EP0307295A1 - Process for producing a bleached paper pulp comprising a carbon dioxide treatment after bleaching - Google Patents

Process for producing a bleached paper pulp comprising a carbon dioxide treatment after bleaching Download PDF

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Publication number
EP0307295A1
EP0307295A1 EP88402223A EP88402223A EP0307295A1 EP 0307295 A1 EP0307295 A1 EP 0307295A1 EP 88402223 A EP88402223 A EP 88402223A EP 88402223 A EP88402223 A EP 88402223A EP 0307295 A1 EP0307295 A1 EP 0307295A1
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EP
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Prior art keywords
pulp
bleaching
whiteness
bleached
treatment
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EP88402223A
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German (de)
French (fr)
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EP0307295B1 (en
Inventor
Raymond Lachapelle
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Air Liquide Canada Inc
Canadian Liquid Air Ltd
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Air Liquide Canada Inc
Canadian Liquid Air Ltd
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Priority to AT88402223T priority Critical patent/ATE62287T1/en
Publication of EP0307295A1 publication Critical patent/EP0307295A1/en
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    • 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

Definitions

  • the present invention relates to a process for manufacturing paper pulp, the bleaching of which includes an H or P treatment phase before the pulp is purified or passed through the paper machine.
  • the bleaching sequences comprise one or more successive stages and generally separated by washes.
  • the stages are characterized by the bleaching agent used. Mention may be made, by way of reference and without limitation of examples of sequences: in the case of chemical pulps, and Kraft in particular, CEHH, CEP, CEDED, CEDP, CEHDP and, CEDED (P), and CEHD (P ); in the case of sulfite pastes, CEH, HH, H and OH; in the case of mechanical pulps, RP, PP, RPRP, PRP or P; in the case of semi-chemical pastes, RP, HH, OH.
  • the pulp is generally treated using SO2 which takes place before the pulp is refined and / or passed through the paper machine.
  • SO2 sulfur dioxide treatment
  • the purpose and effect of sulfur dioxide treatment is to: - destroy the residuals, or chemical residues of the bleaching stages, whether they are residues from treatment D (chlorine dioxide), treatment H (hypochlorite), or treatment P (peroxide); - eliminate the metal cations (Iron, Manganese or Copper) which reduce the whiteness and speed up the subsequent whiteness reversal process; - neutralize, even acidify, the pulp, because it is known that alkaline conditions have a harmful effect of blackening of the pulp and paper. This last aspect is therefore essential.
  • the present invention relates to a method for manufacturing paper pulp of the type in which the bleaching comprises an H or P phase before the bleached pulp passes through the purifier and / or the paper machine, characterized in that one treats the bleached pulp essentially with carbonic acid and directly after the bleaching treatment.
  • the method according to the invention can be implemented whether the pulp is mechanical, chemical or comes from recycling of inked paper, and whatever the bleaching sequence, with multiple or single stage, provided that the last or single stage is type H or P.
  • thermomechanical TMP
  • CTMP chemico-thermomechanical
  • the dough is usually washed and treated in the form of a suspension.
  • the carbonic acid is introduced into the washing waters of the last or only bleaching step. It can also be introduced into the suspension after it has left the last or only bleaching step.
  • the carbonic acid can be introduced in gaseous, liquid form, or in solution, for example in the washing or dilution water of the suspension, or in the suspension.
  • the pulp is treated in the usual way, that is to say that it can be stored or directly introduced into the paper machine, or be purified, for example.
  • carbon dioxide according to the invention in addition to the fact that it fulfills the purpose of neutralizing the dough, avoids harmful alkaline conditions and gives whiteness results. satisfactory and better than with SO2, (as will appear in the examples), has the following advantages: - acidification is simple to control and, CO2 being a weak acid, the risks of over-acidification are less than with SO2 ; - corrosion and water pollution due to the use of this acid are non-existent; - the development of microorganisms which occurs in the dough, during storage for example, and which blackens the dough, is avoided, since the residuals of steps P or H, not destroyed, behave like mild biocides; - The implementation of the injection is simple; - the bleaching treatment residues, not destroyed, are reusable.
  • thermomechanical pulp is treated in a PRP bleaching sequence.
  • a whiteness of 70.65% ISO is reached after the second treatment P which consisted in treating the dough using a solution containing: 2% H2O2 relative to the dough 1.5% NaOH 1.0% Na2 SiO3 0.05% MgSO4 while the concentration of the paste was 10%, the temperature 65 ° C and the retention time 2 h.
  • the final pH is 8.3 and the residual peroxide 1.3% compared to the dry paste.
  • the dough is brought to a concentration of 27% and is divided into two samples.
  • the SO au liquor is added to the 1st sample to adjust the pH to 5.5 and the concentration is reduced to 10%.
  • the residual peroxide is unchanged.
  • the whiteness is determined and equals 81.17% ISO.
  • thermomechanical pulp (whiteness 57.43% ISO) is bleached in step P, using a solution comprising 2% H2O2 2.0% NaOH 2.0% Na2SiO3 0.05% MgSO4 0.2% DTPA (diethylene trimine penta-sodium acetate)
  • the concentration of the paste is 10%, the temperature 85 ° C and the retention time 30 minutes.
  • the final pH is 8.1 and the residual peroxide is equivalent to 0.61% H2O2 compared to the dry paste.
  • the 10% bleached pulp is divided into two samples.
  • SO2 is added to the first sample, to adjust the pH to 5.4.
  • CO2 is injected into the paste of the second sample until a pH of 5.6 is obtained.
  • the residual peroxide is determined and reaches 0.58%.
  • the dough is drained and the whiteness is determined on formulas according to the standard procedure.
  • the whiteness is 74.24% ISO.
  • the residual peroxide can be extracted from the suspension and recovered for subsequent bleaching.
  • the whiteness after adjusting the pH by CO2 is greater than the whiteness after adjusting the pH by SO2.
  • a softwood-based chemical kraft pulp is bleached in a C D E O DP sequence.
  • step P the pH is 9.9 and the dough sample is divided into two parts.
  • the first sample is treated with SO2 to adjust the pH to 6.0.
  • the suspension is drained and the prepared formulas have a whiteness of 86.50% ISO. After one hour of aging at 105 ° C, the whiteness is 83.24% ISO.
  • the second pulp sample is treated with CO2 until the pH is adjusted to 6.3.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Materials For Medical Uses (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)

