Lithium recovery method

Abstract

The present invention relates to a lithium recovery method, and specifically, according to one embodiment of the present invention, a lithium recovery method can be provided comprising the steps of: preparing a lithium-containing solution containing lithium ions; when the lithium-containing solution passes through the chelating resin, exchanging the lithium ions with ions contained in the chelating resin, so that the lithium ions are bonded with the chelating resin; and enabling an acid solution to pass through the chelating resin bonded with the lithium ions, so that the lithium ions are separated from the chelating resin.

Description

Technical Field

[0001] The invention relates to a lithium recovery method. Background Art

[0002] Lithium (Li) is an essential industrial raw material used in various industries. Traditionally, lithium has been widely used in ceramics and chemical additives. In recent years, as the main industry has shifted to the wireless and power industries, lithium has been widely used in electronic devices such as mobile phones and laptops. In particular, as the demand for lithium batteries for electric vehicles (Battery Electric Vehicle, BEV) increases, it is necessary to develop a technology that can efficiently and economically extract lithium from lithium-containing resources.

[0003] Generally, lithium exists in nature in very small amounts in soil, rocks, and natural water. Therefore, it is necessary to recover lithium from soil, rocks, or natural water containing concentrated lithium, and to process the recovered lithium and use it in the form of a compound. For example, commercial lithium is concentrated in minerals or brine.

[0004] The method of recovering lithium from ore includes a variety of processes containing lithium raw materials, such as spodumene, lepidolite, amblygonite or petalite. In addition, the method of recovering lithium from ore includes a mining process, a crushing process, a separation process and a mineral processing process, followed by a heating process, a concentration process, a filtering process and an additive adding process for fine processing. Since the method of recovering lithium from ore requires multiple processes, equipment investment and operating costs increase and a large amount of acidic sludge is generated, causing serious environmental pollution.

[0005] On the other hand, in order to solve the problems arising from the method of recovering lithium from ore, a method of recovering lithium from brine present in a salt lake is being developed. In the conventional method of recovering lithium from brine, the brine is naturally evaporated to increase the lithium concentration in the brine to produce a compound in the form of lithium carbonate (Li2CO3), followed by precipitation of the lithium carbonate. However, the process of naturally evaporating the brine takes a long time (at least one year), and lithium is precipitated with other substances during the concentration process.

[0006] Therefore, there is a need for a lithium recovery method that can effectively recover lithium from a low-concentration lithium-containing solution in a short time. Summary of the invention

[0007] Technical issues

[0008] The present invention has been made under the above background, and an object of the present invention is to provide a technology capable of efficiently recovering lithium from a lithium-containing solution having a low lithium concentration.

[0009] In addition, an object of the present invention is to provide a technology capable of recovering lithium from a lithium-containing solution in a short time without requiring a long time for natural evaporation of the lithium-containing solution.

[0010] Another object of the present invention is to provide a technology capable of minimizing the amount of sludge generated and preventing environmental pollution.

[0011] Technical Solution

[0012] According to one embodiment of the present invention, a lithium recovery method can be provided, comprising the following steps: preparing a lithium-containing solution containing lithium ions; while the lithium-containing solution passes through a chelating resin, exchanging the lithium ions with ions contained in the chelating resin so that the lithium ions are bonded to the chelating resin; and allowing an acidic solution to pass through the chelating resin bonded to the lithium ions so that the lithium ions are separated from the chelating resin.

[0013] According to one embodiment of the present invention, a lithium recovery method can be provided, which also includes the step of mixing an alkaline solution into the lithium-containing solution to adjust the pH of the lithium-containing solution. While the pH of the lithium-containing solution is adjusted to a range of 10 to 13 by the alkaline solution, the lithium-containing solution can be passed through the chelating resin.

[0014] According to one embodiment of the present invention, a lithium recovery method may be provided, wherein the lithium-containing solution is provided such that the ratio of the amount of the lithium-containing solution passing through the chelating resin to the amount of the chelating resin is 4.17 to 8.33.

[0015] According to an embodiment of the present invention, a lithium recovery method may be provided, wherein the ratio of the amount of lithium ions bonded to the chelating resin to the amount of the chelating resin may be 1 to 1.3.

[0016] According to an embodiment of the present invention, a lithium recovery method may be provided, wherein the acidic solution is provided so that the ratio of the amount of the acidic solution passing through the chelating resin to the amount of the chelating resin is 1.5 to 2.5.

[0017] According to one embodiment of the present invention, a lithium recovery method can be provided, which also includes the step of allowing water to pass through a chelating resin bonded to lithium ions to separate the lithium ions from the chelating resin. The step of allowing water to pass through the chelating resin can be performed after the step of allowing an acidic solution to pass through the chelating resin.

