Treatment method of lithium ion battery waste

Abstract

The present invention relates to a method for treating lithium ion battery waste, in which a leaching solution in which at least cobalt and nickel are dissolved is obtained by performing wet treatment on the lithium ion battery waste. The method comprises the following steps: a wet treatment step of adding and mixing at least one compound (1) selected from the group consisting of ammonia and salts thereof, and amine compounds and salts thereof to the lithium ion battery waste to obtain a leaching solution in which at least cobalt and nickel are dissolved; and a solid-liquid separation step in which, after the wet treatment step, at least a portion of the metal that is insoluble in the leachate is removed by solid-liquid separation.

Description

Technical Field

[0001] This invention relates to a method for treating lithium-ion battery waste. Background Technology

[0002] From the perspective of the SDGs (Sustainable Development Goals), the recycling and reuse of valuable metals such as cobalt and nickel from lithium-ion battery waste has been widely discussed.

[0003] In recovering valuable metals such as cobalt and nickel from lithium-ion battery waste, the waste is processed through roasting and crushing. The resulting lithium-ion battery powder is added to an acidic solution to obtain a leaching solution containing dissolved lithium, copper, cobalt, nickel, iron, aluminum, manganese, etc. Next, through repeated solid-liquid separation or solvent extraction, a solution containing the desired valuable metal, such as cobalt or nickel, is obtained. Finally, nickel and cobalt are recovered through electrolysis of the solutions.

[0004] For example, Patent Document 1 below describes a method for treating lithium-ion battery waste, which includes: The initial neutralization step involves obtaining an acidic solution containing at least cobalt, nickel, manganese, and aluminum through wet processing of lithium-ion battery waste. The pH is neutralized to 4.0–6.0, causing some of the aluminum to precipitate. This precipitate is then removed through solid-liquid separation. Post-neutralization step: After the pre-neutralization step, the pH is neutralized to above 11.0, leaving the remaining aluminum in the liquid. The neutralized residue containing cobalt, nickel and manganese is obtained through solid-liquid separation.

[0005] [Previous Technology] [Previous Technical Documents] [Patent Literature] Japanese Patent Application Publication No. 2020-180362. Summary of the Invention

[0006] [The problem that the invention aims to solve] After careful study of the processing method described in the aforementioned Patent Document 1, the inventors realized the following: it is difficult to efficiently remove aluminum or iron, which are the objects to be removed, from the leaching solution, and there is still room for further improvement in order to leach the desired valuable metals such as nickel and cobalt at a high leaching rate.

[0007] In view of the above, the objective of this invention is to provide a method for treating lithium-ion battery waste with excellent recovery rates of desirable valuable metals such as nickel and cobalt.

[0008] [Technical means to solve the problem] This problem can be solved by the following configuration. That is, the present invention relates to a method for treating lithium-ion battery waste (1), which obtains a leachate containing at least dissolved cobalt and nickel by wet treatment of the lithium-ion battery waste, characterized by comprising the following steps: Wet treatment steps: adding at least one compound selected from the group consisting of ammonia and its salts, and amine compounds and their salts to the lithium-ion battery waste (1) and mixing, thereby obtaining the leaching solution containing at least the cobalt and the nickel dissolved in it; and Solid-liquid separation step: After the wet treatment step, at least a portion of the metal that is not soluble in the leaching solution is removed by solid-liquid separation.

[0009] The preferred method for treating lithium-ion battery waste (2) is that, in the method for treating lithium-ion battery waste (1), in the wet treatment step, in addition to the compound (1), acid is added and mixed.

[0010] The preferred method for treating lithium-ion battery waste (3) is wherein, in the method for treating lithium-ion battery waste (2), the acid is at least one compound (2) selected from the group consisting of monocarboxylic acid organic acids and inorganic acids.

[0011] The preferred method for treating lithium-ion battery waste (4) is that, in any one of the methods for treating lithium-ion battery waste (1) to (3), the compound (1) is at least one compound selected from the group consisting of amine compounds having an amino group and their salts.

