How to dissolve battery powder in hydrochloric acid

Abstract

Provided is a method for dissolving battery powder in hydrochloric acid, whereby a large amount of battery powder can be dissolved in hydrochloric acid after a single treatment and excellent workability is achieved. In this method for dissolving battery powder in hydrochloric acid, valuable metal-containing battery powder obtained from waste lithium batteries is stirred in hydrochloric acid having a concentration of 50-150 g / L at a mass ratio of 250-1000% relative to hydrogen chloride in the hydrochloric acid to obtain a hydrochloric acid suspension of the battery powder, a predetermined amount of hydrochloric acid is then added to the hydrochloric acid suspension to adjust the concentration of hydrochloric acid in the hydrochloric acid suspension to 150-350 g / L, and the resulting mixture is stirred and adjusted so that the proportion of the battery powder in the hydrochloric acid suspension is 50-200% by mass relative to hydrogen chloride in the hydrochloric acid suspension to obtain a hydrochloric acid solution of the battery powder.

Description

[Technical Field]

[0001] The present invention relates to a method for dissolving battery powder in hydrochloric acid. [Background technology]

[0002] In recent years, with the widespread use of lithium ion batteries, methods have been investigated for recovering valuable metals such as lithium, manganese, nickel, and cobalt from discarded lithium ion batteries and reusing them as positive electrode active materials for the lithium ion batteries.

[0003] Conventionally, when recovering the valuable metals from the waste lithium-ion batteries, the waste lithium-ion batteries are subjected to a heat treatment (roasting) or without a heat treatment, and then crushed and classified to obtain a powder containing the valuable metals (hereinafter referred to as battery powder), which is dissolved in hydrochloric acid, and the valuable metals are leached with hydrochloric acid, and the obtained leachate is subjected to solvent extraction (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4865745 Summary of the Invention [Problem to be solved by the invention]

[0005] The method described in Patent Document 1 has the disadvantage that the amount of battery powder that can be dissolved in hydrochloric acid in one treatment is small, making the work difficult.

[0006] The present invention aims to provide a method for dissolving battery powder in hydrochloric acid that can dissolve a larger amount of the battery powder in hydrochloric acid in one treatment than the method described in Patent Document 1 and has excellent workability. [Means for solving the problem]

[0007] In order to achieve this object, the hydrochloric acid dissolution method of the present invention is a method for dissolving battery powder containing valuable metals obtained from waste lithium batteries in hydrochloric acid, and is characterized by comprising the steps of: supplying the battery powder to hydrochloric acid having a concentration in the range of 50 to 150 g / L at a mass ratio in the range of 250 to 1000% relative to the pure hydrogen chloride content in the hydrochloric acid, and stirring to obtain a hydrochloric acid suspension of the battery powder; and adding a predetermined amount of hydrochloric acid to the hydrochloric acid suspension to adjust the hydrochloric acid concentration in the hydrochloric acid suspension to a range of 150 to 350 g / L, and adjusting the mass ratio of the battery powder in the hydrochloric acid suspension to a range of 50 to 200% relative to the hydrogen chloride in the hydrochloric acid suspension, and stirring to obtain a hydrochloric acid solution of the battery powder.

[0008] In the step of obtaining a hydrochloric acid suspension of the battery powder (suspension step), if the mass ratio of the battery powder to the hydrogen chloride in the hydrochloric acid suspension exceeds 1000%, it becomes difficult to suspend the battery powder, and if the mass ratio of the battery powder to the hydrogen chloride is less than 250%, chlorine gas is likely to be generated from the hydrochloric acid suspension.

[0009] In the step of obtaining a hydrochloric acid solution of the battery powder (dissolution step), if the mass ratio of the battery powder to the hydrogen chloride in the hydrochloric acid suspension and the hydrochloric acid solution exceeds 200%, the valuable metals in the battery powder cannot be dissolved. Also, if the mass ratio of the battery powder to the hydrogen chloride in the dissolution step is less than 50%, there will be an excess of hydrochloric acid remaining after the dissolution reaction of the hydrochloric acid solution, which will require a large amount of base for neutralization, which is a disadvantage.

