WO2020171009A1 - Procédé de récupération de lithium - Google Patents

Procédé de récupération de lithium Download PDF

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Publication number
WO2020171009A1
WO2020171009A1 PCT/JP2020/006013 JP2020006013W WO2020171009A1 WO 2020171009 A1 WO2020171009 A1 WO 2020171009A1 JP 2020006013 W JP2020006013 W JP 2020006013W WO 2020171009 A1 WO2020171009 A1 WO 2020171009A1
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Prior art keywords
liquid
lithium
treated
concentration
inorganic salt
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PCT/JP2020/006013
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English (en)
Japanese (ja)
Inventor
慶明 三保
幸則 紀平
佳帆 横山
和彦 石田
平野　悟
義浩 藤原
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Sasakura Engineering Co Ltd
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Sasakura Engineering Co Ltd
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Priority claimed from JP2019028550A external-priority patent/JP7051114B2/ja
Priority claimed from JP2019028543A external-priority patent/JP7106121B2/ja
Priority claimed from JP2019134361A external-priority patent/JP2021017627A/ja
Application filed by Sasakura Engineering Co Ltd filed Critical Sasakura Engineering Co Ltd
Priority to CN202410197802.XA priority Critical patent/CN118063026A/zh
Priority to KR1020217024265A priority patent/KR102869531B1/ko
Priority to CN202080015371.0A priority patent/CN113453788A/zh
Publication of WO2020171009A1 publication Critical patent/WO2020171009A1/fr
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00—Lithium compounds
    • C01D15/08—Carbonates; Bicarbonates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B01D61/46—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B01D61/46—Apparatus therefor
    • B01D61/461—Apparatus therefor comprising only a single cell, only one anion or cation exchange membrane or one pair of anion and cation membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B01D61/46—Apparatus therefor
    • B01D61/463—Apparatus therefor comprising the membrane sequence AC or CA, where C is a cation exchange membrane
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G51/00—Compounds of cobalt
    • C01G51/04—Oxides
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B23/00—Obtaining nickel or cobalt
    • C22B23/04—Obtaining nickel or cobalt by wet processes
    • C22B23/0407—Leaching processes
    • C22B23/0415—Leaching processes with acids or salt solutions except ammonium salts solutions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
    • C22B26/10—Obtaining alkali metals
    • C22B26/12—Obtaining lithium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/22—Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means, or by thermal decomposition
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • C22B7/008—Wet processes by an alkaline or ammoniacal leaching
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present disclosure relates to a lithium recovery method for recovering lithium from a liquid to be treated in which lithium is at least dissolved, and particularly to a lithium recovery method used when recovering lithium from a waste lithium-ion battery.
  • the present disclosure also relates to a cobalt recovery method for recovering cobalt from a liquid to be treated in which at least cobalt and impurity metals are dissolved, and particularly to a cobalt recovery method used when recovering cobalt from a waste lithium-ion battery.
  • Lithium-ion batteries are attracting attention as lightweight and high energy density batteries, and are used in large quantities as batteries for various mobile devices, electric vehicles, electrically assisted bicycles, etc.
  • a lithium transition metal oxide such as lithium cobalt oxide or lithium nickel oxide is used as a positive electrode active material, and valuable metals such as cobalt and nickel cannot be recovered from a waste lithium-ion battery.
  • Many methods have been proposed because they are extremely important from the viewpoint of effective use of resources.
  • Patent Document 1 As a method for recovering cobalt from a waste lithium-ion battery, for example, in Patent Document 1, a waste lithium-ion battery is leached with sulfuric acid to elute cobalt, and alkali is added to this acid leachate to adjust the pH to 4-5. Then, after depositing and precipitating a salt of an impurity metal such as aluminum, which is eluted together with cobalt, as a crystal, the pH is adjusted to 7 to 10 by further adding an alkali to deposit and precipitate the cobalt salt as a crystal. By this, a method for recovering cobalt is described.
  • Patent Document 2 a used lithium metal gel and a solid polymer electrolyte secondary battery are dissolved with sulfuric acid, and lithium hydroxide or ammonium hydroxide is added to a lithium sulfate-containing liquid containing lithium sulfate obtained by this.
  • a salt of an impurity metal aluminum hydroxide
  • the lithium sulfate-containing liquid is evaporated and concentrated, and then carbonated to give lithium contained in the lithium sulfate-containing liquid. Is described as a crystal of lithium carbonate, which is separated and recovered.
  • the present disclosure aims to provide a lithium recovery method capable of recovering lithium with high purity from a liquid to be treated in which lithium and an inorganic salt are dissolved.
  • a lithium recovery method includes a concentration step of evaporating and concentrating a liquid to be treated in which lithium and an inorganic salt are at least dissolved, and a liquid to be treated after the concentration step is cooled and crystallized to precipitate an inorganic salt as crystals. And a first solid-liquid separation step of separating a precipitate containing crystals of an inorganic salt from the liquid to be treated after the crystallization step, and carbon dioxide gas in the liquid to be treated after the first solid-liquid separation step. And/or adding a water-soluble carbonate, and a second solid-liquid separation step of separating a precipitate containing lithium carbonate crystals precipitated by the carbonation step from the liquid to be treated. It is characterized by having.
  • the lithium recovery method of one embodiment of the present disclosure by evaporating and concentrating the liquid to be treated in the concentration step before the carbonation step, the liquid amount of the liquid to be treated is reduced and the lithium concentration in the liquid to be treated is increased. ing. Therefore, the recovery rate of lithium carbonate can be favorably improved in the carbonation step.
  • the temperature of the liquid to be treated after evaporation and concentration is lowered, and the solubility is lowered until the inorganic salt contained in the liquid to be crystallized. I am letting you. Thereby, the concentration of the inorganic salt in the liquid to be treated can be reduced.
  • the temperature of the liquid to be treated is raised in order to reduce the solubility of lithium carbonate, so that the solubility of the inorganic salt remaining in the liquid to be treated is increased, and crystallization of the inorganic salt can be suppressed. Therefore, when recovering lithium carbonate in the carbonation step, the purity of lithium carbonate can be increased.
  • lithium can be recovered with high purity from a liquid to be treated in which lithium and an inorganic salt are dissolved.
  • FIG. 3 is a photograph of the surface state of the filtration residue of Example 1.
  • 5 is a photograph of the surface state of the filtration residue of Example 2.
  • 7 is a photograph of the surface condition of the filtration residue of Example 3.
  • the lithium recovery method of the first aspect of the present disclosure is a concentration step of evaporating and concentrating a liquid to be treated in which at least lithium and an inorganic salt are dissolved, and cooling and crystallization of the liquid to be treated after the concentration step.
  • Crystallization step of precipitating inorganic salt as crystals a first solid-liquid separation step of separating a precipitate containing inorganic salt crystals from the liquid to be treated after the crystallization step, and the first solid-liquid separation step
  • a solid-liquid separation step is a concentration step of evaporating and concentrating a liquid to be treated in which at least lithium and an inorganic salt are dissolved, and cooling and crystallization of the liquid to be treated after the concentration step.
  • the lithium recovery method described in paragraph 0016 or paragraph 0017 preferably further includes an impurity removal step of removing at least calcium and/or magnesium contained in the liquid to be treated before the concentration step.
  • the inorganic salt solution is prepared by dissolving the crystals of the inorganic salt contained in the precipitate separated from the liquid to be treated in the first solid-liquid separation step.
  • a electrodialysis step of separating and recovering an inorganic acid together with an alkali from the inorganic salt solution by performing a bipolar membrane electrodialysis on the inorganic salt solution obtained by the dissolving step. It is preferable to have.
  • the inorganic salt solution after desalting by the bipolar membrane electrodialysis is evaporated and concentrated in the concentration step.
  • a substance such as scaling that may be an obstacle in operating electrodialysis such as calcium and/or magnesium contained in the inorganic salt solution before the electrodialysis step is used. It is preferable to further include an impurity removing step of removing at least the impurities.
  • the inorganic salt contained in the inorganic salt solution is recrystallized and the crystals of the inorganic salt are separated from the inorganic salt solution before the electrodialysis step. It is preferable to further include a recrystallization step and a remelting step of dissolving the crystal of the inorganic salt obtained by the recrystallization step to generate an inorganic salt solution.
  • the inorganic acid recovered in the electrodialysis step as a regenerant for a chelate resin or an ion exchange resin used in the impurity treatment step. ..
  • condensed water generated in the concentration step causes a precipitate containing crystals of an inorganic salt obtained in the first solid-liquid separation step, and/or Alternatively, it is preferable to wash the precipitate containing the crystals of lithium carbonate obtained in the second solid-liquid separation step.
  • an acid leaching step of leaching a waste lithium ion battery with an inorganic acid to elute lithium before the concentration step, an acid leaching step of leaching a waste lithium ion battery with an inorganic acid to elute lithium, and the acid leaching step
  • a pH adjusting step of adjusting the pH by adding an alkali to the obtained lithium-containing liquid is further included, and the liquid to be treated is generated by separating the precipitate deposited by the pH adjusting step from the lithium-containing liquid.
  • the liquid to be treated is generated by separating the precipitate deposited by the pH adjusting step from the lithium-containing liquid.
  • the alkali recovered in the electrodialysis step is reused as an alkali added in the pH adjustment step, and the inorganic acid recovered in the electrodialysis step is converted into the acid. It is preferably reused as an inorganic acid used in the leaching step.
  • a roasting step of roasting the waste lithium-ion battery is further included, and in the carbonation step, Exhaust gas generated in the roasting step is preferably mixed with the liquid to be treated as carbon dioxide gas.
  • the lithium recovery method of the first aspect of the present disclosure by evaporating and concentrating the liquid to be treated in the concentration step before the carbonation step, the liquid amount of the liquid to be treated is reduced and the lithium concentration in the liquid to be treated is increased. I am letting you. Therefore, the recovery rate of lithium carbonate can be favorably improved in the carbonation step.
  • the temperature of the liquid to be treated after evaporation and concentration is lowered, and the solubility is lowered until the inorganic salt contained in the liquid to be crystallized. I am letting you. Thereby, the concentration of the inorganic salt in the liquid to be treated can be reduced.
  • the temperature of the liquid to be treated is raised in order to reduce the solubility of lithium carbonate, so that the solubility of the inorganic salt remaining in the liquid to be treated is increased, and crystallization of the inorganic salt can be suppressed. Therefore, when recovering lithium carbonate in the carbonation step, the purity of lithium carbonate can be increased.
  • FIG. 1 shows the procedure of each step in the actual form of the lithium recovery method according to the first aspect of the present disclosure
  • FIG. 2 shows a schematic configuration of a processing apparatus 10 for carrying out the lithium recovery method of FIG.
  • the lithium recovery method of the present embodiment in addition to lithium, a treatment liquid containing a strong acid such as hydrochloric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, and an inorganic salt of an alkali metal or alkaline earth metal such as potassium or sodium. It can be preferably used for processing, and particularly preferably for recovering lithium from a waste lithium-ion battery.
  • a case of recovering lithium from a waste lithium-ion battery will be described as an example.
  • the lithium recovery method of the present embodiment is -An acid leaching step S1 of leaching a waste lithium-ion battery with an inorganic acid to elute lithium -A solid-liquid separation step S2 for separating an insoluble residue from the lithium-containing liquid obtained in the acid leaching step S1, -PH adjusting steps S3 and S5 in which an alkali is added to the lithium-containing solution after the solid-liquid separation step S2 to adjust the pH, -Solid-liquid separation steps S4 and S6 for separating precipitates from the lithium-containing solution after the pH adjustment steps S3 and S5, -Impurity removing step S7 in which a chelate treatment is performed on the liquid to be treated, in which the precipitate is separated from the lithium-containing liquid after the pH adjusting steps S3 and S5, -A concentration step S8 for evaporating and concentrating the liquid to be treated in which at least lithium and an inorganic salt are dissolved after the impurity removal step S7, -A crystallization step S9 in which the
  • the lithium recovery method of the present embodiment further includes A dissolution step S13 in which crystals of an inorganic salt contained in the precipitate separated from the liquid to be treated in the solid-liquid separation step S10 are dissolved to generate an inorganic salt solution; An electrodialysis step S14 for separating and recovering an alkali and an inorganic acid from the inorganic salt solution by performing bipolar membrane electrodialysis on the inorganic salt solution after the dissolution step S13; Have.
