Quantitative identification method for rare earth-loaded nanoparticles in weathered crust

Abstract

The invention discloses a quantitative identification method for rare earth-loaded nanoparticles in a weathered crust, and relates to the field of geology. According to the method, a weathering crust sample flows through a hollow fiber flow field flow separation system along with a current-carrying liquid, the focusing time of the current-carrying liquid is controlled to be 4-14 min, the radial flow velocity of the current-carrying liquid is controlled to be 0.15-0.65 mL / min, the axial flow velocity of the current-carrying liquid is controlled to be 0.1-1.0 mL / min, and separation of rare earth-loaded nanoparticles in the weathering crust sample is achieved; and carrying out qualitative and quantitative analysis on the separated rare earth-loaded nanoparticles through an inductively coupled plasma mass spectrometer to obtain the types and contents of the rare earth-loaded nanoparticles with different particle sizes. By adopting the method provided by the invention, separation and quantitative analysis of the rare earth-loaded nanoparticles in the weathered crust can be realized, and the analysis efficiency and accuracy are improved.

Description

Technical Field

[0001] This application relates to the technical field of geology, and particularly to a method for quantitatively identifying rare earth-bearing nano-particles in weathered crusts. Background Art

[0002] Heavy rare earths are scarce strategic resources for the development of modern high-tech. Ion-adsorption rare earth deposits provide more than 90% of the world's heavy rare earth resources. In recent years, a series of light and heavy rare earth symbiotic, or even heavy rare earth deposits formed by the weathering of light rare earth granites have been discovered. What causes the differentiation of light and heavy rare earths during the weathering of granite, and ultimately the enrichment of ore formation and the occurrence form of rare earth elements are the prerequisites for deeply understanding the formation mechanism of such deposits and scientifically exploiting and utilizing such deposits.

[0003] In ion-adsorption rare earth deposits, it is generally believed that rare earth ions (REE) mainly migrate in the form of cations or coordination complexes, and then are adsorbed and enriched by clay minerals or iron / manganese (hydr)oxides, thus forming deposits with industrial exploitation value. However, some studies have pointed out that REE not only appears in the form of ion adsorption phase or complex, but also exists in the form of secondary nano-rare earth particles and is adsorbed on the surface of clay minerals or iron-manganese oxides. However, relying solely on traditional whole-rock mineralogy and geochemical analysis techniques and conventional research methods is not sufficient to fully reveal the relationship between REE-bearing nano-particles and clay minerals and iron-manganese oxides. Therefore, there is an urgent need to develop a method for separating and characterizing rare earth-bearing nano-particles in weathered crusts. Summary of the Invention

[0004] Aiming at the problems pointed out in the background art, the purpose of this application is to provide a method for quantitatively identifying rare earth-bearing nano-particles in weathered crusts, so as to realize the separation and quantitative analysis of rare earth-bearing nano-particles in weathered crusts and improve the analysis efficiency and accuracy.

[0005] To achieve the above purpose, the present application provides the following solutions.

[0006] The present application provides a method for quantitatively identifying rare earth-bearing nano-particles in weathered crusts, including:

[0007] Separating and purifying rare earth-bearing nano-particles in weathered crusts through a hollow fiber flow field flow fractionation system; qualitatively and quantitatively analyzing the separated rare earth-bearing nano-particles by an inductively coupled plasma mass spectrometer to obtain the types and contents of rare earth-bearing nano-particles with different particle sizes.

[0008] Specifically, the weathered crust sample flows through the hollow fiber flow field flow separation system along with the carrier liquid, and the focusing time of the carrier liquid is controlled to be 4 - 14 min, the radial flow rate of the carrier liquid is controlled to be 0.15 - 0.65 mL / min, and the axial flow rate of the carrier liquid is controlled to be 0.1 - 1.0 mL / min, so as to realize the separation of rare earth nanoparticle-loaded in the weathered crust sample.

[0009] Optionally, the weathered crust sample is introduced by a handheld sampler and enters the hollow fiber flow field flow separation system along with the carrier liquid.

[0010] Optionally, the injection volume of the weathered crust sample is 20 - 200 μL.