[0010] In the method for dissolving battery powder in hydrochloric acid of the present invention, the battery powder is first supplied to hydrochloric acid having a concentration in the range of 50 to 150 g / L at a mass ratio of 250 to 1000% relative to the hydrogen chloride in the hydrochloric acid to form a hydrochloric acid suspension. A predetermined amount of hydrochloric acid is then added to the hydrochloric acid suspension to adjust the hydrochloric acid concentration in the hydrochloric acid suspension to a range of 150 to 350 g / L and the mass ratio of battery powder to hydrogen chloride in the hydrochloric acid suspension to a range of 50 to 200%, thereby obtaining a hydrochloric acid solution of the battery powder. As a result, the hydrochloric acid dissolution method of the present invention can dissolve a larger amount of battery powder in hydrochloric acid in a single treatment than the method described in Patent Document 1. Furthermore, the suspension can be prepared under mild conditions, and then the dissolution reaction can be controlled by adding concentrated hydrochloric acid.

[0011] The method for dissolving battery powder in hydrochloric acid of the present invention further comprises the steps of continuously supplying a predetermined amount of hydrochloric acid and a predetermined amount of the battery powder to a suspension tank having a predetermined volume, suspending the battery powder in hydrochloric acid having a concentration in the range of 50 to 150 g / L at a mass ratio in the range of 250 to 1000% relative to the hydrogen chloride in the hydrochloric acid, thereby obtaining a first hydrochloric acid suspension of the battery powder; and continuously supplying the first hydrochloric acid suspension of the battery powder to a series of dissolution tanks comprising a plurality of dissolution tanks each having a predetermined volume arranged in series. On the other hand, it is preferable to include the steps of continuously feeding hydrochloric acid into at least one of the continuous dissolution tanks, adjusting the concentration of hydrochloric acid in the hydrochloric acid suspension to a range of 150 to 350 g / L, and adjusting the mass ratio of battery powder to hydrogen chloride in the hydrochloric acid suspension to a range of 50 to 200%, thereby obtaining a second hydrochloric acid suspension of the battery powder, and transferring the second hydrochloric acid suspension of battery powder from the most upstream tank of the continuous dissolution tanks to tanks successively downstream, thereby obtaining a hydrochloric acid solution of the battery powder.

[0012] With this configuration, the second hydrochloric acid suspension is stirred while being transferred from the most upstream tank of the series of dissolution tanks to the tanks located downstream in succession, thereby efficiently promoting dissolution and enabling the battery powder to be treated continuously without stopping the reaction.

[0013] The method for dissolving battery powder in hydrochloric acid of the present invention preferably further comprises a first roasting step of roasting the battery powder at 300° C. or higher together with at least one selected from the group consisting of hydrogen and carbon monoxide.

[0014] The method for dissolving battery powder in hydrochloric acid of the present invention preferably further comprises a second roasting step of roasting the battery powder together with carbon at 600° C. or higher. The carbon may be added optionally, or may be carbon that is originally contained in the battery powder.

[0015] The method for dissolving battery powder in hydrochloric acid of the present invention preferably further includes a third roasting step of roasting the battery powder together with aluminum at 650°C or higher. The aluminum may be added optionally, or may be aluminum that is originally contained in the battery powder. When the method for dissolving battery powder in hydrochloric acid of the present invention includes any one of the first to third roasting steps, the amount of chlorine gas generated in the step of obtaining a hydrochloric acid solution of the battery powder can be further reduced.

