FORFARANDE FOR FRAMSTELLNING AV OBLEKT SULFITCELLULOSA MED HOG LJUSHET, RENHET OCH STYRKA ELLER BLEKT CELLULOSA AV KVISTMASSA

摘要

Knots separated from sulphite cellulose produced by a sulphite cellulose cooking process are converted to unbleached sulphite cellulose by first separating and defibrating the sulphite knots and then treating the defibrated sulphite knots with oxygen under pressure in an alkaline milieu at an elevated temperature. The resultant cellulose may be bleached by itself, or mixed with sulphite cellulose produced from knot-free cellulose pulp for bleaching therewith.