Simulated lunar soil for engineering and preparation process thereof

Abstract

The invention discloses simulated lunar soil for engineering and a preparation process thereof, the simulated lunar soil has a multilayer structure design, and comprises a basic mineral structure layer, a surface activity control layer and a simulated space environment effect layer. The basic mineral structure layer is prepared from modified olivine, titanium-rich basalt, rare earth doped plagioclase, calcium phosphate minerals, nano iron particles and vitreous minerals according to a specific proportion; the surface activity control layer adopts an atomic layer deposition technology to form a nano oxide layer on the surface of the mineral particles; the simulated space environment effect layer is formed through low-pressure helium ion bombardment and ultraviolet irradiation. The preparation process comprises the steps of intelligent graded crushing, mineral phase change control, surface modification and activation treatment, multi-parameter synchronous regulation and control and the like. The simulated lunar soil can be produced in a customized mode according to different lunar area characteristics, the matching degree with real lunar soil physical characteristics exceeds 90%, the ground testing precision of lunar exploration equipment is remarkably improved, and technical support is provided for lunar on-site resource utilization and lunar base construction.

Description

Technical Field

[0001] The present invention relates to the technical fields of materials science and aerospace engineering, and particularly to an artificial lunar soil for engineering and its preparation process. Background Art

[0002] The moon is the first stop for human exploration of space and an important base and supply station for future deep space exploration. In projects such as lunar exploration, lunar base construction, and lunar resource development, lunar soil, as the main engineering medium, its physical and chemical properties have an important impact on the design and testing of related engineering equipment. Due to the extremely scarce and difficult-to-obtain real lunar soil resources, the development of simulated materials with properties close to lunar soil has become one of the key technologies to support the development of lunar engineering.

[0003] In the prior art, artificial lunar soil is usually prepared by selecting materials on the earth with similar material compositions and properties to those on the lunar surface based on lunar return samples or remote sensing data. Chinese invention patent CN102288472B discloses an artificial lunar soil for engineering and its preparation process. This patent selects volcanic ash in the Jinchuan area of Huinan County, Jilin Province as the raw material for artificial lunar soil. The artificial lunar soil is composed of nine kinds of volcanic ash with particle sizes of 3 mesh, 4 mesh, 8 mesh, 10 mesh, 18 mesh, 40 mesh, 60 mesh, 160 mesh, and 200 mesh according to their respective weight percentages; its preparation process includes raw material selection, volcanic slag drying, coarse crushing and drying of volcanic slag, volcanic slag powder making, and finished product preparation processes; the preparation cycle and control indexes of this technology meet the requirements of artificial lunar soil for engineering.

[0004] However, the existing artificial lunar soil technology has the following deficiencies: Single mineral phase composition: The prior art mainly relies on natural mineral raw materials from a single source and it is difficult to accurately simulate the distribution and proportion of multiple mineral phases in lunar soil; Large differences in surface characteristics: Lunar soil has been exposed to the space environment for a long time, and there is a special activation layer on its surface. The prior art fails to effectively simulate these surface characteristics; Lack of space environment effects: Lunar soil has been exposed to solar wind, cosmic rays, and vacuum environment for a long time, forming special physical and chemical properties. The prior art lacks the simulation of these space environment effects; Insufficient customization ability: The characteristics of lunar soil in different lunar regions (such as lunar maria, highlands, KREEP regions) are significantly different. The prior art is difficult to be flexibly customized according to different regions or different test requirements.

[0005] The above deficiencies result in a limited matching degree between the existing artificial lunar soil and actual lunar soil in engineering applications, especially in high-precision tests, there are large deviations, affecting the reliability and effectiveness of test results. Therefore, it is of great significance to develop a new type of artificial lunar soil and its preparation process that can more accurately simulate the physical properties, chemical activity, and space environment effects of lunar soil. Summary of the Invention

[0006] For the above purposes, the present invention provides an engineering-simulated lunar soil and its preparation process.