Abstract

Process for producing a paper pulp comprising a stage of H or P treatment just before the purification of the pulp or its transfer to the papermaking machine, where the neutralisation of the bleached pulp is performed with the aid of carbonic acid instead of sulphur dioxide.

Description

La présente invention concerne un procédé de fabrication de pâte à papier dont le blanchiment comporte une phase de traitement H ou P avant l'épuration de la pâte ou son passage dans la machine à papier.The present invention relates to a process for manufacturing paper pulp, the bleaching of which includes an H or P treatment phase before the pulp is purified or passed through the paper machine.

Dans l'industrie de la pâte à papier, que celle-ci soit de type chimique, mécanique ou même provienne du retraitement de papier désencré, on procède à une séquence de blanchiment de la pâte avant d'en faire du papier.In the pulp industry, whether it is chemical, mechanical or even comes from the reprocessing of de-inked paper, a pulp bleaching sequence is carried out before making it into paper.

Les séquences de blanchiment comportent une ou plusieurs étapes successives et en général séparées par des lavages. Les étapes sont caractérisées par l'agent blanchissant utilisé. On peut citer, à titre de référence et de façon non limitative des exemples de séquences : dans le cas de pâtes chimiques, et Kraft en particulier, CEHH, CEP, CEDED, CEDP, CEHDP et, CEDED(P), et CEHD(P) ; dans le cas des pâtes au sulfite, CEH, HH, H et OH ; dans le cas de pâtes mécaniques, RP, PP, RPRP, PRP ou P ; dans le cas de pâtes semi-chimiques, RP, HH, OH.The bleaching sequences comprise one or more successive stages and generally separated by washes. The stages are characterized by the bleaching agent used. Mention may be made, by way of reference and without limitation of examples of sequences: in the case of chemical pulps, and Kraft in particular, CEHH, CEP, CEDED, CEDP, CEHDP and, CEDED (P), and CEHD (P ); in the case of sulfite pastes, CEH, HH, H and OH; in the case of mechanical pulps, RP, PP, RPRP, PRP or P; in the case of semi-chemical pastes, RP, HH, OH.

