EP1718801B1 - Method for reducing the extractives content of high-yield pulps and method for producing bleached high-yield pulps - Google Patents
Method for reducing the extractives content of high-yield pulps and method for producing bleached high-yield pulps Download PDFInfo
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- EP1718801B1 EP1718801B1 EP05717239A EP05717239A EP1718801B1 EP 1718801 B1 EP1718801 B1 EP 1718801B1 EP 05717239 A EP05717239 A EP 05717239A EP 05717239 A EP05717239 A EP 05717239A EP 1718801 B1 EP1718801 B1 EP 1718801B1
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- EP
- European Patent Office
- Prior art keywords
- pulp
- surfactant
- peroxide bleaching
- bleaching
- extractives
- 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.)
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 5
- 238000004061 bleaching Methods 0.000 claims abstract description 77
- 150000002978 peroxides Chemical class 0.000 claims abstract description 48
- 239000003381 stabilizer Substances 0.000 claims abstract description 40
- 239000004094 surface-active agent Substances 0.000 claims abstract description 32
- 238000005406 washing Methods 0.000 claims abstract description 13
- 239000008346 aqueous phase Substances 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 239000002253 acid Substances 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 13
- 238000010790 dilution Methods 0.000 claims description 12
- 239000012895 dilution Substances 0.000 claims description 12
- 150000003839 salts Chemical class 0.000 claims description 12
- 229920000642 polymer Polymers 0.000 claims description 9
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 8
- 229920001577 copolymer Polymers 0.000 claims description 8
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 7
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 7
- 150000002191 fatty alcohols Chemical class 0.000 claims description 6
- 229920001519 homopolymer Polymers 0.000 claims description 6
- 239000002736 nonionic surfactant Substances 0.000 claims description 6
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 5
- -1 alkyl phenol Chemical compound 0.000 claims description 5
- 239000003945 anionic surfactant Substances 0.000 claims description 5
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 claims description 5
- 239000011976 maleic acid Substances 0.000 claims description 5
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 claims description 5
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 claims description 5
- 150000001991 dicarboxylic acids Chemical class 0.000 claims description 4
- 229920001732 Lignosulfonate Polymers 0.000 claims description 3
- 239000004117 Lignosulphonate Substances 0.000 claims description 3
- 239000003995 emulsifying agent Substances 0.000 claims description 3
- 235000019357 lignosulphonate Nutrition 0.000 claims description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- 229920001131 Pulp (paper) Polymers 0.000 description 8
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 8
- 235000019353 potassium silicate Nutrition 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000000706 filtrate Substances 0.000 description 6
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 5
- 150000007513 acids Chemical class 0.000 description 5
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical group [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 4
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 239000000654 additive Substances 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 241000183024 Populus tremula Species 0.000 description 3
- 125000000129 anionic group Chemical group 0.000 description 3
- 239000007844 bleaching agent Substances 0.000 description 3
- 239000002738 chelating agent Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 235000014113 dietary fatty acids Nutrition 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000000194 fatty acid Substances 0.000 description 3
- 229930195729 fatty acid Natural products 0.000 description 3
- 150000004665 fatty acids Chemical class 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 159000000000 sodium salts Chemical class 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 150000003505 terpenes Chemical class 0.000 description 3
- 235000007586 terpenes Nutrition 0.000 description 3
- 239000002023 wood Substances 0.000 description 3
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 229930182558 Sterol Natural products 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000007859 condensation product Substances 0.000 description 2
- NFDRPXJGHKJRLJ-UHFFFAOYSA-N edtmp Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CCN(CP(O)(O)=O)CP(O)(O)=O NFDRPXJGHKJRLJ-UHFFFAOYSA-N 0.000 description 2
- 239000002657 fibrous material Substances 0.000 description 2
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 2
- 235000019341 magnesium sulphate Nutrition 0.000 description 2
- 150000002989 phenols Chemical class 0.000 description 2
- 229940068065 phytosterols Drugs 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 150000003432 sterols Chemical class 0.000 description 2
- 235000003702 sterols Nutrition 0.000 description 2
