EP0925401B1 - Procede de blanchiment de pate a papier - Google Patents

Procede de blanchiment de pate a papier Download PDF

Info

Publication number
EP0925401B1
EP0925401B1 EP97919018A EP97919018A EP0925401B1 EP 0925401 B1 EP0925401 B1 EP 0925401B1 EP 97919018 A EP97919018 A EP 97919018A EP 97919018 A EP97919018 A EP 97919018A EP 0925401 B1 EP0925401 B1 EP 0925401B1
Authority
EP
European Patent Office
Prior art keywords
pulp
acid
stage
process according
acids
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.)
Expired - Lifetime
Application number
EP97919018A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0925401A1 (fr
Inventor
Johan Devenyns
Eric Chauveheid
Lucien Plumet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Solvay Chimie SA
Original Assignee
Solvay Interox SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from BE9600764A external-priority patent/BE1010617A3/fr
Priority claimed from BE9600858A external-priority patent/BE1010678A3/fr
Priority claimed from BE9600857A external-priority patent/BE1010677A3/fr
Application filed by Solvay Interox SA filed Critical Solvay Interox SA
Publication of EP0925401A1 publication Critical patent/EP0925401A1/fr
Application granted granted Critical
Publication of EP0925401B1 publication Critical patent/EP0925401B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • 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
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides

Definitions

  • chemical pulp By chemical pulp is meant the pulp having undergone a minor treatment in the presence of chemical reagents such as sulfide of sodium in an alkaline medium (kraft or sulphate cooking) or by others alkaline processes.
  • chemical reagents such as sulfide of sodium in an alkaline medium (kraft or sulphate cooking) or by others alkaline processes.
  • metal ions having an effect harmful are transition metal ions including, inter alia, manganese, copper and iron which catalyze reactive decomposition reactions peroxides. They degrade the peroxidized reagents used for the delignification and bleaching via radical mechanisms and increase thus the consumption of these products while reducing the properties mechanical pulp.
  • Removal of metal ions can be achieved by treatment with acid at room temperature from the pulp.
  • these treatments in acid medium removes not only harmful metal ions but also alkaline earth metal ions such as magnesium and calcium which have a stabilizing effect on the peroxidized reagents used and a beneficial effect on the optical and mechanical qualities of paper pulp.
  • WO-A-96/12063 proposes a method for destroying selectively 4-deoxy-b-L-threo-hex-4-enepyranosyluronic acid groups (hexeneuronic groups) by treating the paper pulp to a temperature between 85 ° C and 150 ° C and at a pH between 2 and 5.
  • the destruction of hexeneuronic groups reduces the kappa number from 2 to 9 units and non-selectively reduces the adsorption of transition metal ions and of alkaline earth metals.
  • EP-A-0 456 626 describes a process for bleaching paper pulp in which a chelation stage (stage Q) is carried out in a pH zone between 3.1 and 9.0 before treating the pulp with hydrogen peroxide (step P).
  • stage Q a chelation stage
  • step P hydrogen peroxide
  • Example 1 of this patent application shows that the whiteness maximum pulp after treatment with peroxide is ISO 66.1 ° and that it is reached when the pH of step Q is equal to 6.1. At higher pH, the whiteness of the paper pulp decreases rapidly, reaching only 61.9 ° ISO at pH 7.7 and 56.4 ° ISO at pH 9.1.
  • step Q the amount of peroxide of hydrogen consumed increases as well as the cost of production.
  • even a small change in pH during step Q has influences considerable on the quality and / or cost price of chemical paper pulp.
  • it is difficult to precisely control the pH when this one is close to neutral because the buffering capacity of the pulp suspension is relatively weak.
  • EP-A-0 456 626 describes a process for bleaching paper pulp in which a step of chelation (step Q) using aminocarboxylic chelating agents such as EDTA or DTPA is carried out in a pH zone between 3.1 and 9.0 before treating the pulp with hydrogen peroxide (step P).
  • a disadvantage of this process is linked to the use of chelating agents very powerful aminocarboxylates such as ethylenediaminetetraacetic acid (EDTA) or diethylenetriaminepentaacetic acid (DTPA).
  • EDTA ethylenediaminetetraacetic acid
  • DTPA diethylenetriaminepentaacetic acid
  • the purpose of the present invention is to provide a method of delignification and bleaching of chemical pulp which allows to expand the effective pH zone of the chelation (stage Q) prior to treatment with an oxidizer, without altering the whiteness of the paper pulp.
  • the pH of the paper pulp it is no longer necessary to strictly control the pH of the paper pulp during treatment with a chelating agent. In other words, even if at during the chelation the pH of the pulp varies, the result, i.e. the whiteness of the paper pulp obtained after the treatment step with an oxidant, is not affected. During chelation the pH can even be higher than 9. In general, the pH is less than or equal to 12.
  • the amount of oxidant consumed remains substantially constant in a wide pH range of chelation and is generally below that of known methods.
  • the pulp thus treated retains good properties. optical and mechanical in a wide pH range of chelation.
  • alkaline earth metal ions such as magnesium and calcium must be deposit or redeposit on the fibers to obtain a high ion ratio beneficial / harmful ions i.e. alkaline earth metal ions / metal ions of transition on the fibers. It is particularly important to be in the presence a high magnesium / manganese ratio on the fibers to avoid catalytic decomposition of the oxidant during the oxidant treatment step. This magnesium / manganese ratio on the fibers is preferably above of 30.
  • alkaline earth metal ions can be added, if necessary to the pulp suspension in order to increase the ion ratio of alkaline earth metals / transition metal ions on the fibers. If we wish to increase the magnesium / manganese ratio on the fibers, we can add magnesium to the pulp and preferably before adjusting the pH or in any case before the washing step (c).
  • Another advantage of this process is that it can avoid pH jumps when processing the pulp and thereby reducing the amount of reagents put in action. Indeed, after the acid treatment step aimed at reducing the amount of hexeneuronic acids, the pH of the paper pulp is adjusted by adding e.g. a base such as sodium hydroxide and paper pulp is then washed to to remove the chelated transition metal ions. The paper pulp therefore no longer has need to be acidified before chelation. Therefore, the amount of reagent implementation in the oxidizing treatment step in an alkaline medium is less.
  • a base such as sodium hydroxide
  • the acid treatment step (a) pulp is made at a pH above about 2.
  • the pH does not exceed 6.5.
  • the temperature of the acid treatment step (a) of the paper pulp is preferably above 85 ° C. It is advantageously less than 150 ° C.
