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Improved paper pulp bleaching process

A pulp bleaching and process technology, applied in pulp bleaching, bleaching agent addition, pulp raw material addition process, etc., can solve the problems of reducing pulp yield and pulp strength, damaging pulp fibers, increasing production costs, etc.

Inactive Publication Date: 2008-03-05
XINJIANG BOHU REED IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The papermaking waste liquor from non-wood pulping—black liquor, is basically treated through the alkali recovery process of the combustion method. The pulp fiber is damaged, the pulp yield and pulp strength are reduced, the waste water cannot be reused, and it can only be treated by the middle-stage water purification equipment, which increases the production cost
Reed pulp bleaching adopts CEH bleaching process, that is, chlorine (C) bleaching technology is used in the first stage, alkali (E) extraction lignin bleaching technology is used in the second stage, and hypochlorite (H) bleaching technology is used in the third stage. The bleaching stage (middle stage) wastewater contains carcinogens such as dioxin, which not only greatly endangers the environmental quality, but also poses a threat to human health, and these chlorine and chlorine-containing bleaching agents damage the pulp fibers, resulting in pulp washing degree and high yellowing value, which reduces the pulp yield and pulp strength

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Embodiment 1: bleach reed pulp with bleaching process of the present invention, its step is as follows:

[0013] 1. The first stage: Oxygen delignification is used for bleaching, the pulp concentration is 8%, the temperature is 130°C, the oxygen dosage is 4.5kg / t pulp with a purity of 100%, the NaOH dosage is 4kg / t pulp, and magnesium sulfate is 1.0%. Wash off the residue with water;

[0014] 2. The second stage: the concentration of reed pulp after washing is 16%, the amount of biological enzyme added is 80g / T slurry, the slurry temperature is 80°C, the pH value of the slurry is 12, the hardness of the slurry is potassium permanganate value 8 for 4 hours, and then washed with water to remove the reaction residue.

[0015] 3. The third stage: bleaching with calcium hypochlorite, slurry concentration 15%, bleaching rate 4.5%, temperature 45°C, time 4.5 hours, pH value after bleaching 7.5, wash off the reaction residue with water.

[0016] After testing: the cleaning de...

Embodiment 2

[0020] With bleaching process bleaching reed pulp of the present invention, its step is as follows:

[0021] 1. The first stage: Oxygen delignification is used for bleaching, the pulp concentration is 14%, the temperature is 125°C, the oxygen dosage is 1.8kg / t pulp with a purity of 100%, the NaOH dosage is 1.5kg / t pulp, and magnesium sulfate is 0.3%. , wash the residue with water;

[0022] 2. The second stage: the concentration of the reed pulp after washing is 5%, the amount of biological enzyme added is 40g / T slurry, the slurry temperature is 50°C, the pH value of the slurry is 10, and the hardness of the slurry is potassium permanganate 4, the time is 0.5 hours, and then washed with water to remove the reaction residue.

[0023] 3. The third stage: bleaching with calcium hypochlorite, slurry concentration 8%, bleaching rate 1.8%, temperature 35°C, time 1.5 hours, pH value after bleaching 8, wash off the reaction residue with water.

[0024] After testing: the cleaning deg...

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PUM

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Abstract

The invention discloses an improved pulp bleaching technique for reed pulp paper-making, which comprises: first, using deoxylignin for bleaching, wherein, slurry concentration 8-20%, temperature 85-130Deg, oxygen consumption quanity 1-4.5Kg per ton slurry, NaOH consumption quanity 1-4Kg per ton slurry, and MgSO4 consumption quantiy 0.1-1.0%; second, using biological enzyme for bleaching, wherien, enzyme adding quanity 20-80g per ton slurry, temperature 30-80Deg, slurry concentration 5-16%, pH value 5-12, slurry hardness 2-8(KMnO4), and time 0.5-4h; third, adding hypochlorite for bleaching. This invention can reduce bleachability and back-yellow value, improves yield and slurry hardness, and decreases pollution to environment.

Description

technical field [0001] The invention belongs to a pulp bleaching process, in particular to an improved pulp bleaching process for reed pulp papermaking. Background technique [0002] In our country, many paper mills use non-wood pulp to make paper, such as: use wheat straw pulp, straw pulp or reed pulp to make paper. The papermaking waste liquor from non-wood pulping—black liquor, is basically treated through the alkali recovery process of the combustion method. The pulp fiber is damaged, the yield of the pulp and the strength of the pulp are reduced, and the waste water cannot be reused, so it can only be treated by the middle-stage water purification equipment, which increases the production cost. Reed pulp bleaching adopts CEH bleaching process, that is, chlorine (C) bleaching technology is used in the first stage, alkali (E) extraction lignin bleaching technology is used in the second stage, and hypochlorite (H) bleaching technology is used in the third stage. The blea...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C9/147D21C9/14D21H21/32D21H17/64D21H17/66D21H17/22D21H23/08D21H23/14
Inventor 徐林杨明生母辉民王洪兵赵永健
Owner XINJIANG BOHU REED IND
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