A kind of lithium hexafluoro phosphate prepares purification process
Technical field
The invention belongs to power lithium-ion battery manufacturing technology field, the system of specifically a kind of electrolytic salt lithium hexafluoro phosphate
Standby purification process.
Background technique
Lithium ion battery has operating voltage height, energy density big (light-weight), self-discharge rate bottom, memory-less effect, follows
Outstanding advantages of ring service life is long and pollution-free, has captured rapidly many fields with the incomparable advantage of other batteries, extensively
Applied in the products such as well known mobile phone, laptop, miniature camera, electric car, with electronic vapour
The industrialization of vehicle, dosage are bound to increasing.Using showing that lithium ion battery is a kind of ideal small-sized green power supply.And six
Lithium fluophosphate is the key core material for manufacturing lithium ion battery, is most popular electrolyte in commercial lithium-ion batteries
Lithium salts has excellent chemical property, and ionic conductivity is good, and dissolubility in organic solvent is good, has fabulous application
With environmental properties.
Important electrolytic salt of the lithium hexafluoro phosphate as lithium-ion battery electrolytes, it is desirable that it is (logical with very high purity
Often otherwise it is lower than 99.5%), impurity therein such as moisture content, alkali metal, heavy metal and other impurity such as PCl3And POCl3's
Content must be strictly controlled, and otherwise will lead to internal resistance of cell increase, battery capacity decaying is fast, and cycle life shortens, or even influences
The safety of battery.Therefore, the lithium hexafluoro phosphate product for obtaining the objectionable impurities of high-purity and low content is of great significance.
CN102009972A discloses a kind of preparation method of lithium hexafluoro phosphate, includes the following steps: that (1) is obtained by distillation
Purity is obtained in the hydrogen fluoride liquid of 99.99wt% or more;(2) high-purity hydrogen fluoride liquid is made to react to obtain five fluorine with phosphorus pentachloride
Change the mixed gas of phosphorus and hydrogen chloride;(3) mixed gas of fluoride-free phosphorus and hydrogen chloride is passed into hydrogen fluoride and lithium fluoride,
Make to react under certain temperature and pressure and lithium hexafluorophosphate solution is made, hydrogen chloride gas timing is discharged and is made after water absorbs
By-product hydrochloric acid;(4) Crystallization Separation: being filtered lithium hexafluorophosphate solution, and filtrate is sent into partial crystallization slot, in temperature
At -70 DEG C -80 DEG C, lithium hexafluoro phosphate is precipitated, filtering, obtains lithium hexafluoro phosphate production with secondary drying through level-one is dry
Product, wherein residual fluorinated hydrogen is also replaced using nitrogen.
It is low that there are crystalline rates in above-mentioned technology;It needs by being dried twice, the consuming time is longer, takes time and effort;
Moisture content needs the disadvantages of being further decreased.
Summary of the invention
For this purpose, technical problem to be solved by the present invention lies in provide a kind of lithium hexafluoro phosphate to prepare purification process.This
The preparation method simple process and low cost of invention, products obtained therefrom purity is high.
In order to achieve the above object, the present invention uses following technological means:
A kind of lithium hexafluoro phosphate prepares purification process, includes the following steps:
(1) PF is utilized5, LiF, hydrogen fluoride lithium hexafluorophosphate solution is prepared;
(2) lithium hexafluorophosphate solution obtained by step (1) is removed into micro insoluble impurities, solution is sent to crystallizing evaporator
In, heating evaporates partially fluorinated hydrogen;
(3) when evaporating liquid level to initial liquid level 1/3~2/3, stop evaporation, be cooled to -20~-40 according to temperature gradient
DEG C, for example, -23 DEG C, -29 DEG C, -33 DEG C, -36 DEG C, -39 DEG C etc., cooling terminates, and hexafluorophosphoric acid crystalline lithium is precipitated, and is obtained by filtration
The first product of lithium hexafluoro phosphate obtains target product lithium hexafluoro phosphate after purification.It is molten if evaporate the amount of liquid more than 2/3
Other in liquid, which are not easy the substance being precipitated, can also be precipitated, and cause crystal impure;When evaporating amount of liquid and being far smaller than 1/3, crystallization
Quantity will decline, and lead to the reduction of single batch crystal weight, and therefore, present invention selection is evaporated to initial liquid level 1/3~2/3.
