Method for preparing lithium carbonate
By controlling the precipitation rate and employing centrifugation and washing, the method effectively reduces impurities in lithium carbonate production, achieving high-purity lithium carbonate with reduced costs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- POSCO HLDG INC
- Filing Date
- 2025-10-29
- Publication Date
- 2026-06-11
AI Technical Summary
Existing methods for producing lithium carbonate are inefficient in reducing impurities and require multiple impurity removal processes, leading to high auxiliary raw material costs.
A method involving controlled precipitation of lithium carbonate by adjusting the introduction rate of lithium-ion-containing brine into a carbonate source, followed by centrifugation and washing, to minimize impurity capture and reduce the number of subsequent purification steps.
This approach results in high-purity lithium carbonate with reduced impurity levels, specifically sulfur and boron at 0.01 wt% and 0.003 wt% respectively, and a purity of 99.2 wt%, thereby minimizing auxiliary raw material usage and production costs.
Smart Images
Figure KR2025017391_11062026_PF_FP_ABST
Abstract
Description
Method for manufacturing lithium carbonate
[0001] The present invention relates to a method for manufacturing lithium carbonate.
[0002] Lithium carbonate produced from brine is purified by removing impurities. In particular, high-purity lithium carbonate is required for use as an electrode or electrolyte in lithium-ion batteries. To obtain high-purity lithium carbonate, it undergoes multiple impurity removal processes.
[0003] The objective of the present invention is to provide a method for producing high-purity lithium carbonate that can reduce the number of subsequent impurity removal processes by lowering impurities in the lithium carbonate extraction process step.
[0004] The objective of the present invention is to provide a method for producing high-purity lithium carbonate that can reduce the amount of auxiliary raw materials used for removing impurities.
[0005] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.
[0006] In one embodiment of the present invention, a method for producing lithium carbonate is provided, comprising the step of introducing a lithium ion-containing brine into a carbonate source to precipitate lithium carbonate.
[0007] The precipitation rate of lithium carbonate particles can be controlled by adjusting the rate at which the above lithium-ion-containing brine is introduced.
[0008] The above lithium-ion-containing brine can be injected at a rate of 0.15 ml / second to 1.11 ml / second.
[0009] The total amount of the lithium-ion-containing brine added may be greater than the equivalent amount of lithium ions contained in the lithium-ion-containing brine and carbonate ions among the carbonate ion sources that form lithium carbonate.
[0010] The method for manufacturing the above lithium carbonate further includes the step of concentrating the lithium ion-containing brine, and the lithium ion-containing brine may be the concentrated lithium ion-containing brine.
[0011] The above method for manufacturing lithium carbonate may further include the step of obtaining precipitated lithium carbonate by centrifuging it.
[0012] The method for manufacturing the lithium carbonate described above may further include a step of washing the precipitated lithium carbonate.
[0013] The above method for manufacturing lithium carbonate is to obtain the result of centrifuging the precipitated lithium carbonate, and the sulfur content included as an impurity in the result may be 0.01 wt% or less based on the solid content of the result.
[0014] The above method for manufacturing lithium carbonate is obtained by centrifuging the precipitated lithium carbonate, and the boron content included as an impurity in the above product may be 0.003 wt% or less based on the solid content of the above product.
[0015] The method for manufacturing the lithium carbonate above is to obtain the result of centrifuging the precipitated lithium carbonate, and the purity of the lithium carbonate may be 99.2 wt% or higher based on the solid content of the result.
[0016] The above carbonate ion source may be a Na2CO3 solution.
[0017]
[0018] In one embodiment of the present invention, solid lithium carbonate obtained according to the method for producing lithium carbonate is provided.
[0019] The above-mentioned solid lithium carbonate may include lithium carbonate in the form of needle-shaped particles.
[0020] The above-mentioned solid lithium carbonate may have a purity of 99.2 wt% or higher.
[0021] According to the above method for manufacturing lithium carbonate, the number of subsequent impurity removal processes can be reduced by lowering impurities in the lithium carbonate extraction process step, and the amount of auxiliary raw materials used for impurity removal can be reduced, thereby reducing auxiliary raw material costs and enabling the production of high-purity lithium carbonate without increasing process costs.
[0022] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below.
[0023] Figure 1 schematically illustrates a process diagram of the method for manufacturing the above lithium carbonate.
[0024] Figures 2 to 5 are graphs showing the results of measuring the content of S, B, K, and Na, respectively, in the lithium carbonate cake according to the reaction time.
