KR101271669B1 - Method for reusing valuable metal of used battery - Google Patents

Abstract

The present invention relates to a method for recycling valuable metals of a waste battery, comprising: obtaining a valuable metal powder including lithium, nickel, cobalt, and manganese from a waste battery; Acid leaching the valuable metal powder in a reducing atmosphere to obtain a leaching solution; Obtaining hydroxide, lithium carbonate (Li ₂ CO ₃ ) and nickel, cobalt and manganese from the leaching solution.

Description

Recycling valuable metals of waste batteries {Method for reusing valuable metal of used battery}

The present invention relates to a method for recycling valuable metals in a waste battery.

Recently, the use of a battery pack type battery including a plurality of unit battery cells is increasing. The battery pack includes a plurality of battery modules electrically connected to each other, and the battery module includes a plurality of battery cells electrically connected to each other.

Such battery packs are widely used in electric vehicles (EVs) or hybrid electric vehicles (HEVs) requiring large electric capacity.

EV to HEV is in the spotlight as a means to solve the climate change problem caused by the greenhouse effect, which is a global environmental problem, and the number of production is expected to increase rapidly.

The battery cells used in EV to HEV use a lot of lithium-ion batteries, in which LiNi _x Co _y Mn _z O ₂ form is used as a positive electrode active material.

However, waste battery packs generated by electric vehicles are expected to increase rapidly in the future, but there is no method for recycling cathode active materials.

It is an object of the present invention to provide a method for recycling valuable metals in a waste battery.

An object of the present invention is to obtain a valuable metal powder containing lithium, nickel, cobalt and manganese from the waste battery in the valuable metal recycling method of the waste battery; Acid leaching the valuable metal powder in a reducing atmosphere to obtain a leaching solution; It is achieved by the step of obtaining a hydroxide and lithium carbonate (Li ₂ CO ₃ ) of nickel, cobalt and manganese from the leaching solution.

The method may further include obtaining a cathode active material in the form of LiNi _x Co _y Mn _z O ₂ by mixing and heat treating the hydroxide and the lithium carbonate.

The leaching solution can be obtained using 1.5 M to 4 M sulfuric acid and 4.5 vol% to 10 vol% hydrogen peroxide simultaneously and at 50 ° C. to 80 ° C.

The hydroxide can be obtained by adjusting the pH of the leaching solution.

After the leaching solution is obtained, the method may further include removing at least one impurity of copper, aluminum, and iron by adjusting the pH, and the pH of obtaining the hydroxide may be higher than the pH of the impurity removing step.

The pH of the step of obtaining the hydroxide may be 10 to 13, the pH of the impurity removal step may be 5.5 to 6.5.

The lithium carbonate may be obtained by carbonating lithium from the remaining filtrate after recovering the hydroxide.

After obtaining the leaching solution, it may further comprise the step of adjusting the concentration of each of the nickel, manganese and cobalt in the leaching solution.

The waste battery includes a plurality of battery modules electrically connected to each other, the battery module includes a plurality of battery cells electrically connected to each other, and the battery cell includes lithium ions using LiNi _x Co _y Mn _z O ₂ as a cathode active material. Battery type, the step of obtaining the valuable metal powder; Disassembling the waste battery to obtain the battery cell; Discharging the battery cell; The method may include recovering the valuable metal powder by pulverizing at least a portion of the battery cell and separating the particles.

The discharge may be performed in a discharge solution, and after the discharge, may further include dehydrating and drying the battery cell.

After the discharge, the method may further include separating the battery cell into a positive electrode structure, a negative electrode structure, and a separator, and the grinding and particle size separation may be performed on the positive electrode structure.

The anode structure, the aluminum foil; It may include the cathode active material which is fixed to the aluminum foil.

The grinding and particle size separation, lithium, nickel, cobalt and manganese may be recovered to 95% or more, aluminum may be recovered to 15% or less.

The waste battery can be obtained in a hybrid electric vehicle.

