JP3722998B2 - Battery disposal method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating a battery containing a salt comprising a cation and a Lewis acid ion as an electrolyte in the battery, and more particularly, a safe method for treating a lithium ion battery containing lithium hexafluorophosphate as an electrolyte in the battery. About.
[0002]
[Prior art]
With the refraining from adding new thermal power generation due to the recent global warming trend, the effective use of electric power has been screamed, and as a one-off, the surplus power at night is temporarily stored and released in the daytime. Encouragement is also possible, and the emergence of a secondary battery for power storage that can cope with this is expected, and from the standpoint of preventing air pollution, the early practical application of a large secondary battery as a power source for automobiles is expected. The demand for small secondary batteries is also increasing year by year as the power supply for backup of computers, word processors and the like, the power supply for small household electrical appliances, especially portable electric appliances, increase in performance. In response to the growing demand for batteries, there has been a strong demand for effective use of chemical substances used in batteries and establishment of environmental pollution countermeasures using batteries.
[0003]
These secondary batteries are required to be high-performance secondary batteries in proportion to the performance of the equipment used. Mainly, lithium ion introduced into the intercalation compound is used as the positive electrode active material, and graphite is used as the negative electrode active material. Lithium ion batteries using lithium are put into practical use, but electrolytes containing toxic substances are also used in the above-mentioned lithium ion batteries.
[0004]
[Problems to be solved by the invention]
That is, as the electrolyte of the lithium ion battery, for example, ethylene carbonate, diethylene carbonate, dimethyl carbonate, diethyl ether or the like alone or two or more mixed solvents, for example, a fluorine compound such as lithium hexafluorophosphate LiPF ₆ is used alone. An organic electrolyte in which two or more kinds are dissolved is used, and the fluorine compound such as lithium hexafluorophosphate in the electrolyte reacts with moisture in the air to poison toxic gases such as phosphorus pentafluoride and hydrogen fluoride. May occur. As another fluorine compound, arsenic hexafluorophosphate may generate toxic gases such as arsenic fluoride and hydrogen fluoride. This reaction also occurs in other nonaqueous solvent-based discharge batteries, and similarly, there is a risk of generating toxic gases such as phosphorus pentafluoride, arsenic pentafluoride, and hydrogen fluoride.
[0005]
In view of such technical problems, the present invention provides a safe and efficient disassembly treatment method for a battery containing a salt composed of a cation and a Lewis acid ion, in particular, a lithium ion battery. An object of the present invention is to provide a safe treatment method for the lithium ion battery while preventing generation of toxic gases of fluorine compounds such as lithium hexafluorophosphate.
[0006]
[Means for Solving the Problems]
First, the invention described in claim 1 will be described.
The main object of the present invention is a method for treating a lithium ion battery containing lithium hexafluorophosphate as an electrolyte. In addition to this, a salt composed of a cation and a Lewis acid ion is added to the electrolyte in the battery. The batteries that are included are also applicable.
That is, examples of the cation serving as the electrolyte salt include sodium ion, potassium ion, and tetraalkylammonia ion in addition to lithium ion (Li ⁺ ), and BF _{4 as the} Lewis acid ion serving as the electrolyte salt. ^{_{-, PF 6 -, AsF 6}} -, ClO 6 - and the like.
And the salt which consists of these cations and Lewis acid ions is used as an electrolyte after sufficient dehydration and deoxygenation by heating under reduced pressure.
[0007]
And as a means to take out the said salt from other battery crushed materials, since this invention uses heating means, such as water washing, thermal decomposition, or roasting, it makes another claim for each means.
[0008]
That is, the invention according to claim 1 specifies salt separation means by washing with water.
The battery crushed material containing the salt is washed with water to separate the salt into an aqueous solution,
Adding a heated acid aqueous solution to the salt-containing aqueous solution to promote the decomposition of the Lewis acid ion, and adding a fixative such as slaked lime to the ion aqueous solution to fix the Lewis acid ion decomposition product Features.
[0009]
Further, the invention according to claim 2 specifies the salt separation means by heating.
Heating the battery crushed material containing the salt by means of pyrolysis or roasting, and including the salt in exhaust gas;
An exhaust gas treatment process for performing an exhaust gas treatment by bringing a fixing agent aqueous solution such as slaked lime into contact with the exhaust gas;
A heated acid aqueous solution is added to the aqueous solution capturing the salt in the exhaust gas treatment step to promote decomposition of the Lewis acid ion, and a fixative such as slaked lime is added to the aqueous ion solution to produce a Lewis acid ion decomposition product. and the step of fixing the,
It is characterized by including.