Les publications suivantes peuvent être utilisées à titre d'exemples de mise en oeuvre de procédé de blanchiment : US 3,806,404, EP 187.477.The following publications can be used as examples of implementation of the bleaching process: US 3,806,404, EP 187,477.

A la fin du blanchiment, on procède en général à un traitement de la pâte à l'aide de SO₂ qui intervient avant le raffinage de la pâte et/ou son passage dans la machine à papier. Le traitement au dioxyde de soufre, en général en solution, a pour but et pour effet de :
- détruire les résiduels, ou résidus chimiques des étapes de blanchiment, que ce soient des résidus de traitement D (dioxyde de chlore), de traitement H (hypochlorite), ou de traitement P (peroxyde) ;
- éliminer les cations métalliques (Fer, Manganèse ou Cuivre) qui diminuent la blancheur et accélèrent le processus ultérieur de reversion de blancheur ;
- neutraliser, voire acidifier, la pâte, car il est connu que des conditions alcalines ont un effet néfaste de noircissement de la pâte et du papier. Ce dernier aspect est donc essentiel.At the end of the bleaching, the pulp is generally treated using SO₂ which takes place before the pulp is refined and / or passed through the paper machine. The purpose and effect of sulfur dioxide treatment, generally in solution, is to:
- destroy the residuals, or chemical residues of the bleaching stages, whether they are residues from treatment D (chlorine dioxide), treatment H (hypochlorite), or treatment P (peroxide);
- eliminate the metal cations (Iron, Manganese or Copper) which reduce the whiteness and speed up the subsequent whiteness reversal process;
- neutralize, even acidify, the pulp, because it is known that alkaline conditions have a harmful effect of blackening of the pulp and paper. This last aspect is therefore essential.

Cet "effet SO₂" multiple est connu sous le nom de "souring".This multiple "SO₂ effect" is known as "souring".

La destruction des résiduels est nécessaire dans le cas de traitement D (ClO₂), car le CLO₂ est corrosif et toxique et sa présence incompatible avec la suite du traitement (corrosion des laveurs).The destruction of the residuals is necessary in the case of treatment D (ClO₂), because the CLO₂ is corrosive and toxic and its presence incompatible with the continuation of the treatment (corrosion of the scrubbers).

Cependant, dans le cas de traitement H ou P, au contraire, les résidus ne sont pas nuisibles, comme l'a mis en évidence la demanderesse. Leur présence a des effets favorables car ils continuent à agir comme agent blanchissant et ont de plus une action de biocide doux.However, in the case of H or P treatment, on the contrary, the residues are not harmful, as the applicant has demonstrated. Their presence has favorable effects because they continue to act as a whitening agent and moreover have a mild biocidal action.

La demanderesse a donc mis en évidence dans le cas de traitement blanchissant mettant en oeuvre unt étape finale H ou P ou une étape unique H ou P, que l'utilisation de SO₂ n'est pas nécessaire, et que l'on peut neutraliser la pâte avec de l'acide carbonique, CO₂, utilisé à la place de SO₂.The Applicant has therefore demonstrated in the case of a whitening treatment using a final step H or P or a single step H or P, that the use of SO₂ is not necessary, and that it is possible to neutralize the paste with carbonic acid, CO₂ , used in place of SO₂.

Ainsi la présente invention concerne un procédé de fabrication de pâte à papier du type où le blanchiment comporte une phase H ou P avant le passage de la pâte blanchie dans l'épurateur et/ou la machine à papier, caractérisé en ce que l'on traite la pâte blanchie essentiellement à l'aide d'acide carbonique et directement après le traitement de blanchiment.Thus, the present invention relates to a method for manufacturing paper pulp of the type in which the bleaching comprises an H or P phase before the bleached pulp passes through the purifier and / or the paper machine, characterized in that one treats the bleached pulp essentially with carbonic acid and directly after the bleaching treatment.

Le procédé selon l'invention peut être mis en oeuvre que la pâte soit mécanique, chimique ou provienne de recyclage de papier encré, et quel que soit la séquence de blanchiment, à étape multiple ou unique, pourvu que la dernière ou unique étape soit de type H ou P.The method according to the invention can be implemented whether the pulp is mechanical, chemical or comes from recycling of inked paper, and whatever the bleaching sequence, with multiple or single stage, provided that the last or single stage is type H or P.

