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Method for bleaching alkaline wheat straw pulp with medium-concentration DEP (diethyl phthalate)

A wheat straw pulp and alkali process technology, applied in pulp bleaching and other directions, can solve the problems of large loss of strength of bleached pulp, poor brightness stability, and great environmental damage, and achieve the effects of significant environmental benefits, improved pulp brightness, and low pollution.

Inactive Publication Date: 2011-06-08
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, elemental chlorine-free (ECF) bleaching or total chlorine-free (TCF) bleaching technology for wood raw materials has a history of several decades and has good environmental benefits. Most of the non-wood pulp mills in my country use traditional CEH three-stage bleaching for wheat straw pulp. The strength loss of bleached pulp is large, the whiteness stability is poor, and it is harmful to the environment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Embodiment 1: 1) washing the unbleached alkaline wheat straw pulp with water until the washed water is neutral;

[0014] 2) carry out chlorine dioxide delignification to the wheat straw pulp after washing in the sealed container of section D, the mass concentration of wheat straw pulp is 10%, the chlorine dioxide consumption is 1.0% of the dry pulp quality, and the reaction time is 120min, and the reaction The temperature is 90°C, and the initial pH value of the bleaching solution is 1.0;

[0015] 3) washing the wheat straw pulp after delignification with water until the washed water is neutral;

[0016] 4) E-stage alkali extraction is carried out on the washed wheat straw pulp, the mass concentration of the wheat straw pulp is 10%, the amount of NaOH is 2.0% of the dry pulp mass, the temperature is 60° C., and the time is 60 min;

[0017] 5) washing the wheat straw pulp after alkali extraction with water until the washing water becomes colorless;

[0018] 6) carry ou...

Embodiment 2

[0020] Embodiment 2: 1) washing the unbleached alkaline wheat straw pulp with water until the washed water is neutral;

[0021] 2) carry out chlorine dioxide delignification to the wheat straw pulp after washing in the sealed container of section D, the mass concentration of wheat straw pulp is 10%, the chlorine dioxide consumption is 1.2% of the dry pulp quality, and the reaction time is 100min, and the reaction time is 100min. The temperature is 85°C, and the initial pH value of the float solution is 1.5;

[0022] 3) washing the wheat straw pulp after delignification with water until the washed water is neutral;

[0023] 4) E-stage alkali extraction is carried out on the washed wheat straw pulp, the mass concentration of the wheat straw pulp is 10%, the amount of NaOH is 2.1% of the dry pulp mass, the temperature is 60° C., and the time is 60 min;

[0024] 5) washing the wheat straw pulp after alkali extraction with water until the washing water becomes colorless;

[0025]...

Embodiment 3

[0027] Embodiment 3: 1) washing the unbleached alkaline wheat straw pulp with water until the washed water is neutral;

[0028] 2) carry out chlorine dioxide delignification to the wheat straw pulp after washing in the sealed container of section D, the mass concentration of wheat straw pulp is 10%, the chlorine dioxide consumption is 1.4% of the dry pulp quality, and the reaction time is 80min, the reaction The temperature is 80°C, and the initial pH value of the float solution is 2.0;

[0029] 3) washing the wheat straw pulp after delignification with water until the washed water is neutral;

[0030] 4) E-stage alkali extraction is carried out on the washed wheat straw pulp, the mass concentration of the wheat straw pulp is 10%, the amount of NaOH is 2.2% of the dry pulp mass, the temperature is 60° C., and the time is 60 min;

[0031] 5) washing the wheat straw pulp after alkali extraction with water until the washing water becomes colorless;

[0032] 6) carry out hydroge...

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Abstract

The invention discloses a method for bleaching alkaline wheat straw pulp with medium-concentration DEP (diethyl phthalate). The method comprises the following steps of: dilignifying unbleached alkaline wheat straw pulp with chlorine dioxide; extracting alkali from the dilignified wheat straw pulp with sodium hydroxide; and bleaching the wheat straw pulp with hydrogen peroxide so as to obtain wheat straw ECF (Elemental Chlorine Free) pulp with high whiteness and high physical index. The whiteness of the obtained wheat straw pulp can reach 79.32 percent ISO (International Standardization Organization), Kappa number is 4.3, and yield is about 85.37 percent; the wheat straw pulp bleached by the DEP is manufactured into hand sheets with the tensile index of 48.41 N.m / g, the tear index of 5.21 mN.m<2> / g and the burst index of 2.64 kPa.m<2> / g. Finished paper has high physical intensity, and can meet the requirement for manufacturing of cultural paper.

Description

technical field [0001] The invention relates to a medium-concentration DEP bleaching method for wheat straw pulp, in particular to a medium-concentration DEP bleaching method for alkaline wheat straw pulp. technical background [0002] At present, elemental chlorine-free (ECF) bleaching or total chlorine-free (TCF) bleaching technology for wood raw materials has a history of several decades and has good environmental benefits. Most non-wood pulp mills in my country use traditional CEH three-stage bleaching for wheat straw pulp. The strength loss of bleached pulp is large, the whiteness stability is poor, and it is harmful to the environment. Contents of the invention [0003] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a medium-consistency DEP for alkaline wheat straw pulp that improves the whiteness and stability of the pulp without affecting the strength of the bleached pulp. Bleaching method. [0004...

Claims

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Application Information

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IPC IPC(8): D21C9/14
Inventor 韩卿王伦
Owner SHAANXI UNIV OF SCI & TECH
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