CA2157109C - Method of bleaching pulp with chlorine-free chemicals - Google Patents

Method of bleaching pulp with chlorine-free chemicals Download PDF

Info

Publication number: CA2157109C
Authority: CA; Canada
Prior art keywords: stage; pulp; recited; bleaching; ozone
Prior art date: 1993-03-03
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 - Fee Related

Application number

CA002157109A

Other languages

English (en)

French (fr)

Other versions

CA2157109A1 (en

Inventor

Kaj Henricson

Bertil Stromberg

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.)

Andritz Oy

Original Assignee

Andritz Oy

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.)

1993-03-03

Filing date

1993-05-25

Publication date

2002-09-03

Family has litigation

First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=8537491&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=CA2157109(C) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.

1993-05-25 Application filed by Andritz Oy filed Critical Andritz Oy

1994-09-15 Publication of CA2157109A1 publication Critical patent/CA2157109A1/en

2002-09-03 Application granted granted Critical

2002-09-03 Publication of CA2157109C publication Critical patent/CA2157109C/en

2013-05-25 Anticipated expiration legal-status Critical

Status Expired - Fee Related legal-status Critical Current

Links

238000004061 bleaching Methods 0.000 title claims abstract description 68
238000000034 method Methods 0.000 title claims description 44
239000000126 substance Substances 0.000 title claims description 24
CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 46
229910001385 heavy metal Inorganic materials 0.000 claims abstract description 28
150000002978 peroxides Chemical class 0.000 claims abstract description 24
QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 23
239000001301 oxygen Substances 0.000 claims abstract description 23
229910052760 oxygen Inorganic materials 0.000 claims abstract description 23
239000002655 kraft paper Substances 0.000 claims abstract description 9
239000000706 filtrate Substances 0.000 claims description 36
238000005406 washing Methods 0.000 claims description 34
238000012216 screening Methods 0.000 claims description 20
239000002253 acid Substances 0.000 claims description 19
239000003513 alkali Substances 0.000 claims description 15
239000011777 magnesium Substances 0.000 claims description 14
FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 12
229910052749 magnesium Inorganic materials 0.000 claims description 12
102000004190 Enzymes Human genes 0.000 claims description 7
108090000790 Enzymes Proteins 0.000 claims description 7
229910052751 metal Inorganic materials 0.000 claims description 7
239000002184 metal Substances 0.000 claims description 7
ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 6
239000000460 chlorine Substances 0.000 claims description 6
229910052801 chlorine Inorganic materials 0.000 claims description 6
238000000605 extraction Methods 0.000 claims description 6
150000002739 metals Chemical class 0.000 claims description 3
PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
229910052748 manganese Inorganic materials 0.000 claims description 2
239000011572 manganese Substances 0.000 claims description 2
239000002738 chelating agent Substances 0.000 claims 3
230000002378 acidificating effect Effects 0.000 claims 2
239000002657 fibrous material Substances 0.000 claims 2
238000007865 diluting Methods 0.000 claims 1
238000004519 manufacturing process Methods 0.000 abstract description 2
150000002894 organic compounds Chemical class 0.000 abstract 1
238000006243 chemical reaction Methods 0.000 description 12
230000008569 process Effects 0.000 description 8
238000004140 cleaning Methods 0.000 description 7
238000010411 cooking Methods 0.000 description 4
239000007789 gas Substances 0.000 description 4
KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 3
HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
239000000835 fiber Substances 0.000 description 3
229910052943 magnesium sulfate Inorganic materials 0.000 description 3
238000011084 recovery Methods 0.000 description 3
239000000725 suspension Substances 0.000 description 3
230000008719 thickening Effects 0.000 description 3
XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
239000012159 carrier gas Substances 0.000 description 2
238000005352 clarification Methods 0.000 description 2
150000001875 compounds Chemical class 0.000 description 2
230000003247 decreasing effect Effects 0.000 description 2
238000010790 dilution Methods 0.000 description 2
239000012895 dilution Substances 0.000 description 2
OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 2
238000002474 experimental method Methods 0.000 description 2
238000010438 heat treatment Methods 0.000 description 2
230000007935 neutral effect Effects 0.000 description 2
230000001590 oxidative effect Effects 0.000 description 2
239000002562 thickening agent Substances 0.000 description 2
235000018185 Betula X alpestris Nutrition 0.000 description 1
235000018212 Betula X uliginosa Nutrition 0.000 description 1
KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
239000004155 Chlorine dioxide Substances 0.000 description 1
230000004913 activation Effects 0.000 description 1
238000010420 art technique Methods 0.000 description 1
230000033228 biological regulation Effects 0.000 description 1
239000007844 bleaching agent Substances 0.000 description 1
239000007795 chemical reaction product Substances 0.000 description 1
235000019398 chlorine dioxide Nutrition 0.000 description 1
239000008139 complexing agent Substances 0.000 description 1
238000005260 corrosion Methods 0.000 description 1
230000007797 corrosion Effects 0.000 description 1
238000009826 distribution Methods 0.000 description 1
239000012467 final product Substances 0.000 description 1
239000013505 freshwater Substances 0.000 description 1
229920005610 lignin Polymers 0.000 description 1
235000019341 magnesium sulphate Nutrition 0.000 description 1
150000001455 metallic ions Chemical class 0.000 description 1
239000000203 mixture Substances 0.000 description 1
238000012986 modification Methods 0.000 description 1
230000004048 modification Effects 0.000 description 1
150000004045 organic chlorine compounds Chemical class 0.000 description 1
238000012545 processing Methods 0.000 description 1
239000000047 product Substances 0.000 description 1
230000001681 protective effect Effects 0.000 description 1
238000004076 pulp bleaching Methods 0.000 description 1
230000003134 recirculating effect Effects 0.000 description 1
238000011160 research Methods 0.000 description 1
239000011122 softwood Substances 0.000 description 1
238000012360 testing method Methods 0.000 description 1
229910021654 trace metal Inorganic materials 0.000 description 1
239000003643 water by type Substances 0.000 description 1

