EP0442425B1 - Verfahren zur chlorfreien Bleiche und Delignifizierung von Zellstoff - Google Patents

Verfahren zur chlorfreien Bleiche und Delignifizierung von Zellstoff Download PDF

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Publication number
EP0442425B1
EP0442425B1 EP91101890A EP91101890A EP0442425B1 EP 0442425 B1 EP0442425 B1 EP 0442425B1 EP 91101890 A EP91101890 A EP 91101890A EP 91101890 A EP91101890 A EP 91101890A EP 0442425 B1 EP0442425 B1 EP 0442425B1
Authority
EP
European Patent Office
Prior art keywords
cyanamide
peroxide
treatment
pulp
cellulose
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
EP91101890A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0442425A1 (de
Inventor
Werner Dr. Sturm
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.)
Evonik Operations GmbH
Original Assignee
SKW Trostberg AG
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 SKW Trostberg AG filed Critical SKW Trostberg AG
Priority to AT91101890T priority Critical patent/ATE103649T1/de
Publication of EP0442425A1 publication Critical patent/EP0442425A1/de
Application granted granted Critical
Publication of EP0442425B1 publication Critical patent/EP0442425B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • D21C9/147—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
    • D21C9/1026—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
    • D21C9/147—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

Definitions

  • the present invention relates to a process for chlorine-free bleaching and delignification of cellulose which has already been pre-bleached with oxygen and peroxide or oxygen and ozone.
  • Lignin-free cellulose is largely required to produce white-stable and / or high-strength paper products.
  • the pulp which is made from vegetable raw materials such as wood, reeds, straw, bagasse or similar. is obtained by chemical digestion (sulfate or sulfite digestion), subjected to a delignifying bleach.
  • the present invention is therefore based on the object of developing a process for chlorine-free bleaching and delignification of pulp pre-bleached with oxygen and peroxide or oxygen and ozone, which does not have the disadvantages of the prior art mentioned, but rather with little technical effort and without assistance of chlorine-containing treatment agents enables the production of pulps with high whiteness.
  • This object has been achieved according to the invention by subjecting the pre-bleached pulp to a double treatment with peroxide which has been activated with cyanamide and / or cyanamide salts.
  • pre-bleached pulp is used as the starting material, which has been pretreated with oxygen and peroxide or oxygen and ozone by a customary extraction step and has quite different degrees of whiteness depending on the type of pulp.
  • pre-bleached spruce pulps have whiteness levels of 65% to 75%, the corresponding whiteness levels of beech pulp are already over 80% in some cases.
  • the kappa values for the degree of delignification are normally between 2 and 10, in particular between 3 and 8.
  • the two treatment stages according to the invention include the bleaching and delignification of peroxide with cyanamide or cyanamide salts, which are preferably in the form of the alkaline salts such as e.g. Sodium hydrogen cyanamide, calcium cyanamide or magnesium cyanamide can be used.
  • cyanamide or cyanamide salts which are preferably in the form of the alkaline salts such as e.g. Sodium hydrogen cyanamide, calcium cyanamide or magnesium cyanamide can be used.
  • the amounts of peroxide and cyanamide derivatives differ only slightly in the two treatment stages. All water-soluble bleach-active peroxy compounds can be used as the peroxide. Hydrogen peroxide or sodium peroxide are preferred.
  • the second stage is preferably carried out at a cyanamide content of 0.01 to 0.7% by weight, in particular 0.03 to 0.23% by weight, in each case based on the dry weight of the pulp.
  • the peroxide content can preferably be varied between 0.1 and 3.0% by weight during the first treatment stage and between 0.1 and 2.0% by weight based on the dry weight of the pulp during the second treatment stage.
  • the pH is made alkaline and can generally be from 9 to 12.
  • the pH is adjusted with the known alkaline substances, sodium hydroxide being preferred for reasons of better solubility. Normally, 0.3 to 1.5% by weight of sodium hydroxide, based on the dry weight of the pulp, is sufficient to set the desired pH.
  • the solid densities can be varied within wide limits in both treatment stages, solid densities of 5 to 30% by weight, in particular those of 7 to 20% by weight, being particularly preferred.
  • the treatment stages according to the invention are preferably carried out at temperatures from 30 ° to 95 ° C., particularly preferably from 55 ° to 80 ° C., wherein treatment times of 1 to 8 hours are usually required in order to achieve the desired degree of whiteness to reach.
  • the addition of cyanamide and / or cyanamide salts generally makes it possible to shorten the reaction time and / or to lower the temperature compared to peroxide treatment without this activator, if this is desired for any reason.
  • three-quarter or fully bleached cellulose can be produced in a technically simple manner and without the aid of chlorine-containing chemicals, which have whiteness levels of> 80%.
  • Beech magnesium bisulfite pulp was further treated after an EOP pretreatment with 82.6% whiteness analogously to Example 1 under the following conditions:

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Cereal-Derived Products (AREA)
  • Gyroscopes (AREA)
  • Eye Examination Apparatus (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
EP91101890A 1990-02-13 1991-02-11 Verfahren zur chlorfreien Bleiche und Delignifizierung von Zellstoff Expired - Lifetime EP0442425B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT91101890T ATE103649T1 (de) 1990-02-13 1991-02-11 Verfahren zur chlorfreien bleiche und delignifizierung von zellstoff.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4004364 1990-02-13
DE4004364A DE4004364A1 (de) 1990-02-13 1990-02-13 Verfahren zur chlorfreien bleiche und delignifizierung von zellstoff

Publications (2)

Publication Number Publication Date
EP0442425A1 EP0442425A1 (de) 1991-08-21
EP0442425B1 true EP0442425B1 (de) 1994-03-30

Family

ID=6400030

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91101890A Expired - Lifetime EP0442425B1 (de) 1990-02-13 1991-02-11 Verfahren zur chlorfreien Bleiche und Delignifizierung von Zellstoff

Country Status (7)

Country Link
EP (1) EP0442425B1 (enrdf_load_stackoverflow)
AT (1) ATE103649T1 (enrdf_load_stackoverflow)
CA (1) CA2036173C (enrdf_load_stackoverflow)
DE (2) DE4004364A1 (enrdf_load_stackoverflow)
ES (1) ES2051531T3 (enrdf_load_stackoverflow)
FI (1) FI910703A7 (enrdf_load_stackoverflow)
NO (1) NO176329C (enrdf_load_stackoverflow)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4031597A1 (de) * 1990-10-05 1992-04-09 Sueddeutsche Kalkstickstoff Verfahren zur chlorarmen bleiche und delignifizierung von zellstoff
BR9205490A (pt) * 1991-01-03 1994-04-05 Union Camp Patent Holding Processos para a fabricacao de pasta branqueada tendo um britho GE final de pelo menos cerca de 75 e para a deslignificacao e branqueamento de uma pasta lignocelulosica
DE4138006A1 (de) * 1991-11-19 1993-05-27 Degussa Verfahren zur verbesserung des weissgehaltes bei der peroxidbleiche von zellstoffen durch den zusatz von cyanaten
US5620563A (en) * 1994-10-31 1997-04-15 Pulp Paper Res Inst Process for delignification and bleaching of chemical wood pulps with hydrogen peroxide and a dicyandiamide activator

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0325731A1 (de) * 1988-01-28 1989-08-02 Degussa Aktiengesellschaft Verfahren zur Herstellung von halbgebleichtem Kraftzellstoff

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4196043A (en) * 1970-12-21 1980-04-01 Scott Paper Company Kraft pulp bleaching and recovery process
DE3544398A1 (de) * 1985-12-16 1987-06-19 Sueddeutsche Kalkstickstoff Verfahren zur bleiche und delignifizierung von zellstoffhaltigen produkten
DE3714107A1 (de) * 1987-04-28 1988-11-10 Sueddeutsche Kalkstickstoff Verfahren zur entfernung von rest-wasserstoffperoxid aus waessrigen loesungen

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0325731A1 (de) * 1988-01-28 1989-08-02 Degussa Aktiengesellschaft Verfahren zur Herstellung von halbgebleichtem Kraftzellstoff

Also Published As

Publication number Publication date
EP0442425A1 (de) 1991-08-21
NO176329B (no) 1994-12-05
ATE103649T1 (de) 1994-04-15
CA2036173C (en) 1996-01-23
NO910458D0 (no) 1991-02-06
DE4004364C2 (enrdf_load_stackoverflow) 1992-11-19
DE4004364A1 (de) 1991-08-14
NO910458L (no) 1991-08-14
NO176329C (no) 1995-03-15
FI910703L (fi) 1991-08-14
DE59101249D1 (de) 1994-05-05
ES2051531T3 (es) 1994-06-16
CA2036173A1 (en) 1991-08-14
FI910703A0 (fi) 1991-02-13
FI910703A7 (fi) 1991-08-14

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