KR102132120B1 - A recycling method for the spent lithium ion secondary battery using carbon dioxide - Google Patents

Abstract

The present invention establishes an optimization process for completely recycling spent lithium-ion secondary batteries and scraps. In particular, using, as raw materials, spent lithium-ion secondary batteries or scraps produced during the manufacturing process of lithium-ion secondary batteries, the optimization process enables the following materials to be recovered through a series of processes: cathode materials including valuable metals including manganese, cobalt, and nickel; anode materials including graphite; battery materials including aluminum, copper, and iron; electrolytes; lithium hydroxide, which is an electric vehicle battery material; and lithium carbonate, which is a battery material for regular portable IT devices. In addition, by utilizing carbon dioxide in an electrolyte recovery process, a valuable metal recovery process, and a lithium synthesis process during the recycling process, the process of the present invention can reduce a large amount of carbon dioxide, thereby providing an environmentally friendly effect.

Description

Recycling method of waste lithium ion secondary battery using carbon dioxide{A RECYCLING METHOD FOR THE SPENT LITHIUM ION SECONDARY BATTERY USING CARBON DIOXIDE}

The present invention relates to a method for recycling a waste lithium ion secondary battery using carbon dioxide.

Today, lithium-ion secondary batteries are used not only in portable IT devices such as mobile phones and laptops, but also in various fields such as electric vehicles and energy storage devices (ESS), and the market is also expanding. Lithium, which is one of the core raw materials included in lithium ion secondary batteries, is a strategic metal resource, and worldwide lithium reserves are known to be 13 million tons. In particular, lithium is a metal that has fierce competition in terms of economy and scarcity, as resources are concentrated in some South American countries.

In addition, the positive electrode material, which is one of the essential components of the lithium ion secondary battery, is widely used as a positive electrode active material, and valuable metal oxides such as nickel, manganese, and cobalt. In Korea, the situation is that all of these expensive valuable metals depend on imports. .

On the other hand, as the use of lithium ion secondary batteries has been expanded, the treatment of spent lithium ion secondary batteries that have already been used is a problem, and the treatment of scraps, etc. that occur during the process of manufacturing lithium ion secondary batteries is also a problem. , Research on how to recover lithium or valuable metals that are discarded as wastes and turn them into resources has been actively conducted.

On the other hand, Korean Patent Publication No. 10-2011-0117024 (hereinafter referred to as'prior art') discloses a method for recovering valuable metals from a waste cathode material, but according to such prior art, certain valuable metals are recovered It has the disadvantage that it is difficult to fully recover the remaining negative electrode material, separator, and electrolyte contained in the waste battery or scrap, and it is difficult to completely recover all kinds of valuable metals in a series of processes, and furthermore, the waste lithium secondary battery There was a problem in that secondary wastes were generated because it was difficult to recycle resources completely.

On the other hand, the biggest environmental issue in the 21st century is climate change due to an increase in the concentration of greenhouse gases in the atmosphere, which is recognized as a problem of human survival. In particular, carbon dioxide is a problem because it causes a greenhouse effect as a main element of greenhouse gas, melting the glaciers of the earth, and increasing the average temperature of the earth.

Accordingly, the present inventor consumes a large amount of carbon dioxide in the air, and uses scrap generated during the manufacturing process of a waste lithium-ion secondary battery or lithium-ion secondary battery as a raw material, through a series of processes, a cathode material including a valuable metal, and a cathode including graphite. By recovering battery materials including ash, aluminum, copper, and iron, lithium hydroxide, which is an electric and battery material for electric vehicles, and lithium carbonate, which is a battery material for general portable IT devices, waste lithium ion secondary batteries and scraps are recycled at the same time, Optimization and eco-friendly process to reduce carbon dioxide in large quantities was established and the present invention was completed.

The present invention has been devised to solve the problems of the prior art, and scraps generated during the manufacturing process of a waste lithium-ion secondary battery or lithium-ion secondary battery as raw materials, oil prices including manganese, cobalt and nickel through a series of processes By recovering the cathode material including metal, anode material including graphite, battery materials including aluminum, copper and iron, electrolyte and lithium hydroxide, which is an electric vehicle battery material, and lithium carbonate, which is a battery material of a typical portable IT device, waste lithium ion secondary It was intended to establish and provide an optimization process for recycling batteries and scraps without leaving.

In addition, in the recycling process, carbon dioxide is used in an electrolyte recovery process, a valuable metal recovery process, and a lithium synthesis process, thereby reducing carbon dioxide in large quantities and establishing an environmentally friendly process to provide it.

In addition, the technical problem to be solved by the present invention is not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly apparent to those skilled in the art from the following description. Will be understandable.