  • the waste lithium-ion batteries for which lithium is collected are used lithium-ion batteries whose charge capacity has decreased due to the use of the specified number of times of charging and discharging, as well as semi-finished products and product specifications that occur due to defects in the battery manufacturing process. Includes old model inventory items that are generated due to changes.
  • the waste lithium-ion battery may be crushed or roasted, or may be powder obtained by crushing or roasting.
  • the acid leaching step S1 by leaching the waste lithium ion battery described above with an inorganic acid, not only lithium but also metals such as aluminum, nickel, cobalt and iron are eluted.
  • the inorganic acid for example, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid or the like can be used, but in the present embodiment, sulfuric acid is used because of its low cost and easy handling.
  • the method of leaching the waste lithium ion battery with an inorganic acid is not particularly limited, and a commonly used method can be used.
  • the waste lithium-ion battery is immersed in an aqueous solution of an inorganic acid such as an aqueous solution of sulfuric acid in the acid leaching tank 1 and stirred for a predetermined time to obtain a lithium-containing solution in which the above-described metal such as lithium is dissolved.
  • the concentration of the inorganic acid in the aqueous solution is preferably 1 mol to 5 mol/L, and the temperature of the aqueous solution is preferably 60° C. or higher.
  • the insoluble residue is separated from the lithium-containing solution by, for example, filtering the lithium-containing solution obtained in the acid leaching step S1.
  • the insoluble residue is mainly a carbon material, a metal material, or an organic material that does not dissolve in an inorganic acid.
  • various filtration devices such as pressure filtration (filter press), vacuum filtration, centrifugal filtration, and known solid-liquid separation devices such as a decanter type centrifugal separation device can be used. ..
  • alkali is added to the lithium-containing liquid (filtrate) after the solid-liquid separation step S2 to adjust the pH to a predetermined range, so that the above-mentioned metal in the lithium-containing liquid Of these, metals other than lithium are removed from the lithium-containing liquid.
  • the alkali for example, sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used, but in the present embodiment, sodium hydroxide is used because of its low cost and easy handling.
  • the method of adjusting the pH of the lithium-containing liquid is not particularly limited, and a commonly used method can be used. For example, while stirring the lithium-containing solution in the first pH adjusting tank 2 and the second pH adjusting tank 3, by adding an alkaline aqueous solution such as an aqueous solution of sodium hydroxide, the metal other than lithium in the lithium-containing solution is hydroxylated. Precipitate and precipitate as crystals of inorganic salts such as substances.
  • the pH adjusting steps S3 and S5 are divided into a first pH adjusting step S3 and a second pH adjusting step S5.
  • the pH of the lithium-containing liquid is adjusted to 4 to 7, preferably 4 to 6, and more preferably 4 to 5 by adding alkali.
  • the impurity metal (eg, aluminum, iron) in the lithium-containing liquid is precipitated and precipitated as crystals of an inorganic salt such as hydroxide (eg, aluminum hydroxide, iron hydroxide).
  • hydroxide eg, aluminum hydroxide, iron hydroxide
  • the aqueous alkali solution added in the first pH adjusting step S3 has a dilute alkali concentration of less than 1.0 mol/L.
  • the alkali concentration is excessively low, it is necessary to use a large amount of an alkaline aqueous solution for pH adjustment in the first pH adjusting step S3, and the amount of the lithium-containing liquid after the pH adjustment is also large.
  • the lower limit of the alkali concentration is preferably 0.1 mol/L or more. Further, in order to effectively suppress the removal of cobalt in the lithium-containing liquid from the lithium-containing liquid in the first pH adjusting step S3, the alkali concentration of the aqueous solution of alkali added in the first pH adjusting step S3 is It is preferably 0.5 mol/L or less, more preferably 0.2 mol/L or less.
  • a concentrated alkali concentration of 1.0 mol/L or more is used until the pH of the lithium-containing solution becomes a predetermined value smaller than 4.
  • an aqueous solution of alkali having a pH of the lithium-containing solution is added to the lithium-containing solution.
  • the pH of the lithium-containing liquid can be adjusted to 4 to 7.
  • the above-mentioned predetermined value of the pH of the lithium-containing liquid can be set within the range of 2 to 3.
  • the precipitate deposited and precipitated in the first pH step S3 is separated from the lithium-containing solution by filtering the lithium-containing solution in the next solid-liquid separation step S4, for example.
  • copper etc. may be contained in addition to the impurity metal removed from the lithium-containing liquid in the first pH adjusting step S3.
  • the precipitate is washed with a washing liquid, and the washing waste liquid after washing is supplied to the next second pH adjusting step S5 together with the lithium-containing liquid (filtrate).
  • the lithium contained in the cleaning waste liquid can also be supplied to the carbonation step S11 from the second pH adjusting step S5 together with the lithium contained in the lithium-containing solution, and the lithium can be supplied by carbonation in the carbonation step S11 described later.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8 described later. Can be effectively used.
  • the second pH adjusting step S5 an alkali is added to the lithium-containing liquid (filtrate) after the solid-liquid separation step S4 to adjust the pH to 7 or more, preferably 7 to 13, more preferably 7 to 11, and further preferably 8 Adjust to a range of ⁇ 10.
  • valuable metals for example, cobalt and nickel
  • inorganic salts such as hydroxides (for example, cobalt hydroxide and nickel hydroxide).
  • the lithium-containing liquid is heated, for example, at a constant temperature of 30° C. to 80° C.
  • the alkali concentration of the aqueous alkali solution added in the second pH adjusting step S5 is not particularly limited, but is preferably equal to or higher than that of the alkali aqueous solution used in the first pH adjusting step S3, It is preferable that the concentration is 0.2 mol/L or more.
  • the precipitate that is deposited and precipitated in the second pH step S5 is separated from the lithium-containing solution by filtering the lithium-containing solution in the next solid-liquid separation step S6, for example.
  • the valuable metal removed from the lithium-containing liquid in the second pH adjusting step S5 may also contain manganese or the like.
  • the inorganic acid sulfuric acid in this embodiment
  • alkali sulfuric acid in the present embodiment
  • An inorganic salt sodium sulfate (Na 2 SO 4 ) in this embodiment
  • the lithium-containing liquid after the pH adjusting steps S3 and S5 corresponds to the “processed liquid” of the lithium recovery method of the present disclosure. At least one of calcium, magnesium and silica may be further dissolved in the liquid to be treated.
  • the precipitate is washed with a washing liquid, and the washing waste liquid after washing is supplied to the next impurity removing step S7 together with the liquid to be treated (filtrate).
  • the lithium contained in the cleaning waste liquid can be supplied together with the lithium contained in the liquid to be treated from the impurity removal step S7 to the carbonation step S11, and the lithium is contained by carbonation in the carbonation step S11 described later. It can be collected at a high recovery rate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8 described later. Can be effectively used.
  • next impurity removing step S7 at least polyvalent cations such as calcium and/or magnesium contained in the liquid to be treated after the solid-liquid separation step S6 are removed.
  • the heat exchange efficiency can be maintained high.
  • polyvalent cations such as calcium or magnesium contained in the inorganic solution become cations of the bipolar membrane electrodialysis device 9.
  • the method of removing calcium and magnesium from the liquid to be treated in the impurity removing step S7 is not particularly limited, and for example, the polyvalent cation removing device 4 can be used.
  • the polyvalent cation removing device 4 is a device for removing divalent or more polyvalent cations such as calcium ions and magnesium ions.
  • the polyvalent cation removing device 4 has a configuration in which a liquid to be treated can be passed through a column filled with a chelate resin. It can be illustrated.
  • the chelate resin those capable of selectively capturing calcium ions and magnesium ions can be used, and examples thereof include iminodiacetic acid type and aminophosphoric acid type.
  • polyvalent cation removing device 4 examples include a device to which a chelating agent is added and a device using an ion exchange resin.
  • the impurities removed from the liquid to be treated in the impurity removal step S7 may include silica (silicate ions) in addition to calcium and magnesium.
  • the liquid to be treated after the impurity removal step S7 is heated and concentrated by evaporation, that is, the liquid in the liquid to be treated is evaporated to concentrate the liquid to be treated.
  • the liquid amount of the liquid to be processed is reduced and the lithium concentration in the liquid to be processed is increased. Therefore, the recovery rate of lithium carbonate can be improved in the carbonation step S11 described later.
  • the concentration step S8 it is preferable to concentrate the liquid to be treated to a concentration such that lithium does not precipitate as crystals of a lithium salt such as lithium sulfate in the liquid to be treated after concentration.
  • concentration of lithium in the liquid to be treated after concentration can be increased, and the recovery rate of lithium carbonate can be improved in the carbonation step S11 described later.
  • the method of evaporating and concentrating the liquid to be treated in the concentrating step S8 is not particularly limited, and, for example, the evaporative concentrating device 5 can be used.
  • the evaporative concentration device 5 is not particularly limited as long as the liquid to be treated can be concentrated by evaporation, and a known evaporative concentration device such as a heat pump type, an ejector driven type, a steam type, or a flash type can be used.
  • a heat pump type evaporative concentrator is preferable. When a heat pump type evaporative concentrator is used, the energy used can be significantly suppressed. Further, energy can be further saved by concentrating the liquid to be treated under a reduced pressure atmosphere.
  • the liquid to be treated after the concentration step S8 is cooled and crystallized.
  • the temperature of the liquid to be treated after evaporation and concentration is lowered to decrease the solubility until the inorganic salt contained in the liquid to be crystallized, so that the inorganic salt in the liquid to be treated (main In embodiments, the concentration of sodium sulfate) can be reduced. Therefore, when recovering lithium carbonate in the carbonation step S11 described later, the purity of lithium carbonate can be increased.
  • the method of cooling and crystallizing the liquid to be treated is not particularly limited, and for example, the cooling and crystallizing device 6 can be used.
  • the cooling crystallization device 6 cools the supplied liquid to be treated in a crystallization tank to precipitate crystals of an intended inorganic salt.
  • a known cooling crystallization device such as a cooling type crystallization device using a jacket or an internal coil, an external circulation cooling type crystallization device, or the like can be used and is not particularly limited.
  • the temperature dependence of the solubility of a lithium salt such as lithium sulfate is smaller than that of an inorganic salt other than the lithium salt such as sodium sulfate. That is, the inorganic salt other than the lithium salt is precipitated as crystals by cooling to a temperature not lower than the precipitation temperature of the lithium salt at the supply concentration and lower than the precipitation temperature of the inorganic salt other than the lithium salt.
  • the cooling temperature for precipitating sodium sulfate crystals is 30° C. or lower, preferably 5° C. or higher and 20° C. or lower.
  • sodium sulfate is precipitated in the form of sodium sulfate decahydrate (Na 2 SO 4 ⁇ 10H 2 O).
  • the liquid to be treated after the crystallization step S9 is filtered, for example, to separate a precipitate containing crystals of an inorganic salt (sodium sulfate in this embodiment) from the liquid to be treated.
  • an inorganic salt sodium sulfate in this embodiment
  • the liquid to be treated is mixed with carbon dioxide gas and/or a water-soluble carbonate is added to the liquid to be treated after the precipitate containing the crystals of the inorganic salt is separated.
  • the lithium therein is deposited and precipitated as crystals of lithium carbonate.
  • lithium in the liquid to be treated can be recovered as lithium carbonate.
  • the carbonate for example, sodium carbonate, ammonium carbonate, potassium carbonate or the like can be used.
  • the liquid crystal to be treated is mixed with carbon dioxide to precipitate and precipitate lithium carbonate crystals.
  • the carbonation step S11 by using a material containing no alkali metal such as sodium, it is possible to prevent alkali metal other than lithium from mixing into the precipitated lithium carbonate crystals. Therefore, highly pure lithium carbonate can be recovered.
