WO2025249461A1 - Treatment method for lithium/nickel/cobalt-containing material - Google Patents

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

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 on May 31, 2024, the contents of which are incorporated herein by reference.

In recent years, lithium has been recovered from crushed lithium-ion batteries and reused. When recovering lithium from lithium-ion batteries, it is common to use recycled raw materials, such as waste lithium-ion battery powder (known as black mass) obtained by firing and/or crushing used lithium-ion batteries, or defective products generated during the secondary battery manufacturing process (known as black powder).
Here, the above-mentioned waste lithium-ion battery powder contains metals other than lithium, such as nickel and cobalt, and therefore, techniques for recovering nickel and cobalt from waste lithium-ion battery powder have been proposed.

For example, Patent Document 1 proposes a technology for recovering lithium by leaching battery slag 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 in which lithium ion secondary batteries are crushed and classified to obtain an electrode material containing cobalt and nickel, this electrode material is immersed in a treatment solution containing sulfuric acid and hydrogen peroxide to produce a leachate, copper is separated from this leachate to obtain an eluate containing cobalt and nickel, an alkali metal hydroxide is added to this eluate to adjust the pH, a hydrogen sulfide compound is added, and the mixture is stirred and subjected to solid-liquid separation to separate the material into cobalt sulfide and nickel sulfide and a residual solution containing lithium.

Japanese Patent Application Publication No. 2019-160429 (A) Japanese Patent Application Publication No. 2022-042982 (A)

Incidentally, waste lithium-ion battery powder obtained by firing 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, in the method disclosed in Patent Document 2, an electrode material is immersed in a treatment solution containing sulfuric acid and hydrogen peroxide to obtain a leachate. This makes it possible to dissolve cobalt and nickel, but this leachate also contains lithium, which poses a problem in that it is not possible to efficiently recover lithium, nickel, and cobalt, respectively.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a method for treating lithium-nickel-cobalt-containing materials that can efficiently recover valuable metals such as lithium, nickel, and cobalt from lithium-nickel-cobalt-containing materials that contain lithium, cobalt, and nickel.

In order to solve the above problems, the method for treating a lithium-nickel-cobalt-containing material of aspect 1 of the present invention is characterized by comprising: a leaching step in which an acidic solution containing an inorganic acid is added 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 in which a reducing agent is added to the acidic solution to reduce at least a portion of the high-valence nickel and cobalt and further leach lithium, nickel, and cobalt; a neutralization step in which a neutralizing agent is added 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 in which the lithium leachate and the nickel-cobalt precipitate are separated after the neutralization step; and a nickel-cobalt recovery step in which nickel and cobalt are recovered from the nickel-cobalt precipitate.

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 allows lithium to be recovered as the lithium leachate, while nickel and cobalt to be efficiently recovered in the nickel-cobalt recovery step.

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

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 of 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 high lithium purity, and a nickel-cobalt precipitate containing nickel and cobalt can be efficiently produced.

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

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

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

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 of Aspect 7 of the present invention, the nickel-cobalt recovery step includes a second leaching step of leaching the 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 making it possible to recover cobalt and nickel reliably and efficiently.

A method for treating a lithium-nickel-cobalt-containing material according to an eighth aspect of the present invention is the method for treating a lithium-nickel-cobalt-containing material according to any one of the first to seventh aspects of the present invention, 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.
According to the method for treating a lithium-nickel-cobalt-containing material of Aspect 8 of the present invention, a sulfiding agent is added to the nickel-cobalt leachate obtained in the second solid-liquid separation step to recover nickel-cobalt sulfides, so that cobalt and nickel can be recovered stably and efficiently.

A ninth aspect of the present invention is a method for treating a lithium-nickel-cobalt-containing material, which is the method for treating a lithium-nickel-cobalt-containing material according to any one of the first to eighth aspects 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 of Aspect 9 of the present invention, a reducing agent is added after or simultaneously with the second leaching step, so that cobalt and nickel can be further leached, and cobalt and nickel can be recovered more efficiently.

A tenth aspect of the present invention is a method for treating a lithium-nickel-cobalt-containing material according to the ninth aspect of the present invention, characterized in that 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.
According to the method for treating a lithium-nickel-cobalt-containing material of Aspect 10 of the present invention, the reducing agent is not heated when added in the reduction leaching step, but is heated when 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.

The present invention provides a method for treating lithium-nickel-cobalt-containing materials that can efficiently recover valuable metals such as lithium, nickel, and cobalt from lithium-nickel-cobalt-containing materials containing lithium, cobalt, and nickel.

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.

Below, an example of an embodiment of the present invention is described.

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 that contains lithium, cobalt, and nickel.
In this embodiment, the lithium-nickel-cobalt-containing material to be treated 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.