In the present specification, a) separating and recovering the positive electrode material, the negative electrode material, the separator and the electrolyte from the waste lithium ion secondary battery or scrap, and then mechanically pretreating the positive electrode material and the negative electrode material to obtain a pulverized material; b) subjecting the separation membrane recovered in step a to supercritical carbon dioxide extraction; c) separating the graphite by pulverizing the pulverized product obtained in step a using an Air Jet Sieve; d) acid leaching by adding an acid solution to the pulverized product obtained in step c; e) extracting and recovering at least one valuable metal selected from the group consisting of manganese, cobalt and nickel from the leach obtained in step d; f) after step e, extracting lithium hydroxide by adding a hydroxide to the obtained lithium acid solution; g) after step f, adding hydrogen peroxide to the obtained lithium hydroxide to prepare a lithium peroxide solution; And h) after step g, adding a carbon dioxide to the obtained lithium peroxide solution to prepare a lithium carbonate solution; It provides a recycling method of a waste lithium ion secondary battery comprising a.

According to the recycling method of a waste lithium ion secondary battery according to an embodiment of the present invention, a scrap material generated during a manufacturing process of a waste lithium ion secondary battery or a lithium ion secondary battery is used as a raw material, and a cathode material including valuable metals through a series of processes By recovering the negative electrode material including graphite, the battery material including aluminum, copper and iron, the electrolyte, and lithium hydroxide, which is an electric vehicle battery material, and lithium carbonate, which is a battery material of a general portable IT device, it leaves a waste lithium ion secondary battery and scrap Without recycling.

In addition, according to the recycling method of a waste lithium ion secondary battery according to an embodiment of the present invention, carbon dioxide is used in an electrolyte recovery process, a valuable metal recovery process, and a lithium synthesis process, thereby reducing carbon dioxide in large quantities and establishing an environmentally friendly process. This is possible.

1 is a flowchart of a method for recycling a waste lithium ion secondary battery according to an embodiment of the present invention.
2 is a flow chart of a method of recycling a waste lithium ion secondary battery according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present description, descriptions of already known functions or configurations will be omitted to clarify the gist of the present description.

The recycling method of the waste lithium ion secondary battery according to the specific embodiment of the present invention will be described in more detail below.

As described above, the recycling method of a waste lithium ion secondary battery according to an embodiment of the present invention, a) after the separation and recovery of the positive electrode material, the negative electrode material, the separator and the electrolyte from the waste lithium ion secondary battery or scrap, the positive electrode material and Step of mechanically pre-treating the negative electrode material to obtain a pulverized material; b) subjecting the separation membrane recovered in step a to supercritical carbon dioxide extraction; c) separating the graphite by pulverizing the pulverized product obtained in step a using an Air Jet Sieve; d) acid leaching by adding an acid solution to the pulverized product obtained in step c; e) extracting and recovering at least one valuable metal selected from the group consisting of manganese, cobalt and nickel from the leach obtained in step d; f) after step e, extracting lithium hydroxide by adding a hydroxide to the obtained lithium acid solution; g) after step f, adding hydrogen peroxide to the obtained lithium hydroxide to prepare a lithium peroxide solution; And h) after step g, adding a carbon dioxide to the obtained lithium peroxide solution to prepare a lithium carbonate solution; It may include.

The present inventors, when using a scrap generated during the process of manufacturing a discharged waste lithium ion secondary battery or a lithium ion secondary battery as a raw material, when a specific process is arranged in time series and reacted under specific conditions, lithium and an expensive valuable metal are Manganese, cobalt and nickel can be fully recovered, negative electrode materials including graphite, battery materials including aluminum, copper and iron, lithium hydroxide as an electrolyte and electric vehicle battery material, and lithium carbonate as a battery material for general portable IT devices By recovering, the waste lithium-ion secondary battery can be recycled without leaving it, and by using carbon dioxide as a reactant in the electrolyte recovery process, valuable metal recovery process, and lithium synthesis process, carbon dioxide, a greenhouse gas, is largely reduced, and valuable metal and It was confirmed through experiments that lithium carbonate can be obtained in high yield, and the present invention was completed.

1 and 2 are schematic flowcharts of a recycling method of a waste lithium ion secondary battery according to an embodiment of the present invention.

First, a positive electrode material, a negative electrode material, a separator, and an electrolyte are separated and recovered from a waste lithium ion secondary battery or scrap, and then the positive electrode material and the negative electrode material are mechanically pretreated to obtain a pulverized product (step a).

As a raw material used in the above step, the waste lithium-ion secondary battery may be completely discharged, for example, water provided with salt or iron powder in a general stainless steel tank, and then immersed in the battery for a certain period of time to stir. -It can be completely discharged by making a short circuit and consuming all the remaining power inside the secondary battery. Meanwhile, the scrap is generated during the process of manufacturing a lithium ion secondary battery, and like the waste lithium ion secondary battery, may include one or more valuable metals selected from lithium, manganese, cobalt, and nickel.