[0018] According to one embodiment of the present invention, a lithium recovery method can be provided, which also includes the step of providing a phosphorus supply material containing one or more of phosphorus, phosphoric acid and phosphate to a purified lithium solution containing lithium ions separated from the chelating resin, and the lithium ion concentration in the lithium-containing solution can be 0.39 g / L or lower.

[0019] According to one embodiment of the present invention, a lithium recovery method may be provided, wherein the lithium-containing solution comprises seawater or brine having a sodium (Na) concentration of 30 g / L to 50 g / L.

[0020] According to one embodiment of the present invention, a lithium recovery method can be provided, wherein the ions contained in the chelating resin and exchanged with the lithium ions are hydrogen ions.

[0021] According to an embodiment of the present invention, the acid concentration in the acidic solution is 1.472 eq / L to 2.208 eq / L.

[0022] Effects of the Invention

[0023] According to the present invention, lithium can be effectively recovered from a lithium-containing solution having a low lithium concentration.

[0024] In addition, lithium can be recovered from the lithium-containing solution in a short time without naturally evaporating the lithium-containing solution for a long time.

[0025] Furthermore, the amount of sludge generated can be minimized and environmental pollution can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The flowchart sequentially shows the lithium recovery method according to one embodiment of the present invention.

[0027] Figure 2 is a graph showing the lithium binding capacity depending on pH.

[0028] Figure 3 is a graph showing the lithium binding capacity depending on the ratio of the sample amount to the chelating resin amount.

[0029] Figure 4 is a graph showing the hydrogen ion exchange rate depending on the ratio of the amount of the acidic solution to the chelating resin. DETAILED DESCRIPTION

[0030] The purpose of showing the embodiments of the present invention is to explain the technical spirit of the present invention. The scope of protection claimed in the present invention is not limited to the following embodiments or detailed descriptions of these embodiments.

[0031] Hereinafter, the present invention will be described with reference to the accompanying drawings.

[0032] Figure 1 The flowchart sequentially shows the lithium recovery method according to one embodiment of the present invention.

[0033] Reference Figure 1 In the lithium recovery method S1, lithium is recovered from a lithium-containing solution. For example, in the lithium recovery method S1, lithium can be recovered from seawater or brine in the form of lithium phosphate (Li3PO4).

[0034] Lithium recovery method S1 may include a step S100 of preparing a lithium-containing solution containing lithium ions. In this specification, the lithium-containing solution contains lithium ions. For example, the lithium ion concentration in the lithium-containing solution may be 0.39 g / L or lower. In addition, the lithium-containing solution may be seawater or salt water having a sodium (Na) concentration of 30 g / L to 50 g / L. In the step S100 of preparing the lithium-containing solution, the lithium-containing solution may be provided so that the ratio of the amount of the lithium-containing solution passing through the chelating resin to the amount of the chelating resin is 4.17 to 8.33. That is, the amount of the lithium-containing solution provided in the step S100 of preparing the lithium-containing solution may be 4.17 to 8.33 times (by volume ratio) the amount of the chelating resin.

[0035] Lithium recovery method S1 may include mixing alkaline solution in lithium-containing solution to adjust the step S200 of the pH of the lithium-containing solution. In this step S200 of mixing alkaline solution and lithium-containing solution, the alkaline solution is mixed with the lithium-containing solution, and the pH of the lithium-containing solution is adjusted to a range of 10 to 13. For example, the alkaline solution may be sodium oxide (NaOH). In addition, the step S200 of mixing alkaline solution and lithium-containing solution may be performed before the alkaline solution passes through a chelating resin. In this case, the lithium-containing solution may be passed through a chelating resin under the condition that the pH of the lithium-containing solution is adjusted to a range of 10 to 13 by an alkaline solution. As an example, the chelating resin used herein may be an ion exchange resin polymerized by adding divinylbenzene (DVB, Divinylbenzene) to polystyrene (Polystyrene).

[0036] Lithium recovery method S1 may include a step S300 of exchanging ions and lithium ions contained in the chelate resin while the lithium-containing solution passes through the chelate resin so that the lithium ions are bonded to the chelate resin. In the step S300 of exchanging ions and lithium ions contained in the chelate resin, the lithium-containing solution whose pH has been adjusted in the step S200 of mixing the alkaline solution and the lithium-containing solution passes through the chelate resin. When the lithium-containing solution passes through the chelate resin, the lithium ions contained in the lithium-containing solution are exchanged with the ions contained in the chelate resin. In other words, the lithium ions contained in the lithium-containing solution are bonded to the chelate resin, and the ions bonded to the chelate resin are separated from the chelate resin. In this case, the lithium ions contained in the lithium-containing solution are separated from the lithium-containing solution while being bonded to the chelate resin. For example, according to one embodiment of the present invention, the chelate resin may contain hydrogen ions, and the hydrogen ions may be exchanged with the lithium ions in the lithium-containing solution.

