WO1995031599A1 - Procede de preparation de pates a papier chimiques delignifiees et blanchies - Google Patents
Procede de preparation de pates a papier chimiques delignifiees et blanchies Download PDFInfo
- Publication number
- WO1995031599A1 WO1995031599A1 PCT/FR1995/000494 FR9500494W WO9531599A1 WO 1995031599 A1 WO1995031599 A1 WO 1995031599A1 FR 9500494 W FR9500494 W FR 9500494W WO 9531599 A1 WO9531599 A1 WO 9531599A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- treatment
- weight
- hydrogen peroxide
- pressure
- temperature
- Prior art date
Links
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
-
- 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
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
Definitions
- the invention relates to a process for preparing delignified and bleached chemical paper pulp.
- Chemical paper pulps or chemical pulps are those obtained by cooking lignocellulosic materials, in particular wood.
- chemical pastes we distinguish:
- softwoods such as various species of pine and fir
- - hardwoods such as birch, poplar, beech and eucalyptus, for example.
- the chemical pulps obtained by cooking are subjected to several stages of delignifying treatment and / or bleaching.
- the first steps consist in perfecting the delignification resulting from cooking.
- the following steps are bleaching steps.
- the pasta After these delignifying and bleaching treatments, the pasta must usually have a whiteness of at least 88-90 ° ISO and a very low kappa index while retaining good mechanical properties, that is to say without significant degradation. cellulose. This degradation is detectable by measuring the viscosity of the dough or its degree of polymerization (DP). The PD should be kept as high as possible.
- the first significant steps are usually carried out by treatments with chlorine gas or chlorine dioxide.
- This article shows in particular the comparative delignification and bleaching powers of a series of reagents such as chlorine, chlorine dioxide, oxygen, ozone, hydrogen peroxide and also indicates the results generally obtained in term of kappa index, whiteness and viscosity.
- oxygen alone has a capacity for delignification and not appreciably for bleaching.
- Its chlorine replacement factor (CRF) is 5 and its use results in a reduction of approximately half of the kappa index (17 from 35), the viscosity obtained being 980 dm-Vkg (approximately 37 cps) and the whiteness of 34 ° ISO.
- Treatment with hydrogen peroxide makes it possible to whiten only pulps whose kappa number is less than 5 and whose manganese content is less than or equal to 3 ppm. and whose consistency is at least 25% by weight of dry matter relative to the total weight of the dough.
- This treatment with H 2 O 2 is carried out at a claimed temperature between 50 and 140 ° C.
- This manganese content less than or equal to 3 p.p.m. is obtained by a pretreatment with an acid or a complexing or sequestering agent in an acid medium.
- the temperatures exemplified are 80, 90 and 120 ° C. At this temperature of 120 ° C., there is no indication of the pressure prevailing in the reaction medium.
- This pressure could be the saturated water vapor pressure at the indicated temperature.
- EP0578304A1 using a chemical pulp with a consistency of 30% show that the DP decreases from 1180 to 1030 when the final whiteness increases from 89.8 to
- Patent application EP0577157A2 describes a process for bleaching a pulp having a consistency of 5 to 20%, with hydrogen peroxide in an alkaline medium, at a pressure of less than 25 bars and preferably less than 14 bars.
- the object of the present invention is to provide a process for the preparation of delignified and bleached chemical paper pulps having a high DP, by using oxygen and hydrogen peroxide as oxidizing agents and by carrying out all the stages of treatment of the process in reaction media at basic pH.
- the aim of this process is also to avoid any step using a chlorinated derivative such as, for example, chlorine or chlorine dioxide, and also to avoid any step of treatment with other oxidizing agents, in particular ozone or peracids.