[0012] The preferred method for treating lithium-ion battery waste (5) is that, in any one of the methods for treating lithium-ion battery waste (1) to (4), the compound (1) is at least one compound selected from the group consisting of chelate amine compounds having two or more amino groups and their salts.

[0013] The preferred method for treating lithium-ion battery waste (6) is that, in any one of the methods for treating lithium-ion battery waste (1) to (5), the lithium-ion battery waste contains aluminum, and at least a portion of the aluminum is removed in the solid-liquid separation step.

[0014] The preferred method for treating lithium-ion battery waste (7) is that, in any one of the methods for treating lithium-ion battery waste (1) to (6), the lithium-ion battery waste contains iron, and at least a portion of the iron is removed in the solid-liquid separation step.

[0015] The preferred method for treating lithium-ion battery waste (8) is that, in any one of the methods for treating lithium-ion battery waste (1) to (7), the lithium-ion battery waste contains manganese, and at least a portion of the manganese is removed in the solid-liquid separation step.

[0016] [The effects of the invention] According to the lithium-ion battery waste treatment method of the present invention, by including a wet treatment step, aluminum, iron or manganese other than cobalt and nickel can be removed by simple operations such as solid-liquid separation. Therefore, the desired valuable metals such as nickel and cobalt can be recovered with a high recovery rate. The wet treatment step is to add and mix at least one compound selected from the group consisting of ammonia and its salts and amine compounds and their salts to obtain a leachate containing at least cobalt and nickel dissolved in it. Detailed Implementation

[0017] The present invention is a method for treating lithium-ion battery waste by wet processing to obtain a leachate containing at least dissolved cobalt and nickel, comprising at least a wet processing step and a solid-liquid separation step.

[0018] Lithium-ion battery waste refers to the waste from lithium-ion batteries used in electric vehicles, mobile phones, personal computers, and other devices. Generally speaking, lithium-ion batteries consist of a positive electrode with lithium cobalt oxide as the main active material, a negative electrode with special carbon as the main active material, and spacers, which are layered or swirled in an electrolyte state and then disposed within an outer casing material such as aluminum.

[0019] Generally, lithium-ion battery waste undergoes pretreatment such as roasting or crushing before the wet treatment step. In roasting, the lithium-ion battery is heated to, for example, 500–1000°C and maintained for several hours. This heating can be carried out in a furnace or in the atmosphere. In crushing, a sample mill, hammer mill, or other pulverizer is used. In this invention, pretreatment other than roasting and crushing can also be performed before the wet treatment step, as needed. For example, after roasting or crushing, the lithium-ion battery waste can be made into a fine powder of lithium-ion battery powder, which can then be contacted, for example, with ion-exchanged water, thereby recovering a certain amount of lithium from the lithium-ion battery powder.

[0020] Lithium-ion battery waste contains lithium, copper, cobalt, nickel, iron, aluminum, manganese, etc. The concentration of each metal contained in the lithium-ion battery waste can be determined, for example, by the following method. Specifically, after pretreatment such as roasting and pulverizing, the lithium-ion battery waste is made into a fine powder of lithium-ion battery powder. The lithium-ion battery powder is then added to aqua regia (hydrochloric acid / nitric acid = 3 / 1 solution) to obtain a leaching solution containing dissolved lithium, copper, cobalt, nickel, iron, aluminum, manganese, etc. The leaching solution is preferably obtained by leaching the lithium-ion battery powder with an acidic solution such as aqua regia. The pH of the leaching solution after adding aqua regia is preferably, for example, 0.0 to 1.0. Examples of conditions for obtaining the leaching solution include: adding 1.0 to 10.0 g of lithium-ion battery powder to every 50.0 to 500.0 g of aqua regia, and leaching is carried out at 25 to 80°C for 1 to 72 hours with a stirring speed of 250 to 1500 rpm. After leaching, solid-liquid separation is performed using a suction filter or similar device, and the concentration of each metal in the obtained filtrate is measured. The concentration of each metal in the leaching solution can be measured, for example, using an ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer). In this invention, the recovery rates of cobalt and nickel are calculated based on the leaching solution (filtrate) obtained by adding aqua regia to lithium-ion battery waste. This will be described later.

