SE501836C2 - Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step - Google Patents

Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step

Info

Publication number
SE501836C2
SE501836C2 SE9303066A SE9303066A SE501836C2 SE 501836 C2 SE501836 C2 SE 501836C2 SE 9303066 A SE9303066 A SE 9303066A SE 9303066 A SE9303066 A SE 9303066A SE 501836 C2 SE501836 C2 SE 501836C2
Authority
SE
Sweden
Prior art keywords
pulp
bleaching
treated
ozone
complexing
Prior art date
Application number
SE9303066A
Other languages
Swedish (sv)
Other versions
SE9303066L (en
SE9303066D0 (en
Inventor
Solveig Norden
Maarten Dahl
Original Assignee
Sunds Defibrator Ind 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 Sunds Defibrator Ind Ab filed Critical Sunds Defibrator Ind Ab
Priority to SE9303066A priority Critical patent/SE501836C2/en
Publication of SE9303066D0 publication Critical patent/SE9303066D0/en
Priority to AU77923/94A priority patent/AU7792394A/en
Priority to JP7509711A priority patent/JPH09503028A/en
Priority to CA002168445A priority patent/CA2168445A1/en
Priority to BR9407555A priority patent/BR9407555A/en
Priority to EP94928521A priority patent/EP0720675A1/en
Priority to PCT/SE1994/000758 priority patent/WO1995008666A1/en
Publication of SE9303066L publication Critical patent/SE9303066L/en
Publication of SE501836C2 publication Critical patent/SE501836C2/en
Priority to FI961279A priority patent/FI961279A/en
Priority to NO961139A priority patent/NO961139L/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
    • D21C9/1026—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
    • D21C9/147—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

Abstract

A method for bleaching lignocellulose-containing fiber material in the form of chemical pulp without using chloric bleaching agents where the pulp is treated with chelating agent and is bleached with ozone and peroxide. Immediately after the ozone bleaching the pulp is treated with chelating agent in a second chelating step at a pulp concentration of 1-10 % for 1-30 minutes at the temperature of 20-90 DEG C and the pH value 1,5-5. The pulp thus treated is washed and dewatered to a concentration of 8-40 % prior to the peroxide bleaching.

Description

501 836 2 Enligt föreliggande uppfinning elimineras dessa problem genom att förfarandet är förhållandevis enkelt samtidigt som det ger en hög ljushet hos massan. According to the present invention, these problems are eliminated in that the process is relatively simple while giving a high brightness of the pulp.

Uppfinningens kännetecken framgår av patentkraven.The features of the invention appear from the claims.

I det följande skall uppfinningen beskrivas närmare i anslutning till figuerna. Q Fig 1 är ett exempel på flödesschema för ett förfarande enligt uppfinningen. ' Fig 2 är ett diagram som visar ljusheten som funktion av väteperoxidsatsningen, dels för kända förfaranden och dels för ett förfarande enligt uppfinningen.In the following, the invention will be described in more detail in connection with the figures. Fig. 1 is an example of a flow chart for a method according to the invention. Fig. 2 is a diagram showing the brightness as a function of the hydrogen peroxide charge, partly for known processes and partly for a process according to the invention.

Enligt flödesschemat i fig l förs kemisk massa först till ett första komplexbildarsteg 10 för behandling med EDTA eller DTPA. Massakoncentrationen bör vara 1-10% och behand- lingen utföras under 1-60 minuter, lämpligen 5-30 minuter.According to the flow chart of Fig. 1, chemical pulp is first transferred to a first complexing step 10 for treatment with EDTA or DTPA. The pulp concentration should be 1-10% and the treatment is carried out for 1-60 minutes, preferably 5-30 minutes.

Temperaturen bör vara 20-70°C, lämpligen 20-40°C och pH-värdet 2-5.The temperature should be 20-70 ° C, preferably 20-40 ° C and the pH 2-5.

Efter det första komplexbildarsteget 10 tvättas och avvattnas massan, exempelvis i en tvättpress 11, för av- lägsnande av lösta metalljoner. Därifrån förs massan till ett ozonsteg 12 för ozonblekning. Omedelbart efter ozonsteget 12 späds massan till en koncentration av 1-10% och förs till ett andra komplexbildarsteg 13. Där utföres en behandling med komplexbildare, lämpligen DTPA eller EDTA, under 1-30 minuter, lämpligen 5-20 minuter, vid temperaturen 20-90°C, lämpligen 40-80°C och pH-värdet 1,5-5. Mängden satsad DTPA eller EDTA kan lämpligen vara upp till 0,5 kg/ton massa.After the first complexing step 10, the pulp is washed and dewatered, for example in a washing press 11, to remove dissolved metal ions. From there, the pulp is passed to an ozone stage 12 for ozone bleaching. Immediately after the ozone step 12, the pulp is diluted to a concentration of 1-10% and passed to a second complexing step 13. There, a treatment with complexing agents, preferably DTPA or EDTA, is carried out for 1-30 minutes, preferably 5-20 minutes, at the temperature 20- 90 ° C, preferably 40-80 ° C and the pH 1.5-5. The amount of DTPA or EDTA charged can suitably be up to 0.5 kg / ton pulp.