[0016] In the method for dissolving battery powder in hydrochloric acid of the present invention, preferably, in the step of obtaining a hydrochloric acid suspension of battery powder or the step of obtaining a hydrochloric acid solution, hydrogen generated by the acid dissolution of aluminum is added and utilized as a reducing gas in any of the first to third roasting steps. If necessary, chlorine gas generated in the step of obtaining a hydrochloric acid suspension of battery powder or the step of obtaining a hydrochloric acid solution is removed by a scrubber, and when hydrogen is utilized in any of the first to third roasting steps, the amount of chlorine gas generated in the step of obtaining a hydrochloric acid solution of battery powder can be further reduced.

[0017] The method for dissolving battery powder in hydrochloric acid of the present invention preferably further includes a step of adding carbon or aluminum to at least one selected from the group consisting of the hydrochloric acid suspension of battery powder and the hydrochloric acid solution. When carbon or aluminum is originally contained in the battery powder, or when carbon or aluminum is additionally added to at least one selected from the group consisting of the step of obtaining a hydrochloric acid solution and the group consisting of the hydrochloric acid solution and is present in the hydrochloric acid solution of battery powder, the amount of chlorine gas generated in the step of obtaining a hydrochloric acid solution of battery powder can be reduced. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a flowchart showing a method for dissolving battery powder in hydrochloric acid according to the present invention. [Figure 2] FIG. 1 is a system configuration diagram showing an example of an apparatus configuration used in a method for dissolving battery powder in hydrochloric acid according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0020] The method for dissolving battery powder in hydrochloric acid according to this embodiment is a method for dissolving powder (battery powder) containing valuable metals obtained from waste lithium ion batteries in hydrochloric acid.

[0021] In the method for dissolving battery powder in hydrochloric acid according to this embodiment, the waste lithium ion batteries refer to used lithium ion batteries that have reached the end of their life as battery products, lithium ion batteries that have been discarded as defective products in the manufacturing process, and residual positive electrode materials that have been used in the manufacturing process to produce products.

[0022] In the method for dissolving battery powder in hydrochloric acid according to this embodiment, as shown in FIG. 1 , the waste lithium-ion batteries are pretreated in STEP 1. In the pretreatment, if the waste lithium-ion batteries are used lithium-ion batteries whose battery life as a battery product has expired, first, a discharge treatment is performed to discharge all remaining charge. Next, an opening is formed in the casing of the waste lithium-ion battery, and the battery is then heated (roasted), for example, at a temperature in the range of 100 to 450°C. After the heat treatment, or without the heat treatment, the waste lithium-ion batteries are pulverized using a pulverizer such as a hammer mill or jaw crusher, and the casing, current collector, and other components of the waste lithium-ion batteries are removed (classified) by sieving, thereby obtaining battery powder in STEP 2 as a powder containing valuable metals.

[0023] Alternatively, the waste lithium ion batteries after the discharge treatment may be pulverized in the pulverizer, the casings, current collectors, etc. may be removed by sieving, and then the resulting pulverized battery powder may be subjected to a heat treatment at a temperature within the above range.

[0024] Furthermore, when the waste lithium-ion batteries are residual positive electrode materials or the like that have been used in commercialization in a manufacturing process, the batteries may be heat-treated at a temperature within the above range without being subjected to the discharge treatment and the formation of openings, and then pulverized in the pulverizer, and the current collectors and the like may be removed by sieving to obtain the battery powder (positive electrode powder), or the batteries may be pulverized in the pulverizer, the current collectors may be removed by sieving, and then heat-treated at a temperature within the above range to obtain the battery powder.

[0025] The battery powder may be roasted at 300°C or higher with at least one selected from the group consisting of hydrogen and carbon monoxide (first roasting step), may be roasted at 600°C or higher with carbon (second roasting step), or may be roasted at 650°C or higher with aluminum (third roasting step).

