JP2012234732A - Lithium recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for selectively recovering only lithium from a lithium-containing solid in high yield with high economical efficiency resulting from minimization of waste.SOLUTION: The method for recovering lithium from a lithium-containing solid derived from a lithium-ion battery includes a step of leaching lithium from the lithium-containing solid with an acidic leaching solution in which a salt of a divalent or higher-valent metal is dissolved in an acid, to obtain a lithium recovery solution.

Description

  The present invention relates to a method for recovering lithium.

  Lithium is an alkali metal used as an electrolytic transfer medium for lithium secondary batteries. Lithium secondary batteries are well known as lightweight and high electric capacity batteries, and are used in large quantities as secondary batteries for various portable devices. In recent years, lithium secondary batteries are also used in hybrid cars and electric cars that have been developed to comply with carbon dioxide emission regulations. Many recycling technologies for lithium secondary batteries have been developed so far, but in many cases, recycling costs exceed the market price of recovered materials, and development of lower cost lithium recovery technologies is eagerly desired. Has been.

  As a technique that has been proposed so far, Japanese Patent No. 4581553 (Cited Document 1) discloses a method of recovering lithium from a lithium secondary battery by repeating solvent extraction. This method uses an organic solvent, so it is necessary to make the equipment explosion-proof, and it also costs money to prevent odors from the organic solvent, and the extraction operation must be repeated many times. The cost was high.

  Japanese Patent No. 4144820 (Cited Document 2) discloses a technique for recycling a positive electrode active material to a positive electrode active material raw material by dissolving the positive electrode active material with an acid and adding a lithium salt. This method can recycle lithium at a relatively low cost. However, in the past, lithium cobalt oxide has been used as the positive electrode active material for lithium ion secondary batteries, but in recent years, positive electrode active materials for lithium ion secondary batteries for vehicles have been cobalt acid for safety and cost reasons. In addition to lithium, lithium manganate, nickel nickelate, lithium iron phosphate, etc. have been diversified. For this reason, in order to recycle as a positive electrode active material material, a single type of positive electrode active material lithium secondary battery is selected for each of various positive electrode materials such as cobalt, nickel, manganese, and ternary. Each had to be handled individually.

  Furthermore, in Japanese Patent No. 3675392 (Cited document 3), metal is leached with an aqueous hydrochloric acid solution from coal ash containing metal and metal oxide obtained by baking and sieving of a lithium ion battery, and electrolysis is performed while adjusting pH. Thus, a technique is disclosed in which metallic copper and metallic cobalt are recovered, iron and aluminum are precipitated as hydroxides by raising the pH, and finally lithium is recovered as lithium carbonate precipitates. In this case, there is a concern that the economy will deteriorate because even metals with low market prices such as iron and aluminum are recovered.

  As a technique for selectively leaching lithium from a solid containing lithium and a transition metal, Japanese Patent No. 4492222 (Cited Document 4) proposes a method using oxalic acid. However, since oxalic acid is a relatively expensive acid and difficult to recover as leaching acid, there is a concern that the cost of leaching acid increases.

Japanese Patent No. 4581553 Japanese Patent No. 4144820 Japanese Patent No. 3675392 Japanese Patent No. 4492222

  The present invention has been made in view of such a conventional situation, and only lithium is selectively recovered from a lithium-containing solid in a high yield, and further, waste is minimized so that it can be recovered with high economic efficiency. It aims to provide a way to do.

  The present invention is as follows.

[1] The following steps:
Lithium is recovered from a lithium-containing solid derived from a lithium ion battery, including a step of leaching lithium from a lithium-containing solid with an acidic leachate in which a divalent or higher-valent metal salt is dissolved in an acid to obtain a lithium recovery solution. Method.

[2] The following steps:
A desalting step of obtaining a desalted solution by desalting lithium from the lithium recovery solution in an electrodialyzer comprising a combination of a monovalent selectively permeable cation exchange membrane and an anion exchange membrane, and the desalted solution The method according to [1], further comprising a desalting solution recycling step in which the salt is reused as the acidic leachate.

  [3] The concentration of the divalent or higher metal salt in the acidic leachate is 7000 ppm to 40,000 ppm when the divalent or higher metal is cobalt, and the divalent or higher metal is nickel. In the case of 7,000 ppm to 50,000 ppm, in the case where the divalent or higher metal is manganese, 7,000 ppm to 140,000 ppm, and in the case where the divalent or higher metal is iron, 7,000 ppm to 84000 ppm. [1] or [2].

  [4] A lithium recovery solution is obtained by leaching lithium with an acid from a lithium-containing solid, and the lithium recovery solution is contained in an electrodialyzer comprising a combination of a monovalent selectively permeable cation exchange membrane and an anion exchange membrane. In the desalting step of desalting lithium from the metal, a hydroxide and / or oxide of a divalent or higher metal and / or a reducing agent is added to the lithium recovery solution, and the pH of the lithium recovery solution is adjusted to 2-6. A method for recovering lithium, characterized in that electrodialysis is performed after adjustment.

  [5] The metal hydroxide and / or oxide having a valence of 2 or more is at least one metal compound selected from cobalt hydroxide, nickel hydroxide, iron hydroxide, and manganese oxide, according to [4]. the method of.

  [6] The method according to [4], wherein the reducing agent includes hydrogen peroxide or oxalic acid.

  [7] The method according to any one of [1] to [6], wherein the lithium recovery solution is purified by electrodialysis, and lithium hydroxide and an acid are recovered from the purified lithium solution by electrolysis. .

  [8] Lithium hydroxide is added to the purified lithium solution to adjust the pH of the solution to 7 to 13, and dissolved transition metals are precipitated as hydroxides. The method according to [7], wherein after separation of, metal components other than lithium in the solution are reduced with an ion exchange resin, and then lithium hydroxide and an acid are recovered by electrolysis.

  [9] The method according to [7] or [8], wherein the acid is sulfuric acid.

  [10] an anode chamber, a cathode chamber, and a salt chamber sandwiched between the anode chamber and the cathode chamber, the anode chamber and the salt chamber being separated by an anion exchange membrane, and the salt chamber and the salt chamber [9] The method according to [9], wherein an electrolytic apparatus in which the cathode chamber is isolated by a cation exchange membrane is used to generate lithium hydroxide in the cathode chamber and sulfuric acid in the anode chamber.

  [11] The pH according to [9] or [10], wherein the pH of the purified lithium solution is adjusted to 7 to 13 using the lithium hydroxide, and the sulfuric acid is used for regeneration of the ion exchange resin. Method.

  [12] The method according to any one of [1] to [11], wherein the lithium-containing solid is a lithium ion battery or a processed product thereof, or a solid discharged in a process of manufacturing a lithium ion battery.

  [13] The method according to any one of [1] to [12], wherein the divalent or higher valent metal is cobalt, nickel, manganese, and / or iron.

  According to the present invention, only lithium can be selectively recovered from a lithium-containing solid with a high yield, and further, by minimizing waste, it can be recovered with high economic efficiency.

