JP5151072B2 - Method for recovering metal constituting electrode from lithium battery - Google Patents

Description

  The present invention relates to a method for recovering an electrode constituent metal of a lithium battery.

  In recent years, recycling of industrial products has been demanded on a global scale from the viewpoints of global environmental conservation, effective use of resources, etc., and there is a similar demand for lithium batteries. In particular, since lithium batteries use transition metals such as nickel and cobalt for the positive electrode, it is economically valuable to recover valuable transition metals such as nickel and cobalt from used lithium batteries. A collection method has been proposed.

  For example, in Patent Document 1, a positive electrode active material for a lithium ion secondary battery or an active material waste material generated in the manufacturing process of a positive electrode active material is dissolved in at least one acid of hydrochloric acid, sulfuric acid and aqua regia to dissolve a metal. There has been proposed a method for recovering an electrode constituent metal comprising a dissolving step for adjusting the liquid.

  In addition, for example, in Patent Document 2, lithium ion battery waste material is leached with an inorganic acid, and oxalic acid is added to a purified solution obtained by removing impurities to adjust the pH to 6 to 10 to obtain cobalt hydroxide or A method of recovering a cobalt compound from a lithium ion secondary battery waste material that acquires cobalt carbonate as a precipitate has been proposed.

  On the other hand, although it is not a lithium battery, for example, Patent Document 3 discloses waste nickel-hydrogen secondary in which alkali sulfide or hydrogen sulfide is added to a nickel and cobalt solution to remove copper and cadmium in the solution as sulfides. A method for recovering valuable materials from batteries has been proposed.

JP 2002-198103 A Japanese Patent Laid-Open No. 11-6020 JP-A-9-82371

  However, in the methods of Patent Documents 1 to 3, transition metals such as nickel and cobalt are recovered with high yield and high purity from the presence of many impurity metals (for example, Fe, Al, Cu, etc.) and carbon. There is room for improvement.

  The present invention provides a method for recovering an electrode constituent metal from a lithium battery, which can recover a transition metal from the lithium battery with high yield and high purity.

  The present invention is a method for recovering an electrode constituent metal from a lithium battery comprising a positive electrode containing one or more transition metals and carbon, wherein the transition metal and impurities are mixed from the positive electrode by mixing the positive electrode and oxalic acid. A material separation step for separating the material A containing metal and carbon, and the material A and aqua regia are mixed and heated to elute the transition metal and the impurity metal, and the transition A carbon separation step for separating the material to be treated B containing the metal and the impurity metal and the carbon, and the material B to be treated and an acidic solution are mixed, and a sulfide is introduced to convert the transition metal as a sulfide. And an impurity metal separation step of separating the transition metal and the impurity metal by elution.

  Moreover, the electrode constituent metal recovery method from the lithium battery preferably includes an alkali mixing step of mixing the material to be processed B and an alkaline solution after the carbon separation step.

  Moreover, the electrode constituent metal recovery method from the lithium battery preferably includes a strong alkali mixing step of further mixing the material to be treated B and an alkaline solution stronger than the alkaline solution after the alkali mixing step.

  Moreover, the electrode constituent metal recovery method from the lithium battery preferably includes a strong alkali mixing step of mixing the transition metal and an alkaline solution stronger than the alkaline solution after the impurity metal separation step.

  Moreover, the electrode constituent metal recovery method from the lithium battery preferably includes an ashing treatment step of heating and ashing the material A to be treated after the material separation step.

  In the method for recovering an electrode constituent metal from a lithium battery according to the present invention, a transition metal can be recovered from the lithium battery with high yield and high purity.

  Embodiments of the present invention will be described below.

  An electrode constituent metal recovery method for a lithium secondary battery according to an embodiment of the present invention includes: (a) a process for separating a material to be treated A containing a transition metal, an impurity metal, and carbon from a positive electrode by mixing the positive electrode and oxalic acid. A treatment material separation step; and (b) the treatment material A and aqua regia are mixed and heated to elute the transition metal and the impurity metal, and the treatment material B and the carbon containing the transition metal and the impurity metal. A carbon separation step of separating, (c) an alkali mixing step of mixing the material to be treated B and an alkaline solution, and (d) mixing the material to be treated B and an acidic solution, and introducing a sulfiding agent as a sulfide. An impurity metal separation step of eluting the transition metal to separate the transition metal and the impurity metal; and (e) a strong alkali mixing step of mixing the transition metal and an alkaline solution stronger than the alkaline solution used in the alkali mixing step; , Including It is intended.

