CN1159842A - Treatment of chemical pulp with a chelating agent and an oxidizing agent in connection with bleaching - Google Patents
Treatment of chemical pulp with a chelating agent and an oxidizing agent in connection with bleaching Download PDFInfo
- Publication number
- CN1159842A CN1159842A CN 95195457 CN95195457A CN1159842A CN 1159842 A CN1159842 A CN 1159842A CN 95195457 CN95195457 CN 95195457 CN 95195457 A CN95195457 A CN 95195457A CN 1159842 A CN1159842 A CN 1159842A
- Authority
- CN
- China
- Prior art keywords
- paper pulp
- chelating agent
- bleaching
- pulp
- agent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1026—Other features in bleaching processes
- D21C9/1042—Use of chelating agents
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Detergent Compositions (AREA)
Abstract
A method of chlorine free bleaching of pulp where the metals in the pulp are removed by means of a chelating agent. The pulp is treated with the chelating agent at a pH 2-7 for a period of 5 minutes to 2 hours. The chelating agent is activated by the addition of an oxidizing agent. After the treatment the pulp is washed.
Description
The present invention relates to adopt not chloride bleached chemical medicament to come bleached chemical paper pulps.With a kind of chelating agent paper pulp is carried out the processing relevant with bleaching more precisely.
The no chlorine chemistry bleaching of paper pulp is carried out stage by stage with hydrogen peroxide mostly, generally also comprises with bleached chemical material oxygen, and be that ozone carries out sometimes.Use so-called peracid future probably, as peracetic acid and persulfuric acid.The paper pulp that obtains high ISO-brightness must be removed lignin from paper pulp, and lignin is a strong bonded.For the mode with gentleness, and use chemical agent to bleach economically, it is favourable being used in combination various bleached chemical medicaments.This is to be sequentially added into each chemical agent step by step, between each step paper pulp is cleaned.
Hydrogen peroxide is a kind of efficient bleached chemical medicament, if conditions of bleaching is appropriate, and only uses oxygen and hydrogen peroxide, can obtain the almost completely brightness of light on industrially scalable, i.e. almost 90% ISO brightness.Yet, this needs very special condition, for example need to paper pulp carry out boiling and with oxygen bleaching to very dark degree, promptly needing thereafter, (kappa) number is lower than 10, and before carrying out the hydrogen peroxide step, paper pulp should not be subjected to the interference of metal such as magnesium, copper, iron and other metals basically fully.The existence of these metals can make hydrogen peroxide decomposes, therefore do not have bleaching effect, and with the increase of tenor and the adding gradually of hydrogen peroxide, this influence can strengthen.When the hydrogen peroxide step proceeds to just the high-high brightness that can reach near chemical agent, it in addition very low tenor also very responsive.Obtain high-high brightness, carry out that content of magnesium must not surpass 1 gram/ton paper pulp in the paper pulp of hydrogen peroxide step.Yet in suitability for industrialized production, be difficult to reach this content.People need the paper pulp of high brightness, because such paper pulp price height.
Before the hydrogen peroxide step, with a kind of chelating agent such as EDTA or DTPA pulp treatment, clean paper pulp subsequently to remove metal ion, just can obtain the paper pulp of low-metal content.For example in EP-A-402335, reported this method, so-called Lignox method.Point out that in this report bleaching is handled and should be carried out at 3.1-9.0pH value, 10-100 ℃ (preferably 40-90 a ℃), reaches 6 hours.
The pulp industry of today is produced the paper making pulp of high brightness; its method is paper pulp to be carried out sufficient boiling handle and use oxygen bleaching; with be existing bleaching system and tower; the result needs the very long time of staying in chelating and blanching step; and between each blanching step, clean paper pulp very carefully; yet such cleaning need consume a large amount of water, so the bleaching system system must seal, to satisfy the various requirement of environmental protection.When setting up new equipment or original device transformed,, also require time of staying of each treatment step of paper pulp short as far as possible in order to reduce equipment volume and investment cost.It is important at last, also will reduce the addition of chelating agent,, and can't eliminate its may endanger at present environment because chelating agent is very expensive chemical agent.
The present invention is directed to the problems referred to above solution is provided.The present invention carried out a kind of more effective chelating agent and handles before the hydrogen peroxide step, so it more effectively is to make the chelating agent activation with oxidizer treatment paper pulp.Activation is meant the usefulness that increases chelating agent by oxidation, and the perhaps corresponding metal of removing from paper pulp carries out oxidation.In both cases, all be the chelating that has promoted metal, thereby reduce the content of metal in the paper pulp.According to method of the present invention, for example, the content of magnesium might be reduced to 1 gram/ton paper pulp.