On the other hand, the mechanical pre-treatment performed in the above step, unlike the thermal treatment process (Thermal treatment), sodium hydroxide solvent process (NaOH dissolution), solvent solvent process (Solvent dissolution) according to the prior art, has the advantage of no risk of fire or explosion There is an advantage that the pulverized product obtained through the mechanical pre-treatment process can be effectively selected through particle size, volume, and magnetic force. In addition, unlike the heat treatment process according to the prior art, there is no risk of generating toxic gas and there is no use of electricity or oil, so the initial investment cost is low. In addition, there is no separation membrane and electrolyte firing by heat treatment, so that the electrolyte can be recovered separately, thereby maximizing commercial benefits.

Through the mechanical pre-treatment step according to an embodiment of the present invention, the waste lithium ion secondary battery or scrap is a current collector crushed product made of aluminum and copper, and at least one selected from carbon, lithium, iron, manganese, cobalt, and nickel. An active material pulverized material containing LiPF ₆ , LiClO ₄ and one or more selected from LiBF ₄ , electrolyte and dimethyl sulfoxide (Dimethyl Sulfoxide), propylene carbonate (Propylene Carbonate), diethyl carbonate (Diethyl Carbonate), It is easily separated by a separator comprising an electrolyte solvent containing one or a combination selected from the group consisting of ethylene carbonate and dimethyl carbonate. In addition, materials such as iron and plastic that may be included according to the type of the secondary battery active material can be selectively separated according to the above method.

Specifically, the step, after completely discharging the waste lithium-ion secondary battery or the scrap, completely cooled with liquid nitrogen to solidify the electrolyte and the separator, selectively separate the positive electrode material and the negative electrode material from the separator and the electrolyte, and It can be carried out by putting it in a mechanical pre-treatment device.

Next, the separation membrane recovered in step a is subjected to supercritical carbon dioxide extraction (step b).

The step is for completely separating and recovering the electrolyte solution remaining in a trace amount in the separation membrane separated through the mechanical pretreatment process from the active material, and through the supercritical carbon dioxide extraction in the step, a trace amount of the electrolyte solution remaining in the interior and surface of the separation membrane Can be completely separated and recovered, thereby maximizing commercial profit.

Specifically, the supercritical carbon dioxide extraction treatment process performed in the above step may be performed in a supercritical facility under 20 to 40 Mpa pressure and 35 to 55°C temperature conditions, 50 to 80 minutes, and in detail, 4 per minute It can be carried out to be collected in a filter canister at a rate of liters. Meanwhile, the electrolyte that is separated and recovered through the above steps according to an embodiment of the present invention may be an electrolyte including one or more selected from LiPF ₆ , LiClO ₄ and LiBF ₄ . On the other hand, the electrolyte extraction yield (extraction yield) of the step may be 85 to 95%.

Next, the pulverized product obtained in step a is subjected to powder motion using an air jet sieve to separate graphite (step c).

In the above step, the pulverized material obtained in step a is powdered using an air jet sieve to separate graphite, which is a negative electrode active material contained in a waste lithium ion secondary battery or scrap. . Specifically, when the air jet powder is used, the graphite component, which is a relatively light carbon material, is easily separated by mass differences, and by repeating the above steps as necessary, the purity and recovery amount of the recovered graphite can be maximized. have. Specifically, the step may be performed 3 to 5 times.

Meanwhile, between steps c and d, the method may further include recovering at least one battery material selected from the group consisting of aluminum, copper, and iron. The above step is a process for separating and recovering residual aluminum, copper, and iron mixed in a trace amount in the pulverized active material, and may be for eliciting a chemical reaction between the pulverized product and the acid solution more easily in an acid leaching process described later.

Specifically, the aluminum recovery process may be performed for 2 to 6 hours, more specifically 4 hours, under room temperature conditions and a solid-liquid ratio of 10:1 using a 1-10% sodium hydroxide (NaOH) solution. As a result of the above step, 99.9% of aluminum remaining in the active material pulverized material is dissolved, and by filtering it, aluminum can be recovered separately.

The filtrate obtained through the above step can be collected as aluminum hydroxide using sodium hydroxide, and the unfiltered pulverized material can be extracted and recovered with higher purity through an acid leaching process described later.

On the other hand, specifically, the copper recovery process using 10 wt% sodium hydroxide (NaOH) solution, after crystallization of copper (II) hydroxide under 70 °C and 5.5 pH conditions, the carbon dioxide 2 parts by weight of copper hydroxide to 1 weight of carbon dioxide It may be recovered with basic copper carbonate to basic copper carbonate by adding it at a negative ratio. On the other hand, by consuming carbon dioxide as much as half of the copper recovery rate in this step, it is possible to implement an environmentally friendly process. The recovery rate of copper remaining in the active material pulverized by the above step reaches 98.5 to 99.5%.

