Treatment method for lithium / nickel / cobalt-containing material

Abstract

Provided is a treatment method for a lithium / nickel / cobalt-containing material that includes a leaching step (S01) for adding an acidic solution that contains an inorganic acid to a lithium / nickel / cobalt-containing material to leach lithium, nickel, and cobalt into the acidic solution, a reduction leaching step (S02) for adding a reducing agent to the acidic solution to leach more lithium, nickel, and cobalt, a neutralization step (S03) for adding a calcium compound to the lithium / nickel / cobalt leachate to generate a nickel / cobalt precipitate that includes nickel and cobalt, a solid / liquid separation step (S04) for separating the nickel / cobalt precipitate and the lithium leachate, and a nickel / cobalt recovery step (S05) for recovering nickel and cobalt from the nickel / cobalt precipitate.

Description

Processing method for materials containing lithium, nickel, and cobalt

[0001] The present invention relates to a method for treating a lithium-nickel-cobalt-containing material, which recovers valuable metals such as lithium, nickel, and cobalt from the lithium-nickel-cobalt-containing material. This application claims priority based on Japanese Patent Application No. 2024-089446, filed May 31, 2024, the contents of which are incorporated herein by reference.

[0002] In recent years, lithium has been recovered and reused from crushed lithium-ion batteries. When recovering lithium from lithium-ion batteries, it is common to use waste lithium-ion battery powder, which is obtained by firing and / or crushing used lithium-ion batteries, a recycled raw material known as black mass, or defective products generated during the secondary battery manufacturing process, known as black powder. The waste lithium-ion battery powder contains metals such as nickel and cobalt in addition to lithium. Therefore, technologies for recovering nickel and cobalt from waste lithium-ion battery powder have been proposed.

[0003] For example, Patent Document 1 proposes a technology for recovering lithium by leaching battery sludge containing lithium aluminate obtained by roasting lithium-ion battery waste in an acidic solution, neutralizing the resulting leachate and performing solid-liquid separation to separate the lithium solution from metals such as aluminum, nickel, and cobalt. Patent Document 2 proposes a method for recovering lithium by crushing and classifying lithium-ion secondary batteries to obtain an electrode material containing cobalt and nickel, immersing the electrode material in a treatment solution containing sulfuric acid and hydrogen peroxide to produce a leachate, separating copper from the leachate to obtain an eluate containing cobalt and nickel, adding an alkali metal hydroxide to the eluate to adjust the pH, adding a hydrogen sulfide compound, stirring, and performing solid-liquid separation to separate the eluate into cobalt sulfide and nickel sulfide and a residual solution containing lithium.

[0004] Japanese Unexamined Patent Publication No. 2019-160429 (A) Japanese Unexamined Patent Application No. 2022-042982 (A)

[0005] However, waste lithium-ion battery powder obtained by calcining and pulverizing used lithium-ion batteries contains cobalt and nickel as described above, and may also contain complex compounds that are difficult to dissolve in acid. The method disclosed in Patent Document 1 has a problem in that it is not possible to sufficiently dissolve cobalt and nickel. Furthermore, the method disclosed in Patent Document 2 involves immersing an electrode material in a treatment solution containing sulfuric acid and hydrogen peroxide to obtain a leachate. While this method is capable of dissolving cobalt and nickel, it also contains lithium, which makes it difficult to efficiently recover lithium, nickel, and cobalt.

[0006] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method for treating a lithium-nickel-cobalt-containing material that can efficiently recover valuable metals such as lithium, nickel, and cobalt from a lithium-nickel-cobalt-containing material that contains lithium, cobalt, and nickel.

[0007] In order to solve the above problems, a method for treating a lithium-nickel-cobalt-containing material according to a first aspect of the present invention comprises: a leaching step of adding an acidic solution containing an inorganic acid to a lithium-nickel-cobalt-containing material containing lithium, nickel, and cobalt to leach lithium, nickel, and cobalt into the acidic solution; a reduction-leaching step of adding a reducing agent to the acidic solution to reduce at least a portion of the high-valence nickel and cobalt to further leach lithium, nickel, and cobalt; a neutralization step of adding a neutralizing agent to the leaching step and the lithium-nickel-cobalt leachate obtained in the reduction-leaching step to produce a nickel-cobalt precipitate containing nickel and cobalt; a solid-liquid separation step of separating the lithium leachate from the nickel-cobalt precipitate after the neutralization step; and a nickel-cobalt recovery step of recovering nickel and cobalt from the nickel-cobalt precipitate.

