CN101532263A - Method for irradiating NaClO-bleached wheat straw pulp on a microwave - Google Patents
Method for irradiating NaClO-bleached wheat straw pulp on a microwave Download PDFInfo
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- CN101532263A CN101532263A CN200910068432A CN200910068432A CN101532263A CN 101532263 A CN101532263 A CN 101532263A CN 200910068432 A CN200910068432 A CN 200910068432A CN 200910068432 A CN200910068432 A CN 200910068432A CN 101532263 A CN101532263 A CN 101532263A
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Abstract
The invention discloses a method for irradiating NaClO-bleached wheat straw pulp on a microwave basis and aims to provide a method for irradiating NaClO-bleached wheat straw pulp on a microwave basis, which can ensure that the viscosity and the K value of the pulp are optimized, prevent cellulose and hemi-cellulose thereof from being destroyed and optimize the quality of the pulp on the basis that the bleaching effect of the pulp is guaranteed. The method comprises the following steps: dispersing the unbleached wheat straw pulp; preparing the unbleached wheat straw pulp into a suspension with the concentration of the pulp being 10% (mass percentage); further adjusting the pH value of the suspension to 8.0 to 11.0 with alkali; then, adding NaClO with the mass percentage being 4.2% of the absolute-dry wheat straw pulp, and evenly stirring; and irradiating for 2.5 minutes on a microwave with the service power of 240W to obtain the bleached pulp. By optimizing the major factors influencing the whiteness, the viscosity and the K value of the pulp, the invention can ensure that the viscosity and the K value of the pulp are optimized, prevent cellulose and hemi-cellulose thereof from being destroyed and optimize the quality of the pulp on the basis that the bleaching effect of the pulp is guaranteed.
Description
Technical field
The present invention relates to field of papermaking, in particular, relate to a kind of paper pulp bleaching process.
Background technology
Pulp and paper industry is the mainstay of Chinese national economy, and association with pulp bleaching occupies an important position in the paper process.The main purpose of bleaching is the stability that improves the whiteness of paper pulp and increase pulp brightness, improves the physicochemical properties of paper pulp, purifying paper pulp cleanliness factor.In using the bleaching process of NaClO as bleaching agent, traditional heater means is the water-bath heating.Along with the development of microwave technology, use microwave to replace the water-bath heating to become the direction of research gradually.At number of patent application is 2004100190995., denomination of invention is for disclosing a kind of method of microwave radiation NaClO bleached wheat straw pulp in the patent application of " method of microwave radiation hypochlorite association with pulp bleaching ", do not relate to employed microwave power in this method under the situation that guarantees bleaching, to the viscosity of paper pulp, the adverse effect that hardness produces, and, bleaching time is long bigger to destructions such as cellulose, hemicelluloses, influences pulp quality.
Summary of the invention
The present invention is in order to overcome weak point of the prior art, provide a kind of on the basis that guarantees the association with pulp bleaching treatment effect, make viscosity, the K value of paper pulp reach optimum value, and, can not destroy cellulose, hemicellulose, make paper pulp that the method for the microwave radiation NaClO bleached wheat straw pulp of best in quality be arranged.
The present invention is achieved through the following technical solutions:
A kind of method of microwave radiation NaClO bleached wheat straw pulp, it is characterized in that, after comprising the steps: not float the Straw Pulp dispersion, make the suspension that pulp density is 10% (mass percent), add alkali again and regulate the pH value, afterwards, add mass percent with respect to the over dry Straw Pulp and be 4.2% NaClO and stir to 8.0-11.0, use power to be the microwave radiation of 240W 2.5 minutes, the paper pulp that obtains bleaching.
The NaClO consumption is very big to the influence of association with pulp bleaching, and consumption does not reach bleaching effect very little, and consumption too much can do great damage to fibre length again, finds by analysis of experiments, increases with the NaClO consumption, and pulp brightness improves, and pulp viscosity and K value descend., increase with the NaClO consumption in 0～4.2% scope at the NaClO consumption, pulp brightness improves very fast, brings up to 60.46%ISO by 29.32%ISO, has increased by 41 left and right sides percentage points; Pulp viscosity is by 772.99mLg
-1Drop to 651.35mLg
-1The K value drops to 4.53 by 7.76.But continue to increase the NaClO consumption, pulp brightness improves but very limited, is increased to 6.2% at the NaClO consumption by 4.2%, and pulp brightness has only improved less than 1.21%ISO; The K value is constant substantially; And pulp viscosity sharply descends, by 651.35mLg
-1Drop to 510.89mLg
-1On the whole, the residual chlorine in the microwave radiation bleaching effluent all seldom, in 6.2% scope, residual chlorine is all at 0.2Lg at the NaClO consumption
-1In the scope, can not cause big pollution to environment.Take all factors into consideration pulp brightness, K value and viscosity, the NaClO consumption should be controlled in 4.2%.
