JP2022182229A - Metal recovery method from lithium ion battery - Google Patents

Abstract

To make it possible to extract cobalt and nickel after sufficiently selecting and removing manganese (Mn) and iron (Fe) that are unnecessary components in a leaching step for leaching target metals, when recovering valuable metals from a battery slag of lithium ion batteries containing valuable metals.SOLUTION: A method for recovering a valuable metal from battery slag of lithium ion batteries containing valuable metals according to the present invention includes (a) a step of dispersing the battery slag of a lithium ion batteries in sulfuric acid to obtain a slurry having the hydrogen ion index (pH) of 1 or less. (b) a step of adding an oxidizing agent to the slurry to set the oxidation-reduction potential (ORP) to 1200 to 1350 mV (vs. Ag/AgCl); and (c) a step of separating manganese and other valuable metals from the slurry after addition of the oxidizing agent.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method for recovering metals from lithium ion batteries, and more specifically to a method for recovering valuable metals from battery slag of lithium ion batteries containing valuable metals.

Lithium ion batteries are used in many industrial fields, including various electronic devices, and generally known are those that use a lithium metal composite oxide containing manganese, nickel and cobalt as a positive electrode material. In recent years, with the increase in the amount used and the expansion of the range of use, the amount of batteries discarded due to product life and defects in the manufacturing process is increasing. Under such circumstances, it is desirable to recover expensive elements such as nickel and cobalt from large amounts of discarded lithium-ion battery slag for reuse at relatively low cost and easily.

In order to process battery slag of lithium ion batteries to recover valuable metals, for example, as a conventional general method, first, if necessary, it is obtained through each process such as roasting, crushing and sieving. A battery slag of a powdery or granular lithium ion battery is prepared. The battery slag is acid-leached, and lithium, nickel, cobalt, manganese, iron, copper, aluminum, etc. that may be contained therein are dissolved in the solution to obtain a leachate. A solvent extraction method is performed on the leachate to sequentially separate each metal element. In doing so, each valuable metal can be recovered by first recovering iron and aluminum, followed by manganese and copper, then cobalt, then nickel, and finally leaving lithium in the aqueous phase.

Patent Document 1 describes a method for recovering metals from recycled lithium-ion battery raw materials, in which powdery or granular recycled raw materials for lithium-ion batteries are brought into contact with an acid, and hydrogen peroxide solution is added to leach out the target metal. In the process, the hydrogen ion exponent (hereinafter simply referred to as "pH") of the acidic solution is set to 0<pH<4, and the oxidation-reduction potential (hereinafter simply referred to as "ORP") is set at 600 to 1400 mV vs. It discloses incorporating oxides of manganese into the residue as Ag/AgCl. Moreover, Patent Document 1 discloses that it is preferable to add a compound containing manganese to the acidic solution from the viewpoint of further promoting the leaching of the target metal.

Patent Document 2 discloses a method for recovering metals from recycled lithium-ion battery raw materials, in which powdery or granular recycled lithium-ion battery raw materials are added to an acidic solution such as sulfuric acid and leached in a leaching step to further promote leaching. A manganese compound was added for the purpose, the pH of the acidic solution was adjusted to 0<pH<4, and the ORP was adjusted to 600-1400mVvs. It discloses incorporating oxides of manganese into the residue as Ag/AgCl.

Patent Document 3 describes a method for recovering copper, nickel, and cobalt from waste lithium-ion batteries, in which an alloy obtained by melting waste lithium-ion batteries is dissolved in an acidic solution, and an oxidizing agent and a neutralizing agent are added to the leachate. is added to maintain the ORP of the leachate in the range of 800-1300 mV and the pH in the range of 1-3. Disclosed is the removal of precipitates.

Patent Document 4 discloses a method for leaching manganese from a lithium ion secondary battery, in which manganese is leached into a solution without incorporating oxides of manganese into the residue in the leaching process as in Patent Documents 1 to 3. By setting the pH of the solution at the time to 4.00 or less and the ORP (3.3M KCl-Ag/AgCl) to −350 mV or less, manganese is selectively leached into the solution compared to cobalt and nickel. Disclose.

