KR102405778B1 - Preparing method of lithium carbonate by recycling lithium from wasted electrode material of lithium secondary battery - Google Patents

Abstract

The present invention comprises the steps of: (S1) hydrolyzing the mother liquid by adding sodium hydroxide (NaOH) to the mother liquid containing lithium; (S2) adding hydrochloric acid (HCl) to the resultant of step (S1) to form lithium chloride (LiCl); (S3) concentrating the resultant of step (S2) to increase the concentration of lithium ions in the resultant of step (S2); and (S4) adding sodium carbonate (Na ₂ CO ₃ ) to the resultant of step (S3) to form lithium carbonate (Li ₂ CO ₃ ). It relates to a method for producing lithium.

Description

Method for manufacturing lithium carbonate by recovering lithium from waste electrode material of a lithium secondary battery

The present invention relates to a method for manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery, and more particularly, nickel (Ni), cobalt (Co) and manganese ( Mn), using the remaining lithium filtrate (undiluted solution) after separation, relates to a method for producing lithium carbonate that can further improve the lithium recovery rate.

As the usage of lithium secondary batteries increases with the development of the IT industry, the amount of waste lithium secondary batteries and waste scraps generated in the process is increasing day by day. The trend is to use ternary (nickel, cobalt, manganese) oxides having superior battery performance compared to pure materials for the cathode, which accounts for more than 60% of the cost of such lithium secondary batteries. All of these expensive metals depend on imports, and the technology to recover the metals thrown away as waste is being promoted as a national task.

Due to the explosive demand for lithium secondary batteries and the shortening of the use cycle of small digital home appliances, the emission of lithium secondary batteries is rapidly increasing. When such a lithium secondary battery has reached the end of its lifespan, if the waste material is used, problems such as environmental pollution can be reduced, and the cost of raw materials for the production of the lithium secondary battery can also be reduced. In addition, since the defective waste battery scrap generated during the lithium secondary battery manufacturing process or the lithium secondary battery waste scrap discarded after use contains useful metals such as nickel, cobalt, and manganese, in recent years, to recover and recycle these useful resources Technology development is actively underway.

On the other hand, in the case of Korea, it is currently dependent on imports of lithium carbonate, a key raw material for lithium secondary batteries, and the price of lithium carbonate is expected to surge as the demand for lithium carbonate increases in the future. In the case of Korea, securing a technology for recovering and reusing lithium is being promoted as a national task, but technology that effectively increases the recovery rate of lithium has not been developed so far.

An object of the present invention is to use the remaining lithium filtrate (undiluted solution) after separating nickel (Ni), cobalt (Co) and manganese (Mn) components from the waste electrode material of a lithium secondary battery, and further improve the lithium recovery rate It is to provide a method for producing lithium carbonate that can be

In order to achieve the above object, in the method for manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to an aspect of the present invention, (S1) sodium hydroxide (NaOH) is added to a mother liquid containing lithium to hydrolyze the mother liquor; (S2) adding hydrochloric acid (HCl) to the resultant of step (S1) to form lithium chloride (LiCl); (S3) concentrating the resultant of step (S2) to increase the concentration of lithium ions in the resultant of step (S2); and (S4) adding sodium carbonate (Na ₂ CO ₃ ) to the resultant of step (S3) to form lithium carbonate (Li ₂ CO ₃ ).

In this case, it is performed after the step (S4), and (S5) may further include the step of washing the lithium carbonate formed as a result of the step (S4) with distilled water.

Here, in step (S5), the lithium carbonate may be washed with distilled water 5 to 25 times the weight of the lithium carbonate.

In addition, it is performed after the step (S5), and (S6) may further include the step of drying the lithium carbonate formed as a result of the step (S5).

In addition, the pH of the resultant after step (S1) may be 10.5 to 11.5.

In addition, the step (S3) may be made through a vacuum evaporator.

And, to be performed after step (S4), (S4-a) the step of collecting the remaining filtrate except for the lithium carbonate in the result of step (S4), and mixing the resultant with the result of step (S2) is more may include

In addition, to be performed after step (S5), (S5-a) collecting the remaining washing solution except for the lithium carbonate in the result of step (S5) and mixing with the result of step (S2) may include more.

