Recovery system for dry recycling of waste secondary battery capable of reducing carbon dioxide and recovery method using same

Abstract

The purpose of the present invention is to provide: a recovery system for dry recycling of a waste secondary battery, wherein the recovery system can use low-grade waste secondary battery powder, produce large amounts of lithium carbonate, and reduce carbon dioxide; and a recovery method using same. In order to achieve the purpose, the present invention is characterized by comprising: a supply unit including a hopper for supplying a cell powder, a first valve for transferring the supplied cell powder, and a second valve for providing carbon dioxide to the transferred cell powder; a process chamber including a heating device for heating the cell powder in the provided carbon dioxide atmosphere, a first cooling unit for cooling the heated cell powder, and a second cooling unit for cooling the cell powder transferred from the first cooling unit; and a discharge unit for discharging the cell powder transferred from the second cooling unit, wherein the system is a rotary kiln system.

Description

A recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide emissions and a recovery method using the same

[0001] The present invention relates to a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide and a recovery method using the same, and more specifically, to a recovery system for dry recycling of waste secondary batteries capable of using low-grade waste secondary battery powder, mass production of lithium carbonate, and reducing carbon dioxide, and a recovery method using the same.

[0002] A secondary battery is a lithium ion battery, consisting of a positive electrode, a negative electrode, an organic electrolyte, and an organic separator. Specifically, it consists of a plastic casing, a positive electrode, a negative electrode, an organic separator, an organic electrolyte contained within multiple cell units, and a nickel-coated steel casing.

[0003] Lithium (Li), which is used as a cathode material in secondary batteries, is unstable when used alone, so it exists as lithium metal oxide, which is a form combined with other metal elements.

[0004] A representative cathode material for secondary batteries is NCM (LiNiCoMnO2). NCM types have nickel, cobalt, and manganese in ratios of 6:2:2, 8:1:1, or 9:1 / 2:1 / 2, increasing the proportion of nickel. Because of its high energy density, it is most commonly used as a cathode material for electric vehicles.

[0005] Additionally, LCO (LiCoO2) is used as a cathode material for secondary batteries. LCO has the characteristics of high energy density and long lifespan, and is mainly used in small IT devices.

[0006] In the prior art, wet and dry methods have been reported for recovering lithium from NCM-based secondary batteries.

[0007] The waste secondary battery powder obtained by crushing / pulverizing can be divided according to the carbon content.

[0008] In this technical field, waste secondary battery powder can be divided into cell powder, black mass or black sand, and black powder according to carbon content, where cell powder is defined as low-grade with the highest carbon content.

[0009] The wet method involves leaching the positive active material in waste secondary batteries that have undergone heat treatments such as discharge, decomposition, heat treatment, and crushing with inorganic acid, alkali, or organic acid, and then recovering lithium together with nickel, cobalt, etc. by using solvent extraction, etc.

[0010] Meanwhile, the above-described wet method has the disadvantage of causing environmental problems and the cost of processing by-products generated during lithium recovery.

[0011] In the prior art, the wet method collected waste secondary batteries, crushed them, and used the obtained black mass, which was advantageous for lithium recovery.

[0012] The dry method is to obtain waste secondary battery powder by crushing / classifying it into a certain size, and then form lithium carbonate through a thermal decomposition process using carbon dioxide (CO2), and then recover lithium through water leaching.

[0013] The above-described dry method can process a large amount of waste secondary battery powder to recover a large amount of lithium carbonate, and has the advantage of being environmentally friendly because it uses carbon dioxide gas.

[0014] In the prior art, the dry method used black powder obtained by crushing / pulverizing defective waste materials discarded during the manufacturing process of positive electrode materials for secondary batteries, which was advantageous for lithium recovery.

[0015] Accordingly, the applicant, through painstaking efforts, has completed the present invention by obtaining a recovery system for dry recycling of waste secondary batteries and a recovery method using the same, which enables the use of low-grade waste secondary battery powder, mass production of lithium carbonate, and reduction of carbon dioxide.

[0016] The present invention, which aims to solve the above-mentioned conventional problems, aims to provide a recovery system for dry recycling of waste secondary batteries, which enables the use of low-grade waste secondary battery powder, enables mass production of lithium carbonate, and reduces carbon dioxide emissions.

[0017] The present invention, which aims to solve the above-mentioned conventional problems, aims to provide a recovery method for dry recycling of waste secondary batteries, which enables the use of low-grade waste secondary battery powder, enables mass production of lithium carbonate, and reduces carbon dioxide emissions.

[0018] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0019] In order to achieve the above task, according to one aspect of the present invention,

[0020] As a recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions,

[0021] A supply unit including a hopper for supplying cell powder, a first valve for transporting the supplied cell powder, and a second valve for supplying carbon dioxide to the transported cell powder;

[0022] A process chamber including a heating device for heating the cell powder in the provided carbon dioxide atmosphere, a first cooling unit for cooling the heated cell powder, and a second cooling unit for cooling the cell powder transferred from the first cooling unit; and

[0023] It includes a discharge unit that discharges the cell powder transferred from the second cooling unit;

[0024] The above system is characterized by being a rotary kiln system.

