CN112758957A - Process for purifying sodium hydroxide concentration by electrodialysis - Google Patents
Process for purifying sodium hydroxide concentration by electrodialysis Download PDFInfo
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- CN112758957A CN112758957A CN202011583856.8A CN202011583856A CN112758957A CN 112758957 A CN112758957 A CN 112758957A CN 202011583856 A CN202011583856 A CN 202011583856A CN 112758957 A CN112758957 A CN 112758957A
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- concentration
- sodium hydroxide
- alkali liquor
- sodium sulfate
- electrodialysis
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
- C01D1/04—Hydroxides
- C01D1/28—Purification; Separation
- C01D1/38—Purification; Separation by dialysis
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F13/00—Recovery of starting material, waste material or solvents during the manufacture of artificial filaments or the like
- D01F13/02—Recovery of starting material, waste material or solvents during the manufacture of artificial filaments or the like of cellulose, cellulose derivatives or proteins
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
- Y02P70/62—Manufacturing or production processes characterised by the final manufactured product related technologies for production or treatment of textile or flexible materials or products thereof, including footwear
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Urology & Nephrology (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Textile Engineering (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a process for purifying sodium hydroxide concentration by electrodialysis, which comprises the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, and adjusting the pH value after crystallization; 3) adding desalted water to remove impurities and filtering; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) and (3) filtering the sodium hydroxide solution by a nanofiltration membrane, and separating the sodium hydroxide solution into high-concentration alkali liquor and low-concentration alkali liquor by an electrodialysis assembly, wherein the high-concentration alkali liquor is directly used for the primary alkali liquor and the secondary alkali liquor, and the low-concentration alkali liquor is returned to the step 3) for recycling. Product Na produced by viscose fiber production according to the invention2SO4The acid liquor and the alkali liquor generated by the recovery treatment are recycled and changed into Na2SO4Waste is valuable, and simultaneously, the use of caustic soda is greatly reduced, thereby achievingThe purpose of recycling the alkali liquor is achieved.
Description
Technical Field
The invention relates to the technical field of viscose fiber production, in particular to a process for purifying sodium hydroxide concentration by electrodialysis.
Background
In the production process of viscose fibers, a plurality of procedures such as primary impregnation, secondary impregnation, tertiary impregnation, yellowing dissolution and the like of pulp all need to use caustic soda to prepare alkali liquor with proper concentration, so the caustic soda usage amount in the whole process flow is huge, and the cost is high; while the product Na is produced in the subsequent process2SO4Also adopts a low-price selling mode to process, and the Na is generated2SO4Is discarded in large quantities.
Disclosure of Invention
The technical problems to be solved by the invention are that the existing viscose fiber production process needs to use a large amount of caustic soda, the cost is high, and meanwhile, the product Na2SO4A large amount of wastes, and aims to provide a process for purifying the concentration of sodium hydroxide by electrodialysis, namely a product Na generated by viscose fiber production2SO4The acid liquor and the alkali liquor generated by the recovery treatment are recycled and changed into Na2SO4The waste is used as valuable, and simultaneously, the use of caustic soda is greatly reduced, thereby achieving the purpose of recycling the alkali liquor.
The invention is realized by the following technical scheme:
a process for purifying sodium hydroxide concentration by electrodialysis, comprising the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, and adjusting the pH value after crystallization; 3) adding desalted water to remove impurities and filtering; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device, and then introducing desalted water into an acid flow channel and an alkali flow channel of the bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, the sodium hydroxide solution is filtered by a nanofiltration membrane and then is separated into high-concentration alkali liquor and low-concentration alkali liquor through an electrodialysis assembly, the high-concentration alkali liquor is directly used for the first-leaching alkali liquor and the second-leaching alkali liquor, and the low-concentration alkali liquor is returned to the step 3) for reuse.
And (5) returning the residual sodium sulfate at the position where the sodium hydroxide solution is filtered by the nanofiltration membrane in the step 3) to the step for recycling treatment.
Sodium sulfate in the step 1) is directly dissolved by adopting desalted water.
The specific process of step 2) is as follows: the viscose waste liquid is crystallized after being concentrated and then is separated by a centrifuge, so as to obtain powdery solid containing sodium sulfate, zinc sulfate and sulfuric acid and concentrated sulfuric acid solution, the concentrated sulfuric acid solution is directly conveyed to an acid bath process in the viscose production process through a pipeline, and the powdery solid containing the sodium sulfate, the zinc sulfate and the dilute sulfuric acid is placed in a transfer tank for the next process.
And 3) adding desalted water into the transfer tank to dissolve the powdery solid to obtain a solution containing 5-30% of sodium sulfate, zinc sulfate and sulfuric acid.
