A device and method for synthesizing liquid lithium hexafluorophosphate

Abstract

The application discloses a kind of synthesis device and method of liquid lithium hexafluorophosphate, belong to the technical field of electrolyte, the synthesis device of liquid lithium hexafluorophosphate provided by the present application includes hexafluorophosphate synthesis kettle, filter drying kettle, decomposition device, compressor, condenser, phosphorus pentafluoride gas buffer tank, rectifying tower and target product synthesis kettle.The application significantly improves the yield of hexafluorophosphate (sodium, lithium, potassium, calcium, magnesium) powder through hexafluorophosphate synthesis kettle, the application improves the purity of phosphorus pentafluoride gas through decomposition device, compressor, condenser, rectifying tower, the application improves the efficiency and product quality of producing liquid lithium hexafluorophosphate through target product synthesis kettle.

Description

Technical Field

[0001] This invention relates to the field of electrolyte technology, and in particular to an apparatus and method for synthesizing liquid lithium hexafluorophosphate. Background Technology

[0002] Lithium hexafluorophosphate (LiPF6) is currently the core solute in lithium-ion battery electrolytes. With its excellent ionic conductivity, good electrochemical stability and compatibility with various positive and negative electrode materials of lithium-ion batteries, it is recognized as the preferred electrolyte material in lithium-ion batteries (especially power lithium batteries and energy storage lithium batteries). Its purity and performance directly determine the energy density, cycle life and safety performance of lithium-ion batteries.

[0003] Currently, several published patents indicate that using phosphorus, fluorine, and lithium sources as raw materials, and fuming sulfuric acid as a dehydrating agent, a multi-step chemical reaction, including the high-temperature decomposition of phosphorus pentafluoride gas by hexafluorophosphate, gradually transforms the phosphorus into liquid lithium hexafluorophosphate, which can be directly used as an electrolyte in lithium-ion batteries, into a final product in an organic solvent system. During the generation of hexafluorophosphate from phosphorus and fluorine sources, a large amount of water is generated. Using a large amount of fuming sulfuric acid to remove this water effectively prevents the water from reacting with the phosphorus pentafluoride gas generated during the high-temperature decomposition of hexafluorophosphate to form phosphorus oxyfluoride gas and hydrogen fluoride gas. Therefore, the effectiveness of fuming sulfuric acid in removing water directly affects the yield and purity of phosphorus pentafluoride gas, and consequently, the quality of the reaction system and the final product. Simultaneously, the water generated during the generation of hexafluorophosphate from phosphorus and fluorine sources forms hydrofluoric acid, requiring extremely high corrosion resistance in the production equipment, thus increasing equipment investment costs.

[0004] A relevant patent document discloses a method for preparing liquid lithium hexafluorophosphate. The method involves reacting a mixture of phosphorus and fluorine sources to prepare an aqueous solution of hexafluorophosphate. A sodium source is then added to the aqueous solution of hexafluorophosphate for neutralization, yielding sodium hexafluorophosphate. The sodium hexafluorophosphate solid is then decomposed by heating to produce phosphorus pentafluoride gas, which is finally reacted in an organic solvent to obtain liquid lithium hexafluorophosphate. This method does not use fuming sulfuric acid, has low equipment requirements, and offers good reaction safety. However, in the synthesis of sodium hexafluorophosphate powder and the thermal decomposition of lithium pentafluoride gas, the yield of sodium hexafluorophosphate is low due to the complex reactions and processes involved. Even under optimal vacuum drying conditions when water is used as a solvent, the moisture content of sodium hexafluorophosphate powder is still 20-50 ppm. The decomposition of sodium hexafluorophosphate powder produces phosphorus pentafluoride gas, which reacts with water to generate phosphorus oxyfluoride gas and hydrogen fluoride gas, affecting the quality of the product. In the synthesis of liquid lithium hexafluorophosphate, this process cannot achieve efficient utilization and full reaction of phosphorus pentafluoride gas, resulting in low reaction efficiency. Prolonged introduction of phosphorus pentafluoride gas not only introduces more hydrogen fluoride but also causes the decomposition of carbonate solvents, thereby increasing the color and small organic molecule impurities in the product, ultimately reducing the purity of the liquid lithium hexafluorophosphate product. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for synthesizing liquid lithium hexafluorophosphate. The apparatus and method provided by this invention significantly improve the production yield and purity of liquid lithium hexafluorophosphate, while effectively reducing the hydrogen fluoride content in the liquid lithium hexafluorophosphate, resulting in a product with lower acid value and color. Furthermore, no water is generated during the entire synthesis process, and hydrofluoric acid is not formed, thus requiring less sophisticated production equipment.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a synthesis apparatus for liquid lithium hexafluorophosphate, comprising a hexafluorophosphate synthesis vessel, several filtration and drying vessels, a decomposition device, a compressor, a condenser, a phosphorus pentafluoride gas buffer tank, a distillation column, and a target product synthesis vessel; At least two hexafluorophosphate synthesis reactors are provided. The upper end of each hexafluorophosphate synthesis reactor is provided with an anhydrous hydrogen fluoride inlet, a phosphorus source-metal source mixture inlet, a gas phase inlet, a gas phase outlet, and a hydrogen chloride exhaust port. The lower end is provided with a discharge port. The reactor is equipped with a stirring component and a cooling mechanism. The gas phase inlet and gas phase outlet of each hexafluorophosphate synthesis reactor are connected by a pipeline. The filtration and drying kettle is provided with a liquid phase inlet, a nitrogen inlet, and a gas phase outlet at the upper end, and a filtrate discharge port and a hexafluorophosphate powder discharge port at the lower end. It is equipped with a stirring component inside and a filter screen on the bottom inner wall. The filtration and drying kettle is equipped with a heating mechanism. The lower discharge port of the hexafluorophosphate synthesis kettle is connected to the upper liquid phase inlet of the filtration and drying kettle. The decomposition device is provided with a hexafluorophosphate powder inlet at one end, which is connected to the hexafluorophosphate powder outlet of the filter drying kettle, and a phosphorus pentafluoride gas outlet and a metal fluoride powder outlet at the other end. The decomposition device is equipped with a heating mechanism and is a furnace, kettle, or kiln. The phosphorus pentafluoride gas outlet of the decomposition device is sequentially connected to the compressor, the condenser, the phosphorus pentafluoride gas buffer tank, and the distillation column; The target product synthesis reactor is equipped with a phosphorus pentafluoride gas inlet and a lithium fluoride inlet at the upper end and a discharge port at the lower end. It contains a stirring component. The phosphorus pentafluoride gas inlet is connected to the outlet of the distillation column. The target product synthesis reactor is equipped with a cooling mechanism. A coil is located at the upper end of the reactor's interior, with multiple spray nozzles mounted on it. A porous coil is also located inside the reactor, connected to the phosphorus pentafluoride gas inlet via a pipe. Multiple evenly arranged exhaust holes are located on the wall of the porous coil. A deacidification column is located on the outside of the reactor. The inlet of the deacidification column is connected to the discharge port of the reactor, and the discharge port is connected to the coil. A bottom-circulation pump is installed on the pipe connecting the inlet of the deacidification column and the discharge port of the reactor.

[0007] Preferably, the device further includes a metal source storage tank, a phosphorus source storage tank, and a screw feeder. The bottom outlets of the metal source storage tank and the phosphorus source storage tank are both connected to the inlet of the screw feeder. The outlet of the screw feeder is connected to the phosphorus source-metal source mixture inlet of each of the hexafluorophosphate synthesis reactors. Metering devices are provided on the pipelines between the bottom outlets of the metal source storage tank and the phosphorus source storage tank and the inlet of the screw feeder.

[0008] Preferably, each of the hexafluorophosphate synthesis reactors is provided with a gas phase inlet bottom pipe connected to the gas phase inlet, the gas phase inlet bottom pipe extending to the inner bottom of the hexafluorophosphate synthesis reactor, and the gas phase inlet bottom pipe is provided with multiple gas outlet holes.

[0009] Preferably, each of the hexafluorophosphate synthesis reactors is provided with a mixture feed inlet pipe connected to the phosphorus source-metal source mixture inlet. The mixture feed inlet pipe extends into the bottom of the hexafluorophosphate synthesis reactor and has multiple discharge holes.

[0010] Preferably, the filtration and drying vessel is connected to the decomposition device via a volume or mass metering feeder; the fluoride powder outlet of the decomposition device is connected to the inlet of the metal fluoride powder receiving tank.

[0011] Preferably, the diameter of the exhaust port is 0.2~3mm.

[0012] Preferably, it also includes a concentration device, and the outlet of the target product synthesis vessel is connected to the concentration device.

[0013] This invention provides a method for synthesizing liquid lithium hexafluorophosphate, using the apparatus described above for synthesizing liquid lithium hexafluorophosphate, and includes the following steps: Anhydrous hydrogen fluoride and a phosphorus source-metal source mixture are passed into the hexafluorophosphate synthesis reactor to react and obtain a hexafluorophosphate solid-liquid mixture and hydrogen chloride gas. The phosphorus source-metal source mixture is obtained by mixing a phosphorus source and a metal source. The solid-liquid mixture of hexafluorophosphate is fed into the filtration and drying kettle for solid-liquid separation and heating and drying to obtain hexafluorophosphate powder. The hexafluorophosphate powder is intermittently or continuously fed into the decomposition device for heating and decomposition to obtain phosphorus pentafluoride gas and metal fluoride powder. The phosphorus pentafluoride gas is compressed by a compressor and cooled by a condenser in sequence, and then enters a phosphorus pentafluoride gas buffer tank. It is then sent to a distillation column for purification to obtain purified phosphorus pentafluoride gas. Organic solvent and lithium fluoride are added to the target product synthesis vessel. Refined phosphorus pentafluoride gas is introduced into the target product synthesis vessel through the phosphorus pentafluoride gas inlet. After being vented through the exhaust port of the porous coil, it comes into contact with lithium fluoride to react. During the reaction, the stirrer and the bottom external circulation pump are turned on. The reaction solution in the target product synthesis vessel is deacidified and circulated through the deacidification column. The liquid returned to the target product synthesis vessel by the deacidification column is sprayed by the spray head. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis vessel. After the reaction is completed, liquid lithium hexafluorophosphate is obtained.

