KR102488124B1 - Method for recovering metals from lithium battery - Google Patents

Abstract

The present invention relates to a method for recovering high-purity metal from a lithium battery using a high-frequency pulse reverse current, comprising the steps of recovering lithium from a lithium battery, leaching a waste lithium battery from which lithium is recovered into an aqueous acid solution, and and installing an electrode in the leaching solution and applying a pulsed reverse current to recover metal compounds including nickel and cobalt.

Description

Method for recovering metals from lithium battery}

The present invention relates to a method for recovering high-purity metal from a lithium battery using high-frequency pulse reverse current.

The present invention was developed with the support of the following R&D projects.

- Ministry name: Busan Metropolitan City (full support from local governments)

- Project management (specialized) organization name: Busan Institute of Industrial Science and Innovation

- Research Project Name: Regionally Specialized Technology Development and Expansion Open Research Lab Operation Project

- Title of research project: Recovery of lithium and valuable metals from used secondary batteries and high-purity basic materials

- Contribution rate: 100%

- Name of the organization performing the project (hosting organization): Pukyong National University

- Research period: 2020.04.01 ~ 2020.12.31

Waste batteries, which are waste generated from rechargeable secondary batteries at the end of their lifespan, contain valuable metals such as nickel, cobalt, manganese, lithium, and copper. To efficiently recycle finite resources, the development of waste battery recycling technology is required. .

In order to continuously and stably secure these metal resources, lithium, cobalt, manganese, nickel, zinc, copper, etc. are selected in consideration of the ease of collection of circulating resource mixed batteries (primary and secondary batteries) generated from domestic circulating resources. Developing recycling technologies is important.

If the primary and secondary small-sized mixed battery recycling resource recycling technology develops, there is an advantage in securing raw materials for strategic mineral resources such as lithium, cobalt, manganese, nickel, zinc, copper, etc. in Korea, and environmental pollution problems caused by metal scraps. By solving the problem, the battery industry can be revitalized and the competitiveness of the manufacturing industry can be increased.

Generally known technologies for recovering valuable metals from waste lithium batteries are classified into screening technologies, dissolution technologies, and separation and purification technologies. The sorting process is a step of sorting, disassembling, cutting, and crushing waste batteries, the melting process is a step of dissolving the pulverized scrap in acid to separate and concentrate metals, and the separation and refining process is a step of separating and recovering valuable metals from other impurities. to be. It is common for the sorting process to go through sorting, dismantling, cutting, grinding, calcining, etc., and for the dissolution process, a method of leaching by adding a reducing agent such as hydrogen peroxide to an inorganic acid such as sulfuric acid or hydrochloric acid is suggested. As for the separation and purification process, electrolytic sampling method using direct current, precipitation method, solvent extraction method, etc. are suggested.

However, conventional methods have a problem in that it is difficult to control the chemical composition of the recovered metal, making it difficult to recover a metal compound with a consistent composition.

One object of the present invention is to provide a method for recovering metals having various chemical compositions to be obtained from a lithium battery using a high-frequency pulse reverse current.

A method for recovering metal from a lithium battery according to an embodiment of the present invention includes recovering lithium from the lithium battery (S 100), leaching the lithium-recovered waste lithium battery into an aqueous acid solution (S 200), and installing an electrode in the acid leach solution and applying a pulsed reverse current to recover metal compounds including nickel and cobalt (S300).

In one embodiment, the application of the pulse reverse current, after applying a constant current at a current density of 120 to 130 mA/cm ² and a time of 50 μs to 50 ms, and then applying a reverse current at a current density of 20 to 30 mA/cm ² and It is preferable to apply the pattern for a period of 50 μs to 50 ms as one pattern, and repeat the pattern one or more times.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 50 ms, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 50 ms. When the above pattern is repeated one or more times with one pattern, it is possible to recover a metal compound containing 58wt% or more of nickel and 39wt% or more of cobalt based on the total weight.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 5 ms, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 5 ms. When the above pattern is repeated one or more times, a metal compound containing 60 wt% or more of nickel and 37 wt% or more of cobalt based on the total weight can be recovered.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 500 μs, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 500 μs. When the above pattern is repeated one or more times with one pattern, it is possible to recover a metal compound containing 62 wt% or more of nickel and 34 wt% or more of cobalt based on the total weight.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 50 μs, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 50 μs. When the above pattern is repeated one or more times, a metal compound containing 65 wt% or more of nickel and 32 wt% or more of cobalt based on the total weight can be recovered.

