WO2000008251A1 - Procede perfectionne de blanchiment de pate a papier - Google Patents

Procede perfectionne de blanchiment de pate a papier Download PDF

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Publication number
WO2000008251A1
WO2000008251A1 PCT/IB1998/001318 IB9801318W WO0008251A1 WO 2000008251 A1 WO2000008251 A1 WO 2000008251A1 IB 9801318 W IB9801318 W IB 9801318W WO 0008251 A1 WO0008251 A1 WO 0008251A1
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WO
WIPO (PCT)
Prior art keywords
bleaching
pulp
chlorine
ozone
chlorine dioxide
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.)
Ceased
Application number
PCT/IB1998/001318
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English (en)
Inventor
Ture Petter Magnus Tibbling
Arvind Kumar Agarwal
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.)
Asia Pulp and Paper Co Ltd
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Asia Pulp and Paper Co Ltd
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
Application filed by Asia Pulp and Paper Co Ltd filed Critical Asia Pulp and Paper Co Ltd
Priority to PCT/IB1998/001318 priority Critical patent/WO2000008251A1/fr
Priority to AU86426/98A priority patent/AU8642698A/en
Publication of WO2000008251A1 publication Critical patent/WO2000008251A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • 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
    • D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
    • D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
    • 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
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone

Definitions

  • the present invention relates to a method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp wherein the entering pulp is fed continuously in a bleaching line and bleached with a plurality of bleaching agents comprising ozone and at least one member of the group consisting of chlorine dioxide (D), chlorine (C), hypochlorite (H), acidic hydrogen peroxide (Pa), peracetic acid (PAA), persulfuric acid (Ca), and organic peroxides (RO).
  • a bleaching line a bleaching line and bleached with a plurality of bleaching agents comprising ozone and at least one member of the group consisting of chlorine dioxide (D), chlorine (C), hypochlorite (H), acidic hydrogen peroxide (Pa), peracetic acid (PAA), persulfuric acid (Ca), and organic peroxides (RO).
  • Chlorine and hypochlorite are common bleaching agents employed in the bleaching of pulp for cellulosic fibrous material, particularly chemical pulp. Unfortunately, in such a process these chlorine products readily form a variety of chlorinated organic compounds, which are known to have a significant detrimental impact on the environment and to leave readily detectable levels in the final bleached pulp, as well. Accordingly, there has been increasing resistance to the use of chlorine in pulp bleaching.
  • chlorinated organic compounds Another option to reduce the discharge of chlorinated organic compounds is to lower chlorine usage in the first stage of the bleaching process.
  • Two alternatives that produce no significant degradation of pulp properties have been commercially employed for this purpose. These are (a) extended delignification in the pulp cooking stage and (b) oxygen delignification. These alternatives, with proper extraction, reduce the lignin content of brown stock going into the bleach plant. Nonetheless, even greater reductions in chlorine usage may be necessary.
  • a third option to reduce production of chlorinated orga ⁇ vcs in the bleaching process is to substitute chlorine dioxide for chlorine. Chlorine dioxide is a relatively strong oxidant compared to chlorine. To achieve the same degree of delignification, it requires only about thirty-eight weight percent chlorine dioxide on the pulp compared with one hundred weight percent of chlorine.
  • the physical characteristics of a pulp can be denoted by means of a number of parameters.
  • the kappa number of a pulp is a measure of the lignin content.
  • the viscosity represents the average chain length of the cellulose and is an indication of its strength. For a bleached pulp of mixed hardwood with a brightness of 90 ISO, the viscosity ought to be above 600 SCAN units (dm 3 /kg) to achieve a desired strength.
  • a primary object of the present invention is to provide an improved method of bleaching pulp of cellulosic fibrous material which considerably reduces adsorbable organic halogen (AOX), but which still employs chlorine by-products from integrated chlorine dioxide generation plants.
  • Another object of the invention is to provide an improved method of bleaching pulp of cellulosic fibrous material which is more cost-effective relative to conventional bleaching processes.
  • a further object of the invention is to provide an improved method of bleaching pulp of cellulosic fibrous material which reduces the use of total active chlorine.
  • a still further object of the invention is to optimize the charges of bleaching agent admixtures, whether based on chlorine-containing chemicals or not.
  • the at least one member of the group of bleaching agents consisting of chlorine dioxide, chlorine, hypochlorite, acidic hydrogen peroxide, peracetic acid, persulfuric acid, and organic peroxides is applied more than once in conjunction with the ozone bleaching.