[0025] Figure 6 is a graph showing the results of measuring the purity of lithium carbonate according to reaction time.
[0026] Figures 7 to 10 are graphs showing the results of measuring the content of S, B, K, and Na in lithium carbonate cakes prepared with different washing cycles.
[0027] Figure 11 is a graph showing the results of measuring the purity of lithium carbonate cakes prepared with different washing cycles.
[0028] Figures 12 to 15 are graphs showing the results of measuring the content of S, B, K, and Na in lithium carbonate cakes prepared with different washing times according to the number of washing cycles.
[0029] Figure 16 is a graph showing the results of measuring the purity of lithium carbonate cakes prepared with different washing times according to the number of washes.
[0030] Figures 17 and 18 are graphs showing the particle size distribution of lithium carbonate cakes prepared by different manufacturing methods.
[0031] Figures 19 and 20 are graphs showing the particle size measurement results of lithium carbonate cakes prepared by different manufacturing methods.
[0032] Figure 21 is an SEM image of lithium carbonate particles prepared by different manufacturing methods.
[0033] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.
[0034] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.
[0035] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.
[0036] In one embodiment of the present invention, a method for producing lithium carbonate is provided, comprising the step of introducing a lithium ion-containing brine into a carbonate ion source to precipitate lithium carbonate.
[0037] According to the above method for manufacturing lithium carbonate, the number of subsequent impurity removal processes can be reduced by lowering impurities in the lithium carbonate extraction process step, and the amount of auxiliary raw materials used for impurity removal can be reduced, thereby reducing auxiliary raw material costs and enabling the production of high-purity lithium carbonate without increasing process costs.
[0038] Figure 1 schematically illustrates a process diagram of the method for manufacturing the above lithium carbonate.
[0039] The above method for manufacturing lithium carbonate involves introducing the lithium ion-containing brine (2) into a reaction vessel (10) containing the carbonate source (1), in contrast to the method of introducing a carbonate ion source into a reaction vessel containing brine. The brine (2) can be introduced at a predetermined speed by a pump.
[0040] The above method for manufacturing lithium carbonate can reduce the impurity content by controlling the precipitation rate of lithium carbonate particles by adjusting the rate at which the lithium ion-containing brine (2) is introduced, thereby reducing the capture of impurities within the particles during the precipitation of lithium carbonate particles. Specifically, the precipitation rate of lithium carbonate particles can be controlled so that the extraction time during the precipitation of lithium carbonate increases.
[0041] In one embodiment, the lithium-ion-containing brine (2) can be introduced at a rate of 0.15 ml / second to 1.11 ml / second, specifically 0.20 ml / second to 1.11 ml / second. By introducing the lithium-ion-containing brine (2) at a rate within the above numerical range, the impurities of lithium carbonate obtained by precipitation can be reduced.
[0042] The total amount of the lithium-ion-containing brine (2) can be such that the lithium ions contained in the lithium-ion-containing brine (2) and the carbonate ions contained in the carbonate source (1) form an equivalent amount of lithium carbonate.
[0043] In one embodiment, the carbonate ion source may be a Na2CO3 solution.
[0044] The above method for manufacturing lithium carbonate can be performed in a batch type or a continuous type. FIG. 1 is an example of a batch type, but in the case of a continuous type, the lithium ion-containing brine (2) can be continuously introduced into the reaction vessel (10), and the precipitation rate of lithium carbonate particles can be controlled by adjusting the introduction ratio with the carbonate source (1). When the above method for manufacturing lithium carbonate is performed as a continuous reaction, the introduction ratio of the carbonate source (1) and the lithium ion-containing brine (2) can be determined according to the relative introduction rate of the lithium ion-containing brine (2) with respect to the carbonate source (1).
[0045] In one embodiment, when the method for producing lithium carbonate is carried out as a continuous reaction, the relative input rate of the lithium ion-containing brine (2) to the carbonate source (1) can be adjusted to be the input rate of the lithium ion-containing brine (2) in the aforementioned batch type. In one embodiment, when the method for producing lithium carbonate is carried out as a continuous reaction, the relative rate of the lithium ion-containing brine (2) to the carbonate source (1) can be 0.15 ml / second to 1.11 ml / second, specifically 0.20 ml / second to 1.11 ml / second. The relative input rate of the lithium ion-containing brine (2) to the carbonate source (1) can be calculated as the value obtained by subtracting the input rate of the carbonate source (1) from the input rate of the lithium ion-containing brine (2).
