JP2013229326A - Method for processing electrolyte containing fluorine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for safely processing an electrolyte containing a volatile fluorine compound (LiPF, or the like) and an organic solvent.SOLUTION: The method for processing an electrolyte containing a fluorine compound includes a vaporization step for vaporizing the volatile components of an electrolyte containing a fluorine compound by heating it under reduced pressure, a fluorine fixing step for fixing the fluorine component contained in the vaporized gas as calcium fluoride by causing reaction with calcium, and an organic solvent component recovery step for recovering the organic solvent component contained in the vaporized gas. Preferably, volatile components of electrolyte are vaporized by heating the electrolyte under reduced pressure after adding a small quantity of water thereto.

Description

The present invention relates to a safe treatment method for non-aqueous electrolytes used in lithium ion batteries and the like.

Many large-sized lithium ion batteries are used in electric vehicles and electronic devices to supply high-capacity electricity, and the treatment of large-sized used batteries that are generated in large quantities due to the widespread use of electric vehicles and electronic devices is becoming a problem. is there.

Electrolytic solutions used in lithium ion batteries and the like contain fluorine compounds (LiPF ₆ , LiBF _4, etc.) that serve as electrolytes and volatile organic solvents, which are mainly carbonates. It is a flammable substance. Moreover, when LiPF ₆ reacts with water, it hydrolyzes to generate toxic hydrogen fluoride. For this reason, a safe processing method is required.

Conventionally, the following treatment methods are known as a treatment method for a lithium ion battery and its electrolytic solution.
1. A processing method in which a lithium ion battery or the like is frozen below the melting point of the electrolytic solution, the battery is disassembled and crushed, the electrolytic solution is separated from the crushed material in an organic solvent, and the extracted electrolytic solution is distilled to separate the electrolyte into an organic solvent (Patent Document 1).
2. A processing method for roasting a used lithium battery, crushing the roasted product, separating it into a magnetic material and a non-magnetic material, and recovering a large amount of useful metals such as aluminum and copper (Patent Document 2).
3. A treatment method in which a lithium battery is opened with ultra-high pressure water and an electrolytic solution is recovered using an organic solvent (Patent Document 3).

Japanese Patent No. 3935594 Japanese Patent No. 3079285 Japanese Patent No. 2721467

In the conventional processing method, the processing method of dismantling and crushing the lithium battery under refrigeration requires refrigeration equipment and is difficult to implement. Further, in the method of roasting a lithium battery, fluorine is treated as a combustion gas, so that it cannot be recovered as a highly pure fluorine component and cannot be reused. In the processing method of recovering the electrolytic solution using an organic solvent, the processing of the recovered electrolytic solution becomes a problem. As pointed out earlier, the electrolyte contains a flammable organic solvent, and the fluorine compound in the electrolyte reacts with water to generate toxic hydrogen fluoride. It is done.

The present invention has solved the above problems in the conventional processing method, a method for safely processing the electrolyte containing volatile fluorine compound (LiPF ₆ or the like) and an organic solvent.