[0026] In the method for dissolving battery powder in hydrochloric acid according to this embodiment, the battery powder is suspended in hydrochloric acid in STEP 3 to obtain a hydrochloric acid suspension in STEP 4. Carbon or aluminum may be added to the hydrochloric acid suspension. Next, in STEP 5, hydrochloric acid is added to the hydrochloric acid suspension, and the battery powder contained in the hydrochloric acid suspension is dissolved in hydrochloric acid to obtain a hydrochloric acid solution of battery powder. Carbon or aluminum may be added to the hydrochloric acid solution. In at least one step selected from the group consisting of STEP 3 and STEP 5, hydrogen generated during the acid dissolution of aluminum foil, which is a component of the battery, or aluminum metal added to the suspension is separated from chlorine gas by a scrubber as necessary and can be added and used as a reducing gas in any of the first to third roasting steps.

[0027] After the hydrochloric acid solution is neutralized, manganese, cobalt, and nickel are sequentially extracted from the valuable metals by solvent extraction in STEP 7. Then, in STEP 8, an aqueous lithium salt solution can be obtained as the extraction residue. The aqueous lithium salt solution can be reacted with carbon dioxide gas or a carbonate compound to obtain lithium carbonate.

[0028] The method for dissolving battery powder in hydrochloric acid according to this embodiment includes steps 3 to 6, and can be carried out using a hydrochloric acid dissolution apparatus 1 shown in FIG. 2, for example.

[0029] The hydrochloric acid dissolution apparatus 1 comprises a suspension tank 2 in which battery powder obtained from waste lithium-ion batteries is suspended in hydrochloric acid to obtain a hydrochloric acid suspension of the battery powder, and a plurality of dissolution tanks 3, 4, 5, and 6 arranged in series in which the battery powder is dissolved in hydrochloric acid having a higher concentration than the hydrochloric acid contained in the hydrochloric acid suspension. In this embodiment, the plurality of dissolution tanks 3, 4, 5, and 6 arranged in series are referred to as a series of dissolution tanks. Note that, although the series of dissolution tanks in FIG. 2 comprises four dissolution tanks, the total number of the series of dissolution tanks is not limited. From the viewpoint of equipment costs, etc., it is practical to have preferably 2 to 6 dissolution tanks, more preferably 2 to 5 dissolution tanks, and even more preferably 3 to 5 dissolution tanks.

[0030] To the suspension tank 2, hydrochloric acid and battery powder are supplied.

[0031] The series of dissolution tanks are arranged in series in a stepped manner, with the suspension tank 2 side being the upstream side, and dissolution tanks 3, 4, 5, and 6 arranged in this order from the upstream side.

[0032] Hydrochloric acid may be supplied to dissolution tank 3. Hydrochloric acid may also be supplied to each of dissolution tanks 4 to 6, which will be described later, provided that hydrochloric acid is supplied to at least one of dissolution tanks 3 to 6.

[0033] The suspension tank 2 is also provided with a hydrochloric acid suspension extraction conduit 21 for extracting the hydrochloric acid suspension of the battery powder by overflowing it from the liquid surface in the suspension tank 2, hydrochloric acidThe suspension discharge conduit 21 is connected to the adjacent dissolution tank 3. On the other hand, the dissolution tanks 3, 4, and 5 are provided with hydrochloric acid suspension discharge conduits 31, 41, and 51, respectively, for discharging the hydrochloric acid suspension of battery powder by overflowing it from the liquid surface in the dissolution tanks 3, 4, and 5. hydrochloric acid Suspension extraction conduit 31 , 41 , 51 are connected to the lower portions of the adjacent dissolution tanks 4, 5, and 6, respectively. Dissolution tank 6 is also provided with a hydrochloric acid solution extraction conduit 61 for extracting the hydrochloric acid solution of the battery powder by overflowing it from the liquid surface in dissolution tank 6.

[0034] Next, a method for dissolving battery powder in hydrochloric acid using the hydrochloric acid dissolving apparatus 1 according to this embodiment will be described.

