CN103964409B

CN103964409B - High-purity LiPF6Manufacture method

Info

Publication number: CN103964409B
Application number: CN201310046724.5A
Authority: CN
Inventors: 斋藤克博; 大矢浩三; 片山慎介; 藤泽英仁; 三田真司
Original assignee: Kanto Denka Kogyo Co Ltd
Current assignee: Kanto Denka Kogyo Co Ltd
Priority date: 2013-02-05
Filing date: 2013-02-05
Publication date: 2018-04-10
Anticipated expiration: 2033-02-05
Also published as: CN103964409A

Abstract

A kind of high-purity LiPF is provided₆Manufacture method, specifically, the manufacture method makes to be dissolved in anhydrous hydrogen fluoride（AHF）In LiF with by AHF and phosphorus pentachloride（PCl₅）The PF of generation₅Reacted and generate LiPF₆, then implement crystallization, filtering and a series of operation of drying, it was found that suitably imposed a condition in each operation and be organically combined each operation, thus, it is possible to efficiently industry manufacture high-purity LiPF₆.In addition, it has been found that as process thereafter, sour gas is discharged with manufacture and is only absorbed by the water and captures first, when the superfluous sour gas that water can not fully absorb be present, further absorbed with aqueous slkali（For example, import alkali scrubber）And neutralisation treatment is carried out, thus it can be completely achieved innoxious.

Description

High-purity LiPF6Manufacture method

Technical field

In the field of secondary lithium batteries electrolyte, lithium lithium phosphate（LiPF₆）It is one of useful electrolyte.Closely Nian Lai, the high purity of electrolyte is pursued, and in the raising of social demand, it is necessary to carry out the mass production of electrolyte.This Invention be related to can efficiently industry manufacture high-purity LiPF₆Method and be related to can be by LiPF₆The sour gas discharged during manufacture Body continuously removes and carries out innoxious clean manufacture method, the LiPF of the high-purity₆What is used as electrolyte Undissolved composition, for example unreacted lithium fluoride in organic solvent（LiF）, the debris, the metal ingredient etc. that are mixed into raw material（With Lower is " unreacted LiF etc. "）For below 200ppm（Especially below 80ppm）, hydrogen fluoride（HF）It is 100ppm Deng acid ingredient Below（Especially below 80ppm）, moisture be below 10ppm（Especially below 8ppm）.

Background technology and problems to be solved by the invention

On LiPF₆Manufacture method, propose various methods all the time.

For example, in patent document 1, following method is described：Passing through phosphorus pentafluoride（PF₅）Reaction with LiF manufactures LiPF₆Method in, make PF₅Gas includes PF₅With hydrogen chloride（HCl）Gas contacted with the hydrofluoric acid solution comprising LiF, Reaction.This LiPF₆Preparation method be very effective from the viewpoint of reaction efficiency, but in recent years, in the neck of battery material LiPF is pursued in domain₆High-quality, therefore in order to tackle the market demand, it is necessary to supply the LiPF of more high-purity₆And The sour gas that continuous processing is discharged when manufacturing.

In patent document 2, disclosing makes with LiF and PCl₅And anhydrous hydrogen fluoride（It is designated as below " AHF "）As raw material institute The LiPF obtained₆Crystallization, and the method separated with solid product sedimentation device.Solid product sedimentation device is as separation Versatility is high for the device of solid and liquid, therefore the easy technology of manufacture method disclosed in patent document 2.However, LiPF₆In the case of the separation property difference of filtrate, LiPF can be turned into₆The easily state of attachment volume filtrate.Therefore, in follow-up work In the drying process of sequence, impurity is attached to LiPF₆The surface of crystal, make the LiPF as product₆Quality reduce.In recent years, exist LiPF is pursued in the field of battery material₆High-quality, therefore further carried to tackle the market demand, it is necessary to establish The filtering technique of the separation property of high crystal and filtrate.

In patent document 3, make with LiF, PCl₅And AHF is as LiPF obtained from raw material₆Crystallization, in vacuum after filtering Lower drying.This method is also industrially effective.However, in order to should be to the market demand, it is necessary to by the way that vacuum behaviour need not be carried out The method that make, is dried under the pressure atmosphere more than normal pressure obtains the LiPF that impurity reduces, quality more improves₆。

In patent document 4, PCl is added into AHF at -20 ~ -10 DEG C₅, so as to obtain lithium phosphoric acid（HPF₆）With AHF Mixture, and make HPF₆Reacted with LiF present in AHF at -40 ~ -20 DEG C, so as to obtain LiPF₆.This method due to PCl₅With the not PCl of remained unreacted in AHF reaction₅, therefore be effective, but PCl₅Bulk is easily become, therefore, it is difficult to slow Slow addition.On the other hand, in generation LiPF₆Reaction in, although reaction the starting stage can effectively eliminate it is unreacted LiF, but to reaction completion, in LiPF₆It is possible to be mixed into unreacted LiF in crystal during generation crystallization.