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
- D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating 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
- D21C9/1026—Other features in bleaching processes
- D21C9/1036—Use of compounds accelerating or improving the efficiency of the 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
- D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
- 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
- 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
- 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

Landscapes

Life Sciences & Earth Sciences (AREA)
Engineering & Computer Science (AREA)
Wood Science & Technology (AREA)
Paper (AREA)
Detergent Compositions (AREA)
Coloring Foods And Improving Nutritive Qualities (AREA)
Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

CA002157109A 1993-03-03 1993-05-25 Method of bleaching pulp with chlorine-free chemicals Expired - Fee Related CA2157109C (en)

Applications Claiming Priority (3)

Application Number	Priority Date	Filing Date	Title
FI930954		1993-03-03
FI930954A FI93232C (fi)	1993-03-03	1993-03-03	Menetelmä massan valkaisemiseksi kloorivapailla kemikaaleilla
PCT/FI1993/000222 WO1994020673A1 (en)	1993-03-03	1993-05-25	Method of bleaching pulp with chlorine-free chemicals

Publications (2)

Publication Number	Publication Date
CA2157109A1 CA2157109A1 (en)	1994-09-15
CA2157109C true CA2157109C (en)	2002-09-03

Family

ID=8537491

Family Applications (1)

Application Number	Title	Priority Date	Filing Date
CA002157109A Expired - Fee Related CA2157109C (en)	1993-03-03	1993-05-25	Method of bleaching pulp with chlorine-free chemicals

Country Status (13)

Country	Link
EP (2)	EP0687321B1 (de)
JP (1)	JP3276083B2 (de)
AT (2)	ATE228181T1 (de)
AU (1)	AU5370594A (de)
BR (1)	BR9307858A (de)
CA (1)	CA2157109C (de)
DE (2)	DE69323566T2 (de)
ES (2)	ES2130260T3 (de)
FI (3)	FI93232C (de)
NO (1)	NO953444L (de)
PT (1)	PT884415E (de)
RU (1)	RU2126471C1 (de)
WO (1)	WO1994020673A1 (de)