- This object is achieved according to the present invention by a process for the preparation of delignified and bleached chemical paper pulp according to which a lignocellulosic pulp obtained by baking is subjected to the sequence of the following treatments:
- a treatment with hydrogen peroxide characterized in that the treatment with hydrogen peroxide is carried out in the presence of alkali metal silicate, at a temperature t greater than 100 ° C. and at a pressure p greater at 1.5 times the pressure of the saturated water vapor at temperature t.
- Oxygen treatment (a) or oxygen delignification is now widely used in the paper industry and in particular for the preparation of TCF and ECF pulps as indicated for example in the article by "Van Lierop, B, Oxygen delignification, Workshop on Emerging Pulping and Chlorine-free Technology, RALEIGH NC, March 1-4, 1993) ".
- step (a) of the process according to the invention are those known and used in the paper industry.
- One or more washing steps of the paste can be added at the end of the oxygen treatment in an alkaline pH medium.
- the oxygen treatment can also be carried out in several successive oxygen stages, separated by washing stages.
- the complexing or sequestering treatment (b) according to the present invention is carried out using a complexing or sequestering agent for transition metals, such as for example DTPA, (sodium diethylenetriaminepentaacetate), EDTA (sodium ethylenediaminetetraacetate), salts of phosphonic acids.
- DTPA sodium diethylenetriaminepentaacetate
- EDTA sodium ethylenediaminetetraacetate
- salts of phosphonic acids such as for example DTPA, (sodium diethylenetriaminepentaacetate), EDTA (sodium ethylenediaminetetraacetate), salts of phosphonic acids.
- the amount of complexing or sequestering agent is from 0.1% to 1% by weight relative to the dry matter contained in the dough. Preferably this amount is from 0.25 to 0.5%.
- the quantities of the products and reagents, unless otherwise specified, are always expressed in percent by weight relative to the weight of the dry matter of the pulp or of the pulp considered in the dry state.
- the consistency of the dough is expressed in percent by weight of dry matter relative to the total weight of the dough.
- treatment b) is carried out in a medium having an alkaline pH.
- the pH of the paste during the treatment b) is greater than 7 and less than or equal to 12.5.
- the pH in b) is from 8.5 to 9.5.
- the alkaline pH during the treatment in b) is obtained either by the residual alkalinity of the pulp at the end of the oxygen treatment, or by the alkalinity of the complexing or sequestering agent, or even by the addition of a base, for example NaOH.
- the manganese content of the pulp before the treatment with hydrogen peroxide c) does not exceed 5 p.p.m. by weight relative to the weight of dry matter of this same pulp.
- the temperature of treatment b) is generally from 20 to 100 ° C and the preferred temperature from 60 to 90 ° C.
- the duration of the treatment b) is generally from 1 to 30 minutes and preferably from 5 to 15 minutes.
- the consistency of the dough during processing b) is generally 2 to 25% and the preferred consistency is 4 to 12%.
- the paste is washed with water. Washing is carried out according to techniques known in the paper industry with hot or cold water. Surprisingly, the fact of carrying out the treatment c) under pressure makes it possible to minimize the attack on the cellulosic material of the pulp, and to keep a high DP, unlike the results obtained in the prior art.
- the kappa index of the paste before treatment with hydrogen peroxide does not exceed 17.
- the process then makes it possible, in a final step P, to obtain a delignified paste and of high whiteness usable directly for the manufacture. paper.
- the pressure p is from 5 to 200 bars absolute. This pressure range makes it possible to observe an advantage over the maintenance of a high DP when carrying out the method according to the invention.
- the pressure p is from 25 to 50 bars absolute.
- the alkali metal silicate is sodium silicate.
- sodium silicate it is preferred for reasons of convenience, to use from 0.5 to 10% by weight of a commercial solution at 38 ° Bé relative to the weight of the dry matter, and better still from 4 to 8% by weight of this solution.
- reaction temperature t is from 110 ° C to 180 ° C.
- the preferred range of t is 130 ° C to 160 ° C.
- the dough during the treatment with hydrogen peroxide, has a consistency of 4 to 35% by weight of dry matter relative to the total weight of the wet dough.
