Process for separating zirconium and hafnium

Abstract

The application relates to the metallurgical technical field and discloses a method for extracting and separating zirconium and hafnium. Specifically, a sample containing zirconium and hafnium, an extractant and a diluent are subjected to extraction treatment to obtain upper liquid and lower liquid, and the upper liquid and the lower liquid are subjected to separation treatment so as to separate the zirconium and the hafnium. The method can effectively separate the zirconium and the hafnium, has the advantages of simple operation, recycling, low energy consumption and less harm to the environment, and is suitable for large-scale application.

Description

Technical Field

[0001] This application relates to the field of metallurgical technology, and more specifically, to a method for separating zirconium and hafnium. Background Technology

[0002] Zirconium (Zr) and hafnium (Hf) have very similar chemical properties, but they exhibit diametrically opposed nuclear characteristics. In nuclear-grade zirconium applications, hafnium is a harmful "neutron poison" that severely degrades reactor efficiency and economics. Zirconium and hafnium often coexist in nature in minerals such as zircon sand (ZrSiO4), with hafnium typically comprising 1.5% to 2.5% of zirconium.

[0003] Existing technologies for separating zirconium and hafnium still have many shortcomings. For example, the traditional pyrometallurgical zirconium-hafnium molten salt distillation method is complex, energy-intensive, and has limited separation efficiency; the fractional crystallization method has low separation efficiency and low overall yield; and the ion exchange method has disadvantages such as limited capacity, low production efficiency, and high cost. Solvent extraction is widely used in the production of nuclear-grade zirconium-hafnium due to its advantages of large production capacity, simple equipment, and ease of automation. However, extractants used in solvent extraction, such as methyl isobutyl ketone, have high toxicity and can easily cause environmental pollution. Other commonly used extractants, such as tributyl phosphate, are prone to emulsification during extraction, affecting the separation effect and posing certain environmental hazards.

[0004] Therefore, methods for separating zirconium and hafnium still need to be developed. Summary of the Invention

[0005] This application aims to address, to some extent, the problems existing in current separation technologies. To this end, this application proposes a method for separating zirconium and hafnium. This method can effectively separate zirconium and hafnium, and has the advantages of simple operation, recyclability, low energy consumption, and minimal environmental impact, making it suitable for large-scale application.

[0006] In one aspect of this application, a method for separating zirconium and hafnium is proposed. According to an embodiment of this application, the method includes: extracting a sample containing zirconium and hafnium, an extractant, and a diluent to obtain an upper layer and a lower layer; and separating the upper and lower layers to separate zirconium and hafnium; wherein the extractant comprises dibenzoylmethane, and the diluent comprises at least one of toluene and chloroform.

[0007] According to the method for separating zirconium and hafnium according to embodiments of this application, dibenzoylmethane (DBM) is used as the extractant. DBM forms different complexes with zirconium and hafnium. The inventors calculated parameters related to the stability of the complexes during the extraction process by studying their structure, stability, and other characteristics. Comparison revealed that the coordination process between DBM and zirconium is more stable, resulting in a higher partition ratio of zirconium extraction during the extraction process. Therefore, the upper layer containing zirconium and the lower layer containing hafnium can be separated by this method. Furthermore, since dibenzoylmethane is a solid, it needs to be dissolved in a diluent beforehand. The inventors found that different diluents have significant differences in their solubility of DBM and their effect on the separation of zirconium and hafnium. For example, kerosene or n-octanol cannot effectively dissolve DBM as a diluent, while dichloromethane, although able to dissolve DBM well, has poor extraction effect on zirconium that forms coordination compounds with DBM, thus resulting in ineffective separation of hafnium and zirconium. Through in-depth research, the inventors discovered that toluene or chloroform, as diluents, can quickly and fully dissolve DBM. In particular, there is a π-π stacking effect of benzene rings between toluene and the coordination extract, which makes the coordination extract more stable and also improves the solubility of the extract, thus effectively extracting zirconium. Meanwhile, the distribution of hafnium in the DBM and diluent system is relatively low, thereby achieving effective separation of zirconium and hafnium.

