CN114949909A - Continuous crystallization process of oxalic acid - Google Patents
Continuous crystallization process of oxalic acid Download PDFInfo
- Publication number
- CN114949909A CN114949909A CN202210560678.XA CN202210560678A CN114949909A CN 114949909 A CN114949909 A CN 114949909A CN 202210560678 A CN202210560678 A CN 202210560678A CN 114949909 A CN114949909 A CN 114949909A
- Authority
- CN
- China
- Prior art keywords
- oxalic acid
- stock solution
- crystallization
- crystallizer
- cooling
- 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.)
- Pending
Links
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 title claims abstract description 162
- 238000002425 crystallisation Methods 0.000 title claims abstract description 58
- 230000008025 crystallization Effects 0.000 title claims abstract description 58
- 235000006408 oxalic acid Nutrition 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000011550 stock solution Substances 0.000 claims abstract description 56
- 238000001816 cooling Methods 0.000 claims abstract description 52
- 239000013078 crystal Substances 0.000 claims abstract description 33
- 238000001704 evaporation Methods 0.000 claims abstract description 32
- 239000007788 liquid Substances 0.000 claims abstract description 32
- 230000008020 evaporation Effects 0.000 claims abstract description 31
- 239000002002 slurry Substances 0.000 claims abstract description 28
- 239000000463 material Substances 0.000 claims abstract description 15
- 239000002904 solvent Substances 0.000 claims abstract description 7
- 238000007599 discharging Methods 0.000 claims abstract description 6
- 238000010992 reflux Methods 0.000 claims abstract description 6
- 238000003756 stirring Methods 0.000 claims description 9
- 239000002245 particle Substances 0.000 abstract description 9
- 239000000203 mixture Substances 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 5
- 238000005265 energy consumption Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0018—Evaporation of components of the mixture to be separated
- B01D9/0022—Evaporation of components of the mixture to be separated by reducing pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0063—Control or regulation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/02—Crystallisation from solutions
-
- 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
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of oxalic acid crystallization, in particular to a continuous crystallization process of oxalic acid. Which comprises the following steps: adding the oxalic acid stock solution into a concentration tank, then starting a stock solution pump to inject the oxalic acid stock solution into an evaporation crystallizer, and evaporating a solvent in the evaporation crystallizer to perform primary crystallization on the stock solution; then the mixture enters a cooling crystallizer for cooling and secondary crystallization; feeding the feed liquid containing a certain crystal slurry ratio into a mother material barrel, discharging the feed liquid into a cooling crystallizer through a reflux pump, and carrying out heat exchange, cooling and crystallization again; in the continuous oxalic acid crystallization process, an oxalic acid stock solution is continuously fed into an evaporation crystallizer, the concentration of the evaporation concentrated stock solution is 52-58%, primary crystals are obtained, then the primary crystals are fed into a cooling crystallizer for cooling, and the primary crystals are cooled and crystallized through continuous heat exchange to obtain large-particle oxalic acid crystals.
Description
Technical Field
The invention relates to the technical field of oxalic acid crystallization, in particular to a continuous crystallization process of oxalic acid.
Background
Crystallization refers to a separation process of separating out solid crystals from solution, steam or melt, and a crystallization process is an important operation unit in a chemical process and also an important link for finishing the generation of chemical products. Crystallization is achieved by lowering the temperature or removing part of the solvent. In the formation, this is achieved mainly by crystallizers, which yield a crystalline product suitable for the requirements.
In the existing oxalic acid crystallization process, firstly, oxalic acid solution is injected into a crystallizer for single-pass crystallization operation, so that the crystal particles are small, the purity is low, and the total content is low; secondly, an intermittent crystallization production process is adopted, so that the crystallization time is longer and the energy consumption is larger, and therefore, a continuous recrystallization process for re-melting and purifying oxalic acid is urgently needed to overcome the defects of the prior art.
Disclosure of Invention
The invention aims to provide a continuous oxalic acid crystallization process to solve the problems in the background technology.
