JP2022118594A - Recovery method and recovery apparatus for valuable metal - Google Patents

Abstract

To recover Ni or/and Co contained in battery slag by efficiently leaching it into sulfuric acid.SOLUTION: A recovery method includes a heating step S3 for heating battery slag M1 having a cathode active material containing Ni or/and Co and an anode active material containing graphite to oxidize the graphite contained in the anode active material in the battery slag M1 and thus to generate carbon dioxide G, an acid leaching step S4 for adding sulfuric acid to residual powder M2 remaining after generating carbon dioxide G from the battery slag M1 to leach Ni or/and Co contained in the cathode active material in the residual powder M2 into the sulfuric acid and thus to produce a leachate E1, and recovery steps S5-S15 for recovering the Ni or/and Co contained in the leachate E1.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a recovery method and recovery apparatus for valuable metals.

Patent Literature 1 listed below describes a technique of adding sulfuric acid to battery slag collected from battery waste, thereby leaching and recovering valuable metals contained in the battery slag with sulfuric acid.

However, research by the present inventors has revealed that Ni and Co, among the valuable metals contained in the battery slag, cannot be efficiently leached into sulfuric acid in the technique described in Patent Document 1 below.

JP 2019-160429 A

An object of the present invention is to efficiently leach Ni and/or Co contained in battery slag into sulfuric acid for recovery.

A method for recovering valuable metals according to the first item of the present invention is characterized by heating a battery slag having a positive electrode active material containing Ni or/and Co and a negative electrode active material containing graphite, whereby the negative electrode in the battery slag is A heating step of oxidizing the graphite contained in the active material to generate carbon dioxide gas, and adding sulfuric acid to the residual powder remaining after the carbon dioxide gas is generated from the battery residue, the positive electrode active material in the residual powder. It has an acid leaching step of leaching Ni or/and Co contained in the substance into the sulfuric acid to produce a leachate, and a recovery step of recovering the Ni and/or Co contained in the leachate.

According to the first item, Ni or/and Co contained in the positive electrode active material in the battery slag is brought into contact with graphite contained in the negative electrode active material in the heating step, and electrons contained in the graphite are transferred to Ni or/and Co. It can be moved to produce carbon dioxide. Therefore, Ni and/or Co contained in the positive electrode active material in the battery slag can be reduced to divalent and efficiently exuded into sulfuric acid.

Moreover, according to the first item, the residual powder can be obtained by reducing the volume of the battery residue. Then, since sulfuric acid is added to the volume-reduced battery slag (residual powder), Ni and Co contained in the positive electrode active material in the residual powder can be leached into the sulfuric acid simply by adding a small amount of sulfuric acid. can be done.

In the method for recovering valuable metals according to the second item of the present invention, hydrogen peroxide is added to the residual powder together with the sulfuric acid in the acid leaching step.

According to the second item, Ni and Co, which were not reduced to divalents during the generation of carbon dioxide in the heating step, can be reduced to divalents with hydrogen peroxide in the acid leaching step and efficiently leached into sulfuric acid.

The recovery step of the method for recovering valuable metals according to the third item of the present invention includes an addition step of adding a sulfiding agent to the leachate to generate a treatment liquid, and filtering the treatment liquid to remove the treatment liquid. and a filtering step of separating into a filtrate and a residue containing Ni and/or Co contained in the leachate.

According to the third item, Ni and Co contained in the leachate can be efficiently recovered as residues in the filtration process.

A method for recovering valuable metals according to the fourth item of the present invention comprises a crushing step of crushing battery waste to produce crushed products, and a taking-out step of removing aluminum pieces from the crushed products and taking out the battery slag. have more. In the heating step, the removed battery slag is heated.

According to the fourth item, by removing the aluminum pieces from the crushed material and heating the battery slag taken out in the heating step, efficient reduction of Ni and Co by melting the aluminum pieces in the heating step is inhibited. can be prevented. Therefore, Ni and Co contained in the residual powder can be efficiently leached into sulfuric acid in the acid leaching step. Also, the aluminum pieces removed in the extraction process can be recovered and effectively used.

In the method for recovering valuable metals according to the fifth item of the present invention, the battery slag is heated to 700° C. or higher in the heating step.

According to the fifth item, in the heating step, Ni and/or Co contained in the positive electrode active material in the battery slag can be efficiently reduced to divalent. Therefore, in the acid leaching step, Ni and Co contained in the residual powder can be efficiently leached into sulfuric acid.

