JP2010040458A - Lithium recovery method and metal-recovering method - Google Patents

Abstract

The present invention provides a lithium recovery method and other metal recovery methods capable of recovering lithium in a high yield without requiring complicated processing such as vacuum overheat treatment.
A lithium recovery method of the present invention includes a lithium ion secondary battery 1 including a positive electrode 11, a negative electrode 12, and a solid electrolyte 13 interposed between the positive electrode 11 and the negative electrode 12 and containing lithium (Li). A decomposition step for decomposition, a dissolution step for dissolving lithium contained in the solid electrolyte 13 taken out in the decomposition step, and a separation step for separating the lithium solution and the residue in which lithium is dissolved in the dissolution step are performed.
[Selection] Figure 1

Description

  The present invention relates to a lithium recovery method and a metal recovery method from a lithium ion secondary battery.

In recent years, lithium batteries, particularly lithium ion secondary batteries, are often used as batteries for portable electronic devices and hybrid cars. This is because the lithium ion secondary battery can be reduced in size, weight and capacity, and has high output and high energy density.
By the way, with the increase in demand for lithium ion secondary batteries, various recycling of the constituent materials has been studied. For example, Patent Document 1 discloses an electrode-constituting metal recovery method capable of recovering transition metals such as nickel and cobalt in a high yield. Patent Document 2 discloses a method for recovering metals, particularly copper, aluminum, iron and cobalt, and lithium carbonate from waste lithium ion batteries.

JP 2007-323868 A JP 2003-157913 A

However, in the conventional recovery methods described in Patent Document 1 and Patent Document 2, the main purpose is to recover rare metals such as nickel and cobalt in a high yield, and lithium recovery is particularly important. It was not regarded as important. For this reason, lithium was only obtained in a low yield at the final stage of the recovery process.
Moreover, in the conventional method, various metals were collect | recovered from the lithium ion secondary battery provided with the liquid electrolyte and the electrode containing lithium and a transition metal. For this reason, prior to a specific metal recovery step, a step (for example, vacuum heat treatment or the like) of decomposing or volatilizing the electrolytic solution and the organic solvent constituting the electrolyte is necessary.
In view of such problems and the like, the present invention aims to provide a lithium recovery method and other metal recovery methods capable of recovering lithium in a high yield without requiring complicated processing such as vacuum heat treatment. To do.

  The lithium recovery method of the present invention includes a lithium ion secondary battery comprising a positive electrode, a negative electrode, and a solid electrolyte containing lithium (Li) interposed between the positive electrode and the negative electrode, the positive electrode, the negative electrode, A decomposition step that decomposes into a solid electrolyte and other members, a dissolution step that dissolves lithium contained in the solid electrolyte taken out in the decomposition step, and a lithium solution and a residue in which the lithium is dissolved in the dissolution step And a separation step of separating.

  In the lithium recovery method of the present invention, the solid electrolyte is a sulfide-based fired body that is heat-treated using lithium sulfide and phosphorus sulfide as raw materials. In the melting step, the positive electrode, the negative electrode, and the electrolyte are washed with water. The lithium is preferably dissolved in water.

  In the lithium recovery method of the present invention, after the separation step, the pH of the lithium solution is adjusted to precipitate impurity metals other than the lithium, and the precipitate is separated to obtain a high-purity lithium solution. It is preferable to carry out a recovery step of adding a water-soluble carbonate to the high-purity lithium solution and recovering the generated lithium carbonate.

  In the metal recovery method of the present invention, the metal contained in the lithium ion secondary battery is obtained by performing at least one of the positive electrode, the negative electrode, and the residue as a material to be processed after performing the lithium recovery method described above. It is characterized by collect | recovering.

  The metal recovery method of the present invention includes an elution step for eluting the metal contained in the material to be treated by acid treatment, and a metal for treating the metal solution obtained in the elution step and recovering the generated precipitate. It is preferable to carry out the recovery step.

In the lithium recovery method of the present invention, lithium is recovered from the solid electrolyte. Therefore, lithium can be recovered in a high yield without requiring a complicated process such as vacuum heat treatment.
In the metal recovery method of the present invention, the conventional complicated lithium removal step can be omitted, so that the metal can be easily recovered.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the present embodiment.

[Configuration of lithium ion secondary battery]
FIG. 1 shows an outline of a cross section of a lithium ion secondary battery that is an object of the lithium recovery method of the present embodiment.
The lithium ion secondary battery 1 includes a positive electrode 11, a negative electrode 12, a solid electrolyte 13 that is interposed between the positive electrode 11 and the negative electrode 12 and contains lithium (Li), phosphorus (P), and sulfur (S). And a package (not shown).
The positive electrode 11 and the negative electrode 12 are made of, for example, stainless steel, gold, platinum, zinc, nickel, tin, aluminum, molybdenum, niobium, tantalum, tungsten, titanium, and alloys thereof, and sheets, foils thereof. , A net, a punching metal, an expanded metal or the like is used.
The solid electrolyte 13 is mainly composed of lithium element (Li), phosphorus element (P), and sulfur element (S). In particular, lithium sulfide (Li ₂ S) and phosphorus sulfide (P ₂ S ₅ ) are produced from a mixed raw material having a molar ratio of 65:35 to 75:25, and in particular, the mixed raw material is 150 in an inert gas atmosphere such as nitrogen. It is preferable that the glass is a sulfide-based glass that is a sulfide-based fired body that has been heat-treated at a temperature of from ℃ to 360 ° C. This composition ratio provides high lithium ion conductivity and facilitates lithium recovery.

