High-temperature reduction device for waste battery recycling and heat treatment method for waste battery recycling

Abstract

The present invention relates to a high-temperature reduction device for waste battery reutilization and a heat treatment method for waste battery reutilization, the high-temperature reduction device comprising: a charging part for adding a raw material substance; a heating unit for heating the raw material added from the charging unit; the cooling part is used for cooling a product subjected to heat treatment; and a discharge part for discharging the cooled reactant from the cooling part, the heating part comprising: a preheating treatment part for preheating the raw material added from the charging part; and a high-temperature heat treatment unit for heating at a temperature higher than the temperature of the preheating unit, the high-temperature heat treatment unit including a heat treatment unit for heating at a temperature in the range of 1150 DEG C to 1400 DEG C.

Description

Technical Field

[0001] The present invention relates to waste batteries, and particularly to a high-temperature reduction device for waste battery reuse and a heat treatment method for waste battery reuse. Background Art

[0002] With the increasing global demand for electric vehicles, how to handle the waste batteries generated by these vehicles has become a social problem. For the main raw material substances of lithium secondary batteries as the waste batteries, they contain organic solvents, explosive substances, and heavy metal substances such as Ni, Co, Mn, and Fe, etc. However, Ni, Co, Mn, and Li have extremely scarce value as valuable metals, and the recycling and reuse processes after the abandonment of lithium secondary batteries have become an important research field.

[0003] For the conventional reuse of the waste batteries, a black powder (Black Powder) mixed with a positive electrode material and a negative electrode material is extracted through the processes of crushing, pulverizing, specific gravity screening, and magnetic screening of the waste batteries with exhausted life. For example, the black powder includes oxides of nickel, cobalt, manganese, lithium, aluminum, and oxygen as the positive electrode material and graphite and its mixture as the negative electrode material, and some impurities such as aluminum and copper, etc. The wet process and the dry process are mainly used as methods for recovering valuable metals from the black powder.

[0004] The wet process generates NiSO4, CoSO4, MnSO4, and Li2CO3 through leaching, solvent extraction, and lithium manufacturing. If the wet process is used to treat the black powder, the negative electrode material graphite included in the black powder will not dissolve in a strong acid environment, there is a problem of excessive consumption of the leaching process time, and there is also a problem of a decrease in the actual recovery rate due to the separation of the black powder and the graphite together.

[0005] However, the dry process is a process for removing aluminum in the slag through the high-temperature dry process of the black powder, and it may generate a Ni-Co-Mn-C alloy. For the dry process, at a high temperature (for example, 1400 °C to 1600 °C), the Ni-Mn-Li-Al-O oxides in the black powder are subjected to high-temperature reduction using graphite and blowing oxygen to generate CO or CO2 gas, so that the Ni-Co-Mn alloy and lithium and aluminum in the slag can be removed.

[0006] Then, the separated Ni-Co-Mn alloy can also go through the wet process. NiSO4, CoSO4, and MnSO4 are produced through the leaching-solvent extraction process in the wet process. Since it is a state where carbon is dissolved in the alloy, compared with the wet process, the leaching process time is reduced to about 70% of the level.

[0007] However, in the said process, not only valuable metals such as lithium and aluminum are consumed in the form of slag, but there is also a problem that lithium is not easily recovered. In addition, in the high-temperature dry process, since oxygen is blown into the added black powder to remove graphite, excessive carbon dioxide is generated, leading to environmental problems.

[0008] To solve the said environmental problems, it is necessary to study a non-oxidizing dry high-temperature smelting reduction process to minimize the generation of carbon dioxide and minimize the consumption of valuable metal lithium, and control the carbon content in the Ni-Co-Mn alloy below 10%. Summary of the Invention

[0009] Technical Problems to be Solved

[0010] According to an embodiment of the present invention, there is provided a non-oxidizing dry high-temperature reduction device for the reuse of waste batteries. The high-temperature reduction device for the reuse of waste batteries is environmentally friendly, and in terms of the recovery rate of valuable metals in subsequent processes, the best recovery rate of valuable metals can be ensured.

[0011] According to another embodiment of the present invention, there is provided a heat treatment method for the reuse of waste batteries, using the high-temperature reduction device having the aforementioned advantages.

[0012] Technical Solutions

[0013] The high-temperature reduction device for the reuse of waste batteries according to an embodiment of the present invention includes: a loading part for adding raw material substances; a heating part for heating the raw material substances added from the loading part; a cooling part for cooling the products after heat treatment; and a discharging part for discharging the cooled reactants from the cooling part. The heating part includes: a preheating treatment part for preheating the raw material substances added from the loading part; a high-temperature heat treatment part for heating at a temperature higher than that of the preheating treatment part. The high-temperature heat treatment part may include a heat treatment part for heat-treating the raw material substances in a temperature range of 1150°C to 1400°C. In one embodiment, the high-temperature heat treatment part may include two or more heat treatment parts in the vertical or horizontal direction.

[0014] In one embodiment, the high-temperature heat treatment part may include: an endothermic part for heating at a temperature higher than that of the preheating treatment part; and a melting part for heating in a temperature range higher than that of the endothermic part to form at least a part of a molten layer. In one embodiment, the heating part for temperature increase may increase the temperature of the raw material substances at a rate of 1°C / minute to 10°C / minute.

[0015] In one embodiment, the melting section can melt at least one of Ni, Cu, Co, and Mn to form spherical particles. In one embodiment, the weight ratio of carbon to nickel (C / Ni) in the charged raw material substances can be 20 or more.

[0016] In one embodiment, the heating section includes a heating furnace and a heating unit. When measuring the temperature at any position in the short-axis and long-axis directions of the cross-section of the heating furnace with reference to the central part, the temperature difference between the central part and the any position can be 250 °C or less. In one embodiment, the cross-section of the heating furnace can have a length ratio of the long axis to the short axis of 2 / 1 to 4 / 1.

[0017] In one embodiment, the heating furnace can have a bent portion on the outside of the heating furnace. In one embodiment, the length of the bent portion can be 30 mm or more. In one embodiment, the heating section includes at least one heating unit having a coil shape, and the intervals between the pitches of the coil can be narrower as the distance from the central region of the coil increases.

[0018] In one embodiment, the heating unit can be disposed on at least a part of the heating section. In one embodiment, the target temperature of the preheating section in the heating section can satisfy the following formula 1.

[0019] <Formula 1>

[0020] T 111 ≥0.813(x / (Cp×m)+25)

[0021] In the above formula 1, x is the input energy [W], Cp is the specific heat [J / Kg·°C], and m is the mass transfer rate [Kg / second].

