JP2019099874A - Recovery method of lithium - Google Patents

Abstract

To provide a method for more easily recovering lithium from a manufacturing process wastewater of a positive electrode material for lithium secondary battery containing lithium and aluminum, and reducing recovery cost.SOLUTION: There is provided a recovery method of lithium for recovering lithium from manufacturing process wastewater containing lithium and aluminum of a positive electrode material for lithium secondary battery, having an adsorption process S2 for selectively adsorbing a lithium ion to an ion exchange resin by contacting the ion exchange resin with the manufacturing process wastewater, and an elution process S3 for making a solution containing acid or sodium salt in contract with the ion exchange resin to which the lithium ion is selectively adsorbed in the adsorption process S2 to elute the lithium ion from the ion exchange resin, in which the ion exchange resin is a weakly acidic cation exchange resin having a sulfonic acid group or a sodium salt type functional group thereof.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lithium recovery method for recovering lithium from manufacturing process waste water containing lithium and aluminum of a positive electrode material for a lithium secondary battery.

  Lithium is widely used in industries such as additives for pottery and glass, glass flux for continuous casting of steel, grease, medicine, battery and the like. In particular, since lithium secondary batteries have high energy density and high voltage, their use as batteries for electronic devices such as laptop computers and as car batteries for electric vehicles and hybrid vehicles has recently expanded, and demand is rapidly increasing. ing.

  In recent years, in order to effectively utilize resources, it has been promoted to recover lithium from waste water discharged in the manufacturing process of a positive electrode material for lithium secondary batteries (hereinafter, also referred to as “manufacturing process drainage”).

  For example, lithium and aluminum are contained in the manufacturing process drainage in the nickel-based positive electrode material (NCA). Although it is necessary to separate lithium and aluminum in order to recover lithium from this manufacturing process waste water, the neutralization precipitation method is proposed in Patent Document 1 as a separation method, and the solvent extraction method is proposed in Patent Documents 2 and 3.

JP 2004-33984 A JP, 2012-211386, A Japanese Patent Application Publication No. 2002-121623

  However, in the neutralization precipitation method of Patent Document 1 and the solvent extraction method of Patent Document 2, lithium remains in the production process wastewater after aluminum separation. Since the concentration of lithium remaining in the manufacturing process wastewater is low, in order to recover lithium as a carbonate or hydroxide salt, it is necessary to evaporate the manufacturing process wastewater and concentrate the lithium. For this reason, there is a problem that the cost of recovering lithium increases and it is economically unpreferable.

  In the solvent extraction method of Patent Document 3, crown ether is used to separate lithium from production process wastewater, and then lithium is extracted back from crown ether. Since this method enables concentration of lithium during back extraction, it does not require concentration by evaporation and is cost effective. However, crown ether is expensive, and the solvent extraction method requires waste water treatment, which complicates the process, resulting in an increase in the cost of lithium recovery.

  The present invention has been made in view of the above problems, and provides a method for more simply recovering lithium from waste water of manufacturing process of positive electrode material for lithium secondary battery containing lithium and aluminum and reducing the recovery cost The purpose is

  One aspect of the present invention is a method for recovering lithium from manufacturing process waste water containing lithium and aluminum of positive electrode material for lithium secondary battery, which comprises contacting ion exchange resin with the production process waste water to carry out ion exchange Elution process in which an aqueous solution containing sodium salt is brought into contact with an ion exchange resin in which lithium ions are selectively adsorbed to the resin, and an ion exchange resin in which lithium ions are selectively adsorbed in the adsorption process to elute lithium ions from the ion exchange resin And the ion exchange resin is characterized in that the ion exchange resin is a strongly acidic cation exchange resin having a sulfonic acid group or a functional group of its sodium salt type.

  In this way, lithium can be selectively recovered from the wastewater in the manufacturing process. And since lithium can be concentrated without the process of evaporating manufacturing process waste water and concentrating lithium, lithium can be recovered more simply and recovery cost can be reduced.

  In one embodiment of the present invention, the pH of the production process waste water in the adsorption step may be 9 or more.

  In this way, in the adsorption step, aluminum and lithium in the manufacturing process wastewater can be separated, and inhibition of the ion exchange reaction can be prevented, so lithium can be recovered more easily and recovery cost can be reduced. It can be reduced.

  Further, in one aspect of the present invention, the lithium concentration of the production process wastewater in the adsorption step may be 0.3 g / L or more.

