72results about "Lithium hexafluorophosphate" patented technology

The present invention provides a synthesis system and a synthesis method for lithium hexafluorophosphate. The synthesis system comprises a gas-liquid reaction kettle and a built-in microbubble generation unit provided in the gas-liquid reaction kettle; a material inlet and a gas inlet are formed in the side wall of the gas-liquid reaction kettle; the built-in microbubble generation unit comprises a first microbubble generator and a second microbubble generator, the first microbubble generator is provided below the liquid level in the gas-liquid reaction kettle and connected to the material inlet, and the second microbubble generator is provided at the bottom end of the gas-liquid reaction kettle and connected to the gas inlet; a plurality of layers of perforated plates are successively provided in the gas-liquid reaction kettle from top to bottom; through holes of said perforated plates are staggered, and said perforated plates are provided between the first microbubble generator and the second microbubble generator. The synthesis system of the present invention increases the area of mass transfer between lithium fluoride liquid and phosphorus pentafluoride gas, increases the reaction rate, and reduces energy consumption.

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a method for preparing lithium hexafluorophosphate from lithium phosphate and hydrogen fluoride, which comprises the following preparation steps: dissolving lithium phosphate in a phosphoric acid aqueous solution to form a mixed solution, and then introducing a mixed gas formed by hydrogen fluoride gas and nitrogen for reaction to obtain lithium hexafluorophosphate. Controlling the feeding molar ratio of the lithium phosphate to the phosphoric acid to the hydrogen fluoride gas to be (1.5-3): 2: (18-20), and after the reaction is completed, decompressing, degassing and concentrating to obtain a mixed crude product of lithium hexafluorophosphate and lithium phosphate; and dissolving the obtained mixed crude product in acetone, carrying out solid-liquid separation, and drying and crystallizing the obtained liquid phase to obtain the high-purity lithium hexafluorophosphate product. According to the method disclosed by the invention, the phosphoric acid aqueous solution is used as a reaction solvent system, meanwhile, the hydrogen fluoride gas is continuously introduced for reaction, and excessive lithium phosphate is adopted for reaction, so that corrosion to reaction equipment can be reduced, side reactions can be reduced, the production safety is improved, and the product yield and quality are improved.

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a method for synthesizing lithium hexafluorophosphate from lithium tripolyphosphate. The synthesis method comprises the following steps: uniformly mixing lithium tripolyphosphate and phosphorus pentoxide in an ether solvent to obtain a first mixture; introducing a mixed gas of hydrogen fluoride and nitrogen into the first mixture, and carrying out a mixed reaction to obtain a second mixture; and carrying out solid-liquid separation on the second mixture, and carrying out reduced-pressure concentration, recrystallization and reduced-pressure drying on the filtrate after solid-liquid separation to obtain lithium hexafluorophosphate. The lithium tripolyphosphate, the phosphorus pentoxide and the hydrogen fluoride are used as raw materials, the hydrogen fluoride gas is uniformly introduced for reaction, the lithium hexafluorophosphate is directly synthesized in the ether solvent, and the method has the advantages of mild reaction conditions, high reaction efficiency, high product purity and high yield. The problems of more byproducts, high cost and the like in the industrial production process of lithium hexafluorophosphate are solved.

A method for producing phosphorus trifluoride and a method for producing phosphorus pentafluoride, which have high reaction efficiency, low reaction temperature and an excellent energy efficiency. The method includes: a step of introducing phosphorus trichloride and hydrogen fluoride into a first reactor, and a step of discharging phosphorus trifluoride from the first reactor, the first reactor contains carbon material. The method includes a step of introducing the phosphorus trifluoride obtained above and chlorine into a second reactor, and a step of discharging dichloro-phosphorus trifluoride from the second reactor. The method further includes a step of introducing the dichloro-phosphorus trifluoride obtained above and hydrogen fluoride into a third reactor; and a step of discharging phosphorus pentafluoride from the third reactor. The method further includes a step of introducing the phosphorus pentafluoride obtained above and lithium fluoride into a fourth reactor; and a step of discharging lithium hexafluorophosphate from the fourth reactor.