<(A) Material separation process>
By mixing the positive electrode and oxalic acid, the material A to be treated containing transition metal, impurity metal, and carbon can be separated from the positive electrode. The transition metal and impurity metal separated from the positive electrode are precipitated as carbonates or oxalates, and carbon is insoluble in oxalic acid, and therefore remains as a precipitate as it is.

  A lithium battery has constituent materials such as a positive electrode, a negative electrode, a separator, an electrolytic solution, and a battery case. Therefore, when mixing the positive electrode and oxalic acid, it is preferable that the constituent materials other than the positive electrode are removed as much as possible. In order to take out the positive electrode from the lithium battery, generally a used lithium battery is subjected to a vacuum heat treatment (heating temperature: 300 ° C. to 800 ° C.), and the electrolyte and organic solvent constituting the electrolytic solution are decomposed or volatilized. The electrode (positive electrode and negative electrode) is taken out and the positive electrode is separated from the electrode.

In general, the positive electrode is obtained by adhering a positive electrode material and carbon as a conductive material to an aluminum foil as a positive electrode current collector. The positive electrode material contains one or more transition metals and is a composite oxide of the transition metal and lithium. The positive electrode material as such a complex oxide can be represented by, for example, the general formula LiA _1-X B _X O ₂ . A and B represent transition metals and are metal elements selected from, for example, Ni, Co, Mn, Fe, and Nb. In the present embodiment, A and B are preferably Ni (nickel) or Co (cobalt). Note that X = 0 to 1.

  An impurity metal refers to a metal that is not intended to be recovered from a lithium battery. For example, when the purpose is to collect at least one of Ni and Co as a transition metal in the positive electrode material, Cu (for example, a negative electrode current collector), Fe (for example, a battery case) mixed when the positive electrode is separated from a lithium battery, Al (for example, battery case, positive electrode current collector), Li originally contained in the positive electrode material, and the like are impurity metals. When the purpose is to recover only Ni as a transition metal in the positive electrode material, the Co becomes an impurity metal.

  Carbon is one that is mixed when the positive electrode is separated from the lithium battery, or one that is originally contained in the positive electrode material. Examples thereof include graphite carbon as a negative electrode material, carbon black as a conductive material, and the like.

  The concentration of oxalic acid, addition time, temperature, etc. are not particularly limited.

  It is preferable that after the said to-be-processed material isolation | separation process, the to-be-processed material A is heated and it incinerates and incinerates.

  The ashing treatment is preferably performed by heating the material A to be ashed for 30 to 100 minutes in the range of 600 ° C to 800 ° C. As a result, most of the carbon can be completely decomposed, so that the carbon can be easily separated from the material to be treated A in the subsequent carbon separation step.

<(B) Carbon separation step>
By mixing and heating the material to be treated A and aqua regia, the transition metal and the impurity metal can be ionized and eluted, so the material to be treated B containing the transition metal and the impurity metal and carbon (graphite carbon and carbon black) ) Can be separated. Conventionally, most of the impurity metals are removed from the material A to be treated with hydrochloric acid after the process of separating the material to be treated, and the transition metal is dissolved with sulfuric acid to separate the carbon. However, dissolution by sulfuric acid (or dissolution by heating) causes dehydrogenation abstraction reaction with respect to carbon, and it is difficult to completely decompose carbon. Further, when heat treatment is performed in a state where the sulfuric acid concentration is increased and the viscosity is high, the carbon particle surface is gradually refined by dissolution (decomposition) or physical impact (due to boiling of the solution by heating). For this reason, it becomes difficult to separate the carbon with a filter paper or a filter, and carbon is mixed as an impurity in the filtrate of the eluted transition metal or the like. However, since aqua regia has a lower boiling point and viscosity than sulfuric acid and does not cause dehydrogenation of carbon, it does not cause dissolution or refinement of carbon particles. Can be separated.

  The aqua regia is not particularly limited as long as it is a mixed solution of hydrochloric acid and nitric acid. Common aqua regia with a volumetric mixture ratio of hydrochloric acid and nitric acid of 3: 1 may be used, or the volumetric mixture ratio of hydrochloric acid and nitric acid is 1 to 1.5: 2.5 to 3.0. Aqua regia can also be used. As described above, when the positive electrode is taken out from the lithium battery, the lithium battery is heated in a vacuum heating furnace. By this heating (for example, 400 ° C.), a part of the positive electrode material is hardly soluble carbide or a compound having a complicated composition. Form. When conventional sulfuric acid is used, the above-mentioned hardly soluble carbides and complex compounds cannot be dissolved, and hardly soluble salts are produced. Therefore, transition metals contained in hardly soluble salts are treated together with carbon. Separated from material B. However, these can be suitably dissolved in aqua regia or reverse aqua regia.

