CN113816339A - Method for preparing anhydrous hydrogen fluoride from sodium fluoride - Google Patents
Method for preparing anhydrous hydrogen fluoride from sodium fluoride Download PDFInfo
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- CN113816339A CN113816339A CN202111192399.4A CN202111192399A CN113816339A CN 113816339 A CN113816339 A CN 113816339A CN 202111192399 A CN202111192399 A CN 202111192399A CN 113816339 A CN113816339 A CN 113816339A
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- fluoride
- hydrogen fluoride
- sodium
- sodium fluoride
- anhydrous hydrogen
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- 238000000034 method Methods 0.000 title claims abstract description 176
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 title claims abstract description 140
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 229910000040 hydrogen fluoride Inorganic materials 0.000 title claims abstract description 87
- 239000011775 sodium fluoride Substances 0.000 title claims abstract description 70
- 235000013024 sodium fluoride Nutrition 0.000 title claims abstract description 70
- 239000007789 gas Substances 0.000 claims abstract description 73
- 238000006243 chemical reaction Methods 0.000 claims abstract description 40
- 239000000047 product Substances 0.000 claims abstract description 30
- 238000009833 condensation Methods 0.000 claims abstract description 28
- 230000005494 condensation Effects 0.000 claims abstract description 28
- 238000005243 fluidization Methods 0.000 claims abstract description 23
- 239000002994 raw material Substances 0.000 claims abstract description 22
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 20
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 20
- 239000002244 precipitate Substances 0.000 claims abstract description 19
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims abstract description 18
- 239000012265 solid product Substances 0.000 claims abstract description 16
- 238000001035 drying Methods 0.000 claims abstract description 15
- 230000001376 precipitating effect Effects 0.000 claims abstract description 15
- 238000007670 refining Methods 0.000 claims abstract description 15
- 238000001914 filtration Methods 0.000 claims abstract description 14
- 239000011780 sodium chloride Substances 0.000 claims abstract description 10
- 239000003513 alkali Substances 0.000 claims abstract description 9
- 238000001556 precipitation Methods 0.000 claims abstract description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 15
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 12
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 claims description 8
- 150000002221 fluorine Chemical class 0.000 claims description 8
- 238000001704 evaporation Methods 0.000 claims description 6
- 230000008020 evaporation Effects 0.000 claims description 6
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 6
- 238000010992 reflux Methods 0.000 claims description 6
- 239000012043 crude product Substances 0.000 claims description 5
- -1 fluoride ions Chemical class 0.000 claims description 5
- 150000004673 fluoride salts Chemical class 0.000 claims description 5
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 4
- 239000001110 calcium chloride Substances 0.000 claims description 4
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 4
- 150000003841 chloride salts Chemical class 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 230000007613 environmental effect Effects 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 238000005485 electric heating Methods 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 12
- 238000000746 purification Methods 0.000 abstract description 7
- 238000002360 preparation method Methods 0.000 abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 6
- 208000005156 Dehydration Diseases 0.000 abstract description 4
- 230000018044 dehydration Effects 0.000 abstract description 4
- 238000006297 dehydration reaction Methods 0.000 abstract description 4
- 238000000926 separation method Methods 0.000 abstract description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 21
- 229910052731 fluorine Inorganic materials 0.000 description 21
- 239000011737 fluorine Substances 0.000 description 21
- 239000002253 acid Substances 0.000 description 17
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 11
- 229910001634 calcium fluoride Inorganic materials 0.000 description 8
- 239000006227 byproduct Substances 0.000 description 7
- FFBHFFJDDLITSX-UHFFFAOYSA-N benzyl N-[2-hydroxy-4-(3-oxomorpholin-4-yl)phenyl]carbamate Chemical compound OC1=C(NC(=O)OCC2=CC=CC=C2)C=CC(=C1)N1CCOCC1=O FFBHFFJDDLITSX-UHFFFAOYSA-N 0.000 description 6
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 6
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 6
- 239000002686 phosphate fertilizer Substances 0.000 description 6