And 3) sequentially carrying out primary filtration, secondary primary filtration, ion exchange filtration and pp microporous filtration fine filtration on the dissolved solution.
The filtering process in the step 3) comprises settling in a preparation tank, filtering in a primary bag filter, secondary settling in the preparation tank, secondary filtering in the bag filter, primary adsorption in a resin tower and secondary adsorption in the resin tower in sequence.
The concrete operation of the settling of the blending tank is as follows: and (3) adding alkali into the dissolved solution to neutralize to form a weakly alkaline environment, forming solid flocculent precipitate by impurity metal ions, carrying out precipitation, sedimentation and separation, discharging and recycling the physically precipitated precipitate by utilizing a sewage discharge outlet of a U-shaped sewage discharge device, and pumping out supernate to enter a post-filtering process.
The treatment method of the invention is to grow the viscose fiberThe product Na is produced2SO4Recovering to obtain acid solution and alkali solution, concentrating the sulfuric acid solution for use in acid station, and removing residual Na from 4-9% sodium hydroxide by nanofiltration membrane2SO4 can be directly used for blending of xanthation dissolving alkali, primary soaking alkali solution and secondary soaking alkali solution in the viscose fiber production process, but in this case, a certain amount of caustic soda still needs to be added to meet the concentration requirements of primary soaking of 23% of sodium hydroxide (bipolar membrane filtrate: caustic soda is 3: 1) and secondary soaking of 12% of sodium hydroxide (bipolar membrane filtrate: caustic soda is 10: 1), and a large amount of caustic soda still needs to be used.
Therefore, the sodium hydroxide nanofiltration membrane filtrate is further separated into high-concentration alkali liquor and low-concentration alkali liquor through the electrodialysis assembly on the basis of 4% -9% of the sodium hydroxide nanofiltration membrane filtrate, the high-concentration alkali liquor can meet the concentration requirements of primary and secondary caustic soaks and can be directly used without using additional caustic soda for blending, the use of caustic soda is greatly reduced, and the sodium hydroxide is changed into Na2SO4The waste is used as a treasure, the purpose of recycling alkali liquor is achieved, low-concentration alkali liquor is recycled for brine pretreatment, and the alkali and water are fully utilized.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the invention relates to a process for purifying sodium hydroxide concentration by electrodialysis, which changes Na into Na while greatly reducing the use of caustic soda2SO4 is used as a fertilizer, and Na is reduced2SO4The waste amount of the alkali liquor reaches the purpose of recycling the alkali liquor.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a flow chart of a conventional viscose fiber production process;
FIG. 2 is a flow chart of the recycling of lye of the present invention;
FIG. 3 is a flow chart of the recycling of lye of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
The invention relates to a process for purifying sodium hydroxide concentration by electrodialysis, which comprises the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, carrying out pH adjustment after crystallization, separating by a centrifuge to obtain powdery solid containing sodium sulfate, zinc sulfate and sulfuric acid and concentrated sulfuric acid solution, directly conveying the concentrated sulfuric acid solution to an acid bath process in the viscose production process through a pipeline, and placing the powdery solid containing the sodium sulfate, the zinc sulfate and dilute sulfuric acid in a transfer tank; 3) adding desalted water into the transfer tank to dissolve the powdery solid to obtain a solution containing 5% -30% of sodium sulfate, zinc sulfate and sulfuric acid, and sequentially performing primary filtration, secondary primary filtration, ion exchange filtration and pp microporous filtration fine filtration on the solution through settling of a preparation tank, filtration of a primary bag filter, secondary settling of the preparation tank, secondary filtration of the bag filter, primary adsorption of a resin tower and secondary adsorption of the resin tower; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device, and then introducing desalted water into an acid flow channel and an alkali flow channel of the bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, the sodium hydroxide solution is filtered by a nanofiltration membrane and then is separated into high-concentration alkali liquor and low-concentration alkali liquor through an electrodialysis assembly, the high-concentration alkali liquor is directly used for the first-leaching alkali liquor and the second-leaching alkali liquor, and the low-concentration alkali liquor is returned to the step 3) for reuse.