L'invention s'applique ainsi aux pâtes thermomécaniques (TMP) ou chimico-thermomécaniques (CTMP) qui ne subissent usuellement qu'un traitement de blanchiment.The invention thus applies to thermomechanical (TMP) or chemico-thermomechanical (CTMP) pastes which usually only undergo a bleaching treatment.

Après cette étape H ou P, la pâte est usuellement lavée et traitée sous forme d'une suspension.After this step H or P, the dough is usually washed and treated in the form of a suspension.

L'acide carbonique est selon l'invention introduit dans les eaux de lavage de la dernière ou unique étape de blanchiment. Il peut également être introduit dans la suspension à sa sortie de la dernière ou unique étape de blanchiment.According to the invention, the carbonic acid is introduced into the washing waters of the last or only bleaching step. It can also be introduced into the suspension after it has left the last or only bleaching step.

L'acide carbonique peut être introduit sous forme gazeuse, liquide, ou en solution, par exemple dans l'eau de lavage ou de dilution de la suspension, ou dans la suspension.The carbonic acid can be introduced in gaseous, liquid form, or in solution, for example in the washing or dilution water of the suspension, or in the suspension.

Après le traitement de neutralisation selon l'invention, la pâte est traitée de façon usuelle, c'est-à-dire qu'elle peut être stockée ou directement introduite dans la machine à papier, ou être épurée, par exemple.After the neutralization treatment according to the invention, the pulp is treated in the usual way, that is to say that it can be stored or directly introduced into the paper machine, or be purified, for example.

L'utilisation du dioxyde de carbone selon l'invention, outre le fait qu'elle remplit le but de neutralisation de la pâte, évite les conditions alcalines néfastes et donne des résultats de blancheur satisfaisants et meilleurs qu'avec SO₂,(comme cela apparaîtra dans les exemples), présente les avantage suivants :
- l'acidification est simple à contrôler et, le CO₂ étant un acide faible, les risques de suracidification sont moindres qu'avec le SO₂;
- la corrosion et la pollution des eaux dues à l'emploi de cet acide sont inexistantes ;
- le développement de microorganismes qui se produit dans la pâte, lors du stockage par exemple, et qui noircit la pâte, est évité, car les résiduels des étapes P ou H, non détruits, se comportent comme des biocides doux ;
- la mise en oeuvre de l'injection est simple ;
- les résiduels de traitement de blanchiment, non détruits, sont réutilisables.The use of carbon dioxide according to the invention, in addition to the fact that it fulfills the purpose of neutralizing the dough, avoids harmful alkaline conditions and gives whiteness results. satisfactory and better than with SO₂, (as will appear in the examples), has the following advantages:
- acidification is simple to control and, CO₂ being a weak acid, the risks of over-acidification are less than with SO₂ ;
- corrosion and water pollution due to the use of this acid are non-existent;
- the development of microorganisms which occurs in the dough, during storage for example, and which blackens the dough, is avoided, since the residuals of steps P or H, not destroyed, behave like mild biocides;
- The implementation of the injection is simple;
- the bleaching treatment residues, not destroyed, are reusable.

D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture des exemples ci-après, qui présentent diverses utilisations, non limitatives, de l'acide carbonique pour l'ajustement du pH de pâtes, et les résultats de blancheur qui en découlent.Other characteristics and advantages of the invention will appear on reading the examples below, which present various uses, without limitation, of carbonic acid for adjusting the pH of pasta, and the whiteness results which result therefrom. .

EXEMPLE 1 : EXAMPLE 1 :

On traite une pâte thermomécanique dans une séquence de blanchiment PRP. On atteint une blancheur de 70,65% ISO après le second traitement P qui a consisté à traiter la pâte à l'aide d'une solution contenant : 2 % H₂O₂ par rapport à la pâte
1,5 % NaOH
1,0 % Na₂ SiO₃
0,05 % MgSO₄
alors que la concentration de la pâte était de 10 %, la température 65°C et le temps de rétention 2 h.A thermomechanical pulp is treated in a PRP bleaching sequence. A whiteness of 70.65% ISO is reached after the second treatment P which consisted in treating the dough using a solution containing: 2% H₂O₂ relative to the dough
1.5% NaOH
1.0% Na₂ SiO₃
0.05% MgSO₄
while the concentration of the paste was 10%, the temperature 65 ° C and the retention time 2 h.