This invention provides the processing method of the fluorine-containing electrolyte solution which consists of the following structures.
[1] A vaporization step of heating and vaporizing a volatile component of an electrolytic solution containing a fluorine compound, a fluorine fixation step of reacting the fluorine component contained in the vaporized gas with calcium to fix it as calcium fluoride, a vaporized gas The processing method of the fluorine-containing electrolyte solution characterized by having the organic-solvent collection process which collect | recovers the organic-solvent component contained in this.
[2] The method for treating a fluorine-containing electrolytic solution according to the above [1], wherein in the vaporizing step, a small amount of water or dilute mineral acid is added to the electrolytic solution and then heated under reduced pressure to vaporize a volatile component of the electrolytic solution. .
[3] The gas in which the volatile component of the electrolytic solution is vaporized is guided to a wet treatment process, and in the wet treatment process, the fluorine component and the organic solvent component contained in the gas are collected in water, and the collected liquid is separated into oil and water. Fluorine-containing as described in [1] or [2] above, wherein the organic solvent component is recovered while a calcium compound is added to the separated aqueous phase to react fluorine and calcium in the aqueous phase to produce calcium fluoride Electrolyte treatment method.
[4] The gas in which the volatile component of the electrolytic solution is vaporized is introduced into a wet treatment step, and in the wet treatment step, the fluorine component and the organic solvent component contained in the gas are condensed and collected, and the calcium compound is collected in the collected solution. The method for treating a fluorine-containing electrolytic solution according to the above [1] or [2], wherein the fluorine is reacted with calcium to produce calcium fluoride.
[5] The gas in which the volatile component of the electrolyte is vaporized is introduced into a wet treatment process, and in the wet treatment process, fluorine in the gas is absorbed into the mixed liquid by contacting with the calcium compound mixed liquid and reacts with fluorine and calcium. The method for treating a fluorine-containing electrolytic solution according to any one of [1] or [2] above, wherein calcium fluoride is produced and the gas that has passed through the mixed solution is condensed to recover the organic solvent component.
[6] The gas in which the volatile component of the electrolytic solution is vaporized is introduced into a dry treatment process, and in the dry treatment process, the vaporized gas is passed through a packed bed of calcium compounds to react fluorine and calcium in the gas to produce calcium fluoride. The method for treating a fluorine-containing electrolytic solution according to any one of the above [1] or [2], wherein the organic solvent component is recovered by condensing the gas that has been generated and further passed through the packed bed.
[7] Under the reduced pressure of 5 kPa to normal pressure, heat to 80 to 150 ° C. to vaporize the volatile components of the electrolytic solution, and lead the vaporized gas to the wet processing step or the dry processing step. [6] The method for treating a fluorine-containing electrolytic solution according to any one of [6].
[8] The method for treating a fluorine-containing electrolytic solution according to the above [1], wherein the volatile component of the electrolytic solution is vaporized by heating to 80 to 150 ° C. under a reduced pressure of 1 kPa or less, and the vaporized gas is led to the dry treatment step.
[9] Treatment of the fluorine-containing electrolyte solution according to any one of [1] to [8] above, wherein calcium fluoride is recovered and recycled, and the recovered organic solvent component is used as a fuel or an alternative fuel. Method.
[10] A pipe line is connected to an opening of a used battery containing an electrolytic solution containing a fluorine compound, and the used battery is heated under reduced pressure to vaporize a volatile component of the electrolytic solution. The method for treating a fluorine-containing electrolytic solution according to any one of the above [1] to [9], wherein the treatment is conducted through a conduit to a fluorine fixing step and an organic solvent recovery step.
[11] A safety valve of a used lithium ion battery is opened, a pipe line is connected to the opening, and the volatile component of the electrolytic solution is vaporized by heating under reduced pressure. The processing method of the fluorine-containing electrolyte solution to describe.
[12] Open a safety valve of a plurality of used lithium ion batteries, store these batteries in a sealed container, connect a conduit to the container, and heat under reduced pressure to vaporize the volatile components of the electrolyte. The method for treating a fluorine-containing electrolyte solution according to any one of [1] to [10] above.

[Specific description]
Hereinafter, the present invention will be specifically described. In addition,% is the mass%.
The treatment method of the present invention is a vaporization step in which a volatile component of an electrolyte solution containing a fluorine compound is heated and vaporized under reduced pressure, and a fluorine fixation in which the fluorine component contained in the vaporized gas is reacted with calcium and fixed as calcium fluoride. A process for treating a fluorine-containing electrolytic solution, comprising: an organic solvent recovery step of recovering an organic solvent component contained in the step and vaporized gas.