[0025] Additionally, the cell powder is characterized by containing nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C).

[0026] Additionally, the cell powder is characterized by having a carbon (C) content of 29.5% or less.

[0027] In addition, the cell powder is characterized in that it contains at least one selected from boron (B), calcium (Ca), chromium (Cr), iron (Fe), potassium (K), magnesium (Mg), sodium (Na), phosphorus (P), titanium (Ti), zinc (Zn), zirconium (Zr), silicon (Si), fluorine (F), and nitrate (NO3).

[0028] Additionally, the cell powder is characterized by having a lithium (Li) content of 3 to 7 wt%.

[0029] In addition, the carbon dioxide is characterized as being either an industrial gas or a gas generated from a power plant.

[0030] In addition, the temperature of the heating device is characterized by being 800°C to 1000°C.

[0031] In addition, the flow rate of the carbon dioxide inside the process chamber is characterized by being 10 to 12 L / min.

[0032] In addition, the rotary kiln is characterized in that it is operated under conditions of an angle of 10° or less and a rotation speed of 1 to 1.5 rpm.

[0033] In order to achieve the above task, according to another aspect of the present invention,

[0034] The recovery method is characterized by using a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide as described above.

[0035] And, the recovery method according to the present invention,

[0036] (a) A step of thermally decomposing cell powder in an oxygen-free atmosphere under carbon dioxide conditions to obtain a thermal decomposition product containing lithium carbonate (Li2CO3);

[0037] (b) a step of crushing / classifying the above pyrolysis product;

[0038] (c) a step of separating the solid and liquid phases by leaching the above crushed / classified pyrolysis product; and

[0039] (d) a step of obtaining lithium carbonate by distilling the solution obtained in a liquid phase containing the lithium carbonate under reduced pressure;

[0040] In addition, the carbon dioxide is characterized as being either an industrial gas or a gas generated from a power plant.

[0041] In addition, the cell powder is characterized by containing nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C).

[0042] In addition, the step (a) is characterized by including a step of thermal decomposition in a temperature range of 800°C to 1000°C.

[0043] In addition, the thermal decomposition product is characterized in that it contains at least one selected from nickel, manganese, cobalt and oxides thereof together with lithium carbonate.

[0044] In addition, the step (b) is characterized by including a step of crushing using a steel ball.

[0045] In addition, in the above step (c), the water leaching process is characterized by being a high-liquid ratio 1:20, single-stage water leaching process.

[0046] In addition, it is characterized in that the recovery rate of the lithium carbonate in the above step (d) is 90% or more.

[0047] In addition, the purity of the lithium carbonate obtained in the above step (d) is characterized by being 99.7% or higher.

[0048] According to the present invention, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide emissions and using low-grade waste secondary battery powder is provided.

[0049] According to the present invention, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide and mass production of lithium carbonate is provided.

[0050] According to the present invention, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide is provided, which easily obtains a pyrolysis product containing lithium carbonate by pyrolyzing cell powder in an oxygen-free atmosphere under carbon dioxide conditions, which is a reducing atmosphere, and selectively recovers lithium carbonate therefrom.

[0051] According to the present invention, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide emissions and using low-grade waste secondary battery powder is provided.

[0052] According to the present invention, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide and mass production of lithium carbonate is provided.

[0053] According to the present invention, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide is provided, in which cell powder is thermally decomposed in an oxygen-free atmosphere under carbon dioxide conditions as a reducing atmosphere as a dry process to easily obtain a thermal decomposition product containing lithium carbonate, and lithium carbonate is selectively recovered therefrom.

[0054] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0055] Figure 1 relates to a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0056] Figure 2 is a process diagram of a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0057] Figure 3 is an X-ray diffraction diagram of a pyrolysis product of a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0058] Figure 4 is a graph of the leaching rate according to the high liquid ratio of the recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0059] FIG. 5 is a photograph of lithium carbonate obtained after reduced pressure distillation in a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0060] Figure 6 is a result of analysis of the purity of lithium carbonate obtained by a recovery system and recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0061] FIG. 7 is a photograph of a prototype of lithium carbonate obtained in large quantities using a recovery system and recovery method for dry recycling of a lithium-ion battery capable of reducing carbon dioxide according to one embodiment of the present invention.

[0062] FIG. 8 is an X-ray diffraction diagram of a pyrolysis product obtained using carbon dioxide generated from a power plant in a recovery method according to one embodiment of the present invention.

[0063] The present invention, which aims to solve the above-mentioned conventional problems, aims to provide a recovery system for dry recycling of waste secondary batteries, which enables the use of low-grade waste secondary battery powder, enables mass production of lithium carbonate, and reduces carbon dioxide emissions.

[0064] The present invention, which aims to solve the above-mentioned conventional problems, aims to provide a recovery method for dry recycling of waste secondary batteries, which enables the use of low-grade waste secondary battery powder, enables mass production of lithium carbonate, and reduces carbon dioxide emissions.