  • acids such as inorganic acids eg sulfuric acid, nitric acid, hydrochloric acid and organic acids such as acid formic acid and / or acetic acid can be used to adjust the pH of the pulp suspension during the acid treatment step.
  • acids can be buffered eg with salts of acids such as formates to keep the pH as constant as possible throughout treatment.
  • the duration of the acid treatment step (a) depends on the pH, the temperature and the paper pulp used.
  • the acid treatment step (a) of the paper pulp is performed in the presence of an oxidant.
  • the acid treatment step (a) of the dough paper in the presence of an oxidant is carried out at a pH above about 2. From preferably the pH does not exceed 6.5.
  • the oxidant during the acid treatment step (a) with an oxidant can be chosen from chlorine, chlorine dioxide, ozone, peracids, peroxide of hydrogen and their mixtures.
  • peracids examples include peracetic acid, performic acid, permonosulfuric acid, their salts, in in particular the salt of permonosulfuric acid, and their mixtures.
  • the pH of the paper pulp is adjusted to a pH greater than or equal to 3 during the pH adjustment step (b).
  • the pH is preferably adjusted between 4 and 12 and particularly preferred between 7 and 12, respectively 10 and 12.
  • the step is not added during the step for adjusting the pH (b), ions of alkaline earth metals, in particular magnesium and calcium ions.
  • An additional washing step for the dough can be carried out after the pH adjustment step (b) and before adding the chelating agent, if necessary.
  • additional dough processing step is meant alkaline extractions, possibly reinforced by oxygen or else chlorine, chlorine dioxide or mixtures thereof.
  • the chelating agent can be chosen from aminocarboxylic acids, hydroxycarboxylic, phosphonic and their salts.
  • EDTA ethylenediaminetetraacetic
  • DTPA diethylenetriaminepentaacetic acid
  • DTMPA diethylenetriaminepentamethylenephosphonic acid
  • an aminocarboxylic chelating agent is used in a amount less than 0.4% compared to dry paper pulp.
  • An advantage of this first embodiment lies in the fact that the quantity of chelating agents discharged with effluents into rivers is reduced compared to conventional methods. Indeed, these classic processes in practice require approximately twice as many chelating agents to achieve same results. The risk to the environment caused by the solubilization of heavy metals from riverbed sediments is therefore minimized because the amount of chelating agents used is reduced.
  • step of acid treatment (a) aimed at reducing the quantity of hexeneuronic acids in the dough to a pH adjustment before washing the dough reduces significantly the amount of chelating agents used. She is advantageously less than or equal to 0.3%, in particular less than or equal to 0.2% compared to dry paper pulp.
  • EDTA ethylenediaminetetraacetic acid
  • DTPA acid diethylenetriaminepentacetic
  • a biodegradable chelating agent In a second embodiment of the method according to the invention, it is uses a biodegradable chelating agent.
  • This embodiment allows you to control the profile of metal ions in the pulp without having to use chelating agents which are difficult or non-biodegradable. She allows the use of biodegradable chelating agents which have properties weaker chelating agents which would have been ineffective in processes conventional for bleaching chemical pulp.
  • agent biodegradable chelating agent means a chelating agent capable of being degraded by living organisms.
  • the optimal pH during treatment with the chelator and more precisely the pH optimal pH adjustment step is towards the alkaline zone, where the capacity dough suspension buffer is higher, which greatly facilitates pH control in the conduct of this process compared to the processes known.
  • a step of acid treatment (a) aimed at reducing the quantity of hexeneuronic acids in the dough to pH adjustment before washing the dough allows the use of agents weaker chelating agents which are therefore more easily biodegradable.
  • the second embodiment allows the use of liqueurs from a bleaching and delignification step for paper pulp rich in fragments of oxidized carbohydrates either directly or indirectly as a source of biodegradable chelating agents.
  • the second embodiment it is possible to recycle the liqueurs from the oxidation stage (d) and add them directly to the acid suspension to adjust the pH thereof.
  • Residual oxidizing reagents such as ozone, hydrogen peroxide or peracids contained in this liquor can act on paper pulp. The effectiveness of the process is therefore improved.
  • the pH adjustment step (b) can advantageously be combined with the application of oxidizing reagents such as oxygen and hydrogen peroxide, in an alkaline medium.
  • a washing step additional dough can be made, if necessary after the step pH adjustment (b) and before adding the biodegradable chelating agent.
  • the agents preferred chelating agents are polyhydroxycarboxylic acids containing only 1 carboxylic group.
  • the oxidant of the treatment step with an oxidant (d) is advantageously chosen from hydrogen peroxide, the peracids and ozone.
  • hydrogen peroxide is used in an alkaline medium, ie under conventional conditions either at high temperature and pressure.
  • This oxygen pulp treatment step can be presented as a step O, Op, Eo, Eop in which O represents a step with pressurized oxygen, Op an oxygen step reinforced with pressurized hydrogen peroxide, Eo an alkaline extraction step reinforced with oxygen, Eop a step extraction reinforced with oxygen and hydrogen peroxide.