An object of the present invention is a method for recycling valuable metals of a waste battery, the method comprising: discharging a lithium ion battery type battery cell using LiNi _x Co _y Mn _z O ₂ as a cathode active material; Separating the battery cell into a positive electrode structure, a negative electrode structure, and a separator including the positive electrode active material; Grinding the cathode structure and separating the particle size to obtain a valuable metal powder including lithium, nickel, cobalt, and manganese; Acid leaching the valuable metal powder in a reducing atmosphere to obtain a leaching solution; It can be achieved by including a step of obtaining the hydroxides and lithium carbonate (Li ₂ CO ₃ ) of nickel, cobalt and manganese from the leaching solution.

The method may further include obtaining a cathode active material in the form of LiNi _x Co _y Mn _z O ₂ by mixing and heat treating the hydroxide and the lithium carbonate.

The leaching solution may be obtained at 50 ° C. to 80 ° C. using 1.5 M to 4 M sulfuric acid and 4.5 vol% to 10 vol% hydrogen peroxide simultaneously.

The hydroxide can be obtained by adjusting the pH of the leaching solution.

After the leaching solution is obtained, further comprising the step of adjusting the pH to remove at least one impurity of copper, aluminum and iron, the pH of the step of obtaining the hydroxide is 10 to 13, the pH of the impurity removal step is 5.5 to 6.5.

The lithium carbonate may be obtained by carbonating lithium from the remaining filtrate after recovering the hydroxide.

According to the present invention, a method for recycling valuable metals of a waste battery is provided.

1 is a process chart showing one method of manufacturing a cathode active material according to the present invention;
2 is a process chart showing another method of manufacturing a cathode active material according to the present invention;
3 is a process chart showing the valuable metal recovery method according to the present invention,
4 shows a state of separating the battery module from the waste battery pack,
Figure 5 illustrates the electrical connection of the battery module in the waste battery pack,
6 shows a state in which a battery cell is separated from a battery module,
7 shows a substrate separated from the battery module,
8 shows a frame separated from the battery module,
9 illustrates a battery cell separated from a battery module,
10 shows a state during battery cell discharge,
11 shows a discharge solution after discharge of the battery cell,
Figure 12 shows the voltage change during the discharge process of the battery cell when the discharge solution is not replenished,
Figure 13 shows the voltage change in the discharge process of the battery cell when replenishing the discharge solution,
14 shows the drying rate when the discharged battery cells are dried after being dehydrated,
15 shows a drying rate when the discharged battery cells are dried without dehydration,
16 shows discharged and dried battery cells,
17 is a view showing a negative electrode structure separated from the discharged and dried battery cells,
18 is a view showing a positive electrode structure separated from the discharged and dried battery cells,
19 shows the concentration of the anode structure by the grinding time and particle size,
Figure 20 shows the concentration of each valuable metal by grinding time when separated by -8mesh,
Figure 21 shows the concentration of each valuable metal by grinding time when separated by -18mesh,
Figure 22 shows the concentration of each valuable metal by grinding time when separated by -40mesh,
Figure 23 shows the concentration of each valuable metal by grinding time when separated by -65mesh,
24 shows leaching behavior of the valuable metal powder according to sulfuric acid concentration,
Figure 25 shows the leaching behavior of the valuable metal powder according to the sulfuric acid concentration,
Figure 26 shows the leaching behavior of valuable metal powder according to leaching temperature,
Figure 27 shows the precipitation rate in the process of removing impurities according to pH,
28 shows coprecipitation behavior according to pH,
29 shows the XRD results of the ternary hydroxide obtained in the experiment,
30 shows an SEM image of a ternary hydroxide obtained in an experiment,
Figure 31 shows the XRD results of the lithium carbonate obtained in the experiment.

Valuable metal powder in the present invention can be obtained in a waste battery (waste battery pack) for electric vehicles, especially hybrid vehicles (HEV), but is not limited thereto.

The waste battery pack includes a plurality of battery modules electrically connected, and the battery module includes a plurality of battery cells electrically connected. The battery cell is located in an aluminum case and includes a positive electrode structure, a separator, an electrolyte, and a negative electrode structure.

1 is a process chart showing one method of the positive electrode active material according to the present invention.

