Method for adsorption and desorption of lithium
By using aluminum-based adsorbents and multi-stage desorption steps, combined with the use of salt solutions of different concentrations, the problem of low lithium recovery efficiency was solved, achieving high-efficiency lithium recovery and concentration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- POSCO HLDG INC
- Filing Date
- 2024-12-12
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, lithium recovery efficiency is low, lithium hydroxide cannot be efficiently extracted from lithium-containing solutions, and the economics and lifespan of the adsorbent are problematic.
Aluminum-based adsorbents, such as aluminum hydroxide, are used to adsorb and desorb lithium through a multi-stage desorption process using salt solutions of different concentrations. The desorption process is optimized by combining distilled water and lithium salt solutions to improve lithium concentration and recovery rate.
This improved lithium recovery rate and concentration efficiency, reduced the load on subsequent concentration processes, and achieved a highly efficient lithium recovery process.
Smart Images
Figure CN122396785A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for the adsorption and desorption of lithium. Background Technology
[0002] Recently, with the rapid growth of the electric vehicle and related markets, the demand for lithium-ion batteries is increasing dramatically. Consequently, the demand for lithium hydroxide, one of the core raw materials for lithium-ion batteries, is also surging.
[0003] This type of lithium hydroxide is known to be produced by chemically converting lithium carbonate, which is produced in limited regions such as Chile or Argentina, with calcium hydroxide, etc., and it is known that it cannot be produced directly from raw materials.
[0004] Therefore, there is an urgent need to develop a technology that can economically and efficiently prepare lithium hydroxide from lithium-containing solutions.
[0005] As one such method, a technique for the selective adsorption and desorption of lithium using adsorbents is being investigated. Summary of the Invention
[0006] (a) Technical problems to be solved In the technology of recovering lithium by using lithium adsorption and desorption technology with adsorbents, a more efficient desorption technology is provided to provide a process that can efficiently recover lithium.
[0007] (II) Technical Solution In the following description, various embodiments of the present invention will be described in detail with reference to the accompanying drawings to facilitate implementation of the invention by those skilled in the art. The present invention can be implemented in various different ways and is not limited to the described embodiments.
[0008] For the sake of clear description of the invention, parts that are not relevant to the description have been omitted, and the same or similar reference numerals have been given to the same or similar constituent elements throughout the specification.
[0009] Furthermore, throughout the specification, when a part is described as "containing" a certain component, unless otherwise stated, it means that other components may also be included, and does not mean that other components are excluded.
[0010] The adsorption and desorption methods for lithium according to embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0011] First, the step of adsorbing lithium from the lithium-containing solution is performed.
[0012] Specifically, a lithium-containing solution is passed through an aluminum-based adsorbent so that lithium is adsorbed onto the aluminum-based adsorbent.
[0013] At this point, the lithium concentration of the lithium-containing solution can range from 0.04 g / L to 2.0 g / L, more specifically from 0.1 g / L to 1.0 g / L. If the lithium concentration of the lithium-containing solution is less than 0.1 g / L, the adsorption rate is slow, which may lead to reduced productivity. Furthermore, if the lithium concentration of the lithium-containing solution exceeds 2.0 g / L, although productivity increases, the adsorbent consumption increases, resulting in a relative decrease in economic efficiency. Therefore, the lithium concentration in the lithium-containing solution preferably meets the aforementioned range.
[0014] The aluminum-based adsorbent is used to adsorb lithium dissolved in the lithium-containing solution, and may contain, for example, aluminum hydroxide. As described in this embodiment, when using an aluminum-based adsorbent containing aluminum hydroxide, the adsorption capacity for lithium dissolved in the lithium-containing solution is high, and there is almost no aluminum loss in the desorption process described later. Therefore, the adsorbent has a long lifespan and offers the advantage of excellent economic efficiency in lithium extraction processes.
[0015] In addition, the aluminum-based adsorbent can be a molded body containing adsorbent powder and binder.
[0016] The adsorbent powder may be, for example, an adsorbent powder containing aluminum hydroxide. The advantages of using an adsorbent powder containing aluminum hydroxide are the same as those described above.
[0017] The binder is used to prepare the adsorbent powder into a molded body of suitable shape, thereby binding the adsorbent powder together. The binder may include, for example, at least one of polyvinyl chloride (PVC), polysulfone, and polyaniline. In particular, in this embodiment, the binder preferably includes polyvinyl chloride (PVC), which provides excellent bonding between the adsorbent powders.
