KR102500820B1 - Separation Method of Cathode Active Material and Lithium Compound Manufacturing Method Thereof - Google Patents

Abstract

The present invention relates to a method for easily separating an active material and lithium from a cathode of a battery for recycling secondary batteries. After completely peeling the cathode active material from the aluminum thin film, it is precipitated as lithium carbonate through a bubbling process in which carbonic acid is injected into an aqueous solution in which lithium ions remaining inside the cathode active material are dissolved during the peeling process, and finally, high purity and high yield at the battery anode It relates to a battery cathode active material separation method for obtaining lithium and a cathode active material for reuse and a lithium compound manufacturing method.

Description

Battery cathode active material separation method and lithium compound manufacturing method {Separation Method of Cathode Active Material and Lithium Compound Manufacturing Method Thereof}

The present invention relates to a method for separating a positive electrode active material of a battery and a method for producing a lithium compound therefrom, and more particularly, to a method for separating a positive electrode active material of a battery capable of obtaining a positive electrode active material and lithium in high purity and a high yield from a positive electrode of a waste battery, and manufacturing a lithium compound through the same It's about how.

A secondary cell battery is formed by including an anode, a cathode, a separator, and an electrolyte. At this time, a positive electrode active material composed of a metal-based mixture is adhered to an aluminum thin film, and a negative electrode active material composed of a carbon-based mixture is adhered to a copper thin film to form a battery cell. Secondary batteries are used in various electronic devices, and when charging and discharging are repeated more than a certain number of times, charge and discharge and energy efficiency gradually decrease due to solidification of a compound disposed on an anode or a cathode. Therefore, for the efficiency of electronic devices, secondary batteries need to be periodically replaced, and at this time, a large amount of secondary battery waste is generated. However, the discarded secondary battery has low charge/discharge efficiency and energy efficiency, and a new secondary battery can be manufactured after recycling by recovering the mixture used for the positive electrode or negative electrode of the secondary battery. Techniques for recovering or recycling the mixture included in these secondary batteries are disclosed in Prior Document 1. Korean Patent Publication No. 10-2020-0032663 "Method for recovering metal from secondary batteries (2020.03.26.)". At this time, in the case of a cathode of a secondary battery, a mixture of rare earth metals such as nickel, cobalt, manganese, and aluminum including lithium is used. Although the positive electrode active material is recovered or recycled using the method for recovering components of a secondary battery, such as the prior literature, there is a problem in that the recovery rate of the positive electrode active material and the purity of the recovered metals are low.

Prior Literature 1. Korea Patent Publication No. 10-2020-0032663 "Method for recovering metal from secondary battery" (2020.03.26.);'

The present invention has been made to solve the above problems, and recovers cathode active materials and lithium in high yield and purity from waste secondary batteries with low charge, discharge efficiency and energy efficiency to increase battery production cost and secondary battery recycling efficiency. There is a purpose.

In order to solve the above problems, the battery cathode active material separation method of the present invention includes a cathode separation step of separating a cathode from a battery; Heat treatment step of heat-treating the separated anode; An aqueous solution immersion step of immersing the positive electrode in an aqueous solution after the heat treatment step; an ultrasonic irradiation step of applying ultrasonic waves to the anode immersed in the aqueous solution; And a solid-liquid separation step of separating solid and liquid from the cathode; in the battery cathode active material separation method including, the heat treatment step is performed by repeatedly heating and cooling in a temperature range of 350 ° C to 450 ° C to form an aluminum thin film. As the distance between the particles of the bonded cathode active material is repeatedly contracted and expanded, the bonding force between the aluminum thin film and the cathode active material is weakened so that the peeling phenomenon easily occurs, and the ultrasonic irradiation step is performed by heating and cooling in the heat treatment step. Ultrasound is irradiated to the place where the bonding force between the aluminum thin film and the cathode active material is weakened due to the peeling phenomenon that occurred on the anode through repeated execution of A plurality of ultrasonic heads are disposed on the positive electrode, and ultrasonic waves of different frequency bands are irradiated to the positive electrode from the plurality of ultrasonic heads to completely separate the positive electrode active material particles or sintered bodies having different sizes and masses, and the positive electrode active material particles or The plurality of ultrasonic waves are alternately irradiated to change the vibration position due to the ultrasonic waves applied to the sintered body, and the battery cathode active material separation method includes a sediment recovery step of recovering precipitates precipitated in the aqueous solution after the solid-liquid separation step; And a particle size classification step of classifying aluminum and the cathode active material according to particle size in the precipitate; further includes.
In addition, in the aqueous solution immersion step, the aqueous solution is water or ethanol It is characterized in that any one of them.
Next, in the lithium compound production method using the battery cathode active material separation method of the present invention, a carbonic acid bubbling step of bubbling a carbonate aqueous solution into the separated liquid after the solid-liquid separation step; and a lithium compound recovery step of recovering a lithium compound precipitated in the liquid after the carbonic acid bubbling step, wherein the carbonate aqueous solution is an aqueous solution in which either magnesium carbonate or calcium carbonate is dissolved, and the carbonic acid bubbling step comprises: Injecting an aqueous carbonated salt solution into the aqueous lithium ion solution through a carbonic acid supply device to react the lithium dissolved in the aqueous lithium ion solution with the aqueous carbonated salt solution to precipitate solidified lithium carbonate.