Le pH final est de 8,3 et le peroxyde résiduel de 1,3 % par rapport à la pâte sèche.The final pH is 8.3 and the residual peroxide 1.3% compared to the dry paste.

On amène la pâte à une concentration de 27 % et on la divise en deux échantillons.The dough is brought to a concentration of 27% and is divided into two samples.

1. On ajoute au 1er échantillon de la liqueur de SO₂ pour ajuster le pH à 5,5 et on ramène la concentration à 10 %.1. The SO au liquor is added to the 1st sample to adjust the pH to 5.5 and the concentration is reduced to 10%.

Il n'y a pas de peroxyde résiduel dans la pâte. Les formettes préparées avec cet échantillon ont une blancheur de 80,05 % ISO.There is no residual peroxide in the dough. The formulas prepared with this sample have a whiteness of 80.05% ISO.

2. On dissous du CO₂ dans de l'eau et la pâte du deuxième échantillonpour obtenir une suspension à 10 % de concentration et ajuster le pH à 5, 7.2. Dissolve CO₂ in water and the paste from the second sample to obtain a suspension at 10% concentration and adjust the pH to 5.7.

Le peroxyde résiduel est inchangé. La blancheur est déterminée et égale 81,17 % ISO.The residual peroxide is unchanged. The whiteness is determined and equals 81.17% ISO.

Par cet exemple, on montre que l'ajustement du pH par CO₂ après un traitement peroxydé améliore la blancheur par rapport à un ajustement du pH par SO₂.By this example, it is shown that adjusting the pH by CO₂ after a peroxidized treatment improves the whiteness compared to adjusting the pH by SO₂.

EXEMPLE 2EXAMPLE 2

Une pâte thermomécanique non blanchie (blancheur 57,43 %ISO) est blanchie en une étape P, à l'aide d'une solution comportant
2 % H₂O₂
2,0 % NaOH
2,0 % Na₂SiO₃
0,05 % MgSO₄
0,2 % DTPA (diethylène trimine penta-acétate de sodium)An unbleached thermomechanical pulp (whiteness 57.43% ISO) is bleached in step P, using a solution comprising
2% H₂O₂
2.0% NaOH
2.0% Na₂SiO₃
0.05% MgSO₄
0.2% DTPA (diethylene trimine penta-sodium acetate)

La concentration de la pâte est de 10 %, la température de 85°C et le temps de rétention de 30 minutes.The concentration of the paste is 10%, the temperature 85 ° C and the retention time 30 minutes.

Le pH final est de 8,1 et le peroxyde résiduel est équivalent à 0,61 % H₂O₂ par rapport à la pâte sèche.The final pH is 8.1 and the residual peroxide is equivalent to 0.61% H₂O₂ compared to the dry paste.

La pâte blanchie à 10 % est divisée en deux échantillons.The 10% bleached pulp is divided into two samples.

1. On ajoute SO₂ au premier échantillon, pour ajuster le pH à 5,4.1. SO₂ is added to the first sample, to adjust the pH to 5.4.

Il n'y a pas de peroxyde résiduel après l'injection de SO₂. La pâte est égouttée et les formettes de blancheur réalisées selon la procédure standard.There is no residual peroxide after the SO₂ injection. The dough is drained and the whiteness formulas produced according to the standard procedure.

la blancheur est de 72,14 % ISO.the whiteness is 72.14% ISO.

2. On injecte CO₂ dans la pâte du deuxième échantillon jusqu'à obtenir un pH de 5,6.2. CO₂ is injected into the paste of the second sample until a pH of 5.6 is obtained.

Le peroxyde résiduel est déterminé et atteint 0,58 %.The residual peroxide is determined and reaches 0.58%.

La pâte est égouttée et on détermine la blancheur sur des formettes selon la procédure standard. La blancheur est de 74,24 % ISO.The dough is drained and the whiteness is determined on formulas according to the standard procedure. The whiteness is 74.24% ISO.

Par cet exemple, on montre d'une part que le peroxyde résiduel peut être extrait de la suspension et récupéré en vue d'un blanchiment ultérieur.By this example, it is shown on the one hand that the residual peroxide can be extracted from the suspension and recovered for subsequent bleaching.