[0014] Preferably, the metal source includes one or more of sodium, lithium, potassium, calcium and magnesium sources; the metal source is a metal fluoride, and the metal source is selected from the metal fluoride produced by the decomposition of hexafluorophosphate powder; the phosphorus source includes phosphorus pentachloride; the molar ratio of the metal source, phosphorus source and anhydrous hydrogen fluoride is 1:1.0~1.2:20~30.

[0015] Preferably, the temperature for the thermal decomposition is 200~600℃; The organic solvent includes one or more of dimethyl carbonate, ethyl methyl carbonate, methyl acetate, and ethyl acetate.

[0016] This invention provides an apparatus and method for synthesizing liquid lithium hexafluorophosphate. Compared with the prior art, this invention achieves the following beneficial effects: the apparatus for synthesizing liquid lithium hexafluorophosphate provided by this invention effectively improves the production efficiency of hexafluorophosphate by using a mixed feed of phosphorus source and metal source. The present invention provides a synthesis apparatus for liquid lithium hexafluorophosphate, comprising a filtration and drying vessel and a decomposition device. The filtration and drying vessel is equipped with a filter screen to first filter the liquid hydrogen fluoride from the hexafluorophosphate in the synthesis vessel. The remaining hexafluorophosphate is dried to obtain hexafluorophosphate powder. The hexafluorophosphate powder is intermittently or continuously fed to the decomposition device for heating and decomposition into phosphorus pentafluoride gas and metal fluoride powder. The metal fluoride powder is further recovered and reused as raw material. This apparatus achieves continuous gas production in the decomposition device of hexafluorophosphate by switching the feed through the filtration and drying vessel. Simultaneously, the hexafluorophosphate powder, after drying in the filtration and drying vessel, is decomposed again, producing only phosphorus pentafluoride gas and metal fluoride powder. Compared with existing technologies, the phosphorus pentafluoride gas produced by the present invention does not contain impurities such as hydrogen fluoride, hydrogen chloride, and phosphorus trifluoride oxyfluoride, resulting in higher purity phosphorus pentafluoride gas. The target product synthesis vessel provided by the present invention is equipped with a porous coil, such as… Figure 3 As shown, refined phosphorus pentafluoride gas is introduced into the solvent through the exhaust port of the porous coil to react with lithium fluoride, increasing reaction efficiency. Simultaneously, the target product synthesis vessel provided by this invention is equipped with a deacidification column on its outer side. Through external circulation of the deacidification column, the liquid inside the target product synthesis vessel is pumped into the top of the vessel and sprayed, allowing the phosphorus pentafluoride gas in the hollow part of the vessel to re-react with the liquid, thus achieving almost complete reaction of the phosphorus pentafluoride gas introduced into the vessel. This invention, through the external circulation of the deacidification column, can further adsorb PPM-level hydrogen fluoride generated in the liquid lithium hexafluorophosphate due to trace amounts of water in the lithium fluoride and solvent, thereby reducing the acid value and improving product purity. Compared with existing technologies, which directly introduce phosphorus pentafluoride gas into the lithium fluoride solvent, the existing technology forms a gas stream that passes through the solution to the upper cavity of the vessel, failing to achieve a complete reaction. This invention utilizes a porous coil to avoid the formation of a gas stream in the solution, improving reaction efficiency. Simultaneously, this invention utilizes external circulation in the deacidification column, through spraying, to ensure that the unreacted phosphorus pentafluoride gas accumulated at the top of the target product synthesis vessel can also react completely. Therefore, the liquid lithium hexafluorophosphate synthesis apparatus provided by this invention significantly improves the yield and purity of liquid lithium hexafluorophosphate production, and effectively reduces the hydrogen fluoride content in liquid lithium hexafluorophosphate (lowering the acid value). Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the hexafluorophosphate synthesis reactor in this invention; Figure 2 This is a schematic diagram of the structure of the filtration and drying kettle and the decomposition device in this invention; Figure 3 This is a schematic diagram of the structure of the target product synthesis reactor in this invention; Figure 4 This is a flowchart illustrating the method for synthesizing liquid lithium hexafluorophosphate provided by the present invention.

[0019] In the diagram: 101-Metal source storage tank, 102-Phosphorus source storage tank, 103-Screw feeder, 104A-First metering device, 104B-Second metering device, 105A-First hexafluorophosphate synthesis reactor, 105B-Second hexafluorophosphate synthesis reactor, 105C-Third hexafluorophosphate synthesis reactor, 106A-Jacket of the first hexafluorophosphate synthesis reactor, 106B-Jacket of the second hexafluorophosphate synthesis reactor, 106C-Jacket of the third hexafluorophosphate synthesis reactor, 107A-Refrigerator inlet of the jacket of the first hexafluorophosphate synthesis reactor, 107B-Refrigerator inlet of the jacket of the second hexafluorophosphate synthesis reactor, 107C-Refrigerator inlet of the jacket of the third hexafluorophosphate synthesis reactor, 108A-Discharge port of the first hexafluorophosphate synthesis reactor, 108B - Second hexafluorophosphate synthesis reactor outlet, 108C - Third hexafluorophosphate synthesis reactor outlet, 109A - First hexafluorophosphate synthesis reactor jacket refrigerant outlet, 109B - Second hexafluorophosphate synthesis reactor jacket refrigerant outlet, 109C - Third hexafluorophosphate synthesis reactor jacket refrigerant outlet, 110A - First hexafluorophosphate synthesis reactor gas phase outlet, 110B - Second hexafluorophosphate synthesis reactor gas phase outlet, 110C - Third hexafluorophosphate synthesis reactor gas phase outlet, 111A - First hexafluorophosphate synthesis reactor gas phase inlet, 111B - Second hexafluorophosphate synthesis reactor gas phase inlet, 111C - Third hexafluorophosphate synthesis reactor gas phase inlet, 112A - First hexafluorophosphate synthesis reactor hydrogen chloride exhaust port, 112B - The following are the ports / ports for the synthesis reactors: 112C - Hydrogen chloride exhaust port of the second hexafluorophosphate synthesis reactor; 113A - Anhydrous hydrogen fluoride inlet of the first hexafluorophosphate synthesis reactor; 113B - Anhydrous hydrogen fluoride inlet of the second hexafluorophosphate synthesis reactor; 113C - Anhydrous hydrogen fluoride inlet of the third hexafluorophosphate synthesis reactor; 114A - Phosphorus source-metal source mixture inlet of the first hexafluorophosphate synthesis reactor; 114B - Phosphorus source-metal source mixture inlet of the second hexafluorophosphate synthesis reactor; 114C - Phosphorus source-metal source mixture inlet of the third hexafluorophosphate synthesis reactor; 115A - Mixture inlet bottom pipe of the first hexafluorophosphate synthesis reactor; 115B - Mixture inlet bottom pipe of the second hexafluorophosphate synthesis reactor; 115C... - Bottom inlet pipe for the mixture in the third hexafluorophosphate synthesis reactor; 116A - Outlet port for the phosphorus source-metal source mixture in the first hexafluorophosphate synthesis reactor; 116B - Outlet port for the phosphorus source-metal source mixture in the second hexafluorophosphate synthesis reactor; 116C - Outlet port for the phosphorus source-metal source mixture in the third hexafluorophosphate synthesis reactor; 117A - Bottom inlet pipe for the gas phase inlet of the first hexafluorophosphate synthesis reactor; 117B - Bottom inlet pipe for the gas phase inlet of the second hexafluorophosphate synthesis reactor; 117C - Bottom inlet pipe for the gas phase inlet of the third hexafluorophosphate synthesis reactor; 118A - Gas outlet of the first hexafluorophosphate synthesis reactor; 118B - Gas outlet of the second hexafluorophosphate synthesis reactor; 118C - Gas outlet of the third hexafluorophosphate synthesis reactor; R-201A - First filtration and drying reactor.R-201B - Second Filtration and Drying Kettle, 202A - First Liquid Phase Inlet, 202B - Second Liquid Phase Inlet, 203A - First Nitrogen Inlet, 203B - Second Nitrogen Inlet, 204A - First Gas Phase Outlet, 204B - Second Gas Phase Outlet, 205A - First Filtrate Discharge Port, 205B - ​​Second Filtrate Discharge Port, 206A - First Hexafluorophosphate Powder Discharge Port, 206B - Second Hexafluorophosphate Powder Discharge Port, 207A - First Stirring Device, 20 7B - Second stirring device, T-208A - First thermometer, T-208B - Second thermometer, P-209A - First pressure gauge, P-209B - Second pressure gauge, L-210A - First level gauge, L-210B - Second level gauge, E-211A - First heating mechanism, E-211B - Second heating mechanism, 212A - First filter screen, 212B - Second filter screen, E-213 - Decomposition device, T-214 - Decomposition device thermometer, P- 215 - Pressure gauge for decomposition unit; 216 - Phosphorus pentafluoride gas outlet; 217 - Fluoride powder outlet; V-218A - First fluoride powder receiving tank; V-218B - Second fluoride powder receiving tank; P-219A - Pressure gauge for first fluoride powder receiving tank; P-219B - Pressure gauge for second fluoride powder receiving tank; W-220A - First weighing module; W-220B - Second weighing module; 221 - Fluoride powder outlet; 301 - Target product 302-Bottom external circulation pump for the target product synthesis reactor; 303-Deacidification column; 304-Spray head; 305-Nitrogen inlet; 306-Circulation inlet; 307-Lithium fluoride inlet; 308-Phosphorus pentafluoride gas inlet; 309-Target product synthesis reactor jacket; 310-Lithium hexafluorophosphate outlet; 311-Deacidification resin; 312-Porous coil; 313-Exhaust vent; 314-Target product synthesis reactor jacket refrigerant inlet; 315-Target product synthesis reactor jacket refrigerant outlet. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a hexafluorophosphate synthesis apparatus to solve the problems existing in the prior art, significantly improve the yield and purity of liquid lithium hexafluorophosphate, and effectively reduce the hydrogen fluoride content in liquid lithium hexafluorophosphate.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a liquid lithium hexafluorophosphate synthesis apparatus, including a hexafluorophosphate synthesis kettle, several filtration and drying kettles, a decomposition device, a compressor, a condenser, a phosphorus pentafluoride gas buffer tank, a distillation column, and a target product synthesis kettle.

