KR101792753B1 - A method for recovering lithium compound from waste comprising lithium - Google Patents

Abstract

The present invention relates to a method of collecting a lithium compound from lithium-containing waste. More specifically, the present invention relates to a lithium collecting method in which by using waste containing lithium, lithium carbonate, a lithium composite metal oxide, a lithium salt, or the like; a collecting process is performed under a reduction atmosphere after waste such as process sludge, waste water sludge, cathode active material, cathode and anode mixed material, or effluent created when a lithium-ion battery produced or discarded is mixed with high purity carbon powder. As such, the lithium collecting method is capable of separating, at high purity, a solution containing a lithium compound or lithium compound powder such as lithium carbonate from waste. According to the present invention, lithium, which is a valuable metal, is able to stably be collected at high purity by recycling lithium-containing waste, and efficient usage of resources is able to be promoted by preventing environmental pollution and improve economic efficiency.

Description

METHOD FOR RECOVERING LITHIUM COMPOUND FROM WASTE COMPRISING LITHIUM BACKGROUND OF THE INVENTION [0001]

The present invention relates to a method for recovering a lithium compound from a lithium-containing waste, and more particularly, to a method for recovering a lithium compound from a lithium-containing waste by using a waste containing lithium such as lithium, lithium carbonate, lithium composite metal oxide, The recovered process is carried out in a reducing atmosphere by mixing the produced sludge, wastewater sludge, the cathode active material, the mixture containing the anode / cathode mixture or the waste liquid with the high-purity carbon powder, thereby obtaining an aqueous solution containing the lithium compound or a lithium compound To a lithium recovery method capable of separating the powder with high purity.

Lithium is an alkali metal element belonging to two groups of periodic table 1 group. It is a rare metal used as a control rod of a reactor, a catalyst for organic synthesis, a reducing agent, a lithium battery, and an additive for various alloys.

Especially, it is used as the main material of lithium ion battery used in various electronic devices of mobile phone, room industry, automobile system, electric automobile industry, and aviation industry. As the usage of lithium ion battery is gradually increasing, demand is increasing and possibility of depletion is continuously raised .

In addition, although the amount of lithium to be used increases with the increase and the amount of waste, the lithium-containing waste contains a large amount of environmentally harmful substances, which are difficult to dispose of simply. Therefore, in order to prevent environmental pollution, It is required to develop a method of recovering lithium by recycling.

However, the conventional technique for recycling lithium is mainly limited to a method mainly for recycling from a waste lithium ion battery, and these techniques are limited to a sol-gel method or a leaching method using an acid.

Korean Patent Registration No. 10-1049937 discloses a method of recovering lithium by adding a carbonaceous material to a cathode material of a spent lithium secondary battery and then pyrolyzing in an oxidizing atmosphere in which oxygen or air is injected, Lithium carbonate (Li ₂ CO ₃ ) is not generated by pyrolysis under the same oxidizing atmosphere as that in the above, and ultimately lithium of high purity can not be recovered.

In order to solve the above problems, the present inventors have studied a method for recovering a lithium compound from a waste containing lithium. The inventors of the present invention conducted a recovery process in a reducing atmosphere by mixing the waste with the high purity carbon powder It is possible to recover an aqueous solution containing a lithium compound or a lithium compound powder such as lithium carbonate, and the recovery rate is also excellent. Thus, the present invention has been completed.

One object of the present invention is to provide a method for recovering an aqueous solution containing a lithium compound from a lithium-containing waste.

It is another object of the present invention to provide a method for recovering a lithium compound powder from a lithium-containing waste.

According to an aspect of the present invention, there is provided a method of recovering lithium by mixing carbon powder into a lithium-containing waste furnace and firing the mixture in a reducing atmosphere.

In one specific embodiment, the present invention provides a method of recovering an aqueous solution comprising a lithium compound from a lithium-containing waste comprising the steps of:

(S1) mixing the carbon powder with the lithium-containing waste;

(S2) firing the mixture of the step (S1) to a temperature of 600 to 700 ° C in a reducing atmosphere in which atmospheric oxygen is present at 0 to 3%;

(S3) pulverizing the sintered material in the step (S2), and then concentrating it after washing with water to obtain an aqueous solution containing a lithium compound;

In the present invention, the lithium-containing waste in the step (S1) includes a process sludge, a waste water sludge, a cathode active material, a cathode and a cathode mixture or a waste liquid generated during the production or disposal of a lithium ion battery, no. Further, any waste containing lithium, lithium carbonate, lithium composite metal oxide or lithium salt can be used.