[0007] A preparation method of an engineering-simulated lunar soil includes the following steps: (1) Prepare a basic mineral structure layer according to a proportion, and the basic mineral structure layer includes modified olivine, titanium-rich basalt, synthetic plagioclase, calcium phosphate mineral, nano-scale iron particles and vitreous minerals; (2) Use atomic layer deposition technology to form a surface activity control layer on the surface of the basic mineral particles in step (1), and the surface activity control layer includes a nano-scale oxide layer; (3) Carry out a simulated treatment of space environmental effects on the particles obtained in step (2) to form a simulated space environmental effect layer, and the simulated space environmental effect layer is formed by low-pressure helium ion bombardment treatment and ultraviolet irradiation process.

[0008] Furthermore, in the basic mineral structure layer, the mass percentage of modified olivine is 20-40%, the mass percentage of titanium-rich basalt is 15-30%, the mass percentage of synthetic plagioclase is 15-45%, the mass percentage of calcium phosphate mineral is 3-15%, the mass percentage of nano-scale iron particles is 2-7%, and the mass percentage of vitreous minerals is 5-10%.

[0009] Furthermore, the preparation of modified olivine in step (1) includes: crushing olivine raw materials, and after sieving, performing surface nano-structure modification in a plasma treatment device; the preparation of titanium-rich basalt includes: subjecting titanium-rich basalt ore to classified crushing and then rapidly heating and quenching in an electromagnetic induction heating furnace to form a micro-stress structure; the preparation of synthetic plagioclase includes: adjusting the lattice structure by doping rare earth elements.

[0010] Furthermore, the atomic layer deposition technology is selected from Al2O3 deposition, TiO2 deposition, Fe2O3 deposition or a combination thereof to form a composite nano-layer with a thickness of 2-10 nm; after deposition, the surface hydroxyl density and active site distribution are adjusted through a surface activity regulation process.

[0011] Furthermore, the low-pressure helium ion bombardment treatment is carried out in a 10⁻ 6 Pa vacuum environment, the helium ion energy is 1-3 keV, and the beam current density is 3-8 μA / cm²; the ultraviolet irradiation process uses an ultraviolet light source with a wavelength of 150-200 nm and irradiates in a 10⁻³ Pa vacuum environment for 48-120 hours.

[0012] Furthermore, the simulated lunar soil has a multi-layer structure, including a basic mineral structure layer, a surface activity control layer, and a simulated space environment effect layer; the internal friction angle of the simulated lunar soil is 32-38°, the cohesion is 0.8-1.5 kPa, and the bulk density is 1.5-1.9 g / cm³.

[0013] Furthermore, the particle size distribution of the simulated lunar soil is as follows: <50μm accounts for 10-20%, 50-100μm accounts for 25-35%, 100-300μm accounts for 35-45%, >300μm accounts for 10-20%; the surface active site density of the simulated lunar soil is 3.0×10¹ 4 -5.0×10¹ 4 sites / cm².

[0014] Furthermore, the simulated lunar soil is divided into three basic types: highland type, mare type, and KREEP region type; among them, the SiO2 content of the highland type simulated lunar soil is 44-46%, and the Al2O3 content is 23-25%; the SiO2 content of the mare type simulated lunar soil is 40-42%, and the FeO content is 15-17%; the SiO2 content of the KREEP region type simulated lunar soil is 43-45%, the K2O content is 1.0-1.5%, the P2O5 content is 2.0-2.5%, and the total rare earth element content is 0.8-1.0%.

[0015] Furthermore, the simulated lunar soil is functionally modified, selected from: enhancing the electrical conductivity by adding 5-10% carbon nanotubes, or enhancing the thermal stability by adding 3-5% boron nitride nanosheets, or regulating the magnetic response by adding 1-3% superparamagnetic Fe3O4 nanoparticles.

[0016] Furthermore, the application of the engineering simulated lunar soil in the ground test of lunar exploration equipment, the research and development of lunar in-situ resource utilization technology, and the research of lunar base construction technology.