[0046] The method for manufacturing the lithium carbonate described above may further include a step of concentrating the lithium-ion-containing brine (2). The concentrated lithium-ion-containing brine can be used as the lithium-ion-containing brine (2). For example, the brine can be concentrated using an evaporation pond.
[0047] Before introducing the concentrated lithium-ion-containing brine into the reaction vessel (10), a step of removing impurities may be further included. The impurities may be elements or ions such as Mg, Ca, B, etc. The method of removing such impurities from the concentrated lithium-ion-containing brine may be by a known method. The concentrated lithium-ion-containing brine from which impurities have been removed as above may be used as the lithium-ion-containing brine (2).
[0048] The above method for manufacturing lithium carbonate may further include the step of obtaining precipitated lithium carbonate by centrifuging it.
[0049] After taking the slurry containing the lithium carbonate precipitated from the above reaction vessel (10), centrifuge it with a centrifuge (20), and filter the extraction filtrate (extraction filtrate / washing filtrate when performing the washing step described later) (5) to obtain a solid lithium carbonate cake (4). The lithium carbonate cake obtained in this way can be washed with water to further remove impurities and increase its purity.
[0050] The method for manufacturing the lithium carbonate described above may further include a step of washing the precipitated lithium carbonate. The washing water (3) may be water and can remove impurities that are easily washed away by water.
[0051] For example, the washing step described above can be performed repeatedly. For example, the lithium carbonate cake can be washed by soaking it in water for more than 4 hours.
[0052] As described above, the method for manufacturing the lithium carbonate can reduce the impurity content by reducing the capture of impurities within the particles during precipitation, and the types of impurities to be reduced may be impurities such as S, B, etc., which are elements that are not effectively removed by washing in the washing step.
[0053] In the lithium carbonate cake obtained by the above method for manufacturing lithium carbonate, impurities such as Na and K, which are easily washed away in the washing step, are removed, thereby allowing the total impurity of the solid lithium carbonate finally obtained after washing to be reduced.
[0054] In a method for producing lithium carbonate according to one embodiment, the precipitated lithium carbonate is obtained as a centrifugal product, and the sulfur content included as an impurity in the product may be 0.01 wt% or less based on the solid content of the product.
[0055] In a method for producing lithium carbonate according to one embodiment, the precipitated lithium carbonate is obtained as a centrifugal product, and the boron content included as an impurity in the product may be 0.003 wt% or less based on the solid content of the product.
[0056] The solid lithium carbonate obtained according to the above method for manufacturing lithium carbonate may be suitable for battery grades requiring high purity.
[0057] In a method for producing the lithium carbonate according to one embodiment, the precipitated lithium carbonate is obtained as a centrifugal result, and the purity of the lithium carbonate may be 99.2 wt% or higher based on the solid content of the result.
[0058]
[0059] In one embodiment of the present invention, solid lithium carbonate obtained according to the method for producing lithium carbonate is provided.
[0060] A detailed description of the solid lithium carbonate obtained above is as previously stated.
[0061] The above lithium carbonate may include lithium carbonate in the form of needle-shaped particles. It is understood that the shape of the needle-shaped particles reduces the capture of impurities during the generation and growth stages of primary particles, and can enhance the effect of washing away impurities during the washing stage.
[0062] In one embodiment, the solid lithium carbonate may have a purity of 98.0 wt% or more.
[0063] In one embodiment, the solid lithium carbonate may have a sulfur content of 0.01 wt% or less as an impurity.
[0064] In one embodiment, the solid lithium carbonate may have a boron content of 0.003 wt% or less as an impurity.
[0065]
[0066] Examples and comparative examples of the present invention are described below. The following examples are merely embodiments of the present invention, and the present invention is not limited to the following examples.
[0067]
[0068] (Example)
[0069] Example 1
[0070] A lithium-ion-containing brine at 85°C was introduced into a 5L reaction vessel containing a 25% concentration Na2CO3 solution (85°C, 1.0 eq.) using a metering pump at a flow rate of 0.20 ml / sec. The precipitated lithium carbonate slurry was transferred and centrifuged and filtered to obtain a lithium carbonate cake, and the obtained lithium carbonate cake was washed with 85°C washing water to obtain the final lithium carbonate powder.
