CN117326576A - Method for preparing sodium hexafluorophosphate by gas-solid method and application thereof - Google Patents
Method for preparing sodium hexafluorophosphate by gas-solid method and application thereof Download PDFInfo
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- -1 sodium hexafluorophosphate Chemical compound 0.000 title claims abstract description 199
- 239000007787 solid Substances 0.000 title claims abstract description 108
- 238000000034 method Methods 0.000 title claims abstract description 77
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims abstract description 75
- 239000002798 polar solvent Substances 0.000 claims abstract description 45
- 238000006243 chemical reaction Methods 0.000 claims abstract description 44
- 239000003960 organic solvent Substances 0.000 claims abstract description 42
- OBCUTHMOOONNBS-UHFFFAOYSA-N phosphorus pentafluoride Chemical compound FP(F)(F)(F)F OBCUTHMOOONNBS-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000000047 product Substances 0.000 claims abstract description 35
- 230000008569 process Effects 0.000 claims abstract description 31
- 238000001291 vacuum drying Methods 0.000 claims abstract description 25
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000008247 solid mixture Substances 0.000 claims abstract description 20
- 238000004090 dissolution Methods 0.000 claims abstract description 16
- XGRSAFKZAGGXJV-UHFFFAOYSA-N 3-azaniumyl-3-cyclohexylpropanoate Chemical compound OC(=O)CC(N)C1CCCCC1 XGRSAFKZAGGXJV-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000012043 crude product Substances 0.000 claims abstract description 13
- 229960004711 sodium monofluorophosphate Drugs 0.000 claims abstract description 13
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 12
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910001415 sodium ion Inorganic materials 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 8
- 239000003792 electrolyte Substances 0.000 claims abstract description 5
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 4
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims abstract description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 4
- 239000010452 phosphate Substances 0.000 claims abstract description 4
- 239000000243 solution Substances 0.000 claims description 59
- 238000005406 washing Methods 0.000 claims description 59
- 238000001914 filtration Methods 0.000 claims description 52
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 42
- 239000007789 gas Substances 0.000 claims description 26
- 238000004064 recycling Methods 0.000 claims description 26
- 239000010413 mother solution Substances 0.000 claims description 25
- 239000012046 mixed solvent Substances 0.000 claims description 24
- 239000012535 impurity Substances 0.000 claims description 22
- 229910052757 nitrogen Inorganic materials 0.000 claims description 21
- 238000001035 drying Methods 0.000 claims description 19
- 239000007788 liquid Substances 0.000 claims description 13
- 239000000706 filtrate Substances 0.000 claims description 10
- 239000012141 concentrate Substances 0.000 claims description 8
- 230000035484 reaction time Effects 0.000 claims description 6
- 238000000746 purification Methods 0.000 abstract description 12
- 238000004146 energy storage Methods 0.000 abstract description 5
- 230000001376 precipitating effect Effects 0.000 abstract 2
- 239000002904 solvent Substances 0.000 description 35
- 238000002156 mixing Methods 0.000 description 27
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 15
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 15
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 7
- 229910001416 lithium ion Inorganic materials 0.000 description 7
- 238000000197 pyrolysis Methods 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 239000012065 filter cake Substances 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 239000002912 waste gas Substances 0.000 description 5
- 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 4
- 238000001816 cooling Methods 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000012452 mother liquor Substances 0.000 description 3
- 229910000792 Monel Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229910000856 hastalloy Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000003495 polar organic solvent Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 235000013024 sodium fluoride Nutrition 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- 229910000162 sodium phosphate Inorganic materials 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- KBVUALKOHTZCGR-UHFFFAOYSA-M sodium;difluorophosphinate Chemical compound [Na+].[O-]P(F)(F)=O KBVUALKOHTZCGR-UHFFFAOYSA-M 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D13/00—Compounds of sodium or potassium not provided for elsewhere
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/40—Electric properties
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
Abstract
The invention discloses a method for preparing sodium hexafluorophosphate by a gas-solid method and application thereof. The method comprises the following steps: introducing phosphorus pentafluoride gas into sodium monofluorophosphate solid to perform gas-solid reaction to generate a mixture of sodium hexafluorophosphate and phosphate solid; then adding a polar solvent into the solid mixture for dissolution to obtain a sodium hexafluorophosphate solution and solid filter residues; concentrating the sodium hexafluorophosphate solution, adding an organic solvent, precipitating sodium hexafluorophosphate to obtain a crude product, adding a polar solvent for dissolution to obtain a sodium hexafluorophosphate solution, concentrating, adding the organic solvent, precipitating sodium hexafluorophosphate, and vacuum drying to obtain high-purity sodium hexafluorophosphate; wherein the polar solvent is one of dimethyl carbonate and diethyl carbonate; the organic solvent is one of benzene or toluene. The process adopts a gas-solid method to synthesize sodium hexafluorophosphate, has simple process flow and high product purity after multistage purification, can be used as electrolyte of sodium ion batteries, is applied to the fields of new energy electric vehicles, energy storage and the like, and has wide application prospect.
Description
Technical Field
The invention belongs to the technical field of sodium ion batteries, and particularly relates to a method for preparing sodium hexafluorophosphate by a gas-solid method and application of the method.