The invention relates to a continuous crystallization system and method of lithium hexafluorophosphate, and belongs to the technical field of lithium ion battery electrolyte production. Aiming at the characteristics and requirements of a lithium hexafluorophosphate cooling crystallization process, the invention provides a continuous crystallization system of lithium hexafluorophosphate, which separates cooling nucleation from cooling crystallization. An ultrasonic generating device is introduced into the cooling nucleation module, lithium hexafluorophosphate is stimulated and induced by ultrasonic waves to nucleate, limitation of a metastable region is reduced, the nucleation rate is increased, crystal nuclei are controlled to be within a small particle size distribution range, meanwhile, introduction of impurities in the nucleation process is reduced, and the product purity is guaranteed. And the lithium hexafluorophosphate solution to be crystallized can continuously and uninterruptedly enter the cooling nucleation module, the cooling crystallization module and the separation circulation module in sequence, so that the continuous crystallization of the lithium hexafluorophosphate is realized, the crystallization time is greatly shortened, and the crystallization efficiency is improved.

A degassing device and method for liquid lithium hexafluorophosphate, the degassing device comprising: a scraper evaporator (E201), a post-degassing concentration and collection tank (V301), a condenser (E202), a solvent collection tank (V303) and a vacuum pump (P103), wherein the scraper evaporator (E201) is connected to a conveying line for raw liquid lithium hexafluorophosphate. The raw liquid lithium hexafluorophosphate is heated by the scraper evaporator (E201) and undergoes a rotational centrifugal force of same; thus, part of the liquid is vaporized, and the vaporized material is conveyed into the condenser (E202). The unvaporized liquid is conveyed to the post-degassing concentration and collection tank (V301). An output end of the condenser (E202) is connected to the solvent collection tank (V303), and a gas-phase output end of the solvent collection tank (V303) is connected to the vacuum pump (P103). Thus, an efficient and excellent degassing effect is achieved, it is ultimately ensured that the content of hydrogen chloride in liquid lithium hexafluorophosphate after a degassing treatment is less than 10 ppm, and the performance of the liquid lithium hexafluorophosphate when used as a component of an electrolyte in lithium ion batteries is also ensured.

The present invention provides a preparation method for co-producing lithium difluorophosphate and lithium hexafluorophosphate, which comprises the following steps: 1) Dissolve lithium phosphate in a carbonate solvent to obtain a lithium phosphate solution, and adjust the temperature of the solution to 5-10 °C; 2) Introduce phosphorus pentafluoride gas into the aforementioned lithium phosphate solution and gradually carry out a reaction to generate lithium difluorophosphate and lithium fluoride. The lithium fluoride continues to react with phosphorus pentafluoride to generate lithium hexafluorophosphate. Finally, the molar ratio of lithium phosphate to phosphorus pentafluoride is 1:2 ± 0.1, and a solution of lithium difluorophosphate and lithium hexafluorophosphate is obtained. Among them, lithium hexafluorophosphate dissolves in the carbonate solution to form a lithium hexafluorophosphate solution, and lithium difluorophosphate is slightly soluble in the carbonate and precipitates in the form of crystals to form a turbid solution; 3) Separate the lithium hexafluorophosphate solution and the lithium difluorophosphate turbid solution. The crystalline lithium difluorophosphate is dried to obtain the finished product, and the concentration of the liquid-phase lithium hexafluorophosphate can be directly adjusted and then enter the electrolyte system.

This invention relates to the field of lithium battery technology and discloses a method for purifying lithium hexafluorophosphate by continuous flow crystallization. The method includes: (1) adding a first organic solvent to crude lithium hexafluorophosphate to dissolve it, preparing a saturated lithium hexafluorophosphate-organic solvent solution, filtering to remove insoluble matter, and obtaining a saturated lithium hexafluorophosphate solution; (2) feeding the saturated lithium hexafluorophosphate solution and the second organic solvent into a microchannel reactor for cooling using metering pumps, filtering the precipitated crystals, washing them with a cooled third organic solvent, and then vacuum drying. The lithium hexafluorophosphate precipitated by the method of this invention has high purity and stable quality, making it very suitable for industrial promotion and application.

