Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Gas – vapor or mist contact
Patent
1992-03-26
1994-09-13
Alvo, Steve
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Gas, vapor or mist contact
162 78, 162 89, D21C 9153
Patent
active
053465881
ABSTRACT:
A process for the chlorine-free bleaching of pulps in an aqueous suspension which comprises forming the suspension with a consistency of 3 to 20 mass percent; introducing into the suspension an ozone-containing gas having an ozone content of 20 to 300 g/m.sup.3 in an amount corresponding to at most 2 mass percent ozone calculated on dry pulp of the suspension during vigorous agitation of the suspension to form a reaction mixture; maintaining a pressure of the ozone-containing gas at a pressure of 1 to 15 bar during introduction into the suspension; and controlling reaction conditions during contact of the ozone-containing gas with the suspension to maintain a reaction temperature of 15.degree. to 80.degree. and a pH value of 1 to 8.
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Osawa et al, "The Action of Gaxous Reagents on Cellulosic Materials", TAPPI, vol. 46, No. 2 pp. 84-89.
Liebergott et al, "The Use of Ozone in Bleaching and Brightening Wood Pulps", Pulping & Bleaching Seminar, New Orleans (Nov. 1978).
Effect of pulp consistency and pH in ozone bleaching by Carl-Anders Lindholm.
Douglas W. Reeve and Paul F. Earl; "Mixing gases, water, and pulp in bleaching"; Jul. 1986 Tappi Journal; pp. 84-88 (Pulp Mixing).
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Gotzinger Gerhard
Hendel Peter
Hoglinger Anton
Kurz Friedrich
Peter Walter
Alvo Steve
Dubno Herbert
Lenzing Aktiengesellschaft
Myers Jonathan
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