An electrolysis apparatus comprising the anion exchange membrane and the cation exchange membrane of the present invention. A general electrolyzer consisting of a cation exchange membrane.

  The present invention relates to a method of appropriately performing lithium leaching, desalting and / or electrodialysis using a divalent or higher metal salt, hydroxide and / or oxide.

<Recovery of lithium>
In the lithium recovery method of the present invention, lithium is recovered from a lithium-containing solid derived from a lithium ion battery. This method includes a step of leaching lithium from a lithium-containing solid with an acidic leachate in which a divalent or higher metal salt is dissolved in an acid to obtain a lithium recovery solution.

  Examples of the lithium-containing solid include a lithium ion battery or a processed product thereof, or a solid discharged in the process of manufacturing a lithium ion battery. As the lithium-containing solid, a positive electrode active material or the like of a lithium ion secondary battery is preferable because it contains particles having a high lithium content.

  Lithium ion batteries deteriorated by use are usually baked at a temperature of 300 ° C. or higher, organic materials such as a binder are removed, and then crushed. Next, the copper current collector or the nickel electrode and the positive electrode active material containing a large amount of lithium can be separated from each other by sieving the pulverized product or sorting based on magnetic force.

  Further, according to this method, lithium can be recovered from a non-standard product discharged in the lithium ion battery positive electrode active material manufacturing process, a positive electrode active material recovered from a deteriorated lithium ion battery, or the like.

  Examples of the positive electrode active material of the lithium ion battery include many types such as lithium cobaltate, lithium nickelate, lithium manganate, ternary system containing cobalt, nickel and manganese, or lithium iron phosphate.

  According to this method, lithium can be recovered in a high yield from various lithium-containing solids as described above.

  In the present invention, when leaching lithium, an acidic aqueous solution containing divalent or higher metal ions is used (Example 1), and only an acid not containing divalent or higher metal ions is used (Comparative Example 2). ) Confirmed that lithium can be leached with less acid. Thereby, the amount of acid used for leaching can be suppressed, and the recovery cost can be reduced.

  Regarding the valence of metal ions, cobalt, nickel, and iron are divalent and trivalent, and manganese is divalent to a maximum of 7 valences. In the present invention, the valence of the metal ion is preferably from 2 to 7, more preferably from 2 to 4, more preferably from 2 or 3.

  The acidic leachate used for lithium recovery may be an acidic aqueous solution. Moreover, the metal salt more than bivalence contains cobalt, nickel, manganese, and / or iron as a metal more than bivalence. Further, the acid forming the acidic leachate may be either an inorganic acid or an organic acid. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid and the like. Examples of the organic acid include carboxylic acids such as formic acid, acetic acid, citric acid, and oxalic acid. In view of cost, work environment, and ease of metal recovery from the leachate, it is preferable to use sulfuric acid.

  When recovering lithium, a lithium recovery solution is obtained by leaching lithium from a lithium-containing solid using an acidic leachate in which a divalent or higher-valent metal salt is dissolved in an acid. By using an acidic leachate in which a divalent or higher metal salt is dissolved in an acid, lithium is leached at a high recovery rate while suppressing leaching of a metal that can be a divalent or higher metal ion contained in a lithium-containing solid. (See Example 2). Thereby, the amount of acid required for leaching can be suppressed.

  When recovering lithium, metals that can be divalent or higher-valent metal ions that have not been leached into the acid leachate liquid layer contain a large amount of expensive cobalt, nickel, etc. at the market price. If it contains a lot of relatively inexpensive metals such as iron and manganese, it may be turned to a crude steel raw material.

  The concentration of the divalent or higher metal salt in the acidic leachate during leaching varies depending on the metal species, but in the case of sulfate, cobalt is 7000 ppm to 40000 ppm, nickel is 7000 ppm to 50000 ppm, and manganese is 7000 ppm. It is preferable that it is above 140000 ppm and iron is 7000 ppm or more and 84000 ppm or less. If the concentration of the divalent or higher metal salt is within the above range, lithium is likely to leach out 100% (see Example 3 and Comparative Example 3).

  The reason why lithium can be efficiently leached when leached with an acidic aqueous solution in which divalent or higher-valent metal ions are dissolved is estimated as follows. That is, when a metal is leached out of a solid into an aqueous solution, a reaction in which the metal ion is stabilized in the aqueous solution by hydration proceeds in a non-equilibrium state. When present, the leaching of the same kind of metal is suppressed, and the leaching rate is slower than when the metal ion is not present. Therefore, lithium ions are not present in the aqueous solution, or the concentration thereof is low, so that the lithium ions are not affected by the metal ions already present in the aqueous solution, so that lithium is likely to be leached out.

<Reuse of desalted solution>
In the lithium recovery method of the present invention, it is preferable to reuse a desalted solution obtained by desalting lithium from a lithium recovered solution as an acidic leachate. Therefore, the present method can recover lithium in an electrodialyzer comprising a combination of a monovalent selectively permeable cation exchange membrane and an anion exchange membrane before or after the step of obtaining a lithium recovery solution or before the step of obtaining a lithium recovery solution. It is preferable to further include a desalting step of desalting lithium from the solution to obtain a desalting solution, and a desalting solution reusing step of reusing the desalting solution as an acidic leachate in the leachate providing step.

  In the desalting step, lithium is desalted from an leaching solution (lithium recovery solution) in which lithium has been leached by an electrodialyzer comprising a combination of a monovalent selectively permeable cation exchange membrane and an anion exchange membrane. Therefore, the metal contained in the lithium recovery solution is separated into bivalent or higher metal ions and lithium.

  The electrodialysis apparatus is an apparatus that can simultaneously perform desalting and concentration, and includes a cation exchange membrane and an anion exchange membrane. Electrodialysis is an operation in which desalting and concentration are performed simultaneously, and a cation exchange membrane and an anion exchange membrane are alternately arranged to form a multi-chamber electrodialysis tank. Thus, a desalted solution and a concentrated solution (for example, a lithium concentrated solution) can be obtained by moving a cation to the cathode side and an anion to the anode side.

  In the desalting step, it is preferable to use a monovalent selectively permeable cation exchange membrane as the cation exchange membrane of the electrodialysis apparatus. The monovalent selectively permeable cation exchange membrane is an exchange membrane that selectively permeates monovalent cations and separates divalent or higher metal ions and lithium ions (monovalent) contained in the lithium recovery solution. It is effective for.

  When electrodialysis is performed in the desalting step, the pH of the lithium recovery solution is 2.0 or more by adding a metal hydroxide and / or oxide having a valence of 2 or more or a reducing agent to the lithium recovery solution. 0.0 or less, preferably 2.5 or more and 6.0 or less, and more preferably 2.5 or more and 5.0 or less, thereby improving the current efficiency of lithium in electrodialysis and reducing the power cost of electrodialysis. Yes (see Example 5). When the pH of the lithium recovery solution is 2.0 or more, the hydrogen ion concentration is lowered, and the power consumption due to the movement of hydrogen is reduced, so that the current efficiency is increased. Further, when the pH of the lithium recovery solution is 6.0 or less, the metal hydroxide having a valence of 2 or more is not only difficult to precipitate but also difficult to adhere to an ion exchange membrane or the like. Therefore, current efficiency is improved and the useful life of the ion exchange membrane is extended.

