EP0226114B1 - Procédé de blanchiment et délignification de produits cellulosiques - Google Patents
Procédé de blanchiment et délignification de produits cellulosiques Download PDFInfo
- Publication number
- EP0226114B1 EP0226114B1 EP86116722A EP86116722A EP0226114B1 EP 0226114 B1 EP0226114 B1 EP 0226114B1 EP 86116722 A EP86116722 A EP 86116722A EP 86116722 A EP86116722 A EP 86116722A EP 0226114 B1 EP0226114 B1 EP 0226114B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cyanamide
- process according
- bleaching
- pulp
- cellulose
- 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
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
- D21C9/1036—Use of compounds accelerating or improving the efficiency of the processes
Definitions
- the present invention relates to a method for bleaching and delignifying pulp-containing products such as Pulp, wood pulp, wood yield pulp and semi-pulp with peroxides and / or oxygen and / or ozone as bleach.
- cellulose from wood, reeds, straw, bagasse, etc. these raw materials are subjected to a digestion process (sulfite or sulfate process). After digestion or grinding, the pulp is processed by washing and bleaching.
- the main purpose of bleaching is to lighten the color of the pulp and to remove a large part of the lignin that is still present.
- Standard bleaching generally consists of three stages, with the first stage being chlorination of the residual lignin with chlorine water or chlorine gas at pH 1-2. In the second stage the chlorine lignins are then washed out with water or sodium hydroxide solution, while in the third stage the pulp is subjected to an oxidizing and brightening bleaching with hypochlorite at pH> 6.
- the particularly gentle, but expensive bleach with chlorine dioxide can either be added to the standard bleach or replace the hypochlorite treatment.
- a disadvantage of these processes is the high environmental impact, which is caused above all by the chlorination, because a large amount of chlorine lignins are produced here, which represent a high pollution of wastewater.
- a much more environmentally friendly method is bleaching with peroxides (such as sodium peroxide or hydrogen peroxide) or oxygen or oxon.
- peroxides such as sodium peroxide or hydrogen peroxide
- oxygen or oxon peroxide bleaching
- Peroxide bleaching like chlorine dioxide treatment, is used in addition to standard bleaching levels to produce very white pulps.
- these compounds can also be used as sole bleaching agents, particularly in the case of semi-bleaching.
- a disadvantage of these processes is the limited bleaching effect of the peroxides or oxygen, so that the quality of a highly bleached pulp cannot be achieved economically. This is one of the main reasons why these bleaching processes have not yet become widespread.
- FR-A-2 560 898 a method for digesting wood waste from industry and agriculture using peroxide and cyanamide is known.
- Raw cellulose which is in a crystalline form, is broken down by an alkaline oxidizing treatment under extremely drastic conditions in such a way that it can be digested by microorganisms. In this way, however, no bleached delignified pulp is obtained, but rather a cellulose which is at least partially broken down in such a way that it can be used as feed for ruminants.
- a method for activating peroxide-based bleaching agents is known, according to which a bleaching composition is obtained which consists of a bleaching agent, a buffer and cyanamide and which is suitable for bleaching fabrics in household washing machines at temperatures of 15 up to 70 ° C.
- the present invention was therefore based on the object of developing a method for bleaching and delignifying cellulose-containing products with peroxides and / or oxygen and / or ozone, which does not have the disadvantages of the prior art mentioned, but which, despite good environmental compatibility, has an excellent bleaching effect .
- This object was achieved according to the invention by additionally using 0.01 to 2.5% by weight of cyanamide and / or cyanamide salts, based on the dry weight of the pulp, and adjusting the pH of the bleach to 4 to 13.
- hydrogen peroxide or sodium peroxide is used in an amount of 1 to 2.5% by weight, based on the dry matter content of the pulp, the H 2 0 2 preferably in a 30 to 35% aqueous solution is used.