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number	Priority date	Publication date	Assignee	Title
FI89516B (fi)	1989-05-10	1993-06-30	Ahlstroem Oy	Foerfarande foer blekning av cellulosamassa med otson
FI103818B (fi) *	1995-02-21	1999-09-30	Ahlstrom Machinery Oy	Menetelmä massan valkaisemiseksi
US20080110584A1 (en) *	2006-11-15	2008-05-15	Caifang Yin	Bleaching process with at least one extraction stage
FR2910027B1 (fr) *	2006-12-13	2009-11-06	Itt Mfg Enterprises Inc	Procede de blanchiment des pates papeteries chimiques par traitement final a l'ozone a haute temperature
FI119062B (fi) *	2006-12-28	2008-07-15	Upm Kymmene Corp	Menetelmä mekaanisen massan valmistamiseksi
ES2752755T3 (es)	2009-05-28	2020-04-06	Gp Cellulose Gmbh	Celulosa modificada de fibra química kraft y métodos de producción y uso de la misma
AU2012268700B2 (en)	2011-05-23	2017-02-02	Gp Cellulose Gmbh	Softwood kraft fiber having improved whiteness and brightness and methods of making and using the same
MX366988B (es)	2012-01-12	2019-08-01	Gp Cellulose Gmbh	Fibra kraft de baja viscosidad que tiene propiedades de amarillez reducida, y metodos para prepararla y usarla.
EP3495550A1 (de)	2012-04-18	2019-06-12	GP Cellulose GmbH	Verwendung eines tensids zur behandlung von pulpe und zur verbesserung der aufnahme von kraft-pulpe in fasern zur herstellung von viskose und anderen sekundären faserprodukten
MX365675B (es)	2013-02-08	2019-06-10	Gp Cellulose Gmbh	Fibra kraft de madera blanda que tiene un contenido mejorado de a-celulosa, y su uso en la produccion de productos de celulosa quimica.
EP2971334A2 (de)	2013-03-14	2016-01-20	GP Cellulose GmbH	Verfahren zur herstellung hochfunktioneller, niedrigviskoser kraftfasern mittels eines sauren bleichsequenz und nach diesem verfahren hergestellte faser
CA2901915A1 (en)	2013-03-15	2014-09-18	Gp Cellulose Gmbh	A low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
FR3007044B1 (fr) *	2013-06-13	2016-01-15	Air Liquide	Procede de traitement des pates papetieres chimiques par traitement a l'ozone en presence d'ions magnesium
AT515152B1 (de) *	2013-11-26	2015-12-15	Chemiefaser Lenzing Ag	Verfahren zum Vorbehandeln von rückgewonnenen Baumwollfasern zur Verwendung bei der Herstellung von Formkörpern aus regenerierter Cellulose
WO2018093697A1 (en)	2016-11-16	2018-05-24	Gp Cellulose Gmbh	Modified cellulose from chemical fiber and methods of making and using the same
SE544236C2 (en) *	2020-12-21	2022-03-08	Valmet Oy	Method for bleaching pulp from recycled textile material
SE545759C2 (en) *	2022-06-20	2024-01-02	Valmet Oy	Method for bleaching pulp from recycled textile material

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number	Priority date	Publication date	Assignee	Title
NO144711C (no) *	1978-04-04	1981-10-21	Myrens Verksted As	Fremgangsmaate til bleking av oksygendelignifiserte celluloseholdige masser med ozon
US4310384A (en) *	1979-01-11	1982-01-12	Weyerhaeuser Company	Reducing chemical transfer between treatment stages
FI74752C (fi) *	1986-03-20	1992-12-01	Ahlstroem Oy	Foerfarande och anordning foer tvaettning av cellulosa
DE69004492T3 (de) *	1989-06-06	2001-11-15	Eka Nobel Ab, Bohus	Verfahren zum Bleichen von Lignocellulose enthaltenden Zellstoffen.
SU1675451A1 (ru) *	1989-09-25	1991-09-07	Центральный научно-исследовательский институт бумаги	Способ подготовки волокнистого полуфабриката к отливу бумажного полотна при изготовлении бумаги
AU636173B2 (en) *	1989-10-30	1993-04-22	Lenzing Aktiengesellschaft	Method for the chlorine-free bleaching of pulps
US5567262A (en) *	1991-04-16	1996-10-22	Ahlstrom Machinery Inc.	Two stage pressure diffuser
SE468355B (sv) *	1991-04-30	1992-12-21	Eka Nobel Ab	Blekning av kemisk massa genom behandling med komplexbildare och ozon
AT400153B (de) *	1991-05-02	1995-10-25	Voest Alpine Ind Anlagen	Verfahren zum bleichen von xylan- und lignocellulosehältigen materialien

1993
- 1993-03-03 FI FI930954A patent/FI93232C/fi active
- 1993-05-25 AT AT98113684T patent/ATE228181T1/de not_active IP Right Cessation
- 1993-05-25 BR BR9307858A patent/BR9307858A/pt not_active IP Right Cessation
- 1993-05-25 DE DE69323566T patent/DE69323566T2/de not_active Expired - Fee Related
- 1993-05-25 ES ES93910051T patent/ES2130260T3/es not_active Expired - Lifetime
- 1993-05-25 PT PT98113684T patent/PT884415E/pt unknown
- 1993-05-25 EP EP93910051A patent/EP0687321B1/de not_active Expired - Lifetime
- 1993-05-25 ES ES98113684T patent/ES2186948T3/es not_active Expired - Lifetime
- 1993-05-25 FI FI954093A patent/FI954093A7/fi not_active IP Right Cessation
- 1993-05-25 DE DE69332508T patent/DE69332508T2/de not_active Expired - Fee Related
- 1993-05-25 AT AT93910051T patent/ATE176808T1/de not_active IP Right Cessation
- 1993-05-25 CA CA002157109A patent/CA2157109C/en not_active Expired - Fee Related
- 1993-05-25 JP JP51962394A patent/JP3276083B2/ja not_active Expired - Fee Related
- 1993-05-25 WO PCT/FI1993/000222 patent/WO1994020673A1/en not_active Ceased
- 1993-05-25 RU RU95122814A patent/RU2126471C1/ru active
- 1993-05-25 AU AU53705/94A patent/AU5370594A/en not_active Abandoned
- 1993-05-25 EP EP98113684A patent/EP0884415B1/de not_active Expired - Lifetime
- 1993-09-15 FI FI934036A patent/FI98223B/fi not_active IP Right Cessation
1995
- 1995-09-01 NO NO953444A patent/NO953444L/no unknown