- 239000004753 textile Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 102100031260 Acyl-coenzyme A thioesterase THEM4 Human genes 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- 101000638510 Homo sapiens Acyl-coenzyme A thioesterase THEM4 Proteins 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 241000218657 Picea Species 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- YDONNITUKPKTIG-UHFFFAOYSA-N [Nitrilotris(methylene)]trisphosphonic acid Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CP(O)(O)=O YDONNITUKPKTIG-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 244000052616 bacterial pathogen Species 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 125000003636 chemical group Chemical group 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- DUYCTCQXNHFCSJ-UHFFFAOYSA-N dtpmp Chemical compound OP(=O)(O)CN(CP(O)(O)=O)CCN(CP(O)(=O)O)CCN(CP(O)(O)=O)CP(O)(O)=O DUYCTCQXNHFCSJ-UHFFFAOYSA-N 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 159000000011 group IA salts Chemical class 0.000 description 1
- 239000011121 hardwood Substances 0.000 description 1
- 150000002500 ions Chemical group 0.000 description 1
- 229930013686 lignan Natural products 0.000 description 1
- 150000005692 lignans Chemical class 0.000 description 1
- 235000009408 lignans Nutrition 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 239000010813 municipal solid waste Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000001451 organic peroxides Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 150000003009 phosphonic acids Chemical class 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920005646 polycarboxylate Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000013055 pulp slurry Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001226 reprecipitation Methods 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- RPACBEVZENYWOL-XFULWGLBSA-M sodium;(2r)-2-[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylate Chemical compound [Na+].C=1C=C(Cl)C=CC=1OCCCCCC[C@]1(C(=O)[O-])CO1 RPACBEVZENYWOL-XFULWGLBSA-M 0.000 description 1
- 239000011122 softwood Substances 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 150000003626 triacylglycerols Chemical class 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
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
- D21C9/08—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching
-
- 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
-
- 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 reducing the extractives content of high-yield mechanical pulps.
- the invention also relates to a method for producing bleached high-yield pulps having a reduced content of extractives.
- Extractives are known constituents of wood and pulp species that are extractable with organic solvents.
- the most predominant chemical groups found in extractives are fatty and resin acids, terpenes, phytosterols and phenolic compounds. Extractives are found esterified, glycosylated and nonderivatized.
- the most problematic extractives in wood are mainly the oleophilic compounds. They are fatty acids, resin acids, terpenes and sterols and their function is to protect the tree by preventing attacks from germs, funguses etc. Scandinavian softwoods contain approximately 1.5% extractives by weight while hardwoods of the temperate zone usually contain 2-2.5% by weight.
- the problematic extractives are commonly referred to as pitch. Problems are usually found in high shear force areas and when the temperature, pH or pitch concentration changes.
- a modem bleaching process for mechanical pulps includes often high-consistency peroxide bleaching (PHC). After peroxide bleaching the pulp is often diluted with white water coming from the paper machine and after that the pulp slurry is dewatered. This washing step reduces carry-over of anionic trash to paper machine and also allows recirculation of residual peroxide. Alkaline peroxide oxidizes and removes quite efficiently extractives from the pulp. However, if the pulp in the bottom of PHC bleach tower or after PCH bleaching is diluted with white water the extractives can re-precipitate in the surface of pulp or process equipment due to lower pH of the water, high hardness or electrolyte (salt) concentration.
- PHC high-consistency peroxide bleaching
- Precipitated extractives will be transferred in the fiber surface to the paper machine leading to problems in wet end and paper quality.
- the extractives possibly found in the wash filtrate, can be precipiteted in the process equipment or fibers in acidic or neutral environment.
- US 4 363 699 describes a process for stabilizing alkaline solutions of peroxidic compounds used for bleaching wherein an alkaline salt of a poly-alfa-hydroxyacrylic acid is added to the solution as a stabilizer.
- the stabilized solutions can be used for the bleaching of paper pulps and textiles.
- the bleaching solution may contain a wetting agent which is a surface active agent.
- US 4 963 157 describes a method of bleaching a cellulosic fiber material, especially cotton with hydrogen peroxide.
- the method comprises impregnating the fiber material with a bleaching solution containing hydrogen peroxide and a stabilizer.