The application provides a purification method of lithium fluoride, high-purity lithium fluoride, lithium hexafluorophosphate, an electrolyte and a device, and the purification method of the lithium fluoride comprises the following steps: performing water washing treatment on the lithium fluoride to be purified at 0-50 DEG C to obtain a mixture containing a first solid-phase product; performing ultrasonic treatment on the mixture at 20-25 kHz to obtain a second solid-phase product through filtration; performing fluorination reaction on the second solid-phase product with electronic-grade anhydrous hydrofluoric acid to obtain a third liquid-phase product; performing ion exchange on the third liquid-phase product by using a chelating resin at 0-80 DEG C, and then performing cooling evaporation crystallization, and obtaining a fourth solid-phase product through filtration; and performing cleaning treatment on the fourth solid-phase product by using inert gas at 150-250 DEG C to obtain high-purity lithium fluoride. The high-purity lithium fluoride obtained by the purification method has low content of lithium carbonate and other impurities, and is beneficial to improving the performance and stability of subsequent products.

In the crystallization system of the lithium hexafluorophosphate of the present invention, a first-stage crystallization kettle is connected to a lithium hexafluorophosphate mother liquor supply source through a lithium hexafluorophosphate mother liquor supply line; further connected to the lithium hexafluorophosphate mother liquor supply source through a mother liquor heat exchange line connected with a mother liquor heat exchanger; and further connected to a second-stage crystallization kettle through a first mother liquor delivery line configured to deliver lithium hexafluorophosphate mother liquor, a second-stage crystallization kettle is connected to a third-stage crystallization kettle through a second mother liquor delivery line configured to deliver lithium hexafluorophosphate mother liquor, a third-stage crystallization kettle is connected to a fourth-stage crystallization kettle through a crystalline particle delivery line configured to deliver small crystalline particles in the third-stage crystallization kettle; and further connected to a next process device through a first discharging line, and a fourth-stage crystallization kettle is connected to a next process device through a second discharging line. The crystallization system of lithium hexafluorophosphate of the present invention enables different crystallization stages to be carried out separately in different crystallization kettles, so as to realize continuous feeding and continuous discharging in the course of crystallization.

A method of producing lithium difluorophosphate, the method including: a step of obtaining a first raw material mixture by mixing lithium hexafluorophosphate, at least one selected from the group consisting of an oxide of phosphorus (A) and a lithium salt of a phosphoric acid (B), and a hydrocarbon solvent having from 6 to 12 carbon atoms; a step of obtaining a second raw material mixture by removing at least a part of the hydrocarbon solvent contained in the obtained first raw material mixture; and a step of producing a crude product containing lithium difluorophosphate by reacting the second raw material mixture.

A method for generating / synthesising a metal hexafluorophosphate is disclosed which comprises dissolving ammonium hexafluorophosphate in tetrahydrofuran (THF) solvent, and flowing the resulting dissol

This application discloses hexafluorophosphate, phosphorus pentafluoride, and its preparation method and use. This application does not use phosphorus pentafluoride as raw material to prepare hexafluorophosphate, and does not use hydrogen fluoride as raw material to produce phosphorus pentafluoride, reducing the safety risk of production, and uses chemical reagents such as diphosphorus pentaoxide and sulfur trioxide, which have a wide supply source, as raw materials, reducing raw material costs and favoring industrial large-scale production. [Means] The method for preparing the hexafluorophosphate comprises mixing a phosphoric acid solution of diphosphorus pentoxide with sulfur trioxide and a fluoride in an inert gas atmosphere, and after the reaction, sequentially carrying out evaporation concentration, dissolution, filtration and drying to obtain the hexafluorophosphate. The method for preparing the phosphorus pentafluoride using the hexafluorophosphate obtained by the preparation method of the present application comprises mixing the hexafluorophosphate with a catalyst solution, and after the catalytic reaction, sequentially carrying out condensation, pressurization liquefaction and removal of impurities by adsorption to obtain the phosphorus pentafluoride.

