KR101497041B1 - Method for recovering valuable metals from cathodic active material of used lithium battery - Google Patents

Abstract

The present invention relates to a method of separating a lithium compound by hydrogen reduction or carbon reduction of a cathode material of a waste lithium ion battery, separating the lithium compound into a strong acid to leach a positive electrode material of the waste lithium ion battery into a metal containing nickel, cobalt, And separating the compound. The present invention also relates to a method for recovering valuable metals. More specifically, the method of recovering the valuable metal can be economical because it can omit the step of purifying the reactant added to recover the valuable metal, and it is also possible to provide a lithium compound and a lithium compound from the positive electrode material of the spent lithium ion battery at high purity and recovery rate. Metal compounds including nickel, cobalt, and manganese can be recovered, respectively.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for recovering valuable metals from a cathode material of a waste lithium ion battery,

The present invention relates to a method for recovering a valuable metal from a cathode material of a waste lithium ion battery, and more particularly, to a method for recovering a valuable metal from a waste lithium ion battery, And a method for recovering a lithium compound and a metal compound including nickel, cobalt and manganese from a cathode material of high purity and recovery rate.

The present invention was derived from the research conducted as a part of the technical innovation development project of the Small and Medium Business Administration [Task Control Number: S2045890, Title: Development of NMC precursor and high purity lithium compound manufacturing technology using lithium ion battery scrap as raw material].

Since lithium ion batteries have high energy density and light weight characteristics, they are being used as power sources for small portable equipment. Recently, the usage of lithium ion batteries has been rapidly increasing. In recent years, it is widely used not only for small household appliances and mobile products but also as a power source for hybrid electric vehicles (HEV / EV).

Such a lithium ion battery is composed of an anode and a cathode, an organic electrolyte and an organic separator. Specifically, a lithium ion battery includes a plastic casing and an anode, a cathode, Organic separators, organic electrolytes, and Ni-coated steel casings.

On the other hand, the positive electrode of a lithium ion battery is composed of a positive electrode material, a conductor, a binder and a current collector. The active material is excellent in reversibility, low self discharge rate, high capacity, high energy density, Lithium cobalt oxide (LiCoO ₂ ), which is easy to synthesize, is widely used. In recent years, ternary lithium complex metal oxides such as Li (NiCoMn) Ox including Ni, Mn and the like are also used as a cathode material in order to reduce the amount of expensive cobalt (Co). However, all of the above-mentioned cathode materials contain at least 5% by weight of lithium and a large amount of valuable metals such as nickel, cobalt and manganese, so that they are interested in a method for recovering expensive valuable metals from the cathode material of a spent lithium ion battery Attention is being paid.

Conventionally, one of the methods for recovering valuable metals from waste lithium ion batteries is a method of dissolving a positive electrode material of a waste lithium ion battery using a strong acid such as nitric acid, sulfuric acid, hydrochloric acid, and then performing a neutralization reaction to separate and recover lithium and other metal compounds Was used. However, in the above-mentioned recovery method, since lithium and a metal compound are eluted into an acid and separated, there is a need to further process to separate a lithium compound from other metal compounds in order to use it again in the production of a lithium ion battery.

The method of recovering cobalt, nickel, and manganese, which are valuable metals, from the cathode material of a spent lithium ion battery and recovering lithium in the form of lithium carbonate using sodium carbonate can separate the lithium compound and other metal compounds separately In addition, it is economical and simple in that it is possible to omit the step of separating it additionally as compared with the method of dissolving at once using the acid. However, in the above method, sodium carbonate is contained in a large amount as impurities in the separated lithium carbonate, and there is a limit in that it is required to perform several purification steps in order to recover high purity lithium carbonate.

Accordingly, it is possible to omit the step of purifying the reactant added for recovering the valuable metal, and it is economical, and a lithium compound and a metal compound including nickel, cobalt, and manganese can be obtained at high purity and recovery rate from the cathode material of the spent lithium- It is necessary to develop a method that can be recovered.

The present invention can omit the step of purifying the reactant added to recover the valuable metal, which is economical, and it is also possible to provide a lithium compound and a metal compound including nickel, cobalt, and manganese at high purity and recovery rate from the cathode material of the spent lithium- To a method for recovering a valuable metal from a cathode material of a waste lithium ion battery capable of recovering a valuable metal.

The present invention relates to a method for separating a lithium compound by hydrogen reduction or carbon reduction of a cathode material of a waste lithium ion battery, And separating the metal compound including nickel, cobalt and manganese by leaching the positive electrode material of the waste lithium ion battery in which the lithium compound is separated into strong acid.