Electrolytic solutions used in lithium ion batteries and the like contain an electrolyte fluorine compound and an organic solvent. The fluorine compound is mainly lithium hexafluorophosphate (LiPF ₆ ), and the organic solvent is dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), dimethyl carbonate (DEC), propylene carbonate (PC), ethylene carbonate (EC). Such as carbonate esters. Of these, DMC is a flammable substance classified as Fire Class 4 Class 1 Petroleum, and EMC and DEC are Class 4 Class 2 Petroleum Law.

Therefore, in order to safely remove the electrolyte from the lithium ion battery, the treatment method of the present invention discharges the used lithium ion battery, peels off the packaging sheet, and vaporizes the electrolyte under reduced pressure using a safety valve. A lithium ion battery is provided with a safety valve in order to reduce the excessive internal pressure of the battery. The safety valve is opened, and a pipe 12 is connected to the opening 11 as shown in FIG. 1, the battery is heated under reduced pressure to vaporize volatile components of the electrolyte, and the generated gas is treated through the pipe 12. Guide to the process.

[Vaporization process]
Among the organic solvents contained in the electrolytic solution, the boiling point of DMC is 90 ° C, the boiling point of EMC is 109 ° C, the boiling point of DEC is 127 ° C, the boiling point of PC is 240 ° C, and the boiling point of EC is 244 ° C. The liquid is heated to a temperature higher than these boiling points to vaporize the volatile components (DMC, EMC, DEC, PC, EC, etc.). LiPF ₆ decomposes lithium hexafluorophosphate by heating or hydrolysis, and vaporizes the fluorine component.

Specifically, 0 ° C., 10 ° C., 20 ° C., 80 ° C., and 150 ° C. at atmospheric pressure (101.3 kPa) are shown in Table 1 under reduced pressures of 15 kPa, 10 kPa, 5 kPa, 1 kPa, and 0.1 kPa. Since it is in the atmospheric pressure conversion temperature state, DMC, EMC, DEC, PC, EC, etc. can be volatilized by heating so that the conversion temperature of the electrolyte is 244 ° C. or higher under the selected reduced pressure. .

For example, if the inside of the battery is depressurized to 5 kPa and heated to 80 ° C. to 150 ° C., the electrolyte becomes 170 ° C. to 251 ° C. Therefore, DMC, EMC, DEC, PC, EC, heat contained in the electrolyte The decomposed fluorine compound can be volatilized. The pressure may be lower than 5 kPa, for example, reduced to 1 kPa to 0.1 kPa and heated to 80 ° C. to 120 ° C.

By adding a small amount of water to the electrolytic solution and heating it under reduced pressure to vaporize the volatile components of the electrolytic solution, LiPF ₆ reacts sequentially with water to give phosphoric acid and fluoride as shown in the following formula. because hydrolyzed to hydrogen, can be accelerated vaporization by decomposition of LiPF _6.

LiPF ₆ + H ₂ O → LiF + 2HF (↑) + POF ₃
POF ₃ + H ₂ O → HPO ₂ F ₂ + HF (↑)
HPO ₂ F ₂ + H ₂ O → H ₂ PO ₃ F + HF (↑)
H ₂ PO ₃ F + H ₂ O → H ₃ PO ₄ + HF (↑)

According to the method of vaporizing by adding water, a large amount of fluorine can be vaporized as HF. Further, as shown in the above formula, fluorine vaporizes as HF, but phosphorus remains as a solution as H ₃ PO ₄ , so that the effect of separating fluorine and phosphorus is good. The amount of water added is desirably 5% to 20% with respect to the weight of the electrolyte. The form of water to be added may be either liquid or gas (water vapor). The method of adding water may be a method of adding in advance, a method of adding sequentially during the reaction, a method of supplying continuously, or a method combining these.