The invention relates to a safe and environment-friendly treatment method for residues in a tail gas pipeline of a lithium hexafluorophosphate drying process, which comprises the following steps: connecting a tail gas buffer tank in series in the tail gas pipeline of the lithium hexafluorophosphate drying process, and collecting waste materials formed by sedimentation from the tail gas buffer tank; the waste material is treated by the following steps: 1) adding ultrapure water and the lithium hexafluorophosphate waste material into a hydrolysis kettle, hydrolyzing, and extracting hydrofluoric acid through negative pressure azeotropy; 2) centrifuging; centrifugally collecting filtrate as phosphoric acid, and washing a filter cake until effluent is neutral to form crude lithium fluoride; 3) adding ultrapure water and concentrated hydrochloric acid into the crude lithium fluoride; after stirring for 0.5-1 hour, centrifuging to remove iron ions, washing a filter cake with ultrapure water until effluent is neutral, and discharging the filter cake to obtain wet lithium fluoride; and 4) drying the wet lithium fluoride until the moisture is qualified to obtain the lithium fluoride for lithium hexafluorophosphate production.According to the method, the pipeline maintenance cost is reduced, meanwhile, the lithium fluoride and byproducts of hydrofluoric acid and phosphoric acid are recovered from the waste material formed by collection, and the method is environment-friendly and energy-saving.

Provided herein are compositions and methods of making compositions useful in the production of battery electrolyte precursors and battery electrolytes.

The invention belongs to the technical field of electrolyte material preparation, and particularly relates to a method for continuously preparing lithium hexafluorophosphate. The preparation method comprises the following steps: pulping and uniformly mixing excessive liquid PF5 and solid LiF in a pulping kettle, introducing the mixed material into a continuous reactor, controlling the temperature in the reactor to be greater than 18.95 DEG C and the pressure in the reactor to be greater than 3.39 MPa so that the PF5 is in a supercritical state, carrying out stirring reaction, decompressing the reaction material, feeding the reaction material into a spray drying tower, and carrying out solid-gas separation, the solid-phase product is lithium hexafluorophosphate, and the gas-phase component is PF5 which is compressed, condensed and recycled as a reaction raw material. According to the preparation method, the supercritical PF5 serves as a reaction raw material and a heat and mass transfer carrier at the same time, the reaction efficiency can be remarkably improved, other solvents or gas phase components are not introduced, and therefore efficient and high-quality continuous preparation of lithium hexafluorophosphate is achieved.

The invention relates to a preparation process of high-purity lithium hexafluorophosphate, which comprises the following specific steps: S1, quantitatively adding anhydrous hydrogen fluoride into a corresponding reaction kettle body, and controlling the environment temperature in the reaction kettle body at-50 DEG C to-20 DEG C through a temperature control device; s2, maintaining the pressure in the reaction kettle body at 0.1-0.5 MPa, dispersing and adding solid phosphorus pentachloride into the reaction kettle body through a corresponding feeding device, and enabling the solid phosphorus pentachloride to react with the anhydrous hydrogen fluoride in the step S1 at the temperature of-50 DEG C to-20 DEG C to obtain phosphorus pentafluoride and gaseous hydrogen chloride, the gaseous hydrogen chloride escapes from the reaction liquid and then is discharged for recovery or absorption treatment; and S3, dispersing and adding lithium fluoride into the reaction kettle body through the feeding device, and carrying out complexing reaction on the lithium fluoride and phosphorus pentafluoride in the anhydrous hydrogen fluoride to obtain lithium hexafluorophosphate. The reaction process is high in controllability, so that the high-purity lithium hexafluorophosphate product can be stably prepared.

