A rapid lithium element separation system and method driven by vacuum negative pressure

Abstract

The present invention provides a rapid lithium element separation system and method driven by vacuum negative pressure. The system includes a chromatographic microcolumn, a beaker or a sample dissolution tank, a vacuum pump and a vacuum device; the chromatographic microcolumn is filled with a cation exchange resin, and both the upper and lower ends thereof are sealed with PE sieve plates; the beaker or the sample dissolution tank is located inside the vacuum device; the lower end outlet of the chromatographic microcolumn is connected to the beaker or the sample dissolution tank through an outlet pipeline via a pipeline valve and through the top cover of the vacuum device; an opening is provided on the side of the vacuum device and is connected to the vacuum pump through a vacuum pipeline; the beaker or the sample dissolution tank is used for receiving the waste liquid or the lithium-containing solution flowing out of the chromatographic microcolumn. The system and method provided by the present invention realize the rapid separation of Li element in geological samples through vacuum negative pressure drive and in combination with the chromatographic microcolumn method for ultra-clean laboratories.

Description

Technical Field

[0001] The present invention relates to a rapid lithium element separation system and method driven by vacuum negative pressure, belonging to the technical field of chemical analysis. Background Art

[0002] The Li element separation technology is necessary for the analysis and testing of the Li isotope composition of geological samples by multi-channel inductively coupled plasma mass spectrometry (MC-ICPMS). Liquid chromatography technology is often used to separate and purify elements or macromolecules, and the separation of Li element is no exception. In liquid chromatography technology, strong acidic cation exchange resins are usually used to fill chromatographic micro-columns, and the separation of Li element is achieved manually. However, this method has always been complex in operation, difficult to control column efficiency, and low in working efficiency. At the same time, due to economic benefits and other reasons, the instruments for preparative chromatography are concentrated in the fields of biology, medicine, sugar making, etc. The separation of inorganic elements such as Li is relatively niche and difficult to have great economic value. However, for the global isotope geology analysis field, the Li isotope analysis has an urgent and huge market demand. Therefore, the problem of Li element separation needs to be solved urgently.

[0003] In the 1990s of the last century, with the rise of multi-channel inductively coupled plasma mass spectrometers, the analysis and research of non-traditional stable isotopes have been greatly developed. The non-traditional stable isotopes include Li, B, Mg, Si, Fe, Cu, Zn, etc. Since then, the analysis of Li isotope composition has gradually got rid of the bondage of traditional mass spectrometry technologies (such as ICP-MS, TIMS) and become a new academic research hotspot. However, geological samples are complex and changeable, and there are still some technical bottlenecks in their chemical pretreatment, especially the separation technology of Li element needs to be developed urgently.

[0004] Li usually appears as a trace element in geological samples, while Na, K, Mg, Ca, etc. are major elements. The content of Na is generally several thousand times to tens of thousands of times that of Li. In order to improve the analysis accuracy, the MC-ICPMS instrument analysis needs to remove the interference of elements such as Na, K, Mg, Ca, etc. Strong acidic cation exchange resins (such as AG50 X12, AG50X8, AG MP 50, etc.) are widely used for the separation of Li element. During the separation process, reagents such as HCl, HNO 3 etc. are used for elution. According to the different binding strengths of different ions to the resin, elements such as Li, Na, K, Mg, Ca, etc. are separated in turn (as shown in Figure 1 shown, such as Figure 1 shown, at room temperature, strong acid elution, the cation order is Li + 、Na + 、NH 4 + 、K + 、Mg 2+ 、Ca 2+etc.). However, there are too many impurities and too complex types in geological samples, and the distribution coefficient differences between Li and Na are not very large, so it is not easy to completely separate them. At the same time, the requirement for Li recovery rate is too strict and it must be completely recovered because the Li isotope fractionation effect is very strong during the separation process by cation exchange resin. These are all objective difficulties faced by the Li element separation experiment.