On the other hand, specifically, the iron recovery process using sodium hydroxide (NaOH) solution of 10% by weight, under 90 to 100 ℃ and 3 to 3.5 pH conditions, sodium jarosite (Sodium jarosite) to iron hydroxide (Iron(II) hydroxide ), and by the above step, 99.9% of iron remaining in the active material pulverized material can be recovered.

Next, acid is leached by adding an acid solution to the pulverized product obtained in step c (step d).

The pulverized material may include a pulverized positive electrode material, a pulverized negative electrode material, or a pulverized material in which a positive electrode material and a negative electrode material are mixed, and the step is to selectively extract valuable metals contained in the pulverized material through a chemical reaction. It can be done.

Specifically, the step may be performed for 6 hours at a temperature condition of 3M sulfuric acid (H ₂ SO ₄ ), high liquid ratio (S/L) 1: 5, hydrogen peroxide (H ₂ O ₂ ) and 70° C., but is not particularly limited. It does not work. On the other hand, the temperature, acidity (pH level), reaction time, etc., which are required depending on the type of acid when acid leaching, can be adjusted as needed, and hydrochloric acid or phosphoric acid may be used in addition to the sulfuric acid.

Next, one or more valuable metals selected from the group consisting of manganese, cobalt, and nickel are extracted and recovered from the leach obtained in step d (step e).

Specifically, in the above step, the extraction of valuable metals may be in the order of manganese, cobalt, and nickel, and in the case of extraction in the order described above, the use of sodium hydroxide or acid necessary for pH control may be reduced, and also the recovery process of nickel It has the effect of minimizing the case where the cobalt is recovered together.

First, for the recovery of manganese, ammonium persulfate (Ammonium Persulfate) and 10% by weight of sodium hydroxide (NaOH) for pH adjustment are added to the acid leach obtained in step d. Specifically, in the above process, while maintaining the temperature in the range of 60 to 80°C, the pH is adjusted to 4, ammonium persulfate is first added, and sodium hydroxide is slowly added while maintaining the pH in the range of 3 to 5 to perform the reaction. And, if the leachate obtained through the above step is filtered, high purity manganese dioxide (MnO ₂ ) is first separated. On the other hand, manganese can be recovered at about 98.5% or more in the above step, and the purity is 99.5% or more, which can be directly used in the battery production process.

Next, for the recovery of cobalt, 2 to 3M of ammonium hydroxide ((NH ₄ )OH) is added to the leachate, and reacted while maintaining a pH range of 0.5 to 2 at a temperature of 65 to 75°C. Ammonium hydroxide and cobalt are in the range of 1.2:1 to 2:1. Meanwhile, the reaction may be performed for 4 to 5 hours, and cobalt hydroxide (Co(OH) ₂ ) may be extracted with a purity of 99.5 to 99.8% and a recovery rate of 99.0% or more. On the other hand, after the above step, with respect to cobalt, carbon dioxide is added at a weight ratio of 1: 1 to recover as cobalt carbonate (CoCO ₃ ). Meanwhile, an eco-friendly process can be implemented by consuming carbon dioxide at a cobalt recovery rate in this step.

Meanwhile, according to an embodiment of the present invention, an additional step for further increasing the recovery rate of the cobalt may be performed, and 1M Cyanex272 having a saponification rate of 10% is added, and a pH condition of 5.5 and a reaction time of 1 minute provide additional reaction. You can do After the reaction, when washed with 2M sulfuric acid with an organic/aqueous ratio of 1:1 for 1 minute at room temperature, cobalt sulfate is extracted, and the total recovery of cobalt recovered through the two-step reaction is about 99.0 to It corresponds to 99.8%.

Next, for nickel recovery, by adding 10% by weight of sodium hydroxide (NaOH) to the acid leachate, by adjusting the acidity (pH) in the range of 8 to 9, by reacting at room temperature for 1 to 3 hours, nickel hydroxide Crystallize with (Nickel(ll) hydroxide). Through this step, high purity nickel is recovered from the acid leachate. Meanwhile, in the above step, nickel may be recovered at a recovery rate of 99.1 to 99.8%. Meanwhile, the nickel recovered in the above step has a purity of 99.2% or more, and can be directly used in the battery production process.

Next, after step e, lithium hydroxide is extracted by adding a hydroxide to the obtained lithium acid solution (step f).