[0008] According to embodiments of this application, the above-described method for separating zirconium and hafnium may also have the following additional technical features: According to embodiments of this application, the sample to be processed includes zirconium salt, hafnium salt, and an acidity regulator. By adding the acidity regulator, an acidic environment is provided for the extraction process, controlling the hydrogen ion concentration to inhibit the hydrolysis of metal ions. The high concentration of anion of the acidity regulator promotes the extraction and separation of the coordination extract, and the anion will form a mixed coordination extract with zirconium and DBM, thereby improving the extraction and separation effect of zirconium in the DBM and diluent system.

[0009] According to embodiments of this application, the concentration of zirconium in the sample to be treated is 1 ppm to 10,000 ppm. In some embodiments, the concentration of hafnium in the sample to be treated is 1 ppm, 10 ppm, 100 ppm, 1000 ppm, 2500 ppm, 5000 ppm, 7500 ppm, or 10,000 ppm, preferably 10 ppm to 1000 ppm. When the concentration of zirconium in the sample to be treated meets the above conditions, the separation effect of zirconium and hafnium can be effectively improved.

[0010] According to embodiments of this application, the concentration of hafnium in the sample to be treated is 1 ppm to 20,000 ppm. In some embodiments, the concentration of hafnium in the sample to be treated is 1 ppm, 10 ppm, 20 ppm, 100 ppm, 1000 ppm, 2000 ppm, 5000 ppm, 10000 ppm, 15000 ppm, or 20000 ppm, preferably 20 ppm to 2000 ppm. When the hafnium concentration in the sample to be treated meets the above conditions, the separation effect of hafnium and zirconium can be effectively improved.

[0011] According to embodiments of this application, the concentration of the acidity regulator in the sample to be treated is 0.01 mol / L to 1 mol / L. In some embodiments, the concentration of the acidity regulator in the sample to be treated is 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, or 1 mol / L, preferably 0.4 mol / L to 0.6 mol / L. The concentration of the acidity regulator in the sample to be treated, satisfying the above conditions, can provide a suitable acidic environment for the system, control the hydrogen ion concentration to inhibit the hydrolysis of metal ions, and simultaneously, the anion of the acidity regulator will promote the formation of coordination complexes and mixed coordination complexes, which is beneficial to the effective separation of zirconium and hafnium.

[0012] According to an embodiment of this application, the zirconium salt in the sample to be treated includes at least one of zirconium tetrachloride, zirconium oxychloride, and zirconium oxynitrate. According to embodiments of this application, the hafnium salt in the sample to be treated includes at least one of hafnium tetrachloride, hafnium oxychloride, and hafnium oxide.

[0013] According to embodiments of this application, the acidity regulator in the sample to be treated includes at least one of hydrochloric acid, nitric acid, and perchloric acid.

[0014] According to an embodiment of this application, before performing the extraction process, the extractant is dissolved in a diluent to obtain a mixture. Since dibenzoylmethane is a solid, it is dissolved in a diluent beforehand to facilitate effective extraction later.

[0015] According to embodiments of this application, the concentration of dibenzoylmethane in the mixture is 10 mmol / L to 1000 mmol / L. In some embodiments, the concentration of dibenzoylmethane in the mixture is 10 mmol / L, 20 mmol / L, 50 mmol / L, 100 mmol / L, 200 mmol / L, 300 mmol / L, 400 mmol / L, 500 mmol / L, 750 mmol / L, or 1000 mmol / L, preferably 100 mmol / L to 300 mmol / L. The concentration of dibenzoylmethane in the mixture meeting the above conditions can effectively improve the separation effect of zirconium and hafnium.

[0016] According to an embodiment of this application, the volume ratio of the mixture to the sample to be treated is (1~3):1. This facilitates the complete dissolution of zirconium in the sample, improving the separation effect.

[0017] According to embodiments of this application, the extraction temperature is 25°C to 35°C. This improves the selectivity of the extractant for zirconium in the sample, thereby enhancing the separation effect.