[0035] In the hydrochloric acid dissolution apparatus 1, first, hydrochloric acid having a concentration in the range of 50 to 150 g / L, for example, 117 g / L, is continuously supplied to a 5 L suspension tank 2 at a flow rate in the range of 2.5 to 10 L / hour, for example, 5 L / hour, while the battery powder obtained in STEP 2 is continuously supplied to the suspension tank 2 at a feed rate in the range of 1 to 2 kg / hour, for example, 1.6 kg / hour. As a result, in the suspension tank 2, a first hydrochloric acid suspension of the battery powder can be obtained, in which the battery powder is suspended in hydrochloric acid having a concentration in the range of 50 to 150 g / L, for example, 117 g / L, at a mass ratio in the range of 250 to 1000%, for example, a mass ratio of 270%, relative to the hydrogen chloride in the hydrochloric acid.

[0036] At this time, the suspension tank 2 has a capacity that is filled up in, for example, one hour when hydrochloric acid is continuously supplied at a flow rate within the above range, for example, 5 L / hour, and the battery powder is continuously supplied at a supply rate within the above range, for example, 1.6 kg / hour. As a result, when the suspension tank 2 is empty, the first hydrochloric acid suspension will be filled up in, for example, one hour after the start of the supply of the hydrochloric acid and the battery powder. hydrochloric acidThe first hydrochloric acid suspension is supplied to the adjacent dissolution tank 3 by overflowing through the suspension discharge conduit 21. Furthermore, even when the first hydrochloric acid suspension from the previous treatment remains in the suspension tank 2, the remaining first hydrochloric acid suspension is replaced with new first hydrochloric acid suspension after the time within the above range, for example, one hour, from the start of supply of the hydrochloric acid and battery powder, and the new first hydrochloric acid suspension is hydrochloric acid The suspension is supplied to the adjacent dissolution tank 3 through a suspension discharge conduit 21 .

[0037] Hydrochloric acid having a higher concentration than the hydrochloric acid supplied to the suspension tank 2, for example, 35 mass % (410 g / L), may be continuously supplied to the dissolution tank 3 at a flow rate of, for example, 3 to 10 L / hour, specifically, 5 L / hour. As a result, in the dissolution tank 3 having a volume of, for example, 10 L, the battery powder is suspended in hydrochloric acid having a concentration of 150 to 350 g / L, for example, 270 g / L, at a mass ratio of 50 to 200%, for example, 60%, relative to the hydrogen chloride in the hydrochloric acid, thereby obtaining a second hydrochloric acid suspension of the battery powder.

[0038] At this time, the dissolution tank 3 hydrochloric acid The first hydrochloric acid suspension is continuously supplied from the suspension discharge conduit 21 at a flow rate of, for example, 5 L / hour, and the dissolution tank 3 has a capacity (10 L in this example) that becomes full in, for example, one hour when hydrochloric acid is continuously supplied at a flow rate within the above range, for example, 5 L / hour. As a result, when the dissolution tank 3 is empty, the second hydrochloric acid suspension will overflow after the above range of time, for example, one hour, from the start of supply of the first hydrochloric acid suspension and hydrochloric acid. Also, even when the second hydrochloric acid suspension from the previous treatment remains in the dissolution tank 3, the remaining second hydrochloric acid suspension will be replaced with new second hydrochloric acid suspension after the above range of time, for example, one hour, from the start of supply of the first hydrochloric acid suspension and hydrochloric acid, and the new second hydrochloric acid suspension will overflow. The overflowed second hydrochloric acid suspension is hydrochloric acid The suspension is supplied to the adjacent dissolution tank 4 through the suspension discharge conduit 31. At this time, the dissolution tank 4 is hydrochloric acidWhen the second hydrochloric acid suspension is continuously supplied from the suspension discharge conduit 31 at a flow rate in the range of 2.5 to 10 L / hour, for example, 5 L / hour, the capacity is such that the second hydrochloric acid suspension will reach full capacity in a time period in the range of 0.5 to 1.5, for example, 1 hour. As a result, when the dissolution tank 4 is empty, the second hydrochloric acid suspension will overflow after a time period in the range, for example, 1 hour, from the start of supply of the second hydrochloric acid suspension. Also, even when the second hydrochloric acid suspension from the previous treatment remains in the dissolution tank 4, the remaining second hydrochloric acid suspension will be replaced with new second hydrochloric acid suspension after a time period in the range, for example, 1 hour, from the start of supply of the second hydrochloric acid suspension, and the new second hydrochloric acid suspension will overflow. The overflowed second hydrochloric acid suspension is hydrochloric acid The suspension is supplied to the adjacent dissolution tank 5 through a suspension discharge conduit 41 .