The crystallizer used in purification process for preparing of lithium hexafluoro phosphate of the invention is different from general static mold,
A kind of crystallizer for integrating evaporative crystallization, separation of solid and liquid, solvent recovery, crystallization temperature most down to only needing -40 DEG C,
Have compared with the stationary crystallization that industry uses significantly energy saving.
Preparation method of the invention is simple, using being easy to purchase, is worth lower raw material, improves reaction efficiency, shortens
Production cycle increases substantially the efficiency of crystallization using novel high-efficiency evaporating and crystallizing method, and intermediate reaction object can
It is effectively purified, the micro-moisture in solution is effectively removed, to significantly reduce the moisture in product, trip
From acid, metal, insoluble matter and other impurities, while production cost is reduced greatly.
Preferably, lithium hexafluorophosphate solution is prepared via a method which in step (1): by high-purity PF5Gas is passed through LiF
Anhydrous hydrogen fluoride solution in, the lower reaction of low temperature pressurization.
Preferably, PF5: the molar ratio of LiF:HF is 1:0.4~2.5:20~40, preferably 1:1:20~40, further
Preferably 1:1:25.Preferably, the low temperature is 0~10 DEG C, and preferably 0~5 DEG C, the pressure of pressurization is 0.05~0.2Mpa,
Preferably 0.05~0.1Mpa, the time of reaction are 1~12 hour, preferably 10 hours.Control temperature in reaction, pressure can be with
The effective generation for inhibiting side reaction, greatly improves product yield.
Wherein, high-purity PF5Gas refers to that purity is 99% or more, preferably 99.95% or more PF5Gas.
Preferably, high-purity PF5Gas is prepared via a method which: hydrogen fluoride is added to PCl5In, it pressurizes in heating
Lower reaction generates PF5, HCl gas by efficient gas accurate filter prepare high-purity PF containing HCl5Gas.After reaction
PF5It is about 1:5 with HCl molar ratio, high-purity herein eliminated except PF5, most impurity other than HCl.Preferably, described
The temperature of heating is 50~300 DEG C, and preferably 100~150 DEG C, the pressure of pressurization is 0.05~0.2Mpa, preferably 0.05~
0.1Mpa, the time of reaction are 1~12 hour, preferably 10 hours.
Preferably, removing described in step (2) is carried out by filtering, preferably carried out by millipore filter.
Preferably, the aperture of the millipore filter is 0.1~0.45 μm, preferably 0.1 μm.
Preferably, the solution is sent by nitrogen pressure into crystallizing evaporator.
Preferably, the heating is is warming up to 20~35 DEG C, for example, 22 DEG C, 26 DEG C, 29 DEG C, 33 DEG C etc., and preferably 25
~30 DEG C.It heats up too low, evaporation rate is slow, influences efficiency, and temperature is excessively high, and evaporation rate is too fast, and crystal is quickly precipitated, and leads to crystalline substance
Body wrappage is excessive, purity decline.Therefore, it selects suitable to be warming up to 20~35 DEG C.
Preferably, the hydrogen fluoride evaporated recycles after condensation.The condensation that the condensation can be carried by crystallizer
Device carries out.
Preferably, evaporating liquid level in step (3) to initial liquid level 1/2.
Preferably, temperature gradient is for example, 4 DEG C/h, 6 DEG C/h, 8 DEG C/h etc. by 3-10 DEG C/h of rate of temperature fall, preferably
It is completed for 5 DEG C/h.
Preferably, -30 DEG C are cooled to according to temperature gradient.Crystallization temperature minimum needs to arrive -30 DEG C, uses compared with industry
Stationary crystallization has energy conservation by a larger margin.
Preferably, described to be filtered through the progress of efficient fine filter.
Preferably, the aperture of the efficient fine filter filter is 0.1~0.45 μm, preferably 0.1 μm.
Preferably, the first product of gained lithium hexafluoro phosphate obtains target product lithium hexafluoro phosphate after dry by being granulated.
Preferably, the granulation is granulated by pelletizer.
Preferably, the partial size after the granulation is 40~200 mesh.
Preferably, the drying carries out in nitrogen atmosphere, prevents lithium hexafluoro phosphate from hydrolyzing and generating other by-products.
Preferably, the temperature of the drying is 55~75 DEG C, preferably 60~70 DEG C.Hexafluoro when drying temperature is higher than 80 DEG C
Lithium phosphate starts to decompose, and generates hydrogen fluoride and lithium fluoride.