Hereinafter, a method for recovering a valuable metal from a cathode material of a waste lithium ion battery according to a specific embodiment of the present invention will be described in detail.

As used herein, the term "carbon-based compound" refers to a compound containing carbon and includes all organic compounds including carbon, inorganic compounds including carbon, and the like.

As used herein, the term " valuable metal "includes lithium, nickel, cobalt, and manganese.

In the present specification, the term " positive electrode material of a lithium ion battery "means a material other than a conductor, a binder and a current collector among constituent components of a positive electrode of a lithium ion battery.

According to an embodiment of the present invention, there is provided a method of separating a lithium compound by hydrogen reduction or carbon reduction of a cathode material of a waste lithium ion battery; And separating the metal compound including nickel, cobalt and manganese by leaching the positive electrode material of the waste lithium ion battery in which the lithium compound is separated into a strong acid, to recover the valuable metal.

The present inventors have conducted studies for recovering and reusing valuable metals such as lithium and nickel, cobalt, and manganese, which are contained in a large amount in the positive electrode material of a spent lithium ion battery, to reduce the positive electrode material by a specific method, And recovering the remaining valuable metal compound by leaching into the strong acid to separate the recovered valuable metal from the waste lithium ion battery at a high recovery rate.

Particularly, since the lithium metal compound is separated from the spent lithium ion battery by the hydrogen reduction or the carbon reduction method, the method for recovering the valuable metal can omit the additional step used for purifying sodium without using sodium carbonate, The lithium compound and other metal compounds can be separated and recovered in high purity, so that the step of separating them can be omitted, which is economical and simple.

According to the method for recovering a valuable metal according to one embodiment of the present invention, a valuable metal including nickel, cobalt, manganese, and lithium can be separated from the positive electrode material of a spent lithium ion battery with high purity, Since they can be directly applied to the production of the anode material, the above valuable metals can be reused more efficiently and economically.

The cathode material of the spent lithium ion battery may include at least one valuable metal selected from the group consisting of nickel, cobalt, manganese, and lithium. Specifically, the cathode material separated from the waste lithium ion battery may contain 1 to 50% by weight of nickel, 1 to 50% by weight of cobalt, 1 to 50% by weight of manganese and 1 to 10% by weight of lithium, By weight to 5% by weight.

The cathode material of the waste lithium ion battery may contain not only the metal itself but also organic or inorganic compounds of metal in various forms. Specifically, the cathode material of the waste lithium ion battery is selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium cobalt nickel manganese oxide (LiCoNiMnO ₂ ), lithium cobalt nickel oxide (LiCo 1-yN y O ₂ , 0 <y < (LiMnO ₂ ), lithium manganese phosphorus oxide (LiMnPO ₄ ), lithium iron phosphate (LiFePO ₄ ) and lithium nickel aluminum oxide (LiNi _{1 - z} Al _z O ₂ , 0.05 ≦ _z ≦ 0.5) Oxide. &Lt; / RTI &gt;

The cathode material of the spent lithium ion battery may have an average particle size in various ranges, but may preferably have a particle size (D50) of 1 to 20 mu m. When the particle size of the spent lithium ion battery is too large or small, the aforementioned hydrogen reduction or carbon reduction may not occur uniformly, and it may not be easy to efficiently separate the above-described valuable metal.

As described above, the high-purity lithium compound can be efficiently separated according to the hydrogen reduction or carbon reduction of the cathode material of the spent lithium ion battery.

The lithium compound separated by hydrogen reduction or carbon reduction may be lithium oxide, lithium hydroxide, lithium carbonate, or a mixture of two or more thereof, more preferably a lithium carbonate crystal.

The hydrogen reduction in the step of separating the lithium compound may be performed by reacting the positive electrode material of the waste lithium ion battery with the hydrogen gas. Specifically, the hydrogen reduction in the step of separating the lithium compound may include a step of charging hydrogen gas into the cathode material of the spent lithium ion battery and heating the cathode material of the spent lithium ion battery to 400 to 800 ° C.

As the hydrogen reduction reaction progresses, lithium contained in the cathode material of the waste lithium ion battery can be converted into a form of a separable compound, and the cathode material can be converted into a form in which a valuable metal other than lithium is reduced have.

The hydrogen gas may be introduced at a rate of 0.1 to 10 L / min, preferably at a rate of 0.5 to 2 L / min. When the charging rate of the hydrogen gas is out of the above range, the reduction reaction may not be efficiently performed.

