WO2025116191A1 - Method for manufacturing black powder from waste battery - Google Patents

Abstract

The present invention relates to a method and system for manufacturing high-purity black powder from a waste battery. The manufacturing method and system can easily separate and remove a positive electrode current collector from a positive electrode scrap by using a predetermined organic solvent, and can selectively remove a carbon-based compound such as a conductive material or a binder from black powder from which the positive electrode current collector is removed, thus enabling the manufacture of high-purity black powder from which metals derived from a positive electrode can be easily recovered. In addition, the manufacturing method and system have the advantage of being eco-friendly since the organic solvent used during the process is reused.

Description

Method for producing black powder from waste batteries

The present invention relates to an environmentally friendly method for producing black powder having a significantly low content of carbon compounds from positive electrode scrap derived from waste batteries.

This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2023-0167700, filed on November 28, 2023, the entire contents of which are incorporated herein by reference.

Lithium secondary batteries have the advantages of high energy density, high electromotive force, and the ability to store large amounts of energy, and are widely used in various industrial fields. For example, lithium secondary batteries are used in various fields, from small portable devices such as smartphones and laptops to electric vehicles (EVs) that are expected to replace current fossil fuel vehicles in the future. Accordingly, the production of lithium secondary batteries is also gradually increasing.

However, since these lithium secondary batteries have a limited lifespan, the number of lithium secondary batteries that have reached the end of their lifespan is expected to increase gradually. Accordingly, attempts are being made to utilize waste lithium secondary batteries from environmental and/or economic perspectives.

As an example, the Toxco process for recovering lithium from a cathode is mentioned. The process cools a spent lithium secondary battery to -195℃ with liquid argon, then immerses it in a sodium hydroxide (NaOH) solution to break the battery case. Thereafter, lithium pieces of the cathode inside the battery case are floated on the solution to generate hydrogen gas. At this time, the generated hydrogen gas is discharged, causing a reaction between sodium hydroxide (NaOH) and lithium in the solution, and lithium can be recovered through the reaction in the form of lithium hydroxide (LiOH), lithium sulfide (Li ₂ SO ₄ ), lithium carbonate (Li ₂ CO ₃ ), etc. However, although the process is stable, it has limitations in that the process itself is complicated, the amount of water used in the process is excessive, and there are many byproducts such as exhaust gases.

Another example is the Sony process, which separates metal components by washing the combustion products generated by burning waste batteries. The process is a method of recovering metal components remaining in the combustion products after burning waste batteries through washing, and components such as organic electrolytes, lithium, and fluoride can be easily removed without a separate process, and only metal components, especially cobalt, can be easily recovered.

However, despite these advantages, there are problems in that excessive materials such as water and heat energy are required to perform the process, and a large amount of waste such as exhaust gas or cleaning liquid is generated after the process, which may cause environmental pollution, making it difficult to apply to industry. Above all, the above processes have low process efficiency, and it is difficult to selectively separate only the metal components derived from the positive electrode active material, so there is a limitation in that the purity of the obtained product is low.

[Prior art literature]

Republic of Korea Patent Publication No. 10-2588151

Republic of Korea Patent Publication No. 10-2022-0038442

Accordingly, the purpose of the present invention is

The present invention provides a technology for environmentally friendly manufacturing of black powder capable of selectively recovering and/or separating only metal components from positive electrode scrap derived from waste lithium secondary batteries.

To solve the above-mentioned problem,

In one embodiment of the present invention,

A method for producing black powder from positive electrode scrap derived from waste batteries,

Step (S1) of stirring a mixture of positive electrode scrap and an organic solvent at a temperature of 150°C or lower to detach the positive electrode collector contained in the positive electrode scrap and to elute the conductive material and binder contained inside the black powder with an organic solvent.

Step (S2) of filtering the above mixture to separate the positive electrode collector;

Step (S3) of obtaining a black powder by separating an organic solvent containing a conductive agent and a binder from the above mixture from which the positive electrode collector is separated, and

A step (S4) of separating the conductive material and the binder from the organic solvent containing the conductive material and the binder and recovering the organic solvent;

The organic solvent recovered in the above step (S4) is reused in at least one of the steps (S1) to (S3);

The above organic solvent provides a method for producing a black powder including at least one of trimethyl phosphate (TMP), triethyl phosphate (TEP), dimethyl formamide (DMF), dimethyl acetamide (DMAc), and dimethyl sulfoxide (DMSO).

At this time, the positive electrode scrap can be mixed with 200 mL to 900 mL of organic solvent per 100 g.

Additionally, the above step (S1) can be performed under conditions of 200 rpm to 1,000 rpm for 5 to 100 minutes.

In addition, the step (S3) of obtaining the black powder may include a step (S3-1) of centrifuging a mixture from which the positive electrode collector is separated, a step (S3-2) of decanting a supernatant of the centrifuged mixture to separate an organic solvent containing a conductive agent and a binder, and a step (S3-3) of filtering and washing a residue from which the supernatant is decanted to produce black powder.

Here, washing of the residue can be performed twice or more repeatedly with the same organic solvent as the organic solvent of the mixture.

In addition, the method for manufacturing the black powder may further include a step (S5) of further separating a conductive material included in the obtained black powder after the step (S3) of obtaining the black powder, and the further separation may be performed through a flotation selection method.

Here, the step (S5) of further separating the conductive agent may include a step (S5-1) of mixing black powder and a floating additive in a hydrophilic solvent to float the conductive agent in the black powder to the top of the solution, and a step (S5-2) of removing the conductive agent floated to the top of the solution.

Additionally, the black powder may be mixed in an amount of 0.1 to 50 wt% based on the weight of the hydrophilic solvent, and the floating additive may be mixed in an amount of 0.1 to 40 wt% based on the volume of the hydrophilic solvent.

In addition, the hydrophilic solvent may include water and at least one of C _1-4 alkyl alcohols, and the floating additive may include at least one of mineral oil, trimethyl phosphate (TMP), and triethyl phosphate (TEP).

Additionally, the step (S4) of recovering the organic solvent can be performed by distilling the organic solvent containing the conductive agent and the binder under reduced pressure.

In addition, the black powder manufactured according to the present invention may have a carbon element content of less than 5 wt% upon component analysis.

Furthermore, in one embodiment of the present invention,

In a system for manufacturing black powder from positive electrode scrap derived from waste batteries,

A stirring section that stirs a mixture of positive electrode scrap and an organic solvent to detach the positive electrode collector contained in the positive electrode scrap and elute the conductive material and binder contained inside the black powder into the organic solvent.