[0005] Half a century ago, Flesch et al. began to determine the isotope composition of Li standard samples by mass spectrometry in 1973; Strelow et al. achieved the separation of Li element using cation exchange resin (AG50W-X8) in 1974. In the following decades, the Li isotope separation technology has been constantly innovating and progressing. The main improvements in the Li isotope separation technology include: (a) improving the resin, including developing resins with different cross-linking degrees, using smaller and more uniform resin particle sizes, improving macroporous resins, etc.; (b) trying different types and concentrations of acids, including 0.2 - 1.5 mol / L HCl, HNO 3 etc.; (c) adding organic solvents such as methanol, ethanol, acetone, etc.; (d) repeating the separation process, such as 2 - 4 times of micro-column separation.

[0006] A large number of studies have shown that using 3 - 6 mL of resin and a micro-column length of more than 10 cm, the one-time column separation of Li element can be applicable to most geological samples. However, according to the capillary flow velocity formula, the flow velocity of the micro-column reagent is proportional to the second to fifth power of the micro-column length, that is, as the micro-column lengthens, the flow velocity rapidly slows down. Many laboratory research results show that it is very difficult to complete the experiment within one day (8 hours). Usually, the height of the resin material filled in the manual chromatographic micro-column is less than 5 cm, even less than 1 cm, so the separation operation can be completed relatively simply and quickly; there are many practical operation difficulties with chromatographic micro-columns of more than 10 cm. Compared with modern high-pressure chromatography technology, using a chromatographic column with a diameter of 1 - 6 mm and a length of 5 - 40 cm, it needs to be driven by a high-pressure plunger pump (15 - 60 MPa) and most of the analysis and tests can be completed within 5 minutes to half an hour. In order to achieve effective separation of Li isotopes in a super-clean laboratory, a chromatographic micro-column with sufficient length is required, resulting in problems such as too slow flow velocity and uneven flow velocity. Therefore, the Li element separation process in geological laboratories requires a convenient, practical and effective driving technology to increase the flow velocity and improve the column efficiency.

[0007] Therefore, providing a rapid separation system and method for lithium element driven by vacuum negative pressure has become an urgent technical problem to be solved in this field. Summary of the Invention

[0008] In order to solve the above-mentioned drawbacks and deficiencies, an object of the present invention is to provide a rapid separation system for lithium element driven by vacuum negative pressure.

[0009] Another object of the present invention is to provide a method for rapid separation of lithium element driven by vacuum negative pressure. The system and method provided by the present invention achieve rapid separation of Li element in geological samples through vacuum negative pressure drive and combined with chromatographic microcolumn method for ultra-clean laboratory.

[0010] To achieve the above object, on the one hand, the present invention provides a system for rapid separation of lithium element driven by vacuum negative pressure. Among them, the system for rapid separation of lithium element driven by vacuum negative pressure includes: a chromatographic microcolumn, a beaker or a sample dissolution tank, a vacuum pump and a vacuum device; the chromatographic microcolumn is filled with cation exchange resin, and both its upper and lower ends are sealed with PE sieve plates; the beaker or the sample dissolution tank is located inside the vacuum device; the lower end outlet of the chromatographic microcolumn is connected to the beaker or the sample dissolution tank through an outlet pipeline via a pipeline valve and through the top cover of the vacuum device; an opening is provided on the side of the vacuum device and is connected to the vacuum pump through a vacuum pipeline;

[0011] The beaker or the sample dissolution tank is used to receive the waste liquid or the lithium-containing solution flowing out of the chromatographic microcolumn.

[0012] As a specific embodiment of the above system of the present invention, the vacuum device is a sealed box made of transparent polycarbonate. The sealed box has a detachable top cover. An opening is provided on the top cover, and a Luer connector is fixedly connected to the opening. The outlet pipeline is connected to the vacuum device through the Luer connector.

[0013] Among them, the Luer connector fixedly connected to the opening of the top cover of the sealed box facilitates the insertion and removal of the connected pipeline and also facilitates the connection of the connected pipeline to the chromatographic microcolumn.

