SE504803C2 - Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing - Google Patents

Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing

Info

Publication number
SE504803C2
SE504803C2 SE9502962A SE9502962A SE504803C2 SE 504803 C2 SE504803 C2 SE 504803C2 SE 9502962 A SE9502962 A SE 9502962A SE 9502962 A SE9502962 A SE 9502962A SE 504803 C2 SE504803 C2 SE 504803C2
Authority
SE
Sweden
Prior art keywords
pulp
mixing
mixing steps
complexing agent
complexing agents
Prior art date
Application number
SE9502962A
Other languages
Swedish (sv)
Other versions
SE9502962L (en
SE9502962D0 (en
Inventor
Ulf Germgaard
Jonas Lindquist
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=20399294&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=SE504803(C2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Sunds Defibrator Ind Ab filed Critical Sunds Defibrator Ind Ab
Priority to SE9502962A priority Critical patent/SE504803C2/en
Publication of SE9502962D0 publication Critical patent/SE9502962D0/en
Priority to EP96928765A priority patent/EP0846199B1/en
Priority to CA002229212A priority patent/CA2229212A1/en
Priority to DE69611680T priority patent/DE69611680T2/en
Priority to PCT/SE1996/000996 priority patent/WO1997008380A1/en
Priority to PT96928765T priority patent/PT846199E/en
Priority to AU68399/96A priority patent/AU6839996A/en
Priority to ES96928765T priority patent/ES2153593T3/en
Priority to AT96928765T priority patent/ATE198916T1/en
Priority to BR9610199A priority patent/BR9610199A/en
Publication of SE9502962L publication Critical patent/SE9502962L/en
Publication of SE504803C2 publication Critical patent/SE504803C2/en
Priority to NO980753A priority patent/NO980753L/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

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Cosmetics (AREA)
  • Detergent Compositions (AREA)

Abstract

A method of chlorine-free bleaching of pulp where metals are removed by means of a chelating agent. The chelating agent is admixed to the pulp in at least two subsequent mixing steps without intermediate washing. The stay-time between the mixing steps shall be less than 15 minutes, and the pulp is washed after the last mixing step.

Description

504 803 tvättsteg där de frilagda och komplexbunda metalljonerna tvättas ut. Den frilagda vätskan som är anrikad på metalljoner går oftast till avlopp. 504 803 washing steps where the exposed and complexed metal ions are washed out. The exposed liquid that is enriched in metal ions usually goes to the drain.

De betingelser som normalt används i ett Q-steg är en temperatur på 70-90°C, en uppehållstid på 1-2 timmar, massa- koncentration 10-14%, pH 5-7 och komplexbildarsatsning 1-3 kg per ton massa. Från en strikt blekningssynpunkt är Q-steget egentligen ett onödigt behandlingssteg eftersom ingen ljushetshöjning sker där. Q-behandlingen är dock nödvändig för en framgångsrik klorfri blekning som framgått ovan. Om Q-steget kunde förenklas utan att effektiviteten i elimineringen av metaller minskade skulle stora besparingar kunna uppnås eftersom ett fullständigt bleksteg med blekningstorn är dyrbart.The conditions normally used in a Q-step are a temperature of 70-90 ° C, a residence time of 1-2 hours, pulp concentration 10-14%, pH 5-7 and complexing agent charge 1-3 kg per tonne of pulp. From a strictly bleaching point of view, the Q-step is actually an unnecessary treatment step because no increase in brightness takes place there. However, the Q-treatment is necessary for a successful chlorine-free bleaching as stated above. If the Q-step could be simplified without reducing the efficiency in the elimination of metals, large savings could be achieved because a complete bleaching step with bleaching tower is expensive.

Föreliggande uppfinning är inriktad på en lösning av ovanstående problem. Uppfinningen medför således en effektivi- sering av Q-steget genom att metallerna elimineras effektivt samtidigt som Q-steget förenklas med minskad investeringskostnad som följd i förhållande till ett konventionellt Q-steg.The present invention is directed to a solution to the above problems. The invention thus entails a streamlining of the Q-step by efficiently eliminating the metals at the same time as the Q-step is simplified with reduced investment cost as a result in relation to a conventional Q-step.