Therefore, in order in PCl₅With suppressing unreacted PCl in AHF reaction₅Residual, generation LiPF₆Reaction in not Remained unreacted LiF is, it is necessary to develop other methods.

In patent document 5, purified by rectifying HF, make itself and PCl₅React and generate PF₅, make PF₅It is anti-with LiF Should be so as to generating LiPF₆.In order to carry out LiPF₆High purity, HF distillation purifying is effective.In addition, in patent document 5, Generate LiPF₆Process in, in order to improve its yield, unreacted PF is imported to other LiF AHF solution₅。

Therefore, it is an object of the present invention to provide can efficiently industry manufacture high-purity LiPF₆Method, Yi Jiti It is described for can continuously be removed the sour gas discharged in the manufacturing process and carry out innoxious clean manufacture method The LiPF of high-purity₆The undissolved composition in the organic solvent that the electrolyte in as batteries such as lithium secondary batteries uses （Unreacted LiF etc.）For below 200ppm（Especially below 80ppm）, the acid ingredient such as HF be below 100ppm（Especially 80ppm Below）, moisture be below 10ppm（Especially below 8ppm）.

Prior art literature

Patent document 1：US Patent No.5,935,541

Patent document 2：CN102153064

Patent document 3：CN1124975C

Patent document 4：CN101723346B

Patent document 5：CN101570327

The content of the invention

The present invention relates to high-purity LiPF₆Manufacture method, it is characterised in that by PCl₅Middle addition AHF and generate PF₅Gas, make the PF₅Gas obtains including LiPF with the AHF solution reactions comprising LiF₆AHF solution, and from based on AHF Removed in the solution of composition undissolved to solution（Indissolubility）Foreign matter, then cooled down, thus made while stirring LiPF in solution₆Crystal separates out, and is separated by filtration LiPF with filter at low temperature₆Crystal, the pressure condition more than normal pressure The lower LiPF imported to gained₆Crystal is that inactive gas fully carries out liquid removal, and in inactive gas atmosphere Under with normal pressure, less than 50 DEG C sufficient condition remove crystal in HF, so as to obtain LiPF₆Crystal, and will be along with upper State LiPF₆Manufacturing process discharge sour gas absorb in aqueous alkali, water etc., without being discharged to outside system, by carrying Above-mentioned purpose is reached for this manufacture method.

It is different from patent document 4 in the present invention, PCl₅With in AHF reaction, by PCl₅Add AHF so as to The Form generation PF of gas₅, suppress unreacted PCl₅Residual.And then generate LiPF₆Reaction in, than LiPF₆Crystallization Make PF at the higher temperature of temperature₅Contacted with LiF with amount more than equivalent.Thus, not remained unreacted can be made in reaction solution LiF, suppress unreacted LiF and be mixed into LiPF as impurity₆Crystal in, can be achieved LiPF₆High purity.

In addition, there is the present invention HF without being crossed as foregoing patent document 5 using distillation purifying can obtain height The LiPF of purity₆The advantages of.And then according to the present invention, even in generation LiPF₆Process in other include LiF AHF it is molten Unreacted PF is imported in liquid₅, can also efficiently industry manufacture high-purity LiPF₆。

Embodiment

Hereinafter, to the high-purity LiPF of the present invention₆Manufacture method be described.

Specifically, the embodiment of manufacture method of the invention is a kind of LiPF₆Manufacture method, it includes following work Sequence：

（1) in the 1st container, to lithium fluoride（LiF）Middle addition anhydrous hydrogen fluoride（AHF）, so as to prepare comprising LiF's The process of AHF solution；

（2）In the 2nd container, to phosphorus pentachloride（PCl₅）Middle addition AHF, so as to generate comprising hydrogen chloride（HCl）PF₅ The process of gas；

（3）Make foregoing sequence（1）The obtained AHF solution and process comprising LiF（2）The PF for including HCl of generation₅Gas Reacted, so as to obtain including lithium lithium phosphate（LiPF₆）AHF solution process；

（4）From foregoing sequence（3）What is obtained includes LiPF₆AHF solution remove to the foreign matter of the solution indissolubility Process；