[0037] Lithium recovery method S1 may include a step S400 of passing an acidic solution through a chelating resin bonded to lithium ions to separate lithium ions from the chelating resin. In the step S400 of passing an acidic solution through the chelating resin, the acidic solution is passed through the chelating resin bonded to lithium ions, and when the acidic solution passes through the chelating resin, the lithium ions are separated from the chelating resin. The acid concentration in the acidic solution is 1.472eq / L to 2.208eq / L. For example, the acidic solution may be sulfuric acid (H2SO4) having a concentration of 72g / L or higher and 108g / L or lower. In addition, in the step S400 of passing an acidic solution through the chelating resin, an acidic solution may be provided so that the ratio of the amount of the acidic solution through the chelating resin to the amount of the chelating resin is 1.5 to 2.5. That is, the amount of the acidic solution provided in the step S400 of passing an acidic solution through the chelating resin may be 1.5 to 2.5 times (by volume) the amount of the chelating resin.

[0038] Lithium recovery method S1 may include a step S500 of passing water through a chelate resin bonded to lithium ions to separate lithium ions from the chelate resin. In the step S500 of passing water through the chelate resin, water is passed through the chelate resin bonded to lithium ions, and while water passes through the chelate resin, lithium ions are separated from the chelate resin. The step S500 of passing water through the chelate resin may be performed after the step S400 of passing an acidic solution through the chelate resin. In this case, when the acidic solution passes through the chelate resin, lithium ions are preliminarily separated from the chelate resin (step S400), and when water passes through the chelate resin, lithium ions are separated from the chelate resin again (step S500). In the step S500 of passing water through the chelate resin, water may be provided so that the ratio of the amount of water passing through the chelate resin to the amount of the resin is 1.5 to 2.5. That is, the amount of water provided in the step S500 of passing water through the chelate resin may be 1.5 to 2.5 times (by volume) the amount of the resin.

[0039] The lithium recovery method S1 may include providing a phosphorus supply material containing one or more of phosphorus, phosphoric acid and phosphate to a purified lithium solution S600. In this regard, the purified lithium solution is a solution containing lithium ions separated from a chelating resin. In the step S600 of providing the phosphorus supply material, the phosphorus supply material may react with the lithium ions to produce lithium phosphate (Li3PO4). In this regard, the phosphorus supply material includes one or more of phosphorus, phosphoric acid and phosphate, and the phosphate may be one or more of potassium phosphate, sodium phosphate and ammonium phosphate.

[0040] As such, the lithium recovery method S1 can recover lithium ions in the form of lithium phosphate from seawater or salt water containing lithium ions at a low concentration of 0.39 g / L or less.

[0041] Hereinafter, an embodiment of the lithium recovery method of the present invention will be described.

[0042] Analytical results based on pH

[0043] Table 1

[0044]

[0045] In the above Table 1, Examples 1 to 7 are experiments that only change the pH of the lithium-containing solution, but are performed under the same experimental conditions. Among them, pH adjustment is performed in step S200 of mixing the alkaline solution and the lithium-containing solution. In this specification, the lithium recovery rate (%) refers to the percentage of the amount of lithium bonded to the chelating resin relative to the amount of lithium contained in the lithium-containing solution before the reaction. In addition, the lithium bonding capacity refers to the amount of lithium bonded to the chelating resin relative to the amount of the chelating resin, and represents the degree of lithium recovery in the chelating resin. In other words, if it is assumed that the absolute amount (mg) of lithium in the processed sample is the same, the higher the lithium bonding capacity, the more lithium is recovered in the same chelating resin. As shown in Tables 1 and Figure 2 As shown, it can be seen that the lithium recovery rate and lithium bonding capacity will change with the change of pH value. In terms of lithium recovery rate and lithium bonding capacity, the lithium-containing solution with a pH adjusted to the range of 10 to 13 (Examples 4 to 6) is more preferred.