  • An example of such a sequence is the sequence (DZD).
  • the method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp is one in which the pulp," fed continuously through a bleaching line, is bleached with ozone and two or more members of the group of bleaching agents consisting of chlorine dioxide, chlorine, hypochlorite, acidic hydrogen peroxide, peracetic acid, persulfuric acid, and organic peroxides, wherein this bleaching occurs in a single stage and wherein this single stage does not contain an intermediate washing or extraction stage.
  • the ozone and at least one member of the group of bleaching agents are added sequentially.
  • the ozone is normally added last so as to set the redox potential in the reaction vessel.
  • a high shear mixer can be used to ensure sufficient mixing of the components.
  • Ozone can, however, be followed by chlorine dioxide without an intervening washing stage, for example, the bleaching sequences (DZD), (HZD), and (CZD), among others.
  • the present invention comprises a method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp, wherein the pulp, fed continuously through a bleaching line, is bleached with sequential applications of various chorine-based chemicals and ozone in a single stage and wherein this single stage does not contain an intermediate washing or extraction stage.
  • the present invention comprises a method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp, wherein the pulp, fed continuously through a bleaching line, is bleached with a mixture of chlorine and ozone in a single stage and wherein this single stage does not contain an intermediate washing or extraction stage.
  • the present invention comprises a method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp, wherein the pulp, fed continuously through a bleaching line, is bleached with sequential applications of various non-chlorine-based bleaching agents from the group of bleaching agents and ozone in a single stage and wherein this single stage does not contain an intermediate washing or extraction stage.
  • this single stage bleaching of the pulp takes place under conditions such that the redox potential of the pulp immediately after the admixture of each bleaching agent is brought down to a level of 0 to about 20 % of the original value of the redox potential prior to the addition of the subsequent bleaching agent.
  • the pH of the pulp remains within the range of about 2 to about 4.
  • bleaching agent is chlorine or hypochlorite; and one in which the bleaching agent is a mixture of chlorine and chlorine dioxide.
  • Further preferred embodiments are those in which chlorine is added prior to the addition of ozone; in which the mixture of chlorine and chlorine dioxide is added prior to the addition of ozone; and in which chlorine and chlorine dioxide are added prior to the addition of ozone.
  • Another preferred embodiment employs a first chlorine dioxide treatment, subsequent treatment of the pulp with ozone, and a second chlorine dioxide treatment, without any intervening washing or extraction.
  • the second chlorine dioxide treatment can occur either after removal of oxygen and residual ozone (by means of a blowtank) or without an intervening removal of oxygen and residual ozone.
  • This bleaching sequence can be represented as (DZD).
  • the pulp is treated with ozone at a pressure in excess of 1 bar overpressure and the bleaching is carried out at a temperature in the range of about 25° C. to about 70° C, more preferably about 45° C. to about 65° C.
  • the bleaching treatment can be followed by one or two alkali extractions, at least one of which may be reinforced with oxygen gas and/or hydrogen peroxide. These alkali extractions can be performed in sequence with the bleaching treatment without intermediate washing or performed in a separate stage preceded by washing. Subsequently, the pulp can be further bleached with chlorine dioxide or non-chlorine- based bleach chemicals, in one or more stages.
  • the bleaching treatment can be followed by one or two chelation steps, preferably employing EDTA. These chelation steps can be performed in sequence with the bleaching treatment without intermediate washing or performed in a separate stage preceded by washing. Subsequently, the pulp can be further bleached with chlorine dioxide in one or more stages.
  • the entering pulp can consist of oxygen-delignified pulp which has been cooked continuously.
  • the chlorine or hypochlorite is added in an amount of about 5-20 kg/ADMT, preferably about 5-10 kg/ADMT, calculated as active chlorine; in which the ozone is added in an amount of about 1-5 kg/ADMT, preferably about 2-4 kg/ADMT and in which chlorine dioxide is added for the ultimate bleaching in an amount of about 2-50 kg/ADMT, preferably about 5-20 kg/ADMT, calculated as active chlorine.
  • Figure 1 shows schematically a bleaching plant for carrying out a first embodiment of the present method
  • Figure 2 shows schematically a bleaching plant for carrying out a second embodiment of the present method
  • Figure 3 diagrams the brightness relative to the ClO charge for four different bleaching processes in the bleaching of mill, oxygen-delignified pulp