（5）Side stirring passes through foregoing sequence（4）What is obtained the eliminate foreign matter of indissolubility includes LiPF₆AHF it is molten Liquid side is cooled down, and thus makes LiPF₆The process that crystal separates out；

（6）To LiPF₆Crystal is nonactive and dew point is under less than -50 DEG C of gas atmosphere, with filter by before State process（5）LiPF obtaining, comprising precipitation₆The AHF solution of crystal carries out filter at low temperature, so as to separate LiPF₆Crystal and mother The process of liquid；

（7）By foregoing sequence（6）Obtained LiPF₆Crystal be nonactive to the crystal and dew point be less than -50 DEG C Under gas atmosphere, less than the 50 DEG C processes being dried；

（8）Make foregoing sequence（1）~（7）The sour gas of each operation discharge absorb process in water.

The LiPF₆Manufacture method especially include process（3）The HCl gases of discharge are absorbed in water and with the shape of hydrochloric acid The process of formula recovery.

And in process（8）It is middle superfluous sour gas to be present（Superfluous HCl gases etc.）, can not fully absorb in water In the case of, as subsequent processing, may also include：

（9）Make to pass through foregoing sequence（8）The sour gas process that contacts and neutralize with aqueous alkali,

In this case, there is provided according to above-mentioned（1）~（9）Process and manufacture LiPF₆Method.

Foregoing each operation is described in detailed below.

First, in the 1st container, AHF is added into LiF, so as to prepare the AHF solution comprising LiF（Process（1））.This When, if considering LiF to AHF solubility, AHF/LiF mol ratio is preferably more than 12 and less than 100.AHF/LiF's rubs Under conditions of that ratio is more than 100, meeting volume uses AHF, is undesirable in terms of financial cost.The operation is preferred More than -50 DEG C and less than 20 DEG C are carried out.Can also be by process（6）Filtrate after the filtering of middle gained uses as AHF.This When, if considering LiPF₆Recrystallization temperature, then filtrate is more than -50 DEG C of temperature.Therefore, it is used below -50 DEG C of temperature AHF is not suitable in terms of economic aspect and efficiency.Because the boiling point of AHF under atmospheric pressure is 20 DEG C, therefore more than 20 DEG C Under the conditions of can also be without using AHF.As AHF, the filtrate obtained by filter progress can be used（Include LiPF₆HF solution）, It can also prepare and filtrate component identical AHF solution（Include LiPF₆AHF solution）To use.It is although mixed in AHF Moisture can be to LiPF₆Yield have undesirable effect, if but in 50ppm or so, even if comprising also will not be to LiPF₆Quality Impact.

Then, PCl is added in the 2nd container₅, AHF is added thereto, and thus generation includes HCl PF₅Gas（Process （2））.Relative to the PCl of solid₅, can with adding liquid or the AHF of gas, but using gas AHF in the case of, it is necessary to profit The methods of with gasification process.It is different from the present invention, if adding the PCl of solid into AHF₅, then due to PCl₅It is to have consolidating for sublimability Body, accordingly, it is difficult to be added with certain speed into the AHF of liquid, causes local reaction to be generated heat, and thus causes distillation PCl₅, reaction intermediate with to subsequent processing, reaction efficiency reduce, as a result remaining unreacted LiF, reaction intermediate with LiF complex compound, therefore be undesirable.In addition, the PCl of solid is added into the AHF of liquid₅Method be difficult to control, have Cause the worry of runaway reaction, therefore there is also problem from the point of view of secure context.Preferably PCl₅It is fully converted to PF₅, therefore It is preferred that AHF/PCl₅Mol ratio be more than 5 and less than 50.AHF/PCl₅Mol ratio be less than 5 when, PCl₅As unreacting gas It is mixed into PF₅, turn into LiPF₆Purity reduce the reason for.In addition, AHF/PCl₅Mol ratio be less than 50 when reaction fully complete, Therefore raising effect is also had no more than 50 even if mol ratio.Reaction temperature is preferably more than -10 DEG C and less than 150 DEG C, in container Pressure be preferably more than normal pressure and 300kPa（abs）Below.Due to this reaction more than -10 DEG C and less than 150 DEG C are fully entered OK, therefore can not also implement under conditions of more than the scope.If container inner pressure is less than normal pressure, the AHF as solvent is waved Hair, therefore be undesirable from the point of view of economic aspect.Because this reaction is in 300kPa（abs）Fully carry out, therefore also may be used below Not more than 300kPa（abs）Pressure under implement.