- the stabilizer comprises poly-alfa-hydroxyacrylic acid or a salt thereof or the polylactone corresponding thereto, and an organic phosphonic acid or a salt thereof.
- DE 3423452 discloses a solution for avoiding the use of water glass comprising a stabilizing mixture of a poly-alfa-hydroxyacrylic acid (PHAA) and a water soluble homopolymer of acrylic or methacrylic acid or a copolymer of acrylic acid and/or maleic acid.
- the salts, especially the sodium salt of PHAA and the sodium salt of the polycarboxylate polymer are mixed together. Chelating agents can be added to the mixture and thus an improved stabilizer mixture for bleaching processes is obtained.
- the bleaching process is carried out by using an alkaline peroxide bleaching liquor containing said stabilizing mixture.
- the invention is based on the fact that the extractives are more soluble in alkaline conditions and thus, when the pulp is diluted with dilution water, for example white water after bleaching, the extractives may redeposit on the fiber surfaces especially when the pH of dilution water is lower that that of pulp coming out from bleaching tower.
- dilution water for example white water after bleaching
- certain surface-active agents can inhibit precipitation of extractives and thus keep them in water phase.
- the extractives can be washed off the pulp at next dewatering press which in turn leads to reduced extractives content in the pulp. Since the extractives are dispersed and the particles are stabilized, there is no re-precipitation of extractives when the filtrate is re-circulated to the earlier process stages.
- the invention is especially advantageous when the pulp is bleached without silicate as stabilizer, since it has been noticed that silica has some dispersing efficiency against extractives. However, the invention works also well in the presence of silicate.
- a method for reducing the content of extractives of a high-yield pulp in a peroxide bleaching stage comprising contacting the pulp in the peroxide bleaching with an organic stabilizer and in or after the peroxide bleaching with a surfactant, and thereafter subjecting-the bleached pulp to said dewatering or washing for removing extractives along with the aqueous phase.
- the peroxide bleaching stage includes peroxide bleaching of the pulp, optionally dilution of the pulp, and dewatering or washing of the pulp.
- a method for producing bleached high-yield pulp having a reduced content of extractives comprising bleaching high-yield pulp with peroxide, the pulp being contacted with an organic stabilizer during the peroxide bleaching and with a surfactant during the peroxide bleaching or after the peroxide bleaching, and dewatering or washing the bleached pulp for removing extractives along with the aqueous phase and for producing bleached high-yield pulp having a reduced content of extractives.
- the extractives to be removed from the pulp according to the present invention originate from the wood pitch.
- the extractives include fatty acids, resin acids, terpenes, phytosterols and phenolic compounds in esterified, glycosylated and/or nonderivatized form.
- the most problematic extractives include fatty acids, resin acids, triglycerides, steryl esters, sterols and lignans.
- the organic stabilizer and the surfactant can be added separately or these chemicals can be mixed beforehand with the bleaching solution. Furthermore the organic stabilizer and the surfactant can be added simultaneously or separately as one chemical mixture, i.e. product.
- the organic stabilizer and the surfactant can be added to the pulp in the peroxide bleaching or before the peroxide bleaching.
- the surfactant can be added to the pulp after the peroxide bleaching.
- the surfactant can be added to dilution water which is added to the pulp between the peroxide bleaching and the dewatering or washing.
- the dilution water can be white water circulated from the paper machine.
- the organic peroxide stabilizer used in the methods of the invention is preferably a polymeric stabilizer, such as a poly-alfa-hydroxyacrylic acid or a salt thereof or the corresponding polylactone, a homopolymer of acrylic acid, methacrylic acid or maleic acid or a copolymer of acrylic acid and/or methacrylic acid with an unsaturated dicarboxylic acid.
- the polymeric stabilizer can also be a mixture of the poly-alfa-hydroxyacrylic acid and the homopolymer and/or the copolymer.
- the unsaturated dicarboxylic acid is preferably maleic acid.
- the salt of the poly-alfa-hydroxyacrylic acid is preferably a sodium, potassium or ammonium salt.
- the poly-alfa-hydroxyacrylic acid can have a molecular weight of at least 5000, preferably at least 10000, and more preferably at least 15000 (calculated as the sodium salt of the PHAA).
