EP1036237A1 - Perfectionnements apportes au procede de blanchiment de la pate chimique et dispersions intermediaires de pate - Google Patents

Perfectionnements apportes au procede de blanchiment de la pate chimique et dispersions intermediaires de pate

Info

Publication number
EP1036237A1
EP1036237A1 EP97952831A EP97952831A EP1036237A1 EP 1036237 A1 EP1036237 A1 EP 1036237A1 EP 97952831 A EP97952831 A EP 97952831A EP 97952831 A EP97952831 A EP 97952831A EP 1036237 A1 EP1036237 A1 EP 1036237A1
Authority
EP
European Patent Office
Prior art keywords
pulp
acid derivative
disuccinic acid
polyamino disuccinic
process according
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.)
Ceased
Application number
EP97952831A
Other languages
German (de)
English (en)
Inventor
Philippe Willems
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.)
Tate and Lyle Europe NV
Original Assignee
Tate and Lyle Europe NV
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 Tate and Lyle Europe NV filed Critical Tate and Lyle Europe NV
Publication of EP1036237A1 publication Critical patent/EP1036237A1/fr
Ceased 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
    • D21C9/1026—Other features in bleaching processes
    • D21C9/1042—Use of chelating agents

Definitions

  • the invention relates to an improved process for bleaching 5 chemical pulp or Kraft pulp.
  • the invention relates to such a process in which ethylendiamine disuccinate (EDDS) is used as a chelating agent during the treatment of the pulp.
  • EDDS ethylendiamine disuccinate
  • the most efficient way to remove these metal ions is by chelation. The chelates formed can then be removed by
  • Addition of chelating agents is normally done after the oxygen delignification step. Also addition of chelating agents during the bleaching step is described.
  • Alkaline conditions here mean a starting pH above 12, decreasing during the delignification step to pH 10-11.
  • the pulp after oxygen delignification can then be rinced.
  • WO- 9428464 suggests the use of polyamino disuccinic acids (EDDS) in pulp and paper processing to enhance or maintain bleaching effectiveness.
  • EDDS polyamino disuccinic acids
  • WO-9730209 a bleaching process for pulps was described, using EDDS as chelating agents during the pretreatment of chemical pulp, before peroxide bleaching. It is stated that the use of EDDS instead of EDTA or DTPA allows higher pH conditions during the Q-step, namely pH 4 - 8, preferabbly 6.5 - 7.5, instead of the standard values of 5-6. This results in a reduction of chemicals to be added to neutralise and/or alkalinise the pulp.
  • a process for bleaching alkaline oxygen delignified pulp is provided which is characterised in that a polyamino disuccinic acid derivative is used as the chelating agent at pH values above 9,5 before and/or during the peroxide bleaching step.
  • polyamino disuccinic acid derivates as used herein comprises the different optical isomers such as the
  • EDDS ethylenediamine disuccinate
  • the pretreated oxygen delignified pulp is washed with alkaline rinse waters coming from later alkaline peroxide bleaching steps, this before the first bleaching step. Rinse waters from the bleaching operation can thus be used in counter current.
  • the polyamino disuccinic acid derivative chelating agent is preferably used at pH-values varying between 10 and 11.
  • the concentration of polyamino disuccinic acid derivative on pulp dry substance may vary between 0,05-1% w/w, preferably between 0,2 and 0,8% w/w, and more preferably between 0,4 and 0,7% w/w.
  • Example 1 The invention will be further illustrated in the following examples.
  • Example 1 Example 1 :
  • the pulp used in this test is a resinous Kraft pulp, oxygen delignified, with the following characteristics :
  • the chelation stage Q was performed on a 10% consistency pulp at 80°C, during 60 minutes, in a polyethylene bag.
  • pH was adjusted with NaOH on a pulp already containing the chelating agent.
  • the pulp is washed with deionised water.
  • cation content in the pulp after the chelating step Q was determined by the following method : the organic matter is incinerated at 425°C. The ashes are then dissolved in hydrochloric acid and the cations are determined by Inductive Coupled Plasma (ICP) spectrometry. Kappa-index and Dpv are determined according to the ISO standards (ISO R302) . Results of these determinations are give in table 1.
  • the pulp is washed with deionised water. Then the pulp is brought to a consistency of 10%.
  • the bleaching step is performed for two hours in a polyethylene bag. After the P step the pulp is washed with deionised water. Then brightness is determined according to the ISO standard (ISO2470) . Results of the peroxide bleaching step are given for different chelating agents at different concentrations in table 2.
  • Table 2 Pulp brightness in function of chelating conditions and bleaching conditions of different concentrations of EDTA, DTPA and EDDS versus bianco.
  • EDDS is compared to EDTA and DTPA in the following test.
  • test solutions are then left alone at 40°C during two hours. After that period hyrogen peroxide loss is determined by adding excess potassium iodide and backtitration with thiosulfate. The following results were obtained.