[Recycling method of lithium ion secondary battery]
FIG. 2 shows an outline of the lithium recovery method and metal recovery method of the present embodiment.
The lithium recovery method and the metal recovery method constitute a recycling method for one lithium ion secondary battery 1 as a whole.

[Lithium recovery method]
In the lithium recovery method of this embodiment, as shown in FIG. 2, a decomposition step S101, a dissolution step S102, a separation step S103, a purification step S104, and a recovery step S105 are performed.

[Disassembly step S101]
The decomposition step S101 is a step of disassembling the used lithium ion secondary battery 1 collected from consumers or the like into members such as the positive electrode 11, the negative electrode 12, the solid electrolyte 13, and a package, and separating each member. In the recycling process of the conventional lithium ion secondary battery, in order to process the liquid electrolyte, a vacuum overheat treatment or the like is required. However, in the present embodiment, the lithium ion secondary battery 1 includes the solid electrolyte 13. No complicated electrolyte treatment is required.
In this embodiment, since the purpose is to recover lithium and other metals, as shown in FIG. 2, members containing metals such as the positive electrode 11, the negative electrode 12, and the solid electrolyte 13 are treated, and other members ( Packages, etc.) are separately recycled using an appropriate method.

[Dissolution Step S102]
The dissolution step S102 is a step of dissolving lithium contained in the solid electrolyte 13 taken out in the decomposition step S101. Although the dissolution method differs depending on the material of the solid electrolyte 13, for example, a method of washing with water and dissolving in water, a method of dissolving with an acid such as hydrochloric acid or oxalic acid, and the like can be mentioned.
However, since sulfide-based solid electrolyte and water react to generate hydrogen sulfide, if hydrogen sulfide is generated, it is necessary to recover the hydrogen sulfide with an alkaline solution (for example, sodium hydroxide solution). become.
In the composition of the solid electrolyte 13 of the present embodiment, lithium can be dissolved in water. For this reason, not only the solid electrolyte 13 but also the positive electrode 11 and the negative electrode 12 can be washed with water to dissolve lithium adhering to these electrodes. Since it is washed with water, there is an advantage that only the lithium can be recovered without eluting the metal of the electrode itself.

[Separation step S103]
Separation process S103 is a process which isolate | separates the lithium solution and lithium which melt | dissolved lithium in melt | dissolution process S102 by methods, such as filtration. Through this separation step S103, lithium is recovered in a high yield as a lithium solution.
Lithium contained in the lithium solution is used in an appropriate method and form in accordance with the recycling application. In this embodiment, as an example, the following purification step S104 and recovery step S105 are performed to generate high-purity lithium carbonate.
The residue separated in the separation step S103, and the positive electrode 11 and the negative electrode 12 are treated materials of a metal recovery method described later. Needless to say, the material to be treated may contain a member other than the residue and the positive electrode 11 and the negative electrode 12.

[Purification Step S104 and Recovery Step S105]
An outline of the purification step S104 and the recovery step S105 is shown in FIG.
In the purification step S104, as shown in FIG. 3, a pH adjuster is added to the lithium solution obtained in the separation step S103 to precipitate impurity metals other than lithium, and the precipitate is filtered to obtain a high-purity lithium solution. It is the process of obtaining. On the other hand, the recovery step S105 is a step of adding the water-soluble carbonate to the high purity lithium solution and recovering the generated lithium carbonate.
By employing the purification step S104 and the recovery step S105, the impurity metal can be removed and high-purity lithium can be recovered.
As such purification step S104 and recovery step S105, a general lithium purification and precipitation method can be used. Examples of the pH adjuster include hydrochloric acid and sodium hydroxide. Moreover, sodium carbonate etc. are mentioned as water-soluble carbonate.

[Metal recovery method]
As shown in FIG. 2, in the metal recovery method of this embodiment, after performing the above-described lithium recovery method, at least one of the positive electrode 11, the negative electrode 12, and the residue is processed as a material to be processed, and a lithium ion secondary The metal contained in the battery 1 is recovered.
By the metal recovery method, other metals can be recovered while recovering lithium in a high yield at an early stage. In addition, since the conventional complicated lithium removal step can be omitted, the metal can be easily recovered.
The metal recovery method is not particularly limited as long as the metal can be recovered from the material to be treated, and a conventional method can be appropriately used. In this embodiment, as shown in FIG. 2, elution is performed. Step S201 and metal recovery step S202 are performed.
The elution step S201 is a step of eluting the metal contained in the material to be processed by acid treatment. The metal recovery step S202 is a step of processing the metal solution obtained in the elution step S201 and recovering the generated precipitate.
In the elution step S201, once all the metal is eluted in the metal solution, various metals can be separated and recovered by sequentially precipitating and filtering each metal in the metal recovery step S202.
There is no restriction | limiting in particular as elution process S201 and metal collection | recovery process S202, A conventionally well-known thing can be utilized. For example, the method described in Patent Document 1 can be used. It is preferable to recover transition metals such as nickel and cobalt which are rare metals.
Furthermore, by adopting the elution step and the metal recovery step, various metals including lithium can be easily recovered simply by performing the conventional elution step and metal recovery step together with the lithium recovery method described above.