In the method for recovering valuable metals according to the sixth item of the present invention, in the acid leaching step, after adding 2 mol/l or more of sulfuric acid to the residual powder, the leachate is heated to 60° C. or more for 4 hours. The above is agitated.

According to the sixth item, Ni and Co contained in the residual powder can be efficiently leached into sulfuric acid in the acid leaching step.

The apparatus for recovering valuable metals according to the seventh item of the present invention heats a battery slag having a positive electrode active material containing Ni or/and Co and a negative electrode active material containing graphite, whereby the negative electrode in the battery slag A heating device for oxidizing graphite contained in an active material to generate carbon dioxide gas, and adding sulfuric acid to the residual powder remaining after the carbon dioxide gas is generated from the battery slag, thereby heating the positive electrode active material in the residual powder. An acid leaching device for leaching Ni or/and Co contained in a substance into the sulfuric acid to generate a leaching solution, and a recovery device for recovering the Ni and/or Co contained in the leaching solution.

According to the seventh item, the same effect as the first item can be produced.

As described above, according to the present invention, Ni and/or Co contained in battery residue can be efficiently leached into sulfuric acid and recovered.

FIG. 1 is an explanatory diagram for explaining the procedure of a valuable metal recovery method according to an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining a recovering apparatus for valuable metals according to one embodiment of the present invention.

A method for recovering valuable metals according to one embodiment of the present invention will be described. This recovery method is applied to the disposal of so-called lithium ion battery waste. FIG. 1 shows the procedure of a valuable metal recovery method according to one embodiment of the present invention. FIG. 2 schematically shows a valuable metal recovery apparatus 100 for carrying out the recovery method shown in FIG.

As shown in FIG. 1, this recovery method includes a crushing step S1, a removal step S2, a heating step S3, a first acid leaching step S4, a first addition step S5, a first filtration step S6, a neutralization step S7, and a second Filtration step S8, second addition step S9, third filtration step S10, washing step S11, fourth filtration step S12, second acid leaching step S13, fifth filtration step S14, solvent extraction step S15, and carbonation step S16. have. Steps S5 to S15 correspond to recovery steps of Ni and Co using a recovery apparatus for Ni and Co.

The crushing step S1 is a step of crushing the battery waste W1 by the crushing device 1 (FIG. 2) to produce the crushed material C. As shown in FIG. For the crushing device 1, for example, a twin-screw crusher and a hammer crusher can be used. The battery waste W1 contains metals such as Li, Ni, Co, Mn, Al and Cu. Therefore, the crushed material C also contains these metals.

The removal step S2 is a step of removing the impurities I from the crushed material C by the removal device 2 (FIG. 2) and removing the battery slag M1. A sieve such as a vibrating sieve can be used for the take-out device 2 . When a sieve is used, the sieving fraction is the battery slag M1 and the sieve residue is the impurity I. The battery residue M1 is a mixed powder containing the positive electrode active material and the negative electrode active material contained in the battery waste W1. The impurity I contains aluminum pieces contained in the battery waste W1.

The heating step S3 is a step of heating the battery residue M1 with the heating device 3 (FIG. 2) to oxidize the graphite contained in the negative electrode active material in the battery residue M1 and generate the carbon dioxide gas G. Electrons contained in graphite move to metal ions (for example, trivalent or tetravalent Ni ions and Co ions) contained in the positive electrode active material in the battery residue M1 as the carbon dioxide gas G is produced in the heating step S3. As a result, these metal ions are reduced to divalent ions. In the heating step S3, the carbon dioxide gas G is released from the battery slag M1 to produce residual powder M2.

Regarding the temperature for heating the battery residue M1 in the heating step S3, the valuable metal contained in the battery residue M1 (particularly, in the prior art, trivalent or tetravalent Ni, which is difficult to leach out with sulfuric acid in the first acid leaching step S4, ions and Co ions) to be divalent efficiently, the temperature is preferably 700° C. or higher, more preferably 800° C. or higher and 900° C. or lower. The interior of this heating device is preferably an atmospheric atmosphere, but is not limited to this, and may be an atmosphere capable of providing oxygen for oxidizing graphite.

