WO2016159403A1

WO2016159403A1 - Pulp-bleaching method using chelate compound

Info

Publication number: WO2016159403A1
Application number: PCT/KR2015/003127
Authority: WO
Inventors: 신수정; 박종문; 이재성; 송우용; 고영찬
Original assignee: 주식회사 아시아모빌; 충북대학교 산학협력단
Priority date: 2015-03-30
Filing date: 2015-03-30
Publication date: 2016-10-06

Abstract

Provided is a pulp-bleaching method which can simultaneously bleach pulp using chlorine dioxide (ClO₂) and remove transition metals using a chelate compound. According to the present invention, as the chlorine dioxide (ClO₂) bleaching and the removing of transition metals are simultaneously carried out as a single process during a bleaching process, the process is simplified compared to conventional pulp bleaching processes, whereby the present invention has the effects of increasing economy and improving bleaching efficiency.

Description

Pulp Bleaching Method Using Chelate Compound

The present invention relates to a pulp bleaching method, and more particularly, to a pulp bleaching method capable of simultaneously performing bleaching with chlorine dioxide (ClO ₂ ) and transition metal removal using a chelate compound. It is about.

In order to increase the whiteness of the pulp, a bleaching process is required after removing the material having a color structure including lignin after pulping. The bleaching process uses chlorine-based compounds, oxygen, hydrogen peroxide, and ozone. However, there is a limit to the use of a large amount of chemicals for high whiteness, such as the cost of chemicals used in the bleaching process and the waste water treatment caused by chemicals. have. Recent bleaching methods can be divided into a total chlorine free (TCF) process that does not use any form of chlorine and an element chlorine free (ECF) process that does not generate or use hypochlorite (HClO) and chlorine, which are particularly harmful to humans. Can be. The ECF bleaching method D ₀ -ED ₁ -ED ₂ is usually used for this purpose, where D ₀ , D ₁ and D ₂ represent the first, second and third steps using chlorine dioxide as the bleaching and delignining agent and E is Alkali extraction is indicated and each hyphen represents washing of the pulp, for example by addition of water and filtration of the resulting suspension.

On the other hand, conventionally, the process for removing the bleaching process and the transition metal is carried out in a separate process to increase the cost and the complicated process, and the chelate compound in the bleaching process using chlorine dioxide (ClO ₂ ) There is no prior document that discloses a technique for treating bleaching and transition metal removal in one process by input.

Accordingly, an object of the present invention is to (1) decomposing lignin contained in pulp using chlorine dioxide (ClO ₂ ), and (2) extracting lignin decomposed in step (1). (3) removing the transition metal at the same time as the primary bleaching by using chlorine dioxide (ClO ₂ ) and chelate compounds in the pulp from which lignin is removed by step (2); To provide a pulp bleaching method comprising the step of bleaching the secondary pulp (H ₂ O ₂ ) to the pulp from which the primary bleaching and transition metals are removed by the step (3). The purpose.

In addition, the present invention is used to remove the bleaching and transition metal in one process by using chlorine dioxide (ClO ₂ ) and chelate (chelate) compound in bleaching the pulp (pulp) prepared using the sugarcane bags (seed) Another object is to provide an optimized bleaching method that can be achieved.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned above can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The present invention to achieve the above object is (1) using chlorine dioxide (ClO ₂ ) to decompose lignin (lignin) contained in the pulp, and (2) the lignin (lignin) decomposed in step (1) Extraction and (3) removal of transition metals simultaneously with primary bleaching using chlorine dioxide (ClO ₂ ) and chelate compounds in pulp from which lignin has been removed by step (2). Step and (4) characterized in that it comprises a second step of bleaching using a water peroxide (H ₂ O ₂ ) in the pulp from which the primary bleaching and transition metal is removed by the step (3).

The pulp that is the target of bleaching is irrelevant to any woody or non-woody one and is very effective in bleaching pulp produced using sugarcane bagssse treated as waste.

In step (1), chlorine dioxide (ClO ₂ ) may be mixed with the dried pulp (pulp) in a weight ratio of 3 to 6: 5 to 25 to decompose lignin, preferably chlorine dioxide (ClO _2). ): The dried pulp (pulp) = 3 to 6: It is mixed at a weight ratio of 5 to 15. In addition, the reaction temperature may be maintained at 50 to 90 ℃ but preferably maintained at 70 to 80 ℃, pH conditions can be maintained at 3.0 to 5.0 and preferably reacted at pH 3.5 to 4.0 conditions. On the other hand, the reaction time may be 30 to 120 minutes, it is preferred to react for 55 to 65 minutes.

The (2) lignin in step (lignin) extraction procedure (1) The chlorine dioxide used in step (ClO _2), but to use 0.25 to chlorine dioxide in 1-fold (ClO ₂₎ of the weight, preferably (1) It is to use chlorine dioxide (ClO ₂ ) of 0.4 to 0.6 times the weight used in the step. On the other hand, the reaction temperature may be maintained at 50 to 90 ℃ but preferably maintained at 70 to 80 ℃, the reaction time may be 30 to 120 minutes, it is preferred to react for 55 to 65 minutes.

