Fluidized bed reactor and method for recovering active metal of lithium secondary battery using same

Abstract

A method of recovering an active metal of a lithium secondary battery may supply a positive electrode active material mixture to a fluidized bed reactor including a reactor body. A reaction gas may be introduced from a lower portion of a fluidized bed reactor to form a fluidized bed containing a preliminary precursor mixture in the reactor body. The fluidized bed portion entering the upper portion of the fluidized bed reactor may be cooled and lowered to the reactor body, and then the lithium precursor is recovered from the preliminary precursor mixture. Therefore, the termination speed of the preliminary precursor is reduced, and thus loss due to scattering can be prevented even if the particle size of the preliminary precursor is fine.

Description

Technical Field

[0001] The present invention relates to a fluidized bed reactor and a method for recovering active metals of lithium secondary batteries using the fluidized bed reactor. More specifically, the present invention relates to a fluidized bed reactor capable of performing dry reaction by particle flow and a method for recovering active metals of lithium secondary batteries using the fluidized bed reactor. Background Art

[0002] In recent years, secondary batteries are being widely used and developed as power sources for portable electronic communication devices such as camcorders, mobile phones, and laptop computers, and vehicles such as hybrid cars and electric cars. Lithium secondary batteries, which are secondary batteries, have high operating voltage and energy density per unit weight and are advantageous in terms of charging speed and lightness, and are therefore being actively developed and used.

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

[0004] Since the above-mentioned high-cost valuable metals are used in the positive electrode active material, more than 20% of the manufacturing cost is required to manufacture the positive electrode material. In addition, as environmental protection issues have become increasingly prominent in recent years, research is being conducted on recycling methods for positive electrode active materials.

[0005] In the past, a method of leaching spent positive electrode active materials with strong acids such as sulfuric acid to sequentially recover valuable metals was used, but the above-mentioned wet process is disadvantageous in terms of regeneration selectivity, regeneration time, etc., and may cause environmental pollution. Therefore, a method of recovering valuable metals by dry reaction through contact with a reaction gas is being studied.

[0006] However, as the size of active material particles supplied for dry reaction becomes finer, it may be substantially difficult to control the flow of the active material particles. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] A technical problem of the present invention is to provide a fluidized bed reactor with improved reaction yield and reaction reliability.

[0009] A technical problem of the present invention is to provide a method for recovering active metals of lithium secondary batteries using the fluidized bed reactor.

[0010] (II) Technical solution

[0011] In the method for recovering active metals of a lithium secondary battery according to an embodiment of the present invention, a positive electrode active material mixture can be supplied to a fluidized bed reactor including a reactor body. A reaction gas can be introduced from the lower portion of the fluidized bed reactor to form a fluidized bed containing a preliminary precursor mixture in the reactor body. The fluidized bed portion entering the upper portion of the fluidized bed reactor can be cooled and descended into the reactor body. A lithium precursor can be recovered from the preliminary precursor mixture.

[0012] In some embodiments, the fluidized bed reactor may include an extension pipe communicating with the reactor body and an intermediate portion connecting the extension pipe and the reactor body, and cooling of the fluidized bed portion may be performed in the extension pipe.

[0013] In some embodiments, cooling of the fluidized bed portion may be performed by a cooling jacket wrapped around the outer wall of the expansion tube.

[0014] In some embodiments, cooling of the fluidized bed portion may be performed by cooling coils or fins disposed inside the expansion tube.

[0015] In some embodiments, cooling of the fluidized bed portion may include contacting the cooling coil with the portion of the fluidized bed that rises into the expansion tube.

[0016] In some embodiments, cooling of the fluidized bed portion may include spraying a coolant directly into the interior of the expansion tube.

[0017] In some embodiments, the intermediate portion may include a sloped sidewall extending from an end of the reactor body to the expansion tube.

[0018] In some embodiments, the internal temperature of the expansion tube may be maintained lower than the internal temperature of the reactor body.

[0019] In some embodiments, the internal temperature of the expansion tube may be 20-300°C, and the internal temperature of the reactor body may be 400-700°C.