- 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 5
- 238000005265 energy consumption Methods 0.000 description 5
- 239000010436 fluorite Substances 0.000 description 5
- 239000011734 sodium Substances 0.000 description 5
- 229910052708 sodium Inorganic materials 0.000 description 5
- 238000003860 storage Methods 0.000 description 5
- 229910019142 PO4 Inorganic materials 0.000 description 4
- 239000000706 filtrate Substances 0.000 description 4
- 239000011268 mixed slurry Substances 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 4
- 239000010452 phosphate Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 3
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- ABTOQLMXBSRXSM-UHFFFAOYSA-N silicon tetrafluoride Chemical compound F[Si](F)(F)F ABTOQLMXBSRXSM-UHFFFAOYSA-N 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000006115 defluorination reaction Methods 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- BFXAWOHHDUIALU-UHFFFAOYSA-M sodium;hydron;difluoride Chemical compound F.[F-].[Na+] BFXAWOHHDUIALU-UHFFFAOYSA-M 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000005915 ammonolysis reaction Methods 0.000 description 1
- LDDQLRUQCUTJBB-UHFFFAOYSA-O azanium;hydrofluoride Chemical compound [NH4+].F LDDQLRUQCUTJBB-UHFFFAOYSA-O 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 229940104869 fluorosilicate Drugs 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- RHFUXPCCELGMFC-UHFFFAOYSA-N n-(6-cyano-3-hydroxy-2,2-dimethyl-3,4-dihydrochromen-4-yl)-n-phenylmethoxyacetamide Chemical compound OC1C(C)(C)OC2=CC=C(C#N)C=C2C1N(C(=O)C)OCC1=CC=CC=C1 RHFUXPCCELGMFC-UHFFFAOYSA-N 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B7/00—Halogens; Halogen acids
- C01B7/19—Fluorine; Hydrogen fluoride
- C01B7/191—Hydrogen fluoride
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/20—Halides
- C01F11/22—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/26—Magnesium halides
- C01F5/28—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/48—Halides, with or without other cations besides aluminium
- C01F7/50—Fluorides
-
- 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
- Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention discloses a method for preparing anhydrous hydrogen fluoride by using sodium fluoride. The method mainly comprises the working procedures of drying preheating, fluidization conversion, multi-stage condensation, refining and purification, dissolving precipitation, filtering separation and the like, and specifically comprises the following steps: drying and preheating a sodium fluoride raw material by hot air, then performing a fluidization conversion process, reacting the sodium fluoride raw material with preheated hydrogen chloride gas, and performing multi-stage condensation and refining purification processes on the gas generated by the reaction to obtain an anhydrous hydrogen fluoride product; and the solid product is sent to a dissolving and precipitating process, water and chloride are added to dissolve sodium chloride, residual sodium fluoride is converted into precipitate, the villaumite precipitate and the sodium chloride solution are separated through a filtering and separating process, the filtered sodium chloride solution is sent to a chlor-alkali plant, and villaumite can be sold as a product. The invention is a dry method hydrogen fluoride preparation technology, and anhydrous hydrogen fluoride can be obtained without special dehydration treatment.
Description
Technical Field
The invention relates to the field of chemical industry, in particular to a method for preparing anhydrous hydrogen fluoride from sodium fluoride.
Background
The hydrogen fluoride is used as a basic fluorine chemical product and is widely applied to the production of refrigerants, fluorine resins, fluorine-containing intermediates and fine chemicals, and the high-quality hydrogen fluoride can be used as a main raw material of high-end fluoride. At present, the fluorite-sulfuric acid process is the primary method for preparing hydrogen fluoride. However, the storage capacity of fluorite as a strategic resource is very limited and is a non-renewable resource, and the storage capacity of the fluorite with mining value in China is about 3000 ten thousand tons at present, and the fluorite which can be used for acid preparation can be only used for 25 years in China. In contrast, the fluorine content in the raw material phosphate ore for producing the phosphate fertilizer is mostly 3% -4%, the fluorine content is lower, but the storage amount of the phosphate ore is huge, the fluorine storage amount in the phosphate ore with the exploitation value exceeds 100 times of the fluorine storage amount in the fluorite, and in the future that resources are increasingly scarce, the fluorite resources are exhausted, and the fluorine in the phosphate ore can possibly become the only fluorine resource.