Background
In recent years, with the high-speed development of the lithium battery industry, the price of upstream lithium ore raw materials is continuously high, and the high cost of lithium battery materials is gradually an obstacle for transformation of new energy industry, so that the development of a novel secondary battery technology which can be complemented with a lithium ion battery is of great importance. The sodium-electricity resource is abundant, the cost is low, the environment is protected, the lithium-ion battery can be used as a first-choice substitute of the lithium-ion battery, and the lithium-ion battery has wide market prospect and application field.
Compared with a lithium ion battery, the sodium ion battery has higher safety performance, rich sodium resource reserves, easily obtained raw materials and lower cost, but the energy density, capacity and charging and discharging frequency of the sodium ion battery are lower than those of the lithium ion battery, so the sodium ion battery is generally applied to the small-sized energy storage fields such as an energy storage cabinet, an electric motor, an electric tricycle or a mobile phone computer, and the like, and is generally matched with the lithium ion battery in the large-sized energy storage field.
The sodium hexafluorophosphate is taken as a main power source of the sodium ion battery, namely, an electrolyte is also the key point of the research and layout of the current new energy enterprises, and how to prepare the high-purity sodium hexafluorophosphate with low cost is beneficial to promoting the health and rapid development of the sodium ion battery industry and realizing the curve overtaking in the field of new energy batteries.
The Chinese patent application publication No. CN114772614A discloses a preparation method of sodium hexafluorophosphate: sodium hexafluorophosphate is prepared by taking sodium fluoride and phosphorus pentafluoride as raw materials, and the used organic solvent freon is an important greenhouse gas, and can cause irreversible damage to the natural environment.
The Chinese patent application publication No. CN114873577A discloses a preparation method of sodium hexafluorophosphate: the method takes phosphorus pentoxide, hydrogen fluoride and sodium source as raw materials to prepare sodium hexafluorophosphate, the reaction conditions are harsh, and the sodium hexafluorophosphate solution is subjected to heating concentration crystallization, so that partial decomposition of sodium hexafluorophosphate can be caused, and the impurity content is higher.
In conclusion, the existing method for preparing sodium hexafluorophosphate has the defects of harsh process conditions, high pollution of the used raw materials, low purity of the product and the like, so that the method for preparing the high-purity sodium hexafluorophosphate by searching for an efficient and environment-friendly method has epoch-making significance for the development of new energy batteries.
Disclosure of Invention
In view of the defects and shortcomings of the prior art, the invention aims to provide a method for preparing sodium hexafluorophosphate by a gas-solid method and application thereof, and the method has the advantages of simple process flow, high product purity and good granularity, can be used as a sodium ion battery electrolyte, is applied to the fields of new energy electric vehicles and the like, and has wide application market and prospect.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the method for preparing sodium hexafluorophosphate by a gas-solid method comprises the following steps:
s1: introducing phosphorus pentafluoride gas into sodium monofluorophosphate solid to perform gas-solid reaction to generate a mixture of sodium hexafluorophosphate and phosphate solid;
s2: adding a polar solvent into the solid mixture generated in the step S1 to fully dissolve, filtering, washing the obtained filter residue with the polar solvent, and combining the filtrate and the washing liquid to obtain a sodium hexafluorophosphate solution;
s3: concentrating the sodium hexafluorophosphate solution obtained in the step S2, adding an organic solvent, crystallizing and separating out sodium hexafluorophosphate, filtering, washing the obtained filter residues with the organic solvent to obtain a sodium hexafluorophosphate crude product, and combining the filtrate and the washing liquid to obtain a mixed mother solution 1;
s4: adding the sodium hexafluorophosphate crude product obtained in the step S3 into a polar solution for dissolution, and filtering insoluble impurities from the dissolved sodium hexafluorophosphate crude product solution by precise filtration to obtain a sodium hexafluorophosphate solution;
s5: concentrating the sodium hexafluorophosphate solution obtained in the step S4, adding an organic solvent, crystallizing and separating out sodium hexafluorophosphate, filtering, washing the obtained filter residues with the organic solvent to obtain a sodium hexafluorophosphate wet product, and combining the filtrate and the washing liquid to obtain a mixed mother solution 2;
s6: vacuum drying the wet sodium hexafluorophosphate product obtained in the step S5 to obtain a high-purity sodium hexafluorophosphate product, wherein phosphorus pentafluoride is firstly introduced periodically in the vacuum drying process, and then nitrogen is introduced periodically; wherein:
in the S2 and the S4, the polar solvent is one of dimethyl carbonate (DMC) and diethyl carbonate (DEC);
in the S3 and S5, the organic solvent is one of benzene or toluene.
According to the scheme, in the step S1, phosphorus pentafluoride gas is derived from pyrolysis purification of hexafluorophosphate.
According to the scheme, in the S1, the gas-solid reaction temperature is 110-140 ℃.
According to the scheme, in the step S1, the gas-solid reaction time is 11-13 h.
According to the scheme, in the S1, the molar ratio of the sodium monofluorophosphate to the phosphorus pentafluoride in the gas-solid reaction is 1: (1.15-1.25).
According to the scheme, in the step S1, the gas-solid reaction kettle is connected in series in two stages, and the material is one of stainless steel, hastelloy or Monel.