- the amount of cyanamide or cyanamide salt used according to the invention depends essentially on the peroxide or oxygen or ozone content and is 0.01 to 2.5% by weight, preferably 0.1 to 1.0% by weight. , based on the dry matter content of the pulp.
- Cyanamide itself can be used both as a solid and as an aqueous solution (for example in the form of a 10 to 60% strength aqueous solution).
- the alkaline salts such as sodium hydrogen cyanamide, calcium cyanamide or magnesium cyanamide are preferably used as cyanamide salts, because a certain alkaline pH value adjustment can be carried out at the same time.
- the alkaline earth ions calcium and magnesium simultaneously have a stabilizing effect on the H 2 0 2 solution, as will be explained in more detail below.
- Decomposition of the peroxide during the bleaching process is highly undesirable, since not only is the bleaching effect reduced, but at the same time there is also noticeable damage to the cellulose fiber.
- stabilizers such as e.g. Water glass or complexing agents such as Na-EDTA in an amount of 0.1 to 5 wt .-%, based on the dry content of the pulp.
- such an addition can generally be dispensed with if the heavy metal salts are removed by washing the pulp before bleaching.
- the cellulose suspension can also be mixed with metal salts, which in addition to the stabilizing effect also have an activating effect on the peroxide.
- metal salts which in addition to the stabilizing effect also have an activating effect on the peroxide.
- amounts of 0.1 to 5% by weight, based on the dry weight of the pulp are recommended.
- the aluminum salts or alkaline earth metal salts such as magnesium, calcium and barium salts are preferred as the metal salts, while the oxides, hydroxides, sulfates, chlorides and nitrates are particularly suitable as anions due to their low cost.
- the optimum pH is 4.0 to 13.0, preferably 5.0 to 10.0, and that temperatures of 20 ° C. to 150 ° C. are to be regarded as preferred. In these conditions, the best results are generally high degree of whiteness possible with a relatively short treatment time and under gentle conditions, whereby the exact process parameters depend on the type and pretreatment of the pulp used.
- the pulp suspension which generally has a solids content of 3 to 20% by weight, is adjusted to the desired pH with the customary acidic or basic reacting substances, and the stabilizers or activators such as water glass or metal salts are then added . The peroxide or oxygen or ozone and cyanamide are then added. After bleaching at a certain temperature, which takes between 15 minutes and 4 hours, depending on the type of whiteness desired, the pulp is worked up. For this purpose, the pulp suspension is adjusted to a pH of 5 to 7 and then the pulp is dewatered or dried.
- the degree of delignification which is defined by the kappa value (see examples), is about 50% cheaper for peroxide or oxygen bleaching with cyanamide than for bleaching without cyanamide.
- the viscosity which is a measure of the degree of polymerization of the cellulose and thus a direct indication of the damage (decomposition) of the cellulose fiber, is significantly better in the process according to the invention than in the processes according to the prior art.
- the method according to the invention can in principle apply to all cellulose-containing products such as Sulfite or sulfate pulp, CTMP pulp, needle pulp or wood pulp and can be used in all bleaching stages such as pre-bleaching or post-bleaching. It is also possible to combine different bleaching levels, e.g. Peroxide and chlorine dioxide bleach if this appears beneficial for any reason.
- cyanamide in the examples are given in% by weight and, unless stated otherwise, relate to the dry content of the pulp.
- Example 2 The procedure was as in Example 1 but was carried out after the hydrogen peroxide addition another addition of 20 mg of cyanamide in the form of 0.2 g of a 10% cyanamide solution ( ⁇ -_ 0.2 wt .-% based on the dry content of the Pulp).
- Example 1 The procedure is as in Example 4, but 0.5 g of a 10% strength aqueous cyanamide solution (0.5% by weight) were added after the H 2 O 2 addition. Refurbishment see Example 1.
- Example 6 The procedure is as in Example 6, but with the addition of 4.0 g of a 10% strength aqueous cyanamide solution (1% by weight).
- Example 10 The procedure is as in Example 10, but with the addition of 0.5 g of a 10% aqueous cyanamide solution.