On the other hand, in the method for manufacturing lithium carbonate by recovering lithium from the waste electrode material of a lithium secondary battery according to another aspect of the present invention, (S10) the filtrate remaining except for the lithium carbonate in the result of the step (S4), collecting the remaining washing solution except for the lithium carbonate in the result of the step (S5); (S20) concentrating the resultant of the step (S10) to increase the concentration of lithium ions in the resultant of the step (S10); (S30) adding sodium carbonate (Na ₂ CO ₃ ) to the resultant of step (S20) to form lithium carbonate (Li ₂ CO ₃ ); (S40) washing the lithium carbonate formed as a result of the step (S30) with distilled water; and (S50) drying the lithium carbonate formed as a result of the step (S40).

According to the present invention, lithium carbonate can be manufactured by separating nickel (Ni), cobalt (Co) and manganese (Mn) components from the waste electrode material of a lithium secondary battery and recycling the remaining lithium filtrate (undiluted solution).

In addition, by including the step of forming lithium chloride having high solubility in water during the process of the present invention, the recovery rate of lithium carbonate, that is, the recovery rate of lithium can be further increased.

Furthermore, the recovery rate of lithium can be further maximized by recycling the filtrate or washing solution generated during the process of the present invention.

1 is a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to another embodiment of the present invention.
3 to 6 are each a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to another embodiment of the present invention.
7 is a graph showing the lithium recovery rate and sodium concentration according to the ratio of the washing solution in the washing process according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Accordingly, the configuration described in this specification is only the most preferred embodiment of the present invention and does not represent all of the technical idea of the present invention, so there are various equivalents and modifications that can be substituted for them at the time of the present application. It should be understood that

A method of recycling the waste electrode material of a lithium secondary battery to separate nickel (Ni), cobalt (Co) and manganese (Mn) components, which are valuable metals, will be described as follows.

First, the waste electrode material oxide powder is leached with acid and filtered (step (a)). When the acid leaching reaction is completed, filtration may be performed to obtain a filtrate.

In step (a), hydrochloric acid and hydrogen peroxide are introduced into the reactor containing the waste electrode material, and the leaching process can be performed at a temperature of 75° C. to 85° C. for 180 minutes to 300 minutes, and the amounts of hydrochloric acid and hydrogen peroxide can be adjusted, respectively. have. As the acid, in addition to hydrochloric acid, sulfuric acid or the like can be used.

After the leaching process, the amounts of hydrochloric acid and hydrogen peroxide may be adjusted so that the pH inside the reaction tank is 0.8 to 1.8. In particular, in this step, the leaching efficiency can be maximized by adjusting the concentration and input rate of hydrogen peroxide in order to remove the chemical resistance caused by the carbon and binder added in the electrode material manufacturing process.

In the process of manufacturing the electrode material of a lithium ion secondary battery, in order to maintain or improve the battery characteristics, it undergoes complicated processes such as firing, carbon and other metal oxides, and thermal fusion after adding a binder. Ash has chemical resistance, which may act as a hindrance factor in the recovery of lithium and valuable metals by leaching with acid.

In the process of leaching with acid, the chemical resistance of the waste electrode material can be solved by supplying hydrogen peroxide at a certain concentration and rate. For this reason, the recovery rate of lithium and valuable metals can be increased by adjusting the concentration of hydrogen peroxide to 10 wt% to 35 wt% during acid leaching and adding 0.1 to 5 LPM (Liter Per Minute). Under high temperature (85±5° C.) to maintain the leaching reaction, a significant amount of the hydrogen peroxide added is decomposed into H ₂ O or OH radicals prior to the redox reaction. Therefore, as for the input of hydrogen peroxide, lithium and valuable metals can be recovered with high efficiency only when a certain concentration of hydrogen peroxide is introduced at a constant rate throughout the acid leaching process.

Then, the leachate leached in step (a) is hydrolyzed and separated into an aqueous lithium solution and a carbonate cake (step (b)).