[0011] Optionally, the carrier liquid is one of ultrapure water, 0.02 mmol / L sodium carbonate solution, and 0.1% FL-70. Preferably, it is found in relevant experiments that the separation effect is better when ultrapure water is used as the carrier liquid.

[0012] Optionally, the focusing time of the carrier liquid is 8 min.

[0013] Optionally, the radial flow rate of the carrier liquid is 0.45 mL / min.

[0014] Optionally, the axial flow rate of the carrier liquid is 0.50 mL / min.

[0015] Optionally, the hollow fiber flow field flow separation system includes a hollow fiber flow field flow separation channel; the hollow fiber flow field flow separation channel is made of polyethersulfone.

[0016] Optionally, the length of the hollow fiber flow field flow separation channel is 20 cm, the inner diameter is 0.90 mm, the outer diameter is 1.50 mm, and the molecular weight cut-off is 10 kDa.

[0017] Optionally, the hollow fiber flow field flow separation system further includes:

[0018] A plunger pump, associated with the hollow fiber flow field flow separation channel, to pump the carrier liquid to flow in the hollow fiber flow field flow separation channel;

[0019] A metering valve, associated with the hollow fiber flow field flow separation channel, to control the flow rate ratio at the inlet and outlet of the hollow fiber membrane during the focusing process;

[0020] A valve, associated with the hollow fiber flow field flow separation channel, to control the switching of the focusing process, separation process, and elution process of the carrier liquid in the hollow fiber flow field flow separation channel.

[0021] According to the specific embodiments provided in this application, the following technical effects are disclosed in this application.

[0022] A method for quantitatively identifying rare earth-loaded nanoparticles in weathered crust provided by this application uses the combined technology of hollow fiber flow field-flow fractionation-inductively coupled plasma mass spectrometry. By optimizing the experimental conditions of the focusing time of the carrier liquid and the radial and axial flow rates, continuous on-line separation and quantitative characterization of rare earth-loaded nanoparticles in the complex weathered crust are achieved. It has the advantages of simple operation, little interference from the sample matrix, high analysis efficiency and high analysis accuracy, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic flow chart of a method for quantitatively identifying rare earth-loaded nanoparticles in weathered crust according to this application;

[0025] Figure 2 It is a schematic diagram showing the influence of the type of carrier liquid on the separation and analysis of rare earth-loaded nanoparticles in weathered crust in the embodiment of this application;

[0026] Figure 3 It is a schematic diagram showing the influence of the focusing time on the separation and analysis of rare earth-loaded nanoparticles in weathered crust in the embodiment of this application;

[0027] Figure 4 It is a schematic diagram showing the influence of the radial flow rate on the separation and analysis of rare earth-loaded nanoparticles in weathered crust in the embodiment of this application;

[0028] Figure 5 It is a schematic diagram showing the influence of the axial flow rate on the separation and analysis of rare earth-loaded nanoparticles in weathered crust in the embodiment of this application;

[0029] Figure 6 It is a schematic diagram showing the quantitative analysis results of Ce, Mn, and Fe elements in the embodiment of this application;

[0030] Figure 7 It is a schematic diagram showing the quantitative analysis results of Ce and Al elements in the embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are only some of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0032] The objective of this application is to propose a method for quantitatively identifying rare earth-bearing nanoparticles in weathered crust. Based on the hollow fiber flow field flow fractionation technology, it can separate and detect the content and occurrence state of rare earth-bearing nanoparticles in weathered crust, realizing the separation and quantitative analysis of rare earth-bearing nanoparticles in weathered crust, and improving the analysis efficiency and accuracy.

[0033] To make the above objectives, features, and advantages of this application more obvious and understandable, the following further detailed description of this application will be given in combination with the accompanying drawings and specific embodiments.

[0034] In an exemplary embodiment, this application provides a method for quantitatively identifying rare earth-bearing nanoparticles in weathered crust, as Figure 1 shown, including the following steps 1 to 2.

[0035] Step 1: The weathered crust sample flows through the hollow fiber flow field flow fractionation system along with the carrier liquid, and the focusing time of the carrier liquid is controlled to be 4 - 14 min, the radial flow rate of the carrier liquid is controlled to be 0.15 - 0.65 mL / min, and the axial flow rate of the carrier liquid is controlled to be 0.1 - 1.0 mL / min, so as to realize the separation of rare earth-bearing nanoparticles in the weathered crust sample.