  • Figure 4 illustrates the viscosity relative to the brightness for four different bleaching processes in the bleaching of mill, oxygen-delignified pulp.
  • the present invention comprises a method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp, wherein the pulp, fed continuously through a bleaching line, is bleached with ozone and at least one member of the group of bleaching agents consisting of chlorine dioxide, chlorine, hypochlorite, acidic hydrogen peroxide, peracetic acid, persulfuric acid, and organic peroxides, wherein this bleaching occurs in a single stage and wherein this single stage does not contain an intermediate washing or extraction stage.
  • At least one member of the group of bleaching agents consisting of chlorine dioxide, chlorine, hypochlorite, acidic hydrogen peroxide, peracetic acid, persulfuric acid, and organic peroxides can be applied more than once in conjunction with the ozone bleaching.
  • the method of bleaching pulp of cellulosic fibrous material in the production of chemical pulp is one in which the pulp, fed continuously through a bleaching line, is bleached with ozone and two or more members of the group of bleaching agents consisting of chlorine dioxide, chlorine, hypochlorite, acidic hydrogen peroxide, peracetic acid, persulfuric acid, and organic peroxides, wherein this bleaching occurs in a single stage and wherein this single stage does not contain an intermediate washing or extraction stage.
  • the present process can also include oxidative lignin degradation; suppressed formation of chlorinated lignins; a multichemical oxidative attack on pitch and resins; radical scavenger protection of carbohydrates; a reductive sulfonation stage; and a bleaching process that essentially suppresses chlorination as a result of selection of an appropriate pH and redox potential.
  • the above bleaching process can be described as (HDZE), followed by (EPO)D(ED) bleaching so as to achieve a brightness of 90+ ISO.
  • a similar apparatus can be employed in other bleaching sequences corresponding to the present invention, which include, among others, the bleaching sequences (CDZE), (DCZE), (HCZE), (CHZE), (DZDE), and (DHZE).
  • the neutralization stage E can also be replaced, in another embodiment, with a D stage.
  • the D stage can also further comprise a chelate Q so that the sequence (PO)D(ED) can be used for final bleaching. This means that more hydrogen peroxide (5-20 kg of H 2 O 2 ptp) can be used in the pressurized peroxide stage.
  • Other embodiments of the bleaching process of the present invention also include, among others, (CZD), (CZP), (DZD), (HZP), and (HZD).
  • the pulp is homogeneously mixed in the first mixer with chlorine or chlorine dioxide and is then, after a relatively short period of time when the pH is lowered below, mixed with a carrier gas containing ozone.
  • This brief period of time may be from 10 seconds up to a few minutes, for example, 10 minutes.
  • 80% up to 100% of the chlorine will have reaetad with the pulp before the ozone in gaseous form is added.
  • the carrier gas may contain about 10 to 15 per cent by weight ozone. However, with improved methods in the future it may be possible to increase the amount of ozone, for example, up to about 20 per cent by weight.
  • the amount of ozone can be controlled by the choice of a suitable gas pressure. Specifically, the higher the gas pressure mixed into the pulp, the more ozone that is mixed in as well. Because the carrier gas is not consumed during the bleaching process, the carrier gas can be recovered, if desired.
  • hydrogen peroxide is employed as one of the bleaching agents, a small quantity of oxygen gas may be added to oxidize the easily-oxidized compounds in the pulp, permitting more efficient utilization of the hydrogen peroxide.
  • high-pressure steam may also be added in sufficient amount to increase the temperature of the pulp to about 60-90°C.
  • ClO 2 can be employed in the bleaching process.
  • pulp of medium consistency (a slurry of about 6-15% pulp) is fed from the supply tank to mixers 51 and 52, where the pulp is treated sequentially with chlorine dioxide and ozone, respectively.
  • the treated pulp is then passed to a blow tank 53, where excess oxygen and residual ozone is removed.
  • the pulp is then neutralized with a NaOH solution and passed to a diffuser tower 54, where the pulp is washed.
  • the pulp is treated with NaOH, hydrogen peroxide, oxygen, and steam and then passed to a reaction vessel 55, where the pulp undergoes pressurized oxygen treatment. From this stage, the pulp then passes to a wash-press 56 for washing and pressing. After pressing, the pulp then passes to a mixer 57, where chlorine dioxide is again added, and then on to a bleaching tower 58. The pulp is then further treated at mixer 59, where chlorine dioxide is again added, and then passed on to bleaching tower 60, where the mixture is extracted with alkali and treated with sulfite, prior to passing on to a storage tower.
  • This embodiment of the present bleaching process comprises a bleaching sequence with only two bleaching agents, and a washing stage at the conclusion.
  • bleaching processes corresponding to the present invention are (CZ), (ZC), (DZ), and (ZD), among others.
  • the ozone is added with the aid of a carrier gas containing about 10-13 per cent by weight ozone.
