Fluidized bed reactor and method for recovering active metals from lithium secondary batteries using the same

Abstract

A method for recovering an active metal for a lithium secondary battery may include supplying a positive electrode active material mixture to a fluidized bed reactor including a reactor body. A reaction gas may be introduced from the bottom of the fluidized bed reactor to form a fluidized bed containing a pre-precursor mixture within the reactor body. The fluidized bed portion entering the top of the fluidized bed reactor may be cooled and then lowered into the reactor body, after which the lithium precursor may be recovered from the pre-precursor mixture. This reduces the terminal velocity of the pre-precursor, thereby preventing loss due to scattering even when the pre-precursor has a fine particle size.

Description

[Technical Field]

[0001] The present disclosure relates to a fluidized bed reactor and a method for recovering active metals of lithium secondary batteries using the same, and more particularly to a fluidized bed reactor capable of performing a dry reaction by fluidizing particles and a method for recovering active metals of lithium secondary batteries using the same. [Background technology]

[0002] In recent years, secondary batteries have been widely developed and applied as power sources for portable electronic communication devices such as camcorders, mobile phones, and laptop computers, as well as for vehicles such as hybrid cars and electric cars. As secondary batteries, lithium secondary batteries have been actively developed and applied because of their high operating voltage and energy density per unit weight, as well as their advantages in terms of charging speed and light weight.

[0003] The positive electrode active material of the lithium secondary battery can be a lithium metal oxide, which can further contain a transition metal such as nickel, cobalt, or manganese.

[0004] Since the positive electrode active material contains the above-mentioned expensive valuable metals, the production of the positive electrode material accounts for more than 20% of the production cost. In addition, with the recent increase in interest in environmental protection, research into methods for recycling positive electrode active materials is progressing.

[0005] Conventionally, valuable metals have been recovered by leaching waste cathode active material in a strong acid such as sulfuric acid. However, this wet process has disadvantages in terms of regeneration selectivity and regeneration time, and may cause environmental pollution. Therefore, research is being conducted into methods for recovering valuable metals using dry-based reactions involving contact with reactive gases.

[0006] However, as the size of the active material particles supplied to the dry reaction becomes smaller, the flow of the active material particles may not be substantially controlled. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present disclosure is to provide a fluidized bed reactor with improved reaction yield and reaction reliability.

[0008] Another object of the present disclosure is to provide a method for recovering active metals from a lithium secondary battery using the fluidized bed reactor. [Means for solving the problem]

[0009] In a method for recovering an active metal for a lithium secondary battery according to an embodiment of the present disclosure, a positive electrode active material mixture may be supplied to a fluidized bed reactor including a reactor body. A reaction gas may be introduced from a lower portion of the fluidized bed reactor to form a fluidized bed containing a pre-precursor mixture within the reactor body. The fluidized bed portion that has entered an upper portion of the fluidized bed reactor may be cooled and then lowered into the reactor body. A lithium precursor may be recovered from the pre-precursor mixture.

[0010] In some embodiments, the fluidized bed reactor may include an extension pipe communicating with the reactor body and an intermediate section connecting the extension pipe and the reactor body, and cooling of the fluidized bed portion may be performed within the extension pipe.

[0011] In some embodiments, cooling of the fluidized bed portion may be achieved by a cooling jacket surrounding the outer wall of the expansion tube.

[0012] In some embodiments, cooling of the fluidized bed portion may be accomplished by cooling coils or cooling fins disposed within the expansion tube.

[0013] In some embodiments, cooling the fluidized bed portion can include contacting the cooling coil with the fluidized bed portion that has risen into the expansion tube.

[0014] In some embodiments, cooling the fluidized bed portion may include injecting a coolant directly into the expansion tube.

[0015] In some embodiments, the transition section can include a sloped sidewall extending from the end of the reactor body to the extension tube.

[0016] In some embodiments, the internal temperature of the expansion tube can be maintained lower than the internal temperature of the reactor body.

[0017] In some embodiments, the internal temperature of the expansion tube may be 20 to 300°C, and the internal temperature of the reactor body may be 400 to 700°C.