  In this way, lithium ions with low selectivity can be adsorbed to the ion exchange resin in the adsorption step.

  In one aspect of the present invention, the substitution step further includes a substitution step of substituting a functional group contained in the ion exchange resin before the adsorption step, and the substitution step is a sodium salt type from a sulfonic acid group. May be replaced by

  In this way, it is possible to prevent a decrease in pH in the adsorption step and to prevent the ion exchange reaction in the adsorption step from being inhibited.

  In one aspect of the present invention, the sodium salt in the elution step may be sodium sulfate.

  For example, when sodium chloride is used in the elution step, chlorine remains in the precipitated and collected lithium carbonate, but since chlorine can be prevented from remaining in the precipitated and recovered lithium carbonate in this way, the facility using chlorine Can prevent the corrosion of structural materials.

  According to the present invention, lithium can be selectively recovered from the production process waste water, and lithium can be concentrated without the process of evaporating the production process waste water and concentrating lithium, so lithium and aluminum containing lithium It is possible to more simply recover lithium from the production process drainage of the positive electrode material for the next battery, and to reduce the recovery cost.

It is a flowchart which shows the outline of the manufacturing process of the positive electrode material for lithium secondary batteries. It is a flow figure showing an outline of a recovery method of lithium concerning one embodiment of the present invention. FIG. 2 is a view showing an adsorption curve (a relationship between BV and lithium and aluminum concentrations in a solution after adsorption) in Example 1. FIG. 6 is a diagram showing an elution curve (a relationship between BV and lithium and aluminum concentrations in the eluent) in Example 1. It is a figure which shows the adsorption curve (The relationship between BV and lithium and aluminum concentration in the liquid after adsorption) in Comparative Example 1. It is a figure which shows the elution curve (The relationship between BV and lithium and aluminum concentration in an eluting solvent) in Comparative Example 1.

  Hereinafter, specific embodiments of the present invention (hereinafter, referred to as “the present embodiments”) will be described in detail. In addition, this invention is not limited to the following embodiment at all, Within the range of the objective of this invention, a change can be added suitably and can be implemented.

[1. Outline of manufacturing process of positive electrode material for lithium secondary battery]
First, an outline of a production process of a positive electrode material for a lithium secondary battery will be described using the drawings. FIG. 1 is a flow chart showing an outline of the production process of a positive electrode material for a lithium secondary battery. As shown in FIG. 1, the manufacturing process of the positive electrode material for lithium secondary battery is composed of a crystallization process S101, a separation process S102, a baking process S103, and a water washing process S104. Specifically, in the crystallization step S101, an aqueous solution of sodium hydroxide is added to a mixed aqueous solution of metal salts of sulfates made of raw materials such as nickel, cobalt, or aluminum, and these metal hydroxides are coprecipitated to obtain a metal. It is a process of obtaining the slurry containing hydroxide. The separation step S102 is a step of separating the metal composite hydroxide from the obtained slurry containing the metal hydroxide by solid-liquid separation or the like. In the firing step S103, the obtained metal composite hydroxide and lithium hydroxide are mixed, and the mixture is fired at a predetermined temperature to obtain a lithium metal composite oxide. The water washing step S104 is a step of water washing the obtained lithium metal composite oxide.

In the water washing step S104 of the manufacturing process of the positive electrode material for lithium secondary battery, since the positive electrode material is washed with water, waste water containing lithium ions and aluminum ions at high concentration is discharged.
The drainage concentration is, for example, 1 to 4 g / L for lithium ions, and 0.04 to 0.18 g / L for aluminum ions. It is not preferable to discharge such drainage into public water areas because lithium is an industrially useful metal. And, in recycling of resources, it is required to recover and effectively use lithium discharged in the manufacturing process without discarding.

  As described above, for example, since the wastewater in the production process of NCA is an aqueous solution containing lithium and aluminum, separation of aluminum is required when recovering a lithium compound from the wastewater in the production process.

  In order to separate aluminum from an aqueous solution containing aluminum and lithium, there are a neutralization precipitation method (for example, Patent Document 1), a solvent extraction method (for example, Patent Documents 2 and 3), an ion exchange method, and the like.

  In the neutralization precipitation method, pH adjustment is performed in a pH range in which aluminum becomes a hydroxide, and aluminum is separated as a precipitate. Lithium remains in the aqueous solution using this method.

