KR20210120669A - Method for recovery of manganese compounds from cathode active material of waste lithium ion battery - Google Patents

Abstract

The present invention relates to a method for recovering manganese compounds from a waste positive electrode active material. Particularly, the present invention relates to a method for isolating and recovering manganese compounds in the form of manganese sulfate, manganese carbonate and manganese oxide simply and easily with high purity by leaching nickel (Ni), cobalt (Co) and lithium (Li), except manganese, selectively from waste positive electrode active material powder containing nickel (Ni), cobalt (Co), manganese (Mn) and lithium (Li), and subjecting manganese contained in the leached residue to an acid leaching process, solvent extraction process and a heat treatment process. According to the present invention, unlike the conventional methods for recovering manganese, there is no need for isolating manganese in advance, and thus it is possible to simplify a process for recovering cobalt and nickel separately, to reduce the cost of a neutralizing agent used for recovering manganese, and thus to save the production cost advantageously. In addition, when using a solvent extraction process in order to recover manganese from the leached residue, high-purity manganese can be recovered through a process reduced by two steps as compared to conventional process, and thus the production cost of manganese can be reduced.

Description

Method for recovering manganese compounds from waste cathode active materials

The present invention relates to a method for selectively recovering high-purity manganese from a residue recovered through a leaching process of a waste cathode active material of a lithium secondary battery in a simpler and more economical way than the existing process, specifically nickel (Ni) , nickel (Ni), cobalt (Co), and lithium (Li) excluding manganese from the waste cathode active material powder containing cobalt (Co), manganese (Mn) and lithium (Li) are selectively leached and manganese It relates to a method for concentrating and recovering the residue. In addition, it includes a method for easily separating and recovering high-purity manganese compounds through additional processes such as acid leaching, solvent extraction, and heat treatment for manganese contained in the leaching residue.

As a core component of electric vehicles and power storage systems (ESS), lithium secondary batteries are rapidly increasing in demand as the supply of renewable energy without environmental pollution increases. As demand for electric vehicle batteries increases, the production of nickel (Ni)-cobalt (Co)-manganese (Mn) (NCM)-based cathode active materials for lithium ion batteries (LIBs, Lithium Ion Batteries) is on the rise. Among the metals in the nickel (Ni)-cobalt (Co)-manganese (Mn) (NCM) cathode active material for efficiency and economic reasons, the content of inexpensive nickel (Ni) or manganese (Mn) is relatively higher than that of expensive cobalt (Co) is a trend to

In addition, the ternary positive electrode active material used in the expired lithium ion battery contains expensive valuable metals such as cobalt (Co) and nickel (Ni). Recovery should come first.

Existing processes such as Korean Patent Registration No. 10-1325176 are a solvent extraction process for manganese dissolved together in a leaching solution, or potassium permanganate (KMnO ₄ ), disodium _{peroxide disulfate (Na 2} S ₂ O ₈ ), ozone (O ₃ ) It has been carried out as a process of recovering a solution in which three components of cobalt, nickel, and lithium exist through a process of adding and removing an expensive oxidizing agent such as cobalt.

For example, in the cathode active material of a waste battery containing manganese, cobalt, and nickel, an excess of acid and a reducing agent are added to dissolve all soluble substances including manganese, cobalt and nickel, and then, the expensive oxidizing agent disodium disulfate (disodium peroxide) ( Na ₂ S ₂ O ₈ ) is added to selectively precipitate and separate manganese. In this method, the reduction and oxidation processes must be sequentially performed, and since a reducing agent and an oxidizing agent are required in each process, it is not economical as well as the efficiency of the process is low. Furthermore, there are problems in that a high reaction temperature of 90° C. or higher is required, which increases energy cost, consumes an excess of reducing agent for manganese leaching, and in the case of oxidation precipitation, some cobalt is co-precipitated with manganese and is lost.

On the other hand, when manganese is recovered from a leaching solution in which cobalt, nickel, and manganese are mixed through a solvent extraction process, extraction of manganese should precede cobalt and nickel. To this end, in order to adjust the pH to an appropriate pH from which manganese can be extracted, an excess of neutralizing agent (NaOH) must be added, and a process of washing cobalt and nickel extracted together is added, so that at least 10 extraction stages are required. As a result, the manufacturing cost is higher than the selling cost of the manufactured manganese sulfate, which may result in a loss when the manganese sulfate is manufactured and sold.

Accordingly, in the present invention, manganese (Mn) is selectively recovered from waste cathode active material powder containing nickel (Ni), cobalt (Co), manganese (Mn) and lithium (Li) in a simpler and more economical way than the existing process. I've been working hard to find a way.