[0022] The target temperature of the melting section in the heating section can satisfy the following formula 2.

[0023] <Formula 2>

[0024] T 113 ≥0.4(x / (Cp×m)+700)

[0025] In the above formula 2, x is the input energy [W], Cp is the specific heat [J / Kg·°C], and m is the mass transfer rate [Kg / second].

[0026] In one embodiment, the heating section may be carried out in an environment where the oxygen partial pressure is below 0.1 atmospheres. In one embodiment, in the heating section, the preheating section may be heated within a temperature range of 800 °C or below. In one embodiment, in the heating section, the endothermic section may undergo an endothermic reaction through the Boudouard Reaction in which CO2 gas is converted into 2CO.

[0027] According to another embodiment of the present invention, a heat treatment method for waste battery recycling, which is a heat treatment process carried out after the waste battery crushing process, includes: a loading step of adding a raw material substance; a heating step of heating the raw material substance added by loading; a cooling step of cooling the product after heat treatment; and a discharging step of discharging the cooled reactant. The step of heating the raw material substance includes: a preheating step of preheating the raw material substance added by loading; a high-temperature heat treatment step of heating at a temperature higher than that of the preheating step. The high-temperature heat treatment step may include a heat treatment step of performing heat treatment on the raw material substance within a temperature range of 1150 °C to 1400 °C.

[0028] In one embodiment, the high-temperature heat treatment step may include: an endothermic step of heating at a temperature higher than that of the preheating section; a melting step of heating within a temperature range higher than that of the endothermic step to form at least a part of a molten layer.

[0029] In one embodiment, in the step of heating the raw material substance added by loading, when measuring the temperature at any position in the short-axis and long-axis directions of the cross-section of the heating furnace of the heating component with reference to the central part, the temperature difference between the central part and the any position may be 250 °C or below.

[0030] In one embodiment, the cross-section of the heating furnace may have a length ratio of the long axis to the short axis of 2 / 1 to 4 / 1. In one embodiment, the heating furnace may have a bent portion on the outside of the heating furnace.

[0031] In one embodiment, the length of the bent portion may be 60 mm or more. In one embodiment, the step of preheating the raw material substance added by loading may be carried out at the target temperature of the following formula 1.

[0032] <Formula 1>

[0033] T111≥0.813(x / (Cp×m)+25)

[0034] In the above formula 1, x is the input energy [W], Cp is the specific heat [J / Kg·℃], and m is the mass transfer amount [Kg / second].

[0035] In one embodiment, in the temperature range higher than the endothermic step, the target temperature of the melting step for forming at least a part of the molten layer may satisfy the following formula 2.

[0036] <Formula 2>

[0037] T113≥0.4(x / (Cp×m)+700)

[0038] In the above formula 2, x is the input energy [W], Cp is the specific heat [J / Kg·℃], and m is the mass transfer amount [Kg / second].

[0039] Beneficial effects

[0040] According to an embodiment of the present invention, a dry high-temperature reduction device is provided. The high-temperature reduction device for waste battery reuse controls the temperature at the first to third regions in the heating part, and along with the structural features in the heating part, it is environmentally friendly and can ensure the best recovery rate of valuable metals in terms of the recovery rate of valuable metals in subsequent processes.

[0041] Another embodiment of the present invention provides a heat treatment method for waste battery reuse, using the high-temperature reduction device with the aforementioned advantages. Description of the drawings

[0042] Figure 1a Showing a high-temperature reduction device for waste battery reuse according to an embodiment of the present invention, Figure 1b Showing a high-temperature reduction device according to another embodiment of the present invention.

[0043] Figures 2a to 2c Showing a photograph of the particle size formation of an alloy based on the C / Ni content of a raw material substance according to an embodiment of the present invention.

[0044] Figures 3a to 3c Showing the shapes of reactants according to embodiments and comparative examples of the present invention, Figure 3d Showing the heating rate and edge distribution according to a comparative example of the present invention.

[0045] Figure 4 Showing the actual yield of reactants based on temperature according to embodiments and comparative examples of the present invention.

[0046] Figure 5 Showing an arbitrary position in the cross-section of a heating furnace according to an embodiment of the present invention with reference to the central position.

[0047] Figure 6Shows the temperature deviation in the heating furnace according to an embodiment and a comparative example of the present invention.

[0048] Figure 7 Shows the temperature deviation in the heating furnace according to an embodiment and a comparative example of the present invention.

[0049] Figure 8a Is a graph showing the tendency of temperature deviation reduction in the heating furnace based on the length of the bent portion according to an embodiment of the present invention, Figure 8b Shows the temperature deviation based on the length of the bent portion measured by thermal desorption simulation.

[0050] Figures 9a to 9c Shows the coil configurations and their corresponding temperature distributions according to the comparative example and the embodiment of the present invention. Detailed Description

[0051] The terms first, second, third, etc. are used to describe various parts, components, regions, layers, and / or segments, but these parts, components, regions, layers, and / or segments should not be limited by these terms. These terms are only used to distinguish one part, component, region, layer, and / or segment from another part, component, region, layer, and / or segment. Therefore, without departing from the scope of the present invention, the first part, component, region, layer, and / or segment described below can also be described as the second part, component, region, layer, and / or segment.

[0052] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Unless clearly stated to the contrary in the context, the singular forms used herein are also intended to include the plural forms. The term "comprising" used in the specification can specifically refer to a certain feature, field, integer, step, action, element, and / or component, but does not exclude the existence or addition of other features, fields, integers, steps, actions, elements, and / or components.

[0053] If a part is described as being above another part, there may be other parts directly above or between the other part. If a part is described as being directly above another part, there will be no other parts in between.

[0054] Although not otherwise defined, the meanings of all terms (including technical terms and scientific terms) used herein are the same as those commonly understood by those of ordinary skill in the art to which the present invention pertains. For terms defined in a dictionary, they should be interpreted as having a meaning consistent with the relevant technical literature and the content disclosed herein, and should not be interpreted in an idealized or overly formal sense.

[0055] Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are given only as examples, and the present invention is not limited to the following embodiments. The present invention is only defined by the scope of the claims.

[0056] Figure 1a Shows a high-temperature reduction device for waste battery recycling according to an embodiment of the present invention.

[0057] Referring to Figure 1a , the high-temperature reduction device 10 for waste battery recycling according to an embodiment of the present invention includes: a charging unit 100 for adding raw material substances; a heating unit 110 for heating the raw material substances added from the charging unit 100; a cooling unit 120 for cooling the heat-treated product; and a discharging unit 130 for discharging the cooled reactants from the cooling unit 120. The high-temperature reduction device 10 of the present invention refers to the heating furnace used in the step of adding battery crushed materials into a heating furnace (Furnace) heated to a high temperature to raise the temperature of the battery crushed materials above the melting point.