Lithium hydroxide is generally used as a battery material for electric vehicles, and at this stage, the lithium hydroxide extraction process can be performed by selecting and adding one of the hydroxides to the lithium acid solution. The lithium hydroxide extraction process according to an embodiment of the present invention is performed by adding calcium hydroxide (Ca(OH) ₂ ) to the lithium acid solution, and specifically, while adjusting the acidity (pH) in the range of 11 to 13, 90 to 120 It can be carried out by reacting for 3 to 5 hours under the temperature condition of ℃. The above step is performed based on the solubility of calcium sulfate and lithium hydroxide by temperature, and crystallization can be induced by minimizing the solubility of calcium sulfate at high temperature. In the reaction, calcium sulfate is a precipitate, and lithium hydroxide may be separated through a solid-liquid (solid/liquid) separation process. On the other hand, the lithium hydroxide obtained in the above step is in a liquid state, and is heated to a temperature range of 150 to 200°C for application in the production of an electric vehicle battery, and then vacuum dried to recover as solid lithium hydroxide.

Next, hydrogen peroxide is added to the lithium hydroxide obtained in step f to prepare a lithium peroxide solution (step g), and then carbon dioxide is added to the obtained lithium peroxide solution to prepare a lithium carbonate solution (step h).

Specifically, when hydrogen peroxide is added to the lithium hydroxide in the solid state extracted in the step f, lithium hydroperoxide (LiOOH) is formed. In this case, when dehydrogenation is further induced, lithium peroxide (LiO ₂ ) A solution is obtained. Specifically, by adding ethanol and 15% by weight of hydrogen peroxide in a weight ratio of 4:3 to 5:3 to lithium hydroxide in a solid state, by performing a chemical reaction for 1 to 3 hours under a temperature condition of 100 ℃, lithium hydro After forming the peroxide, it is further heated by vacuum to further induce a dehydrogenation reaction.

Next, the lithium peroxide solution obtained as described above reacts with carbon dioxide in the atmosphere in a weight ratio of 1 to 1 to adsorb carbon dioxide immediately, thereby causing a substitution reaction to produce a lithium carbonate solution. On the other hand, since the purity of the lithium carbonate solution produced through the above process corresponds to a high purity lithium carbonate in the range of 99.5 to 99.8%, it is directly applicable to the manufacture of batteries for portable IT devices such as mobile phones and notebooks.

On the other hand, in the above step, unlike the prior art, carbon dioxide in the gas phase is directly used for the production of lithium carbonate. That is, since the effect of reducing the carbon dioxide recovery rate by the lithium carbonate occurs, it is possible to reduce a large amount of carbon dioxide, which is the main cause of the greenhouse effect, and establish an environmentally friendly process when recycling the waste lithium ion secondary battery and/or scrap as a whole. It becomes possible.

Specifically, the process may be performed by reacting at room temperature for 4 hours to 6 hours.

According to the recycling method of a waste lithium-ion secondary battery according to an embodiment of the present invention as described above, scrap generated during the manufacturing process of a waste lithium-ion secondary battery or a lithium-ion secondary battery as a raw material, nickel through a series of processes, Anode materials including manganese and cobalt-containing valuable metals, anode materials including graphite, battery materials including aluminum, copper and iron, electrolytes, lithium hydroxide as an electric vehicle battery material, and lithium carbonate as a battery material for general portable IT devices By recovering, it is possible to recycle the waste lithium-ion secondary battery and scrap.

In addition, in the recycling process, carbon dioxide is used in an electrolyte recovery process, a valuable metal recovery process, and a lithium synthesis process, thereby reducing carbon dioxide in a large amount and obtaining an eco-friendly effect. In particular, when carbon dioxide recovered from an industry that emits carbon dioxide, such as thermal power generation, is applied to the above process in the recycling process, there is an advantage of maximizing the carbon dioxide reduction effect.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present description, descriptions of already known functions or configurations will be omitted to clarify the gist of the present description.

Example

Examples 1 to 2

Ten discharged lithium ion secondary batteries for smartphones (Example 1), and scraps generated during the production process of lithium ion secondary batteries (Example 2), each of which had been discharged, were prepared at 450g and 25g, respectively.

In Example 1, the upper part of the battery body was cut horizontally for direct dismantling (Manual Dismantling), immersed in liquid nitrogen (Deactivation), and rapidly cooled. Next, each of the batteries was disassembled and decomposed, respectively, to separate a negative electrode material, a positive electrode material, and a separation membrane (electrolyte solution and electrolyte are absorbed), and collected according to the types to confirm the weight first to obtain the results shown in Table 1 below.

Composition material weight ratio Example 1
(Total 450 g) unit Cathode material Cathode material Separator + Electrolyte Rest (battery shell, etc.) weight% 27.7 40.2 10.1 22.0 g 124.5 181.1 45.3 99.1

On the other hand, Example 2 is already categorized as a negative electrode material and a positive electrode material, respectively, and the above steps have not been performed (however, in the case of scrap, they are not completely separated).