First, a valuable metal powder is prepared from the waste battery pack (S10). This process is described in detail below. Valuable metal powders include lithium, nickel, manganese and cobalt. In addition, aluminum is included with it, and copper and iron may be included in trace amounts. The composition of the valuable metal powder is somewhat different depending on the make and model of the battery cell.

Thereafter, the valuable metal powder is reduced and leached (S20). In this process, an acid solution and a reducing agent are added to prepare a leaching solution in which valuable metals are dissolved. Sulfuric acid solution may be used as the acid solution, and hydrogen peroxide may be used as the reducing agent. As the reducing agent, H ₂ , H ₂ S, NH ₃ and N ₂ H ₄ may be used.

In the reduction leaching, the concentration of sulfuric acid may be 1.5M to 4M, and specifically 2M. If it is less than 1.5M, the leaching rate can be less than 90%. If it is more than 4M, sulfuric acid consumption increases without improving the leaching rate.

The concentration of hydrogen peroxide may be 4.5 vol% to 10 vol%, specifically 5 vol%. If it is less than 4.5 vol%, the leaching rate can be less than 90%, and if it is more than 10 vol%, only hydrogen peroxide is used without increasing the leaching rate.

Leaching temperature may be 50 ℃ to 80 ℃, specifically may be 60 ℃. If the temperature is 50 ° C or less, the leaching rate may be 90% or less. If the temperature is 80 ° C or higher, the reaction temperature may be increased without improving the leaching rate.

Next, by increasing the pH of the leaching solution to remove impurities such as aluminum, iron and copper (S30). The pH can be increased by the addition of a base solution, for example NaOH, to about 5 to 10, specifically 5.5 to 6.5, more specifically 6. The hydroxides of these impurities are removed because the solubility is very low when the pH is increased. Solubility product (Ksp) of Fe (OH) ₃ is 1.58 * 10 ^-39, so the solubility of Fe (OH) ₃ at pH 6 is very small, 8.8 * 10 ^-22 g / 100g H ₂ O and Cu (OH) Solubility product (Ksp) of ₂ is 4.79 * 10 ^-20, so the solubility of Cu (OH) ₂ is 3.0 * 10 ^-3 g / 100g H ₂ O and solubility product (Ksp) of Al (OH) ₃ Since 3.16 * 10 ^-34 , the solubility of Al (OH) ₃ is 8.5 * 10 ^-15 g / 100g H ₂ O. Therefore, most of Fe, Cu and Al are removed before pH 6.

If pH is less than 5.5, Al removal rate is low. If pH is more than 6.5, other valuable metals can be removed together.

Next, impurities are removed and the pH of the recovered leaching solution is further increased to obtain hydroxides of nickel, manganese and cobalt (S40). At higher pH, nickel, manganese, and cobalt precipitate as aquatic products, but remain in the lithium ion state. This is because the solubility of each metal hydroxide is different, and for reference, the solubility of each metal ion in the pH 13 conditions of the precipitate is as follows. The solubility of LiOH at 20 ° C. is as high as 12.3 g / 100 g H ₂ O, while Mn (OH) ₂ is 1 * 10 ⁻³ g / 100 g H ₂ O at 20 ° C. and Ni (OH) ₂ is 3.1 * at 25 ° C. This is because 10 ^-9 g / 100g H ₂ O, Co (OH) ₂ is small at 8 * 10 ^-6 g / 100g H ₂ O at 25 ° C.

The pH of the coprecipitation process for obtaining the hydroxide may be 10 to 13. If the pH is less than 10, the coprecipitation rate is lowered, and the recovery of valuable metals is reduced. If the pH is higher than 13, the chemical usage is increased without further coprecipitation rate improvement.

The obtained hydroxide is in the form of Ni _x1 Co _y1 Mn _z1 (OH) ₂ , where the content ratio between the metals may be the same as or different from the final active material. In particular, after obtaining the hydroxide, the concentration ratio is described later, the content ratio between each metal is different from the hydroxide and the final active material.