[0065] Before describing the present invention in detail, it should be understood that the terms or words used in this specification should not be interpreted as being unconditionally limited to their usual or dictionary meanings, and that the inventor of the present invention may appropriately define and use the concepts of various terms in order to explain his or her invention in the best possible manner, and further, that these terms or words should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention.

[0066] That is, it should be noted that the terms used in this specification are only used to describe preferred embodiments of the present invention, and are not intended to specifically limit the contents of the present invention, and that these terms are defined in consideration of various possibilities of the present invention.

[0067] Additionally, it should be noted that in this specification, singular expressions may include plural expressions unless the context clearly indicates a different meaning, and similarly, even if expressed in plural, may include a singular meaning.

[0068] Throughout this specification, whenever a component is described as "including" another component, it may mean that the component may further include any other component, rather than excluding any other component, unless specifically stated otherwise.

[0069] In addition, in the following description of the present invention, a detailed description of a configuration that is judged to unnecessarily obscure the gist of the present invention, for example, a known technology including a prior art, may be omitted.

[0070]

[0071] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

[0072]

[0073] Figure 1 relates to a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0074]

[0075] According to FIG. 1, a recovery system (100) for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention may include a supply unit (102), a hopper (104), a first valve (106), a second valve (108), a process chamber (110), a heating device (112), a first cooling unit (114), a second cooling unit (116), and a discharge unit (118).

[0076]

[0077] The recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide as described above is, in detail,

[0078] A supply unit including a hopper for supplying cell powder, a first valve for transporting the supplied cell powder, and a second valve for supplying carbon dioxide to the transported cell powder;

[0079] A process chamber including a heating device for heating the cell powder in the provided carbon dioxide atmosphere, a first cooling unit for cooling the heated cell powder, and a second cooling unit for cooling the cell powder transferred from the first cooling unit; and

[0080] It includes a discharge unit that discharges the cell powder transferred from the second cooling unit;

[0081] The above system is characterized by being a rotary kiln system.

[0082]

[0083] More specifically, the hopper (104) is a V-shaped mechanism for transporting cell powder to the first valve.

[0084] The above first valve (106) is for transferring the cell powder transferred from the hopper to the second valve. The first valve is an on-off valve, and when the first valve is opened, the cell powder is transferred to the second valve, and after being transferred, the first valve is closed.

[0085] The second valve (108) supplies carbon dioxide to the cell powder transferred from the first valve. The second valve is an on-off valve. The cell powder is transferred to the process chamber (110) together with the carbon dioxide provided when the second valve, which is connected to an industrial carbon dioxide gas tank, is opened. After the cell powder and carbon dioxide are transferred to the process chamber, the second valve is closed.

[0086] Here, only carbon dioxide is supplied to the process chamber without using a vacuum pump to create a vacuum atmosphere or purging any gas into the vacuum atmosphere prior to supplying carbon dioxide.

[0087] The above process chamber (110) is in the form of a rotary kiln.

[0088] A rotary kiln is a heat treatment furnace that heats the cell powder and carbon dioxide by rotating the cylinder to cause a thermal decomposition reaction.

[0089] The above heating device (112) is a device that applies heat to the cell powder and carbon dioxide gas transferred from the second valve so that a thermal decomposition reaction occurs. The thermal decomposition reaction occurs in an oxygen-free atmosphere under carbon dioxide conditions, i.e., in a reducing atmosphere in which oxygen is substantially absent.

[0090] The first cooling unit (114) above cools the cell powder that has undergone a thermal decomposition reaction by a heating device. Here, the cell powder that has undergone a thermal decomposition reaction is cooled by air cooling, and the cooled cell powder is transferred to the second cooling unit.

[0091] The second cooling unit (116) re-cools the cell powder that has been cooled and transferred from the first cooling unit. Here, the cooled cell powder is transferred to the outlet.

[0092]

[0093] The cell powder may include, but is not particularly limited to, nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C). For example, it may be a powder obtained by crushing / pulverizing a waste secondary battery using LCO (LiCoO2) as a cathode material.

[0094] In the present invention, aluminum is a positive electrode current collector, copper is a negative electrode current collector, carbon is a negative electrode material, and a spent secondary battery using NCM (LiNiCoMnO2) as a positive electrode material can be crushed / pulverized to obtain cell powder.

[0095] The waste secondary battery powder obtained by crushing / pulverizing can be divided according to the carbon content.

[0096] In this technical field, waste secondary battery powder can be divided into cell powder, black mass or black sand, and black powder according to carbon content, where cell powder is defined as low-grade with the highest carbon content.

[0097] The above cell powder may have a carbon (C) content of 29.5 wt% or less.

[0098] Cell powder refers to a secondary battery manufactured using powder that is not pure raw material and is crushed / pulverized, and indicates that the carbon, which is an anode active material, is 30 wt% or less.

[0099] Black mass refers to a powder obtained by collecting and crushing waste secondary batteries, and indicates that carbon, which is an anode active material, is less than 5 wt%.

