CN102061638A - Process for catalytically bleaching pulp by acetate/persulfate - Google Patents
Process for catalytically bleaching pulp by acetate/persulfate Download PDFInfo
- Publication number
- CN102061638A CN102061638A CN2010105417696A CN201010541769A CN102061638A CN 102061638 A CN102061638 A CN 102061638A CN 2010105417696 A CN2010105417696 A CN 2010105417696A CN 201010541769 A CN201010541769 A CN 201010541769A CN 102061638 A CN102061638 A CN 102061638A
- Authority
- CN
- China
- Prior art keywords
- bleaching
- pulp
- consumption
- catalytic
- hydrogen peroxide
- 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.)
- Granted
Links
- 238000004061 bleaching Methods 0.000 title claims abstract description 35
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 title claims abstract description 15
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 title claims abstract description 11
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 42
- 230000003197 catalytic effect Effects 0.000 claims abstract description 25
- 238000005516 engineering process Methods 0.000 claims abstract description 16
- 239000003513 alkali Substances 0.000 claims abstract description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000001301 oxygen Substances 0.000 claims abstract description 8
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 8
- 239000007844 bleaching agent Substances 0.000 claims abstract description 5
- 239000002994 raw material Substances 0.000 claims abstract description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 30
- 229920001131 Pulp (paper) Polymers 0.000 claims description 26
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 20
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 claims description 20
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 10
- 239000000460 chlorine Substances 0.000 claims description 10
- 229910052801 chlorine Inorganic materials 0.000 claims description 10
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 10
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 10
- 238000004076 pulp bleaching Methods 0.000 claims description 9
- 238000009897 hydrogen peroxide bleaching Methods 0.000 claims description 7
- 239000004115 Sodium Silicate Substances 0.000 claims description 5
- 235000019795 sodium metasilicate Nutrition 0.000 claims description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 5
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 5
- 239000003054 catalyst Substances 0.000 claims description 4
- 230000002787 reinforcement Effects 0.000 claims description 2
- 230000007613 environmental effect Effects 0.000 abstract description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 abstract 2
- 229910001870 ammonium persulfate Inorganic materials 0.000 abstract 1
- 235000019395 ammonium persulphate Nutrition 0.000 abstract 1
- 239000002351 wastewater Substances 0.000 abstract 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 3
- 239000012190 activator Substances 0.000 description 2
- 229920005610 lignin Polymers 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 102000004190 Enzymes Human genes 0.000 description 1
- 108090000790 Enzymes Proteins 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
Landscapes
- Paper (AREA)
Abstract
The invention discloses a process for catalytically bleaching pulp by acetate/persulfate, relates to an improved process for catalytically bleaching pulp by acetate/persulfate, and belongs to pulp catalytic bleaching technology. The process mainly comprises the following steps of: 1, performing catalytic bleaching pretreatment on the pulp, namely performing conventional catalytic bleaching pretreatment on the pulp in the presence of Cu(CH3COO)2, or Co(CH3COO)2, CH3COOH, (NH4)2S2O8 and by introducing oxygen at normal pressure; and 2, performing subsequent full chlorine-free bleaching, namely performing subsequent two-stage bleaching treatment consisting of a hydrogen dioxide enhanced alkali treatment stage and a hydrogen dioxide bleaching stage on the pulp subjected to catalytic bleaching pretreatment. The full chlorine-free bleaching technology is adopted, raw materials are wide in sources and low in consumption, the process does not have harsh requirement on environmental conditions, various properties of the pulp are obviously improved, the whiteness and strength of the pulp can be improved, bleaching wastewater pollution is eliminated and the consumption of a bleaching agent is reduced.
Description
Technical field
The present invention relates to the technology of a kind of acetate/persulfate catalytic bleaching pulp, is an improved paper pulp catalytically bleaching technology.
Background technology
In recent years because environmental protection and to the requirement of paper products quality, the paper-making pulping industry has turned to and has adopted element-free chlorine (ECF) or completely without chlorine (TCF) bleaching technology.For improving the TCF bleaching efficiency, can adopt biology enzyme preliminary treatment, activator preliminary treatment, bleaching section to add methods such as assistant activator, this respect research at present is comparatively deep.Some composition effect in they and the paper pulp forms delignification or helps the situation of delignification, and improves the bleachability of paper pulp, improves the physical property of paper pulp.Adopt acetate/persulfate system catalytic pretreatment paper pulp, can increase the active group of paper pulp residual lignin, enhancing hydrogen peroxide etc. floats the reaction efficiency of agent and residual lignin, thereby improves the bleachability of paper pulp.But acetate/persulfate catalytic pretreatment section and hydrogen peroxide are formed new for chlorine non-polluting bleachoing technology, have not yet to see relevant technology report.