A filter unit that is fluidly connected to the above stirring unit and receives a stirred mixture, and filters out the positive electrode current collector from the provided mixture;

A separation unit that is fluidly connected to the above filter unit and receives a separated mixture from the positive electrode collector, and separates an organic solvent containing a conductive agent and a binder from the provided mixture to obtain a black powder; and

A distillation unit is included for separating the conductive agent and binder from the organic solvent separated in the above separation unit and recovering the organic solvent;

The organic solvent recovered from the distillation unit is supplied to at least one of the stirring unit, the filtration unit, and the separation unit and reused;

The above organic solvent provides a black powder manufacturing system including at least one of trimethyl phosphate (TMP), triethyl phosphate (TEP), dimethyl formamide (DMF), dimethyl acetamide (DMAc), and dimethyl sulfoxide (DMSO).

At this time, the separation unit may include a centrifuge.

Additionally, the distillation unit may be fluidly connected to the top of the centrifuge to provide a supernatant after centrifugation of the mixture.

In addition, the separation unit may include a filter that supports the residue of the mixture from which the supernatant has been removed after centrifugation at the bottom, and the distillation unit may be fluidly connected to the bottom of the filter to receive a washing liquid when washing the residue supported on the filter.

In addition, the black powder manufacturing system may further include a flotation separation unit that is fluidly connected to the separation unit to receive black powder and perform flotation separation to further remove a conductive material from the provided black powder.

Further, the distillation unit may include a reduced pressure distillation device.

The method and system for manufacturing black powder according to the present invention can easily separate and remove a cathode current collector from cathode scrap using a predetermined organic solvent, and can selectively remove carbon-based compounds such as a conductive agent or a binder from black powder from which the cathode current collector has been removed, thereby manufacturing high-purity black powder from which metals derived from the cathode can be easily recovered. In addition, the manufacturing method and system have an environmentally friendly advantage because the organic solvent used during the process is reused.

Figure 1 is an image of black powder manufactured according to Example 2 of the present invention.

Figure 2 is an image of a conductive material floating on top of a mixed solution taken by a flotation separation method according to the present invention.

The present invention is susceptible to various modifications and various embodiments, and specific embodiments will be described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, but should be understood to include all modifications, equivalents, or substitutes included in the technical scope of the present invention.

In the present invention, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

In addition, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only the case where it is "directly below" the other part, but also the case where there is another part in between. Furthermore, in the present application, being disposed "on" may include the case where it is disposed below as well as above.

Hereinafter, the present invention will be described in more detail.

Method for producing black powder

In one embodiment of the present invention,

A method for producing black powder from positive electrode scrap derived from waste batteries,

Step (S1) of stirring a mixture of positive electrode scrap and an organic solvent at a temperature of 150°C or lower to detach the positive electrode collector contained in the positive electrode scrap and to elute the conductive material and binder contained inside the black powder with an organic solvent.

Step (S2) of filtering the above mixture to separate the positive electrode collector;

Step (S3) of obtaining a black powder by separating an organic solvent containing a conductive agent and a binder from the above mixture from which the positive electrode collector is separated, and

A step (S4) of separating the conductive material and the binder from the organic solvent containing the conductive material and the binder and recovering the organic solvent;

The organic solvent recovered in the above step (S4) is reused in at least one of the steps (S1) to (S3);

The above organic solvent provides a method for producing a black powder including at least one of trimethyl phosphate (TMP), triethyl phosphate (TEP), dimethyl formamide (DMF), dimethyl acetamide (DMAc), and dimethyl sulfoxide (DMSO).

The method for manufacturing black powder according to the present invention refers to a method for manufacturing black powder derived from the positive electrode of a lithium secondary battery whose lifespan has expired, i.e., a spent battery, and containing a positive electrode active material as its main component.

The method for manufacturing the above black powder includes a step of mixing a mixture of a positive electrode scrap derived from a positive electrode of a spent battery and a predetermined organic solvent and stirring the mixture at a temperature of 150°C or lower to detach a positive electrode collector from the positive electrode scrap, and dissolving a conductive material and binder contained within the black powder with the organic solvent (S1).

This step (S1) refers to the process of detaching and separating the positive electrode collector from the positive electrode scrap, and dissolving the conductive material and binder inside the black powder, which is the residue, from the black powder.

Here, “black powder” refers to the black residue remaining after removing the positive electrode collector from the positive electrode separated from the waste battery. Since this black powder is derived from the positive electrode active layer containing the positive electrode active material, it contains carbon compounds such as a conductive agent such as carbon black and a binder such as polyvinylidene fluoride (PVdF) along with the positive electrode active material as the main component.

In general, black powder contains metals such as lithium, nickel, cobalt, and manganese as its main components, and is used to recover and recycle the above metals. At this time, the recovery efficiency of the metal and the purity of the recovered metal are higher when the black powder contains less impurities (i.e., carbon compounds including carbon contained in the binder, etc., and/or non-metal compounds such as fluorine (F), phosphorus (P)) other than the metal. Accordingly, a technology is utilized to remove the conductive agent or binder by volatilizing the black powder when heat-treating the black powder at high temperatures before recovering the metal from the black powder. However, the high-temperature volatilization method may cause damage to the equipment due to a trace amount of hydrogen fluoride (HF) gas generated during the thermal decomposition of the binder such as polyvinylidene fluoride (PVdF), and may induce a side reaction of the generated black powder, which may have a negative effect. In addition, the high-temperature volatilization method is likely to cause the conductive agent or binder inside the black powder to not be completely volatilized and to remain. Therefore, the high-temperature volatilization method requires a considerable amount of heat energy to completely remove the conductive agent or binder inside the black powder, so it has low economic feasibility, can cause side reactions of metals contained in the black powder, and has limitations in being harmful to the environment.

However, the method for manufacturing black powder according to the present invention can easily separate/remove the positive electrode collector by adding a predetermined organic solvent to the positive electrode scrap from which the positive electrode collector has been pulverized. In addition, the organic solvent added to the positive electrode scrap can dissolve the conductive material and the binder in the residue of the positive electrode scrap from which the positive electrode collector has been separated, i.e., the black powder, with high efficiency, thereby dissolving them from the black powder.

At this time, the organic solvent can be mixed with the positive electrode scrap and stirred at a predetermined temperature range. Specifically, the organic solvent can be mixed with the positive electrode scrap and stirred at a temperature of 150°C or lower, and more specifically, the organic solvent can be mixed with the positive electrode scrap and stirred at a temperature of 50°C to 150°C; 80°C to 150°C; 100°C to 150°C; 120°C to 150°C; 50°C to 120°C; 50°C to 100°C; 70°C to 130°C; or 85°C to 115°C.