Efter detta andra komplexbildarsteg 13 utföres en tvättning och avvattning till en koncentration av 8-40% i ett andra tvättsteg 14 varefter massan förs till ett peroxidsteg 15 för peroxidblekning. 4 Enligt detta förfarande kan massan blekas till en ljushet överstigande 83% ISO.After this second complexing step 13, a washing and dewatering is carried out to a concentration of 8-40% in a second washing step 14, after which the pulp is passed to a peroxide step 15 for peroxide bleaching. According to this procedure, the pulp can be bleached to a brightness exceeding 83% ISO.

I diagrammet i fig 2 redovisas ljusheten som funktion av peroxidsatsningen vid olika typer av behandling mellan ozon och peroxidsteg.The diagram in Fig. 2 shows the brightness as a function of the peroxide investment in different types of treatment between ozone and peroxide steps.

Kurva 1 avser ett konventionellt förfarande med pe- roxidblekning efter enbart tvätt och avvattning av den ozon- 501 836 blekta massan.Curve 1 relates to a conventional process with peroxide bleaching after washing and dewatering of the ozone-bleached pulp only.

Kurva 2 avser peroxidblekning av ozonblekt massa som på känt sätt tvättats, avvattnats, komplexbildarbehandlats samt tvättats och avvattnats på nytt före peroxidblekningen.Curve 2 refers to peroxide bleaching of ozone-bleached pulp that has been washed, dewatered, complex image-treated in a known manner and washed and dewatered again before the peroxide bleaching.

Kurva 3 avser ett förfarande enligt uppfinningen.Curve 3 relates to a method according to the invention.

Av fig 2 framgår att blekningen enligt uppfinningen (kurva 3) ger ett väsentligt bättre resultat än konventionell blekning enligt kurva 1. Vidare framgår att blekningen enligt uppfinningen ger ett resultat som nära nog motsvarar resultatet av blekningen enligt kurva 3 trots att förfarandet enligt uppfinningen är betydligt enklare. Även erfarenheter från fabriksmiljö visar att skillnaden mellan de båda sistnämnda förfarandena (kurva 2 och 3) är mycket liten.Fig. 2 shows that the bleaching according to the invention (curve 3) gives a significantly better result than conventional bleaching according to curve 1. Furthermore, it appears that the bleaching according to the invention gives a result which closely corresponds to the result of the bleaching according to curve 3 despite the process according to the invention being significant. easier. Experience from the factory environment also shows that the difference between the two latter methods (curves 2 and 3) is very small.

Uppfinningen är givetvis inte begränsad till det visade utföringsexemplet utan kan varieras inom ramen för uppfin- ningstanken.The invention is of course not limited to the exemplary embodiment shown but can be varied within the scope of the inventive concept.

Claims (3)