In order to achieve the aim, the invention provides a continuous oxalic acid crystallization process, which comprises the following steps:
s1, adding the oxalic acid stock solution into a concentration tank, adjusting the concentration, and preheating for later use;
s2, starting a vacuum pump to pump out air in the evaporative crystallizer, and then starting a stock solution pump to inject the oxalic acid stock solution into the evaporative crystallizer so as to evaporate the solvent in the evaporative crystallizer to perform primary crystallization;
s3, cooling the stock solution after the evaporation step in a cooling crystallizer to ensure that the stock solution is cooled in the cooling crystallizer for secondary crystallization;
s4, feeding the feed liquid containing a certain crystal slurry ratio into a mother material barrel, discharging the feed liquid into a cooling crystallizer through a reflux pump, carrying out heat exchange cooling crystallization again, and obtaining large-particle oxalic acid crystal slurry through a continuous heat exchange cooling mode;
and S5, finally, conveying the feed liquid to a slurry barrel, starting a slurry barrel stirrer for stirring, and opening a slurry barrel discharge valve to enable the material to enter a centrifugal machine to separate oxalic acid crystals.
As a further improvement of the technical scheme, in the S1, the concentration of the oxalic acid stock solution is 18-23%, and the preheating temperature is 70-90 ℃.
As a further improvement of the technical scheme, in S2, the evaporation temperature of the evaporation crystallizer is 70-90 ℃, the concentration degree of the stock solution after evaporation is 52-58%, and the temperature is reduced to 45-50 ℃ after evaporation.
As a further improvement of the technical scheme, in the S2, when the liquid level height in the evaporative crystallizer reaches 4-4.5m, the raw liquid is stopped entering.
As a further improvement of the technical scheme, in S3, the cooling temperature of the cooling crystallizer is-5 ℃, and the upper-lower difference is 1 ℃.
As a further improvement of the technical solution, in S3, when the cooling crystallizer discharges, the raw liquid pump is turned on to continuously feed the raw liquid into the evaporative crystallizer, so as to reduce the crystallization time and improve the crystallization efficiency.
As a further improvement of the technical scheme, in the S4, the continuous heat exchange time is 3.5-4.5h to realize crystallization.
Compared with the prior art, the invention has the following beneficial effects:
in the continuous oxalic acid crystallization process, an oxalic acid stock solution is continuously fed into an evaporation crystallizer, the concentration of the evaporation concentrated stock solution is 52-58 percent, primary crystals are obtained, then the primary crystals are fed into a cooling crystallizer for cooling, and large-particle oxalic acid crystals are obtained through continuous heat exchange, cooling and crystallization.
Drawings
FIG. 1 is an overall flow diagram of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
1. Adding the oxalic acid stock solution into a concentration tank, adjusting the concentration to 18%, and preheating to 70 ℃ for later use;
2. starting a vacuum pump to pump out air in the evaporative crystallizer, then starting a stock solution pump to inject an oxalic acid stock solution into the evaporative crystallizer, stopping the stock solution pump after the liquid level height reaches 4-4.5m, stopping the stock solution from entering, adjusting the temperature to 70 ℃, and performing primary crystallization on the evaporation solvent of the stock solution in the evaporative crystallizer, wherein the concentration of the stock solution after crystallization is 52%, and the temperature is reduced to 45 ℃;
3. the stock solution after the evaporation step enters a cooling crystallizer to be cooled to minus 6 ℃, so that the stock solution is cooled in the cooling crystallizer for secondary crystallization, and when the cooling crystallizer discharges materials, a stock solution pump is opened to continuously enter the evaporation crystallizer, so that the crystallization time is shortened, and the crystallization efficiency is improved;
4. feeding a feed liquid containing a certain crystal slurry ratio into a mother material barrel, discharging the feed liquid into a cooling crystallizer through a reflux pump, carrying out heat exchange cooling crystallization again for 4.5 hours, and obtaining large-particle oxalic acid crystal slurry in a continuous heat exchange cooling mode;
5. and finally, conveying the feed liquid to a slurry barrel, starting a slurry barrel stirrer for stirring, and opening a slurry barrel discharge valve to enable the material to enter a centrifugal machine to separate out oxalic acid crystals.