The above-mentioned waste lithium-ion battery powder (black mass) and defective products (black powder) contain (a) compounds in which lithium is combined with nickel and cobalt (e.g., _LiNiO2 , _LiCoO2 , etc.), (b) compounds derived from the electrolyte (e.g., _{Li2CO3 , etc.} ), and (c) other compounds (e.g., _LiAlO2 , metallic Co, metallic Ni, NiO, CoO, etc.).
Here, (b) those derived from the electrolyte (e.g., _Li2CO3 , _etc. ) are easily soluble in acidic solutions, but (a) those in which lithium is combined with nickel and cobalt (e.g., _LiNiO2 , _LiCoO2 , etc.) tend to be less soluble in acidic solutions because nickel and cobalt are trivalent and tetravalent, respectively. Note that (c) others (e.g., _LiAlO2 , metallic Co, metallic Ni, NiO, CoO, etc.) are hardly soluble in acidic solutions.

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.

(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 acid 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.

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

(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.
Lithium-nickel-cobalt-containing materials may contain complex compounds containing nickel and cobalt that are difficult to dissolve in acid. 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, trivalent and tetravalent nickel and cobalt are reduced to divalent nickel and cobalt, thereby facilitating their leaching into the acidic solution. That is, this promotes the dissolution of (a) lithium-nickel-cobalt combinations (e.g., _LiNiO2 , _LiCoO2 , etc.) contained in the waste lithium-ion battery powder (black mass), etc., and makes it possible to further leach nickel and cobalt into the acidic solution.
In the reduction leaching step S02, since there is no need to dissolve (c) others (e.g., LiAlO ₂ , metallic Co, metallic Ni, NiO, CoO, etc.), it is preferable not to heat the reducing agent when adding it, but to effectively use the reducing agent to dissolve (a) compounds of lithium, nickel, and cobalt combined together (e.g., LiNiO ₂ , LiCoO _{2 ,} etc.).

Here, examples of the reducing agent that can be used include hydrogen peroxide, sulfur dioxide, sodium hydrogen sulfite, etc. In this embodiment, hydrogen peroxide is used as the reducing agent.
The mixing ratio of the reducing agent to the acidic solution is preferably 0.01 or more and 1.0 or less by mass. By setting the mixing ratio of the reducing agent to the acidic solution to 0.01 or more by mass, nickel and cobalt can be sufficiently leached. Furthermore, by setting the mixing ratio of the reducing agent to the acidic solution to 1.0 or less, it is possible to prevent the added reducing agent from remaining. The mixing ratio of the reducing agent to the acidic solution is more preferably 0.1 or more and 0.5 or less by mass.
The leaching step S01 and the reduction leaching step S02 can also be carried out simultaneously.
The temperature of the acidic solution during reduction leaching is preferably 50°C or higher and 80°C or lower, and more preferably 60°C or higher and 75°C or lower.

(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, it is preferable to use one or more of calcium hydroxide, calcium oxide, and calcium carbonate as the neutralizing agent added in the neutralization step S03.
The pH in the neutralization step S03 is not particularly limited, but is preferably within the range of 8 or more and 12 or less.

(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.

(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.

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.
Note that a reducing agent may be added after or simultaneously with the second leaching step S51 to perform reduction leaching. In this case, it is preferable not to heat the reduction leaching step S02 but to heat the second leaching step S51. It is possible to efficiently separate nickel/cobalt and lithium by suppressing consumption of the reducing agent in the reduction leaching step S02. The reason why nickel/cobalt and lithium can be efficiently separated 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, and the amounts of nickel and cobalt leached into the lithium leachate are suppressed. Furthermore, more reducing agent can be consumed for leaching nickel and cobalt in the nickel/cobalt recovery step S05.

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 the nickel-cobalt leachate. The nickel-cobalt leachate can be separated from the solid components by a solid-liquid separation method such as gravity settling, centrifugation, or filter cloth filtration using a filter press or the like.
It is also possible to add a sulfiding agent to the nickel-cobalt leachate to recover nickel-cobalt sulfides.

By carrying out each of these steps, lithium is recovered from the lithium-nickel-cobalt-containing material as lithium leachate, and cobalt and nickel are recovered as nickel-cobalt leachate.

The method for treating lithium-nickel-cobalt-containing material of 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 sparingly soluble composite oxides, the trivalent and tetravalent nickel and cobalt, which are difficult to dissolve in the reducing agent, can be converted to divalent form, and lithium, nickel, and cobalt can be stably leached into the acidic solution.

The system also 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. This allows the lithium leachate to 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.

In this embodiment, if 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.

In this embodiment, if 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.

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

In this embodiment, when hydrogen peroxide is used as the reducing agent in the reduction leaching step S02, lithium, nickel, and cobalt can be reliably leached even if insoluble composite oxides are present in the lithium-nickel-cobalt-containing material.

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 even more efficiently from the lithium-nickel-cobalt-containing material.