[0008] The method for treating a lithium-nickel-cobalt-containing material according to aspect 1 of the present invention includes a leaching step of adding an acidic solution containing an inorganic acid to the lithium-nickel-cobalt-containing material to leach lithium, nickel, and cobalt into the acidic solution, and a reduction-leaching step of adding a reducing agent to the acidic solution to reduce at least a portion of the high-valence nickel and cobalt, thereby further leaching the nickel and cobalt. Therefore, even if a poorly soluble composite oxide is present in the lithium-nickel-cobalt-containing material, lithium, nickel, and cobalt can be stably leached. The method also includes a neutralization step in which a neutralizing agent is added to the lithium-nickel-cobalt leachate obtained in the leaching step and the reduction leaching step to produce a nickel-cobalt precipitate containing nickel and cobalt, and a solid-liquid separation step in which the lithium leachate is separated from the nickel-cobalt precipitate after the neutralization step.This allows separation into the lithium leachate and the nickel-cobalt precipitate, and lithium can be recovered as the lithium leachate, while nickel and cobalt can be efficiently recovered in the nickel-cobalt recovery step.

[0009] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 2 of the present invention is characterized in that, in the method for treating a lithium-nickel-cobalt-containing material according to Aspect 1 of the present invention, the inorganic acid used in the leaching step is one or more of sulfuric acid, hydrochloric acid, and nitric acid. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 2 of the present invention, since the inorganic acid used in the leaching step is one or more of sulfuric acid, hydrochloric acid, and nitric acid, lithium, nickel, and cobalt can be efficiently dissolved to obtain a lithium-nickel-cobalt leachate.

[0010] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 3 of the present invention is characterized in that, in the method for treating a lithium-nickel-cobalt-containing material according to Aspect 1 or Aspect 2 of the present invention, the neutralizing agent added in the neutralization step is one or more of calcium hydroxide, calcium oxide, and calcium carbonate. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 3 of the present invention, the neutralizing agent added in the neutralization step is one or more of calcium hydroxide, calcium oxide, and calcium carbonate. Therefore, fluorine derived from the electrolyte of a lithium-ion battery dissolved in the leaching step can be removed as calcium fluoride to obtain a lithium leachate with a high lithium purity, and a nickel-cobalt precipitate containing nickel and cobalt can be efficiently produced.

[0011] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 4 of the present invention is characterized in that the pH in the leaching step is within the range of 1.5 to 2.0 inclusive, in the method for treating a lithium-nickel-cobalt-containing material according to any one of Aspects 1 to 3 of the present invention. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 4 of the present invention, the pH in the leaching step is within the range of 1.5 to 2.0 inclusive, so that lithium, nickel, and cobalt can be efficiently leached from the lithium-nickel-cobalt-containing material into the acidic solution.

[0012] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 5 of the present invention is characterized in that the reducing agent used in the reduction leaching step is hydrogen peroxide in the method for treating a lithium-nickel-cobalt-containing material according to any one of Aspects 1 to 4 of the present invention. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 5 of the present invention, the reducing agent used in the reduction leaching step is hydrogen peroxide, so that lithium, nickel, and cobalt can be reliably leached even if a poorly soluble composite oxide is present in the lithium-nickel-cobalt-containing material.

[0013] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 6 of the present invention is characterized in that the leaching step and the reduction leaching step are carried out simultaneously in the method for treating a lithium-nickel-cobalt-containing material according to any one of Aspects 1 to 5 of the present invention. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 6 of the present invention, by adding a reducing agent to an acidic solution and carrying out the leaching step and the reduction leaching step simultaneously, lithium, nickel, and cobalt can be leached from the lithium-nickel-cobalt-containing material more efficiently.

[0014] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 7 of the present invention is the method for treating a lithium-nickel-cobalt-containing material according to any one of Aspects 1 to 6 of the present invention, characterized in that the nickel-cobalt recovery step comprises a second leaching step of leaching a nickel-cobalt precipitate in an acidic solution containing an inorganic acid to obtain a nickel-cobalt leachate, and a second solid-liquid separation step of separating the nickel-cobalt leachate from a solid component. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 7 of the present invention, the nickel-cobalt recovery step comprises the second leaching step of leaching a nickel-cobalt precipitate in an acidic solution containing an inorganic acid to obtain a nickel-cobalt leachate, and a second solid-liquid separation step of separating the nickel-cobalt leachate from a solid component, thereby enabling reliable and efficient recovery of cobalt and nickel.