  • the pH of the liquid to be treated will drop, and the amount of lithium carbonate deposited may decrease. Therefore, it is preferable to stop mixing the carbon dioxide gas before the pH of the liquid to be treated becomes 7 or less. Further, the pH may not be lowered by adding an alkali to the liquid to be treated. At that time, it is preferable to maintain the pH at 9 or more by adding an alkali.
  • the alkali to be added sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used.
  • the method of mixing carbon dioxide gas with the liquid to be treated is not particularly limited, and a commonly used method can be used.
  • carbon dioxide gas can be uniformly mixed with the liquid to be treated by supplying carbon dioxide gas into the liquid to be treated in the form of fine bubbles through a nozzle while stirring the liquid to be treated in the carbonation tank 7.
  • the lithium in the liquid to be treated and carbon dioxide can be reacted efficiently.
  • the liquid to be treated may be sprayed in an atmosphere of carbon dioxide to react with the carbon dioxide.
  • the solubility of lithium carbonate decreases as the temperature increases, it is preferable to heat the liquid to be treated in the carbonation step S11. As a result, the solubility of lithium carbonate produced by the reaction between lithium in the liquid to be treated and carbon dioxide gas decreases, so that the amount of precipitated lithium carbonate crystals can be increased. Further, by heating the liquid to be treated, the solubility of the inorganic salt (sodium sulfate in the present embodiment) remaining in the liquid to be treated is increased, and crystallization of the inorganic salt can be suppressed. Therefore, the precipitation of the inorganic salt crystals together with the lithium carbonate crystals can be suppressed, so that the purity of the lithium carbonate can be increased when the lithium carbonate is recovered in the carbonation step.
  • the liquid containing lithium carbonate crystals is separated from the lithium-containing liquid by filtering the liquid to be treated after the carbonation step S11, for example.
  • the precipitate separated from the lithium-containing liquid is washed with water or the like to remove impurities and increase the purity of lithium carbonate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8. It is available.
  • the liquid to be treated (filtrate) after the solid-liquid separation step S12 is not particularly limited, but since it contains impurities, part of it is discharged as blow liquid, but part of it is re-introduced into the system. It is preferable to circulate. As a result, lithium remaining in the liquid to be treated can be recovered, so that lithium can be recovered at a high recovery rate.
  • the cleaning waste liquid after cleaning the precipitate containing the lithium carbonate crystals described above is also circulated again in the system together with the liquid to be treated after the solid-liquid separation step S12.
  • the liquid to be treated after the solid-liquid separation step S12 When the liquid to be treated after the solid-liquid separation step S12 is circulated again in the system, it may be supplied to the evaporative concentration device 5 to be evaporated and concentrated in the concentration step S8, but preferably the first pH adjusting tank 2 and / Or supply to the second pH adjusting tank 3. Since the liquid to be treated after the solid-liquid separation step S12 is alkaline, it can be used as an alkali added in the pH adjusting steps S3 and S5. Furthermore, when the liquid to be treated after the solid-liquid separation step S12 contains a large amount of carbonate ions (CO 3 2 ⁇ ), the heat transfer of the heat exchanger of the evaporative concentration apparatus 5 when evaporating and concentrating in the concentration step S8. Crystals of carbonate are deposited on the surface.
  • CO 3 2 ⁇ carbonate ions
  • the lithium-containing liquid after the solid-liquid separation steps S2 and S4 is acidic, the liquid to be treated after the solid-liquid separation step S12 is neutralized with the lithium-containing liquid to use carbonate ions as carbon dioxide gas. By removing from the liquid, it is possible to prevent precipitation of carbonate crystals on the heat transfer surface of the heat exchanger of the evaporative concentration device 5 in the concentration step S8.
  • the crystals of the inorganic salt (sodium sulfate in this embodiment) contained in the precipitate separated from the liquid to be treated in the solid-liquid separation step S10 (cooling crystallization device 6) are dissolved in the dissolution step S13 (dissolution tank 8). Is supplied to.
  • the dissolving step S13 the inorganic salt crystals are dissolved in the dissolving tank 8 to have a desired concentration using, for example, water to form an inorganic salt solution.
  • the temperature at this time is not particularly limited and may be a temperature at which the crystals of the inorganic salt can be dissolved.
  • the water used for dissolving the inorganic salt is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8. It can be effectively used.
  • the generated inorganic salt solution is supplied to the bipolar membrane electrodialysis device 9.
  • the bipolar membrane electrodialysis device 9 separates and recovers the alkali and the inorganic acid from the inorganic salt solution after the dissolution step S13.
  • the bipolar membrane electrodialysis device 9 for example, as shown in FIG. 3, a cell 90 including an anion exchange membrane 91, a cation exchange membrane 92, and two bipolar membranes 93, 94 between an anode 95 and a cathode 96.
  • a three-chamber cell type bipolar membrane electrodialysis device in which a plurality of cells are laminated can be suitably used.
  • the bipolar membrane electrodialysis device 9 of the present embodiment forms a desalting chamber R1 with the anion exchange membrane 91 and the cation exchange membrane 92, and the acid chamber R2 is provided between the anion exchange membrane 91 and one bipolar membrane 93. And an alkali chamber R3 is formed between the cation exchange membrane 92 and the other bipolar membrane 94.
  • An anode chamber R4 and a cathode chamber R5 are formed outside each of the bipolar films 93, 94.
  • An anode 95 is arranged in the anode chamber R4 and a cathode 96 is arranged in the cathode chamber R5.
  • an inorganic salt solution is introduced into the desalting chamber R1, and pure water is introduced into each of the acid chamber R2 and the alkaline chamber R3. Accordingly, when the inorganic salt solution contains, for example, sodium sulfate, in the desalting chamber R1, sodium ions (Na + ) pass through the cation exchange membrane 92, and sulfate ions (SO 4 2 ⁇ ) It passes through the anion exchange membrane 91.
  • the supplied pure water is dissociated into hydrogen ions (H + ) and hydroxide ions (OH ⁇ ) in the bipolar films 93 and 94, and hydrogen ions ( H + ) combines with sulfate ions (SO 4 2 ⁇ ) to generate sulfuric acid (H 2 SO 4 ), and in the alkaline chamber R3, hydroxide ions (OH ⁇ ) combine with sodium ions (Na + ). Sodium hydroxide (NaOH) is produced.
  • sulfuric acid H 2 SO 4
  • sodium hydroxide NaOH
  • the pure water introduced into the acid chamber R2 and the alkaline chamber R3 may be condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8.
  • the demineralized diluted inorganic salt solution (desalination solution) discharged from the desalination chamber R1 is not particularly limited, it contains a small amount of lithium, so that the concentration step S8 (evaporation concentration device 5 It is preferable to supply to () and concentrate again, and then to carbonate in the carbonation step S11. Thereby, lithium can be recovered at a high recovery rate.
  • the desalted solution is supplied to the concentration step S8 in the present embodiment, when calcium and/or magnesium remains in the desalted solution, the desalted solution is supplied to the impurity removal step S7. Good. As a result, calcium and magnesium can be supplied to the concentration step S8 after being removed from the desalted solution. Further, the desalted solution may be supplied to the first pH adjusting step S3. Thereby, when cobalt remains in the desalination solution, the recovery rate of cobalt can be increased.
  • the inorganic acid (sulfuric acid in the present embodiment) recovered from the acid chamber R2 is not particularly limited, but is supplied to the acid leaching tank 1 and the inorganic acid leaching the waste lithium ion battery in the acid leaching step S1. It is preferably reused as an acid. Further, it is preferable to supply the polyvalent cation removing device 4 and reuse it as a regenerating liquid of the chelate resin or the ion exchange resin used in the impurity treatment step S7.
  • the alkali (sodium hydroxide in the present embodiment) recovered from the alkali chamber R3 is supplied to the pH adjusting tanks 2 and 3, but is not particularly limited, and the lithium-containing liquid is used in the pH adjusting steps S3 and S5. It is preferable to reuse it as an alkali for pH adjustment. Further, it is preferable to supply the polyvalent cation removing device 4 and reuse it as a regenerating liquid of the chelate resin or the ion exchange resin used in the impurity treatment step S7.
  • the lithium recovery method of the present embodiment described above by evaporating and concentrating the liquid to be treated in the concentrating step S8 before the carbonation step S11, the amount of the liquid to be treated is reduced and the lithium concentration in the liquid to be treated is reduced. Is increasing. Therefore, the recovery rate of the lithium carbonate crystals in the carbonation step S11 can be favorably improved.
  • the temperature of the liquid to be treated after evaporation and concentration is lowered and the inorganic salt (in this embodiment, sulfuric acid) contained in the liquid to be treated is reduced. Since the solubility is lowered until the sodium) crystallizes, the concentration of the inorganic salt in the liquid to be treated can be reduced.
  • the carbonation step S11 the temperature of the liquid to be treated is raised for the purpose of lowering the solubility of lithium carbonate, so that the solubility of the inorganic salt remaining in the liquid to be treated is increased and crystallization of the inorganic salt can be suppressed. .. Therefore, when recovering lithium carbonate in the carbonation step S11, the purity of lithium carbonate can be increased.
  • the lithium remaining in the liquid to be treated is circulated in the system without discarding the liquid to be treated after the crystals of lithium carbonate are recovered in the carbonation step S11. Collected. Therefore, lithium can be recovered at a high recovery rate.
  • the crystal of the inorganic salt (sodium sulfate in the present embodiment) contained in the precipitate separated from the liquid to be treated in the solid-liquid separation step S10 is dissolved in the dissolution step S13.
  • the bipolar membrane electrodialysis is performed in the electrodialysis step S14 to recover the inorganic acid and the alkali from the inorganic salt solution, and the diluted inorganic salt solution after desalting is evaporated in the concentration step S8.
  • concentration lithium contained in the dilute inorganic salt solution is recovered in the carbonation step S11. Therefore, lithium can be recovered at a high recovery rate.
  • the inorganic acids and alkalis recovered in the electrodialysis step S14 are circulated and reused in the acid leaching step S1, the pH adjusting steps S3, S5, and the impurity removing step S7, so that each step S1, S3, S5, S7 is performed. It is possible to reduce the amount of inorganic acid or alkali used in.
  • polyvalent cations such as calcium and magnesium contained in the liquid to be treated are removed in the impurity removing step S7.
  • the amount of impurities in the liquid to be treated from which the precipitate has been separated in the solid-liquid separation process S12 after the carbonation process S11 is reduced, and most of the liquid to be processed after the solid-liquid separation process S12 is returned to the system. It can circulate. Therefore, more lithium remaining in the liquid to be treated after the solid-liquid separation step S12 can be recovered, so that lithium can be recovered at a high recovery rate.
  • the condensed water generated in the concentration step S8 is used for various treatments, so that the condensed water can be effectively used. Furthermore, by washing the crystals obtained in the solid-liquid separation steps S4, S6, S10, and S12 with condensed water, the recovery rate of each crystal can be favorably improved.
  • the lithium recovery method of the first aspect is not limited to the embodiments of FIGS. 1 and 2, and does not depart from the gist of the present disclosure. Various changes are possible in.
  • the impurity removal step S7 for removing at least calcium and/or magnesium is performed on the liquid to be treated before the concentration step S8, but instead of or in addition to this, the impurity removal step S7 is performed. Then, the inorganic salt solution before the electrodialysis step S14 may be similarly subjected to the impurity removing step of removing at least calcium and/or magnesium.
  • the alkali recovered in the electrodialysis step S14 is supplied to the first pH adjusting step S3 and the second pH adjusting step S5, but it is configured to be supplied to only one of them. May be.
  • the pH adjusting steps S3 and S5 include the first pH adjusting step S3 and the second pH adjusting step S5, but three pH adjusting steps S3 and S5 are included depending on the components contained in the waste lithium ion battery. It may be configured to include the above steps, or may be configured to include only one step.
  • the inorganic salt (sodium sulfate in this embodiment) contained in the inorganic salt solution is recrystallized.
