Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Gas – vapor or mist contact
Patent
1994-10-27
1996-11-05
Alvo, Steven
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Gas, vapor or mist contact
162 76, 162 78, 162 60, D21C 902, D21C 9147, D21C 916
Patent
active
055713785
ABSTRACT:
Process for high pH metal ion chelation in pulps. Extraction and removal of detrimental metal ions and organic solvent extractives prior to delignification and bleaching is carried out on pulp, preferably kraft pulp, at a pH over 5, more preferably a pH over 6, most preferably a pH of 7-9. Aqueous pulp is first brought to a pH of about 3-6 to cause chelation and desorption of metal ions from the fiber phase of the aqueous pulp, and at the same time implementing air entrainment and evaporation. The pH is then raised, and the extractable species are removed by dewatering and washing the pulp.
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Appita 1991 6th International Symposium on Wood and Pulping Chemistry Proceedings vol. 1; "Controlling the Profile of Metals in the Pulp Before Hydrogen Peroxide Treatment"; J. Basta, et al.
Aticelca May 19-22, 1992, Bologna, Italy; "Developments of the Lignox Process"; Igerud, et al.
International Pulp Bleaching Contest, Jun. 11-14, 1991, Stockholm Sweden, "Reducing Levels of Aox--Part 3 Lowering of Kappa No. Prior to C1O.sub.2 Bleaching", Basta, et al.
Elofson Arne
Nordgren Arne
Alvo Steven
Hampshire Chemical Ltd.
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