[0015] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 8 of the present invention is the method for treating a lithium-nickel-cobalt-containing material according to any one of Aspects 1 to 7 of the present invention, characterized in that nickel-cobalt sulfides are recovered by adding a sulfurizing agent to the nickel-cobalt leachate obtained in the second solid-liquid separation step. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 8 of the present invention, nickel-cobalt sulfides are recovered by adding a sulfurizing agent to the nickel-cobalt leachate obtained in the second solid-liquid separation step, so that cobalt and nickel can be recovered stably and efficiently.

[0016] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 9 of the present invention is the method for treating a lithium-nickel-cobalt-containing material according to any one of Aspects 1 to 8 of the present invention, characterized in that a reducing agent is added after or simultaneously with the second leaching step. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 9 of the present invention, since a reducing agent is added after or simultaneously with the second leaching step, cobalt and nickel can be further leached, and cobalt and nickel can be recovered more efficiently.

[0017] A method for treating a lithium-nickel-cobalt-containing material according to Aspect 10 of the present invention is the method for treating a lithium-nickel-cobalt-containing material according to Aspect 9 of the present invention, characterized in that heating is not performed when the reducing agent is added in the reduction leaching step, and heating is performed when the reducing agent is added in the second leaching step. According to the method for treating a lithium-nickel-cobalt-containing material according to Aspect 10 of the present invention, heating is not performed when the reducing agent is added in the reduction leaching step, but heating is performed when the reducing agent is added in the second leaching step. This may reduce consumption of the reducing agent in the reduction leaching step and enable efficient separation of nickel-cobalt and lithium.

[0018] According to the present invention, it is possible to provide a method for treating a lithium-nickel-cobalt-containing material that can efficiently recover valuable metals such as lithium, nickel, and cobalt from a lithium-nickel-cobalt-containing material that contains lithium, cobalt, and nickel.

[0019] FIG. 1 is a flow diagram showing a method for treating a lithium-nickel-cobalt-containing material according to an embodiment of the present invention.

[0020] An example of an embodiment of the present invention will be described below.

[0021] The method for treating a lithium-nickel-cobalt-containing material according to this embodiment is for recovering valuable metals such as lithium, nickel, and cobalt from a lithium-nickel-cobalt-containing material containing lithium, cobalt, and nickel. In this embodiment, the target lithium-nickel-cobalt-containing material is waste lithium-ion battery powder (so-called black mass) obtained by firing and / or pulverizing used lithium-ion batteries, or defective products (so-called black powder) generated in the manufacturing process of positive electrode materials for secondary batteries, etc.

[0022] In addition, the above-mentioned waste lithium-ion battery powder (black mass) and defective products (black powder) include: (a) lithium, nickel, and cobalt combined (for example, LiNiO ２ , LiCoO ２ etc.), (b) those derived from the electrolyte (e.g., Li ２ CO ３ (c) Others (e.g., LiAlO ２ , metallic Co, metallic Ni, NiO, CoO, etc.) are mixed. Here, (b) those derived from the electrolyte (for example, Li ２ CO ３ (a) lithium combined with nickel and cobalt (e.g., LiNiO ２ , LiCoO ２ (c) Others (e.g., LiAlO ２ , metallic Co, metallic Ni, NiO, CoO, etc.) are hardly soluble in acidic solutions.

[0023] The method for treating a lithium-nickel-cobalt-containing material according to this embodiment includes at least a leaching step S01, a reduction leaching step S02, a neutralization step S03, a solid-liquid separation step S04, and a nickel-cobalt recovery step S05, as shown in Fig. 1. In this embodiment, the nickel-cobalt recovery step S05 includes a second leaching step S51 and a second solid-liquid separation step S52.

[0024] (Leaching Step S01) In this leaching step S01, lithium-nickel-cobalt-containing material, such as waste lithium-ion battery powder, is immersed in an acidic solution to leach lithium, nickel, and cobalt into the acidic solution, thereby obtaining a lithium-nickel-cobalt leachate. The acidic solution may be, for example, an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid, either singly or in combination. In this embodiment, sulfuric acid is used as the acid.