- the homopolymer and the copolymer can have a molecular weight of at least 4000, preferably at least 10000, and more preferably at least 20000.
- the organic stabilizer can also be a phosphonic acid or a salt thereof.
- the salt is preferably a sodium, potassium or ammonium salt.
- Suitable phosphonic acids are for example the (poly)aminophosphonic acids, such as aminotri(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid), i.e. EDTMPA, or diethylenetriaminepenta(methylenephosphonic acid), i.e. DTPMPA.
- This other stabilizer can be an alkaline earth metal compound such as a magnesium and/or calcium compound.
- the alkaline earth metal compound can be in the form of a salt, such as a sulphate, chloride or any other water soluble salt or in the form of a complex with a polymer or a chelating agent.
- a preferred alkaline earth metal salt is magnesium sulphate.
- the amount of the organic stabilizer is preferably from 0.1 kg to 5 kg per ton dry pulp, more preferably from 0.25 kg to 3 kg per ton dry pulp, and even more preferably from 0.5 kg to 3 kg per ton dry pulp.
- the surfactant used in the methods of the invention can be an anionic surfactant, such as naphthalene sulphonate or lignosulphonate, or a non-ionic surfactant, such as an O/W emulsifier, f. ex. a fatty alcohol ethoxylate or alkyl phenol ethoxylate.
- anionic surfactant such as naphthalene sulphonate or lignosulphonate
- a non-ionic surfactant such as an O/W emulsifier, f. ex. a fatty alcohol ethoxylate or alkyl phenol ethoxylate.
- Defoamers can be used in combination with the surfactant(s) to prevent foaming.
- the amount of the surfactant is preferably from 0.005 kg to 2 kg per ton dry pulp, more preferably from 0.05 kg to 1 kg per ton dry pulp.
- the methods of the invention are used in bleaching high-yield mechanical pulps, like groundwood pulps, stone groundwood pulps, pressure groundwood pulps (GW, SGW, PGW), refiner mechanical pulps (RMP), thermomechanical pulps (TMP) and chemithermomechanical pulps (CTMP, APMP).
- high-yield mechanical pulps like groundwood pulps, stone groundwood pulps, pressure groundwood pulps (GW, SGW, PGW), refiner mechanical pulps (RMP), thermomechanical pulps (TMP) and chemithermomechanical pulps (CTMP, APMP).
- peroxide bleaching hydrogen peroxide is preferably used as the bleaching agent.
- Other chemicals such as bleaching stabilizers, chelating agents and/or magnesium sulphate can be used in the bleaching.
- Especially advantageous is to add the chemicals before bleaching or at the same time with bleaching chemicals. If there are several bleaching stages, the chemicals can be added in any of them or in several stages.
- the residence time in the bleaching can vary within a wide range, from 30 to 240 minutes, preferably from 45 to 180 minutes and most preferably from 60 to 120 minutes.
- the residence time will also depend on the temperature used in the bleaching.
- the bleaching of high-yield pulps can be carried out at a temperature of 30-90°C, preferably at a temperature of 50-90°C.
- the bleaching can be carried out at a consistency of choice, but it is most preferably to carry out the bleaching at a high consistency, i.e. about 30% or higher.
- Bleaching can also be carried in two stages with a dewatering stage between the stages.
- the pH in the alkaline bleaching of the invention can be from 7 to 14, preferably from 8 to 11.
- the ratio between the alkali, typically sodium hydroxide, and hydrogen peroxide can vary in a wide range, depending on raw materials and degree of bleaching. Also alternative alkali sources, like sodium carbonate, can be utilized.
- TMP pulp spruce
- PHAA poly- ⁇ -hydroxy acrylate
- CTMP-pulp (aspen) was taken from a mill and bleached with peroxide to brightness of 83-84% ISO.
- the pulp was already chelated in the mill and the manganese content was 1.5 ppm, Fe 5 ppm.
- the additives were dosed in the peroxide bleaching stage and after bleaching the pulp was diluted to 10% consistency at different pH levels, and subsequently dewatered.
- the table below shows the turbidity of the filtrate after dewatering.