In the present invention, in the case of using the lithium-containing waste, a pretreatment process such as crushing, crushing, firing of an organic material, filtration and separation of impurities can be performed in order to increase the efficiency of the process.

In one specific example, when the lithium-containing waste is a process sludge, a wastewater sludge or a waste liquid, the pretreatment process is not particularly limited thereto, but it is possible to remove impurities such as sand, soil, plastic and waste residue using a filtration membrane, separation membrane or screen .

In one specific example, when the lithium-containing waste is a waste lithium battery, a cathode active material, or a cathode and a cathode mixture, the pretreatment process may include discharging, crushing, crushing, screening, firing or dissolving processes.

The step (S1) of the present invention is a step of mixing carbon powder into lithium-containing waste. The carbon powder is a material containing carbon as a main component and is not limited to carbon black, carbon powder, carbon powder, graphite or the like. The carbon powder may contain Ca, Mg, K, Na and other impurities (such as dust, moisture and other metallic substances) as an external component of carbon, but they should not contain more than 500 ppm in total. In particular, since the carbon powder mainly contains Ca, Mg, K, and Na as an external component of carbon, a high lithium recovery rate can be achieved only if Ca, Mg, K, and Na do not exceed the above range.

That is, Ca, Mg, K, and Na are preferably contained in an amount of 0 to 500 ppm, respectively. When at least one of the content of the non-carbon component exceeds 500 ppm, the recovery rate of lithium is remarkably reduced as shown in the following examples.

In one preferred embodiment, the carbon powder can be obtained from industrial wastes.

In one specific embodiment, the carbon powder can be obtained by purification through the following process:

(S11) firing the carbon-containing powder at 700 to 900 占 폚;

(S12) treating the fired product in the step (S11) with an acid to melt the product;

(S13) washing the melt in the step (S12); And

(S14) filtering the water washed in the step (S13).

Hereinafter, a method for producing a carbon powder will be described in detail.

First, the step (S11) is a step for firing the carbon-containing powder at 700 to 900 DEG C to remove the electrolyte, organic matter or impurities in the carbon-containing powder.

If the calcination temperature is lower than 700 ° C, the organic matter or impurities may not be sufficiently removed. If the calcination temperature is higher than 900 ° C, the process time becomes longer and the cost efficiency decreases.

The carbon-containing powder can be obtained from industrial wastes. The industrial wastes include carbon, a cell wafer for a solar cell, a core material for a hot gas furnace, a graphite crucible, a hot press mold, a casting die or a lithium Batteries and the like as a main component, and can be obtained from an electrode active material of a spent lithium battery. When the carbon powder is obtained from the industrial wastes, it is possible to effectively recycle the carbon-containing wastes generated in large quantities, thereby preventing environmental pollution and enhancing the economical efficiency, thereby enabling efficient use of resources.

The step (S12) is a step of dissolving the metal components (Ca, Mg, K, Na, Al, Fe and Ti and the like) in the calcined product using an acid (sulfuric acid, hydrochloric acid, nitric acid or oxalic acid) It is preferable to carry out the process in a sealed state in order to suppress impurity contamination due to the inflow of external air to remove carbon dioxide by leaching and to increase the purity of the carbon additive by melting the fired carbon powder.

The step (S13) is a step of washing the molten material from which the impurities have been removed through the step (S12), wherein the acid component remaining in the molten material is removed and the carbon powder is selectively eluted.

Although the water washing time is not particularly limited, it is preferable that the acid component in step (S12) is sufficiently removed and the treatment is performed for 1 to 12 hours in consideration of the process efficiency.

The step (S14) is a step of obtaining a carbon powder by filtering the water washed in the step (S13). The filtration can be performed by using a screen, a filtration membrane, a membrane, a filter, or a microfilter using filtration, microfiltration, ultrafiltration or reverse osmosis, but is not limited thereto.

In order to increase the purity of the carbon powder in the above process, steps (S12) to (S14) may be repeatedly performed in consideration of the process time and economy.

Through the steps (S11) to (S14), it is possible to increase the content of carbon in the carbon additive to the purity condition required by the present invention, that is, 99.5% or more, and the carbon powder obtained through the purification process, It is possible to increase the recovery rate of the lithium compound.