  • the pulp is treated with ozone at a pressure in excess of 1 bar over-pressure, preferably 5-10 bars over-pressure, depending on the ozone charge.
  • the sequence bleaching of pulp with chlorine dioxide and ozone, or alternatively vice versa, is performed at a temperature of 25-70°C, preferably 45-65°C.
  • the bleaching treatments of the present invention can be followed by one or more alkali extractions, at least one of which may be reinforced with oxygen gas and/or hydrogen peroxide.
  • the first alkali extraction is performed either in sequence with the bleaching treatments without intermediate washing or in a separate stage preceded by washing.
  • the supplied and treated pulp is preferably of medium consistency, about
  • pulp 6-15%, and suitably consists of oxygen-delignified pulp which has been digested continuously.
  • the pulp may have also been previously treated with ozone.
  • pulp of medium consistency (a slurry of about 6-15% pulp) is fed from a supply tank to mixers 51 and 52, where the pulp is treated sequentially with activated oxygen (O*) and ozone, respectively.
  • Activated oxygen (O*) includes bleaching agents such as acidic hydrogen peroxide, peracetic acid, persulfuric acid, and organic peroxides.
  • the treated pulp is then passed to a separator 53, where excess oxygen and ozone is removed.
  • the pulp is then neutralized with aqueous NaOH to a pH of about 5 to 6, treated with a chelating agent like EDTA, and passed to a washing tower 54, where the pulp is washed with white water and alkali.
  • the pulp is treated in a reductive sulfonation step (R), in which the pulp is treated with bisulfite and chelate.
  • R reductive sulfonation step
  • the pulp is treated with bisulfite and chelate, under neutral to slightly acidic conditions in a pressurized system for about 0.5 to 2 hours at about 90° to 120° C. a ⁇ d vith a final pH of about 2.5 to 5.
  • Such a step combines sulfonation, activation, and chelation in one step.
  • the treated pulp is then passed to a reaction vessel 55 where the pulp undergoes pressurized oxygen treatment. From this stage, the pulp then passes to a wash press 56 for washing and pressing. After pressing, the pulp then passes to a mixer 57 where the pulp is treated with a mixture of NaOH and H 2 O , corresponding to an EOP step, and then on to a bleaching tower 58. The pulp is then further treated at mixer 59, where mixture of NaOH and H 2 O 2 is again added, and then passed on to bleaching tower 60, where the mixture is treated with H 2 O 2 , prior to passing on to a storage tower.
  • the bleaching process described thus can be illustrated as follows: [O*(ZQ)](R/EOP)P(PO).
  • the process of the present invention can be also practiced in bleaching processes comprising (DZ)(EO)D(ED); (DZD)(EO)D(ED); (DZD)(EOP)DDP; (DZD)(EO)DDP; [DZ(D+Q)](PO)DDP; [DC(ZE)](EO)DD and [O*(ZQ)](R/EOP)DP.
  • the bleaching sequence (DZD)(EO)DD of the present invention provides adequate and sufficient charge of ClO 2 in the first stage, as well as enabling prestages such as (HZD), (DZ), (ZD), Z or D in the same bleaching line. Pulps approaching ECF pulps, with an AOX ⁇ 0.5 - 0.6 kg ptp, can thus be produced using hypochlorite from Cl 2
  • the bleaching sequence of the present invention provides many advantages and benefits relative to the prior art.
  • the use of ozone in the present pulp bleaching sequence results in lowered process costs, because the amount of chlorine employed in the bleaching process is reduced relative to conventional processes. Further, the use of the bleaching agents in a single stage, without an intervening washing or extracting stage, also reduces process costs.
  • the use of ozone in the pulp bleaching process provides a significant improvement in pulp quality.
  • the bleached yield of pulp from the present process is about 0.2 to 0.3 % higher than the conventional processes.
  • the viscosity of the pulp is improved by 20 to 40 SCAN units relative to pulps produced by the processes of the prior art.
  • the present bleaching process also results in superior beatability; there is a 10 to 20% lowering in the beating energy requirement with the pulp of the present invention relative to that of the prior art.
  • the pulp of the present process also has a 15% greater tear strength.
  • the present pulp possesses a lower resin and speck content; reduced AOX; and decreased dioxin content.
  • the pulp of the present process significantly reduces the impact of the bleaching process on the environment.
  • the present process yields a pulp with a greatly lowered content of chlorinated organics, having an AOX of 0.2 to 0.4 kilograms per ton of pulp. Further, the pulp has a significantly lowerOOD (chemical oxygen demand) content - 10 to 20% relative to conventional pulps.
  • OOD chemical oxygen demand
  • the effluent from the present process is environmentally more benign than those of conventional processes, in that it is essentially free of chlorine and permits a gradual move in the future to a bleaching process that is totally free of chlorine.
  • the present process will permit compliance with the stricter environmental regulations regarding chlorine anticipated in the near future.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