- the experiment according to this invention was done using per ton dry pulp 2 kg polymer (poly- ⁇ -hydroxy acrylate) as stabilizer and 0.1 kg naphthalene sulphonate + 0.1 kg non-ionic surfactant (fatty alcohol ethoxylate 7 mole EO, C12-C14, HLB 12.3).
- polymer poly- ⁇ -hydroxy acrylate
- non-ionic surfactant fatty alcohol ethoxylate 7 mole EO, C12-C14, HLB 12.3
- waterglass and poly- ⁇ -hydroxy acrylate were used as stabilizers.
- the bleaching result and chemicals consumption was about the same in each case.
- silica originating from the waterglass increases turbidity. This may be attributed to higher extractives content in the filtrate.
- silicate is replaced by a polymer-based stabilizer, turbidity is lower and thus extractives content in pulp is higher.
- the chemical composition according to this invention yields higher turbidity, which proves that the extractives dissolved in alkaline peroxide are not re-precipitated after dilution.
- CTMP-pulp A sample of CTMP-pulp (aspen) was taken from a mill and bleached with peroxide in high consistency. The bleaching conditions and results are shown in the table below.
- the surfactants were added in the bleaching stage, and after bleaching the pulp was diluted with ion-exchanged water.
- the composition of the surfactants here was naphtalene sulfonic acid condensation product (Na-salt) and fatty-alcohol ethoxylate (same as in previous example) in weight-ratio 2:1 (dosage as 20% water solution).
- the polymer-based stabilizer was a mixture of poly-alfa-hydroxyacrylate and maleate-acrylate copolymer (1:4 w:w) having a active substance content of 25%.
- DCM stands for dichloromethane
- CTMP-pulp A sample of CTMP-pulp (aspen) was taken from a mill and bleached with peroxide to brightness on 83-84% ISO.
- the surfactant additives were dosed in peroxide bleaching stage and after bleaching the pulp was diluted to 10% consistency at different pH levels, and subsequently dewatered. In one experiment a surfactant additive was also dosed after the dilution. The results are shown in the table below.
- the surfactant additives used here were naphtalenesulphonate condensation product ( A ) and fatty alcohol ethoxylate ( B , 25 mole EO, C16-C18, HLB 16).
- the polymer-based stabilizer was a mixture of poly-alfa-hydroxyacrylate and maleate-acrylate copolymer (1:4 w:w) having a active substance content of 25%.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Steroid Compounds (AREA)
- Extraction Or Liquid Replacement (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20040282A FI121385B (fi) | 2004-02-24 | 2004-02-24 | Menetelmä suursaantomassojen uuteainepitoisuuden vähentämiseksi ja menetelmä valkaistujen suursaantomassojen valmistamiseksi |
PCT/FI2005/000112 WO2005080672A2 (en) | 2004-02-24 | 2005-02-23 | Method for reducing the extractives content of high-yield pulps and method for producing bleached high-yield pulps |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1718801A2 EP1718801A2 (en) | 2006-11-08 |
EP1718801B1 true EP1718801B1 (en) | 2007-10-17 |
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ID=31725758
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP05717239A Active EP1718801B1 (en) | 2004-02-24 | 2005-02-23 | Method for reducing the extractives content of high-yield pulps and method for producing bleached high-yield pulps |
Country Status (9)
Country | Link |
---|---|
US (1) | US20070272378A1 (fi) |
EP (1) | EP1718801B1 (fi) |