In the step (S1), it is preferable that the lithium-containing waste and the carbon powder are mixed at a molar concentration (M) ratio of 1: 0.5 to 3 in the lithium contained in the waste. If the molar concentration (M) ratio of the carbon powder exceeds 3, the efficiency of the process decreases. If the molar concentration (M) is less than 0.5, the carbon powder can not sufficiently react with the lithium, so that the recovery rate of lithium is significantly reduced.

The step (S2) is a step of firing the mixture of the step (S1) at a temperature of 600 to 700 ° C in a reducing atmosphere in which oxygen is removed, wherein the organics contained in the mixture are removed and fired This is a step for reducing the mixture. In order to finally obtain a lithium compound, the reducing atmosphere should be such that oxygen in the atmosphere inside the calcining furnace is present at a maximum of 3% or less. If oxygen is present in excess of 3%, the inside of the calcining furnace becomes an oxidizing atmosphere and lithium oxide contained in the mixture can not be reduced, so that lithium carbonate (Li ₂ CO ₃ ) is not produced and the recovery rate of lithium is lowered suddenly.

The firing step in step (S2) preferably proceeds to 600 to 700 ° C, more preferably to 620 to 680 ° C. When the calcination process is less than 600 ° C., the reduction reaction of the mixture mixed in step (S 1) does not occur well. When the temperature exceeds 700 ° C., the efficiency of the reduction reaction is low and the efficiency in terms of process time and cost is reduced.

The firing process in the step (S2) proceeds for 10 to 70 minutes, preferably for 15 to 60 minutes, depending on the composition of the lithium-containing waste. If the calcination process is less than 20 minutes, the reduction reaction of the mixture does not occur well. If the calcination process is more than 70 minutes, the reduction reaction efficiency is low and the efficiency in terms of process time and cost is decreased.

In one specific embodiment, when the lithium-containing waste is a positive electrode slurry of a spent lithium battery, firing in the step (S2) is preferably performed at 620 to 640 캜 for 10 to 20 minutes, more preferably, Lt; RTI ID = 0.0 > 635 C < / RTI >

In one specific embodiment, if the lithium-containing waste is a cathode and a cathode mixture of a spent lithium battery, firing in the step (S2) is preferably performed at 660 to 680 ° C for 25 to 35 minutes, And at a temperature of 665 to 675 DEG C for 27 to 37 minutes.

In the step (S3), the sintered product in the step (S2) is pulverized, and then water is washed and concentrated to obtain an aqueous solution containing a lithium compound. The concentration method is a step of decompressing, freezing, evaporating, , Precipitation thickening, reverse osmosis thickening, etc. can be used.

In consideration of the efficiency of the process in the above-mentioned concentration process, a reduced-pressure or reverse-condensation process is preferably used, and more preferably, a reduced-pressure process is used.

When the above-described reduced-pressure concentration method is used, the temperature is preferably 35 to 45 ° C. If the temperature is lower than 35 ° C, the concentration is slowed down and the process efficiency is lowered. If it exceeds 45 ° C, the energy efficiency is decreased.

In another embodiment, the present invention relates to a process for producing a lithium compound powder such as lithium carbonate by dehydrating and drying an aqueous solution containing a lithium compound in the step (S3) after the step (S3) to recover a lithium compound powder (Step S4).

The step (S4) is a step of dehydrating and drying the aqueous solution containing the lithium compound produced in the step (S3) to recover the lithium compound powder, and drying the powder using a hot air drier or hot air to finally obtain a lithium compound powder can do.

As described above, the method for recovering the lithium compound from the lithium-containing waste of the present invention uses waste containing lithium carbonate, lithium composite metal oxide, lithium salt, or the like. , A waste water sludge, a cathode active material, a mixture containing a cathode / an anode mixture or wastewater is mixed with a high purity carbon powder to recover a lithium compound solution or a lithium compound powder such as lithium carbonate from these wastes in a reducing atmosphere, A method of recovering a lithium compound which can be separated into a lithium compound and a lithium compound can be provided. According to the present invention, by recycling lithium-containing waste, lithium, which is a valuable metal, can be recovered in high purity with high purity, and environmental pollution can be prevented, and economic efficiency can be improved and resources can be efficiently used.