Lithium is separated from the remaining filtrate in the process of obtaining a hydroxide to carbonate lithium to obtain lithium carbonate (S50). In the carbonation process, Na ₂ CO ₃ or K ₂ CO ₃ , H ₂ CO _3, etc. are added in an equivalent ratio to the number of mol of lithium in the solution, followed by stirring to recover a precipitate in the form of Li ₂ CO ₃ .

Finally, when the obtained hydroxide and lithium carbonate are mixed and heat treated, a cathode active material in the form of LiNi _x Co _y Mn _z O ₂ is obtained (S60). Heat treatment is carried out at 900 ℃ ~ 1000 ℃ conditions and the product obtained after the heat treatment can be prepared into particles of 5 ~ 20 ㎛ through fine powdering. However, the use of hydroxide and lithium carbonate is not limited to the production of a cathode active material.

Figure 2 shows another method for producing a cathode active material according to the present invention.

Different from Figure 1 is to extract the solvent after reduction leaching (S21) to separate nickel, manganese, cobalt separately (S22). Through this process, impurities other than nickel, manganese and cobalt can be further lowered. By solvent extraction using a Phosphinic acid-based, Phosphoric acid-based, Phosphonic acid organic solvent for acid-based Li is separated / recovered as Raffinate and detached using a sulfuric acid solution was extracted only Ni, Mn, Co with an organic solvent, NiSO _4, Recovered with a mixed solution of MnSO ₄ , CoSO ₄ . This separates and recovers Li, Ni, Mn, and Co.

In the above-described method, a process of adjusting the concentration of each metal component may be added before reduction leaching, after reduction leaching, after removing impurities, after obtaining a hydroxide, and the like to obtain a desired component ratio. In the case of insufficient components through the component analysis of the recovered solution, the composition of Ni, Mn, Co in the solution is uniformly adjusted by using manganese sulfate, cobalt sulfate, and nickel sulfate salt. Through this process, different manufacturing specifications of different lithium ion battery ternary cathode active materials manufacturers can be met. Such a metal component adjustment may be performed to simplify the process conditions by making different component ratios similar for different battery packs.

Hereinafter, a process of obtaining the valuable metal powder from the waste battery pack will be described with reference to FIG. 3.

First separate the waste battery pack into a battery module (S100). This process checks the voltage of the battery pack and removes the electrical connections between the battery modules. Also remove the screws that connect between the battery modules. This can be done manually.

Next, the battery module is separated into battery cells (S200). The battery module includes a circuit board, a frame and a battery cell, and the circuit board and the frame are recycled separately. This can also be done manually.

Next, the battery cells are discharged for work stability (S300). After the discharge is completed, the subsequent valuable metal recovery process can be safely performed in the atmosphere rather than in an inert atmosphere. The discharge can be made in the discharge solution. Distilled water may be used as the discharge solution. The completion of the discharge can be confirmed by decreasing the voltage over time.

After that, the discharged battery cells are dehydrated and dried (S400). Drying may be at 60 ° C to 90 ° C. The battery cell recovered after the discharge is directly put into the drying process or the drying time is reduced when the dehydration process, the drying time may be 10 hours to 30 hours. The battery cell may be in an aluminum case, which may be removed before discharging.

Meanwhile, the electrolyte in the battery cell is mostly removed during the discharge process, and some of the remaining electrolyte is also volatilized and removed during the drying process.

Next, the positive electrode structure is separated from the battery cell (S500). Each battery cell consists of a positive electrode structure, a separator, and a negative electrode structure, which are separated by hand. The anode structure is composed of an aluminum foil and a cathode active material fixed thereto. The cathode active material may be LiNi _x Co _y Mn _z O ₂ . The separator may be made of polyethylene or polypropylene. The negative electrode structure may be made of copper foil and graphite fixed thereto. Here, the valuable metal to be recovered is a metal constituting the positive electrode active material (Li, Ni, Mn, Co) and the obtained positive electrode active material is transferred to a process for further treatment.

The obtained anode structure is then pulverized and the particle size is separated (S600).

Grinding and particle size separation is preferably such that the desired valuable metals are recovered by 95% or more, and unwanted metals, particularly aluminum, by 15% or less. Even if it is pulverized, the particle size of the components constituting the positive electrode active material is usually smaller than that of the crushed aluminum foil, so that the separation particle size can be reduced to lower the aluminum content. The separation condition can be 65 mesh or less.