CN (1) | CN100591842C (fi) |
AT (1) | ATE376094T1 (fi) |
BR (1) | BRPI0507851A (fi) |
CA (1) | CA2553662C (fi) |
DE (1) | DE602005002933T2 (fi) |
FI (1) | FI121385B (fi) |
WO (1) | WO2005080672A2 (fi) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
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FI20070126A0 (fi) | 2006-09-08 | 2007-02-13 | Linde Ag | Menetelmä hartsin poistamiseksi massasta ja hiilidioksidin tai (bi)karbonaatin käyttö tähän tarkoitukseen |
WO2013178875A1 (en) * | 2012-05-29 | 2013-12-05 | Kemira Oyj | A process for the treatment of fibre material and a new composition |
TW201610265A (zh) | 2014-05-20 | 2016-03-16 | 喬治亞太平洋消費者產品公司 | 非木材纖維之漂白及植物性雜質減量方法 |
TW201544652A (zh) * | 2014-05-20 | 2015-12-01 | Georgia Pacific Consumer Prod | 非木材纖維之漂白及植物性雜質減量方法 |
TW201610261A (zh) | 2014-05-20 | 2016-03-16 | 喬治亞太平洋消費者產品公司 | 非木材纖維之漂白及植物性雜質減量方法 |
WO2019051013A1 (en) | 2017-09-11 | 2019-03-14 | Solenis Technologies, L.P. | METHOD FOR IMPROVING OXYGEN DELIGNIFICATION OF WOOD CHEMICAL PULPES |
US20210355634A1 (en) * | 2018-11-07 | 2021-11-18 | Kemira Oyj | A composition for use as peroxide stabilizer |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
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LU74434A1 (fi) * | 1976-02-25 | 1977-09-12 | ||
DE3423452A1 (de) * | 1984-06-26 | 1986-01-02 | Sandoz-Patent-GmbH, 7850 Lörrach | Stabilisierende mischung zur peroxidbleiche zellulosehaltiger materialien |
US4963157A (en) * | 1987-04-17 | 1990-10-16 | Nippon Peroxide Co., Ltd. | Method for bleaching cellulosic fiber material with hydrogen peroxide |
US5234544A (en) * | 1989-10-18 | 1993-08-10 | Air Products And Chemicals, Inc. | Cleaning and bleaching of secondary fiber |
JP3191828B2 (ja) * | 1992-05-27 | 2001-07-23 | 三菱瓦斯化学株式会社 | 印刷古紙の脱墨漂白方法 |
DE4344029A1 (de) * | 1993-12-23 | 1995-06-29 | Grillo Werke Ag | Copolymerisate ungesättigter Carbonsäuren, Verfahren zur Herstellung und ihre Verwendung |
CN1088484C (zh) * | 1999-06-15 | 2002-07-31 | 杭州市化工研究所 | 造纸用树脂障碍控制剂 |
AU2001245969B2 (en) * | 2000-03-23 | 2004-10-28 | Solenis Technologies Cayman, L.P. | Pitch and stickies control in pulp and papermaking processes |
-
2004
- 2004-02-24 FI FI20040282A patent/FI121385B/fi active IP Right Grant
-
2005
- 2005-02-23 AT AT05717239T patent/ATE376094T1/de not_active IP Right Cessation
- 2005-02-23 EP EP05717239A patent/EP1718801B1/en active Active
- 2005-02-23 CN CN200580005933A patent/CN100591842C/zh active Active
- 2005-02-23 DE DE602005002933T patent/DE602005002933T2/de active Active
- 2005-02-23 US US10/590,297 patent/US20070272378A1/en not_active Abandoned
- 2005-02-23 WO PCT/FI2005/000112 patent/WO2005080672A2/en active IP Right Grant
- 2005-02-23 BR BRPI0507851-2A patent/BRPI0507851A/pt not_active IP Right Cessation
- 2005-02-23 CA CA2553662A patent/CA2553662C/en active Active
Also Published As
Publication number | Publication date |
---|---|
FI121385B (fi) | 2010-10-29 |
BRPI0507851A (pt) | 2007-07-10 |
WO2005080672A3 (en) | 2005-12-08 |
US20070272378A1 (en) | 2007-11-29 |
CA2553662C (en) | 2012-10-23 |
ATE376094T1 (de) | 2007-11-15 |
CN1922359A (zh) | 2007-02-28 |
CA2553662A1 (en) | 2005-09-01 |
FI20040282A0 (fi) | 2004-02-24 |
FI20040282A (fi) | 2005-08-25 |
EP1718801A2 (en) | 2006-11-08 |
DE602005002933D1 (de) | 2007-11-29 |
CN100591842C (zh) | 2010-02-24 |
DE602005002933T2 (de) | 2008-07-24 |
WO2005080672A2 (en) | 2005-09-01 |
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