[0017] The beneficial effects of the present invention: The engineering simulated lunar soil provided by the present invention and its preparation process adopt a multi-level design method, and are constructed through the combination of a basic mineral structure layer, a surface activity control layer, and a simulated space environment effect layer. Combined with innovative preparation technologies such as atomic layer deposition, low-pressure helium ion bombardment, and ultraviolet irradiation, etc., the accurate simulation of the physical properties, chemical activity, and space environment effects of lunar soil has been successfully achieved. Compared with traditional technologies, this simulated lunar soil has significant improvements in terms of physical property matching, chemical composition consistency, and surface activity simulation. Its key parameters such as internal friction angle, cohesion, and bulk density are highly consistent with actual lunar soil. At the same time, it has good customization ability and can be adjusted specifically according to different lunar region characteristics or test requirements. Application verification shows that this simulated lunar soil can accurately reflect the engineering characteristics under the lunar surface environment during the detection equipment test, and the test accuracy is improved by about 40%, significantly enhancing the reliability and effectiveness of ground tests, and providing important technical support for fields such as lunar exploration, in-situ resource utilization, and lunar base construction. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those 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.

[0019] Figure 1 Schematic diagram of the preparation process flow of the engineering simulated lunar soil of the present invention; Figure 2 Schematic diagram of the comparison of the components and characteristics of different types of simulated lunar soil of the present invention. Detailed Embodiments

[0020] The following will describe the present invention in detail with reference to the drawings and specific embodiments. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; and the drawings part is only for more specific description of the embodiments, and is not intended to specifically limit the present invention.

[0021] It should be pointed out that in the specification, it is mentioned that "an embodiment", "embodiment", "exemplary embodiment", "some embodiments", etc. indicate that the described embodiment may include specific features, structures, or characteristics, but not necessarily every embodiment includes the specific feature, structure, or characteristic. In addition, when combining an embodiment to describe a specific feature, structure, or characteristic, implementing such a feature, structure, or characteristic in combination with other embodiments (whether explicitly described or not) should be within the knowledge scope of those skilled in the relevant art.

[0022] Generally, terms can be understood at least in part from their use in context. For example, depending at least in part on the context, the term "one or more" as used herein can be used to describe any feature, structure, or property in a singular sense, or can be used to describe a combination of features, structures, or properties in a plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey a set of exclusive factors, but rather can alternatively, depending at least in part on the context, allow for the existence of other factors that are not necessarily explicitly described.

[0023] Embodiment 1: Preparation of the basic mineral structure layer Raw material preparation Olivine raw material: High-purity olivine minerals (purity ≥ 98%) are selected, with a particle size range of 0.5 - 2 mm.

[0024] Titanium-rich basalt: Basalt ore with a TiO2 content of 6 - 10% is selected, with an initial particle size < 5 mm.

[0025] Plagioclase raw material: Anorthite (cation ratio Ca:Na:K = 70:25:5) is selected, with an initial particle size < 3 mm.

[0026] Calcium phosphate mineral: Hydroxyapatite is selected, with a purity ≥ 95% and an initial particle size < 1 mm.

[0027] Iron powder: High-purity reduced iron powder (purity ≥ 99.5%) is selected, with an initial particle size < 50 μm.

[0028] Vitreous mineral: Volcanic glass or synthetic aluminosilicate glass is selected.

[0029] Preparation process of modified olivine The olivine raw material is placed in a planetary ball mill for preliminary crushing, with a ball-to-material ratio of 10:1, a rotation speed of 300 rpm, and a crushing time of 4 hours.

[0030] The crushed olivine powder is sieved through a 200-mesh sieve, and the undersize is collected.

[0031] The undersize is placed in a plasma treatment device, and under an argon atmosphere (argon purity 99.999%), the power is set to 800 W, and the treatment time is 30 minutes.

[0032] The plasma-treated olivine powder is placed in a vacuum drying oven at a temperature of 120°C, a vacuum degree of 0.01 Pa, and a drying time of 12 hours.

[0033] Preparation of angular particles of titanium-rich basalt The titanium-rich basalt ore is placed in a jaw crusher for preliminary crushing, with an output particle size < 2 mm.

[0034] Place the crushed material in an impact crusher, set the rotation speed to 1200 rpm, and perform secondary crushing.

[0035] Use an asymmetric vibration screening system for classification, and collect materials of 30 - 100 μm, 100 - 300 μm, and >300 μm respectively.

[0036] Place the classified material in an electromagnetic induction heating furnace, quickly heat it to 1100 °C under nitrogen protection, keep it warm for 15 minutes, and then rapidly cool it to room temperature to form a micro - stress structure.

[0037] Rare - earth element doping of synthetic plagioclase Calcine the plagioclase raw material in a high - temperature furnace with an alternating redox atmosphere at a temperature of 1200 °C for 2 hours.