[0010]
The invention according to claim 3 is a treatment method of a lithium ion battery containing lithium hexafluorophosphate as an electrolyte in the battery.
A heated acid aqueous solution is added to the lithium hexafluorophosphate-containing aqueous solution in which the battery crushed material containing lithium hexafluorophosphate is separated into water by a predetermined sorting step such as “heating means + exhaust gas treatment” or water washing. After adding and decomposing | disassembling into fluoride ion and phosphate ion, the process of adding fixing agents, such as slaked lime, to the said ion aqueous solution is included, It is characterized by the above-mentioned.
[0011]
According to a fourth aspect of the present invention, the heated acid aqueous solution according to the first, second or third aspect is an acid aqueous solution of HCl, H ₂ SO ₄ , HNO ₃ , HClO ₄ , and the heating temperature is 65 ° C. It is -100 degreeC, It is characterized by the above-mentioned.
[0012]
The present invention will be described below.
The lithium hexafluorophosphate aqueous solution is stable as an aqueous solution after being separated in water by the above-mentioned “heating means + exhaust gas treatment” or a predetermined sorting step such as water washing, more specifically, stable in water without ionization. Therefore, in this state, slaked lime Ca (OH) ₂ cannot be added to generate stable (CaF ₂ and Ca ₃ (PO ₄ ) ₂ ), in other words, cannot be immobilized.
Therefore, by adding an acid to the lithium hexafluorophosphate aqueous solution and holding the aqueous solution on the acid side, it is considered to promote (hydrolysis) decomposition as shown in the following formula 1). It was found that the (hydro) degradation is not promoted much even if the acid is added or the concentration of the acid is increased. In addition, increasing the concentration of acid also causes equipment corrosion and safety problems.
LiPF ₆ + 5H ₂ O → LiOH + HF + PO (OH) ₃ ... 1)
[0013]
Therefore, as a result of various experiments, the present applicant has accelerated the (hydrolysis) by using an acid aqueous solution in which the acid is heated, specifically, an acid aqueous solution heated to 65 ° C. to 100 ° C. (temperature not boiling). Turned out to be.
[0014]
The acid used in the present invention must have an ionic strength higher than that of HF (hydrofluoric acid) in the case of the acid {1) produced by hydrolysis. For example, as shown in FIG. The table showing the relationship between the concentration of the acid aqueous solution and the ionic strength disclosed in H.4th Edition II-323 (Edition of the Chemical Society of Japan) shows that the ionic strength higher than that of HF is HClO ₄ , HCl. , H ₂ SO ₄ , and when the HF concentration is low, HNO ₃ is also included in the range.
And since these have the high ionic strength with respect to HF even in the dilute acid aqueous solution with a low density | concentration, the hydrolysis of said 1 type | formula is promoted efficiently.
[0015]
In addition, the aqueous solution after the hydrolysis can generate stable (CaF ₂ and Ca ₃ (PO ₄ ) ₂ ) such as 2) and 3) below by adding slaked lime Ca (OH) ₂ .
Ca (OH) ₂ + HF → CaF ₂ + 2H ₂ O 2)
3Ca (OH) ₂ + 2PO (OH) ₃ → Ca ₃ (PO ₄ ) ₂ + 6H ₂ O ... 3)
[0016]
Therefore, it is preferable to use dilute hydrochloric acid or dilute strong acid aqueous solution such as dilute sulfuric acid or dilute nitric acid, and the dilute hydrochloric acid is about 65 ° C. or higher, preferably 90-100. It is preferable to use the product after heating it to around 0 ° C.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Only.
FIG. 1 is a flowchart showing a disassembly process of the lithium ion battery according to the first embodiment of the present invention.
[0018]
First, the waste battery 1 which is the object of this embodiment is a lithium ion secondary battery in which a plurality of battery cells are housed in a plastic case, and the plastic case occupies 20% by weight.
On the positive electrode side, a positive electrode active material such as lithium cobaltate is applied on the aluminum foil with a coating agent, and on the negative electrode side, a graphite negative electrode active material is then applied on the copper foil with a coating agent. Yes.