As described above, according to the lithium recovery method of the present embodiment, since lithium is recovered from the lithium ion secondary battery 1 provided with the solid electrolyte 13, an early stage without requiring complicated processing such as vacuum overheating. Can recover lithium in high yield. Further, according to the metal recovery method of the present embodiment, a complicated lithium removal step can be omitted and the metal can be easily recovered.
And as lithium ion secondary battery used as the collection | recovery object of lithium in this invention, since lithium is collect | recovered from the lithium ion secondary battery 1 provided with the solid electrolyte 13, in order to process electrolyte like the conventional collection method In addition, it is not necessary to perform a complicated process such as vacuum heat treatment, and the decomposition process can be performed immediately.
The solid electrolyte 13 contains a large amount of lithium responsible for electrical conduction, but usually does not contain other metals. For this reason, lithium can be recovered in a high yield as the lithium solution by carrying out the dissolution step and the separation step.
Here, in the present invention, unlike the conventional method of recovering lithium from the electrode, lithium can be recovered from the solid electrolyte 13 immediately after the decomposition step, so that it is an early stage with respect to the entire recycling process of the lithium ion secondary battery 1. Thus, lithium can be recovered in a high yield.
The solid electrolyte 13 is a sulfide-based fired body that is heat-treated using lithium sulfide and phosphorus sulfide as raw materials. In the melting step, the positive electrode 11, the negative electrode 12, and the solid electrolyte 13 are washed with water, and the lithium is washed with water. It is preferable to dissolve in. With such a configuration, lithium contained in the sulfide-based fired body can be dissolved in water, so that it adheres to the positive electrode 11 or the negative electrode 12 without dissolving other metals contained in the positive electrode 11 or the negative electrode 12. Recoverable lithium can be recovered.

[Modification]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment. Modifications and improvements within the scope of achieving the objects and effects of the present invention are included in the content of the present invention, and there is no problem with the specific structure and shape as other structures and shapes.
In the above-described embodiment, the lithium ion secondary battery 1 including the positive electrode 11, the negative electrode 12, the solid electrolyte 13, and the package is illustrated, but the present invention is not limited to this. For example, the lithium ion secondary battery 1 may include other members (a positive electrode current collector, a negative electrode current collector, etc.). In this case, about the member which contacts the solid electrolyte 13, it is preferable to wash with water by melt | dissolution process S102. Moreover, about the member containing a useful metal, it is preferable to set it as the to-be-processed material of a metal recovery method.

  It can be used as a method for recovering lithium from a lithium ion secondary battery and a method for recovering metal.

Sectional drawing which shows the lithium ion secondary battery used as the object of the lithium collection | recovery method which concerns on embodiment of this invention. The flowchart which shows the outline of the lithium collection | recovery method and metal collection | recovery method which concern on embodiment of this invention. The figure which shows the outline of the refinement | purification process and collection | recovery process which concern on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lithium ion secondary battery 11 Positive electrode 12 Negative electrode 13 Solid electrolyte

Claims (5)

A lithium ion secondary battery comprising a positive electrode, a negative electrode, and a solid electrolyte containing lithium (Li) interposed between the positive electrode and the negative electrode is decomposed into the positive electrode, the negative electrode, the solid electrolyte, and other members Disassembling process,
A dissolution step of dissolving lithium contained in the solid electrolyte taken out in the decomposition step;
A separation step of separating the lithium-dissolved solution in which the lithium is dissolved and the residue in the dissolution step;
A method of recovering lithium, comprising: The solid electrolyte is a sulfide-based fired body heat-treated using lithium sulfide and phosphorus sulfide as raw materials,
2. The method for recovering lithium according to claim 1, wherein in the dissolving step, the positive electrode, the negative electrode, and the electrolyte are washed with water to dissolve the lithium in water. After the separation step, adjusting the pH of the lithium solution to precipitate impurity metals other than lithium, purifying the precipitate to obtain a high-purity lithium solution by separating the precipitate;
A recovery step of adding a water-soluble carbonate to the high-purity lithium solution and recovering the generated lithium carbonate;
The lithium recovery method according to claim 1, wherein the lithium recovery method comprises: After carrying out the lithium recovery method according to any one of claims 1 to 3,
A metal recovery method comprising: treating at least one of the positive electrode, the negative electrode, and the residue as a material to be treated, and recovering a metal contained in the lithium ion secondary battery. An elution step of eluting the metal contained in the material to be treated by acid treatment;
A metal recovery step of treating the metal solution obtained in the elution step and recovering the generated precipitate;
The metal recovery method according to claim 4, comprising:

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