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Bleaching method of bagasse pulp

A technology for bagasse pulp and absolutely dry pulp is applied in the field of bleaching bagasse pulp, which can solve the problems of reduced bleaching effect, poor brightness stability, and large environmental pollution, and achieves improved economic benefits, good brightness stability, and high hygiene standards. Effect

Inactive Publication Date: 2005-01-05
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the bleaching of bagasse pulp in my country is still mainly based on Ca(OCl) 2 Single-stage bleaching and C-E-H bleaching are only carried out by individual mills. A series of problems such as low bleaching yield, low whiteness, poor whiteness stability, poor paper strength, and large environmental pollution have not been solved.
[0005] However, research and practice have shown that H 2 o 2 Poor stability, easy to decompose into H 2 O and O 2 and reduce the bleaching effect, so it is called invalid decomposition; and, H 2 o 2 Bleaching is severely constrained by two classes of metal ions

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Specific bleaching methods;

[0024] 1. Use H 2 SO 4 Pretreatment of unbleached pulp; H 2 SO 4 The dosage is 0.5% of the dry pulp weight, the treatment temperature is 60°C, and the treatment time is 10 minutes;

[0025] 2. Add H separately 2 o 2 , MgSO 4 and DTPA, based on the weight of dry pulp, the addition amounts are: H 2 o 2 The addition amount is 0.03g / g absolute dry pulp, adding MgSO 4 Make Mg 2+ The addition amount is 3×10 -4 The addition amount of g / g dry pulp and DTPA is 5×10 -4 g / g absolute dry pulp;

[0026] 3. Add NaOH and Na 2 SiO 3 , the sum of the weights of the two is 5% of the dry pulp weight;

[0027] 4. Join O 2 to bleach; keep O 2 The pressure is 0.8Mpa, the bleaching temperature is 60°C, and the treatment time is 50 minutes.

Embodiment 2

[0029] 1. Use H 2 SO 4 Pretreatment of unbleached pulp; H 2 SO 4 The dosage is 1.0% of the dry pulp weight, the treatment temperature is 72°C, and the treatment time is 18 minutes;

[0030] 2. Add H separately 2 o 2 , Mg(NO 3 ) 2 and DTPA, based on the weight of dry pulp, the addition amounts are: H 2 o 2 The addition amount is 0.04g / g absolute dry pulp, adding Mg(NO 3 ) 2 Make Mg 2+ The addition amount is 5×10 -4 The addition amount of g / g dry pulp and DTPA is 18×10 -4 g / g absolute dry pulp;

[0031] 3. Add NaOH and Na 2 SiO 3 , the sum of the weights of the two is 7% of the dry pulp weight;

[0032] 4. Join O 2 to bleach; keep O 2 The pressure is 1.1Mpa, the bleaching temperature is 80°C, and the treatment time is 70 minutes.

Embodiment 3

[0034] 1. Use H 2 SO 4 Pretreatment of unbleached pulp; H 2 SO 4 The dosage is 1.6% of the dry pulp weight, the treatment temperature is 80°C, and the treatment time is 25 minutes;

[0035] 2. Add H separately 2 o 2 , MgCO 3 and DTPA, based on the weight of dry pulp, the addition amounts are: H 2 o 2 The addition amount is 0.06g / g absolute dry pulp, adding MgCO 3 Make Mg 2+ The addition amount is 7×10 -4 The addition amount of g / g dry pulp and DTPA is 30×10 -4 g / g absolute dry pulp;

[0036] 3. Add NaOH and Na 2 SiO 3 , the sum of the weights of the two is 8% of the dry pulp weight;

[0037]4. Join O 2 to bleach; keep O 2 The pressure is 1.5Mpa, the bleaching temperature is 100°C, and the treatment time is 90 minutes.

[0038] After the bagasse pulp is bleached by the method of Example 2, the result is: the yield of bleached pulp is 95.3%, the whiteness reaches 79.26% ISO, the kappa value is 2.79, and the viscosity is 900.66ml / g, which are significantly higher...

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PUM

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Abstract

The invention discloses a bagasse pulp bleaching method, including the steps: preprocessing unbleached pulp by H2SO4 to reduce the content of transition metal ions; adding in a proper amount of H2O2, Mg2+ and DTPA; adding in NaOH and Na2SiO3; adding in O2 for bleaching. The invention can make the Soda-AQ processed bagasse pulp reach 79.26% ISO whiteness by single-stage bleaching, the experiment verifies that the whiteness reaches 79.92% ISO whiteness, reaching the level of C-E-H tri-stage bleaching.

Description

technical field [0001] The invention relates to a method for bleaching bagasse pulp, in particular to a method for bleaching bagasse pulp with the combined action of oxygen and hydrogen peroxide under pressurized conditions. Background technique [0002] my country is a big grass pulp country. The bleaching process and technology of straw pulp are very backward, and most factories still use the traditional Ca(OCl) 2 Perform single-stage bleaching (ie H bleaching), and a few straw pulp mills use Cl 2 (C), NaOH(E) and Ca(OCl) 2 (H) A typical C-E-H three-stage drift. H single-stage bleaching, bleached pulp has low brightness (only about 70% ISO), poor brightness stability (easy to return to yellow), low pulp yield, and poor strength. C-E-H three-stage bleaching can increase the whiteness of bleached pulp to 80% ISO, and the strength and whiteness stability are also slightly improved, but equipment investment, plant area, and consumption of water, electricity, and medicines ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/10
Inventor 邱玉桂张树滨包永来
Owner SOUTH CHINA UNIV OF TECH
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