According to the scheme, in the step S2, the adding amount of the polar solvent for dissolution is 3-5 times of that of the solid mixture, and the adding amount of the polar solvent for washing is 0.5-1 time of that of the solid mixture; in the step S4, the addition amount of the polar solvent is 5-8 times of the crude sodium hexafluorophosphate.
According to the scheme, in the S3 and the S5, the concentration temperature is 40-50 ℃, and the pressure is-0.04 to-0.06 MPa.
According to the scheme, in the step S3, the sodium hexafluorophosphate solution is concentrated to 28-33%; in the step S5, the sodium hexafluorophosphate solution is concentrated to 28-33%. Can avoid precipitation of sodium hexafluorophosphate in the concentration process, and if sodium hexafluorophosphate is precipitated in the concentration process, impurities are mixed and grains are not good.
According to the scheme, in the S3 and the S5, the adding amount of the organic solvent added after concentration is 3-5 times of that of the sodium hexafluorophosphate concentrated solution, and the adding amount of the organic solvent for washing is 2-3 times of that of the sodium hexafluorophosphate concentrated solution.
According to the above scheme, in the step S6, the conditions for vacuum drying the wet sodium hexafluorophosphate product are as follows: the drying temperature is 85-95 ℃ and the drying time is as follows: 12-15 h, drying negative pressure is as follows: -0.085 to-0.090 MPa.
According to the above scheme, in the step S6, phosphorus pentafluoride is periodically introduced first and then nitrogen is periodically introduced during the vacuum drying process.
According to the scheme, in the S6, the purity of the obtained high-purity sodium hexafluorophosphate reaches more than 99.95%.
According to the above scheme, the metal impurity ions (including but not limited to Fe, K, na, ca, cd, cr, cu, mg, ni, pb, zn, as) in the sodium hexafluorophosphate are reduced to below 5 ppm.
According to the scheme, the recovered polar solvent generated by concentration in the step S3 is applied to the dissolving step of the step S2; the mixed solvent generated by filtering and washing in the step S3 is concentrated and separated to obtain a polar solvent and an organic solvent, the polar solvent is recycled to the dissolving and filtering washing step of the step S2, and the organic solvent is recycled to the concentrating and crystallizing step of the step S3; the recovered polar solvent generated by concentration in the step S5 is applied to the dissolving step of the step S2 or the step S4; and S5, concentrating and separating the mixed solvent generated by filtering, washing and washing to obtain a polar solvent and an organic solvent, recycling the polar solvent to the dissolving process of S2 or S4, and recycling the organic solvent to the concentrating and crystallizing process of S3.
The scheme provides application of high-purity sodium hexafluorophosphate prepared by a gas-solid method as sodium ion battery electrolyte in new energy batteries.
The invention has the following beneficial effects:
1. according to the invention, a gas-solid method is adopted for the first time, phosphorus pentafluoride and sodium monofluorophosphate are used as raw materials for reaction to obtain sodium hexafluorophosphate, and impurities in the obtained product mainly comprise sodium phosphate, monofluoride, sodium difluorophosphate and the like, and various metal impurities are complex in types, so that trace levels are difficult to achieve through a conventional purification method; according to the invention, two different solvents of polar solvent and organic solvent are adopted to act synergistically, and impurities are dissolved by polar solvent dissolution products and organic solvent, so that the products and the impurities are dissolved and washed and filtered twice in a bidirectional way, insoluble substances and metal ion impurities in sodium hexafluorophosphate can be effectively removed, the impurities in electronic grade target products are removed to trace levels, the product purity is high and reaches more than 99.95%, the index accords with the electronic grade product standard, and the method can be applied to industries such as new energy batteries, energy storage and the like.
2. And the sodium hexafluorophosphate wet product is dried in vacuum, and solvent residues are periodically removed by utilizing phosphorus pentafluoride gas protection and nitrogen purging to ensure the quality index of sodium hexafluorophosphate products.
3. Furthermore, filtrate, washing liquid and concentrated recovery liquid generated in the purification process can be recycled, and impurities enriched in the process can be effectively discharged out of the system through precise filtration, so that the enrichment of impurities caused by recycling of mother liquor is avoided; the invention combines the purification process and the solvent recovery and reuse, reduces the consumption of the solvent, generates less three wastes, is environment-friendly and has low cost and industrial application prospect.
Drawings
FIG. 1 is a flow chart of a gas-solid method for preparing sodium hexafluorophosphate in the embodiment of the invention.
Detailed Description
The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.