  The heat treatment with aqua regia is not particularly limited, but for example, it is preferable to heat the material to be treated A until almost no bubbles are generated in the range of 50 ° C to 100 ° C. The bubbles generated from the material A to be processed are those generated from the carbonate of the transition metal and the impurity metal precipitated by the oxalic acid, so that the transition metal and the impurity metal are ionized and eluted by the disappearance of the bubble. Show.

<(C) Alkali mixing step>
It is preferable to include a step of mixing the material to be treated B (including a transition metal and an impurity metal) and an alkaline solution. The material B to be processed contains a transition metal and an impurity metal. For example, when the impurity metal contains iron, copper, aluminum, etc., an impurity containing iron, copper, aluminum can be precipitated as a hydroxide by adding an alkaline solution, and the transition metal can be stabilized as an ammine complex. Can be eluted. The alkali mixing step can particularly effectively precipitate iron as a hydroxide.

The addition of the alkaline solution is preferably performed until the pH of the material to be treated B from which the carbon has been separated becomes weakly acidic at about 5.0 to 6.0. When the pH is lower than 5.0, hydroxide precipitates may not be generated. When the pH is higher than 6.0, hydroxide precipitates may be deposited and adsorbed. The concentration of the alkaline solution is preferably in the range of 5 to 15% by weight. If it is higher than 15% by weight, a part of the transition metal may be precipitated as a hydroxide. Examples of the alkaline solution include, but are not limited to, a 10 wt% NH ₄ OH aqueous solution, ammonium chloride dissolved in ammonium chloride, and the like.

<(D) Impurity metal separation step>
By mixing the material to be processed B and the acidic solution and introducing a sulfiding agent, the transition metal can be eluted from the material to be processed B and the impurity metal can be separated.

  The acidic solution is not particularly limited, and for example, sulfuric acid, hydrochloric acid, nitric acid and the like can be used. Preferably, 1N to 4N dilute sulfuric acid is used. Although it is possible to use sulfuric acid with a high concentration such as concentrated sulfuric acid, transition metal (sulfide of transition metal) is likely to precipitate, and it is difficult to separate it from impurity metals, resulting in a decrease in transition metal recovery rate. There is. Further, the addition of the acidic solution is preferably performed (adjusted) until the pH of the material to be treated B becomes 1.5 to 3.0. If the pH is higher than 3.0, it may be difficult to elute the transition metal and separate the impurity metal even if a sulfiding agent is introduced.

  The sulfiding agent is not particularly limited as long as it can elute transition metals as sulfides. For example, it is generated from an acidic solution such as hydrogen sulfide gas or alkali sulfide (sodium sulfide, potassium sulfide, etc.). Hydrogen sulfide gas or the like can be used. Preferably, hydrogen sulfide gas is used. By introducing the sulfurized gas, the impurity metal can be precipitated as a sulfide and the transition metal can be separated as a sulfuric acid solution (filtrate). In particular, copper can be effectively precipitated as copper sulfide.

  The introduction time, gas concentration, and gas flow rate of the sulfide gas are not particularly limited, but the introduction time of the sulfide gas is 5 minutes to 30 minutes, the gas concentration is 5 to 20% (in Air), and the gas flow rate is 2 to 2 minutes. The range is preferably 8 L / min.

  Conventionally, in order to separate the impurity metal, the impurity metal is precipitated as a hydroxide by adding an aqueous sodium hydroxide solution. In this case, depending on the adjustment of reaction temperature, pH setting, etc., it becomes difficult to precipitate the impurity metal as a hydroxide (because the solubility of the impurity metal hydroxide increases), and it is difficult to separate the impurity metal. On the other hand, it tends to be accompanied by the formation of transition metal hydroxide precipitates. In this embodiment, by having the alkali mixing step (c) and the impurity metal separation step (d), particularly the impurity metal separation step, it is possible to prevent the transition metal from being precipitated as a hydroxide together with the impurity metal. In addition, only the impurity metal can be easily precipitated as a hydroxide.

<(E) Strong alkali mixing step>
It is preferable to include a step of mixing the transition metal with a stronger alkaline solution than the alkaline solution (for example, aqueous ammonia solution) used in the step (c). Thereby, the transition metal can be precipitated as a hydroxide. Moreover, when the impurity metal which cannot be isolate | separated by said (d) impurity metal isolation | separation process exists, it can be eluted as a solution of a hydroxide. For example, in particular, Li, Al, etc. can be effectively eluted as a hydroxide solution.

  The mixing with the strongly alkaline alkaline solution is preferably performed until the pH of the transition metal is about 9.5-12. If the pH is lower than 9.5, it may be difficult to precipitate the transition metal as a hydroxide. If the pH is higher than 12, the transition metal hydroxide precipitates together with the impurity metal as a hydroxide. There is.