[0018] On the other hand, the step of passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium onto the aluminum-based adsorbent may include, for example, a reaction comprising the following reaction formula 1.
[0019] [Reaction Formula 1] (1-x)LiCl·Al(OH)3·nH2O + Li + → LiCl·Al(OH)3·nH2O + (1-x)Li + Next, the step of obtaining a lithium-containing desorption solution is performed.
[0020] Specifically, a medium (e.g., distilled water or an aqueous solution containing lithium salt) can be passed through the aluminum adsorbent that has adsorbed lithium to obtain a lithium-containing desorbent.
[0021] At this point, based on the volume of the adsorbent, the amount of distilled water passing through the lithium-adsorbent aluminum adsorbent can be 0.5 to 100 times the volume of the adsorbent, more specifically 2 to 40 times.
[0022] When using distilled water less than 0.5 times the volume of the adsorbent to perform a desorption process on an aluminum-based adsorbent containing lithium, there is a problem of reduced desorption of lithium adsorbed on the adsorbent. Furthermore, when using distilled water more than 100 times the volume of the adsorbent, the desorbed lithium is diluted, resulting in a lower lithium concentration in the lithium-containing desorption solution.
[0023] The lithium concentration in the lithium-containing desorption solution obtained by the method described above can range from 0.2 g / L to 2.0 g / L, more specifically from 0.4 g / L to 1.0 g / L. When the lithium concentration in the lithium-containing desorption solution meets the above range, the recovery rate of lithium hydroxide obtained after performing the subsequent process described later is excellent.
[0024] The step of passing distilled water through the lithium-adsorbent aluminum adsorbent to obtain a lithium-containing desorbent may include, for example, a reaction comprising the following reaction formula 2.
[0025] [Reaction 2] LiCl·Al(OH)3·nH2O + H2O → (1-x)LiCl·Al(OH)3·nH2O + xLiCl + xAl(OH)3 For this lithium adsorption and desorption process, one embodiment of the present invention can provide a more specific desorption method.
[0026] One embodiment of the present invention provides a lithium adsorption and desorption method, comprising: an adsorption step in which a lithium-containing solution is passed through an aluminum-based adsorbent to obtain an adsorbent containing lithium; and a desorption step in which a medium is passed through the lithium-containing adsorbent to obtain a lithium-containing desorbed solution, wherein the medium used in the desorption step comprises a salt.
[0027] Thus, by using a medium containing lithium salts instead of simply using distilled water, the lithium concentration in the resulting desorbent can be increased. This improved lithium concentration in the desorbent can reduce the load on the subsequent concentration process.
[0028] Furthermore, in one embodiment of the present invention, a method for adsorbing and desorbing lithium is provided, comprising: an adsorption step in which a lithium-containing solution is passed through an aluminum-based adsorbent to obtain an adsorbent containing lithium; and a desorption step in which a medium is passed through the lithium-containing adsorbent to obtain a lithium-containing desorbed solution, wherein the desorption step is performed multiple times, the multiple desorption steps comprising a pre-desorption step and a post-desorption step, and the salt concentration in the medium used in the pre-desorption step and the post-desorption step is different.
[0029] Specifically, after the adsorption step, a multi-stage desorption process is performed using a medium. If the lithium concentration within the medium is varied within a certain range, the final lithium concentration of the desorbed solution may become higher.
[0030] A higher lithium concentration in the desorption solution means that less water needs to be removed in the subsequent concentration step, which can significantly reduce the load on the later stages of the process.
[0031] Specifically, the salt concentration in the medium of the preceding desorption step can be higher than the salt concentration in the medium of the subsequent desorption step. The reference salt in the salt concentration of the medium can be a lithium salt.
[0032] At this point, by comparing the lithium concentration of the front desorption solution obtained through the front desorption step with the lithium concentration of the rear desorption solution obtained through the rear desorption step, the number of front desorption steps can be determined.
[0033] As mentioned earlier, when obtaining the desorption solution, multiple desorption steps are performed. By comparing the lithium concentration in the desorption solution obtained in each step, the step ending at a predetermined point is defined as the previous desorption step, which can increase the lithium salt concentration in the medium at this point.
[0034] In other words, while a high-concentration medium is used up to the predetermined desorption step, a relatively low-concentration medium can be applied to the desorption step from a certain reference time point onwards.
[0035] At this point, when calculating the lithium concentration in the desorption solution, the lithium concentration contained in the medium can be excluded, and the amount of lithium desorbed by the adsorbent can be used as the benchmark.