The embodiment of the invention provides a method for preparing sodium hexafluorophosphate by a gas-solid method, which comprises the following steps:
s1: introducing phosphorus pentafluoride gas into sodium monofluorophosphate solid to perform gas-solid reaction to generate a mixture of sodium hexafluorophosphate and phosphate solid;
s2: adding a polar solvent into the solid mixture generated in the step S1 to fully dissolve, filtering, washing the obtained filter residue with the polar solvent, and combining the filtrate and the washing liquid to obtain a sodium hexafluorophosphate solution;
s3: concentrating the sodium hexafluorophosphate solution obtained in the step S2, adding an organic solvent, crystallizing and separating out sodium hexafluorophosphate, filtering, washing the obtained filter residues with the organic solvent to obtain a sodium hexafluorophosphate crude product, and combining the filtrate and the washing liquid to obtain a mixed mother solution 1;
s4: adding the sodium hexafluorophosphate crude product obtained in the step S3 into a polar solution for dissolution, and filtering insoluble impurities from the dissolved sodium hexafluorophosphate crude product solution by precise filtration to obtain a sodium hexafluorophosphate solution;
s5: concentrating the sodium hexafluorophosphate solution obtained in the step S4, adding an organic solvent, crystallizing and separating out sodium hexafluorophosphate, filtering, washing the obtained filter residues with the organic solvent to obtain a sodium hexafluorophosphate wet product, and combining the filtrate and the washing liquid to obtain a mixed mother solution 2;
s6: vacuum drying the wet sodium hexafluorophosphate product obtained in the step S5 to obtain a high-purity sodium hexafluorophosphate product, wherein phosphorus pentafluoride is firstly introduced periodically in the vacuum drying process, and then nitrogen is introduced periodically; wherein:
in the steps S2 and S4, the polar solvent is one of dimethyl carbonate (DMC) and diethyl carbonate (DEC);
in the steps S3 and S5, the organic solvent is one of benzene and toluene.
In one embodiment, in the step S1, the phosphorus pentafluoride gas is derived from pyrolysis purification of hexafluorophosphate.
In one embodiment, in the step S1, the gas-solid reaction temperature is 110-140 ℃ and the reaction time is 11-13 h.
In one embodiment, in the step S1, a molar ratio of the sodium monofluorophosphate to the phosphorus pentafluoride in the gas-solid reaction is 1: (1.15-1.25).
In one embodiment, in the step S1, the gas-solid reaction kettle is connected in series in two stages, and the material is one of stainless steel, hastelloy or monel.
In one embodiment, in the step S2, the adding amount of the polar solvent for dissolution is 3-5 times that of the solid mixture, and the adding amount of the polar solvent for washing is 0.5-1 times that of the solid mixture; in the step S4, the addition amount of the polar solvent is 5-8 times of the crude sodium hexafluorophosphate product.
In one embodiment, in the steps S3 and S5, the concentration temperature is 40-50 ℃ and the pressure is-0.04 to-0.06 MPa.
In one embodiment, in the step S3, the sodium hexafluorophosphate solution is concentrated to 28-33%; in the step S5, the sodium hexafluorophosphate solution is concentrated to 28-33%.
In one embodiment, in the steps S3 and S5, the addition amount of the organic solvent is 3 to 5 times that of the sodium hexafluorophosphate concentrate, and the addition amount of the washing organic solvent is 2 to 3 times that of the sodium hexafluorophosphate concentrate.
In one embodiment, in steps S3-S5, the multi-stage purification is effective to reduce metal impurity ions (including but not limited to Fe, K, na, ca, cd, cr, cu, mg, ni, pb, zn, as) in sodium hexafluorophosphate to less than 5 ppm.
In one embodiment, in the step S6, the drying temperature of the wet sodium hexafluorophosphate product is 85-95 ℃ and the drying time is: 12-15 h, drying negative pressure is as follows: -0.085 to-0.090 MPa; in the drying mode, phosphorus pentafluoride is firstly and periodically introduced in the vacuum drying process, and then nitrogen is periodically introduced.
In one embodiment, in the step S6, the purity of the obtained sodium hexafluorophosphate is up to 99.95%.
In one embodiment, the recovered polar solvent generated by concentration in the step S3 is applied to the dissolving step S2; the mixed solvent generated by filtering and washing in the step S3 is concentrated and separated to obtain a polar solvent and an organic solvent, the polar solvent is recycled to the dissolving and filtering washing step of the step S2, and the organic solvent is recycled to the concentrating and crystallizing step of the step S3; the recovered polar solvent generated by concentration in the step S5 is applied to the dissolving step of the step S2 or the step S4; and S5, concentrating and separating the mixed solvent generated by filtering, washing and washing to obtain a polar solvent and an organic solvent, recycling the polar solvent to the dissolving process of S2 or S4, and recycling the organic solvent to the concentrating and crystallizing process of S3.
The following are specific examples.
Example 1:
provided is a method for preparing sodium hexafluorophosphate by a gas-solid method, comprising the following steps:
s1: 923.52g of sodium monofluorophosphate solid is weighed and evenly mixed in a No. 1 gas-solid reaction kettle and a No. 2 gas-solid reaction kettle, the temperature is raised to 130 ℃, the gas-solid reaction kettle rotates at a speed of 4-5 r/min, 1000.00g of phosphorus pentafluoride generated by pyrolysis and purification of hexafluorophosphate is introduced into the No. 1 gas-solid reaction kettle through a shaft side to react with the solid, the reaction time is 13h, excessive phosphorus pentafluoride gas continuously enters the No. 2 gas-solid reaction kettle to react, and waste gas is absorbed by tail gas to reach the standard and is discharged.
S2: 1365.68g of solid mixture generated by the gas-solid reaction of S1 is cooled, 5640.26g of DEC solvent is added for complete dissolution, 903.94g of filter cake is obtained by filtration, and 723.15g of DEC solvent is added for washing. And mixing the washing solution and the filtering mother solution uniformly to obtain a sodium hexafluorophosphate solution.
