Preparation method of single-mineral Mars soil simulant based on Mars aerolite

Abstract

The invention belongs to the technical field of planetary science star soil simulant preparation, provides a preparation method of a single-mineral Mars soil simulant based on Mars meteorite, and prepares a high-fidelity Mars soil simulant based on Mars meteorite single-mineral characteristics and accurate matching of earth mineral materials. According to the method, comprehensive mineralogy and geochemical analysis technologies are used for accurately representing components and crystal structures of main minerals in Mars meteorite so as to represent mineralogy characteristics of Mars rocks, so that single minerals are screened on the earth and mixed and prepared in proportion, and a high-fidelity simulant closer to the characteristics of a surface weathered layer of the Mars is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of planetary science star soil simulants, and specifically relates to a method for preparing a single-mineral Martian soil simulant based on Martian meteorites. Background Art

[0002] With the deepening of Mars exploration, in-situ resource utilization (ISRU) has become an important technical means to reduce the cost of exploration, and high-fidelity Mars soil simulants are crucial for conducting related research. At present, no real Martian soil samples have been returned. Existing fire soil simulants such as the ES-x series, JSC Mars-1 and JMDS-1 are only prepared based on limited Mars probe detection data to meet spectral consistency or overall element consistency. However, as the basic unit of rock composition, minerals must have two basic properties: unique chemical composition and specific crystal structure, which are crucial for accurately reproducing the characteristics of extraterrestrial rocks. Material separation is the basis for accurate phase characterization. The lack of real samples leads to the lack of comprehensive characterization data of the target. The Mars data obtained by the Mars probe payload detection is the overall composition of Martian soil. The data accuracy is not as good as that of the ground laboratory, and it is impossible to achieve the fine characterization of the components of the sample in the ground laboratory. Therefore, the applicability of existing simulated fire soil in in-situ molding experiments is still greatly limited. In order to obtain high-fidelity fire soil simulants based on mineralogy, it is necessary to combine the existing detection data and further strengthen the fine research on the composition and crystal form of single minerals to provide a scientific material basis for future in-situ construction.

[0003] As the only sample that can directly study the Martian regolith, the geochemical and mineralogical characteristics of Martian meteorites can provide a scientific basis for the preparation of high-fidelity simulants. About 80% of the existing Martian meteorites are Shergottites, which have the characteristics of basalt widely distributed on the surface of Mars. Selecting Shergottites as the target of Martian rock simulation will provide reliable data support for the preparation of high-fidelity Martian soil simulants. Summary of the invention

[0004] In view of the problem that the existing Martian soil simulants have insufficient fidelity and lack comprehensive characterization of single samples, thus being unable to fully simulate the mineralogical and geochemical characteristics of Martian soil, the present invention proposes a method for preparing a single-mineral Martian soil simulant based on Martian meteorites. Based on the single-mineral characteristics of Martian meteorites, the earth's mineral materials are accurately matched to prepare a high-fidelity Martian soil simulant. Among them, comprehensive mineralogical and geochemical analysis techniques are used to accurately characterize the composition and crystal structure of the main minerals in Martian meteorites to represent the mineralogical characteristics of Martian rocks. Based on this, single minerals are screened on Earth and mixed and prepared in proportion to obtain a high-fidelity simulant that is closer to the characteristics of the Martian surface weathering layer.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a single-mineral Martian soil simulant based on Martian meteorites comprises the following steps:

[0007] Step S1: Perform micro-area analysis on Martian meteorites to select single earth minerals required for preparing Martian soil simulant;

[0008] Step S2: purify the target single mineral from the Martian meteorite and compare and analyze it with the single mineral on Earth;

[0009] Step S3: preparing a Martian soil simulant;

[0010] Step S4: Conduct an overall fidelity assessment of the Martian soil simulant.

[0011] Preferably, the step S1 specifically includes:

[0012] Step S1-1: preparing a mineral thin section sample from a Martian meteorite;

[0013] Step S1-2: Perform TIMA mineral composition analysis to determine the coarse categories and proportions of various Martian meteorite minerals in the Martian meteorite, and use Raman spectroscopy to further determine the fine categories of Martian meteorite minerals;

[0014] Step S1-3: Select the corresponding single earth mineral according to the subcategories of Martian meteorite minerals;

[0015] Step S1-4: Perform electron probe micro-area analysis on the Martian meteorite minerals and the single minerals on Earth respectively to determine whether the mineral sub-classifications of the two are consistent. If they are consistent, execute step S2; otherwise, return to step S1-3.