Also Published As

Publication number	Publication date
DE69323566T2 (de)	1999-07-15
WO1994020673A1 (en)	1994-09-15
PT884415E (pt)	2003-03-31
RU2126471C1 (ru)	1999-02-20
JP3276083B2 (ja)	2002-04-22
EP0884415A1 (de)	1998-12-16
FI98223B (fi)	1997-01-31
EP0884415B1 (de)	2002-11-20
FI954093A0 (fi)	1995-08-30
JPH08509781A (ja)	1996-10-15
FI930954A0 (fi)	1993-03-03
FI93232B (fi)	1994-11-30
ES2130260T3 (es)	1999-07-01
FI934036A0 (fi)	1993-09-15
DE69332508D1 (de)	2003-01-02
ES2186948T3 (es)	2003-05-16
FI954093A7 (fi)	1995-10-17
ATE228181T1 (de)	2002-12-15
AU5370594A (en)	1994-09-26
EP0687321B1 (de)	1999-02-17
NO953444L (no)	1995-10-19
EP0687321A1 (de)	1995-12-20
BR9307858A (pt)	1996-02-27
DE69332508T2 (de)	2003-07-03
ATE176808T1 (de)	1999-03-15
FI93232C (fi)	1995-03-10
NO953444D0 (no)	1995-09-01
CA2157109A1 (en)	1994-09-15
FI930954L (fi)	1994-09-04
DE69323566D1 (de)	1999-03-25
FI934036L (fi)	1994-09-04

Legal Events

Date	Code	Title	Description
1995-08-28	EEER	Examination request
2005-05-25	MKLA	Lapsed

Publication	Publication Date	Title
US6010594A (en)	2000-01-04	Method of bleaching pulp with chlorine-free chemicals wherein a complexing agent is added immediately after an ozone bleach stage
EP0687321B1 (de)	1999-02-17	Verfahren zum bleichen von zellstoff mit chlorfreien chemikalien
CA2235325C (en)	2006-02-14	Acid treatment of pulp at high temperature in connection with bleaching
AU670659B2 (en)	1996-07-25	Process for delignification of lignocellulose-containing pulp
CA2111519C (en)	2001-07-31	Oxygen/ozone/peracetic acid delignification and bleaching of cellulosic pulps
EP0857231B1 (de)	2003-11-19	Sauerstoffdelignifizierung von lignocelluloschischem zellstoff in zwei stufen
RU95122814A (ru)	1997-09-20	Способ производства целлюлозы без применения хлорных химикатов
CA2031848C (en)	1995-11-21	Method of bleaching pulp
US6605181B1 (en)	2003-08-12	Peroxide bleach sequence including an acidic bleach stage and including a wash stage
WO1996009434A1 (en)	1996-03-28	Method of bleaching kraft pulp
AU665461B2 (en)	1996-01-04	Method of treating process water
CA2031850C (en)	1995-11-21	Method of bleaching pulp
EP1061173A1 (de)	2000-12-20	Delignifizierung von lignocellulosischem Material mittels Sauerstoff
CA2163116C (en)	2003-12-30	Method of bleaching pulp without using chlorine chemicals
US20020056533A1 (en)	2002-05-16	Method of treating chemical cellulose pulp
WO1995008021A1 (en)	1995-03-23	Eop stage for chlorine free bleaching
US20070295462A1 (en)	2007-12-27	Method For Treating Pulp In Connection With The Bleachine Of Chemical Pulp
US6375797B1 (en)	2002-04-23	Bleaching chemical pulp in a PkDQ-Po Sequence
WO1998014657A1 (en)	1998-04-09	Oxidation of disturbing metal ions in bleaching processes
AU7875491A (en)	1992-11-17	Pulp alkali addition process for high consistency oxygen delignification
WO2007108760A1 (en)	2007-09-27	Final bleaching of cellulose pulp with ozone
CA2179700A1 (en)	1996-12-22	Method and apparatus for treating pulp