EP0693144A1 - Procede d'epuration d'eau de traitement - Google Patents
Procede d'epuration d'eau de traitementInfo
- Publication number
- EP0693144A1 EP0693144A1 EP94911328A EP94911328A EP0693144A1 EP 0693144 A1 EP0693144 A1 EP 0693144A1 EP 94911328 A EP94911328 A EP 94911328A EP 94911328 A EP94911328 A EP 94911328A EP 0693144 A1 EP0693144 A1 EP 0693144A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- process water
- metal ions
- pulp
- alkaline liquid
- bleaching
- 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
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
- D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
-
- 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
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1026—Other features in bleaching processes
Definitions
- This invention relates to a method of treating process water containing metal ions, in connection with the bleaching of pulp of lignocellulose-containing material.
- the metal ions enter the system via the wood raw material and, therefore, the affluent of metal ions cannot be eliminated as would be desirable for process reasons.
- the content of these metal ions in the pulp is very low and, therefore, they do not cause any environmental problem, not in the local working environment and not in the recipient, either.
- the bleaching of papermaking pulp will be based to a high degree on hydroperoxide bleaching and ozone bleaching.
- this type of bleaching requires the unbleached pulp and process water to be free, or substantially free, of certain metal ions, because otherwise a considerable decomposition of charged hydroperoxide to water and oxygen and, respectively, of charged ozone to oxygen will take place, without any simultaneous bleaching effect .
- the pulp In order to remove the metal ions prior to bleaching, the pulp must be pretreated with chemicals, for example chelating agents such as EDTA or DTPA , which selectively bind the undesired metal ions and thereby render it possible to wash them out prior to the bleaching. For process reasons, the resulting washing water must be eliminated from the system, and at the same time environmental reasons require that the washing water is not emitted.
- the present invention offers a solution for the aforesaid problems.
- the invention thus, has the object to remove these metal ions from the process water in the bleach plant and thereby render it possible to close the wastewater system of the bleach plant without causing problems at the bleaching.
- Fig. 2 is a diagram showing the manganese content as a function of the reaction time at one embodiment.
- Unbleached pulp is supplied through a duct 1 to a pretreatment step 2 where the pulp is treated with chelating agents of the type EDTA or DTPA. Metals such as manganese are here solved out of the fiber material.
- the pulp is directed from here to a first washing step 3, for example in the form of a washing press or washing filter where wastewater containing the critical metal ions is removed through a duct 4.
- the pulp free of critical metal ions is directed to a bleaching step 5 for being bleached with hydroperoxide or ozone.
- the pulp is directed to a second washing step 6, from where the washed pulp is removed through a duct 7.
- the wastewater removed through the duct 4 is directed to a vessel 8 where the wastewater is brought into contact with an alkaline liquid, which preferably also contains sulphide, for example green liquor or white liquor from a sulphate pulp mill.
- an alkaline liquid which preferably also contains sulphide, for example green liquor or white liquor from a sulphate pulp mill.
- the metal ions are precipitated mainly as compounds difficult to solve in the form of hydroxides and sulphides. These difficultly soluble compounds thereafter can be separated from the liquid phase in a suitable way, for example by sedimentation, filtering or the like.
- the wastewater free of metal ions thereby can be used as washing water in positions where a low content of metals is of importance, for example in a bleach plant entirely free of chlorine.
- the waste ⁇ water from the vessel 8 is removed through a duct 9 and can be used again as washing water in other process steps .
- the precipitated metal compounds can be recycled through a duct 10 to the chemical recovery plant of the pulp mill, where they gradually will be ejected, for example into the green liquor slime. This eject passage exists already previously and, therefore, does not additionally harm the environment.
- the precipitated metal compounds are ejected directly out of the system without passing through the chemical recovery plant.
- the undesired metals thus, are i-n both cases transported out of the bleach plant, and the accumulation effect in the bleach plant thereby can be avoided when the drain system is closed.
- the method does not include an evaporation process, the energy balance of the mill is not deteriorated, either.
- suitable conditions for achieving an effective elimination of the metal ions in the reaction vessel 8 shall be an alkaline pH, preferably higher than pH 11 at room or higher temperature .
- the reaction time can be very short, less than 1 minute. A longer reaction time, 1--60 minutes, however, has no detrimental effect on the precipitation reaction.
- the amount of charged hydroxide and sulphide shall exceed the stoichiometric demand in order to bind the undesired metals.