The decomposition of LiPF ₆ can be similarly promoted by adding a small amount of dilute mineral acid to the electrolytic solution. As the mineral acid, sulfuric acid, hydrochloric acid, nitric acid and the like can be used. The concentration of the mineral acid is suitably 0.1M to 5M, and the addition amount is desirably 5% to 20% with respect to the weight of the electrolyte. If the concentration is higher than this, sulfuric acid, hydrochloric acid, and nitric acid are also volatilized and recovered at the same time when distilled under reduced pressure, and therefore, when fluorine is recovered as calcium fluoride, the purity is lowered.

The vaporized volatile component gas is introduced into a wet treatment process or a dry treatment process to fix fluorine as calcium fluoride, and an organic solvent (oil phase) is recovered.

[Wet treatment]
An example of wet processing (water-cooled collection) is shown in FIG. As shown in the figure, the battery 10 is housed in a heating facility 15, and a conduit 12 extending from the opening 11 of the battery 10 is connected to a vacuum pump 13 via a cooler 16 and a water-cooled trap 14. In the illustrated example, a two-stage water-cooled trap is provided. The water-cooled trap is filled with water and is kept at 0 ° C to 10 ° C. The battery 10 is heated by the heating equipment 15 and further the electrolyte solution is vaporized in a state where the pressure is reduced by the vacuum pump 13, and this vaporized gas is sucked into the vacuum pump 13 and led to the cooler 16 through the conduit 12. It is cooled here to become a condensate, and further led to the water-cooled trap 14. At this time, the decompression condition in the pipe may be maintained at a constant pressure, or may be changed such that the pressure is decreased at a constant speed, or atmospheric pressure and decompression are alternately repeated at regular time intervals. The degree of decompression can be easily adjusted by controlling the operation of the vacuum pump. The water-cooled trap 14 collects the fluorine compound (HF or the like) and the organic solvent component (organic components: DMC, EMC, DEC, PC, EC, etc.) in a water-cooled manner.

Thus, the water-cooled trap 14 collects the organic solvent and hydrogen fluoride, which are separated into an aqueous phase and an organic phase. The separated aqueous phase is recovered. This aqueous phase contains a fluorine component in the vaporized gas. The water-cooled trap 14 may be installed in a plurality of stages in series or in parallel or a combination of both.

The aqueous phase (fluorine-containing water) is acidic water having a pH of 2 or less. Calcium compounds (calcium carbonate, slaked lime, quicklime, etc.) are added to the fluorine-containing water to neutralize to pH 5.5 to 7.0, and the fluoride and calcium in the liquid are reacted to precipitate calcium fluoride. The calcium fluoride is recovered by solid-liquid separation.

[Wet treatment]
Another example (condensation collection) of the wet processing step is shown in FIG. As shown in the figure, the battery 10 is housed in a heating facility 15, and a conduit 12 extending from the opening 11 of the battery 10 is connected to a vacuum pump 13 through a cooler 16 and a trap 14. The battery 10 is heated by the heating equipment 15 and further the electrolyte solution is vaporized in a state where the pressure is reduced by the vacuum pump 13. It is cooled here to become a condensate, and this condensate is guided to the trap 14. The trap 14 collects a fluorine compound (HF, etc.) and an organic solvent component (organic component: DMC, EMC, DEC, PC, EC, etc.).

The liquid recovered by the trap 14 is mainly composed of organic solvent components. When water or dilute sulfuric acid is added first, it also contains water, but this organic solvent component is highly soluble in water, and a small amount of water dissolves, so the liquid phase is not separated and only the organic phase. . The liquid collected by the trap 14 is fluorine-containing water having a pH of 2 or less. A calcium compound (slaked lime, quicklime, etc.) is added to the fluorine-containing water to neutralize the pH to 5.5 to 7.0, and the fluoride and calcium in the liquid are reacted to precipitate calcium fluoride. This is subjected to solid-liquid separation to recover a liquid organic solvent and solid calcium fluoride.