1: Korean Patent Registration No. 10-1325176 2: Korean Patent Registration No. 10-1623930

Accordingly, the inventors of the present invention perform primary and secondary leaching of the waste cathode active material powder with an acid solution without the use of a reducing agent, filtering the leaching solution, and sequentially performing acid leaching and solvent extraction on the remaining insoluble leaching residue under predetermined conditions. It has been found that high purity manganese compounds can be easily recovered. In addition, when primary acid leaching and secondary acid leaching of waste cathode active material powder with an acid solution without the use of a reducing agent, filtering the leaching solution, and recovering the remaining leaching residue, manganese is contained in a high concentration of 40% or more, so it can be used directly in the steelmaking or steelmaking process. Manganese can be reused as a raw material, and when it is heat treated, it was found that manganese oxide (Mn ₃ O ₄ , Mn ₂ O ₃ ) can be easily obtained through a single process, thereby completing the present invention.

Accordingly, an object of the present invention is to provide a method for recovering various types of manganese compounds from a waste cathode active material in a simpler and more economical way.

In order to achieve the above object, the present invention comprises the steps of (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; (b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; (c) dissolving a metal component including manganese by adding an aqueous acid solution and a reducing agent to the insoluble residue containing manganese; And (d) solvent extraction of the leaching solution of step (c), and selectively separating and concentrating manganese _{to recover manganese sulfate (MnSO 4} ) It provides a method for recovering a manganese compound from a waste cathode active material .

In addition, the present invention comprises the steps of (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; (b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; and (c) dissolving a metal component including manganese by adding an aqueous acid solution and a reducing agent to the insoluble residue containing manganese; and (d) adding alkali metal carbonate or alkali metal hydroxide to the leaching solution of step (c) to recover manganese carbonate (MnCO ₃ ) or manganese hydroxide (Mn(OH) ₂ ). A method for recovering manganese compounds from

In addition, the present invention comprises the steps of (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; (b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; and (c) recovering manganese oxide by heat-treating the insoluble residue containing manganese.

The method for recovering a manganese compound from a waste positive electrode active material according to the present invention is to re-dissolve manganese contained in the residue from the residue recovered through the leaching process of the ternary positive electrode active material through a wet process, or economically through heat treatment to obtain a high purity manganese compound. can be manufactured.

In addition, the present invention can omit the removal process of manganese, which acts as an impurity in the separation and recovery process of cobalt (Co) and nickel (Ni), which are valuable metals (see FIG. 1 ).

In addition, the present invention is economical because the extraction process for recovering manganese with high purity can be simplified or omitted by recovering manganese from the residue.

1 is an overall flow chart showing a method for separating and recovering valuable metals from waste cathode active material powder.
2 is a flowchart illustrating a method for recovering a manganese compound from a leaching residue of a waste cathode active material according to the present invention.
3 is a flowchart showing a method for recovering a manganese compound of high purity among the method for recovering a manganese compound according to the present invention.
4 is a graph showing the results of XRD analysis of the recovered residue.
5 is a graph showing the TG-DTA analysis result of the raw material of the waste cathode active material.
6 is a graph showing the XRD analysis results of the recovered manganese carbonate (MnCO _{3 ).}
7 is a graph showing the results of XRD analysis after heat-treating the recovered residue at 750°C.

Hereinafter, the present invention will be described in more detail as one embodiment as follows.

The inventors of the present invention perform primary and secondary leaching of the waste cathode active material powder with an aqueous acid solution without the use of a reducing agent, and perform acid leaching, solvent extraction, heat treatment, etc. on the insoluble leaching residue remaining after filtering the leaching solution under predetermined conditions. It was found that manganese compounds can be easily recovered in the form of manganese sulfate, manganese carbonate, and manganese oxide. In particular, for insoluble leaching residues containing manganese, high-purity manganese sulfate is produced through acid leaching and solvent extraction in two steps or less, followed by introduction of alkali metal carbonate or alkali metal hydroxide, heat treatment, etc., respectively, in various application fields It was found that high purity manganese compounds can be recovered, thereby completing the present invention.

The waste cathode active material powder of the present invention is obtained from a cathode active material for a lithium secondary battery that is defective or discarded in the manufacturing process, and in particular, a Ni-Co-Mn (NCM) ternary waste cathode active material is used. The collected waste cathode active material is prepared as a powder of waste cathode active material through roasting and a predetermined powdering process. In the waste cathode active material powder, nickel (Ni), cobalt (Co), manganese (Mn), lithium (Li), trace amounts of aluminum (Al), copper (Cu), iron (Fe), calcium (Ca), etc. This is mixed.

The method for recovering a manganese compound from a waste cathode active material of the present invention comprises dissolving the waste cathode active material powder in an aqueous solution of sulfuric acid to recover valuable metals such as cobalt, nickel, and lithium as a leachate and, in the case of manganese, as an insoluble residue.

On the other hand, the leachate is filtered and separated into an insoluble residue and a leachate. Valuable metals such as cobalt, nickel, and lithium are dissolved in the leachate, and manganese is mostly contained in the residue (Mn 30% or more) and can be recovered.

In addition, if the residue recovered above is subjected to secondary leaching with an aqueous sulfuric acid solution, the manganese residue in the residue is concentrated to 40% or more and cobalt, nickel, and lithium are removed with a solution of 99% or more. have.