[0058] The high-temperature reduction device 10 can be used to crush waste batteries, and perform high-temperature reduction on the waste battery crushed materials that have undergone specific gravity screening, magnetic screening, or classification screening as needed, so as to manufacture reactants containing oxides of nickel, cobalt, manganese, lithium, aluminum, or oxygen as the positive electrode material, graphite and its mixtures, and some impurities such as aluminum and copper as the negative electrode material.

[0059] The charging unit 100 is a component for adding raw material substances, and the raw material substances can be the waste battery crushed materials as described above. The waste battery crushed materials refer to the substances that are the base materials of the battery crushed materials or the materials that have been completely crushed. The base materials of the battery crushed materials can include batteries with exhausted life, waste batteries, and scraps generated in the manufacturing process of lithium-ion batteries.

[0060] Specifically, the waste batteries can include the positive electrode materials constituting the waste batteries, such as scraps, jellyroll structures, and slurries, defective products generated in the manufacturing process, residues in the manufacturing process, and the generated scraps. The base materials of the battery crushed materials can then be made into battery crushed materials through a crushing process. The completely crushed materials themselves can be the completely crushed products such as black powder, etc. As described above, by recycling waste batteries to manufacture battery crushed materials, environmental and economic advantages can be achieved.

[0061] In one embodiment, the weight ratio of C / Ni in the raw material substance may be 20 or more. The weight ratio of C / Ni specifically refers to the value obtained by dividing the weight percentage of carbon by the weight percentage of nickel. In one embodiment, by the weight ratio of C / Ni in the raw material substance satisfying the foregoing range, the size of the powder particles becomes smaller, and in subsequent processes, a spherical reactant in the optimal particle size ratio for acid treatment, i.e., in the range of 500 μm to 3000 μm, can be formed. If the weight ratio of C / Ni in the raw material substance exceeds the foregoing range, it is difficult to form spherical fragments, and there is a problem that the reduction caused by carbon cannot be fully carried out due to the formation of massive reactants.

[0062] In one embodiment, the loading unit 100 may further include a pusher. The pusher may be a component for making the addition of the raw material substance loaded through the loading unit 100 smoother.

[0063] The heating unit 110 is a component for heating the raw material substance added from the loading unit 100. The heating unit 110 can add a raw material substance such as a waste battery fragment to a heating furnace capable of raising the temperature to a high temperature to raise the temperature of the waste battery fragment to a temperature above the melting point. As described above, through the heating unit 110, an Ni-Co-Mn alloy containing valuable metals and Li oxide can be produced, and thus the valuable metals can be recovered in subsequent processes.

[0064] In one embodiment, the heating unit 110 may be characterized in that the raw material substance added from the loading unit 100 is heated at a heating rate of 1 °C / minute to 10 °C / minute. Specifically, the heating rate may be in the range of 2.0 °C / minute to 5.0 °C / minute.

[0065] In one embodiment, the heating unit 110 may be carried out in a temperature range of 800 °C to 1300 °C. Due to heating in the heating rate and the temperature range, an Ni-based alloy is formed in the form of spherical particles of 100 μm to 3000 μm, thereby improving the recovery rate of valuable metals and Li.

[0066] Specifically, the heating unit 110 may include at least one induction coil. Specifically, the heating unit 110 may include one induction coil, and more induction coils may be used. In Figure 1a this case, the preheating treatment unit 111 uses one induction coil, and the heat absorption unit 112 and the melting unit 113 use additional induction coils.

[0067] In one embodiment, the heating unit 110 may include a preheating unit 111 for preheating the added raw material substance and a high-temperature heat treatment unit (not shown in the figure) for heating at a temperature higher than that of the preheating unit 111. The high-temperature heat treatment unit may be a high-temperature reduction unit, which is a component for heating at a temperature higher than that of the preheating unit 111 to reduce the raw material substance. In one embodiment, the high-temperature heat treatment unit may include two or more heat treatment units in the vertical or horizontal direction.

[0068] In one embodiment, the high-temperature heat treatment unit may include: an endothermic unit 112; and a melting unit 113 for heating within a temperature range higher than that of the endothermic unit 112 to form at least a part of a molten layer. The heating unit 110 includes sections with different temperatures, thus having the advantage of being able to improve the recovery rate of valuable metals.

[0069] The preheating unit 111 may be heated within a temperature range of 800 °C or lower. Specifically, the preheating unit 111 may be heated within a temperature range of 700 °C or lower. The main purpose of the preheating unit 111 is to preheat the crushed waste battery of the raw material substance within the aforementioned range to remove the electrolyte and separator of the crushed waste battery.

[0070] The endothermic unit 112 may be heated within a temperature range higher than that of the preheating unit 111. Specifically, an endothermic reaction may occur within a range of 700 °C to 1200 °C, more specifically within a range of 700 °C to 900 °C, and more specifically within a range of 800 °C to 900 °C. Specifically, the endothermic unit 112 may undergo an endothermic reaction through the Boudouard Reaction in which CO2 gas is converted into 2CO gas within the aforementioned temperature range. By including the endothermic unit 112, the high-temperature reduction device 10 can reduce carbon dioxide, thus having the advantage of environmental protection.

[0071] The melting unit 113 may be heated within a temperature range higher than that of the endothermic unit 112. Specifically, it may be heated within a temperature range of 1400 °C or lower, and more specifically within a temperature range of 1150 °C to 1400 °C or lower. In this melting unit 113, any one of the metal substances of nickel, cobalt, manganese, and copper is melted, so that it can be configured in a spherical form. The melting unit 113 is the highest high-temperature reaction section within the heating unit 110 and is a component for performing heat treatment within the aforementioned temperature range so as to be able to produce a Ni-Co-Mn alloy containing valuable metals and Li oxide.

[0072] Specifically, due to the heat treatment within the aforementioned temperature range, the melting section 113 is a section where the crushed materials obtained by reducing the positive electrode, negative electrode, or separator in a stacked form are reduced into spherical particles (Droplets) that are easily reactive in subsequent processes such as hydrometallurgical processes for extracting valuable metals.