Feature of the present invention is very clearly explained in the claims.
Now the present invention is described in detail with some following embodiments.
Paper pulp from previous processed step (as the step with the oxygen removal rod) cleans in wash engine earlier, adds acid or other solution adjustment pH value then.Mixing of acid or solution should be carried out equably, for example takes the way of paper pulp dilution or with a pump or blender.When using blender, guarantee very violent and uniform blending, in some cases, this is absolute important.The pH value should be adjusted to 2-7, preferably 4-6.
After the pH value is adjusted, in another blender, paper pulp is added chelating agent such as EDTA or DTPA and effectively mix.The suitable consumption of chelating agent is 1-5 kg/ton paper pulp, more preferably 1.5-2.5 kg/ton paper pulp.
In paper pulp, also to add oxidant.Can use oxygen or oxygen-containing gas such as air as oxidant.Also can use hydrogen peroxide or ozone.The amount of oxidant (comprising oxygen) generally should be 1-10 kg/ton paper pulp by pure oxygen, is preferably 3-7 kg/ton paper pulp.When adding hydrogen peroxide, its amount is preferably 1-2 kg/ton paper pulp for 0.5-3 kg/ton paper pulp.When using ozone, should add its amount of ozone/AIR MIXTURES, be preferably 1-2 kg/ton paper pulp for 0.5-3 kg/ton paper pulp.
Pulp pump is delivered in the reactor then, temperature of reactor is 40-130 ℃, is preferably 100-130 ℃, and wherein pressure remains the 1-10 crust, is preferably the 1.5-10 crust, is preferably the 3-8 crust.The time of staying of paper pulp in reactor is 5 minutes-2 hours, is preferably 10-60 minute.
To be input to from reactor the wash engine (temperature remains on more than 80 ℃) through the paper pulp that chelating agent is handled again, the metal ion of the agent combination that is chelated will be washed off effectively.
Used wash engine can be a pressure filter or be preferably a bench roller press that the latter is very effective, and low (the 4-5 rice of water consumption
3Water/ton paper pulp).
In chelating agent of the present invention was handled, the purpose of oxidizer was to make the chelating agent activation, and chelating agent can more effectively be combined with the metal ion that is harmful to such as the ion of magnesium, copper and iron.Oxidant also makes easier the separating out of metal ion and separates from paper pulp.Combine to such an extent that good metal is removed from paper pulp at cleaning step subsequently with chelating agent.So, from metallic angle, paper pulp is just much pure.
Paper pulp promptly leads to the back after cleaning bleaching process carries out chlorine-free bleaching with the bleaching agent that contains hydrogen peroxide.Because tenor is lower in the paper pulp, just might more effectively bleach, obtain maximum brightness.
Embodiment
Kappa is several 12.9, and brightness is the pine and cypress material wood pulp through oxygen bleaching of 40.0%ISO, select for use a kind of chelating agent handle (Q), again through cleaning, use hydrogen peroxide bleaching (P) at last.
The paper pulp of 10% concentration is carried out Q step 1 hour, and the final pH value is 5.0-5.2.Adding oxygen (Q2) and do not adding under the situation of oxygen (Q2) and carry out the Q step respectively.Clean paper pulp subsequently, the P step bleaching of under the situation of adding oxygen, pressurizeing again, this pressurization P step of adding oxygen is referred to as the PO step.Condition in the PO step is the paper pulp of 12% concentration, and temperature is 100-120 ℃, 2 hours time of staying, final pH value 10.0-10.4.The results are shown in following table.
| The Q step | The PO step | Brightness after the PO step | |
| Temperature ℃ | Add Q 2 | Kg peroxygen hydrogen/ton paper pulp | ????％ISO |
| ????100 | Do not have | ????40 | ????83.3 |
| ????100 | Have | ????40 | ????83.9 |
| ????110 | Do not have | ????20 | ????78.4 |
| ????110 | Have | ????20 | ????80.7 |
| ????110 | Do not have | ????40 | ????83.5 |
| ????110 | Have | ????40 | ????85.5 |
These results show, under identical hydrogen peroxide bleaching condition, activate chelation step by adding oxygen, can increase the last brightness of paper pulp.
Certainly the present invention is not subjected to the restriction of these embodiments, but can revise in scope of invention.