In addition, herein, due to the PF of generation₅Contain HF mist with volume in gas, therefore preferably pass through gas-liquid Separator.As gas-liquid separator, as long as had no particular limits not the material corroded by AHF, can use commercially available product, Universal product.By the use of gas-liquid separator using HF as liquids recovery, it is reused in PCl with solid₅Contact, so as to make PCl₅ Fully reaction.If in addition, reclaiming and recycling the HF as mist, it is used to eliminate PCl₅Required AHF small amounts are Can solve, be preferred from the point of view of economic aspect.

It should be noted that implement process（1）With process（2）Order can also overturn.Added in the 1st container PCl₅, addition AHF, thus generation includes HCl PF₅Gas.Further, AHF is added to LiF in the 2nd container, so as to prepare AHF solution comprising LiF.Even if so exchange sequence is also possible.

Then, the PF of generation is made₅Gas is reacted with the LiF being dissolved in AHF（Process（3））.At this time, it may be necessary to will LiF is fully converted to LiPF₆, therefore PF₅/ LiF mol ratio is preferably more than 1 and less than 3.PF₅If/LiF mol ratio is less than 1, then reaction can not be completed fully, also LiF remainings., can be in the electrolyte as insoluble if there is unreacted LiF remainings Property composition and be mixed into the LiPF of final product₆In crystal, reduce purity, it is therefore desirable to LiF is reacted completely.In addition, generally Think that LiF and HF forms complex compound, if unreacted LiF volumes are present, in LiPF₆Crystallization when have HF also while be mixed into crystalline substance In body, make the increased tendency of the acid ingredient in crystal.Therefore, from reduction LiPF₆In acid ingredient from the viewpoint of, it is preferable And LiF is reacted completely.This reaction is in PF₅/ LiF mol ratio is fully completed when being less than 1.4, therefore can also be super Implement under conditions of crossing 1.4, but PF can be used superfluously₅, it is undesirable in economic aspect.Reaction temperature is preferably -20 DEG C Above and less than 20 DEG C, container inner pressure is preferably more than normal pressure and 200kPa（abs：Absolute pressure）Below.Reaction temperature is low When -20 DEG C of low temperature, the LiPF of generation₆Separate out, unreacted LiF is mixed into LiPF₆In crystal, therefore make LiPF₆Product Matter reduces.This reaction is fully carried out below 20 DEG C, therefore can not also be implemented under conditions of more than 20 DEG C.Pressure in container If power is less than normal pressure, so as to be separated out as the LiF of raw material, reaction can not be completed fully the AHF volatilizations as solvent.Due to this Reaction is in 200kPa（abs）Fully complete below, therefore can not also be more than 200kPa（abs）Under conditions of implement.

The PF for including HCl for reaction₅In gas, there is HF with the formal adjoint of gas and/or mist, thus it is preferably logical Supercooling condensed device, separated HF as liquid.It is and then adjoint as mist with the cooling liquefied HF of a condensed device part In HCl, therefore preferably pass through gas-liquid separator.As long as cool down the material that condensed device and gas-liquid separator are not corroded by AHF Just have no particular limits, the universal product that usually can be obtained can be used.It should be noted that process（2）In in order to from life Into PF₅When the mist that volume contains HF is separated in gas and using gas-liquid separator, same gas-liquid point can also be used with it From device.It is of course also possible to prepare other gas-liquid separators again.Using cooling condensed device HF is regard as liquid with gas-liquid separator Recovery, it is possible thereby to remain the amount as the AHF of LiF solvent necessarily in container.If as solvent AHF with HCl is shifted to outside container, then the LiF as raw material is separated out, and produces the state that reaction can not be completed fully.

After above-mentioned reaction, LiPF is included from gained₆AHF solution in remove using AHF as in the solution of principal component It is undissolved（Indissolubility）Foreign matter（Process（4））.The foreign matter of indissolubility refers to be mixed into the debris of raw material, pipe arrangement, machine Inside device because of abrasion and caused by organic matter, metal ingredient etc..These foreign matters are same with unreacted LiF to be used insoluble in electrolyte Organic solvent, it is therefore desirable that making LiPF₆Removed in advance before crystallization.The removal of foreign matter can be entered with known method OK, if but be less than 40 μm of filter using mesh, the transition to subsequent processing is steady.Particularly preferably use 5 ~ 35 μm of mesh Filter.

Cooled down in stirring when operation eliminates the solution of foreign matter as earlier mentioned, thus separated out LiPF₆'s Slurry（Process（5））.Now, the solution is preferably made to be cooled to the temperature less than -40 DEG C and more than -50 DEG C.More than -40 DEG C When, LiPF₆Yield is low, producing rate variance.At a temperature of less than -50 DEG C, big energy is needed in order to be cooled down, is being passed through It is undesirable in terms of Ji.