[0073] Since the melting section 113 is heated within the aforementioned temperature range, the Li recovery rate satisfies 40% to 70%, specifically, it can satisfy the range of 55% to 60%. The Ni-Co-Mn alloy satisfies 55% to 95%, specifically, it can satisfy 85% to 95%, and more specifically, it can satisfy the range of 85% to 90%. For the melting section 113, if it exceeds the upper limit value of the aforementioned range, there is a problem of too low Li recovery rate. If it exceeds the lower limit value of the aforementioned range, there is a problem of too low recovery rate of the Ni-Co-Mn alloy. As described above, for the melting section 113, due to being carried out within the aforementioned temperature range, it has the advantages of improving the recovery rate of the Ni-Co-Mn alloy and at the same time being able to improve the recovery rate of Li.

[0074] In one embodiment, the heating section 110 includes a heating furnace 110_F and a heating unit 110_H. The heating furnace 110_F refers to the passage through which the added raw material substances pass through the heating section 110. The heating unit 110_H is a component that applies heat energy to the heating furnace 110_F.

[0075] For the heating furnace 110_F, when measuring the temperature at any position in the short-axis and long-axis directions of the cross-section of the heating furnace 110_F with reference to the central part, the temperature difference between the central part and the any position can be 250°C or less. The cross-section of the heating furnace 110_F refers to the cross-section cut along a direction different from the advancing direction of the raw material substances, such as a cross or a direction perpendicular thereto.

[0076] Specifically, the temperature difference can be the difference between the maximum temperature and the minimum temperature. If the temperature difference between the central part and the any position exceeds the temperature range, it is not easy to achieve uniform heat transfer in the heating furnace 110_F, and there is a problem of a decrease in the recovery rate of valuable metals.

[0077] In one embodiment, in the cross-section of the heating furnace 110_F, when taking 100% of a circular cross-section with the same area as a reference, the temperature deviation between the central part and the any position can be less than 10%. Specifically, the temperature deviation between the central part and the any position can be as low as 20% or less (counted as 100%). For a detailed description of this, refer to the following Figure 4 。

[0078] In one embodiment, the cross-section of the heating furnace 110_F may have a ratio of the length of the major axis to the length of the minor axis of 2 / 1 to 4 / 1. Specifically, the ratio of the length of the major axis to the length of the minor axis may be 2.5 / 1 to 3.5 / 1.

[0079] By having the ratio of the length of the major axis to the length of the minor axis within the aforementioned range, the temperature range deviation within the heating furnace 110_F is relatively low, and it has the advantage of being able to transfer heat evenly. If the ratio of the length of the major axis to the length of the minor axis exceeds the aforementioned range, the temperature range deviation within the heating furnace 110_F is relatively high, and it is difficult to transfer heat evenly. Therefore, there is a problem of relatively low recovery rate of valuable metals in the reactants.

[0080] In one embodiment, the heating furnace 110_F may have a bent portion on the outer side of the heating furnace 110_F. In the cross-section of the quadrilateral-shaped heating furnace 110_F, the bent portion refers to a shape with the corner portions bent. The bent portion can prevent heat energy from concentrating on the corner portions, thereby avoiding the problem that the actual yield of the reactants is relatively low at the corner portions in the conventional quadrilateral-shaped heating furnace 110_F.

[0081] In one embodiment, the length of the bent portion may be 60 mm or more. Specifically, the length of the bent portion may be 60 mm or more and 110 mm or less, and more specifically, it may be 75 mm or more and 100 mm or less. The length of the bent portion refers to the radius when drawing a central circle based on the corner portion of the heating furnace. For a detailed description thereof, refer to the following Figure 8a and Figure 8b 。

[0082] In one embodiment, at least one or more heating units 110_H are included within the heating section 110. The heating unit 110_H can apply heat energy by methods such as induction heating, gas heating, or resistance heating. In one embodiment, the heating unit 110_H may have a coil shape as a means for supplying the heat energy. In one embodiment, as a non-limiting example, the wire of the coil may have any one of a circular, square, rectangular, oval, triangular, trapezoidal, rhombic, and star-shaped cross-section.

[0083] In one embodiment, for the coil of the heating unit 110_H, the distance between the coil pitches may become narrower as it gets farther from the central region of the coil. The central region of the coil refers to the region including the intermediate value when the coil is wound in the length direction. The pitch of the coil refers to the distance between two effective coil sides when the coil is wound.

[0084] For induction heating, the inductance of the coil is proportional to the number of turns of the coil. Specifically, the inductance of the coil is proportional to the number of times the coil is wound. Specifically, if the number of times the coil is wound is large, the thermal energy applied is high, and if the number of times the coil is wound is small, the thermal energy applied is low.

[0085] Using such a principle, the coil of the heating unit 110_H of the present invention is such that the interval distance between the pitches of the coil becomes narrower as it gets farther from the central region of the coil, and thus has the advantage of dispersing the heat in the central region where the conventional thermal energy is concentrated. In one embodiment, the heating units 110_H are respectively arranged in the preheating treatment unit 111, the heat absorption unit 112, and the melting unit 113, and the temperature of the heating unit 110 can be controlled.

[0086] The heating unit 110 can be heated in a gas environment containing oxygen, and the oxygen may include 5% by volume or less. In one embodiment, the heating unit 110 can be heated in an environment where the oxygen partial pressure is 0.1 atm or less. Since heating is performed in a gas environment containing some oxygen within the aforementioned range, lithium oxide for recovering lithium is easily formed, and the recovery rate of valuable metals can be increased.

[0087] In one embodiment, the preheating treatment unit 111 in the heating unit 110 can be performed at a power of 12.0 kW or more. Specifically, the preheating treatment unit 111 can be performed at a power of 12.0 kW to 15.0 kW. Specifically, the power can be a power of 12.0 kW to 14 kW.

[0088] In one embodiment, the melting unit 113 in the heating unit 110 can be performed at a power of 16.0 kW or more. Specifically, the power can be in the range of 16.0 kW to 19.0 kW. Specifically, the power can be a power of 17.5 kW to 18.5 kW.

[0089] The power applied in the preheating treatment unit 111 and the melting unit 113 can represent the minimum energy required to heat the reactants, and by satisfying the range with the power, heat treatment can be performed within the target temperature range.

[0090] In one embodiment, the residence time of the reactants in the heating unit 110 can be 5 hours to 7 hours. The residence time can be expressed as the value obtained by dividing the total length of the heating unit 110 by the moving distance of the reactants per hour. For example, in the heating unit 110 that generates reactants at 65 kg / h, if the length of the heating unit 110 is 285 cm and the reactants move about 44 cm per hour, the reactants pass through after staying in the heating unit 110 for about 6.5 hours.