[0024] The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention includes a hexafluorophosphate synthesis vessel. At least two hexafluorophosphate synthesis vessels are provided. The upper end of each vessel is equipped with an anhydrous hydrogen fluoride inlet, a phosphorus source-metal source mixture inlet, a gas phase inlet, a gas phase outlet, and a hydrogen chloride exhaust outlet, and is also equipped with a thermometer, pressure gauge, and level gauge. The lower end is equipped with a liquid lithium hexafluorophosphate outlet. An internal stirring component is provided, and the hexafluorophosphate synthesis vessel is equipped with a cooling mechanism. The gas phase inlet and gas phase outlet of each hexafluorophosphate synthesis vessel are connected by a pipeline. In this invention, the cooling mechanism includes a hexafluorophosphate synthesis vessel jacket disposed on the outer wall of the hexafluorophosphate synthesis vessel. The bottom of the jacket has a hexafluorophosphate synthesis vessel jacket refrigerant inlet, and the upper part has a hexafluorophosphate synthesis vessel jacket refrigerant outlet.

[0025] In this invention, the hexafluorophosphate synthesis reactor comprises three reactors arranged in parallel.

[0026] In a specific embodiment of the present invention, the hexafluorophosphate synthesis reactor includes a first hexafluorophosphate synthesis reactor 105A, a second hexafluorophosphate synthesis reactor 105B, and a third hexafluorophosphate synthesis reactor 105C connected in parallel with phosphorus source-metal source mixture inlets. In the production process, any one of the first hexafluorophosphate synthesis reactors 105A, 105B, and 105C serves as an absorption reactor, in which metal fluoride and anhydrous hydrogen fluoride are added to absorb phosphorus pentafluoride from the gas discharged during the reaction of any one or both of the other reactors. After the hexafluorophosphate synthesis reactor acting as an absorption reactor has absorbed the gas from the other hexafluorophosphate synthesis reactors, any remaining phosphorus pentafluoride gas is added to the absorption reactor to obtain the product.

[0027] In this invention, the upper end of the first hexafluorophosphate synthesis reactor 105A is provided with an anhydrous hydrogen fluoride inlet 113A, a phosphorus source-metal source mixture inlet 114A, a gas phase inlet 111A, a gas phase outlet 110A, and a hydrogen chloride exhaust port 112A, and the lower end is provided with a discharge port 108A.

[0028] In this invention, the upper end of the second hexafluorophosphate synthesis reactor 105B is provided with an anhydrous hydrogen fluoride inlet 113B, a phosphorus source-metal source mixture inlet 114B, a gas phase inlet 111B, a gas phase outlet 110B, and a hydrogen chloride exhaust port 112B, and the lower end is provided with a discharge port 108B.

[0029] In this invention, the upper end of the third hexafluorophosphate synthesis reactor 105C is provided with an anhydrous hydrogen fluoride inlet 113C, a phosphorus source-metal source mixture inlet 114C, a gas phase inlet 111C, a gas phase outlet 110C, and a hydrogen chloride exhaust port 112C, and the lower end is provided with a discharge port 108C.

[0030] In this invention, the gas phase outlet of any one of the first hexafluorophosphate synthesis reactor 105A, the second hexafluorophosphate synthesis reactor 105B, and the third hexafluorophosphate synthesis reactor 105C can reach the bottom of the reactor through the gas phase inlets of the remaining two reactors.

[0031] In this invention, any one or two of the following reactors—the first hexafluorophosphate synthesis reactor 105A, the second hexafluorophosphate synthesis reactor 105B, and the third hexafluorophosphate synthesis reactor 105C—can be used as the other one or two reactors to absorb phosphorus pentafluoride gas containing unreacted phosphorus pentafluoride in hydrogen chloride gas. During the synthesis of hexafluorophosphate from anhydrous hydrogen fluoride and a phosphorus source-metal source, hydrogen chloride gas is generated. When the hydrogen chloride gas is discharged from the reactor, it carries unreacted phosphorus pentafluoride gas. One or two of the following reactors—the first hexafluorophosphate synthesis reactor 105A, the second hexafluorophosphate synthesis reactor 105B, and the third hexafluorophosphate synthesis reactor 105C—can be selected as reaction reactors, and one or two can be selected as absorption reactors for phosphorus pentafluoride gas containing unreacted phosphorus pentafluoride discharged during the hexafluorophosphate synthesis process. Metal fluoride and anhydrous hydrogen fluoride are added to the absorption reactor to absorb phosphorus pentafluoride gas containing unreacted phosphorus pentafluoride discharged during the reaction of any one or two of the other two reactors. In this invention, the hydrogen chloride exhaust ports of the first hexafluorophosphate synthesis reactor 105A, the second hexafluorophosphate synthesis reactor 105B, and the third hexafluorophosphate synthesis reactor 105C are used to discharge the hydrogen chloride gas after it has passed through the absorption reactor and absorbed the phosphorus pentafluoride gas containing unreacted phosphorus pentafluoride.

[0032] In this invention, the outer wall of the first hexafluorophosphate synthesis reactor 105A is provided with a first hexafluorophosphate synthesis reactor jacket 106A, the bottom of the first hexafluorophosphate synthesis reactor jacket 106A is provided with a first hexafluorophosphate synthesis reactor jacket refrigerant inlet 107A, and the upper part is provided with a first hexafluorophosphate synthesis reactor jacket refrigerant outlet 109A; the outer wall of the second hexafluorophosphate synthesis reactor 105B is provided with a second hexafluorophosphate synthesis reactor jacket 106B, the bottom of the second hexafluorophosphate synthesis reactor jacket 106B is provided with a second hexafluorophosphate synthesis reactor jacket refrigerant inlet 107B, and the upper part is provided with a second hexafluorophosphate synthesis reactor jacket refrigerant outlet 109B; the outer wall of the third hexafluorophosphate synthesis reactor 105C is provided with a third hexafluorophosphate synthesis reactor jacket 106C, the bottom of the third hexafluorophosphate synthesis reactor jacket 106C is provided with a third hexafluorophosphate synthesis reactor jacket refrigerant inlet 107C, and the upper part is provided with a third hexafluorophosphate synthesis reactor jacket refrigerant outlet 109C.

[0033] The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention further includes a metal source storage tank 101, a phosphorus source storage tank 102, and a screw feeder 103. The bottom outlets of the metal source storage tank 101 and the phosphorus source storage tank 102 are connected to the inlet of the screw feeder 103. The outlet of the screw feeder 103 is connected to the phosphorus source-metal source mixture inlet of each hexafluorophosphate synthesis reactor. Metering devices are installed on the pipelines between the bottom outlets of the metal source storage tank 101 and the phosphorus source storage tank 102 and the inlet of the screw feeder 103. Specifically, a first metering device 104A is installed on the pipeline between the bottom outlet of the metal source storage tank 101 and the inlet of the screw feeder 103, and a second metering device 104B is installed on the pipeline between the bottom outlet of the phosphorus source storage tank 102 and the inlet of the screw feeder 103.

[0034] In this invention, each hexafluorophosphate synthesis reactor is equipped with a gas phase inlet bottom pipe connected to the gas phase inlet. The gas phase inlet bottom pipe extends to the bottom of the hexafluorophosphate synthesis reactor and has multiple gas outlet holes.

[0035] In this invention, the first hexafluorophosphate synthesis reactor 105A is provided with a first hexafluorophosphate synthesis reactor gas phase inlet bottom pipe 117A that connects to the first hexafluorophosphate synthesis reactor gas phase outlet 110A, and the first hexafluorophosphate synthesis reactor gas phase inlet bottom pipe 117A is provided with a plurality of first hexafluorophosphate synthesis reactor gas outlet holes 118A.

[0036] In this invention, the second hexafluorophosphate synthesis reactor 105B is provided with a second hexafluorophosphate synthesis reactor gas phase inlet bottom pipe 117B that connects to the gas phase outlet 110B of the second hexafluorophosphate synthesis reactor, and the second hexafluorophosphate synthesis reactor gas phase inlet bottom pipe 117B is provided with a plurality of second hexafluorophosphate synthesis reactor gas outlet holes 118B.