[0020] In some embodiments, the step of cooling the fluidized bed portion entering the upper portion of the fluidized bed reactor may include decelerating the moving speed of particles contained in the preliminary precursor mixture to below a terminal velocity.

[0021] A fluidized bed reactor according to an exemplary embodiment may include: a reactor body; an extension pipe, which is connected to an end of the reactor body and has a width greater than a width of the reactor body; and a cooling jet, which is fixed on the extension pipe and directly sprays a coolant to the reactants.

[0022] In some embodiments, the fluidized bed reactor may further include an intermediate portion connecting the reactor body and the expansion pipe and including an inclined sidewall.

[0023] In some embodiments, the inclination angle between an imaginary vertical line extending from the inner wall of the reactor body and the inclined sidewall may be 30°. o Up to 80 o .

[0024] In some embodiments, the fluidized bed reactor may further include: a reactor lower portion connected to the bottom of the reactor body, a fluid inlet portion for injecting reaction gas into the reactor lower portion, and a fluid outlet portion connected to the expansion pipe and discharging the reaction gas.

[0025] In some embodiments, the fluidized bed reactor may further include a dispersion plate separating the reactor lower portion and the reactor body.

[0026] (III) Beneficial effects

[0027] The fluidized bed reactor according to the exemplary embodiment may use a cooling unit to cool the upper portion of the fluidized bed reactor. The upper portion of the fluidized bed reactor is cooled, thereby minimizing the loss of the preliminary precursor mixture to the outside of the fluidized bed reactor due to the high rising speed of the fluidized bed.

[0028] In some embodiments, the fluidized bed reactor top may include an extension tube. In this case, the moving space of the preliminary precursor mixture entering the extension tube is expanded, so the rising speed can be reduced. In addition, the extension tube includes a cooling unit, so that the temperature inside the extension tube can be quickly reduced. In this case, the preliminary precursor mixture can be scattered and re-participated in the fluidized bed reaction. Therefore, the reduction efficiency and lithium precursor yield in the fluidized bed can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram for explaining a fluidized bed reactor and a method of recovering active metals of a lithium secondary battery using the fluidized bed reactor according to an exemplary embodiment.

[0030] Figures 2 to 5 is a schematic cross-sectional view showing a fluidized bed reactor according to an exemplary embodiment.

[0031] Figure 6 It is a schematic diagram used to explain the flow characteristics in a fluidized bed reactor. DETAILED DESCRIPTION

[0032] Embodiments of the present invention provide a fluidized bed reactor including an upper cooling portion and a method of recovering active metals of a lithium secondary battery using the fluidized bed reactor.

[0033] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, but this is merely exemplary, and the present invention is not limited to the specific embodiments described exemplarily.

[0034] The term "precursor" used in this specification refers to a compound containing a specific metal in order to provide the specific metal contained in the electrode active material.

[0035] Figure 1 is a schematic diagram for explaining a fluidized bed reactor and a method of recovering active metals of a lithium secondary battery using the fluidized bed reactor according to an exemplary embodiment.

[0036] For ease of explanation, Figure 1 A process flow diagram and a schematic cross section of a fluidized bed reactor are shown together.

[0037] Reference Figure 1 , a positive electrode active material mixture can be prepared from a positive electrode of a lithium secondary battery (eg, S10 process).

[0038] The lithium secondary battery may include an electrode assembly including a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode. 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 collector and a negative electrode collector, respectively.

[0039] For example, the positive electrode active material included in the positive electrode active material layer may include an oxide containing lithium and a transition metal.

[0040] In some embodiments, the positive active material may include a compound represented by the following Chemical Formula 1.

[0041] [Chemical formula 1]

[0042] Li x M1 a M2 b M3 c O y

[0043] In Chemical Formula 1, M1, M2, and M3 may be transition metals selected from Ni, Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, or B. In Chemical Formula 1, 0 <x≤1.1,2≤y≤2.02,0<a<1,0<b<1,0<c<1,0<a+b+c≤1。

[0044] In some embodiments, the positive active material may be an NCM-based lithium oxide including nickel, cobalt, and manganese.