Preferably, fluorine gas is passed through into filtered liquid, fluorine gas is reacted with the micro-moisture in liquid, produced
Hydrogen fluoride purifies mother liquor, utilizes again.Preferably, preparation method of the invention includes the following steps:
(1) intermediate product PF5Preparation and purification: hydrogen fluoride is added to and has been added into PCl5Reactor in, temperature control
100~150 DEG C or so of system generates PF5, HCl gas, the mixed gas pass through efficient gas accurate filter, that is, prepare height
The mixed gas of the PF5 and HCl of purity;
(2)LiPF6Preparation: above-mentioned steps preparation high-purity PF5Gas is passed through the reaction kettle for adding LiF, hydrogen fluoride
In, temperature control is 0~10 DEG C, and pressure is controlled in 0.05~0.1Mpa, that is, prepares lithium hexafluorophosphate solution;
(3) evaporative crystallization, solid-liquid separation process: by lithium hexafluorophosphate solution by millipore filter filter out it is micro insoluble
Liquid is sent into crystallizing evaporator by nitrogen pressure, starts the temperature of crystallizer rising to 25 DEG C~30 by property impurity, filtrate
DEG C or so, the solvent fluorination hydrogen partial in solution is distilled, the hydrogen fluoride distilled out is carried optionally past crystallizer
Condenser condensation, condensate enter specified raw material storage tank, for use;When stoste position wait crystallize halves, stop evaporation.Then
Crystallizing evaporator is cooled down according to temperature gradient, 5 DEG C/h of rate of temperature fall, when temperature is to -30 DEG C or so, cooling terminates, and six
Lithium fluophosphate crystal is precipitated, and liquid (mother liquor) is filtered the lithium hexafluoro phosphate into spare storage tank again by the method for filtering
It stays in filter, has just obtained the first product of lithium hexafluoro phosphate;
Optionally (4) mother liquor purifies: filtered liquid is stirred, then is passed through fluorine gas into filtered liquid,
Fluorine gas is reacted with the micro-moisture in liquid, produces hydrogen fluoride, is purified to mother liquor, then is added lithium fluoride and returned
To the secondary response again of the reaction kettle in step (2);
(5) purification packaging: lithium hexafluoro phosphate first product enters pelletizer and is granulated, and 40~200 mesh of particle size range, warp is made
Cross after the drying equipment of nitrogen atmosphere environment and obtained the finished product of lithium hexafluoro phosphate, be packed and stored, be granulated, dry, pack it is whole
A process is all passed through nitrogen and is protected, and prevents lithium hexafluoro phosphate from hydrolyzing and generating other by-products.
Preferably, crystallization in entire preparation method, be separated by solid-liquid separation, be granulated, is dry, packaging when be all made of nitrogen and/or
Inert gas shielding.
The present invention prepares lithium hexafluoro phosphate product by the method for simply synthesis, crystallization, mother liquor purifying, product purification,
Using anhydrous hydrogen fluoride, phosphorus pentachloride and lithium fluoride as raw material, fluorine gas, nitrogen as auxiliary material, by 2 step synthetic reactions,
Evaporative crystallization, separation of solid and liquid, granulation, drying, lithium hexafluoro phosphate finished product made from packaging, the mother liquor purifying after Crystallization Separation, then
It recycles.
During present invention process, overall process employs nitrogen as to protect gas, the raw material, reaction after having prevented purification
Just, finished absorbent moisture content leads to the generation of part side reaction and finished product is avoided to decompose because absorbing moisture content, increases impurity.In addition
Using the method for fluorine gas purification mother liquor to greatly reduce mother liquor, the moisture in production process.In phosphorus pentachloride and fluorination
Control temperature, pressure can effectively inhibit the generation of side reaction in first order reaction of hydrogen, greatly improve product yield.
Device therefor of the present invention such as reaction kettle, crystallizing evaporator, the main material of pelletizer etc. can be used as SUS316L,
There is very big cost advantage compared with lining PFA, special alloy equipment, has also prevented under nitrogen atmosphere because the corrosion of equipment is largely golden
Category enters product.
The present invention prepares lithium hexafluoro phosphate using hydrogen fluoride, phosphorus pentachloride, lithium fluoride as raw material, and various raw material sources are abundant,
Raw material is easy to get and inexpensively, and production cost is low, and technical process is simple, and operation controls simple and convenient, high production efficiency, reactivity,
Product yield is high, good product quality.And significantly reduce the moisture in product, free acid, metal impurities content, hexafluoro
Lithium phosphate product purity can reach 99.96% or more, meet the needs of power lithium-ion battery production.The present invention has good
Economic value and social value, be easy promote and apply.