Step (b) may include adding an aqueous sodium carbonate solution having a sodium carbonate (Na ₂ CO ₃ ) content of 10 wt% to 25 wt% based on the total weight of the sodium carbonate aqueous solution into the reactor. At this time, the temperature inside the reaction tank may be 45° C. to 75° C., the pH may be 6.5 to 8.5, and the stirring speed may be 250 to 350 rpm.

In step (b), lithium is converted into solubilized lithium carbonate (Li ₂ CO ₃ (ℓ)), nickel, cobalt, and manganese are precipitated nickel carbonate (NiCO ₃ (s)), cobalt carbonate (CoCO ₃ (s)) ) and manganese carbonate (MnCO ₃ (s)), lithium is an aqueous solution in which lithium carbonate (Li ₂ CO ₃ (ℓ)) and lithium chloride (LiCl (ℓ)) are mixed, nickel, cobalt, manganese A lithium aqueous solution can be obtained by separating the silver into a carbonate cake.

In inducing the hydrolysis reaction, a sodium carbonate aqueous solution is added to the leaching filtrate at a temperature above room temperature, preferably 45° C. to 75° C. while stirring the leaching filtrate at 250 rpm to 350 rpm. , cobalt, and manganese can be reacted quantitatively with carbonate cake to separate them. Valuable metals can be recovered and purified through a separate process for nickel, cobalt, and manganese carbonate, and an aqueous lithium solution can be used for lithium carbonate synthesis.

Here, the aqueous lithium solution and the aqueous solution of the supernatant separated through pickling and water washing for the carbonate cake and the obtained lithium solution are used as the mother solution containing lithium of the present invention.

1 is a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to an embodiment of the present invention.

1, the present invention will be described in more detail.

First, sodium hydroxide (NaOH) is added to the mother liquid containing lithium to hydrolyze the mother liquid (step S1).

As described above, the mother liquid containing lithium may be a lithium filtrate (stock solution) remaining after the nickel (Ni), cobalt (Co) and manganese (Mn) components are separated from the waste electrode material of the lithium secondary battery.

Residual impurities such as nickel, cobalt, and manganese still remain in the mother liquid containing lithium, and purification is required to remove them. At this time, the sodium hydroxide may be added in an aqueous solution phase, and an aqueous sodium hydroxide solution having a sodium hydroxide content of about 33% by weight based on the total weight of the aqueous solution is added to the reaction tank to have a pH of about 10.5 to 11.5, more preferably It may be adjusted to around 11. This process may be performed at room temperature. Stirring may also be performed when the sodium hydroxide aqueous solution is added. Impurities such as nickel, cobalt, and manganese are precipitated as a solid cake, and the remaining nickel, cobalt, and manganese in the filtrate containing lithium can be removed by filtration using a vacuum filtration device.

Then, hydrochloric acid (HCl) is added to the resultant of step (S1) to form lithium chloride (LiCl) (step S2). In this case, 0.1 to 0.7 mol of hydrochloric acid may be added based on 600 g of the resultant of the step (S1) having a pH of 11.01. As hydrochloric acid is added, the maximum concentration of the mother liquor containing lithium increases, but when 0.5 mol or more is added, the pH becomes too low. Therefore, the optimal hydrochloric acid input is about 0.4 mol, and when the hydrochloric acid input is 0.4 mol, the maximum concentration of the mother liquor containing lithium is about 65.2%.

Here, as a method for increasing the concentration of the filtrate containing lithium, hydrochloric acid may be added to change to a lithium chloride form with high solubility in water.

Then, the resultant of step (S2) is concentrated to increase the concentration of lithium ions in the resultant of step (S2) (step S3).

In this case, in the step (S3), the concentration may be performed through a vacuum evaporator. The degree of vacuum during concentration is 120 to 160 mbar, preferably 130 to 150 mbar, more preferably about 140 mbar, and the reaction temperature is about 55 to 75 ℃, preferably 60 to 70 ℃, more preferably about 65 ℃. , The stirring speed may be fixed to 130 to 170 rpm, preferably 140 to 160 rpm, more preferably to about 150 rpm, but is not limited to the above numerical values.