In the production process of phosphate fertilizer, fluorine overflows mainly in the form of silicon tetrafluoride and is absorbed by water to form fluosilicic acid. Therefore, fluosilicic acid is a main byproduct in the production of wet-process phosphoric acid, and is mainly used for preparing anhydrous hydrogen fluoride, and inorganic fluorine salts such as sodium fluosilicate, sodium fluoride, ammonium fluosilicate, ammonium hydrogen fluoride and the like. The main methods for preparing anhydrous hydrogen fluoride from fluorosilicic acid, which is a byproduct of phosphate fertilizer, can be classified into direct methods and indirect methods. The direct method is to adopt fluosilicic acid or sodium fluosilicate as a raw material, add concentrated sulfuric acid to react to form hydrogen fluoride, and then obtain anhydrous hydrogen fluoride through dehydration treatment, for example, Chinese patents CN102557043B and CN109574017A adopt sodium fluosilicate as a raw material, add concentrated sulfuric acid to directly react to prepare hydrogen fluoride, and then remove impurity gas silicon tetrafluoride through pressure rectification. However, the disadvantage is that the theoretical conversion of hydrogen fluoride per pass of the decomposition of fluorosilicic acid is only 33.3%, HF and H2The O separation efficiency is also low and,therefore, the material circulation treatment capacity is large, and the fluorine loss of the system is high; to obtain anhydrous hydrogen fluoride, concentrated sulfuric acid is required for dehydration, resulting in the production of a large amount of dilute sulfuric acid having a concentration of about 70%. In addition, hydrogen fluoride can volatilize along with silicon tetrafluoride in the process of decomposing fluosilicic acid by sulfuric acid, so that the requirement on the control of the decomposition process condition is higher. The indirect method is to convert fluosilicic acid into fluorine salt such as ammonium fluosilicate, sodium/potassium fluosilicate and the like, and then to convert the fluosilicic acid salt into hydrogen fluoride by adopting a wet method or a technique combining the wet method and the dry method. The wet process technology is generally a wet process technology for preparing hydrogen fluoride by reacting fluorosilicate with concentrated sulfuric acid, for example, chinese patent CN112897466A adopts a reaction of potassium sulfate and fluorosilicic acid to prepare fluorophosphoric acid and potassium fluorosilicate, and then reacts potassium fluorosilicate with sulfuric acid to prepare hydrogen fluoride. For example, in chinese patent CN106241740B, fluosilicic acid is converted into ammonium fluoride, which is then sprayed into heated concentrated sulfuric acid, and the obtained crude hydrogen fluoride is refined to prepare anhydrous hydrogen fluoride. In fact, this wet process technique still has problems similar to the direct process, and in addition, produces by-products that are difficult to utilize. Therefore, a plurality of inorganic fluorine chemical enterprises develop a technology combining a wet method and a dry method, namely, fluosilicic acid is converted into hydrofluoride through the wet method technology, and the hydrofluoride is prepared into anhydrous hydrogen fluoride through a dry method pyrolysis method. For example, polyfluoro compounds have developed a process for converting fluosilicic acid into sodium bifluoride by a wet method, the sodium bifluoride is prepared into anhydrous hydrogen fluoride by dry pyrolysis, and the byproduct sodium fluoride can be returned to the process for circulation (see Chinese patent CN 102795601B); and for example, the Dingsheng chemical industry prepares calcium fluoride by a wet method technology, the calcium fluoride is hydrolyzed by a fluidization technology to prepare hydrogen fluoride, the product gas is condensed to obtain anhydrous hydrogen chloride, and the solid product calcium oxide obtained by hydrolysis is returned to the working procedure to prepare the calcium fluoride in a circulating way (see Chinese patent CN 105645358A). However, the technical process is too complex, and is difficult to control in the wet process, and the energy consumption of the whole process is high.