In order to be separated by filtration obtained LiPF₆Crystal, under the atmosphere of non-active gas, slurry is moved into filter, Pressurizeed or centrifugal filtration, thus remove liquid（Process（6））.The operation is preferably more than -50 DEG C and less than -10 DEG C are entered OK.At a temperature of more than -10 DEG C, crystal can be dissolved in the mother liquor for being attached to the crystal and yield reduces.Less than -50 At a temperature of DEG C, big energy is needed in order to be cooled down, is undesirable in economic aspect.In order to remove liquid well Body, in the case of pressure filtration, the non-active gas in filter are preferably blown into as more than normal pressure and 0.2MPa（abs）With Under, in the case of centrifugal filtration, preferably centrifugal acceleration is 4900m/s²Above and 14700m/s²Below.Pressure ratio normal pressure is low When, AHF volatilizees and makes the LiPF for including impurity₆Separate out, thus it is not preferred.In order to more than 0.2MPa（abs）Under conditions of it is real Apply, it is necessary to assign intensity to filter, therefore be undesirable in economic aspect.Centrifugal acceleration is less than 4900m/s²When, It is insufficient to remove liquid, more than 14700m/s²When, it is necessary to using high price device, therefore be undesirable in economic aspect.Separately Outside, as long as non-active gas dew point is less than -50 DEG C, to LiPF₆For inactive gas, there is no particular limitation, Such as it can include comprising selected from air, nitrogen, helium, argon, neon, phosphorus trifluoride（PF₃Gas）In at least one kind of gas.

By the crystal under same non-active gas atmosphere, less than 50 DEG C be dried（Process（7））.As temperature, Normal temperature is preferable in economic aspect.At a temperature of more than 50 DEG C, due to LiPF₆Rapidly decompose, therefore be undesirable.Pressure Power is that normal pressure is enough.Needed under vacuum condition compared with multi-energy, therefore be undesirable in economic aspect.Drying time is preferably More than 1 hour.If less than 1 hour, HF can not be fully removed sometimes.

LiPF on the present invention₆Manufacture method, after the sour gas discharged in each operation is absorbed in water（Process （8））, contact and neutralize with aqueous alkali（Process（9））, it is possible thereby to not discharged to outside system.Sour gas is set to absorb in water In after the use of the such order of aqueous alkali is preferable from the viewpoint of the processing of discharge gas, there is provided clean manufacture Method.The PF as sour gas is generated in each operation₅Gas, PF₃Gas, HCl gases, HF gases, POF₃Gas etc.. On making these sour gas absorb the method in water, as long as sour gas can be made fully to be contacted with water, then it can use and appoint Meaning method.Trapped gas and it can from the upper side sprinkle water by being blown into gas into water, in regulation space, make gas and water pair Stream or cocurrent and contact such various methods to carry out.As aqueous alkali, lithium hydroxide can be included（LiOH）, hydrogen Sodium oxide molybdena（NaOH）, sodium carbonate（Na₂CO₃）, sodium acid carbonate（NaHCO₃）, potassium hydroxide（KOH）, potassium carbonate（K₂CO₃）, bicarbonate Potassium（KHCO₃）, calcium hydroxide（Ca(OH)₂）, magnesium hydroxide（Mg(OH)₂）, calcium carbonate（CaCO₃）Any of or mixture The aqueous solution.

In addition, the LiPF obtained by using the method for the present invention₆The undissolved composition in the organic solvent of electrolyte（Not LiF of reaction etc.）Can be reduced to the acid ingredients such as below 200ppm, especially below 80ppm, HF can be reduced to below 100ppm, In particular below 80ppm, moisture can be reduced to below 10ppm, in particular below 8ppm, turn into the LiPF of high-purity₆。

Embodiment

Hereinafter, embodiments of the invention and comparative example are enumerated, but the present invention is not restricted by the embodiments.Wherein, The summary of experimental result is shown in table 1 in the lump.

[embodiment 1]

Process（1）：130g LiF are put into the reactor with mixer and cooling jacket of 5L capacity（Solid, solid）, by internal cooling to 0 DEG C, 2850g AHF are slowly added to when being stirred to it（Liquid, liquid）, solution is made.

Process（2）：Then, 1357g PCl are put into the reactor with cooling jacket of another 10L capacity₅（Gu Body, solid）, it is slowly added to 780gAHF（Liquid, liquid）.So as to 200kPa is kept in system（abs）Below and 50 DEG C with Under mode change AHF adding speed, so as to adjust the PF comprising HCl₅The yield of gas.