[0014] As a specific embodiment of the above system of the present invention, the Luer connector is fixedly connected to the opening through a sealant.

[0015] As a specific embodiment of the above system of the present invention, the material of the sample dissolution tank is Teflon or polypropylene.

[0016] As a specific embodiment of the above system of the present invention, the length of the chromatographic microcolumn is 10 - 40 cm.

[0017] As a specific embodiment of the above system of the present invention, the chromatographic microcolumn is filled with 3 - 6 mL of AG50W-X12 resin, and the mesh number of the resin is 200 - 400.

[0018] As a specific embodiment of the above system of the present invention, the PE sieve plate is a 20 μm PE sieve plate.

[0019] In the present invention, the upper end of the chromatographic microcolumn is also sealed with a PE sieve plate, which can prevent the resin from floating when adding samples and reagents, and can also prevent the resin from scattering during operation and storage.

[0020] When using the system provided by the present invention, it is necessary to pay attention to the tightness of the vacuum device and check whether the pressure meets the experimental requirements. When the chromatographic microcolumn is not in use, it can be stored in hydrochloric acid with a concentration of about 0.1N to avoid contamination and damage such as mold and deterioration of the resin; the connecting pipelines and pipeline valves need to be soaked in concentrated hydrochloric acid, cleaned with deionized water, dried at 90°C, and then stored in a sealed bag to prevent contamination; the Teflon sample dissolution tank can be soaked and cleaned with aqua regia or reverse aqua regia.

[0021] On the other hand, the present invention also provides a method for rapid separation of lithium element driven by vacuum negative pressure. In this method, the above-mentioned vacuum negative pressure driven lithium element rapid separation system is used, which includes:

[0022] (1) Wash the cation exchange resin in the chromatographic microcolumn with concentrated acid reagent and deionized water respectively;

[0023] (2) Add acid solution to the chromatographic microcolumn with a pipette to balance the acidity environment of the cation exchange resin, and the acid solution used to balance the acidity environment of the cation exchange resin is the same as the acid solution used to dissolve the target geological sample;

[0024] (3) Dissolve the target geological sample in the acid solution, suck the target geological sample solution with a pipette and add it to the chromatographic microcolumn, and then add acid solution to the chromatographic microcolumn;

[0025] (4) Elute the cation exchange resin with an eluent; in steps (1)-(4), waste liquid is collected in a beaker;

[0026] (5) Continue to elute the cation exchange resin with an eluent and collect the lithium-containing solution with a sample dissolution tank. Among them, the washing process in step (1) and the elution processes in steps (4) and (5) require a negative pressure driving force provided by a vacuum pump, that is, the vacuum pump is in an open state in steps (1), (4), and (5); while the balancing process in step (2) and the sample loading process in step (3) do not require a negative pressure driving force provided by a vacuum pump, that is, the vacuum pump is in a closed state in steps (2) and (3).

[0027] In the method described above of the present invention, the concentrated acid reagent used in step (1), the acid solution used in step (3), and the acid substances of the eluent (acid solution) described in steps (4) and (5) may be the same or different; in addition, the concentrated acid reagent used in step (1), the acid solution used in step (3), and the eluent (acid solution) described in steps (4) and (5) may be the same as or different from the acid solution used to dissolve the target geological sample. Those skilled in the art can determine the specific substances of the acid solutions used in these steps according to the actual situation of the chromatographic column, etc.

[0028] As a specific embodiment of the method described above of the present invention, the eluent includes one or a combination of several of nitric acid, hydrochloric acid, tartaric acid, and citric acid.

[0029] As a specific embodiment of the method described above of the present invention, an organic solvent is further added to the eluent. Adding an organic solvent to the eluent can obtain different elution curves and elution orders. In addition, heating can also change the ion distribution coefficient when strongly acidic cation exchange resin separates cations.