[0045] The positive electrode may be separated from the lithium secondary battery to recover the positive electrode. As described above, the positive electrode includes a positive electrode current collector (eg, aluminum (Al)) and a positive electrode active material layer, and the positive electrode active material layer may include the above-mentioned positive electrode active material as well as a conductive material and a binder.

[0046] The conductive material may include carbon-based materials such as graphite, carbon black, graphene, carbon nanotubes, etc. The adhesive may include resin materials such as vinylidene fluoride-co-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, etc.

[0047] According to an exemplary embodiment, the recovered positive electrode can be crushed to generate a positive electrode active material mixture. Therefore, the positive electrode active material mixture can be made into a powder form. As described above, the positive electrode active material mixture includes a powder of a lithium transition metal oxide, for example, it can include an NCM-based lithium oxide powder (e.g., Li(NCM)O2).

[0048] The term "positive electrode active material mixture" used in this specification may refer to a raw material added to the fluidized bed reaction process described later after substantially removing the positive electrode current collector 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 spent positive electrode active material mixture may also include a portion of components 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.

[0049] In some embodiments, the average particle size (D50) of the positive active material mixture may be 5-100 μm. Within the above range, the lithium transition metal oxide such as Li(NCM)O2 as a recycling object can be easily separated from the positive current collector, conductive material and binder contained in the positive active material mixture.

[0050] In some embodiments, the positive electrode active material mixture may be heat treated before being added to the fluidized bed reactor described later. Impurities such as the conductive material and the binder contained in the positive electrode active material mixture may be removed or reduced by the heat treatment. Therefore, the lithium-transition metal oxide may be added to the fluidized bed reactor with high purity.

[0051] The heat treatment temperature may be, for example, about 100° C. to 500° C., or may be about 350° C. to 450° C. Within the above range, the impurities may be substantially removed, and decomposition and damage of the lithium transition metal oxide may be prevented.

[0052] For example, in the S20 process, the cathode active material mixture may be reacted with a reaction gas in the fluidized bed reactor 100 to form a preliminary precursor mixture 80 .

[0053] like Figure 1 As shown, the fluidized bed reactor 100 may include a reactor body 110, a reactor lower portion 120, and an expansion pipe 130. The reactor body 110 may include a heating device such as a heater, or may be integrally formed with the heating device.

[0054] The reactor body 110 may have a cylindrical shape. In some embodiments, the sidewall of the reactor body 110 may be substantially vertical. For example, the sidewall of the reactor body 110 may be perpendicular to the upper surface of the dispersion plate 50.

[0055] According to an exemplary embodiment, the reaction gas may be introduced from the reactor lower portion 120. In some embodiments, the reactor lower portion 120 may be defined as a lower portion of the dispersion plate 50 of the fluidized bed reactor 100. For example, the reactor body 110 and the reactor lower portion 120 may be separated by the dispersion plate 50.

[0056] The positive electrode active material mixture may be supplied to the reactor body 110 through the supply channel 108a. The positive electrode active material mixture may be added dropwise through the supply channel 108a connected to the upper portion of the reactor body 110. The positive electrode active material mixture may also be added through a supply channel (not shown) connected to the bottom of the reactor body 110.

[0057] As described above, the reaction gas may be supplied to the reactor lower portion 120. In some embodiments, the reactor lower portion 120 may include a fluid introduction portion 104a into which the reaction gas is injected.

[0058] The reaction gas may be introduced into the reactor lower portion 120 through the fluid introduction part 104a to be supplied to the inside of the reactor body 110. According to an exemplary embodiment, the reaction gas may be sprayed from the bottom of the reactor body 110 through the spray column 60 included in the dispersion plate 50.

[0059] The reaction gas is supplied from the lower portion of the fluidized bed reactor 100 and contacts the cathode active material mixture, so the cathode active material mixture may move to the extension pipe 130 and react with the reaction gas to be transformed into the preliminary precursor mixture 80 .