In the first acid leaching step S4, sulfuric acid and hydrogen peroxide A1 are added to the residual powder M2 in the first acid leaching device 4 (FIG. 2) to Ni ions and Co ions contained in the positive electrode active material) are leached into sulfuric acid. In the first acid leaching step S4, a leaching solution E1 is produced which is a mixed solution of the residual powder M2, sulfuric acid and hydrogen peroxide A1. Regarding the conditions for leaching the metals contained in the residual powder M2 into sulfuric acid, in order to efficiently leach the metal ions (especially Ni ions and Co ions) contained in the residual powder M2 into sulfuric acid, It is preferable to stir the leachate E1 at 60° C. or higher for 4 hours or longer after adding 2 mol/l or more of sulfuric acid.

The first addition step S5 is a step of adding a sulfiding agent A2 to the leachate E1 in the first addition device 5 (FIG. 2) to generate a sulfide of Cu contained in the leachate E1. In the first addition step S5, a treatment liquid P1, which is a mixed liquid of the leachate E1 and the sulfiding agent A2, is produced. Here, in the first addition step S5, in order to efficiently generate Cu sulfide contained in the leachate E1, the pH of the treatment liquid P1 is less than 1 and the ORP (oxidation-reduction potential) is less than 0 mV (vs. Sulphidating agent A2 is added to Ag/AgCl). A sulfur content such as sodium hydrogen sulfide can be used as the sulfiding agent A2.

The first filtering step S6 is a step of filtering the treatment liquid P1 into a filtrate F1 and a residue R1 in the first filtering device 6 (FIG. 2). The filtrate F1 contains Li, Ni, Co, Mn and Al. Residue R1 contains Cu sulfide.

The neutralization step S7 is a step of adding a neutralizing agent A3 to the filtrate F1 in the neutralization device 7 (FIG. 2) to generate hydroxides of Mn and Al contained in the filtrate F1. In the neutralization step S7, a neutralized liquid N is produced which is a mixed liquid of the filtrate F1 and the neutralizing agent A3. Here, in the neutralization step S7, in order to efficiently generate hydroxides of Mn and Al contained in the filtrate F1, the pH of the neutralization liquid N is adjusted to 3.0 or more and 4.0 or less. Add Admixture A3. For example, an aqueous sodium hydroxide solution can be used as the neutralizing agent A3.

The second filtering step S8 is a step of filtering the neutralized liquid N into a filtrate F2 and a residue R2 in the second filtering device 8 (FIG. 2). The filtrate F2 contains Li, Ni and Co. The residue R2 contains hydroxides of Mn and Al.

The second addition step S9 is a step of adding a sulfiding agent A4 to the filtrate F2 in the second addition device 9 (FIG. 2) to generate sulfides of Ni and Co contained in the filtrate F2. In the second addition step S9, a treated liquid P2 is produced which is a mixed liquid of the filtrate F2 and the sulfiding agent A4. Here, in the second addition step S9, in order to efficiently generate the sulfides of Ni and Co contained in the filtrate F2, the pH of the treatment liquid P2 is 2.0 or more and 3.0 or less and ORP (oxidation A sulfiding agent A4 is added so that the reduction potential) is less than -400 mV (vs Ag/AgCl). A sulfur content such as sodium hydrogen sulfide can be used as the sulfiding agent A4.

The third filtering step S10 is a step of filtering the treatment liquid P2 into a filtrate F3 and a residue R3 in the third filtering device 10 (FIG. 2). The filtrate F3 contains Li. Residue R3 contains sulfides of Ni and Co.

The cleaning step S11 is a step in which the residue R3 is washed with the cleaning water W2 in the cleaning device 11 (FIG. 2) so that the Li remaining in the residue R3 is exuded into the cleaning water W2. In the cleaning step S11, a slurry S is produced which is a mixture of the residue R3 and the cleaning water W2.

The fourth filtering step S12 is a step of filtering the slurry S into a filtrate F4 and a residue R4 in the fourth filtering device 12 (FIG. 2). The filtrate F4 contains Li remaining in the residue R3 without transferring to the filtrate F3. Residue R4 contains sulfides of Ni and Co.