- the process can be carried out efficiently at low consistencies of about 4 to about 10% and the very fluid reaction medium can be easily displaced by pumping while avoiding any clogging.
- the consistency is 10 to 20%. This consistency range optimizes the yield of the process.
- the treatment with hydrogen peroxide has a duration of 1 minute to 3 hours.
- the duration varies in opposite direction to the increase in temperature.
- the duration is from 15 minutes to 1 hour. These relatively short durations allow the hourly output of the manufacture of delignified and bleached pulp to be increased.
- the hydrogen peroxide is used in an amount of 0.5 to 10% by weight relative to the weight of the dry matter of the paste.
- step c) of delignification and blanching according to the invention is carried out in a continuous or discontinuous manner (batch) by means of the devices generally used in the paper industry for cooking pasta and allowing to maintain the paste impregnated with the aqueous solution of hydrogen peroxide and sodium silicate, at a high pressure and at a high temperature for the chosen period.
- this treatment c) the dough is decompressed, cooled and washed with water.
- batch bleaching of the high consistency dough (20 to 30%) can be carried out as follows:
- the paste is mixed cold with hydrogen peroxide and sodium silicate and water so as to obtain the chosen consistency, then introduced into a stainless steel autoclave so as to fill it as completely as possible. After closing the autoclave, a small amount of water is pumped until a pressure of ten bars is obtained, then the temperature is brought to the chosen temperature for the selected time.
- This increase can be controlled by the flow of a little of the liquid phase during heating.
- continuous bleaching of low consistency dough (8-10%) can be done as follows:
- the DTPA pretreated paste is washed and mixed with hydrogen peroxide, silicate and water to have a consistency of 8 to 10% allowing the paste to be pumpable.
- the mixture is then introduced under pressure, by a high pressure pump into the reactor via a heat exchanger which brings the mixture to the chosen temperature.
- a heat exchanger which brings the mixture to the chosen temperature.
- the length of which is calculated so as to ensure the duration of the bleaching chosen, the bleached pulp is decompressed and cooled by dilution with water and then is washed.
- Ancillary devices such as heat exchangers and steam recovery cyclones can be added to recover and enhance the heat and pressure of the pulp after bleaching.
- the preferred embodiment of the present invention provides a new basic OQ sequence -P, step P being new in itself.
- This preferred sequence has technical advantages because in the techniques of the prior art it is necessary to carry out a complexation or sequestration of the metals in an acid medium in order to be able to carry out bleaching at high degrees, with hydrogen peroxide.
- Patent application EP578304A shows that treatment in an acidic medium at controlled pH is necessary before being able to carry out the final step with hydrogen peroxide. All the examples of EP578304 state a complexing treatment at acid pH or else an acid washing at pH 5 before the final bleaching.
- the preferred embodiment of the present invention makes it possible to obtain excellent results in terms of bleaching without requiring an acid medium in step b) contrary to the general teaching of the prior art.
- this preferred sequence makes it possible to eliminate the problems of corrosion in an acid medium of steel equipment and reduces the problems concerning the treatment of acids and residual salts for the respect of the environment.
- Step c) carried out according to the characteristics of the invention makes it possible, thanks to the use of a pressure p greater than the saturated steam pressure, to avoid any significant evaporation of the liquid reactants.
- the process according to the present invention therefore makes it possible to obtain the almost complete delignification and bleaching of chemical pulps after cooking in only 3 steps and using only inexpensive oxidizing agents, namely oxygen and hydrogen peroxide.
- Examples 1 to 46 which appear in Tables I to X were carried out from three chemical pastes of industrial origin obtained by kraft cooking and treatment with oxygen.
- the oxygen treatment of the pasta was carried out according to conventional conditions at 10% consistency, under an oxygen pressure of 3.5 bars, at a temperature of 95 ° C. and for a period of 60 to 90 minutes depending on the nature of the wood.