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Unlike the prior art, the battery cathode active material separation method and lithium compound manufacturing method according to the above configuration can increase the secondary battery recycling efficiency by recovering the cathode active material and lithium in a high yield and high purity, and the precipitated lithium has a high purity. It is precipitated in the form of lithium carbonate and has the advantage of being usable again in the production of lithium secondary batteries without separate reprocessing.

1 is a flow chart showing a battery cathode active material separation method and a lithium compound manufacturing method of the present invention.
Figure 2 is a view showing the anode separation step of the present invention.
Figure 3 is a view showing the heat treatment step of the present invention.
Figure 4 is a view showing the aqueous solution immersion step and ultrasonic irradiation step of the present invention.
Figure 5 is a view showing an embodiment of the aqueous solution immersion step and ultrasonic irradiation step of the present invention.
6 is a view showing a method for producing a lithium compound of the present invention.

Hereinafter, the technical idea of the present invention will be described in more detail using the accompanying drawings.

Since the accompanying drawings are only examples shown to explain the technical idea of the present invention in more detail, the technical idea of the present invention is not limited to the form of the accompanying drawings.
The battery cathode active material separation method of the present invention includes a cathode separation step of separating a cathode from a battery; Heat treatment step of heat-treating the separated anode; an aqueous solution immersion step of immersing the positive electrode in an aqueous solution after the heat treatment step; an ultrasonic irradiation step of applying ultrasonic waves to the anode immersed in the aqueous solution; And a solid-liquid separation step of separating solid and liquid from the cathode; in the battery cathode active material separation method including, the heat treatment step is performed by repeatedly heating and cooling in a temperature range of 350 ° C to 450 ° C to form an aluminum thin film. As the distance between the particles of the bonded cathode active material is repeatedly contracted and expanded, the bonding force between the aluminum thin film and the cathode active material is weakened so that the peeling phenomenon easily occurs, and the ultrasonic irradiation step is performed by heating and cooling in the heat treatment step. Ultrasound is irradiated to the place where the bonding force between the aluminum thin film and the cathode active material is weakened due to the peeling phenomenon that occurred on the anode through repeated execution of A plurality of ultrasonic heads are disposed on the positive electrode, and ultrasonic waves of different frequency bands are irradiated to the positive electrode from the plurality of ultrasonic heads to completely separate the positive electrode active material particles or sintered bodies having different sizes and masses, and the positive electrode active material particles or The plurality of ultrasonic waves are alternately irradiated to change the vibration position due to the ultrasonic waves applied to the sintered body, and the battery cathode active material separation method includes a sediment recovery step of recovering precipitates precipitated in the aqueous solution after the solid-liquid separation step; And a particle size classification step of classifying aluminum and the positive electrode active material according to the particle size in the precipitate; further includes.
In addition, in the aqueous solution immersion step, the aqueous solution is water or ethanol It is characterized in that any one of them.
Next, in the lithium compound production method using the battery cathode active material separation method of the present invention, a carbonic acid bubbling step of bubbling a carbonate aqueous solution into the separated liquid after the solid-liquid separation step; and a lithium compound recovery step of recovering a lithium compound precipitated in the liquid after the carbonic acid bubbling step, wherein the carbonate aqueous solution is an aqueous solution in which either magnesium carbonate or calcium carbonate is dissolved, and the carbonic acid bubbling step comprises: Injecting an aqueous carbonated salt solution into the aqueous lithium ion solution through a carbonic acid supply device to react the lithium dissolved in the aqueous lithium ion solution with the aqueous carbonated salt solution to precipitate solidified lithium carbonate.

The drawing shown in FIG. 1 is a flow chart showing a battery cathode active material separation method (S1000) and a lithium recovery method (S2000) of the present invention. Each method is explained as follows. The battery cathode active material separation method (S1000) includes a cathode separation step (S1100), a heat treatment step (S1200), an aqueous solution immersion step (S1300), an ultrasonic irradiation step (S1400), a solid-liquid separation step (S1500), a precipitate recovery step (S1600), and a particle size classification step (S1700). Each step is explained as follows.