Specific embodiment
Of the invention for ease of understanding, it is as follows that the present invention enumerates embodiment.Those skilled in the art are it will be clearly understood that the implementation
Example is used only for helping to understand the present invention, should not be regarded as a specific limitation of the invention.
Embodiment 1
A kind of preparation method of lithium hexafluoro phosphate, comprising the following steps:
(1) modulation of lithium fluoride solution
It takes anhydrous hydrogen fluoride 1000kg to be added in synthesis reaction vessel, then high-purity fluorination is added by automatic airtight charger
Lithium 50kg, is sufficiently stirred, and temperature controls near -5 DEG C.
(2)PF5Preparation and purifying:
405kg phosphorus pentachloride is added to stainless steel reactor using vacuum blanking machine, by automatic regulating valve to reactor
Middle addition anhydrous hydrogen fluoride 195kg, the control of reaction process temperature at 100~150 DEG C or so, pressure control 0.05~
0.1MPa, it is PF that reaction, which generates product,5, hydrogen chloride, containing a small amount of unreacted hydrogen fluoride in the mixed gas, in a gaseous form
In the presence of;The mixed gas enters accurate gas filter (0.1 μm of filtering accuracy), that is, prepares the PF of high-purity5With hydrogen chloride
Mixed gas.
(3) enter in the reaction kettle for adding LiF after purification and reacted, which can promote with stirring
Into PF5It dissolves, react in the solution, improve reaction efficiency;Reaction temperature controls between 5~10 DEG C, and pressure control exists
Between 0.05~0.1MPa, reaction generates lithium hexafluorophosphate solution.Temperature is stablized at 10 DEG C after reaction.Hydrogen chloride with
And the hydrogen fluoride gas of entrainment is uninterruptedly discharged, by condenser, by hydrogen fluoride and HCl separation, hydrogen fluoride returns head tank and waits for
With by-product salt acid solution is made in hydrogen chloride after water absorbs.
(4) lithium hexafluoro phosphate crystallizes, and is separated by solid-liquid separation
It is made after lithium hexafluorophosphate solution and enters crystallizing evaporator after efficient fine filter (0.1 μm of filtering accuracy)
In crystallized, begin to warm up heating, at 25 DEG C~30 DEG C, the hydrogen fluoride gas being evaporated passes through condenser for temperature control,
It is stand-by to enter head tank after fluorination liquefaction of hydrogen, when liquid level is down to 450~500L and is risen, stops evaporation, using temperature gradient method knot
Crystalline substance, to -30 DEG C, rate of temperature fall control is controlled in 5 DEG C/h, crystallization time in 12h final temperature.Pass through filtering dress after the completion of crystallization
It sets and is separated by solid-liquid separation, liquid enters storage tank, and crystal takes out in nitrogen atmosphere.
(5) lithium hexafluoro phosphate purifies
Enter pelletizer to above-mentioned lithium hexafluoro phosphate first product to be granulated, product is in nitrogen atmosphere environment through 60~70 DEG C
(temperature is higher than 80 DEG C, and lithium hexafluoro phosphate starts to decompose, and generates hydrogen fluoride and lithium fluoride) is dried.Finally obtain hexafluoro phosphorus
Sour lithium first product 219kg.
Obtained product is analyzed, product purity 99.98%, free acid 38ppm, moisture 2.1ppm,
Insoluble matter is 59ppm, iron 0.32ppm.The index of the present embodiment products obtained therefrom is in industry-leading level.