After the hydrogen gas is introduced into the cathode material of the waste lithium ion battery, the cathode material and the hydrogen gas of the waste lithium ion battery are heated to 400 to 800 ° C to reduce the cathode material. In particular, the valuable metal contained in the positive electrode material may exist in the form of lithium composite metal oxide of Li (M) O ₂ (where M is Co, Ni, Mn). When they react with hydrogen gas at 400 to 800 ° C. , LiO ₂ , Co, Ni, MnO. That is, a lithium compound such as lithium oxide can be formed from the cathode material of the waste lithium ion battery by the hydrogen reduction reaction, and can be separated through a water washing process or a reaction process with carbon dioxide, which will be described later.

The heating temperature and the heating time during the reaction of the cathode material and the hydrogen gas of the waste lithium ion battery are not particularly limited, but may be specifically performed at a temperature of 400 to 800 ° C for 5 minutes to 24 hours. The heating temperature can be adjusted within the range of 400 to 800 占 폚, but preferably at a temperature of 600 to 800 占 폚. When heating is carried out in the above-mentioned preferable temperature range, the lithium recovery rate may be high. When the heating temperature is lower than 400 ° C., the reduction reaction of the composite metal oxide in the cathode material of the waste lithium ion battery does not occur due to the low temperature, so that the recovery rate of the lithium compound may be low. A side reaction such as re-coupling of the reduced lithium compound and the composite metal oxide occurs, and the recovery rate of the lithium compound may be lowered.

The heating time can be preferably adjusted in consideration of the amount of the positive electrode material of the waste lithium ion battery and the temperature condition, in the range of 5 minutes to 24 hours. If the heating time is less than 5 minutes, the reduction reaction of the cathode material may occur insufficiently. If the heating time exceeds 24 hours, the effect of increasing the recovery rate of the lithium compound with increase of the heating time is insignificant.

The cathode material and the hydrogen gas of the spent lithium ion battery can be heated at a rate of 1 DEG C / minute to 20 DEG C / minute. The rate of temperature increase can be controlled preferably in consideration of the amount of the positive electrode material of the spent lithium ion battery and the final heating temperature, and the positive electrode material can be reduced with higher reaction efficiency by heating at the heating rate within the above range.

Meanwhile, the recovering method of the valuable metal may further include a step of reacting the result of hydrogen reduction of the cathode material of the spent lithium ion battery with carbon dioxide gas. The result of hydrogen reduction may include lithium metal and lithium oxide, which can be converted into lithium carbonate by separation with carbon dioxide.

In particular, from about the moment when about two minutes have elapsed since the reaction of the hydrogen reduction product and the carbon dioxide started, a white solid lithium carbonate crystal from the lithium metal and the lithium oxide included in the hydrogen reduction product can be formed.

The carbon dioxide gas may be an inert gas such as nitrogen or air mixed in addition to carbon dioxide, and the carbon dioxide gas is not limited to a gas containing only carbon dioxide.

Meanwhile, the carbon reduction in the step of separating the lithium compound may be performed by reacting the positive electrode material of the waste lithium ion battery with the carbon-based compound. Specifically, the carbon reduction in the step of separating the lithium compound may include a step of charging the carbonaceous compound into the cathode material of the spent lithium ion battery and heating the mixture to 400 to 800 ° C.

As the carbon reduction reaction proceeds, the lithium contained in the cathode material of the waste lithium ion battery can be converted into a form of a separable compound, for example, lithium carbonate, etc. In the cathode material, Can also be converted to a reduced form.

The carbon-based compound to be added to the reduction reaction of the above-mentioned positive electrode generally refers to a compound containing carbon as defined above, and its constitution is not limited. However, in order to increase the efficiency of the reduction reaction, High carbon compounds can be used.

Specifically, as the carbon-based compound, carbon powder or activated carbon having a particle size (D50) of 1 to 10 mu m may be preferably used. The carbon powder having a particle size within the above range has a large surface area, and the reaction between the cathode material and the carbon powder of the waste lithium ion battery can be more easily performed. In particular, lithium in the cathode material can be separated into lithium compounds at a high recovery rate have.

The carbon-based compound may be added in an amount of 0.5 to 2 moles, preferably 1 to 1.5 moles, per mole of the cathode material of the waste lithium ion battery. When the carbon-based compound is added excessively, unreacted carbon may remain as an impurity, and it is preferable to mix the carbon-based compound in the molar ratio within the above range.

The carbonaceous compound may be added to the cathode material of the spent lithium ion battery and heated to 400 to 800 ° C to reduce the valuable metal contained in the cathode material. In particular, the metal complex compound contained in the positive electrode material may exist in the form of lithium composite metal oxide of Li (M) O ₂ (where M is Co, Ni, Mn) And can be reduced in the form of Li ₂ CO ₃ , Co, Ni, MnO by reaction. That is, a lithium compound such as lithium carbonate can be formed from the cathode material of the waste lithium ion battery by the carbon reduction reaction, and can be separated through a water washing process or a concentration process, which will be described later.