[0016] Preferably, the step S2 specifically includes:

[0017] Step S2-1: physically crushing the Martian meteorite and purifying the target single mineral using a physical separation method;

[0018] Step S2-2: Perform XRD analysis on the target single mineral and the earth single mineral respectively to determine whether the crystal structures of the two are consistent. If they are consistent, execute step S2-3, otherwise, return to step S1-3.

[0019] Step S2-3: Perform XRF analysis on the target single mineral and the earth single mineral respectively to obtain the overall elemental composition of the two, and calculate the FoM index of the earth single mineral. If the FoM index of the earth single mineral meets the requirements, execute step S3, otherwise, return to step S1-3.

[0020] Preferably, the step S3 specifically includes:

[0021] Step S3-1: Determine the proportion of each Earth single mineral in the Martian soil simulant according to the proportion of each Martian meteorite mineral obtained in step S1-2;

[0022] Step S3-2: weighing each single earth mineral and grinding it;

[0023] Step S3-3: Mix the single mineral particles of the Earth according to the proportion to obtain a Martian soil simulant.

[0024] Preferably, the step S4 specifically includes:

[0025] Step S4-1: performing XRF analysis on the Martian soil simulant to obtain the overall elemental composition;

[0026] Step S4-2: Calculate the FoM index of the Martian soil simulant. If the FoM index of the Martian soil simulant meets the requirements, a high-fidelity Martian soil simulant is obtained. Otherwise, return to step S3-1.

[0027] Preferably, the step S1-2 specifically includes:

[0028] (1) Scan the mineral thin section sample based on scanning electron microscopy and energy dispersive X-ray spectroscopy to quickly obtain the elemental composition of each pixel point and present it in the form of a backscattered electron image. The backscattered images of each pixel point are spliced ​​to obtain the backscattered image of the cross section of the complete mineral thin section sample. The grayscale is converted into an RGB image to intuitively obtain the mineral phase composition and distribution characteristics of the entire mineral thin section sample, and thus determine the rough category and proportion of each Martian meteorite mineral in the Martian meteorite;

[0029] (2) Based on the mineral phase composition and distribution characteristics in the backscattered electron image, the area of ​​each mineral phase is found under a light microscope, and a Raman spectrum mapping test is performed on each mineral phase area to obtain the Raman spectrum characteristics of each mineral phase, thereby determining the subcategories of Martian meteorite minerals.

[0030] Preferably, the step S1-4 specifically includes:

[0031] Perform electron probe microanalysis on each mineral phase region in the mineral thin section sample to obtain the end-member element composition of each mineral phase in the mineral thin section sample; perform electron probe microanalysis on the selected single earth mineral preparation to obtain the end-member element composition of the single earth mineral, and compare the two. If the end-member diagram of the single earth mineral falls within the range of the end-member diagram of the mineral phase in the mineral thin section sample, then the mineral subdivisions of the two are deemed to be consistent, and step S2 is executed; otherwise, return to step S1-3.

[0032] Preferably, the physical separation method in step S2-1 is magnetic separation or flotation separation.

[0033] Preferably, the criterion for judging whether the crystal structures of the two are consistent in step S2-2 is that the 2Theta angle difference corresponding to the three strongest peaks of the two is less than 1°.

[0034] Preferably, the FoM index Φ of the single mineral on the earth in step S2-3 is m The calculation is as follows:

[0035]

[0036] Among them, u i represents the mass fraction of element i in the target single mineral, v i represents the mass fraction of element i in a single mineral on Earth, and n represents the number of elements;

[0037] The conditions for the FoM index of a single mineral on Earth to meet the requirements are: Φ m >0.85.

[0038] Preferably, the FoM index Φ of the Martian soil simulant in step S4-2 is M The calculation is as follows:

[0039]

[0040] Among them, U j represents the mass fraction of element j in Martian meteorites, V j represents the mass fraction of element j in the Martian soil simulant, and N represents the number of elements;

[0041] The conditions for the FoM index of Mars soil simulant to meet the requirements are: Φ M ≥0.9.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] 1. Selection of the best reference: In the absence of real Martian soil samples, the present invention innovatively selected Martian meteorites as references. Martian meteorites are the only samples that can directly study the characteristics of Martian rocks and soil regolith at this stage. Their geochemical and mineralogical characteristics highly represent the actual conditions of the Martian surface, making them the best choice for preparing high-fidelity simulants.