  In the solvent extraction method, an acidic extractant having, for example, a carboxylic acid or phosphoric acid as a functional group is widely used, but the acidic extractant is generally more difficult to extract as the metal of the formed oxide has higher basicity. Therefore, lithium is more difficult to extract than aluminum. For this reason, aluminum is extracted and separated. Lithium also remains in the aqueous solution when this method is used.

  In the ion exchange method, a cation exchange resin or a chelate resin is widely used to capture cations, but since there is no resin that selectively captures lithium compared to aluminum, aluminum is captured and separated from the solution. Lithium also remains in the aqueous solution when this method is used.

  As described above, there are many separation methods in which aluminum is selectively removed to leave lithium in the solution, but when lithium is to be recovered as a carbonate or hydroxide, it is disadvantageous when the lithium concentration in the solution is low. become. For example, when it is intended to recover lithium carbonate, a carbonated source such as sodium carbonate is added to precipitate lithium carbonate for recovery, but lithium carbonate has a solubility of about 13 g / L at 20 ° C. It must be above this concentration. By adjusting the conditions, it is possible to increase the lithium concentration by adjusting the conditions for the leachate of ores and process intermediate products, but it may become economically unfavorable situations such as consuming a large amount of acid to lower the pH at the time of leaching. There is. In addition, since the lithium concentration in the manufacturing process waste water is usually kept low to reduce losses, the lithium concentration in this case is hardly exceeded.

  For this reason, when the lithium concentration in the manufacturing process waste water is low, concentration needs to be performed. Even if it is intended to recover with lithium hydroxide, lithium hydroxide is often converted by adding slaked lime to lithium carbonate, so it is necessary to concentrate it to obtain an intermediate product lithium carbonate.

  Evaporative concentration is known as a well-known concentration method, but to evaporate water requires a large amount of energy at 539 kcal / kg at standard atmospheric pressure, resulting in high energy costs, which is not economically preferable.

  The solvent extraction method and the ion exchange method extract or adsorb the metal to be recovered, and then perform back extraction or elution to obtain a purified aqueous solution, but by adjusting the flow rate of the back extract solution or the eluent, the recovery object can be recovered Metals can be concentrated. Therefore, if lithium can be selectively extracted or adsorbed, it is possible to obtain a purified liquid having a lithium concentration capable of precipitating lithium carbonate without using a high energy cost evaporative concentration method.

  As an extracting agent or resin capable of selectively extracting an alkali metal or alkaline earth metal, an extracting agent or resin having a crown ether which is a macrocyclic compound as a functional group is known (for example, Patent Document 3). Crown ethers are known to form complexes by incorporating metal ions into the ring and are selective for metal ions having an ionic radius that matches the ring radius. It is known that crown ethers of carbon and oxygen, which constitute the ring, particularly have affinity to alkali metals and alkaline earth metals, and 12-crown-4 specifically forms a complex with lithium. However, crown ethers are water soluble and thus are not suitable for solvent extraction methods that require phase separation. It may be considered to modify crown alkyl ether to a lipophilic alkyl group or the like to make it water insoluble property, but if special synthesis is required and it is attempted to be used industrially, the cost becomes expensive. And utilization is not realistic due to the problem that supply stability can not be maintained.

  Furthermore, in the solvent extraction method, since the organic phase is mixed in the state of minute droplets in the extraction residue after extraction, in order to discharge the waste water usually, an activated carbon treatment or the like is required. In addition, water-soluble impurities derived from organic solvents such as extractants and water-soluble decomposition products are dissolved in the aqueous phase, and COD in the waste water is increased, so waste water treatment such as oxidative decomposition treatment is required, and the process is complicated. And the processing cost tends to be high.

  For this reason, the simplest method is to use a resin on which crown ether is supported. However, crown ether is expensive in its reagent itself, and the resin is also expensive. Currently, practical examples can only be used as a column for analysis. There is no. Therefore, large-scale purification using crown ethers is currently at a cost disadvantage.

  Due to such problems, there has been a demand for a simple method for selectively recovering lithium from an aqueous solution containing aluminum and lithium to obtain an aqueous solution having a concentration suitable for obtaining lithium carbonate or lithium hydroxide. .

  In view of such circumstances, as a result of intensive investigations, the inventors adjusted the production process wastewater containing aluminum and lithium to a predetermined pH and adjusted the functional group to a sodium type (hereinafter referred to as Na type). Adsorption step in which lithium ions are selectively adsorbed to leave aluminum ions in the solution by contacting with a strongly acidic cation exchange resin having a sulfonate group, and strongly acidic cation exchange using an aqueous solution containing sodium salt A concentration suitable for obtaining lithium carbonate and lithium hydroxide by selectively recovering lithium selectively from manufacturing process waste water containing aluminum and lithium simply by combining the elution step of eluting lithium ions adsorbed to the resin. It has been found that it is possible to make an aqueous solution of the present invention, and the present invention has been completed.