S3: concentrating the sodium hexafluorophosphate solution obtained in the step S2 at 50 ℃ and under the pressure of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, and recycling 4867.19g DEC recovered solvent to the solid mixture dissolving step. Adding 2470.27g of benzene into 1964.76g of sodium hexafluorophosphate concentrate, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 615.63g of sodium hexafluorophosphate solid and 3819.41g of mixed solvent 1, adding 1119.32g of benzene into the sodium hexafluorophosphate solid to wash to obtain crude sodium hexafluorophosphate, mixing the washing solution and the mixed solvent to obtain mixed mother solution 1, recycling the polar solvent and the organic solvent from the mixed mother solution 1, and dissolving in S2 and concentrating S3.
S4: and (3) adding 3376.95g of DEC solvent into the sodium hexafluorophosphate crude product obtained in the step (S3), dissolving and mixing uniformly, and filtering insoluble impurities by precise filtration to obtain a sodium hexafluorophosphate solution.
S5: concentrating the sodium hexafluorophosphate solution obtained in the step S4 under the temperature condition of 50 ℃ and the pressure condition of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, recycling 2145.69g DEC solvent to the dissolving process, adding 2316.48g fresh benzene into 1846.88g sodium hexafluorophosphate concentrated solution, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 578.69g sodium hexafluorophosphate solid and 3584.67g mixed solvent 2, adding 1115.29g benzene into the sodium hexafluorophosphate solid to wash to obtain sodium hexafluorophosphate wet product, mixing the washing solution and the mixed solvent to obtain mixed mother solution 2, recycling the mixed mother solution 2 to the step S4 for dissolving and concentrating the S3 respectively.
S6: vacuum drying the sodium hexafluorophosphate wet product obtained in the step S5 for 14 hours at the temperature of 90 ℃ and the pressure of-0.088 MPa, wherein phosphorus pentafluoride is periodically introduced in the vacuum drying process, and then nitrogen is periodically introduced, specifically: periodically introducing phosphorus pentafluoride gas for 10min every 2h under the protection of phosphorus pentafluoride gas for the first 8h, and carrying out vacuum drying for 1h and 50min; and periodically replacing nitrogen for 6 hours, periodically introducing nitrogen for 10 minutes every 1 hour, and drying in vacuum for 50 minutes. After the drying, the mixture was cooled to room temperature to obtain 521.08g of a sodium hexafluorophosphate finished product with a purity of 99.95%. The metal impurity ions (such as Fe, K, na, ca, cd, cr, cu, mg, ni, pb, zn, as and the like) in the sodium hexafluorophosphate can be reduced to below 5 ppm.
Example 2:
provided is a method for preparing sodium hexafluorophosphate by a gas-solid method, comprising the following steps:
s1: 1847.04g of sodium monofluorophosphate solid is weighed and evenly mixed in a No. 1 gas-solid reaction kettle and a No. 2 gas-solid reaction kettle, the temperature is raised to 130 ℃, the gas-solid reaction kettle rotates at a speed of 4-5 r/min, 2000.00g of phosphorus pentafluoride produced by pyrolysis and purification of hexafluorophosphate is introduced into the No. 1 gas-solid reaction kettle through a shaft side to react with the solid, the reaction time is 13h, excessive phosphorus pentafluoride gas continuously enters the No. 2 gas-solid reaction kettle to react, and waste gas is absorbed by tail gas to reach the standard and is discharged.
S2: 2714.24g of solid mixture generated by the gas-solid reaction of S1 is cooled, 11508.39g of DEC solvent is added for complete dissolution, 1814.11g of filter cake is obtained by filtration, and 1451.29g of DEC solvent is added for washing. And mixing the washing solution and the filtering mother solution uniformly to obtain a sodium hexafluorophosphate solution.
S3: concentrating the sodium hexafluorophosphate solution obtained in the step S2 at 50 ℃ and under the pressure of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, and recycling 10019.69g DEC recovered solvent to the solid mixture dissolving step. Adding 4995.93g of benzene into 3853.45g of sodium hexafluorophosphate concentrate, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 1207.41g of sodium hexafluorophosphate solid and 7641.97g of mixed solvent 1, adding 2337.99g of benzene into the sodium hexafluorophosphate solid to wash to obtain crude sodium hexafluorophosphate, mixing the washing solution and the mixed solvent to obtain mixed mother solution 1, recycling the polar solvent and the organic solvent from the mixed mother solution 1, and dissolving in S2 and concentrating S3.
S4: and (3) adding 6721.02g of DEC solvent into the sodium hexafluorophosphate crude product obtained in the step (S3), dissolving and mixing uniformly, and filtering insoluble impurities by precise filtration to obtain a sodium hexafluorophosphate solution.
S5: concentrating the sodium hexafluorophosphate solution obtained in the step S4 under the temperature condition of 50 ℃ and the pressure condition of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, recycling 4306.19g DEC solvent to the dissolving process, adding 4630.65g fresh benzene into 3622.24g sodium hexafluorophosphate concentrated solution, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 1134.97g sodium hexafluorophosphate solid and 7117.92g mixed solvent 2, adding 2208.03g benzene into the sodium hexafluorophosphate solid to wash to obtain sodium hexafluorophosphate wet product, mixing the washing solution and the mixed solvent to obtain mixed mother solution 2, recycling the mixed mother solution 2 to the step S4 for dissolving and concentrating the S3 respectively.