[0044] 2. Scalable simulant standards: Single mineral raw materials are prepared by grinding, with adjustable particle size and mineral ratio. Future research can flexibly adjust its particle size and mineral composition according to different geological conditions on Mars to further improve its applicability.

[0045] 3. Cost saving: Martian meteorite resources are scarce and precious. This study only needs to use a very small amount of Martian meteorite samples to complete the analysis and characterization. Through comprehensive micro-area analysis technology, the mineralogical and geochemical properties can be fully acquired, which greatly reduces the demand for sample usage.

[0046] 4. Promote Mars exploration: Provide high-fidelity Mars soil simulants, provide a reliable experimental platform for research on on-site resource utilization (ISRU), in-situ construction, equipment durability testing, etc. of Mars missions, and promote the development of Mars exploration. Through high-precision Mars soil simulants, help verify the reliability of materials and processes used in Mars surface engineering missions, and lay a technical foundation for future human exploration of Mars. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. The features and advantages of the present invention can be more clearly understood by referring to the drawings. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 It is a flow chart of the method for preparing a single-mineral Martian soil simulant based on Martian meteorites of the present invention.

[0049] Figure 2 It is a schematic diagram of the method for preparing a single-mineral Martian soil simulant based on Martian meteorites according to the present invention.

[0050] Figure 3 is a backscattered electron image of a mineral thin section sample.

[0051] Figure 4 This is a post-processed RGB image of the backscattered electron image of a mineral thin section sample.

[0052] Figure 5 This is a comparison chart of mineral Raman spectra.

[0053] Figure 6 It is the result of the comparison of the end-member diagram range of mineral phases in single minerals on Earth and mineral thin section samples.

[0054] Figure 7 It is a micro-area XRD test of different target single minerals in Martian meteorites.

[0055] Figure 8 It is the XRD comparison result of the target single mineral and the earth single mineral. DETAILED DESCRIPTION

[0056] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0057] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0058] The present invention proposes a method for preparing a single-mineral Martian soil simulant based on Martian meteorites. Based on the single-mineral characteristics of Martian meteorites, a high-fidelity Martian soil simulant is prepared by using precise proportions of earth mineral materials, which solves the problems of the lack of target characteristics, insufficient fidelity and application limitations of the simulants in the prior art. The core of the present invention is to use comprehensive mineralogical and geochemical analysis techniques to accurately characterize the composition and crystal structure of the main minerals in Martian meteorites to represent the mineralogical characteristics of Martian rocks, and then screen single minerals on Earth, mix and prepare them in proportion to obtain a high-fidelity simulant that is closer to the characteristics of the Martian surface weathering layer. It mainly includes the following contents:

[0059] Comprehensive analysis of the mineralogical and geochemical properties of Martian meteorites: Comprehensive mineralogical and chemical composition analysis of Martian meteorites is performed using a variety of micro-characterization techniques (electron probe microanalysis (EPMA), Raman spectroscopy, X-ray diffraction (XRD), and X-ray fluorescence (XRF)). This detailed data collection is not implemented by existing simulated pyrosol preparation techniques because they only rely on limited remote sensing or Mars rover data.

[0060] The single mineral method is used to prepare simulated pyroclastic soil: Based on the analysis results, single minerals similar to those in Martian meteorites are selected from the earth's minerals, and the ratio and particle size of these minerals are precisely controlled to replicate the physical and chemical properties of Martian soil. This method not only makes the separation and characterization of the simulated material more accurate, which is something that the whole rock simulation method cannot achieve (the whole rock simulation method refers to searching for igneous rocks (magmatic rocks) on the earth that are similar to the composition elements of pyroclastic soil, which can only ensure the similarity of the overall elemental composition, but the phase composition and proportion are not the same). The present invention matches and screens single minerals on the basis of material separation, and then mixes them to ensure that the rock units (that is, the mineral level) are consistent, thereby achieving overall consistency.

[0061] Development of new fidelity assessment indicators: Introducing the fidelity assessment indicator of single mineral chemical composition (FoM), which quantifies the similarity between the single minerals of the simulant and the single minerals of the actual soil. This assessment method provides a new scientific standard for the development of single mineral-based simulants, which is an innovation not found in existing technologies.