  Examples of the bivalent or higher metal hydroxide and / or oxide include cobalt hydroxide, nickel hydroxide, iron hydroxide, and manganese oxide.

  The residue from which lithium is selectively leached contains an oxide of a metal having a valence of 2 or more. However, this oxide is not dissolved only by an acid, so it is reduced and dissolved by adding a reducing agent. It becomes easy to do. Therefore, the acid is consumed by dissolving the divalent or higher metal, and the pH of the lithium recovery solution increases. As the reducing agent, hydrogen peroxide, oxalic acid or the like is preferably used.

  When adjusting the pH by adding a metal hydroxide having a valence of 2 or more and / or a metal oxide having a valence of 2 or more, or a reducing agent, even if the concentration of a metal ion having a valence of 2 or more is increased, The metal ion does not permeate the monovalent selectively permeable cation exchange membrane, so the current efficiency does not decrease. However, when a monovalent cation such as ammonia is added, the metal ion permeates the monovalent selectively permeable cation exchange membrane. It was found that the current efficiency of lithium concentration was reduced (see Comparative Example 4).

  When electrodialysis is performed, it is preferable to use a diluted lithium salt for the initial concentrated solution because the electrical resistance at the initial stage of electrodialysis is reduced and the current efficiency is increased. Furthermore, by reducing the ratio of the concentration treatment liquid to the initial desalination treatment liquid, it is possible to make the concentration concentration at the end higher than the initial concentration of lithium desalination liquid.

  The desalting solution contains divalent or higher metal ions separated from each other by an electrodialysis apparatus in which lithium is desalted and a monovalent selectively permeable cation exchange membrane and an anion exchange membrane are combined. In the desalting solution reuse step, an acid is added to the desalting solution generated by electrodialysis to adjust the pH of the desalting solution to a range of 0 to 1.0, preferably to a range of pH 0 to 0.5. Can be used as an acidic leachate. The acid used for pH adjustment in the desalting solution recycling step may be an acid as described above. The desalting solution reuse step eliminates the need to treat the desalting solution as a waste solution, thereby minimizing the cost of waste solution treatment.

  On the other hand, in the concentrated lithium solution separated and purified by electrodialysis in the desalting step, a trace amount of divalent or higher-valent metal ions that have passed through the monovalent selective permeation cation exchange membrane exists. This trace amount of divalent or higher-valent metal ions is deposited as a hydroxide on the surface or inside of the electrolytic membrane in the electrolytic process for recovering lithium hydroxide, thereby reducing the current efficiency of electrolysis or shortening the lifetime of the electrolytic membrane. There is a fear.

  During or after the desalting step, by adding lithium hydroxide to a lithium concentrated solution (for example, a lithium solution purified by electrodialysis) containing a trace amount of metal ions having a valence of 2 or more, the concentrated solution is moved to the concentrated solution side. The leaked divalent or higher valent metal ions can be precipitated as hydroxides and separated into individual liquids. Accordingly, lithium hydroxide is added to the purified lithium solution to adjust the pH to 7 to 13, and dissolved transition metal (for example, the divalent or higher metal) is precipitated as a hydroxide. After separating the hydroxide from the above, it is preferable to reduce metal components other than lithium in the solution with an ion exchange resin, and then recover lithium hydroxide and sulfuric acid by electrolysis.

  The pH of the lithium concentrate for precipitating divalent or higher valent metal ions from the lithium concentrate as a hydroxide is 7 or more and 13 or less, preferably 8 or more and 11 or less. This pH adjustment is performed by adding lithium hydroxide to the lithium concentrate. When the pH of the lithium concentrate is 7 or more, metal ions having a valence of 2 or more are sufficiently precipitated, and a small amount of adsorbent for post-purification is sufficient, so that the purification efficiency is good. Moreover, when the pH of the lithium concentrate is 13 or less, lithium hydroxide is not used excessively after the deposition of divalent or higher-valent metal ions, which is highly economical. Moreover, the metal hydroxide separated in this way can be used as a pH adjuster when electrodialysis is performed.

  The purified lithium solution from which the hydroxide has been separated can be further purified by an adsorbent such as an ion exchange resin or activated carbon. As the adsorbent used for purification, chelate ion exchange resins such as polyamine chelate resins, amidooxime chelate resins, aminocarboxylic acid chelate resins, etc. select metal ions having a valence of 2 or more in a high concentration lithium salt solution. It is preferable because it adsorbs chemically.

  Preferred ion exchange resins include Diaion CR-20 manufactured by Mitsubishi Chemical Corporation, Sumichel MC900, Sumichel MC850, and Sumichel MC600 manufactured by Sumika Chemtex Co., Ltd.

  The lithium solution purified as described above can be decomposed into lithium hydroxide and acid by electrolysis, and lithium hydroxide can be recovered. The acid recovered by electrolysis may be the acid described above, in particular sulfuric acid.

  When sulfuric acid is used as the acid for forming the acidic leachate, the electrolysis apparatus includes, or includes, an anode chamber, a cathode chamber, and a salt chamber sandwiched between the anode chamber and the cathode chamber, and an anode chamber. It is possible to use an electrolysis apparatus (FIG. 1) in which the salt chamber is isolated by an anion exchange membrane and the salt chamber and the cathode chamber are isolated by a cation exchange membrane. By using this apparatus, lithium hydroxide is easily generated in the cathode chamber and sulfuric acid is easily generated in the anode chamber.

  When sulfuric acid is used as an acid for forming the acidic leachate, if an electrolytic cell in which the anode and the cathode are separated by a cation exchange membrane (cation exchange membrane) as shown in FIG. 2 is used, the pH of the anode chamber is reduced by electrolysis. There is a concern that the current efficiency decreases due to the decrease (see Comparative Example 5).

  The electrolysis can be performed at an electrolysis temperature of 0 to 90 ° C.

  As a cathode during electrolysis, an electrode obtained by applying nickel oxide as a catalyst to nickel expanded metal can be used. Further, as the anode, an electrode in which ruthenium, iridium, or titanium is applied as a catalyst to an expanded metal of titanium can be used.

  The cation exchange membrane used for electrolysis is a membrane that can pass lithium ions, and is a membrane made of a polymer having at least one sulfonic acid group, carboxylic acid group, phosphonic acid group, sulfate ester group, or phosphate ester group. Can be used.

  The anion exchange membrane used for electrolysis is a membrane made of a polymer having a strong basic group such as a quaternary ammonium group, or a weakly basic such as a primary amino group, a secondary amino group, or a tertiary amino group. A film made of a polymer having a functional group can be used.

  The acid (for example, sulfuric acid) produced at the same time as lithium hydroxide during electrolysis can be used to regenerate the ion exchange resin used for purification. When used for regeneration of an ion exchange resin, it can be adjusted to a desired concentration with water and / or a high concentration acid.