[0019]
Next, as the electrolyte, for example, ethylene carbonate, diethylene carbonate, dimethyl carbonate, diethyl ether or the like alone or a mixture of two or more fluorine compounds such as lithium hexafluorophosphate LiPF ₆ may be used alone or in combination of two or more. An organic electrolyte in which is dissolved is used. The separator uses a porous polypropylene film.
The battery cell is a case cell made of a nickel-plated steel plate and a spiral body formed by interposing a separator between the sheet-like positive electrode current collector and the sheet-like negative electrode current collector together with the organic electrolyte. Enclosed.
[0020]
The disassembly process of the lithium ion secondary battery having such a configuration will be described with reference to FIG.
First, after the battery 1 is frozen in the freezing breakage step (S1), only the plastic case 2 is broken by the impact force of ball vibration, so that the battery cell accommodated in the waste battery 1 is stored. Is extracted from the plastic case 2.
[0021]
Next, utilizing the fact that the battery cell case is magnetic iron, the battery cell and the plastic case 2 are separated and removed in a magnetic separation step (S2) by a magnetic separator. In this manner, only the plastic case 2 can be broken and separated from the system in the initial state without breaking the battery cell.
[0022]
Next, the battery cells separated and exposed from the plastic case 2 are frozen and crushed (S3) in an inert gas atmosphere in which the battery cells are frozen at about -50 ° C.
The reason why the temperature is set to about −50 ° C. is to set it to −43 ° C. or lower which is the melting point of diethyl carbonate which is an ambient temperature solvent.
The battery cell in the solidified state is frozen and crushed by a cutter mill, a hammer mill or the like in an inert gas atmosphere at -50 ° C.
By this crushing, the aluminum foil of the positive electrode and the copper foil of the negative electrode housed in the battery can be crushed to a few cm square.
[0023]
According to this freeze crushing step (S3), the processing atmosphere temperature is maintained below the melting point of the electrolyte solvent (for example, around −50 ° C., hereinafter referred to as “freezing low temperature”), and the processing space is inert gas (or high dry air). ) As a result of maintaining below, prevention of generation of flammable hydrogen gas due to reaction of reactive active lithium with moisture in ambient air, prevention of oxygen generation from battery components, prevention of ignition of generated gas, moisture of electrolyte and ambient air It is possible to prevent the generation of toxic gas due to the reaction.
[0024]
Next, in the magnetic separation process (S4) which consists of a magnetic separator, it isolate | separates into the iron part of a battery cell case, and the magnetic selection remainder inside.
The battery cell case separated in the magnetic separation step (S4) and the electrolyte attached to the case are washed in the water washing step (S11), and then only the iron 3 is separated and recovered.
The reason for this water washing is that the lithium hexafluorophosphate that is an electrolyte attached to the iron portion during crushing, and the ethylene carbonate and dimethyl carbonate that are solvents are used in the aqueous solution by the water washing step (S11). In addition, lithium cobaltate coated with polybilidene chloride peeled off from the aluminum foil of the positive electrode and adhered to the iron part has a fine particle size of 5 μm, is insoluble in water, and has a specific gravity of about 5 Therefore, it can be dispersed in water and separated from the iron 3 in the water washing step (S11). Further, acetylene black peeled off from the positive electrode aluminum foil, negative electrode side graphite (spherical graphite), and the like can be dispersed in water in the water washing step (S11).
[0025]
The magnetic separation residue separated in the magnetic separation step (S4) is heated at about 300 ° C. for 10 minutes in the heating step (S5), and then subjected to ultrasonic vibration for 15 minutes using the ultrasonic vibrator (S6). Subsequently, for example, sieving is performed with a 0.3 mm sieve (S7).
That is, in the heating step (S5), lithium cobalt oxide and graphite (spherical graphite) are first peeled from the positive electrode aluminum foil and negative electrode copper foil, and then sieved (S7).
[0026]
At that time, the solvents ethylene carbonate, dimethyl carbonate, polybilidene chloride and lithium hexafluorophosphate are diffused or decomposed. Furthermore, polypropylene or polyethylene as a separator decomposes and burns. Then, the gas generated in the heating step (S5) is processed in the roasting operation (S8) together with the gas generated in other operations, or is directly introduced into the exhaust gas processing (S9).