- Example 12 The procedure was as in Example 12, but with the addition of 0.5 g of a 10% cyanamide solution (0.5% by weight).
- Example 14 The procedure is as in Example 14, but with the addition of 0.5 g of a 10% cyanamide solution.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Cereal-Derived Products (AREA)
- Detergent Compositions (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Breeding Of Plants And Reproduction By Means Of Culturing (AREA)
- Prostheses (AREA)
- Optical Transform (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
- General Preparation And Processing Of Foods (AREA)
- Coloring Foods And Improving Nutritive Qualities (AREA)
Claims (14)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT86116722T ATE54475T1 (de) | 1985-12-16 | 1986-12-02 | Verfahren zur bleiche und delignifizierung von zellstoffhaltigen produkten. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19853544398 DE3544398A1 (de) | 1985-12-16 | 1985-12-16 | Verfahren zur bleiche und delignifizierung von zellstoffhaltigen produkten |
DE3544398 | 1985-12-16 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0226114A1 EP0226114A1 (fr) | 1987-06-24 |
EP0226114B1 true EP0226114B1 (fr) | 1990-07-11 |
Family
ID=6288532
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86116722A Expired - Lifetime EP0226114B1 (fr) | 1985-12-16 | 1986-12-02 | Procédé de blanchiment et délignification de produits cellulosiques |
Country Status (9)
Country | Link |
---|---|
US (1) | US5034096A (fr) |
EP (1) | EP0226114B1 (fr) |
JP (1) | JPH0723593B2 (fr) |
AT (1) | ATE54475T1 (fr) |
CA (1) | CA1277457C (fr) |
DE (2) | DE3544398A1 (fr) |
ES (1) | ES2016084B3 (fr) |
FI (1) | FI85390C (fr) |
NO (1) | NO169023C (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4114135A1 (de) * | 1991-04-30 | 1992-11-05 | Sueddeutsche Kalkstickstoff | Verfahren zur chlorfreien bleiche und delignifizierung von alkalizellstoff |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4004364A1 (de) * | 1990-02-13 | 1991-08-14 | Sueddeutsche Kalkstickstoff | Verfahren zur chlorfreien bleiche und delignifizierung von zellstoff |
DE4031597A1 (de) * | 1990-10-05 | 1992-04-09 | Sueddeutsche Kalkstickstoff | Verfahren zur chlorarmen bleiche und delignifizierung von zellstoff |
US5242464A (en) * | 1991-04-22 | 1993-09-07 | Pyxis Corporation | Method of bleaching wood |
US6398908B1 (en) | 1991-04-30 | 2002-06-04 | Eka Nobel Ab | Process for acid bleaching of lignocellulose-containing pulp with a magnesium compound |
DE4114134A1 (de) * | 1991-04-30 | 1992-11-05 | Sueddeutsche Kalkstickstoff | Verfahren zur chlorfreien bleiche und delignifizierung von alkalizellstoff |
DE4128968A1 (de) * | 1991-08-31 | 1993-03-04 | Genkinger Hebe Foerdertech | Verfahren und vorrichtung zum wechseln eines warenbaums in einer webmaschine |
US5411635A (en) * | 1993-03-22 | 1995-05-02 | The Research Foundation Of State University Of New York | Ozone/peroxymonosulfate process for delignifying a lignocellulosic material |
CA2137450C (fr) * | 1993-04-06 | 2001-07-24 | Jack Kogan | Blanchiment de la pate recyclee a l'ozone et au peroxyde d'hydrogene |
US5620563A (en) * | 1994-10-31 | 1997-04-15 | Pulp Paper Res Inst | Process for delignification and bleaching of chemical wood pulps with hydrogen peroxide and a dicyandiamide activator |