[0018] In some embodiments, cooling the fluidized bed portion that enters the upper portion of the fluidized bed reactor can include slowing the velocity of movement of particles contained in the pre-precursor mixture to below terminal velocity.

[0019] A fluidized bed reactor according to an exemplary embodiment may include a reactor body, an extension pipe connected to an end of the reactor body and having a width greater than that of the reactor body, and a cooling jet port fixed to an upper surface of the extension pipe and configured to directly inject a cooling medium onto the reactants.

[0020] In some embodiments, the reactor may further include an intermediate section connecting the reactor body and the extension tube and including a sloped sidewall.

[0021] In some embodiments, the inclination angle between an imaginary vertical line extending from the inner wall of the reactor body and the inclined side wall may be 30° to 80°.

[0022] In some embodiments, the reactor may further include a lower reactor portion connected to the bottom of the reactor body, a fluid inlet portion for injecting a reaction gas into the lower reactor portion, and a fluid outlet portion connected to the extension pipe for discharging the reaction gas.

[0023] In some embodiments, the reactor may further include a dispersion plate that separates the reactor lower portion from the reactor main body. [Effects of the Invention]

[0024] The fluidized bed reactor according to the exemplary embodiment may have a cooling unit to cool the upper portion of the fluidized bed reactor, thereby minimizing the loss of the pre-precursor mixture to the outside of the fluidized bed reactor due to the high upward velocity of the fluidized bed.

[0025] In some embodiments, the upper portion of the fluidized bed reactor may include an expansion tube. In this case, the movement space of the pre-precursor mixture entering the expansion tube may be expanded, thereby reducing the ascending speed. The expansion tube may also include a cooling unit to quickly lower the temperature inside the expansion tube. In this case, the pre-precursor mixture may be dispersed and rejoin the fluidized bed reaction. This may improve the reduction efficiency in the fluidized bed and the yield of the lithium precursor. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram illustrating a fluidized bed reactor according to an exemplary embodiment and a method for recovering active metals of a lithium secondary battery using the same. [Figure 2] FIG. 2 is a schematic cross-sectional view of a fluidized bed reactor according to an exemplary embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view of a fluidized bed reactor according to an exemplary embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view of a fluidized bed reactor according to an exemplary embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view of a fluidized bed reactor according to an exemplary embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining the flow characteristics in a fluidized bed reactor. DETAILED DESCRIPTION OF THE INVENTION

[0027] Embodiments of the present disclosure provide a fluidized bed reactor including an upper cooling section, and a method for recovering active metals of a lithium secondary battery using the fluidized bed reactor.

[0028] The present disclosure will be described in detail below with reference to the accompanying drawings, but these embodiments are merely illustrative and are not intended to limit the present invention.

[0029] As used herein, the term "precursor" is used to refer collectively to a compound containing a specific metal to provide the specific metal contained in the electrode active material.

[0030] FIG. 1 is a schematic diagram illustrating a fluidized bed reactor according to an exemplary embodiment and a method for recovering active metals of a lithium secondary battery using the same.

[0031] For convenience of explanation, FIG. 1 shows both a process flow diagram and a schematic cross-sectional view of a fluidized bed reactor.

[0032] Referring to FIG. 1, a positive electrode active material mixture can be prepared from the positive electrode of a lithium secondary battery (for example, step S10).

[0033] The lithium secondary battery may include an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and the positive electrode and the negative electrode may include a positive electrode active material layer and a negative electrode active material layer coated on a positive electrode current collector and a negative electrode current collector, respectively.

[0034] For example, the positive electrode active material contained in the positive electrode active material layer may include an oxide containing lithium and a transition metal.

[0035] In some embodiments, the positive electrode active material may include a compound represented by Formula 1:

[0036] [Chemical formula 1] Li xM1 a M2 b M3 c O y

[0037] In Chemical Formula 1, M1, M2, and M3 may be a transition metal selected from Ni, Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, or B. <x≦1.1、2≦y≦2.02、0<a<1、0<b<1、0<c<1、0<a+b+c≦1であってもよい。

[0038] In some embodiments, the active cathode material may be an NCM-based lithium oxide containing nickel, cobalt, and manganese.

