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Hydrogen peroxide bleaching method of waste paper deinking pulp using magnesium-based alkali

A waste paper deinking pulp and hydrogen peroxide technology, which is applied in pulp bleaching, secondary cellulose fiber, etc., can solve the problems of paper machine operation and paper quality, increasing wastewater pollution load, and restricting whiteness value-added. , to achieve the effect of reducing the production of scaling factor oxalate, low cost, and good whiteness stability

Inactive Publication Date: 2016-07-06
GUANGDONG IND TECHN COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the strong alkalinity of sodium hydroxide, hemicellulose and lignin will be dissolved, reducing the pulp yield and increasing the BOD of wastewater 5 and CODcr pollution load; at the same time, sodium hydroxide will make the initial alkalinity of the pulp system higher, and the resulting dissolved and colloidal substances (DCS) will have a negative impact on the operation of the paper machine and the quality of the paper; moreover, in the peroxidation A large amount of oxalate will be formed on the hydrogen bleaching production line, which is easily combined with calcium ions in the system to cause scaling problems such as calcium oxalate, which has become a major problem in production operations
In addition, the excessive alkaline environment will also cause the pulp to darken, restricting the increase in brightness

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A method for bleaching waste paper deinked pulp hydrogen peroxide using magnesium alkali, comprising the following steps:

[0021] 1), the waste paper deinking pulp is prepared into a waste paper deinking pulp solution to be bleached with a concentration of 10% by mass;

[0022] 2), in the waste paper deinking pulp solution to be bleached, add the sodium silicate that mass percent content is 1.00% of waste paper deinking pulp dry content, 0.25% ethylenediaminetetraacetic acid (EDTA), 1.45% hydrogen Magnesium oxide, 2.00% hydrogen peroxide, and stirred evenly, while controlling the bleaching temperature to be 70° C., and the reaction time to be 150 minutes.

[0023] 3) After bleaching, it enters the next process of papermaking.

[0024] Control experiment: as described in Example 1, the difference is that what is added in the bleaching process is 1.45% sodium hydroxide, and other conditions are all the same, and the brightness of gained bleached pulp is 53.1%ISO;

[00...

Embodiment 2

[0027] A method for bleaching waste paper deinked pulp hydrogen peroxide using magnesium alkali, comprising the following steps:

[0028] 1), the waste paper deinking pulp is prepared into a waste paper deinking pulp solution to be bleached with a concentration of 12% by mass;

[0029] 2), in the waste paper deinking pulp solution to be bleached, add the sodium silicate that mass percentage content is 3.00% of waste paper deinking pulp dry content, 0.25% ethylenediaminetetraacetic acid (EDTA), 0.50% di Ethylenetriaminepentaacetic acid (DTPA), 0.90% sodium hydroxide, 2.10% magnesium hydroxide, 4.00% hydrogen peroxide, and stir evenly, while controlling the bleaching temperature to 70°C, and the reaction time is 150min.

[0030] 3) After bleaching, it enters the next process of papermaking.

[0031] Control experiment: as described in Example 2, the difference is that the addition of 3.00% sodium hydroxide in the bleaching process, other conditions are the same, the brightness ...

Embodiment 3

[0034] A method for bleaching waste paper deinked pulp hydrogen peroxide using magnesium alkali, comprising the following steps:

[0035] 1), the waste paper deinking pulp is prepared into a waste paper deinking pulp solution to be bleached with a concentration of 10% by mass;

[0036] 2), in the waste paper deinking pulp solution to be bleached, add the sodium silicate that mass percent content is 2.00% of waste paper deinking pulp dry content, 0.50% ethylenediaminetetraacetic acid, 1.00% sodium hydroxide, 0.72% magnesium hydroxide, 3.00% hydrogen peroxide, and stir evenly, while controlling the bleaching temperature to be 80° C., and the reaction time is 120 minutes.

[0037] 3) After bleaching, it enters the next process of papermaking.

[0038] Control experiment: as described in Example 3, the difference is that it is 1.72% sodium hydroxide added in the bleaching process, and other conditions are all the same, and the brightness of gained bleached pulp is 56.1%ISO;

[0...

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Abstract

The invention discloses a hydrogen peroxide bleaching method of a waste paper deinking pulp using a magnesium-based alkali. The method includes the steps of: after the waste paper deinking pulp is diluted, adding 1.00% to 3.00% of sodium silicate, 0.25% to 0.75% of a chelating agent, 1.00% to 3.00% of alkali, and 2.00% to 4.00% of hydrogen peroxide in the mass percentage based on the waste paper deinking pulp absolute dry content, stirring mixture evenly and controlling the bleaching temperature between 70 DEG C to 90 DEG C, and controlling the reaction time between 90 min to 150min, wherein the alkali is a mixture of magnesium hydroxide or magnesium hydroxide and sodium hydroxide, and the mass percentage of the magnesium hydroxide in the mixture is in a range of 30% to 100%. Compared with a traditional technique which only uses the sodium hydroxide as an alkali liquid, the hydrogen peroxide bleaching method of the waste paper deinking pulp using the magnesium-based alkali is low in cost. A whiteness increment of a bleaching pulp reaches 3% ISO. A tensile index value increment reaches 5N*m / g. The hydrogen peroxide consumption decreases by 12%. The CODcr load in the bleaching pulp decreases by 24%. A fouling factor oxalate content decreases by 26%.

Description

technical field [0001] The invention belongs to the technical field of pulping and papermaking technology, in particular to a method for bleaching waste paper deinked pulp with hydrogen peroxide using magnesium alkali. Background technique [0002] The shortage of plant fiber raw materials for papermaking and environmental pollution have always been the main obstacles restricting the sustainable and healthy development of my country's pulp and paper industry. In recent years, waste paper pulping and papermaking technology has gradually attracted attention due to its advantages such as low raw material cost and environmental pollution load, and has developed rapidly. The recycling of waste paper is an effective way to solve the shortage of resources, energy waste and serious pollution faced by the paper industry. The recycled pulp after waste paper is shredded, because the whiteness of the paper is reduced in the process of shredding and deinking, so the bleaching technology...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/16D21H11/14
Inventor 云娜
Owner GUANGDONG IND TECHN COLLEGE