[0037] In this invention, the third hexafluorophosphate synthesis reactor 105C is provided with a bottom pipe 117C for the gas phase inlet of the third hexafluorophosphate synthesis reactor, which is connected to the gas phase outlet 110C of the third hexafluorophosphate synthesis reactor. The bottom pipe 117C for the gas phase inlet of the third hexafluorophosphate synthesis reactor is provided with a plurality of gas outlet holes 118C of the third hexafluorophosphate synthesis reactor.

[0038] In this invention, each hexafluorophosphate synthesis reactor is provided with a mixture feed bottom pipe that connects to the phosphorus source-metal source mixture inlet. The mixture feed bottom pipe extends into the bottom of the hexafluorophosphate synthesis reactor and has multiple discharge holes.

[0039] In this invention, the first hexafluorophosphate synthesis reactor 105A is provided with a first hexafluorophosphate synthesis reactor mixture inlet pipe 115A that connects to the first hexafluorophosphate synthesis reactor phosphorus source-metal source mixture inlet 114A, and the first hexafluorophosphate synthesis reactor mixture inlet pipe 115A is provided with a plurality of first hexafluorophosphate synthesis reactor phosphorus source-metal source mixture outlet holes 116A.

[0040] In this invention, the second hexafluorophosphate synthesis reactor 105B is provided with a second hexafluorophosphate synthesis reactor mixture inlet pipe 115B that connects to the second hexafluorophosphate synthesis reactor phosphorus source-metal source mixture inlet hole 114B, and the second hexafluorophosphate synthesis reactor mixture inlet pipe 115B is provided with a plurality of second hexafluorophosphate synthesis reactor phosphorus source-metal source mixture outlet holes 116B.

[0041] In this invention, the third hexafluorophosphate synthesis reactor 105C is provided with a bottom inlet pipe 115C for feeding the mixture into the third hexafluorophosphate synthesis reactor, which is connected to the feed port 114C for the phosphorus source-metal source mixture of the third hexafluorophosphate synthesis reactor. The bottom inlet pipe 115C for feeding the mixture into the third hexafluorophosphate synthesis reactor is provided with a plurality of discharge holes 116C for the phosphorus source-metal source mixture of the third hexafluorophosphate synthesis reactor.

[0042] The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention includes several filtration and drying kettles, with at least one filtration and drying kettle provided. In this invention, the several filtration and drying kettles are two connected in parallel, namely a first filtration and drying kettle R-201A and a second filtration and drying kettle R-201B. Each filtration and drying kettle has a liquid phase inlet, a nitrogen inlet, and a gas phase outlet at its upper end, and is equipped with a thermometer, a pressure gauge, and a level gauge. At its lower end, it has a filtrate discharge port and a hexafluorophosphate powder discharge port. An internal stirring component is provided, and a filter screen is installed on the bottom inner wall. Each filtration and drying kettle is equipped with a heating mechanism. The hexafluorophosphate solid-liquid mixture discharge port at the lower end of the hexafluorophosphate synthesis kettle is connected to the liquid phase inlet at the upper end of the filtration and drying kettle. The heating mechanism is used to dry the hexafluorophosphate in the filtration and drying kettle, and can be achieved by electric heating, heat transfer oil, steam, or natural gas heating.

[0043] In this invention, the first filtration and drying vessel R-201A is provided with a first liquid phase inlet 202A, a first nitrogen inlet 203A and a first gas phase outlet 204A at its upper end, and is also provided with a first thermometer T-208A, a first pressure gauge P-209A and a first liquid level gauge L-210A. The lower end is provided with a first filtrate discharge port 205A and a first hexafluorophosphate powder discharge port 206A. The interior is provided with a first stirring device 207A, and the bottom inner wall is provided with a first filter screen 212A. The first filtration and drying vessel R-201A is equipped with a first heating mechanism E-211A.

[0044] In this invention, the upper end of the second filtration and drying vessel R-201B is provided with a second liquid phase inlet 202B, a second nitrogen inlet 203B, and a second gas phase outlet 204B, and is also provided with a second thermometer T-208B, a second pressure gauge P-209B, and a second liquid level gauge L-210B. The lower end is provided with a second filtrate discharge port 205B and a second hexafluorophosphate powder discharge port 206B. The interior is provided with a second stirring device 207B, and the bottom inner wall is provided with a second filter screen 212B. The second filtration and drying vessel R-201B is equipped with a second heating mechanism E-211B.

[0045] The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention includes a decomposition device E-213. One end of the decomposition device E-213 is provided with a hexafluorophosphate powder inlet, which is connected to the hexafluorophosphate powder outlet of a filtration and drying kettle. The other end is provided with a phosphorus pentafluoride gas outlet 216 and a metal fluoride powder outlet 217. The decomposition device E-213 is equipped with a heating mechanism; the decomposition device is a furnace, kiln, or kettle, and is equipped with a decomposition device thermometer T-214 and a decomposition device pressure gauge P-215. Continuous or intermittent feeding decomposition can be selected, utilizing electric heating, heat transfer oil, steam, or natural gas heating to decompose hexafluorophosphate into phosphorus pentafluoride gas; at least one decomposition device E-213 is provided.

[0046] In this invention, the filtration and drying vessel and the decomposition device are preferably connected via a metering device. The metering device preferably includes a volumetric or mass metering feeder.

[0047] In this invention, the metal fluoride powder outlet 217 of the decomposition device is connected to the inlet of the metal fluoride powder receiving tank.

[0048] In this invention, at least one fluoride powder receiving tank is provided. The upper end of the fluoride powder receiving tank is provided with a feed inlet and a pressure gauge, and the lower end is provided with a weighing module and a fluoride powder outlet 221.

[0049] In this invention, two metal fluoride powder receiving tanks are preferably provided, namely a first fluoride powder receiving tank V-218A and a second fluoride powder receiving tank V-218B. The first fluoride powder receiving tank V-218A is provided with a first fluoride powder receiving tank pressure gauge P-219A at its upper end and a first weighing module W-220A at its lower end. The second fluoride powder receiving tank V-218B is provided with a second fluoride powder receiving tank pressure gauge P-219B at its upper end and a second weighing module W-220B at its lower end.

[0050] The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention includes a compressor, a condenser, a phosphorus pentafluoride gas buffer tank, and a distillation column. In this invention, the phosphorus pentafluoride gas outlet 216 of the decomposition apparatus is sequentially connected to the compressor, the condenser, the phosphorus pentafluoride gas buffer tank, and the distillation column.

[0051] In this invention, the compressor is used to compress the phosphorus pentafluoride gas obtained from the decomposition device. The condenser is used to condense the compressed phosphorus pentafluoride gas. The distillation column is used to refine the condensed phosphorus pentafluoride gas.

[0052] The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention includes a target product synthesis vessel 301. The target product synthesis vessel 301 has a phosphorus pentafluoride gas inlet 308, a lithium fluoride inlet 307, a nitrogen inlet 305, and a circulation inlet 306 at its upper end, and a lithium hexafluorophosphate outlet 310 at its lower end. It contains a stirring component. The phosphorus pentafluoride gas inlet 308 is connected to the outlet of a phosphorus pentafluoride gas buffer tank. The target product synthesis vessel 301 is equipped with a cooling mechanism. A coil 316 is located at the upper end of the interior of the target product synthesis vessel 301, and multiple spray heads 304 are installed on the coil 316. A porous coil 312 is located inside the target product synthesis vessel 301, and the porous coil 312 is connected to the phosphorus pentafluoride gas inlet 308 via a pipe. Multiple evenly arranged exhaust holes 313 are provided on the wall of the porous coil 312. A deacidification column 303 is provided on the outside of the target product synthesis reactor 301. The deacidification column 303 contains deacidification resin 311. The inlet of the deacidification column 303 is connected to the lithium hexafluorophosphate outlet 310 at the lower end of the target product synthesis reactor 301. The outlet of the deacidification column 303 is connected to the coil 316 through the circulation inlet 306. A bottom external circulation pump 302 is provided on the pipe connecting the inlet of the deacidification column 303 and the lithium hexafluorophosphate outlet 310 at the lower end of the target product synthesis reactor 301. The cooling mechanism includes a target product synthesis reactor jacket 309 provided on the outer wall of the target product synthesis reactor 301. The bottom of the target product synthesis reactor jacket is provided with a target product synthesis reactor jacket refrigerant inlet 314, and the upper part is provided with a target product synthesis reactor jacket refrigerant outlet 315.

[0053] In this invention, the diameter of the exhaust port 313 is 0.2~3mm.

[0054] The liquid lithium hexafluorophosphate synthesis apparatus provided by the present invention also includes a concentration device, and the lithium hexafluorophosphate outlet 310 at the lower end of the target product synthesis vessel 301 is connected to the concentration device.

