CPL - Chalmers Publication Library

Improved hydrogen peroxide bleaching of mechanical pulps using carbon dioxide in combination with sodium and magnesium based alkali sources

Författare och institution:
L. Logenius (-); P. Engstrand (-); Anders Karlström (Institutionen för signaler och system, Reglerteknik); M. Paulsson (-)
Publicerad i:
16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC, 1 s. 741-745
Publikationstyp:
Konferensbidrag, refereegranskat
Publiceringsår:
2011
Språk:
engelska
Sammanfattning (abstract):
The pH-profile in the hydrogen peroxide bleaching stage of a Norway spruce thermomechanical pulp was levelled out by using carbon dioxide in combination with sodium or magnesium based alkali sources. Addition of carbon dioxide when magnesium hydroxide was used as the alkali source increased the pulp brightness with up to 1.5 brightness units when the bleaching was performed at 70 °C. When the temperature was increased from 70°C to 90 °C the brightness was increased with about two brightness units, addition of carbon dioxide increased it further. The residual hydrogen peroxide and the chemical oxygen demand (COD) levels were not affected as a consequence of the carbon dioxide addition. In the experiments where sodium hydroxide was used as the alkali source, addition of carbon dioxide lowered the pH that resulted in a decreased COD level, a slightly lower brightness level and, to some extent, an increased residual hydrogen peroxide level.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
TEKNIK OCH TEKNOLOGIER ->
Elektroteknik och elektronik ->
Reglerteknik
Nyckelord:
Bleaching, Brightness, Carbon dioxide, COD, Hydrogen peroxide, Thermomechanical pulp
Postens nummer:
166133
Posten skapad:
2012-11-15 15:40

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