After the above process, only the separation membrane was collected separately, and a supercritical carbon dioxide extraction process was performed. The inside of the container is set to an argon (Ar) atmosphere, and the moisture and oxygen saturation rate is maintained at less than 1 ppm, the purity of carbon dioxide used is 99.95%, the pressure is about 40 MPa, and the temperature is about 50 in the range of 50 to 60°C. Proceeded for a minute. To aid extraction, acetonitrile, propylene carbonate and LiPCl ₆ (lithium hexachlorophosphate) were added into the container at a ratio of 3: 1: 0.5 mL per minute. The extract was continuously collected in another tank at a rate of 4 liters per minute (Constant rate of 4.0 L/min). For the result analysis, first, by using the fact that the remaining electrolytic material is soluble in water, the supercritical carbon dioxide extraction process was completed by soaking it in water, and the weight was measured to obtain the results as shown in Table 2 below.

Separation membrane before supercritical extraction (g) Separation membrane after supercritical extraction (g) weight 45.3 g 21.6 g

Next, in order to know the recovery rate of the recovered LiPF ₆ (lithium hexafluoride) electrolyte, it was dissolved in hydrochloric acid having a pH concentration of less than 1 and analyzed by ICP-OES method. As a result, the recovery rate was confirmed to be more than 90%, and the purity also increased. Did.

Next, the negative electrode material and the positive electrode material of Example 1 were collected and pulverized through a mechanical pretreatment process, and the negative electrode material and positive electrode material of Example 2 were collected and pulverized through a mechanical pretreatment process. First, the obtained pulverized material was collected through an air jet powder, and the graphite was collected by a screening method using a difference in mass, and after repeating this step three times, the weight was measured to obtain the results shown in Table 3 below.

Content of recovered graphite (g) Example 1 48.9 Example 2 2.3

Next, the remaining negative electrode material and the positive electrode material pulverized material were first immersed in a 5% sodium hydroxide (NaOH) solution to dissolve aluminum. Specifically, it was performed for 4 hours under room temperature conditions and a high liquid ratio of 10:1. As a result of the above step, 99.9% of aluminum was dissolved and filtered, so that the filtrate could be additionally collected as aluminum hydroxide through pH control using sodium hydroxide, and the remaining unfiltered pulverized material was further purified by aluminum. .

Next, the pulverized material was dissolved in 3M sulfuric acid, a solid-liquid ratio (S/L) of 1:10, hydrogen peroxide (H ₂ O ₂ ) of 10% by weight, and dissolved at a temperature of 70° C. for 6 hours, and then each metal in the crushed material To measure the content of was measured with an atomic absorption spectrophotometer, and also to confirm the content of aluminum, the filtrate of the above step was also measured to obtain the results shown in Table 4 below.

Metal content lithium nickel manganese cobalt aluminum Copper iron Example 1 (g) 20.1 25.2 31.3 59.9 33.5 75.4 11.1 Example 2 (g) 1.05 - - 4.17 2.52 4.50 -

In the case of Example 1, the weight percent of the constituent materials was confirmed, and the content of copper measured in the negative electrode material consisting of graphite and copper foil was 56.5 g, and the copper content in the negative electrode constituent weight 124.5 g Minus 49.1 g of graphite was included. After three airjet powder process, the graphite recovery rate was 48.9/49.1*100, which was confirmed to be 99.6%. In the case of Example 2, the result of analyzing the carbon content in the acid leaching solution after the graphite recovery process was found to be 0.007 g, and the recovery rate was 99.7%.

Next, in order to recover iron from the sulfuric acid leachate, a process was performed for 2 hours at a temperature of 95° C. and 3.5 pH using a 10% by weight sodium hydroxide (NaOH) solution. As a result, sodium jarosite (Sodium jarosite) and iron hydroxide (Iron(II) hydroxide). To confirm the recovery of iron, the remaining sulfuric acid leachate was analyzed again, and the amount of iron remaining was found to be less than 0.001 g. In other words, the recovery rate of iron in the above step was confirmed to be 99.9%. On the other hand, in the case of Example 2, since iron was not included, the above step was omitted.

Next, Example 1 leachate and Example 2 leachate were used for 10% by weight of sodium hydroxide (NaOH) solution, and crystallized copper(II) hydroxide for 2 hours at 70°C and 5.5 pH. After extracting the copper hydroxide, the remaining amount of copper in the analysis of the remaining Example 1 leach solution was confirmed to be about 1.05 g, and the recovery was found to be 98.6%. Example 2 In the analysis of the leach solution, the residual amount of copper was found to be 0.0673 g, and thus, the recovery rate was confirmed to be 98.5%.