  • the acid treatment step to reduce the amount of acids hexeneuronics present in the paper pulp must make it possible to remove a large fraction of hexeneuronic groups, i.e. at least 10% of them.
  • the amount of hexeneuronic acids is generally reduced by at least minus 15%, especially at least 20%. Reduced quantities of at least 25%, and more particularly at least 30% are preferred. Results particularly favorable are obtained with quantities reduced by at least 35%, especially 40%. Quantities reduced by at least 50% are all particularly preferred.
  • the pulp is treated in the presence of water to a consistency of 0.1 to 50% by weight and preferably from 1 to 20% by weight.
  • the process according to the invention can be used in sequences of delignification and bleaching aimed at reducing the amount of elemental chlorine, elemental chlorine-free (ECF) bleaching sequences or totally chlorine-free sequences (TCF) or in sequences aimed at minimizing water consumption, eg by recycling effluents. he allows, in these types of sequences, to more easily achieve the objective of reducing the amount of chlorine or chlorine dioxide to achieve a same level of whiteness.
  • ECF elemental chlorine-free
  • TCF totally chlorine-free sequences
  • a method of delignification and bleaching of chemical paper pulp including the steps : A (Q) N (Q) W P in which step A represents a step for processing the acid paper pulp to reduce the amount of hexeneuronic acids, N represents a step of adjusting the pH in order to deposit or redeposit the ions of alkaline earth metals on the dough, (Q) represents the addition of a chelating agent which is done before or during step A and / or before, during or after step N for pH adjustment, W represents a step for washing the paper pulp and P represents an oxidation step.
  • oxidants sensitive to transition metals is meant reagents that decompose on contact with transition metals such as hydrogen peroxide, peracids and ozone.
  • the present delignification and laundering process pulp can be combined with any other conventional bleaching step y included in steps using enzymes or chlorinated reagents such than chlorine and chlorine dioxide.
  • wood used for the production of chemical pulp are suitable for the implementation of the present process and in particular those used for kraft pulp, namely softwoods such as p. ex. the various pine and fir species and hardwoods such as birch, beech, oak, hornbeam and eucalyptus.
  • Figure 1 shows the whiteness expressed in ISO degree of a paper subjected to an A N Q W P treatment and that of a paper pulp having undergone conventional Q W P treatment i.e. without acid treatment or neutralization.
  • Figure 2 shows the consumption of hydrogen peroxide as a function of the pH during the chelation of a paper pulp subjected to an A N Q W treatment P or a Q W P treatment.
  • Q W P treatment the consumption of hydrogen peroxide is higher and goes through a minimum which is between pH 4 and 6.
  • a N Q W P treatment the consumption of hydrogen peroxide is lower.
  • the consumption of hydrogen peroxide remains at a lower value for pH between 4 and 10 during chelation.
  • the treatment of paper pulp according to the present process therefore allows obtain paper pulps with better optical properties and mechanical and this with a reduced consumption of hydrogen peroxide.
  • Figure 3 shows the whiteness expressed in ISO degree of a paper pulp subjected to an A N Q W P treatment and that of a pulp that has undergone conventional Q W P treatment i.e. without acid treatment or neutralization depending on the amount of EDTA.
  • a hardwood pulp with a starting pH of 10.5 and a consistency of 37.6% by weight was subjected to a delignification treatment and bleaching A N Q W P.
  • a paper pulp with a starting pH of 10.5 and a consistency of 37.6% by weight, a whiteness of 48.2 ° ISO and a Kappa Index of 11.2 was subject to delignification and bleaching treatment A N Q W P.
  • a paper pulp with a starting pH of 8.5 and a consistency of 24.6% by weight, a whiteness of 60.3 ° ISO and a Kappa Index of 5.4 was subjected to a conventional delignification and bleaching treatment Q W P and to comparison to treatment A N Q W P.
  • the first four tests were carried out using a delignification and conventional bleaching comprising a chelation step and an oxidation step using hydrogen peroxide in an alkaline medium (Q W P).
  • the chelation was carried out at room temperature for 30 minutes at pH values between pH 3 and pH 11. 1% by weight of glucoheptonate was used as a chelating agent.
  • the hydrogen peroxide oxidation of the paper pulp was carried out in alkaline medium at 90 ° C for 120 minutes.
  • the density of the samples has been adjusted to 4% and an identical amount of glucoheptanoate was added to each sample and acted at 30 ° C for 30 minutes.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Coloring Foods And Improving Nutritive Qualities (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)
EP97919018A 1996-09-11 1997-08-23 Procede de blanchiment de pate a papier Expired - Lifetime EP0925401B1 (fr)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
BE9600764A BE1010617A3 (fr) 1996-09-11 1996-09-11 Procede de blanchiment de pate a papier.
BE9600764 1996-09-11
BE9600858 1996-10-11
BE9600857 1996-10-11
BE9600858A BE1010678A3 (fr) 1996-10-11 1996-10-11 Procede de delignification et de blanchiment de pate a papier chimique.
BE9600857A BE1010677A3 (fr) 1996-10-11 1996-10-11 Procede de delignification et de blanchiment de pate a papier chimique.
PCT/EP1997/004758 WO1998011295A1 (fr) 1996-09-11 1997-08-23 Procede de blanchiment de pate a papier

