure.
The cookings were carried out, after the Ca-bisulfite cooking liquor was pre-impregnated into chips (Red Pine) under pressure at 15 kg/cm2 in hour, or cookings were carried out by using the sulfurous acid, after the 2 %, 3 %, and 5 % sodium hydroxide solution was pre-impregnated under the same pressure and time,
The results of them were compared with usually rapil and normal times, Ca-base and Na-base cookings.
Results were as follows :
(1) In generally, the yields of the unbleached screening pulp were reduced at rapid cooking, soweN er, by impregnation of cooking liquor or sodium hydroxide solution under pressure, the yield of the screening pulp was increased, and the residue was decreased.
And, it is especially remarkable in latter.
(2) The accessibility for xantation reaction of bleached pulp, was improved by pre-impregnation of cooking liquor, or sodium hydroxide solution under pressure.
(3) The pitch content of unbleached pulp was reduced remarkably by pre-impregnation of sodium hydroxide solution under pressure.
