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Method for carrying out elemental chlorine free (ECF) multistage bleaching on masson pine kraft pulp by using glyoxal

A technology for kraft pulp and masson pine, which is applied in the field of bleaching, can solve problems such as increasing bleaching effect, and achieve the effects of reducing pollution, increasing stability and improving use efficiency

Inactive Publication Date: 2011-09-21
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chlorine dioxide bleaching eliminates the production of polychlorinated biphenol compounds, greatly reducing the absorbable organic halides (AOX) and color in wastewater, but the effect of increasing the amount of chlorine dioxide to increase the whiteness of pulp is due to the generation of chlorite. affect the bleaching

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] 1) Wash unbleached masson pine kraft pulp with water to neutrality;

[0017] 2) carry out D to the washed masson pine kraft pulp in a sealed container 1 Section (the first stage chlorine dioxide bleaching) chlorine dioxide delignification, at first adjust the mass concentration that makes the masson pine sulfate pulp be 10%, then add the chlorine dioxide of 1.5% absolute dry weight of masson pine sulfate wherein, 0.4% glyoxal, 0.5% EDTA and 3.0% Na 2 SiO 3 React at 90°C for 60 minutes, and adjust the pH of the solution to 1.5 after the reaction is complete;

[0018] 3) Washing the masson pine kraft pulp after delignification with water until the washed water is neutral;

[0019] 4) Carry out E section (alkali extraction section) alkali extraction to the washed Pine masson kraft pulp, adjust the mass concentration of Pine masson kraft pulp to be 10%, add 2.5% of Pine masson kraft absolute dry weight wherein 1mol / L NaOH was reacted at 70°C for 60min;

[0020] 5) wash...

Embodiment 2

[0026] 1) Wash unbleached masson pine kraft pulp with water to neutrality;

[0027] 2) carry out D to the washed masson pine kraft pulp in a sealed container 1 Section (the first stage chlorine dioxide bleaching) chlorine dioxide delignification, at first adjust the mass concentration that makes the masson pine sulfate pulp be 10%, then add the chlorine dioxide of 1.5% absolute dry weight of masson pine sulfate wherein, 0.8% glyoxal, 0.5% EDTA and 3.0% Na 2 SiO 3 React at 70°C for 120 minutes, and adjust the pH of the solution to 2.0 after the reaction is complete;

[0028] 3) Washing the masson pine kraft pulp after delignification with water until the washed water is neutral;

[0029] 4) Carry out E section (alkaline extraction section) alkali extraction to the washed Pine masson kraft pulp, adjust the mass concentration of Pine masson kraft pulp to be 10%, add 2.8% of Pine masson kraft pulp wherein 1mol / L NaOH was reacted at 70°C for 60min;

[0030] 5) washing the pine...

Embodiment 3

[0036] 1) Wash unbleached masson pine kraft pulp with water to neutrality;

[0037] 2) carry out D to the washed masson pine kraft pulp in a sealed container 1 Section (the first stage chlorine dioxide bleaching) chlorine dioxide delignification, at first adjust the mass concentration that makes the masson pine sulfate pulp be 10%, then add the chlorine dioxide of 1.5% absolute dry weight of masson pine sulfate wherein, 1.2% glyoxal, 0.5% EDTA and 3.0% Na 2 SiO 3 React at 60°C for 140 minutes, and adjust the pH of the solution to 2.5 after the reaction is completed;

[0038] 3) Washing the masson pine kraft pulp after delignification with water until the washed water is neutral;

[0039] 4) Carry out E section (alkaline extraction section) alkali extraction to the washed Pine pine kraft pulp, adjust the mass concentration of Pine masson kraft pulp to be 10%, add 2.6% of pine kraft absolute dry weight therein 1mol / L NaOH was reacted at 70°C for 60min;

[0040] 5) washing t...

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Abstract

The invention provides a method for carrying out elemental chlorine free (ECF) multistage bleaching on masson pine kraft pulp by using glyoxal. The method is characterized by firstly adopting chlorine dioxide to carry out delignification on the unbleached masson pine kraft pulp; then utilizing sodium hydroxide to carry out alkali extraction on the masson pine kraft pulp after delignification; then using chlorine dioxide to carry out delignification on the masson pine kraft pulp; and finally adopting hydrogen peroxide to bleach the masson pine kraft pulp to obtain the masson pine ECF pulp with high whiteness and excellent physical indexes. The method has the following beneficial effects: the whiteness of the prepared masson pine kraft pulp can reach 88.36% ISO, the Kappa number is 5.02 and the yield is about 90.28%; and the masson pine kraft pulp bleached by DEDP is used for manufacturing the handsheet and the tensile index is 40.08N.m / g, the tear index is 12.80mN.m<2> / g and the burst index is 3.45kPa.m<2> / g, thus showing that the finished paper has better physical strength.

Description

technical field [0001] The invention relates to a bleaching method, in particular to a multistage bleaching method of glyoxal in masson pine kraft pulp without elemental chlorine. technical background [0002] At present, in order to meet the requirements of environmental protection, ECF (elemental chlorine-free bleaching) and TCF (total chlorine-free bleaching) bleaching are gradually replacing traditional chlorine-containing bleaching. Chlorine dioxide, as one of the main bleaching agents in the ECF bleaching process, is used in multi-stage bleaching of chemical pulp by many pulp mills, gradually reducing or replacing chlorination and chlorate bleaching. Chlorine dioxide bleaching eliminates the production of polychlorinated biphenol compounds, greatly reducing the absorbable organic halides (AOX) and color in wastewater, but the effect of increasing the amount of chlorine dioxide to increase the whiteness of pulp is due to the generation of chlorite. affect the bleaching...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/14D21C9/16
Inventor 韩卿刘杰
Owner SHAANXI UNIV OF SCI & TECH
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