Process（3）：By process（2）The PF for including HCl of middle generation₅Gas imports foregoing 5L reactors.Pressed from both sides to cooling It is passed through cold water in set to be adjusted, the scope that the temperature for making the solution in system is 0 ~ 20 DEG C.Will be along with PF₅The HCl of gas The system of gas discharge reactor is outer and makees disinfection.By process（2）The PF for including HCl of middle generation₅Gas all imports After the completion of, terminate to react in the near future.

Process（4）：Filter by the reaction solution of gained by 5 μm of nominal filter fineness, so as to remove to based on AHF The reaction solution of composition is the foreign matter of indissolubility.

Process（5）：By the PFA containers with mixer of solution input 5L capacity, -50 are cooled in agitating solution DEG C, so as to separated out LiPF₆Slurry.

Process（6）：The SUS filters with cooling jacket of 5L capacity are cooled to -50 DEG C, import above-mentioned slurry, In 0.17MPa（abs）Under be blown into the nitrogen below -50 DEG C of dew point so as to remove filtrate.After the operation terminates, the acid of gained crystal Property composition is 183ppm.

Process（7）：The crystal is put into the container with heating jacket of 1L capacity, in 50 DEG C of tepidariums, argon atmospher Under heated.After 3 hours, LiPF is determined₆In acid ingredient, in an amount of from 80ppm, therefore terminate drying.

Process（8）：The sour gas of discharge is blown into water and absorbed.

Process（9）：Though unconfirmed arrive process（8）In the sour gas that does not fully absorb, but still further the gas is led Enter alkali and remove washer.

228gLiPF is reclaimed in operation more than₆.Moisture in the crystal is 8ppm.Its insoluble composition is 70ppm. It should be noted that insoluble composition herein refers to, by 10gLiPF₆Dissolution of crystals using usually as electrolyte 1,2- dimethoxy-ethanes（DME）In 150mL, insoluble composition is separated by filtration（Use 0.2 μm of molecular filter）When it is insoluble Composition.

[embodiment 2]

Process（1）：39g LiF are put into the reactor with mixer and cooling jacket of 5L capacity（Solid, solid）, by internal cooling to 0 DEG C, it is slowly added to 3300g thereto while stirring and includes 533g LiPF₆AHF solution be made Solution, and then 82gAHF is added, stop stirring when solid constituent disappears.

Process（2）：Then, 625g PCl are put into the reactor with cooling jacket of another 5L capacity₅（Solid, solid）, it is slowly added to 360g AHF（Liquid, liquid）.So as to 200kPa is kept in system（abs）Below and less than 50 DEG C Mode change AHF adding speed, so as to adjust the PF comprising HCl₅The yield of gas.

Process（4）：Filter by the reaction solution of gained by 35 μm of nominal filter fineness, so as to remove to using AHF as The reaction solution of principal component is the foreign matter of indissolubility.

Process（6）：The SUS filters with cooling jacket of 5L capacity are cooled to -50 DEG C, import above-mentioned slurry, In 0.17MPa（abs）Under be blown into the nitrogen below -50 DEG C of dew point so as to remove filtrate.After the operation terminates, the acid of gained crystal Property composition is 235ppm.

Process（7）：The crystal is put into the container with heating jacket of 1L capacity, in 50 DEG C of tepidariums, argon atmospher Under heated.After 3 hours, LiPF₆In acid ingredient be 75ppm, therefore terminate drying.

Process（8）：The sour gas of discharge is blown into water and absorbed.

Process（9）：Due to confirming process（8）In the sour gas that does not fully absorb be 110ppm, therefore removed in alkali Neutralized in washer.Sour gas unconfirmed is arrived in the exit that washer is removed in alkali.

228gLiPF is reclaimed in operation more than₆.Moisture in the crystal is 7ppm.It is in addition, insoluble in crystal Composition is 77ppm.

[embodiment 3]

Process（2）：Then, 1357g PCl are put into the reactor with cooling jacket of another 10L capacity₅（Gu Body, solid）, it is slowly added to 780gAHF（Liquid, liquid）.So as to 200kPa is kept in system（abs）Below and 50 DEG C with Under mode change AHF adding speed, so as to adjust the PF comprising HCl₅The yield of gas.In addition, should using being arranged on The gas-liquid separator in the exit of 10L reactors, from the PF for including HCl generated by reaction₅Remove in gas and accompany with it The mist using HF as principal component.Using being filled with 44g Raschig rings in gas-liquid separator（Raschig ring）（Diameter 5mm, length Spend 5mm, thickness 0.4mm）Pipe（Internal diameter 20mm, length 100mm）.