[0021] (Wet treatment steps) In the wet treatment step, at least one compound selected from the group consisting of ammonia and its salts, and amine compounds and their salts is added to the lithium-ion battery waste and mixed to obtain a leaching solution containing at least cobalt and nickel.

[0022] Compound (1) is at least one compound selected from the group consisting of ammonia and its salts, and amine compounds and their salts. Examples of ammonia salts (ammonium salts) include ammonium chloride. Examples of amine compounds include ethylenediamine, tris(2-ethylamino)amine, imidazole, 2-piperazine, triethanolamine, L-lysine, and aminoguanidine. Examples of amine compound salts include ethylenediamine dihydrochloride, 2-piperazine hydrochloride, 2-piperazine hydrochloride monohydrate, cysteine ​​hydrochloride, triethanolamine hydrochloride, L-lysine hydrochloride, and aminoguanidine hydrochloride. Ammonia and its salts, as well as amine compounds and their salts, can be used alone or in combination. For example, ammonium salts can be combined with ammonia, or amine compound salts can be combined with ammonia. More specifically, for example, ammonium chloride and ammonia can be combined, as can 2-piperazine hydrochloride monohydrate and ammonia, cysteine ​​hydrochloride and ammonia, ethylenediamine dihydrochloride and ammonia, triethanolamine hydrochloride and ammonia, L-lysine hydrochloride and ammonia, or aminoguanidine hydrochloride and ammonia.

[0023] In this invention, among compound (1), at least one compound is preferably selected from the group consisting of amine compounds having an amino group and their salts, and more preferably from the group consisting of chelate amine compounds having two or more amino groups and their salts. Specifically, for example, when ethylenediamine, tris(2-ethylamino)amine, 2-piperazine hydrochloride monohydrate, ethylenediamine dihydrochloride, or L-lysine hydrochloride are used, the recovery rate of desired valuable metals such as nickel and cobalt is further improved, which is therefore preferred.

[0024] To improve the recovery rate of desired valuable metals such as nickel and cobalt, it is preferable that, in the wet processing step, an acid is added to the lithium-ion battery waste in addition to compound (1) and the mixture is then stirred, thereby removing at least a portion of the metals other than cobalt and nickel. More preferably, at least one compound (2) selected from the group consisting of monocarboxylic acid organic acids and inorganic acids is added as an acid and stirred, thereby removing at least a portion of the metals other than cobalt and nickel. Examples of monocarboxylic acid organic acids include formic acid and acetic acid. Examples of inorganic acids include hydrochloric acid and hydrobromic acid.

[0025] When compound (2) is added in addition to compound (1) during the wet processing step, it is preferable to set the molar ratio of compound (2):compound (1) to 1:6, more preferably 1:1 to 1:2. By setting it within this range, the recovery rate of desired valuable metals such as nickel and cobalt can be further improved.

[0026] To improve the recovery rate of desired valuable metals such as nickel and cobalt, it is preferable to adjust the pH of the leaching solution after adding only compound (1), or the leaching solution after adding both compound (1) and compound (2), to 3.0 to 12.5, more preferably to 9.5 to 11.0, during the wet treatment step. Furthermore, it is preferable to set the temperature of the leaching solution to 25 to 80°C and to stir at a stirring speed of 500 to 1000 rpm for 8 to 24 hours.

[0027] (Solid-liquid separation steps) As a removal method for removing at least a portion of the insoluble metals from the leachate obtained in the wet treatment step, an example example is a method of separating the leachate containing at least dissolved cobalt and nickel from the precipitate, such as aluminum or iron, which is the object of removal, by solid-liquid separation. In the lithium-ion battery waste treatment method of the present invention, desirable valuable metals such as nickel and cobalt can be recovered with a high recovery rate. Specifically, for example, when a solid-liquid separation step is performed after the wet treatment step, the recovery rate of cobalt and nickel obtained thereafter is 50% or more, and more preferably 70% or more. Furthermore, in the present invention, the recovery rate of cobalt and nickel can be calculated by the following formula (1).