[0018] According to embodiments of this application, the extraction treatment time is 0.5 h to 12 h. In some embodiments, the extraction treatment time is 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 5 h, 8 h, or 12 h, preferably 2.5 h to 3.5 h.

[0019] According to an embodiment of this application, the extraction process is carried out under stirring conditions at a stirring speed of 200 rpm to 300 rpm. This ensures that zirconium is fully dissolved in the extractant and diluent system, thereby improving the separation effect.

[0020] According to an embodiment of this application, the separation process includes centrifugation at a speed of 2000 rpm to 4000 rpm for 3 min to 10 min. Thus, centrifugation can disrupt the emulsion layer and achieve rapid and thorough separation of the upper and lower liquid layers, facilitating the effective separation of zirconium and hafnium.

[0021] Beneficial effects: The extraction and separation method for zirconium and hafnium disclosed in this application can effectively separate the two materials. Regarding separation efficiency, this method significantly improves the separation coefficient of zirconium and hafnium, achieving more efficient separation and meeting the stringent requirements of high-end industries for high-purity zirconium and hafnium products. In terms of environmental friendliness, the extraction agent used in this method, dibenzoylmethane, has low toxicity and minimal environmental impact. The diluent, toluene, is recyclable, reducing the emission of organic solvents into the environment and lowering pollution levels, aligning with the principles of green chemistry. Regarding cost control, this method reduces energy consumption and raw material waste during production, and its recyclability lowers the production costs of the extractant and diluent, enhancing the economic benefits and competitiveness of large-scale applications. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 It represents the distribution ratio of zirconium and hafnium under different hydrochloric acid concentrations; Figure 2 The distribution ratio of zirconium and hafnium under different dibenzylmethane concentrations; Figure 3 It represents the distribution ratio of zirconium and hafnium under different oscillation time conditions. Detailed Implementation

[0023] The present application will be explained below with reference to embodiments and comparative examples. Those skilled in the art will understand that the following embodiments and comparative examples are for illustrative purposes only and should not be construed as limiting the scope of the application. Where specific techniques or conditions are not specified in the embodiments and comparative examples, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Unless otherwise stated, the active pharmaceutical ingredients, excipients, and reagents used in the following embodiments and comparative examples are commercially available products or can be prepared by known methods.

[0024] Before introducing the technical solution of this application, the relevant knowledge of this application will be introduced below: In the embodiments of this application, "extraction processing" can be simply referred to as extraction, also known as solvent extraction or liquid-liquid extraction. It is a separation and purification technology based on the difference in solubility of solute in two immiscible (or slightly soluble) solvents. The core is to selectively transfer the target substance from one liquid phase (original system) to another liquid phase (extraction phase) by selecting a suitable extraction solvent, and finally achieve the separation, concentration or purification of the target substance and impurities.

[0025] In the embodiments of this application, "upper layer liquid and lower layer liquid" refer to two independent liquid phases formed after two immiscible (or slightly soluble) liquids are mixed and shaken during the extraction process, and then allowed to stand and separate. The separation is primarily determined by the density difference between the two extraction solvents and is a direct product of the extraction separation. The lower layer liquid is the denser liquid phase, which settles to the bottom of the mixed system due to gravity after standing. In the embodiments of this application, the lower layer liquid refers to the aqueous phase containing hafnium. The upper layer liquid is the less dense liquid phase, floating on top of the mixed system. In the embodiments of this application, the upper layer liquid refers to the organic phase containing zirconium, extractant, and diluent.

[0026] In the embodiments of this application, "partition ratio" refers to a parameter that measures the distribution behavior of a target substance between two phases during extraction treatment. Specifically, it is the ratio of the total concentration of the target substance in the extraction phase (including free state and various bound state) to the total concentration in the raffinate phase (including free state and various bound state) when extraction equilibrium is reached. The larger the partition ratio, the more soluble the target substance is in the extraction phase, and the higher its extraction efficiency.