  The strong alkaline solution is not particularly limited as long as it has stronger alkalinity than the alkaline solution used in the alkali mixing step. Examples of the strong alkaline alkaline solution include, but are not limited to, an aqueous solution of sodium hydroxide, potassium hydroxide and the like whose concentration is in the range of 10 to 20% by weight.

FIG. 1 is a flowchart showing an example of a method for recovering an electrode constituent metal from a lithium battery according to the present embodiment. Here, as the lithium battery, a used lithium ion secondary battery using a composite oxide of LiNi _1-X Co _X O ₂ as a positive electrode material is taken as an example. Note that X = 0 to 1.

  In step S10, a used lithium ion secondary battery is prepared, and in step S12, the positive electrode is taken out (separated) from the lithium ion secondary battery. In step S14, the positive electrode is added to the oxalic acid solution, and the material A to be treated containing transition metal, impurity metal, and carbon is separated from the positive electrode. In step S16, the oxalic acid-added solution is separated by filtration (S14, S16 :( a) Material separation step), the separated material A (residue) and the filtrate are obtained. Here, for example, Cu (mixed from the negative electrode current collector), Al (mixed from the positive electrode current collector), Fe (mixed into the used lithium ion from the exterior of the battery), Li (mixed from the positive electrode material) ) Will be described below. The filtrate contains, for example, Al (aluminum current collector) in the positive electrode, Li (Li in the positive electrode material, Li in the electrolytic solution, etc.), Ni (Ni which is part of the transition metal to be recovered), and the like. . In step S22, the material A to be treated is washed with water, and impurities that have not been partially removed as a filtrate, such as lithium, are removed as a filtrate. In step S26, the transition metal (Ni, Co), the impurity metal (Cu, Fe, Al, (partially remaining Li), etc.), and the carbon are incinerated by heating and ashing to decompose the carbon. . In step S28, aqua regia is added to the ashed transition metal, impurity metal, and carbon to elute the transition metal and impurity metal. In step S30, the aqua regia addition solution is separated by filtration (S28, S30: ( b) Carbon separation step), to-be-treated material B containing the eluted transition metal and impurity metal is used as a filtrate, and carbon is obtained as a residue. In step S36, an alkaline solution, for example, an aqueous ammonia solution is added to the filtrate to precipitate impurity metals (Fe (partial Cu and Al), etc.) as hydroxides. In step S38, the aqueous ammonia solution is separated by filtration. (S36, S38: (c) alkali mixing step), transition metal (ammine complex) and impurity metal (Cu, Al, (Li), etc.) are used as filtrate, and impurity metal (Fe (partial Al and Cu)) Etc.) as a residue. In step S44, the pH of the filtrate is adjusted with an acidic solution, for example, 4N dilute sulfuric acid. In step S46, a sulfide gas, such as hydrogen sulfide gas, is introduced into the filtrate whose pH has been adjusted, and impurity metals (Cu, etc.) are introduced. In step S48, the solution after introduction of hydrogen sulfide gas is separated by filtration (S44 to S48: (e) impurity metal separation step), and transition metals and impurity metals (Al, (Li), etc.) are filtered. As a liquid, a sulfide of an impurity metal (Cu or the like) is obtained as a residue. In step S54, an alkaline solution stronger than the alkaline aqueous solution used in step S36, such as a sodium hydroxide aqueous solution, is added to the filtrate to precipitate the transition metal as a hydroxide. In step S56, a sodium hydroxide added solution is added. Are separated by filtration (S54, S56: strong alkali mixing step), and the transition metal hydroxide is recovered as a residue using impurity metals (Al, Li, etc.) as a filtrate.

  As described above, in the electrode constituent metal recovery method from the lithium battery according to the embodiment of the present invention, a high-purity transition metal can be recovered with a high recovery rate.

  Next, an electrode constituent metal recovery method from a lithium battery according to another embodiment of the present invention will be described.

  In the method for recovering an electrode constituent metal from a lithium battery according to another embodiment of the present invention, (1) a positive electrode and oxalic acid are mixed to separate a material A to be treated containing transition metal, impurity metal and carbon from the positive electrode. Processed material separation step; (2) Processed material A and aqua regia are mixed and heated to elute the transition metal and impurity metal, and process material B containing the transition metal and impurity metal is mixed with carbon. (3) an alkali mixing step for mixing the material B to be treated and an alkaline solution, and (4) an alkaline solution that is stronger than the alkaline solution used in the material B and the alkali mixing step. (5) Mixing the material B to be treated and an acidic solution, introducing a sulfurizing agent to elute the transition metal as a sulfide, and separating the transition metal from the impurity metal Separation process and It is intended to include.