  • the method of recrystallizing the inorganic salt contained in the inorganic salt solution is not particularly limited, and for example, cooling crystallization by the cooling crystallization device 10 similar to the cooling crystallization device 6 of the crystallization step S9 described above is used. be able to.
  • the inorganic salt solution may be concentrated in advance to a concentration of the inorganic salt suitable for crystallization of the inorganic salt.
  • the cooling crystallization device 10 is used in the recrystallization step S13-1, but any crystallization method by which highly pure crystals are deposited may be used, and for example, an evaporation crystallization device may be used. it can.
  • the inorganic salt crystals are separated from the aqueous solution containing the inorganic salt crystals, and the recrystallized inorganic salt crystals are collected.
  • various filtration devices such as pressure filtration (filter press), vacuum filtration, centrifugal filtration, and known solid-liquid separation devices such as a decanter type centrifugal separation device can be used. ..
  • the crystals of the recovered inorganic salt are dissolved in the re-dissolution tank 11 using, for example, water so as to have a desired concentration, and an inorganic salt solution is regenerated.
  • the temperature at this time is not particularly limited and may be a temperature at which the crystals of the inorganic salt can be dissolved.
  • the water used for dissolving the inorganic salt is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8. It can be effectively used.
  • the regenerated inorganic salt solution is supplied to the bipolar membrane electrodialysis device 9.
  • the impurities removed from the inorganic salt solution in the recrystallization step S13-1 to the re-dissolution step S13-3 may contain calcium and/or magnesium in addition to silica.
  • silica contained in the inorganic salt solution is removed before the electrodialysis step S14.
  • the amount of impurities in the inorganic solution electrodialyzed in the electrodialysis step S14 is also reduced, so that the performance of the bipolar membrane can be maintained high.
  • the dilute inorganic salt solution (desalted solution) after the electrodialysis step S14 is supplied to the evaporative concentration apparatus 5 and evaporated and concentrated again in the concentration step S8, the amount of impurities in the desalted solution is reduced. In the concentration step S8, it is possible to suppress the generation and adhesion of scale on the heat transfer surface of the heat exchanger of the evaporative concentration device 5.
  • the embodiment of FIGS. 1 and 2 may further include a roasting step S0 of roasting the waste lithium-ion battery before the acid leaching step S1.
  • the method of roasting the waste lithium ion battery is not particularly limited, and a known roasting device 12 can be used.
  • the exhaust gas generated in the roasting device 12 (roasting step S0) is supplied to the carbonation tank 7, and the exhaust gas is mixed with the liquid to be treated as carbon dioxide in the carbonation step S11. doing. As a result, the amount of carbon dioxide gas used in the carbonation step S11 can be reduced. It is needless to say that the roasting step S0 of roasting the waste lithium-ion battery before the acid leaching step S1 can also be executed in the embodiments of FIGS. 4 and 5.
  • a second embodiment of the lithium recovery method of the present disclosure is a concentration step of heating and evaporating and concentrating a liquid to be treated in which lithium and an inorganic salt are at least dissolved at a low pressure lower than atmospheric pressure.
  • a carbonation step of mixing carbon dioxide gas and/or adding a water-soluble carbonate to the liquid to be treated after the concentration step, and a precipitate containing lithium carbonate crystals deposited by the carbonation step to be treated liquid
  • the temperature of the liquid to be treated is equal to or higher than the evaporation temperature of the liquid to be treated in the concentration step.
  • the liquid to be treated is evaporated and concentrated under a pressure of 10 kPa or more and 70 kPa or less in the concentration step.
  • an inorganic salt contained in the liquid to be treated is precipitated as crystals and separated from the liquid to be treated after the concentration step.
  • an acid leaching step of leaching a waste lithium ion battery with an inorganic acid to elute lithium, and an acid leaching step are performed before the concentration step.
  • a pH adjusting step of adjusting the pH by adding an alkali to the obtained lithium-containing liquid is further included, and the liquid to be treated is generated by separating the precipitate deposited by the pH adjusting step from the lithium-containing liquid. It is preferable.
  • the alkali recovered in the electrodialysis step is reused as an alkali added in the pH adjustment step, and the inorganic acid recovered in the electrodialysis step is converted into the acid. It is preferably reused as an inorganic acid used in the leaching step.
  • the lithium recovery method of the second aspect of the present disclosure by evaporating and concentrating the liquid to be treated in the concentration step before the carbonation step, the liquid amount of the liquid to be treated is reduced and the lithium concentration in the liquid to be treated is increased. I am letting you. Therefore, the recovery rate of lithium carbonate can be favorably improved in the carbonation step.
  • the concentration step by evaporating and concentrating the liquid to be treated under low pressure, the temperature of the liquid to be treated after evaporative concentration can be lowered as compared with evaporating and concentrating the liquid to be treated under atmospheric pressure. Therefore, there is a large room for raising the temperature of the liquid to be treated in the subsequent carbonation step, and the evaporation temperature of the liquid to be treated (boiling point of water contained in the liquid to be treated) is lowered under low pressure. Energy required for evaporative concentration can be suppressed to a low level to save energy.
  • the inorganic salt contained in the liquid to be treated is crystallized, so that the temperature of the liquid to be treated during carbonation is higher than the evaporation temperature of the liquid to be treated in the concentration step.
  • the solubility of the inorganic salt remaining in the liquid to be treated is increased, and crystallization of the inorganic salt can be suppressed during carbonation.
  • the solubility of lithium carbonate decreases, and the amount of lithium carbonate crystals recovered can be increased. Therefore, highly pure lithium carbonate can be obtained with high efficiency.
  • FIG. 8 shows the procedure of each step in the embodiment of the lithium recovery method of the second aspect of the present disclosure
  • FIG. 9 shows a schematic configuration of the processing apparatus 10 for carrying out the lithium recovery method of FIG.
  • the lithium recovery method of the present embodiment in addition to lithium, a treatment liquid containing a strong acid such as hydrochloric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, and an inorganic salt of an alkali metal or alkaline earth metal such as potassium or sodium. It can be preferably used for processing, and particularly preferably for recovering lithium from a waste lithium-ion battery.
  • a case of recovering lithium from a waste lithium-ion battery will be described as an example.
  • the lithium recovery method of the present embodiment is -An acid leaching step S1 of leaching a waste lithium-ion battery with an inorganic acid to elute lithium -A solid-liquid separation step S2 for separating an insoluble residue from the lithium-containing liquid obtained in the acid leaching step S1, -PH adjusting steps S3 and S5 in which an alkali is added to the lithium-containing solution after the solid-liquid separation step S2 to adjust the pH, -Solid-liquid separation steps S4 and S6 for separating precipitates from the lithium-containing solution after the pH adjustment steps S3 and S5, -Impurity removing step S7 in which a chelate treatment is performed on the liquid to be treated, in which the precipitate is separated from the lithium-containing liquid after the pH adjusting steps S3 and S5, -A concentration step S8 for evaporating and concentrating the liquid to be treated in which at least lithium and an inorganic salt are dissolved after the impurity removal step S7, -A solid-liquid separation step S9 for
  • the lithium recovery method of the present embodiment further includes -A dissolution step S12 in which crystals of an inorganic salt contained in the precipitate separated from the liquid to be treated in the solid-liquid separation step S9 are dissolved to generate an inorganic salt solution; An electrodialysis step S13 for separating and recovering an alkali and an inorganic acid from the inorganic salt solution by performing a bipolar membrane electrodialysis on the inorganic salt solution after the dissolution step S12, Have.
  • the waste lithium-ion battery for which lithium is to be collected is the same as that in the above-described first mode.
  • the acid leaching step S1 by leaching the waste lithium ion battery described above with an inorganic acid, not only lithium but also metals such as aluminum, nickel, cobalt and iron are eluted.
  • the inorganic acid for example, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid or the like can be used, but hydrochloric acid is used in the present embodiment.
  • the method of leaching the waste lithium ion battery with an inorganic acid is not particularly limited, and a commonly used method can be used.
  • the waste lithium-ion battery is immersed in an aqueous solution of an inorganic acid such as an aqueous solution of hydrochloric acid in the acid leaching tank 1 and stirred for a predetermined time to obtain a lithium-containing solution in which the above-described metal such as lithium is dissolved.
  • the insoluble residue is separated from the lithium-containing solution by, for example, filtering the lithium-containing solution obtained in the acid leaching step S1.
  • the insoluble residue is mainly a carbon material, a metal material, or an organic material that does not dissolve in an inorganic acid.
  • various filtration devices such as pressure filtration (filter press), vacuum filtration, centrifugal filtration, and known solid-liquid separation devices such as a decanter type centrifugal separation device can be used. ..
  • alkali is added to the lithium-containing liquid (filtrate) after the solid-liquid separation step S2 to adjust the pH to a predetermined range, so that the above-mentioned metal in the lithium-containing liquid Of these, metals other than lithium are removed from the lithium-containing liquid.
  • the alkali for example, sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used, but in the present embodiment, sodium hydroxide is used because of its low cost and easy handling.
  • the method of adjusting the pH of the lithium-containing liquid is not particularly limited, and a commonly used method can be used. For example, while stirring the lithium-containing solution in the first pH adjusting tank 2 and the second pH adjusting tank 3, by adding an alkaline aqueous solution such as an aqueous solution of sodium hydroxide, the metal other than lithium in the lithium-containing solution is hydroxylated. Precipitate and precipitate as crystals of inorganic salts such as substances.
  • the pH adjusting steps S3 and S5 are divided into a first pH adjusting step S3 and a second pH adjusting step S5.
  • the pH of the lithium-containing liquid is adjusted to 4 to 7, preferably 4 to 6, and more preferably 4 to 5 by adding alkali.
  • the impurity metal (eg, aluminum, iron) in the lithium-containing liquid is precipitated and precipitated as crystals of an inorganic salt such as hydroxide (eg, aluminum hydroxide, iron hydroxide).
  • hydroxide eg, aluminum hydroxide, iron hydroxide
  • the aqueous alkali solution added in the first pH adjusting step S3 has a dilute alkali concentration of less than 1.0 mol/L.
  • the alkali concentration is excessively low, it is necessary to use a large amount of an alkaline aqueous solution for pH adjustment in the first pH adjusting step S3, and the amount of the lithium-containing liquid after the pH adjustment is also large.
  • the lower limit of the alkali concentration is preferably 0.1 mol/L or more. Further, in order to effectively suppress the removal of cobalt in the lithium-containing liquid from the lithium-containing liquid in the first pH adjusting step S3, the alkali concentration of the aqueous solution of alkali added in the first pH adjusting step S3 is It is preferably 0.5 mol/L or less, more preferably 0.2 mol/L or less.
  • a concentrated alkali concentration of 1.0 mol/L or more is used until the pH of the lithium-containing solution becomes a predetermined value smaller than 4.
  • an aqueous solution of alkali having a pH of the lithium-containing solution is added to the lithium-containing solution.
  • the pH of the lithium-containing liquid can be adjusted to 4 to 7.
  • the above-mentioned predetermined value of the pH of the lithium-containing liquid can be set within the range of 2 to 3.
  • the precipitate deposited and precipitated in the first pH step S3 is separated from the lithium-containing solution by filtering the lithium-containing solution in the next solid-liquid separation step S4, for example.
  • copper etc. may be contained in addition to the impurity metal removed from the lithium-containing liquid in the first pH adjusting step S3.
  • the precipitate is washed with a washing liquid, and the washing waste liquid after washing is supplied to the next second pH adjusting step S5 together with the lithium-containing liquid (filtrate).
  • the lithium contained in the cleaning waste liquid can be supplied to the carbonation step S10 from the second pH adjusting step S5 together with the lithium contained in the lithium-containing solution.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8 described later. Can be effectively used.
  • the second pH adjusting step S5 alkali is added to the lithium-containing liquid after the solid-liquid separation step S4 to adjust the pH to 7 or more, preferably 7 to 13, more preferably 7 to 11, and further preferably 8 to 10. Adjust to.
  • valuable metals for example, cobalt and nickel
  • inorganic salts such as hydroxides (for example, cobalt hydroxide and nickel hydroxide).