D'autre part,la blancheur après ajustement du pH par CO₂ est supérieure à la blancheur après ajustement du pH par SO₂.On the other hand, the whiteness after adjusting the pH by CO₂ is greater than the whiteness after adjusting the pH by SO₂.

EXEMPLE 3EXAMPLE 3

Une pâte kraft chimique à base de résineux est blanchie dans une séquence CDEODP.A softwood-based chemical kraft pulp is bleached in a C D E O DP sequence.

Après l'étape P, le pH est de 9,9 et on divise l'échantillon de pâte en deux parties.After step P, the pH is 9.9 and the dough sample is divided into two parts.

1. Le premier échantillon est traité au SO₂ pour ajuster le pH à 6,0. La suspension est égouttée et les formettes préparées ont une blancheur de 86,50 % ISO. Après une heure de vieillissement à 105°C, la blancheur est de 83,24 % ISO.1. The first sample is treated with SO₂ to adjust the pH to 6.0. The suspension is drained and the prepared formulas have a whiteness of 86.50% ISO. After one hour of aging at 105 ° C, the whiteness is 83.24% ISO.

2. Le second échantillon de pulpe est traité au CO₂ jusqu'à ajuster le pH à 6,3.2. The second pulp sample is treated with CO₂ until the pH is adjusted to 6.3.

Après égouttage, les formettes ont une blancheur de 87,16 % ISO.After draining, the formulas have a whiteness of 87.16% ISO.

Après vieillissement pendant 1 heure à 105°C, la blancheur est de 85,30 % ISO.After aging for 1 hour at 105 ° C, the whiteness is 85.30% ISO.

Cet exemple montre que l'ajustement du pH par CO₂ donne une plus forte blancheur que l'ajustement par SO₂. De plus, la reversion de blancheur est moindre quand le CO₂ est utilisé.This example shows that the adjustment of the pH by CO₂ gives a stronger whiteness than the adjustment by SO₂. In addition, the whiteness reversion is less when CO₂ is used.

Claims (4)

1. Procédé de fabrication de pâte à papier du type où le blanchiment comporte une phase H ou P juste avant le passage de la pâte blanchie dans l'épurateur et/ou la machine à papier, caractérisé en ce que l'on traite la pâte blanchie essentiellement à l'aide d'acide carbonique et directement après le traitement de blanchiment.1. A method of manufacturing paper pulp of the type where the bleaching comprises an H or P phase just before the passage of the bleached pulp through the scrubber and / or the paper machine, characterized in that the pulp is treated bleached mainly with carbonic acid and directly after the bleaching treatment. 2. Procédé selon la revendication 1, caractérisé en ce que l'acide carbonique est introduit sous forme de CO ₂ gazeux et/ou liquide dans les eaux de lavage.2. Method according to claim 1, characterized in that the carbonic acid is introduced in the form of gaseous and / or liquid CO ₂ into the washing waters. 3. Procédé selon la revendication 1, caractérisé en ce que l'acide carbonique est introduit sous forme de CO₂ gazeux et/ou liquide dans la suspension blanchie.3. Method according to claim 1, characterized in that the carbonic acid is introduced in the form of gaseous and / or liquid CO₂ in the bleached suspension. 4. Procédé selon l'une des revendications 1 à 3, caractérisé en ce que la pâte blanchie est de type mécanique,thermomécanique, chimico-thermomécanique, chimique ou provient du retraitement de papier désencré.4. Method according to one of claims 1 to 3, characterized in that the bleached pulp is of mechanical, thermomechanical, chemico-thermomechanical, chemical type or comes from the reprocessing of deinked paper.
EP88402223A 1987-09-08 1988-09-05 Process for producing a bleached paper pulp comprising a carbon dioxide treatment after bleaching Expired - Lifetime EP0307295B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88402223T ATE62287T1 (en) 1987-09-08 1988-09-05 PROCESS FOR PRODUCTION OF BLEACHED PAPER PULP BY MEANS OF POST-BLEACHING CARBON TREATMENT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8712451 1987-09-08
FR8712451A FR2620144B1 (en) 1987-09-08 1987-09-08 PROCESS FOR THE MANUFACTURE OF BLEACHED PAPER PULP INCLUDING TREATMENT WITH CARBONIC ACID AFTER BLEACHING

Publications (2)