In addition, the present invention may include an organic matter removal process by heat treatment to selectively recover manganese excluding impurities such as organic matter from the recovered manganese-containing insoluble residue.

Specifically, the present invention comprises the steps of: (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; (b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; (c) dissolving a metal component including manganese by adding an aqueous acid solution and a reducing agent to the insoluble residue containing manganese; And (d) solvent extraction of the leaching solution of step (c), selectively separating and concentrating manganese _{, and recovering it as manganese sulfate (MnSO 4} ) Provides a method for recovering a manganese compound from a waste cathode active material ( Step 1). The recovered manganese sulfate may be used in the preparation of a cathode active material precursor. 2 is a flowchart illustrating a method for recovering a manganese compound according to the present invention, which will be described in detail below.

First, step (a) is a step of leaching the waste cathode active material powder with an acid aqueous solution containing sulfuric acid.

In step (a), acid leaching is preferably performed within the range of 1 to 3 times without the use of a reducing agent, and more preferably, acid leaching is performed twice. In particular, in the present invention, there is an economic advantage because an expensive reducing agent is not used in step (a). In this case, when leaching twice, the second leachate may be added to the acid leaching (first leaching) step of the spent cathode active material powder.

The leaching reaction can be carried out in such a way that the solid-liquid ratio of the waste cathode active material powder obtained through physical pretreatment and the acidic aqueous solution containing sulfuric acid is 5 mL/g or more. Considering economic feasibility such as the leaching rate of valuable metals and the size of the reactor, it is preferable to carry out in the range of 5 mL/g to 20 mL/g or less.

In this case, it is preferable that the reaction temperature in the leaching step of step (a) is 50° C. to 95° C. When the reaction temperature is less than 50℃, the leaching efficiency of nickel (Ni) and cobalt (Co) by manganese (II) is slowed down, so the leaching efficiency is lowered. it falls

In addition, the concentration of the aqueous acid solution containing sulfuric acid is preferably 2.5 to 4.5 times the molar concentration of nickel (Ni), cobalt (Co), and manganese (Mn) in the solution. When the acid concentration is less than 2.5 times, the leaching rate of cobalt (Co) and nickel (Ni) is significantly reduced, and when the acid concentration exceeds 4.5 times, the leaching rate may increase, but the pH of the leachate is very low, so The amount of neutralizing agent to neutralize to the required pH in extraction, etc.) is increased.

Step (b) is a step of filtering the leachate from the leachate of step (a) and obtaining an insoluble residue containing manganese (leach residue recovery step).

Specifically, the insoluble residue in step (b) is an insoluble residue obtained by filtering the leachate from the leachate in step (a), or the insoluble residue obtained in this way is again mixed with an acid solution containing 4 M to 6 M sulfuric acid in a solid-liquid ratio. (Ratio) The leaching solution may be an insoluble residue obtained by filtration using 7 mL/g to 15 mL/g and reacting for 4 to 8 hours. At this time, if the solid-liquid ratio between the recovered residue and the acid aqueous solution exceeds 15 mL/g, the leaching amount of manganese increases significantly depending on the amount of strong acid, and the manganese selectivity may decrease. If the solid-liquid ratio is less than 7 mL/g, the leaching rate may be slower, resulting in lower efficiency. Here, the filtered leachate may contain metals such as cobalt, copper, iron, and nickel.

The step (c) is a step of dissolving manganese in an acid aqueous solution including a reducing agent for insoluble residues including manganese.

In addition, the insoluble residue including manganese in step (c) may be a residue from which organic matter is removed by heat treatment within a temperature range of 550°C to 1000°C. When the heat treatment step is additionally performed, organic matter contained in the waste cathode active material such as a binder, a separator, and an electrolyte can be removed, thereby helping to recover a high-purity manganese compound.

The reducing agent used in step (c) is hydrogen peroxide (H ₂ O ₂ ), sulfur dioxide (SO ₂ (g)), sodium metabisulfite (Na ₂ S ₂ O ₅ ), potassium metabisulfite (K ₂ S _{2 )} O ₅ ), sodium hydrogen sulfite (NaHSO ₃ ), potassium bisulfite (KHSO ₃ ), sodium hyposulfite (Na ₂ S ₂ O ₃ ), iron sulfide (FeS), and ferrous sulfate (FeSO ₄ ) One selected from the group consisting of It may be above, but it is not necessarily limited thereto as long as it is used in the art.

The reducing agent in step (c) may be added in an amount of 0.7 to 1.5 equivalents based on the manganese content in the strong acid leaching aqueous solution, but this can be adjusted depending on the process conditions.

In addition, in order to increase the leaching rate and efficiency of manganese, the step (c) is preferably performed within a temperature range of 25° C. to 70° C. for 40 minutes to 90 minutes.

In step (c), the metal component may include one or more valuable metals selected from the group consisting of manganese, copper, iron, cobalt and nickel.