In the second acid leaching step S13, "sulfuric acid, hydrogen peroxide and sodium hypochlorite A5" (the entirety of which is denoted by A5) is added to the residue R4 in the second acid leaching device 13 (Fig. 2). This is a step of leaching Ni and Co contained in the residue R4 into sulfuric acid. In the second acid leaching step S13, a leaching solution E2 is produced which is a mixed solution of the residue R4, sulfuric acid, hydrogen peroxide and sodium hypochlorite A5. Here, it is conceivable that the residue R4 contains a trace amount of Mn, but this Mn exists as manganese dioxide in the leachate E2 due to the addition of sulfuric acid, hydrogen peroxide and sodium hypochlorite A5. Further, in the leachate E2, the sulfides of Ni and Co contained in the residue R4 react with sulfuric acid and hydrogen peroxide to produce sulfur (elementary substance).

The fifth filtering step S14 is a step of filtering the exudate E2 into a filtrate F5 and a residue R5 in the fifth filtering device 14 (FIG. 2). Filtrate F5 contains Ni and Co. Residue R5 contains manganese dioxide and sulfur (elementary).

The solvent extraction step S15 is a step of adding an organic solvent (extraction solvent) and sulfuric acid (reverse extraction solvent) to the filtrate F5 in the solvent extraction device 15 (FIG. 2) such as a mixer-settler. As a result, Ni and Co contained in the filtrate F5 are recovered as sulfate V1, and impurities (phosphorus and fluorine) contained in the filtrate F5 are discharged as a solution L.

The carbonation step S16 is a step of adding a carbonate A6 to the filtrate F3 of the third filtration step S10 and the filtrate F4 of the fourth filtration step S12 in the carbonation device 16 (FIG. 2) to generate lithium carbonate V2. . For this carbonate, for example, sodium carbonate or sodium carbonate hydrate can be used. Furthermore, if necessary, in the carbonation step S16, the mixture of the filtrate F3, the filtrate F4 and the carbonate A6 may be filtered to separate the filtrate and the residue. Lithium carbonate V2 can be recovered as this residue.

According to the above embodiment, in the heating step S3, the Ni and/or Co contained in the positive electrode active material and the graphite contained in the negative electrode active material in the battery residue M1 are in contact with each other in a powder state, and the carbon dioxide gas G is generated. During the production process, electrons contained in graphite move to Ni or/and Co. Therefore, Ni and/or Co contained in the positive electrode active material in the battery residue M1 can be reduced to divalent. Therefore, these Ni and/or Co can be efficiently leached into sulfuric acid in the first acid leaching step S4.

Further, according to the above embodiment, in the first acid leaching step S4, sulfuric acid is added to the volume-reduced battery slag M1 (residual powder M2 remaining after carbon dioxide gas G is generated from the battery slag M1). Therefore, Ni and Co contained in the positive electrode active material in the residual powder M2 can be leached into the sulfuric acid only by adding a small amount of sulfuric acid.

Furthermore, according to the above-described embodiment, Ni and Co, which were not reduced to divalent at the time of carbon dioxide gas generation in the heating step S3, are reduced to divalent with hydrogen peroxide in the first acid leaching step S4, and sulfuric acid is efficiently produced. can be leached into

Then, according to the above-described embodiment, the battery slag M1 taken out after removing the aluminum pieces (impurities I) from the crushed material C is heated in the heating step S3. and inhibiting the reduction of Co. Therefore, Ni and Co contained in the residual powder M2 can be efficiently leached into sulfuric acid in the first acid leaching step S4. Also, the aluminum pieces removed in the removal step S2 can be recovered and effectively used.

In addition, in the above-described embodiment, the crushing step S1, the extraction step S2 and the carbonation step S16 can be omitted. Further, if a step of recovering Ni and/or Co contained in the leachate E1 is provided, part of steps S5 to S15 can be omitted or changed.

Next, examples (Examples 1 to 22) and comparative examples (Comparative Examples 1 and 2) of the valuable metal recovery method according to one embodiment of the present invention will be described. The steps of each example and each comparative example will be described below in correspondence with the above embodiment. In addition, although all the following processes were performed about each Example, the following heating processes were abbreviate|omitted about each comparative example. In each example and each comparative example, not all the steps of the above embodiments were performed.

(Crushing process, removal process)
First, 14.5 g of battery slag taken out from lithium ion secondary battery waste (battery waste) was put into an alumina firing boat and allowed to stand in an alumina cylindrical tube.

(Heating process)
By heating an alumina cylindrical tube, the battery slag was calcined in the atmosphere for 2 hours. The fired battery residue was allowed to cool to room temperature.