[2. Lithium recovery process]
The method of recovering lithium according to the present embodiment recovers lithium from the process water of the manufacturing process of the positive electrode material for lithium secondary battery, and includes a replacement process, an adsorption process, and an elution process. Hereinafter, the outline and each process of the recovery method of lithium are each demonstrated.

[2-1. Outline of Lithium Recovery Method]
First, an outline of a method for recovering lithium will be described using the drawings. FIG. 2 is a flowchart showing an outline of a method for recovering lithium. The method for recovering lithium according to one embodiment of the present invention is, as shown in FIG. 2, composed of a substitution step S1, an adsorption step S2, and an elution step S3.

2-2-1. Replacement process]
The substitution step S1 substitutes a sulfonic acid group (hereinafter also referred to as "H-type"), which is a functional group contained in the strongly acidic cation exchange resin, into a sodium type (hereinafter also referred to as "Na-type"). It is a process. The reason why the H-type is replaced with the Na-type in this embodiment will be described in the section of the adsorption step. In addition, since the adsorptivity of the strongly acidic cation exchange resin with respect to lithium ions is reduced by repeating the adsorption step and the elution step described later a plurality of times, the substitution step can also be performed for the purpose of regenerating the adsorption. . The substitution step can be omitted when the strongly acidic ion exchange resin is in the Na type.

2-2-2. Adsorption process]
In the adsorption step S2, the strongly acidic cation exchange resin is brought into contact with the production process waste water to selectively adsorb lithium ions to the strongly acidic cation exchange resin. The lithium solution containing aluminum and lithium may have any metal concentration. However, by adjusting the pH of the aqueous solution to 9 or more, the aluminum ion is converted to an aluminate ion [Al (OH) ₄ ] ⁻ . When this solution is passed through a strongly acidic cation exchange resin containing sulfonic acid groups adjusted to Na type, lithium ions which are cations are adsorbed, but aluminate ions which are anions are not adsorbed. Here, the aluminum ion is more selective than the lithium ion. Therefore, when aluminum ions are present in the manufacturing process waste water, it is difficult to selectively adsorb lithium to the strongly acidic cation exchange resin. Therefore, in the adsorption step according to one embodiment of the present invention, lithium ions can be selectively adsorbed by converting aluminum ions into aluminate ions. At this time, when the functional group is a hydrogen type (hereinafter, described as H type), hydrogen ions exchanged with lithium ions are released into the aqueous solution, and the pH in the vicinity of the resin is lowered. In this case, aluminum hydroxide having poor filterability precipitates and adheres to the resin to inhibit liquid permeation and ion exchange reaction. In the worst case, the adsorption step using a column becomes impossible. When the pH in the vicinity of the resin is further lowered to reach an acidic region where aluminum is present as a cation, it is selectively adsorbed more than lithium ions, making separation difficult. In the case of a strongly acidic cation exchange resin, since a base such as the above-mentioned aluminum hydroxide is decomposed and ion-exchanged with aluminum for adsorption, it becomes difficult to separate from lithium.

  However, by adjusting to Na-type in advance, such pH decrease is prevented and the formation of aluminum hydroxide and aluminum ion is suppressed, and aluminum can be held in the state of aluminate ion, so it is adsorbed to the resin. There is nothing to do. Since lithium ion is inferior in selectivity to sodium ion and lithium ion, lithium concentration needs to be 0.3 g / L or more in order to adsorb lithium ion in Na type, and 0.5 g / L or more It is desirable to have. If the lithium concentration in the manufacturing process wastewater is less than 0.3 g / L, lithium ions may be difficult to be adsorbed to the Na-type strong acid cation exchange resin. In addition, since a strongly acidic cation exchange resin has high durability, more adsorption processes and elution processes can be performed as compared with a weakly acidic cation exchange resin having a carboxy group as a functional group.

2-2-3. Elution process]
In the elution step S3, lithium ions are eluted using an aqueous solution containing a sodium salt. For example, an aqueous solution of sodium sulfate can be used. The cation exchange resin is usually eluted using an acid, but in the case of adsorption and elution using a column, if the liquid passed through in the adsorption step remains, the pH drops due to the mixing of the liquid and aluminum hydroxide The precipitation of aluminum occurs in the form of cations in the acidic region and is adsorbed to the resin.