Embodiment 2
A kind of preparation method of lithium hexafluoro phosphate, comprising the following steps:
(1) fluorine gas nitrogen mixing 1kg (F is slowly passed through into the mother liquor after Crystallization Separation2: N2=1:4), it stirs simultaneously,
Process continues 30 minutes, removes the micro-moisture in mother liquor.(F2+H2O=HF+HFO)
(2) whole mother liquor 550kg after removal of impurities are returned into reaction kettle, add 500kg fluorination hydrogen feedstock, then add fluorine
Change lithium 37kg, be sufficiently stirred, temperature controls near -5 DEG C;
(3) 300kg phosphorus pentachloride is added to stainless steel reactor using vacuum blanking machine, by automatic regulating valve to reaction
Anhydrous hydrogen fluoride 150kg is added in device, the control of reaction process temperature at 100~150 DEG C or so, pressure control 0.05~
0.1MPa, it is PF that reaction, which generates product,5, hydrogen chloride, containing a small amount of unreacted hydrogen fluoride in the mixed gas, in a gaseous form
In the presence of;The mixed gas enters accurate gas filter (0.1 μm of filtering accuracy),
(4) enter in the reaction kettle for adding LiF after purification and reacted, which can promote with stirring
Into PF5It dissolves, react in the solution, improve reaction efficiency;Reaction temperature controls between 5~10 DEG C, and pressure control exists
Between 0.05~0.1MPa, reaction generates lithium hexafluorophosphate solution.Temperature is stablized at 10 DEG C after reaction.Hydrogen chloride with
And the hydrogen fluoride gas of entrainment is uninterruptedly discharged, by condenser, by hydrogen fluoride and HCl separation, hydrogen fluoride returns head tank and waits for
With by-product salt acid solution is made in hydrogen chloride after water absorbs;
(5) it is made after lithium hexafluorophosphate solution and enters evaporation knot after efficient fine filter (0.1 μm of filtering accuracy)
It is crystallized in brilliant device, begins to warm up heating, temperature controls the hydrogen fluoride gas being evaporated at 25 DEG C~30 DEG C by condensation
Device, be fluorinated liquefaction of hydrogen after enter head tank it is stand-by, when liquid level be down to 450~500L rise when, stop evaporation, using temperature gradient method
Crystallization, to -30 DEG C, rate of temperature fall control is controlled in 5 DEG C/h, crystallization time in 12h final temperature.Pass through filtering after the completion of crystallization
Device is separated by solid-liquid separation, and liquid enters storage tank, and crystal takes out in nitrogen atmosphere.
(6) enter pelletizer to above-mentioned lithium hexafluoro phosphate first product to be granulated, product in nitrogen atmosphere environment through 60~
70 DEG C are dried (temperature is higher than 80 DEG C, and lithium hexafluoro phosphate starts to decompose, and generates hydrogen fluoride and lithium fluoride).Finally obtain six
Lithium fluophosphate first product 212kg.
Obtained product is analyzed, product purity 99.98%, free acid 32ppm, moisture 1.8ppm,
Insoluble matter is 49ppm, iron 0.45ppm.The index of the present embodiment products obtained therefrom is in industry-leading level.
Embodiment 3
A kind of preparation method of lithium hexafluoro phosphate, comprising the following steps:
(1) modulation of lithium fluoride solution
It takes anhydrous hydrogen fluoride 1000kg to be added in synthesis reaction vessel, then high-purity fluorination is added by automatic airtight charger
Lithium 50kg, is sufficiently stirred, and temperature controls near -5 DEG C.
(2)PF5Preparation and purifying:
405kg phosphorus pentachloride is added to stainless steel reactor using vacuum blanking machine, by automatic regulating valve to reactor
Middle addition anhydrous hydrogen fluoride 195kg, at 150 DEG C or so, pressure control generates the control of reaction process temperature in 0.05MPa, reaction
Product is PF5, hydrogen chloride exists in a gaseous form containing a small amount of unreacted hydrogen fluoride in the mixed gas;The mixed gas
Into accurate gas filter (0.1 μm of filtering accuracy), that is, prepare the PF of high-purity5With the mixed gas of hydrogen chloride.
(3) enter in the reaction kettle for adding LiF after purification and reacted, which can promote with stirring
Into PF5It dissolves, react in the solution, improve reaction efficiency;Reaction temperature controls between 5 DEG C, and pressure is controlled in 0.1MPa
Between, reaction generates lithium hexafluorophosphate solution.Temperature is stablized at 10 DEG C after reaction.The fluorination of hydrogen chloride and entrainment
Hydrogen is uninterruptedly discharged, and by condenser, by hydrogen fluoride and HCl separation, hydrogen fluoride time head tank is stand-by, hydrogen chloride warp
By-product salt acid solution is made after absorbing in water.
(4) lithium hexafluoro phosphate crystallizes, and is separated by solid-liquid separation
It is made after lithium hexafluorophosphate solution and enters crystallizing evaporator after efficient fine filter (0.1 μm of filtering accuracy)
In crystallized, begin to warm up heating, temperature controls the hydrogen fluoride gas being evaporated at 30 DEG C by condenser, hydrogen fluoride
It is stand-by to enter head tank after liquefaction, when liquid level is down to initial liquid level 1/2, stops evaporation, is crystallized using temperature gradient method, finally
To -30 DEG C, rate of temperature fall control is controlled in 3 DEG C/h, crystallization time in 12h temperature.It is carried out after the completion of crystallization by filter device
It is separated by solid-liquid separation, liquid enters storage tank, and crystal takes out in nitrogen atmosphere.