- the paste chosen from Table A is suspended at 10% consistency with 0.5% DTPA (commercial solution at 40% by weight of sodium DTPA in water) and heated for 15 minutes (0.25 hours) to 90 ° C.
- DTPA commercial solution at 40% by weight of sodium DTPA in water
- the final pH is 9 to 9, 6 depending on the paste chosen.
- the chosen paste is then filtered and washed with demineralized water
- the paste collected in a) is mixed at room temperature with the charge of hydrogen peroxide, sodium silicate and demineralized water necessary to obtain the consistency chosen for the test, then the reaction medium thus obtained is placed in a autoclave in stainless steel which is completely filled with dough, reducing the dead space as much as possible. A few cm 3 of demineralized water are pumped into the autoclave to reach the chosen pressure. The autoclave is then heated to temperature t for the duration chosen. Heating has the effect of increasing the internal pressure. In order to maintain the pressure at the chosen reaction value, the autoclave closing valve is intermittently opened to allow a few cm 3 of liquid to escape. After reaction, the autoclave is cooled and opened, the paste is collected on a filter and washed with demineralized water. The whiteness, the kappa index and the DP are then measured according to the ISO standards of the paper industry, mentioned above.
- Table I shows the comparative tests 1, 2,
- Table II shows tests 6, 7, 8, 9, 11, 10, 12 and 13 carried out on the KFII paste.
- Curve 2 for example shows that for a temperature of 150 ° C. and at 25 bars the addition of 2% silicate makes it possible to gain 10 ISO whiteness points.
- test 1 compare 0% silicate
- test 4 8% silicate
- Table III shows the tests 14, 15, 16, 17, 18, 19, 4, 20, 21, carried out on the KFI dough.
- Curves 5 and 6 also show that for the same paste and for otherwise identical conditions, an increase in temperature increases the whiteness.
- Table V shows the tests 28, 4, 29, 30 carried out on the KFI dough.
- Table VI shows the tests carried out on the KFII paste (tests 31, 32, 33, 34, 35).
- Table VII shows tests carried out on the KFI paste (tests 36, 37, 20, 38).
- Table VIII shows tests carried out on the KFI paste (tests 39, 21, 40, 2, 41, 45, 46).
- Table IX shows tests carried out on the KR paste (tests 42, 43, 44).
- Test 38 of Table VII carried out at low temperature but at high pressure gives, for the same quantities of reagents, a better whiteness (81.9 ° ISO) but much lower than that obtained by the conditions of the present invention (test 31 of table VI, 150 ° C, 100 bar, 88.6 ° ISO).
- Table IX shows the tests carried out on KR softwood kraft pulp with very low initial whiteness 34.5 ° ISO.