Process（3）：By process（2）The PF for including HCl for eliminating mist of middle generation₅Gas imports process（1) 5L Reactor, make the PF for including HCl₅Gas and LiF AHF solution are reacted.It is passed through in the cooling jacket subsidiary to reactor Cold water is adjusted, the scope that the temperature for making the solution in reactor system is 0 ~ 20 DEG C.Confirm process（2）The bag of middle generation PF containing HCl₅After the completion of gas all imports, terminate reaction.The HCl gases for having neither part nor lot in reaction are discharged simultaneously to outside reactor system Remove.Now, by the HCl gases of discharge by cooling down condensed device and process（2）The different gas-liquid of the middle gas-liquid separator that uses Separator, HF adjoint in the discharge gas is reclaimed as liquid.The HF of recovery sends reactor back to.

Process（6）：The SUS filters with cooling jacket of 5L capacity are cooled to -50 DEG C, import above-mentioned slurry, In 0.17MPa（abs）Under be blown into the nitrogen below -50 DEG C of dew point so as to remove filtrate.After the operation terminates, the acid of gained crystal Property composition is 179ppm.

Process（7）：The crystal is put into the container with heating jacket of 1L capacity, in 50 DEG C of tepidariums, argon atmospher Under heated.After 3 hours, LiPF is determined₆In acid ingredient, in an amount of from 77ppm, therefore terminate drying.

Process（8）：The sour gas of discharge is blown into water and absorbed.

232gLiPF is reclaimed in operation more than₆.Moisture in the crystal is 7ppm.It is in addition, insoluble in crystal Composition is 70ppm.

[comparative example 1]

Comparative example 1 and the process of embodiment 1（2）It is different.The process for describing comparative example 1 below.

Process（1）：130g LiF are put into the reactor with mixer and cooling jacket of 5L capacity（Solid, solid）, by internal cooling to 0 DEG C, 2850g AHF are slowly added to when being stirred to it（Liquid, liquid）, solution is made. Stop stirring when solid constituent disappears.

Process（2’）：Then, 780gAHF is put into the reactor with cooling jacket of another 10L capacity（Liquid, liquid）, it is slowly added to 1357g PCl₅（Solid, solid）.Although attempt so as to keep 200kPa in system（abs）Below, And less than 50 DEG C of mode changes PCl₅Adding speed, so as to adjust the PF comprising HCl₅The yield of gas, but be difficult to adjust Adding speed, sometimes the temperature in system rise to 80 DEG C.PCl is added into AHF₅Reaction is unmanageable, heterogeneity and office Occur to portion, it can thus be assumed that the temperature in system is partially raised above PCl₅Sublimation point temperature.

Process（3）：By process（2）The PF for including HCl of middle generation₅Gas imports foregoing 5L reactors.Hereinafter, with reality Apply example 1 and carry out same operation, process（6）Operation terminate after, the acid ingredient of the crystal of gained is 374ppm.

Process（7）：The crystal is put into the container with heating jacket of 1L capacity, in 50 DEG C of tepidariums, argon atmospher Under heated.After 3 hours, LiPF₆In acid ingredient be 105ppm, therefore terminate drying.

188gLiPF is reclaimed in operation more than₆.Moisture in the crystal is 10ppm.It does not dissolve composition 298ppm。

[comparative example 2]

Comparative example 2 and the process of embodiment 1（6）It is different.The process for describing comparative example 2 below.

From process（1）To process（5）Operate and carry out similarly to Example 1.

Process（6’）：In room temperature（24℃）Under, using the PTFE filters of 5L capacity, import until process（5）Institute The slurry obtained, in 0.17MPa（abs）The lower nitrogen imported below -50 DEG C of dew point is so as to removing mother liquor.The filter operation terminates Afterwards, the acid ingredient of gained crystal is 215ppm.

Process（7）：The crystal is put into the container with heating jacket of 1L capacity, in 50 DEG C of tepidariums, argon atmospher Under heated.After 3 hours, LiPF₆In acid ingredient be 99ppm, therefore terminate drying.