[0038] Crush the calcined plagioclase to an average particle size of <100 μm.

[0039] Prepare a rare - earth element solution by dissolving La2O3, Ce2O3, and Y2O3 in a nitric acid solution according to a molar ratio of 2:2:1.

[0040] Use the impregnation method to mix the rare - earth element solution with the plagioclase powder, with a liquid - to - solid ratio of 2:1 and a stirring time of 2 hours.

[0041] Dry the impregnated material at 80 °C, and then calcine it at 1150 °C for 4 hours in an argon atmosphere to form rare - earth - doped plagioclase.

[0042] Preparation of nano - scale iron particles Adopt the liquid - phase reduction method to react FeCl3 solution (0.1 mol / L) with NaBH4 solution (0.3 mol / L) under nitrogen protection.

[0043] Control the reaction temperature at 5 °C, the dropping rate at 2 mL / min, and the stirring rate at 500 rpm.

[0044] After the reaction is completed, collect the nano - iron particles by magnetic separation.

[0045] Wash with anhydrous ethanol and deionized water alternately 3 times.

[0046] Dry in a vacuum environment (0.001 Pa) at 50 °C for 12 hours.

[0047] Store the dried nano - iron particles under argon protection.

[0048] Embodiment 2: Preparation of the surface - active control layer Atomic layer deposition (ALD) process parameters TMA (trimethylaluminum) and H2O were selected as precursors for atomic layer deposition of Al2O3 at 150 °C.

[0049] The pressure in the reaction chamber was controlled at 10 Pa.

[0050] The pulse time of TMA was 0.5 s, the purge time with N2 was 5 s, the pulse time of H2O was 0.5 s, and the purge time with N2 was 5 s.

[0051] After 30 cycles, an Al2O3 layer with a thickness of about 3 nm was formed.

[0052] On the Al2O3 layer, TTIP (tetraisopropyl orthotitanate) and H2O were used as precursors for atomic layer deposition of TiO2 at 200 °C.

[0053] The pulse time of TTIP was 1 s, the purge time with N2 was 10 s, the pulse time of H2O was 0.5 s, and the purge time with N2 was 10 s.

[0054] After 50 cycles, a TiO2 layer with a thickness of about 5 nm was formed.

[0055] Surface activity regulation process The ALD-treated particles were immersed in a 1% hydrofluoric acid solution for 30 s to form surface hydroxyl groups.

[0056] They were washed with deionized water until neutral and then vacuum-dried at 60 °C for 4 h.

[0057] The treated particles were immersed in a 0.01 mol / L ethanol solution of silane coupling agent (3-aminopropyltriethoxysilane) for 2 h.

[0058] They were filtered and washed 3 times with absolute ethanol and dried at 80 °C for 6 h.

[0059] The modified particles were heat-treated at 350 °C for 1 h under nitrogen protection to form a stable surface activity layer.

[0060] Embodiment 3: Preparation of simulated space environment effect layer Helium ion bombardment treatment process The treated simulated lunar soil was placed in an ultra-high vacuum ion bombardment device, and the vacuum degree reached 10⁻ 6 Pa.

[0061] Helium ion source parameter settings: ion energy 2 keV, beam current density 5 μA / cm².

[0062] Scanning bombardment was adopted to ensure that the sample surface was uniformly treated.

[0063] The bombardment time was adjusted according to the simulated depth, and the standard process was set to 120 minutes.

[0064] After bombardment, transfer the sample to a sealed container without breaking the vacuum.

[0065] Ultraviolet irradiation process Use a high-energy ultraviolet light source (wavelength mainly distributed in 150 - 200 nm) with a power density of 50 mW / cm².

[0066] Spread the sample evenly on a quartz carrier, ensuring that the thickness does not exceed 2 mm.

[0067] Irradiate in a vacuum environment of 10⁻³ Pa, with the temperature controlled at -20°C.

[0068] The irradiation time is 72 hours. During this period, turn the sample every 12 hours to ensure uniform irradiation.

[0069] After irradiation, transfer and store it in a sealed manner under nitrogen protection.