[0030] Among them, the present invention does not make specific requirements on the addition amount of the organic solvent. Those skilled in the art can reasonably set the addition amount of the organic solvent according to the actual on-site situation, as long as the purpose of the present invention can be achieved.

[0031] As a specific embodiment of the method described above of the present invention, the organic solvent includes one or a combination of several of methanol, ethanol, and acetone.

[0032] As a specific embodiment of the method described above of the present invention, the flow rates of the concentrated acid reagent and deionized water in step (1), the eluent in step (4), and the eluent in step (5) are all adjustable in the range of 0.1 - 10 mL / minute.

[0033] As a specific embodiment of the method described above of the present invention, the concentrated acid reagent in step (1) is concentrated hydrochloric acid, the acid solutions in steps (2) and (3) are both hydrochloric acid, and the eluents used in steps (4) and (5) are both hydrochloric acid.

[0034] In step (3) of the method of the present invention, adding an acid solution to the chromatographic microcolumn can wash off the Li attached to the wall of the chromatographic microcolumn to ensure the experimental recovery rate.

[0035] As a specific embodiment of the method described above of the present invention, the vacuum pump has sufficient pressure, and its relative vacuum degree is 0.1 - 0.9 atm.

[0036] The purpose of the elution carried out in step (4) of the above-mentioned method of the present invention is to remove impurities such as Al, Fe, Ti, etc., and serve as the elution blank before the peak emergence of Li.

[0037] In step (5) of the above-mentioned method of the present invention, those skilled in the art can reasonably set the magnitude of the negative pressure driving force required according to the on-site operation needs, and the pressure of the vacuum pump used in the present invention is sufficient to meet the magnitude requirements of the negative pressure driving force required during the actual operation process.

[0038] As a specific embodiment of the above-mentioned method of the present invention, in step (5), a sample dissolution tank is used to collect the lithium-containing solution, and the lithium-containing solution includes the eluents corresponding to before and after the appearance of the Li signal in liquid chromatography to ensure the complete recovery of Li.

[0039] As a specific embodiment of the above-mentioned method of the present invention, the lithium-containing solution is 1 - 5 mL of the eluent before the appearance of the Li signal and 1 - 5 mL of the eluent after the appearance of the Li signal in liquid chromatography.

[0040] As a specific embodiment of the above-mentioned method of the present invention, the method includes the following specific steps:

[0041] (1) Add 15 - 20 mL of 6N hydrochloric acid to the chromatographic microcolumn, drip until nearly dry, and then add 15 - 20 mL of deionized water to the chromatographic microcolumn to complete the resin washing process;

[0042] (2) Use a pipette to add 1 mL of 0.2 - 0.7N hydrochloric acid to the chromatographic microcolumn to balance the acidity environment of the cation exchange resin, and the acid solution used to balance the acidity environment of the cation exchange resin is the same as the acid solution used to dissolve the target geological sample;

[0043] (3) Dissolve an appropriate amount of the target geological sample in 200 - 400 μL of 0.2 - 0.7N hydrochloric acid. The content of Li in the obtained target geological sample solution is 10 - 500 ng. Use a pipette to suck the target geological sample solution and add it to the chromatographic microcolumn, drip until nearly dry, and then add 1 mL of 0.2 - 0.7N hydrochloric acid to the chromatographic microcolumn, drip until nearly dry;

[0044] (4) Use 0.2 - 0.7N hydrochloric acid to elute the cation exchange resin, and the amount of the hydrochloric acid used is 17 mL; in steps (1) - (4), a beaker is used to collect the waste liquid;

[0045] (5) Continue to use 0.2 - 0.7N hydrochloric acid to elute the cation exchange resin and use a sample dissolution tank to collect the lithium-containing solution, and the amount of the hydrochloric acid used is 18 mL;

[0046] The lithium-containing solution is 1-5 mL of the eluent before the Li signal appears and 1-5 mL of the eluent after the Li signal appears in liquid chromatography;

[0047] Among them, the washing process in step (1) and the elution processes in steps (4) and (5) require a negative pressure driving force provided by a vacuum pump, that is, the vacuum pump is in an open state in steps (1), (4), and (5); while the equilibration process in step (2) and the sample loading process in step (3) do not require a negative pressure driving force provided by a vacuum pump, that is, the vacuum pump is in a closed state in steps (2) and (3).