The heating temperature and the heating time in the reaction of the cathode material and the carbon compound of the waste lithium ion battery are not particularly limited but may be performed at a temperature of 400 to 800 ° C for 5 minutes to 24 hours. The heating temperature can be adjusted within the range of 400 to 800 占 폚, but preferably at a temperature of 600 to 800 占 폚. In the case of heating to the above preferable temperature range, the lithium recovery rate may be high.

On the other hand, when the heating temperature is lower than 400 ° C., the reduction reaction of the composite metal oxide in the cathode material of the waste lithium ion battery does not occur due to the low temperature, so that the recovery rate of the lithium compound may be low. , There is little increase in the recovery rate due to the rise in temperature, and the economical efficiency of the process may not be sufficiently secured.

The heating time can be suitably adjusted in consideration of the amount of the positive electrode material of the waste lithium ion battery and the temperature condition in the range of 5 minutes to 24 hours. If the heating time is less than 5 minutes, the reduction reaction of the cathode material may occur insufficiently. If the heating time exceeds 24 hours, the effect of increasing the recovery rate of the lithium compound with increase of the heating time is insignificant.

Meanwhile, the step of separating the lithium compound includes a step of crushing the product of hydrogen reduction or the product of carbon reduction; Or water washing step.

More specifically, the step of separating the lithium compound is a step of separating the lithium compound from the result of the hydrogen reduction produced from the heating step of the hydrogen reduction or the carbon reduction reaction or the result of the hydrogen reduction Or the step of crushing the result of the carbon reduction.

When a hydrogen gas or a carbon compound is added to the cathode material of the spent lithium ion battery and heated, massive particles including a lithium compound, a lithium composite metal oxide, and a composite metal contained in the lithium composite metal oxide may be produced, A process of crushing the lumpy particles to increase the surface area can be additionally performed in order to separate the lithium compound more efficiently.

A mill, a hammer mill, a screw mill, a roll mill, a disc mill, or a jog mill, which are generally used for grinding, May be used. However, the present invention is not limited to the above-described example. Preferably, the weight average particle diameter is 30 to 500 占 퐉. When the weight average particle diameter after pulverization is less than 30 占 퐉, the pulverized particles may not be handled easily, the process efficiency due to excessive pulverization is inferior, When the weight average particle diameter after the pulverization exceeds 500 탆, the effect of increasing the surface area of the particles is insignificant, so that the efficiency of the elution process due to pulverization may be insignificant.

The step of separating the lithium compound may further include the step of further washing the resultant product of hydrogen reduction or the product of carbon reduction with water to selectively separate the lithium compound at a high recovery rate.

The washing step may be performed without being limited to the process order. For example, it may be performed selectively after the heating step or the pulverizing step, but the lump-shaped positive electrode material produced by hydrogen reduction or carbon reduction It is preferable to crush to increase the surface area, to wash water more easily, and to separate the lithium compound separately at a high recovery rate.

At this time, the washing step may be performed by rinsing in water at 10 to 90 ° C for 10 minutes to 24 hours. In the step of washing the resultant product of lithium reduction in the form of lump or carbon resulting from carbon reduction, lithium hydroxide, It can be separated into water in the form of a lithium compound such as lithium. The aqueous solution containing the lithium compound can be separated from the resultant hydrogen reduction product or the resultant product of carbon reduction from the solid lump material which is not dissolved in water to separate the aqueous solution containing the lithium compound separately. The lithium compound crystals can be separated through a concentration process or the like.

The washing time is not limited, but may be 10 minutes to 24 hours, more preferably 1 hour to 12 hours, in consideration of solubility of the lithium compound and the like. If the water is washed for a short time, the amount of the lithium compound to be eluted may be small, and if it is washed more than 24 hours, the increase in the elution amount of the lithium compound due to the increase in washing time is insignificant.

In order to increase the purity of the lithium compound to be separated and minimize the components flowing out in the washing step, the amount of the hydrogen reduction or carbon reduction is controlled to 10 g / L to 500 g / L. &lt; / RTI &gt;

Further, a crystal form of the lithium compound can be obtained by further concentrating the aqueous solution containing the lithium compound obtained through the washing step. The lithium compound may be lithium hydroxide or lithium carbonate. The method of concentration can be selected and used as long as it can be used as a concentration method for obtaining a crystal form in an aqueous solution such as concentration under reduced pressure, freezing concentration, evaporation concentration, heating concentration, precipitation concentration, reverse osmosis concentration and the like.