  The steps (1) to (3) are the same as the steps (a) to (c) described above.

  The strong alkali mixing step (4) is the same as the strong alkali mixing step (e) described above, but a strong alkaline alkaline solution is mixed before the impurity metal separation step (5). Thereby, impurity metals (for example, Al, Li) that are easily eluted as a hydroxide solution in a strong alkali state can be eluted first. On the other hand, transition metals can be obtained as hydroxide precipitates.

  The step (5) is the same as the step (d) described above. However, mixing with the acidic solution is performed not only for pH adjustment but also for dissolving the transition metal obtained as the hydroxide precipitate. Moreover, since the transition metal finally obtained by introduction | transduction of a sulfurization agent is obtained as a sulfide solution, after that, a sulfide solution may be concentrated.

FIG. 2 is a flow chart showing an example of a method for recovering an electrode constituent metal from a lithium battery according to another embodiment. Here, the lithium battery is exemplified by a lithium ion secondary battery using a composite oxide of LiNi _1-X Co _X O ₂ as a positive electrode material. Note that X = 0 to 1.

  In step S100, a used lithium ion secondary battery is prepared, and in step S102, the positive electrode is taken out (separated) from the lithium ion secondary battery. In step S104, the positive electrode is added to the oxalic acid solution, and the material A to be treated containing transition metal, impurity metal, and carbon is separated from the positive electrode. In step S106, the oxalic acid-added solution is separated by filtration (S104, S106 :( 1) To-be-treated material separation step), the separated to-be-treated material A (residue) and the filtrate are obtained. Here, the following description will be made assuming that the impurity metal is the same as above (Cu, Al, Fe, Li). The filtrate is the same as described above. In step S112, the material A to be treated is washed with water to remove impurities that could not be partially removed as a filtrate, such as lithium. In step S116, aqua regia is added to transition metals (Ni, Co), impurity metals (Cu, Fe, Al, (partially remaining Li)), and carbon, and the transition metals and impurity metals are eluted. Moreover, before adding aqua regia, an ashing treatment may be performed in the same manner as in step S26, but it is omitted in other embodiments of the present invention. In step S118, the aqua regia added solution is separated by filtration (S116, S118: (2) carbon separation step), and the material B to be treated containing the eluted transition metal and impurity metal is used as a filtrate to obtain carbon as a residue. In step S124, an alkaline solution, for example, an aqueous ammonia solution is added to the filtrate to precipitate impurity metals (Fe, (some Cu and Al), etc.) as hydroxides. In step S126, the aqueous ammonia solution is filtered. Separating (S124, S126: (3) alkali mixing step), using transition metal (ammine complex) and impurity metal (Cu, Al, (Li), etc.) as filtrate, impurity metal (Fe (some Al and Cu) ) Etc.) as a residue. In step S132, an alkaline solution that is stronger than the alkaline solution used in step S124, such as an aqueous sodium hydroxide solution, is added to the filtrate to precipitate transition metals and impurity metals (such as Cu) as hydroxides, and step S134. Then, the sodium hydroxide added solution is separated by filtration (S132, S134: (4) strong alkali mixing step), and a transition metal and impurity metal (Cu) are obtained using a hydroxide solution of impurity metals (Al, Li, etc.) as a filtrate. Etc.) as a residue. In S140, an acidic solution, for example, 4N dilute sulfuric acid is added to dissolve the residue, and the pH is adjusted. In step S142, a sulfide gas, for example, hydrogen sulfide gas, is introduced into the solution in which the pH-adjusted residue is dissolved. In step S144, the solution after introducing the hydrogen sulfide gas is separated by filtration (S140 to S144: (5) impurity metal separation step), and the transition metal is used as a filtrate. Then, a sulfide of an impurity metal (Cu or the like) is obtained as a residue. In step 150, the filtrate is concentrated and the transition metal is recovered as a sulfide.

  As described above, even in the electrode constituent metal recovery method from the lithium battery according to another embodiment of the present invention, a high-purity transition metal can be recovered at a high recovery rate.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to a following example.