Another example of wet processing (calcium absorption collection) is shown in FIG. As shown in the figure, the battery 10 is housed in a heating facility 15, and a pipe line 12 extending from the opening 11 of the battery 10 is connected to a vacuum pump 13 via a Ca mixture container 17, a cooler 16 and a trap 14. Has been. The battery 10 is heated by the heating equipment 15 and further the electrolyte solution is vaporized in a state where the pressure is reduced by the vacuum pump 13, and this vaporized gas is sucked into the vacuum pump 13 and passed through the pipe 12 to the Ca mixed solution container 17. Here, the fluorine component is absorbed into the Ca mixed solution, reacts with the calcium compound, and is fixed to calcium fluoride. The vaporized gas that has passed through the container 17 is led to the cooler 16, cooled to become a condensed liquid, and led to the trap 14. The trap 14 collects organic solvent components (organic components: DMC, EMC, DEC, PC, EC, etc.).

Thus, in the Ca mixed solution container 17, the fluorine component reacts with the calcium compound to generate calcium fluoride. Calcium carbonate, calcium hydroxide, calcium oxide, calcium sulfate, calcium chloride, and calcium nitrate can be used as the calcium compound in the Ca mixed solution, but calcium carbonate capable of granulating calcium fluoride to be recovered at low cost is desirable. . As the liquid of the Ca mixed solution, water or an organic solvent can be used. When the liquid is an organic solvent, an electrolyte component (DMC, EMC, DEC, PC, EC, etc.) may be used. When the organic solvent of the electrolytic solution is used, a part of the vaporized gas may be cooled and condensed and collected in the Ca mixed solution container 17.

When the liquid temperature of Ca liquid mixture falls, the vaporized organic solvent will condense in large quantities, and liquid amount will increase. In order to stabilize the amount of the Ca mixed solution, it is desirable to adjust the amount of the liquid by keeping it warm or vaporizing it. The Ca mixed solution container 17 may be installed in a plurality of stages in series or in parallel, or in combination of series and parallel.

The calcium fluoride produced in the Ca mixed solution container 17 can be recovered by volatilizing the liquid and drying the solid or by separating the suspension into solid and liquid. The liquid from which the fluorine has been removed can be replenished with a new calcium compound and used again as a Ca mixture.

The trap 14 collects the organic solvent. The liquid recovered by the trap 14 is mainly composed of organic solvent components. When water or dilute sulfuric acid is added first, it also contains water, but this organic solvent component is highly soluble in water and can dissolve a small amount of water, so the liquid phase does not separate and the organic phase Only.

(Dry processing)
The dry treatment process is shown in FIG. As shown in the figure, vaporized gas is passed through a packed bed of calcium compounds to react fluorine in the gas with calcium to produce calcium fluoride. This calcium fluoride is extracted from the packed bed and used by replenishing the packed bed with a new calcium compound. On the other hand, the gas that has passed through the packed bed is led to a condensation trap to recover the organic solvent component. The packed bed of calcium compounds may be provided in a plurality of stages in series or in parallel or a combination of both.

In the dry processing coagulation trap, water is not necessary, and the collected gas is condensed and becomes only an organic solvent phase, so that it can be used as a fuel or a combustion aid for combustion equipment. Also, the dry process is easy to operate and does not require waste water treatment.

In the vaporization step, when vaporization is performed at a pressure higher than the vapor pressure of water, the vaporized gas can be led to a wet treatment step or a dry treatment step for treatment. On the other hand, when vaporized at a pressure lower than the vapor pressure of water, water-cooled collection is not suitable, and the vaporized gas is introduced into the dry treatment process for treatment.

Cooling by the cooler 16 is performed until the pressure is reduced to about 5 kPa, and when the vaporized gas is heated and vaporized in a decompression state stronger than this, for example, 1 kPa and 0.1 kPa, the cooler 16 is 10%. A water-cooled trap is not suitable because it is lower than the vapor pressure of water even when cooled to ° C. In this case, the vaporized gas is introduced into the dry treatment process.