After the lithium compound is separated from the cathode material of the spent lithium ion battery by the hydrogen reduction or carbon reduction described above, the resultant product obtained by separating the lithium compound is leached into strong acid, and nickel, cobalt and manganese The metal compound can be separated.

The strong acid may include sulfuric acid, nitric acid, or a mixture thereof. However, when sulfuric acid is used, a valuable metal such as nickel, cobalt, and manganese can be recovered at a relatively low concentration and a high leaching rate.

The strong acid may be 0.1 to 5 M concentration, preferably 2 to 4 M concentration. When the reaction is carried out with a strong acid having a concentration in the above range, nickel, cobalt and manganese are eluted at a high rate, and the recovery of metal compounds including nickel, cobalt and manganese may be high. However, when the concentration of the strong acid is less than 0.1M, the amount of the metal compound eluted into the strong acid may be too small. When the concentration of the strong acid exceeds 5M, the increase of the leaching amount depending on the concentration of the strong acid is insignificant It may not be ensured.

Nickel, cobalt, and manganese may be contained in the metal compound including nickel, cobalt, and manganese leached into the strong acid solution in the form of metal ions, metal oxides, metal particles, and more preferably in a metal ion state .

And, in the step of leaching the positive electrode material into a strong acid, the solid-liquid ratio of the positive electrode material of the spent lithium ion battery recovered from the lithium compound to strong acid may be 50 to 150 g / L. When the solid ratio is less than 50 g / L, the amount of leaching is small depending on the amount of strong acid, so that economical efficiency may not be sufficiently secured. If the solid ratio exceeds 150 g / L, the valuable metal is not well leached into strong acid, And the leaching rate of the metal compound of the positive electrode material into the strong acid may be low.

Meanwhile, the recovering method of the valuable metal may further include a purification step of adding an alkaline compound so that the pH of the resultant product obtained by leaching the positive electrode material of the waste lithium ion battery from which the lithium compound is separated into strong acid is 5 to 7. [

In the step of purifying a strong acid leached product of the positive electrode material of the waste lithium ion battery, the alkaline compound may be added so that the pH of the positive electrode material is 5 to 7. Impurities of the cathode material such as aluminum can be precipitated at a pH in the above range, and the cathode material can be purified by a simple process such as filtration.

The recovering method of the valuable metal may further include the step of adding an alkaline compound so that the pH of the resultant product obtained by leaching the positive electrode material of the lithium ion battery separated from the lithium compound into strong acid after the purification step can do.

The addition of the alkali compound to the resultant product obtained in the purification step is such that the pH is 11 to 13, whereby the metal compound including nickel, cobalt and manganese can be precipitated. The precipitated metal compound can be separated into high purity even by a simple process such as filtration, and the form of the separated compound can also be directly applied to the production of the positive electrode material of the lithium ion battery. Therefore, according to the method for recovering the valuable metal, the valuable metals can be recovered more efficiently and economically and recycled as the raw material of the secondary battery.

The alkali compounds can be used without limitation, a known compound that is commonly used in the art, for example, it can be used _{NaOH, KOH, Na 2 CO 3} , K 2 CO 3 NaHCO 3 , or mixtures thereof.

According to the present invention, it is possible to omit the step of purifying the reactant added for recovering the valuable metal, and it is economical and economical to use the lithium compound and the nickel compound including nickel, cobalt and manganese at high purity and recovery rate from the cathode material of the spent lithium- A method of recovering a valuable metal from a cathode material of a waste lithium ion battery capable of recovering a metal compound can be provided.

1 is a schematic view of a reducing apparatus used in the embodiment.
2 is an XRD graph of a hydrogen-reduced sample of Example 1. Fig.
3 is an XRD graph of a sample of Example 1 washed with hydrogen and then washed.
4 is a graph showing the leaching rate of lithium to the washing liquid of Example 1 washed with hydrogen and then washed.
FIG. 5 is a graph showing leaching rates of each sample for sulfuric acid for each metal. FIG.
6 is a graph showing the carbon reduction reaction rate and the weight loss rate of each of the samples according to Example 1;
7 is an XRD graph of a carbon reduced sample of Example 2. Fig.
8 is an XRD graph of a sample of Example 2 washed with water after carbon reduction.
9 is a graph showing the leaching rate of lithium into the wash liquor of Example 2 washed with water after carbon reduction.
10 is an XRD graph of the lithium carbonate powder obtained in Example 2. Fig.
11 is a SEM photograph of the lithium carbonate powder obtained in Example 2. Fig.
12 is a graph showing the leaching rate of sulfuric acid in each sample of the sample washed with water after carbon reduction in Example 2. FIG.
FIG. 13 is a graph showing the leaching rates of the samples not subjected to the carbon reduction treatment and the samples washed at 700 ° C. after the carbon reduction in Example 2 by the respective sulfuric acid concentrations.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

[ Example  1: recovery of valuable metal through hydrogen reduction]

One. Preparation of anode material samples of waste lithium ion batteries

A sample of the positive electrode material containing the metal component of the following Table 1 was prepared.