[0060] The reaction gas may include a reducing gas, for example, hydrogen (H2). The positive electrode active material mixture may be reduced by the reaction gas to generate, for example, a preliminary lithium precursor including lithium hydroxide (LiOH), a lithium oxide (for example, LiO2), and a transition metal or a transition metal oxide. For example, Ni, Co, NiO, CoO, and MnO may be generated while the preliminary lithium precursor is generated by a reducing reaction.

[0061] The reduction reaction in the reactor body 110 may be performed at 400° C. to 700° C., or may be performed at 450° C. to 550° C. Within the above reaction temperature range, re-aggregation and recombination of the preliminary lithium precursor and the transition metal / transition metal oxide are not caused, and the reduction reaction may be promoted.

[0062] In some embodiments, a carrier gas may be supplied together with the reaction gas from the reactor lower portion 120. For example, the carrier gas may be supplied together with the reaction gas through the fluid introduction portion 104a.

[0063] For example, the carrier gas may include an inert gas such as nitrogen (N2), argon (Ar), etc. The carrier gas may also be supplied by spraying through the spray column 60 of the dispersion plate to promote the formation of a fluidized bed for the reduction reaction. For example, the formation of a cyclone through the carrier gas may be promoted.

[0064] The fluidized bed is formed in the reactor body 110 and can be raised while entering the upper part of the fluidized bed reactor 100. According to an exemplary embodiment, a preliminary precursor mixture 80 including a preliminary lithium precursor and a preliminary transition metal precursor (e.g., the transition metal or transition metal oxide) can be formed in the fluidized bed through a reduction reaction. The preliminary lithium precursor can include, for example, lithium hydroxide, lithium oxide and / or lithium carbonate (lithium carbonate).

[0065] According to an exemplary embodiment, the fluidized bed may at least partially enter the extension pipe 130. The extension pipe 130 may have a larger diameter or width than the reactor body 110. The particles of the preliminary precursor mixture 80 contained in the fluidized bed portion that moves into the extension pipe 130 may descend back into the reactor body 110 while the ascending speed decreases as the moving space expands in the extension pipe 130.

[0066] As the movement space of the preliminary precursor mixture 80 particles in the extension pipe 130 is expanded, the temperature in the extension pipe 130 may be lower than the temperature in the reactor body 110. According to an exemplary embodiment, the fluidized bed reactor 130 may further include a cooling unit coupled to the extension pipe 130.

[0067] The temperature of the fluidized bed portion moved into the extension pipe 130 can be more quickly lowered by the cooling unit. Therefore, the particles of the preliminary precursor mixture 80 scattered to the extension pipe 130 can be quickly transferred back to the reactor body 110 and re-participate in the fluidized bed reaction.

[0068] For example, the velocity of the particles of the preliminary precursor mixture 80 in the reactor body 110 increases to a terminal velocity (u t When the velocity is above terminal velocity, turbulence is formed and the particles can diffuse into the expansion tube 130.

[0069] According to an exemplary embodiment, the moving speed of the particles of the preliminary precursor mixture 80 can be quickly reduced to less than the terminal speed by the cooling unit. For example, the moving speed of the preliminary precursor mixture 80 can effectively reduce the amount of the preliminary precursor mixture 80 flowing out of the reactor body 110 by having a value of a turbulence fluidizing speed (turbulence fluidizing rate) less than the terminal speed corresponding to the turbulence fluidizing step described below.

[0070] Therefore, the amount of the preliminary precursor mixture 80 flowing out to the outside of the reactor body 110 can be effectively reduced, and the reduction reaction efficiency and the lithium precursor yield in the fluidized bed can be improved.

[0071] In some embodiments, the temperature inside the extension pipe 130 may be maintained lower than the temperature inside the reactor body 110 by the cooling unit. For example, the temperature inside the extension pipe 130 may be reduced to below 300° C. or below 150° C. by the cooling unit. In one embodiment, the temperature inside the extension pipe 130 may be reduced to 20° C. to 100° C.