On the other hand, when heated and vaporized in a reduced pressure state of 5 kPa to normal pressure, if cooled to 10 ° C. or lower by the cooler 16, the vapor pressure is higher than the vapor pressure of water. be able to. In addition, you may introduce | transduce into a dry process.

According to the treatment method of the present invention, fluorine is recovered from the electrolytic solution as high-purity calcium fluoride, so that it can be recycled as a raw material for producing hydrofluoric acid or a raw material for cement. According to the treatment method of the present invention, calcium fluoride having a purity of 80% or more can be obtained.

Furthermore, according to the treatment method of the present invention, the organic solvent of the electrolytic solution can be recovered and used as fuel or alternative fuel. Since the organic solvent component recovered by the treatment method of the present invention is separated from fluorine, no harmful substances such as hydrogen fluoride are generated when used as a fuel and can be used safely.

Further, according to the treatment method of the present invention, since the electrolyte is vaporized and taken out from the battery, the battery can be made harmless without being frozen or burned at a high temperature, so that material recycling in the subsequent stage is performed safely and efficiently. be able to.

The conceptual diagram which shows a wet process (water-cooled collection). The conceptual diagram which shows a wet process (condensation collection). The conceptual diagram which shows a wet process (calcium absorption collection). The conceptual diagram which shows a dry process.

Examples of the present invention are shown below. In addition, the component of the organic phase liquid was analyzed with a gas chromatograph mass spectrometer. The pH of the liquid was analyzed by the glass electrode method. The fluorine concentration was analyzed by the fluoride ion electrode method. The electrolyte solutions of Examples 2 to 5 are (1 mol / L, LiPF ₆ [EC / DMC / MEC / DEC = 30/30/30/30/10 = (v / v / v / v)]).

[Example 1: Water-cooled collection]
A large battery cell (lithium ion battery, 1.66 kg) for automobiles is discharged, the packaging sheet is peeled off, the safety valve is opened, 18 g of water is added, a pipe line is connected to the opening of the safety valve, and the pressure is reduced to 5 kPa by a vacuum pump. The pressure was reduced, and the mixture was heated by being immersed in an oil heater at 150 ° C. for 2 hours. The generated gas was collected in the order of a cooling pipe (4 ° C.) and a water-cooled trap (liquid amount: 300 mL). This was left at room temperature to separate into an aqueous phase and an organic phase. The separated aqueous phase (340 mL) and the organic phase (120 mL) were recovered. The fluorine concentration of this aqueous phase was 10 g / L and pH2. To this, 6.0 g of slaked lime was added to form a precipitate. The recovered precipitate was analyzed by powder X-ray diffraction and confirmed to be calcium fluoride. The recovered amount of calcium fluoride was 6.3 g and the purity was 80%. On the other hand, when the separated organic phase was recovered and the components were analyzed, the components of the solution were DMC, MEC, DEC, and EC.

[Example 2: Water-cooled collection]
21.5 g of a 1.5 mol / L sulfuric acid aqueous solution was added to 100 mL of the electrolytic solution, a pipe line was connected, the pressure was reduced to 5 kPa with a vacuum pump, and the mixture was immersed in an oil heater for 2 hours and heated. The generated gas was collected in the order of a cooling pipe (4 ° C.) and a water-cooled trap (liquid amount: 200 mL). This was allowed to stand at room temperature to separate into an aqueous phase and an organic phase, and 230 mL of the aqueous phase and 35 mL of the organic phase were recovered. This aqueous phase had a fluorine concentration of 43 g / L and a pH of 2. The aqueous phase was recovered and 18 g of slaked lime was added to form a precipitate. The recovered precipitate was analyzed by powder X-ray diffraction and confirmed to be calcium fluoride. The recovered amount of calcium fluoride was 20 g and the purity was 92%, and it was found that it could be used as a raw material for producing hydrofluoric acid. On the other hand, when the separated organic phase was recovered and the components were analyzed, the components of the solution were DMC, MEC, DEC, and EC.