  Furthermore, the acid generated by electrolysis or the acid used to regenerate the ion exchange resin can be used for adjusting the acidic leachate.

  In addition, the lithium salt solution whose concentration has been reduced by electrolysis can be used as an initial concentrated solution for electrodialysis by adjusting the concentration by further dilution or the like.

  Similarly, when the lithium-containing solid is lithium manganate or lithium iron phosphate, lithium can be recovered with an excellent yield (see Examples 11 to 25).

  Even if the lithium-containing solid is obtained by treating a lithium ion secondary battery, the recovery system of the present invention can recover lithium with an excellent yield (see Example 26).

  As described above, the lithium recovery system according to the present invention selectively recovers only lithium from a lithium-containing solid such as a lithium ion secondary battery processed product in a high yield, and further minimizes waste, Lithium can be recovered with high economic efficiency while considering the environment.

  Next, the present invention will be described more specifically based on examples, but the present invention is not limited to the examples.

[analysis]
-PH measurement It measured at 25 degreeC using HM-20P (made by Toa DKK Corporation).
-Analysis of metal ion concentration in aqueous solution When the ion concentration was 1 ppm or more, it was measured by inductively coupled plasma (ICP) emission analysis.
When the ion concentration was less than 1 ppm, it was measured by ICP-mass spectrometry (MAS).
・ Leaching rate (%)
Following formula:
Leaching rate (%) = {(Absolute amount of metal in recovered liquid after leaching treatment) / (Absolute amount of metal in solid)}
Calculated according to

[When the active material is ternary]
[Experiment 1] (First leaching)
In a 2000 ml Erlenmeyer flask, 1520 g of 1M sulfuric acid (manufactured by Wako Pure Chemical Industries, Ltd.) is added, heated to 80 ° C. in a water bath, and stirred with a stirrer. To this, 80 g of ternary active material cell seed NMC (manufactured by Nippon Chemical Industry Co., Ltd.) was added and stirred for 3 hours to leach lithium, cobalt, nickel and manganese. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm.

<Example 1> (Leaching with desalting solution)
Lithium sulfate was desalted from 1000 ml of the leachate of Experimental Example 1 using an electrodialysis apparatus (acylator EX3B, manufactured by Astom Co., Ltd.) comprising an anion exchange membrane and a cation exchange membrane. The recovered solution was 1000 ml of pure water, the anion exchange membrane was Neocepta AMX (manufactured by Astom Co., Ltd.), and the cation exchange membrane was monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.), voltage 10 V, temperature 25 Electrodialysis was performed at 0 ° C. The analysis of the concentration of the metal ions in 1200 ml of the recovered liquid revealed lithium 3400 ppm, cobalt 500 ppm, nickel 510 ppm, and manganese 0.4 ppm. Nickel, 6940 ppm and manganese, 1 ppm.

  Next, metal ions were leached from the active material using this desalting solution. First, sulfuric acid was added to the desalted solution to bring the pH to zero. The sulfuric acid concentration at this time was 0.4M. 760 g of this liquid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. To this, 40 g of a ternary active material was added and stirred for 3 hours to leach out lithium, cobalt, nickel and manganese. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 2> (Leaching with a saturated salt solution)
Desalting and leaching were repeated until the sulfates of cobalt, nickel, and manganese were saturated. The concentration of each metal ion at this time was lithium 1000 ppm, cobalt 40000 ppm, nickel 50000 ppm, and manganese 70000 ppm. Metal ions were leached from the active material in the same manner as in Example 1 except that this saturated solution was used as the leaching solution. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

<Comparative Example 1>
The metal ion concentration of the leachate prepared in Experimental Example 1 was analyzed. The analysis results are shown in Table 1.

<Comparative example 2>
Metal ions of the active material were leached in the same manner as in Experimental Example 1 except that the sulfuric acid concentration of the leaching solution was 0.4M. The results of analyzing the metal ion concentration of the leachate are shown in Table 1.

<Example 3> (Salt concentration and leaching rate 1)
Sulfuric acid was added to 1000 ml of a salt solution in which 10% cobalt sulfate and 10% nickel sulfate were dissolved to bring the pH to zero. The sulfuric acid concentration at this time was 0.4M. 760 g of this liquid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. To this, 40 g of a ternary active material was added and stirred for 3 hours to leach out lithium, cobalt, nickel and manganese. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 4> (Salt concentration and leaching rate 2)
Metal ions were leached from the active material in the same manner as in Example 3 except that a salt solution in which 2% cobalt sulfate and 2% nickel sulfate were dissolved was used. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 5> (pH adjustment 1 after leaching)
Add 850 g of 1.5 M sulfuric acid to a 1000 ml Erlenmeyer flask, heat to 80 ° C. with a water bath, and stir with a stirrer. To this, 150 g of a ternary active material was added and stirred for 3 hours to leach lithium, cobalt, nickel, and manganese. The pH of the leachate was measured to be 1.7, and the metal ion concentrations were lithium 12400 ppm, cobalt 19700 ppm, nickel 19800 ppm, and manganese 1900 ppm. When 2.38 g of nickel hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto and stirred at 80 ° C. for 2 hours, the pH was 2.62. Thereafter, the mixture was allowed to stand, the supernatant was taken out, and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

  Next, about 500 ml of the leachate, lithium sulfate was desalted using an electrodialyzer comprising an anion exchange membrane and a cation exchange membrane (Acylizer EX3B, manufactured by Astom Co., Ltd.). 500 ml of pure water is used as the recovery liquid, Neocepta AMX (manufactured by Astom Co., Ltd.) is used as the anion exchange membrane, and monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.) is used as the cation exchange membrane. Electrodialysis was performed at a temperature of 25 ° C. Analysis of the concentration of the metal ions in 550 ml of the collected liquid revealed lithium 10280 ppm, cobalt 1610 ppm, nickel 1770 ppm, manganese 150 ppm, and the current efficiency at this time was 76%.

<Example 6> (pH adjustment 2 after leaching)
The pH was adjusted by leaching metal ions from the active material in the same manner as in Example 5 except that 0.65 g of manganese oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was used for pH adjustment after leaching. The pH after adjustment was 2.77. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

  Next, electrodialysis was performed on 500 ml of the leachate in the same manner as in Example 5. Analysis of the concentration of the metal ions in 550 ml of the recovered liquid revealed lithium 10770 ppm, cobalt 1610 ppm, nickel 1620 ppm, and manganese 350 ppm, and the current efficiency at this time was 80%.

<Example 7> (pH adjustment 3 after leaching)
The pH was adjusted by leaching metal ions from the active material in the same manner as in Example 5 except that 10 g of 30% hydrogen peroxide water (manufactured by Wako Pure Chemical Industries, Ltd.) was used for pH adjustment after leaching. . The pH after adjustment was 2.83. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

  Next, electrodialysis was performed on 500 ml of the leachate in the same manner as in Example 5. When 550 ml of the recovered liquid was analyzed for the concentration of the metal ions, it was found to be 11000 ppm for lithium, 1740 ppm for cobalt, 1780 ppm for nickel, and 250 ppm for manganese. The current efficiency at this time was 85%.

