SE9403756D0 - Chlorine-free bleaching with short bleaching sequence and recirculation of filtrate - Google Patents

Chlorine-free bleaching with short bleaching sequence and recirculation of filtrate

Info

Publication number
SE9403756D0
SE9403756D0 SE9403756A SE9403756A SE9403756D0 SE 9403756 D0 SE9403756 D0 SE 9403756D0 SE 9403756 A SE9403756 A SE 9403756A SE 9403756 A SE9403756 A SE 9403756A SE 9403756 D0 SE9403756 D0 SE 9403756D0
Authority
SE
Sweden
Prior art keywords
stage
pulp
filtrate
bleaching
washing
Prior art date
Application number
SE9403756A
Other languages
Swedish (sv)
Other versions
SE9403756L (en
SE516814C2 (en
Inventor
Kaj Henricson
Olavi Pikka
Bertil Stromberg
Original Assignee
Ahlstroem 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.)
Filing date
Publication date
Application filed by Ahlstroem Oy filed Critical Ahlstroem Oy
Publication of SE9403756D0 publication Critical patent/SE9403756D0/en
Publication of SE9403756L publication Critical patent/SE9403756L/en
Publication of SE516814C2 publication Critical patent/SE516814C2/en

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
    • D21C9/147—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
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/0021—Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle)
    • D21C11/0028—Effluents derived from the washing or bleaching plants
    • 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
    • D21C9/1042—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

Landscapes

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

Abstract

A method of total chlorine-free bleaching to a brightness of ISO 82-90 uses an acid stage and a superatmospheric pressure peroxide stage. The acid stage (which may be the only acid stage) may comprise a Q stage or a Z (ozone) stage, in which metals in the pulp are freed from pulp fibers and become dissolved in the surrounding liquid. The pulp is then subjected to fractional washing to produce at least two wash filtrates, the first filtrate having over 50% of the dissolved metals from the pulp. The first filtrate is ultimately returned (e.g. through brown stock washing) to the black liquor recovery system of the pulp mill so that the metals precipitate on organics in the black liquor recovery system due to the alkaline pH of the black liquor. Other filtrates from the fractional washing are used to wash the pulp just before the acidic (e.g. ozone) stage. Acid and/or a chelating agent are added tothe wash liquid during fractional washing so that the pH of the first filtrate is six or less, and magnesium may be added to the pulp while it has an acidic pH just prior to the peroxide bleaching stage. From the fractional washing stage the filtrates may each have a flow volume of 0.5-7 cubic meters per ton of pulp. A further (ZP) stage may be added if it is desired to achieve a brightness of ISO 89 or above.
SE9403756A 1993-11-03 1994-11-02 Chlorine-free bleaching with short bleaching sequence and recirculation of filtrate SE516814C2 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US14486993A 1993-11-03 1993-11-03

Publications (3)

Publication Number Publication Date
SE9403756D0 true SE9403756D0 (en) 1994-11-02
SE9403756L SE9403756L (en) 1995-05-04
SE516814C2 SE516814C2 (en) 2002-03-05

Family

ID=22510496

Family Applications (2)

Application Number Title Priority Date Filing Date
SE9403756A SE516814C2 (en) 1993-11-03 1994-11-02 Chlorine-free bleaching with short bleaching sequence and recirculation of filtrate
SE0103975A SE0103975L (en) 1993-11-03 2001-12-10 Chlorine-free bleaching with short bleaching sequence and recirculation of filtrate

Family Applications After (1)

Application Number Title Priority Date Filing Date
SE0103975A SE0103975L (en) 1993-11-03 2001-12-10 Chlorine-free bleaching with short bleaching sequence and recirculation of filtrate

Country Status (3)

Country Link
CA (1) CA2134730C (en)
FI (1) FI945139A (en)
SE (2) SE516814C2 (en)

Also Published As

Publication number Publication date
SE9403756L (en) 1995-05-04
CA2134730A1 (en) 1995-05-04
FI945139A (en) 1995-05-04
CA2134730C (en) 2003-12-30
SE516814C2 (en) 2002-03-05
SE0103975L (en) 2001-12-10
FI945139A0 (en) 1994-11-01

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Legal Events

Date Code Title Description
CANC Patent cancelled, revoked after opposition
NUG Patent has lapsed