US3560330A - Multistage cellulose pulp bleaching with chlorine and chlorine dioxide - Google Patents

Multistage cellulose pulp bleaching with chlorine and chlorine dioxide Download PDF

Info

Publication number
US3560330A
US3560330A US613733A US3560330DA US3560330A US 3560330 A US3560330 A US 3560330A US 613733 A US613733 A US 613733A US 3560330D A US3560330D A US 3560330DA US 3560330 A US3560330 A US 3560330A
Authority
US
United States
Prior art keywords
pulp
chlorine
bleaching
stage
chlorine dioxide
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
US613733A
Other languages
English (en)
Inventor
Nils Knut Gabriel Ahlborg
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.)
Stora Enso Oyj
Original Assignee
Stora Kopparbergs Bergslags AB
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 Stora Kopparbergs Bergslags AB filed Critical Stora Kopparbergs Bergslags AB
Application granted granted Critical
Publication of US3560330A publication Critical patent/US3560330A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
    • D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
    • D21C9/142—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites with ClO2/Cl2 in a multistage process involving ClO2/Cl2 exclusively

Definitions

  • Chlorine bleaching of the unbleached pulp is usually effected at low temperatures (preferably below C.) and with low consistency (2.5-3.5 and short bleachof below 35 C. Small amounts of chlorine dioxide (0.5- 2 ing periods (3040 minutes)
  • the low Pulp consistency 2 gm./kilo of pulp may optionally be added to the elemental 'chlorinein the second chlorine treatment step. Subsequent treatment stages may 'follow which include alkali washes and chlorine dioxide bleachings.
  • the presence of discoloured fibre bundles may be due to the fact that owing to its denser structure a certain percentage of the wood was not sufficiently impregnated during the digestion process or beand long bleaching periods 3-6 hours).
  • the principle intention when bleaching screenedrchemical pulp is to increase the brightness of the pulp by retween chlorine and lignin is so high that at.high pulp concentrations difiiculties are met with in achieving ;a uniform distribution of the bleaching agent, resulting in non-uniform chlorination of the pulp, which' leads to an moving lignin and other substances. This is often effected 5 impaired bleaching result.
  • lignin is, to a certain extent, also released from the, in part, strongly lignin-containing fibre bundles (shives), whereby these can either be disintegrated completely into discrete fibres or disintegrated into smaller fibre bundles.
  • shives strongly lignin-containing fibre bundles
  • the colour of the shives may, at the same time, fade somewhat
  • the aforegoing concerning fibre bundles originating from the wood is also true for the particles of bark entrained with the pulp to the bleaching department.
  • thesaid maximum limit can be raised to include larger and larger particles; but this involves an increase in costs.
  • the maximum permitted size of contaminating wood and bark particles in the unbleached pulp varies firstly with the digesting process, which determines the EXAMPLE 1 2% shives of various thickness, calculated on the weight of the .pulp, obtained by fractioning screened reject removed from the screening section of the sulphite plant, was added to a two-stage sodium-sulphite pulp digested, washed and screened in the plant. The pulp was then bleached in five stages (C1 NaOH, C NaOH, C10
  • the temperatures at which the bleaching stage according to the invention is carried out need not be too high, suitably below 35 C., e.g. 2030 C., in orderto avoid oxidative decomposition of the pulp.
  • a small amount of C10 suitably 0.5-2 gram/kilo of pulp, calculated as active chlorine.
  • EXAMPLE 2 A two-stage sodium-sulphite pulp digested, washed and screened in the factory and to which was added 0.5% shives, calculated on the weight of the pulp, .'.having a thickness of 0.35-0.50 mm. and which were obtained by fractioning, in a slotted screen, screen rejects taken from the screening department of the sulphate plant, was bleached in five stages according to the bleaching sequence shives C1 NaOH, Cl +C1O NaOH, C10 for various lengths Normal 76% excess of tlme and at various pulp concentratlons in the third Test chlorination chlorine in 40 bleaching stage according to Table 2, but in other respects Pulp mixture Stage 1 Stage 1 under the same bleaching conditions and chemical charge.
  • the object of the present invention is to provide a EXAMPLE 3 simple and economic process for increasing the purity of the pulp.
  • a substantially pure and also brighter pulp is obtained by means of a process according to the invention in that the pulp in a prebleached state and high concentration is subjected within a multistage bleaching operation to an excess of chlorine.
  • the tests made have shown that subsequent to prebleaching the pulp, e.g. by chlorinating in diluted pulp suspension and subsequent alkali treatment bleaching stage according to Table 3, but in other respects under the sarne bleaching conditions and chemical charges.
  • the speck area obtained in the finally bleached pulp by the addition of shives was then determined.
  • the brightness and viscosity was also determined, the result can be seen from Table 3.
  • an amount of chlorine well sufiicient for the excess chlorinating treatment is added to the prebleached pulp, preferably so that the amount of residual chlorine reaches at least 2 grams per kilogram pulp, e.g. 2-10 grams per kilogram pulp.
  • a process for bleaching cellulose pulp in a sequence of bleaching stages with intermediate alkali treatment stages comprising treating the pulp with chlorine in a first chlorine bleaching stage at low pulp conicentration whereby during said chlorinebleaching stage and the subsequent alkali treatment stage, the' major portion of the lignin content of said pulp is removed, then treating the pulp in a second chlorine bleaching stagesat a pulp concentation of not less than 5% and a temperature of below C. with an excess of chlorine, and :thereafter treating; the pulp with chlorine dioxide in at.least one further bleaching stage.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
US613733A 1966-02-25 1967-02-03 Multistage cellulose pulp bleaching with chlorine and chlorine dioxide Expired - Lifetime US3560330A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE2506/66A SE313985B (enrdf_load_html_response) 1966-02-25 1966-02-25