JP 2016-186118 JP 2016-186113 JP 2021-70843 JP 2021-55159

Patent Documents 1 to 4 all control the hydrogen ion exponent (pH) and oxidation-reduction potential (ORP) in the leaching process to separate and remove manganese, but the manganese separation efficiency for cobalt and nickel is low. It is not necessarily expensive, nor does it focus on separating and removing other unwanted components such as iron, and the removal of unwanted components prior to the extraction process for cobalt and nickel is not always sufficient.

The present invention has been made in view of the above-described circumstances of the prior art, and its object is to sufficiently reduce manganese and iron, which are unnecessary components, to cobalt and nickel in the leaching step of acid leaching the target metal. It is an object of the present invention to provide a method for recovering valuable metals from battery slag of a lithium-ion battery containing valuable metals, which can be separated and removed before subsequent extraction of cobalt and nickel.

The present invention provides a method for recovering valuable metals from battery slag of lithium ion batteries containing valuable metals. In one aspect of the method, (a) dispersing battery slag of a lithium ion battery in sulfuric acid to obtain a slurry having a hydrogen ion index (pH) of 1 or less, and (b) adding an oxidizing agent to the slurry. and (c) separating manganese and other valuable metals from the slurry after addition of the oxidizing agent. include.

In another aspect of the present invention, after the step of (b) adding an oxidizing agent to the slurry, (d) adding an alkali to the slurry to make the hydrogen ion exponent (pH) in the range of 3 to 4 and oxidizing A step of adjusting the reduction potential (ORP) in the range of 500 to 700 mV (vs. Ag/AgCl), and (e) separating manganese and iron and other valuable metals from the adjusted slurry. include.

Another aspect of the present invention further comprises the step of (f) adding a reducing agent to the slurry after the step of (a) obtaining the slurry.

According to the present invention, in the leaching step of acid-leaching the target metal, manganese and iron, which are unnecessary components, are sufficiently separated and removed from cobalt and nickel (with high efficiency), and then cobalt and nickel are extracted/removed. It is possible to collect.

FIG. 2 is a diagram showing steps of a method for recovering valuable metals from battery slag of a lithium ion battery according to one embodiment of the present invention.

Embodiments of the present invention will be described with reference to drawings and tables. FIG. 1 is a diagram showing steps of a method for recovering valuable metals from battery slag of a lithium ion battery according to one embodiment of the present invention. First, an overview (flow) of the method of the present invention will be described with reference to FIG.

In step S1, as a leaching step (slurry generating step) for leaching the target metal with acid, the battery slag of the lithium ion battery is dispersed in sulfuric acid to obtain a slurry. Examples of battery residue include positive electrode active material, black sand (BS), and the like. Details of the battery residue will be described later. A reducing agent is added to the slurry if necessary depending on the type of battery slag. For example, when the battery slag is a positive electrode active material, it is necessary to add a reducing agent, but when it is black sand (BS), it is not always necessary to add a reducing agent. As the reducing agent, for example, at least one selected from hydrogen peroxide, sulfites, sulfurous acid gas, iron (II) salts, oxalic acid, iron, copper, aluminum, carbon, and alloys containing iron, copper, and aluminum. The above can be used.

In adjusting the pH in step S2, sulfuric acid is further added so that the pH of the slurry becomes 1 or less. Steps S1 and S2 may be performed individually as separate steps, or may be performed integrally as one step. That is, in the former case, for example, after the battery slag is dispersed in a sulfuric acid solution having a predetermined concentration, the amount (concentration) of sulfuric acid is gradually adjusted so that the pH becomes 1 or less. In the latter case, as one of the leaching steps, for example, the battery slag is dispersed in a sulfuric acid solution while gradually adjusting the amount (concentration) of sulfuric acid so that the pH becomes 1 or less from the beginning.