[0071] Comparative Example 1
[0072] A 25% Na2CO3 solution (85°C, 1.0 eq.) was introduced into a 5L reaction vessel containing 4L of lithium-ion-containing brine (85°C) using a metering pump at a flow rate of 0.56 ml / sec. The precipitated lithium carbonate slurry was transferred and centrifuged and filtered to obtain a lithium carbonate cake, and the obtained lithium carbonate cake was washed with 85°C washing water to obtain the final lithium carbonate powder.
[0073]
[0074] Experimental Example
[0075] (1) Evaluation based on reaction time
[0076] For the lithium carbonate cakes obtained in Example 1 and Comparative Example 1, the content of impurities S, B, K, and Na (elements or ions) and the purity of lithium carbonate were measured before and after washing (measuring instrument: ICP-OES).
[0077] FIGS. 2 to 5 are graphs showing the results of measuring the content of S, B, K, and Na, respectively, in the lithium carbonate cakes obtained in Example 1 and Comparative Example 1 according to reaction time.
[0078] Figure 6 is a graph showing the results of measuring the purity of lithium carbonate obtained in Example 1 and Comparative Example 1 according to reaction time.
[0079]
[0080] Looking at the results before washing, the concentrations of S and B impurities were relatively high in Comparative Example 1 and the concentrations of Na and K were high in Example 1, so the overall purity of lithium carbonate was similar, but after washing, the removal rate of Na and K in Example 1 was relatively very high and the concentrations of S and B were low, so the purity of lithium carbonate was higher compared to Comparative Example 1.
[0081]
[0082] (2) Evaluation based on the number of washes
[0083] The impurity concentration and lithium carbonate purity of the lithium carbonate cake obtained in Example 1 and Comparative Example 1 were evaluated while increasing the number of washes.
[0084] FIGS. 7 to 10 are graphs showing the results of measuring the content of S, B, K, and Na in the lithium carbonate cake obtained in Example 1 and Comparative Example 1 according to the number of washes.
[0085] Figure 11 is a graph showing the results of measuring the purity of the lithium carbonate cake obtained in Example 1 and Comparative Example 1 according to the number of washes.
[0086] In FIGS. 7 to 10, for both Example 1 and Comparative Example 1, the impurity concentration decreased up to the second washing cycle, and the purity of lithium carbonate increased, but thereafter, there was no significant change in purity. In the case of Example 1, it was confirmed that high purity of 99.0% was achieved after the third wash. Although the Na and K content of Example 1 was actually higher than that of Comparative Example 1 at the beginning of the washing cycle, the content was significantly lowered after the first wash, and after the second wash, it was confirmed that the content was lower than that of Comparative Example 1.
[0087]
[0088] (3) Evaluation based on washing time
[0089] A lithium carbonate cake obtained by the same method as in Example 1 was compared with different washing times. The case where the washing time was 2 hours was designated as Example 1-1, and the case where it was 4 hours was designated as Example 1-2, and for each of Examples 1-1 and 1-2, the number of washing cycles was increased for evaluation.
[0090] FIGS. 12 to 15 are graphs showing the results of measuring the content of S, B, K, and Na in the lithium carbonate cake obtained in Examples 1-1 and 1-2 according to the number of washes.
[0091] FIG. 16 is a graph showing the results of measuring the purity of the lithium carbonate cake obtained in Examples 1-1 and 1-2 according to the number of washes (values exceeding 100% are due to measurement error).
[0092] When washing the lithium carbonate cake according to the number of washes, the impurity washing efficiency during the initial washing was relatively higher in the case of Example 1-2 compared to the case of Example 1-1. At 3 washes or fewer, the impurity concentration is affected by the moisture content of the lithium carbonate cake obtained by centrifugation / filtration. Therefore, when looking at the values for 4 washes or more, the purity of lithium carbonate was higher in the case of Example 1-2 than in Example 1-1 from the 4th wash onwards.
[0093]
[0094] (4) Evaluation of particle size distribution
[0095] Lithium carbonate cakes obtained by the same method as in Example 1 and Comparative Example 1 were prepared by washing times of 20, 40, 60, 80, and 100 minutes, respectively, and the cumulative volume 10% particle size D 10 Eul, volume accumulation 50% particle size D 50 and volume accumulation 90% particle size D 90 was measured (measuring instrument: Malvern particle size analyzer).
[0096] FIG. 17 is a graph showing the particle size distribution of the lithium carbonate cake obtained in Example 1, and FIG. 18 is a graph showing the particle size distribution of the lithium carbonate cake obtained in Comparative Example 1.