[0039] The positive electrode can be recovered by separating it from the lithium secondary battery. The positive electrode includes a positive electrode current collector (e.g., aluminum (Al)) and a positive electrode active material layer as described above, and the positive electrode active material layer can include a conductive material and a binder in addition to the positive electrode active material.

[0040] The conductive material may include, for example, a carbon-based material such as graphite, carbon black, graphene, carbon nanotubes, etc. The binder may include, for example, a resin material such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, etc.

[0041] According to an exemplary embodiment, the recovered positive electrode may be pulverized to produce a positive electrode active material mixture. The positive electrode active material mixture may be prepared in powder form. The positive electrode active material mixture may include a lithium-transition metal oxide powder, such as an NCM-based lithium oxide powder (e.g., Li(NCM)O), as described above.

[0042] As used herein, the term "positive electrode active material mixture" may refer to raw materials input into a fluidized bed reaction process, which will be described later, after the positive electrode current collector has been substantially removed from the positive electrode. In one embodiment, the positive electrode active material mixture may include positive electrode active material particles, such as the NCM-based lithium oxide. In one embodiment, the positive electrode active material mixture may also include a component derived from the binder or the conductive material. In one embodiment, the positive electrode active material mixture may be substantially composed of the positive electrode active material particles.

[0043] In some embodiments, the positive electrode active material mixture may have an average particle size (D50) of 5 to 100 μm, which allows the lithium-transition metal oxide to be recovered, such as Li(NCM)O, to be easily separated from the positive electrode current collector, conductive material, and binder contained in the positive electrode active material mixture.

[0044] In some embodiments, the cathode active material mixture may be heat-treated before being introduced into a fluidized bed reactor, as described below. The heat treatment may remove or reduce impurities, such as the conductive material and binder, contained in the cathode active material mixture. This allows the lithium-transition metal oxide to be introduced into the fluidized bed reactor with high purity.

[0045] The temperature of the heat treatment may be, for example, about 100° C. to 500° C., or about 350° C. to 450° C. Within this range, the impurities are substantially removed, and decomposition and damage to the lithium-transition metal oxide can be prevented.

[0046] For example, in step S20, the positive electrode active material mixture may be reacted with a reactant gas in a fluidized bed reactor 100 to form a pre-precursor mixture 80.

[0047] 1, the fluidized bed reactor 100 may include a reactor body 110, a reactor lower portion 120, and an extension pipe 130. The reactor body 110 may include a heating means such as a heater, or may be integrated with the heating means.

[0048] The reactor body 110 can have a cylindrical shape. In some embodiments, the sidewalls of the reactor body 110 can be substantially vertical. For example, the sidewalls of the reactor body 110 can be vertical from the top surface of the distributor plate 50.

[0049] According to an exemplary embodiment, a reaction gas can be introduced into the lower reactor section 120. In some embodiments, the lower reactor section 120 can be defined as the section below the distributor plate 50 of the fluidized bed reactor 100. For example, the distributor plate 50 can separate the reactor body 110 from the lower reactor section 120.

[0050] The positive electrode active material mixture may be supplied to the reactor body 110 through a supply channel 108a. The positive electrode active material mixture may be dropped through the supply channel 108a connected to the top of the reactor body 110. The positive electrode active material mixture may also be introduced through a supply channel (not shown) connected to the bottom of the reactor body 110.

[0051] As previously mentioned, the reactant gases can be supplied to the lower reactor section 120. In some embodiments, the lower reactor section 120 can include a fluid inlet 104a through which the reactant gases are injected.

[0052] The reaction gas may be introduced into the reactor lower portion 120 through the fluid inlet 104a and then supplied into the reactor body 110. According to an exemplary embodiment, the reaction gas may be ejected from the bottom of the reactor body 110 through an injection column 60 included in the dispersion plate 50.

[0053] A reactant gas is supplied from the lower part of the fluidized bed reactor 100 and contacts the positive electrode active material mixture, and the positive electrode active material mixture moves to the extension tube 130 and reacts with the reactant gas, thereby being converted into a pre-precursor mixture 80.