Element (parts by weight) Ni Co Mn Li Al Content 31.7 10.6 15.7 6.6 0.08

2. Recovery step of lithium compound

(1) Device

The reducing unit is composed of a heating unit, a temperature adjusting unit and a gas adjusting unit. The heating unit uses a SiC heating element. The chamber has a size of 200 mm x 200 mm x 400 mm (width x length x length) A thermocouple and a PID temperature controller were used. The gas control unit was designed to flow three types of gas, and a flow meter for 5 L / min was installed to allow hydrogen gas and nitrogen gas to flow quantitatively. A schematic view of the used reducing apparatus is shown in Fig.

(2) Hydrogen reduction step

Nitrogen gas was flowed at a rate of 1 L / min while raising the temperature inside the chamber to the reaction temperature at a rate of 5 캜 / min. When the reaction temperature was reached, 100 g of the positive electrode material sample prepared in the above step 1 was introduced into a reduction apparatus, and the reaction temperature was maintained for 1 hour while flowing hydrogen gas having a purity of 99% or more.

After the holding time, nitrogen gas was flowed until the temperature of the chamber dropped to about 200 ° C in order to block the hydrogen gas and prevent the oxidation of the chamber. In order to prevent damage of the rubber ring for sealing the chamber, Was poured into the chamber.

The other conditions were the same, and the reaction temperature was varied five times under the five temperature conditions of 400 ° C., 500 ° C., 600 ° C., 700 ° C. and 800 ° C., and the weight of the sample before and after the hydrogen reduction step Reduction ratio and the state of the sample are shown in Table 2 below.

Condition Weight of sample (g) Weight Reduction Rate (%) Reduction rate (%) The state of the sample after reduction Before reduction After reduction 400 ° C, 1h 100.21 98.81 1.4 8.4 powder 500 ° C, 1h 100.13 92.64 7.5 45.1 Lump 600 ° C, 1h 100.00 86.22 13.8 71.0 Lump 700 ° C, 1h 100.07 87.07 13.0 78.3 Lump 800 ° C, 1h 100.10 84.62 15.5 93.3 Lump

(3) Washing step

100 g of the powder of the sample subjected to the hydrogen reduction treatment was put into 1 L of water and was rinsed with water for 1 hour. Then, CO ₂ gas was flowed at a rate of 1 L / min for 30 minutes to 500 ml of the washing solution of the sample to obtain 18 g of white lithium carbonate particles.

The XRD graphs of the hydrogen-reduced sample and the sample washed after hydrogen reduction are shown in FIGS. 2 and 3, and the lithium content of the wash liquid of the sample is analyzed, and the leaching rate of lithium is shown in FIG.

* Leaching rate of lithium = lithium content of wash water solution / lithium content of initial sample

3. Separation of metal compounds including nickel, cobalt and manganese

A sample not subjected to hydrogen reduction treatment and a sample washed with water after hydrogen reduction at 500 ° C were introduced into sulfuric acid at a concentration of 1M, 2M, 3M and 4M at a liquid ratio of 100 g / L and leached in sulfuric acid.

The leaching rate of the sample with respect to sulfuric acid is shown in FIG. 5 for each metal.

4. Analyze Results

(1) According to the above Table 2, the weight reduction of the sample according to the reduction reaction using the hydrogen of Example 1 was from 400 ° C, and a large decrease of more than 13% was observed especially above 600 ° C. The reduction of the weight of the sample is caused by the water vapor generated by the reduction reaction, which is reflected in the reduction ratio, and shows a high reduction ratio of 70% or more at 600 ° C or more.

(2) The crystal change of the hydrogen reduced sample and the sample washed after hydrogen reduction in Example 1 can be evaluated by the XRD graphs of FIGS. 2 and 3. More specifically, in the 400 ℃ but Li (NCM) O ₂ peak is slightly present, the 500 ℃ not present and the Li (NCM) O ₂ peak, was a Co / Ni, MnO, Li ₂ O peak exists, 600 ℃ A peak of LiMnO ₂ began to be generated. Therefore, from the graph, it can be deduced that Co, Ni, MnO, and Li ₂ O are produced at a temperature of 500 ° C or higher because the sample is not reduced at 400 ° C and mostly exists in an initial state. However, at 600 ℃ or higher, it is assumed that the manganese oxide decomposed at high temperature reacted with lithium again to generate LiMnO ₂ .