[0028] (Recovery rate of each metal (%)) = (Metal concentration in the leachate (filtrate) obtained after wet treatment) / (Metal concentration in the leachate (filtrate) after adding aqua regia to lithium-ion battery waste) × 100... Equation (1).

[0029] In the lithium-ion battery waste treatment method of the present invention, when the lithium-ion battery waste contains aluminum, and at least a portion of the aluminum is removed in the solid-liquid separation step, the aluminum recovery rate calculated by formula (1) becomes lower, that is, the residual amount of aluminum becomes less, which is preferable. Specifically, for example, the residual amount of aluminum after the wet treatment step is 30% or less, and more preferably 10% or less.

[0030] In the lithium-ion battery waste treatment method of the present invention, when the lithium-ion battery waste contains iron, and at least a portion of the iron is removed in the solid-liquid separation step, the iron recovery rate calculated by formula (1) becomes lower, that is, the iron residue rate becomes lower, which is preferable. Specifically, for example, the iron residue rate after the wet treatment step is 30% or less, and more preferably 10% or less.

[0031] In the lithium-ion battery waste treatment method of the present invention, when the lithium-ion battery waste contains manganese, and at least a portion of the manganese is removed in the solid-liquid separation step, the manganese recovery rate calculated by formula (1) becomes lower, that is, the manganese residue rate becomes lower, which is preferable. Specifically, for example, the manganese residue rate after the wet treatment step is 30% or less, and more preferably 10% or less.

[0032] In the lithium-ion battery waste treatment method of the present invention, even when the lithium-ion battery waste contains lithium, the lithium recovery rate calculated by formula (1) in the solid-liquid separation step is relatively high, which is preferred. Specifically, for example, the lithium recovery rate after the wet treatment step is 10% or more, and more preferably 35% or more.

[0033] In the lithium-ion battery waste treatment method of the present invention, even when the lithium-ion battery waste contains copper, the copper recovery rate calculated by formula (1) in the solid-liquid separation step is relatively high, which is preferred. Specifically, for example, the copper recovery rate after the wet treatment step is 10% or more, and more preferably 35% or more.

[0034] In the lithium-ion battery waste treatment method of the present invention, when a solid-liquid separation step is performed after the wet treatment step, the recovery rate of cobalt and nickel among the metals contained in the subsequently obtained leachate (filtrate) is high, while the residual rate of unwanted metals, particularly aluminum and iron, is low. Therefore, the lithium-ion battery waste treatment method of the present invention is particularly useful as a method for recovering cobalt and nickel from lithium-ion battery waste. For example, an extraction operation can be performed using an extractant well known in the industry, thereby ultimately recovering only cobalt or only nickel from the filtrate obtained after the wet treatment step.

[0035] The following describes an example of an embodiment of the present invention, but the present invention is not limited thereto.

[0036] (Determination of the concentration of various metals contained in lithium-ion battery waste) 1.0 g of lithium-ion battery powder obtained by roasting and crushing lithium-ion battery waste was added to 50.0 g of aqua regia (hydrochloric acid / nitric acid = 3 / 1) and mixed at 25°C for 24 hours with a stirring speed of 500–750 rpm to obtain a leachate. Solid-liquid separation of the leachate was performed using a suction filter, and the metal concentration of the obtained filtrate was determined. Furthermore, ICP was used to determine the metal concentration. The results are shown in Table 1.

[0037] [Table 1] (Wet processing steps, solid-liquid separation steps) 1.0 g of lithium-ion battery powder was added to 50.0 g of treated water and mixed. The treated water was prepared by adjusting only ion-exchanged water and compound (1), or ion-exchanged water, compound (1) and compound (2) in the proportions shown in Tables 2 and 3. After mixing the lithium battery powder and treated water at 25°C for 24 hours and stirring at 500-750 rpm (wet treatment step), solid-liquid separation was performed using a suction filter (solid-liquid separation step), and the metal concentration of the obtained filtrate was determined. ICP was used for concentration determination. The results are shown in Tables 2 and 3. Furthermore, the recovery rates of each metal in Tables 2 and 3 were calculated using the above formula (1) and evaluated according to the following criteria.