Landscapes

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

Abstract

L'invention concerne un procédé pour blanchir de la pâte chimique, comportant une étape de délignification à l'oxygène alcalin et une étape subséquente de blanchiment au peroxyde d'hydrogène, et consistant à éliminer les ions métalliques indésirables avant et/ou pendant l'étape de blanchiment au peroxyde, au moyen d'un chélateur, un dérivé d'acide polyaminodisuccinique, de préférence du disuccinate d'éthylendiamine, étant utilisé comme chélateur à un pH supérieur à 9,5, de préférence compris entre 10 et 11. L'invention concerne également des dispersions intermédiaires de pâtes contenant un dérivé d'acide polyaminodisuccinique, de préférence du disuccinate d'éthylendiamine, en une concentration de 0,01 à 2,5 % en poids sur une substance de pâte sèche et à un pH supérieur à 9,5.
EP97952831A 1997-11-25 1997-11-25 Perfectionnements apportes au procede de blanchiment de la pate chimique et dispersions intermediaires de pate Ceased EP1036237A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP1997/006696 WO1999027178A1 (fr) 1997-11-25 1997-11-25 Perfectionnements apportes au procede de blanchiment de la pate chimique et dispersions intermediaires de pate

Publications (1)

Publication Number Publication Date
EP1036237A1 true EP1036237A1 (fr) 2000-09-20

Family

ID=8166803

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97952831A Ceased EP1036237A1 (fr) 1997-11-25 1997-11-25 Perfectionnements apportes au procede de blanchiment de la pate chimique et dispersions intermediaires de pate

Country Status (4)

Country Link
EP (1) EP1036237A1 (fr)
AU (1) AU5657098A (fr)
CA (1) CA2310278A1 (fr)
WO (1) WO1999027178A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6702921B2 (en) * 2001-05-01 2004-03-09 Ondeo Nalco Company Methods to enhance pulp bleaching and delignification using an organic sulfide chelating agent
EP1811080A1 (fr) * 2006-01-24 2007-07-25 Solvay SA Procédé de blanchiment de pate de papier mecanique
GB0721587D0 (en) 2007-11-02 2007-12-12 Innospec Ltd Process for bleaching pulp
CN115678439B (zh) * 2022-10-31 2024-04-23 上海应用技术大学 一种抑制铜钴电偶腐蚀的碱性抛光液及其制备方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE97179T1 (de) * 1989-06-06 1993-11-15 Eka Nobel Ab Verfahren zum bleichen von lignocellulose enthaltenden zellstoffen.
GB2293020B (en) * 1993-05-20 1997-08-27 Dow Chemical Co Succinic acid derivative degradable chelants, uses and compositions thereof
SE9501623L (sv) * 1995-05-02 1996-11-03 Sunds Defibrator Ind Ab Blekning av massa
SE9503004L (sv) * 1995-08-30 1997-03-01 Sunds Defibrator Ind Ab Blekning av massa
FI115469B (fi) * 1996-02-19 2005-05-13 Kemira Oyj Menetelmä kemiallisen selluloosamateriaalin käsittelemiseksi

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9927178A1 *

Also Published As

Publication number Publication date
CA2310278A1 (fr) 1999-06-03
WO1999027178A1 (fr) 1999-06-03
AU5657098A (en) 1999-06-15

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