L'invention concerne un procédé de blanchiment de pâte à papier à base de matériau fibreux cellulosique servant dans la production de pâte à papier chimique, ce procédé consistant à alimenter en continu ce matériau dans une installation de blanchiment, à le blanchir à l'aide d'ozone et d'au moins un élément du groupe d'agents de blanchiment constitué par du dioxyde de chlore, du chlore, du peroxyde d'hydrogène acide, de l'acide peracétique, de l'acide persulfurique et des peroxydes organiques, et à exécuter ce blanchiment en une seule étape. Cette étape est caractérisée en ce qu'elle ne comporte pas d'étape intermédiaire de lavage ou d'extraction, en ce que le potentiel d'oxydoréduction de la pâte à papier, aussitôt après l'addition de chaque agent de blanchiment, est abaissé à un niveau de l'ordre de 0 à environ 20 % de la valeur originale dudit potentiel, avant l'ajout de l'agent de blanchiment ultérieur.
PCT/IB1998/001318 1998-07-31 1998-07-31 Procede perfectionne de blanchiment de pate a papier Ceased WO2000008251A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/IB1998/001318 WO2000008251A1 (fr) 1998-07-31 1998-07-31 Procede perfectionne de blanchiment de pate a papier
AU86426/98A AU8642698A (en) 1998-07-31 1998-07-31 An improved method for bleaching pulp