[0100] Black powder refers to the powder obtained by collecting and crushing waste secondary batteries that are generated due to defective positive electrode powder during the positive electrode material manufacturing process of secondary batteries, and indicates that it contains the lowest amount of carbon, which is an anode active material.

[0101] Lithium carbonate can be obtained through the above-described recovery system using the low-grade waste secondary battery powder described above.

[0102] Additionally, lithium carbonate can be obtained through the above-described recovery system using the above-described black mass or black powder.

[0103] The above cell powder may include at least one selected from boron (B), calcium (Ca), chromium (Cr), iron (Fe), potassium (K), magnesium (Mg), sodium (Na), phosphorus (P), titanium (Ti), zinc (Zn), zirconium (Zr), silicon (Si), fluorine (F), and nitrate (NO3).

[0104] The above cell powder may have a lithium (Li) content of 3 to 7 wt%.

[0105] The above carbon dioxide may be either an industrial gas or a gas generated from a power plant.

[0106] Here, carbon dioxide gas generated from power plants can have a purity of less than 5%. Even in a reducing atmosphere using low-grade carbon dioxide generated at such sites, high-purity lithium carbonate can be produced. This contributes to carbon neutrality and ensures economic viability.

[0107] The temperature of the above heating device can be 800°C to 1000°C.

[0108] Here, when the temperature of the heating device is within the above range, thermodynamically stable lithium carbonate (Li2CO3) can be formed, and no other lithium compounds other than lithium carbonate are formed, so that the recovery rate and purity of lithium carbonate can be improved.

[0109] The flow rate of the carbon dioxide inside the process chamber may be 10 to 12 L / min.

[0110] Here, when the flow rate of the carbon dioxide is within the above range, the thermal decomposition reaction of the entire injected cell powder and carbon dioxide can proceed completely, and the recovery rate of lithium carbonate can be improved.

[0111] Additionally, the rotary kiln may be operated under conditions of an angle of 10° or less and a rotation speed of 1 to 1.5 rpm.

[0112] Here, when the angle and rotation speed of the rotary kiln are within the above range, the contact area between the provided carbon dioxide and the cell powder increases, so that the recovery rate of lithium carbonate can be improved.

[0113] If the angle of the rotary kiln exceeds 10°, the cell powder is transported quickly within the rotary kiln, so it can be discharged before the thermal decomposition reaction occurs.

[0114] If the rotation speed of the rotary kiln is less than 1 rpm, the contact area between the provided carbon dioxide and the cell powder may decrease, causing an incomplete thermal decomposition reaction. If it exceeds 1.5 rpm, the transport of the cell powder within the rotary kiln may be accelerated, causing it to be discharged before the thermal decomposition reaction occurs.

[0115] According to one embodiment of the present invention, the recovery method uses the recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide as described above.

[0116] And, the recovery method according to the present invention,

[0117] (a) A step of thermally decomposing cell powder in an oxygen-free atmosphere under carbon dioxide conditions to obtain a thermal decomposition product containing lithium carbonate (Li2CO3);

[0118] (b) a step of crushing / classifying the above pyrolysis product;

[0119] (c) a step of separating the solid and liquid phases by leaching the above crushed / classified pyrolysis product; and

[0120] (d) a step of obtaining lithium carbonate by distilling the solution obtained in a liquid phase containing the lithium carbonate under reduced pressure;

[0121] The above carbon dioxide may be either an industrial gas or a gas generated from a power plant.

[0122] Here, carbon dioxide gas generated from power plants can have a purity of less than 5%. Even in a reducing atmosphere using low-grade carbon dioxide generated at such sites, high-purity lithium carbonate can be produced. This contributes to carbon neutrality and ensures economic viability.

[0123] The above-mentioned cell powder may include nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C), but is not particularly limited thereto. For example, it may be a powder obtained by crushing / pulverizing a waste secondary battery using LCO (LiCoO2) as a cathode material.

[0124] In the present invention, aluminum is a positive electrode current collector, copper is a negative electrode current collector, carbon is a negative electrode material, and a spent secondary battery using NCM (LiNiCoMnO2) as a positive electrode material can be crushed / pulverized to obtain cell powder.

[0125] The waste secondary battery powder obtained by crushing / pulverizing can be divided according to the carbon content.

[0126] In the present technical field, waste secondary battery powder can be divided into cell powder, black mass, black sand, and black powder according to carbon content, where cell powder is defined as low-grade with the highest carbon content. The cell powder may have a carbon (C) content of 29.5 wt% or less.

[0127] Cell powder refers to a secondary battery manufactured using powder that is not pure raw material and is crushed / pulverized, and indicates that the carbon, which is an anode active material, is 30 wt% or less.

[0128] Black mass refers to a powder obtained by collecting and crushing waste secondary batteries, and indicates that carbon, which is an anode active material, is less than 5 wt%.

[0129] Black powder refers to the powder obtained by collecting and crushing waste secondary batteries that are generated due to defective positive electrode powder during the positive electrode material manufacturing process of secondary batteries, and indicates that it contains the lowest amount of carbon, which is an anode active material.