In step (3), the lignin is extracted by the step (2), and then 0.3 to 1.0% of chlorine dioxide (ClO ₂ ) and lignin are extracted based on the total weight of the total pulp. 0.1 to 0.5% of chelate compound by mass, and preferably lignin is extracted, and 0.4 to 0.6% of chlorine dioxide (ClO ₂ ) and lignin by weight of dry pulp. ) And then 0.3 to 0.4% of the chelate compound (chelate) relative to the total weight of the pulp. On the other hand, the reaction temperature may be maintained at 50 to 90 ℃ but preferably maintained at 70 to 80 ℃, pH conditions can be maintained at 3.0 to 5.0 and preferably reacting at pH 4.0 to 4.5 conditions, the reaction time Although it may be 30 to 120 minutes, it is preferable to react for 55 to 65 minutes. In this process, chlorine dioxide (ClO ₂ ) bleaching and transition metal removal can be carried out simultaneously in one process, thereby increasing the bleaching efficiency and simplifying the bleaching step compared to the conventional ECF bleaching DEDED bleaching step sequence. There is an advantage.

The (4) The chlorine dioxide used in the step (3) in step (ClO _2), but to use 0.25 to 1 chlorine dioxide (ClO ₂₎ of times the weight, preferably dioxide used in step (1) Chlorine dioxide (ClO ₂ ) of 0.4 to 0.6 times the weight of chlorine (ClO ₂ ) is used, and hydrogen peroxide (H ₂ O ₂ ) added simultaneously with the chlorine dioxide (ClO ₂ ) is determined by step (3). 0.5 to 1.5% of the total pulp mass removed from the primary bleaching and transition metal may be used, and preferably 0.8 to 1.0%. Meanwhile, the reaction temperature may be maintained at 50 to 90 ° C., but preferably at 70 to 80 ° C., and the reaction time may be 30 to 120 minutes, but preferably 55 to 65 minutes.

In the present invention as described above, by simultaneously treating the chlorine dioxide (ClO ₂ ) bleaching and the transition metal removal process of the bleaching process as one process, the process is simplified compared to the conventional pulp bleaching process to improve the economic efficiency as well as improve the bleaching efficiency It can be effective. In addition, by treating the conventional two-step process as a single process there is an effect that can significantly reduce the washing waste water generated in the intermediate process.

1 is a process chart of the bleaching method according to the present invention.

2 is a graph showing the whiteness and residual hydrogen peroxide concentration of the pulp prepared by the present invention.

3 is a graph showing the residual hydrogen peroxide concentration of the pulp prepared by the present invention.

Figure 4 is a graph showing the whiteness and residual hydrogen peroxide concentration of the pulp prepared by the present invention.

The above objects, features, and advantages will become more apparent from the following detailed description with reference to the accompanying drawings, and as a result, those skilled in the art may easily implement the technical idea of the present invention. You can do it. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

On the other hand, in the following the pre-drying pulp refers to pulp with a water content of 0%, D is bleaching using chlorine dioxide (ClO ₂ ), E is an alkali extraction process, Q is a transition metal removal using a chelate compound (chelate) Process, P means bleaching process using hydrogen peroxide (H ₂ O ₂ ).

실시예 1. 이산화염소(ClOExample 1 Chlorine Dioxide (ClO) ₂₂ )를 이용하여 펄프(pulp)에 포함된 리그닌(lignin) 분해Lignin breakdown in pulp using

Sugarcane bagasse pulp was prepared and bleached with chlorine dioxide (ClO ₂ ). The concentration of pulp was prepared at 10% and reacted with 5.0% chlorine dioxide (ClO ₂ ) (4% on oven dry pulp) relative to the mass of the dry pulp. The reaction temperature was reacted for 1 hour under 75 ℃ condition and the pH was adjusted to 3.0 using acetic acid. The acid used for the purpose of adjusting the pH may use other types of acid such as hydrochloric acid and sulfuric acid.

실시예 2. 리그닌(lignin) 추출 및 제거Example 2. Lignin Extraction and Removal

After completing the process according to Example 1, the washed chemical pulp was prepared at a concentration of 10% and reacted with 0.5 times sodium hydroxide (NaOH) of the amount of chlorine dioxide (ClO ₂ ) used in Example 1. The reaction temperature was reacted for 1 hour under 75 ° C., and after washing, the lignin was removed to prevent the oxidant from being used in the degraded lignin.

실시예 3. 1차 표백 및 전이금속 제거Example 3 Primary Bleaching and Transition Metal Removal

After completing the Example 2 process, the washed chemical pulp was prepared at a concentration of 10% and reacted with chlorine dioxide (ClO ₂ ) in a mass corresponding to 0.5% of the total weight of the dried pulp. At this time, a chelate compound having a mass corresponding to 0.3% of the total weight of the dried pulp was added to react with chlorine dioxide (ClO ₂ ) to remove the transition metal.