Example 2
1. Adding the oxalic acid stock solution into a concentration tank, adjusting the concentration to 20%, and preheating to 80 ℃ for later use;
2. starting a vacuum pump to pump out air in the evaporative crystallizer, then starting a stock solution pump to inject an oxalic acid stock solution into the evaporative crystallizer, stopping the stock solution pump after the liquid level height reaches 4-4.5m, stopping the stock solution from entering, adjusting the temperature to 80 ℃, and performing primary crystallization on the evaporation solvent of the stock solution in the evaporative crystallizer, wherein the concentration of the stock solution after crystallization is 55%, and the temperature is reduced to 48%;
3. the stock solution after the evaporation step enters a cooling crystallizer to be cooled to-5 ℃, so that the stock solution is cooled in the cooling crystallizer for secondary crystallization, and when the cooling crystallizer discharges materials, a stock solution pump is started to continuously enter the evaporation crystallizer, so that the crystallization time is shortened, and the crystallization efficiency is improved;
4. feeding a feed liquid containing a certain crystal slurry ratio into a mother material barrel, discharging the feed liquid into a cooling crystallizer through a reflux pump, carrying out heat exchange cooling crystallization again for 4 hours, and obtaining large-particle oxalic acid crystal slurry in a continuous heat exchange cooling mode;
5. and finally, conveying the feed liquid to a slurry barrel, starting a slurry barrel stirrer for stirring, and opening a slurry barrel discharge valve to enable the material to enter a centrifugal machine to separate out oxalic acid crystals.
Example 3
1. Adding the oxalic acid stock solution into a concentration tank, adjusting the concentration to 23%, and preheating to 90 ℃ for later use;
2. starting a vacuum pump, pumping out air in the evaporative crystallizer, then starting a stock solution pump to inject an oxalic acid stock solution into the evaporative crystallizer, stopping the stock solution pump after the liquid level height reaches 4-4.5m, stopping the stock solution from entering, adjusting the temperature to 90 ℃, and performing primary crystallization on the evaporation solvent of the stock solution in the evaporative crystallizer, wherein the concentration of the stock solution after crystallization is 58%, and the temperature is reduced to 50%;
3. the stock solution after the evaporation step enters a cooling crystallizer to be cooled to-4 ℃, so that the stock solution is cooled in the cooling crystallizer for secondary crystallization, and when the cooling crystallizer discharges materials, a stock solution pump is opened to continuously enter the evaporation crystallizer, so that the crystallization time is shortened, and the crystallization efficiency is improved;
4. feeding a feed liquid containing a certain crystal slurry ratio into a mother material barrel, discharging the feed liquid into a cooling crystallizer through a reflux pump, carrying out heat exchange cooling crystallization again for 4.5 hours, and obtaining large-particle oxalic acid crystal slurry in a continuous heat exchange cooling mode;
5. and finally, conveying the feed liquid to a slurry barrel, starting a slurry barrel stirrer for stirring, and opening a slurry barrel discharge valve to enable the material to enter a centrifugal machine to separate out oxalic acid crystals.
The specific models and operating principles of the devices used in the above-described embodiments 1-3 are described as follows:
the diameter of the evaporation crystallizer is 1400cm, the height of the evaporation crystallizer is 5000cm, and the height of the upper conical end socket and the lower conical end socket is 1000 cm; the working principle is that after the preheated stock solution is injected into the crystallizer, the flash evaporation effect is immediately generated, the steam can be instantly pumped away, and then the cooling process is continuously started, so that the crystallization is realized;
the diameter of the cooling crystallizer is 1400cm, the height of the cooling crystallizer is 5000cm, and the height of the upper conical end socket and the lower conical end socket is 1000 cm; the working principle is that a material solution is cooled and crystallized in a cooling mode;
the diameter of the slurry barrel is 2000cm, the height of the slurry barrel is 2000cm, and the working principle of the slurry barrel is that a motor drives stirring blades in the barrel to stir slurry;
the diameter of the mother liquid barrel is 2000cm, the height of the mother liquid barrel is 2000cm, and the working principle of the mother liquid barrel is that a motor drives stirring blades in the barrel to stir the mother liquid.