<Comparative Example 3>
In the same manner as in Example 5, metal ions were leached from the ternary active material, and 2.88 g of 10% ammonia water was added to adjust the pH. The pH was 2.66.

  Next, electrodialysis was performed on 500 ml of the leachate in the same manner as in Example 5. Analysis of the concentration of the metal ions in 550 ml of the recovered liquid revealed lithium 10600 ppm, cobalt 1610 ppm, nickel 1620 ppm, and manganese 160 ppm, and the current efficiency at this time was 45%.

<Example 8> (Purification 1 with ion exchange resin)
30.6 ml of 2M lithium hydroxide was added to 500 ml of the recovered liquid obtained in Example 5, and the pH was adjusted to 8, whereby transition metal ions were precipitated as hydroxides. The composition of the metal ions in the filtrate after filtering the precipitate was lithium 9250 ppm, cobalt 122 ppm, nickel 43 ppm, and manganese 4 ppm.

  Next, the transition metal was further removed to a low concentration by an ion exchange resin. The column was filled with 530 cc of ion-exchange resin Sumichel MC900 (manufactured by Sumika Chemtex Co., Ltd.) together with distilled water and passed through at a rate of 10 ml / min to remove transition metals. The composition of the metal ions after purification was 9160 ppm lithium, less than 0.5 ppb cobalt, less than 5 ppb nickel, and less than 1 ppb manganese.

<Example 9> (Purification 2 with ion exchange resin)
The recovered liquid obtained in Example 6 was purified in the same manner as in Example 8 except that transition metal ions were precipitated at pH 10 and Diaion CR20 (Mitsubishi Chemical Corporation) was used as the ion exchange resin. did. The composition of metal ions after precipitation filtration was less than 9240 ppm lithium, 120 ppb cobalt, 35 ppb nickel, and 1 ppb manganese. Moreover, the composition of the metal ion after the ion exchange resin purification was lithium 9150 ppm, cobalt less than 0.5 ppb, nickel less than 5 ppb, and manganese less than 1 ppb.

<Example 10> (Production of lithium hydroxide by electrolysis)
Electrolysis was performed on the liquid purified with the ion exchange resin in Example 8. The configuration of the electrolyzer used is shown in FIG. Asciplex F2205D manufactured by Asahi Kasei Chemicals Corporation was used as the fluorine-based cation exchange membrane, and Neoceptor AMX manufactured by Astom Co., Ltd. was used as the anion exchange membrane. In both cases, the effective membrane area was 25.5 cm ² . As the cathode, an electrode obtained by applying nickel oxide as a catalyst to nickel expanded metal was used. As the anode, an electrode in which ruthenium, iridium, and titanium were applied as catalysts to titanium expanded metal was used. A power supply unit is made so that 500 ml of purified liquid in the salt chamber, 300 ml of 11% lithium hydroxide aqueous solution in the cathode chamber, and 300 ml of 10% sulfuric acid in the anode chamber are passed at 60 ° C., respectively, and the current density is 0.2 A / cm ^2. The voltage was applied with PK36-11 (manufactured by Matsusada Precision Co., Ltd.). The voltage was 50V. This electrolysis recovered 330 ml of 14.6% lithium hydroxide from the cathode compartment and 330 ml of 18.3% sulfuric acid from the anode compartment. The pH of the salt chamber liquid was 8 and the current efficiency was 81%.

<Comparative example 4>
For the liquid purified with the ion exchange resin, electrolysis was performed in the same manner as in Example 10 except that the purified liquid was passed through the anode chamber using the electrolysis apparatus having the configuration shown in FIG. 550 ml of 4% lithium hydroxide was recovered. The pH of the salt chamber was 8 at the start of electrolysis, 0.1 at the end, and the current efficiency was 48%.

[When the active material is lithium manganate]
[Experiment 2] (First leaching)
In a 2000 ml Erlenmeyer flask, 1520 g of 2M sulfuric acid (manufactured by Wako Pure Chemical Industries, Ltd.) is added, heated to 80 ° C. with a water bath, and stirred with a stirrer. To this, 80 g of lithium manganate (JGC Catalysts & Chemicals Co., Ltd.) was added, and stirred for 3 hours to leach lithium and manganese. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm.

<Example 11> (Leaching with desalting solution)
Lithium sulfate was desalted from 1000 ml of the leachate of Experimental Example 2 using an electrodialysis apparatus (acylator EX3B, manufactured by Astom Co., Ltd.) comprising an anion exchange membrane and a cation exchange membrane. The recovered solution was 1000 ml of pure water, the anion exchange membrane was Neocepta AMX (manufactured by Astom Co., Ltd.), and the cation exchange membrane was monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.), voltage 10 V, temperature 25 Electrodialysis was performed at 0 ° C. Analysis of the concentration of the metal ions in 1100 ml of the recovered liquid revealed that lithium was 1730 ppm and manganese was 580 ppm. In the 900 ml desalted liquid, the composition of the metal ions was 110 ppm lithium and 7160 ppm manganese.

  Next, metal ions were leached from the active material using this desalting solution. First, sulfuric acid was added to the desalted solution to bring the pH to zero. The sulfuric acid concentration at this time was 0.4M. 760 g of this liquid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. The active material 40g was thrown into this, and it stirred for 3 hours, and leached lithium and manganese. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 2 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 12> (Leaching with a saturated salt solution)
Desalting and leaching were repeated until the manganese sulfate was saturated. At this time, the concentration of lithium was 1000 ppm and the concentration of manganese was 140000 ppm. Metal ions were leached from the active material in the same manner as in Example 11 except that this saturated solution was used as the leaching solution. Table 2 shows the results of analyzing the concentration of metal ions in the leachate.

<Comparative Example 5>
The metal ion concentration of the leachate prepared in Experimental Example 2 was analyzed. The analysis results are shown in Table 2.

<Comparative Example 6>
The active material metal ions were leached in the same manner as in Experimental Example 2 except that the sulfuric acid concentration of the leaching solution was 0.4M. Table 2 shows the result of analyzing the metal ion concentration of the leachate.

<Example 13> (Salt concentration and leaching rate 1)
Sulfuric acid was added to 1000 ml of a salt solution in which 10% manganese sulfate was dissolved to bring the pH to zero. The sulfuric acid concentration at this time was 0.4M. 760 g of this liquid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. To this was added 40 g of lithium manganate, and the mixture was stirred for 3 hours to leach lithium and manganese. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 2 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 14> (Salt concentration and leaching rate 2)
Metal ions were leached from the active material in the same manner as in Example 13 except that a salt solution in which 2% of manganese sulfate was dissolved was used. Table 2 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 15> (pH adjustment 1 after leaching)
Add 850 g of 1.5 M sulfuric acid to a 1000 ml Erlenmeyer flask, heat to 80 ° C. with a water bath, and stir with a stirrer. To this was added 150 g of lithium manganate, and the mixture was stirred for 3 hours to leach lithium and manganese. The pH of the leachate was measured and found to be 1.37, and the metal ion concentration was 6700 ppm of lithium and 24,000 ppm of manganese. When 3.87 g of manganese oxide was added thereto and stirred at 80 ° C. for 2 hours, the pH was 2.61. Thereafter, the mixture was allowed to stand, the supernatant was taken out, and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 2 shows the results of analyzing the concentration of metal ions in the leachate.