Uppfinningen är baserad på att det överraskande visat sig att Q-stegets effektivitet är avsevärt mindre påverkad av ökad reaktionstemperatur än av ökad retentionstid. Detta antyder enligt klassisk kemisk kinetik att Q-steget är diffusionsstyrt och inte reaktionstyrt. Detta medför att Q-steget bör utföras så att diffusionen underlättas och om detta görs effektivt kan därmed den totala retentionstiden ansevärt minskas.The invention is based on the fact that it has surprisingly been found that the efficiency of the Q-step is considerably less affected by increased reaction temperature than by increased retention time. According to classical chemical kinetics, this indicates that the Q-step is diffusion-controlled and not reaction-controlled. This means that the Q-step should be performed so that the diffusion is facilitated and if this is done efficiently, the total retention time can thus be considerably reduced.

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

Det bästa sättet att minska diffusionsmotståndet är att minska diffusionsavståndet för aktiva reaktanter och utlösta reaktionsprodukter och detta görs i teknisk skala genom effektiv omblandning, lämpligen i en mixer. Genom upprepad effektiv omblandning kan således retentionstiden i Q-steget minskas.The best way to reduce the diffusion resistance is to reduce the diffusion distance of active reactants and triggered reaction products and this is done on a technical scale by efficient mixing, preferably in a mixer. Thus, by repeated efficient mixing, the retention time in the Q-step can be reduced.

Antalet blandningssteg bör vara minst två, företrädesvis minst tre. Av ekonomiska skäl måste dock antalet blandningssteg och därmed antalet mixrar hållas på en rimlig nivå. Ett lämpligt antal kan vara 2-4 steg. En viss retentionstid mellan blandningsstegen är av godo, men denna tid behöver inte vara lång, eftersom diffusionshastigheten utan omblandning ändå är avsevärt so4 so3 långsammare än vad som kan uppnås genom omblandning, exempelvis i en mixer. Uppehållstiden mellan blandningsstegen skall således vara kort, mindre än 15 minuter, lämpligen mindre än 10 minuter och företrädesvis mindre än 5 minuter. Vidare skall blandnings- stegen utföras efter varandra utan mellanliggande tvätt. Den tvätt som erfordras för att avlägsna metallerna från massasuspensionen skall utföras efter det sista blandningssteget.The number of mixing steps should be at least two, preferably at least three. For economic reasons, however, the number of mixing steps and thus the number of mixers must be kept at a reasonable level. A suitable number can be 2-4 steps. A certain retention time between the mixing steps is good, but this time does not have to be long, since the diffusion rate without mixing is still considerably so4 so3 slower than what can be achieved by mixing, for example in a mixer. The residence time between the mixing steps should thus be short, less than 15 minutes, suitably less than 10 minutes and preferably less than 5 minutes. Furthermore, the mixing steps must be performed one after the other without intermediate washing. The washing required to remove the metals from the pulp suspension must be carried out after the last mixing step.

Komplexbildaren är lämpligen av typ EDTA (ethylenediamine- tetraacetic acid) eller DTPA (diethylenetriaminepentaacetic acid), men även andra typer av komplexbildare kan användas, exempelvis NTA (nitrilotriacetic acid) eller DTPMP (diethylenetriaminepenta- methylenephosphonic acid). Den totala mängden tillsatt komplex- bildare bör vara 0,5 - 5 kg per ton massa (räknat som ren komplexbildare), företrädesvis l - 3 kg per ton massa.The complexing agent is suitably of the type EDTA (ethylenediaminetetraacetic acid) or DTPA (diethylenetriaminepentaacetic acid), but other types of complexing agents can also be used, for example NTA (nitrilotriacetic acid) or DTPMP (diethylenetriaminepentamethylenephosphonic acid). The total amount of complexing agent added should be 0.5 - 5 kg per tonne of pulp (calculated as pure complexing agent), preferably 1 - 3 kg per tonne of pulp.

Hela tillsatsen av komplexbildare kan göras i det första blandningssteget varvid efterföljande blandningssteg enbart åstad- kommer en förnyad omblandning. Alternativt kan komplexbildaren tillsättas i flera av blandningsstegen. Tillsatsen bör då huvudsakligen göras i första steget och tillsatsmängden i efterföljande steg bör understiga 2 kg per ton massa per steg.The entire addition of complexing agents can be done in the first mixing step, whereby subsequent mixing steps only provide a renewed mixing. Alternatively, the complexing agent may be added in several of the mixing steps. The addition should then mainly be made in the first step and the amount of additive in the subsequent steps should be less than 2 kg per tonne of pulp per step.