146gLiPF is reclaimed in operation more than₆.Moisture in the crystal is 18ppm.It does not dissolve composition 496ppm。

[table 1]

Table 1 " experimental result "

	Receipts amount *（Yield Li converts）	Acid ingredient	Moisture	Insoluble composition
					Embodiment 1	228g（30%）	80ppm	8ppm	70ppm
Embodiment 2	228g（30%）	75ppm	7ppm	77ppm
					Embodiment 3	232g（31%）	77ppm	7ppm	70ppm
Comparative example 1	188g（25%）	105ppm	12ppm	298ppm
					Comparative example 2	146g（19%）	99ppm	18ppm	496ppm

*：Yield represents LiPF₆Relative to process（1）The LiF of middle input, the ratio in terms of Li conversions.

The effect of invention

According to the LiPF of the present invention₆Manufacture method, can efficiently industry manufacture high-purity LiPF₆, the high-purity LiPF₆To the insoluble composition of the organic solvent used as electrolyte（Unreacted LiF etc.）For acid such as below 200ppm, HF Property composition is below 100ppm, moisture is below 10ppm.

Claims

A kind of 1. LiPF₆Manufacture method, it includes following process：

(1) in the 1st container, anhydrous hydrogen fluoride AHF is added into lithium fluoride LiF, so as to prepare the AHF solution comprising LiF Process；

(2) in the 2nd container, to phosphorus pentachloride PCl₅Middle addition AHF, so as to generate the PF for including hydrogen chloride HCl₅The work of gas Sequence；

(3) the AHF solution comprising LiF that the process (1) obtains and the PF for including HCl of process (2) generation are made₅Gas is carried out Reaction, so as to obtain including LiPF₆AHF solution process；

(4) LiPF is included from what the process (3) obtained₆AHF solution remove process to the foreign matter of the solution indissolubility；

(5) foreign matter for eliminating indissolubility that side stirring is obtained by the process (4) includes LiPF₆AHF solution side enter Row is cooled to the temperature less than -40 DEG C and more than -50 DEG C, thus makes LiPF₆The process that crystal separates out；

(6) to LiPF₆Crystal is nonactive and dew point is under less than -50 DEG C of gas atmosphere, with filter by the process (5) LiPF obtaining, comprising precipitation₆The AHF solution of crystal carries out filter at low temperature, so as to separate LiPF₆The work of crystal and mother liquor Sequence；

(7) LiPF for obtaining the process (6)₆Crystal is being nonactive to the crystal and dew point is less than -50 DEG C of gas gas Under atmosphere, less than the 50 DEG C processes being dried；

(8) sour gas for discharging each operation of the process (1)~(7) absorbs the process in water,

(9) process to neutralize is contacted with aqueous alkali by the sour gas of process (8).
2. LiPF according to claim 1₆Manufacture method, it is characterised in that in process (2), to PCl₅Middle addition is relative In PCl₅PF is completed for more than equivalent AHF₅The reaction of formation of gas, not to the later each work of process (3) and process (3) The PCl of conveying or remained unreacted in sequence₅, reaction intermediate.
3. LiPF according to claim 1₆Manufacture method, it is characterised in that make generation in process (2) comprising HCl PF₅Gas, so as to remove the adjoint mist using HF as principal component of the gas, is then eliminated this by gas-liquid separator The PF for including HCl of mist₅Gas is used in process (3).
4. LiPF according to claim 1₆Manufacture method, it is characterised in that in process (3), by the adjoint HF of HCl Cool down it is condensing reclaim, and then use HF adjoint gas-liquid separator recovery HCl.
5. LiPF according to claim 1₆Manufacture method, it is characterised in that in process (3), be using relative to LiF PF more than equivalent₅Gas, thus not into subsequent handling conveying or remained unreacted LiF.
6. LiPF according to claim 1₆Manufacture method, it is characterised in that in process (6), the bar below -10 DEG C Filter operation is carried out under part.
7. LiPF according to claim 1₆Manufacture method, it is characterised in that pair of process (6) and/or process (7) LiPF₆Crystal is that inactive gas refers to, includes at least one kind of gas in air, nitrogen, helium, argon, neon, phosphorus trifluoride Body.
8. LiPF according to claim 1₆Manufacture method, it is characterised in that filter in process (6) have plus Any of press filtration and centrifugal filtration or two kinds of functions.
9. LiPF according to claim 1₆Manufacture method, it is characterised in that inhale the HCl gases of discharge in process (3) It is received in water and is reclaimed in the form of hydrochloric acid.
10. LiPF according to claim 1₆Manufacture method, it is characterised in that as the aqueous alkali of process (9), make With lithium hydroxide, sodium hydroxide, sodium carbonate, sodium acid carbonate, potassium hydroxide, potassium carbonate, saleratus, calcium hydroxide, hydroxide The aqueous solution of any of magnesium, calcium carbonate or mixture.