[0027] In the embodiments of this application, "π-π stacking of benzene rings" refers to a weak intermolecular force formed by the superposition of electrostatic attraction and dispersion between the π electron clouds of benzene rings of two compounds containing benzene rings. It is a special form of van der Waals force. In the embodiments of this application, the π-π stacking of diluent toluene and dibenzoylmethane can stabilize and improve the solubility of the extract.

[0028] In the embodiments of this application, "hydrolysis of metal ions" refers to a type of acid-base reaction between metal ions and water molecules in aqueous solution. This involves metal ions abstracting hydroxyl groups from water molecules through polarization, releasing hydrogen ions, and forming products such as hydroxides and hydroxyl complexes, while simultaneously making the solution acidic. During the extraction process, the hydrolysis of metal ions generates hydroxide precipitates or hydroxyl complexes. These products are difficult to form coordination complexes with the extractant, resulting in a decrease in extraction efficiency.

[0029] In the embodiments of this application, "coordination complex" refers to a stable complex-type extract formed by the metal ions, which are the main target substances, and the extractant (including chelating agents, organophosphorus compounds, amines, etc.) through coordination bonds during the extraction process. It is a carrier for achieving phase transfer and separation and purification of the target substances.

[0030] In the embodiments of this application, "mixed coordination extract" refers to a complex-type extract in which the metal ion, as the main target substance, is simultaneously bound to two or more different types of ligands through coordination bonds during the extraction process. This results in a structurally stable complex-type extract with multiple ligand properties. In the embodiments of this application, mixed coordination extract refers to a complex-type extract formed by the coordination of the target metal ion with the extractant dibenzoylmethane and the diluent toluene.

[0031] In the embodiments of this application, "emulsion layer" refers to a turbid, viscous, and unstable intermediate phase formed between the upper and lower liquid layers during the extraction process, where the stability of the system is disrupted and two immiscible liquid phases (such as organic and aqueous phases) cannot separate normally.

[0032] In the embodiments of this application, the "separation coefficient" refers to an index used to measure the separation effect between the target substance and impurities in the extraction process. Specifically, when the extraction equilibrium is reached, the separation coefficient is equal to the ratio of the distribution ratio of the two substances.

[0033] In the embodiments of this application, "ICP-MS" refers to inductively coupled plasma mass spectrometry, which is a trace / ultra-trace element analysis technique that combines the high-temperature ionization characteristics of inductively coupled plasma (ICP) with the high-sensitivity detection characteristics of mass spectrometry (MS). It is used for the qualitative, quantitative and isotopic analysis of metal ions and non-metal elements in samples.

[0034] In the embodiments of this application, "extraction rate" refers to a parameter that quantifies the separation and extraction effect of the target substance in the extraction process. Specifically, it is the percentage of the total amount of the target substance transferred to the extraction phase after extraction equilibrium compared with the total amount of the target substance in the initial system.

[0035] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Example 1 In this embodiment, zirconium and hafnium are separated according to the following method: 1. Accurately weigh appropriate amounts of zirconium tetrachloride and hafnium tetrachloride, and slowly add them to hydrochloric acid solution. Stir in a magnetic stirrer at a constant temperature of 25°C until completely dissolved to obtain the sample to be treated. The concentration of zirconium in the sample to be treated is 10 ppm, the concentration of hafnium is 20 ppm, and the concentration of hydrochloric acid is 0.5 mol / L.

[0037] 2. Dissolve dibenzoylmethane in toluene to prepare a mixed solution with a dibenzoylmethane (DBM) concentration of 200 mmol / L.

[0038] 3. Take 3.0 mL of the mixture and 3.0 mL of the sample to be treated and place them in a 10 mL plastic centrifuge tube. Place the centrifuge tube in a constant temperature shaker and extract and shake at 250 rpm for 3 h at 25℃.

[0039] 4. After extraction, place the centrifuge tubes in a benchtop high-speed centrifuge and centrifuge at 3000 rpm for 3 minutes. After centrifugation, the liquid in the tubes will separate into clear upper and lower layers.