<Example 1: Method for recovering electrode-constituting metal from lithium battery>
Ten used lithium ion secondary batteries were prepared (S10), and the positive electrode was separated (S12). Next, the positive electrode was immersed in a 5% by weight oxalic acid bath (S14). Thereby, the transition metal, impurity metal, and carbon were separated from the positive electrode (S16), and about 100 g of carbonate and carbon of the transition metal and impurity metal were recovered. This was treated material A, and about 100 g of treated material A was incinerated (S26). Ashing treatment was performed at 750 ° C. for 60 minutes. Next, 200 ml of reverse aqua regia (hydrochloric acid 1 and nitric acid 3) was gradually added to the treated material A after ashing, and heated and dissolved at 100 ° C. (S28), and concentrated to 80 ml (in this case) It is confirmed whether or not bubbles are generated from the material A to be processed, and if bubbles are generated, they are further heated). After allowing the concentrate to cool, about 200 ml of distilled water was added, shaken and mixed, filtered into a resin container (S30), and the filter paper was washed with about 50 ml of distilled water 2-3 times. The filter paper is Advantech No. 5A, Φ400 mm was used. The same filter paper was used for all subsequent filtration separations. Next, an aqueous ammonia solution having a concentration of 10% by weight is added to the filtrate, and the filtrate is adjusted to pH 5.0 ± 2 using a pH meter and a stirrer (S36), and a part of the impurity metal is hydroxide. And filtered and separated (S38), and the filter paper was washed with about 50 ml of distilled water 2 to 3 times to recover the residue. Next, 4N dilute sulfuric acid is added to the filtrate to adjust to pH 2.0 ± 0.1 (S44), and hydrogen sulfide gas with a gas concentration of 15% is introduced at 2-3 L / min for 15 minutes. (S46), a part of the impurity metal was precipitated as sulfide, filtered and separated (S48), and the residue on the filter paper was washed with about 50 ml of distilled water 2 to 3 times. Next, a sodium hydroxide aqueous solution having a concentration of 10% by weight as an alkaline solution stronger than an aqueous ammonia solution is added to the filtrate (S54), and transition metals (Ni, Co) are precipitated as hydroxides and separated by filtration ( S56), the filter paper was washed 2 to 3 times with 50 ml of distilled water to recover the residue and filtrate.

<Examples 2 and 3: Electrode constituent metal recovery method from lithium battery>
In Example 2 above, in S36, an aqueous ammonia solution having a concentration of 10% by weight was added to the filtrate so that the filtrate had a pH of 5.5 ± 0.2 (S36). The same method as in Example 1 was used. Furthermore, in Example 3, the aqueous ammonia solution having a concentration of 10% by weight was added to the filtrate in S36, and the filtrate was adjusted to pH 6.0 ± 0.2 (S36). The same method as in Example 1 was used.

  In Examples 1 to 3, a residue (I shown in FIG. 1) obtained after addition of an aqueous ammonia solution (S36), a residue obtained after introduction of hydrogen sulfide gas (S46) (II shown in FIG. 1), an aqueous sodium hydroxide solution The results of the ICP emission spectroscopic analysis (ICPS2000 type manufactured by Shimadzu Corporation) of the filtrate (III shown in FIG. 1) obtained after the addition (S54) and the finally recovered transition metal residue (IV shown in FIG. 1) are shown. It shows in Tables 1-3.

  As can be seen from Tables 1 to 3, the impurity metal could be effectively removed by adding an aqueous ammonia solution, but the amount of Ni residue also increased as the pH increased (not shown in the table, although not shown in the table). The residue also increased). Further, by introducing hydrogen sulfide gas, an impurity metal (for example, Cu) that is difficult to remove by adding an aqueous ammonia solution could be removed. Further, by adding an aqueous sodium hydroxide solution, trace amounts of impurity metals (for example, Al or Li not shown in the table, etc.) remaining in the filtrate could be removed. The amount also increased (not shown in the table, but the amount of Co residue also increased). From the above, Examples 1 and 2 in which an aqueous ammonia solution was added to adjust the pH to 5.0 to 5.5 were finally obtained because the amount of Ni and Co residues in each step could be suppressed. The recovery rate of the transition metals (Ni and Co) obtained was over 95%. On the other hand, in Example 3 in which the pH was adjusted to 6.0, the amount of Ni and Co residues in each step increased, and the recovery rate of the transition metal (Ni and Co) finally obtained is different from that in other examples. Although it is inferior, the impurity metals present in the final recovery were less than those of the other examples, and high-purity transition metals (Ni and Co) could be recovered. As a result, considering both the recovery rate and the purity, Example 2 in which the pH was adjusted to 5.5 by adding an aqueous ammonia solution is the optimum condition. The recovery rate (yield) was determined by (actual yield mg / theoretical yield mg) × 100.