In step S3, an oxidizing agent is added to the slurry. At that time, the addition amount of the oxidizing agent is adjusted so that the ORP is 1200 to 1350 mV (vs. Ag/AgCl). As a result, manganese is precipitated as manganese oxide, and cobalt, nickel, etc. to be extracted (recovered) later are not precipitated but are leached as ions into the solution after leaching. This allows manganese to be separated from other valuable metals such as cobalt and nickel. As the oxidizing agent, for example, at least one selected from manganese compounds, potassium permanganate, manganese dioxide, sodium hypochlorite, hypochlorous acid, air, oxygen, ozone, sodium nitrite and chlorine gas. The above can be used. Furthermore, the manganese compound includes recovering and using the manganese oxide obtained in step S3.

In step S4, an alkali is added to the slurry. At that time, the pH is adjusted to the range of 3 to 4, and the ORP is adjusted to the range of 500 to 700 mV (vs. Ag/AgCl) by adding an alkali. As a result, a large amount of iron is precipitated in addition to manganese, and cobalt, nickel, etc. remain as ions in the leaching solution without being precipitated. This allows iron and manganese to be separated from other valuable metals such as cobalt and nickel. Examples of alkalis that can be used include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water, sodium carbonate, sodium hydrogen carbonate, and other commonly used alkaline substances.

In step S5, a solution containing cobalt, nickel, lithium, aluminum, copper, etc. is obtained as a post-leaching solution after separation of iron and manganese. It should be noted that it is difficult to completely separate iron and manganese by 100%, and a small amount of iron and manganese may remain in the solution. In that case, the next step S6 may be performed.

In step S6, solvent extraction (I) is first performed to separate aluminum and copper, as well as residual iron and manganese, from the solution. Next, solvent extraction (II) is performed to separate and recover the valuable metals cobalt and nickel from the residual solution. As the solvent extractant, for example, a phosphonate extractant, a phosphate ester extractant, an oxime extractant, or the like can be used.

Next, characteristic items in each step of the method of the present invention described above will be described.
[Battery waste]
The battery slag used in the method for recovering valuable metals of the present embodiment is not particularly limited, and lithium ion batteries discarded due to the life of the battery product, manufacturing defects, or other reasons are crushed, magnetically sorted, particle size sorted, specific gravity sorted, Any one can be used as long as it can be obtained by eddy current screening or the like. At that time, part of iron, aluminum, and copper may be removed first. In addition, the battery slag as a raw material includes a positive electrode material for a lithium ion battery and a positive electrode active material, and a mixture of two or more of these may be used.

Examples of battery slag include those (black sand (BS)) obtained by removing exterior plastics from lithium ion batteries and then subjecting them to roasting, chemical treatment, crushing and sorting. Also, if the equipment is well equipped, lithium ion batteries obtained by roasting, chemical treatment, crushing and sorting without removing the exterior plastic may be used. Among them, it is preferable to use the battery residue that has undergone the roasting process.

From the viewpoint of reducing the content of organic substances contained in the electrolyte, separator, binder, etc., the roasting temperature in the roasting step is preferably 150° C. or higher, more preferably 400° C. or higher. The upper limit of the roasting temperature is not particularly limited, but if the positive electrode material contains aluminum, the melting of the aluminum may adversely affect the subsequent steps, so the roasting temperature is preferably 660 ° C. or less. preferable.

Valuable metals contained in the battery slag of lithium ion batteries are not particularly limited, but include lithium, cobalt, nickel, manganese, copper, aluminum, iron, etc. Lithium, one or more of cobalt and nickel, Manganese and are preferably included as valuable metals to be recovered.

[Leaching (slurry generation)]
In the leaching step of dispersing the battery slag of a lithium ion battery in sulfuric acid to obtain a slurry (this step is also referred to as a "slurry production step"), even if sulfuric acid is added to the battery slag, the battery slag is added to the sulfuric acid. good too. In the slurry production step, after adding the battery residue to the sulfuric acid, or after adding the battery residue to the sulfuric acid, the mixture is stirred for 0 to 3 hours while maintaining the liquid temperature at 30 to 80° C., for example.