[0027]
More specifically, the polybilidene chloride in which acetylene black constituting the positive electrode and lithium cobaltate are bonded by heating the magnetic separation residue to about 300 to 500 ° C. in an inert gas atmosphere. Pyrolyzes. By this thermal decomposition, the adhesive force between acetylene black, lithium cobalt oxide and aluminum foil is reduced, and further, in this state, ultrasonic vibration is performed using an ultrasonic vibrator (S6), whereby acetylene black and lithium cobalt oxide are obtained. 7 can be separated from the aluminum foil.
[0028]
Similarly, the adhesion between the copper foil and the applied graphite is reduced due to thermal decomposition of the polybilidene chloride on the negative electrode side, and in this state, ultrasonic vibration is applied using the ultrasonic vibrator (S6). By performing the above, graphite can be separated from the copper foil.
At that time, ethylene carbonate, dimethyl carbonate, polybilidene chloride and lithium hexafluorophosphate as solvents can be removed or decomposed, and polypropylene or polyethylene as a separator can be removed out of the system by decomposition and combustion. Guided to S9).
[0029]
The small particle size lithium cobaltate 7 and carbon such as acetylene black and graphite are separated from the copper foil and the aluminum foil by sieving treatment (S7) following the ultrasonic vibration treatment (S6).
[0030]
In addition, since there exists a possibility that the substance mentioned later other than aluminum foil and copper foil may adhere on the said sieve, water washing (S12) is performed.
That is, the copper foil and the aluminum foil separated on the sieve are washed with water (S12), and lithium hexafluorophosphate and polybilidene chloride, which are attached to the electrolyte, and ethylene carbonate and dimethyl carbonate, which are the solvents, are in an aqueous solution. Lithium cobaltate 7 dissolved in the copper foil and aluminum foil and the applied acetylene black have a very small particle size and are insoluble in water, so they are dispersed in water in water washing (S12). The copper foil and the aluminum foil 4 are separated and collected. Further, lithium cobaltate + carbon 6 is separated under the sieve.
[0031]
Carbon 6 such as lithium cobaltate + acetylene black and graphite separated under sieving by sieving (S7) includes polybilidene chloride, lithium hexafluorophosphate adhering thereto, and ethylene carbonate and dimethyl carbonate as solvents. Together with granulation (S13), roasting with fuel 8 together with ethylene carbonate and dimethyl carbonate, which are solvents generated during the operations of the freeze crushing step (S3), magnetic separation step (S4), and heating step (S5) (S8) Then, the carbon content is burned by the roasting (S8), and the lithium cobalt oxide 7 is recovered.
[0032]
The exhaust gas generated by the roasting (S8) is subjected to an exhaust gas treatment (S9) comprising an absorption tower for injecting the Ca (OH) ₂ solution 5 and then further treated by a wastewater treatment / solid-liquid separation treatment tank (S10). Lithium hexafluorophosphate is separated from the waste water 11 and collected as solid waste 10 (CaF ₂ and Ca ₃ (PO ₄ ) ₂ ).
That is, by the exhaust gas treatment (S9), the fluorine compound and the phosphate compound generated from lithium hexafluorophosphate react with the Ca (OH) ₂ solution 5 to cause Ca ₃ F ₂ and Ca ₃ that are hardly soluble in water. Utilizing the property that (PO ₄ ) ₂ is generated, solid waste 10 (in a waste water treatment / solid-liquid separation treatment tank (S10) in which a Ca (OH) ₂ solution 5 is added together with a dilute HCl aqueous solution heated to 95 ° C. It can be separated from the waste water 11 and recovered as CaF ₂ and Ca ₃ (PO ₄ ) ₂ ).
[0033]
During the heating step (S5) and roasting (S8) operations, lithium fluoride, which is a reaction product from lithium hexafluorophosphate, is separated into water by washing with water (S11) and (S12), respectively. Is done.
Therefore, the aqueous solution washed with water (S11) and (S12) is also led to the wastewater treatment / solid-liquid separation treatment tank (S10), first hydrolyzed with an aqueous HCl diluted hydrochloric acid solution heated to 95 ° C., and then hydrolyzed in the water. Utilizing the property that the generated fluorine ion reacts with the Ca (OH) ₂ solution 5 to generate CaF ₂ that is hardly soluble in water, the solid waste 10 (CaF) is obtained by waste water treatment to which the Ca (OH) ₂ solution 5 is added. ₂ and Ca ₃ (PO ₄ ) ₂ ) can be separated from the waste water 11 and recovered.
[0034]
Next, the gist of the present invention will be specifically described.