<Example 4: Method for recovering metal constituting electrode from lithium battery>
Ten used lithium ion secondary batteries were prepared (S100), and the positive electrode was separated (S102). Next, the positive electrode was immersed in a 5% by weight oxalic acid bath (S104). Thereby, the transition metal, impurity metal, and carbon were separated from the positive electrode (S106), and about 100 g of carbonate and carbon of the transition metal and impurity metal were recovered. This is treated material A, and 400 ml of aqua regia (hydrochloric acid 3 and nitric acid 1) is gradually added and dissolved by heating at 100 ° C. (S 116), and concentrated to 80 ml (from the material A to be treated). Check if bubbles are generated. If bubbles are generated, heat further.) After allowing the concentrate to cool, about 200 ml of distilled water was added and shaken and filtered into a resinous container (S118), and the residue after filtration was washed 2 to 3 times with about 50 ml of distilled water on the filter paper. The filter paper is Advantech No. 5A, Φ400 mm was used. The same filter paper was used for all subsequent filtration separations. Next, an aqueous ammonia solution having a concentration of 10% by weight is added to the filtrate, and the filtrate is adjusted to pH 6.0 ± 0.1 using a pH meter and a stirrer (S124), and a part of the impurity metal is hydroxylated. The product was precipitated as a product, separated by filtration (S126), and the residue on the filter paper was washed 2 to 3 times with about 50 ml of distilled water. Next, an aqueous solution of sodium hydroxide having a concentration of 10% by weight as an alkaline solution stronger than an aqueous ammonia solution is added to the filtrate, and the pH is adjusted to 11.5 ± 0.2 (S132), and the transition metal is precipitated as a hydroxide. Then, a part of the impurity metal is eluted and separated by filtration (S134), and the filter paper is washed 2 to 3 times with about 50 ml of a sodium hydroxide aqueous solution having a pH of 10 to 11 and subsequently washed with about 50 ml of distilled water 2 to 3 times. The filtrate was collected. Next, after the precipitate was transferred to a resin beaker containing about 400 ml of distilled water, 4N dilute sulfuric acid was gradually added to adjust the pH to 1.5 to 2.5 while dissolving the precipitate. A hydrogen sulfide gas having a gas concentration of 10% was introduced into the adjusted solution (S140) at a rate of 2 to 3 L / min for 15 minutes (S142), and a part of the impurity metal was precipitated as a sulfide. Thereafter, air was introduced at 2-3 L / min for 30 minutes, the solution was separated by filtration (S144), and the residue on the filter paper was washed once or twice with about 50 ml of distilled water. Next, the filtrate was concentrated to about 100 ml (S150), and transition metals (Ni, Co) were recovered.

  In Example 4, the residue (VI shown in FIG. 2) obtained after the addition of the aqueous ammonia solution (S124), the filtrate (VII shown in FIG. 2) obtained after the addition of the aqueous sodium hydroxide solution (S132), introduction of hydrogen sulfide gas ( S142) Atomic absorption analysis of the residue (VIII shown in FIG. 2) and the finally recovered transition metal (Ni, Co) concentrate (IX shown in FIG. 2) (AA6700F type, manufactured by Shimadzu Corp.) Table 4 shows the results and the results of the residue after addition of aqua regia (V shown in FIG. 2). The amount of residue after the addition of aqua regia is the loss on ignition determined by dry ashing the residue.

  From the method of Example 4, almost all the carbon contained in the sample could be removed by adding aqua regia. Further, in Example 4, the addition of the aqueous sodium hydroxide solution was performed after the addition of the aqueous ammonia solution, but the impurity metals could be effectively removed as in Examples 1 to 3. Furthermore, by introducing hydrogen sulfide gas, impurity metals that could not be separated in the above could be separated. Thereby, the recovery rate of the finally obtained transition metals (Ni and Co) exceeded 90%.

<Effects of adding aqua regia>
(Example 5)
Five used lithium ion secondary batteries were prepared (S100), and the positive electrode was separated (S102). Next, the positive electrode was immersed in a 5% by weight oxalic acid bath (S104). Thereby, the transition metal, impurity metal, and carbon were separated from the positive electrode (S106), and about 50 g of carbonate and carbon of the transition metal and impurity metal were recovered. This is treated material A, and 300 ml of aqua regia (3 dissolved hydrochloric acid and 1 dissolved nitric acid) is gradually added and dissolved by heating at 100 ° C. (S 116), and concentrated to 80 ml (at this time, from treated material A Check if bubbles are generated. If bubbles are generated, heat further.) After allowing the concentrate to cool, about 200 ml of distilled water was added, shaken and mixed, filtered into a resinous container (S118), and washed with about 50 ml of distilled water 2-3 times to recover the residue (V shown in FIG. 2). . This was designated as Example 5.

  Comparative Examples 1, 2 and 3 were prepared by adding 300 ml of hydrochloric acid, 300 ml of nitric acid and 300 ml of sulfuric acid instead of adding 300 ml of aqua regia in Example 5 above.

  Table 5 shows the results obtained by the residue obtained by Example 5 and Comparative Examples 1 to 3 by fluorescent X-ray analysis (XRF-1700 type, manufactured by Shimadzu Corporation).