  • the lithium-containing liquid is heated, for example, at a constant temperature of 30° C. to 80° C.
  • the alkali concentration of the aqueous alkali solution added in the second pH adjusting step S5 is not particularly limited, but is preferably equal to or higher than that of the alkali aqueous solution used in the first pH adjusting step S3, It is preferable that the concentration is 0.2 mol/L or more.
  • the precipitate that is deposited and precipitated in the second pH step S5 is separated from the lithium-containing solution by filtering the lithium-containing solution in the next solid-liquid separation step S6, for example.
  • the valuable metal removed from the lithium-containing liquid in the second pH adjusting step S5 may also contain manganese or the like.
  • the inorganic acid hydroochloric acid in the present embodiment
  • alkali in the present embodiment
  • An inorganic salt sodium chloride (NaCl) in this embodiment
  • the lithium-containing liquid after the pH adjusting steps S3 and S5 corresponds to the “processed liquid” of the lithium recovery method of the present disclosure. At least one of calcium, magnesium and silica may be further dissolved in the liquid to be treated.
  • the precipitate is washed with a washing liquid, and the washing waste liquid after washing is supplied to the next impurity removing step S8 together with the liquid to be treated (filtrate).
  • the lithium contained in the cleaning waste liquid can be supplied together with the lithium contained in the liquid to be treated from the impurity removal step S8 to the carbonation step S10, and the lithium is contained by carbonation in the carbonation step S10 described later. It can be collected at a high recovery rate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8 described later. Can be effectively used.
  • next impurity removing step S7 at least polyvalent cations such as calcium and/or magnesium contained in the liquid to be treated after the solid-liquid separation step S6 are removed.
  • the heat exchange efficiency can be maintained high.
  • the liquid to be treated contains calcium, magnesium or the like
  • polyvalent cations such as calcium or magnesium contained in the inorganic solution become cations of the bipolar membrane electrodialysis device 9.
  • the method of removing calcium and magnesium from the liquid to be treated in the impurity removing step S7 is not particularly limited, and for example, the polyvalent cation removing device 4 can be used.
  • the polyvalent cation removing device 4 is a device that removes divalent or more polyvalent cations such as calcium ions and magnesium ions.
  • the polyvalent cation removing device 4 is provided with an ion exchange resin inside, and the liquid to be treated is an ion exchange resin. As an example, it is possible to bring them into contact with each other to adsorb calcium ions or magnesium ions.
  • Other examples of the polyvalent cation removing device 4 include a device in which a liquid to be treated can be passed through a column filled with a chelate resin.
  • the chelate resin those capable of selectively capturing calcium ions and magnesium ions can be used, and examples thereof include iminodiacetic acid type and aminophosphoric acid type.
  • the polyvalent cation removing device 4 may include a device to which a chelating agent is added.
  • the impurities removed from the liquid to be treated in the impurity removal step S7 may include silica (silicate ions) in addition to calcium and magnesium.
  • the liquid to be treated after the impurity removal step S7 is heated and concentrated by evaporation, that is, the liquid in the liquid to be treated is evaporated to concentrate the liquid to be treated.
  • the liquid amount of the liquid to be processed is reduced and the lithium concentration in the liquid to be processed is increased. Therefore, the recovery rate of lithium carbonate can be improved in the carbonation step S10 described below.
  • the concentration step S8 it is preferable to evaporate and concentrate the liquid to be treated to a concentration at which lithium does not precipitate as crystals of a lithium salt such as lithium chloride in the liquid to be treated after concentration.
  • a lithium salt such as lithium chloride
  • the concentration of the inorganic salt in the liquid to be treated may be crystallized due to the concentration of the inorganic salt in the liquid to be treated being evaporated and concentrated.
  • the inorganic salt contained in the liquid to be treated may or may not be precipitated as crystals in the concentration step S8.
  • the inorganic salt contained in the liquid to be treated is precipitated as crystals in the concentration step S8, and the precipitate is separated from the liquid to be treated in the next solid-liquid separation step S9.
  • the method of evaporating and concentrating the liquid to be treated in the concentrating step S8 is not particularly limited, and, for example, the evaporative concentrating device 5 can be used.
  • the evaporative concentration device 5 is not particularly limited as long as the liquid to be treated can be concentrated by evaporation, and a known evaporative concentration device such as a heat pump type, an ejector driven type, a steam type, or a flash type can be used.
  • a heat pump type evaporative concentrator is preferable. When a heat pump type evaporative concentrator is used, the energy used can be significantly suppressed.
  • the evaporative concentration apparatus 5 is maintained at a low pressure inside by connecting a vacuum pump (not shown), and in the concentration step S8, the liquid to be treated is heated at a low pressure lower than atmospheric pressure to evaporate and concentrate. doing.
  • the temperature of the liquid to be treated rises, but under low pressure the evaporation temperature of the liquid to be treated (boiling point of water contained in the liquid to be treated) is lower than under atmospheric pressure, so evaporation at low pressure
  • the temperature of the liquid to be treated after evaporating and concentrating becomes correspondingly lower. Therefore, a large room for raising the temperature of the liquid to be treated can be secured in the carbonation step S10 described later.
  • the evaporation temperature of the liquid to be treated decreases under low pressure, the energy required for evaporating and concentrating the liquid to be treated can be kept low to save energy.
  • the pressure inside the evaporative concentration apparatus 5, that is, the atmospheric pressure when evaporating and concentrating the liquid to be treated is not particularly limited, but is preferably 10 kPa or more and 70 kPa or less, and 15 kPa or more and 50 kPa or less. Is more preferable.
  • the evaporation temperature of the liquid to be treated is preferably 45° C. or higher and 95° C. or lower, and more preferably 55° C. or higher and 80° C. or lower in view of the relationship with the pressure (saturated water vapor pressure curve).
  • the temperature of the liquid to be treated after evaporation and concentration can be set to a suitable low temperature that does not excessively decrease. Therefore, when raising the temperature of the liquid to be treated in the carbonation step S10 described later. The energy required for it can be kept low. Further, since the evaporative concentration device 5 does not need to have a very high pressure resistance, the manufacturing cost of the device can be kept low. On the other hand, when the pressure is 70 kPa or less, the temperature of the liquid to be treated after evaporation and concentration can be set to a suitable low temperature that does not rise excessively. There is enough room to raise. Further, the energy required for evaporative concentration of the liquid to be treated does not become too large, and energy saving can be effectively achieved.
  • a temperature sensor is provided in a liquid pool of the liquid to be treated at the bottom of the evaporative concentration device 5 or in a supply path of the liquid to be treated between the evaporative concentration device 5 and a carbonation tank 7 described later.
  • the evaporation temperature of the liquid to be treated (the temperature of the liquid to be treated after evaporative concentration) is monitored by the temperature sensor.
  • a pressure sensor is provided in the space above the evaporative concentration apparatus 5, and the pressure inside the evaporative concentration apparatus 5 (atmospheric pressure when evaporating and concentrating the liquid to be treated) is a pressure sensor. Being monitored by.
  • the precipitate containing the crystals of the inorganic salt is separated from the liquid to be processed after the concentration process S8 by filtering, for example.
  • the liquid to be treated is mixed with carbon dioxide gas and/or a water-soluble carbonate is added to the liquid to be treated after the precipitate containing the crystals of the inorganic salt is separated.
  • the lithium therein is deposited and precipitated as crystals of lithium carbonate.
  • lithium in the liquid to be treated can be recovered as lithium carbonate.
  • the carbonate for example, sodium carbonate, ammonium carbonate, potassium carbonate or the like can be used.
  • this carbonation step S10 it is preferable to mix carbon dioxide gas into the liquid to be treated to precipitate and precipitate lithium carbonate crystals.
  • a material containing no alkali metal such as sodium it is possible to prevent alkali metal other than lithium from mixing into the precipitated lithium carbonate crystals. Therefore, highly pure lithium carbonate can be recovered.
  • the pH of the liquid to be treated will drop, and the amount of lithium carbonate deposited may decrease. Therefore, it is preferable to stop mixing the carbon dioxide gas before the pH of the liquid to be treated becomes 7 or less. Further, the pH may not be lowered by adding an alkali to the liquid to be treated. At that time, it is preferable to maintain the pH at 9 or more by adding an alkali.
  • the alkali to be added sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used.
  • the method of mixing carbon dioxide with the liquid to be treated is not particularly limited, and a commonly used method can be used.
  • carbon dioxide gas can be uniformly mixed with the liquid to be treated by supplying carbon dioxide gas into the liquid to be treated in the form of fine bubbles through a nozzle while stirring the liquid to be treated in the carbonation tank 7.
  • the lithium in the liquid to be treated and carbon dioxide can be reacted efficiently.
  • the liquid to be treated may be sprayed in an atmosphere of carbon dioxide to react with the carbon dioxide.
  • the temperature of the liquid to be treated is set to be equal to or higher than the evaporation temperature of the liquid to be treated in the concentration step S8. If the temperature of the liquid to be treated is low during carbonation, the inorganic salt (sodium chloride in this embodiment) contained in the liquid to be treated may be crystallized. Therefore, by heating the liquid to be treated in the carbonation step S10 and raising the temperature of the liquid to be treated at the time of carbonation above the evaporation temperature of the liquid to be treated, the inorganic substances remaining in the liquid to be treated during carbonation are increased. The solubility of the salt is increased, and crystallization of the inorganic salt can be suppressed. Therefore, when recovering lithium carbonate in the carbonation step S10, the purity of lithium carbonate can be increased.
  • the inorganic salt sodium chloride in this embodiment
  • the temperature of the liquid to be treated during carbonation is not particularly limited as long as it is equal to or higher than the vaporization temperature of the liquid to be treated, but is preferably higher than the vaporization temperature of the liquid to be treated, and preferably lower than 100°C.
  • the method of heating the liquid to be treated in the carbonation step S10 is not particularly limited, and a method of heating the liquid to be treated in the carbonation tank 7 using a known heating means such as a heater is used. You can The liquid to be treated may be heated in advance by using a preheating means such as a heat exchanger before supplying the liquid to be treated to the carbonation tank 7.
  • the solubility of lithium carbonate decreases as the temperature of the liquid to be treated increases. Therefore, the temperature of the liquid to be treated rises in the carbonation step S10, so that the solubility of lithium carbonate produced by the reaction between lithium in the liquid to be treated and carbon dioxide gas decreases. Therefore, the amount of lithium carbonate crystals deposited can be increased.
  • the amount of lithium carbonate crystals recovered can be increased and the amount of inorganic salt crystals precipitated can be suppressed, so that highly pure lithium carbonate can be obtained with high efficiency.
  • the liquid to be treated after the carbonation step S10 is filtered, for example, to separate the precipitate containing lithium carbonate crystals from the lithium-containing liquid.
  • the precipitate separated from the lithium-containing liquid is washed with water or the like to remove impurities and improve the purity of lithium carbonate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8. It is available.
  • the liquid to be treated (filtrate) after the solid-liquid separation step S11 is not particularly limited, but since it contains impurities, part of it is discharged as blow liquid, but part of it is re-introduced into the system. It is preferable to circulate. As a result, lithium remaining in the liquid to be treated can be recovered, so that lithium can be recovered at a high recovery rate.
  • the cleaning waste liquid after cleaning the precipitate containing the lithium carbonate crystals is also circulated in the system together with the liquid to be treated after the solid-liquid separation step S11.
  • the liquid to be treated after the solid-liquid separation step S11 When the liquid to be treated after the solid-liquid separation step S11 is circulated in the system again, it may be supplied to the evaporative concentration apparatus 5 to be evaporated and concentrated in the concentration step S8, but preferably the first pH adjusting tank 2 and / Or supply to the second pH adjusting tank 3. Since the liquid to be treated after the solid-liquid separation step S11 is alkaline, it can be used as an alkali added in the pH adjusting steps S3 and S5. Furthermore, when the liquid to be treated after the solid-liquid separation step S11 contains a large amount of carbonate ions (CO 3 2 ⁇ ), the heat transfer of the heat exchanger of the evaporative concentration apparatus 5 when evaporating and concentrating in the concentration step S8. Crystals of carbonate are deposited on the surface.