In order to detach the positive electrode collector from the positive electrode scrap, the dissolution of the binder distributed at the interface between the positive electrode collector and the positive electrode active layer is essential. In addition, in order to reduce the content of non-metallic compounds such as conductive agents or binders in the positive electrode active layer remaining after the positive electrode collector is detached from the positive electrode scrap, i.e., the black powder, it is preferable to separate them with an organic solvent. Accordingly, the present invention can increase the molecular momentum of an organic solvent mixed with the positive electrode scrap in order to facilitate the dissolution of the conductive agent and binder from the black powder. Here, the molecular momentum of the organic solvent can be implemented by the speed or temperature conditions at which the mixture of the positive electrode scrap and the organic solvent is stirred.

Conventionally, methods such as sonication have been applied to separate the positive electrode current collector and the black powder. However, although the sonication has the advantage of being able to quickly dissolve the binder located at the interface between the positive electrode current collector and the positive electrode active layer, there is a problem in that it induces damage to the positive electrode current collector itself, causing impurities such as aluminum (Al) derived from the positive electrode current collector to significantly increase in the black powder. In addition, the eluted conductive agent and/or binder may undergo a side reaction on the surface of the black powder through the ultrasonic irradiation, thereby being fixed or having a form uniformly dispersed in an organic solvent. In this form, even if the black powder and the organic solvent are separated, the conductive agent and binder remain in the black powder in a significant amount, so there is a limitation that the content of the metal component included in the black powder is rather reduced.

However, the present invention can easily separate the positive electrode current collector from the positive electrode scrap by increasing the molecular momentum of the organic solvent itself mixed with the positive electrode scrap through stirring speed and/or temperature control, and can also remove the conductive material and binder from the black powder residue with high efficiency. To this end, the mixture of the positive electrode scrap and the organic solvent can be stirred within a predetermined temperature range.

In addition, the organic solvent may be a polar solvent having a boiling point (b.p.) higher than the temperature conditions at which stirring is performed, and capable of easily dissolving inorganic salts, acid bases, transition metal complexes, etc. For example, the organic solvent may include at least one of trimethyl phosphate (TMP), triethyl phosphate (TEP), dimethyl formamide (DMF), dimethyl acetamide (DMAc), and dimethyl sulfoxide (DMSO).

As an example, the organic solvent may be triethyl phosphate (TEP) or dimethyl sulfoxide (DMSO). The triethyl phosphate and dimethyl sulfoxide have relatively low toxicity compared to other organic solvents and have a low Hansen solubility parameter (Ra), making them suitable for dissolving a conductive material and/or binder present inside the black powder. Here, the Hansen solubility parameter (Ra) represents the distance between a binder molecule, such as polyvinylidene fluoride (PVdF), and a solvent molecule in a three-dimensional Hansen space.

In addition, the mixture of the positive electrode scrap and the organic solvent can be stirred at a predetermined speed for a predetermined time. Specifically, this step (S1) can be performed under conditions of 200 rpm to 1,000 rpm for 5 minutes to 100 minutes.

More specifically, the present step (S1) may be stirred for 5 minutes to 90 minutes; 5 minutes to 60 minutes; 5 minutes to 30 minutes; 5 minutes to 15 minutes; 10 minutes to 100 minutes; 30 minutes to 100 minutes; 60 minutes to 100 minutes; 10 minutes to 50 minutes; 30 minutes to 60 minutes; 70 minutes to 90 minutes; 15 minutes to 60 minutes; or 20 minutes to 40 minutes.

Additionally, the stirring can be performed at a speed of 200 rpm to 900 rpm; 200 rpm to 500 rpm; 200 rpm to 400 rpm; 500 rpm to 1,000 rpm; 700 rpm to 1,000 rpm; 400 rpm to 800 rpm; or 300 rpm to 700 rpm.

Furthermore, the positive electrode scrap and the organic solvent may be mixed at a predetermined ratio. For example, the positive electrode scrap may be mixed with 200 mL to 900 mL of the organic solvent per 100 g. More specifically, the positive electrode scrap may be mixed at a ratio of 200 mL to 800 mL; 200 mL to 600 mL; 200 mL to 400 mL; 450 mL to 900 mL; 600 mL to 900 mL; 300 mL to 700 mL; or 400 mL to 600 mL per 100 g.

The present invention enables the anode current collector included in the cathode scrap to be separated from the black powder more easily by stirring a mixture including the cathode scrap and an organic solvent so as to satisfy the conditions described above, and enables the conductive material and binder contained inside the black powder to be eluted with the organic solvent.

In addition, the method for manufacturing the black powder includes a step (S2) of filtering the previously stirred mixture to separate the positive electrode collector.

This step (S2) refers to the process of removing the cathode current collector detached from the cathode scrap through stirring with an organic solvent.

The above positive electrode collector can be separated through filtration, and the filtration can be performed using at least one of a filter and a filter having a condition that only the separated positive electrode collector cannot pass through.

The above-mentioned filtered positive electrode collector can be washed with the same component as the organic solvent included in the mixture during the filtration process, and can be collected separately and regenerated after filtration. Specifically, the regeneration of the positive electrode collector is performed by first collecting the positive electrode collector separated by filtration separately. Then, the collected positive electrode collector is placed in an organic solvent and stirred at a speed of 400 to 500 rpm at 150 to 250° C., and when the stirring is complete, it is irradiated with ultrasonic waves for 10 to 60 minutes while still placed in the organic solvent, and then washed, thereby being regenerated. At this time, the organic solvent used for placing and washing the positive electrode collector may be the same as the organic solvent mixed with the positive electrode scrap. In addition, the ultrasonic irradiation can be performed under conditions of a power of 0.5 to 16 kW and a frequency of 15 KHz to 50 KHz.

In addition, the method for manufacturing the black powder includes a step (S3) of obtaining black powder by separating an organic solvent containing a conductive material and a binder from a mixture from which the positive electrode collector is separated.

At this time, the method for separating the organic solvent containing the above-mentioned challenge agent and binder is not particularly limited, but may preferably be a method using a centrifugal separation method.

Since the organic solvent above has a form in which the binder is uniformly dissolved, it can be separated together with the binder at once through filtration or the like. However, in the case of the conductive material, since it has a form dispersed in the organic solvent, it is difficult to separate the conductive material through general filtration.