[0025] In this embodiment, the lithium-nickel-cobalt-containing material is mixed with an acidic solution and stirred (stirring time: 1 hour to 24 hours) to dissolve the lithium, nickel, and cobalt in the lithium-nickel-cobalt-containing material, thereby obtaining a lithium-nickel-cobalt leachate. Here, in this embodiment, the pH of the lithium-nickel-cobalt leachate in the leaching step S01 is preferably in the range of 1.5 to 2.0.

[0026] (Reduction-leaching step S02) In this reduction-leaching step S02, a reducing agent is added to the acidic solution to reduce at least a portion of the high-valence nickel and cobalt, and the nickel and cobalt are further leached into the acidic solution. In the lithium-nickel-cobalt-containing material, complex compounds containing nickel and cobalt that are difficult to dissolve in acid may exist. In such complex oxides, nickel and cobalt exist in high-valence states such as trivalent and tetravalent. Here, by adding a reducing agent to the acidic solution, the trivalent and tetravalent nickel and cobalt are reduced to divalent, thereby facilitating their leaching into the acidic solution. That is, (a) lithium, nickel, and cobalt combined (e.g., LiNiO) contained in waste lithium-ion battery powder (black mass) and the like is extracted. ２ , LiCoO ２ In the reduction leaching step S02, (c) other (e.g., LiAlO ２Since there is no need to dissolve the reducing agent (e.g., metallic Co, metallic Ni, NiO, CoO, etc.), the reducing agent is not heated when added, and the reducing agent is (a) a compound of lithium, nickel, and cobalt (e.g., LiNiO ２ , LiCoO ２ It is preferable to effectively use it to dissolve the above-mentioned substances.

[0027] Examples of the reducing agent include hydrogen peroxide, sulfur dioxide, and sodium bisulfite. In this embodiment, hydrogen peroxide is used as the reducing agent. The mass ratio of the reducing agent to the acidic solution is preferably 0.01 to 1.0. A mass ratio of the reducing agent to the acidic solution of 0.01 or more can sufficiently leach nickel and cobalt. A mass ratio of the reducing agent to the acidic solution of 1.0 or less can prevent residual reducing agent from being added. The mass ratio of the reducing agent to the acidic solution is more preferably 0.1 to 0.5. The leaching step S01 and the reduction leaching step S02 can also be performed simultaneously. The temperature of the acidic solution during reduction leaching is preferably 50°C to 80°C, more preferably 60°C to 75°C.

[0028] (Neutralization Step S03) Next, a neutralizing agent is added to the lithium-nickel-cobalt leachate obtained in the reduction leaching step S02 to produce a nickel-cobalt precipitate containing nickel and cobalt. In this embodiment, the neutralizing agent added in the neutralization step S03 is preferably one or more of calcium hydroxide, calcium oxide, and calcium carbonate. There are no particular restrictions on the pH in the neutralization step S03, but it is preferably within the range of 8 to 12.

[0029] (Solid-liquid separation step S04) In this solid-liquid separation step S04, the nickel-cobalt precipitate produced in the neutralization step S03 is separated from the lithium leachate. As a method for separating the nickel-cobalt precipitate from the lithium leachate, a solid-liquid separation method such as gravity settling, centrifugal separation, or filter cloth filtration using a filter press or the like can be used.

[0030] (Nickel / Cobalt Recovery Step S05) In this nickel / cobalt recovery step S05, nickel and cobalt are recovered from the nickel / cobalt precipitate separated in the solid-liquid separation step S04. In this embodiment, as shown in Figure 1, the nickel / cobalt recovery step S05 includes a second leaching step S51 and a second solid-liquid separation step S52.

[0031] In the second leaching step S51, the nickel-cobalt precipitate separated in the solid-liquid separation step S04 is leached in an acidic solution containing an inorganic acid to obtain a nickel-cobalt leachate. The inorganic acid used in the second leaching step S51 can be one or more of sulfuric acid, hydrochloric acid, and nitric acid. Heating is preferably performed in the second leaching step S01. Specifically, the leaching temperature is preferably 50°C to 80°C, and more preferably 60°C to 75°C. Reduction leaching may be performed after or simultaneously with the second leaching step S51 by adding a reducing agent. In this case, heating is preferably not performed in the reduction leaching step S02 but is performed in the second leaching step S51. This may allow for efficient separation of nickel-cobalt and lithium while minimizing the consumption of reducing agent in the reduction leaching step S02. The reason why nickel / cobalt and lithium can be separated efficiently in this case is that in the reduction leaching step S02 in which lithium is leached into an acidic solution, the amount of reducing agent consumed in leaching nickel and cobalt that do not need to be leached is suppressed, the amounts of nickel and cobalt leached into the lithium leachate are suppressed, and further, in the nickel / cobalt recovery step S05, more reducing agent can be consumed for leaching nickel and cobalt.