[0040] 5. Carefully aspirate the lower layer sample using a syringe, dilute it with 0.5 mol / L hydrochloric acid, and then determine the accurate concentrations of zirconium and hafnium using ICP-MS.

[0041] Examples 2-13 Zirconium and hafnium were separated according to the method in Example 1, except that the hydrochloric acid concentration was replaced with 0.01 mol / L, 0.4 mol / L, 0.6 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, and 5 mol / L, respectively.

[0042] The results are attached. Figure 1 As shown, D represents the partition ratio of zirconium or hafnium. With the hydrochloric acid concentration increasing from 0.01 mol / L to 5 mol / L, the partition ratios of both zirconium and hafnium showed a significant trend of first increasing and then decreasing. Under hydrochloric acid concentrations of 0.01 mol / L to 0.4 mol / L, zirconium and hafnium ion hydrolysis was excessive, resulting in a lower partition ratio. Under hydrochloric acid concentrations of 0.6 mol / L to 5 mol / L, extraction was inhibited, and the extractant showed poor extraction efficiency for zirconium. Samples treated with hydrochloric acid concentrations of 0.4 mol / L to 0.6 mol / L achieved better extraction rates and separation coefficients, realizing effective separation. Among these, a hydrochloric acid concentration of 0.5 mol / L showed the best results.

[0043] Examples 14-18 Zirconium and hafnium were separated according to the method in Example 1, except that the concentration of DBM in the mixture was replaced with 50 mmol / L, 75 mmol / L, 100 mmol / L, 150 mmol / L, and 300 mmol / L, respectively.

[0044] The results are attached. Figure 2As shown in the logarithmic coordinate graph of log(D) versus log([DBM]), two straight lines with slopes close to 4 are obtained, where D represents the partition ratio of zirconium or hafnium. This slope corresponds to the coordination ratio in the extraction reaction, verifying that during extraction, one metal ion (zirconium or hafnium) combines with approximately four DBM molecules to form a stable coordination complex (i.e., a stoichiometric ratio of approximately 1:4), indicating that extraction is based on a stable coordination chemical reaction. The results show that the partition ratios of both zirconium and hafnium increase continuously with increasing DBM concentration, while the ratio of zirconium to hafnium partition ratios (i.e., the separation coefficient) does not change significantly with increasing dibenzoylmethane concentration. Considering both extraction efficiency and reagent cost, a dibenzoylmethane concentration of 100 mmol / L to 300 mmol / L can achieve good separation results. A dibenzoylmethane concentration of 200 mmol / L shows the best effect.

[0045] Examples 19-30 Zirconium and hafnium were separated according to the method of Example 1, except that the extraction oscillation time was replaced with 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 8, 10, and 12 hours, respectively.

[0046] The results are attached. Figure 3 As shown, D represents the zirconium or hafnium partition ratio. The results show that the zirconium-hafnium partition ratio increases rapidly at first and then gradually decreases with increasing extraction oscillation time. Between 2.5 h and 3.5 h, the partition ratio tends to its maximum value, and the separation coefficient remains basically constant. Considering both extraction rate and time cost, an extraction oscillation time of 3 h yields the best results.

[0047] Comparative Example 1 Zirconium and hafnium were separated according to the method of Example 1, except that the diluent toluene was replaced with kerosene.

[0048] The dissolving effect of the obtained diluent is shown in Table 1: Table 1:

[0049] The results are shown in Table 1: During the preparation process, DBM showed low solubility in kerosene (the known saturation solubility is approximately 50 mmol / L), failing to reach the 200 mmol / L concentration required in Example 1. Most of the DBM precipitated at the bottom as a white solid, failing to form a homogeneous organic phase solution. Due to the ineffective dissolution of the extractant, subsequent liquid-liquid extraction contact and stratification operations were impossible, resulting in the inability to perform extraction separation and thus obtain effective data on the partition ratio of zirconium and hafnium.

[0050] Comparative Example 2 Zirconium and hafnium were separated according to the method of Example 1, except that the diluent toluene was replaced with dichloromethane.

