EP0191756B1 - Mehrstufige Peroxidbleiche einer mechanischen Pulpe - Google Patents

Mehrstufige Peroxidbleiche einer mechanischen Pulpe Download PDF

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Publication number
EP0191756B1
EP0191756B1 EP86890030A EP86890030A EP0191756B1 EP 0191756 B1 EP0191756 B1 EP 0191756B1 EP 86890030 A EP86890030 A EP 86890030A EP 86890030 A EP86890030 A EP 86890030A EP 0191756 B1 EP0191756 B1 EP 0191756B1
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EP
European Patent Office
Prior art keywords
pulp
bleaching
peroxide
mechanical
stage
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
Application number
EP86890030A
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English (en)
French (fr)
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EP0191756A1 (de
Inventor
Petter Tibbling
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.)
Metso Fiber Karlstad AB
Original Assignee
Kamyr AB
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Filing date
Publication date
Application filed by Kamyr AB filed Critical Kamyr AB
Priority to AT86890030T priority Critical patent/ATE39714T1/de
Publication of EP0191756A1 publication Critical patent/EP0191756A1/de
Application granted granted Critical
Publication of EP0191756B1 publication Critical patent/EP0191756B1/de
Expired legal-status Critical Current

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    • 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

Definitions

  • the invention relates to a method of obtaining high brightness lignocellulose pulp comprising the steps of subjecting a mechanical lignocellulose . pulp to peroxide bleaching and a hydrosulfite bleaching sequence, and to a high brightness mechanical lignocellulose pulp.
  • Typical conventional bleaching sequences for the bleaching of mechanical pulps such as mechanical pulp, chemimechanical pulp (CMP), thermomechanical pulp (TMP) and chemither- momechanical pulp (CTMP) comprise peroxide (P), hydrosulfite (T), or P-T sequences.
  • Reductive bleaching with hydrosulfites is also commonly practiced in a single stage.
  • a P-T bleaching sequence which gives brightness in the range of about 74-78% ISO.
  • the contribution to brightness of the final T stage is gradually reduced as the charge of peroxide is increased in order to boost final brightness.
  • the invention as claimed is intended to further improve the result of treatment without adding further steps to the process.
  • the T stage does produce a substantial brightening effect, on the order of 2-4 ISO units.
  • the contribution from the hydrosulfite stage is very small (less than 2 ISO units) at the 80 + ISO level.
  • the method is characterized by subjecting the mechanical pulp to a first peroxide bleaching, and then to a second peroxide bleaching, and then to the hydrosulfite bleaching sequence, to produce a bleached mechanical pulp. More than two peroxide stages may be provided, and the sequence of steps preferably practiced sequentially. Preferably the pulp is pressed between the stages to partially remove interstitial pulp liquor. This removed liquor (filtrate) is normally reused for dilution in preceding stages, orforchemical recovery. During the practice of all of steps the pulp maintains a consistency of between 8-50%, although after pressing it is typically diluted (e.g. to between 8-15%). During each actual bleaching stage the consistency is between 8-30%.
  • the invention also relates to a mechanical pulp having high brightness, and produced by the practice of the aforementioned sequence of steps. According to the invention, a mechanical pulp is produced having a brightness of 83% ISO (or greater).
  • a mechanical lignocellulose pulp as used in the specification and claims is intended to encompass conventional mechanical pulps, such as ground wood and refiner pulps, e.g. CMP, CTMP, and TMP.
  • Figure 1 illustrates the production of a mechanical pulp in a typical mechanical pulping process station 10, which includes the use of refiners, and other pulping process stages as desired.
  • a mechanical lignocellulose pulp is produced in station 10, it is subjected to a first sodium or hydrogen peroxide bleaching P 1 , as indicated by reference numeral 12 in Figure 1.
  • Peroxide bleaching is accomplished utilizing conventional equipment, and conventional bleaching conditions for peroxide bleaching of mechanical pulps (e.g.. 45-90°C, 15-240 minutes).
  • a typical form such equipment can take is illustrated schematically in Figure 3 wherein the pulp is fed to a mixer 14, the peroxide, sodium hydroxide, and buffering and stabilizing agents or the like (such as sodium silicate and MgS0 4 ) are added.
  • the consistency of the pulp may be increased in screw press 15, and ultimately the pulp is fed to bleaching tower 16.
  • Bleaching would typically be accomplished at a consistency of about 8-30%, preferably about 12-25%.
  • the pulp is passed to the second peroxide stage P 2 , indicated by reference numeral 18 in Figure 1. There it is subjected to another typical peroxide bleaching sequence.
  • Other peroxide bleaching sequences after stage 12 e.g. P 3 , P 4 , etc. may be provided.
  • press station 19 is disposed between the peroxide bleaching sequence stages 12, 18.
  • the pulp is pressed to a high consistency (e.g. on the order of 30-50%) before the bleach liquid for the subsequent peroxide stage 18 is added.
  • pressing in press station 19' preferably is practiced after stage 18.
  • the pulp is subjected to a hydrosulfite bleaching, as illustrated schematically by reference numeral 20 in Figure 1.
  • the conditions in the hydrosulfite bleaching stage 20 are conventional (e.g. 45-90°C, 10-60 min.) except that it is preferred that the bleaching be practiced with a pulp consistency of between about 8-30%, preferably between about 8-15%.
  • Hydrosulfite bleaching of medium consistency mechanical pulps is illustrated in EP-A- * 0,155,928, and the equipment and processes illustrated therein may be utilized in the practice of bleaching 20.
  • FIG. 4 schematically illustrates one form of the typical equipment that could be utilized in the practice of stage 20, wherein the pulp, after having been pressed and diluted to about 8-15% consistency, is mixed with hydrosulfite and other chemicals, such as buffering, chelating, and sequestering agents.
  • the pulp is fluidized by the mixer 22, and then passes to conventional upflow tower 24.
  • the bleached mechanical pulp produced according to the sequence illustrated in Figure 1 has high brightness; brightness on the order of about 83% ISO units, or more, can be achieved. Almost as high a brightness can be achieved if a peroxide stage is utilized both before and after a hydrosulfite stage. This is shown schematically in Figure 5 wherein T stage 20' is between P 1 stage 12' and P 2 stage 18'.
  • T stage 20' is between P 1 stage 12' and P 2 stage 18'.
  • a P-T sequence was practiced on unbleached CTMP pulp having 53.5% ISO, 160/110 (cold/hot) ml C.S.F. (millimeters, Canadian Standard Free- ness) containing 0.4% DCM-extract (a measure of the amount of resin), 92 ppm manganese, and 9 ppm iron.
  • the pulp was pretreated with 0.2% DTPA (pentasodium salt of diethylenetriamine pentaacetic acid on bone dry (BD) pulp at 3% consistency and 60°C. The temperature in both the P and T stages was 80°C, and the pulp consistency was 15% in both stages.
  • DTPA dipentasodium salt of diethylenetriamine pentaacetic acid on bone dry (BD) pulp
  • the treatment time in the peroxide stage was 180 minutes using 3% sodium silicate and 0.2% MgS0 4 for buffering and stabilizing the peroxide liquid.
  • the reaction time was 30 minutes, using 1% hydrosulfite which was all consumed. The following results were obtained:
  • the pulp was pressed and the pH was reduced by the addition of S0 2 water, the reduction practiced so that the pH was about 5.5-6.0 just prior to the hydrosulfite stage, and the pulp was diluted as necessary in order to maintain the consistency throughout the actual bleaching stages at about 15%.
  • the hydrosulfite stage was between two peroxide stages (see Fig. 5).
  • the pulp, and general conditions, were the same as for Example 2, with the following results:
  • the final pulp brightness of almost 83 ISO (82.6) was suprisingly high, although not quite as high as.the one for the sequence in Example 2.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Joints Allowing Movement (AREA)
  • Springs (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Electron Beam Exposure (AREA)
  • Liquid Crystal Substances (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Claims (9)