Here, the time point at which crystals are formed during vacuum evaporation is considered as the maximum concentration rate, and the step (S3) is terminated at that point.

Then, sodium carbonate (Na ₂ CO ₃ ) is added to the resultant of step (S3) to form lithium carbonate (Li ₂ CO ₃ ) (step S4).

Here, the sodium carbonate (Na ₂ CO ₃ ) may be added as an aqueous solution, and an aqueous sodium carbonate solution having an amount of sodium carbonate of about 15% by weight based on the total weight of the aqueous solution may be added to the reaction tank.

When the reaction step of the present invention is performed as described above, the amount of lithium recovered from the mother liquid containing lithium can be further improved, and ultimately the amount of lithium carbonate produced can be maximized.

2 is a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to another embodiment of the present invention.

Referring to FIG. 2 , the method for manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to another aspect of the present invention is performed after step (S4). The method may further include washing the resulting lithium carbonate with distilled water (step S5).

Excess sodium ions coexist in the product after synthesizing lithium carbonate. Since sodium ions act as impurities in the product, the concentration of sodium ions must be reduced. In order to reduce the concentration of sodium ions, step (S5) is can be done

In this case, the lithium carbonate may be washed with distilled water 5 to 25 times the weight of the lithium carbonate. If the content of the distilled water is less than the numerical range, the recovery rate of lithium may be further increased, but there may be a problem that the concentration of sodium ions as an impurity is too high, and if the content of the distilled water exceeds the numerical range, sodium ions as impurities Although the concentration of is lowered, there may be a problem in that the recovery rate of lithium is also too low.

The reaction temperature during washing with water may be carried out at 95 ° C. or higher in consideration of the solubility of lithium carbonate, and the stirring speed may be fixed at 130 to 170 rpm, preferably 140 to 160 rpm, more preferably at about 150 rpm. , but is not limited only to the above numerical values.

3 is a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to another embodiment of the present invention.

Referring to FIG. 3 , which is performed after step (S5), drying the lithium carbonate formed as a result of step (S5) may be further included (step S6). Through the above step, moisture in the formed lithium carbonate can be removed, and if necessary, the dried lithium carbonate can be pulverized to produce a finished product of fine particles.

4 and 5 are flowcharts illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to still another embodiment of the present invention.

4 and 5, to be performed after the step (S4), the filtrate remaining except for the lithium carbonate in the result of the step (S4) is collected and mixed with the result of the step (S2) (Step S4-a) may be further included.

And, as performed after step (S5), collecting the remaining washing liquid except for the lithium carbonate in the resultant of step (S5) and mixing it with the resultant of step (S2) (step S5-a) may further include.

Conventionally, the filtrate remaining after forming lithium carbonate in step (S4) and the washing solution remaining after washing lithium carbonate in step (S5) were transferred to a wastewater treatment plant and discharged, but according to the above embodiment of the present invention, the By additionally reusing the filtrate and washing solution and mixing it with the resultant of step (S2), it was possible to further increase the recovery rate of lithium.

6 is a flowchart illustrating a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery according to another embodiment of the present invention.

Referring to FIG. 6 , (S10) the filtrate remaining after excluding the lithium carbonate in the result of the step (S4) of the present invention, and the lithium carbonate in the result of the step (S5) of the present invention and collecting the remaining washing liquid; (S20) concentrating the resultant of the step (S10) to increase the concentration of lithium ions in the resultant of the step (S10); (S30) adding sodium carbonate (Na ₂ CO ₃ ) to the resultant of step (S20) to form lithium carbonate (Li ₂ CO ₃ ); (S40) washing the lithium carbonate formed as a result of the step (S30) with distilled water; and (S50) drying the lithium carbonate formed as a result of the step (S40).

At this time, the filtrate or washing solution used in step (S10) may be a filtrate or a washing solution generated in a single lithium carbonate manufacturing process, and all of the filtrate or washing solution generated in two or more multiple lithium carbonate manufacturing processes It may be included, and when all of the filtrates or washing liquids generated in two or more of the plurality of lithium carbonate production processes are included, the effect of further increasing the recovery amount of Li occurs during lithium carbonate production.