[0048] As a specific embodiment of the method described above in the present invention, in steps (2), (3), (4), and (5), the concentration of the hydrochloric acid is 0.5 N.

[0049] As a specific embodiment of the method described above in the present invention, in step (1), 15-20 mL of hydrochloric acid with a concentration of 6 N is added to the chromatographic microcolumn, and the duration is 5-20 min.

[0050] In the method described above in the present invention, "dripping to near dry" means that almost all of the target liquid is dripped into the corresponding system, and those skilled in the art can reasonably judge "near dry" according to the actual situation. For example, in step (1) of specific embodiment 2 of the present invention, 15-20 mL of hydrochloric acid with a concentration of 6 N is added to the chromatographic microcolumn, and after 5-20 min, it is considered to be dripped to near dry.

[0051] The system and method provided by the present invention adopt a speed regulation mechanism driven by vacuum negative pressure (the pressure of the used vacuum pump is sufficient, and its relative vacuum degree is 0.1-0.9 atm), which significantly increases the reagent flow rate. Compared with the Li element separation technology of the chromatographic microcolumn method commonly used in current existing geochemical ultra-clean laboratories, the system and method provided by the present invention achieve efficient and rapid separation of Li elements in geological samples (for a chromatographic microcolumn with a length of 10-40 cm, the sample elution and collection time takes about 5-30 minutes); and the system and method provided by the present invention have good experimental repeatability and consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0053] Figure 1 It is a schematic diagram of element separation by cation exchange chromatography.

[0054] Figure 2 This is a schematic structural diagram of the rapid lithium element separation system driven by vacuum negative pressure provided by the embodiments of the present invention.

[0055] Main reference numerals description:

[0056] 1 - Chromatographic microcolumn;

[0057] 2 - Pipeline valve;

[0058] 3 - Vacuum device;

[0059] 4 - Vacuum pipeline;

[0060] 5 - Beaker or sample dissolution tank;

[0061] 6 - Vacuum pump. Detailed implementation manners

[0062] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the following detailed description of the technical solution of the present invention is provided in conjunction with the following specific embodiments, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0063] It should be noted that the term "including" and any of its variations in the description and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps, units, or components does not necessarily have to be limited to those steps, units, or components clearly listed, but may include other steps, units, or components that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0064] In the present invention, the orientation or positional relationship indicated by terms such as "upper", "lower", and "inner" is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit that the indicated device, element, or component must have a specific orientation, or be constructed and operated in a specific orientation.

[0065] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0066] Embodiment 1

[0067] This embodiment provides a rapid lithium element separation system driven by vacuum negative pressure. Among them, the schematic structural diagram of the rapid lithium element separation system driven by vacuum negative pressure is as Figure 2As shown, from Figure 2 it can be seen that it includes: a chromatographic microcolumn 1, a beaker or sample dissolution tank 5, a vacuum pump 6 and a vacuum device 3; the chromatographic microcolumn 1 is filled with cation exchange resin, and both its upper and lower ends are sealed with PE sieve plates; the beaker or sample dissolution tank 5 is located inside the vacuum device 3; the lower end outlet of the chromatographic microcolumn 1 is connected to the beaker or sample dissolution tank 5 through an outlet pipeline via a pipeline valve 2 and through the top cover of the vacuum device 3; an opening is provided on the side of the vacuum device 3 and is connected to the vacuum pump 6 through a vacuum pipeline 4;

[0068] The beaker or sample dissolution tank 5 is used to receive the waste liquid or lithium-containing solution flowing out from the chromatographic microcolumn 1.