In the process adopted in the embodiment 1-3 of the invention, the oxalic acid stock solution is continuously fed into an evaporation crystallizer, the concentration of the evaporation concentrated stock solution is 40 percent, primary crystals are obtained, then the primary crystals are fed into a cooling crystallizer for cooling, and the large-particle oxalic acid crystals are obtained by continuous heat exchange, cooling and crystallization, wherein the process is continuous operation, the product granularity is uniform, the purity is high, the crystal production time is short, and the energy consumption is low; in order to verify that the oxalic acid crystal produced by the process of the invention has higher purity and yield, the specific steps are shown in tables 1-2:
TABLE 1 Process parameters
Table 2 parameters of oxalic acid crystals
According to the processes adopted in the embodiments 1-3 of the invention, as shown in the table 1 and the table 2, the oxalic acid stock solution continuously enters the evaporation crystallizer to obtain primary crystals, then enters the cooling crystallizer to be cooled, and is cooled and crystallized through continuous heat exchange to obtain large-particle oxalic acid crystals, wherein the crystal size is 1.8-2.1mm, the content reaches 85.2-86.3% of the total, and the product purity is more than 96.6%, so that the oxalic acid crystals prepared by the process have high purity and large size.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and the preferred embodiments of the present invention are described in the above embodiments and the description, and the present invention is not limited to the embodiments, and various changes and modifications may be made without departing from the spirit and scope of the present invention, and these changes and modifications fall within the scope of the claimed invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A process for continuously crystallizing oxalic acid is characterized by comprising the following steps:
s1, adding the oxalic acid stock solution into a concentration tank, adjusting the concentration, and preheating for later use;
s2, starting a vacuum pump to pump out air in the evaporative crystallizer, and then starting a stock solution pump to inject the oxalic acid stock solution into the evaporative crystallizer so as to evaporate the solvent in the evaporative crystallizer to perform primary crystallization;
s3, cooling the stock solution after the evaporation step in a cooling crystallizer to ensure that the stock solution is cooled in the cooling crystallizer for secondary crystallization;
s4, feeding the feed liquid after the secondary crystallization into a mother material barrel, discharging the feed liquid into a cooling crystallizer through a reflux pump, and carrying out heat exchange, cooling and crystallization again;
and S5, finally, conveying the feed liquid to a slurry barrel, starting a slurry barrel stirrer for stirring, and opening a discharge valve of the slurry barrel to enable the material to enter a centrifugal machine to separate oxalic acid crystals.
2. The process for the continuous crystallization of oxalic acid according to claim 1, characterized in that: in the S1, the concentration of the oxalic acid stock solution is 18-23%, and the preheating temperature is 70-90 ℃.
3. The process for the continuous crystallization of oxalic acid according to claim 1, characterized in that: in the S2, the evaporation temperature of the evaporation crystallizer is 70-90 ℃, the concentration degree of the stock solution after evaporation is 52-58%, and the temperature is reduced to 45-50 ℃ after evaporation.
4. The process for the continuous crystallization of oxalic acid according to claim 1, characterized in that: in the S2, when the liquid level in the evaporative crystallizer reaches 4-4.5m, the raw liquid is stopped entering.
5. The process for the continuous crystallization of oxalic acid according to claim 1, characterized in that: in the S3, the cooling temperature of the cooling crystallizer is-5 ℃, and the upper-lower difference is 1 ℃.
6. The process for the continuous crystallization of oxalic acid according to claim 1, characterized in that: in S3, when the cooling crystallizer discharges, the raw liquid pump is turned on to continuously feed the raw liquid into the evaporative crystallizer.