Although the process for directly preparing hydrogen fluoride by adopting fluosilicic acid is successfully industrialized in Vanfu (group) Limited liability company, the process is only suitable for enterprises equipped with large-scale common calcium production lines. Therefore, the production process for further producing hydrogen fluoride after the fluosilicic acid is prepared into the fluoride salt which is easy to transport is the best way for comprehensively utilizing the fluosilicic acid, and sodium fluoride is one of the fluoride salts which meet the development requirement. At present, more than 40 sodium fluoride production enterprises exist in China, more than 10 production enterprises with the production scale of more than 5kt/a exist, and the maximum capacity is 10 kt/a. The annual production capacity of domestic sodium fluoride exceeds 10 ten thousand tons, but the annual yield is only about 6 ten thousand tons, and the sodium fluoride is actually in the state of excess capacity. Therefore, there is a need to develop a technical route for converting sodium fluoride into higher added value, such as sodium fluoride to produce anhydrous hydrogen fluoride.
In view of the technology of preparing anhydrous hydrogen fluoride by combining the byproduct fluorine source of the prior phosphate fertilizer, the method also has the following problems: (1) the energy consumption is higher. From the energy consumption of the actual production of preparing anhydrous hydrogen fluoride by the direct method of fluosilicic acid in the currently reported technology, the electricity consumption for producing one ton of anhydrous hydrogen fluoride is about 1030 ℃; the indirect method is subjected to ammonolysis, multi-step drying and high-temperature hydrolysis, and the energy consumption is higher and even not lower than that of the direct method. (2) Fluorine is difficult to be fully utilized. As mentioned above, in the direct method, only 33.3% of fluorine in one way can be converted into hydrogen fluoride theoretically, about 66% of fluorine needs to be returned to the system for circulation, and the conversion rate of fluorine in one way in the actual process may be lower; indirect calcium fluoride hydrolysis is practically thermodynamically limited and is difficult to hydrolyze or completely hydrolyze. (3) The process is complicated. Although the direct method is simple in principle, the direct method involves the working procedures of concentration, reaction, absorption, steam stripping, rectification and the like, and the process flow is still relatively complex; also, the process of the indirect method is very complicated.
Therefore, the invention aims at the problem of preparing anhydrous hydrogen fluoride by using a byproduct fluorine source of a phosphate fertilizer, and the anhydrous hydrogen fluoride is prepared by using sodium fluoride as a raw material and adopting a dry method technology.
Disclosure of Invention
The invention provides a method for preparing anhydrous hydrogen fluoride from sodium fluoride, aiming at solving the problems of preparing the anhydrous hydrogen fluoride from a byproduct fluorine source of a phosphate fertilizer in the prior art, namely, the sodium fluoride and hydrogen chloride gas are subjected to gas-solid reaction, and the obtained crude anhydrous hydrogen fluoride gas is refined to obtain pure anhydrous hydrogen fluoride. The method has the advantages of simple operation, mild reaction conditions and almost no generation of waste residues, waste liquid and waste gas; the invention is a dry method hydrogen fluoride preparation technology, and anhydrous hydrogen fluoride can be obtained without dehydration treatment.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for preparing anhydrous hydrogen fluoride from sodium fluoride, which comprises the following steps: the method comprises the following steps of a drying preheating process 1, a gas preheating process 2, a fluidization conversion process 3, a multi-stage condensation process 4, a refining and purifying process 5, a tail gas treatment process 6, a dissolving and precipitating process 7, a filtering and separating process 8 and the like, and specifically comprises the following steps:
1) sodium fluoride is sent to a drying and preheating process step 1, hot air is introduced to preheat the sodium fluoride raw material, and the dried tail gas is sent to a tail gas treatment process step 6;
2) hydrogen chloride gas is sent to a gas preheating procedure 2 to be preheated;
3) feeding the preheated sodium fluoride into a fluidization conversion process 3, and reacting the preheated sodium fluoride with preheated hydrogen chloride gas to respectively obtain a gaseous product and a solid product;
4) the gaseous product obtained in the fluidization conversion process 3 is sent to a multi-stage condensation process 4, so that the hydrogen fluoride gas is converted into a liquid hydrogen fluoride crude product through multi-stage condensation, and the residual gas enters a tail gas treatment process 6 and is discharged after reaching the standard through environmental protection treatment;
5) sending the liquid hydrogen fluoride crude product obtained in the multistage condensation step 4 into a refining and purifying step 5, and separating hydrogen fluoride from other gases to obtain an anhydrous hydrogen fluoride product; the refined and purified tail gas is sent to a tail gas treatment process 6;
6) sending the solid product obtained in the fluidization conversion process 3 to a dissolving and precipitating process 7 to dissolve the solid product, and adding chloride salt to convert the residual sodium fluoride into fluoride salt precipitate to be separated;
7) and (3) sending the mixture obtained in the dissolving and precipitating step (7) to a filtering and separating step (8) to separate the fluorine salt precipitate from the sodium chloride solution, returning the sodium chloride solution to a chlor-alkali plant, and taking the obtained fluorine salt precipitate as a product for sale.