501 836 Patentkrav501,836 Patent claims 1. Sätt för blekning av lignocellulosahaltigt fiber- material i form av kemisk massa utan användande av klorhaltiga blekmedel, varvid massan behandlas med komplexbildare samt bleks med ozon och peroxid, k ä n n e t e c k n a t av att massan omedelbart efter ozonblekningen behandlas med komplex- bildare i ett andra komplexbildarsteg vid en massakoncentra- tion av 1-10% under 1-30 minuter, varvid temperaturen är 20-90%Ioch pH-värdet 1,5-5, samt att den så behandlade massan tvättas och avvattnas till en koncentration av 8-40% före peroxidblekningen.A method for bleaching lignocellulosic fibrous material in the form of chemical pulp without the use of chlorine-containing bleaching agents, the pulp being treated with complexing agents and bleached with ozone and peroxide, characterized in that the pulp is treated with complexing agents in a second immediately after ozone bleaching. complexing steps at a pulp concentration of 1-10% for 1-30 minutes, the temperature being 20-90% and the pH value 1.5-5, and the pulp thus treated being washed and dewatered to a concentration of 8-40%. % before peroxide bleaching. 2. Sätt enligt kravet 1, k ä n n e t e c k n a t av att Vsom komplexbildare i det andra komplexbildarsteget används DTPA eller EDTA som tillsätts i en mängd av upp till 0,5 kg per ton massa.2. A method according to claim 1, characterized in that VTPA or EDTA is used as complexing agent in the second complexing step which is added in an amount of up to 0.5 kg per tonne of pulp. 3. Sätt enligt kravet 1 eller 2, k ä n n e t e c k n a t av att blekningen utföres till en ljushet överstigande 83% ISO.3. A method according to claim 1 or 2, characterized in that the bleaching is carried out to a brightness exceeding 83% ISO.
SE9303066A 1993-09-21 1993-09-21 Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step SE501836C2 (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
SE9303066A SE501836C2 (en) 1993-09-21 1993-09-21 Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step
PCT/SE1994/000758 WO1995008666A1 (en) 1993-09-21 1994-08-22 Chlorine-free bleaching of chemical pulp involving a two stage treatment with chelating agent
BR9407555A BR9407555A (en) 1993-09-21 1994-08-22 Process for bleaching fiber material containing lignocellulose in the form of chemical pulp without using chlorine bleaching agents
JP7509711A JPH09503028A (en) 1993-09-21 1994-08-22 Chlorine-free bleaching of chemical pulp including two-step treatment with chelating agents
CA002168445A CA2168445A1 (en) 1993-09-21 1994-08-22 Chlorine-free bleaching of chemical pulp involving a two stage treatment with chelating agent
AU77923/94A AU7792394A (en) 1993-09-21 1994-08-22 Chlorine-free bleaching of chemical pulp involving a two stage treatment with chelating agent
EP94928521A EP0720675A1 (en) 1993-09-21 1994-08-22 Chlorine-free bleaching of chemical pulp involving a two stage treatment with chelating agent
FI961279A FI961279A (en) 1993-09-21 1996-03-20 Chlorine-free chemical pulp bleaching comprising a two-stage treatment with chelating agent
NO961139A NO961139L (en) 1993-09-21 1996-03-20 Chlorine-free chemical pulp bleaching by two-stage bleaching with chelating agent

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9303066A SE501836C2 (en) 1993-09-21 1993-09-21 Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step

Publications (3)

Publication Number Publication Date
SE9303066D0 SE9303066D0 (en) 1993-09-21
SE9303066L SE9303066L (en) 1995-03-22
SE501836C2 true SE501836C2 (en) 1995-05-22

Family

ID=20391160

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9303066A SE501836C2 (en) 1993-09-21 1993-09-21 Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step

Country Status (9)

Country Link
EP (1) EP0720675A1 (en)
JP (1) JPH09503028A (en)
AU (1) AU7792394A (en)
BR (1) BR9407555A (en)
CA (1) CA2168445A1 (en)
FI (1) FI961279A (en)
NO (1) NO961139L (en)
SE (1) SE501836C2 (en)
WO (1) WO1995008666A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE504803C2 (en) * 1995-08-24 1997-04-28 Sunds Defibrator Ind Ab Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing
SE508239C2 (en) * 1997-01-03 1998-09-21 Sunds Defibrator Ind Ab Treatment of pulp with complexing agents in at least one mixing step, without the use of the bleaching tower
CN102587186B (en) * 2012-03-20 2015-03-11 昆明理工大学 Method for bleaching dendrocalamus giganteus chemical pulp
RU2634586C1 (en) * 2016-08-01 2017-10-31 федеральное государственное бюджетное образовательное учреждение высшего образования "Пермский национальный исследовательский политехнический университет" Method of bleaching hardwood sulphate cellulose

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0565625A1 (en) * 1991-01-03 1993-10-20 Union Camp Patent Holding, Inc. Chlorine-free process for bleaching lignocellulosic pulp
SE468355B (en) * 1991-04-30 1992-12-21 Eka Nobel Ab CHEMISTRY OF CHEMICAL MASS THROUGH TREATMENT WITH COMPLEX PICTURES AND OZONE

Also Published As

Publication number Publication date
NO961139D0 (en) 1996-03-20
FI961279A0 (en) 1996-03-20
NO961139L (en) 1996-03-20
FI961279A (en) 1996-03-20
CA2168445A1 (en) 1995-03-30
JPH09503028A (en) 1997-03-25
BR9407555A (en) 1996-12-31
SE9303066L (en) 1995-03-22
SE9303066D0 (en) 1993-09-21
WO1995008666A1 (en) 1995-03-30
EP0720675A1 (en) 1996-07-10
AU7792394A (en) 1995-04-10

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