(5) lithium hexafluoro phosphate purifies
Enter pelletizer to above-mentioned lithium hexafluoro phosphate first product to be granulated, product carries out in nitrogen atmosphere environment through 60 DEG C
Dry (temperature is higher than 80 DEG C, and lithium hexafluoro phosphate starts to decompose, and generates hydrogen fluoride and lithium fluoride).Finally obtain lithium hexafluoro phosphate
First product 243kg.
Obtained product is analyzed, product purity 99.97%, free acid 48ppm, moisture 2.6ppm,
Insoluble matter is 60ppm, iron 0.62ppm.The index of the present embodiment products obtained therefrom is in industry-leading level.
Embodiment 4
A kind of preparation method of lithium hexafluoro phosphate, comprising the following steps:
(1) modulation of lithium fluoride solution
It takes anhydrous hydrogen fluoride 1000kg to be added in synthesis reaction vessel, then high-purity fluorination is added by automatic airtight charger
Lithium 50kg, is sufficiently stirred, and temperature controls near -5 DEG C.
(2)PF5Preparation and purifying:
405kg phosphorus pentachloride is added to stainless steel reactor using vacuum blanking machine, by automatic regulating valve to reactor
Middle addition anhydrous hydrogen fluoride 195kg, the control of reaction process temperature is at 100 DEG C or so, and in 0.1MPa, reaction, which generates, to be produced for pressure control
Object is PF5, hydrogen chloride exists in a gaseous form containing a small amount of unreacted hydrogen fluoride in the mixed gas;The mixed gas into
Enter accurate gas filter (0.1 μm of filtering accuracy), that is, prepares the PF of high-purity5With the mixed gas of hydrogen chloride.
(3) enter in the reaction kettle for adding LiF after purification and reacted, which can promote with stirring
Into PF5It dissolves, react in the solution, improve reaction efficiency;Reaction temperature controls between 10 DEG C, and pressure control exists
Between 0.05MPa, reaction generates lithium hexafluorophosphate solution.Temperature is stablized at 10 DEG C after reaction.Hydrogen chloride and folder
The hydrogen fluoride gas of band is uninterruptedly discharged, and by condenser, by hydrogen fluoride and HCl separation, hydrogen fluoride time head tank is stand-by,
By-product salt acid solution is made in hydrogen chloride after water absorbs.
(4) lithium hexafluoro phosphate crystallizes, and is separated by solid-liquid separation
It is made after lithium hexafluorophosphate solution and enters crystallizing evaporator after efficient fine filter (0.1 μm of filtering accuracy)
In crystallized, begin to warm up heating, temperature controls the hydrogen fluoride gas being evaporated at 25 DEG C by condenser, hydrogen fluoride
It is stand-by to enter head tank after liquefaction, when liquid level is down to initial liquid level 2/3, stops evaporation, is crystallized using temperature gradient method, finally
To -30 DEG C, rate of temperature fall control is controlled in 10 DEG C/h, crystallization time in 12h temperature.It is carried out after the completion of crystallization by filter device
It is separated by solid-liquid separation, liquid enters storage tank, and crystal takes out in nitrogen atmosphere.
(5) lithium hexafluoro phosphate purifies
Enter pelletizer to above-mentioned lithium hexafluoro phosphate first product to be granulated, product carries out in nitrogen atmosphere environment through 70 DEG C
Dry (temperature is higher than 80 DEG C, and lithium hexafluoro phosphate starts to decompose, and generates hydrogen fluoride and lithium fluoride).Finally obtain lithium hexafluoro phosphate
First product 198kg.
Obtained product is analyzed, product purity 99.98%, free acid 44ppm, moisture 2.3ppm,
Insoluble matter is 54ppm, iron 0.28ppm.The index of the present embodiment products obtained therefrom is in industry-leading level.
Obviously, the above embodiments are merely examples for clarifying the description, and does not limit the embodiments.It is right
For those of ordinary skill in the art, can also make on the basis of the above description it is other it is various forms of variation or
It changes.There is no necessity and possibility to exhaust all the enbodiments.And it is extended from this it is obvious variation or
It changes still within the protection scope of the invention.