  • CO 3 2 ⁇ carbonate ions
  • the lithium-containing liquid after the solid-liquid separation steps S2 and S4 is acidic, the liquid to be treated after the solid-liquid separation step S11 is neutralized with the lithium-containing liquid to use carbonate ions as carbon dioxide gas. By removing from the liquid, it is possible to prevent precipitation of carbonate crystals on the heat transfer surface of the heat exchanger of the evaporative concentration device 5 in the concentration step S8.
  • the crystals of the inorganic salt (sodium chloride in this embodiment) contained in the precipitate generated in the concentration step S8 (evaporative concentration device 5) and separated from the liquid to be treated in the solid-liquid separation step S9 are dissolved in the dissolution step. It is supplied to S12 (melting tank 8).
  • the inorganic salt crystals are dissolved in the dissolving tank 8 to have a desired concentration using, for example, water to produce an inorganic salt solution.
  • the temperature at this time is not particularly limited and may be a temperature at which the crystals of the inorganic salt can be dissolved.
  • the water used for dissolving the inorganic salt is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8. It can be effectively used.
  • the generated inorganic salt solution is supplied to the bipolar membrane electrodialysis device 9.
  • the bipolar membrane electrodialysis device 9 separates and recovers the alkali and the inorganic acid from the inorganic salt solution after the dissolution step S12.
  • a cell 90 including an anion exchange membrane 91, a cation exchange membrane 92, and two bipolar membranes 93, 94 between an anode 95 and a cathode 96.
  • a three-chamber cell type bipolar membrane electrodialysis device in which a plurality of cells are laminated can be suitably used.
  • the bipolar membrane electrodialysis device 9 of the present embodiment forms a desalting chamber R1 with the anion exchange membrane 91 and the cation exchange membrane 92, and the acid chamber R2 is provided between the anion exchange membrane 91 and one bipolar membrane 93. And an alkali chamber R3 is formed between the cation exchange membrane 92 and the other bipolar membrane 94.
  • An anode chamber R4 and a cathode chamber R5 are formed outside each of the bipolar films 93, 94.
  • An anode 95 is arranged in the anode chamber R4 and a cathode 96 is arranged in the cathode chamber R5.
  • an inorganic salt solution is introduced into the desalting chamber R1, and pure water is introduced into each of the acid chamber R2 and the alkaline chamber R3.
  • the inorganic salt solution contains, for example, sodium chloride
  • sodium ions (Na + ) pass through the cation exchange membrane 92 and chloride ions (Cl ⁇ ) remain in the anion chamber in the desalting chamber R1. It passes through the ion exchange membrane 91.
  • the supplied pure water is dissociated into hydrogen ions (H + ) and hydroxide ions (OH ⁇ ) in the bipolar films 93 and 94, and hydrogen ions ( H + ) combines with chloride ions (Cl ⁇ ) to generate hydrochloric acid (HCl), and in the alkaline chamber R3, hydroxide ions (OH ⁇ ) combine with sodium ions (Na + ) to form sodium hydroxide (HCl). NaOH) is produced.
  • hydrochloric acid HCl
  • sodium hydroxide NaOH
  • the pure water introduced into the acid chamber R2 and the alkaline chamber R3 may be condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8.
  • the demineralized diluted inorganic salt solution (desalination solution) discharged from the desalination chamber R1 is not particularly limited, but is supplied to the evaporative concentration device 5 because it contains a small amount of lithium. It is preferable to evaporate and concentrate again in the concentration step S8.
  • the inorganic acid (hydrochloric acid in the present embodiment) recovered from the acid chamber R2 is not particularly limited, but is supplied to the acid leaching tank 1 so as to leach the waste lithium ion battery in the acid leaching step S1. It is preferably reused as an acid. Further, it is preferable to supply the polyvalent cation removing device 4 and reuse it as a regenerating liquid of the chelate resin or the ion exchange resin used in the impurity treatment step S7.
  • the alkali (sodium hydroxide in the present embodiment) recovered from the alkali chamber R3 is supplied to the pH adjusting tanks 2 and 3, but is not particularly limited, and the lithium-containing liquid is used in the pH adjusting steps S3 and S5. It is preferable to reuse it as an alkali for pH adjustment. Further, it is preferable to supply the polyvalent cation removing device 4 and reuse it as a regenerating liquid of the chelate resin or the ion exchange resin used in the impurity treatment step S7.
  • the lithium recovery method of the present embodiment described above by evaporating and concentrating the liquid to be treated in the concentrating step S8 before the carbonation step S10, the amount of the liquid to be treated is reduced and the lithium concentration in the liquid to be treated is reduced. Is increasing. Therefore, the recovery rate of the lithium carbonate crystals in the carbonation step S10 can be favorably improved.
  • the inorganic salt (sodium chloride in the present embodiment) contained in the liquid to be treated is crystallized.
  • the solubility of the inorganic salt remaining in the liquid to be treated is increased, and crystallization of the inorganic salt can be suppressed during carbonation.
  • the solubility of lithium carbonate decreases and the amount of lithium carbonate crystals recovered increases. Therefore, highly pure lithium carbonate can be obtained with high efficiency.
  • the first pH adjusting tank 2, the second pH adjusting tank 3, the evaporative concentrating device are disposed without discarding the liquid to be treated after the lithium carbonate crystals are recovered in the carbonation step S10.
  • the lithium remaining in the liquid to be treated is recovered by circulating it in the system such as No. 5 or the like. Therefore, lithium can be recovered at a high recovery rate.
  • the crystal of the inorganic salt (sodium chloride in the present embodiment) contained in the precipitate separated from the liquid to be treated in the solid-liquid separation step S9 is dissolved in the dissolution step S12.
  • a bipolar membrane electrodialysis is performed in the electrodialysis step S13 to recover the inorganic acid and the alkali from the inorganic salt solution, and the diluted inorganic salt solution after desalting is evaporated in the concentration step S8.
  • concentration lithium contained in the dilute inorganic salt solution is recovered in the carbonation step S10. Therefore, lithium can be recovered at a high recovery rate.
  • the inorganic acids and alkalis recovered in the electrodialysis step S13 are circulated and reused in the acid leaching step S1, the pH adjusting steps S3, S5, and the impurity removing step S7, so that each step S1, S3, S5, S7 is performed. It is possible to reduce the amount of inorganic acid or alkali used in.
  • polyvalent cations such as calcium and magnesium contained in the liquid to be treated are removed in the impurity removing step S7.
  • the amount of impurities in the liquid to be treated from which the precipitate has been separated in the solid-liquid separation process S11 after the carbonation process S10 is reduced, so that most of the liquid to be processed after the solid-liquid separation process S11 is returned to the system. It can circulate. Therefore, more lithium remaining in the liquid to be treated after the solid-liquid separation step S11 can be recovered, and thus lithium can be recovered at a high recovery rate.
  • the condensed water generated in the concentration step S8 is used for various treatments, so that the condensed water can be effectively used. Further, by washing the crystals obtained in the solid-liquid separation steps S4, S6, S9, and S11 with condensed water, the recovery rate of each crystal can be improved satisfactorily.
  • the lithium recovery method of the second aspect is not limited to the embodiment of FIG. 8 and FIG. 9 and does not depart from the gist of the present disclosure. Various changes are possible in.
  • the impurity removing step S7 of removing at least calcium and/or magnesium is performed on the liquid to be treated before the concentration step S8, but instead of or in addition to this, the impurity removing step S7 is performed. Then, the inorganic salt solution before the electrodialysis step S13 may similarly be subjected to an impurity removing step of removing at least calcium and/or magnesium.
  • the alkali recovered in the electrodialysis step S13 is supplied to the first pH adjusting step S3 and the second pH adjusting step S5, but it is configured to be supplied to only one of them. May be.
  • the pH adjusting steps S3 and S5 include the first pH adjusting step S3 and the second pH adjusting step S5, but three pH adjusting steps S3 and S5 are included depending on the components contained in the waste lithium-ion battery. It may be configured to include the above steps, or may be configured to include only one step.
  • the inorganic salt (sodium chloride in this embodiment) contained in the inorganic salt solution is recrystallized.
  • the method of recrystallizing the inorganic salt contained in the inorganic salt solution is not particularly limited, and evaporative crystallization by the evaporative crystallizer 13 can be used, for example.
  • evaporative crystallization the inorganic salt solution is heated to evaporate the solvent, and the concentration of the inorganic salt is increased to precipitate crystals of the inorganic salt.
  • the evaporative concentration device 5 may be used to crystallize the inorganic salt contained in the inorganic salt solution without separately installing the evaporative crystallization device 10.
  • the inorganic salt crystals are separated from the aqueous solution containing the inorganic salt crystals, and the recrystallized inorganic salt crystals are recovered.
  • various filtration devices such as pressure filtration (filter press), vacuum filtration, centrifugal filtration, and known solid-liquid separation devices such as a decanter type centrifugal separation device can be used. ..
  • the crystals of the recovered inorganic salt are dissolved in the re-dissolution tank 11 using water, for example, so as to have a desired concentration, and an inorganic salt solution is regenerated.
  • the temperature at this time is not particularly limited and may be a temperature at which the crystals of the inorganic salt can be dissolved.
  • the water used for dissolving the inorganic salt is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S8. It can be effectively used.
  • the regenerated inorganic salt solution is supplied to the bipolar membrane electrodialysis device 9.
  • the impurities removed from the inorganic salt solution in the recrystallization step S12-1 to the redissolution step S12-3 may include calcium and/or magnesium in addition to silica.
  • silica contained in the inorganic salt solution is removed before the electrodialysis step S13.
  • the amount of impurities in the inorganic solution electrodialyzed in the electrodialysis step S13 is also reduced, so that the performance of the bipolar membrane can be maintained high.
  • the dilute inorganic salt solution (desalted solution) after the electrodialysis step S13 is supplied to the evaporative concentration apparatus 5 and evaporated and concentrated again in the concentration step S8, the amount of impurities in the desalted solution is reduced. In the concentration step S8, it is possible to suppress the generation and adhesion of scale on the heat transfer surface of the heat exchanger of the evaporative concentration device 5.
  • a roasting step S0 of roasting the waste lithium-ion battery may be further included before the acid leaching step S1.
  • the method of roasting the waste lithium ion battery is not particularly limited, and a known roasting device 12 can be used.
  • the exhaust gas generated in the roasting device 12 (roasting step S0) is supplied to the carbonation tank 7, and the exhaust gas is mixed with the liquid to be treated as carbon dioxide in the carbonation step S10. doing. As a result, the amount of carbon dioxide gas used in the carbonation step S10 can be reduced. Further, the liquid to be treated can be heated in the carbonation step S10. It is needless to say that the roasting step S0 of roasting the waste lithium-ion battery before the acid leaching step S1 can also be executed in the embodiments of FIGS. 11 and 12.
  • the lithium recovery method of the above-described embodiment exemplifies the case of recovering lithium from a waste lithium-ion battery
  • the lithium recovery method of the present disclosure is applicable to a method used to recover lithium from a waste lithium-ion battery. Is not limited.
  • Cobalt recovery method Recovery of valuable metal cobalt from waste lithium-ion batteries is extremely important from the viewpoint of effective use of resources.
  • the pH of the acid leachate is set to 4 or more in order to remove the impurity metal such as aluminum from the acid leachate.
  • cobalt crystals may be precipitated and precipitated together with the salt crystals of, and cobalt may be removed from the acid leachate together with impurity metals, and the recovery rate of cobalt may be low during subsequent cobalt recovery. ..
  • the present disclosure aims to provide a cobalt recovery method capable of recovering cobalt at a high recovery rate from a liquid to be treated in which cobalt and impurity metals are dissolved.
  • the present inventor as a result of intensive studies to solve the above problems, when the salt of the impurity metal is precipitated as crystals by adjusting the pH of the liquid to be treated in which cobalt and the impurity metal are at least dissolved, to be treated It has been found that when the concentration of the aqueous alkali solution added to the solution is high, cobalt salt crystals precipitate together with the impurity metal salt crystals, and cobalt is removed from the liquid to be treated together with the impurity metal.