In addition, in step (d), impurities such as copper, iron, and nickel are removed from the leaching aqueous solution using a solvent extraction method from the manganese leaching solution recovered in step (c), and concentrated and crystallized to obtain high purity manganese sulfate (MnSO ₄ ) is the step to recover.

The acid used in step (d) is at least one inorganic acid selected from the group consisting of sulfuric acid, hydrochloric acid, and nitric acid; or at least one organic acid selected from the group consisting of acetic acid, oxalic acid, citric acid, and malic acid; or mixtures thereof. At this time, the acid concentration is preferably 1 M to 3 M, and the reaction temperature is 25° C. to 70° C. for 40 to 90 minutes to increase the leaching efficiency of manganese, which may be changed depending on the reaction conditions.

After step (d), at least one alkali selected from the group consisting _{of carbon dioxide (CO 2} (g)), sodium carbonate (Na ₂ CO ₃ ), and potassium carbonate (K ₂ CO ₃ ) in the leachate that has undergone step (d) (e) of recovering the metal carbonate as manganese carbonate (MnCO ₃ ) by inputting it may include a step (e). In this case, it is preferable to recover manganese carbonate by adding alkali metal carbonate to adjust the pH range to 6 or more and 10 or less.

In addition, after step (d), the step (e)' of recovering _{manganese hydroxide (Mn(OH) 2} ) by adding alkali metal hydroxide to the leachate that has undergone step (d) may be included. In this case, the alkali metal hydroxide may be at least one selected from the group consisting of sodium hydroxide, lithium hydroxide, and potassium hydroxide. In this case, it is preferable to recover manganese hydroxide by adding alkali metal hydroxide to adjust the pH range to 7.5 or more and 10 or less.

Furthermore, the manganese carbonate recovered in step (e) or (e)' is heat-treated within a temperature range of 200°C to 500°C to recover manganese oxide (Mn ₃ O _4, Mn ₂ O ₃ ) (f) step can be done additionally. Preferably, by heat treatment at 200 ° C. to 300 ° C., manganese dioxide (MnO ₂ ) It is recoverable in the form of oxides.

When the above-mentioned steps (a) to (f) are sequentially performed, the highest purity manganese compound can be recovered. 3 is a flowchart illustrating a method of recovering manganese compounds as manganese sulfate, manganese carbonate, manganese oxide, and manganese hydroxide as a method of recovering the highest purity manganese compound through a solvent extraction method among the recovery methods of the manganese compound according to the present invention. This is an example, and recovery is possible by converting the manganese sulfate solution recovered after solvent extraction as shown in FIG. 3 into various manganese compounds of high purity.

In addition, the present invention comprises the steps of (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; (b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; and (c) dissolving a metal component including manganese by adding an aqueous acid solution and a reducing agent to the insoluble residue containing manganese; and (d) adding alkali metal carbonate or alkali metal hydroxide to the leaching solution of step (c) to recover manganese carbonate (MnCO ₃ ) or manganese hydroxide (Mn(OH) ₂ ). A method for recovering a manganese compound from (second step) is provided.

Steps (a) and (b) go through the same process as described above, and a detailed description thereof will be omitted. As shown in FIG. 2 , an alkali metal carbonate or alkali metal hydroxide is added to an acid leaching solution to recover manganese carbonate (MnCO ₃ ) or manganese hydroxide (Mn(OH) ₂ ). The recovered manganese carbonate can be used in the manufacture of fertilizers or ceramic pigments.

As described above, the alkali metal carbonate may be at least one selected from the group consisting _{of carbon dioxide (CO 2} (g)), sodium carbonate (Na ₂ CO ₃ ), and potassium carbonate (K ₂ CO _{3 ), but in the art} It is not limited as long as it can be used in

In addition, the present invention comprises the steps of (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; (b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; and (c) recovering manganese oxide by heat-treating the insoluble residue containing manganese (third process).

Steps (a) and (b) go through the same process as described above, and a detailed description thereof will be omitted. As shown in FIG. 2 , it is a method of recovering _{Mn 3} O ₄ and Mn ₂ O ₃ as manganese oxide by heat-treating an acid leaching solution. The recovered manganese oxide can be used in the manufacture of catalysts, adsorbents, and batteries.

In this case, the heat treatment in step (c) is preferably performed for 1 hour to 2 hours within a temperature range of 550 °C to 1000 °C. More preferably, it is a 600 degreeC - 800 degreeC temperature condition. If the temperature is less than 550 °C, organic matter removal may not be complete, and if it is more than 1000 °C, energy cost is excessively consumed, so it is preferable to perform within the above range.

In addition, the present invention comprises the steps of (a) leaching a waste cathode active material powder in an acid aqueous solution containing sulfuric acid; and (b) recovering manganese oxide by filtering the insoluble residue containing manganese from the leaching solution after the leaching (fourth step).

Steps (a) and (b) go through the same process as described above, and a detailed description thereof will be omitted. As shown in FIG. 2 , the manganese oxide itself is recovered from the acid leaching solution, and the recovered manganese oxide (including organic matter) can be used as a raw material for steelmaking or steelmaking.