The copper hydroxide produced in this way adsorbs carbon dioxide in the air at room temperature, and can be recovered as basic copper carbonate or copper(II) carbonate. In the experimental stage, carbon dioxide is accelerated. Base copper carbon acid was combined by placing copper hydroxide at an incinerator outlet for discharging. The amount of carbon dioxide adsorbed in this process could be theoretically calculated through the formula 2Cu(OH) ₂ + CO ₂ → Cu ₂ CO ₃ (OH) ₂ + H ₂ O, and the carbon dioxide reduced in Example 1 was about 25.7 g. It was confirmed and the carbon dioxide reduced in Example 2 was found to be about 1.54 g. Although this amount may seem insignificant, when 3,000 tons of waste lithium ion secondary batteries are recycled annually, 172 tons and 184 tons of atmospheric carbon dioxide or carbon dioxide in the atmosphere are reduced, respectively.

To further recover the copper that achieved 98.5 to 98.6% recovery, or to increase the purity of cobalt and nickel in the next step, a chemical called Acorga M5640 was used for the remaining leach, and this step increased pH through recovery of the metals. To lower it again, 3M sulfuric acid was used, the pH was adjusted to 1 again, and it was carried out at room temperature. Crystallized by proceeding with a reaction time of about 10 minutes and filtered copper sulfate to 2M sulfuric acid in an Organic/Aqueous ratio of 1: 1 It was washed with a reaction time of 1 minute. The sulfuric acid washing step was repeated twice. Through this, the recovery rate was increased from 98.6% and 98.5% to 99.8% in both Example 1 and Example 2 through additional copper recovery.

Next, while adding 10 wt% sodium hydroxide (NaOH) to the sulfuric acid leachate of Example 1, adjusting the pH to 4.5, adjusting the temperature to 80°C, and adding ammonium persulfate, manganese dioxide (MnO ₂ ) crystallizes And this was filtered off. The recovery rate of manganese was also confirmed by analyzing the remaining filtered leach solution, and as a result, the remaining manganese was found to be 0.45 g and the recovery rate was 98.6%.

Next, the recovery of cobalt was carried out, 3M of ammonium hydroxide (NH ₄ )OH was added in a state adjusted to pH 1, and the reaction was performed at a temperature of 70° C., and the specific molar ratio was (ammonium hydroxide: cobalt) 1.5: 1 Proceeded from Meanwhile, the reaction was performed for 4 hours, and the recovery rate was 99% or more, and cobalt hydroxide (Co(OH) ₂ ) having a purity of 99.8% was extracted.

When carbon dioxide is added to the recovered cobalt hydroxide, it can be recovered as cobalt carbonate (CoCO ₃ ). In the experiment, the discharge time was accelerated by connecting the outlet through which the carbon dioxide was introduced into the ammonia water into a tube and putting the recovered cobalt hydroxide into reaction.

The amount of carbon dioxide adsorbed in this process could be theoretically calculated through the formula Co(OH) ₂ + CO ₂ → CoCO ₃ + H ₂ O, and the carbon dioxide reduced in Example 1 was confirmed to be about 44.28 g, and Example 2 The carbon dioxide reduced in was found to be about 3.08 g. Although this amount may seem insignificant, when 3,000 tons of waste lithium ion secondary batteries are recycled annually, 295 tons and 370 tons of atmospheric carbon dioxide or carbon dioxide in the atmosphere are generated, respectively.

Next, an experiment for nickel recovery was conducted, and 10% by weight of sodium hydroxide (NaOH) was added to the residual acid leaching liquid, and the pH was adjusted to 8.5 while reacting at room temperature for 2 hours. As a result, nickel hydroxide (Nickel(ll) hydroxide) was crystallized and filtered, and the remaining leach solution was analyzed again to confirm the recovery rate of 99.3% in Example 1, and Example 2 was deferred because there was no nickel content from the beginning. This step did not proceed.

Next, for the recovery of the last remaining 4 rare metals, lithium, a hydroxide was added to the remaining leach solution, the acidity (pH) was adjusted to 11, and the reaction was performed for 4 hours under a temperature condition of 100°C. The above step is performed based on the solubility by the temperature of calcium sulfate and lithium hydroxide, and crystallization was induced by minimizing the solubility of calcium sulfate at high temperature. As a result, the crystallized precipitate is calcium sulfate, and lithium hydroxide was separately separated into a liquid state through a solid-liquid (solid/liquid) separation process, and then put lithium hydroxide in a liquid state into a heating furnace and heated to a temperature range of 150° C., It was dried in vacuo and recovered with lithium hydroxide in a solid state.

