Massaframställning genom uppslutning av en blandning av cellulosabaserat returmaterial och råträ

摘要

A process for the production of a waste-based cellulosic pulp useful for the manufacture of paper and paperboard whether used in admixture with virgin pulp or as the sole pulp component, comprising the steps: a) digesting a waste cellulosic material in an aqueous cooking liquor having a pH lower than about neutral and containing free and/or bound SO2 and a base; b) carrying out digestion with the exclusion of atmospheric oxygen at an elevated temperature, such as within the range about 120 to 160 DEG C and at a correspondingly increased pressure; and c) recovering the resulting cellulosic pulp.