1 is a flowchart showing a method of recovering a lithium compound aqueous solution or a lithium compound powder from waste containing lithium according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail to facilitate understanding of the present invention. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the following embodiments. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

Manufacturing example  One: Of the spent lithium battery  Pretreatment

The waste lithium battery was completely discharged by using a discharger, and then heat-treated in air at 300 캜 for 30 minutes, and then cut to 0.5 to 1 cm. The plastic pieces were removed using a screen, and the electrode active material was recovered and pulverized, and then iron was removed using a magnet or the like.

Example  1: From the lithium-containing waste Lithium carbonate  Recovery of aqueous solution

The carbon powder having the components shown in Table 1 was mixed with the pretreated waste lithium battery powder of Preparation Example 1. The mixing was such that the molar ratio (M) of lithium and carbon powder in the peritanium battery was 1: 1. The mixture was calcined at 650 DEG C for 40 minutes in a reducing atmosphere having an oxygen concentration of 2% in the calcining furnace. The sintered product was washed with water and then concentrated under reduced pressure at 40 DEG C to obtain an aqueous solution of lithium carbonate.

Comparative Example  1 to 8: From the lithium-containing waste Lithium carbonate  Recovery of aqueous solution

In the same conditions and processes as in Example 1, a lithium carbonate aqueous solution was obtained by using carbon powder having different purity according to the content of the contained components as shown in Table 1 below.

Test Example 1: The yield of lithium recovered from the lithium-containing waste according to the purity of the carbon powder

100 g of the lithium carbonate aqueous solution of Example 1 and Comparative Examples 1 to 8 was taken and the amount of lithium in the aqueous solution was measured using an inductively coupled plasma mass spectrometer (ICP-MS, Thermo Corp. Xseries II) Weight percent was calculated. The results of the measurement are shown in Table 1 below.

division Content of components of carbon powder (ppm) Li content (wt%) in aqueous solution Ca Mg K Na Example 1 462 387 439 424 7.2 Comparative Example 1 552 431 486 494 4.1 Comparative Example 2 483 561 440 472 4.2 Comparative Example 3 479 423 581 493 3.9 Comparative Example 4 477 436 457 584 4.0 Comparative Example 5 998 402 451 472 2.4 Comparative Example 6 463 1012 487 495 2.1 Comparative Example 7 487 454 1008 482 2.2 Comparative Example 8 492 468 449 1011 2.1

From the test results, it was confirmed that when the content of Ca, Mg, K or Na contained in the carbon additive exceeds 500 ppm, the yield of Li is drastically lowered irrespective of the kinds of these components. Therefore, it was found that the use of a high-purity carbon powder containing not more than 500 ppm of each of the above-mentioned components can significantly increase the recovery rate of lithium.

Manufacturing example  2: Pretreatment of anode slurry

The anode slurry of the spent lithium battery was recovered, dried, and then iron was removed using a magnet or the like, and impurities were removed using a 300 mesh screen.

Example  2: From the lithium-containing waste Lithium carbonate  Recovery of aqueous solution

As shown in the following Table 2, the same carbon powder as the carbon powder used in Example 1 was mixed with the pretreated cathode slurry of Preparation Example 2 above. The mixing was such that the mixing ratio of lithium and carbon powder in the positive electrode slurry was 1: 1 molar concentration (M). The mixture was fired at 630 DEG C for 15 minutes in a reducing atmosphere having an oxygen concentration of 2% inside the firing furnace. The sintered product was washed with water and then concentrated under reduced pressure at 40 DEG C to obtain an aqueous solution of lithium carbonate.

Comparative Example  9 to 16: From the lithium-containing waste Lithium carbonate  Recovery of aqueous solution

In the same conditions and processes as in Example 2, the carbon powder was mixed with the same carbon powder as Comparative Examples 1 to 8, respectively, as shown in Table 2 below.

Test Example 2: The yield of lithium recovered from the lithium-containing waste according to the purity of the carbon powder

100 g of the lithium carbonate aqueous solution of Example 2 and Comparative Examples 9 to 16 was taken and the amount of lithium in the aqueous solution was measured using an inductively coupled plasma mass spectrometer (ICP-MS, Thermo Corp. Xseries II) Weight percent was calculated. The results of the above measurements are shown in Table 2 below.

division Content of components of carbon powder (ppm) Li content (wt%) in aqueous solution Ca Mg K Na Example 2 462 387 439 424 8.7 Comparative Example 9 552 431 486 494 4.2 Comparative Example 10 483 561 440 472 4.6 Comparative Example 11 479 423 581 493 4.9 Comparative Example 12 477 436 457 584 4.2 Comparative Example 13 998 402 451 472 2.7 Comparative Example 14 463 1012 487 495 2.3 Comparative Example 15 487 454 1008 482 2.7 Comparative Example 16 492 468 449 1011 2.4

From the test results, it was confirmed that when the content of Ca, Mg, K or Na contained in the carbon additive exceeds 500 ppm, the yield of Li is drastically lowered irrespective of the kinds of these components. Therefore, it was found that the use of a high-purity carbon powder containing not more than 500 ppm of each of the above-mentioned components can significantly increase the recovery rate of lithium.