- Fig. 1 where the manganese content is shown as a function of the reaction time; As appears from the diagram, the manganese content decreases rapidly, in less than 1 minute, at both green liquor charges from 1.4 mg/1 to below 0.2 mg/1. Thereafter an insignificant additional decrease of the manganese content at longer reaction times is observed.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Removal Of Specific Substances (AREA)
- Paper (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Physical Water Treatments (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
Procédé d'épuration d'eau de traitement contenant des ions métal relatif au blanchiment de pâte de matière lignocellulosique. L'eau de traitement est mise en contact avec un liquide alcalin contenant, de préférence, également du sulfure, ce qui provoque la précipitation des ions métal sous forme de composés métalliques difficilement solubles. Les composés métalliques précipités sont ensuite séparés de l'eau de traitement.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9301161A SE9301161L (sv) | 1993-04-07 | 1993-04-07 | Förfarande för behandling av processvatten |
SE9301161 | 1993-04-07 | ||
PCT/SE1994/000130 WO1994023122A1 (fr) | 1993-04-07 | 1994-02-17 | Procede d'epuration d'eau de traitement |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0693144A1 true EP0693144A1 (fr) | 1996-01-24 |
Family
ID=20389509
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94911328A Ceased EP0693144A1 (fr) | 1993-04-07 | 1994-02-17 | Procede d'epuration d'eau de traitement |
Country Status (12)
Country | Link |
---|---|
EP (1) | EP0693144A1 (fr) |
JP (1) | JPH08508546A (fr) |
CN (1) | CN1120358A (fr) |
AU (1) | AU672501B2 (fr) |
BR (1) | BR9406105A (fr) |
CA (1) | CA2160123A1 (fr) |
FI (1) | FI954766A0 (fr) |
NO (1) | NO953993D0 (fr) |
NZ (1) | NZ263264A (fr) |
SE (1) | SE9301161L (fr) |
WO (1) | WO1994023122A1 (fr) |
ZA (1) | ZA941235B (fr) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE9301160L (sv) * | 1992-08-28 | 1994-03-01 | Sunds Defibrator Ind Ab | Förfarande för behandling av processvatten |
SE504424C2 (sv) * | 1994-11-04 | 1997-02-10 | Kvaerner Pulping Tech | Sätt att fälla ut övergångsmetaller och alkaliska jordartsmetaller ur blekeriavlutar genom att tillsätta alkalisk vätska |
US5792315A (en) * | 1995-02-27 | 1998-08-11 | Eka Chemicals Ab | Purifying aqueous effluent from a pulp mill using electro chemical membrane device |
SE9500732L (sv) * | 1995-02-27 | 1996-08-28 | Eka Chemicals Ab | Förfarande för behandling av vätskor |
SE9803384L (sv) * | 1998-03-02 | 1999-09-03 | Kemira Kemi Ab | Förfarande för behandling av processvatten |
SG172284A1 (en) * | 2008-12-19 | 2011-07-28 | Xyleco Inc | Processing biomass |
US20100263813A1 (en) * | 2009-04-21 | 2010-10-21 | Andritz Inc. | Green liquor pretreatment of lignocellulosic material |
WO2013040747A1 (fr) * | 2011-09-19 | 2013-03-28 | 北京沃特玛德环境技术股份有限公司 | Procédé d'utilisation complète d'un déchet solide pendant la récupération de soude dans l'industrie de fabrication du papier |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4684472A (en) * | 1985-12-26 | 1987-08-04 | Phillips Petroleum Company | Precipitation of waste chromium compounds utilizing an aqueous sulfide solution |
DE58902905D1 (de) * | 1989-04-28 | 1993-01-14 | Siemens Ag | Verfahren zum entfernen von kupfer aus abwasser. |
US5120448A (en) * | 1990-09-19 | 1992-06-09 | Dorica Josesph G | Removal of aox frm bleach plant mill effluents by ph shift using the alkalinity/acidity sources available at the mill |
EP0564443A1 (fr) * | 1992-03-15 | 1993-10-06 | Kamyr, Inc. | Traitement d'éffluents de blanchiment |
-
1993
- 1993-04-07 SE SE9301161A patent/SE9301161L/ not_active Application Discontinuation
-
1994
- 1994-02-17 JP JP6521969A patent/JPH08508546A/ja active Pending
- 1994-02-17 BR BR9406105A patent/BR9406105A/pt not_active Application Discontinuation
- 1994-02-17 CA CA002160123A patent/CA2160123A1/fr not_active Abandoned
- 1994-02-17 EP EP94911328A patent/EP0693144A1/fr not_active Ceased
- 1994-02-17 NZ NZ263264A patent/NZ263264A/en unknown
- 1994-02-17 AU AU63876/94A patent/AU672501B2/en not_active Ceased
- 1994-02-17 CN CN94191676A patent/CN1120358A/zh active Pending
- 1994-02-17 WO PCT/SE1994/000130 patent/WO1994023122A1/fr not_active Application Discontinuation
- 1994-02-23 ZA ZA941235A patent/ZA941235B/xx unknown
-
1995
- 1995-10-06 FI FI954766A patent/FI954766A0/fi unknown
- 1995-10-06 NO NO953993A patent/NO953993D0/no unknown
Non-Patent Citations (1)
Title |
---|
See references of WO9423122A1 * |
Also Published As
Publication number | Publication date |
---|---|
FI954766A (fi) | 1995-10-06 |
BR9406105A (pt) | 1995-12-12 |
ZA941235B (en) | 1994-09-20 |
WO1994023122A1 (fr) | 1994-10-13 |
AU6387694A (en) | 1994-10-24 |
SE9301161L (sv) | 1994-10-08 |
JPH08508546A (ja) | 1996-09-10 |
NO953993L (no) | 1995-10-06 |
AU672501B2 (en) | 1996-10-03 |
NZ263264A (en) | 1996-08-27 |
CA2160123A1 (fr) | 1994-10-13 |
SE9301161D0 (sv) | 1993-04-07 |
FI954766A0 (fi) | 1995-10-06 |
NO953993D0 (no) | 1995-10-06 |
CN1120358A (zh) | 1996-04-10 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19950909 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT DE ES FR PT SE |
|
17Q | First examination report despatched |
Effective date: 19960805 |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: SUNDS DEFIBRATOR INDUSTRIES AB |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 19980323 |