[Example 3: Aggregation collection]
21.5 g of water was added to 100 mL of the electrolytic solution, a pipe line was connected, the pressure was reduced to 5 kPa with a vacuum pump, and the mixture was immersed in an oil heater at 120 ° C. for 2 hours and heated. The generated gas was condensed by a cooling pipe (4 ° C.) and collected in a collection bottle. The recovered liquid was 95 mL, and only the organic phase was recovered. The fluorine concentration of the recovered liquid was 87 g / L and pH2. To this, 15 g of slaked lime was added to form a precipitate. The recovered precipitate was analyzed by powder X-ray diffraction and confirmed to be calcium fluoride. The recovered amount of calcium fluoride was 14 g, the purity was 93%, and it could be used as a raw material for producing hydrofluoric acid. When the organic phase was analyzed, the components of the solution were DMC, MEC, DEC, and EC.

[Example 4: Aggregation collection]
21.5 g of water was added to 100 mL of the electrolytic solution, a pipe line was connected, and it was immersed in an oil heater at 120 ° C. Reduce the pressure to 20 kPa with a vacuum pump and hold it for 10 minutes. After that, stop the vacuum pump and return the inside of the tube to atmospheric pressure. Then, operate the vacuum pump again to reduce the pressure to 20 kPa. The operation of stopping and returning to atmospheric pressure was repeated for 2 hours. The generated gas was condensed by a cooling pipe (4 ° C.) and collected in a collection bottle. The recovered liquid was 101 mL, and only the organic phase was recovered. The recovered solution had a fluorine concentration of 93 g / L and a pH of 1.9. To this, 17 g of slaked lime was added to form a precipitate. The recovered precipitate was analyzed by powder X-ray diffraction and confirmed to be calcium fluoride. The recovered amount of calcium fluoride was 19 g and the purity was 88%, which could be used as a raw material for producing hydrofluoric acid. When the organic phase was analyzed, the components of the solution were DMC, MEC, DEC, and EC.

[Example 5: Ca absorption collection]
21.5 g of water was added to 100 mL of the electrolytic solution, a pipe line was connected, the pressure was reduced to 15 kPa by a vacuum pump, and the mixture was immersed in an oil heater for 2 hours and heated. The generated gas was passed through a calcium suspension (calcium carbonate 30 g, water 100 mL, adjusted at 30 ° C. to 60 ° C.), absorbed vaporized fluorine, and fixed as calcium fluoride. The organic solvent and the like were condensed by a subsequent cooler (4 ° C.) and collected in a collection bottle. The precipitate recovered in the calcium suspension was analyzed by powder X-ray diffraction and confirmed to be a mixture of calcium fluoride and calcium carbonate. The recovered liquid condensed by the cooler was 80 mL, and only the organic phase. The recovered solution had a fluorine concentration of 5 mg / L and a pH of 6.2, and contained almost no fluorine. When the organic phase was analyzed, the components of the solution were DMC, MEC, DEC, and EC.

[Example 6: Dry treatment]
A large battery cell (lithium ion battery, 1.66 kg) for automobiles is discharged, the packaging sheet is peeled off, a safety valve is opened, 18 g of water is added, a pipe is connected, and the pressure is reduced to 5 kPa by a vacuum pump. It was immersed in an oil heater at 2 ° C. for 2 hours and heated. The generated gas was introduced into the packed bed of calcium carbonate.
After passing through the gas, the packed layer of calcium carbonate was taken out and the components were analyzed by powder X-ray diffraction. As a result, they were unreacted calcium carbonate and calcium fluoride. On the other hand, the gas that passed through the packed bed was led to a condensation trap (0 ° C.) and stored. When the components of the condensate were analyzed, the components of the recovered liquid were DMC, MEC, DEC, and EC, and the fluorine concentration was 30 mg / L.