(3) The leaching rate obtained by analyzing the lithium content of the leached solution after the hydrogen reduction reaction was found to be 75% or more at 500 ° C. or higher as shown in FIG. 4. The purity of recovered lithium carbonate was about 99% Respectively.

(4) As shown in FIG. 5, which is a graph showing the leaching rate of sulfuric acid before and after the reduction treatment of the sample and the leaching rate of sulfuric acid by concentration, the leaching efficiency of cobalt and nickel at 2M sulfuric acid concentration Respectively, by 32% and 45%, respectively, and by manganese by 90%. The leaching rate of the sample subjected to the hydrogen reduction treatment into the 3M sulfuric acid solution showed 89% of cobalt, 99% or more of nickel and 99% or more of manganese, and the cobalt, nickel and manganese It was confirmed that lean metal could be leached into sulfuric acid.

[ Example  2: recovery of valuable metal through carbon reduction]

1. Preparation of anode material samples

A sample of the positive electrode material containing the metal components of the following Table 3 was prepared.

Element (parts by weight) Ni Co Mn Li Al Content 9.6 8.2 34.7 5.4 1.3

2. Recovery step of lithium compound

(1) Carbon reduction step

500 ° C. and 600 ° C. in the same manner as in Example 1, except that 100 g of the mixture prepared by mixing the positive electrode material sample prepared in 1 and the carbon powder at a molar ratio of 1: , 700 ° C, and 800 ° C. The carbon reduction reaction rate and the weight loss rate at each temperature are shown in Tables 4 and 6.

Condition Weight Reduction Rate (%) 400 ° C, 1h 3 500 ° C, 1h 7 600 ° C, 1h 8 700 ° C, 1h 13 800 ° C, 1h 15

(2) Washing step

The sample subjected to the carbon reduction treatment was put in water at a powder liquid ratio of 40 and was washed with water for 3 hours. The XRD graphs of the carbon reduced sample and the sample washed after the carbon reduction are shown in FIGS. 7 and 8, and the lithium content of the wash liquid of the sample is analyzed, and the leaching rate of lithium is shown in FIG.

(3) Evaporation Concentration Step

Then, lithium carbonate was recovered by concentrating the wash water of the sample subjected to the carbon reduction treatment at a temperature of 70 ° C and a pressure of 100 mbar using an evaporator, and the purity of the lithium carbonate powder was about 99% or more. The XRD and SEM results of the lithium carbonate powder are shown in FIGS. 10 and 11. FIG.

3. Separation of metal compounds including nickel, cobalt and manganese

(1) The sample washed with water after the carbon reduction was leached at a liquid ratio of 100 g / L to 2 M sulfuric acid, and the leaching rate of the sample with respect to sulfuric acid was shown in FIG.

(2) A sample not subjected to the carbon reduction treatment and a sample washed with water after the carbon reduction at 700 ° C were introduced into sulfuric acid at a concentration of 1M, 2M, 3M and 4M at a liquid ratio of 100 g / L and leached in sulfuric acid. The leaching rate of the sample with respect to sulfuric acid is shown in FIG. 13 for each metal.

4. Analyze Results

(1) According to the above Table 4 and FIG. 6, the weight reduction of the sample according to the reduction reaction using the carbon of Example 2 was from 400 ° C, and a large decrease of more than 13% was observed above 700 ° C. The reduction of the weight of the sample was caused by the carbon monoxide gas generated by the reduction reaction, which was also reflected in the reduction rate, and showed a high reduction ratio of 70% or more at 700 ° C or more.

(2) The crystal change of the sample reduced in carbon and the sample washed after hydrogen reduction in Example 2 can be evaluated by the XRD graphs of FIGS. 7 and 8. More specifically, there existed a Li (NCM) O ₂ peak at 400 ° C., but the Li (NCM) O ₂ peak began to change from 500 ° C., and there existed Co, Ni, MnO and Li ₂ CO ₃ peaks at 600 ° C. . Therefore, from the graph, it can be deduced that Co, Ni, MnO, and Li ₂ CO ₃ are produced from the sample at a temperature of 500 ° C. or higher, although the sample is not reduced at 400 ° C. and is mostly present in an initial state. However, unlike in Example 1, the peak of LiMnO ₂ was not generated at 600 ° C or higher in the carbon reduction of Example 2, and it is estimated that the manganese oxide is not carbon reduced at a high temperature.

