FORFARANDE FOR UPPARBETNING AV HOGVERDIGT RETURPAPPER GENOM KOKNING

摘要

The invention concerns processing of high grade waste paper especially for printed waste paper containing wood and wet strength agents. In order to provide satisfactory digestion of such paper, it is digested under pressure in a digester at a temperature above 100 DEG C (preferably 110 to 140 DEG C) and at a density range from 20 to 50% under acid and/or alkaline conditions. The digested paper is then diluted and mixed with flotation chemicals. This may be followed by a two stage flotation process.