[0069] In this embodiment, the vacuum device 3 is a sealed box made of transparent polycarbonate. The sealed box has a detachable top cover. An opening is provided on the top cover, and a Luer connector is fixedly connected to the opening. The outlet pipeline is connected to the vacuum device 3 through the Luer connector.

[0070] In this embodiment, the Luer connector is fixedly connected to the opening through a sealant.

[0071] In this embodiment, the material of the sample dissolution tank is Teflon or polypropylene.

[0072] In this embodiment, the inner diameter of the chromatographic microcolumn is 3.5 mm and the length is 33 cm.

[0073] In this embodiment, the chromatographic microcolumn is filled with 3 mL of AG50W-X12 resin, and the mesh number of the resin is 200 - 400.

[0074] In this embodiment, the PE sieve plate is a 20-μm PE sieve plate.

[0075] Example 2

[0076] This embodiment provides a method for rapid separation of lithium element driven by vacuum negative pressure. The method uses the vacuum negative pressure driven lithium element rapid separation system provided in Example 1, and it includes the following specific steps:

[0077] (1) Add 15 - 20 mL of hydrochloric acid with a concentration of 6N to the chromatographic microcolumn and drip until nearly dry; then add 15 - 20 mL of deionized water to the chromatographic microcolumn to complete the resin washing process;

[0078] (2) Add 1 mL of hydrochloric acid with a concentration of 0.5N to the chromatographic microcolumn through a pipette and drip until nearly dry to balance (maintain) the acidity environment of the cation exchange resin, and the acid solution used to maintain the acidity environment of the cation exchange resin is the same as the acid solution used to dissolve the target geological sample and the acid solution used as the eluent;

[0079] (3) Dissolve an appropriate amount of the target geological sample in 200 - 400 μL of hydrochloric acid with a concentration of 0.5 N. The content of Li in the obtained target geological sample solution is 10 - 500 ng. Use a pipette to aspirate the target geological sample solution and add it to the chromatographic microcolumn until it is nearly dry, and then add 1 mL of hydrochloric acid with a concentration of 0.5 N to the chromatographic microcolumn. When performing pipetting operations, keep the pipette body vertical, and the pipetting action should be gentle to avoid reagent splashing caused by too fast actions.

[0080] (4) Elute the cation exchange resin with 17 mL of hydrochloric acid with a concentration of 0.5 N. During steps (1) - (4), collect the waste liquid in a beaker.

[0081] (5) Continue to elute the cation exchange resin with 18 mL of hydrochloric acid with a concentration of 0.5 N and collect the lithium-containing solution in a sample dissolution tank.

[0082] The lithium-containing solution is 1 - 5 mL of the eluate before the Li signal appears and 1 - 5 mL of the eluate after the Li signal appears in liquid chromatography to ensure complete recovery of Li.

[0083] Among them, the washing process in step (1) and the elution processes in steps (4) and (5) require a negative pressure driving force provided by a vacuum pump, that is, the vacuum pump is in the on state in steps (1), (4), and (5); while the equilibration process in step (2) and the sample loading process in step (3) do not require a negative pressure driving force provided by a vacuum pump, that is, the vacuum pump is in the off state in steps (2) and (3).

[0084] (6) Place the sample dissolution tank containing the lithium-containing solution in step (5) on a muffle furnace, evaporate to dryness at 90 °C, and then add nitric acid with a mass concentration of 2% to dissolve the dried product to complete the separation operation of Li element and wait for on-machine testing.

[0085] Compared with the chromatographic microcolumn method Li element separation technology commonly used in current geochemical ultra-clean laboratories, the system and method of this embodiment of the present invention provide a speed regulation mechanism driven by vacuum negative pressure, significantly increasing the reagent flow rate and realizing efficient and rapid separation of Li element in geological samples. For example, in Example 2, a 33 cm long chromatographic microcolumn (filled with 3 mL of cation exchange resin) is used to separate Li element in geological samples. Without additional driving, the natural flow rate of the reagent is much lower than 0.1 mL / minute; after adding a vacuum device, the flow rate can reach 10 mL / minute and is fully adjustable. Currently, many laboratories use a reagent flow rate of about 0.1 mL / minute when manually separating Li element, while modern high-pressure liquid chromatographs usually select a reagent flow rate of 1 mL / minute.