(3) The leaching rate obtained by analyzing the lithium content of the leached solution after the hydrogen reduction reaction was 60% or more as shown in FIG. 9 at 600 ° C. or higher, and the leaching rate of lithium from 600 ° C. The reason for this rapid increase is presumably because lithium reacts with carbon at 600 ° C to produce Li ₂ CO ₃ . The purity of recovered lithium carbonate was found to be about 99%. From FIGS. 10 and 11, which are XRD and SEM photographs of the lithium carbonate particles, it can be seen that the lithium carbonate is formed in the shape of an irregular shape.

(4) As shown in Figs. 12 and 13, which are graphs showing the results of leaching of sulfuric acid before and after the reduction treatment of the sample and the leaching rates of sulfuric acid according to the concentration of sulfuric acid, cobalt and nickel The leaching efficiency was improved by 40% and 45%, respectively. In the case of manganese, there was almost no leaching in the sulfuric acid before the reduction treatment, but it was improved more than 99% according to the reduction to manganese oxide after the reduction treatment. In addition, the leaching rate of the sample subjected to the carbon reduction treatment to a sulfuric acid solution of 2M or more shows 99% or more of all of cobalt, nickel and manganese, and the cobalt, nickel, It was confirmed that leaching can be carried out with sulfuric acid.

Claims (17)

Separating the lithium compound by hydrogen reduction or carbon reduction of the cathode material of the spent lithium ion battery;
Separating the metal compound including nickel, cobalt and manganese by leaching the positive electrode material of the waste lithium ion battery into which the lithium compound has been separated in strong acid;
A purification step of adding an alkaline compound so that the pH of the resultant product obtained by leaching the positive electrode material of the waste lithium ion battery from which the lithium compound is separated into strong acid is 5 to 7; And
And adding an alkaline compound so that the pH of the resultant product obtained by leaching the positive electrode material of the waste lithium ion battery into which the lithium compound is separated is separated into 11 to 13 after the purifying step.
The method according to claim 1,
Wherein the cathode material of the spent lithium ion battery has a particle size (D50) of 1 to 20 占 퐉.
The method according to claim 1,
Wherein the positive electrode material of the spent lithium ion battery comprises at least one valuable metal selected from the group consisting of nickel, cobalt, manganese, and lithium.
The method according to claim 1,
The waste cathode material for the lithium ion battery is a lithium cobalt oxide (LiCoO _2), lithium cobalt nickel manganese oxide (LiCoNiMnO _2), lithium cobalt nickel oxide _{(LiCo1-yNiyO 2, 0 <} y <1), lithium manganese oxide (LiMnO ₂ ), the lithium manganese oxide (LiMnPO _4), lithium iron phosphate (LiFePO ₄₎ and lithium-nickel-aluminum composite oxide (LiNi1-zAlzO _2, 0.05≤z≤0.5) comprises a lithium composite metal oxide at least one member selected from the group consisting of And recovering the valuable metal.
The method according to claim 1,
Wherein the lithium compound separated from the cathode material of the spent lithium ion battery comprises at least one selected from the group consisting of lithium oxide, lithium hydroxide, and lithium carbonate.
The method according to claim 1,
Wherein the hydrogen reduction includes charging hydrogen gas into the cathode material of the spent lithium ion battery and heating the battery to 400 to 800 ° C.
The method according to claim 6,
The hydrogen gas is supplied at a flow rate of 0.1 to 10 L / min,
Wherein the cathode material and the hydrogen gas of the waste lithium ion battery are heated at a temperature raising rate of 1 占 폚 / min to 20 占 폚 / min.
The method according to claim 6,
Further comprising the step of reacting the result of hydrogen reduction with carbon dioxide.
The method according to claim 1,
Wherein the carbon reduction includes a step of adding a carbonaceous compound to the cathode material of the spent lithium ion battery and heating to 400 to 800 占 폚.
10. The method of claim 9,
Wherein the carbon-based compound comprises a carbon powder having a particle size (D50) of 1 to 10 mu m.
10. The method of claim 9,
Wherein the carbon-based compound is added in an amount of 0.5 to 2 moles per mole of the cathode material of the waste lithium ion battery.
The method according to claim 1,
The step of separating the lithium compound comprises the steps of crushing the product of hydrogen reduction or the product of carbon reduction; Or water; and recovering the valuable metal.
The method according to claim 1,
Wherein the strong acid comprises at least one selected from the group consisting of sulfuric acid and nitric acid.
The method according to claim 1,
Wherein the strong acid has a concentration of 0.1M to 5M.
The method according to claim 1,
Wherein a solid-liquid ratio of the cathode material of the waste lithium ion battery recovered from the lithium compound to the strong acid is from 50 g / L to 1500 g / L.
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