10-battery, 11-opening, 12-line, 13-vacuum pump, 14-water cooling trap, 15-heating equipment, 16-cooler, 17-Ca mixed liquid container

Claims (12)

Vaporization process for heating and vaporizing volatile components of electrolyte containing fluorine compounds under reduced pressure, fluorine fixing process for reacting calcium components in vaporized gas with calcium to fix them as calcium fluoride, included in vaporized gas A method for treating a fluorine-containing electrolytic solution comprising an organic solvent component recovery step of recovering an organic solvent component. The method for treating a fluorine-containing electrolytic solution according to claim 1, wherein, in the vaporizing step, a small amount of water or dilute mineral acid is added to the electrolytic solution and then heated under reduced pressure to vaporize a volatile component of the electrolytic solution. The gas in which the volatile component of the electrolyte is vaporized is guided to a wet treatment process, in which the fluorine component and the organic solvent component contained in the gas are collected by water cooling, and the collected liquid is separated into oil and water, and the organic solvent component The method for treating a fluorine-containing electrolytic solution according to claim 1 or 2, wherein a calcium compound is added to the separated aqueous phase to react calcium and calcium in the aqueous phase to produce calcium fluoride. . The gas in which the volatile component of the electrolyte is vaporized is introduced into a wet treatment process, where the fluorine component and the organic solvent component contained in the gas are condensed and collected, and a calcium compound is added to the collected liquid. The method for treating a fluorine-containing electrolytic solution according to claim 1 or 2, wherein calcium fluoride is produced by reacting fluorine and calcium. The gas in which the volatile components of the electrolyte are vaporized is introduced into a wet treatment process, and in the wet treatment process, fluorine in the gas is absorbed into the mixed liquid by contacting with the calcium compound mixed liquid, and fluorine and calcium are reacted to form a fluorine. The processing method of the fluorine-containing electrolyte solution in any one of Claim 1 or Claim 2 which produces | generates calcium fluoride and also condenses the gas which passed this liquid mixture, and collect | recovers organic solvent components. The gas in which the volatile component of the electrolyte is vaporized is led to a dry treatment process, and in the dry treatment process, the vaporized gas is passed through a packed bed of calcium compounds to react fluorine and calcium in the gas to generate calcium fluoride, The method for treating a fluorine-containing electrolyte according to claim 1, further comprising condensing the gas that has passed through the packed bed to recover the organic solvent component. Any one of claims 3 to 6, which is heated to 80 to 150 ° C under a reduced pressure of 5 kPa to normal pressure to vaporize a volatile component of the electrolytic solution and guide the vaporized gas to the wet processing step or the dry processing step. The processing method of the fluorine-containing electrolyte solution described in 2. The processing method of the fluorine-containing electrolyte solution of Claim 6 which heats to 80-150 degreeC under reduced pressure of 1 kPa or less, vaporizes the volatile component of electrolyte solution, and guides the vaporized gas to the said dry-type process process. The method for treating a fluorine-containing electrolyte solution according to any one of claims 1 to 8, wherein calcium fluoride is recovered and recycled, and the recovered organic solvent component is used as a fuel or an alternative fuel. Connect a pipe line to the opening of a used battery containing an electrolyte containing a fluorine compound, heat the used battery under reduced pressure to vaporize the volatile components of the electrolyte, and pass the vaporized gas through the pipe. The processing method of the fluorine-containing electrolyte solution in any one of Claims 1-9 which guide and process to a fluorine fixation process and an organic-solvent collection process. The fluorine-containing electrolysis according to any one of claims 1 to 10, wherein a safety valve of a used lithium ion battery is opened, a pipe line is connected to the opening, and the volatile component of the electrolyte is vaporized by heating under reduced pressure. Liquid processing method. A safety valve for a plurality of used lithium ion batteries is opened, these batteries are housed in a sealed container, a pipe line is connected to the container, and the volatile components of the electrolyte are vaporized by heating under reduced pressure. The processing method of the fluorine-containing electrolyte solution in any one of Claims 10.

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