The concentration of sulfuric acid used in the slurry generation step is not particularly limited, but from the viewpoint of leaching valuable metals more efficiently, it is preferably 3.5 to 14.5 mol / L, and the heat of dilution From the viewpoint of raising the temperature at , it is more preferable to add sulfuric acid after dispersing the battery residue in water to adjust the concentration to 3.5 to 14.5 mol/L.

The pH of the slurry is preferably 1.0 or less, more preferably 0.0 to 1.0. When the pH of the slurry is 0.0 or more, the raw material cost tends to be suppressed, and when it is 1.0 or less, the valuable metals and manganese contained in the battery slag are sufficiently separated in the leaching after the slurry is produced. tend to be able to

[ORP adjustment (addition of oxidizing agent)]
An oxidizing agent is added to a slurry having a pH of 1.0 or less. At that time, the addition amount of the oxidizing agent is adjusted so that the ORP is 1200 to 1350 mV (vs. Ag/AgCl). The oxidizing agent is, for example, potassium permanganate, as described above. By adjusting the ORP by adding this oxidizing agent, the reaction in which the manganese ions dissolved in the slurry are precipitated as oxides is promoted, so manganese tends to be more efficiently separated from other valuable metals.

When potassium permanganate is added as an oxidizing agent, the amount to be added is not particularly limited. KMnO ₄ /(Co+Ni)) is preferably about 0.20 to 0.50. It is preferable that the reaction time after addition of potassium permanganate is, for example, about 1 to 3 hours, and the reaction temperature is, for example, about 30 to 80.degree.

[pH adjustment (alkaline addition)]
Alkali is added to the slurry after addition of the oxidizing agent. At that time, the pH is adjusted to the range of 3 to 4 and the ORP is adjusted to the range of 500 to 700 mV (Ag+/AgCl) by adding an alkali. The alkali is, for example, sodium hydroxide, as described above. By adjusting the pH and ORP by adding alkali, the reaction in which iron ions dissolved in the slurry are precipitated as hydroxides is promoted, so there is a tendency to separate iron in addition to manganese from other valuable metals more efficiently. be. When sodium hydroxide is added as an alkali, for example, the reaction time after addition of a 25 wt % sodium hydroxide aqueous solution is preferably about 0.5 hours, and the reaction temperature is preferably about 50°C.

[Separation of valuable metals (separation of manganese and iron)]
As a method for separating manganese and iron and other valuable metals from the slurry after step S3 (addition of oxidizing agent) and step S4 (addition of alkali) in FIG. Although not particularly limited, for example, a method in which manganese oxides and iron hydroxide precipitated in the slurry are recovered as a leach residue by sequential filtration or the like, and valuable metals other than manganese and iron are recovered as a leachate, or centrifugation or decantation. etc. are also mentioned. Thereby, manganese and iron can be separated from other valuable metals.

In the method for recovering valuable metals of the present embodiment, the leaching rate of valuable metals other than manganese is preferably 90% by mass or more, and more preferably 95% by mass or more. Also, the leaching rate of manganese and iron is preferably 5% by mass or less, more preferably 1% by mass or less.

このリチウムイオン電池滓（ＢＳ）１０ｇを、９８ｗｔ％（１８．４ｍｏｌ／Ｌ）の濃硫酸３６．７ｇと水８０．１ｇを加えた３．７ｍｏｌ／Ｌ硫酸溶液に分散させ、８０℃に昇温後、２ｈ攪拌を行い、可溶分を溶出させて、リチウムイオン電池滓硫酸浸出液を得た。以下の、実施例および比較例に示す金属回収率は、上記可溶分量を１００として算出した。なお、ＢＳの組成はその製造方法の特性上、リチウムイオン電池滓硫酸浸出液のｐＨは一定しない。 Table 1 shows the main composition of black sand (BS), which is a lithium ion battery slag used for the examination of the examples and comparative examples shown below.