- Test 43 shows that with 4% H 2 O 2 a gain of 43.8 ° ISO is still obtained.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/737,684 US6019870A (en) | 1994-05-11 | 1995-04-14 | Process for the preparation of delignified and bleached chemical paper pulps |
EP95917403A EP0759105B2 (fr) | 1994-05-11 | 1995-04-14 | Procede de preparation de pates a papier chimiques delignifiees et blanchies |
CA002189796A CA2189796C (fr) | 1994-05-11 | 1995-04-14 | Procede de preparation de pates a papier chimiques delignifiees et blanchies |
AU23484/95A AU2348495A (en) | 1994-05-11 | 1995-04-14 | Method for preparing delignified and bleached chemical paper pulps |
NO19964609A NO320946B1 (no) | 1994-05-11 | 1996-10-31 | Fremgangsmate for fremstilling av avlignifisert og bleket kjemisk papirmasse |
FI964499A FI117394B (fi) | 1994-05-11 | 1996-11-08 | Menetelmä delignifioitujen ja valkaistujen kemiallisten paperimassojen valmistamiseksi |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR94/05815 | 1994-05-11 | ||
FR9405815A FR2719854B1 (fr) | 1994-05-11 | 1994-05-11 | Procédé de préparation de pâtes à papier chimiques délignifiées et blanchies. |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995031599A1 true WO1995031599A1 (fr) | 1995-11-23 |
Family
ID=9463129
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1995/000494 WO1995031599A1 (fr) | 1994-05-11 | 1995-04-14 | Procede de preparation de pates a papier chimiques delignifiees et blanchies |
Country Status (10)
Country | Link |
---|---|
US (1) | US6019870A (fr) |
EP (1) | EP0759105B2 (fr) |
CN (1) | CN1065304C (fr) |
AU (1) | AU2348495A (fr) |
CA (1) | CA2189796C (fr) |
ES (1) | ES2126278T5 (fr) |
FI (1) | FI117394B (fr) |
FR (1) | FR2719854B1 (fr) |
NO (1) | NO320946B1 (fr) |
WO (1) | WO1995031599A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0801169A1 (fr) * | 1996-04-12 | 1997-10-15 | Elf Atochem S.A. | Procédé de délignification et de blanchiment de pâtes à papier chimiques |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001200486A (ja) * | 1999-12-02 | 2001-07-27 | Andritz Ahlstrom Inc | 細砕セルロース繊維材のスラリーを処理する方法 |
US7001484B2 (en) | 2000-05-04 | 2006-02-21 | University Of New Brunswick | Peroxide bleaching of wood pulp using stabilizers and sodium hydrosulfide reducing agent |
AU2001256024A1 (en) * | 2000-05-04 | 2001-11-12 | University Of New Brunswick | Peroxide bleaching of wood pulp |
US20050087315A1 (en) * | 2003-10-28 | 2005-04-28 | Donovan Joseph R. | Low consistency oxygen delignification process |
CA2728278C (fr) | 2008-06-20 | 2016-06-28 | Zheng Tan | Composition et feuille d'impression presentant des proprietes optiques ameliorees |
CN102926254B (zh) * | 2012-11-18 | 2018-02-27 | 天津容业达科技发展有限公司 | 常压低温清洁制浆过程中添加的制浆助剂 |
US9365525B2 (en) | 2013-02-11 | 2016-06-14 | American Science And Technology Corporation | System and method for extraction of chemicals from lignocellulosic materials |
CN104088187A (zh) * | 2014-06-05 | 2014-10-08 | 华南理工大学 | 一种纸浆漂白方法 |
US9382283B2 (en) | 2014-08-01 | 2016-07-05 | American Science And Technology Corporation | Oxygen assisted organosolv process, system and method for delignification of lignocellulosic materials and lignin recovery |
US9950858B2 (en) | 2015-01-16 | 2018-04-24 | R.J. Reynolds Tobacco Company | Tobacco-derived cellulose material and products formed thereof |
US11154087B2 (en) | 2016-02-02 | 2021-10-26 | R.J. Reynolds Tobacco Company | Method for preparing flavorful compounds isolated from black liquor and products incorporating the flavorful compounds |