Lithium hydroxide in this state can also induce conversion to lithium carbonate by adsorbing carbon dioxide, but in order to maximize carbon dioxide adsorption, conversion to lithium peroxide was carried out in this experiment. Ethanol and 15% by weight of hydrogen peroxide were prepared at a ratio of 4.5: 3, lithium hydroxide as a solid was added, mixed for 45 minutes under a temperature condition of 70° C. or less, and heated to 100° C. for 20 minutes. As a result, lithium hydroperoxide (LiOOH) was formed. Here, vacuum heating was continued for dehydration, and reaction was performed at a temperature of 120° C. for about 2 hours to obtain a lithium peroxide (Li ₂ O ₂ ) solution. lost. In the experiment, the recovery rate of lithium peroxide was confirmed to be 94% for Example 1 and 95% for Example 2.

The thus obtained lithium peroxide can be converted into lithium carbonate by directly adsorbing carbon dioxide in the atmosphere. For this, specifically, the experiment was conducted at room temperature for about 5 hours. The amount of carbon dioxide adsorbed in this process could be theoretically calculated through the formula 2Li ₂ O ₂ + 2CO ₂ → 2Li ₂ CO ₃ + O ₂ , and the reduced carbon dioxide in Example 1 was confirmed to be about 59.38 g, and in Example 2 The reduced carbon dioxide was found to be about 3.14 g. Although this amount may seem insignificant, when 3,000 tons of waste lithium ion secondary batteries are recycled per year, 396 tons or 376 tons of atmospheric carbon dioxide or carbon dioxide in the atmosphere are generated, respectively.

According to the recycling method of a waste lithium-ion secondary battery having a series of the above-described sequence, a scrap material generated during the manufacturing process of a waste lithium-ion secondary battery or a lithium-ion secondary battery is used as a raw material, and a cathode material including valuable metals through a series of processes, By recovering the negative electrode material including graphite, electrolyte and lithium hydroxide, which is an electric vehicle battery material, and lithium carbonate, which is a battery material of a typical portable IT device, waste lithium ion secondary batteries and scraps can be recycled without leaving.

In addition, according to the recycling method of a waste lithium ion secondary battery according to an embodiment of the present invention, carbon dioxide is used in an electrolytic recovery process, a valuable metal recovery process, and a lithium synthesis process, thereby reducing carbon dioxide in a large amount and having an eco-friendly effect. It is environmentally friendly because it can be obtained.

In the foregoing, although specific embodiments of the present invention have been described and illustrated, the present invention is not limited to the described embodiments, and it is common knowledge in the art that various modifications and modifications can be made without departing from the spirit and scope of the present invention. It is obvious to those who have it. Therefore, such modifications or variations should not be individually understood from the technical spirit or viewpoint of the present invention, and the modified embodiments should belong to the claims of the present invention.

Claims (4)

a) separating and recovering the positive electrode material, the negative electrode material, the separator, and the electrolyte from the waste lithium ion secondary battery or scrap, and then mechanically pretreating the positive electrode material and the negative electrode material to obtain a pulverized material;
b) subjecting the separation membrane recovered in step a to supercritical carbon dioxide extraction within a temperature range of 30 to 55°C and a pressure condition of 20 to 40 MPa;
c) separating the graphite by pulverizing the pulverized product obtained in step a using an Air Jet Sieve;
d) acid leaching by adding an acid solution to the pulverized product obtained in step c;
e) extracting and recovering at least one valuable metal selected from the group consisting of manganese, cobalt and nickel from the leach obtained in step d;
f) after step e, extracting lithium hydroxide by adding a hydroxide to the obtained lithium acid solution;
g) after step f, adding hydrogen peroxide to the obtained lithium hydroxide to prepare a lithium peroxide solution; And
h) after step g, adding carbon dioxide to the obtained lithium peroxide solution to prepare a lithium carbonate solution; It includes,
A method of recycling a waste lithium ion secondary battery, which uses carbon dioxide in the atmosphere to reduce carbon dioxide in a large amount in the separation membrane and electrolyte recovery process in step b, a valuable metal recovery process in step e, and a lithium carbonate solution production step in step h. delete According to claim 1,
Between the steps c and d, further comprising the step of recovering at least one battery material selected from the group consisting of aluminum, copper, and iron, recycling method of a waste lithium ion secondary battery. According to claim 1,
The waste lithium ion secondary battery or scrap is a current collector pulverized material composed of aluminum and copper, and an active material pulverized material including at least one selected from carbon, lithium, iron, manganese, cobalt, and nickel, and LiPF ₆ , LiClO ₄ and Electrolyte containing at least one selected from LiBF ₄ and dimethyl sulfoxide, propylene carbonate, diethyl carbonate, ethylene carbonate, and dimethyl carbonate ) Comprising a separator comprising an electrolyte solvent containing one or a combination selected from the group consisting of, a method of recycling a waste lithium ion secondary battery.

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