S6: vacuum drying the sodium hexafluorophosphate wet product obtained in the step S5 for 14 hours at the temperature of 90 ℃ and the pressure of-0.088 MPa, wherein phosphorus pentafluoride is periodically introduced in the vacuum drying process, and then nitrogen is periodically introduced, specifically: periodically introducing phosphorus pentafluoride gas for 10min every 2h under the protection of phosphorus pentafluoride gas for the first 8h, and carrying out vacuum drying for 1h and 50min; and periodically replacing nitrogen for 6 hours, periodically introducing nitrogen for 10 minutes every 1 hour, and drying in vacuum for 50 minutes. After the drying, the mixture was cooled to room temperature to obtain 1021.98g of a sodium hexafluorophosphate finished product with a purity of 99.95%. The metal impurity ions (such as Fe, K, na, ca, cd, cr, cu, mg, ni, pb, zn, as and the like) in the sodium hexafluorophosphate can be reduced to below 5 ppm.
Example 3:
provided is a method for preparing sodium hexafluorophosphate by a gas-solid method, comprising the following steps:
s1: 4617.60g of sodium monofluorophosphate solid is weighed and evenly mixed in a No. 1 gas-solid reaction kettle and a No. 2 gas-solid reaction kettle, the temperature is raised to 130 ℃, the gas-solid reaction kettle rotates at a speed of 4-5 r/min, 5000.00g of phosphorus pentafluoride generated by pyrolysis and purification of hexafluorophosphate is introduced into the No. 1 gas-solid reaction kettle through a shaft side to react with the solid, the reaction time is 13h, excessive phosphorus pentafluoride gas continuously enters the No. 2 gas-solid reaction kettle to react, and waste gas is absorbed by tail gas to reach the standard and is discharged.
S2: 6870.00g of solid mixture generated by the gas-solid reaction of S1 is cooled, 27823.52g of DEC solvent is added for complete dissolution, 4504.55g of filter cake is obtained by filtration, and 3603.64g of DEC solvent is added for washing. And mixing the washing solution and the filtering mother solution uniformly to obtain a sodium hexafluorophosphate solution.
S3: concentrating the sodium hexafluorophosphate solution obtained in the step S2 at 50 ℃ and under the pressure of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, and recycling 23818.57g DEC recovered solvent to the solid mixture dissolving step. Adding 12221.64g of benzene into 10008.66g of sodium hexafluorophosphate concentrate, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 3136.05g of sodium hexafluorophosphate solid and 19094.25g of mixed solvent 1, adding 5701.91g of benzene into the sodium hexafluorophosphate solid to wash to obtain crude sodium hexafluorophosphate, mixing the washing solution and the mixed solvent to obtain mixed mother solution 1, recycling the polar solvent and the organic solvent from the mixed mother solution 1, and dissolving in S2 and concentrating S3.
S4: and (3) adding 17004.71g of DEC solvent into the sodium hexafluorophosphate crude product obtained in the step (S3), dissolving and mixing uniformly, and filtering insoluble impurities by precise filtration to obtain a sodium hexafluorophosphate solution.
S5: concentrating the sodium hexafluorophosphate solution obtained in the step S4 under the temperature condition of 50 ℃ and the pressure condition of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, recycling 10732.62g DEC solvent to the dissolving process, adding 11516.70g fresh benzene into 9408.14g sodium hexafluorophosphate concentrated solution, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 2947.89g sodium hexafluorophosphate solid and 17976.96g mixed solvent 2, adding 5895.77g benzene into the sodium hexafluorophosphate solid to wash to obtain sodium hexafluorophosphate wet product, mixing the washing solution and the mixed solvent to obtain mixed mother solution 2, recycling the mixed mother solution 2 to the step S4 for dissolving and concentrating the S3 respectively.
S6: vacuum drying the sodium hexafluorophosphate wet product obtained in the step S5 for 14 hours at the temperature of 90 ℃ and the pressure of-0.088 MPa, wherein phosphorus pentafluoride is periodically introduced in the vacuum drying process, and then nitrogen is periodically introduced, specifically: periodically introducing phosphorus pentafluoride gas for 10min every 2h under the protection of phosphorus pentafluoride gas for the first 8h, and carrying out vacuum drying for 1h and 50min; and periodically replacing nitrogen for 6 hours, periodically introducing nitrogen for 10 minutes every 1 hour, and drying in vacuum for 50 minutes. After the drying, the mixture was cooled to room temperature to obtain 2654.16g of a sodium hexafluorophosphate finished product with a purity of 99.96%. The metal impurity ions (such as Fe, K, na, ca, cd, cr, cu, mg, ni, pb, zn, as and the like) in the sodium hexafluorophosphate can be reduced to below 5 ppm.
Comparative example 1:
s1, weighing 1385.28g of sodium monofluorophosphate solid in a 1# gas-solid reaction kettle and a 2# gas-solid reaction kettle, uniformly mixing, heating to 130 ℃, rotating the gas-solid reaction kettle at a speed of 4-5 r/min, introducing 1500.00g of phosphorus pentafluoride generated by pyrolysis purification of hexafluorophosphate into the 1# gas-solid reaction kettle through a shaft side to react with the solid for 13h, and continuously introducing excessive phosphorus pentafluoride gas into the 2# gas-solid reaction kettle to react, wherein waste gas is absorbed by tail gas and discharged up to the standard.