[0055] This invention provides a method for synthesizing liquid lithium hexafluorophosphate, using the apparatus described above for synthesizing liquid lithium hexafluorophosphate, and includes the following steps: Anhydrous hydrogen fluoride and a phosphorus source-metal source mixture are passed into the hexafluorophosphate synthesis reactor to react and obtain a hexafluorophosphate solid-liquid mixture and hydrogen chloride gas. The phosphorus source-metal source mixture is obtained by mixing a phosphorus source and a metal source. The solid-liquid mixture of hexafluorophosphate is fed into the filtration and drying kettle for solid-liquid separation and heating and drying to obtain hexafluorophosphate powder. The hexafluorophosphate powder is intermittently or continuously fed into the decomposition device for heating and decomposition to obtain phosphorus pentafluoride gas and metal fluoride powder. The metal fluoride powder is then used as a raw material for the synthesis of hexafluorophosphate. The phosphorus pentafluoride gas is compressed by a compressor and cooled by a condenser in sequence, and then enters a phosphorus pentafluoride gas buffer tank. It is then sent to a distillation column for purification to obtain purified phosphorus pentafluoride gas. Organic solvent and lithium fluoride are added to the target product synthesis vessel. Refined phosphorus pentafluoride gas is introduced into the target product synthesis vessel through the phosphorus pentafluoride gas inlet. After being vented through the exhaust port of the porous coil, it comes into contact with lithium fluoride to react. During the reaction, the stirrer and the bottom external circulation pump are turned on. The reaction solution in the target product synthesis vessel is deacidified and circulated through the deacidification column. The liquid returned to the target product synthesis vessel by the deacidification column is sprayed by the spray head. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis vessel. After the reaction is completed (i.e., the gas is introduced into the target product synthesis vessel (i.e., the refined phosphorus pentafluoride gas) is completed), liquid lithium hexafluorophosphate is obtained.

[0056] In this invention, the metal source includes one or more of sodium, lithium, potassium, calcium, and magnesium sources. The metal source is preferably a metal fluoride, and more preferably, it is a metal fluoride powder produced by the decomposition of hexafluorophosphate. In this invention, the metal source can be sodium fluoride and / or lithium fluoride. The phosphorus source preferably includes phosphorus pentachloride. The molar ratio of the metal source, phosphorus source, and anhydrous hydrogen fluoride is preferably 1:1.0~1.2:20~30, more preferably 1:1.1~1.2:20~30, and in the embodiments, it can be 1:1.1:24, 1:1.1:30, 1:1.2:30, 1:1.1:20, or 1:1.2:24.

[0057] In this invention, the hydrogen chloride gas generated in the hexafluorophosphate synthesis reactor is used to form concentrated hydrochloric acid. In this invention, the heating and drying are carried out in a filtration and drying reactor, during which hydrogen fluoride is also obtained, which is used in the hexafluorophosphate synthesis reactor for further reaction. The metal fluoride powder obtained by heating and decomposing the hexafluorophosphate powder in the decomposition device is preferably reused as a metal source.

[0058] In this invention, the preferred temperature for heating and drying is 20~150℃, and in the embodiments it can be 25℃, 30℃, 150℃ or 100℃.

[0059] In this invention, the temperature for the heating decomposition is preferably 200~600℃, more preferably 300~550℃, and in the embodiments it can be 500℃, 450℃, 330℃ or 360℃.

[0060] In this invention, the compression pressure is preferably 0.3~0.5MPa, and in the embodiment it can be 0.5MPa.

[0061] In this invention, the condensation temperature is preferably -25 to -40°C, and in the embodiment it can be -40°C.

[0062] In this invention, the preferred temperature for static placement is -60 to -40°C, and in the embodiment, it can be -60°C.

[0063] In this invention, the organic solvent includes one or more of dimethyl carbonate, ethyl methyl carbonate, methyl acetate, and ethyl acetate.

[0064] In this invention, the reaction temperature is preferably -10℃ to -15℃.

[0065] In this invention, after the reaction is completed, the resulting reaction solution is preferably concentrated to obtain the liquid lithium hexafluorophosphate. The concentration is preferably performed under a vacuum of -0.1 MPa and at a temperature of 20°C.

[0066] like Figure 1 As shown, the hexafluorophosphate synthesis reactor provided by this invention has metering tanks for a metal source and a phosphorus source above it. The phosphorus source and metal source are mixed evenly in a certain proportion using a screw feeder and then slowly fed into the hexafluorophosphate synthesis reactor. Anhydrous hydrogen fluoride reacts with the mixture of phosphorus and metal sources to generate hexafluorophosphate, which crystallizes in the anhydrous hydrogen fluoride. This reaction process produces hydrogen chloride gas, which carries a small amount of phosphorus pentafluoride gas when discharged. This gas phase is introduced into another hexafluorophosphate synthesis reactor containing metal fluoride and anhydrous hydrogen fluoride. The phosphorus pentafluoride gas in the hydrogen chloride gas containing unreacted phosphorus pentafluoride is then recovered and reused to generate hexafluorophosphate. The hydrogen chloride is then passed into pure water to produce concentrated hydrochloric acid. The reaction is essentially complete once the mixture of phosphorus and metal sources has been fully added. This device effectively improves the production efficiency of hexafluorophosphate by using a mixed feed of phosphorus and metal sources. Simultaneously, unreacted phosphorus pentafluoride gas is fed along with hydrogen chloride gas into an adjacent hexafluorophosphate synthesis reactor to recover and reuse the phosphorus pentafluoride, effectively improving the utilization rate of the phosphorus pentafluoride gas. The liquid lithium hexafluorophosphate synthesis apparatus provided by this invention includes a filtration and drying reactor, a hexafluorophosphate decomposition device, and a collection tank for collecting metal fluorides, such as... Figure 2As shown, a filter screen is installed inside the filtration and drying kettle to first filter out the liquid hydrogen fluoride in hexafluorophosphate. The remaining hexafluorophosphate is dried to obtain hexafluorophosphate powder. The hexafluorophosphate powder is intermittently or continuously fed to the decomposition device of hexafluorophosphate for heating and decomposition into phosphorus pentafluoride gas and metal fluoride powder. The metal fluoride powder is further recovered and reused as raw material. The liquid lithium hexafluorophosphate synthesis device provided by this invention achieves continuous gas production of the hexafluorophosphate decomposition device by switching the feed through multiple filtration and drying kettles. At the same time, this invention dries the hexafluorophosphate powder in the filtration and drying kettle before decomposition, producing only phosphorus pentafluoride gas and metal fluoride powder. Compared with the prior art, the phosphorus pentafluoride gas produced by this invention does not contain impurities such as hydrogen fluoride, hydrogen chloride, and phosphorus trifluoride, and the phosphorus pentafluoride gas obtained by this invention has higher purity. Figure 3 As shown, the target product synthesis vessel provided by this invention is equipped with a porous coil. Phosphorus pentafluoride gas is introduced into the solvent through the exhaust port of the porous coil to react with lithium fluoride, thereby improving the reaction efficiency. Simultaneously, a deacidification column is installed on the outside of the target product synthesis vessel. Through external circulation of the deacidification column, the liquid inside the target product synthesis vessel is pumped into the top of the vessel. After spraying, the phosphorus pentafluoride gas in the hollow part of the vessel is brought into contact with the liquid again for reaction, thus achieving complete reaction of the phosphorus pentafluoride gas introduced into the vessel. Through the external circulation of the deacidification column, this invention can further adsorb PPM-level hydrogen fluoride generated in liquid lithium hexafluorophosphate due to trace amounts of water in the lithium fluoride and organic solvent, thereby reducing the product acid value and improving product purity. Compared with the prior art, the prior art directly introduces phosphorus pentafluoride gas into the lithium fluoride solvent. The phosphorus pentafluoride gas forms a gas stream in the solution, passing through the solution to the upper cavity of the vessel, which cannot achieve a complete reaction. This invention utilizes a porous coil to prevent phosphorus pentafluoride gas from forming a gaseous flow in the solution, thereby improving reaction efficiency. Simultaneously, this invention employs external circulation in the deacidification column, through spraying, to ensure that unreacted phosphorus pentafluoride gas accumulating at the top of the target product synthesis vessel reacts completely. Therefore, the synthesis apparatus and method for liquid lithium hexafluorophosphate provided by this invention significantly improves the yield and purity of liquid lithium hexafluorophosphate production and effectively reduces the hydrogen fluoride content in liquid lithium hexafluorophosphate.

[0067] To further illustrate the present invention, the technical solutions provided by the present invention are described in detail below with reference to embodiments, but these should not be construed as limiting the scope of protection of the present invention. The following embodiments employ... Figure 1 , Figure 2 and Figure 3 The synthesis apparatus with the structure shown is used for production. The following embodiments are carried out according to... Figure 4 The synthesis was carried out according to the preparation process shown.

[0068] Example 1 This embodiment provides a method for synthesizing liquid lithium hexafluorophosphate, using the aforementioned liquid lithium hexafluorophosphate synthesis apparatus according to... Figure 4 The flowchart shown is synthesized.

[0069] (1) Sodium hexafluorophosphate synthesis process In this embodiment, anhydrous hydrogen fluoride from the storage tank is first pumped into the first hexafluorophosphate synthesis reactor 105A via a metering pump. Stirring is started, and the jacket temperature of the first hexafluorophosphate synthesis reactor 105A is maintained at -20~15℃. The mixed phosphorus pentachloride and sodium fluoride are slowly added to the first hexafluorophosphate synthesis reactor 105A via a screw feeder 103. The molar ratio of sodium fluoride, phosphorus pentachloride, and anhydrous hydrogen fluoride is 1:1.1:24. During the feeding process of the screw feeder 103, the hydrogen chloride generated in the first hexafluorophosphate synthesis reactor 105A and the unreacted phosphorus pentafluoride enter the second hexafluorophosphate synthesis reactor 105B, which contains a hydrogen fluoride solution with sodium fluoride, through the gas phase outlet 110A of the first hexafluorophosphate synthesis reactor. The phosphorus pentafluoride reacts further with the sodium fluoride in the second hexafluorophosphate synthesis reactor 105B to produce sodium hexafluorophosphate. The remaining hydrogen chloride gas is passed into water through the second hydrogen chloride exhaust port 112B to obtain concentrated hydrochloric acid.