Preferably, the average particle size of the sodium fluoride powder is 0.05-2.0 mm, and the mass content of NaF is not less than 80%.
Preferably, in the drying and preheating step 1, a multi-stage cyclone or a fluidized bed can be used as a preheater to preheat the sodium fluoride raw material to 200-600 ℃.
Preferably, the gas preheating process 2 can adopt an electric heating or gas hot blast stove for preheating, and the hydrogen chloride gas is preheated to 200-500 ℃.
Preferably, the fluidized bed is used as a reactor in the fluidized conversion process 3, the conversion reaction temperature is 300-600 ℃, and the average residence time of particles is 0.5-4 h.
Preferably, the multistage condensation process 4 adopts a multistage condensation mode, and the lowest condensation temperature is-80 to-50 ℃.
Preferably, the refining and purifying process 6 adopts a sulfuric acid drying-multistage rectification mode, and the rectification conditions are that the number of tower plates is 5-50, the evaporation temperature is 15-25 ℃, the tower top temperature is 10-19 ℃ and the reflux ratio is 1-30.
Preferably, the dissolving and precipitating process 7 adopts one or a combination of more of aluminum chloride, calcium chloride or magnesium chloride, the adding amount is 100-120% of the theoretical amount required by the complete precipitation of the fluoride ions, and the operating temperature is 25-100 ℃.
Compared with the prior report technology, the invention has the following outstanding advantages:
(1) the fluorine element can be completely converted into the hydrogen fluoride, namely the conversion per pass of the fluorine element can reach 100 percent theoretically.
(2) Can obviously reduce energy consumption and shorten the preparation process. The chlorine and the sodium have stronger binding capacity through the gas-solid reaction of the hydrogen chloride gas and the sodium fluoride, so that the rapid and complete conversion can be realized under the condition of lower temperature. In addition, the whole process flow is short, and the anhydrous hydrogen fluoride can be obtained after conversion, dust removal and refining.
(3) The whole process almost has no three wastes discharge, and belongs to a real green anhydrous hydrogen fluoride preparation process. The solid product sodium chloride obtained in the preparation process can circularly enter a chlor-alkali plant after defluorination, and the calcium fluoride obtained by defluorination can be sold as a product. In addition, a small amount of anhydrous hydrogen chloride separated from the purification of the gaseous product can be recycled to the conversion process. Therefore, the whole process almost has no three wastes discharge.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.
FIG. 1 is a schematic flow chart of a method for preparing anhydrous hydrogen fluoride from sodium fluoride according to the present invention.
Detailed Description
The invention is described in further detail below with reference to the figures and the detailed description.