[0036] This is because if a high-concentration medium is used in the desorption step, the lithium concentration in the resulting desorbate will be affected not only by the lithium desorbed from the adsorbent but also by the lithium concentration within the medium. In other words, this is to eliminate the influence of the medium and only consider the effects of adsorption and desorption.
[0037] Specifically, the initial desorption step can be maintained at a lithium concentration difference of more than 0.1 g / L between the initial and subsequent desorption solutions.
[0038] The medium may be an aqueous solution containing at least one of lithium chloride, lithium sulfate, and lithium borate.
[0039] The lithium concentration in the medium used in the first desorption step can be from 0.2 g / L to 0.4 g / L, and the lithium concentration in the medium used in the second desorption step can be from 0.1 g / L to 0.2 g / L.
[0040] It may also include a step of concentrating all the desorbed solution obtained through the pre-desorption step and the post-desorption step.
[0041] The concentration efficiency of the concentration step can be improved by more than 80%.
[0042] Concentration efficiency can be calculated as follows. Specifically, the efficiency of concentrating the final desorbed solution by the following two methods is compared: one is a method, as described in an embodiment of the present invention, in which the lithium salt concentration in the medium of the pre-desorption step and the post-desorption step is adjusted to be different; the other is a conventional method in which the lithium salt concentration in the medium of these steps is kept the same.
[0043] Specifically, the energy required for concentration when using the method of an embodiment of the present invention is the ratio of the energy required for concentration when the lithium salt concentration in the medium is kept the same.
[0044] When the desorption step is performed using the method of one embodiment of the present invention, the lithium concentration in the final desorption solution is high, and the amount of water that needs to be removed by concentration is significantly reduced, thereby enabling a highly efficient process design.
[0045] (III) Beneficial Effects In the technology of recovering lithium by using lithium adsorption and desorption technology with adsorbents, a more efficient desorption technology is provided to provide a process that can efficiently recover lithium. Attached Figure Description
[0046] Figure 1 These are lithium concentration data as a function of BV during the multi-stage desorption steps according to an embodiment and comparative example of the present invention.
[0047] Figure 2 The results are based on the analysis of actual lithium desorption amounts as a function of BV in the examples and comparative examples.
[0048] Figure 3 The results are based on the analysis of lithium concentration in the actual desorption solution as a function of BV in the examples and comparative examples. Detailed Implementation
[0049] The embodiments of the present invention are described in detail below. However, these are merely illustrative examples and the invention is not limited thereto; rather, it is defined solely by the scope of the claims.
[0050] Example A brine solution with the components shown in Table 1 was prepared.
[0051] Table 1 The adsorbent column is 100 ml, and the total desorption volume is approximately 3 L. Desorption is carried out in two stages: the first stage is ~6 BV (~0.6 L), and the second stage is 6~30 BV (0.6 L~3 L).
[0052] At this point, desorption was performed under the condition that the amount of medium used in one desorption step was defined as 1 bed volume (BV).
[0053] The initial desorption step is carried out up to 6 BV, and the subsequent desorption step is carried out from 7 BV up to 30 BV.
[0054] At this point, desorption was carried out under three different conditions.
[0055] The first condition is that desorption is carried out using distilled water in all steps.
[0056] The second condition is that desorption is carried out using an aqueous lithium chloride solution with a concentration of 0.15 g / L in all steps.
[0057] The third condition is that the concentration of lithium chloride in the medium used in the first desorption step is 0.3 g / L, and the concentration of lithium chloride in the medium used in the second desorption step is 0.15 g / L.
[0058] Figure 1 These are lithium concentration data as a function of BV during the multi-stage desorption steps according to an embodiment and comparative example of the present invention.
[0059] exist Figure 1 In the diagram, the dashed line represents data using distilled water for desorption, while the thick line represents data using a medium with the same lithium concentration throughout the desorption process.
[0060] Furthermore, the thin lines represent data from examples that perform multi-stage desorption steps. In this case, it can be confirmed that the lithium concentration is high across most of the BV range.
[0061] However, this can be attributed to the use of a high-concentration medium in the early stages, which, influenced by the lithium concentration within the medium, resulted in a higher lithium concentration in the desorption solution during most stages.
[0062] Figure 2 The results are based on the analysis of actual lithium desorption amounts as a function of BV in the examples and comparative examples.
[0063] at this time, Figure 2The data are calculated considering the lithium content in the medium; thus, it can be seen that in the initial BV stage, the amount of lithium desorbed from the adsorbent is actually less than that in the comparative example.