US10196778B2 (en) | 2017-03-20 | 2019-02-05 | R.J. Reynolds Tobacco Company | Tobacco-derived nanocellulose material |
CN110644270B (zh) * | 2019-08-27 | 2022-01-07 | 齐鲁工业大学 | 一种杨木kp浆tcf漂白生产溶解浆的工艺 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1979000861A1 (fr) * | 1978-03-31 | 1979-11-01 | Modo Chemetics Ab | Methode de raffinage de pulpe cellulosique |
EP0578304A1 (fr) * | 1992-07-06 | 1994-01-12 | SOLVAY INTEROX (Société Anonyme) | Procédé pour le blanchiment d'une pâte à papier chimique |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5658086A (en) * | 1979-10-17 | 1981-05-20 | Kogyo Gijutsuin | Multistage bleaching method of pulps |
DE3207157C1 (de) * | 1982-02-27 | 1983-06-09 | Degussa Ag, 6000 Frankfurt | Verfahren zur Herstellung von halbgebleichten Zellstoffen |
EP0402335B2 (fr) † | 1989-06-06 | 2001-03-14 | Eka Chemicals AB | Procédé de blanchiment de pâtes contenant de la lignocellulose |
ZA924351B (en) * | 1991-06-27 | 1993-03-31 | Ahlstroem Oy | Ozone bleaching process |
SE469842C (sv) * | 1992-01-21 | 1996-01-15 | Sunds Defibrator Ind Ab | Blekning av kemisk massa med peroxid |
-
1994
- 1994-05-11 FR FR9405815A patent/FR2719854B1/fr not_active Expired - Fee Related
-
1995
- 1995-04-14 ES ES95917403T patent/ES2126278T5/es not_active Expired - Lifetime
- 1995-04-14 AU AU23484/95A patent/AU2348495A/en not_active Abandoned
- 1995-04-14 WO PCT/FR1995/000494 patent/WO1995031599A1/fr active IP Right Grant
- 1995-04-14 CA CA002189796A patent/CA2189796C/fr not_active Expired - Fee Related
- 1995-04-14 CN CN95192987A patent/CN1065304C/zh not_active Expired - Fee Related
- 1995-04-14 US US08/737,684 patent/US6019870A/en not_active Expired - Fee Related
- 1995-04-14 EP EP95917403A patent/EP0759105B2/fr not_active Expired - Lifetime
-
1996
- 1996-10-31 NO NO19964609A patent/NO320946B1/no not_active IP Right Cessation
- 1996-11-08 FI FI964499A patent/FI117394B/fi not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1979000861A1 (fr) * | 1978-03-31 | 1979-11-01 | Modo Chemetics Ab | Methode de raffinage de pulpe cellulosique |
EP0578304A1 (fr) * | 1992-07-06 | 1994-01-12 | SOLVAY INTEROX (Société Anonyme) | Procédé pour le blanchiment d'une pâte à papier chimique |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0801169A1 (fr) * | 1996-04-12 | 1997-10-15 | Elf Atochem S.A. | Procédé de délignification et de blanchiment de pâtes à papier chimiques |
FR2747407A1 (fr) * | 1996-04-12 | 1997-10-17 | Atochem Elf Sa | Procede de delignification et de blanchiment de pates a papier chimiques |
CN1085756C (zh) * | 1996-04-12 | 2002-05-29 | 埃尔夫阿托化学有限公司 | 化学纸浆的脱木素和漂白的方法 |
US6554958B1 (en) | 1996-04-12 | 2003-04-29 | Atofina | Process for the delignification and bleaching of chemical paper pulps with hydrogen peroxide and at least one polymer |
Also Published As
Publication number | Publication date |
---|---|
NO964609L (no) | 1996-10-31 |
FI117394B (fi) | 2006-09-29 |
EP0759105B1 (fr) | 1998-12-02 |
NO320946B1 (no) | 2006-02-20 |
EP0759105B2 (fr) | 2001-10-10 |
ES2126278T5 (es) | 2002-02-16 |
AU2348495A (en) | 1995-12-05 |
FI964499A0 (fi) | 1996-11-08 |
CA2189796A1 (fr) | 1995-11-23 |
CN1147841A (zh) | 1997-04-16 |
FR2719854A1 (fr) | 1995-11-17 |
CN1065304C (zh) | 2001-05-02 |
US6019870A (en) | 2000-02-01 |
FI964499A (fi) | 1996-11-08 |
ES2126278T3 (es) | 1999-03-16 |
CA2189796C (fr) | 2000-08-22 |
NO964609D0 (no) | 1996-10-31 |
EP0759105A1 (fr) | 1997-02-26 |
FR2719854B1 (fr) | 1996-06-21 |
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