[0070] Example 1: Preparation of highland-type simulated lunar soil Formulation design Design the highland-type simulated lunar soil formula according to weight percentage: Modified olivine: 20% Ti-rich basalt: 15% Rare earth-doped plagioclase: 45% Calcium phosphate mineral: 10% Nano iron particles: 2% Vitreous mineral: 8% Preparation steps Weigh and mix the raw material components according to the designed formula evenly.

[0071] Use a three-dimensional mixer (rotation speed 30 rpm) to mix for 2 hours to ensure uniform distribution of each component.

[0072] Classify the mixture to ensure that the particle size distribution is: <50μm (10%), 50 - 100μm (25%), 100 - 300μm (45%), >300μm (20%).

[0073] Adopt ALD technology for surface modification to deposit a composite nano-layer of Al2O3 and TiO2.

[0074] Perform helium ion bombardment and ultraviolet irradiation treatment to simulate the space environment effect.

[0075] Store it in a sealed manner using a special airtight polymer material container under inert gas protection.

[0076] Performance test results Physical properties: Bulk density: 1.53 g / cm³ Particle morphology: High angularity, surface roughness score 8.7 / 10 Thermal conductivity: 0.8 W / (m·K) Specific surface area: 2.8 m² / g Porosity: 45% Chemical properties: Main element content (wt%): SiO2 45.2%, Al2O3 24.6%, CaO 15.3%, MgO 6.1%, FeO 4.2%, TiO2 2.1%, others 2.5%.

[0077] Surface active site density: 3.6×10¹ 4 sites / cm² pH value (aqueous extract): 8.3 Mechanical properties: Internal friction angle: 35.2° Cohesion: 0.9 kPa Compaction coefficient: 0.31 Example 2: Preparation of mare-type simulated lunar soil Formulation design Design the mare-type simulated lunar soil formulation according to weight percentage: Modified olivine: 40% Ti-rich basalt: 30% Rare earth-doped plagioclase: 15% Calcium phosphate mineral: 3% Nanoscale iron particles: 7% Vitreous mineral: 5% Preparation steps: Weigh and mix the raw materials of each component evenly according to the designed formulation.

[0078] Mix using a three-dimensional mixer (rotation speed 40 rpm) for 2.5 hours.

[0079] Perform ultrasonic-assisted dispersion treatment on the mixture, with a power of 200 W and a treatment time of 30 minutes.

[0080] Perform classification treatment on the mixture to ensure that the particle size distribution is: <50 μm (20%), 50 - 100 μm (35%), 100 - 300 μm (35%), >300 μm (10%).

[0081] Adopt ALD technology for surface modification to deposit a composite nano-layer of Fe2O3 and TiO2.

[0082] Perform helium ion bombardment treatment (intensity increased by 20%) and extended ultraviolet irradiation (96 hours).

[0083] Conduct 5 temperature cycles (-150°C to +120°C) in a vacuum environment (-20°C) to simulate the lunar day-night temperature difference effect.

[0084] Performance test results Physical properties: Bulk density: 1.86 g / cm³ Particle morphology: Medium angularity, surface roughness score 6.8 / 10 Thermal conductivity: 1.2 W / (m·K) Specific surface area: 3.4 m² / g Porosity: 38% Chemical properties: Main element content (wt%): SiO2 41.6%, Al2O3 12.8%, CaO 10.2%, MgO 13.5%, FeO 16.4%, TiO2 4.3%, others 1.2%.

[0085] Surface active site density: 4.2×10¹ 4 sites / cm² pH value (aqueous extract): 7.9; Mechanical properties: Internal friction angle: 32.8° Cohesion: 1.2 kPa Compaction coefficient: 0.38 Example 3: Preparation of KREEP region simulated lunar soil Formulation design; Design the KREEP region simulated lunar soil formulation according to weight percentage: Modified olivine: 25% Ti-rich basalt: 20% Rare earth doped plagioclase: 30% Calcium phosphate mineral: 15% Nanoscale iron particles: 3% Vitreous mineral: 7% Special additive components Rare earth element enriched minerals: Thorite (ThO2) 0.3%, Monazite [(Ce, La, Nd, Th)PO4] 0.5%; Radioactive element simulated additive: Non-radioactive isotope substitute, Zircon (ZrSiO4) 0.4% as a substitute for U.

[0086] Preparation steps Conventional components are prepared by standard processes, and special additive components are processed by ultrafine grinding to a particle size <10 μm.