[0038] • Recovery rate of the target metals (cobalt (Co) and nickel (Ni)); 70% or more is rated as "0", 50% or more but less than 70% is rated as "△", and less than 50% is rated as "×".

[0039] • Recovery rate of metals other than the target metals (iron (Fe), aluminum (Al), and manganese (Mn)); below 10% is rated as "0", above 10% but below 30% is rated as "△", and above 30% is rated as "×". Furthermore, for metals other than the target metals, a higher recovery rate means they will remain in the filtrate along with the target metals and be recovered, making selective recovery of the target metals impossible, which is undesirable.

[0040] • Recovery rate of other metals (lithium (Li) and copper (Cu)); 35% or more is rated as “0”, 10% or more but less than 35% is rated as “△”, and less than 10% is rated as “×”.

[0041] [Table 2] Comparative Examples 1-3 are conventionally known treatment methods using organic or inorganic acids. It is evident that not only cobalt and nickel, the metals targeted for recovery, but also aluminum, iron, and manganese, metals not targeted for recovery, are simultaneously recovered, making selective recovery of cobalt and nickel impossible. On the other hand, Examples 1-9 are the lithium-ion battery waste treatment methods of the present invention. It is evident that the recovery rates of aluminum, iron, and manganese, metals not targeted for recovery, can be reduced, while selective recovery of cobalt and nickel, the metals targeted for recovery, can be achieved simultaneously. In particular, Examples 3, 4, 6, and 8, which use chelate-type amine compounds having two or more amino groups as compound (1) and monocarboxylic acid-based organic or inorganic acids as compound (2), exhibit particularly excellent recovery rates of desirable valuable metals such as nickel and cobalt.

[0042] [Table 3] Examples 10-19 illustrate the lithium-ion battery waste treatment method of the present invention, which demonstrates the ability to reduce the recovery rates of metals other than those targeted for recycling, such as aluminum, iron, and manganese, while selectively recovering cobalt and nickel, which are the target metals for recycling. Particularly in Examples 10 (using ammonium chloride and ammonia), 12 (using 2-piperazine hydrochloride monohydrate and ammonia), 13 (using cysteine ​​hydrochloride and ammonia), 15 (using ethylenediamine dihydrochloride and ammonia), and 18 (using L-lysine hydrochloride and ammonia), the recovery rates of desired valuable metals such as nickel and cobalt exhibit particularly excellent results.

Claims

1. A method for treating lithium-ion battery waste, comprising wet-processing the lithium-ion battery waste to obtain a leachate containing at least dissolved cobalt and nickel, characterized in that... The following steps are required: Wet treatment steps: Add at least one compound selected from the group consisting of ammonia and its salts, and amine compounds and their salts to the lithium-ion battery waste and mix them to obtain the leaching solution containing at least the cobalt and the nickel dissolved in it. and Solid-liquid separation step: After the wet treatment step, at least a portion of the metal that is not soluble in the leaching solution is removed by solid-liquid separation.

2. The method for treating lithium-ion battery waste as described in claim 1, wherein, In this wet processing step, in addition to the compound (1), an acid is added and mixed.

3. The method for treating lithium-ion battery waste as described in claim 2, wherein, The acid is selected from at least one compound from the group consisting of monocarboxylic acid organic acids and inorganic acids (2).

4. The method for treating lithium-ion battery waste as described in claim 1, wherein, The compound (1) is selected from at least one compound from the group consisting of amine compounds having an amino group and their salts.

5. The method for treating lithium-ion battery waste as described in claim 1, wherein, The compound (1) is selected from at least one compound in the group consisting of chelate amine compounds having two or more amino groups and their salts.

6. The method for treating lithium-ion battery waste as described in claim 1, wherein, The lithium-ion battery waste contains aluminum, and at least a portion of the aluminum is removed during the solid-liquid separation step.

7. The method for treating lithium-ion battery waste as described in claim 1, wherein, The lithium-ion battery waste contains iron, and at least a portion of the iron is removed during the solid-liquid separation step.

8. The method for treating lithium-ion battery waste as described in claim 1, wherein, The lithium-ion battery waste contains manganese, and at least a portion of the manganese is removed during the solid-liquid separation step.

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