Therefore, in the method for recovering manganese compounds according to the present invention, the waste cathode active material powder is first and secondly leached into an aqueous acid solution without the use of a reducing agent, the leaching solution is filtered, and the remaining insoluble leaching residue is subjected to acid leaching and solvent under predetermined conditions. Various manganese compounds in the form of manganese sulfate, manganese carbonate, and manganese oxide can be easily recovered by performing extraction, alkali metal carbide or alkali metal hydroxide input, and heat treatment.

In addition, since the present invention does not require the prior separation of manganese, the process of separating and recovering cobalt and nickel is simplified, and there is an advantage in that manufacturing costs can be reduced by not using a neutralizing agent used to recover manganese, and manganese is recovered from the residue. In the case of applying the solvent extraction process to this, high-purity manganese compounds can be recovered with a reduced process (two steps or less) than the existing process.

Hereinafter, the present invention will be described in more detail by way of Examples. However, the present invention is not limited by these examples.

<Reference Example 1>

1 kg of waste cathode active material powder having an average particle size of 75 μm or less having a content of [Table 1] was prepared.

Raw material composition of waste cathode active material powder element Co Fe Mn Cu Ca Al Ni Li LOI (%) Content (wt%) 11.22 0.43 9.40 0.40 0.01 0.71 25.95 4.79 4.4 - LOI, Loss on Ignition

<Reference Example 2> 1st acid leaching - 2nd acid leaching

The waste cathode active material powder prepared in Reference Example 1 was leached using a sulfuric acid solution without the addition of a reducing agent, and the leaching results are shown in [Table 2]. Specifically, a 2.5 M sulfuric acid solution was used in the waste cathode active material powder prepared in Reference Example 1 at a solid-liquid ratio of 10 mL/g, and the leaching reaction was performed at 80 ° C. for 4 hours to obtain the leaching concentration of each metal. .

In the primary leachate, cobalt, nickel, and lithium were dissolved at leaching rates of 80%, 90%, and 93%, respectively, while manganese was 594 mg/L in solution, which was less than 3%. Through these results, it was confirmed that valuable metals except for manganese were selectively leached in the case of primary acid leaching without using a reducing agent.

Secondary leaching was performed to recover undissolved cobalt, nickel and lithium from the first leaching solution. The second leaching did not use a reducing agent as in the first leaching. At this time, as the reaction conditions, a 4 M sulfuric acid solution was used at a solid-liquid ratio of 7 mL/g, and the leaching reaction was performed at a reaction temperature of 80° C. for 4 hours.

After primary and secondary acid leaching, the leaching rates of cobalt, nickel and lithium were improved to more than 99%, whereas manganese was present in almost trace amounts at 41 mg/L in the leaching solution. This means that most of the manganese is contained in the residue and recovered. In addition, the secondary leachate could be used as the primary leachate for the positive electrode active material.

Leaching result of waste cathode active material powder division Leachate (mg/L) Leaching rate (%) Co Ni Mn Li Co Ni Mn Li primary leaching 10,350 27,080 594 4,482 80 90 3.1 99 secondary leaching 5,029 5,938 41 30 99 99 6.5 99.9

<Reference Example 3> Manganese leaching residue - acid leaching

With respect to the manganese-containing insoluble residue prepared in Reference Example 2, sulfuric acid leaching was performed to recover _{high-purity manganese sulfate (MnSO 4 ).} Specifically, the insoluble residue containing manganese and sulfuric acid aqueous solution prepared in Reference Example 2 were used at a solid-liquid ratio of 0.05 g/mL, but 6 vol% hydrogen peroxide (H ₂ O ₂ ) (reducing agent) was added and leached at 50° C. for 1.5 hours. The reaction was carried out (acid leaching with reducing agent was carried out). [Table 3] shows the results of analyzing the composition of the filtrate after acid leaching. As shown in [Table 3], cobalt and nickel remaining in the residue were leached at 512 mg/L and 291 mg/L, respectively, and the leaching filtrate containing more than 21,780 mg/L of manganese could be recovered.

division Co Ni Mn Cu Fe Al Ca Li Leach filtrate (mg/L) 512 291 21,780 118 174 - - - After solvent extraction removal
(mg/L) 297 - 150,800 - - - - -

<Example 1> Manganese leaching residue-acid leaching-solvent extraction-manganese sulfate recovery (first step)

Manganese extraction of 2-ethylhexylphosphate (D2EPHA) diluted with a kerosene-based diluent to a concentration of 25% with a kerosene-based diluent in order to concentrate only the manganese excluding impurities such as copper and iron from the manganese-containing leaching filtrate obtained in Reference Example 3 to a high purity zero was used. The volume ratio of the organic phase (D2EPHA) and the aqueous phase (leaching solution) was set to 2, and the manganese was extracted from the organic phase by extraction in one stage at an equilibrium pH of 3.8. Manganese extracted in the organic phase was stripped with 2 M sulfuric acid at an organic phase/water ratio of 10, and the manganese was recovered as a manganese sulfate solution having a concentration of 150 g/L (Table 3).