In another recovery method according to the present invention, the cathode structure is pulverized and the particle size is separated together with the anode structure. At this time, the active material of the negative electrode structure may be removed by a discharge process, etc., the separator may also be removed. This method can be used when the battery cell is in the form of an anode structure / cathode structure / anode structure or in the form of a cathode structure / anode structure / anode structure. At this time, in addition to aluminum, copper of the negative electrode structure may be included as an impurity. When it is difficult to lower the content of copper, only the recovery rate of aluminum may be 15% or less.

Hereinafter, the present invention will be described in more detail by way of examples. The examples are intended to illustrate the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention is not limited to the examples.

The waste battery pack used in the experiment was used for a golf cart and consists of six unit battery modules, each of which consists of ten battery cells.

1. Disconnect with battery module

Figure 4 is a photograph of separating the battery module to the waste battery pack. The battery module has a two-layer structure, and three battery modules are located on each floor. The battery modules of the upper layer and the lower layer are connected in series, respectively, and the battery modules of the upper layer and the lower layer are also connected in parallel.

In order to reliably disassemble each battery module from the battery pack, the voltage of the battery pack was checked, and the connected wires were cut one by one without cutting at a time.

The battery modules in the waste battery pack are connected as shown in FIG. 5, and first, the connection bars of the serial parts are disassembled and then the connection bars of the parallel parts are dismantled. The battery module was removed from the battery pack.

The above work was performed by hand.

2. Disconnect into battery cell

The upper and lower parts of the disassembled battery module are divided into acrylic plates and substrates. When the cell is disassembled, the cells are stacked in layers so that the contacts of the upper and lower cells should not be joined to prevent short circuits. .

Each battery cell is fixed with double-sided tape to prevent separation between the frame and the frame between the cell and the cell that fixes the cell, so the frame is removed first, and then each contact is cut with an insulating scissors. To dismantle each battery cell.

6 shows a separation operation using insulating scissors. FIG. 7 illustrates a separated substrate, FIG. 8 illustrates a separated frame, and FIG. 9 illustrates a separated battery cell. In FIG. 9 the battery cell is wrapped in an aluminum case.

3. Discharge

The battery cell from which the aluminum case was removed was put in distilled water and discharged.

FIG. 10 is a state during discharge, and FIG. 9 is a state after completion of discharge.

12 and 13 show the voltage change during discharge. FIG. 12 illustrates a case in which the discharge solution is not replenished and FIG. 13 illustrates a case in which the discharge solution is replenished.

It was confirmed that there was no significant difference in the voltage change when the discharge solution was not replenished and when replenished. The behavior of the voltage change was found to be the highest when the response was the lowest in 5 minutes, and both discharge reactions were completed within 70 minutes.

After discharging, the sample was dissolved using aqua regia (HCl: HNO ₃ = 3: 1) for the component analysis of the separated and recovered battery cells, and then analyzed by ICP analysis.

Co Mn Ni Li Al Cu Fe One 4.9 11.9 12.5 2.3 7.2 13.0 0.04 2 4.9 12.0 12.1 2.2 7.2 12.7 0.04 3 5.0 11.7 12.3 2.2 7.1 12.8 0.04 4 4.7 11.1 11.4 2.1 6.8 12.2 0.04 5 5.7 13.2 13.4 2.5 8.1 14.5 0.04 Ave. 5.1 12.0 12.3 2.3 7.3 13.1 0.04

Analysis result of chemical composition of discharged unit battery cell (%)

LiNi _x Mn _y Co _z O ₂ Li Ni Mn Co Atomic weight 6.94 58.70 54.94 58.93 content (%) 2.26 12.34 11.97 5.05 Mole ratio 0.33 0.21 0.22 0.09 ratio One 0.6 0.7 0.3

Expected Proportion of Cathode Active Material

As can be seen in Table 1 and Table 2 it was confirmed that the valuable metal in the sample consists of Co, Mn, Ni, Li, Al, Cu, and also contained a trace amount of Fe. The content of each element was found to be 5.1% Co, 12% Mn, 12.3% Ni, 2.3% Li, 7.3% Al, 13.1% Cu. The molar ratio of Li: Ni: Mn: Co of LiNi _x Mn _y Co _z O _{2 as} a positive electrode active material was 1: 0.6: 0.7: 0.3. Here, x + y + z may be 1, but may be greater than 1 when spinel-based LiMnO ₂ is mixed to improve instantaneous output power and thermal stability.