[0070] After the reaction is completed, the material in the first hexafluorophosphate synthesis reactor 105A is pumped into the first filtration and drying reactor R-201A. The hydrogen fluoride liquid is removed by filtration in the first filtration and drying reactor R-201A. The obtained sodium hexafluorophosphate is heated to 100℃ and dried to obtain dry sodium hexafluorophosphate powder. Sodium hexafluorophosphate powder in the first filtration and drying kettle R-201A is intermittently fed to the decomposition device E-213 for heating and decomposition at a temperature of 500℃, yielding phosphorus pentafluoride gas and sodium fluoride powder. The phosphorus pentafluoride gas enters the phosphorus pentafluoride refining process, while the sodium fluoride powder is used as the sodium source for the synthesis of sodium hexafluorophosphate.

[0071] (3) Phosphorus pentafluoride gas refining process Phosphorus pentafluoride gas is compressed to 0.5 MPa by a compressor, condensed by a condenser (condensation temperature -40℃), and then enters a phosphorus pentafluoride buffer tank. It is then fed into a distillation column and distilled at -60℃ to obtain purified phosphorus pentafluoride gas.

[0072] (4) Liquid lithium hexafluorophosphate synthesis process Dimethyl carbonate solvent is pumped into the target product synthesis reactor 301. The reaction temperature is controlled at -10℃ by the chilled water in the jacket of the target product synthesis reactor 301. Stirring is started, and lithium fluoride enters the target product synthesis reactor 301 through the lithium fluoride inlet 307 under gravity. Then, the purified phosphorus pentafluoride gas enters the porous coil 312 of the target product synthesis reactor 301 through the phosphorus pentafluoride gas inlet 308. The purified phosphorus pentafluoride gas is introduced into the target product synthesis reactor 301 in the form of small bubbles. At the same time, the liquid material in the target product synthesis reactor 301 is pumped into the lower end of the deacidification column 303 through the bottom external circulation pump 302, and then pumped out from the upper end of the deacidification column 303 to the spray head 304 at the upper end of the target product synthesis reactor 301. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis reactor 301. After the phosphorus pentafluoride gas was circulated, initial liquid lithium hexafluorophosphate was obtained, and the generated lithium hexafluorophosphate was dissolved in dimethyl carbonate solvent.

[0073] (5) Liquid lithium hexafluorophosphate concentration process The initial liquid lithium hexafluorophosphate solution synthesized in step (4) is pumped to a concentration unit through a closed pipeline for concentration, and the dimethyl carbonate solvent is recovered. The vacuum pump is turned on to perform reduced pressure concentration, maintaining the vacuum degree in the concentration unit at -0.1 MPa. Low-temperature heat transfer oil is circulated in the jacket of the concentration unit to maintain the temperature at about 20°C. The condensate is recovered to the concentration solvent recovery tank, and the liquid lithium hexafluorophosphate of qualified concentration is pumped into the liquid lithium hexafluorophosphate finished product tank through a closed pipeline.

[0074] Example 2 This embodiment provides a method for synthesizing liquid lithium hexafluorophosphate, using the aforementioned liquid lithium hexafluorophosphate synthesis apparatus according to... Figure 4 The flowchart shown is synthesized.

[0075] (1) Sodium hexafluorophosphate synthesis process In this embodiment, anhydrous hydrogen fluoride from the storage tank is first pumped into the first hexafluorophosphate synthesis reactor 105A and the third hexafluorophosphate synthesis reactor 105C via a metering pump. Stirring is then started, and the jacket temperature of the first hexafluorophosphate synthesis reactor 105A and the third hexafluorophosphate synthesis reactor 105C is maintained at -20~15℃. The mixed phosphorus pentachloride and sodium fluoride are then slowly added to the first hexafluorophosphate synthesis reactor 105A and the third hexafluorophosphate synthesis reactor 105C via a screw feeder 103. The molar ratio of sodium fluoride, phosphorus pentachloride, and anhydrous hydrogen fluoride is 1:1.1:30. During the feeding process of the rotary feeder 103, the hydrogen chloride generated in the first hexafluorophosphate synthesis reactor 105A and the third hexafluorophosphate synthesis reactor 105C and the unreacted phosphorus pentafluoride enter the second hexafluorophosphate synthesis reactor 105B, which contains a hydrogen fluoride solution with sodium fluoride, through the gas phase outlet 110A and the third gas phase outlet 110C of the first hexafluorophosphate synthesis reactor. In the second hexafluorophosphate synthesis reactor 105B, the phosphorus pentafluoride reacts with the sodium fluoride to generate sodium hexafluorophosphate. The remaining hydrogen chloride gas is passed into water through the second hydrogen chloride exhaust port 112B to obtain concentrated hydrochloric acid.

[0076] After the reaction is completed, the materials in the first hexafluorophosphate synthesis reactor 105A and the third hexafluorophosphate synthesis reactor 105C are pumped into the first filter drying reactor R-201A and the second filter drying reactor R-201B. The hydrogen fluoride liquid is filtered out by the first filter drying reactor R-201A and the second filter drying reactor R-201B. Sodium hexafluorophosphate is heated to 150°C and dried to obtain dry sodium hexafluorophosphate powder. Sodium hexafluorophosphate powder in the first filter drying kettle R-201A and the second filter drying kettle R-201B is continuously fed to the decomposition device E-213 for heating and decomposition at a temperature of 450°C, yielding phosphorus pentafluoride gas and sodium fluoride powder. The phosphorus pentafluoride gas enters the phosphorus pentafluoride refining process, and the sodium fluoride powder is used as the sodium source for the synthesis of sodium hexafluorophosphate.

[0077] (3) Phosphorus pentafluoride gas refining process Phosphorus pentafluoride gas is compressed to 0.5 MPa by a compressor, condensed by a condenser (condensation temperature -40℃), and then enters a phosphorus pentafluoride buffer tank. It is then fed into a distillation column and distilled at -60℃ to obtain purified phosphorus pentafluoride gas.

[0078] (4) Liquid lithium hexafluorophosphate synthesis process Ethyl methyl carbonate solvent is pumped into the target product synthesis reactor 301. The reaction temperature is controlled at -10℃ by the chilled water in the jacket of the target product synthesis reactor 301. Stirring is started, and lithium fluoride enters the target product synthesis reactor 301 through the lithium fluoride inlet 307 under the action of gravity. Then, the purified phosphorus pentafluoride gas enters the porous coil 312 of the target product synthesis reactor 301 through the phosphorus pentafluoride gas inlet 308. The purified phosphorus pentafluoride gas is introduced into the target product synthesis reactor 301 in the form of small bubbles. At the same time, the liquid material in the target product synthesis reactor 301 is pumped into the lower end of the deacidification column 303 through the bottom external circulation pump 302, and then pumped out from the upper end of the deacidification column 303 to the spray head 304 at the upper end of the target product synthesis reactor 301. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis reactor 301. After the phosphorus pentafluoride gas was circulated, initial liquid lithium hexafluorophosphate was obtained, and the generated lithium hexafluorophosphate was dissolved in methyl ethyl carbonate solvent.

[0079] (5) Liquid lithium hexafluorophosphate concentration process In step (4), the initial liquid lithium hexafluorophosphate solution synthesized is pumped to a concentration unit through a closed pipeline for concentration, and the methyl ethyl carbonate solvent is recovered. The vacuum pump is turned on to perform reduced pressure concentration, maintaining a vacuum of -0.1 MPa in the concentration unit. Low-temperature heat transfer oil is circulated into the jacket of the concentration unit to maintain a temperature of about 20°C. The condensate is recovered to the concentration solvent recovery tank, and the obtained liquid lithium hexafluorophosphate of qualified concentration is pumped into the liquid lithium hexafluorophosphate finished product tank through a closed pipeline.

[0080] Example 3 This embodiment provides a method for synthesizing liquid lithium hexafluorophosphate, using the aforementioned liquid lithium hexafluorophosphate synthesis apparatus according to... Figure 4 The flowchart shown is synthesized.

[0081] (1) Lithium hexafluorophosphate synthesis process In this embodiment, anhydrous hydrogen fluoride from the storage tank is first pumped into the first hexafluorophosphate synthesis reactor 105A via a metering pump. Stirring is started, and the jacket temperature of the first hexafluorophosphate synthesis reactor 105A is maintained at -20~15℃. The mixed lithium fluoride and phosphorus pentachloride are slowly added to the first hexafluorophosphate synthesis reactor 105A via a screw feeder 103. The molar ratio of lithium fluoride, phosphorus pentachloride and anhydrous hydrogen fluoride is 1:1.2:30. During the feeding process of the screw feeder 103, the hydrogen chloride generated in the first hexafluorophosphate synthesis reactor 105A and the unreacted phosphorus pentafluoride enter the second hexafluorophosphate synthesis reactor 105B, which contains a hydrogen fluoride solution of lithium fluoride, through the gas phase outlet 110A of the first hexafluorophosphate synthesis reactor. The phosphorus pentafluoride reacts further with the lithium fluoride in the second hexafluorophosphate synthesis reactor 105B to generate lithium hexafluorophosphate. The remaining hydrogen chloride gas is passed into water through the second hydrogen chloride exhaust port 112B to obtain concentrated hydrochloric acid.

[0082] After the reaction is completed, the material in the first hexafluorophosphate synthesis reactor 105A is pumped into the first filtration and drying reactor R-201A. The hydrogen fluoride liquid is filtered out by the first filtration and drying reactor R-201A. The lithium hexafluorophosphate is heated to 150°C and dried to obtain dry lithium hexafluorophosphate powder. The lithium hexafluorophosphate powder in the filter drying kettle R-201A is continuously fed to the decomposition device E-213 for heating and decomposition at a temperature of 330℃, yielding phosphorus pentafluoride gas and lithium fluoride powder. The phosphorus pentafluoride gas enters the phosphorus pentafluoride refining process, while the lithium fluoride powder is used as the lithium source for the synthesis of lithium hexafluorophosphate.