<Example 2> Manganese leaching residue - acid leaching - solvent extraction - alkali metal carbide input - manganese carbonate recovery

In Example 1 shown in Table 5, sodium carbonate was added to the leaching filtrate recovered by sulfuric acid leaching to recover manganese carbonate. Specifically, the manganese carbonate precipitation recovery conditions were adjusted by adding sodium carbonate to a pH of 6 to 8 of the neutralization solution, and the reaction temperature was 50° C. and the reaction time was 250 rpm for 1 hour to recover manganese carbonate.

<Example 3> Manganese leaching residue - acid leaching - solvent extraction - alkali metal carbide input - heat treatment - manganese oxide recovery

The manganese carbonate recovered in Example 2 was always heat-treated at a temperature of 550° C. to recover manganese oxide.

<Example 4> Manganese leaching residue - acid leaching - alkali metal carbide input - manganese carbonate recovery (second step)

After adjusting the pH to 6 to 8 by adding sodium carbonate to the leachate recovered in Reference Example 3, the reaction temperature was 50° C. and the reaction time was 1 hour to recover manganese carbonate.

<Example 5> Manganese leaching residue-heat treatment-manganese oxide recovery (third step)

The manganese-containing insoluble residue prepared in Reference Example 2 was heat-treated at 750° C. for 60 minutes to recover _{manganese oxide (Mn 3} O _4. Mn ₂ O _{3 ).}

<Experimental Example 1> Components of insoluble residues containing manganese, XRD and TG-DTA analysis

The components of the residue recovered after secondary leaching obtained in Reference Example 2 were analyzed and shown in Table 4 below. As a result of [Table 4], the quality of manganese (Mn) was improved to 47% or more, and it was present in a concentration 4 times or more in the content (Table 1) contained in the raw material. In addition, some undissolved cobalt remained within about 0.7%.

Next, the residue recovered after secondary leaching was dried and then XRD-analyzed and shown in FIG. 4 . As shown in Figure 4, the chemical crystal form of the residue is manganese oxide, that is, in the form of H _1.78 Na _0.22 Mn ₈ O ₁₆ ·2.4H ₂ O in the form of an oxide with low crystallinity in which Mn(III) and Mn(IV) are mixed. was present, and cobalt and nickel peaks were not observed.

In addition, the residue recovered after secondary leaching was dried and analyzed by TG-DTA, as shown in FIG. 5 . As shown in FIG. 5, a ^{broad peak was observed in the vicinity of 2θ 25 o} , which is determined to be analyzed because organic substances contained in the raw material of the waste cathode active material remained in the residue.

Composition of the residue after secondary leaching residue composition Co Ni Mn Li wt% 0.74 0.18 47.1 0.02

<Experimental Example 2> Manganese sulfate (MnSO ₄ ) to confirm the number of

The components of the manganese sulfate recovered in Example 1 were analyzed and shown in [Table 5]. As shown in [Table 5], the manganese sulfate solution recovered after stripping had copper, iron, and nickel impurities present in the leachate removed, and manganese sulfate at a high concentration of 150 g/L or more containing about 300 mg/L cobalt ( MnSO ₄ ) It can be confirmed that the recovery.

Manganese sulfate recovery division Co Ni Mn Cu Fe Al Ca Li After solvent extraction removal
(mg/L) 297 - 150,800 - - - - -

<Experimental Example 3> Manganese carbonate (MnCO ₃ ) to confirm the number of

As shown in [Table 6], the composition of the manganese compound recovered in Example 2 was in the form of a high-purity manganese compound in which manganese was present in at least 47% and co-precipitated cobalt and calcium were contained within 1% as impurities. .

The recovered manganese carbonate was subjected to XRD analysis. 6 is an XRD analysis result of the recovered manganese, and it was confirmed that the precipitate was mostly present as _{manganese carbonate (MnCO 3 ).}

Manganese carbonate recovery element Co Ni Mn Ca Li MnCO ₃ (%) Content (wt%) 0.83 - 47.36 0.03 - 99.08

<Experimental Example 4> Manganese oxide (Mn ₃ O ₄ , Mn ₂ O ₃ ) to confirm the number of

On the other hand, Figure 5 is the result of XRD analysis of the insoluble residue containing manganese prepared in Reference Example 2, Mn(III) and Mn(IV) in the form of _{H 1.78} Na _0.22 Mn ₈ O ₁₆ 2·4H _{2 O} It was confirmed that the mixed crystal existed in the form of an oxide with low crystallinity, and was recovered in a state containing organic matter. In order to determine the organic matter removal temperature by heat treatment, the weight change was observed by raising the temperature from 25° C. to 900° C. under nitrogen branching for the manganese-containing insoluble residue prepared in Reference Example 2 above. The weight loss was observed at a peak around 93°C, which is weight loss due to moisture, and at 300°C and 534°C due to organic materials included in the sample such as organic binder, electrolyte, and carbon. Based on this, it was determined that if the leaching residue was subjected to heat treatment at at least 550°C, impurities such as organic matter contained in the sample could be removed and the quality of manganese could be improved.

