PREPARATION OF KRAFT PULP: IMPREGNATION WITH SPENT ALKALINE COOKING LIQUOR, HEATING, AND SUBSEQUENT DELIGNIFICATION WITH FRESH ALKALINE COOKING LIQUOR

摘要

Processes for preparing kraft pulp are disclosed. The processes include pretreating cellulosic material or chips with spent cooking liquor at the temperature of about 20 to 100 DEG C, followed by heating the impregnated chips at the temperature of from about 120 to 180 DEG C, followed by digestion of the lignin with white liquor, which is facilitated by using this pretreatment process.