[0072] In the above temperature range, due to the temperature difference between the inside of the reactor body 110 and the extension pipe 130 , the flow rate of the preliminary precursor mixture 80 moving from the reactor body 110 to the extension pipe 130 can be effectively reduced.

[0073] In some embodiments, such as Figure 1 As shown, the cooling unit may include a cooling injection port 150 attached or fixed to the inner surface of the extension pipe 130 .

[0074] For example, a plurality of cooling jets 150 may be attached or fixed on the inside of the extension tube 130. In one embodiment, the cooling jets 150 may also be distributed on the inner side wall of the extension tube 130.

[0075] The coolant (e.g., water) can be directly sprayed from the cooling spray port 150 to the preliminary precursor mixture 80 present in the extension pipe 130. Therefore, the preliminary precursor mixture 80 can be directly in contact with the coolant while improving the cooling efficiency. In addition, due to the force of the coolant sprayed from the upper side inside the extension pipe 130, the preliminary precursor mixture 80 can quickly drop into the reactor body 110.

[0076] The cooling injection port 150 may inject the coolant directly into the preliminary precursor mixture 80 entering the extension pipe 130. The coolant directly contacts the preliminary precursor mixture 80, so that the preliminary precursor mixture 80 may aggregate particles with the coolant as a medium.

[0077] In some embodiments, when the internal temperature of the extension tube 130 rises above a predetermined temperature, cooling may be performed by a cooling unit. For example, when the internal temperature of the extension tube 130 exceeds 300° C., the cooling jet 150 may spray the coolant into the preliminary precursor mixture 80. In one embodiment, when the internal temperature of the extension tube 130 exceeds 150° C., the cooling jet 150 may spray the coolant into the preliminary precursor mixture 80.

[0078] Therefore, the temperature increase rate of the preliminary precursor mixture 80 entering the extension pipe 130 can be suppressed without excessive injection of the coolant. Therefore, the preliminary precursor mixture 80 can re-enter the reactor body 110.

[0079] The aggregated preliminary precursor mixture 80 can increase the terminal velocity due to the increase in volume and mass. In addition, the moving speed of the aggregated preliminary precursor mixture 80 can be decelerated. In this case, the moving speed of the aggregated preliminary precursor mixture 80 can be quickly reduced to below the terminal velocity. Therefore, by reducing the amount of the preliminary precursor mixture 80 flowing out to the outside of the reactor body 110, the recovery rate of the preliminary precursor mixture 80 can be effectively improved.

[0080] In some embodiments, the diameter of the extension 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 preliminary precursor mixture 80 or the reaction gas moving from the reactor body 110 to the extension tube 130 may be maximized.

[0081] The fluidized bed reactor 100 may further include an intermediary portion 140 connecting the reactor body 110 and the extension tube 130. The intermediary portion 140 may refer to a region where the diameter of the extension tube 130 gradually increases from the end of the reactor body 110 at a predetermined inclination angle a and extends to the extension tube 130 as the diameter of the extension tube 130 is larger than the diameter of the reactor body 110. For example, the inclination angle a may be defined as an angle formed by a vertical extension line to the side surface of the reactor body 110 and an inclined surface of the intermediary portion 140.

[0082] In some embodiments, the inclination angle a of the intermediary portion 140 may be 30-80°. In one embodiment, the inclination angle a of the intermediary portion 140 may be 45-60°. When the inclination angle a satisfies the above range, an effective deceleration effect of the preliminary precursor mixture 80 can be expected within a range in which the area of ​​the extension pipe 130 included in the fluidized bed reactor 100 is not unnecessarily increased.

[0083] In addition, the preliminary precursor mixture 80 that is decelerated and descends is reintroduced into the reactor body 110 along the inclined surface of the intermediary portion 140 , thereby further improving the recovery efficiency of the lithium precursor.

[0084] For example, in the S30 process, the lithium precursor may be selectively recovered from the preliminary precursor mixture 80 .