[0051] The dissolution effect of the obtained diluent is shown in Table 2: Table 2:

[0052] The results are shown in Table 2. Although dichloromethane can dissolve DBM well, serious problems arise during the extraction process: severe solvent evaporation. Due to the low boiling point of dichloromethane (approximately 39.6℃), the solvent evaporates extremely quickly during isothermal shaking and centrifugation at 25℃, resulting in a significant reduction in the volume of the organic phase and an uncontrollable change in the two-phase ratio (O / A), making it impossible to maintain the designed volume ratio. After settling and centrifugation, the system fails to form a clear two-phase (upper and lower liquid) interface, instead forming a distinct third phase between the aqueous and organic phases. This indicates insufficient solubility of the extract in dichloromethane or unstable interfacial properties, causing metal ions to remain at the interface and fail to effectively enter the organic phase, thus preventing the acquisition of effective extraction partition parameters. This demonstrates that the method of using dichloromethane as a diluent to dissolve the extractant is ineffective for the extraction and separation of zirconium and hafnium.

[0053] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0055] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for separating zirconium and hafnium, characterized in that, include: The sample containing zirconium and hafnium, along with the extractant and diluent, were extracted to obtain the upper and lower layers. The upper and lower liquid layers are separated to separate the zirconium and hafnium. The extractant includes dibenzoylmethane, and the diluent includes at least one of toluene and chloroform.

2. The method according to claim 1, characterized in that, The samples to be processed include zirconium salts, hafnium salts, and acidity regulators.

3. The method according to claim 2, characterized in that, The concentration of zirconium in the sample to be treated is 1 ppm to 10,000 ppm.

4. The method according to claim 2, characterized in that, The concentration of zirconium in the sample to be treated is 10 ppm to 1000 ppm.

5. The method according to claim 2, characterized in that, The concentration of hafnium in the sample to be treated is 1 ppm to 20,000 ppm.

6. The method according to claim 2, characterized in that, The concentration of hafnium in the sample to be treated is 20 ppm to 2000 ppm.

7. The method according to claim 2, characterized in that, The concentration of the acidity regulator in the sample to be treated is 0.01 mol / L to 1 mol / L.

8. The method according to claim 2, characterized in that, The concentration of the acidity regulator in the sample to be treated is 0.4 mol / L to 0.6 mol / L.

9. The method according to any one of claims 2, 3 or 4, characterized in that, The zirconium salt includes at least one of zirconium tetrachloride, zirconium oxychloride, and zirconium oxynitrate.

10. The method according to any one of claims 2, 5 or 6, characterized in that, The hafnium salt includes at least one of hafnium tetrachloride, hafnium oxychloride, and hafnium oxide.

11. The method according to any one of claims 2, 7 or 8, characterized in that, The acidity regulator includes at least one of hydrochloric acid, nitric acid, and perchloric acid.

12. The method according to claim 1, characterized in that, Before performing the extraction process, the extractant is dissolved in a diluent to obtain a mixture.

13. The method according to claim 12, characterized in that, The concentration of dibenzoylmethane in the mixture is 10 mmol / L to 1000 mmol / L.

14. The method according to claim 12, characterized in that, The concentration of dibenzoylmethane in the mixture is 100 mmol / L to 300 mmol / L.

15. The method according to claim 12, characterized in that, The volume ratio of the mixture to the sample to be treated is (1~3):

1.

16. The method according to claim 1, characterized in that, The extraction process is carried out at a temperature of 25℃~35℃.

17. The method according to claim 1, characterized in that, The extraction process takes 0.5 h to 12 h.

18. The method according to claim 1, characterized in that, The extraction process takes 2.5 h to 3.5 h.

19. The method according to claim 1, characterized in that, The extraction process was carried out under stirring conditions, with a stirring speed of 200 rpm to 300 rpm.

20. The method according to claim 1, characterized in that, The separation process includes centrifugation, with a centrifugation speed of 2000 rpm to 4000 rpm and a time of 3 min to 10 min.

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