Summary of the invention
Technical problem to be solved by this invention provides the technology of a kind of improved acetate/persulfate catalytic bleaching pulp, and its technology is implemented easily, and is pollution-free, and the bleachability that improves paper pulp is effective, and it is obvious to improve the every performance of paper pulp.
Solve the scheme that technical problem of the present invention adopts and mainly comprise following steps: 1. to the association with pulp bleaching catalytic pretreatment, at Cu (CH
3COO)
2Or Co (CH
3COO)
2, CH
3COOH, (NH
4)
2S
2O
8Lead under the condition of oxygen with normal pressure, paper pulp is carried out conventional bleach catalyst preliminary treatment; 2. follow-up total chlorine free bleaching is handled via the follow-up second stage bleaching that the alkali treatment section and the hydrogen peroxide bleaching section of hydrogen peroxide reinforcement are formed the pretreated paper pulp of bleach catalyst again.
During to the association with pulp bleaching catalytic pretreatment, the weight percent concentration of paper pulp is 4.0%～6.0%, and the percentage that each raw material accounts for paper pulp weight is Cu (CH
3COO)
2Or Co (CH
3COO)
2Consumption is 0.008%～0.012%, CH
3COOH consumption 15%～25%, normal pressure leads to oxygen, and pretreated temperature is controlled at 60 ℃～80 ℃, time 1.5h～2.5h; During to the association with pulp bleaching catalytic pretreatment, also added (NH
4)
2S
2O
8, (NH
4)
2S
2O
8Consumption and Cu (CH
3COO)
2Or Co (CH
3COO)
2Mol ratio be 2: 1.
The optimum process condition of follow-up total chlorine free bleaching of the present invention is:
1. the alkali treatment section strengthened of hydrogen peroxide, NaOH accounts for the consumption 1.0wt%～2.0wt% of paper pulp, hydrogen peroxide consumption 0.4wt%～0.6wt%, magnesium sulfate consumption 0.08wt%～0.12wt%, diethylene triamine pentacetic acid (DTPA) consumption 0.03wt%～0.07wt%, pulp density 8wt%～12wt% during processing, 65 ℃～75 ℃ of temperature, 0.5 hour～1.5 hours time;
2. hydrogen peroxide bleaching section, NaOH accounts for the consumption 1.0wt%～2.0wt% of paper pulp, magnesium sulfate consumption 0.08wt%～0.12wt%, sodium metasilicate consumption 0.8wt%～1.2wt%, diethylene triamine pentacetic acid (DTPA) consumption 0.08wt%～0.12wt%, hydrogen peroxide consumption 1.8wt%～2.2wt%, pulp density 8wt%～12wt% during processing, 75 ℃～85 ℃ of temperature, 2.0 hours～3.0 hours time.
The invention has the beneficial effects as follows:
(1) raw material is easy to get, and consumption is few, and process implementing is easy;
(2) improve the every performance of paper pulp, adopt acetate/persulfate catalytic pretreatment operation, floating paper pulp becomes paper tensile index 19%, tear index 7%, burst index 24% eventually to improve TCF.Tensile index, tear index and burst index are three key indexs of general paper physical property;
(3) the raising pulp brightness is obvious, adopts acetate/persulfate catalytic pretreatment operation, can improve TCF and float pulp brightness 5.6%ISO eventually;
(4) reduce the bleaching reagent consumption, adopt acetate/persulfate catalytic pretreatment operation, can reduce hydrogen peroxide and consume more than 60%.
(5) overall process adopts complete free from chloride bleaching technology, the pollution-free generation of bleaching process.