[0054] The reactant gas may include a reducing gas, such as hydrogen (H). The positive electrode active material mixture may be reduced by the reactant gas to produce, for example, lithium hydroxide (LiOH), a lithium oxide (e.g., LiO), and a transition metal or transition metal oxide. For example, the reductive reaction may produce Ni, Co, NiO, CoO, and MnO along with the lithium precursor.

[0055] The reduction reaction in the reactor main body 110 can be carried out at a temperature of 400° C. to 700° C. or 450° C. to 550° C. Within this reaction temperature range, the reduction reaction can be promoted without causing re-aggregation or recombination of the preliminary lithium precursor and the transition metal / transition metal oxide.

[0056] In some embodiments, a carrier gas may be supplied along with the reactant gas from the lower reactor portion 120. For example, the carrier gas may be supplied along with the reactant gas through the fluid inlet 104a.

[0057] For example, the carrier gas may include an inert gas such as nitrogen (N2), argon (Ar), etc. The carrier gas may also be injected through the injection column 60 of the dispersion plate to promote the formation of a fluidized bed in which the reduction reaction takes place. For example, the carrier gas may promote the formation of a cyclone.

[0058] The fluidized bed may be formed within the reactor body 110 and may rise to enter the upper portion of the fluidized bed reactor 100. According to an exemplary embodiment, a pre-precursor mixture 80 including a pre-lithium precursor and a pre-transition metal precursor (e.g., the transition metal or transition metal oxide) may be formed by a reduction reaction in the fluidized bed. The pre-lithium precursor may include, for example, lithium hydroxide, lithium oxide, and / or lithium carbonate.

[0059] According to an exemplary embodiment, the fluidized bed may at least partially enter the expansion tube 130. The expansion tube 130 may have a diameter or width larger than the reactor body 110. The particles of the pre-precursor mixture 80 contained in the portion of the fluidized bed that has moved into the expansion tube 130 may have their upward velocity reduced and may descend again into the reactor body 110 due to the expansion of the movement space within the expansion tube 130.

[0060] As the space in which the particles of the pre-precursor mixture 80 move within the expansion tube 130 expands, the temperature within the expansion tube 130 can decrease below the temperature within the reactor body 110. According to an exemplary embodiment, the fluidized bed reactor 130 can further include a cooling unit coupled to the expansion tube 130.

[0061] The cooling unit can more quickly reduce the temperature of the fluidized bed portion that has moved into the expansion tube 130. This allows the particles of the pre-precursor mixture 80 that have scattered into the expansion tube 130 to be quickly transferred back to the reactor body 110 and participate again in the fluidized bed reaction.

[0062] For example, if the velocity of the pre-precursor mixture 80 particles in the reactor body 110 is equal to the terminal velocity (u t If the velocity increases above the terminal velocity, turbulence may be formed, causing the particles to diffuse into the expansion tube 130.

[0063] According to an exemplary embodiment, the cooling unit can quickly reduce the moving speed of the particles of pre-precursor mixture 80 to less than the terminal velocity. For example, by making the moving speed of pre-precursor mixture 80 less than a turbulence fluidizing rate, which corresponds to the terminal velocity in a turbulence fluidizing step described below, the amount of pre-precursor mixture 80 that flows out of reactor body 110 can be effectively reduced.

[0064] This effectively reduces the amount of pre-precursor mixture 80 that flows out of the reactor body 110, thereby improving the efficiency of the reduction reaction in the fluidized bed and the yield of the lithium precursor.

[0065] In some embodiments, the cooling unit can maintain the temperature inside the extension tube 130 lower than the temperature inside the reactor body 110. For example, the cooling unit can reduce the temperature inside the extension tube 130 to 300°C or lower, or 150°C or lower. In one embodiment, the temperature inside the extension tube 130 can be reduced to between 20°C and 100°C.

[0066] In this temperature range, the temperature difference between the inside of the reactor body 110 and the extension tube 130 can effectively reduce the flow rate of the pre-precursor mixture 80 moving from the reactor body 110 to the extension tube 130.