Here, the (S20) step, the (S30) step, the (S40) step and the (S50) step are, respectively, the steps (S3), (S4), (S5) and (S6) of the present invention described above. ) may be performed in the same or similar manner as described in step, detailed description of each step is the same as described above.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are intended to illustrate the present invention, but the present invention is not limited by the following examples.

1. Preparation of filtrate (mother liquor) after Ni/Co/Mn recovery from waste cathode material

For the waste cathode material of the lithium secondary battery, Ni/Co/Mn was recovered through acid leaching and hydrolysis, and then a filtrate containing lithium was prepared as a mother solution.

Table 1 below shows the results of analysis using high-frequency inductively coupled plasma (ICP-MS) for the filtrate (mother liquor) after recovering the Ni/Co/Mn.

ingredient Li Ni Co Mn Mg Ca Zn Cu Fe Na Al Si content
(mg/kg) 2,552 23.6 3.2 1.5 2.6 2.9 N.D. N.D. N.D. 29,290 N.D. 3.5

2. Hydrolysis of mother liquid by adding sodium hydroxide (NaOH) to mother liquid

At room temperature, a 33% by weight aqueous sodium hydroxide solution was added to the prepared mother liquid, and the pH of the mother liquid was adjusted to 11.01. When the sodium hydroxide aqueous solution was added, stirring was performed together.

3. After hydrolysis, hydrochloric acid is added to the mother liquor (lithium chloride is formed) and concentrated (lithium ion concentration is increased).

After hydrolysis, 0.1, 0.3, 0.4, 0.5, and 0.7 moles of hydrochloric acid were added to 600 g of the mother liquid, respectively, and the maximum concentration of the mother liquid containing lithium was checked according to the number of moles of each hydrochloric acid. As a method to increase the concentration of the mother liquor (see Table 2 below), hydrochloric acid was added to change the form to lithium chloride, and a concentration test was performed. Table 2 below shows the solubility of each material in water according to temperature. Referring to Table 2 below, it can be confirmed that the solubility of lithium chloride (LiCl) is overwhelmingly higher than that of other materials.

Concentration was carried out using a vacuum evaporator, and during concentration, the vacuum degree was 140 mbar, the reaction temperature was 65 °C, and the stirring speed was fixed at 150 rpm. Concentration was terminated by determining that the time at which crystals were formed during vacuum evaporation concentration was the maximum concentration rate, and the lithium concentration and maximum concentration rate of the concentrate were shown in Table 3. As hydrochloric acid was added, the maximum concentration of the supernatant increased, but when 0.5 mol or more was added, the pH was lowered, and it was confirmed that the optimal hydrochloric acid input amount was about 0.4 mol. In addition, when the amount of hydrochloric acid input was 0.4 mol, the maximum concentration of the mother liquor was about 65.2%. As the concentration increased, the recovery rate of lithium carbonate increased.

temperature [℃] Li ₂ CO ₃ LiCl LiOH Na ₂ CO ₃ 0 1.54 68.3 12.7 7.0 10 - 74.5 - 12.2 20 1.32 83.2 - 21.8 25 1.27 84.5 12.9 29.4 30 - 85.9 - 39.7 40 - 89.4 13.0 48.8 50 1.01 - - 47.3 60 1.00 98.8 13.8 46.4 80 - 112.3 15.3 45.1 100 0.72 128.8 17.5 44.7

division weight
[g] Weight after concentration [g] maximum
concentration rate
[%] Li [before concentration] Li [after concentration] pH density
[mg/kg] Li total amount [g] density
[mg/kg] Li total amount [g] loss rate
[%] before reaction after reaction Supernatant after pH 11
(mother liquor) 600 600 0.0 2552 1.5312 2552 1.5312 0.0 11.01 - HCl
unadded 600 361.8 39.7 2552 1.5312 4185 1.5141 1.1 11.01 - HCl
0.1 mole 601.6 300.1 50.1 2552 1.5353 5079 1.5242 0.7 9.45 8.94 HCl
0.3 mole 608.4 240.5 60.5 2552 1.5526 6410 1.5416 0.7 6.87 8.06 HCl
0.4 mole 608.7 211.8 65.2 2552 1.5534 7284 1.5428 0.7 6.36 8.14 HCl
0.5 mole 603.1 180.4 70.1 2552 1.5391 8496 1.5327 0.4 2.38 1.12 HCl
0.7 mole 601.4 170.2 71.7 2552 1.5348 8975 1.5275 0.5 0.95 -0.18