Table 1 Composition (wt%) of lithium-ion battery residue (BS)

10 g of this lithium ion battery residue (BS) was dispersed in a 3.7 mol/L sulfuric acid solution containing 36.7 g of 98 wt% (18.4 mol/L) concentrated sulfuric acid and 80.1 g of water, and the temperature was raised to 80°C. After that, the mixture was stirred for 2 hours to elute the soluble matter to obtain a lithium ion battery slag sulfuric acid leaching solution. The metal recovery rates shown in the following examples and comparative examples were calculated with the soluble content as 100. Incidentally, the pH of the lithium ion battery slag sulfuric acid leaching solution is not constant due to the characteristics of the production method of BS.

(Example 1)
21 mL of 9.2 mol/L sulfuric acid was added to 100 mL of the lithium ion battery slag sulfuric acid leaching solution of pH 1.68 to adjust the pH to 0.21. To this lithium ion battery slag sulfuric acid leaching solution, potassium permanganate was added in an amount of 0.42 (0 .013 mol) was added. After the temperature was raised to 50°C, the temperature was maintained at 50°C for 2 hours. The ORP at this time was 1291 mV (vs. Ag/AgCl).

Thereafter, the lithium ion battery slag sulfuric acid leaching solution was filtered, and the leached components were quantitatively analyzed by ICP. The recovery rate (wt%) of cobalt, nickel and manganese is
Co: 94.9
Ni: 98.9
Mn: 1.0
, and it was confirmed that manganese could be separated from cobalt and nickel with high efficiency.

(Example 2-7)
While maintaining the pH below 1 (pH=0.65 to 0.98) by the same basic operation as in Example 1, the experiment was carried out by changing the reaction conditions as follows. The ORP after KMnO4 addition was 1239-1316 mV (vs. Ag/AgCl).
Examples 2 and 3 KMnO4 addition amount (KMnO4/(Co+Ni)):
0.31, 0.45
Examples 4 and 5 Reaction temperature: 30, 80°C
Examples 6 and 7 Reaction time: 1 and 3 hours As a result, the recovery rates (wt%) of cobalt, nickel and manganese were
Co: 89.2-97.5
Ni: 98.8-99.5
Mn: 0.95-7.58
It was confirmed that manganese can be separated from cobalt and nickel with high efficiency.

(Examples 8-18)
After Example 1, a 25 wt % sodium hydroxide aqueous solution was added to raise the pH to around 3.0 to 4.0, and at the same time adjust the ORP to a range of 500 to 700 mV (vs. Ag/AgCl).
KMnO4 addition amount (KMnO4/(Co+Ni)): 0.22 to 0.32
pH: 2.91-3.58
ORP: 532-653mV (vs.Ag/AgCl)
As a result, the recovery rate (wt%) of cobalt, nickel, manganese and iron is
Co: 84.9-98.1
Ni: 96.7-99.3
Mn: 0.12-13.85
Fe: 0
It was confirmed that manganese and iron can be separated from cobalt and nickel with high efficiency.

(Comparative example 1)
The same operation as in Example 1 was performed, except that 0.013 mol of potassium permanganate was added without adjusting the pH to 1 or less (with the pH remaining at 1.68). After the temperature was raised to 50°C, the temperature was maintained at 50°C for 2 hours. The ORP at this time was 1168 mV (vs. Ag/AgCl).

Thereafter, the lithium ion battery slag sulfuric acid leaching solution was filtered, and the leached components were quantitatively analyzed by ICP. The recovery rate (wt%) of cobalt, nickel and manganese is
Co: 80.2
Ni: 97.9
Mn: 0.5
, the recovery rate of cobalt was about 16% lower than that of Example 1, and the separation efficiency of manganese from cobalt was also lowered. From this, it was confirmed that adjusting the pH of Example 1 to 1 or less is effective.