(First acid leaching step)
A liquid mixture of 100 ml of sulfuric acid and 5 ml of hydrogen peroxide (concentration: 30%) was added to the battery residue after standing to cool to prepare a leachate. Further, Ni and Co contained in the battery slag were leached out while heating and stirring this leaching solution. After stirring, the leachate was allowed to cool to room temperature.

(First addition step)
An aqueous solution of NaSH (concentration: 250 g/l) was added to the leaching solution that had reached room temperature in the first acid leaching step to produce a treatment solution. The NaSH aqueous solution was added while stirring the treatment liquid until the ORP (oxidation-reduction potential) of the treatment liquid reached 0 mV (vs Ag/AgCl).

(First filtration step)
The treated liquid in the first addition step was filtered to separate into a filtrate and a residue.

(Neutralization process)
An aqueous NaOH solution (25% concentration) was added to the filtrate of the first filtration step to produce a neutralized solution. The NaOH aqueous solution was added until the pH of the neutralization liquid reached 3.5.

(Second addition step)
An aqueous NaSH solution (concentration: 250 g/l) was added to the neutralized liquid to produce a treatment liquid. The NaSH aqueous solution was added while stirring the treatment liquid until the ORP (oxidation-reduction potential) of the treatment liquid reached -400 mV (vs Ag/AgCl).

(Third filtration step)
After confirming that a sufficient amount of black precipitate was formed in the treated liquid in the second addition step, this treated liquid was filtered to separate the filtrate and the residue.

(Second acid leaching step)
100 ml of sulfuric acid (concentration: 0.5 mol/l) and 5 ml of hydrogen peroxide solution (concentration: 30%) were added to the residue from the third filtration step to prepare a leachate. The leachate was heated to 60° C. and stirred for 4 hours. After that, this leachate was allowed to cool to room temperature.

(Fifth filtration step)
The leachate of the second acid leach step was filtered to separate the filtrate and the residue.

(Solvent extraction step)
To 30 l of the filtrate of the fifth filtration step, an extraction solvent (PC-88A content of 20 vol% and diluent kerosene content of 80 vol%) and reverse extraction solvent (sulfuric acid) were added in a mixer settler. . As a result, Ni and Co contained in this filtrate were recovered as sulfates. PC-88A is a metal extractant manufactured by Daihachi Chemical Industry Co., Ltd.

Table 1 shows the type of battery used in each example and each comparative example, the baking temperature of the battery slag in the heating process, the concentration of sulfuric acid used in the first acid leaching process, and the leaching temperature in the first acid leaching process (the temperature of the leachate). heating temperature), leaching time (stirring time of the leaching solution), and recovery rates of Co and Ni in the solvent extraction process are shown for each example and comparative example.

In Table 1, NCM is an NCM battery (that is, a battery using a composite oxide of Ni, Co and Mn as a positive electrode active material). NCA is an NCA-based battery (that is, a battery using a composite oxide of Ni, Co and Al as a positive electrode active material). The recovery rate of Co means "(the mass of Co contained in the sulfate recovered in the solvent extraction step)×100/(the mass of Co contained in the battery slag)". The recovery rate of Ni means "(the mass of Ni contained in the sulfate recovered in the solvent extraction step)×100÷(the mass of Ni contained in the battery slag)". The masses of Co and Ni contained in the sulfate were measured using ICP-AES. The masses of Co and Ni contained in the battery slag were measured by XRF quantitative analysis.

When Example 3 and Comparative Example 1 are compared, the conditions other than the presence or absence of firing are the same, but the difference is whether or not firing is performed. In Example 3 (fired), the Co recovery rate and Ni recovery rate are significantly higher than those of Comparative Example 1 (no firing). When Example 14 and Comparative Example 2 are compared, the conditions other than the presence or absence of firing are the same, but the difference is whether or not firing is performed. In Example 14 (fired), the Co recovery rate and Ni recovery rate are significantly higher than those of Comparative Example 2 (no firing).

Comparing Examples 1 to 4, the conditions are the same except for the leaching temperature, but the leaching temperatures are different from each other. Comparing Examples 12 to 15, conditions other than the leaching temperature are the same, but the leaching temperatures are different. In the examples in which the leaching temperatures were 60°C and 80°C, the Co recovery rate and the Ni recovery rate were significantly higher than those in the examples in which the leaching temperatures were 25°C and 40°C.