Accordingly, the present invention can separate the conductive material and binder in the black powder together with the organic solvent by centrifuging a mixture of black powder and an organic solvent and then separating the supernatant. Specifically, this step (S3) can be performed by the following process:

Step (S3-1) of centrifuging the mixture from which the positive electrode collector is separated;

A step (S3-2) of separating the organic solvent containing the conductive agent and binder by decanting the supernatant of the centrifuged mixture, and

Step (S3-3) of manufacturing black powder by filtering and washing the decanted residue of the supernatant.

In this step (S3), the supernatant of the centrifuged mixture is decanted to separate the residue (e.g., solid content), and the conductive material and binder remaining on the surface can be additionally removed through filtration and washing.

At this time, the washing can be performed twice or more, specifically 2 to 5 times, with the same component as the organic solvent separated from the mixture, and the amount of the organic solvent used during washing can be applied in an amount of 60 to 200 wt%, specifically 60 to 150 wt%, based on the weight of the black powder being washed.

Furthermore, the method for manufacturing black powder of the present invention may further include a step (S5) of additionally separating a conductive material included in the black powder obtained in step (S3) to further reduce the content of carbon-based compounds in the manufactured black powder.

At this time, the additional separation can be performed through a flotation selection method. The flotation selection method refers to a method of selection by utilizing the difference in the physicochemical properties of the particle surface. The method selectively attaches bubbles and/or droplets to the surface of the target particle by utilizing the significant difference in wettability of the particle surface, and then floats the particles to which the bubbles and/or droplets are attached, thereby selectively separating the particles. Conventional sedimentation separation methods utilizing the difference in density/specific gravity of the particles to be separated or solution layer separation methods using hydrophilic and hydrophobic solutions have the problem of low efficiency in separating trace amounts of conductive materials remaining in the black powder. In addition, since the boundaries of the heterogeneous materials to be separated are induced unclearly during the process, a considerable amount of solvent is required for their separation, and accordingly, there is a problem that the amount of waste generated is significantly large. However, the flotation selection method has the advantage of not only using a significantly small amount of solvent during the process, but also being able to highly efficiently separate conductive materials in the black powder by means of bubbles and/or droplets.

Here, the bubbles may be formed by distributing a floating additive mixed in a hydrophilic solvent to the outer surface of a predetermined air/gas, and may have a foam-like shape. In addition, the droplets may be formed by dispersing the floating additive itself in a hydrophilic solvent.

Accordingly, this step (S5) may include a step (S5-1) of mixing black powder and a floating additive in a hydrophilic solvent to float the conductive material in the black powder to the top of the solution, and a step (S5-2) of removing the conductive material floated to the top of the solution.

The black powder may include a metal and/or metal compound as a main component and a conductive material which is a carbon-based compound, wherein the metal and/or metal compound exhibits hydrophilicity while the carbon-based compound exhibits relatively hydrophobicity.

Accordingly, in this step (S5), black powder and a floating additive may be mixed in a hydrophilic solvent to generate bubbles and/or droplets inside the solution. The bubbles and/or droplets thus generated may be attached to the surface of a conductive material and float to the top of the solution (S5-1). Specifically, black powder and a floating additive may be mixed in a hydrophilic solvent and stirred for a predetermined period of time so that the generated bubbles and/or droplets are attached to the hydrophobic surface of the conductive material. Thereafter, when the stirring is finished, the conductive material may be floated to the top of the solution by the bubbles and/or droplets attached to the surface. By capturing the floating bubbles and/or droplets at the top of the solution (S5-2), the conductive material remaining inside the black powder may be additionally removed.

Here, the amount and/or efficiency of the conductive agent attached to the bubbles may vary depending on the content of the hydrophilic solvent and the floating additive mixed with the black powder, the stirring speed for bubble generation and floating, etc.

Accordingly, in order to further reduce the content of the conductive agent remaining in the black powder, the content of the black powder and the floating additive mixed in the hydrophilic solvent, the stirring speed, and the stirring time can be adjusted to satisfy predetermined conditions.

As an example, the black powder may be mixed in an amount of 0.1 wt% to 50 wt% based on the weight of the hydrophilic solvent, and the floating additive may be mixed in an amount of 0.1 wt% to 40 wt% based on the volume of the hydrophilic solvent.

Specifically, the black powder is present in an amount of 0.1 wt% to 40 wt%, 0.1 wt% to 30 wt%, 0.1 wt% to 25 wt%, 0.1 wt% to 20 wt%, 0.1 wt% to 15 wt%, 0.1 wt% to 10 wt%, 0.1 wt% to 9 wt%, 0.1 wt% to 5 wt%, 0.5 wt% to 10 wt%, 1 wt% to 10 wt%, 5 wt% to 20 wt%, 10 wt% to 30 wt%, 20 wt% to 40 wt%, 30 wt% to 40 wt%, 11 wt% to 19 wt%, 1 wt% to 5 wt%, 1 wt% to 3 wt%, 0.5 wt% to 5 wt%, 0.5 wt% to 3 wt%, It can be mixed at 0.1 wt% to 3 wt%, or 0.1 wt% to 1 wt%.

In addition, the floating additive can be mixed in an amount of 0.1 vol% to 30 vol%, 0.1 vol% to 20 vol%, 0.1 vol% to 10 vol%, 0.1 vol% to 9 vol%, 2 vol% to 9 vol%, 4 vol% to 15 vol%, 10 vol% to 20 vol%, 10 vol% to 30 vol%, 20 vol% to 40 vol%, 25 vol% to 35 vol%, 15 vol% to 25 vol%, 1 vol% to 6 vol%, 0.1 vol% to 2 vol%, or 2 vol% to 7 vol%, based on the volume of the hydrophilic solvent.

As another example, stirring of a mixed solution containing black powder, a hydrophilic solvent, and a floating additive can be performed at a speed of 500 rpm to 5,000 rpm for 1 minute to 100 minutes.

Specifically, the stirring of the mixed solution can be performed for 1 minute to 90 minutes; 1 minute to 80 minutes; 1 minute to 60 minutes; 1 minute to 40 minutes; 1 minute to 30 minutes; 1 minute to 20 minutes; 1 minute to 15 minutes; 1 minute to 10 minutes; 1 minute to 5 minutes; 2 minutes to 7 minutes; 5 minutes to 10 minutes; 10 minutes to 30 minutes; 20 minutes to 60 minutes; 50 minutes to 100 minutes; 5 minutes to 15 minutes; or 1 minute to 9 minutes.

Additionally, the stirring of the mixed solution can be performed at a speed of 500 rpm to 4,000 rpm; 500 rpm to 3,000 rpm; 500 rpm to 2,500 rpm; 500 rpm to 2,000 rpm; 500 rpm to 1,500 rpm; 500 rpm to 1,000 rpm; 2,500 rpm to 5,000 rpm; 3,000 rpm to 5,000 rpm; 2,000 rpm to 4,000 rpm; 1,000 rpm to 3,000 rpm; 700 rpm to 1,500 rpm; or 500 rpm to 1.80 rpm.