[0091] If it is carried out within the residence time in the heating unit 110, it has the advantage of improving the recovery rate of valuable metals such as Li, Ni, Co, and Mn in the heating unit 110. If the residence time exceeds the aforementioned range, not only will there be a loss of Li, but there will also be a problem that the particle size of the reduced valuable metals becomes larger, resulting in a longer leaching time in the subsequent process.

[0092] In one embodiment, the target temperature of the preheating unit 111 in the heating unit 110 can satisfy the following formula 1.

[0093] <Formula 1>

[0094] T 111 ≥0.813(x / (Cp×m)+25)

[0095] In the above formula 1, x is the input energy [W], Cp is the specific heat [J / Kg·°C], and m is the mass transfer rate [Kg / second].

[0096] In one embodiment, the target temperature of the melting unit 113 in the heating unit 110 can satisfy the following formula 2.

[0097] <Formula 2>

[0098] T 113 ≥0.4(x / (Cp×m)+700)

[0099] In the above formula 2, x is the input energy [W], Cp is the specific heat [J / Kg·°C], and m is the mass transfer rate [Kg / second].

[0100] The above formula 1 and formula 2 specifically represent the minimum values of the target temperatures of the preheating unit 111 and the melting unit 113 in the heating unit 110 and the supply energy of the added reactants. By inputting the minimum energy of the above formula 1 and formula 2, the target temperatures of the preheating unit 111 and the melting unit 113 can be achieved. In one embodiment, x in the above formula 1 can be 12000 W or more. In one embodiment, x in the above formula 2 can be 16000 W or more.

[0101] By controlling the target temperature based on the supply energy of the reactants as shown in the above formula 1 and formula 2, it has the advantage of improving the recovery rate of valuable metals such as Li, Ni, Co, and Mn. If heating is carried out within a temperature range exceeding the above formula 1 and formula 2, there will be a problem of a decrease in the recovery rate of valuable metals.

[0102] The cooling unit 120 includes a step of cooling the reactant generated by the heating unit 110 to below 100°C. The reactant may be a reduction reaction substance generated by the heating unit 110. Since the cooling unit 120 cools within the aforementioned range, the reactant heated in the heating unit 110 can be stabilized.

[0103] The discharging unit 130 is a component that discharges the reactant containing valuable metals cooled by the cooling unit 120. The reactant containing valuable metals may be composed of a Ni-Co based alloy, a lithium compound, carbon, and other residual impurities. The impurities may include, for example, impurities such as Al, Cu, P, Na, Mg, and F.

[0104] In one embodiment, the reactant recovered by the high-temperature reduction device 10 from the raw material substance may account for more than 60% of the total raw material substance. Specifically, the weight of the waste battery crushed material before being added to the heating furnace may have a recovery rate of 60% to more than 65% of the reactant after heat treatment. In one embodiment, Ni-Co in the reactant after heat treatment may account for more than 40% of the total weight.

[0105] The high-temperature reduction device 10 may include a magnetic screening unit that magnetically screens the alloy recovered after cooling. The magnetic screening unit may be disposed within the discharging unit 130 or may be separately disposed from the discharging unit 130.

[0106] In one embodiment, the magnetic screening unit may magnetically screen the Ni-Co based alloy with a magnetic force of 100 gauss or more. By magnetically screening with a magnetic force of 100 gauss or more, the magnetic Co-based alloy can be separately separated, thereby increasing the recovery rate of the valuable metal alloy.

[0107] In one embodiment, the discharging unit 130 may further include a stepper. For example, the stepper is a component having an elastic force and can be used as a means to make the amount of the reactant discharged from the discharging unit 130 more precise and easier to discharge.

[0108] In one embodiment, the high-temperature reduction device 10 may further include at least one suction unit. The suction unit may be a component for controlling the gas concentration and heat in the heating furnace and for ventilation. For example, the suction unit may be disposed in the front-end component of the heating unit 110, i.e., the feeding unit, or in the rear-end component of the heating unit 110, i.e., the section of the cooling unit 120.

[0109] Figure 1b Fig. 10' shows a high-temperature reduction device according to another embodiment of the present invention.

[0110] Refer to Figure 1b and Figure 1aDifferently, the high-temperature reduction device 10” can also be implemented in the form of a horizontal furnace instead of a vertical furnace, and the structure of the high-temperature reduction device 10’ is the same within the scope not conflicting with the foregoing description.

[0111] According to another embodiment of the present invention, a high-temperature reduction method for waste battery recycling, which is a heat treatment process carried out after the waste battery crushing process, may include: a charging step of adding a raw material substance; a heating step of heating the raw material substance added by charging; a cooling step of cooling the heat-treated product; and a discharging step of discharging the cooled reactant.

[0112] In one embodiment, the step of heating the raw material substance can be carried out by the heating unit 110 of the aforementioned high-temperature reduction device 10, and the detailed description thereof is the same within the scope not conflicting with the foregoing description.

[0113] The step of heating the raw material substance may include: a preheating step of preheating the raw material substance added by charging; a high-temperature heat treatment step of heating at a temperature higher than that of the preheating step.

[0114] In one embodiment, the high-temperature heat treatment step may include: the endothermic step; and a melting step of heating within a temperature range higher than that of the endothermic step to form at least a part of a molten layer. The preheating step, the endothermic step, and the melting step can be respectively carried out by the preheating unit 111, the endothermic unit 112, and the melting unit 113 of the aforementioned high-temperature reduction device 10, and the detailed description thereof is the same within the scope not conflicting with the foregoing description.

[0115] The step of cooling the heat-treated product can be carried out by the cooling unit 120 of the aforementioned high-temperature reduction device 10, and the detailed description thereof is the same within the scope not conflicting with the foregoing description.

[0116] The step of discharging the cooled reactant can be carried out by the discharging unit 130 of the aforementioned high-temperature reduction device 10, and the detailed description thereof is the same within the scope not conflicting with the foregoing description.

[0117] The preferred embodiments and comparative examples of the present invention are described below. However, the following embodiments are only a preferred embodiment of the present invention, and the present invention is not limited to the following embodiments.

[0118] <Experimental Example>

[0119] <Conditions of the raw material substance added in the charging part>

[0120] The crushed material loaded through the charging part 100 of the present application invention uses a raw material substance satisfying the following described composition and component ratio.

[0121]

Table 1

[0122]

[0123] Referring to Table 1 above, the crushed material component data is a composition table of waste battery crushed material used as an example for NCM622. In the battery crushed material, Ni-Co-Mn is in the form of an oxide combined with oxygen. In order to reduce it, it is necessary to react with C in the crushed material. Therefore, it has been confirmed that the C / Ni ratio needs to be restricted from the initial battery raw materials. Table 2 below is the evaluation result of the alloy size generated based on the C / Ni content.