[0039] The dissolution tank 5 has exactly the same configuration as the dissolution tank 4, and new second hydrochloric acid suspension overflows after the time in the above range, for example, one hour, from the start of supply of the second hydrochloric acid suspension. The overflowed second hydrochloric acid suspension is hydrochloric acid The suspension is supplied to the adjacent dissolution tank 6 through a suspension discharge conduit 51 .

[0040] Dissolution tank 6 has exactly the same configuration as dissolution tanks 4 and 5, and new second hydrochloric acid suspension overflows after the time within the aforementioned range, for example, one hour, from the start of supply of the second hydrochloric acid suspension. The overflowing second hydrochloric acid suspension is a hydrochloric acid solution of the battery powder in which substantially all of the valuable metals in the battery powder have been dissolved in hydrochloric acid, and this hydrochloric acid solution is hydrochloric acid The solution is taken out through the dissolving solution taking-out conduit 61. Hydrochloric acid solution In the extraction conduit 61, the elution rates of cobalt, nickel, manganese, and lithium contained in the battery powder into the dissolution solution were all 98% or more.

[0041] In the hydrochloric acid dissolution apparatus 1, hydrochloric acid is further added to the first suspension obtained in the suspension tank 2 in the dissolution tank 3 to form a second suspension. The second suspension is transferred sequentially through the serially arranged dissolution tanks 3, 4, 5, and 6 over a period of 2 to 6 hours. Each dissolution tank 3, 4, 5, and 6 is configured so that the solution overflows into the next tank through its respective dissolution liquid outlet conduit. Therefore, the second suspension can be sufficiently stirred while remaining in each dissolution tank 3, 4, 5, and 6, and as much of the second suspension as possible can be dissolved in hydrochloric acid in a single treatment. This results in a larger amount of battery powder than the method described in Patent Document 1, resulting in excellent workability. [Explanation of symbols]

[0042] 2...Suspension tank, 3, 4, 5, 6...Dissolution tank, 21, 31, 41, 51... Hydrochloric acid suspension extraction conduit, 61... Hydrochloric acid Lysate extraction conduit.

Claims

1. A method for dissolving battery powder in hydrochloric acid, which comprises dissolving battery powder containing valuable metals obtained from waste lithium batteries in hydrochloric acid, a step of supplying the battery powder to hydrochloric acid having a concentration in the range of 50 to 150 g / L at a mass ratio in the range of 250 to 1000% relative to the hydrogen chloride in the hydrochloric acid, and stirring the battery powder to obtain a hydrochloric acid suspension; a step of adding a predetermined amount of hydrochloric acid to the hydrochloric acid suspension to adjust the concentration of hydrochloric acid in the hydrochloric acid suspension to a range of 150 to 350 g / L, and adjusting the mass ratio of the battery powder in the hydrochloric acid suspension to the hydrogen chloride in the hydrochloric acid suspension to a range of 50 to 200%, and stirring the mixture to obtain a hydrochloric acid solution of the battery powder.