Manufacturing example  3: Pretreatment of cathode and anode mixture

The dissolved aqueous solution of the cathode and anode mixture of the spent lithium battery was dried and then used to remove impurities using a screen.

Example 3 Recovery of Lithium Carbonate Aqueous Solution from Lithium-Containing Waste According to Purity of Carbon Powder

As shown in the following Table 3, the same carbon powder as the carbon powder used in Example 1 was mixed with the pretreated cathode and cathode mixture of Preparation Example 3. The mixing was such that the mixing ratio of lithium and carbon powder in the positive electrode slurry was 1: 1 molar concentration (M). The mixture was calcined at 670 캜 for 30 minutes in a reducing atmosphere having an oxygen concentration of 2% in the calcining furnace. The sintered product was washed with water and then concentrated under reduced pressure at 40 DEG C to obtain an aqueous solution of lithium carbonate.

Comparative Example  17 to 24: From the lithium-containing waste Lithium carbonate  Recovery of aqueous solution

In the same conditions and processes as those in Example 2, the carbon powder was mixed with the same carbon powders as Comparative Examples 1 to 8, respectively, as shown in Table 3 below.

Test Example 3: The yield of lithium recovered from the lithium-containing waste according to the purity of the carbon powder

100 g of the lithium carbonate aqueous solution of Example 3 and Comparative Examples 17 to 24 was taken and the amount of lithium in the aqueous solution was measured using an inductively coupled plasma mass spectrometer (ICP-MS, Thermo Corp. Xseries II) Weight percent was calculated. The results of the measurement are shown in Table 3 below.

division Content of components of carbon powder (ppm) Li content (wt%) in aqueous solution Ca Mg K Na Example 3 462 387 439 424 8.0 Comparative Example 17 552 431 486 494 4.1 Comparative Example 18 483 561 440 472 4.0 Comparative Example 19 479 423 581 493 3.8 Comparative Example 20 477 436 457 584 4.1 Comparative Example 21 998 402 451 472 2.5 Comparative Example 22 463 1012 487 495 2.0 Comparative Example 23 487 454 1008 482 2.3 Comparative Example 24 492 468 449 1011 2.0

From the test results, it was confirmed that when the content of Ca, Mg, K or Na contained in the carbon additive exceeds 500 ppm, the yield of Li is drastically lowered irrespective of the kinds of these components. Therefore, it was found that the use of a high-purity carbon powder containing not more than 500 ppm of each of the above-mentioned components can significantly increase the recovery rate of lithium.

Examples 4 to 5: Recovery of lithium carbonate aqueous solution from lithium-containing waste according to the amount of carbon powder added

In the same conditions and processes as in Example 1, only the mixing ratio of carbon powder was varied. The blending ratio of each was such that the mixing ratio of lithium and carbon powder in the peritanium battery was 1: 0.5 (Example 4), 1: 3.0 (Example 5) and 1: 3.1 in molar concentration (M).

Comparative Examples 25 to 28: Recovery of lithium carbonate aqueous solution from the lithium-containing waste according to the amount of carbon powder added

In the same conditions and processes as in Example 1, only the mixing ratio of carbon powder was varied. The mixing ratios of the lithium battery and the carbon powder in the per lithium battery were 1: 0.3 (Comparative Example 25), 1: 0.4 (Comparative Example 26), 1: 3.1 (Comparative Example 27) ) To the molar concentration (M) ratio.

Test Example 4: Measurement of recovery and purity of lithium according to the amount of carbon powder added

The measured values for Example 1, Examples 4 to 5, and Comparative Examples 25 to 28 are shown in Table 4 below.

The amount and purity of lithium contained in each sample were measured using an inductively coupled plasma mass spectrometer (ICP-MS, Thermo Xseries II).