The specific embodiment
Embodiment 1
In weight percent concentration is 4.0% paper pulp, Cu (CH
3COO)
2Or Co (CH
3COO)
2Consumption is 0.008%, CH
3The COOH consumption is 15%, the logical oxygen of normal pressure, (NH
4)
2S
2O
8Consumption with Cu (CH
3COO)
2Or Co (CH
3COO)
2Mol ratio be 2: 1, to the association with pulp bleaching catalytic pretreatment, the temperature of processing is controlled at 60 ℃, time 1.5h.Carry out follow-up total chlorine free bleaching then and handle, at the alkali treatment section that hydrogen peroxide is strengthened, sodium hydroxide concentration 1.0%, hydrogen peroxide consumption 0.4%, magnesium sulfate consumption 0.08%, diethylene triamine pentacetic acid (DTPA) consumption 0.03%, pulp density 8% during processing, 65 ℃ of temperature, 0.5 hour time;
In the hydrogen peroxide bleaching section, sodium hydroxide concentration 1.0%, magnesium sulfate consumption 0.08%, sodium metasilicate consumption 0.8%, diethylene triamine pentacetic acid (DTPA) consumption 0.08%, hydrogen peroxide consumption 1.8%, pulp density 8% during processing, 75 ℃ of temperature, 2.0 hours time.
Embodiment 2
In weight percent concentration is 5.0% paper pulp, Cu (CH
3COO)
2Or Co (CH
3COO)
2Consumption is 0.01%, CH
3The COOH consumption is 20%, the logical oxygen of normal pressure, (NH
4)
2S
2O
8Consumption with Cu (CH
3COO)
2Or Co (CH
3COO)
2Mol ratio be 2: 1, to the association with pulp bleaching catalytic pretreatment, the temperature of processing is controlled at 70 ℃, time 2.0h.Carry out follow-up total chlorine free bleaching then and handle, at the alkali treatment section that hydrogen peroxide is strengthened, sodium hydroxide concentration 1.5%, hydrogen peroxide consumption 0.5%, magnesium sulfate consumption 0.1%, diethylene triamine pentacetic acid (DTPA) consumption 0.05%, pulp density 10% during processing, 70 ℃ of temperature, 1.0 hours time;
In the hydrogen peroxide bleaching section, sodium hydroxide concentration 1.5%, magnesium sulfate consumption 0.1%, sodium metasilicate consumption 1.0%, diethylene triamine pentacetic acid (DTPA) consumption 0.1%, hydrogen peroxide consumption 2.0%, pulp density 10% during processing, 80 ℃ of temperature, 2.5 hours time.
Embodiment 3
In weight percent concentration is 6.0% paper pulp, Cu (CH
3COO)
2Or Co (CH
3COO)
2Consumption is 0.012%, CH
3The COOH consumption is 25%, the logical oxygen of normal pressure, (NH
4)
2S
2O
8Consumption with Cu (CH
3COO)
2Or Co (CH
3COO)
2Mol ratio be 2: 1, to the association with pulp bleaching catalytic pretreatment, the temperature of processing is controlled at 80 ℃, time 2.5h.Carry out follow-up total chlorine free bleaching then and handle, at the alkali treatment section that hydrogen peroxide is strengthened, sodium hydroxide concentration 2.0%, hydrogen peroxide consumption 0.6%, magnesium sulfate consumption 0.12%, diethylene triamine pentacetic acid (DTPA) consumption 0.07%, pulp density 12% during processing, 75 ℃ of temperature, 1.5 hours time;
In the hydrogen peroxide bleaching section, sodium hydroxide concentration 2.0%, magnesium sulfate consumption 0.12%, sodium metasilicate consumption 1.2%, diethylene triamine pentacetic acid (DTPA) consumption 0.12%, hydrogen peroxide consumption 2.2%, pulp density 12% during processing, 85 ℃ of temperature, 3.0 hours time.
Claims (4)
1. the technology of acetate/persulfate catalytic bleaching pulp is characterized in that mainly comprising following steps:
1. to the association with pulp bleaching catalytic pretreatment, at Cu (CH
3COO)
2Or Co (CH
3COO)
2, CH
3COOH, (NH
4)
2S
2O
8Lead under the condition of oxygen with normal pressure, paper pulp is carried out conventional bleach catalyst preliminary treatment;
2. follow-up total chlorine free bleaching is handled via the follow-up second stage bleaching that the alkali treatment section and the hydrogen peroxide bleaching section of hydrogen peroxide reinforcement are formed the pretreated paper pulp of bleach catalyst again.