2. The method for dissolving battery powder in hydrochloric acid according to claim 1, a step of continuously supplying a predetermined amount of hydrochloric acid and a predetermined amount of the battery powder to a suspension tank having a predetermined volume, suspending the battery powder in hydrochloric acid having a concentration in the range of 50 to 150 g / L at a mass ratio in the range of 250 to 1000% relative to the hydrogen chloride in the hydrochloric acid, thereby obtaining a first hydrochloric acid suspension of the battery powder; a step of continuously supplying the first hydrochloric acid suspension of the battery powder from a suspension tank to a series dissolution tank comprising a plurality of dissolution tanks each having a predetermined capacity arranged in series, while continuously supplying hydrochloric acid to the series dissolution tank, adjusting the concentration of hydrochloric acid in the hydrochloric acid suspension to a range of 150 to 350 g / L and adjusting the mass ratio of battery powder to hydrogen chloride in the hydrochloric acid suspension to a range of 50 to 200%, thereby obtaining a second hydrochloric acid suspension of the battery powder; a step of transferring the second hydrochloric acid suspension of the battery powder from the most upstream tank of the series of dissolution tanks to successively downstream tanks, thereby obtaining a hydrochloric acid solution of the battery powder.

3. The method for dissolving battery powder in hydrochloric acid according to claim 1, The method for dissolving battery powder in hydrochloric acid further comprises a first roasting step of roasting the battery powder at 300°C or higher together with at least one selected from the group consisting of hydrogen and carbon monoxide.

4. The method for dissolving battery powder in hydrochloric acid according to claim 1, The method for dissolving battery powder in hydrochloric acid further comprises a second roasting step of roasting the battery powder together with carbon at 600°C or higher.

5. The method for dissolving battery powder in hydrochloric acid according to claim 1, The method for dissolving battery powder in hydrochloric acid further comprises a third roasting step of roasting the battery powder together with aluminum at 650°C or higher.

6. The method for dissolving battery powder in hydrochloric acid according to claim 3, a step of obtaining a hydrochloric acid suspension of the battery powder; and a step of obtaining a hydrochloric acid solution.

7. The method for dissolving battery powder in hydrochloric acid according to claim 4, a step of obtaining a hydrochloric acid suspension of battery powder; and a step of obtaining a hydrochloric acid solution of battery powder.

8. The method for dissolving battery powder in hydrochloric acid according to claim 5, a step of obtaining a hydrochloric acid suspension of battery powder and a step of obtaining a hydrochloric acid solution, and hydrogen generated in at least one step selected from the group consisting of the step of obtaining a hydrochloric acid suspension of battery powder and the step of obtaining a hydrochloric acid solution is added and utilized as a reducing gas in the third roasting step.

9. The method for dissolving battery powder in hydrochloric acid according to any one of claims 1 to 8, The method for dissolving battery powder in hydrochloric acid further comprises the step of adding carbon to at least one selected from the group consisting of the hydrochloric acid suspension of the battery powder and the hydrochloric acid solution.

10. The method for dissolving battery powder in hydrochloric acid according to any one of claims 6 to 8, The method for dissolving battery powder in hydrochloric acid further comprises the step of adding carbon to at least one selected from the group consisting of the hydrochloric acid suspension of the battery powder and the hydrochloric acid solution.

11. The method for dissolving battery powder in hydrochloric acid according to any one of claims 1 to 5, The method for dissolving battery powder in hydrochloric acid further comprises the step of adding aluminum to at least one selected from the group consisting of the hydrochloric acid suspension of the battery powder and the hydrochloric acid solution.

12. The method for dissolving battery powder in hydrochloric acid according to any one of claims 6 to 8, The method for dissolving battery powder in hydrochloric acid further comprises the step of adding aluminum to at least one selected from the group consisting of the hydrochloric acid suspension of the battery powder and the hydrochloric acid solution.

13. The method for dissolving battery powder in hydrochloric acid according to claim 9, The method for dissolving battery powder in hydrochloric acid further comprises the step of adding aluminum to at least one selected from the group consisting of the hydrochloric acid suspension of the battery powder and the hydrochloric acid solution.

14. The method for dissolving battery powder in hydrochloric acid according to claim 10, The method for dissolving battery powder in hydrochloric acid further comprises the step of adding aluminum to at least one selected from the group consisting of the hydrochloric acid suspension of the battery powder and the hydrochloric acid solution.

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