In one embodiment, the aqueous acid solution is preferably a 35% (v/v) aqueous hydrochloric acid solution.

In one embodiment, the electrode may use graphite or platinum as an anode and titanium as a cathode.

In one embodiment, in the recovering step, the temperature of the acid leach solution is preferably maintained at 50 to 70°C.

In one embodiment, the lithium battery may be a mixture of a lithium secondary battery or a lithium primary battery and a lithium secondary battery.

According to the present invention, after leaching the effective resource of a waste battery into an aqueous acid solution to ionize it, it is possible to recover metals having various chemical compositions to be obtained differently from the case of applying a direct current by applying a pulse reverse current.

In addition, according to the present invention, it is possible to recover a metal having a consistent composition by controlling the magnitude and frequency of the constant current and reverse current of the pulse reverse current.

Figure 1 shows the waveform of the pulse reverse current.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention may have various changes and various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure.

Terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, step, operation, component, part, or combination thereof described in the specification, but one or more other features or steps However, it should be understood that it does not preclude the possibility of existence or addition of operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

A method for recovering metal from a lithium battery according to an embodiment of the present invention includes recovering lithium from the lithium battery (S 100), leaching the lithium-recovered waste lithium battery into an aqueous acid solution (S 200), and installing an electrode in the acid leach solution and applying a pulsed reverse current to recover metal compounds including nickel and cobalt (S300).

First, a step of recovering lithium from the lithium battery (S 100) is performed.

In one embodiment, the lithium battery may be a lithium secondary battery or a mixture of a lithium primary battery and a lithium secondary battery. In addition, the lithium battery may further include at least one metal selected from Si, Al, Ca, Mg, Na, K, Mn, P, and Zr, including Ni, Co, and Li.

In one embodiment, the step S 100 may be performed by injecting the lithium battery into a heat treatment furnace and performing heat treatment in the presence of an inert gas. After heat treatment, lithium in the lithium battery is converted into a separable compound, which can be separated and recovered through an additional process such as pulverization and washing. However, it is not limited thereto, and lithium may be recovered using various known techniques.

In one embodiment, the waste lithium battery from which the lithium obtained after the step S 100 is recovered may contain Li metal of 5 wt% or less based on the total weight.

Next, a step of leaching the waste lithium battery from which lithium is recovered into an aqueous acid solution (S200) is performed.

Specifically, when the waste lithium battery from which lithium is recovered is immersed in the aqueous acid solution, valuable metals (nickel, cobalt, manganese, etc.) included in the waste lithium battery are ionized. At this time, the ion concentration of the acid leach solution obtained after leaching varies depending on the material included in the spent lithium battery from which lithium is recovered.

In one embodiment, the acid aqueous solution may be a strong acid aqueous solution, preferably a 35% (v / v) hydrochloric acid aqueous solution, but is not limited thereto.

Next, an electrode is installed in the acid leach solution, and a step of recovering a metal compound including nickel and cobalt by applying a pulsed reverse current (S300) is performed.

As shown in FIG. 1 , the pulse reverse current refers to a current supplied by periodically alternating a constant current and a reverse current.

When the constant current is applied, a reaction in which metal ions dissolved in the acid leach solution are reduced to metal occurs, and when a reverse current is applied, a reaction in which the reduced metal is ionized again occurs. Therefore, by controlling the current density/time (frequency) of the constant current and reverse current, it is possible to recover a metal compound including nickel and cobalt in a desired chemical composition, unlike when a direct current is applied.