The invention relates to the technical field of lithium ion batteries, and discloses a method for preparing high-purity lithium hexafluorophosphate: 1) reacting phosphorus pentachloride with anhydrous hydrofluoric acid or hydrogen fluoride gas to prepare phosphorus pentafluoride; 2) dissolving LiF in an anhydrous HF solvent, and then introducing the obtained phosphorus pentafluoride therein to react and obtain an anhydrous HF solution of lithium hexafluorophosphate; 3) distilling the obtained anhydrous HF solution of lithium hexafluorophosphate to remove hydrofluoric acid, and obtain solid lithium hexafluorophosphate; 4) using supercritical carbon dioxide or liquid carbon dioxide as a solvent, recrystallizing the lithium hexafluorophosphate solid to obtain purified lithium hexafluorophosphate. The present invention uses carbon dioxide for recrystallization, which is green and environmentally friendly, low in cost, safe in the production process, and good in purification effect; the present invention collects and separates the reaction gas in step 2) and then reuses it to form a full-process clean production process of lithium hexafluorophosphate, and the entire production process is green and environmentally friendly, with less waste discharge.

The application discloses a preparation method of a flame-retardant lithium hexafluorophosphate organic solution, lithium hexafluorophosphate and a lithium battery. The preparation method comprises the following steps: mixing and reacting a lithium hexafluorophosphate salt and a benign flame-retardant solvent solution containing a lithium compound to obtain a lithium hexafluorophosphate solution with a flame-retardant effect, wherein the benign flame-retardant solvent comprises at least one of a phosphate ester and a phosphite ester; removing part of the solvent in the lithium hexafluorophosphate solution with the flame-retardant effect to obtain a concentrated solution; adding a carbonate to the concentrated solution to remove impurities; and then removing the carbonate to obtain the flame-retardant lithium hexafluorophosphate organic solution. The preparation method of the flame-retardant lithium hexafluorophosphate organic solution provided by the application does not require a strict anhydrous and anaerobic reaction environment, and the reaction speed is fast. The obtained flame-retardant lithium hexafluorophosphate organic solution does not need to go through processes such as drying, crystallization and dissolution, and can be directly used in a battery and has a certain flame-retardant property. The performance of the flame-retardant lithium hexafluorophosphate organic solution is similar to that of a commercial electrolyte.

Disclosed are a process and continuous system for producing LiPF6, and a prepared mixture crystal, composition, electrolyte solution and lithium ion battery containing LiPF6. During preparation, a first feed stream containing PF5 and a second feed stream containing LiF and HF are introduced into a first microchannel reactor, a gas part of a product in the first microchannel reactor is introduced into a second microchannel reactor to react with a third feed stream containing LiPF6, LiF and HF, and a liquid part of the product in the first microchannel reactor is subjected to crystallization and drying to obtain LiPF6. The LiPF6 has the advantages of a high purity, a uniform particle size, a high product quality stability, etc., and is suitable for use as a component of an electrolyte solution of a lithium ion battery.

In the crystallization system of the lithium hexafluorophosphate of the present invention, a first-stage crystallization kettle is connected to a lithium hexafluorophosphate mother liquor supply source through a lithium hexafluorophosphate mother liquor supply line; further connected to the lithium hexafluorophosphate mother liquor supply source through a mother liquor heat exchange line connected with a mother liquor heat exchanger; and further connected to a second-stage crystallization kettle through a first mother liquor delivery line configured to deliver lithium hexafluorophosphate mother liquor, a second-stage crystallization kettle is connected to a third-stage crystallization kettle through a second mother liquor delivery line configured to deliver lithium hexafluorophosphate mother liquor, a third-stage crystallization kettle is connected to a fourth-stage crystallization kettle through a crystalline particle delivery line configured to deliver small crystalline particles in the third-stage crystallization kettle; and further connected to a next process device through a first discharging line, and a fourth-stage crystallization kettle is connected to a next process device through a second discharging line. The crystallization system of lithium hexafluorophosphate of the present invention enables different crystallization stages to be carried out separately in different crystallization kettles, so as to realize continuous feeding and continuous discharging in the course of crystallization.