[0062] Example 1

[0063] Use Figure 1-2 The method of preparing the Martian soil simulant BH-Mars-S is as follows:

[0064] 1. Preparation and microanalysis of Martian meteorites

[0065] Martian meteorites are made into mineral thin section samples, micro-area analysis is performed on the Martian meteorites, and single Earth minerals needed to prepare Martian soil simulants are selected.

[0066] (1) TIMA (Total Mineral Analysis): Based on scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy, the surface of the mineral thin section sample is scanned step by step. EDS can quickly obtain the elemental composition of each pixel point and present it in the form of backscattered electron images, such as Figure 3 As shown in the figure, the grayscale is further converted into an RGB image to intuitively obtain the mineral phase composition and distribution characteristics of the entire mineral thin section sample, as shown in the figure. Figure 4 As shown. Based on the EDS results, the mineral types can be roughly judged according to the different main element compositions of each mineral, such as pyroxene: Si, Fe, Mg, Ca, Al; feldspar: Si, Al, Ca, Na, K; olivine: Si, Fe, Mg; metal oxides: Fe (very little Si) (which is consistent with the main mineral composition of Mars detected by the Mars rover). Based on the energy spectrum characteristic peaks of these main elements, the major types of minerals can be judged.

[0067] (2) Raman spectroscopy analysis to quickly and non-destructively obtain mineral identification characteristics: Based on the distribution of mineral phases in the backscattered electron image of TIMA (such as Figure 3 ), according to the outline and crack characteristics of each contrast (grayscale) phase, under the Raman spectrum microscope, at a magnification of 50X, find the area of ​​the corresponding phase, perform a point selection test of the Raman spectrum, and obtain the Raman spectrum characteristics of the mineral phase. At this time, according to the results of mineral phase identification (i.e. pyroxene, feldspar, olivine, iron oxide minerals, etc.), select various mineral samples on the earth, and compare the Raman spectra one by one to ensure that the peak position and shape can correspond to each other, and determine the single mineral on the earth. The comparison process is as follows Figure 5 shown.

[0068] (3) Electron probe microanalysis (EPMA) is a high-precision quantitative analysis of mineral phase composition to determine the element content of each mineral phase: Based on the Raman point selection test of different mineral phase regions of the Martian meteorite in (2), EPMA test is performed at the same location to obtain high-precision end-member element composition information of each mineral in the Martian meteorite; the single mineral preparation of the Earth determined by Raman spectroscopy in (2) is also subjected to EPMA test and compared with the end-member elements of each mineral phase in the Martian meteorite, such as Figure 6The end-member elements of the measured minerals are projected onto the ternary / binary diagram, and the different areas where they fall represent different mineral classifications (taking pyroxene as an example, according to the different ratios of Fe, Mg, and Ca, they are divided into diopside, calcium-iron pyroxene, and ordinary pyroxene. The element content of the mineral has a significant impact on its in-situ construction performance. For example, the iron content will affect its melting point. Therefore, it is necessary to ensure the consistency of the end-member element ratio range of the single mineral in the simulant). This verifies the consistency of the selected single mineral on Earth and the mineral phase subdivision in the Martian meteorite.

[0069] 2. Martian meteorite crushing and single mineral purification

[0070] (1) Considering that the subsequent XRD and XRF tests require a large amount of samples, the mineral thin section sample micro-area of ​​the Martian meteorite cannot meet the test requirements. Therefore, the main minerals (such as pyroxene, plagioclase, olivine and chromite) are purified from the Martian meteorite to ensure that they have high purity and are suitable for subsequent mixing and proportioning. Through physical separation methods, such as magnetic separation and flotation separation, the mineral monomers are purified, impurities are removed, and the target single mineral is obtained. For example, pyroxene is the electromagnetic part, which can be separated by an electromagnetic instrument or a small magnet. Pyroxene has strong magnetism, and the broken pieces are irregular particles, brown-yellow to brown-yellow-green, and have a glassy luster. Olivine is the electromagnetic part. Olivine is amorphous, and the broken pieces are rarely short columnar and thick plate-shaped. Most of them are irregular crystal forms with shell-like fractures and light yellow transparent minerals. Chromite (chrome spinel) is the electromagnetic part, and its appearance is like magnetite. It has strong magnetism, weaker than magnetite, stronger than pyroxene and olivine, black semi-metallic luster, high hardness, and the edges of the chromite broken blocks are brown-red, which is different from the black color of magnetite. The chromite amorphous in the sample is all broken blocks, and the surface of some particles is severely oxidized. Feldspar is a silicate mineral with no magnetic specific gravity and is translucent. It is enriched and purified by flotation during sorting, and enriched and distinguished by heavy liquid. Feldspar has a lighter specific gravity than quartz and a lower hardness than quartz. The surface of feldspar is oxidized and light red.