4. Lithium carbonate synthesis and washing with sodium carbonate

To the concentrated mother liquid, 15 wt% of sodium carbonate (Na ₂ CO ₃ ) aqueous solution was added to a reaction tank to synthesize lithium carbonate.

Excess sodium ions coexist in the product after synthesizing lithium carbonate. Since sodium ions act as impurities in the product, in order to reduce the concentration of sodium ions, the product was washed with distilled water.

The content of distilled water used for washing was set to 5 to 30 times the weight of lithium carbonate. The reaction temperature during washing was carried out at 95 °C or higher in consideration of the solubility of lithium carbonate, the stirring speed was fixed at 150 rpm, and the lithium concentration and sodium concentration of lithium carbonate after washing with water are shown in Table 4 below.

division Li ₂ CO ₃ weight [g] Li concentration
[mg/kg] Li total amount
[g] recovery rate
[%] Na concentration
[mg/kg] concentrate 300 8651 2.5953 - non-taxation 9.682 181,000 1.7524 67.5 17,700 1:5 8.318 188,400 1.5671 60.4 1,580 1:7 7.972 188,500 1.5027 57.9 1,312 1:10 7.807 188,500 1.4716 56.7 1,027 1:15 7.616 183,000 1.3937 53.7 960 1:20 7.33 183,400 1.3443 51.8 915 1:25 7.218 183,500 1.3245 51.0 494 1:30 6.46 188,500 1.2177 46.9 474

When lithium carbonate was recovered without washing with water, the concentration of sodium was measured to be 17,700 mg/kg. In this case, there is a problem in using it as industrial lithium carbonate. Therefore, it is necessary to lower the concentration of sodium ions, and in this case, it can be confirmed that the water washing process using distilled water is effective. As the washing ratio increases, the concentration of sodium decreases, but the recovery rate of lithium also decreases (see FIG. 7 ). Therefore, it is necessary to select an ideal washing ratio during the washing process, and it can be seen that the most stable washing ratio is 1:10.

Thereafter, as an additional process, a finished lithium carbonate product may be produced through a drying step and/or a pulverization step.

5. Methods to further increase lithium carbonate recovery

In the case of recovering lithium carbonate from the mother liquor containing lithium, as a way to further increase the recovery rate of lithium, the recovery rate of lithium is when the filtrate and the washing solution are mixed and reused after two independent lithium carbonate production methods can be further increased. In the case of recovering only two lithium carbonate independent from each other from the mother liquor containing lithium, the recovery rate of lithium is 64.1 to 66.1%. The recovery rate increased to 82.7% (see Tables 5 to 8 below).

Table 5 below is a table showing the material flow of lithium ions according to the first manufacturing method of lithium carbonate, Table 6 below is a table showing the material flow of lithium ions according to the second method for manufacturing lithium carbonate, and Table 7 below is a table showing the material flow of lithium ions according to the second method for manufacturing lithium carbonate A table showing the recovery rate of lithium when lithium carbonate was synthesized by mixing the filtrate and washing liquid after the lithium carbonate manufacturing method of the gun (refer to the flow chart of the lithium carbonate manufacturing method in FIG. 6), and Table 8 is the first and second lithium carbonate This is a table showing the lithium recovery rate after the lithium ions recovered by the manufacturing method and the lithium ions recovered by synthesizing lithium carbonate after mixing the filtrate and washing solutions after the above two manufacturing methods are included.