[0032] Next, in the second solid-liquid separation step S52, the nickel-cobalt leachate is separated from the solid components, and cobalt and nickel are recovered as a nickel-cobalt leachate. The nickel-cobalt leachate can be separated from the solid components by a solid-liquid separation method such as gravity settling, centrifugal separation, or filter cloth filtration using a filter press or the like. Alternatively, a sulfiding agent may be added to the nickel-cobalt leachate to recover nickel-cobalt sulfides.

[0033] By carrying out these steps, lithium is recovered as a lithium leachate, and cobalt and nickel are recovered as a nickel-cobalt leachate from the lithium-nickel-cobalt-containing material.

[0034] The method for treating a lithium-nickel-cobalt-containing material according to this embodiment, configured as described above, includes a leaching step S01 in which an acidic solution containing an inorganic acid is added to leach lithium, nickel, and cobalt into the acidic solution, and a reduction-leaching step S02 in which a reducing agent is added to the acidic solution to reduce at least a portion of the high-valence nickel and cobalt, thereby further leaching the nickel and cobalt. Therefore, even if the lithium-nickel-cobalt-containing material contains poorly soluble composite oxides, the trivalent and tetravalent nickel and cobalt, which are difficult to dissolve in the reducing agent, can be converted to divalent nickel and cobalt, and the lithium, nickel, and cobalt can be stably leached into the acidic solution.

[0035] The process includes a neutralization step S03 in which a neutralizing agent is added to the lithium-nickel-cobalt leachate obtained in the leaching step S01 and the reduction leaching step S02 to produce a nickel-cobalt precipitate containing nickel and cobalt, a solid-liquid separation step S04 in which the lithium leachate is separated from the nickel-cobalt precipitate after the neutralization step S03, and a nickel-cobalt recovery step S05 in which nickel and cobalt are recovered from the nickel-cobalt precipitate.As a result, the lithium leachate can be separated from the nickel-cobalt precipitate, and lithium can be recovered as the lithium leachate, while nickel and cobalt can be efficiently recovered from the nickel-cobalt precipitate.

[0036] In this embodiment, when the inorganic acid used in the leaching step S01 is one or more of sulfuric acid, hydrochloric acid, and nitric acid, the lithium, nickel, and cobalt in the lithium-nickel-cobalt-containing material can be dissolved to efficiently produce a lithium-nickel-cobalt leachate.

[0037] In this embodiment, when the neutralizing agent added in the neutralization step S03 is one or more of calcium hydroxide, calcium oxide, and calcium carbonate, fluorine derived from the electrolyte of the lithium ion battery dissolved in the leaching step can be removed as calcium fluoride to obtain a lithium leachate with high lithium purity, and a nickel-cobalt precipitate containing nickel and cobalt can be efficiently produced.

[0038] In this embodiment, when the pH in the leaching step S01 is set within the range of 1.5 or more and 2.0 or less, lithium, nickel, and cobalt can be efficiently leached from the lithium-nickel-cobalt-containing material into the acidic solution.

[0039] In this embodiment, when the reducing agent used in the reduction leaching step S02 is hydrogen peroxide, lithium, nickel, and cobalt can be reliably leached even if a poorly soluble composite oxide is present in the lithium-nickel-cobalt-containing material.

[0040] In this embodiment, when the leaching step S01 and the reduction leaching step S02 are carried out simultaneously, lithium, nickel, and cobalt can be leached more efficiently from the lithium-nickel-cobalt-containing material.

[0041] In the present embodiment, when the nickel-cobalt recovery step S05 includes a second leaching step S51 in which the nickel-cobalt precipitate is leached in an acidic solution containing an inorganic acid to obtain a nickel-cobalt leachate, and a second solid-liquid separation step S52 in which the nickel-cobalt leachate is separated from the solid component, cobalt and nickel can be reliably and efficiently recovered from the nickel-cobalt precipitate.