The present invention can effectively separate a small amount of conductive material remaining inside black powder during flotation with less energy by controlling the content ratio of each component and/or the stirring conditions as described above.

Meanwhile, the hydrophilic solvent may include at least one of water and C _1-4 alkyl alcohols such as methanol and ethanol. The hydrophilic solvent not only has high wettability for the black powder, but also has the characteristic of being an environmentally friendly solvent.

In addition, the buoyant additive can form bubbles and/or droplets in a hydrophilic solvent, while having a function of attaching a conductive material having hydrophobicity to the bubble surface. The buoyant additive can include at least one of mineral oil, trimethyl phosphate (TMP), and triethyl phosphate (TEP). The buoyant additives have relatively low affinity for hydrophilic solvents compared to formamide (DMF), dimethyl acetamide (DMAc), dimethyl sulfoxide (DMSO), and the like, and thus can easily induce formation of bubbles and/or droplets within the hydrophilic solvent during stirring. In addition, since the buoyant additives have high affinity for the conductive material, the conductive material present in the black powder can be attached to the bubbles with high efficiency.

For example, trimethyl phosphate (TMP) and/or triethyl phosphate (TEP) as the above-mentioned floating additives can be mixed with a hydrophilic solvent to form microbubbles, and the microbubbles thus formed can easily attach to the surface of the conductive material and float the conductive material to the top of the solution.

In addition, the mineral oil can form fine droplets when mixed alone in a hydrophilic solvent and form an emulsion with the hydrophilic solvent. Since the droplets have hydrophobicity and high affinity for the conductive material, they can be attached to the surface of the conductive material and floated to the top of the solution. In addition, the mineral oil can be mixed with a hydrophilic solvent to form fine bubbles when used in combination with trimethyl phosphate (TMP) and/or triethyl phosphate (TEP). The fine bubbles formed at this time can easily be attached to the surface of the conductive material and float the conductive material to the top of the solution.

Meanwhile, the bubbles and/or droplets floating to the top of the mixed solution may have a structure in which the outside is surrounded by a floating additive or may be composed of a floating additive itself, and may have a form in which a conductive agent remaining inside the black powder is attached by the floating additive. Accordingly, the mixed solution from which the bubbles and/or droplets are removed may be composed of the black powder from which the conductive agent is removed and a hydrophilic solvent.

The mixed solution from which bubbles and/or droplets have been removed can be used to separate the hydrophilic solvent through distillation or other methods, thereby producing a black powder having a significantly lower content of carbon compounds.

The black powder obtained in this way may have a significantly low content of the conductive agent and binder, and when analyzing the components, the positive electrode active material contained in the positive electrode may be detected as the main component.

As an example, the black powder may have a carbon (C) element content of less than 5 wt% when analyzed by component analysis using X-ray photoelectron spectroscopy (XPS), and specifically, may have a content of 0.01 to 5 wt%, 0.01 to 3 wt%, 0.01 to 1 wt%, 0.5 to 3 wt%, 1 to 4 wt%, or 3 to 5 wt%.

Furthermore, the method for manufacturing the black powder includes a step (S4) of separating the conductive agent and the binder from the organic solvent separated from the black powder and recovering the organic solvent. This step (S4) refers to a process of purifying the separated organic solvent.

Here, the present step (S4) may be applied without particular limitation as long as it is a method capable of separating the organic solvent from the conductive agent and the binder, but may preferably be performed through reduced pressure distillation. The reduced pressure distillation may selectively volatilize the organic solvent introduced into the reactor by lowering the pressure inside the reactor to a vacuum or close to a vacuum and controlling the temperature to the boiling point (b.p.) of the organic solvent or a temperature slightly lower than the boiling point (b.p.). The organic solvent thus volatilized may be condensed by a cooler located at the top of the reactor and recovered again, and the recovered organic solvent may have a high purity of 90% or more, for example, 95% or more, 98% or more, or 99% or more, that does not include the conductive agent or the binder.

Since the organic solvent has high purity, it can be reused in the process of manufacturing the black powder according to the present invention. Specifically, the recovered organic solvent can be used in the process of producing a mixture of positive electrode scraps in step (S1) and can be used in the process of washing the positive electrode current collector separated in step (S2). In addition, the recovered organic solvent can be used in the filtering and/or washing of the black powder separated from the organic solvent in step (S3).

The present invention is not only environmentally friendly because it can significantly reduce the amount of waste generated in the process of manufacturing black powder by reusing recovered organic solvent, but also has economic advantages because it consumes less raw materials used in the process.

The method for manufacturing black powder according to the present invention can easily separate and remove the positive electrode current collector from the positive electrode scrap by having the above-described configuration, and can efficiently separate and remove the positive electrode conductive material and binder from the black powder from which the positive electrode current collector has been removed, thereby manufacturing high-purity black powder. In addition, the manufacturing method has an environmentally friendly advantage because the organic solvent used during the process is reused.

Black Powder Manufacturing System

Furthermore, in an embodiment of the present invention,

A system for recovering black powder from positive electrode scrap derived from waste batteries.

A stirring section that stirs a mixture of positive electrode scrap and an organic solvent to detach the positive electrode collector contained in the positive electrode scrap and elute the conductive material and binder contained inside the black powder into the organic solvent.

A filter unit that is fluidly connected to the above stirring unit and receives a stirred mixture, and filters out the positive electrode current collector from the provided mixture;

A separation unit that is fluidly connected to the above filter unit and receives a separated mixture from the positive electrode collector, and separates an organic solvent containing a conductive agent and a binder from the provided mixture to obtain a black powder; and

A black powder manufacturing system is provided, which includes a distillation unit for separating a conductive agent and a binder from an organic solvent separated in the above separation unit and recovering the organic solvent.

The above black powder manufacturing system is for performing the black powder manufacturing method of the present invention described above.

Specifically, the black powder manufacturing system can desorb the positive electrode current collector from the positive electrode scrap and elute the conductive material and binder from the black powder residue into the organic solvent by stirring a mixture of positive electrode scrap derived from a spent battery and a predetermined organic solvent in a stirring unit at a temperature of 150°C or lower.

At this time, the stirring unit may include a dispersion blade mixer, a stirring mixer, a screw mixer, a conical screw mixer, a planetary stirring mixer, an air jet mixer, a high shearing mixer, etc. for stirring the mixture.

