Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Gas – vapor or mist contact
Patent
1989-05-05
1990-09-25
Alvo, Steve
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Gas, vapor or mist contact
162 67, 162 89, D21C 914, D21C 9153
Patent
active
049591240
ABSTRACT:
A method of enhancing the quality of a pulp which has been subjected to a chlorine-based bleaching agent, by subjecting the chlorinated pulp to ozonation prior to an extraction stage in the bleaching sequence. The improved pulp of the present invention includes reduction of total organically bound chlorine residues in the wood pulp and adsorbed organic halides (AOX) in the effluent, and has good brightness and viscosity. The advantages of the present invention may be accomplished by means of a bleaching sequence that employs as few as four stages, namely DZED with attendant relatively lower capital investment than heretofore possible.
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Alvo Steve
International Paper Company
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