[0036] This application uses a hollow fiber flow field flow fractionation system (HF5) to separate, purify, and characterize rare earth-bearing nanoparticles (such as organic macromolecules, clay minerals, iron and manganese oxides, and independent rare earth nanoparticles) in weathered crust.

[0037] Field Flow Fractionation (FFF) is a separation technique similar to chromatography proposed by Giddings in 1966. The hollow fiber flow field flow fractionation system (HF5) is a new type of FFF technology, which also elutes by applying a flow field in the channel. The mobile phase introduced into the HF5 channel is divided into two parts: one part of the carrier liquid passes through the fiber wall surface in the form of radial flow, and the rest of the mobile phase flows along the fiber axis. Under the action of the force generated by the radial flow passing through the porous wall of the fiber membrane, the particulate matter maintains an equilibrium position in the channel, while the axial flow of small molecules (such as ions) moving along the fiber axis is eluted first, and the particles are eluted in turn according to their size later.

[0038] Specifically, the hollow fiber flow field flow fractionation system adopted in this application includes a hollow fiber flow field flow fractionation channel, and this hollow fiber flow field flow fractionation channel is made of polyethersulfone.

[0039] In an exemplary embodiment, the length of the hollow fiber flow field flow fractionation channel is 20 cm, the inner diameter is 0.90 mm, the outer diameter is 1.50 mm, and the molecular weight cut-off of this hollow fiber flow field flow fractionation channel is 10 kDa.

[0040] Further, the hollow fiber flow field flow separation system further includes:

[0041] A plunger pump, associated with the hollow fiber flow field flow separation channel, for pumping the carrier liquid to flow in the hollow fiber flow field flow separation channel;

[0042] A metering valve, associated with the hollow fiber flow field flow separation channel, for controlling the flow rate ratio of the inlet and outlet of the hollow fiber membrane during the focusing process;

[0043] A valve, associated with the hollow fiber flow field flow separation channel, for controlling the switching of the focusing process, separation process, and elution process of the carrier liquid in the hollow fiber flow field flow separation channel.

[0044] During the focusing process, the nanoparticles migrate towards the wall of the separation channel under the action of the flow field and Brownian motion, and finally reach equilibrium at a certain distance from the wall of the separation channel. At the same time, coexisting ions, molecules, etc. are dialyzed out of the separation channel, realizing on-line purification of the sample matrix.

[0045] The weathered crust sample is usually a weathered crust (rare earth) nanoparticle suspension sample, introduced by a hand-held sampler, and enters the hollow fiber flow field flow separation system with the carrier liquid. The injection volume of the weathered crust sample is 20 - 200 μL. More preferably, the injection volume of the weathered crust rare earth nanoparticle suspension sample is 100 μL.

[0046] The carrier liquid is one of ultrapure water, 0.02 mmol / L sodium carbonate solution, and 0.1% FL-70. Figure 2 This is a schematic diagram of the influence of the type of carrier liquid on the separation and analysis of rare earth nanoparticles in the weathered crust in the embodiments of this application. The abscissa is the experimental time, and the ordinate is the signal intensity directly measured by ultraviolet. From Figure 2 The experimental results shown can be seen that when ultrapure water is used as the carrier liquid, the separation effect is the best. Therefore, more preferably, the carrier liquid is selected as ultrapure water.

[0047] In the hollow fiber flow field flow separation technology, the focusing time of the carrier liquid focusing process is related to the time required for the target substance to reach the equilibrium state in the separation channel at a certain radial flow rate. Figure 3 Shows the influence of the focusing time on the separation and analysis of rare earth nanoparticles in the weathered crust. The abscissa is the experimental time, and the ordinate is the signal intensity. The time marked on each measurement curve is the focusing time. From Figure 3 It can be seen that insufficient focusing time will cause the particles to be eluted before reaching the equilibrium position, while too long focusing time will prolong the analysis process and increase the interaction between the particles and the membrane, possibly resulting in particle loss.