Publication Number Publication Date
EP0307295A1 true EP0307295A1 (en) 1989-03-15
EP0307295B1 EP0307295B1 (en) 1991-04-03

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EP (1) EP0307295B1 (en)
JP (1) JPH01207492A (en)
KR (1) KR890005346A (en)
CN (1) CN1013131B (en)
AT (1) ATE62287T1 (en)
AU (1) AU608054B2 (en)
BR (1) BR8804619A (en)
DE (1) DE3862265D1 (en)
ES (1) ES2021857B3 (en)
FI (1) FI884123A (en)
FR (1) FR2620144B1 (en)
GR (1) GR3001730T3 (en)
MA (1) MA21393A1 (en)
NO (1) NO883968L (en)
NZ (1) NZ226060A (en)
OA (1) OA08949A (en)
PT (1) PT88435B (en)
ZA (1) ZA886622B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0562835A1 (en) * 1992-03-24 1993-09-29 ALBRIGHT & WILSON UK LIMITED Stabilisation of bleach liquors
WO1994021857A1 (en) * 1993-03-24 1994-09-29 Kamyr, Inc. Treatment of bleach plant effluents
US5639347A (en) * 1993-03-24 1997-06-17 Ahlstrom Machinery Inc. Method of controlling of metals in a bleach plant, using oxidation
WO2001083886A1 (en) * 2000-05-04 2001-11-08 Aga Aktiebolag A process for controlling microbial growth

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011113119A1 (en) * 2010-03-19 2011-09-22 Fibria Celulose S/A Process for the treatment of cellulose pulps, cellulose pulp thus obtained and use of biopolymer for treating cellulose pulps
CN104032611B (en) * 2014-06-23 2016-04-20 广西大学 A kind of dioxde pulp bleaching process

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1993265A (en) * 1933-02-28 1935-03-05 Merrimac Chemical Co Inc Manufacture of paper embodying alkaline earth metal carbonate fillers
FR2283989A1 (en) * 1974-09-03 1976-04-02 Ahlstroem Oy PROCESS FOR WASHING CELLULOSE PULPS FROM ALKALINE DIGESTION

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1993265A (en) * 1933-02-28 1935-03-05 Merrimac Chemical Co Inc Manufacture of paper embodying alkaline earth metal carbonate fillers
FR2283989A1 (en) * 1974-09-03 1976-04-02 Ahlstroem Oy PROCESS FOR WASHING CELLULOSE PULPS FROM ALKALINE DIGESTION

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0562835A1 (en) * 1992-03-24 1993-09-29 ALBRIGHT & WILSON UK LIMITED Stabilisation of bleach liquors
WO1994021857A1 (en) * 1993-03-24 1994-09-29 Kamyr, Inc. Treatment of bleach plant effluents
US5509999A (en) * 1993-03-24 1996-04-23 Kamyr, Inc. Treatment of bleach plant effluents
US5639347A (en) * 1993-03-24 1997-06-17 Ahlstrom Machinery Inc. Method of controlling of metals in a bleach plant, using oxidation
WO2001083886A1 (en) * 2000-05-04 2001-11-08 Aga Aktiebolag A process for controlling microbial growth

Also Published As

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NO883968L (en) 1989-03-09
PT88435B (en) 1992-10-30
CN1033664A (en) 1989-07-05
FR2620144A1 (en) 1989-03-10
FI884123A0 (en) 1988-09-07
AU608054B2 (en) 1991-03-21
ES2021857B3 (en) 1991-11-16
OA08949A (en) 1990-11-30
AU2196088A (en) 1989-03-09
BR8804619A (en) 1989-04-18
CN1013131B (en) 1991-07-10
ATE62287T1 (en) 1991-04-15
NO883968D0 (en) 1988-09-07
MA21393A1 (en) 1989-07-01
FR2620144B1 (en) 1989-12-08
ZA886622B (en) 1991-05-29
PT88435A (en) 1989-07-31
JPH0217678B2 (en) 1990-04-23
EP0307295B1 (en) 1991-04-03
JPH01207492A (en) 1989-08-21
GR3001730T3 (en) 1992-11-23
NZ226060A (en) 1991-02-26
KR890005346A (en) 1989-05-13
DE3862265D1 (en) 1991-05-08
FI884123A (en) 1989-03-09

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