[0124]

Table 2

[0125]

[0126]

[0127] Figures 2a to 2c Shows a photograph of the grain size formation of an alloy based on the C / Ni content of a raw material substance according to an embodiment of the present invention. Figures 2a to 2c Sequentially represent the grain size formation data of the alloy when the C / Ni ratio is 100, 20, and 5 respectively. In Figures 2a to 2c , the process temperature is 1250 °C, the average size of the crushed material is 20 mm, the holding time above 1050 °C is 60 minutes, and the oxygen is kept below 0.5%. Then only the C / Ni ratio is controlled. As Figure 2c shown, when the C / Ni ratio is less than 5, lumps of more than 5000 μm are presented. As Figure 2a and Figure 2b shown, when the C / Ni is 20 or more, particulate shapes such as powders are presented.

[0128] Specifically, it has been confirmed that the higher the C / Ni, the smaller the size of the powder particles. In the subsequent process, for acid treatment, the optimal grain size ratio is 75 μm to 3000 μm. Therefore, the C / Ni ratio of the raw material substance in the present invention is preferably 20 or more. If the ratio is less than 20, the C content in the crushed material is too small. Even if a Ni-based alloy is formed, due to the wettability caused by C, it is difficult to form spherical crushed materials of less than 3000 μm, but blocky reactants are formed, and there is a problem that the reduction caused by C cannot be completely carried out.

[0129] Figure 2d Shows the XRD data of the reduced reactant according to the comparative example of the present invention.

[0130] Referring to Figure 2d , Figure 2dXRD data of the reactants reduced when the weight ratio of C / Ni is 20 or less are shown. In this case, some substances are not reduced, and a part of Ni in the base substance remains in the form of NiO.

[0131] <Temperature rise amount at the center of the heating furnace interior and shape of reactants based on temperature conditions>

[0132] Figures 3a to 3c The shapes of the reactants according to the examples and comparative examples of the present invention are shown. Figure 3d The heating rate and edge distribution according to the comparative example of the present invention are shown.

[0133] Figure 3a The shape of the reactant formed when the temperature at the center of the heating furnace interior is a low temperature of 1150 °C or less and the heating rate is 3 °C / min is shown. Figure 2b The shape of the reactant formed when the temperature at the center of the heating furnace interior is raised from about 1200 °C at a heating rate of 1 °C / min is shown. Figure 2c The shape of the reactant formed when the temperature at the center of the heating furnace interior is raised from about 1250 °C at a heating rate of 3 °C / min is shown.

[0134] Refer to Figure 3a , at a low temperature of 1150 °C or less at the center of the heating furnace interior, the NCM alloy and the internal Li-Al-O formation aggregate and exist in the form of flakes of 3000 μm or more. In this case, it is not easy to separate and recover NCM and Li-Al-O.

[0135] Refer to Figure 3b and Figure 3c , when the temperature at the center of the heating furnace interior is the melting temperature of Cu or Ni, i.e., 1150 °C to 1400 °C, it has been confirmed that the flakes exist in the form of powder or spherical alloy.

[0136] Specifically, refer to Figure 3b , in this case, when the temperature is raised from 1200 °C or less at a heating rate of 1 °C / min or less, it has been confirmed that it does not form into a sphere from the flake, but forms into a powder of 100 μm or less.

[0137] At this time, after NCM and Li-Al-O coexist, Li-Al-O stays as an oxide for a long time and breaks into smaller sizes. At this time, it is considered that NCM sticks together and exists. Therefore, NCM cannot aggregate and exists in the form of powder. When the NCM exists in the form of powder, there is a problem that C or Li-Al-O particles are screened together in the subsequent magnetic screening process, which leads to a decrease in the actual yield.

[0138] Refer to Figure 3c, when the temperature at the center of the heating furnace is 1250 °C and the heating rate is 10 °C / min or less, specifically about 3 °C / min, it has been confirmed that Ni-based alloys are formed in the form of spherical particles with a size of 100 μm to 3000 μm.

[0139] Refer to Figure 3d It has been confirmed that when the heating rate is 10 °C / min or more, high power is required, and there is a problem that the temperature at the bent part of the heating part rises to 1400 °C or more. As described above, in the preheating treatment part and the high-temperature heat treatment part of the present invention, the heating rate can meet the foregoing content. Specifically, the heating rate of the internal temperature of the heat treatment center part within the range of 700 °C to 1250 °C can meet the foregoing range.

[0140]

[0141] Figure 4 Shows the actual yields of reactants based on temperature for the examples and comparative examples of the present invention.

[0142] Refer to Figure 4 , which shows the actual yields of Ni-Co-Mn and LiAlO2 based on temperature. It has been confirmed that the actual yields of Ni-Co-Mn and LiAlO2 are both excellent within the range of 1100 °C to 1500 °C, specifically within the range of 1200 °C to 1300 °C. It has been confirmed that there is a problem of excessive decrease in the actual yield of LiAlO2 within the range of 1500 °C or more and a problem of excessive decrease in the actual yield of Ni-Co-Mn within the range of 1100 °C or less.

[0143] The substances generated by heating in the high-temperature reduction device of the present invention will affect the recovery rates of the main constituent substances, namely the Ni-Co-Mn alloy and Li, according to the temperature conditions, particularly the temperature conditions in the foregoing melting part or melting step.

[0144] Table 3 below shows the lithium recovery rate and NC alloy recovery rate according to the temperature conditions of the melting part.

[0145]

Table 3

[0146] Temperature [°C] Li Recovery Rate [%] NCM Alloy Recovery Rate [%] Remarks 1,100 80 5 Comparative Example 1150 70 55 Example 1200 60 85 Example 1300 55 90 Example 1400 40 95 Example 1,500 15 95 Comparative Example

[0147] Refer to Table 3 and confirm that when the temperature in the melting part or melting step is in the range of 1150 °C to 1400 °C, specifically in the range of 1200 °C to 1300 °C, not only is the recovery rate of the valuable metal NCM alloy excellent, but also the recovery rate of Li is excellent.

[0148] <Temperature deviation by position in the cross-section of the heating furnace>

[0149] Figure 5Shows an arbitrary position in the cross-section of a heating furnace according to an embodiment of the present invention with reference to the central position.

[0150] Reference Figure 5 , which shows the temperature T(X, Y) at arbitrary positions (X, Y) with reference to the central position (O) in the cross-section of the heating furnace. Specifically, the cross-section of the heating furnace refers to the cross-section cut along a direction perpendicular to the advancing direction of the raw material substance.