Example 1
Fig. 1 is a schematic flow chart of a method for preparing anhydrous hydrogen fluoride from sodium fluoride according to the invention. With reference to fig. 1, a method for preparing hydrogen fluoride from sodium fluoride comprises a drying preheating process 1, a gas preheating process 2, a fluidization conversion process 3, a multi-stage condensation process 4, a refining and purifying process 5, a tail gas treatment process 6, a dissolving and precipitating process 7, a filtering and separating process 8 and the like, and is specifically carried out according to the following steps:
1) sodium fluoride is sent to a drying and preheating process step 1, hot air is introduced to preheat the sodium fluoride raw material, and the dried tail gas is sent to a tail gas treatment process step 6;
2) hydrogen chloride gas is sent to a gas preheating procedure 2 to be preheated;
3) feeding the preheated sodium fluoride into a fluidization conversion process 3, and reacting the preheated sodium fluoride with preheated hydrogen chloride gas to respectively obtain a gaseous product and a solid product;
4) the gaseous product obtained in the fluidization conversion process 3 is sent to a multi-stage condensation process 4, so that the hydrogen fluoride gas is converted into hydrogen fluoride liquid through multi-stage condensation, and the residual gas enters a tail gas treatment process 6 and is discharged after reaching the standard through environmental protection treatment;
5) sending the liquid hydrogen fluoride crude product obtained in the multistage condensation step 4 into a refining and purifying step 5, and separating hydrogen fluoride from other gases to obtain an anhydrous hydrogen fluoride product; the refined and purified tail gas is sent to a tail gas treatment process 6;
6) sending the solid product obtained in the fluidization conversion process 3 to a dissolving and precipitating process 7 to dissolve the solid product, and adding chloride salt to convert the residual sodium fluoride into fluoride salt precipitate to be separated;
7) and (3) sending the mixture obtained in the dissolving and precipitating step (7) to a filtering and separating step (8) to separate the fluorine salt precipitate from the sodium chloride solution, returning the sodium chloride solution to a chlor-alkali plant, and taking the obtained fluorine salt precipitate as a product for sale.
Example 2
This example uses a method for preparing anhydrous hydrogen fluoride from sodium fluoride as described in example 1. The method comprises the steps of taking 0.05-0.2 mm sodium fluoride with 85.6% of NaF content as a raw material, sending the raw material into a drying preheating process 1 to be subjected to heat exchange with hot air for preheating to 600 ℃, sending the preheated raw material into a fluidization conversion process 3, simultaneously introducing hydrogen chloride gas preheated to 500 ℃ in a gas preheating process 2, allowing the gas to stay in a fluidized bed reactor at 600 ℃ for 0.5h, sending a gaseous product obtained by reaction into a multistage condensation process 4, obtaining crude hydrogen fluoride liquid by adopting a two-stage condensation mode with condensation temperatures of-50 ℃ and-60 ℃, and then sending the crude hydrogen fluoride liquid into a refining purification process 5, wherein the rectification conditions are that the number of rectification is 30, the evaporation temperature is 15 ℃, the tower top temperature is 10 ℃, the reflux ratio is 15, the obtained anhydrous hydrogen fluoride is sent into a product pipeline, and the refined tail gas is sent into a tail gas treatment process 6; and the solid product obtained in the fluidization conversion process 3 enters a dissolving and precipitating process 7, water and calcium chloride are added, the calcium chloride is dissolved at 100 ℃, a small amount of sodium fluoride which is not reacted is converted into calcium fluoride precipitate, then the mixed slurry is sent to a filtering and separating process 8, the calcium fluoride precipitate is separated by filtering, the filtrate can be returned to a chlor-alkali plant, and the calcium fluoride can be sold as a product.
Example 3
This example uses a method for preparing anhydrous hydrogen fluoride from sodium fluoride as described in example 1. The method comprises the steps of taking 0.2-0.3 mm sodium fluoride with 96.3% of NaF content as a raw material, sending the sodium fluoride into a drying preheating process 1 to be subjected to heat exchange with hot air for preheating to 200 ℃, sending the preheated raw material into a fluidization conversion process 3, simultaneously introducing hydrogen chloride gas preheated to 500 ℃ in a gas preheating process 2, allowing the hydrogen chloride gas to stay in a fluidized bed reactor at 400 ℃ for 2.5 hours, sending a gaseous product obtained by reaction into a multistage condensation process 4, condensing at-80 ℃ to obtain a crude hydrogen fluoride liquid, sending the crude hydrogen fluoride liquid into a refining purification process 5, wherein the number of tower plates is 5, the evaporation temperature is 20 ℃, the tower top temperature is 15 ℃, the reflux ratio is 30, sending the obtained anhydrous hydrogen fluoride into a product pipeline, and sending the refined tail gas into a tail gas treatment process 6; the solid product obtained in the fluidization conversion process 3 enters a dissolution precipitation process 7, water and aluminum chloride are added, aluminum chloride is dissolved at 50 ℃, a small amount of unreacted sodium fluoride is converted into aluminum fluoride precipitate, then the mixed slurry is sent to a filtration separation process 8, the aluminum fluoride precipitate is separated by filtration, the filtrate can be returned to a chlor-alkali plant, and the aluminum fluoride can be sold as a product.