[0064] It is speculated that this is due to the influence of lithium in the medium, which may cause additional adsorption during the desorption process, and the lithium concentration in the medium has an inhibitory effect on desorption.
[0065] However, in Figure 2 One noteworthy finding is that if the final desorption step is carried out, the amount of lithium desorbed will eventually become the same.
[0066] Specifically, it can be confirmed that in the initial stage, the example with a lithium input concentration of 0.3 g / L and a output concentration of 0.57 g / L had a less desorption amount than the comparative example with an input concentration of 0.15 g / L and an output concentration of 0.47 g / L.
[0067] However, when desorption reaches approximately 30 BV, it can be confirmed that the total amount of effective desorption is almost the same. The results show that, within the range of approximately 18 BV, sufficient desorption of an equal amount of lithium can be expected.
[0068] This means that even if different media are used in the front and back sections as described in the examples, the fact that all lithium in the adsorbent is eventually desorbed remains unchanged.
[0069] Figure 3 The results are based on the analysis of lithium concentration in the actual desorption solution as a function of BV in the examples and comparative examples.
[0070] Figure 3 The result is also consistent with Figure 2 Similarly, this value takes into account the influence of lithium concentration within the medium.
[0071] like Figure 3 As shown, the lithium concentration in the desorption solution obtained in all desorption steps is confirmed to be high in the examples.
[0072] Specifically, observing 28.8 BV, the lithium concentration in the desorbent in the example was 244 mg / L, while the lithium concentration in the desorbent in the comparative example was 212 mg / L. This indicates that the effect of the example was improved by 87%.
[0073] This indicates that, in terms of the amount of water that needs to be removed when concentrating to the same concentration, the efficiency of the example is 87% higher than that of the comparative example.
[0074] In other words, the examples and comparative examples ultimately desorb the same amount of lithium, but the examples will obtain a desorbent solution with a higher concentration.
[0075] This invention is not limited to the embodiments described above, and can be prepared in various different ways. Those skilled in the art should understand that this invention can be implemented in other specific ways without changing the technical concept or essential features of the invention. Therefore, it should be understood that the above embodiments are exemplary in all respects and not restrictive.
Claims
1. A method for lithium adsorption and desorption, comprising: The adsorption step involves passing a lithium-containing solution through an aluminum-based adsorbent to obtain an adsorbent with adsorbed lithium; and The desorption step involves passing the medium through the adsorbent containing lithium to obtain a lithium-containing desorbed solution. The medium used in the desorption step contains salt.
2. The lithium adsorption and desorption method according to claim 1, wherein, The desorption step is performed multiple times. The multiple desorption steps include a pre-desorption step and a post-desorption step. The salt concentrations in the media used in the pre-desorption step and the post-desorption step are different.
3. The lithium adsorption and desorption method according to claim 2, wherein, The salt concentration in the medium of the preceding desorption step is higher than the salt concentration in the medium of the subsequent desorption step.
4. The lithium adsorption and desorption method according to claim 3, wherein, In the salt concentration within the medium, the reference salt is lithium salt.
5. The lithium adsorption and desorption method according to claim 3, wherein, The number of times the pre-desorption step is performed is determined by comparing the lithium concentration of the pre-desorption solution obtained through the pre-desorption step with the lithium concentration of the post-desorption solution obtained through the post-desorption step.
6. The lithium adsorption and desorption method according to claim 5, wherein, When calculating the lithium concentration in the desorption solution, the lithium concentration contained in the medium is excluded, and the amount of lithium desorbed by the adsorbent is used as the benchmark.
7. The lithium adsorption and desorption method according to claim 5, wherein, The first-stage desorption step is maintained until the lithium concentration difference between the first-stage desorption solution and the second-stage desorption solution is greater than 0.1 g / L.
8. The lithium adsorption and desorption method according to claim 2, wherein, The medium is an aqueous solution containing at least one of lithium chloride, lithium sulfate, and lithium borate.
9. The lithium adsorption and desorption method according to claim 2, wherein, The lithium concentration in the medium used in the first desorption step is 0.2 g / L to 0.4 g / L, and the lithium concentration in the medium used in the second desorption step is 0.1 g / L to 0.2 g / L.
10. The lithium adsorption and desorption method according to claim 2, further comprising: A step of concentrating all the desorbed solution obtained through the pre-desorption step and the post-desorption step.
11. The lithium adsorption and desorption method according to claim 10, wherein, The concentration step improves the concentration efficiency by more than 80%.