[0087] The rare earth element enrichment layer is prepared by the sol-gel method. The specific steps are as follows: Prepare an aqueous solution containing rare earth nitrates (total concentration 0.1 mol / L); Add tetraethyl orthosilicate (TEOS) as the SiO2 precursor; Dropwise add NH3·H2O to adjust the pH to 8.5 to form a gel; After the gel is aged for 24 hours, it is dried at 60 °C; Calcine at 850 °C for 2 hours in an argon atmosphere.

[0088] Mix the calcined product with the main components and use a mixer with a shearing effect to mix for 3 hours.

[0089] Adjust the particle size distribution to: <50 μm (15%), 50 - 100 μm (30%), 100 - 300 μm (40%), >300 μm (15%).

[0090] Adopt the multi-layer ALD technology to deposit Al2O3 (2 nm), TiO2 (3 nm) and Fe2O3 (1 nm) in sequence.

[0091] Carry out enhanced space environment simulation treatment: Increase the helium ion bombardment intensity by 50%; Prolong the ultraviolet irradiation time to 120 hours; Expand the temperature cycle range to -180 °C to +150 °C, with a total of 10 cycles.

[0092] Performance test results Physical properties: Bulk density: 1.67 g / cm³ Particle morphology: High angularity, surface roughness score 8.9 / 10 Thermal conductivity: 0.95 W / (m·K) Specific surface area: 3.7 m² / g Porosity: 42% Chemical properties: Main element content (wt%): SiO2 43.8%, Al2O3 20.2%, CaO 12.8%, MgO 9.3%, FeO 5.8%, TiO2 3.1%, P2O5 2.4%, K2O 1.2%, total rare earth element 0.9%, others 0.5%; Surface active site density: 4.8×10¹ 4 sites / cm²; pH value (aqueous extract): 8.1.

[0093] Special properties: Thermoluminescence property: The matching degree with the thermoluminescence curve of lunar return samples reaches 85%; Magnetic property: The saturation magnetization intensity is 12.5 Am² / kg, similar to lunar samples.

[0094] Quality control and verification methods Verification of physical properties Analysis of particle morphology: Morphology observation is carried out using a field emission scanning electron microscope (FE-SEM); Image analysis software is used to calculate the shape factor, angularity and roughness; Verification is carried out by comparing with the images of lunar soil samples from Apollo missions and Chang'e missions.

[0095] Analysis of particle size distribution: It is measured using a laser particle size analyzer; For each batch, ≥5 sampling points are taken, and the average value is obtained by measuring 3 times; The deviation from the designed distribution is required to be <5%.

[0096] Determination of bulk density: The loose density and tapped density are measured respectively by the standard loose filling method and the tapping method; The Haney index is calculated to evaluate the fluidity; For each batch, the measurement is carried out ≥3 times, and the relative standard deviation is <3%.

[0097] Verification of chemical composition Analysis of main elements: The major elements are analyzed by X-ray fluorescence spectroscopy (XRF); The trace elements are analyzed by inductively coupled plasma mass spectrometry (ICP-MS); For each batch, the measurement is carried out ≥2 times, and the relative standard deviation is <5%.

[0098] Analysis of mineral phases: The crystal phase composition is analyzed by X-ray diffraction (XRD); The characteristic mineral phases are analyzed by Raman spectroscopy; Comparison is made with the standard spectra, and the matching degree requirement is >90%.

[0099] Analysis of surface properties: The valence states of surface elements are analyzed by X-ray photoelectron spectroscopy (XPS); The specific surface area and pore size distribution are determined by the low-temperature N2 adsorption-desorption method; The surface hydrophilicity / hydrophobicity is evaluated by contact angle measurement.

[0100] Verification of mechanical properties Determination of internal friction angle and cohesion: Measure under different normal stresses using a direct shear apparatus; Measure separately under a simulated vacuum environment (10⁻³ Pa) and an atmospheric pressure environment; Compare with the lunar soil values reported in the literature, with a deviation requirement of < 15%.

[0101] Determination of compaction performance: Determine the optimum moisture content and the maximum dry density using a standard compaction test; Evaluate the compaction characteristics through the load-settlement curve; Determine the compaction coefficient under a simulated lunar surface gravity environment.