Specifically, the application of the pulse reverse current in the present invention, after applying a constant current at a current density (I _F ) of 120 to 130 mA/cm ² and a time (t _F ) of 50 μs to 50 ms, reverse current is applied at the current density ( _IR ) 20 to 30 mA/cm ² and 50 μs to 50 ms of time (t _R ) are applied as one pattern, and it is preferable to repeat the pattern one or more times.

The metal compound obtained by applying the pulse reverse current in the pattern includes nickel and cobalt, and according to the pattern, nickel is 58 wt% or more and cobalt is 32 wt% or more based on the total weight, and the weight ratio of nickel and cobalt is 1.4 - 2.1 : 1 phosphorus metal compounds can be recovered in various ways.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 50 ms, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 50 ms. When the above pattern is repeated one or more times with one pattern, it is possible to recover a metal compound containing 58wt% or more of nickel and 39wt% or more of cobalt based on the total weight.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 5 ms, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 5 ms. When the above pattern is repeated one or more times, a metal compound containing 60 wt% or more of nickel and 37 wt% or more of cobalt based on the total weight can be recovered.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 500 μs, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 500 μs. When the above pattern is repeated one or more times with one pattern, it is possible to recover a metal compound containing 62 wt% or more of nickel and 34 wt% or more of cobalt based on the total weight.

In one embodiment, in the application of the pulse reverse current, a constant current is applied at a current density of 125 mA/cm ² and a time of 50 μs, and then a reverse current is applied at a current density of 25 mA/cm ² and a time of 50 μs. When the above pattern is repeated one or more times, a metal compound containing 65 wt% or more of nickel and 32 wt% or more of cobalt based on the total weight can be recovered.

As described above, the present invention is capable of recovering metal compounds of various chemical compositions to be obtained differently from the case of applying a direct current by applying a pulse reverse current in various patterns after leaching and ionizing the effective resource of a waste battery in an aqueous acid solution. can

In addition, the ion concentration of the acid leach solution obtained after leaching varies depending on the materials included in the waste lithium battery from which lithium is recovered. By controlling the current density, frequency, pattern, etc. can be recovered

On the other hand, the electrode preferably uses graphite or platinum as an anode and titanium as a cathode, which prevents damage to the electrode when reverse current is applied, properly utilizing the effect of reverse current, and metal compound This is to ensure that the electrodeposition layer of is uniformly grown.

Also, in the recovering step, the temperature of the acid leach solution is preferably maintained at 50 to 70°C. When the temperature is maintained at less than 50° C., the mobility of ions is low, resulting in high voltage, and when the temperature exceeds 70° C., control of the ion concentration becomes difficult due to excessive moisture evaporation.

Hereinafter, various embodiments and experimental examples of the present invention will be described in detail. However, the following examples are merely some examples of the present invention, and the present invention should not be construed as being limited to the following examples.

[Example]

After recovering lithium from the lithium secondary battery using a known heat treatment method, the chemical composition of the solid waste battery from which lithium was recovered is shown in Table 1 below.

Si Al Ca Mg Na K Mn P Zr Ni Co Li 0.293 0.126 0.029 0.007 0.066 0.018 12.38 0.020 0.501 40.78 13.34 4.44

Next, the waste battery solid from which lithium was recovered was put into a 35% (v/v) aqueous hydrochloric acid solution and ionized and leached. The metal ion concentration (mg/L) of the acid leach solution is shown in Table 2 below.

Si Al Ca Mg Na K Mn Zr Ni Co Li Ba 41.5 71.0 10.8 3.4 26.1 3.4 6500 92.8 18070 5669 1619 2.1

Then, the acid leaching aqueous solution was maintained at 60 ° C, a titanium plate was installed as a cathode and a platinum net was installed as an anode in the aqueous solution, and then the form of pulse reverse applied current was changed according to the conditions shown in Table 3 and FIG. Cobalt and nickel were electro-harvested for 1 hour.