Comparing Examples 3 and 5 to 7, the conditions other than the firing temperature are the same, but the firing temperatures are different. Comparing Examples 14 and 16 to 18, the conditions other than the firing temperature are the same, but the firing temperatures are different. In the example in which the sintering temperature is 700°C, the Co recovery rate and the Ni recovery rate are significantly higher than those in the example where the sintering temperature is 600°C. Furthermore, in the examples in which the sintering temperature was 800°C and 900°C, the Co recovery rate and the Ni recovery rate were significantly higher than those in the example in which the sintering temperature was 700°C.

Comparing Examples 3, 8 and 9, the conditions are the same except for the concentration of sulfuric acid, but the concentration of sulfuric acid differs from each other. Comparing Examples 14, 19 and 20, the conditions are the same except for the sulfuric acid concentration, but the sulfuric acid concentration is different. In addition, in the examples in which the sulfuric acid concentrations were 2 mol/l and 2.5 mol/l, the Co recovery rate and the Ni recovery rate were significantly higher than those in the example in which the sulfuric acid concentration was 1.5 mol/l.

Comparing Examples 3, 10 and 11, the conditions are the same except for the leaching time, but the leaching time is different from each other. Comparing Examples 14, 21 and 22, the conditions are the same except for the leaching time, but the leaching time is different from each other. In the example in which the leaching time was 4 hours, the Co recovery rate and the Ni recovery rate were significantly higher than those in the examples in which the leaching time was 2 hours and 3 hours.

The following conclusions can be drawn from the above examples and comparative examples. In the above embodiment, by baking the battery slag M1 in the heating step S3, the Ni and Co contained in the residual powder M2 can be efficiently leached into sulfuric acid in the first acid leaching step S4, and the solvent extraction step S15. Ni and Co can be efficiently recovered in.

Further, in the heating step S3, the battery slag M1 is heated to 700° C. or higher (more preferably 800° C. or higher and 900° C. or lower), the concentration of sulfuric acid used in the first acid leaching step S4 is set to 2 mol/l or higher, and the residual powder M2 is By setting the leaching temperature of 60° C. or higher and setting the leaching time of the residual powder M2 to 4 hours or longer, Ni and Co contained in the residual powder M2 can be efficiently leached into sulfuric acid in the first acid leaching step S4. , Ni and Co can be efficiently recovered in the solvent extraction step S15.

Claims (7)

By heating a battery residue having a positive electrode active material containing Ni or/and Co and a negative electrode active material containing graphite, graphite contained in the negative electrode active material in the battery residue is oxidized to generate carbon dioxide gas. a heating step;
By adding sulfuric acid to the residual powder remaining after the carbon dioxide gas is generated from the battery slag, Ni and/or Co contained in the positive electrode active material in the residual powder is leached into the sulfuric acid to form a leachate. an acid leaching step to
and a recovery step of recovering the Ni and/or Co contained in the leachate. 2. The method for recovering valuable metals according to claim 1, wherein hydrogen peroxide is added to said residual powder together with said sulfuric acid in said acid leaching step. The recovery step includes
an addition step of adding a sulfiding agent to the leachate to generate a treatment liquid;
3. The method according to claim 1, further comprising a filtering step of filtering the treated liquid to separate the treated liquid into a filtrate and a residue containing Ni and/or Co contained in the leachate. A method for recovering the valuable metals described. a crushing step of crushing battery waste to produce crushed products;
a removing step of removing the aluminum pieces from the crushed material and removing the battery slag;
4. The method for recovering valuable metals according to any one of claims 1 to 3, wherein in the heating step, the removed battery slag is heated. The method for recovering valuable metals according to any one of claims 1 to 4, wherein in the heating step, the battery slag is heated to 700°C or higher. 6. The method according to any one of claims 1 to 5, wherein in the acid leaching step, after adding 2 mol/l or more of the sulfuric acid to the residual powder, the leaching solution is heated to 60° C. or more and stirred for 4 hours or more. 1. The method for recovering valuable metals according to 1. By heating a battery residue having a positive electrode active material containing Ni or/and Co and a negative electrode active material containing graphite, graphite contained in the negative electrode active material in the battery residue is oxidized to generate carbon dioxide gas. a heating device;
By adding sulfuric acid to the residual powder remaining after the carbon dioxide gas is generated from the battery slag, Ni and/or Co contained in the positive electrode active material in the residual powder is leached into the sulfuric acid to form a leachate. an acid leaching device that
and a recovery device for recovering the Ni and/or Co contained in the leachate.

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