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Method for reducing content of AOX in chlorine dioxide bleaching wastewater of bagasse pulp

A chlorine dioxide, bagasse pulp technology, applied in pulp bleaching, cellulose raw material pulping, textile and papermaking, etc., can solve the problem of not completely preventing AOX, and achieve the effect of reducing AOX content

Inactive Publication Date: 2016-02-24
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, my country's AOX emission standards are still far below the standards of developed countries in North America and Europe. Although the use of ECF bleaching of bagasse pulp can reduce the AOX content in bleaching wastewater and thus meet the national emission standards, ECF bleaching technology cannot completely prevent Formation of AOX during bleaching

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A method for reducing the AOX content of bagasse pulp chlorine dioxide bleaching wastewater, the operation steps are as follows:

[0021] 1. Hot water pre-extraction:

[0022] Without hot water pre-extraction process.

[0023] 2. Bagasse cooking:

[0024] Get 50g of the bagasse obtained in step 1, add it to the cooking tank and carry out the cooking process, add 250mL of distilled water, and add NaOH with a bagasse mass concentration of 10% after absolute hot water pre-extraction; the maximum reaction temperature is 160 ° C, and the heating time is 90 minutes, and the holding time at the highest temperature is 60 minutes. After cooking, bagasse pulp is obtained, and the bagasse pulp is dried to obtain bagasse dry bagasse pulp.

[0025] 3. Bleaching of bagasse pulp:

[0026] Get the bagasse pulp that step 2 makes and carry out bleaching operation, the absolute dry bagasse pulp 20g that step 2 makes is mixed with the bagasse pulp that mass concentration is 10%, adds th...

Embodiment 2

[0030] A method for pretreating bagasse to reduce the AOX content of bagasse pulp chlorine dioxide bleaching wastewater, the operation steps are as follows:

[0031] 1. Hot water pre-extraction:

[0032] Take 100 g of dry bagasse, add it to a cooking tank, add 500 mL of distilled water, the mass of NaOH added is 4% of the mass of dry bagasse, the reaction temperature is 120° C., and the reaction time is 30 min.

[0033] 2. Same as Step 2 of Example 1:

[0034] 3. Same as Step 3 of Example 1:

[0035] 4. Determination of AOX content in wastewater after bleaching:

[0036] Take the bleaching wastewater obtained after bleaching in step 3, and carry out AOX content measurement, and the AOX content measurement result is: 280.47mg.L -1 .

[0037] The AOX content of bagasse pulp bleaching wastewater was 280.47mg.L when the hot water pre-extraction temperature was 120°C and the reaction time was 30min -1 , and the AOX content of bagasse pulp bleaching wastewater without hot water...

Embodiment 3

[0039] A method for pretreating bagasse to reduce the AOX content of bagasse pulp chlorine dioxide bleaching wastewater, the operation steps are as follows:

[0040] 1. Hot water pre-extraction:

[0041] Take 100 g of dry bagasse, add it to a cooking tank, add 500 mL of distilled water, the mass of NaOH added is 4% of the mass of dry bagasse, the reaction temperature is 170° C., and the reaction time is 60 min.

[0042] 2. Same as Step 2 of Example 1:

[0043] 3. Same as Step 3 of Example 1:

[0044] 4. Determination of AOX content in wastewater after bleaching:

[0045] Take the bleaching wastewater obtained after bleaching in step 3, and carry out AOX content measurement, and the AOX content measurement result is: 213.10mg.L -1 .

[0046] The AOX content of bagasse pulp bleaching wastewater was 213.10mg.L when the hot water pre-extraction temperature was 170°C and the reaction time was 60min -1 , and the AOX content of bagasse pulp bleaching wastewater without hot water...

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Abstract

The invention discloses a method for reducing the content of AOX in chlorine dioxide bleaching wastewater of bagasse pulp. With bagasse as a raw material, bagasse is treated by using hot water pre-extraction technology; pretreated bagasse enters an elemental chlorine-free bleaching phase after a cooking and steaming procedure, and chlorine dioxide is used as a main bleaching agent; and after a section of chlorine dioxide bleaching procedure, wherein the usage amount of chlorine dioxide is 1.6% of the mass of absolute dry bagasse pulp, the content of AOX in bleaching wastewater is detected. Compared with the prior art, the method provided by the invention has the advantage that the content of AOX in bleaching wastewater is greatly reduced.

Description

technical field [0001] The invention relates to the field of clean pulping and papermaking, in particular to a method for reducing the AOX content of bagasse pulp chlorine dioxide bleaching wastewater. Background technique [0002] At present, my country's AOX emission standards are still far below the standards of developed countries in North America and Europe. Although the use of ECF bleaching of bagasse pulp can reduce the AOX content in bleaching wastewater and thus meet the national emission standards, ECF bleaching technology cannot completely prevent AOX generation during bleaching. With the continuous improvement of people's awareness of environmental protection, countries all over the world have stricter requirements on AOX emissions. From the perspective of world development trends, some developed countries have set the AOX emission limit at 0.1kg.t -1 Pulp, which is enough to prove the importance of controlling AOX, and the AOX emission limit in my country is st...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/14D21C3/22
CPCD21C9/14D21C3/22
Inventor 姚双全覃程荣聂双喜王双飞王志伟宋雪萍
Owner GUANGXI UNIV
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