[0085] In some embodiments, the preliminary precursor mixture 80 may be washed with water to recover the preliminary lithium precursor. Through the water washing process, the preliminary lithium precursor particles in the form of lithium hydroxide (LiOH) are substantially dissolved in water and separated from the transition metal precursor, and thus can be preferentially recovered. A lithium precursor substantially composed of lithium hydroxide can be obtained through a crystallization process of lithium hydroxide dissolved in water, etc.

[0086] In some embodiments, preliminary lithium precursor particles in the form of lithium oxide and lithium carbonate may be substantially removed by the water washing treatment.

[0087] In some embodiments, at least a portion of the preliminary lithium precursor particles in the form of lithium oxide and lithium carbonate may be converted into lithium hydroxide through the water washing treatment.

[0088] In some embodiments, lithium carbonate (e.g., Li2CO3) as a lithium precursor may be obtained by reacting a preliminary lithium precursor with a carbon-containing gas such as carbon monoxide (CO), carbon dioxide (CO2), etc. A crystallized lithium precursor may be obtained by reacting with the carbon-containing gas. For example, a carbon-containing gas may be injected together during the water washing process to collect lithium carbonate.

[0089] For example, in the S40 process, a transition metal precursor may be obtained from the collected preliminary transition metal precursor.

[0090] For example, after the preliminary lithium precursor is collected through the discharge port 108b, the preliminary transition metal precursor may be recovered. Thereafter, the preliminary transition metal precursor may be treated with an acid solution to form a precursor in the form of an acid salt of each transition metal.

[0091] In some embodiments, the acid solution may use sulfuric acid. In this case, NiSO4, MnSO4 and CoSO4 may be recovered as the transition metal precursors, respectively.

[0092] As described above, the lithium precursor is collected through a dry process and then the transition metal precursor is selectively extracted with an acid solution, so the purity and selectivity of each metal precursor are improved, and the load of the wet process is reduced, thereby reducing the increase of wastewater and by-products.

[0093] Figures 2 to 5 is a schematic cross-sectional view showing a fluidized bed reactor according to an exemplary embodiment. Figure 1 Detailed description of the structure and configuration of fluidized bed reactors having substantially the same or similar contents as those described herein is omitted.

[0094] Reference Figure 2 , the cooling unit may include a cooling jacket 160 .

[0095] The cooling jacket 160 may wrap at least a portion of the outer sidewall of the extension tube 130. In one embodiment, the cooling jacket 160 may wrap the entirety of the outer sidewall of the extension tube 130.

[0096] The coolant may flow inside the cooling jacket 160 to reduce the temperature inside the extension pipe 130. Therefore, the moving speed of the preliminary precursor mixture 80 is reduced to be less than the terminal speed, so that the amount of the preliminary precursor mixture 80 flowing out of the reactor body 110 can be effectively reduced.

[0097] Reference Figure 3 , the cooling unit may include a cooling coil 170. In addition, referring to Figure 4 , the cooling unit may include a heat sink 180 .

[0098] A cooling coil 170 or a heat sink 180 may be disposed inside the extension tube 130 .

[0099] The cooling coil 170 or the heat sink 180 may directly contact the preliminary precursor mixture 80 to reduce the temperature inside the extension pipe 130. Therefore, the moving speed of the preliminary precursor mixture 80 is reduced to less than the terminal speed, so that the amount of the preliminary precursor mixture 80 flowing out of the reactor body 110 can be effectively reduced.

[0100] Reference Figure 5 A cooling injection port 150 may be attached to the extension tube 130 and the inner side of the intermediary portion 140 .

[0101] When the temperature inside the extension tube 130 is maintained at, for example, 300° C. or less through the cooling injection port 150 formed on the extension tube 130, the preliminary precursor mixture 80 may still remain inside the intermediary portion 140. In this case, the coolant is directly injected from the cooling injection port 150 formed on the inner side of the intermediary portion 140 into the preliminary precursor mixture 80 remaining inside the intermediary portion 130. Therefore, the recovery rate of the preliminary precursor mixture 80 can be further improved.