division weight [g] Li concentration [mg/kg] Li total amount [g] Recovery rate [%] Li filtrate (mother liquor) 1980 2,557 5.0629 - After pH adjustment 1998 2,522 5.0390 99.5 After adding HCl 2003.7 2,510 5.0293 99.3 concentrate 688.3 7,164 4.9310 97.4 filtrate after synthesis 881.2 1,480 1.3042 25.8 wash amount 197.4 1,543 0.3046 6.0 Li ₂ CO ₃ 17.455 185,800 3.2431 64.1

division weight [g] Li concentration [mg/kg] Li total amount [g] Recovery rate [%] Li filtrate (mother liquor) 1980 2,557 5.0629 - After pH adjustment 1998 2,522 5.0390 99.5 After adding HCl 2003.3 2,510 5.0283 99.3 concentrate 725.1 6,747 4.8922 96.6 filtrate after synthesis 881.2 1,399 1.2328 24.3 wash amount 197.4 1,461 0.2884 5.7 Li ₂ CO ₃ 18.021 185,600 3.3447 66.1

division weight [g] Li concentration [mg/kg] Li total amount [g] Recovery rate [%] 1st, 2nd filtrate and washing solution mixture 2150 1505 3.2358 - concentrate 1174.8 2720 3.1955 98.8 filtrate after synthesis 1286.3 873 1.1229 34.7 wash amount 85.8 1574 0.1350 4.2 Li ₂ CO ₃ 9.308 185,100 1.7229 53.2

division weight [g] Li concentration [mg/kg] Li total amount [g] 1st and 2nd sum [g] Recovery rate [%] 1st undiluted solution 1980 2537 5.0233 10.05 82.7 2nd undiluted solution 1980 2537 5.0233 Primary Li ₂ CO ₃ 17.455 185800 3.2431 8.31 secondary Li ₂ CO ₃ 18.021 185600 3.3447 1st + 2nd reuse Li ₂ CO ₃ 9.308 185100 1.7229

When lithium carbonate is manufactured by the method according to the present invention, lithium carbonate (sodium concentration of 2,000 mg/kg or less) applicable to industry can be manufactured, and lithium ions can be recovered to 80% or more, so the recovery rate is high. It can be seen that it is very good.

The above description is merely illustrative of the present invention, and those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. will be able Therefore, the disclosed embodiments and experimental examples should be considered in an illustrative rather than a restrictive point of view. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (9)

(S1) hydrolyzing the mother liquid by adding sodium hydroxide (NaOH) to the mother liquid containing lithium;
(S2) adding hydrochloric acid (HCl) to the resultant of step (S1) to form lithium chloride (LiCl);
(S3) concentrating the resultant of step (S2) to increase the concentration of lithium ions in the resultant of step (S2);
(S4) adding sodium carbonate (Na ₂ CO ₃ ) to the resultant of step (S3) to form lithium carbonate (Li ₂ CO ₃ );
(S5) washing the lithium carbonate with water at 95° C. or higher with distilled water 5 to 25 times the weight of the lithium carbonate formed as a result of the step (S4);
(S6) drying the lithium carbonate formed as a result of the step (S5);
(S10) collecting the filtrate remaining after excluding the lithium carbonate from the resultant of step (S4) and the washing solution remaining after excluding the lithium carbonate from the resultant of step (S5);
(S20) concentrating the resultant of the step (S10) to increase the concentration of lithium ions in the resultant of the step (S10);
(S30) adding sodium carbonate (Na ₂ CO ₃ ) to the resultant of step (S20) to form lithium carbonate (Li ₂ CO ₃ );
(S40) washing the lithium carbonate with water at 95°C or higher with distilled water 5 to 25 times the weight of the lithium carbonate formed as a result of the step (S30); and
(S50) comprising the step of drying the lithium carbonate formed as a result of the step (S40),
Steps (S1) to (S6) are independently performed two cases,
The (S10) step is to collect the filtrate and the washing solution for both of the above two cases, a method for manufacturing lithium carbonate by recovering lithium from the waste electrode material of a lithium secondary battery. delete delete delete According to claim 1,
A method for manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery having a pH of 10.5 to 11.5 of the resultant after step (S1). According to claim 1,
The step (S3) is a method of manufacturing lithium carbonate by recovering lithium from a waste electrode material of a lithium secondary battery made through a vacuum evaporator. delete delete delete

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