Publications (1)

Publication Number Publication Date
US3560330A true US3560330A (en) 1971-02-02

Family

ID=20260076

Family Applications (1)

Application Number Title Priority Date Filing Date
US613733A Expired - Lifetime US3560330A (en) 1966-02-25 1967-02-03 Multistage cellulose pulp bleaching with chlorine and chlorine dioxide

Country Status (4)

Country Link
US (1) US3560330A (enrdf_load_html_response)
FI (1) FI48367C (enrdf_load_html_response)
GB (1) GB1170686A (enrdf_load_html_response)
SE (1) SE313985B (enrdf_load_html_response)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909194A (en) * 1972-05-30 1975-09-30 Pulp Paper Res Inst Bleaching of textiles with chlorine monoxide
US4255013A (en) * 1979-05-17 1981-03-10 John E. McNair Rifle scope having compensation for elevation and drift

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE458209B (sv) * 1987-06-04 1989-03-06 Nils Bertil Carnoe Saett att reducera miljoeskadliga klorfenolfoereningar vid klorblekning av cellulosamassa
RU2290469C1 (ru) * 2005-06-24 2006-12-27 Открытое акционерное общество "Центральный научно-исследовательский институт бумаги" (ОАО "ЦНИИБ") Способ многоступенчатой отбелки сульфитной целлюлозы

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909194A (en) * 1972-05-30 1975-09-30 Pulp Paper Res Inst Bleaching of textiles with chlorine monoxide
US4255013A (en) * 1979-05-17 1981-03-10 John E. McNair Rifle scope having compensation for elevation and drift

Also Published As

Publication number Publication date
GB1170686A (en) 1969-11-12
FI48367B (enrdf_load_html_response) 1974-05-31
FI48367C (fi) 1974-09-10
SE313985B (enrdf_load_html_response) 1969-08-25

Similar Documents

Publication Publication Date Title
US5296099A (en) Environmentally improved process for bleaching lignocellulosic materials with oxygen, ozone and chlorine dioxide
AU638017B2 (en) Environmentally improved process for bleaching lignocellulosic materials
US5164043A (en) Environmentally improved process for bleaching lignocellulosic materials with ozone
CA1084207A (en) Process for the bleaching of cellulose pulp
US5211811A (en) Process for high consistency oxygen delignification of alkaline treated pulp followed by ozone delignification
US5188708A (en) Process for high consistency oxygen delignification followed by ozone relignification
RU2439232C2 (ru) Способ отбеливания бумажной целлюлозной массы путем конечной обработки озоном при высокой температуре
US5173153A (en) Process for enhanced oxygen delignification using high consistency and a split alkali addition
US3919041A (en) Multi-stage chlorine dioxide delignification of wood pulp
US3560330A (en) Multistage cellulose pulp bleaching with chlorine and chlorine dioxide
US3532597A (en) Preparation of dissolving pulps from wood by hydrolysis and alkaline sulfite digestion
US3829357A (en) Oxidative manufacture of pulp with chlorine dioxide
US3586599A (en) Purification of fluffed or shredded pulp with chlorine dioxide
EP0128190A1 (en) PROCESS FOR DECOLORATION WITH PEROXIDE OF A MATERIAL CONTAINING CELLULOSE.
US2186034A (en) Pulp bleaching and refining process
US5217574A (en) Process for oxygen delignifying high consistency pulp by removing and recycling pressate from alkaline pulp
US1838326A (en) Refined wood pulp of low pentosan content
EP0206560A2 (en) Alkaline-peroxide-oxygen treatment for unbleached and chlorinated chemical pulps
US5441603A (en) Method for chelation of pulp prior to ozone delignification
US3617432A (en) Delignifying lignocellulose with an incomplete soda cook followed by gaseous bleaching
US1899637A (en) Chemical pulping and refining process
US1809286A (en) Pulp of high whiteness and strength and process of producing same
AU647485B2 (en) Pulp alkali addition process for high consistency oxygen delignification
US1811864A (en) Process of liberating fiber from bagasse or like stalks
US1987212A (en) Bleaching of cellulose fiber