[0102] Figure 6 It is a schematic diagram for explaining the flow characteristics in the fluidized bed reactor 100.

[0103] Reference Figure 6 As shown by the arrows, a reaction gas may be introduced into the fluidized bed reactor 100. With the introduction of the reaction gas, the flow rate of the reaction gas increases after the minimum fluidized reaction layer forming step F10, and after the intermediate smooth fluidization step F20, a bubble forming fluidized reaction layer step F30 may be performed.

[0104] In the bubble forming fluidized reaction layer step F30 , the reaction particles (eg, the positive electrode active material mixture) are retained in the fluidized reaction layer and are not scattered outside the fluidized reaction layer.

[0105] According to an exemplary embodiment, the flow rate of the reaction gas may be equal to or higher than the bubble formation fluidization velocity. Therefore, the formation of a fluidized reaction layer with the reaction gas can be promoted by sufficient dispersion of the positive electrode active material mixture having a small particle size.

[0106] When the flow rate of the reaction gas is further increased, a turbulent fluidization step F40 may be performed. In this case, fine particles in the reaction particles that move individually may be scattered outside the fluidized reaction layer. For example, when the flow rate of the reaction gas is increased to above the terminal velocity of the reaction particles, the reaction gas and the reaction particles are more violently mixed and rise to the upper part of the fluidized bed reactor, and it may be substantially difficult to control the reaction.

[0107] According to an exemplary embodiment, the reaction particles rising to the upper part of the reactor can be cooled at the upper part of the fluidized bed reactor. The flow rate of the cooled reaction particles is reduced, and the rising speed of the reaction particles can be reduced to below the terminal speed. Therefore, the reaction particles can be made to fall to suppress the loss of the reaction particles together with the reaction gas to the outside of the fluidized bed reactor. In addition, since the reaction particles can repeatedly rise and fall, the reaction particles can improve the recovery yield of the lithium precursor by performing sufficient reaction.

[0108] The embodiments of the present invention are further described below with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are only used to illustrate the present invention and are not used to limit the scope of rights. Various modifications and variations can be made to the embodiments within the scope of the present invention and the technical concept, which is obvious to those skilled in the art, and these modifications and variations also fall within the scope of the claims.

[0109] Example 1

[0110] (1) Preparation of waste positive electrode active material mixture

[0111] 100 kg of the positive electrode material separated from the waste lithium secondary battery was heat-treated at 450° C. for 1 hour. The heat-treated positive electrode material was cut into small units and pulverized by milling to obtain a Li—Ni—Co—Mn oxide positive electrode active material sample.

[0112] (2) Operation of fluidized bed reactor

[0113] 10 kg of the positive electrode active material sample was loaded into a fluidized bed reactor consisting of a reactor body and an extension tube, and nitrogen was injected from the bottom of the reactor at a flow rate of 100 L / min to operate the fluidized bed reactor.

[0114] The temperature inside the reactor body was maintained at 450° C., and a cooling unit was provided in the extension tube to maintain the temperature inside the extension tube at 80° C. The cooling unit was provided with a cooling jet on the inside of the extension tube using water as a cooling solvent.

[0115] Furthermore, a fluidized bed reactor having a ratio of 2 between the diameter of the extension tube and the diameter of the reactor body was used.

[0116] Example 2

[0117] The fluidized bed reactor was operated in the same manner as in Example 1, except that the cooling unit provided in the extension tube was a cooling jacket provided on the outer wall of the extension tube.

[0118] Example 3

[0119] The fluidized bed reactor was operated in the same manner as in Example 1, except that the cooling unit provided in the extension tube was a cooling coil provided inside the extension tube.

[0120] Example 4

[0121] The fluidized bed reactor was operated in the same manner as in Example 1, except that the cooling unit provided in the extension tube was a heat sink provided on the outer wall of the extension tube.

[0122] Example 5

[0123] The fluidized bed reactor was operated by the same method as in Example 1, except that the temperature inside the expansion tube was maintained at 120°C.