[0083] (3) Phosphorus pentafluoride gas refining process Phosphorus pentafluoride gas is compressed to 0.5 MPa by a compressor, condensed by a condenser (condensation temperature -40℃), and then enters a phosphorus pentafluoride buffer tank. It is then fed into a distillation column and distilled at -60℃ to obtain purified phosphorus pentafluoride gas.

[0084] (4) Liquid lithium hexafluorophosphate synthesis process Ethyl acetate solvent is pumped into the target product synthesis reactor 301. The reaction temperature is controlled at -10°C by using chilled water in the jacket of the target product synthesis reactor 301. Stirring is started, and lithium fluoride enters the target product synthesis reactor 301 under gravity through the lithium fluoride inlet 307. Then, purified phosphorus pentafluoride gas enters the porous coil 312 of the target product synthesis reactor 301 through the phosphorus pentafluoride gas inlet 308. The purified phosphorus pentafluoride gas is introduced into the target product synthesis reactor 301 in the form of small bubbles. At the same time, the liquid material in the target product synthesis reactor 301 is pumped into the lower end of the deacidification column 303 through the bottom external circulation pump 302, and then pumped out from the upper end of the deacidification column 303 to the spray head 304 at the upper end of the target product synthesis reactor 301. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis reactor 301. After the phosphorus pentafluoride gas is circulated, the initial liquid lithium hexafluorophosphate is obtained, and the generated lithium hexafluorophosphate is dissolved in ethyl acetate solvent.

[0085] (5) Liquid lithium hexafluorophosphate concentration process In step (4), the initial liquid lithium hexafluorophosphate solution synthesized is pumped to a concentration unit through a closed pipeline for concentration, and the ethyl acetate solvent is recovered. The vacuum pump is turned on to perform reduced pressure concentration, maintaining the vacuum degree in the concentration unit at -0.1 MPa. Low-temperature heat transfer oil is circulated into the jacket of the concentration unit to maintain the temperature at approximately 20°C. The condensate is recovered to the concentration solvent recovery tank, and the obtained liquid lithium hexafluorophosphate of qualified concentration is pumped into the liquid lithium hexafluorophosphate finished product tank through a closed pipeline.

[0086] Example 4 This embodiment provides a method for synthesizing liquid lithium hexafluorophosphate, using the aforementioned liquid lithium hexafluorophosphate synthesis apparatus according to... Figure 4 The flowchart shown is synthesized.

[0087] (1) Lithium hexafluorophosphate synthesis process In this embodiment, anhydrous hydrogen fluoride from the storage tank is first pumped into the first hexafluorophosphate synthesis reactor 105A via a metering pump. Stirring is started, and the jacket temperature of the first hexafluorophosphate synthesis reactor 105A is maintained at -20~15℃. The mixed phosphorus pentachloride and lithium fluoride are slowly added to the first hexafluorophosphate synthesis reactor 105A via a screw feeder 103. The molar ratio of lithium fluoride, phosphorus pentachloride, and anhydrous hydrogen fluoride is 1:1.1:20. During the feeding process of the screw feeder 103, the hydrogen chloride generated in the first hexafluorophosphate synthesis reactor 105A and the unreacted phosphorus pentafluoride enter the second hexafluorophosphate synthesis reactor 105B, which contains a hydrogen fluoride solution with sodium fluoride, through the gas phase outlet 110A of the first hexafluorophosphate synthesis reactor. The phosphorus pentafluoride reacts further with the lithium fluoride in the second hexafluorophosphate synthesis reactor 105B to generate lithium hexafluorophosphate. The remaining hydrogen chloride gas is passed into water through the second hydrogen chloride exhaust port 112B to obtain concentrated hydrochloric acid.

[0088] After the reaction is completed, the material in the first hexafluorophosphate synthesis reactor 105A is pumped into the first filtration and drying reactor R-201A. The hydrogen fluoride liquid is filtered out by the first filtration and drying reactor R-201A. The lithium hexafluorophosphate is heated to 30°C and dried to obtain dry lithium hexafluorophosphate powder. In the first filtration and drying kettle R-201A, lithium hexafluorophosphate powder is intermittently transported to the decomposition device E-213 for heating and decomposition at a temperature of 330°C, yielding phosphorus pentafluoride gas and lithium fluoride powder. The phosphorus pentafluoride gas enters the phosphorus pentafluoride refining process, while the lithium fluoride powder is used as the lithium source for the synthesis of lithium hexafluorophosphate.

[0089] (3) Phosphorus pentafluoride gas refining process Phosphorus pentafluoride gas is compressed to 0.5 MPa by a compressor, condensed by a condenser (condensation temperature -40℃), and then enters a phosphorus pentafluoride buffer tank. It is then fed into a distillation column and distilled at -60℃ to obtain purified phosphorus pentafluoride gas.

[0090] (4) Liquid lithium hexafluorophosphate synthesis process Ethyl methyl carbonate solvent is pumped into the target product synthesis reactor 301. The reaction temperature is controlled at -10℃ by the chilled water in the jacket of the target product synthesis reactor 301. Stirring is started, and lithium fluoride enters the target product synthesis reactor 301 through the lithium fluoride inlet 307 under the action of gravity. Then, the purified phosphorus pentafluoride gas enters the porous coil 312 of the target product synthesis reactor 301 through the phosphorus pentafluoride gas inlet 308. The purified phosphorus pentafluoride gas is introduced into the target product synthesis reactor 301 in the form of small bubbles. At the same time, the liquid material in the target product synthesis reactor 301 is pumped into the lower end of the deacidification column 303 through the bottom external circulation pump 302, and then pumped out from the upper end of the deacidification column 303 to the spray head 304 at the upper end of the target product synthesis reactor 301. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis reactor 301. After the phosphorus pentafluoride gas was circulated, initial liquid lithium hexafluorophosphate was obtained, and the generated lithium hexafluorophosphate was dissolved in methyl ethyl carbonate solvent.

[0091] (5) Liquid lithium hexafluorophosphate concentration process In step (4), the initial liquid lithium hexafluorophosphate solution synthesized is pumped to a concentration unit through a closed pipeline for concentration, and the methyl ethyl carbonate solvent is recovered. The vacuum pump is turned on to perform reduced pressure concentration, maintaining the vacuum degree in the concentration unit at -0.1 MPa. Low-temperature heat transfer oil is circulated in the jacket of the concentration unit to maintain the temperature at approximately 20°C. The condensate is recovered to the concentration solvent recovery tank, and the obtained liquid lithium hexafluorophosphate of qualified concentration is pumped into the liquid lithium hexafluorophosphate finished product tank through a closed pipeline.

[0092] Example 5 This embodiment provides a method for synthesizing liquid lithium hexafluorophosphate, using the aforementioned liquid lithium hexafluorophosphate synthesis apparatus according to... Figure 4 The flowchart shown is synthesized.

[0093] (1) Lithium hexafluorophosphate synthesis process In this embodiment, anhydrous hydrogen fluoride from the storage tank is first pumped into the first hexafluorophosphate synthesis reactor 105A via a metering pump. Stirring is started, and the jacket temperature of the first hexafluorophosphate synthesis reactor 105A is maintained at -20~15℃. The mixed phosphorus pentachloride and lithium fluoride are slowly added to the first hexafluorophosphate synthesis reactor 105A via a screw feeder 103. The molar ratio of lithium fluoride, phosphorus pentachloride, and anhydrous hydrogen fluoride is 1:1.2:24. During the feeding process of the screw feeder 103, the hydrogen chloride generated in the first hexafluorophosphate synthesis reactor 105A and the unreacted phosphorus pentafluoride enter the second hexafluorophosphate synthesis reactor 105B, which contains a hydrogen fluoride solution with sodium fluoride, through the gas phase outlet 110A of the first hexafluorophosphate synthesis reactor. The phosphorus pentafluoride reacts further with the lithium fluoride in the second hexafluorophosphate synthesis reactor 105B to generate lithium hexafluorophosphate. The remaining hydrogen chloride gas is passed into water through the second hydrogen chloride exhaust port 112B to obtain concentrated hydrochloric acid.

[0094] After the reaction is completed, the material in the first hexafluorophosphate synthesis reactor 105A is pumped into the first filtration and drying reactor R-201A. The hydrogen fluoride liquid is filtered out by the first filtration and drying reactor R-201A. The lithium hexafluorophosphate is heated to 25°C and dried to obtain dry lithium hexafluorophosphate powder. In the first filtration and drying reactor R-201A, lithium hexafluorophosphate powder is intermittently transported to the decomposition device E-213 for heating and decomposition at a temperature of 360°C, yielding phosphorus pentafluoride gas and lithium fluoride powder. The phosphorus pentafluoride gas enters the phosphorus pentafluoride refining process, while the lithium fluoride powder is used as the lithium source for the synthesis of lithium hexafluorophosphate.

[0095] (3) Phosphorus pentafluoride gas refining process Phosphorus pentafluoride gas is compressed to 0.5 MPa by a compressor, condensed by a condenser (condensation temperature -40℃), and then enters a phosphorus pentafluoride buffer tank. It is then fed into a distillation column and distilled at -60℃ to obtain purified phosphorus pentafluoride gas.