Example 4
This example uses a method for preparing anhydrous hydrogen fluoride from sodium fluoride as described in example 1. The method comprises the steps of taking 0.3-0.5 mm sodium fluoride with 80.0% of NaF content as a raw material, sending the raw material into a drying preheating process 1 to be subjected to heat exchange with hot air for preheating to 300 ℃, sending the preheated raw material into a fluidization conversion process 3, simultaneously introducing hydrogen chloride gas preheated to 300 ℃ in a gas preheating process 2, allowing the gas to stay in a fluidized bed reactor for 4.0h at 300 ℃, sending a gaseous product obtained by reaction into a multistage condensation process 4, obtaining crude hydrogen fluoride liquid by adopting a two-stage condensation mode with the condensation temperatures of-80 ℃ and-50 ℃, and then sending the crude hydrogen fluoride liquid into a refining purification process 5, wherein the number of tower plates is 15, the evaporation temperature is 25 ℃, the overhead temperature is 10 ℃, the reflux ratio is 10, the obtained anhydrous hydrogen fluoride is sent into a product pipeline, and the refined tail gas is sent into a tail gas treatment process 6; and the solid product obtained in the fluidization conversion process 3 enters a dissolving and precipitating process 7, water and magnesium chloride are added, magnesium chloride is dissolved at 25 ℃, a small amount of unreacted sodium fluoride is converted into magnesium fluoride precipitate, then the mixed slurry is sent to a filtering and separating process 8, the magnesium fluoride precipitate is filtered and separated, the filtrate can be returned to a chlor-alkali plant, and the magnesium fluoride can be sold as a product.
Example 5
This example uses a method for preparing anhydrous hydrogen fluoride from sodium fluoride as described in example 1. The method comprises the steps of taking sodium fluoride with the thickness of 1.0-2.0 mm and the NaF content of 93.2% as a raw material, sending the sodium fluoride into a drying preheating process 1 to be subjected to heat exchange with hot air and preheated to 250 ℃, sending the preheated raw material into a fluidization conversion process 3, simultaneously introducing hydrogen chloride gas preheated to 500 ℃ in a gas preheating process 2, allowing the hydrogen chloride gas to stay in a fluidized bed reactor for 3.0 hours at 350 ℃, sending a gaseous product obtained by reaction into a multistage condensation process 4, condensing at-50 ℃ to obtain a crude hydrogen fluoride liquid, sending the crude hydrogen fluoride liquid into a refining purification process 5, wherein the number of tower plates is 50, the evaporation temperature is 15 ℃, the tower top temperature is 19 ℃, the reflux ratio is 15, sending the obtained anhydrous hydrogen fluoride into a product pipeline, and sending the refined tail gas into a tail gas treatment process 6; and the solid product obtained in the fluidization conversion process 3 enters a dissolving and precipitating process 7, water and magnesium chloride are added, magnesium chloride is dissolved at 60 ℃, a small amount of unreacted sodium fluoride is converted into magnesium fluoride precipitate, then the mixed slurry is sent to a filtering and separating process 8, the magnesium fluoride precipitate is filtered and separated, the filtrate can be returned to a chlor-alkali plant, and the magnesium fluoride can be sold as a product.
The method can be realized by upper and lower limit values and interval values of intervals of process parameters (such as temperature, time and the like), and embodiments are not listed.