  • the cobalt recovery method of the present disclosure has been completed as a result of further research based on such knowledge. That is, the present disclosure provides the following method for recovering cobalt.
  • an aqueous alkali solution is added to an acidic liquid to be treated in which cobalt and an impurity metal are at least dissolved to adjust the pH to 4 to 7, thereby precipitating a salt of the impurity metal as crystals.
  • the alkali concentration of the aqueous alkali solution added in the first pH adjusting step is 0.1 mol/L or more.
  • an alkali having an alkali concentration of 1.0 mol/L or more is used until the pH of the liquid to be treated reaches a predetermined value smaller than 4. It is preferable that the pH of the liquid to be treated is adjusted to 4 to 7 by adding the aqueous solution of 1 to the liquid to be treated and then adding the aqueous solution of alkali having an alkali concentration of less than 1.0 mol/L to the liquid to be treated. ..
  • lithium is dissolved in the liquid to be treated, and a concentration step of evaporating and concentrating the liquid to be treated after the second solid-liquid separation step, It is preferable to have a carbonation step of mixing carbon dioxide gas and/or adding a water-soluble carbonate to the liquid to be treated after the concentration step.
  • a third solid-liquid separation step of separating a precipitate containing crystals of lithium carbonate precipitated by the carbonation step from a liquid to be treated and the third solid-liquid separation step.
  • the alkali concentration is less than 1.0 mol/L for the liquid to be treated in which cobalt and the impurity metal are dissolved.
  • FIG. 15 shows the procedure of each step in the embodiment of the cobalt recovery method of the present disclosure
  • FIG. 16 shows a schematic configuration of the processing apparatus 10 for carrying out the cobalt recovery method of FIG.
  • the cobalt recovery method of the present embodiment will be described by taking the case of recovering lithium in addition to cobalt from a waste lithium-ion battery as an example.
  • the cobalt recovery method of this embodiment is -An acid leaching step S1 of leaching a waste lithium-ion battery with an inorganic acid to elute cobalt and lithium; -Solid-liquid separation step S2 for separating insoluble residues from the liquid to be treated obtained in the acid leaching step S1, and-Adding an aqueous alkali solution to the liquid to be treated after the solid-liquid separation step S2 to adjust the pH to 4 to 7.
  • a first pH adjusting step S3 for adjusting, -A solid-liquid separation step S4 (corresponding to the "first solid-liquid separation step” described in paragraph 0163) for separating the precipitate containing the crystals of the impurity metal salt precipitated by the first pH adjusting step S3 from the liquid to be treated; -A second pH adjusting step S5 of adjusting the pH to 7 or more by adding an aqueous alkali solution to the liquid to be treated after the solid-liquid separation step S4; -A solid-liquid separation step S6 (corresponding to the "second solid-liquid separation step” described in paragraph 0163) for separating the precipitate containing the cobalt salt crystals precipitated by the second pH adjusting step S5 from the liquid to be treated, -A concentration step S7 of evaporating and concentrating the liquid to be treated after the solid-liquid separation step S6, -A carbonation step S8 of mixing carbon dioxide gas and/or adding a water-soluble carbonate to the liquid to be treated after the concentration step S7, -A solid-
  • the waste lithium-ion battery for which cobalt is to be recovered is the same as the lithium recovery method described above.
  • the acid leaching step S1 not only cobalt and lithium but also metals such as aluminum, nickel and iron are eluted by leaching the above-mentioned waste lithium-ion battery with an inorganic acid.
  • an inorganic acid for example, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid or the like can be used, but in the present embodiment, sulfuric acid is used because of its low cost and easy handling.
  • the method of leaching the waste lithium ion battery with an inorganic acid is not particularly limited, and a commonly used method can be used.
  • the waste lithium-ion battery is immersed in an aqueous solution of an inorganic acid such as a sulfuric acid aqueous solution in the acid leaching tank 1 and stirred for a predetermined time to obtain an acidic liquid to be treated in which the above-described metal such as cobalt is dissolved.
  • the concentration of the inorganic acid in the aqueous solution is preferably 1 mol to 5 mol/L, and the temperature of the aqueous solution is preferably 60° C. or higher.
  • the insoluble residue is separated from the liquid to be treated by, for example, filtering the liquid to be treated obtained in the acid leaching step S1.
  • the insoluble residue is mainly a carbon material, a metal material, or an organic material that does not dissolve in an inorganic acid.
  • various filtration devices such as pressure filtration (filter press), vacuum filtration, centrifugal filtration, and known solid-liquid separation devices such as a decanter type centrifugal separation device can be used. ..
  • an aqueous alkali solution is added to the liquid to be treated (filtrate) after the solid-liquid separation step S2 to adjust the pH to 4 to 7, preferably 4 to 6, and more preferably 4 to 5. adjust.
  • the impurity metal eg, aluminum or iron
  • sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used as the alkali, lithium hydroxide is used in the present embodiment.
  • the method of adjusting the pH of the liquid to be treated in the first pH adjusting step S3 is not particularly limited, and a commonly used method can be used. For example, by adding an alkaline aqueous solution such as an aqueous solution of lithium hydroxide while stirring the liquid to be treated in the first pH adjusting tank 2, the impurity metals in the liquid to be treated are converted into hydroxides (for example, aluminum hydroxide and water). It precipitates and precipitates as crystals of an inorganic salt such as iron oxide.
  • the first pH adjusting step S3 is preferably performed while heating the liquid to be treated at a constant temperature of, for example, 30°C to 80°C.
  • the aqueous alkali solution added in the first pH adjusting step S3 has a dilute alkali concentration of less than 1.0 mol/L.
  • the lower limit of the alkali concentration is preferably 0.1 mol/L or more.
  • the alkali concentration of the aqueous solution of alkali added in the first pH adjusting step S3 is It is preferably 0.5 mol/L or less, more preferably 0.2 mol/L or less.
  • a concentrated alkali concentration of 1.0 mol/L or more is used until the pH of the liquid to be treated reaches a predetermined value smaller than 4.
  • an aqueous solution of an alkali having a low alkali concentration of less than 1.0 mol/L is added to the solution to be treated.
  • the pH of the liquid to be treated can be adjusted to 4 to 7.
  • the predetermined value of the pH of the liquid to be treated can be set within the range of 2 to 3.
  • the precipitate deposited and precipitated in the first pH step S3 is separated from the liquid to be treated in the next solid-liquid separation step S4 by filtering the liquid to be treated, for example.
  • the impurity metal removed from the liquid to be treated in the first pH step S3 may further contain copper or the like.
  • the precipitate is washed with a washing liquid, and the washing waste liquid after washing is supplied to the next second pH adjusting step S5 together with the liquid to be treated (filtrate).
  • the lithium contained in the cleaning waste liquid can be supplied together with the lithium contained in the liquid to be treated from the second pH adjusting step S5 to the carbonation step S8. Can be recovered at a high recovery rate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S7 described later. Can be effectively used.
  • an aqueous solution of alkali is added to the liquid to be treated (filtrate) after the solid-liquid separation step S4 to adjust the pH to 7 or more, preferably 7 to 13, more preferably 7 to 11, and further preferably. Adjust to 8-10.
  • valuable metals such as cobalt and nickel are removed from the liquid to be treated.
  • sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used as the alkali, lithium hydroxide is used in the present embodiment.
  • the method of adjusting the pH of the liquid to be treated is not particularly limited, and a commonly used method can be used.
  • an aqueous alkali solution such as an aqueous lithium hydroxide solution
  • the valuable metal in the liquid to be treated is converted into a hydroxide (for example, iron cobalt hydroxide, Further, it is precipitated and precipitated as crystals of an inorganic salt such as nickel hydroxide).
  • a cobalt salt such as cobalt hydroxide.
  • the second pH adjusting step S5 is preferably performed while heating the liquid to be treated at a constant temperature of, for example, 30°C to 80°C.
  • the alkali concentration of the aqueous alkali solution added in the second pH adjusting step S5 is not particularly limited, but is preferably equal to or higher than that of the alkali aqueous solution used in the first pH adjusting step S3, It is preferable that the concentration is 0.2 mol/L or more.
  • the precipitate deposited and precipitated in the second pH step S5 is separated from the liquid to be treated in the next solid-liquid separation step S6 by filtering the liquid to be treated, for example.
  • the valuable metal removed from the liquid to be treated in the second pH adjusting step S5 may further contain manganese or the like.
  • the liquid to be treated (filtrate) after the solid-liquid separation step S6 contains anions (for example, sulfate ions) of lithium and an inorganic acid.
  • the precipitate is washed with a washing liquid, and the washing waste liquid after washing is supplied to the next concentration step S7 together with the liquid to be treated (filtrate).
  • the lithium contained in the cleaning waste liquid can be supplied to the carbonation step S8 from the concentration step S7 together with the lithium contained in the liquid to be treated. It can be recovered with a recovery rate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S7. It is available.
  • the first pH adjusting step S3 and the second pH adjusting step S5 by using lithium hydroxide as an alkali to be used, as compared with the case of using a hydroxide of another alkali metal such as sodium hydroxide, it will be described later.
  • the lithium carbonate crystals precipitated in the carbonation step S8 the mixing of alkali metals other than lithium such as sodium can be suppressed. Therefore, highly pure lithium carbonate can be recovered.
  • the liquid to be treated containing lithium after the solid-liquid separation step S6 is evaporated and concentrated by heating, that is, the liquid to be treated is concentrated by evaporating the water in the liquid to be treated.
  • the liquid amount of the liquid to be processed is reduced and the lithium concentration in the liquid to be processed is increased. Therefore, the recovery rate of lithium carbonate can be improved in the carbonation step S8 described later.
  • the temperature of the concentrated liquid to be treated can be raised by evaporating and concentrating the liquid to be treated, and the recovery rate of lithium carbonate can be improved in the carbonation step S8 described later. .. Since the solubility of lithium carbonate decreases as the temperature increases, the solubility of lithium carbonate generated by the reaction between lithium in the liquid to be treated and carbon dioxide gas decreases as the temperature of the liquid to be treated increases in the carbonation step S8. Therefore, the amount of crystals of lithium carbonate deposited can be increased.
  • the concentration step S7 it is preferable to concentrate the liquid to be treated to a concentration such that lithium does not precipitate as crystals of a lithium salt such as lithium sulfate in the liquid to be treated after concentration.
  • concentration of lithium in the liquid to be treated after concentration can be increased, and the recovery rate of lithium carbonate can be improved in the carbonation step S8 described later.
  • a solid-liquid separation step of separating it from the liquid to be treated may be performed.
  • the method of evaporating and concentrating the liquid to be treated is not particularly limited, and, for example, the evaporative concentration device 5 can be used.
  • the evaporative concentration device 5 is not particularly limited as long as the liquid to be treated can be concentrated by evaporation, and a known evaporative concentration device such as a heat pump type, an ejector driven type, a steam type, or a flash type can be used.
  • a heat pump type evaporative concentrator is preferable. When a heat pump type evaporative concentrator is used, the energy used can be significantly suppressed. Further, energy can be further saved by concentrating the liquid to be treated under a reduced pressure atmosphere.
  • next carbonation step S8 carbon dioxide is mixed with the liquid to be treated after the concentration step S7 and/or a water-soluble carbonate is added to deposit lithium in the liquid to be treated as crystals of lithium carbonate, Allow to settle. Thereby, lithium in the liquid to be treated can be recovered as lithium carbonate.
  • the carbonate for example, sodium carbonate, ammonium carbonate, potassium carbonate or the like can be used.
  • the liquid crystal to be treated is mixed with carbon dioxide gas to precipitate and precipitate lithium carbonate crystals.
  • the carbonation step S8 by using a material containing no alkali metal such as sodium, it is possible to prevent alkali metal other than lithium from mixing into the precipitated lithium carbonate crystals. Therefore, highly pure lithium carbonate can be recovered.
  • the method of mixing carbon dioxide with the liquid to be treated is not particularly limited, and a commonly used method can be used.