As described above, the lithium hexafluorophosphate aqueous solution gas-separated from the heating step (S5) or the like and contained in the water in the water washing steps (S11) (S12) or the exhaust gas generated by the roasting (S8) (OH) ₂ solution 5 exhaust gas treatment made from the absorption tower for injection (S9) a having undergone, lithium hexafluoro phosphoric acid aqueous solution, to stabilize the aqueous solution as it is, waste water treatment / solid-liquid separation As described above, dilute hydrochloric acid 9 is added in the treatment tank (S10) and the aqueous solution is maintained on the acid side to promote (hydrolysis) of the following formula 1).
LiPF ₆ + 5H ₂ O → LiOH + HF + PO (OH) ₃ ... 1)
[0035]
In this case, as is clear from FIG. 2, in order to promote (hydrolysis), a strong acid aqueous solution (20% HCl aqueous solution, room temperature) with an increased acid concentration at room temperature can achieve only about 28% of the (hydrolysis). It turned out that it was not promoted much.
In addition, since raising the concentration of the acid also has problems of equipment corrosion and safety, a dilute hydrochloric acid aqueous solution (1% HCl aqueous solution) whose acid concentration was greatly reduced to 1% was heated to 65 ° C. and used. It was found that the (hydro) degradation was achieved by 40% or more.
[0036]
Furthermore, when dilute hydrochloric acid aqueous solution (1% HCl aqueous solution) was heated to 95 ° C. and used, it was found that the (hydrolysis) was achieved 100%.
Next, when a dilute aqueous hydrochloric acid solution heated to 95 ° C. was used with a concentration increased to 2%, it was found that the reaction time for the (hydrolysis) was shortened.
[0037]
That is, as a result of the experiment, by using an acid aqueous solution heated to the dilute hydrochloric acid having a concentration of 1 to 2%, specifically, heated to 65 ° C. to 100 ° C. (temperature that does not boil), the (hydrolysis) can be rapidly performed. It was found to be promoted.
[0038]
Next, an experiment similar to that described above was performed using dilute sulfuric acid. As is clear from FIG. 3, (hydrolysis) decomposition was achieved as little as 17% in (30% H ₂ SO ₄ aqueous solution, room temperature), and not much. It turned out not to be promoted.
Further, when a 10% H ₂ SO ₄ aqueous solution was heated to 65 ° C. and used, the (hydrolysis) was achieved by 50% or more.
[0039]
Furthermore, when the H ₂ SO ₄ aqueous solution having a concentration of 5%, 10%, 20%, and 30% was heated to 95 ° C., 100% of the (hydrolysis) was achieved. There was found.
Next, when the concentration of the heated H ₂ SO ₄ aqueous solution at 95 ° C. is 10% or more, the reaction time of the (hydrolysis) is short for both 20% and 30%, and there is not much difference. found.
[0040]
From these experimental results, the acid used in the present invention can be either HCl or H ₂ SO ₄ as long as its ionic strength is higher than that of HF (hydrofluoric acid)} in the case of the acid {1) produced by hydrolysis. It was also found that 100% (hydrolysis) degradation was achieved even at a lower concentration of HCl.
[0041]
Then, slaked lime Ca (OH) ₂ can be added to the hydrolyzed aqueous solution to generate stable (CaF ₂ and Ca ₃ (PO ₄ ) ₂ ) such as 2) and 3) below.
Ca (OH) ₂ + HF → CaF ₂ + 2H ₂ O 2)
3Ca (OH) ₂ + 2PO (OH) ₃ → Ca ₃ (PO ₄ ) ₂ + 6H ₂ O ... 3)
[0042]
Although the effect which is the gist of the present invention is as described above, the function and effect of the embodiment accompanying the present invention will be briefly described with reference to FIG.
In the water washing step (S11) after freeze crushing (S3), lithium hexafluorophosphate as an electrolyte adhering to the iron portion during crushing, and ethylene carbonate and dimethyl carbonate as solvents are separated into water, and the positive electrode aluminum The lithium cobalt oxide 7 peeled off from the foil and adhered to the iron portion could be dispersed in water and separated from the iron 3 respectively.
Further, by washing with water (S12, S11), lithium cobaltate 7 could be separated from lithium fluoride which is a reaction product from lithium hexafluorophosphate.
[0043]
Also, granulated lithium cobaltate 7+ acetylene black and graphite 6 such as graphite separated under the sieving (S7) together with the remaining polybilidene chloride and lithium hexafluorophosphate in the heating step (S5). By (S13), it became possible to prevent scattering by powder and to perform efficient combustion in roasting (S8).