The positive electrode separation step (S1100) is a step of separating the positive electrode from the secondary battery, that is, the electrode cell. Before carrying out the glycolysis, the secondary battery is preferably immersed in salt water to discharge the electrical energy remaining therein, and then the discharge step is performed in advance.

The heat treatment step (S1200) is a step of heat-treating the anode separated in the anode separation step (S1100). In the heat treatment step (S1200), the heat applied to the positive electrode is heat treated to repeat the heating and cooling process, and the aluminum thin film and the particles of the positive electrode active material in the positive electrode undergo relative motion in which they repeat expansion and contraction. The bonding force of the cathode active material in the thin film is weakened, resulting in peeling. The heating and cooling of the heat treatment step (S1200) is preferably performed in the range of 350 ° C to 450 ° C.

The aqueous solution immersion step (S1300) is a step of immersing the anode in which the peeling phenomenon has occurred in the heat treatment step (S1200) in a water tank containing an aqueous solution. At this time, the aqueous solution serves as a transmission medium of the ultrasonic waves irradiated to the positive electrode in the ultrasonic irradiation step (S1400) and serves to accommodate the exfoliated positive electrode active material and lithium ions included in the positive electrode active material. At this time, the aqueous solution is preferably any one of aqueous solutions such as water (H 2 O) and ethanol (C 2 H 5 OH).

The ultrasonic irradiation step (S1400) is a step of irradiating ultrasonic waves to an anode immersed in an aqueous solution. In the heat treatment step (S1200), ultrasonic waves are irradiated to the place where the bonding force between the aluminum thin film and the positive electrode active material is weakened through the peeling phenomenon generated in the positive electrode, and the aluminum thin film and the positive electrode active material are separated from each other.

The solid-liquid separation step (S1500) is a step of separating solid and liquid from each other in a state in which the aluminum thin film and the cathode active material are separated and immersed in an aqueous solution after the ultrasonic irradiation step (S1400). The solid refers to an aluminum thin film and cathode active material solidified and immersed in a liquid, and the liquid refers to an aqueous solution in which lithium (Li) ions included in the cathode are dissolved.

The precipitate recovery step (S1600) is a step of recovering the solid, that is, aluminum and the cathode active material, separated in the solid-liquid separation step (S1500).

The particle size classification step (S1700) is a step of separating the aluminum and cathode active material recovered in the precipitate recovery step (S1600) according to particle size or metal type.

Furthermore, referring to FIG. 1, the lithium compound manufacturing method (S2000) of the present invention includes a carbonic acid bubbling step (S2100) and a lithium compound recovery step (S2200).

The carbonic acid bubbling step (S2100) is a step of bubbling by supplying a carbonate aqueous solution to the lithium ion-containing aqueous solution. Here, in the carbonic acid bubbling step (S2100), the solid-liquid separation step (S1500) is performed by performing the above-described battery cathode active material separation method (S1000), and the carbonate aqueous solution is mixed into the lithium ion aqueous solution containing lithium ions, that is, the solid-liquid separation step (S1500). It means that lithium ions and carbonate ions contained in each aqueous solution are reacted with each other to promote ionic bonding. When the carbonic acid bubbling step (S2100) is performed on the lithium ion aqueous solution, lithium reacted with the carbonate aqueous solution is precipitated as lithium carbonate (Li2CO3) in the aqueous solution.

The lithium compound recovery step (S2200) is a step of recovering lithium carbonate (Li2CO3) precipitated from the aqueous solution in which the carbonic acid bubbling step (S2100) is completed. The lithium carbonate (Li2CO3) precipitated here is high-purity lithium carbonate, and since it is precipitated in a form that can be immediately used when manufacturing a secondary battery, it has the advantage of being easy to recycle the secondary battery.

The battery cathode active material separation method (S1000) and the lithium recovery method (S2000) of the present invention described above are conceptualized and described with the drawings shown in FIGS. 2 to 6 as examples.

As shown in FIG. 2, the battery cathode active material separation method (S1000) of the present invention discharges the battery to be discarded or recycled, and then the cathode 100 is removed from the electrode composed of a cathode 100 and a cathode C separator therein. An anode separation step (S1100) is performed to separate the At this time, the anode refers to a cathode including the aluminum thin film 110 and the cathode active material 120.