[0086] After the system provided by the present invention is equipped with an additional vacuum device, the reagent flow rate can be freely selected within the range of 0.1 - 1 mL / min, and can even be selected within the range of 1 - 10 mL / min; and according to the Van Deemter empirical equation, the optimal flow rate range that satisfies the chromatographic column efficiency can be determined through experiments. With a large adjustable range of the flow rate, there are relatively rich experimental routes to choose from, including a large selection range for the length of the chromatographic microcolumn, the resin capacity filled, the types and concentrations of reagents, etc. On the basis of ensuring the separation efficiency, the vacuum negative pressure drive can easily complete the entire Li element separation experiment within one day, where the entire Li element separation experiment includes the evaporation treatment of a small amount of samples, as well as the washing, equilibration, sample loading, elution, and Li element collection of the resin.

[0087] In summary, in the system and method of the embodiments of the present invention, the vacuum pump provides sufficient driving force, which is much greater than the self-gravity drive of the chromatographic microcolumn. Therefore, the small differences between chromatographic microcolumns, the influence of resin packing effect, etc. can be ignored, and the flow rate difference of the reagents used in the experiment is very stable. In the traditional Li separation method used in the current laboratory, the chromatographic microcolumn has no drive speed regulation mechanism, and the experimental repeatability and consistency are poor. For 10 - 12 columns in one experiment, the flow rate difference of the reagents is 1 / 3 or even greater; and the repeatability of multiple experiments on the same column is also not good. After adding the vacuum negative pressure drive in the system and method of the embodiments of the present invention, the reagent flow rates are highly consistent. For example, in the elution process of a reagent with an eluent volume of 35 mL, the difference before and after is no more than 1 mL, and the experimental repeatability and consistency are very good.

[0088] As described above, the above are only specific embodiments of the present invention, and the scope of the invention implementation cannot be limited by them. Therefore, the replacement of equivalent components, or the equivalent changes and modifications made according to the scope of the present invention patent protection, should still fall within the scope covered by this patent. In addition, the technical features in the present invention, between technical features, between technical features and technical inventions, and between technical inventions can be freely combined and used.

Claims

1. A method for rapid separation of lithium element driven by vacuum negative pressure, characterized in that, the method utilizes a rapid lithium element separation system driven by vacuum negative pressure, wherein the rapid lithium element separation system driven by vacuum negative pressure includes: a chromatographic microcolumn, a beaker, a sample dissolution tank, a vacuum pump and a vacuum device; the chromatographic microcolumn is filled with cation exchange resin, and both its upper and lower ends are sealed with PE sieve plates; the beaker or the sample dissolution tank is located inside the vacuum device; the lower end outlet of the chromatographic microcolumn is connected to the beaker or the sample dissolution tank through an outlet pipeline via a pipeline valve and through the top cover of the vacuum device; the side of the vacuum device is provided with an opening and is connected to the vacuum pump through a vacuum pipeline; the beaker or the sample dissolution tank is used to collect the waste liquid or the lithium-containing solution flowing out of the chromatographic microcolumn; the length of the chromatographic microcolumn is 10 - 40 cm; the chromatographic microcolumn is filled with 3 - 6 mL of AG50W-X12 resin, and the mesh number of the resin is 200 - 400; wherein, the method includes: (1) Washing the cation exchange resin in the chromatographic microcolumn with concentrated acid reagent and deionized water respectively; (2) Adding acid solution to the chromatographic microcolumn with a pipette to balance the acidity environment of the cation exchange resin, and the acid solution used to balance the acidity environment of the cation exchange resin is the same as the acid solution used to dissolve the target geological sample; (3) Dissolving the target geological sample in the acid solution, sucking the target geological sample solution with a pipette and adding it to the chromatographic microcolumn, and then adding acid solution to the chromatographic microcolumn; (4) Eluting the cation exchange resin with an eluent; wherein in steps (1) - (4), a beaker is used to collect the waste liquid; (5) Continuing to elute the cation exchange resin with the eluent and using a sample dissolution tank to collect the lithium-containing solution, and the lithium-containing solution is 1 - 5 mL of the eluent before the Li signal appears and 1 - 5 mL of the eluent after the Li signal appears in liquid chromatography; wherein, the washing process in step (1) and the elution processes in steps (4) and (5) require a negative pressure driving force provided by the vacuum pump; The flow rates of the concentrated acid reagent, deionized water in step (1), the eluent in step (4) and the eluent in step (5) are all adjustable within the range of 0.1 - 10 mL / minute; The concentrated acid reagent in step (1) is concentrated hydrochloric acid, the acid solution in steps (2) and (3) is hydrochloric acid, and the eluent used in steps (4) and (5) is hydrochloric acid; The vacuum pump has sufficient pressure, and its relative vacuum degree is 0.1 - 0.9 atm.

