IMPROVED HYDROGEN PEROXIDE BLEACHING OF MECHANICAL PULPS USING CARBON DIOXIDE IN COMBINATION WITH SODIUM AND MAGNESIUM BASED ALKALI SOURCES
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.
bleaching brightness COD carbon dioxide hydrogen peroxide thermomechanical pulp
Louise Logenius Per Engstrand Anders Karlstrom Magnus Paulsson
FSCN (Fibre Science and Communication Network), Mid Sweden University, SE-85170 Sundsvall, Sweden Chalmers Industriteknik,SE-41288 Gothenburg, Sweden FSCN (Fibre Science and Communication Network), Mid Sweden University, SE-85170 Sundsvall, Sweden Ek
国际会议
16th International Symposium on Wood,Fiber and Pulping Chemistry(第十六届木材、纤维及制浆化学国际会议)
天津
英文
741-745
2011-06-08（万方平台首次上网日期，不代表论文的发表时间）