  The same applies to the transition from the elution step to the adsorption step, and the pH of the aqueous solution containing aluminum and lithium adjusted to pH 9 or more is lowered by mixing with the remaining acid, and the pH drops aluminum hydroxide. The precipitation of aluminum occurs in the form of cations in the acidic region and is adsorbed to the resin.

  Although it is conceivable to provide a thorough washing step between each step as a workaround for such a problem, in the strongly acidic cation exchange resin, since the strong acid is usually used for elution, the liquid in the column is near neutrality. A large amount of water is required to wash the water until it reaches the point, and disadvantages such as a decrease in throughput and an increase in waste water treatment load are not practical.

  Furthermore, when it elutes with an acid, since the functional group becomes H type, it is necessary to pass an aqueous solution containing a sodium salt to carry out the next adsorption step, and there is a disadvantage that the number of steps increases. If an aqueous solution containing sodium is used as the eluent, problems due to pH fluctuation can be avoided, and the functional group can be returned to the Na type simultaneously with elution, so the process is simplified. In addition, by adjusting the flow rate of the eluent, lithium in the eluent can be concentrated. Therefore, lithium can be recovered without using a high energy cost evaporation method.

  The eluent is an aqueous solution containing lithium and sodium, but using sodium salt does not adversely affect the precipitation of lithium carbonate because sodium carbonate is added to precipitate lithium carbonate for recovery. The obtained lithium carbonate is required to have a grade according to the application, but by washing with water if necessary, the concentration of sodium which is an impurity can be reduced.

  Sodium salts include sodium chloride and sodium sulfate, but when sodium chloride is used, chlorine remains in precipitated lithium carbonate. The recovered lithium carbonate is recycled as a raw material of the positive electrode material of the secondary battery, but it is desirable to use sodium sulfate because chlorine has a disadvantage of corroding the structural material of the facility.

  EXAMPLES Specific examples to which the present invention is applied will be described below, but the present invention is not limited to these examples.

Example 1
[3-1. Replacement process]
50 mL of strongly acidic cation exchange resin (manufactured by Sumika Chemtech Co., Ltd .: Duolite CF20LF) was packed in a glass column having a diameter of 20 mm, and the following operation was repeated three times to convert the resin into Na type.
a) 500 mL (BV10) of 73 g / L aqueous hydrochloric acid solution was passed at SV10.
b) After passing an aqueous hydrochloric acid solution, 500 mL (BV10) of pure water was passed through with SV10 to wash the resin.
c) After washing, 500 mL (BV10) of 50 g / L aqueous sodium sulfate solution was passed through at SV10.

[3-2. Adsorption process]
[3-1. 10 mL of the resin washed in the substitution step were separated and packed in another column of 10 mm in diameter. This column contains 2.0 g / L of lithium, 0.07 g / L of sodium, 0.1 g / L of aluminum, and a pH of about 12 in the manufacturing process of the positive electrode material of the secondary battery cathode 0.6 L (at SV 20) BV60) The solution was passed to adsorb lithium ions. To the resin after adsorption, 2.0 L (BV 200) of pure water was passed at SV20 to wash the remaining liquid.

[3-3. Elution process]
[3-2. A 150 g / L aqueous solution of sodium sulfate was passed through the washed resin in the adsorption step], and 70 mL (BV7) of SV1 was passed to elute the lithium ions adsorbed on the resin.

  [3-1. [3-3. All elution steps] were performed at normal temperature. With respect to the results obtained in Example 1, FIG. 3 shows the adsorption curve (the relationship between BV and the concentrations of lithium and aluminum in the solution after adsorption), and FIG. 4 shows the elution curve (BV and the concentrations of lithium and aluminum in the eluent). Relationship).

Comparative Example 1
In Comparative Example 1, unlike Example 1, the lithium ion contained in the process of producing the positive electrode material for a lithium secondary battery was eluted using the H-type strongly acidic cation exchange resin according to the following operation.

[4-1. Replacement process]
After packing 50 mL of strongly acidic cation exchange resin (manufactured by Sumika Chemtech Co., Ltd .: Duolite CF20LF) in a glass column having a diameter of 20 mm and repeating the following operation twice, for the third time, only a) and b) are carried out And the resin was H-shaped.
a) 500 mL (BV10) of 73 g / L aqueous hydrochloric acid solution was passed at SV10.
b) After passing an aqueous hydrochloric acid solution, 500 mL (BV10) of pure water was passed through with SV10 to wash the resin.
c) After washing, 500 mL (BV10) of 50 g / L aqueous sodium sulfate solution was passed through at SV10.