The residue recovered after the secondary leaching (Reference Example 2) was heat-treated to 750° C., and the sample (Example 5) was analyzed after electrolysis, and is shown in [Table 7]. Manganese contained in about 47% of the residue was improved to about 70% after heat treatment at 750°C.

Manganese oxide recovery division Co Ni Mn Cu Fe Al Ca Li weight
outage(%) residue
(wt%) 0.74 - 47.14 - 0.01 - 0.02 - 750 ^o C
heat treatment
(wt%) 1.14 - 69.99 - 0.02 - 0.06 0.01 37.9

<Experimental Example 5> Manganese oxide (Mn) through XRD analysis ₃ O _4, Mn ₂ O ₃ ) Confirm

XRD of the residue recovered in Example 3 was measured and shown in FIG. 7 . As a result of FIG. 7 , manganese was _{converted into manganese oxides, Mn 3} O ₄ and Mn ₂ O ₃ , and recovered, and no organic peak was observed. Therefore, it was confirmed that high purity manganese oxide can be recovered through a heat treatment process without a wet purification process of the residue.

<Experimental Example 6> Confirmation of the conventional manganese compound recovery method and its manganese recovery efficiency

1) Manganese sulfate (MnSO ₄ ) Extraction result (5-stage solvent extraction and 2-stage washing)

Leaching was performed at 80° C. for 3 hours under the conditions of adding _{10 L of 3 M sulfuric acid solution and 5 vol% of H 2} O ₂ to 1 kg of the waste cathode active material powder having the composition shown in Table 1. After leaching, the leachate in which cobalt, nickel, and manganese were simultaneously dissolved was recovered (Table 8). After neutralizing the leachate and recovering the manganese, after solvent extraction (Mixer-Settler) in 5 steps and 2 washing steps in the ratio of aqueous phase and organic phase of 1 condition, stripping with 2 M hydrochloric acid solution, manganese having the composition shown in Table 8 recovered as a solution. As impurities in the recovered manganese sulfate, other than cobalt (Co), iron (Fe), calcium (Ca), lithium (Li), etc. were additionally present, which was compared to Example 1 in that the number of extraction stages was 5 or more. It was confirmed that the concentration of sodium hydroxide (NaOH) consumed was relatively high compared to the first-stage extraction of No. 1, which required high cost, and the purity of manganese was relatively low due to impurities.

division Co Ni Mn Cu Fe Al Ca Li Leach filtrate (mg/L) 13,450 29,590 9,906 0.8 10 - 39 11,860 After solvent extraction removal
(mg/L) 698.9 - 116,400 13 218 9.5 394 185

2) Manganese oxide (MnO ₂ ) Recovery: disodium peroxide disulfate (Na ₂ S ₂ O ₈ ) Manganese oxide recovery result using oxidizing agent

In order to selectively remove manganese from the leaching solution having the composition shown in Table 4, a precipitation experiment was performed using an oxidizing agent _{Na 2} S ₂ O _{8 . Disodium peroxide disulfate (Na 2} S ₂ O ₈ ) used as an oxidizing agent was added 1.1 times the theoretical equivalent consumed to oxidize manganese, reacted for 2 hours at a reaction temperature of 90° C., and then filtered and recovered product is shown in Table 9. The manganese oxide recovered from the leaching filtrate was recovered at a manganese concentration of 50% or more, but it was confirmed that cobalt and nickel were also lost due to co-precipitation at 3.4% and 1.8%, respectively.

division Co Ni Mn Cu Fe Al Ca Li Na ₂ S ₂ O ₈ oxidation
sediment (mg/kg) 34,660 18,150 503,200 - 8,393 - 444 -

Through these results, the conventional manganese recovery method is a process for removing manganese by precipitation by adding a reducing agent to the leaching of the spent cathode active material and adding an expensive oxidizing agent to the leachate again. In the case of manganese oxide, it can be confirmed that the loss rate due to co-precipitation of cobalt and nickel is also quite large, so it is not suitable as a manganese recovery method.

Therefore, in the present invention, since the prior separation of manganese is not required, the process of separating and recovering cobalt and nickel is simplified, and the cost of a neutralizer used to recover manganese is saved, thereby reducing manufacturing costs. In addition, when a solvent extraction process is applied to recover manganese from the residue, high-purity manganese can be recovered in a reduced process of two steps or less compared to the existing process, so the manufacturing cost of manganese can be reduced. Since manganese can be reused, it will be widely applied in terms of not only economic effects but also environmental aspects.