4. Dehydration and Drying

The battery cells were dried at 80 ° C. after discharge. 14 and 15 show the drying efficiency according to the drying time. 14 illustrates a case of drying after dehydration using a dehydrator, and FIG. 15 illustrates a case of drying without dehydration.

In the case of dehydration as shown in Figure 14, the weight of the sample was almost no change in weight after 10 hours it was confirmed that the sample is dried. On the other hand, if you do not dehydrate as shown in Figure 15, it was confirmed that the drying is finished as the drying weight is constant after about 24 hours.

5. Separation of anode structure

FIG. 16 is a view of a battery cell in which discharge and drying are completed. FIG. By manual operation, the battery cells were separated into a positive electrode structure, a separator, and a negative electrode structure.

17 shows a separated cathode structure, and FIG. 18 shows a separated anode structure.

In the negative electrode structure, graphite as the negative electrode active material was easily separated from the copper foil as the negative electrode. Therefore, the cathode structure is expected to be immediately recycled by the company that manufactures them. The separator is also ready for recycling.

On the other hand, in the anode structure, separation of the anode aluminum foil and the cathode active material is not observed. Therefore, additional work is required to recover valuable metals from the anode structure.

6. Grinding and particle size separation

19 shows concentration efficiency according to particle size according to grinding conditions for the anode structure.

30 g of the recovered anode structure was crushed for 30 seconds, and the concentrations of +8 mesh, -8 + 18 mesh, -18 + 40 mesh, -40 + 65 mesh and -65 mesh were 20%, 22% and 8%, respectively. In addition, the contents of + 8mesh and -8 + 18mesh products were also significantly higher than those of -65mesh product, where the cathode active material was concentrated to 7% and 41.5%.

When the grinding was carried out for 5 minutes, the particle size results were +8 mesh, -8 + 18 mesh, -18 + 40 mesh, -40 + 65 mesh, and -65 mesh. In comparison with the experimental results of 30 seconds of grinding, 8% and 83%, the contents of +8 mesh and -8 + 18mesh were significantly reduced, and the contents of -65mesh were increased. .

20 to 23 show the concentration of valuable metals by grinding time and particle size. 20 shows -8mesh, FIG. 21 shows -18mesh, FIG. 22 shows -40mesh, and FIG. 23 shows -65mesh.

20 to 23, when the mesh is large, the concentration ratio is close to 100%, but the content of Al, which is an unwanted impurity, was high, but the ternary cathode active material (Co, Ni, Mn) was 95 at -65mesh separation conditions. It was possible to recover more than% concentration, and it was possible to remove more than 88% of Al as an impurity.

7. Reduction leaching

Reduction leaching was carried out on -65mesh valuable metal powder. In a 1000-neck five-neck Pyrex reactor, a leaching solution was stirred using a Teflon impeller with a diameter of 120 mm, and hydrogen peroxide was injected into the solution by installing a Teflon tube.

The solid solution ratio of the leaching solution and the sample was 1:10. After the sample was added, the solid solution was stirred at 300 rpm, and the concentration of sulfuric acid, hydrogen peroxide and reaction temperature were changed. The sampled reaction solution was analyzed for the concentration of valuable metals using an inductively coupled plasma spectrophotometer.

Sulfuric acid concentration change

The concentration of sulfuric acid was changed in the reaction temperature of 60 ℃, stirring speed 300 rpm, high / liquid concentration 100 g / L, H 2 O 2 added 5 vol.% Conditions are shown in Figure 24.