[0130] Lithium carbonate can be obtained through the above recovery method using the low-grade waste secondary battery powder described above.

[0131] In addition, lithium carbonate can be obtained through the above-described recovery method using the black mass or black powder described above.

[0132] Step (a) is a step of thermally decomposing cell powder in an oxygen-free atmosphere under carbon dioxide conditions to obtain a thermal decomposition product containing lithium carbonate (Li2CO3).

[0133] Here, the anoxic atmosphere under carbon dioxide conditions refers to a reducing atmosphere in which practically no oxygen exists.

[0134] The above step (a) may include a step of thermal decomposition in a temperature range of 800°C to 1000°C.

[0135] Here, when the temperature of the heating device is within the above range, thermodynamically stable lithium carbonate (Li2CO3) can be formed, and no other lithium compounds other than lithium carbonate are formed, so that the recovery rate and purity of lithium carbonate can be improved.

[0136] The above pyrolysis product may include at least one selected from nickel, manganese, cobalt, and oxides thereof, together with lithium carbonate. Examples of components other than lithium carbonate included in the pyrolysis product may include nickel oxide (NiO), cobalt oxide (CoO), and the like.

[0137] Step (b) is a step of crushing / classifying the pyrolysis product.

[0138] The above pyrolysis product can be pulverized using a dry pulverizer, preferably a ball mill.

[0139] Here, when the pyrolysis product is pulverized using the ball mill, the particle size of the pulverized pyrolysis product can be adjusted to improve the specific surface area during water leaching, and the recovery rate and purity of lithium carbonate can be improved.

[0140] The above step (b) may include a step of crushing using a steel ball.

[0141] The above-mentioned crushed pyrolysis product can be classified by sieving.

[0142] Here, when the steel balls are filled to 50 vol.% of the ball mill pot, more than 98% of the pulverized pyrolysis products can pass through a #12 sieve (aperture size 1.68 mm), and the pyrolysis products obtained thereafter can improve the specific surface area during water leaching and improve the recovery rate and purity of lithium carbonate.

[0143] Step (c) is a step of separating solid and liquid substances by leaching the crushed / classified pyrolysis product.

[0144] The thermal decomposition products obtained after the above thermal decomposition step may include lithium carbonate, nickel oxide (NiO), and cobalt oxide (CoO). Here, since the above substances have different solubilities in water, lithium carbonate can be recovered by water leaching by utilizing this property.

[0145] In the above step (c), the water leaching process may be a high-liquid ratio 1:10, two-stage water leaching process or a high-liquid ratio 1:20, one-stage water leaching process, and preferably, it may be a high-liquid ratio 1:20, one-stage water leaching process.

[0146] Here, when the above-mentioned water leaching process is under the above conditions, the lithium leaching rate can be 98% or more, and in particular, a large amount of lithium carbonate with improved recovery rate and purity can be obtained in a single-stage water leaching process with a high-liquid ratio of 1:20.

[0147] Step (d) is a step of obtaining lithium carbonate by distilling a solution obtained in a liquid phase containing lithium carbonate under reduced pressure.

[0148] Here, when the solution obtained as a liquid containing the lithium carbonate is subjected to the reduced pressure distillation, the specific surface area of ​​the solution obtained as a liquid containing the lithium carbonate, i.e., the leachate, can be maximized, energy costs can be reduced, and the recovery rate and purity of the crystallized lithium carbonate can be improved.

[0149] In the above step (d), the recovery rate of the lithium carbonate may be 90% or more.

[0150] The purity of the lithium carbonate obtained in the above step (d) may be 99.7% or more.

[0151] As described above, the recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention has the advantageous effect of enabling the use of low-grade waste secondary battery powder and mass production of lithium carbonate.

[0152] In addition, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention has the effect of improving the recovery rate and purity of lithium carbonate even when using low-grade waste secondary battery powder.

[0153] In addition, the recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention is environmentally friendly because it does not use any hazardous substances, and has the effect of fundamentally reducing the cost of waste solution treatment.

[0154] In addition, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention provides a simple and easy process for recovering lithium carbonate through a pyrolysis process in an oxygen-free atmosphere using only carbon dioxide.

[0155] Hereinafter, the effect of mass-producing lithium carbonate using low-grade waste secondary battery powder according to one embodiment of the present invention will be described.

[0156] Lithium carbonate was recovered through the following example.

[0157]

[0158] <Example> Recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide emissions

[0159] <Example 1-1> Analysis of cell powder components

[0160] NCM secondary batteries manufactured using industrial powders with impure raw materials were placed in a ball mill together with steel balls to prepare cell powder by crushing / pulverizing them. The components of the cell powder were analyzed using X-ray fluorescence (XRF), inductively coupled plasma optical spectroscopy (ICP-OES), and an elemental analyzer. The analysis results are shown in [Table 1] below.