The chelate (chelate) compound was used DTPA (diethylene tetramine penta-acetic acid), the reaction temperature was reacted for 1 hour under 75 ℃ conditions, the pH was adjusted to 4.0 using acetic acid (acetic acid). The acid used for the purpose of adjusting the pH may use other types of acid such as hydrochloric acid and sulfuric acid.

On the other hand, the chelate (chelate) compounds may be used such as EDTA (ethylenediamine tetraacetic acid), NTA, CyDTA, DTPA, GEDTA, DHEG.

실시예 4. 2차 표백Example 4. Secondary Bleaching

After the Example 3 process, the washed chemical pulp was prepared at a concentration of 10%, and the reaction was performed by using sodium hydroxide (NaOH) of 0.5 times the amount of chlorine dioxide (ClO ₂ ) used in Example 3 relative to the mass of the dry pulp. I was. At this time, by adding the hydrogen peroxide (H ₂ O ₂ ) of the mass corresponding to 1.0% of the mass of the dry pulp from which the transition metal was removed by Example 3 was reacted to cause further bleaching. Reaction temperature was made to react for 1 hour on 75 degreeC conditions.

실시예 5. 실험결과Example 5 Experimental Results

As shown in Figs. 2 to 4, the whiteness of the bleached pulp carried out from Examples 1 to 4 was measured based on TAPPI 525. When looking at the bar graph, it can be seen that the amount of chlorine dioxide used is smaller than that of the typical DEDE process and the peroxide bleaching does not significantly affect the whiteness even though the process is reduced by one step. have. In the case of chelating compound treatment, it was confirmed that the chlorine dioxide treatment had a higher whiteness than the sample.

As mentioned above, specific portions of the present disclosure have been described in detail, and it is apparent to those skilled in the art that such specific techniques are merely preferred embodiments, and thus the scope of the present disclosure is not limited thereto. something to do. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims

In the bleaching method of pulp (pulp) manufactured using sugarcane bagasse,

(1) decomposing lignin contained in pulp using chlorine dioxide (ClO 2 ),

(2) extracting lignin degraded in step (1);

(3) removing transition metals simultaneously with primary bleaching using chlorine dioxide (ClO 2 ) and chelate compounds in pulp from which lignin has been removed by step (2);

(4) a pulp bleaching method comprising the step of bleaching the secondary bleaching using hydrogen peroxide (H 2 O 2 ) in the pulp from which the primary bleaching and transition metals are removed by step (3).
The method of claim 1,

In step (1), pulp and chlorine dioxide (ClO 2 ) are mixed at a weight ratio of 5 to 25: 3 to 6, and reacted at 50 to 90 ° C. and pH 3.0 to 7.0 to decompose lignin. Pulp bleaching method.
The method of claim 1,

Pulp bleaching method characterized in that the reaction at 50 to 90 ℃ using 0.25 to 1 times the alkali relative to the weight of chlorine dioxide (ClO 2 ) used in step (1) to (1).
The method of claim 1,

In step (3), using 0.3 to 1.0% of chlorine dioxide (ClO 2 ) and 0.1 to 0.5% of chelate compound to pulp mass, reacting at 50 to 90 ° C. and pH 3.0 to 7.0 to bleach and transfer Bleaching method characterized in that the metal removal at the same time.
The method of claim 1,

Hydrogen peroxide (H 2 O 2 ) corresponding to 0.5 to 1.5% by weight of alkali and pulp mass corresponding to the weight of 0.25 to 1 times the weight of chlorine dioxide (ClO 2 ) used in step (4) to (3) Bleaching method characterized in that the secondary bleaching at 50 to 90 ℃ using.
(1) decomposing lignin contained in pulp using chlorine dioxide (ClO 2 ),

(2) extracting lignin degraded in step (1);

(3) removing the transition metal at the same time as the first bleaching using chlorine dioxide (ClO 2 ) and a chelate compound in the pulp from which lignin is removed by step (2);

(4) a pulp bleaching method comprising the steps of bleaching the primary pulp and the transition metal from the pulp from which the primary metal is removed by using peroxide (H 2 O 2 ).
The method of claim 6,

Pulp bleaching method, characterized in that in the step (1) to mix the pulp and chlorine dioxide (ClO 2 ) in a weight ratio of 5 to 25: 3 to 6 to decompose lignin (lignin).
The method of claim 6,

The pulp bleaching method, characterized in that for reacting an alkali of 0.25 to 1 times the weight of the chlorine dioxide (ClO 2 ) used in step (2) to (1).
The method of claim 6,

Bleaching method characterized in that the bleaching and the removal of the transition metal at the same time using a 0.3 to 1.0% chlorine dioxide (ClO 2 ) and 0.1 to 0.5% chelate compound (chelate) relative to the pulp mass in step (3).
The method of claim 6,

It is characterized in that the second bleaching of hydrogen peroxide (H 2 O 2 ) of 0.25 to 1 times alkali and pulp mass of 0.25 to 1 times the weight of chlorine dioxide (ClO 2 ) used in step (4) to (3). Bleaching method.