As shown in FIG. 24, at a concentration of 0.5 M H2SO4, Li showed a low leaching rate of less than 81.3%, Co, Mn, and Ni, but less than 55%, but as the concentration of sulfuric acid increased, almost 100% of Co, Mn, Leaching of Ni and Li was achieved.

Reducing agent concentration change

Leaching of the positive electrode active material with the change of the concentration of hydrogen peroxide was observed under the reaction temperature of 60 ℃, stirring speed 300 rpm, solid / liquid concentration 100 g / L, H 2 SO 4 2M conditions.

As shown in FIG. 25, the low leaching rate of 71.3% Co, 69.6% Mn, 73.4% Ni, and 79.7% Li is shown at 3 vol% H2O2 concentration, but when H2O2 is added 5vol% or more, Co, Mn, Ni, and Li are 99%. Over leaching efficiency was shown.

Leaching temperature change

The leaching rate of the positive electrode active material was observed while varying the reaction temperature under the condition of H 2 SO 4 2 M, solid / liquid concentration 100 g / L, stirring speed 300 rpm, H 2 O 2 addition amount 5 vol%.

As can be seen in FIG. 26, when the reaction temperature is 25 ° C., the leaching rate was low as 70.4% Co, 68.4% Mn, 71.4% Ni, 86.1% Li, but when the reaction temperature is increased, the leaching rate increases to 60 ° C. It was found that the positive electrode active material was leached near 100%.

Table 3 shows the concentrations of each component under the conditions of 100 g / L, 2M H 2 SO 4, 5 vol.% H 2 O 2, 300 rpm, 60 ° C., and 2 h. The leaching efficiency was more than 98% for Co, Mn, Ni and Li. Then, the experiment was conducted on the samples in Table 3.

ingredient Co Mn Ni Li Concentration (g / L) 10.39 14.47 16.07 12.25 Leaching Efficiency (%) 98.4 98.9 98.8 98.6

Of Sulfuric Acid Reduction Solution of -65mesh Product

8. Removal of impurities in leaching solution

In order to remove the remaining impurities (Al) in the leaching solution, 4M NaOH was added to investigate the precipitation behavior according to the pH change.

At pH 6 or higher as shown in FIG. 27, more than 96% could be removed. The precipitation rate increased from pH 4, and above pH 6, the precipitation rate of valuable metals increased rapidly. At pH 6, valuable metal losses were 4.5% Co, 2.2% Mn, 6.0% Ni, and 96% Al was removed. Thereafter, the experiment was performed on the sample obtained at pH 6.

9. Recovery of Ternary Hydroxide

Coprecipitation experiments to obtain ternary hydroxide were carried out in a beaker of 5000ml capacity. The leaching solution was agitated (300rpm) using a Teflon impeller made of 120 mm in diameter, and a NaOH solution of about twice the concentration of the raw material, and a NH ₄ OH solution used as a coprecipitation agent were prepared.

500 mL of distilled water adjusted to pH 9 with ammonia water was added into a beaker at a constant flow rate using a metering pump in a 5000 ml beaker. The pH was adjusted in the reactor during the reaction, and the solution was stirred at a stirring speed of 300 rpm for 80 hours. During the coprecipitation experiment.

As shown in FIG. 28, co-precipitation behavior was examined between pH 9 and pH 12 by adjusting NH ₄ OH and NaOH. After co-precipitation, the positive electrode active material was almost precipitated in the filtrate at pH 11 or above.

ingredient Co Mn Ni Li Experimental Extract 17930 19270 17950 5570 pH 9 2386.4 2302.9 1779.1 4893.6 pH 10 15.3 553.8 2.5 4375.4 pH 11 0.3 0.0 0.5 4225.8 pH 12 0.3 0.0 0.5 4100.0

Valuable Metal Concentration According to pH (mg / L)

29 is a result of XRD analysis of the precipitate produced under the condition of pH 11 and compares the XRD diffraction pattern of the conventional ternary precursor and the precursor obtained through the present experiment, it can be seen that the peak is almost the same, the ternary cathode active material precursor It was confirmed that was prepared.