1. Verfahren zum Erhalten einer Lignozellulosepulpe von hohem Weißgrad, wobei eine mechanische Lignozellulosepulpe einem Peroxidbleichvorgang und einem Hydrosulfitbleichvorgang (20) unterworfen wird, dadurch gekennzeichnet, daß die mechanische Pulpe einem ersten Peroxidbleichvorgang (21), darauf einem zweiten Peroxidbleichvorgang (18) und danach dem Hydrosulfitbleichvorgang (20) unterworfen wird, um eine gebleichte mechanische Pulpe herzustellen.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Konsistenz der Pulpe während der Ausführung eines jeden der Schritte im Bereich von 8-30% liegt.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß die Konsistenz der Pulpe während des Hydrosulfitbleichvorganges im Bereich von 8-15% liegt.
4. Verfahren nach Anspruch 3, mit dem weiteren Schritt, daß vor dem Hydrosulfitbleichvorgang der pH-Wert der mechanischen Pulpe auf 5,5-6,0 herabgesetzt wird (26).
5. Verfahren nach Anspruch 1, bei welchem in einem weiteren Schritt zwischen den Peroxidbleichschritten die mechanische Pulpe gepreßt wird (19).
6. Verfahren nach Anspruch 1, bei welchem der erste und der zweite Peroxidbleichschritt und der Hydrosulfitbleichvorgang die einzigen zur Behandlung der mechanischen Pulpe ausgeübten Bleichschritte sind.
7. Mechanische Lignozellulosepulpe von hohem Weißgrad, dadurch gekennzeichnet, daß sie durch die nachstehend angeführten aufeinanderfolgenden Schritte hergestellt ist: (a) eine mechanische Lignozellulosepulpe wird einem ersten Peroxidbleichvorgang (12) unterworfen; dann (b) wird die mechanische Pulpe einem zweiten Peroxidbleichvorgang (18) unterworfen; und danach (c) wird die mechanische Pulpe einem Hydrosulfitbleichvorgang (20) unterworfen.
8. Pulpe von hohem Weißgrad nach Anspruch 7, dadurch gekennzeichnet, daß sie einen Weißgrad von 83% ISO hat.
EP86890030A 1985-02-15 1986-02-12 Mehrstufige Peroxidbleiche einer mechanischen Pulpe Expired EP0191756B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86890030T ATE39714T1 (de) 1985-02-15 1986-02-12 Mehrstufige peroxidbleiche einer mechanischen pulpe.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US70200085A 1985-02-15 1985-02-15
US702000 1985-02-15