2. by the technology of the described acetate of claim 1/persulfate catalytic bleaching pulp, it is characterized in that: during to the association with pulp bleaching catalytic pretreatment, the weight percent concentration of paper pulp is 4.0%～6.0%, and the percentage that each raw material accounts for paper pulp weight is Cu (CH
3COO)
2Or Co (CH
3COO)
2Consumption is 0.008%～0.012%, CH
3COOH consumption 15%～25%, normal pressure leads to oxygen, and pretreated temperature is controlled at 60 ℃～80 ℃, time 1.5h～2.5h.
3. the technology of acetate according to claim 1/persulfate catalytic bleaching pulp is characterized in that: during to the association with pulp bleaching catalytic pretreatment, also added (NH
4)
2S
2O
8, (NH
4)
2S
2O
8Consumption and Cu (CH
3COO)
2Or Co (CH
3COO)
2Mol ratio be 2: 1.
4. according to the technology of claim 2 or 3 described acetate/persulfate catalytic bleaching pulps, it is characterized in that the process conditions of follow-up total chlorine free bleaching are:
1. the alkali treatment section strengthened of hydrogen peroxide, NaOH accounts for the consumption 1.0wt%～2.0wt% of paper pulp, hydrogen peroxide consumption 0.4wt%～0.6wt%, magnesium sulfate consumption 0.08wt%～0.12wt%, diethylene triamine pentacetic acid (DTPA) consumption 0.03wt%～0.07wt%, pulp density 8wt%～12wt% during processing, 65 ℃～75 ℃ of temperature, 0.5 hour～1.5 hours time;
2. hydrogen peroxide bleaching section, NaOH accounts for the consumption 1.0wt%～2.0wt% of paper pulp, magnesium sulfate consumption 0.08wt%～0.12wt%, sodium metasilicate consumption 0.8wt%～1.2wt%, diethylene triamine pentacetic acid (DTPA) consumption 0.08wt%～0.12wt%, hydrogen peroxide consumption 1.8wt%～2.2wt%, pulp density 8wt%～12wt% during processing, 75 ℃～85 ℃ of temperature, 2.0 hours～3.0 hours time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010541769.6A CN102061638B (en) | 2010-11-12 | 2010-11-12 | Process for catalytically bleaching pulp by acetate/persulfate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010541769.6A CN102061638B (en) | 2010-11-12 | 2010-11-12 | Process for catalytically bleaching pulp by acetate/persulfate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102061638A true CN102061638A (en) | 2011-05-18 |
| CN102061638B CN102061638B (en) | 2013-07-10 |
Family
ID=43997121
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010541769.6A Expired - Fee Related CN102061638B (en) | 2010-11-12 | 2010-11-12 | Process for catalytically bleaching pulp by acetate/persulfate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102061638B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102587186A (en) * | 2012-03-20 | 2012-07-18 | 昆明理工大学 | Method for bleaching dendrocalamus giganteus chemical pulp |
| CN109098026A (en) * | 2018-08-14 | 2018-12-28 | 中国林业科学研究院林产化学工业研究所 | A kind of method of reinforcing fiber raw material bleaching medicinal liquid osmosis |
| CN111979817A (en) * | 2020-07-20 | 2020-11-24 | 云南云景林纸股份有限公司 | Method for removing lignin from plant fiber |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06101186A (en) * | 1992-09-14 | 1994-04-12 | Mitsubishi Gas Chem Co Inc | Method for bleaching chemical pulp |
| JPH0770918A (en) * | 1993-08-23 | 1995-03-14 | Lion Corp | Bleaching method |
| CN1786335A (en) * | 2005-12-09 | 2006-06-14 | 华南理工大学 | Process for bleaching wheat straw grass pulp by alkaline method |
| CN101109160A (en) * | 2007-08-10 | 2008-01-23 | 昆明理工大学 | Novel non-chlorine bleaching technique for bamboo pulp |
| US20080110584A1 (en) * | 2006-11-15 | 2008-05-15 | Caifang Yin | Bleaching process with at least one extraction stage |
| CN101460675A (en) * | 2006-03-31 | 2009-06-17 | 奥伊兰南塔特基莫斯-维斯特恩研究股份有限公司 | Bleaching process of chemical pulp |
-
2010
- 2010-11-12 CN CN201010541769.6A patent/CN102061638B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06101186A (en) * | 1992-09-14 | 1994-04-12 | Mitsubishi Gas Chem Co Inc | Method for bleaching chemical pulp |