[0161] Elemental content (ppm) Content (wt%)Ni-28.60Mn-3.40Co-3.10Li-4.40Al-1.50B558BaN.D.Ca813Cr28Cu-3.60Fe473-K215-Mg320-MoN.D.-Na1691-P1086-PbN.D.-Ti178-Zn321-Zr79-Si116-F1920-NO3110-C-29.50

[0162]

[0163] Referring to the above [Table 1], the cell powder contained nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C), and in particular, the carbon content was 29.50 wt%. Here, when the carbon content in the cell powder is reflected, the lithium content was diluted to approximately 3.4 wt%.

[0164]

[0165] <Example 1-2> Analysis of black mass components

[0166] NCM waste secondary batteries were collected and placed in a ball mill with steel balls to crush and pulverize black mass. The components of the black mass were analyzed using X-ray fluorescence (XRF) and inductively coupled plasma optical spectroscopy (ICP-OES), and carbon was analyzed using an elemental analyzer. The analysis results are shown in [Table 2] below.

[0167] Elemental NiCoMnLiCS content (wt%) 60.5 22.7 16.8 5.4 22.21~3.0 30.02~0.06

[0168]

[0169] Referring to the above [Table 2], it was confirmed that black mass contained nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), carbon (C), and sulfur (S), and in particular, the carbon content was less than 5 wt%.

[0170]

[0171] <Example 1-3> Temperature effect on thermal decomposition reaction

[0172] The raw material of the above Example 1-1 or 1-2 was subjected to a pyrolysis reaction in an oxygen-free atmosphere under carbon dioxide conditions at different heating temperatures, and the pyrolysis products were analyzed using an X-ray diffractometer (XRD).

[0173] Figure 3 is an X-ray diffraction diagram of a pyrolysis product of a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0174] As shown in Fig. 3, no Li compounds other than lithium carbonate (Li2CO3) were observed at temperatures above 800°C. Therefore, it is believed that a temperature of 800°C or higher is desirable for the thermal decomposition process.

[0175]

[0176] <Example 1-4> Effect of angle and rotation speed on thermal decomposition reaction

[0177] Using the raw material of Example 1-1 or 1-2, the cell powder obtained by passing through a #12 sieve was charged into a laboratory-scale rotary kiln, and then lithium carbonate was obtained through a pyrolysis process in an oxygen-free atmosphere under carbon dioxide conditions. The process conditions are as shown in [Table 3] below.

[0178] Reaction temperature (℃) Total reaction time (min) CO2 (g) flow rate (L / min) Injection amount (kg) Li recovery rate (%) Rotation speed (rpm) Angle (°) Note * Field conductivity meter 900600.30.585.575412 900600.30.597.635412 Steel ball injection (LD 40mm) 900600.20.592.675412 900600.30.595.655412

[0179]

[0180] Referring to the above [Table 3], 0.5 kg of cell powder was charged into a rotary kiln, and the pyrolysis process was performed under the conditions of a pyrolysis reaction temperature of 900°C, a carbon dioxide flow rate of 0.3 L / min., a rotation speed of 54 rpm, and a rotation angle of 12° in Examples 1-3. When cell powder milled using steel balls was pyrolyzed under the above conditions, the Li recovery rate from the pyrolysis product was 90% or more, and up to 97%. Therefore, the above conditions were selected as the optimal conditions for the pyrolysis process when using a laboratory-scale rotary kiln.

[0181] The present invention relates to a recovery system for dry recycling of waste secondary batteries capable of mass production of lithium carbonate and reduction of carbon dioxide, and a recovery method using the same.

[0182] That is, it was confirmed that the rotary kiln can mass-produce lithium carbonate under the conditions of an angle of 10°, a rotation speed of 1 rpm, and a carbon dioxide flow rate of 10 L / min when applied to a pilot facility by utilizing the process conditions obtained through the above laboratory-scale test.

[0183]

[0184] <Example 1-5> Effect of high liquid ratio in water leaching

[0185] The thermal decomposition products containing lithium carbonate obtained in Examples 1-3 were subjected to water leaching in laboratory-scale tests. The leaching rate of Li according to the solid-to-liquid ratio in the water leaching process was analyzed. The solid-to-liquid ratios were selected as 1:5, 1:8, 1:9, and 1:10, and a two-stage water leaching process was performed. The amount of Li leached from the water leaching solution was analyzed using an inductively coupled plasma optical spectroscopy (ICP-OES). The analysis results are shown in [Table 4] below.