Temperaturen i blandningsstegen bör vara över 70°C och lämpligen över 80°C. Ett föredraget temperaturintervall är 80 - 120 °C.The temperature in the mixing steps should be above 70 ° C and preferably above 80 ° C. A preferred temperature range is 80 - 120 ° C.

Trycket i hela Q-steget bör lämpligen vara 1 - 10 bar.The pressure in the entire Q-stage should suitably be 1 - 10 bar.

Särskilt effektiv inblandning kan åstadkommas genom användning av högintensiva mixrar som bryter upp fibernätverket i massan och åstadkommer en nära kontakt mellan fibrer och komplexbildare.Particularly effective mixing can be achieved by using high-intensity mixers which break up the fiber network in the pulp and provide a close contact between fibers and complexing agents.

Uppfinningen är givetvis inte begränsad till ovan angivna utföranden utan kan varieras inom ramen för uppfinningstanken.The invention is of course not limited to the above-mentioned embodiments but can be varied within the scope of the inventive idea.

Claims (9)

504 sus 4 Patentkrav504 sus 4 Patentkrav 1. Sätt vid klorfri blekning av massa där metaller avlägsnas med hjälp av en komplexbildare, k ä n n e t e c k n a t a v att komplexbildaren blandas med massan utan användning av bleknings- torn i minst två på varandra följande blandningssteg utan mellan- liggande tvätt, att tidsuppehållet mellan blandningsstegen är mindre än 15 minuter och att massan tvättas efter det sista blandningssteget.1. In the case of chlorine-free bleaching of pulp where metals are removed by means of a complexing agent, characterized in that the complexing agent is mixed with the pulp without using the bleaching tower in at least two successive mixing steps without intermediate washing, that the time interval between mixing steps is shorter than 15 minutes and that the mass is washed after the last mixing step. 2. Sätt enligt kravet 1, k ä n n e t e c k n a t a v att hela tillsatsen av komplexbildare görs i det första blandnings-steget varvid efterföljande blandningssteg enbart åstadkommer en förnyad omblandning.2. A method according to claim 1, characterized in that the entire addition of complexing agents is made in the first mixing step, the subsequent mixing steps only producing a renewed mixing. 3. Sätt enligt kravet l, k ä n n e t e c k n a t a V att komplexbildaren tillsätts i flera blandningssteg.3. A method according to claim 1, wherein the complexing agent is added in several mixing steps. 4. Sätt enligt något av föregående krav, k ä n n e t e c k n a t a v att hela tillsatsen av komplexbildare uppgår till 0,5 - 5 kg per ton massa, företrädesvis l - 3 kg per ton massa.4. A method according to any one of the preceding claims, characterized in that the entire addition of complexing agents amounts to 0.5 - 5 kg per tonne of pulp, preferably 1 - 3 kg per tonne of pulp. 5. Sätt enligt något av föregående krav, k ä n n e t e c k n a t a v att temperaturen i blandningsstegen är över 70°C.5. A method according to any one of the preceding claims, characterized in that the temperature in the mixing steps is above 70 ° C. 6. Sätt enligt något av föregående krav, k ä n n e t e c k n a t a v att komplexbildaren är av typ EDTA eller DTPA.6. A method according to any one of the preceding claims, characterized in that the complexing agent is of the EDTA or DTPA type. 7. Sätt enligt något av kraven 1 - 5, k ä n n e t e c k n a t a v att komplexbildaren är av typ NTA eller DTPMP.A method according to any one of claims 1 - 5, characterized in that the complexing agent is of the type NTA or DTPMP. 8. Sätt enligt något av föregående krav, k ä n n e t e c k n a t a v att inblandningen av komplexbildaren sker medelst höginten- siva mixrar som bryter upp fibernätverket i massan och åstadkommer en nära kontakt mellan fibrer och komplexbildare.8. A method according to any one of the preceding claims, characterized in that the mixing of the complexing agent takes place by means of high-intensity mixers which break up the fiber network in the pulp and establish a close contact between fibers and complexing agents. 9. Sätt enligt något av föregående krav, k ä n n e t e c k n a t a v att blandningsstegen utförs vid ett tryck av 1 - 10 bar.9. A method according to any one of the preceding claims, characterized in that the mixing steps are carried out at a pressure of 1 - 10 bar.
SE9502962A 1995-08-24 1995-08-24 Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing SE504803C2 (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
SE9502962A SE504803C2 (en) 1995-08-24 1995-08-24 Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing
BR9610199A BR9610199A (en) 1995-08-24 1996-08-09 Chlorine-free pulp bleaching process
AT96928765T ATE198916T1 (en) 1995-08-24 1996-08-09 PULP TREATMENT WITH A COMPLEX FORMING AGENT IN AT LEAST TWO MIXING STAGES WITHOUT INTERMEDIATE WASHING
EP96928765A EP0846199B1 (en) 1995-08-24 1996-08-09 Treatment of pulp with chelating agent in at least two mixing steps without intermediate washing
CA002229212A CA2229212A1 (en) 1995-08-24 1996-08-09 Treatment of pulp with chelating agent in at least two mixing steps without intermediate washing
DE69611680T DE69611680T2 (en) 1995-08-24 1996-08-09 Cellulose treatment with a complexing agent in at least two mixing stages without intermediate washing
PCT/SE1996/000996 WO1997008380A1 (en) 1995-08-24 1996-08-09 Treatment of pulp with chelating agent in at least two mixing steps without intermediate washing
PT96928765T PT846199E (en) 1995-08-24 1996-08-09 TREATMENT OF PASTE WITH CHELATING AGENT AT LEAST TWO STEPS OF MIXTURE WITHOUT INTERMEDIATE WASHING
AU68399/96A AU6839996A (en) 1995-08-24 1996-08-09 Treatment of pulp with chelating agent in at least two mixing steps without intermediate washing
ES96928765T ES2153593T3 (en) 1995-08-24 1996-08-09 TREATMENT OF A PAPER PASTE WITH A CHELATING AGENT IN AT LEAST TWO STAGES OF MIXING WITHOUT INTERMEDIATE WASHING.
NO980753A NO980753L (en) 1995-08-24 1998-02-23 Treatment of pulp with chelating agent in at least two steps without intermediate washing