(Comparative Example 2-4)
As in Comparative Example 1, without adjusting the pH to 1 or less, a 25 wt% sodium hydroxide aqueous solution was added to raise the pH to 2.22, 3.41, and 4.08, and then permanganic acid was added. The same operation as in Example 1 was performed with the addition of potassium. The ORP at this time was 711 to 1117 mV (vs. Ag/AgCl).

As a result, the recovery rate (wt%) of cobalt, nickel, manganese and iron is
Co: 74.5-82.4
Ni: 98.2-98.9
Mn: 0.95-2.37
Fe: 19.1-31.6
, the recovery of cobalt was about 14-22% lower than that of Example 1, and the separation efficiency of manganese and iron from cobalt and nickel was also lowered. From this, it was confirmed that adjusting the pH of Examples 2-7 to 1 or less is effective.

Embodiments of the present invention have been described with reference to figures and tables. However, the invention is not limited to these embodiments. The present invention can be implemented with various improvements, modifications, and variations based on the knowledge of those skilled in the art without departing from the spirit of the invention.

A method for recovering valuable metals from battery residue of lithium ion batteries containing valuable metals can be widely used in recovering valuable metals from waste lithium ion batteries.

The present invention provides a method for recovering valuable metals from battery slag of lithium ion batteries containing valuable metals. In one aspect of the method, (a) dispersing battery slag of a lithium ion battery in sulfuric acid to obtain a slurry having a hydrogen ion index (pH) of less than 1; and (b) adding an oxidizing agent to the slurry. and (c) separating manganese and other valuable metals from the slurry after addition of the oxidizing agent. include.

In step S3, an oxidizing agent is added to the slurry. At that time, the addition amount of the oxidizing agent is adjusted so that the ORP is 1200 to 1350 mV (vs. Ag/AgCl). As a result, manganese is precipitated as manganese oxide, and cobalt, nickel, etc. to be extracted (recovered) later are not precipitated but are leached as ions into the solution after leaching. This allows manganese to be separated from other valuable metals such as cobalt and nickel. As the oxidizing agent, for example, at least one selected from manganese compounds, potassium permanganate, manganese dioxide, sodium hypochlorite, hypochlorous acid, air, oxygen, ozone , and chlorine gas is used. be able to. Furthermore, the manganese compound includes recovering and using the manganese oxide obtained in step S3.

Claims (6)

A method for recovering valuable metals from battery slag of a lithium-ion battery containing valuable metals, comprising:
a step of dispersing the battery slag of the lithium ion battery in sulfuric acid to obtain a slurry having a hydrogen ion exponent (pH) of 1 or less;
A step of adding an oxidizing agent to the slurry to set the oxidation-reduction potential (ORP) to 1200 to 1350 mV (vs. Ag/AgCl);
separating manganese and other valuable metals from the slurry after addition of the oxidizing agent;
A method of recovering valuable metals from battery slag comprising: After the step of adding an oxidizing agent to the slurry, alkali is added to the slurry to make the hydrogen ion exponent (pH) in the range of 3 to 4 and the oxidation reduction potential (ORP) to 500 to 700 mV (vs. Ag /AgCl) range;
A step of separating manganese and iron and other valuable metals from the adjusted slurry;
2. The method of claim 1, further comprising: 3. The method of claim 1 or 2, further comprising adding a reducing agent to the slurry after obtaining the slurry. 3. The method according to claim 2, wherein the alkali includes at least one selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, aqueous ammonia, sodium carbonate, and sodium hydrogen carbonate. The method according to claim 3, wherein the reducing agent is at least one selected from hydrogen peroxide, sulfites, sulfurous acid gas, iron, copper, aluminum, and alloys containing iron, copper, and aluminum. . The oxidizing agent is selected from manganese compounds, potassium permanganate, manganese dioxide, sodium hypochlorite, hypochlorous acid, air, oxygen, ozone, sodium nitrite, recovered manganese oxide and chlorine gas. The method according to any one of claims 1 to 5, wherein at least one kind is used.

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