2. The method according to claim 1, characterized in that, the method includes the following specific steps: (1) Adding 15 - 20 mL of hydrochloric acid with a concentration of 6N to the chromatographic microcolumn, dripping until almost dry, and then adding 15 - 20 mL of deionized water to the chromatographic microcolumn to complete the resin washing process; (2) Adding 1 mL of hydrochloric acid with a concentration of 0.2 - 0.7N to the chromatographic microcolumn with a pipette to balance the acidity environment of the cation exchange resin, and the acid solution used to balance the acidity environment of the cation exchange resin is the same as the acid solution used to dissolve the target geological sample; (3) Dissolve an appropriate amount of the target geological sample in 200 - 400 μL of hydrochloric acid with a concentration of 0.2 - 0.7 N. The content of Li in the obtained target geological sample solution is 10 - 500 ng. Use a pipette to aspirate the target geological sample solution and add it to the chromatographic microcolumn, drip until nearly dry, then add 1 mL of hydrochloric acid with a concentration of 0.2 - 0.7 N to the chromatographic microcolumn and drip until nearly dry; (4) Elute the cation exchange resin with hydrochloric acid with a concentration of 0.2 - 0.7 N, and the amount of the hydrochloric acid used is 17 mL; wherein, in steps (1) - (4), a beaker is used to collect the waste liquid; (5) Continue to elute the cation exchange resin with hydrochloric acid with a concentration of 0.2 - 0.7 N and collect the lithium-containing solution with a sample dissolution tank, and the amount of the hydrochloric acid used is 18 mL; The lithium-containing solution is 1 - 5 mL of the eluate before the appearance of the Li signal and 1 - 5 mL of the eluate after the appearance of the Li signal in liquid chromatography; Among them, the washing process in step (1) and the elution processes in steps (4) and (5) require a vacuum pump to provide negative pressure driving force.

3. The method according to claim 2, characterized in that, in step (2), step (3), step (4) and step (5), the concentration of the hydrochloric acid is 0.5 N.

4. The method according to any one of claims 1 - 3, characterized in that, the vacuum device is a sealed box made of transparent polycarbonate. The sealed box has a detachable top cover. An opening is provided on the top cover, and a Luer connector is fixedly connected to the opening. The outlet pipeline is communicated with the vacuum device through the Luer connector.

5. The method according to claim 4, characterized in that, the Luer connector is fixedly connected to the opening through a sealant.

6. The method according to any one of claims 1 - 3, characterized in that, the material of the sample dissolution tank is Teflon or polypropylene.

7. The method according to any one of claims 1 - 3, characterized in that, the PE sieve plate is a 20 - μm PE sieve plate.

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