[0067] In some embodiments, as shown in FIG. 1, the cooling unit can include cooling jets 150 mounted or secured to the interior surface of the extension tube 130 .

[0068] For example, multiple cooling jets 150 can be mounted or secured within the top surface of the extension tube 130. In one embodiment, the cooling jets 150 can also be distributed on the inner wall of the extension tube 130.

[0069] A coolant (e.g., water) can be directly sprayed onto the pre-precursor mixture 80 present in the extension tube 130 from the cooling spray nozzle 150. This allows the pre-precursor mixture 80 to come into direct contact with the coolant, thereby improving cooling efficiency. In addition, the force of the coolant sprayed from the upper surface of the extension tube 130 allows the pre-precursor mixture 80 to quickly descend into the reactor body 110.

[0070] The cooling injection port 150 can directly inject the cooling medium into the pre-precursor mixture 80 that has entered the extension tube 130. The cooling medium comes into direct contact with the pre-precursor mixture 80, and particles of the pre-precursor mixture 80 can aggregate with each other through the cooling medium.

[0071] In some embodiments, if the internal temperature of the extension tube 130 rises above a predetermined temperature, cooling can be performed by a cooling unit. For example, if the internal temperature of the extension tube 130 exceeds 300°C, the cooling jets 150 can inject the cooling medium into the pre-precursor mixture 80. In one embodiment, if the internal temperature of the extension tube 130 exceeds 150°C, the cooling jets 150 can inject the cooling medium into the pre-precursor mixture 80.

[0072] This prevents the coolant from being excessively sprayed, thereby suppressing an increase in the temperature of the pre-precursor mixture 80 that has entered the extension tube 130. This allows the pre-precursor mixture 80 to re-enter the reactor body 110.

[0073] The aggregated pre-precursor mixture 80 may increase in volume and mass, increasing its terminal velocity. Furthermore, the movement speed of the aggregated pre-precursor mixture 80 may slow down. In this case, the movement speed of the aggregated pre-precursor mixture 80 can be quickly reduced to below the terminal velocity. This reduces the amount of pre-precursor mixture 80 that flows out of the reactor body 110, effectively improving the recovery rate of the pre-precursor mixture 80.

[0074] In some embodiments, the diameter of the expansion tube 130 may be larger than the diameter of the reactor body 110. The diameter may be measured based on the central axis of the fluidized bed reactor 100 and the inner wall of the fluidized bed reactor 100. In this case, the deceleration effect of the pre-precursor mixture 80 or the reaction gas moving from the reactor body 110 to the expansion tube 130 may be maximized.

[0075] The fluidized bed reactor 100 may further include an intermediate portion 140 connecting the reactor body 110 and the extension pipe 130. The intermediate portion 140 may refer to a region extending from the end of the reactor body 110 to the extension pipe 130, with the diameter gradually increasing at a certain inclination angle (a) as the diameter of the extension pipe 130 becomes larger than the diameter of the reactor body 110. For example, the inclination angle (a) may be defined as the angle between a vertical extension line of the side surface of the reactor body 110 and the inclined surface of the intermediate portion 140.

[0076] In some embodiments, the inclination angle (a) of the intermediate portion 140 may be 30 to 80°. In one embodiment, the inclination angle (a) of the intermediate portion 140 may be 45 to 60°. When the inclination angle (a) satisfies the above range, an effective deceleration effect of the pre-precursor mixture 80 can be expected without unnecessarily increasing the area of ​​the extension pipe 130 included in the fluidized bed reactor 100.

[0077] In addition, the pre-precursor mixture 80, which is slowing down and descending, flows back into the reactor body 110 along the inclined surface of the intermediate portion 140, so that the recovery efficiency of the lithium precursor can be further improved.

[0078] For example, in step S30, the lithium precursor can be selectively recovered from the preliminary precursor mixture 80.