In addition, the stirring unit may include a temperature control device to provide appropriate heat energy to the mixture being stirred. The temperature control device is arranged outside the stirring unit to control the temperature of the outer surface of the stirring unit, thereby providing heat energy to the mixture being stirred inside the stirring unit. In addition, the temperature control device is electrically connected to a temperature measuring device located inside the stirring unit to control the temperature of the outer surface of the stirring unit according to the temperature inside the stirring unit.

In addition, the above black powder manufacturing system can remove the cathode current collector detached from the cathode scrap by transferring the mixture stirred in the stirring unit to the filter unit and filtering it. At this time, the filter unit can be applied without particular limitation as long as it has a form capable of filtering out the cathode current collector.

For example, the filter may include a filter or a strainer for filtering out the positive electrode current collector at the bottom, and the filter or strainer may have holes having a size ratio of 40% to 80% based on the average size of the positive electrode current collector included in the positive electrode scrap to allow passage of materials other than the positive electrode scrap.

In addition, the above black powder manufacturing system can manufacture black powder by moving a mixture from which a positive electrode collector has been removed to a separation unit and then separating an organic solvent containing a conductive material and a binder.

At this time, the separation unit may include a centrifuge to separate the black powder and the organic solvent.

Since the organic solvent of the mixture provided in the above filtering unit has a form in which the binder is uniformly dissolved, it can be separated together with the binder through filtration or the like. However, in the case of the conductive agent, since it has a form dispersed in the organic solvent, it is difficult to separate the conductive agent when separating the organic solvent by general filtration. However, the present invention can separate the conductive agent and binder in the black powder together with the organic solvent by centrifuging the mixture of the black powder and the organic solvent using a centrifuge and then separating the supernatant.

For this purpose, the separation unit may include a centrifuge, and the upper part of the centrifuge may be fluidly connected so that the supernatant of the centrifuged mixture can be separated and provided to the distillation unit.

In addition, the separation unit may include a filter that supports and filters the black powder at the bottom to increase the purity of the mixture, i.e., the black powder, remaining after the supernatant is separated, and allows organic solvents remaining in the black powder to pass therethrough.

The above separation unit may have a filter at the bottom so that the black powder filtered inside may be washed with an organic solvent, thereby further improving the purity of the black powder. Here, a pipe may be introduced at the bottom of the separation unit, specifically, at the bottom of the filter, so that the residual organic solvent and washing liquid passing through the filter may flow to the distillation unit.

The above black powder manufacturing system may further include means for further removing a conductive material from the black powder obtained from the separation unit in order to further reduce the content of a carbon-based compound, specifically, a conductive material, present in the black powder.

For example, the black powder manufacturing system may further include a flotation separation unit for additionally removing a conductive material from the black powder.

The above flotation separation unit may be fluidly connected to the separation unit and may receive the black powder obtained from the separation unit, and may provide a space in which the provided black powder, a hydrophilic solvent, and a flotation additive are mixed to generate bubbles. Specifically, the flotation separation unit may include a reaction tank in which the black powder provided from the separation unit, a hydrophilic solvent, and a flotation additive are mixed.

The above reactor may include a stirring means such as a dispersion blade mixer, a stirring mixer, a screw mixer, a conical screw mixer, a planetary stirring mixer, an air jet mixer, a high shearing mixer, etc., on the lower surface to mix the black powder, the hydrophilic solvent, and the floating additive.

In addition, the above reaction tank may include a bubble catcher at the top to remove bubbles generated after stirring the mixed solution containing the black powder, hydrophilic solvent, and floating additive and floating to the top of the mixed solution. At this time, the bubble catcher may be applied without particular limitation as long as it has a form capable of capturing bubbles floating on the solution.

In addition, the above-mentioned flotation separation unit may further include a distillation means for removing the solvent of the mixed solution remaining in the reaction tank after capturing the bubbles, i.e., the hydrophilic solvent.

In addition, the black powder manufacturing system can purify the organic solvent provided from the separation unit including a distillation unit. Specifically, the distillation unit can recover a high-purity organic solvent from which the conductive agent and binder are removed from the organic solvent provided from the separation unit including a reduced pressure distillation device.

At this time, the reduced pressure distillation device may include a reactor into which an organic solvent provided from a separation unit is injected, a vacuum pump located at the top of the reactor to lower the internal pressure to vacuum or close to vacuum, a heater located at the bottom of the reactor to provide heat below the boiling point (b.p.) of the organic solvent inside the reactor, a cooler located at the top of the reactor to cool and condense the organic solvent that volatilizes, and an organic solvent storage unit that captures and stores the organic solvent condensed in the cooler.

In addition, the organic solvent storage unit of the above-described reduced pressure distillation device can store a high-purity organic solvent, and can be fluidly connected to at least one of the stirring unit, filtering unit, and separation unit of the black powder manufacturing system to supply the recovered organic solvent.

The organic solvent provided in this manner has high purity and can therefore be reused in the process of manufacturing black powder according to the present invention. The black powder manufacturing system of the present invention is not only environmentally friendly because it can significantly reduce the amount of waste generated in the process of manufacturing black powder by reusing the organic solvent, but also has an economic advantage because it consumes less raw materials used in the process.

In addition, the operating conditions of the specific system for manufacturing black powder are identical to the composition of the method for manufacturing black powder described above, so a detailed description is omitted.

Furthermore, the manufacturing system is a closed-loop system in which all processes are performed within a single closed space. That is, when the positive electrode scrap is provided to the system, the manufacturing system automatically goes through each step according to the set value without separate operation by the user, and finally discharges the positive electrode current collector separated from the generated black powder. Therefore, the manufacturing system of the present invention has the advantage of being simple in both the process actually performed and the process that the user must operate.

The system for manufacturing black powder according to the present invention can easily separate and remove the positive electrode current collector from the positive electrode scrap by having the above-described configuration, and can highly efficiently separate and remove the positive electrode conductive material and binder from the black powder from which the positive electrode current collector has been removed, thereby manufacturing high-purity black powder. In addition, the manufacturing system has an environmentally friendly advantage because the organic solvent used during the process is reused.

Hereinafter, the present invention will be described in more detail through examples and experimental examples.

However, the following examples and experimental examples are only intended to illustrate the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

Examples and Comparative Examples. Method for Manufacturing Black Powder

A lithium secondary battery whose lifespan has expired and containing LiNi _0.6 Co _0.2 Mn _0.2 O ₂ as a cathode active material was disassembled to prepare a cathode. The prepared cathode was pulverized to prepare cathode scrap (average size: approximately 10–20 μm).