[0186] Slurry density (1:5, solute : solvent) Slurry density (1:8, solute : solvent) * Li2CO3 concentration (mg / L) Residue (g) Solvent usage (L) Li2CO3 content (mg) Li content (g) Percentage (%) * Li2CO3 concentration (mg / L) Residue (g) Solvent usage (L) Li2CO3 content (mg) Li Content (g)Percentage (%)10,3660.55,1830.972910,2940.88,2371.553510,79698.510.495,31813010,44496.930.788,0991.523510,41487.780.414,2580.8249,77887.410.76,8381.28297,66973.240.372,8080.531630082.280.661970.04143262.50.311350.031062.50.5000Slurry density (1:9, solute : solvent)Slurry density (1:10, Solute: Solvent)*Li2CO3 Concentration (mg / L)Residue (g)Solvent Amount (L)Li2CO3 Content (mg)Li Content (g)Percentage (%)*Li2CO3 Concentration (mg / L)Residue (g)Solvent Amount (L)Li2CO3 Content (mg)Li Content (g)Percentage (%)10,5410.99,4871.784510,860110,8602.045210,13094.350.858,6021.62418,426890.899,4671.78463,56988.640.82,8470.5314300840.744050.082------------------------

[0187]

[0188] Figure 4 is a graph of the leaching rate according to the high liquid ratio of the recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0189] Referring to the above [Table 4] and Fig. 4, when a solution with a high-liquid ratio of 1:10 was subjected to two-stage leaching, the leaching rate of lithium carbonate was evaluated to be over 98%. Therefore, the optimal lithium carbonate leaching rate was confirmed under the high-liquid ratio of 1:10 conditions through laboratory-scale tests using crushed / classified cell powder.

[0190] The present invention relates to a recovery system for dry recycling of waste secondary batteries capable of mass production of lithium carbonate and reduction of carbon dioxide, and a recovery method using the same.

[0191] That is, it was confirmed that mass production of lithium carbonate is possible under the conditions of a high-liquid ratio of 1:20 and a single-stage water leaching when applied to a pilot facility by utilizing the process conditions obtained through the above laboratory-scale test.

[0192]

[0193] <Example 1-6> Effect of reduced pressure distillation

[0194] The water-leached solution containing lithium carbonate obtained in Example 1-5 above was subjected to reduced pressure distillation.

[0195] FIG. 5 is a photograph of lithium carbonate obtained after reduced pressure distillation in a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0196] As shown in Fig. 5, after the water leaching solution was charged into the reactor, the inside of the reactor was depressurized to -0.1 Mpa, thereby obtaining lithium carbonate crystallized at an internal temperature of 55°C, and the recovery rate was 90% or more.

[0197]

[0198] <Example 1-7> Mass production of lithium carbonate

[0199] Using the raw material of Example 1-1 or 1-2, the cell powder obtained by passing through a #12 sieve was charged at 30 kg into the rotary kiln recovery system shown in Fig. 1, and then a large amount of lithium carbonate was obtained through a thermal decomposition process in an oxygen-free atmosphere with a carbon dioxide flow rate of 10 L / min.

[0200] Figure 6 is a result of analysis of the purity of lithium carbonate obtained by a recovery system and recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to one embodiment of the present invention.

[0201] FIG. 7 is a photograph of a prototype of lithium carbonate obtained in large quantities using a recovery system and recovery method for dry recycling of a lithium-ion battery capable of reducing carbon dioxide according to one embodiment of the present invention.

[0202] As illustrated in FIGS. 6 and 7, the pyrolysis product obtained through pyrolysis using a large amount of NCM-based cell powder contained 21.80 wt% lithium (Li), 0.01 wt% sodium (Na), 25.00 wt% oxygen (O), and 53.10 wt% loss on ignition, and the purity of lithium carbonate was confirmed to be 99.99%. Therefore, the mass production of lithium carbonate using low-grade waste secondary battery powder was possible through the recovery system and recovery method of the present invention, and lithium carbonate with a high purity of 99.7% or higher was obtained.

[0203]

[0204] <Example 1-8> Impact of carbon dioxide use generated from power plants

[0205] The raw material of Example 1-1 or 1-2 was used to pass through a #12 sieve to obtain cell powder, which was then charged into a tilting furnace, and a pyrolysis process was performed in an oxygen-free atmosphere with a flow rate of 60 L / min of carbon dioxide having a purity of 5% or less generated from a power plant (located in Incheon). The pyrolysis products obtained by performing the pyrolysis process at a temperature of 800 to 900°C for 1 to 5 hr were analyzed using an X-ray diffractometer (XRD).

[0206] Figure 8 is an X-ray diffraction diagram of a pyrolysis product obtained using carbon dioxide generated from a power plant in a recovery method according to one embodiment of the present invention.

[0207] As illustrated in Figure 8, a lithium carbonate (Li2CO3) phase was observed under the selected thermal decomposition reaction temperature and time conditions. Carbon dioxide gas generated on-site has problems such as low concentration, various impurities, and air mixing. However, the fact that lithium carbonate was produced even under these adverse conditions suggests that the carbon dioxide generated on-site can be utilized. Therefore, the present invention is considered a technology that can contribute to carbon neutrality and ensure economic feasibility.

[0208]

[0209] Above, although some examples have been given and various preferred embodiments of the present invention have been described, the description of the various embodiments described in the “Specific Details for Carrying Out the Invention” section is merely exemplary, and those skilled in the art to which the present invention pertains will readily understand that they can carry out various modifications of the present invention or carry out equivalent implementations of the present invention based on the above description.