Publications (2)

Publication Number Publication Date
EP0191756A1 EP0191756A1 (de) 1986-08-20
EP0191756B1 true EP0191756B1 (de) 1989-01-04

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ID=24819495

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86890030A Expired EP0191756B1 (de) 1985-02-15 1986-02-12 Mehrstufige Peroxidbleiche einer mechanischen Pulpe

Country Status (8)

Country Link
EP (1) EP0191756B1 (de)
JP (1) JPS61245392A (de)
AT (1) ATE39714T1 (de)
BR (1) BR8600637A (de)
DE (1) DE3661641D1 (de)
FI (1) FI85729C (de)
NO (1) NO166244C (de)
SE (1) SE8600615L (de)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE455203B (sv) * 1986-10-20 1988-06-27 Eka Nobel Ab Forfarande for styrning av peroxidblekning av massa
FR2622221A1 (fr) * 1987-10-22 1989-04-28 Atochem Procede de blanchiment de pates
FR2639371B1 (fr) * 1988-11-24 1995-04-14 Atochem Procede de blanchiment de pates desencrees
CA1340348C (en) * 1989-03-23 1999-01-26 Michel Barbe Bleaching process for the production of high bright pulps
JPH076148B2 (ja) * 1989-06-27 1995-01-30 新王子製紙株式会社 リグノセルロース物質の漂白方法
BE1004630A3 (fr) * 1990-10-17 1992-12-22 Interox Internat Sa Procede pour la preservation des caracteristiques de resistance mecanique des pates a papier chimiques.
GB9212926D0 (en) * 1992-06-18 1992-07-29 Morton Int Inc Method of bleaching paper pulp
US5464501A (en) * 1993-04-06 1995-11-07 Societe Anonyme Pour L'etude Et L'exploitation L'air Liquide, Des Procedes Georges Claude Bleaching recycled pulp with a reductive-oxidative sequence
IT1296947B1 (it) * 1997-12-10 1999-08-03 Donato Fausto De Composizione per sbiancare la pasta di legno e relativo procedimento
EP1418269B1 (de) * 2002-11-05 2009-02-11 Rohm And Haas Company Verfahren zum Bleichen von mechanischer Pulpe

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0187477A1 (de) * 1984-12-21 1986-07-16 Pulp and Paper Research Institute of Canada Mehrstufige Aufhellung von Holzpulpen die mit hoher und ultrahoher Ausbeute gewonnen sind

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1820502A (en) * 1928-06-30 1931-08-25 Champion Fibre Company Bleaching cellulose pulp
US2290601A (en) * 1940-02-16 1942-07-21 Du Pont Bleaching of ground wood pulp with preliminary bisulphite treatment
US2862784A (en) * 1955-03-04 1958-12-02 Virginia Smelting Company Oxidative-reductive multi-stage bleaching of ground wood pulp
JPS5679798A (en) * 1979-12-03 1981-06-30 Mitsubishi Gas Chemical Co Production of bleaching machine pulp
JPS575992A (en) * 1980-06-04 1982-01-12 Mitsubishi Gas Chemical Co Bleaching of high yield pulp by peroxide

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0187477A1 (de) * 1984-12-21 1986-07-16 Pulp and Paper Research Institute of Canada Mehrstufige Aufhellung von Holzpulpen die mit hoher und ultrahoher Ausbeute gewonnen sind

Also Published As

Publication number Publication date
SE8600615L (sv) 1986-08-16
NO166244B (no) 1991-03-11
EP0191756A1 (de) 1986-08-20
BR8600637A (pt) 1986-11-04
FI860688A0 (fi) 1986-02-14
DE3661641D1 (en) 1989-02-09
JPS61245392A (ja) 1986-10-31
SE8600615D0 (sv) 1986-02-12
FI85729C (fi) 1992-05-25
FI85729B (fi) 1992-02-14
NO166244C (no) 1991-06-19
FI860688A (fi) 1986-08-16
ATE39714T1 (de) 1989-01-15
NO860546L (no) 1986-08-18

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