[0071] (2) X-ray diffraction (XRD), mineral crystal form: The selected target single mineral is placed on a zero-background sample table (to avoid interference from the base peaks) and XRD test is performed. The minimum test spot of micro-area XRD is 0.3 mm, so the target single mineral for sorting and purification only needs to be spread out more than 0.3 mm. The schematic diagram of the target single mineral focus is shown in Figure 7 For single minerals from the Earth, the amount is sufficient, so it can be directly ground and spread on the sample table for conventional XRD testing. Compare the XRD consistency of the target single mineral with that of the Earth single mineral, see the example Figure 8 .

[0072] (3) X-ray fluorescence (XRF) analysis to further confirm the overall chemical composition of the minerals: XRF elemental analysis was performed on the target single minerals sorted from the Martian meteorites and the single minerals from the Earth to obtain the overall elemental composition. Here, the FoM index (Φ m ), the range is 0-1, the closer it is to 1, the higher the similarity is, and the calculation formula is:

[0073]

[0074] Among them, u i represents the mass fraction of element i in the target single mineral, v i represents the mass fraction of element i in a single mineral on Earth, and n represents the number of elements.

[0075] An example of the calculation process is shown in Table 1, ensuring that Φ m Greater than 0.85 to ensure high fidelity of single minerals used to synthesize Martian soil simulant.

[0076] Table 1

[0077]

[0078] 3. Preparation of Martian Soil Simulant

[0079] According to the composition of each mineral phase in the Martian meteorite, the ratio of the single mineral on Earth is determined, referring to Figure 4 The proportion of each mineral phase obtained in the experiment is used to represent the overall mineral composition. In this embodiment, the ratio of the main minerals pyroxene, plagioclase, olivine and chromite is 0.5:0.18:0.3:0.02, and the roller mill is used to grind until 80% of the particles pass through a 40-mesh sieve (because the actual Martian soil particle size range detected by the Viking-1 detector is 0-500 microns), and then mixed in proportion. The final Martian soil simulant obtained after mixing is subjected to XRF testing and compared with the total XRF of the Martian meteorite. The FoM of the Martian soil simulant is used to evaluate the overall chemical element similarity. The formula is:

[0080]

[0081] Among them, U j represents the mass fraction of element j in Martian meteorites, V j represents the mass fraction of element j in the Martian soil simulant, and N represents the number of elements.

[0082] Comparison of total element contents between Martian soil simulant and Martian meteorite and Φ M The calculation results are shown in Table 2. MThe ratio of Φ to Φ reaches 0.93, which proves that this ratio can ensure that the Martian soil simulant is similar to Martian soil in terms of mineralogy and geochemistry, and the preparation of the Martian soil simulant is completed. M If it is less than 0.9, it means that the proportion of single minerals needs to be adjusted (the type has been determined and the consistency of the composition has been verified, so the problem lies in the proportion). Check which elements have too large a difference in content. For example, if Fe and Mg are much larger than those in Martian meteorites, then the proportion of olivine needs to be reduced; if there is too much Ca, feldspar or pyroxene can be reduced.

[0083] Table 2

[0084]

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a single mineral Martian soil simulant based on Martian meteorites, characterized in that: The following steps are involved: Step S1: Perform micro-area analysis on Martian meteorites to select single earth minerals required for preparing Martian soil simulant; Step S2: purify the target single mineral from the Martian meteorite and compare and analyze it with the single mineral on Earth; Step S3: preparing a Martian soil simulant; Step S4: Conduct an overall fidelity assessment of the Martian soil simulant.

2. The method for preparing a single mineral Martian soil simulant according to claim 1, characterized in that: The step S1 specifically includes: Step S1-1: preparing a mineral thin section sample from a Martian meteorite; Step S1-2: Perform TIMA mineral composition analysis to determine the coarse categories and proportions of various Martian meteorite minerals in the Martian meteorite, and use Raman spectroscopy to further determine the fine categories of Martian meteorite minerals; Step S1-3: Select the corresponding single earth mineral according to the subcategories of Martian meteorite minerals; Step S1-4: Perform electron probe micro-area analysis on the Martian meteorite minerals and the single minerals on Earth respectively to determine whether the mineral sub-classifications of the two are consistent. If they are consistent, execute step S2; otherwise, return to step S1-3.