[0210] In addition, since the present invention can be implemented in various other forms, the present invention is not limited by the above description, and the above description is provided only to make the disclosure of the present invention complete and to fully inform a person having ordinary skill in the art to which the present invention belongs of the scope of the present invention, and it should be understood that the present invention is defined only by each claim of the claims.

[0211] According to the present invention, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide emissions and using low-grade waste secondary battery powder is provided.

[0212] According to the present invention, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide and mass production of lithium carbonate is provided.

[0213] According to the present invention, a recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide is provided, which easily obtains a pyrolysis product containing lithium carbonate by pyrolyzing cell powder in an oxygen-free atmosphere under carbon dioxide conditions, which is a reducing atmosphere, and selectively recovers lithium carbonate therefrom.

[0214] According to the present invention, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide emissions and using low-grade waste secondary battery powder is provided.

[0215] According to the present invention, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide and mass production of lithium carbonate is provided.

[0216] According to the present invention, a recovery method for dry recycling of waste secondary batteries capable of reducing carbon dioxide is provided, in which cell powder is thermally decomposed in an oxygen-free atmosphere under carbon dioxide conditions as a reducing atmosphere as a dry process to easily obtain a thermal decomposition product containing lithium carbonate, and lithium carbonate is selectively recovered therefrom.

[0217]

[0218] 100: Recovery system 110: Process chamber

[0219] 102: Supply unit 112: Heating unit

[0220] 104: Hopper 114: First cooling section

[0221] 106: First valve 116: Second cooling unit

[0222] 108: Second valve 118: Discharge

Claims

1. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions. A supply unit including a hopper for supplying cell powder, a first valve for transporting the supplied cell powder, and a second valve for supplying carbon dioxide to the transported cell powder; A process chamber including a heating device for heating the cell powder in the provided carbon dioxide atmosphere, a first cooling unit for cooling the heated cell powder, and a second cooling unit for cooling the cell powder transferred from the first cooling unit; and It includes a discharge unit that discharges the cell powder transferred from the second cooling unit; The above system is characterized in that it is a rotary kiln system. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

2. In paragraph 1, The above cell powder is characterized in that it contains nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C). A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

3. In paragraph 1, The above cell powder is characterized in that the carbon (C) content is 29.5% or less. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

4. In paragraph 1, The above cell powder is characterized in that it contains at least one selected from boron (B), calcium (Ca), chromium (Cr), iron (Fe), potassium (K), magnesium (Mg), sodium (Na), phosphorus (P), titanium (Ti), zinc (Zn), zirconium (Zr), silicon (Si), fluorine (F), and nitrate (NO3). A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

5. In paragraph 1, The above cell powder is characterized in that the lithium (Li) content is 3 to 7 wt%. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

6. In paragraph 1, The above carbon dioxide is characterized in that it is either an industrial gas or a gas generated from a power plant. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

7. In paragraph 1, The temperature of the above heating device is characterized by being 800℃ to 1000℃. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

8. In paragraph 1, Characterized in that the flow rate of the carbon dioxide inside the process chamber is 10 to 12 L / min. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

9. In paragraph 1, The above rotary kiln is characterized in that it is operated under conditions of an angle of 10° or less and a rotation speed of 1 to 1.5 rpm. A recovery system for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

10. A recovery system for dry recycling of waste secondary batteries capable of reducing carbon dioxide according to any one of the first to ninth clauses, characterized in that it uses the same. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions. 11.(a) A step of thermally decomposing cell powder in an oxygen-free atmosphere under carbon dioxide conditions to obtain a thermal decomposition product containing lithium carbonate (Li2CO3); (b) a step of crushing / classifying the above pyrolysis product; (c) a step of separating the solid and liquid phases by leaching the above crushed / classified pyrolysis product; and (d) a step of obtaining the lithium carbonate by distilling the solution obtained as a liquid containing the lithium carbonate under reduced pressure; A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

12. In paragraph 11, The above carbon dioxide is characterized in that it is either an industrial gas or a gas generated from a power plant. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

13. In paragraph 11, The above cell powder is characterized in that it contains nickel (Ni), manganese (Mn), cobalt (Co), lithium (Li), aluminum (Al), copper (Cu), and carbon (C). A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

14. In paragraph 11, Step (a) above, Characterized in that it comprises a step of thermal decomposition in a temperature range of 800℃ to 1000℃. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

15. In paragraph 11, The above thermal decomposition product is characterized in that it contains at least one selected from nickel, manganese, cobalt and oxides thereof together with lithium carbonate. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

16. In paragraph 11, Step (b) above, characterized in that it comprises a step of crushing using a steel ball, A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

17. In paragraph 11, In the above step (c), The above water leaching process is characterized by being a high-liquid ratio 1:20, single-stage water leaching process. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

18. In paragraph 11, In the above step (d), the recovery rate of the lithium carbonate is characterized by being 90% or more. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

19. In paragraph 11, The purity of the lithium carbonate obtained in the above step (d) is characterized by being 99.7% or more. A recovery method for dry recycling of waste secondary batteries that can reduce carbon dioxide emissions.

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