As a result of SEM analysis of the produced crystals, as shown in FIG. 30, the precipitates recovered after 72 hours of coprecipitation experiments at pH 11 were prepared as crystals of spherical particles having a diameter of about 13 μm. It was confirmed that the ternary hydroxide, which can be used as a cathode active material precursor of a lithium ion battery, was formed.

The experiment was subsequently carried out with a filtrate after obtaining a ternary hydroxide at pH 11.

10. Lithium Carbonate Recovery

50 mL of Na 2 CO 3 saturated solution (4 mol / L) was injected into the coprecipitation solution containing lithium. In the experimental method, the solution was reacted for 5 hours by adding Na 2 CO 3 solution while heating the solution at a stirring speed of 300 rpm in a beaker while heating the solution at 90 ° C., and then Li was recovered by precipitating, filtration and washing with Li 2 CO 3.

The valuable metal concentrations of the precipitates are shown in Table 5 and it can be confirmed that 92% of lithium was precipitated.

Co Mn Ni Li Al Cu Filtrate after copulation 0.1 - - 5360.0 1.7 0.3 Filtrate after Li ₂ CO ₃ precipitation 1.45 - - 416.8 0.04 0.33

Valuable metal concentration in solution before and after precipitation for recovery of lithium carbonate (mg / L)

FIG. 31 shows that the peaks are almost identical when the XRD analysis results of precipitates generated and Li recovered from the filtrate remaining after co-precipitation with XRD of Li ₂ CO ₃ and precipitates.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (20)

In the valuable metal recycling method of waste batteries,
Obtaining a valuable metal powder containing lithium, nickel, cobalt, and manganese from a waste battery;
Acid leaching the valuable metal powder in a reducing atmosphere to obtain a leaching solution;
Comprising the steps of obtaining a hydroxide, lithium carbonate (Li ₂ CO ₃ ) and nickel, cobalt and manganese from the leaching solution,
After obtaining the leaching solution,
adjusting the pH to remove impurities of at least one of copper, aluminum and iron,
PH of the step of obtaining the hydroxide is higher than the pH of the impurity removal step. The method of claim 1,
And mixing and heat treating the hydroxide and the lithium carbonate to obtain a cathode active material in the form of LiNi _x Co _y Mn _z O ₂ . 4. The method according to any one of claims 1 to 3,
The leaching solution is,
Obtained at 50 ° C. to 80 ° C. using 1.5 M to 4 M sulfuric acid and 4.5 vol% to 10 vol% hydrogen peroxide simultaneously. delete delete The method of claim 1,
The pH of the step of obtaining the hydroxide is 10 to 13, characterized in that the pH of the impurity removal step is 5.5 to 6.5. 4. The method according to any one of claims 1 to 3,
Wherein said lithium carbonate is obtained by carbonating lithium from the filtrate remaining after recovering said hydroxide. 4. The method according to any one of claims 1 to 3,
After obtaining the leaching solution,
And adjusting the concentration of each of nickel, manganese and cobalt in the leaching solution. 4. The method according to any one of claims 1 to 3,
The waste battery includes a plurality of battery modules electrically connected to each other, the battery module includes a plurality of battery cells electrically connected to each other, and the battery cell includes lithium ions using LiNi _x Co _y Mn _z O ₂ as a cathode active material. Battery type
Obtaining the valuable metal powder is;
Disassembling the waste battery to obtain the battery cell;
Discharging the battery cell;
Pulverizing and separating particle sizes of the battery cells to recover the valuable metal powder. 10. The method of claim 9,
The discharge is made in the discharge solution,
After the discharge, further comprising dehydrating and drying the battery cell. The method of claim 10,
After the discharge,
Separating the battery cell into a positive electrode structure, a negative electrode structure and a separator,
The pulverization and particle size separation is characterized in that performed on the anode structure. The method of claim 11,
The anode structure,
Aluminum foil;
And the cathode active material fixed to the aluminum foil. The method of claim 12,
The grinding and particle size separation,
Lithium, nickel, cobalt and manganese are recovered at least 95%, aluminum is carried out to recover less than 15%. The method of claim 1,
The waste battery,
Method obtained by the hybrid electric vehicle. delete delete delete delete delete delete

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