Method for removing metal ions of paper pulp and bleaching

A metal ion and pulp technology, applied in pulp bleaching, cellulose pulp post-treatment, papermaking, etc., to achieve the effects of reduced Fe content, moderate price, and reduced toxicity of long-term cumulative effects

Inactive Publication Date: 2009-11-11
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The metal ion removal process forms a new pollution-free bleaching process with peracetic acid and hydrogen peroxide, and no related technical reports have been seen so far

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] In pulp with a concentration of 5% by weight, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 The total dosage is 0.3%, the dosage of EDTA is 0.2%, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 The weight ratio of the amount used is 8:1. When pulp bleaching is performed to remove metal ions, the temperature of the treatment is controlled at 60° C. for 1.0 h. When the pulp is pretreated to remove metal ions, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 Mix for 0.5h, then add EDTA directly to continue the reaction until the specified time. Then carry out follow-up non-polluting bleaching treatment, in the peracetic acid bleaching section, the peracetic acid consumption is 1.5%, the DTPA consumption is 0.10%, the pulp concentration is 10% during processing, the temperature is 60 ° C, and the time is 1.5 hours; in the hydrogen peroxide bleaching section, hydrogen The amount of sodium oxide is 2.0%, the amount of sodium silicate is 1.5%, the amount of hydrogen peroxide is 1.0%, the amount of magne...

Embodiment 2

[0019] In pulp with a concentration of 5% by weight, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 The total dosage is 0.2%, the dosage of EDTA is 0.1%, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 The weight ratio of the amount used is 7:1. When pulp bleaching is performed to remove metal ions, the temperature of the treatment is controlled at 55°C and the time is 0.75h. When the pulp is pretreated to remove metal ions, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 Mix for 0.5h, then add EDTA directly to continue the reaction until the specified time. Then carry out follow-up pollution-free bleaching treatment, in the peracetic acid bleaching section, the peracetic acid consumption is 1.4%, the DTPA consumption is 0.10%, the pulp concentration is 10% during processing, the temperature is 55 ° C, and the time is 1.4 hours; in the hydrogen peroxide bleaching section, hydrogen The amount of sodium oxide is 1.8%, the amount of sodium silicate is 1.4%, the amount of hydrogen peroxide is 0.9%, the amou...

Embodiment 3

[0021] In pulp with a concentration of 5% by weight, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 The total dosage is 0.4%, the dosage of EDTA is 0.3%, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 The weight ratio of the amount used is 9:1. When pulp bleaching is performed to remove metal ions, the temperature of the treatment is controlled at 65° C. for 1.25 hours. When the pulp is pretreated to remove metal ions, Mg(CH 3 COO) 2 with Ca(CH 3 COO) 2 Mix for 0.5h, then add EDTA directly to continue the reaction until the specified time. Then carry out follow-up pollution-free bleaching treatment, in the peracetic acid bleaching section, the peracetic acid consumption is 1.6%, the DTPA consumption is 0.12%, the pulp concentration is 10% during processing, the temperature is 65 ° C, and the time is 1.6 hours; in the hydrogen peroxide bleaching section, hydrogen The consumption of sodium oxide is 2.2%, the consumption of sodium silicate is 1.6%, the consumption of hydrogen peroxide is 1.1%...

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PUM

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Abstract

The invention relates to a method for removing metal ions of paper pulp and bleaching and relates to a technique for removing metal ions of paper pulp and applications thereof in bleaching, belonging to the technical field of paper making. The method comprises the following steps of: (1) carrying out pretreatment for removing metal ions of the paper pulp, namely under the existence of Mg(CH(3)COO)2, Ca(CH(3)COO)2 and EDTA (disodium ethylene diamine tetraacetate), carrying out bleaching pretreatment to deoxidizing sulfate pulp; and (2) carrying out following no-pollution bleaching, carrying out following secondary bleaching treatment consisting of a peroxyacetic acid bleaching stage and a hydrogen peroxide bleaching stage on the paper pulp after the pretreatment for removing metal ions. The invention is simple and easy to operate and has obvious effect; the removal rate of the metal ions is high, and the removal rate of Mn is 80.5 percent. Compared with the conventional EDTA chelation treatment, the strength performance of the paper pulp can be improved; the Mg(CH3COO)2 and the Ca(CH3COO)2 can replace 60 percent of EDTA, consequently, the accumulative effect toxicity of the conventional chelating agent can be obviously reduced.

Description

technical field [0001] The invention relates to an oxygen-containing pulp bleaching process without pollution, in particular to a pulp metal ion removal process and its application in bleaching, and belongs to the technical field of papermaking. Background technique [0002] Due to the serious pollution of pulp chlorine bleaching and the high toxicity of wastewater, the pollution-free oxygen bleaching has been paid more and more attention and research. [0003] Hydrogen peroxide, peroxyacid, ozone, etc. are often used as bleaching agents in the oxygen bleaching process. When bleaching pulp with oxygen-containing bleaching agent, the metal ions in the pulp seriously affect the bleaching effect. Metal ions make the oxygen-containing bleaching agent decompose effectively, and the free radicals generated in it will have a negative impact on the quality of bleached pulp. Therefore, it is often necessary to use chelating agents such as EDTA and DTPA for chelating treatment before...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/00D21C9/16
Inventor 周学飞沈云霞卢秀娟
Owner KUNMING UNIV OF SCI & TECH
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