The present invention discloses a method for synthesizing hexafluorophosphate, which belongs to the technical field of chemical synthesis. A phosphorus pentahalide inert solvent solution in which phosphorus pentahalide is dissolved in an inert solvent and an alkali metal halide salt-hydrogen fluoride solution in which an alkali metal halide salt is dissolved in anhydrous hydrogen fluoride are charged into a reactor at a predetermined ratio to react with each other, and a mixture of hexafluorophosphate salt, hydrogen fluoride, an inert solvent and hydrogen halide salt is obtained. Then, hydrogen halide gas is removed by gas-liquid separation, hydrogen fluoride is recovered by heating evaporation, and finally, the inert solvent is recovered by solid-liquid separation, and the solid is dried to obtain hexafluorophosphate salt. The synthesis method of the present invention has the advantages of simple operation, excellent safety, high reaction yield, excellent product quality, and continuous production.

The present invention relates to processes for the preparation of phosphorus pentafluoride and lithium hexafluorophosphate.

This invention discloses a method for preparing phosphorus pentafluoride and co-producing difluorochloromethane. The method includes the following steps: 1) vaporizing PCl and reacting it with CHF3 and Cl2 in a reaction tube equipped with a supported catalyst to undergo a fluorine-chlorine exchange reaction, yielding a mixed gas containing products such as PF5 and CHClF2; 2) fractionating the mixed gas in a distillation column, collecting the product PF5 and unreacted CHF3 mixture from the top of the condenser. This mixture is then directly reacted with a LiF carbonate solution to convert it into a high-value-added lithium hexafluorophosphate solution; another product, CHClF2, is collected from the body of the distillation column. This invention utilizes CHF3, a high-temperature-effect, long-life fluorine chemical byproduct, as a fluorine source and PCl3 as a phosphorus source. Through the fluorine-chlorine exchange reaction of CF3H, PCl3, and Cl2, it converts into high-value-added PF5 gas, which is further converted into LiPF6, while simultaneously co-producing CHClF2, thus realizing the resource utilization of fluorine and possessing significant economic and social benefits.

The invention relates to reaction equipment for preparing lithium hexafluorophosphate, which comprises a reaction kettle body, and a stirring shaft is rotatably mounted in the reaction kettle body; the feeding assembly comprises a set of discharging hoppers, and fixing plug bodies are installed on the bottom sides of the discharging hoppers in a liftable mode; the dispersing and discharging assembly comprises a set of arc-shaped guide grooves formed in the lower side of the fixed plug body, and the middles of the arc-shaped guide grooves protrude upwards; when the arc-shaped material guide groove rotates to pass through the bottom side of the fixed plug body, the driving mechanism drives the fixed plug body to leave the discharging opening of the discharging hopper; the heat exchange jacket is fixedly mounted on the outer side of the reaction kettle body, corresponding fixing grooves are concavely formed in the bottom side of the reaction kettle body at intervals, and corresponding heat exchange containers are respectively mounted in the fixing grooves in a swinging manner. According to the invention, the blanking uniformity of the material can be effectively and greatly improved, and the uniformity of the reaction temperature of the material in different reaction area ranges can be effectively and obviously improved.

The application discloses a continuous preparation process and device of liquid lithium hexafluorophosphate, and comprises the following operation steps: A10), continuously feeding lithium fluoride suspension to the top of a hexafluoride reaction plate tower; continuously feeding gaseous high-purity phosphorus pentafluoride to the bottom of the hexafluoride reaction plate tower; A20), carrying out reaction in the hexafluoride reaction plate tower, and feeding the reaction product from the bottom of the hexafluoride reaction tower into a bottom tank; A30), feeding the remaining reaction product output by a circulating heat exchanger into a liquid lithium hexafluorophosphate product extraction tank in one way and into a lithium fluoride suspension preparation kettle in the other way; and A40), connecting a filter to the product extraction end of the product extraction tank to remove the excessive solid-phase material after reaction, so as to obtain the liquid lithium hexafluorophosphate, the hydrogen chloride content of which is less than 25 ppm, and the hydrogen fluoride is not detected; the application has high continuous level and stability, does not need additional deacidification treatment, and has obviously higher output efficiency, and does not have the hidden troubles of shutdown maintenance due to problems such as blockage.