[0151] Since it is heated by the external heating element, the temperature at the central part is the lowest in the cross-section of the furnace, while the temperature is the highest at the periphery of the furnace closest to the heating element. The shape of a conventional furnace is most commonly a circular shape, but in the furnace shape design of the present invention, by adjusting the length ratio of the transverse and longitudinal directions of the heating furnace, a ratio showing the minimum temperature deviation is proposed.

[0152] Figure 6 Shows the temperature deviation in the heating furnace according to an embodiment and a comparative example of the present invention.

[0153] Reference Figure 6 , when assuming that the temperature deviation of a circular shape is 100%, the length ratio of the transverse and longitudinal directions of the heating furnace represents the change in temperature deviation according to the length ratio in the major axis direction (X) and minor axis direction (Y) under the same area. Specifically, when the cross-section of the heating furnace is a quadrilateral shape, if the length ratio in the minor axis direction decreases compared to the length ratio in the major axis direction, the temperature deviation should gradually decrease, but the temperature is higher at the corners of the corner parts, and there is a problem of reduced yield of the reactants at the corners.

[0154] Figure 7 Shows the temperature deviation in the heating furnace according to an embodiment and a comparative example of the present invention.

[0155] Reference Figure 7 It is confirmed that when the length ratio of the major axis to the minor axis of the cross-section of the heating furnace is 3:1, the corners of the outer side of the heating furnace have a bent portion with a predetermined angle instead of a sharp shape, thereby preventing heat concentration at the corners. Therefore, for a heating furnace with a length ratio of the major axis to the minor axis of the cross-section including the bent portion of 3:1, it has been confirmed that the temperature deviation is lower compared to the circular shape.

[0156] Figure 8a Is a graph showing the decreasing trend of the temperature deviation in the heating furnace based on the length of the bent portion according to an embodiment of the present invention, Figure 8b Shows the temperature deviation based on the length of the bent portion measured by thermal analysis simulation.

[0157] Reference Figure 8aIt can be confirmed that as the length of the bent portion increases, the temperature deviation decreases. Specifically, when the length of the bent portion is 60 mm or more, specifically 80 mm or more, and more specifically 100 mm or more, the temperature difference between the outer periphery and the central portion tends to be 200 °C.

[0158] Refer to Figure 8b It can be confirmed that when the length of the bent portion is 50 mm or less, heat is concentrated near the bent portion. When the length of the bent portion is 100 mm, there is a uniform heat distribution in the heating furnace, and there is no area where heat is concentrated near the bent portion.

[0159] <Pitch interval of the control coil in induction heating>

[0160] Figures 9a to 9c Shows the coil configurations and their corresponding temperature distributions of the comparative examples and embodiments according to the present invention.

[0161] Refer to Figure 9a It is confirmed that when induction heating is used as the heating unit for applying heat to the heating furnace in the heating portion, the average temperature in the heating furnace is different according to the interval between the pitches of the coils used for induction heating. Specifically, it has been confirmed that the average temperature reaches the highest temperature in the central region of the coil.

[0162] Refer to Figure 9b It can be confirmed that the farther the coil is from the central portion of the heating furnace, the narrower the pitch interval of the coil. Specifically, when comparing the central region and the outer peripheral region of the coil, it can be confirmed that the pitch interval of the coil at the outer peripheral region is dense.

[0163] As described above, the pitch interval of the coil is dense in the outer peripheral region and not very dense in the central region. Therefore Figure 9a the heat flow concentration causes the temperature in the central region with a relatively high average temperature to disperse to the outer peripheral region, and the difference in the average temperature between the central region and the outer peripheral region is small, and a uniform temperature can be heated.

[0164] Refer to Figure 9c It is confirmed that in the preheating treatment portion, the heat absorption portion, and the melting portion of the heating unit configured in the present invention, as Figure 9b shown, controlling the pitch interval of the coil as the heating unit has different modes in the central region and the outer peripheral region, thereby preventing the problem of a large difference in the average temperature of the heating portion.

[0165] <Energy required for the heating element - The minimum energy for controlling the target temperature of the heating portion>

[0166] In order to reach the target temperature Y (preheating section of the heating unit: 700 °C, melting section: 1150 °C to 1400 °C) of the reactants moving 65 kg per hour in the heating section, the required energy supplied by the heating element (preheat treatment section: 12 kW, melting section: 18 kW) needs to be satisfied to reach the required target temperature. The following formula represents the correlation between the minimum energy required by the heating element during the heating furnace temperature rise and the target temperature. Here, a is a constant regarding efficiency. At temperatures below 700 degrees before the start of the Boudouard reaction, this constant is below 1, and at target temperatures above the Boudouard reaction temperature, this constant changes to 0.4. This has a coefficient ranging from 0.2 to 1 according to the target temperature conditions of Y. Cp is the specific heat (J / Kg·°C), m is the material delivery rate (Kg / second), and its range is 60 Kg / second to 70 Kg / second. x represents the power [W] value of the minimum energy required to reach the melting temperature. Ti is the initial temperature, which is the normal temperature during preheating, and the high-temperature heating for melting targets the final temperature of preheating.

[0167] <Formula 1>

[0168] The target temperature Y of the preheat treatment section = a(x / (Cp*m)+Ti)

[0169] For example, the minimum input heat required to reach the said target temperature is calculated as follows. Cp is set to 800 J / Kg·°C, m is set to 65 Kg / hour, and Ti is set to 25 °C. At this time, the formula can be changed as follows. The target temperature of the preheat treatment section is based on 700 degrees of the Boudouard reaction start temperature, and the target temperature of the melting treatment section is based on the minimum temperature of the reaction furnace, 1150.

[0170] <Formula 1>

[0171] The target temperature Y of the preheat treatment section = 0.813(x / (Cp×m)+25);

[0172] <Formula 2>

[0173] The target temperature Y of the melting section = 0.4(x / (Cp×m)+700);

[0174] The following Table 4 shows the reactant temperatures according to the minimum energy (kW) required for heating the preheat treatment section and the raw material of the reactants. Specifically, Table 4 below refers to the minimum value of the theoretical values considered in the heating section.

[0175]

Table 4

[0176]

[0177] As confirmed from Table 4 above, for the preheating section, as the starting temperature range for the reduction reaction, the central temperature of the reactants should be ensured with a target of approximately 700 degrees. Specifically, the power, which is the energy required to heat the raw material of the heating element, should be 12 kW or more. For the melting section, since the raw material contains a large amount of graphite, the endothermic reaction caused by the Boudouard reaction from carbon dioxide to carbon monoxide needs to be considered. Therefore, at least 16 kW or more of power is required to reach the target temperature. However, this is the minimum theoretical value required to reach the target temperature, and the amount of power that needs to be applied in the actual reaction furnace should be greater than this value.