Claims (6)
1. remove the method that metal pair paper pulp in the paper pulp carries out chlorine-free bleaching with chelating agent for one kind, it is characterized in that paper pulp handled 5 minutes-2 hours with chelating agent under the pH2-7 condition, and add oxidant chelating agent is activated, after this clean paper pulp.
2. the method for claim 1 is characterized in that used oxidant is a kind of oxygen-containing gas, and its consumption is calculated as 1-10 kg/ton paper pulp by purity oxygen.
3. the method for claim 1 is characterized in that used oxidant is a hydrogen peroxide, and its consumption is a 0.5-3 kg/ton paper pulp.
4. the method for claim 1 is characterized in that used oxidant is an ozone, and its consumption is a 0.5-3 kg/ton paper pulp.
5. as the described method of arbitrary claim among the claim 1-4, it is characterized in that being is the 1.5-10 crust at pressure, temperature is to handle under 100-130 ℃ the condition.
6. as the described method of arbitrary claim among the claim 1-5, it is characterized in that cleaning being higher than under 80 ℃ the condition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9403396A SE504826C2 (en) | 1994-10-07 | 1994-10-07 | Treatment of chemical pulp with complexing agents in the presence of an oxidizing agent |
| SE9403396-6 | 1994-10-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1159842A true CN1159842A (en) | 1997-09-17 |
Family
ID=20395512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95195457 Pending CN1159842A (en) | 1994-10-07 | 1995-10-05 | Treatment of chemical pulp with a chelating agent and an oxidizing agent in connection with bleaching |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0784720A1 (en) |
| JP (1) | JPH10506965A (en) |
| CN (1) | CN1159842A (en) |
| AU (1) | AU686024B2 (en) |
| BR (1) | BR9509253A (en) |
| CA (1) | CA2199257A1 (en) |
| FI (1) | FI971401A (en) |
| NO (1) | NO971536D0 (en) |
| SE (1) | SE504826C2 (en) |
| WO (1) | WO1996011298A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1010617A3 (en) * | 1996-09-11 | 1998-11-03 | Solvay Interox | Paper pulp bleaching method |
| BR9711743A (en) * | 1996-09-11 | 1999-08-24 | Solvay Interox | Process of delignification and bleaching of chemical pulp |
| BE1010678A3 (en) * | 1996-10-11 | 1998-11-03 | Solvay Interox | Method for the delignification and bleaching of a chemical paper pulp |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE420430B (en) * | 1978-02-17 | 1981-10-05 | Mo Och Domsjoe Ab | PROCEDURE FOR WHEATING AND EXTRACTION OF LIGNOCELLULOSALLY MATERIALS WITH PEROXID CONTAINING BLACKS |
| EP0402335B2 (en) * | 1989-06-06 | 2001-03-14 | Eka Chemicals AB | Process for bleaching lignocellulose-containing pulps |
-
1994
- 1994-10-07 SE SE9403396A patent/SE504826C2/en not_active IP Right Cessation
-
1995
- 1995-10-05 WO PCT/SE1995/001135 patent/WO1996011298A1/en not_active Application Discontinuation
- 1995-10-05 CA CA 2199257 patent/CA2199257A1/en not_active Abandoned
- 1995-10-05 AU AU37124/95A patent/AU686024B2/en not_active Ceased
- 1995-10-05 EP EP95934912A patent/EP0784720A1/en not_active Withdrawn
- 1995-10-05 CN CN 95195457 patent/CN1159842A/en active Pending
- 1995-10-05 JP JP8512520A patent/JPH10506965A/en active Pending
- 1995-10-05 BR BR9509253A patent/BR9509253A/en not_active Application Discontinuation
-
1997
- 1997-04-04 FI FI971401A patent/FI971401A/en unknown
- 1997-04-04 NO NO971536A patent/NO971536D0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| NO971536L (en) | 1997-04-04 |
| FI971401A0 (en) | 1997-04-04 |
| NO971536D0 (en) | 1997-04-04 |
| SE9403396L (en) | 1996-04-08 |
| BR9509253A (en) | 1997-10-21 |
| SE504826C2 (en) | 1997-05-12 |
| JPH10506965A (en) | 1998-07-07 |
| EP0784720A1 (en) | 1997-07-23 |
| CA2199257A1 (en) | 1996-04-18 |
| AU3712495A (en) | 1996-05-02 |
| WO1996011298A1 (en) | 1996-04-18 |
| AU686024B2 (en) | 1998-01-29 |
| FI971401A (en) | 1997-04-04 |
| SE9403396D0 (en) | 1994-10-07 |
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| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C01 | Deemed withdrawal of patent application (patent law 1993) |