As shown in fig. 1, which is a flow chart of the existing viscose fiber production process, it can be seen that a large amount of caustic soda needs to be added to prepare alkali liquor in the production process, the usage amount of the caustic soda is large, and a large amount of sodium sulfate generated at the end of the process is wasted; FIG. 2 is a process of recycling sodium sulfate generated at the end of the process by using the method of the present invention, and it can be seen from the flow chart of FIG. 2 that acid solution and 4-9% sodium hydroxide solution can be generated by subjecting sodium sulfate to a certain treatment, and the 4-9% sodium hydroxide solution can be returned to the viscose fiber production process for blending the xanthation dissolved alkali solution, the primary leaching alkali solution and the secondary leaching alkali solution; fig. 3 is a diagram of further performing electrodialysis treatment on the basis of 4-9% sodium hydroxide solution, so that 23% high-concentration sodium hydroxide solution and 12% sodium hydroxide solution can be obtained, the requirements of primary caustic soda concentration and secondary caustic soda concentration in the viscose fiber production process are met, the viscose fiber can be directly used without using caustic soda for blending, the use of caustic soda is reduced, waste sodium sulfate is changed into valuable, the recycling of alkali liquor is realized, the use amount of caustic soda in the whole process flow is greatly saved, and the production cost is reduced.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. The process for purifying the concentration of sodium hydroxide by electrodialysis is characterized by comprising the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, and adjusting the pH value after crystallization; 3) adding desalted water to remove impurities and filtering; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device, and then introducing desalted water into an acid flow channel and an alkali flow channel of the bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, the sodium hydroxide solution is filtered by a nanofiltration membrane and then is separated into high-concentration alkali liquor and low-concentration alkali liquor through an electrodialysis assembly, the high-concentration alkali liquor is directly used for the first-leaching alkali liquor and the second-leaching alkali liquor, and the low-concentration alkali liquor is returned to the step 3) for reuse.
2. The process for purifying the concentration of the sodium hydroxide by electrodialysis as claimed in claim 1, wherein the residual sodium sulfate in the sodium hydroxide solution filtered by the nanofiltration membrane in step 5) is returned to the recovery treatment in step 3).
3. The process for electrodialytic purification of sodium hydroxide concentration according to claim 1, wherein sodium sulfate in step 1) is directly dissolved by desalted water.
4. The process for electrodialytically purifying sodium hydroxide concentration according to claim 1, wherein the specific process of the step 2) is as follows: the viscose waste liquid is crystallized after being concentrated and then is separated by a centrifuge, so as to obtain powdery solid containing sodium sulfate, zinc sulfate and sulfuric acid and concentrated sulfuric acid solution, the concentrated sulfuric acid solution is directly conveyed to an acid bath process in the viscose production process through a pipeline, and the powdery solid containing the sodium sulfate, the zinc sulfate and the dilute sulfuric acid is placed in a transfer tank for the next process.
5. The process for purifying the concentration of sodium hydroxide by electrodialysis as claimed in claim 4, wherein the step 3) is carried out by adding desalted water into the transfer tank to dissolve the powdery solid to obtain a solution containing 5% -30% sodium sulfate, zinc sulfate and sulfuric acid.
6. The process of electrodialysis purification of sodium hydroxide concentration as claimed in claim 5, wherein in step 3), the dissolved solution is sequentially subjected to primary filtration, secondary primary filtration, ion exchange filtration and pp microfiltration fine filtration.
7. The process for purifying the concentration of sodium hydroxide by electrodialysis as claimed in claim 6, wherein the filtration process in step 3) comprises settling in a preparation tank, filtration by a primary bag filter, secondary settling in a preparation tank, secondary filtration by a bag filter, primary adsorption by a resin tower and secondary adsorption by a resin tower in sequence.
8. The process for electrodialytic purification of sodium hydroxide concentration according to claim 7, wherein the specific operation of settling in the preparation tank is as follows: and (3) adding alkali into the dissolved solution to neutralize to form a weakly alkaline environment, forming solid flocculent precipitate by impurity metal ions, carrying out precipitation, sedimentation and separation, discharging and recycling the physically precipitated precipitate by utilizing a sewage discharge outlet of a U-shaped sewage discharge device, and pumping out supernate to enter a post-filtering process.
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| CN202011583856.8A CN112758957A (en) | 2020-12-28 | 2020-12-28 | Process for purifying sodium hydroxide concentration by electrodialysis |
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| CN202011583856.8A CN112758957A (en) | 2020-12-28 | 2020-12-28 | Process for purifying sodium hydroxide concentration by electrodialysis |
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Cited By (2)
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| CN112725942A (en) * | 2020-12-28 | 2021-04-30 | 宜宾丝丽雅股份有限公司 | Viscose sodium sulfate waste liquid regeneration and recycling process |
| CN115677797A (en) * | 2022-10-27 | 2023-02-03 | 四川雅华生物有限公司 | Four-membrane combined process suitable for preparing xylose from hemicellulose |
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| CN115677797A (en) * | 2022-10-27 | 2023-02-03 | 四川雅华生物有限公司 | Four-membrane combined process suitable for preparing xylose from hemicellulose |
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Application publication date: 20210507 |