[0124] Example 6

[0125] The fluidized bed reactor was operated by the same method as in Example 1, except that the temperature inside the expansion tube was maintained at 160°C.

[0126] Comparative Example 1

[0127] The reaction was carried out by the same method as in Example 1, except that no cooling unit was provided in the extension tube.

[0128] Experimental example

[0129] The amount of the preliminary precursor mixture flowing out to the outside of the reactor was measured and the outflow per hour was calculated.

[0130] [Table 1]

[0131]

[0132] Referring to Table 1, when a cooling unit is provided in the extension tube, the amount of the preliminary precursor mixture flowing out to the outside of the reactor and lost is reduced. According to an embodiment, when a cooling unit is provided in the extension tube, the amount of the preliminary precursor mixture flowing out to the outside is reduced by more than 70% compared to a case where no cooling unit is provided.

[0133] In Example 6, the temperature inside the extension tube was maintained at more than 150° C. Therefore, the amount of the preliminary precursor mixture flowing out to the outside of the reactor increased.

[0134] In Comparative Example 1, no cooling unit was provided in the extension pipe. Therefore, the amount of the preliminary precursor mixture flowing out to the outside of the reactor increased compared with the examples.

[0135] The contents described above are merely examples of applying the principles of the present invention, and other configurations may be further included without departing from the scope of the present invention.

Claims

1. A method for recovering active metals from a lithium secondary battery, comprising the following steps: supplying a positive electrode active material mixture into a fluidized bed reactor including a reactor body; introducing a reaction gas from a lower portion of the fluidized bed reactor to form a fluidized bed containing a preliminary precursor mixture in the reactor body; Cooling the fluidized bed portion entering the upper portion of the fluidized bed reactor and descending into the reactor body; as well as A lithium precursor is recovered from the preliminary precursor mixture.

2. The method for recovering active metals from lithium secondary batteries according to claim 1, wherein: The fluidized bed reactor comprises an extension pipe connected to the reactor body and an intermediary portion connecting the extension pipe and the reactor body. And the cooling step of the fluidized bed portion is carried out in the expansion pipe.

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

4. The method for recovering active metals from lithium secondary batteries according to claim 2, wherein: The cooling step of the fluidized bed section is performed by cooling coils or radiators arranged inside the expansion tube.

5. The method for recovering active metals from lithium secondary batteries according to claim 4, wherein: The step of cooling the fluidized bed portion includes contacting the cooling coil with the fluidized bed portion ascending to the expansion tube.

6. The method for recovering active metals from lithium secondary batteries according to claim 2, wherein: The step of cooling the fluidized bed portion includes spraying a coolant directly into the interior of the expansion tube.

7. The method for recovering active metals from lithium secondary batteries according to claim 2, wherein: The intermediate portion includes an inclined sidewall extending from an end of the reactor body to the expansion tube.

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

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

10. The method for recovering active metals from lithium secondary batteries according to claim 1, wherein: The step of cooling the fluidized bed portion entering the upper portion of the fluidized bed reactor includes decelerating the moving speed of particles contained in the preliminary precursor mixture to below a terminal speed.

11. A fluidized bed reactor comprising: Reactor body; An extension pipe, the extension pipe is connected to the end of the reactor body, and the width of the extension pipe is greater than the width of the reactor body; as well as A cooling injection port is fixed on the extension tube and directly injects a coolant to the reactants.

12. The fluidized bed reactor according to claim 11, wherein: The fluidized bed reactor further includes an intermediate portion connecting the reactor body and the expansion pipe and including an inclined side wall.

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

14. The fluidized bed reactor according to claim 11, wherein: The fluidized bed reactor further comprises: a reactor lower portion connected to the bottom of the reactor body, a fluid introduction portion for injecting reaction gas into the reactor lower portion, and a fluid outflow portion connected to the expansion pipe and discharging the reaction gas.

15. The fluidized bed reactor according to claim 14, wherein: The fluidized bed reactor further includes a dispersion plate separating the reactor lower portion and the reactor body.

Images