The invention relates to a preparation method of lithium hexafluorophosphate, and belongs to the field of preparation of lithium hexafluorophosphate. The preparation method comprises the following steps: carrying out a high-pressure dry reaction on a lithium fluoride solid and phosphorus pentafluoride gas, continuously introducing the phosphorus pentafluoride gas, pressurizing to 3.4 MPa or above, maintaining the pressure, cooling, and reducing the pressure to prepare lithium hexafluorophosphate; the pressure of the high pressure is 0.9 to 2.5 MPa, and the particle size of the lithium fluoride solid is 200 to 600 meshes. According to the method, the pressure of a reaction system is increased to 3.4 MPa or above, and the pressure is maintained, so that phosphorus pentafluoride gas reaches a gas-liquid supercritical state, and fine lithium hexafluorophosphate crystal particles are rearranged and grow in crystal structures in the environment and are approximately dissolved in the gas-liquid supercritical state of phosphorus pentafluoride; in this way, phosphorus pentafluoride can permeate into crystal grains to further react with lithium fluoride, the residue of lithium fluoride impurities is reduced, and therefore the purity of lithium hexafluorophosphate is improved.

Disclosed are a manufacturing apparatus and manufacturing method for lithium hexafluorophosphate. The disclosed manufacturing apparatus for lithium hexafluorophosphate is configured to synthesize lithium hexafluorophosphate by reacting phosphorus pentafluoride with lithium fluoride and liquid anhydrous hydrogen fluoride, and comprises: a plurality of reactors connected to each other in series; and a plurality of recrystallizers connected to each other in series and installed downstream of the plurality of reactors so as to recrystallize the lithium hexafluorophosphate synthesized in the presence of phosphorus pentafluoride.

The crystallizer comprises a vertical container, the vertical container is installed on a fixing support through an elastic mechanism, and a vibration unit is further installed on the vertical container; a jacket matched with the vertical container in shape is arranged outside the vertical container, a refrigerant cavity is formed between the jacket and the vertical container, and the jacket is further provided with a refrigerant inlet and a refrigerant outlet which are communicated with the refrigerant cavity; the vertical container is provided with a mother liquor feed port, a nitrogen inlet, a mother liquor outlet and a discharge port; the discharge port is positioned at the bottom of the vertical container and is used for discharging crystallized materials, and meanwhile, a discharge valve for controlling the discharge port to be opened and closed is also arranged at the discharge port; the nitrogen inlet and the mother liquor outlet are positioned at the top of the vertical container, and a mother liquor insertion pipe downwards extending into the vertical container is also arranged at the mother liquor outlet. The device is simple in structure, easy to operate and capable of prohibiting external air from making contact with materials, controlling the amount of insoluble substances of lithium hexafluorophosphate and ensuring the stability of the quality of lithium hexafluorophosphate.

The application relates to a preparation method of a hexafluorophosphate, and belongs to the field of battery electrolytes. The preparation method comprises the following steps: carrying out an electrolysis reaction on anhydrous HF, phosphorus powder and an alkali metal fluoride salt to generate the hexafluorophosphate. The weak fluorine is electrolyzed from the anhydrous HF, and then the weak fluorine, the phosphorus powder and the alkali metal fluoride salt are reacted to directly synthesize the hexafluorophosphate by one-pot method, so that the yield is higher and the operation is simple. Compared with the reaction of fluorine gas and elemental phosphorus, the reaction of the weak fluorine obtained by the electrolysis method and the phosphorus powder is more moderate, easy to control and high in safety.