[Comparative Example 1]

Instead of a pulsed reverse current, a direct current (DC) of 50 mA/cm ² was applied to electrolytically collect cobalt and nickel dissolved in an aqueous solution for 1 hour.

[Comparative Example 2]

Instead of a pulse reverse current, only a pulse constant current of 100 mA/cm ² was applied to electrolytically collect cobalt and nickel dissolved in an aqueous solution for 1 hour.

The specific experimental conditions of Examples and Comparative Examples 1 and 2 and the cobalt and nickel concentrations of the recovered metal compounds are shown in Table 3 below.

frequency _{tF tR} I _F I _R Average
current density Pre-complex chemical composition (wt.%) nickel cobalt DC
(Comparative Example 1) 0 - - - - 50 mA/cm ² 61.86 36.8 case 1
(Comparative Example 2) 10 50ms 50ms 100 mA/cm ² 0 50 mA/cm ² 53.74 45.03 100 5ms 5ms 100 mA/cm ² 0 50 mA/cm ² 62.53 35.73 1000 500 µs 500 µs 100 mA/cm ² 0 50 mA/cm ² 64.03 34.62 10000 50 µs 50 µs 100 mA/cm ² 0 50 mA/cm ² 68.51 30.12 case 2
(Example) 10 50ms 50ms 125 mA/cm ² 25 mA/cm ² 50 mA/cm ² 58.21 39.59 100 5ms 5ms 125 mA/cm ² 25 mA/cm ² 50 mA/cm ² 60.38 37.51 1000 500 µs 500 µs 125 mA/cm ² 25 mA/cm ² 50 mA/cm ² 62.25 34.93 10000 50 µs 50 µs 125 mA/cm ² 25 mA/cm ² 50 mA/cm ² 65.65 32.32

Referring to Table 3, in the case of the example (case 2) in which the pulse reverse current was applied, it could be confirmed that metal compounds of different compositions were recovered according to the current density and frequency, and metals having a different chemical composition than those in the case of applying a direct current It can be confirmed that the compound is recovered.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

Claims (10)

recovering lithium from the lithium battery;
Leaching the waste lithium battery from which lithium is removed in an aqueous acid solution; and
Recovering a metal compound including nickel and cobalt by installing an electrode in an acid leach solution and applying a pulse reverse current that periodically alternates between a constant current and a reverse current to recover a metal compound including nickel and cobalt,
After applying the pulse reverse current, a constant current was applied at a current density of 120 to 130 mA/cm ² and a time of 50 μs to 50 ms, and then a reverse current was applied at a current density of 20 to 30 mA/cm ² and 50 μs to 50 ms Applying at a time of is one pattern, and the pattern is repeated one or more times,
A first metal compound containing 58wt% or more of nickel and 39wt% or more of cobalt based on the total weight; a second metal compound containing 60 wt% or more of nickel and 37 wt% or more of cobalt; a third metal compound containing 62 wt% or more of nickel and 34 wt% or more of cobalt; and a fourth metal compound containing 65 wt% or more of nickel and 32 wt% or more of cobalt.
A method for recovering a metal compound having a constant composition of nickel and cobalt from a lithium battery.
delete delete delete delete delete According to claim 1,
Characterized in that the aqueous acid solution is a 35% (v / v) aqueous hydrochloric acid solution,
A method for recovering a metal compound having a constant composition of nickel and cobalt from a lithium battery.
According to claim 1,
Characterized in that the electrode uses graphite or platinum as an anode and titanium as a cathode,
A method for recovering a metal compound having a constant composition of nickel and cobalt from a lithium battery.
According to claim 1,
In the recovering step, the temperature of the acid leach solution is maintained at 50 to 70 ° C.
A method for recovering a metal compound having a constant composition of nickel and cobalt from a lithium battery.
According to claim 1,
Characterized in that the lithium battery is a mixture of a lithium secondary battery or a lithium primary battery and a lithium secondary battery,
A method for recovering a metal compound having a constant composition of nickel and cobalt from a lithium battery.

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