7. The process for the continuous crystallization of oxalic acid according to claim 1, characterized in that: in the S4, the continuous heat exchange time is 3.5-4.5h to realize crystallization.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210560678.XA CN114949909A (en) | 2022-05-21 | 2022-05-21 | Continuous crystallization process of oxalic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210560678.XA CN114949909A (en) | 2022-05-21 | 2022-05-21 | Continuous crystallization process of oxalic acid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114949909A true CN114949909A (en) | 2022-08-30 |
Family
ID=82986201
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210560678.XA Pending CN114949909A (en) | 2022-05-21 | 2022-05-21 | Continuous crystallization process of oxalic acid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114949909A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991010637A1 (en) * | 1990-01-09 | 1991-07-25 | Kemira Oy | A process for preparing oxalic acid |
| CN104478693A (en) * | 2014-12-23 | 2015-04-01 | 山东丰元化学股份有限公司 | Preparation method of refined oxalic acid |
| CN108568134A (en) * | 2018-07-23 | 2018-09-25 | 深圳市瑞升华科技股份有限公司 | Cobaltous sulfate evaporation crystallization equipment and technique |
| CN109350990A (en) * | 2018-11-14 | 2019-02-19 | 山东飞扬化工有限公司 | A kind of succinic acid purification system and technique |
| CN110613951A (en) * | 2019-10-08 | 2019-12-27 | 深圳市瑞升华科技股份有限公司 | Evaporation concentration flash evaporation cooling crystallization equipment and process thereof |
-
2022
- 2022-05-21 CN CN202210560678.XA patent/CN114949909A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991010637A1 (en) * | 1990-01-09 | 1991-07-25 | Kemira Oy | A process for preparing oxalic acid |
| CN104478693A (en) * | 2014-12-23 | 2015-04-01 | 山东丰元化学股份有限公司 | Preparation method of refined oxalic acid |
| CN108568134A (en) * | 2018-07-23 | 2018-09-25 | 深圳市瑞升华科技股份有限公司 | Cobaltous sulfate evaporation crystallization equipment and technique |
| CN109350990A (en) * | 2018-11-14 | 2019-02-19 | 山东飞扬化工有限公司 | A kind of succinic acid purification system and technique |
| CN110613951A (en) * | 2019-10-08 | 2019-12-27 | 深圳市瑞升华科技股份有限公司 | Evaporation concentration flash evaporation cooling crystallization equipment and process thereof |
Non-Patent Citations (1)
| Title |
|---|
| 吉林化学工业公司化肥厂编: "《化工过程原理及其处理方法探究》", 北京：化学工业出版社, pages: 236 - 237 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1214981C (en) | Production process of lithium hydroxide monohydrate | |
| CN104788345B (en) | A kind of production method of high-purity hydrochloric acid metformin | |
| CN105668598B (en) | Method for removing sodium oxalate during aluminum oxide production process | |
| WO2022233341A1 (en) | Method for purifying fluoroethylene carbonate and product obtained therefrom | |
| CN111905398A (en) | Process for producing nickel cobalt salt and ammonium salt by continuous crystallization | |
| US11512014B2 (en) | Saline glycerine wastewater treatment system and technology | |
| CN114933288A (en) | High-purity monopotassium phosphate and preparation method thereof | |
| CN103804252A (en) | Methionine crystallization separation system and process for crystallizing separating methionine | |
| CN114949909A (en) | Continuous crystallization process of oxalic acid | |
| CN110803715A (en) | Continuous preparation method of ammonium heptamolybdate | |
| CN113274882B (en) | Ammonium adipate waste liquid recovery method and device based on high-temperature bipolar membrane electrodialysis | |
| CN115849411A (en) | Continuous production process of lithium hydroxide | |
| CN214181868U (en) | Cooling crystallization device of C4-C6 mixed dibasic acid solution | |
| CN115432721A (en) | Process for preparing lithium hydroxide | |
| CN112250613B (en) | Preparation process and device system for ethyl carbazole continuous cooling recrystallization | |
| CN107200312A (en) | A kind of method for preparing nitric acid, potassium fluoborate and potassium nitrate using the fluorine-containing nitric acid that gives up | |
| CN217613030U (en) | Battery-grade manganese sulfate production system | |
| CN112851492A (en) | Method for recovering benzoic acid from sodium benzoate-containing wastewater | |
| CN214861311U (en) | Continuous device for chlorfenapyr crystallization | |
| CN111204778A (en) | Production process of anhydrous sodium sulfite | |
| CN114956987A (en) | Succinic acid re-melting purification and recrystallization process | |
| CN115040890B (en) | Process for purifying and recrystallizing oxalic acid by remelting | |
| CN115463444B (en) | Preparation system and preparation process for preparing ultrapure grade dimethyl carbonate | |
| CN220990762U (en) | Production system for preparing liquid sodium bis (fluorosulfonyl) imide | |
| CN115141095A (en) | Process for re-melting, purifying and recrystallizing adipic acid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220830 |