S2, cooling 2030.28g of solid mixture generated by the gas-solid reaction, adding 8324.15g of DEC solvent for full primary dissolution, filtering to obtain 1362.55g of filter cake, and adding 1090.04g of DEC solvent for washing. Mixing the washing liquid and the filtering mother liquor, concentrating until the concentration of sodium hexafluorophosphate is about 30% under the temperature condition of 50 ℃ and the pressure of-0.06 MPa, recycling 8383.91g of DEC solvent to the solid mixture dissolving process, adding 3543.01g of benzene into 2866.09g of sodium hexafluorophosphate concentrate, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in benzene solvent, filtering to obtain 898.04g of sodium hexafluorophosphate solid and 5511.06g of mixed solvent, adding 1714.44g of benzene into the sodium hexafluorophosphate solid for washing, mixing the washing liquid and the mixed solvent for recycling, and vacuum drying the sodium hexafluorophosphate solid for 14h under the temperature condition of 90 ℃ and the pressure of-0.088 MPa, wherein phosphorus pentafluoride is periodically introduced in the vacuum drying process, and then nitrogen is periodically introduced, specifically: periodically introducing phosphorus pentafluoride gas for 10min every 2h under the protection of phosphorus pentafluoride gas for the first 8h, and carrying out vacuum drying for 1h and 50min; and periodically replacing nitrogen for 6 hours, periodically introducing nitrogen for 10 minutes every 1 hour, and drying in vacuum for 50 minutes. After drying, cooling to room temperature to obtain 762.80g of sodium hexafluorophosphate finished product with purity of 99.60%, wherein the purity does not accord with the quality index in the application process of the sodium battery.
Comparative example 2:
s1, weighing 2770.56g of sodium monofluorophosphate solid in a 1# gas-solid reaction kettle and a 2# gas-solid reaction kettle, uniformly mixing, heating to 130 ℃, rotating the gas-solid reaction kettle at a speed of 4-5 r/min, introducing 3000.00g of phosphorus pentafluoride generated by pyrolysis purification of hexafluorophosphate into the 1# gas-solid reaction kettle through a shaft side to react with the solid for 13h, and continuously introducing excessive phosphorus pentafluoride gas into the 2# gas-solid reaction kettle to react, wherein waste gas is discharged after tail gas absorption reaching the standard.
S2, cooling 4060.56g of solid mixture generated by the gas-solid reaction, adding 16688.91g of acetonitrile solvent for full dissolution, filtering to obtain 2834.72g of filter cake, and adding 2267.78g of acetonitrile solvent for washing. The washing solution and the filtration mother liquor are mixed evenly, concentrated to about 30% of sodium hexafluorophosphate under the temperature condition of 50 ℃ and the pressure condition of minus 0.06MPa, and 17068.48g of acetonitrile solvent produced is recycled to the solid mixture dissolving process.
And S3, adding 7073.26g of dichloromethane into 5721.87g of sodium hexafluorophosphate concentrated solution, fully and uniformly mixing, separating out sodium hexafluorophosphate solid according to the solubility curve of sodium hexafluorophosphate in dichloromethane solvent, filtering to obtain 1621.20g of sodium hexafluorophosphate solid and 11173.93g of mixed solvent 1, washing the sodium hexafluorophosphate solid with 2947.63g of dichloromethane, mixing the washing solution and the mixed solvent to obtain mixed mother solution 1, recycling the mixed mother solution 1 to S2 for dissolution and S3 for concentration respectively.
And S4, adding 8907.49g of acetonitrile solvent into the obtained sodium hexafluorophosphate solid to dissolve and mix uniformly, and filtering insoluble impurities by precise filtration to obtain sodium hexafluorophosphate solution.
S5: concentrating the sodium hexafluorophosphate solution obtained in the step S4 at 50 ℃ under the pressure of minus 0.06MPa until the concentration of the sodium hexafluorophosphate is about 30%, recycling 5665.10g of acetonitrile solvent to a dissolving process, adding 6012.27g of fresh dichloromethane into 4863.59g of sodium hexafluorophosphate concentrated solution, fully and uniformly mixing to separate out sodium hexafluorophosphate solid, filtering to obtain 1378.02g of sodium hexafluorophosphate solid and 9497.84g of mixed solvent 2, adding 2505.48g of dichloromethane into the sodium hexafluorophosphate solid for washing, mixing and recycling the washing solution and the mixed solvent to obtain mixed mother solution 2, recycling the mixed mother solution 2 into the step S4 for dissolving and concentrating the step S3 after recycling the polar solvent and the organic solvent.
S6: the sodium hexafluorophosphate solid is dried for 14h under the temperature condition of 90 ℃ and the pressure condition of minus 0.088MPa, wherein phosphorus pentafluoride is periodically introduced in the vacuum drying process, and then nitrogen is periodically introduced, and the method specifically comprises the following steps: periodically introducing phosphorus pentafluoride gas for 10min every 2h under the protection of phosphorus pentafluoride gas for the first 8h, and carrying out vacuum drying for 1h and 50min; and periodically replacing nitrogen for 6 hours, periodically introducing nitrogen for 10 minutes every 1 hour, and drying in vacuum for 50 minutes. After drying, cooling to room temperature to obtain 1240.71g of sodium hexafluorophosphate finished product with purity of 98.90%, wherein the purity does not accord with the quality index in the application process of the sodium battery.