Thereafter, 100 g of the prepared positive electrode scrap and an organic solvent were introduced into the stirring unit of the black powder manufacturing system, and the introduced positive electrode scrap and the organic solvent were stirred or ultrasonically irradiated for 30 minutes to detach the positive electrode collector from the positive electrode scrap, and the conductive material and binder included inside the black powder were eluted (S1) into the organic solvent. Here, ① the type of organic solvent mixed with the positive electrode scrap, ② the mixing amount (specifically, the mixing amount per 100 g of positive electrode scrap), and ③ the mixing method were controlled as shown in Table 1 below. In addition, ④ the internal temperature of the reactor during mixing was controlled by a temperature control device mounted on the outer lower part of the reactor, as shown in Table 1. In addition, when stirring was performed during mixing, a stirring mixer was used at a speed of 400±50 rpm; and when ultrasonic irradiation was performed, a power of 5 to 10 kW and a frequency of 5 to 10 KHz were performed.

When the mixing in the stirring unit was completed, the mixture of the positive electrode scrap and the organic solvent was delivered to the filtration unit fluidly connected to the stirring unit. The mixture delivered to the filtration unit passed through the filter (average hole size: approximately 5 to 10 μm) mounted at the bottom of the filtration unit, and through this process, the positive electrode collector separated from the positive electrode scrap was filtered out and removed (S2). The filtered positive electrode collector was dried in a vacuum oven at 150°C, and the weight of the dried positive electrode collector was measured to calculate the weight (A) of the component in the positive electrode scrap excluding the positive electrode collector.

A mixture excluding the positive electrode collector (specifically, black powder, conductive agent, binder, and organic solvent) was delivered to a centrifuge in a separation unit fluidly connected to the lower part of the filtration unit. The mixture delivered to the centrifuge was centrifuged at 500 to 1,000 rpm for 10 to 30 minutes. When centrifugation was completed, the supernatant of the centrifuged mixture was delivered to the distillation unit through a pipe fluidly connected to the upper part of the centrifuge and separated. In addition, the residue remaining inside the centrifuge was filtered and washed with a filter mounted at the lower part of the centrifuge. At this time, the washing of the residue was performed 2 to 3 times using the same organic solvent as the organic solvent included in the mixture at 80 to 120 wt% based on the weight of the residue. The washing liquid from which the residue was washed passed through the filter and delivered to the distillation unit through a pipe fluidly connected to the lower part of the filter.

The washed residue was collected and dried in a vacuum oven at 150°C to produce black powder (S3).

The weight (B) of the manufactured i) black powder was measured, and the recovery rate of the black powder was calculated using the weight (A) of the components excluding the positive electrode collector from the positive electrode scrap measured previously. As a result, it was confirmed that the black powder of the example had a high recovery rate of about 70% or more, while the black powder of the comparative example had a lower recovery rate than this.

In addition, ii) X-ray photoelectron spectroscopy (XPS) was performed on the black powder to analyze the components contained in the black powder. At this time, the X-ray photoelectron spectroscopy (XPS) was performed using Monochromated-Al-Kα (1486.6 eV) as an X-ray light source with an X-ray irradiation diameter of 400 ㎛, the energy of the Ar sputtering gun was 1,000 eV, and the etching time and speed were 3,000 seconds and 0.1±0.01 nm/s, respectively.

The purity of the manufactured ⑤ black powder and ⑥ carbon element content were calculated by calculating the element ratios of components other than the metals that constitute the cathode active material, namely lithium (Li), nickel (Ni), cobalt (Co), manganese (Mn), and oxygen (O), among the analyzed components. The results are shown in Table 1 below.

Meanwhile, the conductive agent was additionally removed from the black powder obtained in Example 2. Specifically, the black powder obtained in Example 2 was delivered to the reaction tank of the flotation separation unit, water was added to the reaction tank, and the mixture was stirred with a stirring mixer for 5±1 minutes. Thereafter, a buoyant additive was added to the reaction tank, and the mixture was additionally stirred at a speed of 1,000±100 rpm with a stirring mixer for 5±1 minutes to generate bubbles and/or droplets in the mixed solution, while the conductive agent inside the black powder was attached to the surface of the generated bubbles and/or droplets to float to the top of the solution (S5-1). At this time, a) the mixing amount of the black powder and the buoyant additive based on the total weight of the hydrophilic solvent and b) the type of the buoyant additive were controlled as shown in Table 2 below.

When stirring was completed, the air bubbles and/or droplets floating to the top of the mixed solution were removed to remove the conductive agent (S5-2). At this time, in order to reduce the residual amount of the air bubbles and/or droplets and the conductive agent attached thereto, water, a hydrophilic solvent, was added to the mixed solution during removal to remove the air bubbles and/or droplets.

A black powder was prepared by removing the hydrophilic solvent by distilling the mixed solution under reduced pressure from which the challenge agent was removed.

The recovery rate of the black powder manufactured in the same manner as previously performed, ⑦ the purity of the black powder, and ⑧ the carbon element content were calculated. The results are shown in Table 2 below.

Separately from this, the organic solvents previously delivered to the distillation unit were purified and recovered by the reduced pressure distillation device of the distillation unit, and the recovered organic solvents were reused (S4) in the process of mixing with the anode scrap. Specifically, the organic solvents were delivered to the reactor of the reduced pressure distillation device. Thereafter, heat of 110 to 180° C. was applied to the reactor while the internal pressure was lowered by the vacuum pump located at the top of the reactor, thereby performing reduced pressure distillation of the organic solvents. The distilled organic solvents were cooled and condensed by the cooler located at the top of the reactor, and the condensed organic solvents were delivered to the organic solvent storage unit and temporarily stored. The temporarily stored organic solvents were delivered to the stirring unit through a pipe fluidly connected between the organic solvent storage unit and the stirring unit for mixing with the anode scrap.