3, in the heat treatment step (S1200) of the battery cathode active material separation method (S1000) of the present invention, heat treatment is performed after placing the cathode 100 in the heat treatment equipment 10. At this time, the heat treatment equipment 10 repeats heating and cooling in the temperature range of 350 ° C to 450 ° C. When the reaction occurring in the anode 100 is schematized in the heat treatment step (S1200), as shown in FIG. 3, the heat treatment equipment 10 performs temperature raising and cooling in the temperature range of T1 (low temperature) and T2 (high temperature). Repeatedly, the distance between the positive electrode active material particles 111 adhered to the aluminum thin film 120 repeats contraction and expansion. Therefore, the cathode active material 110 is finally peeled off from the aluminum thin film 120. Here, at a temperature higher than 450 ° C, a phenomenon in which the positive electrode active material 110 is fixed to the aluminum thin film 120 occurs, and at a temperature lower than 350 ° C, the peeling of the positive electrode active material 110 is smoothly performed on the aluminum thin film 120. Since it is not, it is preferable that the heat treatment step (S1200) is performed in the temperature range of 350 ° C to 450 ° C described above.

Furthermore, as shown in FIG. 4, after performing the heat treatment step (S1200) of the battery cathode active material separation method (S1000) of the present invention, the cathode 100, in which the peeling phenomenon has occurred from the cathode active material and the aluminum thin film, is placed in a water tank containing an aqueous solution 21 An aqueous solution immersion step (S1300) of immersion in (20) is performed. Here, the aqueous solution 21 is water or ethanol Any one of these is suitable. In addition, in order to facilitate the separation of the positive electrode active materials 110A and 110B and the aluminum thin films 120A and 120B from the positive electrode 100 and the acceptance of lithium ions inside the positive electrode active material, the positive electrode 100 is made into small particles as shown in FIG. It may have an embodiment capable of being pulverized and immersed in the aqueous solution 21, and a separate anode pulverization step may be included after the heat treatment step (S1200). Furthermore, after the aqueous solution immersion step (S1300), an ultrasonic irradiation step (S1400) of irradiating ultrasonic waves 31 to the anode 100 by bringing the ultrasonic head 30 close to the anode 100 immersed in the aqueous solution 21 is performed. . At this time, the aqueous solution 21 accommodated in the water tank 20 acts as a transmission medium of the ultrasonic waves 31 being irradiated. Therefore, the ultrasonic wave 31 applies microvibration to the positive electrode 100 to facilitate separation of the positive electrode active materials 110A and 110B and the aluminum thin films 120A and 120B, and lithium (Li) remaining in the positive electrode active materials 110A and 110B ) ions are dissolved in an aqueous solution to form a lithium ion aqueous solution. After performing the ultrasonic irradiation step (S1400), in the water tank 20, the positive electrode active material precipitate 1 and the solids of the aluminum thin films 120, 120A, and 120B are precipitated as solids in the aqueous solution 21.

As shown in FIG. 5, in the ultrasonic irradiation step (S1400) of the battery cathode active material separation method (S1000) of the present invention, ultrasonic waves (31A, 31B) of different frequency bands are alternately transmitted from a plurality of ultrasonic heads (30A, 30B), An embodiment in which the anode 100 is sequentially irradiated may be provided. The cathode active material 110 and the aluminum thin film 120 in which the peeling phenomenon occurred in the heat treatment step (S1200) are different in size and mass of the particles or sintered bodies of the positive electrode active material 110 separated due to the peeling phenomenon, so the aluminum thin film ( 120), the frequency band of the ultrasonic waves 31A and 31B for completely separating the cathode active material 110 may vary depending on the particles or sintered body of the cathode active material 110. Therefore, the anode 100 may be irradiated with ultrasonic waves 31A and 31B of different frequency bands, and the frequency band may be changed as necessary. Furthermore, arranging a plurality of ultrasonic heads 30A and 30B to irradiate a plurality of ultrasonic waves 31A and 31B at a plurality of positions is an ultrasonic wave 31A irradiated according to the position of the anode 100 immersed in the aqueous solution 21 , 31B) and alternately irradiating a plurality of ultrasonic waves 31A and 31B to obtain an effect of changing the vibration position of the ultrasonic wave transmitted to the particles or sintered body of the positive electrode active material 110. After performing the ultrasonic irradiation step (S1400), the aqueous solution 21 precipitates the solid positive electrode active material 110 and the aluminum thin film 120, and the lithium ions remaining inside the positive electrode active material 110 are dissolved in the aqueous solution 21 As a result, the aqueous solution 21 becomes an aqueous lithium ion solution. Thereafter, in the solid-liquid separation step (S1500), the solid positive electrode active material 110 particles, sintered body, and aluminum thin film 120 are separated from the lithium ion aqueous solution, and the separated solid positive electrode active material 110 particles, sintered body, and aluminum thin film 120 Silver is separated according to the type through the particle size classification step (S1600).