[0079] In some embodiments, the preliminary precursor mixture 80 can be washed with water to recover the preliminary lithium precursor. The water washing process allows the preliminary lithium precursor particles in the form of lithium hydroxide (LiOH) to be substantially dissolved in water and separated from the transition metal precursor, allowing them to be preferentially recovered. The lithium hydroxide dissolved in water can be subjected to a crystallization process or the like to obtain a lithium precursor substantially composed of lithium hydroxide.

[0080] In some embodiments, the reserve lithium precursor particles in the form of lithium oxide and lithium carbonate can be substantially removed by the water washing process.

[0081] In some embodiments, preliminary lithium precursor particles in the form of lithium oxide and lithium carbonate can be at least partially converted to lithium hydroxide by said water washing treatment.

[0082] In some embodiments, the preliminary lithium precursor can be reacted with a carbon-containing gas, such as carbon monoxide (CO) or carbon dioxide (CO), to produce lithium carbonate (e.g., LiCO) as the lithium precursor. The reaction with the carbon-containing gas can produce a crystallized lithium precursor. For example, lithium carbonate can be collected by co-injecting a carbon-containing gas during the water washing process.

[0083] For example, in step S40, the transition metal precursor can be obtained from the collected preliminary transition metal precursor.

[0084] For example, the preliminary lithium precursor can be collected via outlet 108b, followed by recovery of the preliminary transition metal precursor, which can then be treated with an acid solution to form precursors of the acid salt forms of the respective transition metals.

[0085] In some embodiments, sulfuric acid can be used as the acid solution, in which case NiSO4, MnSO4, and CoSO4 can be recovered as the transition metal precursors, respectively.

[0086] As described above, by collecting the lithium precursor through a dry process and then selectively extracting the transition metal precursor using an acid solution, the purity and selectivity of each metal precursor are improved, and the load of the wet process is reduced, thereby suppressing the increase in wastewater and by-products.

[0087] 2 to 5 are schematic cross-sectional views showing fluidized bed reactors according to exemplary embodiments. Detailed description of the structure and configuration of fluidized bed reactors that are substantially the same as or equivalent to those in FIG. 1 will be omitted.

[0088] Referring to FIG. 2, the cooling unit may include a cooling jacket 160 .

[0089] The cooling jacket 160 can at least partially surround the outer wall of the expansion tube 130. In one embodiment, the cooling jacket 160 can completely surround the outer wall of the expansion tube 130.

[0090] A coolant flows inside the cooling jacket 160, which can lower the temperature inside the extension tube 130. This reduces the moving speed of the pre-precursor mixture 80 below the terminal velocity, and effectively reduces the amount of the pre-precursor mixture 80 that flows out of the reactor body 110.

[0091] 3, the cooling unit may include a cooling coil 170. Also, referring to FIG. 4, the cooling unit may include cooling fins 180.

[0092] Cooling coils 170 or cooling fins 180 may be positioned inside the expansion tube 130 .

[0093] The cooling coil 170 or the cooling fins 180 can directly contact the pre-precursor mixture 80 to lower the temperature inside the extension tube 130. This reduces the moving speed of the pre-precursor mixture 80 below the terminal velocity, and effectively reduces the amount of the pre-precursor mixture 80 that flows out of the reactor body 110.

[0094] Referring to FIG. 5, cooling nozzles 150 may be attached to the upper surface of the extension tube 130 and the inner side of the intermediate portion 140 .

[0095] Even if the temperature inside the extension tube 130 is maintained at, for example, 300°C or less by the cooling jet nozzles 150 formed on the upper surface of the extension tube 130, the preliminary precursor mixture 80 may remain in the intermediate portion 140. In this case, a coolant can be directly sprayed onto the preliminary precursor mixture 80 remaining in the intermediate portion 130 from the cooling jet nozzles 150 formed on the inner side of the intermediate portion 140. This can further improve the recovery rate of the precursor mixture 80.

[0096] FIG. 6 is a schematic diagram for explaining the flow characteristics in the fluidized bed reactor 100. As shown in FIG.

[0097] 6, a reaction gas can be introduced into the fluidized bed reactor 100 as indicated by the arrows. Once the reaction gas is introduced, a minimum fluidized reaction bed formation step (F10) is performed, and as the flow rate of the reaction gas increases, an intermediate smooth fluidization step (F20) and then a bubbling fluidized reaction bed step (F30) can be performed.