[0048] Therefore, in this application, the focusing time of the carrier fluid is controlled to be 4 - 14 min. More preferably, the focusing time of the carrier fluid is 8 min. If the set focusing time is insufficient, it will cause the weathered crust nanoparticles to start being eluted before they are stabilized to the expected equilibrium position, which not only affects the separation efficiency but may also trigger a memory effect due to the remaining substances in the sample loop. If the set focusing time exceeds the required value, then after the weathered crust nanoparticles reach their equilibrium position in the separation channel, they will still stay in the channel, which not only unnecessarily lengthens the duration of the entire analysis process but also increases the chance of interaction between the weathered crust nanoparticles and the hollow fiber membrane, and this interaction may cause partial loss of the nanoparticles.

[0049] The radial flow rate of the carrier fluid provides the flow field required for separation. The existence of this flow field enables sample microparticles of different sizes to enter flow layers with different velocities, thereby achieving separation. Figure 4 Shows the influence of the radial flow rate on the separation and analysis of rare earth - carrying nanoparticles in the weathered crust. The abscissa is the experimental time, and the ordinate is the signal intensity. The corresponding radial flow rates are marked on each measurement curve. Figure 4 It can be seen that if the radial flow rate is too small, the microparticles cannot maintain an equilibrium distribution in the channel, resulting in incomplete elution of the particulate matter and early peak emergence; if the radial flow rate is too large, the microparticles approach the membrane, increasing the interaction, leading to peak broadening and an extended separation time.

[0050] Therefore, in this application, the radial flow rate of the carrier fluid is controlled to be 0.15 - 0.65 mL / min. More preferably, the radial flow rate of the carrier fluid is 0.45 mL / min. The magnitude of the radial flow rate corresponds to the strength of the applied flow field. When the applied flow field is too small (small radial flow rate), the weathered crust nanoparticles cannot maintain an equilibrium distribution in the channel, with poor retention, resulting in the situation of incomplete elution of the particulate matter and early peak emergence. On the contrary, when the applied flow field is too large (large radial flow rate), the weathered crust nanoparticles also cannot maintain an equilibrium in the channel. The nanoparticles move towards the vicinity of the hollow fiber membrane, and the reduced distance between the microparticles and the membrane leads to enhanced interaction, and it is very likely that some nanoparticles will be adsorbed on the membrane, causing peak broadening and an extended separation time.

[0051] Furthermore, Figure 5 Shows the influence of the axial flow rate on the separation and analysis of rare earth - carrying nanoparticles in the weathered crust. The abscissa is the experimental time, and the ordinate is the signal intensity. The corresponding axial flow rates are marked on each measurement curve. Figure 5 It can be seen that if the axial flow rate is too small, it will cause incomplete elution of the microparticles and severe peak broadening; if the axial flow rate is too large, it will reduce the peak intensity of the microparticles and elute them together with the solvent.

[0052] Therefore, the axial flow rate of the carrier liquid in this application is controlled to be 0.1 - 1.0 mL / min. More preferably, the axial flow rate of the carrier liquid is 0.50 mL / min. The magnitude of the axial flow rate determines the magnitude of the elution rate. The smaller the axial flow rate, the smaller the elution rate, and some weathered crust nanoparticles are not completely eluted in the system, resulting in serious peak broadening. When the axial flow rate is too large, the elution rate is also large, the peak intensity of the weathered crust nanoparticles decreases, and the weathered crust nanoparticles will be eluted together with the solvent and cannot be separated, which is not conducive to the subsequent connection with the inductively coupled plasma mass spectrometer (ICP-MS).

[0053] This application uses HF5 to achieve the on-line separation and characterization of rare earth-bearing nanoparticles in the weathered crust with complex components. Compared with traditional separation methods, HF5 has the characteristics of continuous high-resolution separation of particulate matter, and at the same time can perform size characterization on the separated substances, and it has unique advantages compared with dynamic light scattering (DLS) and transmission electron microscopy (TEM). Although DLS is convenient to operate, there are large errors in the measurement of large-particle-size particles, and it measures the average size of the sample. TEM can directly observe the morphology of particulate matter, but its sample preparation operation is complex and the aggregation of the sample may be changed during the sample preparation process. Similarly, due to the limited observation range, all particulate size information cannot be obtained. There is no stationary phase in the HF5 channel, which is a mild separation method and will not affect the size and morphology of particulate matter.