In this embodiment, when the nickel-cobalt recovery process S05 includes a second leaching process 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 process S52 in which the nickel-cobalt leachate is separated from the solid components, cobalt and nickel can be reliably and efficiently recovered from the nickel-cobalt precipitate.

In this embodiment, if 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.

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, allowing for more efficient recovery of cobalt and nickel.

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.

The above describes an embodiment of the present invention, but the present invention is not limited to this and can be modified as appropriate within the scope of the technical concept of the invention.

Below, we will explain the results of the confirmation experiments conducted to confirm the effectiveness of this invention.

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 the hydrogen peroxide solution, 47 vol% sulfuric acid was added at room temperature (20°C to 30°C, 25°C in this example) so that the pH was 2 or less (reductive leaching step). The mixing ratio of hydrogen peroxide solution (reducing agent) to sulfuric acid (acidic solution) was 0.6 by mass.
Next, an aqueous calcium hydroxide solution was added to adjust the pH to 9.5 or higher, thereby obtaining 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 to adjust the pH to 2.0 or less (second leaching step).
Next, the slurry obtained in the second leaching step was subjected to solid-liquid separation (second solid-liquid separation step). The obtained nickel-cobalt leachate and solid components were subjected to elemental analysis by ICP.

The leaching rate (%) of Li 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

Furthermore, from the results of the above elemental analysis, the Co leaching rate (%) was calculated 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

Furthermore, from the results of the above elemental analysis, the Ni leaching rate (%) was calculated 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

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 the hydrogen peroxide solution, the temperature was set to 60°C, and 47 vol% sulfuric acid was added so that the pH was 2 or less (reduction leaching step). Note that the mixing ratio of the hydrogen peroxide solution (reducing agent) to the sulfuric acid (acidic solution) was 0.4 by mass.
Next, an aqueous calcium hydroxide solution was added to adjust the pH to 9.5 or higher, thereby obtaining a slurry (neutralization step).
This slurry 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.
The temperature of the nickel-cobalt precipitate was set to 60° C., and then 47 vol % sulfuric acid was added to the precipitate to adjust the pH to 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 obtained 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 calculation results are shown in Table 2.

(Comparative Example)
To 80 g of the black mass shown in Table 3, 47 vol % sulfuric acid was added at room temperature until the pH reached 2 or less (leaching step).
Next, an aqueous solution of calcium hydroxide was added to adjust the pH to 9.5 or higher (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.
To the nickel-cobalt precipitate, 47% sulfuric acid was added at room temperature to adjust the pH to 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 calculation results are shown in Table 3.

In Examples 1 and 2, in which the reduction leaching step was carried out, the leaching rates of Li, Co, and Ni were improved compared to the comparative example in which the reduction leaching step was not carried out, and it was confirmed that lithium, nickel, and cobalt could be efficiently separated and recovered from the 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, it was confirmed that the leaching rates of Li, Co, and Ni were further improved compared to Example 1.

The results of the above confirmation experiments confirmed that the present invention can provide a method for treating lithium-nickel-cobalt-containing materials that can efficiently recover valuable metals such as lithium, nickel, and cobalt from lithium-nickel-cobalt-containing materials containing lithium, cobalt, and nickel.

The present invention makes it possible to provide a method for processing lithium-nickel-cobalt-containing materials that enables the efficient recovery of valuable metals such as lithium, nickel, and cobalt from lithium-nickel-cobalt-containing materials.

Claims (10)

a leaching step of adding an acidic solution containing an inorganic acid to a lithium-nickel-cobalt-containing material containing lithium, nickel, and cobalt, and leaching lithium, nickel, and cobalt into the acidic solution;
a reduction leaching step 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 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 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;
a nickel-cobalt recovery step of recovering nickel and cobalt from the nickel-cobalt precipitate;
A method for treating a lithium-nickel-cobalt-containing material, comprising: The method for treating lithium-nickel-cobalt-containing material according to claim 1, characterized in that the inorganic acid used in the leaching process is one or more of sulfuric acid, hydrochloric acid, and nitric acid. The method for treating lithium-nickel-cobalt-containing materials according to 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. The method for treating lithium-nickel-cobalt-containing material according to claim 1, characterized in that the pH during the leaching process is in the range of 1.5 to 2.0. The method for treating lithium-nickel-cobalt-containing material described in claim 1, characterized in that the reducing agent used in the reduction leaching process is hydrogen peroxide. The method for treating lithium-nickel-cobalt-containing material according to claim 1, characterized in that the leaching process and the reduction leaching process are carried out simultaneously. The method for treating lithium-nickel-cobalt-containing material described in claim 1, characterized in that the nickel-cobalt recovery process includes 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 solid components. The method for treating lithium-nickel-cobalt-containing material described in 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. The method for treating lithium-nickel-cobalt-containing material described in claim 8, characterized in that a reducing agent is added after or simultaneously with the second leaching step. The method for treating lithium-nickel-cobalt-containing material 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.