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB1998/001318 WO2000008251A1 (fr) 1998-07-31 1998-07-31 Procede perfectionne de blanchiment de pate a papier

Publications (1)

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WO2000008251A1 true WO2000008251A1 (fr) 2000-02-17

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PCT/IB1998/001318 Ceased WO2000008251A1 (fr) 1998-07-31 1998-07-31 Procede perfectionne de blanchiment de pate a papier

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2391011A (en) * 2002-07-19 2004-01-28 Crosmill Ltd Bleaching cellulose suspensions
WO2004052493A1 (fr) * 2002-12-06 2004-06-24 Institut National De La Recherche Agronomique (Inra) Procede de controle de la retention d'un compose organique au sein d’une phase liquide ou solide et applications du procede en agro-alimentaire
EP2052109A4 (fr) * 2006-07-21 2012-05-02 Nalco Co Compositions et procédés améliorés de production du papier
EP2224055A4 (fr) * 2007-12-20 2012-09-05 Mitsubishi Gas Chemical Co Procédé pour la production de pâte blanchie

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4039099A1 (de) * 1989-12-29 1991-07-04 Kamyr Ab Verfahren zum bleichen von cellulosebrei
FR2663348A1 (fr) * 1990-06-19 1991-12-20 Centre Tech Ind Papier Procede pour ameliorer le blanchiment des pates papetieres chimiques au moyen de l'ozone et pates ainsi traitees.
WO1992017639A1 (fr) * 1991-04-08 1992-10-15 International Paper Company Procede de reduction de matiere coloree d'un effluent de blanchiment en utilisant une sequence de blanchiment dzd
WO1994021856A1 (fr) * 1993-03-22 1994-09-29 Solvay Interox Procede ameliore de delignification d'un materiau lignocellulosique par l'ozone/peracide
FR2743094A1 (fr) * 1995-12-27 1997-07-04 Centre Tech Ind Papier Procede de blanchiment des pates a papier chimiques

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4039099A1 (de) * 1989-12-29 1991-07-04 Kamyr Ab Verfahren zum bleichen von cellulosebrei
FR2663348A1 (fr) * 1990-06-19 1991-12-20 Centre Tech Ind Papier Procede pour ameliorer le blanchiment des pates papetieres chimiques au moyen de l'ozone et pates ainsi traitees.
WO1992017639A1 (fr) * 1991-04-08 1992-10-15 International Paper Company Procede de reduction de matiere coloree d'un effluent de blanchiment en utilisant une sequence de blanchiment dzd
WO1994021856A1 (fr) * 1993-03-22 1994-09-29 Solvay Interox Procede ameliore de delignification d'un materiau lignocellulosique par l'ozone/peracide
FR2743094A1 (fr) * 1995-12-27 1997-07-04 Centre Tech Ind Papier Procede de blanchiment des pates a papier chimiques

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2391011A (en) * 2002-07-19 2004-01-28 Crosmill Ltd Bleaching cellulose suspensions
WO2004052493A1 (fr) * 2002-12-06 2004-06-24 Institut National De La Recherche Agronomique (Inra) Procede de controle de la retention d'un compose organique au sein d’une phase liquide ou solide et applications du procede en agro-alimentaire
EP2052109A4 (fr) * 2006-07-21 2012-05-02 Nalco Co Compositions et procédés améliorés de production du papier
EP3020861A1 (fr) * 2006-07-21 2016-05-18 Nalco Company Compositions améliorées et procédés de production de papier
EP2224055A4 (fr) * 2007-12-20 2012-09-05 Mitsubishi Gas Chemical Co Procédé pour la production de pâte blanchie
US8900408B2 (en) * 2007-12-20 2014-12-02 Mitsubishi Gas Chemical Company, Inc. Process for production of bleached pulp

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Publication number Publication date
AU8642698A (en) 2000-02-28

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