[0178] The preferred embodiments have been described in detail above, but the scope of the rights of the present invention is not limited to the above embodiments. Various modifications and improvements made by those skilled in the art using the basic concepts defined in the claims also fall within the scope of the rights of the present invention.

Claims

1. A high-temperature reduction device for waste battery reuse, comprising: A charging section for adding raw material substances; A heating section for heating the raw material substances added from the charging section; A cooling section for cooling the product after heat treatment; And A discharging section for discharging the cooled reactants from the cooling section, The heating section includes: A preheating section for preheating the raw material substances added from the charging section; A high-temperature heat treatment section for heating at a temperature higher than that of the preheating section, The high-temperature heat treatment section includes a heat treatment section, and the heat treatment section is used for heat-treating the raw material substances in a temperature range of 1150°C to 1400°C.

2. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The high-temperature heat treatment section includes two or more heat treatment sections in the vertical or horizontal direction.

3. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The high-temperature heat treatment section includes: An endothermic section for heating at a temperature higher than that of the preheating section; and A melting section for heating in a temperature range higher than that of the endothermic section to form at least a part of a molten layer.

4. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The heating section during temperature rise raises the temperature of the raw material substances at a rate of 1°C / minute to 10°C / minute.

5. The high-temperature reduction device for waste battery reuse according to claim 3, wherein The melting section melts at least one of Ni, Cu, Co, and Mn to form spherical particles.

6. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The weight ratio of carbon to nickel (C / Ni) in the charged raw material substances is 20 or more.

7. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The heating section includes a heating furnace and a heating unit, When measuring the temperature at any position in the short-axis and long-axis directions of the cross-section of the heating furnace with reference to the central part, The temperature difference between the central part and the any position is 250°C or less.

8. The high-temperature reduction device for waste battery reuse according to claim 7, wherein The cross-section of the heating furnace has a length ratio of the long axis to the short axis of 2 / 1 to 4 / 1.

9. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The heating furnace has a bent part on the outside of the heating furnace.

10. The high-temperature reduction device for waste battery reuse according to claim 9, wherein The length of the bent part is 30 mm or more.

11. The high-temperature reduction device for waste battery reuse according to claim 1, wherein The heating section includes at least one heating unit, The heating unit has a coil shape, The coil has an interval distance between the coil pitches that becomes narrower as it gets farther from the central region of the coil.

12. The high-temperature reduction device for waste battery reuse according to claim 11, wherein The heating unit is arranged on at least a part of the heating section.

13. The high-temperature reduction device for waste battery reuse according to claim 1, wherein the target temperature of the preheating treatment section in the heating section satisfies the following formula 1 <Formula 1> T 111 ≥0.813(x / (Cp×m)+25) In the above formula 1, x is the input energy [W], Cp is the specific heat [J / Kg·℃], and m is the mass transfer amount [Kg / second].

14. The high-temperature reduction device for waste battery reuse according to claim 13, wherein x in the above formula 1 is 12000 W or more.

15. The high-temperature reduction device for waste battery reuse according to claim 3, wherein the target temperature of the melting section in the heating section satisfies the following formula 2 <Formula 2> T 113 ≥0.4(x / (Cp×m)+700) In the above formula 2, x is the input energy [W], Cp is the specific heat [J / Kg·℃], and m is the mass transfer amount [Kg / second].

16. The high-temperature reduction device for waste battery reuse according to claim 15, wherein x in the above formula 2 is 16000 W or more.

17. The high-temperature reduction device for waste battery reuse according to claim 1, wherein the heating section is carried out in an environment with an oxygen partial pressure of 0.1 atm or less.

18. The high-temperature reduction device for waste battery reuse according to claim 1, wherein in the heating section, the preheating treatment section is heated in a temperature range of 800°C or less.

19. The high-temperature reduction device for waste battery reuse according to claim 3, wherein in the heating section, the endothermic section undergoes an endothermic reaction through the Boudouard reaction in which CO2 gas is converted into 2CO.

20. A heat treatment method for waste battery reuse, which, as a heat treatment process carried out after the waste battery crushing process, includes: a charging step of adding raw material substances; a heating step of heating the raw material substances added by charging; a cooling step of cooling the heat-treated product; and a discharging step of discharging the cooled reactants, the heating step of heating the raw material substances added by charging includes: a preheating step of preheating the raw material substances added by charging; a high-temperature heat treatment step of heating at a temperature higher than that of the preheating step, the high-temperature heat treatment step includes a heat treatment step of performing heat treatment on the raw material substances in a temperature range of 1150°C to 1400°C.

21. The heat treatment method for waste battery reuse according to claim 20, wherein the high-temperature heat treatment step includes: an endothermic step of heating at a temperature higher than that of the preheating treatment section; a melting step of heating in a temperature range higher than that of the endothermic step to form at least a part of a molten layer.

22. The heat treatment method for waste battery reuse according to claim 20, wherein in the step of heating the raw material substances added by charging, when measuring the temperature at any position in the short-axis and long-axis directions of the cross-section of the heating member with reference to the center portion, the temperature difference between the center portion and the any position is 250°C or less.

23. The heat treatment method for waste battery reuse according to claim 20, wherein, the cross section of the heating furnace has a length ratio of the major axis to the minor axis of 2 / 1 to 4 / 1.

24. The heat treatment method for waste battery reuse according to claim 20, wherein, the heating furnace has a bending portion on the outer side of the heating furnace.

25. The heat treatment method for waste battery reuse according to claim 24, wherein, the length of the bending portion is 60 mm or more.

26. The heat treatment method for waste battery reuse according to claim 20, wherein, the step of preheating the raw material substance added by charging is carried out at the target temperature of the following formula 1, <Formula 1> T 111 ≥0.813(x / (Cp×m)+25) In the above formula 1, x is the input energy [W], Cp is the specific heat [J / Kg·℃], and m is the mass transfer amount [Kg / second].

27. The heat treatment method for waste battery reuse according to claim 21, wherein, the target temperature of the melting step of heating in a temperature range higher than that of the endothermic step to form at least a part of the molten layer satisfies the following formula 2, <Formula 2> T 113 ≥0.4(x / (Cp×m)+700) In the above formula 2, x is the input energy [W], Cp is the specific heat [J / Kg·℃], and m is the mass transfer amount [Kg / second].

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