  From the results of Table 5, it was found that Example 5 to which aqua regia was added had less residue than Comparative Examples 1, 2, and 3 to which other acids were added. Since the smaller the amount of the residue, the more acid other than carbon in the material A to be treated was ionized and eluted by the acid to be added, so that Example 5 to which aqua regia was added was more final than Comparative Examples 1 to 3. The yield of the transition metal obtained can be increased.

<Effects of addition amount of aqua regia and reverse aqua regia>
Five used lithium ion secondary batteries were prepared (S10), and the positive electrode was separated (S12). Next, the positive electrode was immersed in a 5% by weight oxalic acid bath (S14). Thereby, the transition metal, impurity metal, and carbon were separated from the positive electrode (S16), and about 50 g of carbonate and carbon of the transition metal and impurity metal were recovered. This was treated material A, and about 50 g of treated material A was incinerated (S26). Ashing treatment was performed at 750 ° C. for 60 minutes. Next, 100 ml of aqua regia (hydrochloric acid 3 and nitric acid 1) is gradually added to the treated material A after ashing, heated and dissolved at 100 ° C. (S28), and concentrated to 80 ml (at this time, It is confirmed whether bubbles are generated from the treatment material A, and if bubbles are generated, they are further heated). After allowing the concentrate to cool, about 200 ml of distilled water is added and shaken and mixed, filtered into a resin container (S30), and the residue on the filter paper is washed 2 to 3 times with about 50 ml of distilled water (see FIG. 1). X). This was designated Example 6. In Examples 7, 8 and 9, aqua regia was gradually added to 140 ml, 180 ml and 220 ml in place of 100 ml of aqua regia (3 hydrochloric acid and 1 nitric acid) of Example 6. Other Examples 6 and the same method. Further, Examples 10, 11 and 12 were prepared by gradually adding 100 ml, 180 ml and 220 ml of reverse aqua regia (hydrochloric acid 1 and nitric acid 3) instead of 100 ml of aqua regia of Example 6. In the same manner as in Example 6. Table 6 shows the results of the precipitates obtained in Examples 6 to 12 obtained by fluorescence X analysis (XRF-1700 type, manufactured by Shimadzu Corporation).

  Although the amount of residue was generally small because of the ashing treatment, in Examples 9 and 12 to which 220 ml of aqua regia or reverse aqua regia was added, the amount of residue could be reduced to 1% or less. The lower the amount of residue, the more ionized and eluted than carbon in the material A to be treated. In Examples 9 and 12, the amount of Ni and Co in the residue was the lowest. Furthermore, the amount of residue can be reduced by adding reverse aqua regia rather than adding aqua regia, but Example 12 is the least amount of residue, and the amount of Ni and Co in the residue can be suppressed. I knew it was possible.

It is a flowchart which shows an example of the electrode structure metal collection | recovery method from the lithium battery which concerns on this embodiment. It is a flowchart which shows an example of the electrode structure metal collection | recovery method from the lithium battery which concerns on other embodiment.

Claims (5)

An electrode constituent metal recovery method from a lithium battery comprising a positive electrode containing one or more transition metals and carbon,
A material separation step of mixing the positive electrode and oxalic acid to separate the material A to be processed containing the transition metal, impurity metal and carbon from the positive electrode;
Carbon that separates the carbon to be treated B and the carbon to be treated by mixing the material to be treated A and aqua regia and heating to elute the transition metal and the impurity metal and the transition metal and the impurity metal. A separation process;
An impurity metal separation step of mixing the material to be treated B and an acidic solution, introducing a sulfiding agent to elute the transition metal as a sulfide and separating the transition metal and the impurity metal;
A method for recovering an electrode constituent metal from a lithium battery.   The electrode constituent metal recovery method from a lithium battery according to claim 1, further comprising an alkali mixing step of mixing the material to be treated B and an alkaline solution after the carbon separation step. Electrode constituent metal recovery method.   3. The method for recovering an electrode constituent metal from a lithium battery according to claim 2, further comprising a strong alkali mixing step of further mixing the material B to be treated and an alkaline solution stronger than the alkaline solution after the alkali mixing step. A method for recovering an electrode constituent metal from a lithium battery.   3. The method for recovering an electrode constituent metal from a lithium battery according to claim 2, further comprising a strong alkali mixing step of mixing the transition metal and an alkaline solution stronger than the alkaline solution after the impurity metal separation step. A method for recovering an electrode-constituting metal from a lithium battery. 2. The method for recovering metal constituting an electrode from a lithium battery according to claim 1, further comprising an ashing treatment step of heating and ashing the material A after the material separation step. A method for recovering an electrode constituent metal from a battery.

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