Publications (2)

Publication Number Publication Date
EP0925401A1 EP0925401A1 (fr) 1999-06-30
EP0925401B1 true EP0925401B1 (fr) 2002-01-16

Family

ID=27159855

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97919018A Expired - Lifetime EP0925401B1 (fr) 1996-09-11 1997-08-23 Procede de blanchiment de pate a papier

Country Status (18)

Country Link
US (1) US6123809A (et)
EP (1) EP0925401B1 (et)
JP (1) JP2001503109A (et)
AT (1) ATE212087T1 (et)
AU (1) AU4300797A (et)
BR (1) BR9711743A (et)
CA (1) CA2265566A1 (et)
CZ (1) CZ86099A3 (et)
DE (1) DE69709656T2 (et)
EE (1) EE03881B1 (et)
ES (1) ES2171926T3 (et)
ID (1) ID19415A (et)
MY (1) MY132667A (et)
NO (1) NO991153L (et)
PL (1) PL332079A1 (et)
PT (1) PT925401E (et)
RU (1) RU2189412C2 (et)
WO (1) WO1998011295A1 (et)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1012675A6 (fr) * 1999-05-11 2001-02-06 Solvay Procede de blanchiment de pate a papier.
US6702921B2 (en) * 2001-05-01 2004-03-09 Ondeo Nalco Company Methods to enhance pulp bleaching and delignification using an organic sulfide chelating agent
AU2002356030A1 (en) * 2001-08-13 2003-03-03 Vanderbilt University Distribution of solutions across a surface
US7351764B2 (en) * 2004-03-31 2008-04-01 Nalco Company Methods to enhance brightness of pulp and optimize use of bleaching chemicals
CA2569848C (en) * 2004-06-08 2011-05-10 Nippon Paper Industries Co., Ltd. Pulp bleaching processes
US20060201642A1 (en) * 2005-03-08 2006-09-14 Andritz Inc. Methods of treating chemical cellulose pulp
US20070131364A1 (en) * 2005-12-14 2007-06-14 University Of Maine Process for treating a cellulose-lignin pulp
US20100224336A1 (en) * 2005-12-14 2010-09-09 University Of Maine System Board Of Trustees Process of bleaching a wood pulp
JP4893210B2 (ja) * 2006-10-03 2012-03-07 三菱瓦斯化学株式会社 漂白パルプの製造方法
JP4973284B2 (ja) * 2007-03-30 2012-07-11 栗田工業株式会社 パルプ洗浄剤、パルプ製造方法、及びパルプ洗浄方法
CA2728278C (en) 2008-06-20 2016-06-28 Zheng Tan Composition and recording sheet with improved optical properties
FR3016359B1 (fr) * 2014-01-10 2022-04-29 Arkema France Compositions de peroxyde d'hydrogene pour la delignification de matiere vegetale et leurs utilisations
CN104313933A (zh) * 2014-09-23 2015-01-28 华南理工大学 一种硫酸盐蔗渣浆绿色漂白方法
FR3062138B1 (fr) * 2017-01-23 2019-06-07 Centre Technique De L'industrie Des Papiers, Cartons Et Celluloses Procede de blanchiment d'une pate a papier

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE500113C2 (sv) * 1992-07-09 1994-04-18 Kamyr Ab Sätt vid blekning av massa för omhändertagande av utlösta metaller
SE9301160L (sv) * 1992-08-28 1994-03-01 Sunds Defibrator Ind Ab Förfarande för behandling av processvatten
EP0622491B2 (en) * 1993-04-20 2002-07-17 Eka Chemicals AB Method for bleaching lignocellulose-containing pulp
US5571378A (en) * 1993-11-23 1996-11-05 Hampshire Chemical Ltd. Process for high-pH metal ion chelation in pulps
SE504826C2 (sv) * 1994-10-07 1997-05-12 Sunds Defibrator Ind Ab Behandling av kemisk massa med komplexbildare i närvaro av ett oxidationsmedel
WO1996025552A1 (en) * 1995-02-17 1996-08-22 Ahlstrom Machinery Oy Method of pretreating pulp to be bleached with peroxide