Microwave irradiation power has reacted the certain reaction temperature to a certain extent.For association with pulp bleaching, ClO
-The speed influence that discharges is bigger, and reasonably radiant power has determined ClO
-Suitable rate of release has also determined the reaction effect of itself and paper pulp.Find that by analysis of experiments improve with microwave irradiation power, pulp brightness raises, radiant power is when 160～220W, and pulp brightness raises very fast, rises to 60.38%ISO by 59.23%ISO; Radiant power rises to after the 220W, and pulp brightness improves trend and slows down to some extent.This may be because within a certain period of time, when microwave power is brought up to 220W, the NaClO overwhelming majority decomposes and is used for bleached pulp, when radiant power improves again, though NaClO decomposes and the raising of association with pulp bleaching speed in theory, but this moment, NaClO was exhausted substantially, so pulp brightness almost no longer raises.Improve with microwave irradiation power, paper pulp K value and viscosity descend always.Within a certain period of time, when microwave power was brought up to 220W, though NaClO is exhausted substantially, the lag phase appearred in pulp brightness, and lignin, cellulose, hemicellulose and carbohydrate are further destroyed, so viscosity and K value continue to reduce.Take all factors into consideration, microwave irradiation power is controlled at about 240W.For association with pulp bleaching, bleaching time is too short can not to reach bleaching effect, and bleaching time is long might to cause too much destruction to fiber again.Find that by analysis of experiments increase with microwave irradiation time, the Changing Pattern of pulp brightness probably can be divided into for two stages.Preceding 2.5min increases with radiated time, and pulp brightness improves very fast, brings up to 61.56%ISO by 29.32%ISO, has increased 32.24%ISO, and when radiated time arrived 2.5min, it is the highest that pulp brightness reaches, and is 61.56%ISO; 2.5min be later on second stage, descending appears in pulp brightness prolongation in time.Reason is that the NaClO in the bleaching liquor runs out of substantially to the bleaching later stage, and paper pulp can not further be bleached, and paper pulp is in being in the high-temperature alkaline environment for a long time, thereby causes yellowing reversion of pulp, so pulp brightness decline to some extent on the contrary.Increase with microwave irradiation time, paper pulp K value and viscosity all descend.Take all factors into consideration above factor, microwave irradiation time should be controlled at about 2.5min.
Regulate the pH value at 8.0-11.0, this is because NaClO solution is extremely unstable, adds acid and just can decomposite chlorine rapidly, and carbon dioxide in air also can make it decompose, and therefore, in NaClO solution, excessive alkali must be arranged, and could keep the stable of solution., loses solution bleaching power otherwise will progressively decomposing.
1. compare with the patented method in the background technology, the present invention passes through the optimization to the principal element that influences pulp brightness, viscosity and K value, can be when guaranteeing the association with pulp bleaching effect, make viscosity, the K value of paper pulp reach optimum value, and, can not destroy the fibre length of paper pulp, make paper pulp that best in quality be arranged, thereby for adopting microwave radiation bleached pulp suitability for industrialized production that reliable guarantee is provided.
2. microwave radiation bleached pulp, reaching when adding the corresponding whiteness of thermal bleaching with water-bath, microwave radiation bleached pulp viscosity does not too much descend, and promptly microwave radiation can not cause too much destruction to the fibre length of paper pulp, for the industrialization of microwave radiation association with pulp bleaching is laid a good foundation.
3. microwave radiation bleaching adds thermal bleaching with water-bath and compares, and when reaching certain whiteness, the residual chlorine in the microwave radiation bleaching effluent heats much less than water-bath, helps wastewater treatment and environmental protection
4. the present invention bleaches by microwave radiation, and the bleaching required time shortens greatly, helps the raising of energy saving and operating efficiency.
The specific embodiment
Below in conjunction with specific embodiment to the detailed description of the invention.
Embodiment 1:
After taking by weighing the over dry Straw Pulp 10g dispersion of not bleaching processing, make the suspension that pulp density is 10% (mass percent), add NaOH again and regulate the pH value to 8.0-11.0, afterwards, adding is that 4.2% NaClO stirs with respect to the mass percent of over dry Straw Pulp, use power to be the microwave radiation of 240W 2.5 minutes, the paper pulp that obtains bleaching, pulp brightness reaches more than the 61%ISO.
Claims (1)
1, a kind of method of microwave radiation NaClO bleached wheat straw pulp, it is characterized in that, after comprising the steps: not float the Straw Pulp dispersion, make the suspension that pulp density is 10% (mass percent), add alkali again and regulate the pH value, afterwards, add mass percent with respect to the over dry Straw Pulp and be 4.2% NaClO and stir to 8.0-11.0, use power to be the microwave radiation of 240W 2.5 minutes, the paper pulp that obtains bleaching.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910068432A CN101532263A (en) | 2009-04-10 | 2009-04-10 | Method for irradiating NaClO-bleached wheat straw pulp on a microwave |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910068432A CN101532263A (en) | 2009-04-10 | 2009-04-10 | Method for irradiating NaClO-bleached wheat straw pulp on a microwave |
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| CN101532263A true CN101532263A (en) | 2009-09-16 |
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| CN200910068432A Pending CN101532263A (en) | 2009-04-10 | 2009-04-10 | Method for irradiating NaClO-bleached wheat straw pulp on a microwave |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103110190A (en) * | 2013-02-04 | 2013-05-22 | 湖北中烟工业有限责任公司 | Cigarette filter made of loofah sponge fiber and preparation method thereof |
| CN111676723A (en) * | 2020-06-17 | 2020-09-18 | 陕西科技大学 | Microwave-hot alkali pretreatment assisted wood delignification method |
-
2009
- 2009-04-10 CN CN200910068432A patent/CN101532263A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103110190A (en) * | 2013-02-04 | 2013-05-22 | 湖北中烟工业有限责任公司 | Cigarette filter made of loofah sponge fiber and preparation method thereof |
| CN103110190B (en) * | 2013-02-04 | 2014-12-10 | 湖北中烟工业有限责任公司 | Cigarette filter made of loofah sponge fiber and preparation method thereof |
| CN111676723A (en) * | 2020-06-17 | 2020-09-18 | 陕西科技大学 | Microwave-hot alkali pretreatment assisted wood delignification method |
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Open date: 20090916 |