As shown in FIG. 6, the aqueous solution 21 used in each step of the battery cathode active material separation method (S1000) of the present invention becomes an aqueous lithium ion solution 22 by dissolving lithium ions. Thereafter, in the lithium compound manufacturing method (S2000) of the present invention, the carbonated salt aqueous solution 41 is injected into the lithium ion aqueous solution 22 through the carbonation supply device 40, and the lithium dissolved in the lithium ion aqueous solution 22 and the carbonated salt aqueous solution A carbonic acid bubbling step (S2100) of reacting (41) to precipitate solidified lithium carbonate (2) is performed. The lithium carbonate (2) precipitated through the carbonic acid bubbling step (S2100) is in a state that can be immediately used for manufacturing a secondary battery, and the purity of the precipitated lithium carbonate (2) is determined by lithium using a conventional secondary battery component recycling method. Its usefulness is higher than its purity. Thereafter, when the lithium carbonate (2) is not precipitated any more even after performing the carbonic acid bubbling step (S2100) in the lithium ion aqueous solution 22, the lithium compound recovery step (S2200) of recovering the solidified lithium carbonate (2) in the aqueous solution is performed to end the lithium compound manufacturing method (S2000).

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be.

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 this application, it should not be interpreted in an ideal or excessively formal meaning. don't

The present invention is not limited to the above embodiments, and the scope of application is diverse, and various modifications and implementations are possible without departing from the gist of the present invention claimed in the claims.

100: anode
C: Cathode
110: aluminum thin film
120: cathode active material
111: cathode active material particle
1: deposit of cathode active material
2: lithium carbonate compound
10: heat treatment device
20: water tank
21: aqueous solution
22: aqueous lithium ion solution
30, 30A, 30B: ultrasonic head
31, 31A, 31B: ultrasonic
40: carbonation supply device
41: aqueous carbonated salt

Claims (8)

Anode separation step of separating the cathode from the battery;
Heat treatment step of heat-treating the separated anode;
an aqueous solution immersion step of immersing the positive electrode in an aqueous solution after the heat treatment step;
an ultrasonic irradiation step of applying ultrasonic waves to the anode immersed in the aqueous solution; and
In the battery cathode active material separation method comprising a; solid-liquid separation step of separating solid and liquid from the cathode,
In the heat treatment step,
By repeating heating and cooling in the temperature range of 350 ° C to 450 ° C,
As the distance between the particles of the cathode active material adhered to the aluminum thin film is repeatedly contracted and expanded,
The bonding force between the aluminum thin film and the cathode active material is weakened so that peeling occurs easily,
The ultrasonic irradiation step,
In the heat treatment step, ultrasonic waves were irradiated to the place where the bonding force between the aluminum thin film and the cathode active material was weakened due to the peeling phenomenon generated in the anode through repeated heating and cooling,
A plurality of ultrasonic heads are placed on the anode to prevent the formation of a square where ultrasonic waves are not irradiated depending on the position of the anode immersed in the aqueous solution,
In order to completely separate cathode active material particles or sintered bodies having different sizes and masses, ultrasonic waves of different frequency bands are irradiated to the anode from the plurality of ultrasonic heads,
The plurality of ultrasonic waves are alternately irradiated to change the vibration position due to the ultrasonic waves applied to the positive electrode active material particles or the sintered body,
The battery cathode active material separation method includes a precipitate recovery step of recovering precipitates precipitated in the aqueous solution after the solid-liquid separation step; and a particle size classification step of classifying aluminum and a cathode active material from the precipitate according to particle size.
delete delete The method of claim 1, wherein in the aqueous solution immersion step, the aqueous solution is water or ethanol Battery cathode active material separation method, characterized in that any one of
delete delete In the lithium compound production method using the battery cathode active material separation method of claim 1 or 4,
a carbonic acid bubbling step of bubbling an aqueous carbonate solution into the separated liquid after the solid-liquid separation step; and
A lithium compound recovery step of recovering a lithium compound precipitated in the liquid after the carbonic acid bubbling step; includes,
The aqueous carbonate solution is an aqueous solution in which either magnesium carbonate or calcium carbonate is dissolved,
The carbonic acid bubbling step is a battery cathode active material separation method in which an aqueous carbonated salt solution is injected into a lithium ion aqueous solution through a carbonic acid supply device to react lithium dissolved in the lithium ion aqueous solution with an aqueous carbonated salt solution to precipitate solidified lithium carbonate. Lithium compound manufacturing method using. delete

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