US6302997B1 (en) * | 1999-08-30 | 2001-10-16 | North Carolina State University | Process for producing a pulp suitable for papermaking from nonwood fibrous materials |
US8268122B2 (en) * | 2005-12-02 | 2012-09-18 | Akzo Nobel N.V. | Process of producing high-yield pulp |
AU2006321020B2 (en) * | 2005-12-02 | 2011-02-10 | Akzo Nobel Chemicals International B.V. | Process of producing high-yield pulp |
US20100224336A1 (en) * | 2005-12-14 | 2010-09-09 | University Of Maine System Board Of Trustees | Process of bleaching a wood pulp |
US20070131364A1 (en) * | 2005-12-14 | 2007-06-14 | University Of Maine | Process for treating a cellulose-lignin pulp |
EP2861799B1 (fr) | 2012-06-13 | 2019-06-05 | University of Maine System Board of Trustees | Procédé écoénergétique pour la préparation de fibres de nanocellulose |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE532222C (de) * | 1929-08-30 | 1931-08-29 | Noviston Akt Ges | Verfahren zur Herstellung von Zellstoff durch alkalischen Aufschluss |
US4025453A (en) * | 1976-02-09 | 1977-05-24 | Shell Oil Company | Activated bleaching process and compositions therefor |
US4158595A (en) * | 1977-07-27 | 1979-06-19 | Hercules Incorporated | Preparation of hydrophilic styrene maleic anhydride copolymer fibers for use in papermaking |
US4426466A (en) * | 1982-06-09 | 1984-01-17 | Minnesota Mining And Manufacturing Company | Paper treatment compositions containing fluorochemical carboxylic acid and epoxidic cationic resin |
FR2557605B1 (fr) * | 1983-12-29 | 1987-12-11 | Atochem | Procede de blanchiment de pates papetieres par le peroxyde d'hydrogene |
FR2560898B1 (fr) * | 1984-03-06 | 1988-01-08 | Air Liquide | Procede de destructuration de matieres lignocellulosiques |
-
1985
- 1985-12-16 DE DE19853544398 patent/DE3544398A1/de not_active Ceased
-
1986
- 1986-12-02 DE DE8686116722T patent/DE3672577D1/de not_active Expired - Lifetime
- 1986-12-02 ES ES86116722T patent/ES2016084B3/es not_active Expired - Lifetime
- 1986-12-02 EP EP86116722A patent/EP0226114B1/fr not_active Expired - Lifetime
- 1986-12-02 AT AT86116722T patent/ATE54475T1/de active
- 1986-12-09 US US06/939,562 patent/US5034096A/en not_active Expired - Fee Related
- 1986-12-09 CA CA000524868A patent/CA1277457C/fr not_active Expired - Lifetime
- 1986-12-10 NO NO864983A patent/NO169023C/no unknown
- 1986-12-15 FI FI865100A patent/FI85390C/fi not_active IP Right Cessation
- 1986-12-16 JP JP61297856A patent/JPH0723593B2/ja not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4114135A1 (de) * | 1991-04-30 | 1992-11-05 | Sueddeutsche Kalkstickstoff | Verfahren zur chlorfreien bleiche und delignifizierung von alkalizellstoff |
Also Published As
Publication number | Publication date |
---|---|
FI865100A0 (fi) | 1986-12-15 |
ES2016084B3 (es) | 1990-10-16 |
FI865100A (fi) | 1987-06-17 |
ATE54475T1 (de) | 1990-07-15 |
US5034096A (en) | 1991-07-23 |
FI85390C (fi) | 1992-04-10 |
NO169023C (no) | 1992-04-29 |
JPH0723593B2 (ja) | 1995-03-15 |
DE3672577D1 (de) | 1990-08-16 |
FI85390B (fi) | 1991-12-31 |
EP0226114A1 (fr) | 1987-06-24 |
NO864983D0 (no) | 1986-12-10 |
NO169023B (no) | 1992-01-20 |
JPS62191588A (ja) | 1987-08-21 |
CA1277457C (fr) | 1990-12-11 |
NO864983L (no) | 1987-06-17 |
DE3544398A1 (de) | 1987-06-19 |
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