[0098] In the bubble-forming fluidized reaction bed step (F30), the reaction particles (for example, the positive electrode active material mixture) can be retained in the fluidized reaction bed and prevented from scattering outside the fluidized reaction bed.

[0099] According to an exemplary embodiment, the flow rate of the reactant gas may be equal to or greater than the bubble-forming fluidization velocity, thereby sufficiently dispersing the small particle size of the positive electrode active material mixture and facilitating the formation of a fluidized reaction layer with the reactant gas.

[0100] If the flow velocity of the reaction gas further increases, the reaction may proceed to a vortex fluidization step (F40). In this case, fine particles that behave individually among the reaction particles may be scattered outside the fluidized reaction bed. For example, if the flow velocity of the reaction gas increases above the terminal velocity of the reaction particles, the reaction gas and the reaction particles may be more vigorously mixed and rise to the top of the fluidized bed reactor, making it substantially difficult to control the reaction.

[0101] According to an exemplary embodiment, the reactant particles that have risen to the top of the reactor may be cooled at the top of the fluidized bed reactor. The cooled reactant particles have a reduced flow rate, which reduces the rising speed of the reactant particles to below terminal velocity. This prevents the reactant particles from descending and being lost to the outside of the fluidized bed reactor along with the reactant gas. Furthermore, the reactant particles may repeatedly ascend and descend, allowing the reactant particles to undergo sufficient reaction, thereby improving the recovery yield of the lithium precursor.

[0102] Hereinafter, the embodiments of the present disclosure will be further described with reference to specific experimental examples. These embodiments are merely illustrative of the present disclosure and do not limit the scope of the appended claims. It is obvious to those skilled in the art that various changes and modifications to the embodiments can be made within the scope and technical idea of ​​the present disclosure, and it is natural that such changes and modifications also fall within the scope of the appended claims.

[0103] Example 1 (1) Preparation of waste positive electrode active material mixture 100 kg of the cathode material separated from the waste lithium secondary battery was heat-treated at 450°C for 1 hour. The heat-treated cathode material was cut into small units and pulverized by milling to obtain samples of Li-Ni-Co-Mn oxide cathode active material.

[0104] (2) Operation of the fluidized bed reactor 10 kg of the positive electrode active material sample was loaded into a fluidized bed reactor consisting of a reactor body and an expansion tube, and the fluidized bed reactor was operated by injecting nitrogen gas from the bottom of the reactor at a flow rate of 100 L / min.

[0105] The internal temperature of the reactor body was maintained at 450° C., and a cooling unit was attached to the expansion tube to maintain the internal temperature of the expansion tube at 80° C. The cooling unit was equipped with a cooling nozzle using water as a cooling solvent on the upper surface of the expansion tube.

[0106] The fluidized bed reactor used had an expansion pipe diameter ratio of 2 to the reactor body diameter.

[0107] Example 2 The fluidized bed reactor was operated in the same manner as in Example 1, except that the cooling unit attached to the expansion pipe was a cooling jacket attached to the outer wall of the expansion pipe.

[0108] Example 3 The fluidized bed reactor was operated in the same manner as in Example 1, except that the cooling unit attached to the expansion tube was a cooling coil attached inside the expansion tube.

[0109] Example 4 The fluidized bed reactor was operated in the same manner as in Example 1, except that the cooling unit attached to the expansion pipe was a cooling fin attached to the outer wall of the expansion pipe.

[0110] Example 5 The fluidized bed reactor was operated in the same manner as in Example 1, except that the internal temperature of the expansion tube was maintained at 120°C.

[0111] Example 6 The fluidized bed reactor was operated in the same manner as in Example 1, except that the internal temperature of the expansion tube was maintained at 160°C.

[0112] Comparative Example 1 The reaction was carried out in the same manner as in Example 1, except that the expansion tube was not equipped with a cooling unit.

[0113] Experimental example The amount of the pre-precursor mixture that flowed out of the reactor was measured, and the amount flowed out per hour was calculated.