[0054] Step 2: Qualitatively and quantitatively analyze the rare earth-bearing nanoparticles obtained by separation through an inductively coupled plasma mass spectrometer to obtain the types and contents of rare earth-bearing nanoparticles with different particle sizes.

[0055] The working principle of the inductively coupled plasma mass spectrometer (ICP-MS) is to convert the sample into an aerosol, evaporate, atomize and ionize it in the inductively coupled plasma, then accelerate and focus the ions through the ion optical system, and finally use the mass analyzer to separate the ions according to the mass-to-charge ratio and detect them by the detector to obtain element content information. In this application, ICP-MS is combined with HF5, and the rare earth-bearing nanoparticles separated by HF5 are directly detected in real time by ICP-MS, and the types and corresponding signal intensities (corresponding to element contents) of different rare earth elements in nanoparticles with different particle sizes can be determined.

[0056] Specifically, connect the sample discharge pipe of HF5 to the injection pipeline of ICP-MS, so that the nanoparticle sample separated by HF5 is continuously injected into the injection system of ICP-MS, and the element concentration of the continuously injected nanoparticles within a certain time period is measured by ICP-MS.

[0057] The rare earth-bearing nanoparticles studied in this application include nanoscale clay minerals, nanoscale iron and manganese oxides, independent rare earth nanoparticles, etc. That is to say, the rare earth-bearing nanoparticles may be adsorbed on nanoscale clay minerals and iron and manganese oxides in the form of REE ions, or may exist in the form of independent rare earth nanoparticles. Based on the quantitative analysis results obtained by ICP-MS, the relationship between nanoscale clay minerals, nanoscale iron and manganese oxides and independent rare earth nanoparticles can be further analyzed.

[0058] HF5 used in this application uses a hollow fiber membrane as the separation channel. During the field flow separation process, coexisting REE ions, Al ions, etc. are dialyzed out of the separation channel. Small-sized particles are closer to the axial liquid flow center than large-sized particles at equilibrium, so they will be eluted earlier than large-sized particles during the separation process, thus realizing the separation of particles of different sizes. By optimizing the experimental conditions of the radial flow rate and axial flow rate, the separation and quantification of rare earth-bearing nanoparticles in weathered crust are realized. The operation is simple, the analysis efficiency is high and the analysis accuracy is high. And the method of this application is less interfered by the sample matrix, and realizes the on-line separation and characterization of rare earth-bearing nanoparticles in weathered crust with complex components.

[0059] The following further illustrates the specific implementation mode of this application through specific embodiments.

[0060] In a specific embodiment, a hollow fiber membrane made of polyethersulfone (inner diameter 0.90 mm, outer diameter 1.50 mm, length 200 mm, cut-off molecular weight 10 kDa) is selected as the hollow fiber flow field flow separation channel. A plunger pump (1200, Agilent) is used for the high-precision transport of the mobile phase solution in field flow separation. A metering valve is used to control the flow rate ratio of the inlet and outlet of the hollow fiber membrane during the focusing process. Three-way valves and four-way valves are used to control the switching of the focusing, separation and elution processes. The weathered crust sample enters the flow path through a high-performance liquid chromatography (HPLC) manual microinjector (7752i, Hamilton) equipped with a quantitative loop (200 μL), and the carrier liquid is ultrapure water. During the focusing process, the radial flow rate is selected as 0.45 mL / min and the focusing time is 8 min. During the separation process, the radial flow rate is selected as 0.45 mL / min and the axial flow rate is 0.50 mL / min.

[0061] An inductively coupled plasma optical emission spectrometer (5110, Agilent) is used for the quantitative analysis of Ce, Mn, Fe elements, and the analysis results are as Figure 6 shown. It can be seen from Figure 6 the results that by using the quantitative identification method of rare earth-bearing nanoparticles in weathered crust provided by this application, extremely accurate quantitative analysis results of Ce, Mn, Fe elements are obtained. ByFigure 6 It can also be seen from the results that the representative REE element Ce has similar distribution peaks to Fe and Mn, indicating a close spatial dependence relationship between the two.