Also Published As

Publication number Publication date
EP0925401A1 (fr) 1999-06-30
ES2171926T3 (es) 2002-09-16
EE03881B1 (et) 2002-10-15
NO991153L (no) 1999-05-04
NO991153D0 (no) 1999-03-10
BR9711743A (pt) 1999-08-24
PL332079A1 (en) 1999-08-30
PT925401E (pt) 2002-07-31
US6123809A (en) 2000-09-26
DE69709656T2 (de) 2002-10-17
EE9900119A (et) 1999-10-15
RU2189412C2 (ru) 2002-09-20
MY132667A (en) 2007-10-31
AU4300797A (en) 1998-04-02
ATE212087T1 (de) 2002-02-15
ID19415A (id) 1998-07-09
CZ86099A3 (cs) 1999-06-16
DE69709656D1 (de) 2002-02-21
CA2265566A1 (fr) 1998-03-19
JP2001503109A (ja) 2001-03-06
WO1998011295A1 (fr) 1998-03-19

Similar Documents

Publication Publication Date Title
EP0925401B1 (fr) Procede de blanchiment de pate a papier
EP2761081B1 (fr) Pretraitement enzymatique de bois dans un procede de fabrication de pate a papier mecanique
FR2467261A1 (fr) Blanchiment de matiere lignocellulosique au moyen d'agents de blanchiment contenant du peroxyde
EP0496671B1 (fr) Traitement enzymatique d'une pâte ligno-cellulosique chimique
BE1004674A3 (fr) Procede pour le blanchiment d'une pate a papier chimique et application de ce procede au blanchiment d'une pate kraft.
BE1012675A6 (fr) Procede de blanchiment de pate a papier.
FR2910027A1 (fr) Procede de blanchiment des pates papeteries chimiques par traitement final a l'ozone a haute temperature
EP3008240B1 (fr) Procede de traitement des pates papetieres chimiques par traitement a l'ozone en presence d'ions magnesium
BE1010677A3 (fr) Procede de delignification et de blanchiment de pate a papier chimique.
BE1010617A3 (fr) Procede de blanchiment de pate a papier.
BE1010678A3 (fr) Procede de delignification et de blanchiment de pate a papier chimique.
BE1010679A3 (fr) Procede de delignification et de blanchiment de pate a papier chimique.
BE1011784A3 (fr) Procede de blanchiment de pate a papier.
CA2157291A1 (fr) Procede pour la delignification d'une pate a papier chimique
BE1007700A3 (fr) Procede pour le blanchiment d'une pate a papier chimique.
BE1010880A3 (fr) Procede de fabrication de pate a papier chimique.
BE1007757A3 (fr) Procede pour le blanchiment d'une pate a papier chimique.
CA1128260A (fr) Procede de fabrication de pates papetieres chimiques
WO1999046441A1 (fr) Procede de blanchiment et/ou de delignification de pates a papier
BE1005800A3 (fr) Procede pour la delignification et le blanchiment d'une pate a papier chimique.
EP0180529B2 (fr) Procédé pour la préparation des pâtes papetières chimiques en vue du blanchiment
FR2747406A1 (fr) Procede de delignification a l'oxygene d'une pate a papier
FR2670513A1 (fr) Procede de blanchiment des pates papetieres chimiques par traitement a l'oxygene en deux stades.
BE503145A (et)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19990412

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE DE ES FI FR PT SE

AX Request for extension of the european patent

Free format text: LT PAYMENT 19990412;LV PAYMENT 19990412

17Q First examination report despatched

Effective date: 19990729

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE DE ES FI FR PT SE

AX Request for extension of the european patent

Free format text: LT PAYMENT 19990412;LV PAYMENT 19990412

LTIE Lt: invalidation of european patent or patent extension
REF Corresponds to:

Ref document number: 212087

Country of ref document: AT

Date of ref document: 20020215

Kind code of ref document: T

REF Corresponds to:

Ref document number: 69709656

Country of ref document: DE

Date of ref document: 20020221

REG Reference to a national code

Ref country code: PT

Ref legal event code: SC4A

Free format text: AVAILABILITY OF NATIONAL TRANSLATION

Effective date: 20020416

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2171926

Country of ref document: ES

Kind code of ref document: T3

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030430

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20040806

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20040811

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FI

Payment date: 20040812

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: PT

Payment date: 20040820

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20040825

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20040902

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20041021

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050823

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050823

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050824

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050831

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060223

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060301

EUG Se: european patent has lapsed
REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20050824

BERE Be: lapsed

Owner name: S.A. *SOLVAY INTEROX

Effective date: 20050831