As the specific parts of the present invention have been described in detail above, for those of ordinary skill in the art, these specific descriptions are only preferred embodiments, and it is clear that the scope of the present invention is not limited thereto. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (16)

(a) leaching the waste cathode active material powder in an acid aqueous solution containing sulfuric acid;
(b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching;
(c) dissolving a metal component including manganese by adding an aqueous acid solution and a reducing agent to the insoluble residue containing manganese; and
(d) solvent extraction of the leaching solution of step (c), and selectively separating and concentrating manganese _{to recover manganese sulfate (MnSO 4} ). A method for recovering a manganese compound from a waste cathode active material.
The method of claim 1,
The step (a) is a method for recovering a manganese compound from a waste cathode active material, characterized in that acid leaching within the range of 1 to 3 times without the use of a reducing agent.
The method of claim 1,
The insoluble residue in step (c) is obtained by using an acid aqueous solution containing sulfuric acid at a concentration of 4 M to 6 M in the insoluble residue obtained in step (b) at a solid-liquid ratio (ratio) of 7 mL/g to 15 mL/g. A method for recovering a manganese compound from a waste cathode active material, characterized in that it is a residue obtained by leaching and filtration by reacting for 8 hours to 8 hours.
The method of claim 1,
The method for recovering a manganese compound from a waste cathode active material, characterized in that the insoluble residue in step (c) is a residue from which organic matter is removed by heat treatment within a temperature range of 550°C to 1000°C.
The method of claim 1,
The acid in step (c) is at least one inorganic acid selected from the group consisting of sulfuric acid, hydrochloric acid, and nitric acid; or at least one organic acid selected from the group consisting of acetic acid, oxalic acid, citric acid, and malic acid; Or a method for recovering a manganese compound from a waste cathode active material, characterized in that it comprises a mixture thereof.
The method of claim 1,
The reducing agent of step (c) is hydrogen peroxide (H ₂ O ₂ ), sulfur dioxide (SO ₂ (g)), sodium metabisulfite (Na ₂ S ₂ O ₅ ), potassium metabisulfite (K ₂ S ₂ O _{5 )} ), sodium hydrogen sulfite (NaHSO ₃ ), potassium bisulfite (KHSO ₃ ), sodium hyposulfite (Na ₂ S ₂ O ₃ ), iron sulfide (FeS), and ferrous sulfate (FeSO ₄ ) At least one selected from the group consisting of A method for recovering a manganese compound from a waste cathode active material, characterized in that.
The method of claim 1,
The method for recovering a manganese compound from a waste cathode active material, characterized in that the reducing agent in step (c) is used in an amount of 0.7 to 1.5 equivalents based on the manganese content.
The method of claim 1,
The step (c) is a method for recovering a manganese compound from a waste cathode active material, characterized in that it is carried out for 40 minutes to 90 minutes within a temperature range of 25°C to 70°C.
The method of claim 1,
In step (c), the metal component is at least one selected from the group consisting of manganese, copper, iron, cobalt and nickel, a method for recovering a manganese compound from a waste cathode active material.
The method of claim 1,
After step (d), at least one alkali selected from the group consisting _{of carbon dioxide (CO 2} (g)), sodium carbonate (Na ₂ CO ₃ ), and potassium carbonate (K ₂ CO ₃ ) in the leachate that has undergone step (d) A method of recovering a manganese compound from a waste cathode active material, comprising the step of (e) recovering as manganese carbonate (MnCO _{3 ) by inputting a metal carbonate.}
The method of claim 1,
After step (d), one or more alkali metal hydroxides selected from the group consisting of sodium hydroxide, lithium hydroxide, and potassium hydroxide are added to the leachate that has undergone step (d) to recover _{manganese hydroxide (Mn(OH) 2 )} (e'), a method for recovering a manganese compound from a waste cathode active material, comprising the step.
11. The method of claim 10,
The manganese carbonate is a method for recovering a manganese compound from a waste positive electrode active material, characterized in that by adding an alkali metal carbonate to adjust the pH range to 6 or more and 10 or less to recover.
12. The method of claim 11,
The manganese hydroxide is a method for recovering a manganese compound from a waste positive electrode active material, characterized in that the recovery by adding an alkali metal hydroxide to adjust the pH range to 7.5 or more and 10 or less.
12. The method of claim 10 or 11,
The manganese carbonate or manganese hydroxide recovered in the step (e) or (e') is heat-treated within a temperature range of 200 ° C to 500 ° C. A method for recovering manganese compounds from active materials.
(a) leaching the waste cathode active material powder in an acid aqueous solution containing sulfuric acid;
(b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; and
(c) dissolving a metal component including manganese by adding an aqueous acid solution and a reducing agent to the insoluble residue containing manganese; and
(d) adding an alkali metal carbonate or alkali metal hydroxide to the leaching solution of step (c) to recover manganese carbonate (MnCO ₃ ) or manganese hydroxide (Mn(OH) ₂ );
A method for recovering a manganese compound from a waste cathode active material comprising a.
(a) leaching the waste cathode active material powder in an acid aqueous solution containing sulfuric acid;
(b) filtering the manganese-containing insoluble residue from the leaching solution after the leaching; and
(c) recovering manganese oxide by heat-treating the insoluble residue containing the manganese;
A method for recovering a manganese compound from a waste cathode active material comprising a.

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