As shown in the following Table 4, when the mixing ratios of Example 1 and Examples 4 to 5 of the present invention were followed, it was found that the recovery rate and purity of lithium were significantly higher than those of Comparative Examples 25 to 26. In the case of Comparative Examples 27 to 28, when the addition amount of the carbon powder was 3 times or more the molar concentration of lithium in the lithium-containing waste, it was found that there was no significant difference in recovery and purity of lithium.

division Lithium: carbon powder
(Molar concentration) Lithium recovery (%) Purity of recovered lithium (%) Example 1 1: 1 98.7 99.5 Example 4 1: 0.5 94.5 99.5 Example 5 1: 3.0 99.3 99.6 Comparative Example 25 1: 0.3 79.6 98.9 Comparative Example 26 1: 0.4 75.1 98.9 Comparative Example 27 1: 3.1 99.3 99.6 Comparative Example 28 1: 3.2 99.3 99.5

Example  6 to 8: From the lithium-containing waste according to the oxygen concentration Lithium carbonate  Recovery of aqueous solution

In the same condition and process as in Example 1, the oxygen concentration in the calcining furnace was different, and the calcination was performed. Each of the atmospheric oxygen concentrations was set at 2.4% (Example 6), 2.7% (Example 7) and 3.0% (Example 8).

Comparative Example  29 to 31: From the lithium-containing waste according to the oxygen concentration Lithium carbonate  Recovery of aqueous solution

In the same condition and process as in Example 1, the oxygen concentration in the calcining furnace was different, and the calcination was performed. Each of the atmospheric oxygen concentrations was set at 3.1% (Comparative Example 29), 3.2% (Comparative Example 30), and 3.3% (Comparative Example 31).

Test Example  5: Measurement of recovery and purity of lithium according to oxygen concentration

The measured values for Example 1, Examples 6 to 8 and Comparative Examples 29 to 31 are shown in Table 5 below.

The amount and purity of lithium contained in each sample were measured using an inductively coupled plasma mass spectrometer (ICP-MS, Thermo Xseries II).

As shown in the following Table 4, it was found that the recovery rate of lithium was much higher than that of Comparative Examples 29 to 31 in Example 1 and Examples 6 to 8 of the present invention. From the results of this test, it was found that as the oxygen concentration in the calcining furnace increases, that is, the recovery rate of lithium decreases as the oxidizing atmosphere increases. In particular, when the oxygen concentration in the calcining furnace exceeds 3%, it is confirmed that the recovery rate of lithium is drastically lowered. However, no significant difference was observed in the change of purity of recovered lithium with increasing oxygen concentration.

division Oxygen concentration in the calcining furnace (%) Lithium recovery (%) Purity of recovered lithium (%) Example 1 2.0 98.7 99.5 Example 6 2.4 98.5 99.5 Example 7 2.7 98.3 99.6 Example 8 3.0 97.6 99.4 Comparative Example 29 3.1 79.1 99.1 Comparative Example 30 3.2 76.3 99.2 Comparative Example 31 3.3 71.4 99.1

Claims (6)

(S1) mixing carbon powder containing 99.75% by weight or more and less than 100% by weight of carbon and 0 to 500 ppm of Ca, Mg, K and Na, respectively, in the lithium-containing waste;
(S2) firing the mixture of the step (S1) at a temperature of 600 to 700 ° C in a reducing atmosphere in which atmospheric oxygen is present in an amount of more than 0% and not more than 3%; And
(S3) pulverizing the sintered product in the step (S2), and then concentrating it after washing with water to obtain an aqueous solution containing a lithium compound,
The carbon powder in the step (S1)
(S11) firing the carbon-containing powder at 700 to 900 占 폚;
(S12) treating the fired product in the step (S11) with an acid to melt the product;
(S13) washing the melt in the step (S12); And
(S14) a step of filtering the washed water in the step (S13), and recovering an aqueous solution containing a lithium compound from the lithium-containing waste. The method according to claim 1,
Wherein the mixture of lithium and carbon powder contained in the waste is mixed at a molar ratio (M) of 1: 0.5 to 3 in the step (S1). delete delete The method according to claim 1,
Wherein the carbon-containing powder in the step (S11) is obtained from an electrode active material of a spent lithium battery, and recovering an aqueous solution containing the lithium compound from the lithium-containing waste. The method according to any one of claims 1, 2, and 5,
The method of claim 1, further comprising, after the step (S3), dehydrating and drying the aqueous solution containing the lithium compound in step (S3) to recover the lithium compound powder (S4) How to.

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