Further washing with water (S12, S11) By performing granulation (S13) using water, lithium cobaltate 7 recovered by washing with water after magnetic separation and lithium hexafluorophosphate adhering to the iron portion, polybilidene chloride, The incineration by the subsequent roasting step (S8) was able to efficiently treat ethylene carbonate and dimethyl carbonate.
[0044]
Further, after being hydrolyzed by a dilute HCl aqueous solution heated to 95 ° C., the fluorine ions hydrolyzed in the water are treated in a wastewater treatment / solid-liquid separation treatment tank (S10) to which a Ca (OH) ₂ solution 5 is added. By the waste water treatment, the fluorine compound and phosphoric acid compound generated from lithium hexafluorophosphate were separated from the waste water 11 and recovered as solid waste 10 (CaF ₂ and Ca ₃ (PO ₄ ) ₂ ).
[0045]
【The invention's effect】
As described above, according to the present invention, by using an acid aqueous solution heated to 65 ° C. to 100 ° C., the (hydrolysis) is rapidly promoted, and the hydrolyzed aqueous solution is slaked lime Ca (OH) _2. Can be added to produce stable (CaF ₂ and Ca ₃ (PO ₄ ) ₂ ).
Therefore, according to the invention, the lithium hexafluorophosphate separated in the aqueous solution is decomposed into fluoride ions and phosphate ions by (hydrolysis), and then fixed by adding a fixing agent such as slaked lime to the ion aqueous solution. Can be processed safely.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a disassembly process of a lithium ion battery according to an embodiment of the present invention.
FIG. 2 is a table showing the acid decomposition behavior of lithium hexafluorophosphate separated in an aqueous solution with hydrochloric acid.
FIG. 3 is a table showing the acid decomposition behavior of lithium hexafluorophosphate separated in an aqueous solution with sulfuric acid.
FIG. 4 is a table showing the relationship between the concentration of an acid aqueous solution and the ionic strength (Source: Chemical Handbook Basic Revised 4th Edition II-323, The Chemical Society of Japan).
[Explanation of symbols]
1 Waste Battery 5 Ca (OH) ₂ Solution 10 Solid Waste (CaF ₂ and Ca ₃ (PO ₄ ) ₂ )
11 Wastewater S1 Plastic case freezing and breaking step S3 Battery cell freezing and crushing step S5 Heating step S7 Screening S8 Roasting step S9 Exhaust gas treatment S10 Waste water treatment / solid-liquid separation treatment S11, S12 Water washing step

Claims (4)

In a method for treating a battery containing a salt comprising a cation and a Lewis acid ion as an electrolyte in the battery,
The battery crushed material containing the salt is washed with water to separate the salt into an aqueous solution, and then a heated aqueous acid solution is added to the aqueous solution containing the salt to promote decomposition of the Lewis acid ion, and the ion A battery treatment method comprising fixing a Lewis acid ion decomposition product by adding a fixing agent such as slaked lime to an aqueous solution. In a method for treating a battery containing a salt comprising a cation and a Lewis acid ion as an electrolyte in the battery,
Heating the battery crushed material containing the salt by means of pyrolysis or roasting, and including the salt in the exhaust gas;
An exhaust gas treatment step of bringing the salt into contact with an aqueous fixative solution such as slaked lime and the salt in the aqueous fixative solution;
A heated acid aqueous solution is added to the aqueous solution capturing the salt in the exhaust gas treatment step to promote decomposition of the Lewis acid ion, and a fixing agent such as slaked lime is added to the ion aqueous solution to produce a Lewis acid ion decomposition product. and the step of fixing the,
A battery treatment method comprising: In a method for treating a lithium ion battery containing lithium hexafluorophosphate as an electrolyte in the battery,
After adding a heated acid aqueous solution to the lithium hexafluorophosphate-containing aqueous solution separated by a predetermined sorting process and decomposing it into fluoride ions and phosphate ions, a fixing agent such as slaked lime is added to the ion aqueous solution and fixed. A process for treating a battery comprising the step of: The heated acid aqueous solution according to claim 1, 2 or 3 is an acid aqueous solution of HCl, H ₂ SO ₄ , HNO ₃ , HClO ₄ , and the heating temperature is 65 ° C. to 100 ° C. Battery processing method.

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