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9502962A SE504803C2 (en) 1995-08-24 1995-08-24 Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing

Publications (3)

Publication Number Publication Date
SE9502962D0 SE9502962D0 (en) 1995-08-24
SE9502962L SE9502962L (en) 1997-02-25
SE504803C2 true SE504803C2 (en) 1997-04-28

Family

ID=20399294

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9502962A SE504803C2 (en) 1995-08-24 1995-08-24 Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing

Country Status (11)

Country Link
EP (1) EP0846199B1 (en)
AT (1) ATE198916T1 (en)
AU (1) AU6839996A (en)
BR (1) BR9610199A (en)
CA (1) CA2229212A1 (en)
DE (1) DE69611680T2 (en)
ES (1) ES2153593T3 (en)
NO (1) NO980753L (en)
PT (1) PT846199E (en)
SE (1) SE504803C2 (en)
WO (1) WO1997008380A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
BRPI0909931B1 (en) 2008-06-20 2020-04-07 Int Paper Co composition for use in papermaking, method for making an embossing sheet, method for forming an image and embossing sheet

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69004492T3 (en) * 1989-06-06 2001-11-15 Eka Nobel Ab, Bohus Process for bleaching pulps containing lignocellulose.
SE469387B (en) * 1992-05-11 1993-06-28 Kamyr Ab SEATING WHITE PILLOW WITHOUT USING CHLORIC CHEMICALS
SE502665C2 (en) * 1993-06-11 1995-12-04 Kvaerner Pulping Tech Methods and reactor for ozone bleaching
SE501836C2 (en) * 1993-09-21 1995-05-22 Sunds Defibrator Ind Ab Bleaching of chemical pulp whereby the pulp is treated with complexing agents before and after an ozone step

Also Published As

Publication number Publication date
DE69611680D1 (en) 2001-03-01
DE69611680T2 (en) 2001-05-10
SE9502962L (en) 1997-02-25
ATE198916T1 (en) 2001-02-15
SE9502962D0 (en) 1995-08-24
BR9610199A (en) 1998-08-04
WO1997008380A1 (en) 1997-03-06
NO980753D0 (en) 1998-02-23
ES2153593T3 (en) 2001-03-01
PT846199E (en) 2001-06-29
NO980753L (en) 1998-02-24
AU6839996A (en) 1997-03-19
CA2229212A1 (en) 1997-03-06
EP0846199A1 (en) 1998-06-10
EP0846199B1 (en) 2001-01-24

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