  Next, lithium sulfate was desalted from 500 ml of this leachate using an electrodialysis apparatus (acylator EX3B, manufactured by Astom Co., Ltd.) comprising an anion exchange membrane and a cation exchange membrane. Using 500 ml of pure water as the recovery liquid, using Neocepta AMX (manufactured by Astom Co., Ltd.) as the anion exchange membrane, using monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.) as the cation exchange membrane, voltage 10 V, Electrodialysis was performed at a temperature of 25 ° C. When 550 ml of the collected liquid was analyzed for the concentration of the metal ions, it was 5720 ppm for lithium and 2350 ppm for manganese, and the current efficiency at this time was 75%.

<Example 16> (pH adjustment 2 after leaching)
The pH was adjusted by leaching metal ions from the active material in the same manner as in Example 15 except that 22 g of 30% aqueous hydrogen peroxide was used for pH adjustment after leaching. The pH after adjustment was 2.94. Table 2 shows the results of analyzing the concentration of metal ions in the leachate.

  Next, 500 ml of this leachate was electrodialyzed in the same manner as in Example 15. When 550 ml of the collected liquid was analyzed for the concentration of metal ions, it was 5440 ppm for lithium and 2320 ppm for manganese, and the current efficiency at this time was 86%.

<Comparative Example 7>
In the same manner as in Example 15, metal ions were leached from the active material, and pH was adjusted by adding 6.17 g of 10% aqueous ammonia. The pH was 2.62.

  Next, 500 ml of this leachate was electrodialyzed in the same manner as in Example 15. When 550 ml of the collected liquid was analyzed for the concentration of metal ions, it was 5600 ppm for lithium and 2180 ppm for manganese, and the current efficiency at this time was 43%.

<Example 17> (Purification with ion exchange resin)
To 500 ml of the recovered liquid obtained in Example 15, 21.9 ml of 2M lithium hydroxide was added to adjust its pH to 8, and transition metal ions were precipitated as hydroxides. The composition of metal ions in the filtrate after filtering the precipitate was lithium 5150 ppm and manganese 4 ppm.

  Next, the transition metal was further removed to a low concentration by an ion exchange resin. The column was filled with 520 cc of ion-exchange resin Sumichel MC900 (manufactured by Sumika Chemtex Co., Ltd.) together with distilled water and passed through at a rate of 10 ml / min to remove transition metals. The composition of the metal ion after purification was lithium 5100 ppm and manganese less than 1 ppb.

<Example 18> (Production of lithium hydroxide by electrolysis)
The liquid purified with the ion exchange resin in Example 17 was electrolyzed. The configuration of the electrolyzer used is shown in FIG. Asciplex F2205D manufactured by Asahi Kasei Chemicals Corporation was used as the fluorine-based cation exchange membrane, and Neoceptor AMX manufactured by Astom Co., Ltd. was used as the anion exchange membrane. In both cases, the effective membrane area was 25.5 cm ² . As the cathode, an electrode in which nickel oxide was applied as a catalyst to nickel expanded metal was used. As the anode, an electrode in which ruthenium, iridium and titanium were applied as a catalyst to an expanded metal of titanium was used. Liquid 500ml purified salt chamber, 13% aqueous lithium hydroxide 300ml the cathode chamber, and liquid permeation of 10% sulfuric acid 300ml at 60 ° C. respectively to the anode chamber, the power supply such that the current density is 0.2 A / cm ² The voltage was applied with PK36-11 (manufactured by Matsusada Precision Co., Ltd.). The voltage was 50V. This electrolysis recovered 330 ml of 14.4% lithium hydroxide from the cathode compartment and 330 ml of 19.2% sulfuric acid from the anode compartment. The pH of the salt chamber solution was unchanged at 8, and the current efficiency was 88%.

<Comparative Example 8>
The liquid purified with the ion exchange resin was electrolyzed in the same manner as in Example 18 except that the purified liquid was passed through the anode chamber using the electrolysis apparatus having the configuration shown in FIG. . Collected 330 ml of 2% lithium hydroxide. The pH of the salt chamber was 8 at the start of electrolysis, 0.1 at the end, and the current efficiency was 41%.

[When the active material is lithium iron phosphate]
[Experiment 3] (First leaching)
In a 2000 ml Erlenmeyer flask, 1520 g of 1M sulfuric acid (manufactured by Wako Pure Chemical Industries, Ltd.) is added, heated to 80 ° C. in a water bath, and stirred with a stirrer. To this, 80 g of lithium iron phosphate (made by Formasa Energy & Material Tech.) Was added and stirred for 3 hours to leach out lithium and iron. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm.

<Example 19> (Leaching with desalting solution)
Lithium sulfate was desalted from 1000 ml of the leachate of Experimental Example 3 using an electrodialysis apparatus (acylator EX3B, manufactured by Astom Co., Ltd.) comprising an anion exchange membrane and a cation exchange membrane. Using 1000 ml of pure water as the recovered liquid, using Neocepta AMX (manufactured by Astom Co., Ltd.) as the anion exchange membrane, using monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.) as the cation exchange membrane, voltage 10 V, Electrodialysis was performed at a temperature of 25 ° C. Analysis of the concentration of the metal ions in 1100 ml of the recovered liquid revealed that lithium was 2200 ppm and iron was 1660 ppm. In the 900 ml of desalted liquid, the composition of the metal ions was 200 ppm lithium and 18100 ppm iron.

  Next, metal ions were leached from the active material using this desalting solution. First, sulfuric acid was added to the desalted solution to adjust the pH to zero. The sulfuric acid concentration at this time was 0.4M. 760 g of this liquid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. To this was added 40 g of lithium iron phosphate, and the mixture was stirred for 3 hours to leach lithium and iron. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 3 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 20> (Leaching with a saturated salt solution)
Desalting and leaching were repeated until the iron sulfate was saturated. At this time, the concentration of lithium ions was 1000 ppm, and the concentration of iron ions was 84000 ppm. Metal ions were leached from the active material in the same manner as in Example 19 except that this saturated solution was used as the leaching solution. Table 3 shows the results of analyzing the concentration of metal ions in the leachate.

<Comparative Example 9>
The metal ion concentration of the leachate prepared in Experimental Example 3 was analyzed. The analysis results are shown in Table 3.

<Comparative Example 10>
The active material metal ions were leached in the same manner as in Experimental Example 3 except that the sulfuric acid concentration of the leaching solution was 0.4M. Table 3 shows the result of analyzing the metal ion concentration of the leachate.