[0042] In the present embodiment, when a sulfiding agent is added to the nickel-cobalt leachate obtained in the second solid-liquid separation step S52 to recover nickel-cobalt sulfides, cobalt and nickel can be recovered stably and efficiently.

[0043] In this embodiment, if a reducing agent is added after or simultaneously with the second leaching step S51, cobalt and nickel can be further leached, and cobalt and nickel can be recovered more efficiently.

[0044] In this embodiment, if the reducing agent is not heated when added in the reduction leaching step S02 but is heated when added in the second leaching step S51, it may be possible to reduce consumption of the reducing agent in the reduction leaching step S02 and efficiently separate nickel-cobalt and lithium.

[0045] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0046] The results of confirmation experiments conducted to confirm the effectiveness of the present invention will be described below.

[0047] Example 1: 47 vol.% sulfuric acid was added to 80 g of the black mass shown in Table 1 until the pH reached 2 or less (leaching step). Next, while adding aqueous hydrogen peroxide, 47 vol.% sulfuric acid was added at room temperature (20°C to 30°C; in this example, 25°C) until the pH reached 2 or less (reductive leaching step). The mass ratio of aqueous hydrogen peroxide (reducing agent) to sulfuric acid (acidic solution) was 0.6. Next, aqueous calcium hydroxide solution was added to adjust the pH to 9.5 or more to obtain a slurry (neutralization step). This slurry was subjected to solid-liquid separation (solid-liquid separation step). The resulting lithium leachate and nickel-cobalt precipitate were subjected to elemental analysis by ICP. Next, 47 vol.% sulfuric acid was added to the nickel-cobalt precipitate at room temperature until the pH reached 2.0 or less (second leaching step). The slurry obtained in the second leaching step was subjected to solid-liquid separation (second solid-liquid separation step). The resulting nickel-cobalt leachate and solid components were subjected to elemental analysis by ICP.

[0048] The Li leaching rate (%) was calculated from the results of the above elemental analysis using the following formula. The calculation results are shown in Table 1. Li leaching rate (%) = [amount of Li leached in the first leaching step (g) / (amount of Li leached in the first leaching step (g) + amount of Li leached in the second leaching step (g) + amount of Li in the residue of the second leaching step (g))] × 100

[0049] Furthermore, the Co leaching rate (%) was calculated from the results of the above elemental analysis using the following formula. The calculation results are shown in Table 1. Co leaching rate (%) = [amount of Co leached in the second leaching step (g) / (amount of Co leached in the first leaching step (g) + amount of Co leached in the second leaching step (g) + amount of Co in the residue of the second leaching step (g))] × 100

[0050] Furthermore, the Ni leaching rate (%) was calculated from the results of the above elemental analysis using the following formula. The calculation results are shown in Table 1. Ni leaching rate (%) = [amount of Ni leached in the second leaching step (g) / (amount of Ni leached in the first leaching step (g) + amount of Ni leached in the second leaching step (g) + amount of Ni in the residue of the second leaching step (g))] × 100

[0051] Example 2: 47 vol% sulfuric acid was added to 80 g of the black mass shown in Table 2 until the pH reached 2 or less (leaching step). Next, while adding hydrogen peroxide solution, the temperature was set to 60°C, and 47 vol% sulfuric acid was added until the pH reached 2 or less (reductive leaching step). The mass ratio of hydrogen peroxide solution (reducing agent) to sulfuric acid (acidic solution) was 0.4. Next, calcium hydroxide solution was added to adjust the pH to 9.5 or more to obtain a slurry (neutralization step). This slurry was subjected to solid-liquid separation (first solid-liquid separation step). The obtained lithium leachate and nickel-cobalt precipitate were subjected to elemental analysis by ICP. The temperature was set to 60°C, and 47 vol% sulfuric acid was added to the nickel-cobalt precipitate until the pH reached 2.0 or less (second leaching step). The slurry obtained in the second leaching step was subjected to solid-liquid separation (second solid-liquid separation step). The resulting nickel-cobalt leachate and solid components were subjected to elemental analysis by ICP. The leaching rates (%) of Li, Co, and Ni were calculated in the same manner as in Example 1. The results are shown in Table 2.