[0046] Analytical results based on the ratio of sample volume to chelating resin volume

[0047] Table 2

[0048]

[0049]

[0050] In the above table 2, embodiments 8 to 12 are experiments that change sample size but are performed under the same experimental conditions. In this specification, sample size refers to the amount of lithium-containing solution through the resin. In this respect, the experiment performed when the ratio of the amount of lithium-containing solution through the resin and the amount of the resin is presented in the table 2. Figure 3 As shown, it can be seen that the lithium bonding capacity changes with the change of the sample size relative to the amount of resin. In addition, it can be seen that when the ratio of sample size to the resin amount is 4.17 to 8.33, the lithium bonding capacity further improves (embodiments 9 to 11). If the ratio of the sample size in embodiment 9 to the resin amount is 4.17 or higher, the lithium bonding capacity has 1 or higher effective value. If the ratio of the sample size in embodiment 11 to the resin amount is 8.33 or lower, the lithium bonding capacity can be maintained at a predetermined level, and the addition of the sample can be prevented to be too much.

[0051] Analysis results based on the ratio of the amount of acid solution to the amount of chelating resin

[0052] Table 3

[0053]

[0054]

[0055] In the above table 3, embodiment 13 to 17 is to change the amount of solution, but the experiment of carrying out under the same experimental conditions.In this manual, the amount of solution refers to the amount of the acidic solution through the resin.In this respect, described table 3 is presented in the experiment of carrying out when changing the amount of the acidic solution through the resin and the ratio of the amount of the resin.As described table 3 and Figure 4 As shown, it can be seen that the hydrogen ion exchange rate can change with the change of the amount of the acidic solution consumed. It can be noted that when the ratio of the amount of solution to the amount of resin is 1.5 to 2.5 (by volume), the hydrogen ion exchange rate further improves (embodiments 15 to 17). If the ratio of the amount of solution as in embodiment 15 to the amount of resin is 1.5 or higher (by volume), then the hydrogen ion exchange rate increases significantly, and the amount of lithium recovered increases. In addition, if the ratio of the amount of solution as in embodiment 17 to the amount of resin is 2.5 or lower (by volume), then the addition of the acidic solution can be prevented from being too much. Although embodiments of the present invention have been described with reference to the accompanying drawings, those of ordinary skill in the field to which the present invention belongs will be able to appreciate that, without changing the technical spirit of the present invention or essential features, the present invention can be implemented in other specific forms.

[0056] Therefore, it should be understood that the embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the scope of the invention claims rather than the detailed description. It should be understood that all changes or modifications derived from the meaning and scope of the invention claims and their equivalent concepts are included in the scope of the present invention.

Claims

1. A lithium recovery method, characterized in that: The steps include: preparing a lithium-containing solution containing lithium ions; While the lithium-containing solution passes through the chelating resin, exchanging the lithium ions with the ions contained in the chelating resin so that the lithium ions are bonded to the chelating resin; and The acidic solution is passed through the chelate resin bonded to the lithium ions, so that the lithium ions are separated from the chelate resin.

2. The lithium recovery method according to claim 1, characterized in that: The method further comprises the step of mixing an alkaline solution into the lithium-containing solution to adjust the pH value of the lithium-containing solution. The lithium-containing solution is passed through the chelate resin in a state where the pH of the lithium-containing solution is adjusted to a range of 10 to 13 by the alkaline solution.

3. The lithium recovery method according to claim 1, characterized in that: The lithium-containing solution is provided so that a ratio of an amount of the lithium-containing solution passing through the chelating resin to an amount of the chelating resin is 4.17 to 8.

33.

4. The lithium recovery method according to claim 2 or 3, characterized in that: The ratio of the amount of lithium ions bonded to the chelate resin to the amount of the chelate resin is 1 to 1.

3.

5. The lithium recovery method according to claim 3, characterized in that: The acidic solution is provided so that the ratio of the amount of the acidic solution passing through the chelating resin to the amount of the chelating resin is 1.5 to 2.

5.

6. The lithium recovery method according to claim 1, characterized in that: The method further comprises the step of passing water through a chelating resin bonded to the lithium ions so as to separate the lithium ions from the chelating resin. The step of passing water through the chelating resin is performed after the step of passing the acidic solution through the chelating resin.

7. The lithium recovery method according to claim 1, characterized in that: The method further comprises providing a phosphorus supply material containing one or more of phosphorus, phosphoric acid and phosphate to the purified lithium solution containing lithium ions separated from the chelating resin. The lithium ion concentration in the lithium-containing solution is 0.39 g / L or less.

8. The lithium recovery method according to claim 7, characterized in that: The lithium-containing solution includes seawater or brine with a sodium concentration of 30 g / L to 50 g / L.

9. The lithium recovery method according to claim 1, characterized in that: The ions contained in the chelating resin and exchanged with the lithium ions are hydrogen ions.

10. The lithium recovery method according to claim 1, characterized in that: The acid concentration in the acidic solution is 1.472 eq / L to 2.208 eq / L.

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