  • carbon dioxide gas can be uniformly mixed with the liquid to be treated by supplying carbon dioxide gas into the liquid to be treated in the form of fine bubbles from the nozzle while stirring the liquid to be treated in the carbonation tank 7. Lithium in the liquid to be treated and carbon dioxide can be reacted efficiently.
  • the liquid to be treated may be sprayed in an atmosphere of carbon dioxide to react with the carbon dioxide.
  • solubility of lithium carbonate decreases as the temperature increases, it is preferable to heat the liquid to be treated in the carbonation step S8. As a result, the solubility of lithium carbonate produced by the reaction between lithium in the liquid to be treated and carbon dioxide gas decreases, so that the amount of precipitated lithium carbonate crystals can be increased.
  • the liquid to be treated after the carbonation step S8 is filtered, for example, to separate precipitates containing lithium carbonate crystals from the liquid to be treated.
  • the precipitate separated from the liquid to be treated can be washed with water or the like to remove impurities and increase the purity of lithium carbonate.
  • the water used for washing the precipitate is not particularly limited, but it is preferable to use the condensed water generated when the liquid to be treated is evaporated and concentrated in the concentration step S7. It is available.
  • the washing waste liquid after washing the precipitate is preferably supplied to the bipolar membrane electrodialysis device 6 in the electrodialysis step S10 described later together with the liquid to be treated (filtrate) after the solid-liquid separation step S9.
  • the liquid to be treated after the solid-liquid separation step S9 is supplied to the bipolar membrane electrodialysis device 6 to separate and recover the alkali and inorganic acid from the liquid to be treated.
  • the bipolar membrane electrodialysis device 9 for example, as shown in FIG. 17, a cell 90 including an anion exchange membrane 91, a cation exchange membrane 92, and two bipolar membranes 93, 94 between an anode 95 and a cathode 96.
  • a three-chamber cell type bipolar membrane electrodialysis device in which a plurality of cells are laminated can be suitably used.
  • the bipolar membrane electrodialysis device 9 of the present embodiment forms a desalting chamber R1 with the anion exchange membrane 91 and the cation exchange membrane 92, and the acid chamber R2 is provided between the anion exchange membrane 91 and one bipolar membrane 93. And an alkali chamber R3 is formed between the cation exchange membrane 92 and the other bipolar membrane 94.
  • An anode chamber R4 and a cathode chamber R5 are formed outside each of the bipolar films 93, 94.
  • An anode 95 is arranged in the anode chamber R4 and a cathode 96 is arranged in the cathode chamber R5.
  • the liquid to be treated is introduced into the desalting chamber R1 and pure water is introduced into the acid chamber R2 and the alkaline chamber R3 respectively, so that the liquid to be treated is anion of lithium and an inorganic acid (this embodiment).
  • lithium ions Li +
  • sulfate ions SO 4 2 ⁇
  • the supplied pure water is dissociated into hydrogen ions (H + ) and hydroxide ions (OH ⁇ ) in the bipolar films 93 and 94, and hydrogen ions ( H + ) combines with sulfate ions (SO 4 2 ⁇ ) to generate sulfuric acid (H 2 SO 4 ), and in the alkaline chamber R3, hydroxide ions (OH ⁇ ) combine with lithium ions (Li + ) Lithium hydroxide (LiOH) is produced.
  • the dilute desalination liquid (desalination liquid) discharged from the desalting chamber R1 is not particularly limited, but since it contains a small amount of lithium, at least a part of the concentration step S7 ( It is preferable to supply it to the evaporative concentrating device 5) or the impurity removing process (multivalent cation removing device) before the concentrating process S7 described later, concentrate again in the concentrating process S7, and then carbonate in the carbonating process S8. Thereby, lithium can be recovered at a high recovery rate.
  • the desalted solution is supplied to the concentration step S7 in this embodiment, it may be supplied to the first pH adjustment step S3. Thereby, when cobalt remains in the desalination solution, the recovery rate of cobalt can be increased.
  • the inorganic acid (sulfuric acid in the present embodiment) recovered from the acid chamber R2 is not particularly limited, but is supplied to the acid leaching tank 1 and the inorganic acid leaching the waste lithium ion battery in the acid leaching step S1. It is preferably reused as an acid.
  • the alkali (lithium hydroxide in the present embodiment) recovered from the alkali chamber R3 is supplied to the pH adjusting tanks 2 and 3, but is not particularly limited, and the liquid to be treated in the pH adjusting steps S3 and S5. It is preferable to reuse it as an alkali for pH adjustment.
  • the alkali concentration is 1.
  • the cobalt recovery method of the present embodiment since a dilute alkaline aqueous solution having an alkali concentration of less than 1.0 mol/L is used in the first pH adjusting step S3, carbon dioxide for recovering lithium thereafter is used.
  • the liquid amount of the liquid to be processed supplied to the liquefying process S8 becomes large, the liquid amount of the liquid to be processed is reduced by evaporating and concentrating the liquid to be processed in the concentrating process S7 before the carbonation process S8. Increasing the lithium concentration in the liquid. Therefore, the recovery rate of lithium carbonate can be favorably improved in the carbonation step S8.
  • the solubility of lithium carbonate decreases and the amount of lithium carbonate deposited can be increased.
  • the aqueous alkali solution having an alkali concentration of 1.0 mol/L or more is applied until the pH of the liquid to be treated reaches a predetermined value.
  • an aqueous solution of alkali having an alkali concentration of less than 1.0 mol/L is added to the liquid to be treated so that an aqueous alkali solution used for pH adjustment. The amount can be reduced.
  • the inorganic acid and the alkali recovered in the electrodialysis step S10 are circulated and reused in the acid leaching step S1 and the pH adjusting steps S3 and S5, respectively.
  • the amount of inorganic acid or alkali used in S1, S3, S5 can be reduced.
  • the cobalt recovery method of the present disclosure is not limited to the embodiments of FIGS. 15 and 16, and various modifications are possible without departing from the spirit of the present disclosure. Can be changed.
  • the alkali recovered in the electrodialysis step S10 is supplied to the first pH adjusting step S3 and the second pH adjusting step S5, but it is configured to be supplied to only one of them. May be.
  • At least a part of the diluted liquid to be treated (desalted liquid) after the lithium hydroxide is recovered in the electrodialysis process S10 is supplied to the concentration process S7.
  • it may be configured to supply to the electrodialysis step S10.
  • the concentration step S7 is provided before the carbonation step S8, but the concentration step S7 does not necessarily have to be provided.
  • at least a part of the diluted liquid to be treated (desalted liquid) after the lithium hydroxide is recovered in the electrodialysis process S10 can be configured to be supplied to the carbonation process S8.
  • polyvalent cations having a valence of 2 or more in the liquid to be treated may be removed.
  • polyvalent cations such as calcium ions and magnesium ions are present in the liquid to be treated, these polyvalent cations are deposited in the cation exchange membrane of the bipolar membrane electrodialysis device 9 to reduce the performance of the membrane.
  • the specific structure for removing the polyvalent cations is not particularly limited, and for example, a known polyvalent cation removing device capable of passing a liquid to be treated through a column filled with a chelate resin is exemplified. You can As the chelate resin, those capable of selectively capturing calcium ions and magnesium ions can be used, and examples thereof include iminodiacetic acid type and aminophosphoric acid type. Other examples of the polyvalent cation removing device include a device adding a chelating agent and a device utilizing an ion exchange resin. The impurities removed from the liquid to be treated may contain silica (silicate ions) in addition to calcium and magnesium.
  • a roasting step S0 of roasting the waste lithium-ion battery may be further provided before the acid leaching step S1.
  • the method of roasting the waste lithium ion battery is not particularly limited, and a known roasting device 12 can be used.
  • the exhaust gas generated in the roasting device 12 is supplied to the carbonation tank 7 (carbonation step S8) and mixed with the liquid to be treated as carbon dioxide gas. ing. Thereby, the amount of carbon dioxide gas used in the carbonation step S8 can be reduced.
  • the method of recovering lithium in the steps after the concentration step S7 is not particularly limited, and the lithium recovery method of the present disclosure described above may be used.
  • the lithium recovery method of the above-described embodiment uses the cobalt recovery method of the present disclosure in the acid leaching step S1 to the solid-liquid separation step S6.
  • the cobalt recovery method of the above-described embodiment exemplifies the case of recovering cobalt from a waste lithium-ion battery
  • the cobalt recovery method of the present disclosure is used to recover cobalt from a waste lithium-ion battery.
  • the method is not limited.
  • Test Example The present inventor conducted the following test on the alkali concentration of the aqueous solution of alkali added in the first pH adjusting step S3. Specifically, a process (first pH adjusting step S3) of adjusting the pH of the liquid to be processed by adding an alkaline aqueous solution to 200 ml of the liquid to be processed having the components shown in Table 1 below was performed. An aqueous solution of lithium hydroxide was used as the aqueous solution of alkali to be added.
  • the alkali concentration of the lithium hydroxide aqueous solution was 0.2 mol/L (Example 1), 0.5 mol/L (Example 2), and 1.0 mol/L (Example 3), and the pH of the liquid to be treated was 4
  • the addition amount of the lithium hydroxide aqueous solution was adjusted so as to be 0.7.
  • the amount of the lithium hydroxide aqueous solution added was 418.6 ml in Example 1, 168.5 ml in Example 2, and 86.3 ml in Example 3.
  • the content of lithium in the liquid to be treated was increased by 582 mg in Example 1, 585 mg in Example 2, and 599 mg in Example 3 by the addition of the aqueous lithium hydroxide solution.
  • FIGS. 20 to 22 show the surface condition of the filtration residue obtained by filtering the liquid to be treated after pH adjustment.
  • 20 shows the first embodiment
  • FIG. 21 shows the second embodiment
  • FIG. 22 shows the third embodiment.
  • the alkaline concentration of the alkaline aqueous solution added to the liquid to be treated in the first pH adjusting step S3 is 1.0 mol/L
  • the cobalt recovery rate of the liquid to be treated (filtrate) after pH adjustment Is less than 85%
  • the alkali concentration is less than 1.0 mol/L
  • the cobalt recovery rate of the liquid to be treated (filtrate) after pH adjustment is 85% or more. It was confirmed that a large amount of cobalt remained in the liquid (filtrate).

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Abstract

L'invention concerne un procédé de récupération de lithium grâce auquel du lithium très pur peut être récupéré à partir d'un fluide à traiter qui a du lithium et un sel inorganique dissous dans celui-ci. Le procédé de récupération de lithium comprend : une étape de concentration S8 dans laquelle le fluide à traiter qui a au moins du lithium et un sel inorganique dissous dans celui-ci est concentré par évaporation; une étape de cristallisation S9 dans laquelle le fluide à traiter est refroidi et cristallisé après l'étape de concentration S8 et le sel inorganique est précipité sous forme de cristaux; une étape S10 de séparation solide/liquide dans laquelle un précipité comprenant des cristaux de sel inorganique est séparé du fluide à traiter, après l'étape de cristallisation S9; une étape de carbonatation S11 dans laquelle du dioxyde de carbone gazeux est mélangé dans et/ou un carbonate soluble dans l'eau est ajouté au fluide à traiter, après l'étape de séparation solide/liquide S10; et une étape S12 de séparation solide/liquide dans laquelle un précipité comprenant des cristaux de carbonate de lithium précipité dans l'étape de carbonatation S11 est séparé du fluide à traiter.
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EP4484384A1 (fr) * 2023-06-29 2025-01-01 SK Innovation Co., Ltd. Procédé de récupération d'acide et d'alcali à partir de raffinat généré à partir d'un processus d'extraction de métal
WO2025028499A1 (fr) * 2023-08-01 2025-02-06 国立大学法人弘前大学 Procédé de traitement de solution aqueuse contenant des ions lithium
WO2025170828A1 (fr) * 2024-02-09 2025-08-14 Veolia Water Technologies, Inc. Procédé de génération de déchets sans rejet liquide et d'amélioration de la récupération de lithium dans des installations de production de lithium

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