The foregoing is merely illustrative of the preferred embodiments of this invention, and it will be appreciated that numerous modifications and variations can be made to the invention as described above without departing from the spirit of the invention, and it is intended that such modifications and variations be regarded as a matter of scope of the invention.
Claims (10)
1. A method for preparing sodium hexafluorophosphate by a gas-solid method, which is characterized by comprising the following steps:
s1: introducing phosphorus pentafluoride gas into sodium monofluorophosphate solid to perform gas-solid reaction to generate a mixture of sodium hexafluorophosphate and phosphate solid;
s2: adding a polar solvent into the solid mixture generated in the step S1 to fully dissolve, filtering, washing the obtained filter residue with the polar solvent, and combining the filtrate and the washing liquid to obtain a sodium hexafluorophosphate solution;
s3: concentrating the sodium hexafluorophosphate solution obtained in the step S2, adding an organic solvent, crystallizing and separating out sodium hexafluorophosphate, filtering, washing the obtained filter residues with the organic solvent to obtain a sodium hexafluorophosphate crude product, and combining the filtrate and the washing liquid to obtain a mixed mother solution 1;
s4: adding the sodium hexafluorophosphate crude product obtained in the step S3 into a polar solution for dissolution, and filtering insoluble impurities from the dissolved sodium hexafluorophosphate crude product solution by precise filtration to obtain a sodium hexafluorophosphate solution;
s5: concentrating the sodium hexafluorophosphate solution obtained in the step S4, adding an organic solvent, crystallizing and separating out sodium hexafluorophosphate, filtering, washing the obtained filter residues with the organic solvent to obtain a sodium hexafluorophosphate wet product, and combining the filtrate and the washing liquid to obtain a mixed mother solution 2;
s6: vacuum drying the wet sodium hexafluorophosphate product obtained in the step S5 to obtain a high-purity sodium hexafluorophosphate product, wherein phosphorus pentafluoride is firstly introduced periodically in the vacuum drying process, and then nitrogen is introduced periodically; wherein:
in the S2 and the S4, the polar solvent is one of dimethyl carbonate and diethyl carbonate;
in the S3 and S5, the organic solvent is one of benzene or toluene.
2. The method according to claim 1, wherein in S1, the gas-solid reaction temperature is 110-140 ℃ and the reaction time is 11-13 h; the molar ratio of the sodium monofluorophosphate to the phosphorus pentafluoride in the gas-solid reaction is 1: (1.15-1.25).
3. The method according to claim 1, wherein in S2, the addition amount of the polar solvent for dissolution is 3 to 5 times that of the solid mixture, and the addition amount of the polar solvent for washing is 0.5 to 1 time that of the solid mixture; in the step S4, the addition amount of the polar solvent is 5-8 times of the crude sodium hexafluorophosphate.
4. The method according to claim 1, wherein in S3 and S5, the concentration temperature is 40-50 ℃ and the pressure is-0.04 to-0.06 MPa.
5. The method according to claim 1, wherein in S3, the sodium hexafluorophosphate solution is concentrated to 28 to 33%; in the step S5, the sodium hexafluorophosphate solution is concentrated to 28-33%.
6. The method according to claim 1, wherein in S3 and S5, the organic solvent added after concentration is 3 to 5 times the amount of the sodium hexafluorophosphate concentrate, and the organic solvent added for washing is 2 to 3 times the amount of the sodium hexafluorophosphate concentrate.
7. The method according to claim 1, wherein in S6, the vacuum drying temperature of the wet sodium hexafluorophosphate product is 85 to 95 ℃ and the drying time is: 12-15 h, drying negative pressure is as follows: -0.085 to-0.090 MPa.
8. The method according to claim 1, wherein in S6, the purity of the obtained high-purity sodium hexafluorophosphate is 99.95% or more.
9. The method according to claim 1, wherein the recovered polar solvent produced by concentration in S3 is applied to the dissolution step of S2; the mixed solvent generated by filtering and washing in the step S3 is concentrated and separated to obtain a polar solvent and an organic solvent, the polar solvent is recycled to the dissolving and filtering washing step of the step S2, and the organic solvent is recycled to the concentrating and crystallizing step of the step S3; the recovered polar solvent generated by concentration in the step S5 is applied to the dissolving step of the step S2 or the step S4; and S5, concentrating and separating the mixed solvent generated by filtering, washing and washing to obtain a polar solvent and an organic solvent, recycling the polar solvent to the dissolving process of S2 or S4, and recycling the organic solvent to the concentrating and crystallizing process of S3.
10. Use of the high-purity sodium hexafluorophosphate prepared by the method for preparing sodium hexafluorophosphate by the gas-solid method according to any one of claims 1-9 as electrolyte of sodium ion batteries in new energy batteries.
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| CN117936894A (en) * | 2024-03-25 | 2024-04-26 | 新乡意盛科技有限公司 | Efficient preparation method of electrolyte for battery |
| WO2025066595A1 (en) * | 2023-09-27 | 2025-04-03 | 湖北九宁化学科技有限公司 | Method for preparing sodium hexafluorophosphate by gas-solid process, and use of same |
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