Conventional technical knowledge in the art can be used for the details which are not described in the present invention.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. A method for preparing anhydrous hydrogen fluoride from sodium fluoride, which comprises the following steps: the method comprises a drying preheating process (1), a gas preheating process (2), a fluidization conversion process (3), a multi-stage condensation process (4), a refining and purifying process (5), a tail gas treatment process (6), a dissolving and precipitating process (7) and a filtering and separating process (8), and specifically comprises the following steps:
1) sending the sodium fluoride powder into a drying and preheating process (1), introducing hot air to preheat the sodium fluoride raw material, and sending the dried tail gas into a tail gas treatment process (6);
2) sending hydrogen chloride gas into a gas preheating process (2) to preheat the hydrogen chloride gas;
3) feeding the preheated sodium fluoride into a fluidization conversion process (3), and reacting the preheated sodium fluoride with preheated hydrogen chloride gas to respectively obtain a gaseous product and a solid product;
4) the gaseous product obtained in the fluidization conversion process (3) is sent to a multi-stage condensation process (4), so that the hydrogen fluoride gas is changed into a liquid hydrogen fluoride crude product through multi-stage condensation, and the residual gas enters a tail gas treatment process (6) and is discharged after reaching the standard through environmental protection treatment;
5) sending the liquid hydrogen fluoride crude product obtained in the multistage condensation step (4) into a refining and purifying step (5) to separate hydrogen fluoride from other gases to obtain an anhydrous hydrogen fluoride product; sending the refined and purified tail gas into a tail gas treatment process (6);
6) sending the solid product obtained in the fluidization conversion process (3) to a dissolving and precipitating process (7) to dissolve the solid product, and adding chloride salt to convert the residual sodium fluoride into fluoride salt precipitate to be separated;
7) and (3) sending the mixture obtained in the dissolving and precipitating step (7) to a filtering and separating step (8) to separate the fluorine salt precipitate from the sodium chloride solution, returning the sodium chloride solution to a chlor-alkali plant, and taking the obtained fluorine salt precipitate as a product for sale.
2. The method for preparing anhydrous hydrogen fluoride by using sodium fluoride according to claim 1, wherein the average particle size of the sodium fluoride powder is 0.05-2.0 mm, and the mass content of NaF is not less than 80%.
3. The method for preparing anhydrous hydrogen fluoride from sodium fluoride according to claim 1, wherein the drying and preheating step (1) adopts a multi-stage cyclone or a fluidized bed as a preheater to preheat the sodium fluoride raw material to 200-600 ℃.
4. The method for preparing anhydrous hydrogen fluoride from sodium fluoride according to claim 1, wherein the gas preheating step (2) adopts electric heating or gas hot blast stove for preheating, and hydrogen chloride gas is preheated to 200-500 ℃.
5. The method for preparing anhydrous hydrogen fluoride by using sodium fluoride according to claim 1, wherein the fluidized conversion process (3) adopts a fluidized bed as a reactor, the fluidized conversion reaction temperature is 300-600 ℃, and the average particle residence time is 0.5-4 h.
6. The method for preparing anhydrous hydrogen fluoride by using sodium fluoride as claimed in claim 1, wherein the multistage condensation process (4) adopts a multistage condensation mode, and the lowest condensation temperature is-80 ℃ to-50 ℃.
7. The method for preparing anhydrous hydrogen fluoride from sodium fluoride according to claim 1, wherein the refining and purifying process (6) adopts a sulfuric acid drying-multistage rectification mode, and the rectification conditions are as follows: the number of the tower plates is 5-50, the evaporation temperature is 15-25 ℃, the tower top temperature is 10-19 ℃, and the reflux ratio is 1-30.
8. The method for preparing anhydrous hydrogen fluoride from sodium fluoride according to claim 1, wherein the chloride salt added in the dissolving and precipitating step (7) is one or more of aluminum chloride, calcium chloride and magnesium chloride, the addition amount is 100-120% of the theoretical amount required for complete precipitation of fluoride ions, and the operation temperature is 25-100 ℃.
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