[4-2. Adsorption process]
[4-1. 10 mL of the resin washed in the substitution step were separated and packed in another column of 10 mm in diameter. This column contains 2.0 g / L of lithium, 0.07 g / L of sodium, 0.1 g / L of aluminum, and a pH of about 12 in the manufacturing process of the positive electrode material of the secondary battery cathode 0.6 L (at SV 20) BV60) The solution was passed to adsorb lithium ions. To the resin after adsorption, 2.0 L (BV 200) of pure water was passed at SV20 to wash the remaining liquid.

[4-3. Elution process]
A 150 g / L aqueous solution of sodium sulfate was passed through the washed resin, and 70 mL (BV7) was passed through with SV1 to elute lithium ions adsorbed on the resin.

<Consideration by Example>
In FIG. 3 showing the adsorption curve of Example 1, the aluminum concentration after BV20 is 0.1 g / L of the stock solution, and it can be seen that it is not adsorbed. Although the aluminum concentration of the solution after adsorption is lowered at BV10, this is due to the dilution effect of the column residual solution, and it can not be determined that it is adsorbed. It can be seen from FIG. 4 showing the elution curve that the eluent containing high concentration of lithium was recovered. On the other hand, it can be seen that aluminum in the eluent was almost zero, and that almost no aluminum was adsorbed in the adsorption step.

  In FIG. 5 showing the adsorption curve of Comparative Example 1, even with BV 20, the concentration of aluminum in the solution after adsorption is low, and it can be confirmed that aluminum is adsorbed as compared with Example 1. In BV10, the aluminum concentration is 0, but even if there is a dilution effect of the residual liquid, it does not become 0 if it is not adsorbed, so it can be seen that aluminum is surely adsorbed. From FIG. 6 showing the elution curve, it is possible to recover the eluent containing high concentration of lithium, but it is understood that the concentration of aluminum in the eluent is high, and it is 15 mg / L or more above BV4. From this, it is understood that, in the case of H-type, aluminum ions are adsorbed in the adsorption step and eluted in the elution step, so that separation from lithium is impossible. From these results, it was found that lithium can be selectively separated from the solution containing aluminum by using the method for recovering lithium according to one embodiment of the present invention.

  Although the embodiments and examples of the present invention have been described in detail as described above, it is apparent to those skilled in the art that many modifications can be made without departing substantially from the novel matters and effects of the present invention. It will be easy to understand. Accordingly, all such modifications are intended to be included within the scope of the present invention.

  For example, in the specification or the drawings, the terms described together with the broader or synonymous different terms at least once can be replaced with the different terms anywhere in the specification or the drawings. Further, the configuration and operation of the lithium recovery method are not limited to those described in the embodiments and examples of the present invention, and various modifications can be made.

S1 substitution process, S2 adsorption process, S3 elution process, S101 crystallization process, S102 separation process, S103 baking process, S104 water washing process

Claims (5)

A lithium recovery method for recovering lithium from manufacturing process waste water containing lithium and aluminum of positive electrode material for lithium secondary battery,
An adsorption step of bringing an ion exchange resin into contact with the waste water from the production process to selectively adsorb lithium ions to the ion exchange resin;
And e. Eluting the lithium ion from the ion exchange resin by bringing the aqueous solution containing a sodium salt into contact with the ion exchange resin to which the lithium ion is selectively adsorbed in the adsorption step;
The method for recovering lithium, wherein the ion exchange resin is a strongly acidic cation exchange resin having a sulfonic acid group or a functional group of its sodium salt type.   The method for recovering lithium according to claim 1, wherein the pH of the production process waste water in the adsorption step is set to 9 or more.   The lithium concentration of the said manufacturing process waste water in the said adsorption process is 0.3 g / L or more, The collection | recovery method of the lithium of Claim 1 or 2 characterized by the above-mentioned. Before the adsorption step, the method further comprises a substitution step of substituting a functional group contained in the ion exchange resin,
The method of recovering lithium according to any one of claims 1 to 3, wherein in the substitution step, the functional group is substituted from the sulfonic acid group to the sodium salt type.   The method for recovering lithium according to any one of claims 1 to 4, wherein the sodium salt in the elution step is sodium sulfate.

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