3. The method for preparing a single mineral Martian soil simulant according to claim 2, characterized in that: The step S2 specifically includes: Step S2-1: physically crushing the Martian meteorite and purifying the target single mineral using a physical separation method; Step S2-2: Perform XRD analysis on the target single mineral and the earth single mineral respectively to determine whether the crystal structures of the two are consistent. If they are consistent, execute step S2-3; otherwise, return to step S1-3; Step S2-3: Perform XRF analysis on the target single mineral and the earth single mineral respectively to obtain the overall elemental composition of the two, and calculate the FoM index of the earth single mineral. If the FoM index of the earth single mineral meets the requirements, execute step S3, otherwise, return to step S1-3.

4. The method for preparing a single mineral Martian soil simulant according to claim 3, characterized in that: The step S3 specifically includes: Step S3-1: Determine the proportion of each Earth single mineral in the Martian soil simulant according to the proportion of each Martian meteorite mineral obtained in step S1-2; Step S3-2: weighing each single earth mineral and grinding it; Step S3-3: Mix the single mineral particles of the Earth according to the proportion to obtain a Martian soil simulant.

5. The method for preparing a single mineral Martian soil simulant according to claim 4, characterized in that: The step S4 specifically includes: Step S4-1: performing XRF analysis on the Martian soil simulant to obtain the overall elemental composition; Step S4-2: Calculate the FoM index of the Martian soil simulant. If the FoM index of the Martian soil simulant meets the requirements, a high-fidelity Martian soil simulant is obtained. Otherwise, return to step S3-1.

6. The method for preparing a single mineral Martian soil simulant according to claim 2, characterized in that: The step S1-2 specifically includes: (1) Scan the mineral thin section sample based on scanning electron microscopy and energy dispersive X-ray spectroscopy to quickly obtain the elemental composition of each pixel point and present it in the form of a backscattered electron image. The backscattered images of each pixel point are spliced ​​to obtain the backscattered image of the cross section of the complete mineral thin section sample. The grayscale is converted into an RGB image to intuitively obtain the mineral phase composition and distribution characteristics of the entire mineral thin section sample, and thus determine the rough category and proportion of each Martian meteorite mineral in the Martian meteorite; (2) Based on the mineral phase composition and distribution characteristics in the backscattered electron image, the area of ​​each mineral phase is found under a light microscope, and a Raman spectrum mapping test is performed on each mineral phase area to obtain the Raman spectrum characteristics of each mineral phase, thereby determining the subcategories of Martian meteorite minerals.

7. The method for preparing a single mineral Martian soil simulant according to claim 6, characterized in that: The step S1-4 specifically includes: Perform electron probe microanalysis on each mineral phase region in the mineral thin section sample to obtain the end-member element composition of each mineral phase in the mineral thin section sample; perform electron probe microanalysis on the selected single earth mineral preparation to obtain the end-member element composition of the single earth mineral, and compare the two. If the end-member diagram of the single earth mineral falls within the range of the end-member diagram of the mineral phase in the mineral thin section sample, then the mineral subdivisions of the two are deemed to be consistent, and step S2 is executed; otherwise, return to step S1-3.

8. The method for preparing a single mineral Martian soil simulant according to claim 3, characterized in that: The criterion for judging whether the crystal structures of the two are consistent in step S2-2 is that the 2Theta angle difference corresponding to the three strongest peaks of the two is less than 1°.

9. The method for preparing a single mineral Martian soil simulant according to claim 8, characterized in that: The FoM index Φ of the single mineral of the earth in step S2-3 m The calculation is as follows: Among them, u i represents the mass fraction of element i in the target single mineral, v i represents the mass fraction of element i in a single mineral on Earth, and n represents the number of elements; The conditions for the FoM index of a single mineral on Earth to meet the requirements are: Φ m >0.

85.

10. The method for preparing a single mineral Martian soil simulant according to claim 5, characterized in that: The FoM index Φ of the Mars soil simulant in step S4-2 M The calculation is as follows: Among them, U j represents the mass fraction of element j in Martian meteorites, V j represents the mass fraction of element j in the Martian soil simulant, and N represents the number of elements; The conditions for the FoM index of Mars soil simulant to meet the requirements are: Φ M ≥0.9.

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