[0097] FIG. 19 is a graph showing the particle size measurement results of the lithium carbonate cake obtained in Example 1, and FIG. 20 is a graph showing the particle size measurement results of the lithium carbonate cake obtained in Comparative Example 1.
[0098] Example 1 exhibited a wider range of particle size distribution compared to Comparative Example 1. In the case of Example 1, it was confirmed that the D10 particle size was relatively smaller, while the D50 and D90 particle sizes tended to be larger. It is understood that this particle size distribution influences the result of obtaining lithium carbonate with lower impurities and higher purity in Example 1 compared to Comparative Example 1.
[0099]
[0100] In addition, lithium carbonate cakes were obtained by washing for 20 minutes, 40 minutes, 60 minutes, and 120 minutes, respectively, in the same manner as in Example 1 and Comparative Example 1. FIG. 21 is an SEM image of lithium carbonate particles obtained by the method of Example 1 and Comparative Example 1.
[0101] In FIG. 21, the primary particles of lithium carbonate prepared by the method of Comparative Example 1 exhibit a plate-like shape, while the primary particles of lithium carbonate prepared by the method of Example 1 exhibit a needle-like shape. Although these needle-like primary particles are formed to be relatively small, the secondary particles formed by the aggregation of the primary particles tend to be larger in size. It is understood that the lithium carbonate prepared by the method of Example 1 is formed with relatively small primary particles, thereby reducing the capture of impurities. Meanwhile, it is understood that the impurity removal effect during the washing step is superior due to the shape of the needle-like primary particles.
[0102]
[0103] Although the present invention has been described above with reference to embodiments, the present invention is not limited by the embodiments disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.
[0104]
[0105] [Explanation of the symbol]
[0106] 1: Carbonate ion source
[0107] 2: Brine
[0108] 3: Washing water
[0109] 4: Lithium Carbonate Cake
[0110] 5: Extraction filtrate / Wash filtrate
[0111] 10: Reactor
[0112] 20: Centrifuge
[0113] 30: Pump
Claims
1. A method for producing lithium carbonate comprising the step of precipitating lithium carbonate by introducing a lithium ion-containing brine into a carbonate source.
2. In Paragraph 1, Controlling the precipitation rate of lithium carbonate particles by controlling the rate at which the above lithium-ion-containing brine is introduced. Method for manufacturing lithium carbonate.
3. In Paragraph 2, The above lithium-ion-containing brine is injected at a rate of 0.15 ml / sec to 1.11 ml / sec. Method for manufacturing lithium carbonate.
4. In Paragraph 1, The total amount of the lithium-ion-containing brine added is greater than or equal to the amount of lithium ions contained in the lithium-ion-containing brine and the equivalent amount of carbonate ions among the carbonate ion sources that form lithium carbonate. Method for manufacturing lithium carbonate.
5. In Paragraph 1, The method further includes a step of concentrating the lithium-ion-containing brine, wherein the lithium-ion-containing brine is a concentrated lithium-ion-containing brine. Method for manufacturing lithium carbonate.
6. In Paragraph 1, A method further comprising the step of obtaining precipitated lithium carbonate by centrifugation. Method for manufacturing lithium carbonate.
7. In Paragraph 1, A further step of washing the precipitated lithium carbonate Method for manufacturing lithium carbonate.
8. In Paragraph 1, The precipitated lithium carbonate is obtained as a centrifugal product, and the sulfur content included as an impurity in the product is 0.01 wt% or less based on the solid content of the product. Method for manufacturing lithium carbonate.
9. In Paragraph 1, The precipitated lithium carbonate is obtained as a centrifugal product, and the boron content included as an impurity in the product is 0.003 wt% or less based on the solid content of the product. Method for manufacturing lithium carbonate.
10. In Paragraph 1, The precipitated lithium carbonate is obtained as a centrifugal product, and the purity of the lithium carbonate is 99.2 wt% or higher based on the solid content of the product. Method for manufacturing lithium carbonate.
11. In Paragraph 1, The above carbonate ion source is a Na2CO3 solution Method for manufacturing lithium carbonate.
12. Solid lithium carbonate obtained according to the method for manufacturing lithium carbonate of claim 1.
13. In Paragraph 12, The above lithium carbonate includes lithium carbonate in the form of needle-shaped particles. High-quality lithium carbonate.
14. In Paragraph 12, The above-mentioned solid lithium carbonate has a lithium carbonate purity of 99.2 wt% or higher. High-quality lithium carbonate.