| JPH0770918A (en) * | 1993-08-23 | 1995-03-14 | Lion Corp | Bleaching method |
| CN1786335A (en) * | 2005-12-09 | 2006-06-14 | 华南理工大学 | Process for bleaching wheat straw grass pulp by alkaline method |
| CN101460675A (en) * | 2006-03-31 | 2009-06-17 | 奥伊兰南塔特基莫斯-维斯特恩研究股份有限公司 | Bleaching process of chemical pulp |
| US20080110584A1 (en) * | 2006-11-15 | 2008-05-15 | Caifang Yin | Bleaching process with at least one extraction stage |
| CN101109160A (en) * | 2007-08-10 | 2008-01-23 | 昆明理工大学 | Novel non-chlorine bleaching technique for bamboo pulp |
Non-Patent Citations (1)
| Title |
|---|
| 周学飞 等: "催化过氧化氢脱木素与漂白", 《纤维素科学与技术》, vol. 15, no. 2, 30 June 2007 (2007-06-30), pages 57 - 63 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102587186A (en) * | 2012-03-20 | 2012-07-18 | 昆明理工大学 | Method for bleaching dendrocalamus giganteus chemical pulp |
| CN102587186B (en) * | 2012-03-20 | 2015-03-11 | 昆明理工大学 | Method for bleaching dendrocalamus giganteus chemical pulp |
| CN109098026A (en) * | 2018-08-14 | 2018-12-28 | 中国林业科学研究院林产化学工业研究所 | A kind of method of reinforcing fiber raw material bleaching medicinal liquid osmosis |
| CN109098026B (en) * | 2018-08-14 | 2021-01-26 | 中国林业科学研究院林产化学工业研究所 | Method for enhancing penetration of fiber raw material bleaching liquor |
| CN111979817A (en) * | 2020-07-20 | 2020-11-24 | 云南云景林纸股份有限公司 | Method for removing lignin from plant fiber |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102061638B (en) | 2013-07-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101109160B (en) | Novel non-chlorine bleaching technique for bamboo pulp | |
| US10954630B2 (en) | Process for producing cellulose with low impurities from sugarcane bagasse | |
| CN1818157A (en) | Natural plant fibre extraction by alkali oxidation | |
| CN102061638B (en) | Process for catalytically bleaching pulp by acetate/persulfate | |
| CN103726377A (en) | Clean pulping method for low-polymerization degree bamboo pulp | |
| CN103382671A (en) | Clean pulping technology for high-polymerization-degree bamboo pulp | |
| CN101575820B (en) | Method for removing metal ions of paper pulp and bleaching | |
| CN104389222A (en) | ECF bleaching method for reducing AOX formation amount | |
| CN102587186B (en) | Method for bleaching dendrocalamus giganteus chemical pulp | |
| CN101306860B (en) | Chlorine dioxide bleaching process for reducing content of organic chloride in waste water | |
| CN102182094A (en) | Salix mongolica sulfate pulp bleaching process | |
| CN104195859B (en) | A kind of method of enzyme auxiliary silica chlorine bleaching bagasse pulp | |
| CN101760978A (en) | Pulp-bleaching technique | |
| CN110670398A (en) | Method for pulping broad-leaved wood by totally chlorine-free bleaching | |
| CN101565909B (en) | Little-chlorine and little-pollution bleaching process for paper pulp biomimetic pretreatment | |
| CN102191708B (en) | Method for carrying out elemental chlorine free (ECF) multistage bleaching on masson pine kraft pulp by using glyoxal | |
| CN101560740B (en) | Bleaching method for bleaching deinked waste pulp | |
| CN105040501A (en) | Total-chlorine-free bleaching method of reed pulp | |
| CA2044100A1 (en) | Biobleaching process | |
| CN103061185B (en) | Paper pulp fully chlorine-free bleaching method | |
| CN101265667A (en) | Cleaning production auxiliaries for pretreatment | |
| CN114908598B (en) | Oxygen bleaching method for paper pulp | |
| CN114541161A (en) | Bleaching method of non-wood pulp and bleached paper pulp | |
| CN102154871B (en) | Method for pulping without producing strongly alkaline high-pollution black liquor | |
| CN102852019B (en) | Totally chlorine-free bleaching method of bamboo pulp for producing Daqian writing and painting paper |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130710 Termination date: 20141112 |
|
| EXPY | Termination of patent right or utility model |