<Example 21> (Salt concentration and leaching rate 1)
Sulfuric acid was added to 1000 ml of a salt solution in which 10% of iron sulfate was dissolved to bring the pH to zero. The sulfuric acid concentration at this time was 0.4M. 760 g of this liquid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. To this was added 40 g of lithium iron phosphate, and the mixture was stirred for 3 hours to leach lithium and iron. The supernatant was taken out and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 3 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 22> (Salt concentration and leaching rate 2)
Metal ions were leached from the active material in the same manner as in Example 21 except that a salt solution in which 2% of iron sulfate was dissolved was used. Table 3 shows the results of analyzing the concentration of metal ions in the leachate.

<Example 23> (pH adjustment after leaching)
Add 850 g of 1.5 M sulfuric acid to a 1000 ml Erlenmeyer flask, heat to 80 ° C. with a water bath, and stir with a stirrer. To this was added 150 g of lithium iron phosphate, and the mixture was stirred for 3 hours to leach lithium and iron. The pH of the leachate was measured and found to be 0.98. When 9.48 g of manganese oxide was added thereto and stirred at 80 ° C. for 2 hours, the pH became 2.72. Thereafter, the mixture was allowed to stand to take out the supernatant, and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 3 shows the results of analyzing the concentrations of lithium ions and iron ions in the leachate.

  Next, lithium sulfate was desalted from 500 ml of the leachate using an electrodialysis apparatus (acylator EX3B, manufactured by Astom Co., Ltd.) comprising an anion exchange membrane and a cation exchange membrane. Using 500 ml of pure water as the recovery liquid, using Neocepta AMX (manufactured by Astom Co., Ltd.) as the anion exchange membrane, using monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.) as the cation exchange membrane, voltage 10 V, Electrodialysis was performed at a temperature of 25 ° C. When 550 ml of the collected liquid was analyzed for the concentration of the metal ions, it was 7360 ppm for lithium and 5570 ppm for iron, and the current efficiency at this time was 78%.

<Comparative Example 11>
In the same manner as in Example 23, metal ions were leached from the active material, and pH was adjusted by adding 15.1 g of 10% aqueous ammonia. The pH was 2.71.

  Next, electrodialysis was performed on 500 ml of the leachate in the same manner as in Example 23. When 550 ml of the collected liquid was analyzed for the concentration of the metal ions, it was lithium 7440 ppm and iron 5570 ppm, and the current efficiency at this time was 39%.

<Example 24> (Purification with ion exchange resin)
To 500 ml of the recovered liquid obtained in Example 23, 50.2 ml of 2M lithium hydroxide was added to adjust the pH to 8, and transition metal ions were precipitated as hydroxides. The composition of the metal ions in the filtrate after filtering the precipitate was 5010 ppm lithium and 83 ppm iron.

  Next, the transition metal was further removed to a low concentration by an ion exchange resin. The column was filled with 550 cc of ion-exchange resin Sumichel MC900 (manufactured by Sumika Chemtex Co., Ltd.) together with distilled water and passed through at a rate of 10 ml / min to remove transition metals. The composition of the metal ions after purification was 4960 ppm of lithium and less than 5 ppb of iron.

<Example 25> (Production of lithium hydroxide by electrolysis)
Electrolysis was carried out on the liquid purified with the ion exchange resin in Example 24. The configuration of the electrolyzer used is shown in FIG. Asciplex F2205D manufactured by Asahi Kasei Chemicals Corporation was used as the fluorine-based cation exchange membrane, and Neoceptor AMX manufactured by Astom Co., Ltd. was used as the anion exchange membrane. In both cases, the effective membrane area was 25.5 cm ² . As the cathode, an electrode in which nickel oxide was applied as a catalyst to nickel expanded metal was used. As the anode, an electrode in which ruthenium, iridium, and titanium were applied as catalysts to titanium expanded metal was used. Liquid 500ml purified salt chamber, 13% aqueous lithium hydroxide 300ml the cathode chamber, and liquid permeation of 10% sulfuric acid 300ml at 60 ° C. respectively to the anode chamber, the power supply such that the current density is 0.2 A / cm ² The voltage was applied with PK36-11 (manufactured by Matsusada Precision Co., Ltd.). The voltage was 50V. This electrolysis recovered 330 ml of 14.3% lithium hydroxide from the cathode compartment and 330 ml of 14.2% sulfuric acid from the anode compartment. The pH of the salt chamber solution was unchanged at 8, and the current efficiency was 82%.

<Comparative Example 12>
The liquid purified with the ion exchange resin was electrolyzed in the same manner as in Example 25 except that the purified liquid was passed through the anode chamber using the electrolysis apparatus having the configuration shown in FIG. . Collected 330 ml of 1% lithium hydroxide. The pH of the salt chamber was 8 at the start of electrolysis, 0.1 at the end, and the current efficiency was 47%.

<Example 26> (Recovery of lithium from used lithium ion secondary battery)
Five used lithium ion secondary batteries (cylindrical can type 18650) were baked at 700 ° C. for 2 hours in a muffle furnace, and the contents were taken out by peeling off the exterior. This was chopped to about 2 mm square with a cutting machine, pulverized with a ball mill for 2 hours, and passed through a 150 mesh sieve to obtain 50 g of powder containing the active material.

  Sulfuric acid was added to 1000 ml of a salt solution in which 2% cobalt sulfate and 2% nickel sulfate were dissolved to bring the pH to zero. The sulfuric acid concentration at this time was 0.4M. 950 g of this liquid is placed in a 1000 ml Erlenmeyer flask, heated to 80 ° C. with a water bath, and stirred with a stirrer. 50 g of powder was put into this and stirred for 3 hours to leach lithium and transition metals. 1 g of the leaching residue was taken out, placed in a mixed solution of 10 ml of 5M sulfuric acid and 1 ml of 30% hydrogen peroxide solution, stirred at 80 ° C. for 3 hours and filtered, and the filtrate was analyzed for metal ions, and lithium was not detected. .

  The pH of the leachate was measured and found to be 1.8. When 1.87 g of nickel hydroxide was added thereto and stirred at 80 ° C. for 2 hours, the pH became 2.78. Thereafter, the mixture was allowed to stand to take out the supernatant, and the undissolved material was separated. The extracted leachate was filtered with a filter having a pore size of 0.45 μm. Table 1 shows the results of analyzing the concentration of metal ions in the leachate. In addition to the metal contained in the positive electrode shown in Table 1, the lithium battery uses aluminum or copper as a current collector, and the leachate from the waste lithium battery contains these ions.

  Next, lithium sulfate was desalted from 950 ml of this leachate using an electrodialysis apparatus (acylator EX3B, manufactured by Astom Co., Ltd.) comprising an anion exchange membrane and a cation exchange membrane. 950 ml of pure water was used as the recovery liquid, Neocepta AMX (manufactured by Astom Co., Ltd.) was used as the anion exchange membrane, and monovalent selective membrane Neocepta CIMS (manufactured by Astom Co., Ltd.) was used as the cation exchange membrane. Electrodialysis was performed at 0 ° C. When 1050 ml of the collected liquid was analyzed for the concentration of the metal ions, it was lithium 3260 ppm, cobalt 760 ppm, nickel 800 ppm, and manganese 50 ppm, and the current efficiency at this time was 79%.