[0062] In another specific embodiment, an inductively coupled plasma optical emission spectrometer (5110, Agilent) is used for the quantitative analysis of Ce and Al elements, and the analysis results are as Figure 7 shown. It can be seen from Figure 7 the figure that the distribution peaks of the representative REE element Ce and Al partially overlap. The overlapping part indicates the occurrence relationship between the two. Nano-clay minerals promote the enrichment of REE through adsorption or ion exchange, and larger-sized rare earth-bearing nanoparticles may also exist in the form of non-clay mineral phases.

[0063] It should be noted that the terms "including", "comprising" or any other variants used in this application are intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or elements inherent to such a commodity or system. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the commodity or system including the said element.

[0064] The above description shows and describes several preferred embodiments of this application. However, as mentioned above, it should be understood that this application is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope contemplated by this application through the above teachings or the technology or knowledge in related fields. And any changes and variations made by those skilled in the art that do not depart from the spirit and scope of this application shall fall within the protection scope of the appended claims of this application.

[0065] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0066] Specific examples are used in this article to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A method for quantitatively identifying rare earth-bearing nanoparticles in weathered crust, characterized in that, Including: The weathered crust sample flows through the hollow fiber field-flow fractionation system along with the carrier fluid, and the focusing time of the carrier fluid is controlled to be 4 - 14 min, the radial flow rate of the carrier fluid is controlled to be 0.15 - 0.65 mL / min, and the axial flow rate of the carrier fluid is controlled to be 0.1 - 1.0 mL / min to achieve the separation of the rare-earth-loaded nanoparticles in the weathered crust sample; The separated rare-earth-loaded nanoparticles are qualitatively and quantitatively analyzed by an inductively coupled plasma mass spectrometer to obtain the types and contents of the rare-earth-loaded nanoparticles with different particle sizes.

2. The quantitative identification method of rare earth-loaded nanoparticles in weathered crust according to claim 1, characterized in that, The weathered crust sample is introduced by a handheld sampler and enters the hollow fiber field-flow fractionation system along with the carrier fluid.

3. The method for quantitatively identifying rare earth-bearing nanoparticles in weathered crust according to claim 2, characterized in that, The injection volume of the weathered crust sample is 20 - 200 μL.

4. The quantitative identification method of rare earth-bearing nano-particles in weathered crust according to claim 1, characterized in that, The carrier fluid is one of ultrapure water, 0.02 mmol / L sodium carbonate solution, and 0.1% FL-70.

5. The quantitative identification method of rare earth-loaded nanoparticles in weathered crust according to claim 1, characterized in that, The focusing time of the carrier fluid is 8 min.

6. The method for quantitatively identifying rare earth-loaded nanoparticles in weathered crust according to claim 1, characterized in that, The radial flow rate of the carrier fluid is 0.45 mL / min.

7. The quantitative identification method of rare earth-bearing nanoparticles in weathered crust according to claim 1, characterized in that, The axial flow rate of the carrier fluid is 0.50 mL / min.

8. The method for quantitatively identifying rare earth-loaded nanoparticles in weathered crust according to claim 1, characterized in that, The hollow fiber field-flow fractionation system includes a hollow fiber field-flow fractionation channel; The hollow fiber field-flow fractionation channel is made of polyethersulfone.

9. The method for quantitative identification of rare earth-bearing nanoparticles in weathered crust according to claim 8, characterized in that, The length of the hollow fiber field-flow fractionation channel is 20 cm, the inner diameter is 0.90 mm, the outer diameter is 1.50 mm, and the molecular weight cut-off is 10 kDa.

10. The method for quantitative identification of rare earth-loaded nanoparticles in weathered crust according to claim 8, characterized in that, The hollow fiber field-flow fractionation system further includes: A piston pump, associated with the hollow fiber field-flow fractionation channel to pump the carrier fluid to flow in the hollow fiber field-flow fractionation channel; A metering valve, associated with the hollow fiber field-flow fractionation channel to control the flow rate ratio at the inlet and outlet of the hollow fiber membrane during the focusing process; A valve, associated with the hollow fiber field-flow fractionation channel to control the switching of the focusing process, separation process, and elution process of the carrier fluid in the hollow fiber field-flow fractionation channel.

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