[0114] [Table 1]

[0115] Referring to Table 1, when a cooling unit was attached to the extension tube, the amount of pre-precursor mixture that was lost by leaking out of the reactor was reduced. According to the examples, when a cooling unit was attached to the extension tube, the amount of pre-precursor mixture that leaked out was reduced by 70% or more compared to when a cooling unit was not attached.

[0116] In Example 6, the internal temperature of the expansion tube was maintained at 150° C. or higher, which increased the amount of pre-precursor mixture flowing out of the reactor.

[0117] In Comparative Example 1, no cooling unit was attached to the extension pipe, which resulted in an increase in the amount of pre-precursor mixture flowing out of the reactor compared to the Examples.

[0118] The foregoing is merely illustrative of the application of the principles of the present disclosure, and other arrangements may still be included without departing from the scope of the present disclosure.

Claims

1. supplying the positive electrode active material mixture to a fluidized bed reactor including a reactor body; introducing a reaction gas into the lower part of the fluidized bed reactor to form a fluidized bed containing the pre-precursor mixture in the reactor body; cooling the fluidized bed portion that has entered the upper part of the fluidized bed reactor and causing it to descend into the reactor body; and recovering a lithium precursor from the preliminary precursor mixture.

2. The fluidized bed reactor includes an extension pipe communicating with the reactor main body, and an intermediate part connecting the extension pipe and the reactor main body, The method for recovering active metals from a lithium secondary battery according to claim 1 , wherein the step of cooling the fluidized bed portion is performed within the expansion tube.

3. The method for recovering active metals from a lithium secondary battery according to claim 2 , wherein the step of cooling the fluidized bed portion is performed by a cooling jacket surrounding an outer wall of the expansion tube.

4. The method for recovering active metals from a lithium secondary battery according to claim 2 , wherein the step of cooling the fluidized bed portion is performed by a cooling coil or a cooling fin disposed inside the expansion tube.

5. 5. The method for recovering active metals from a lithium secondary battery according to claim 4, wherein the step of cooling the fluidized bed portion includes contacting the cooling coil with the fluidized bed portion that has risen into the expansion tube.

6. The method for recovering active metals from a lithium secondary battery according to claim 2 , wherein the step of cooling the fluidized bed portion comprises directly injecting a cooling medium into the inside of the expansion tube.

7. The method for recovering active metals from a lithium secondary battery according to claim 2 , wherein the intermediate portion includes a sloped sidewall extending from the end of the reactor body to the extension tube.

8. The method for recovering active metals from a lithium secondary battery according to claim 1 , wherein the internal temperature of the expansion tube is maintained lower than the internal temperature of the reactor body.

9. 9. The method for recovering active metals from a lithium secondary battery according to claim 8, wherein the internal temperature of the expansion tube is 20 to 300°C, and the internal temperature of the reactor body is 400 to 700°C.

10. 2. The method for recovering active metals of a lithium secondary battery according to claim 1, wherein the step of cooling the fluidized bed portion that has entered the upper part of the fluidized bed reactor comprises slowing down a moving velocity of particles contained in the preliminary precursor mixture to a terminal velocity or less.

11. A reactor body; an expansion tube connected to an end of the reactor body and having a width greater than that of the reactor body; a cooling jet nozzle fixed to the upper surface of the expansion tube for directly injecting a cooling medium onto the reactants.

12. 12. The fluidized bed reactor according to claim 11, further comprising an intermediate section connecting the reactor body and the extension pipe and including an inclined side wall.

13. 13. The fluidized bed reactor according to claim 12, wherein an inclination angle between an imaginary vertical line extending from the inner wall of the reactor body and the inclined side wall is 30° to 80°.

14. 12. The fluidized bed reactor of claim 11, further comprising: a reactor lower portion connected to the bottom of the reactor body; a fluid inlet portion for injecting a reaction gas into the reactor lower portion; and a fluid outlet portion connected to the extension pipe for discharging the reaction gas.

15. The fluidized bed reactor according to claim 14, further comprising a dispersion plate separating the reactor lower portion from the reactor main body.

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