  Next, transition metals were removed from the recovered liquid with an ion exchange resin. 29.6 ml of 2M lithium hydroxide was added to 1050 ml of the collected liquid to adjust its pH to 8, and transition metal ions were precipitated as hydroxides. The composition of the metal ions in the filtrate after filtering the precipitate was lithium 2930 ppm, cobalt 122 ppm, nickel 43 ppm, and manganese 4 ppm.

  Next, the transition metal was further removed to a low concentration by an ion exchange resin. 960 cc of ion exchange resin Sumichel MC900 (manufactured by Sumika Chemtex Co., Ltd.) was packed in a column together with distilled water, and passed through at a rate of 10 ml / min to remove transition metals. The composition of the metal ions after purification was lithium 2900 ppm, cobalt less than 0.5 ppb, nickel less than 5 ppb, and manganese less than 1 ppb.

Next, electrolysis was performed on the liquid purified with the ion exchange resin. The configuration of the electrolyzer used is shown in FIG. Asciplex F2205D manufactured by Asahi Kasei Chemicals Corporation was used as the fluorine-based cation exchange membrane, and Neoceptor AMX manufactured by Astom Co., Ltd. was used as the anion exchange membrane. In both cases, the effective membrane area was 25.5 cm ² . As the cathode, an electrode obtained by applying nickel oxide as a catalyst to nickel expanded metal was used. As the anode, an electrode in which ruthenium, iridium, and titanium were applied as catalysts to titanium expanded metal was used. 960 ml of purified liquid in the salt chamber, 300 ml of 13% lithium hydroxide aqueous solution in the cathode chamber, and 300 ml of 10% sulfuric acid in the anode chamber at 60 ° C., respectively, so that the current density is 0.2 A / cm ^2. The voltage was applied with PK36-11 (manufactured by Matsusada Precision Co., Ltd.). The voltage was 50V. By this electrolysis, 14.8% lithium hydroxide 330 was recovered from the cathode chamber, and 330 ml of 15% sulfuric acid was recovered from the anode chamber. The pH of the salt chamber solution was 8 and the current efficiency was 84%.

<Comparative Example 13>
950 g of 0.4M sulfuric acid is put into a 1000 ml Erlenmeyer flask, heated to 80 ° C. in a water bath, and stirred with a stirrer. To this, 50 g of a powder containing an active material obtained in the same manner as in Example 26 was added and stirred for 3 hours to leach lithium and transition metal. 1 g of the leaching residue was taken out, put in a mixed solution of 10 ml of 5M sulfuric acid and 1 ml of 30% hydrogen peroxide solution, stirred and filtered at 80 ° C. for 3 hours, and analyzed for metal ions, and 3600 ppm of lithium was detected. .

<Comparative example 14>
Metal ions were leached in the same manner as in Example 26, and pH adjustment was performed by adding 2.28 g of 10% aqueous ammonia. The pH was 2.77. Table 1 shows the results of analyzing the concentration of metal ions in the leachate.

  Next, this leaching solution was electrodialyzed in the same manner as in Example 26. As a result of analyzing the concentration of metal ions in the recovered liquid, lithium was 3230 ppm, cobalt was 760 ppm, nickel was 770 ppm, and manganese was 50 ppm. The current efficiency at this time was 38%.

  The lithium recovery system of the present invention can be suitably used for recovering lithium from a lithium-containing solid.

DESCRIPTION OF SYMBOLS 1 Electrolysis cell 2 Anode 3 Cathode 4 Anion (anion) exchange membrane 5 Cation (cation) exchange membrane 6 Anode chamber inlet 7 Salt chamber inlet 8 Cathode chamber inlet 9 Anode chamber outlet 10 Salt chamber outlet 11 Cathode chamber outlet

Claims (13)

The following steps:
Lithium is recovered from a lithium-containing solid derived from a lithium ion battery, including a step of leaching lithium from a lithium-containing solid with an acidic leachate in which a divalent or higher-valent metal salt is dissolved in an acid to obtain a lithium recovery solution. Method. The following steps:
A desalting step of obtaining a desalted solution by desalting lithium from the lithium recovery solution in an electrodialyzer comprising a combination of a monovalent selectively permeable cation exchange membrane and an anion exchange membrane, and the desalted solution The method according to claim 1, further comprising a desalting solution recycling step in which the salt is reused as the acidic leachate.   The concentration of the divalent or higher metal salt in the acidic leachate is 7000 ppm or higher and 40,000 ppm or lower when the divalent or higher metal is cobalt, and when the divalent or higher metal is nickel. 7,000 ppm to 50,000 ppm, 7,000 ppm to 140,000 ppm when the divalent or higher metal is manganese, and 7,000 ppm to 84000 ppm when the divalent or higher metal is iron. The method according to 1 or 2.   A lithium recovery solution is obtained by leaching lithium with an acid from a lithium-containing solid, and lithium is removed from the lithium recovery solution in an electrodialysis apparatus comprising a combination of a monovalent selectively permeable cation exchange membrane and an anion exchange membrane. In the desalting step of desalting, a hydroxide and / or oxide of a divalent or higher metal and / or a reducing agent is added to the lithium recovery solution, and the pH of the lithium recovery solution is adjusted to 2-6. And a method for recovering lithium, wherein electrodialysis is performed.   The method according to claim 4, wherein the divalent or higher metal hydroxide and / or oxide is at least one metal compound selected from cobalt hydroxide, nickel hydroxide, iron hydroxide, and manganese oxide.   The method of claim 4, wherein the reducing agent comprises hydrogen peroxide or oxalic acid.   The method according to any one of claims 1 to 6, wherein the lithium recovery solution is purified by electrodialysis, and lithium hydroxide and an acid are recovered by electrolysis from the purified lithium solution.   Lithium hydroxide was added to the purified lithium solution to adjust the pH of the solution to 7 to 13, and the dissolved transition metal was precipitated as a hydroxide, and the hydroxide was separated from the solution. 8. The method according to claim 7, wherein after that, metal components other than lithium in the solution are reduced with an ion exchange resin, and then lithium hydroxide and an acid are recovered by electrolysis.   The method according to claim 7 or 8, wherein the acid is sulfuric acid.   An anode chamber, a cathode chamber, and a salt chamber sandwiched between the anode chamber and the cathode chamber, the anode chamber and the salt chamber being isolated by an anion exchange membrane, and the salt chamber and the cathode chamber 10. The method of claim 9, wherein an electrolytic apparatus isolated by a cation exchange membrane is used to produce lithium hydroxide in the cathode chamber and sulfuric acid in the anode chamber.   The method according to claim 9 or 10, wherein the pH of the purified lithium solution is adjusted to 7 to 13 using the lithium hydroxide, and the sulfuric acid is used for regeneration of the ion exchange resin.   The method according to any one of claims 1 to 11, wherein the lithium-containing solid is a lithium ion battery or a processed product thereof, or a solid discharged in a process of manufacturing a lithium ion battery.   The method according to any one of claims 1 to 12, wherein the divalent or higher metal is cobalt, nickel, manganese, and / or iron.

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