[0052] Comparative Example: 47 vol% sulfuric acid was added to 80 g of the black mass shown in Table 3 at room temperature until the pH reached 2 or less (leaching step). Next, a calcium hydroxide aqueous solution was added to adjust the pH to 9.5 or more (neutralization step). The slurry obtained in the neutralization step was subjected to solid-liquid separation (first solid-liquid separation step). The resulting lithium leachate and nickel-cobalt precipitate were subjected to elemental analysis by ICP. 47% sulfuric acid was added to the nickel-cobalt precipitate at room temperature until the pH reached 2.0 or less (second leaching step). The slurry obtained in the second leaching step was subjected to solid-liquid separation (second solid-liquid separation step). The resulting nickel-cobalt leachate and solid components were subjected to elemental analysis by ICP. The Li leaching rate (%), Co leaching rate (%), and Ni leaching rate (%) were calculated in the same manner as in Example 1. The calculation results are shown in Table 3.

[0053]

[0054]

[0055]

[0056] In Examples 1 and 2, in which the reduction leaching step was performed, the leaching rates of Li, Co, and Ni were improved compared to the comparative example in which the reduction leaching step was not performed, confirming that lithium, nickel, and cobalt can be efficiently separated and recovered from a lithium-nickel-cobalt-containing material containing lithium, cobalt, and nickel. Furthermore, in Example 2, in which the temperature during leaching was set to 60°C, the leaching rates of Li, Co, and Ni were further improved compared to Example 1.

[0057] As a result of the above confirmatory experiments, it was confirmed that the present invention can provide a method for treating a lithium-nickel-cobalt-containing material that can efficiently recover valuable metals such as lithium, nickel, and cobalt from a lithium-nickel-cobalt-containing material that contains lithium, cobalt, and nickel.

[0058] According to the present invention, it is possible to provide a method for treating a lithium-nickel-cobalt-containing material that can efficiently recover valuable metals such as lithium, nickel, and cobalt from the lithium-nickel-cobalt-containing material.

Claims

1. A method for treating a lithium-nickel-cobalt-containing material, comprising: a leaching step of adding an acidic solution containing an inorganic acid to a lithium-nickel-cobalt-containing material containing lithium, nickel, and cobalt, thereby leaching lithium, nickel, and cobalt into the acidic solution; a reduction-leaching step of adding a reducing agent to the acidic solution to reduce at least a portion of the high-valence nickel and cobalt, thereby further leaching lithium, nickel, and cobalt; a neutralization step of adding a neutralizing agent to the lithium-nickel-cobalt leachate obtained in the leaching step and the reduction-leaching step, thereby producing a nickel-cobalt precipitate containing nickel and cobalt; a solid-liquid separation step of separating the lithium leachate from the nickel-cobalt precipitate after the neutralization step; and a nickel-cobalt recovery step of recovering nickel and cobalt from the nickel-cobalt precipitate.

2. The method for treating lithium-nickel-cobalt-containing material according to claim 1, characterized in that the inorganic acid used in the leaching step is one or more of sulfuric acid, hydrochloric acid, and nitric acid.

3. A method for treating lithium-nickel-cobalt-containing material as described in claim 1, characterized in that the neutralizing agent added in the neutralization step is one or more of calcium hydroxide, calcium oxide, and calcium carbonate.

4. The method for treating a lithium-nickel-cobalt-containing material according to claim 1, characterized in that the pH in the leaching step is in the range of 1.5 to 2.

0.

5. The method for treating a lithium-nickel-cobalt-containing material according to claim 1, wherein the reducing agent used in the reduction leaching step is hydrogen peroxide.

6. The method for treating a lithium-nickel-cobalt-containing material according to claim 1, wherein the leaching step and the reduction leaching step are carried out simultaneously.

7. The method for treating a lithium-nickel-cobalt-containing material according to claim 1, characterized in that the nickel-cobalt recovery process comprises a second leaching process in which the nickel-cobalt precipitate is leached in an acidic solution containing an inorganic acid to obtain a nickel-cobalt leachate, and a second solid-liquid separation process in which the nickel-cobalt leachate is separated from the solid components.

8. A method for treating a lithium-nickel-cobalt-containing material according to claim 7, characterized in that a sulfiding agent is added to the nickel-cobalt leachate obtained in the second solid-liquid separation step to recover nickel-cobalt sulfides.

9. The method for treating a lithium-nickel-cobalt-containing material according to claim 8, characterized in that a reducing agent is added after or simultaneously with the second leaching step.

10. A method for treating lithium-nickel-cobalt-containing material as described in claim 9, characterized in that the reducing agent is not heated when added in the reduction leaching process, but is heated when added in the second leaching process.

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