Organic solvent mix Black powder ① Type ② Mixing amount ③ Method ④ Internal temperature ⑤ Purity ⑥ Carbon content Example 1 DMSO 500 mL Stirring 100±10℃ About 96% About 1.1 wt% Example 2 TEP 500 mL Stirring 100±10℃ About 97% About 0.8 wt% Example 3 TEP 50 mL Stirring 100±10℃ About 91% About 1.9 wt% Example 4 TEP 2,000 mL Stirring 100±10℃ About 88% About 3.1 wt% Example 5 TEP 500 mL Stirring 20±10℃ About 87% About 3.6 wt% Comparative Example 1 TEP 500 mL Stirring 180±10℃ About 86% About 3.3 wt% Comparative Example 2 TEP 500 mL Ultrasonic examination 100±10℃ About 82% About 4.8 wt% Comparative Example 3 NMP 500 mL Stirring 100±10℃ About 84% About 4.1 wt% Comparative Example 4 water 500 mL Stirring 100±10℃ About 81% About 5.1 wt% DMSO: Dimethyl sulfoxide
TEP: Triethyl Phosphate
NMP: N-Methylpyrrolidone

Black powder mixing amount
[Based on total weight of water] Floating additives Final Black Powder Mixed amount
[Based on total volume of water] type ⑦ Purity ⑧ Carbon content Example 2-a 0.05 wt% 0.5% by volume TEP About 97.1% About 0.7 wt% Example 2-b 30 wt% 0.5% by volume TEP About 98.0% About 0.4 wt% Example 2-c 60 wt% 0.5% by volume TEP About 96.9% About 0.8 wt% Example 2-d 0.5 wt% 0.05% by volume TEP About 97.1% About 0.7 wt% Example 2-e 0.5 wt% 0.5% by volume TEP About 98.8% About 0.1 wt% Example 2-f 0.5 wt% 10% by volume TEP About 98.4% About 0.2 wt% Example 2-g 0.5 wt% 45% by volume TEP About 96.6% About 0.6 wt% Example 2-h 0.5 wt% 0.6% by volume Mineral oil About 98.3% About 0.3 wt% Example 2-i 0.5 wt% 30% by volume Mineral oil About 98.5% About 0.1 wt% Example 2-j 0.5 wt% 40% by volume Mineral oil About 97.2% About 0.7 wt%

As shown in Table 1 and Table 2 above, it can be seen that the method for manufacturing black powder according to the present invention can obtain high-purity black powder from positive electrode scrap with a high recovery rate.

From these results, it can be seen that the method and system for manufacturing black powder according to the present invention can not only manufacture high-purity black powder with high efficiency, but is also environmentally friendly because the organic solvent used during the process is reused.

Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art or having ordinary knowledge in the art that various modifications and changes may be made to the present invention without departing from the technical scope of the present invention as set forth in the claims below.

Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the scope of the patent claims.

Claims (13)

A method for producing black powder from positive electrode scrap derived from waste batteries, Step (S1) of stirring a mixture of positive electrode scrap and an organic solvent at a temperature of 150°C or lower to detach the positive electrode collector contained in the positive electrode scrap and to elute the conductive material and binder contained inside the black powder with an organic solvent. Step (S2) of filtering the above mixture to separate the positive electrode collector; Step (S3) of obtaining a black powder by separating an organic solvent containing a conductive agent and a binder from the above mixture from which the positive electrode collector is separated, and A step (S4) of separating the conductive material and the binder from the organic solvent containing the conductive material and the binder and recovering the organic solvent; The organic solvent recovered in the above step (S4) is reused in at least one of the steps (S1) to (S3); A method for producing black powder, wherein the organic solvent comprises at least one of trimethyl phosphate (TMP), triethyl phosphate (TEP), dimethyl formamide (DMF), dimethyl acetamide (DMAc), and dimethyl sulfoxide (DMSO). In the first paragraph, A method for producing black powder in which the above cathode scrap is mixed with 200 mL to 900 mL of an organic solvent per 100 g. In the first paragraph, The above step (S1) is a method for manufacturing black powder, which is performed under conditions of 200 rpm to 1,000 rpm for 5 to 100 minutes. In the first paragraph, The step (S3) of obtaining the above black powder is: Step (S3-1) of centrifuging the mixture from which the positive electrode collector is separated; A step (S3-2) of separating an organic solvent containing a conductive agent and a binder by decanting the supernatant of the centrifuged mixture; It includes a step (S3-3) of filtering and washing the decanted residue to produce black powder. A method for producing black powder, wherein washing of the residue is performed twice or more repeatedly with the same organic solvent as the organic solvent of the mixture. In the first paragraph, After the step (S3) of obtaining the above black powder, a step (S5) of further separating the conductive material included in the obtained black powder is further included. A method for producing black powder, wherein the above additional separation is performed through a flotation selection method. In paragraph 5, The step (S5) of further separating the above challenge material is A step (S5-1) of mixing black powder and a floating additive in a hydrophilic solvent to float the conductive agent in the black powder to the top of the solution, and A method for manufacturing black powder, comprising a step (S5-2) of removing a conductive agent floating on the top of a solution. In paragraph 5, The above black powder is mixed in an amount of 0.1 wt% to 50 wt% based on the weight of the hydrophilic solvent, A method for producing black powder, wherein the above floating additive is mixed in an amount of 0.1 to 40 volume% based on the volume of the hydrophilic solvent. In paragraph 5, The above hydrophilic solvent comprises water and at least one of C _{1 to C 4} alkyl alcohols, A method for producing black powder, wherein the above floating additive comprises at least one of mineral oil, trimethyl phosphate (TMP), and triethyl phosphate (TEP). In the first paragraph, A method for producing black powder, wherein the step (S4) of recovering the organic solvent is performed by distilling the organic solvent containing the conductive agent and the binder under reduced pressure. In the first paragraph, A method for manufacturing black powder, characterized in that the manufactured black powder has a carbon element content of less than 5 wt% when analyzed by components. In a system for manufacturing black powder from positive electrode scrap derived from waste batteries, A stirring section that stirs a mixture of positive electrode scrap and an organic solvent to detach the positive electrode collector contained in the positive electrode scrap and elute the conductive material and binder contained inside the black powder into the organic solvent. A filter unit that is fluidly connected to the above stirring unit and receives a stirred mixture, and filters out the positive electrode current collector from the provided mixture; A separation unit that is fluidly connected to the above filter unit and receives a separated mixture from the positive electrode collector, and separates an organic solvent containing a conductive agent and a binder from the provided mixture to obtain a black powder; and A distillation unit is included for separating the conductive agent and binder from the organic solvent separated in the above separation unit and recovering the organic solvent; The organic solvent recovered from the distillation unit is supplied to at least one of the stirring unit, the filtration unit, and the separation unit and reused; A black powder manufacturing system wherein the organic solvent comprises at least one of trimethyl phosphate (TMP), triethyl phosphate (TEP), dimethyl formamide (DMF), dimethyl acetamide (DMAc), and dimethyl sulfoxide (DMSO). In Article 11, The above separation unit is a black powder manufacturing system including a centrifuge. In Article 11, The above black powder manufacturing system is a black powder manufacturing system further including a flotation separation unit that is fluidly connected to a separation unit to receive black powder and performs flotation separation to further remove a conductive material from the provided black powder.

Images