[0096] (4) Liquid lithium hexafluorophosphate synthesis process Dimethyl carbonate solvent is pumped into the target product synthesis reactor 301. The reaction temperature is controlled at -10℃ by the chilled water in the jacket of the target product synthesis reactor 301. Stirring is started, and lithium fluoride enters the target product synthesis reactor 301 through the lithium fluoride inlet 307 under gravity. Then, the purified phosphorus pentafluoride gas enters the porous coil 312 of the target product synthesis reactor 301 through the phosphorus pentafluoride gas inlet 308. The purified phosphorus pentafluoride gas is introduced into the target product synthesis reactor 301 in the form of small bubbles. At the same time, the liquid material in the target product synthesis reactor 301 is pumped into the lower end of the deacidification column 303 through the bottom external circulation pump 302, and then pumped out from the upper end of the deacidification column 303 to the spray head 304 at the upper end of the target product synthesis reactor 301. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis reactor 301. After the phosphorus pentafluoride gas was circulated, initial liquid lithium hexafluorophosphate was obtained, and the generated lithium hexafluorophosphate was dissolved in dimethyl carbonate solvent.

[0097] (5) Liquid lithium hexafluorophosphate concentration process The initial liquid lithium hexafluorophosphate solution synthesized in step (4) is pumped to a concentration unit through a closed pipeline for concentration, and the dimethyl carbonate solvent is recovered. The vacuum pump is turned on to perform reduced pressure concentration, maintaining the vacuum degree in the concentration unit at -0.1 MPa. Low-temperature heat transfer oil is circulated in the jacket of the concentration unit to maintain the temperature at about 20°C. The condensate is recovered to the concentration solvent recovery tank, and the liquid lithium hexafluorophosphate of qualified concentration is pumped into the liquid lithium hexafluorophosphate finished product tank through a closed pipeline.

[0098] Comparative Example 1 A liquid lithium hexafluorophosphate sample was prepared according to the technical solution disclosed in Example 1 of the specification of Chinese Patent CN120829176A, "A method for preparing liquid lithium hexafluorophosphate from sodium hexafluorophosphate".

[0099] Table 1. Yields and purity of liquid lithium hexafluorophosphate prepared in Examples 1-5 and Comparative Example 1

[0100] As can be seen from the above examples and comparative examples, in Comparative Example 1, the method of Example 1 provided by Chinese Patent CN120829176A requires 5 days to synthesize a batch of liquid lithium hexafluorophosphate with a yield of 42%. Examples 1-5 of this invention require 3 days to prepare liquid lithium hexafluorophosphate with a yield of 85-92%. These examples demonstrate that this invention, through improvements to the liquid lithium hexafluorophosphate synthesis apparatus, significantly improves the production yield and purity of liquid lithium hexafluorophosphate, while also increasing the synthesis efficiency.

[0101] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An apparatus for synthesizing liquid lithium hexafluorophosphate, characterized in that, It includes a hexafluorophosphate synthesis reactor, several filtration and drying reactors, a decomposition device, a compressor, a condenser, a phosphorus pentafluoride gas buffer tank, a distillation column, and a target product synthesis reactor; At least two hexafluorophosphate synthesis reactors are provided. The upper end of each hexafluorophosphate synthesis reactor is provided with an anhydrous hydrogen fluoride inlet, a phosphorus source-metal source mixture inlet, a gas phase inlet, a gas phase outlet, and a hydrogen chloride exhaust port. The lower end is provided with a discharge port. The reactor is equipped with a stirring component and a cooling mechanism. The gas phase inlet and gas phase outlet of each hexafluorophosphate synthesis reactor are connected by a pipeline. The filtration and drying kettle is provided with a liquid phase inlet, a nitrogen inlet, and a gas phase outlet at the upper end, and a filtrate discharge port and a hexafluorophosphate powder discharge port at the lower end. It is equipped with a stirring component inside and a filter screen on the bottom inner wall. The filtration and drying kettle is equipped with a heating mechanism. The lower discharge port of the hexafluorophosphate synthesis kettle is connected to the upper liquid phase inlet of the filtration and drying kettle. The decomposition device is provided with a hexafluorophosphate powder inlet at one end, which is connected to the hexafluorophosphate powder outlet of the filter drying kettle, and a phosphorus pentafluoride gas outlet and a metal fluoride powder outlet at the other end. The decomposition device is equipped with a heating mechanism and is a furnace, kettle, or kiln. The phosphorus pentafluoride gas outlet of the decomposition device is sequentially connected to the compressor, the condenser, the phosphorus pentafluoride gas buffer tank, and the distillation column; The target product synthesis reactor is equipped with a phosphorus pentafluoride gas inlet and a lithium fluoride inlet at the upper end and a discharge port at the lower end. It contains a stirring component. The phosphorus pentafluoride gas inlet is connected to the outlet of the distillation column. The target product synthesis reactor is equipped with a cooling mechanism. A coil is located at the upper end of the reactor's interior, with multiple spray nozzles mounted on it. A porous coil is also located inside the reactor, connected to the phosphorus pentafluoride gas inlet via a pipe. Multiple evenly arranged exhaust holes are located on the wall of the porous coil. A deacidification column is located on the outside of the reactor. The inlet of the deacidification column is connected to the discharge port of the reactor, and the discharge port is connected to the coil. A bottom-circulation pump is installed on the pipe connecting the inlet of the deacidification column and the discharge port of the reactor.

2. The apparatus for synthesizing liquid lithium hexafluorophosphate according to claim 1, characterized in that, It also includes a metal source storage tank, a phosphorus source storage tank, and a screw feeder. The bottom outlets of the metal source storage tank and the phosphorus source storage tank are both connected to the inlet of the screw feeder. The outlet of the screw feeder is connected to the phosphorus source-metal source mixture inlet of each of the hexafluorophosphate synthesis reactors. Metering devices are provided on the pipelines between the bottom outlets of the metal source storage tank and the phosphorus source storage tank and the inlet of the screw feeder.

3. The apparatus for synthesizing liquid lithium hexafluorophosphate according to claim 1, characterized in that, Each of the hexafluorophosphate synthesis reactors is provided with a gas phase inlet bottom pipe connected to the gas phase inlet. The gas phase inlet bottom pipe extends to the inner bottom of the hexafluorophosphate synthesis reactor and is provided with multiple gas outlet holes.

4. The apparatus for synthesizing liquid lithium hexafluorophosphate according to claim 1, characterized in that, Each of the hexafluorophosphate synthesis reactors is provided with a mixture feed inlet pipe connected to the phosphorus source-metal source mixture inlet. The mixture feed inlet pipe extends into the bottom of the hexafluorophosphate synthesis reactor and has multiple discharge holes.

5. The apparatus for synthesizing liquid lithium hexafluorophosphate according to claim 1, characterized in that, The filtration and drying kettle is connected to the decomposition device via a metering device, which includes a volume or mass metering feeder; the metal fluoride powder outlet of the decomposition device is connected to the inlet of the fluoride powder receiving tank.

6. The apparatus for synthesizing liquid lithium hexafluorophosphate according to claim 1, characterized in that, The diameter of the exhaust port is 0.2~3mm.

7. The apparatus for synthesizing liquid lithium hexafluorophosphate according to claim 1, characterized in that, It also includes a concentration device, the outlet of which is connected to the target product synthesis vessel.

8. A method for synthesizing liquid lithium hexafluorophosphate, characterized in that, The synthesis of liquid lithium hexafluorophosphate using the apparatus described in any one of claims 1 to 7 includes the following steps: Anhydrous hydrogen fluoride and a phosphorus source-metal source mixture are passed into the hexafluorophosphate synthesis reactor to react and obtain a hexafluorophosphate solid-liquid mixture and hydrogen chloride gas. The phosphorus source-metal source mixture is obtained by mixing a phosphorus source and a metal source. The solid-liquid mixture of hexafluorophosphate is fed into the filtration and drying kettle for solid-liquid separation and heating and drying to obtain hexafluorophosphate powder. The hexafluorophosphate powder is intermittently or continuously fed into the decomposition device for heating and decomposition to obtain phosphorus pentafluoride gas and metal fluoride powder. The phosphorus pentafluoride gas is compressed by a compressor and cooled by a condenser in sequence, and then enters a phosphorus pentafluoride gas buffer tank. It is then sent to a distillation column for purification to obtain purified phosphorus pentafluoride gas. Organic solvent and lithium fluoride are added to the target product synthesis vessel. Refined phosphorus pentafluoride gas is introduced into the target product synthesis vessel through the phosphorus pentafluoride gas inlet. After being vented through the exhaust port of the porous coil, it comes into contact with lithium fluoride to react. During the reaction, the stirrer and the bottom external circulation pump are turned on. The reaction solution in the target product synthesis vessel is deacidified and circulated through the deacidification column. The liquid returned to the target product synthesis vessel by the deacidification column is sprayed by the spray head. The sprayed liquid reacts again with the unreacted phosphorus pentafluoride gas in the upper cavity of the target product synthesis vessel. After the reaction is completed, liquid lithium hexafluorophosphate is obtained.

9. The synthesis method according to claim 8, characterized in that, The metal source includes one or more of sodium, lithium, potassium, calcium and magnesium sources; the metal source is a metal fluoride, and the metal source is selected from the metal fluoride produced by the decomposition of hexafluorophosphate powder; the phosphorus source includes phosphorus pentachloride; the molar ratio of the metal source, phosphorus source and anhydrous hydrogen fluoride is 1:1.0~1.2:20~30.

10. The method for synthesizing liquid lithium hexafluorophosphate according to claim 8 or 9, characterized in that, The temperature for the thermal decomposition is 200~600℃; The organic solvent includes one or more of dimethyl carbonate, ethyl methyl carbonate, methyl acetate, and ethyl acetate.

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