[0102] Verification of space environment effects Radiation stability test: Simulate the radiation effect using an electron beam accelerator; Set the dose to 10 4 ~10 6 Gy; Determine the changes in physical and chemical properties before and after radiation.

[0103] Vacuum stability test: Maintain in an environment of 10⁻ 5 Pa for 30 days; Determine the changes in surface active sites; Evaluate the gas release characteristics.

[0104] Storage and usage suggestions Storage conditions: Use a special multi-layer isolation packaging, with an inner electrostatic protection layer Suggested storage temperature: 18 - 25 °C Control the relative humidity at < 30% Store away from light and keep away from strong magnetic field environments Pre-treatment before use: It is recommended to degas under vacuum at 80 °C for 24 hours before use Perform pre-treatment according to ISO standards before analysis and testing Check the uniformity before use after long-term storage Expiry date: Under standard storage conditions, the physical property stability period is ≥ 3 years The surface activity property stability period is ≥ 1 year After exceeding the expiry date, it is recommended to reactivate Precautions for engineering applications: When contacting with equipment, it is recommended to take anti-static measures; Avoid long-term exposure to a humid environment during the treatment process; For large-scale applications, small-batch pre-tests are recommended.

[0105] Example 4: Preparation of Simulated Lunar Soil at the Impact Crater Edge Formulation Design Design the simulated lunar soil formulation at the impact crater edge by weight percentage: Modified olivine: 30% Ti-rich basalt: 25% Rare earth-doped plagioclase: 25% Calcium phosphate mineral: 5% Nano iron particles: 5% Glassy mineral: 10% Special Process Treatment Impact metamorphism simulation process: Place the basic mineral mixture in a special high-pressure pneumatic impact device; Set the impact pressure to 15 GPa; The impact duration < 10 microseconds; Repeat the impact 3 times, adjusting the sample position at each interval.

[0106] Melt injection process: Place part (about 20%) of the mineral mixture in a plasma melting device; Control the temperature at 1800 °C; The melting time is 10 seconds; Inject the melt onto a cooling table (temperature -50 °C) for rapid cooling; Form amorphous glassy particles.

[0107] Composite assembly process: Mix the impact-metamorphosed mineral particles (70%) with the melt-injected glassy particles (30%); Use ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) as the bonding medium; Vacuum treat at 80 °C for 2 hours to form a composite structure.

[0108] Performance Test Results Physical properties: Bulk density: 1.72 g / cm³; Particle morphology: Extremely high angularity, surface roughness score 9.3 / 10; Thermal conductivity: 0.65 W / (m·K); Specific surface area: 4.2 m² / g; Void fraction: 48%.

[0109] Chemical properties: Main element content (wt%): SiO2 44.3%, Al2O3 18.7%, CaO 11.6%, MgO 10.5%, FeO 8.2%, TiO2 3.8%, Others 2.9%; Amorphous content: 26.5%; Shock metamorphism index: Standard shock metamorphism index (SMI) 7.2, similar to the lunar soil at the edge of typical impact craters.

[0110] Mechanical properties: Internal friction angle: 37.6°; Cohesion: 1.4 kPa; Compaction coefficient: 0.28; Shear strength is 20% higher than that of mare-type simulated lunar soil.

[0111] Example 5: Functional modification and customized optimization of simulated lunar soil Functional modification scheme Enhanced electrical conductivity: Add 5% carbon nanotubes (CNT) to the standard mare-type simulated lunar soil; CNT pretreatment: First, treat with a mixed acid solution of H2SO4 / HNO3 (3:1) for 4 hours, and then neutralize with ammonia water to pH = 7; Use a surfactant (sodium dodecyl sulfate, 0.5%) to assist in the dispersion of CNT; After functional treatment, the volume resistivity decreases from 10¹ 0 Ω·cm to 10 5 Ω·cm.

[0112] Enhanced thermal stability: Add 3% boron nitride nanosheets to the highland-type simulated lunar soil; The surface of boron nitride nanosheets is modified by a silane coupling agent (KH-550); After treatment, the thermal conductivity is increased to 1.5 W / (m·K); The coefficient of thermal expansion is reduced by 25%.

[0113] Magnetic response regulation: Add 1% superparamagnetic Fe3O4 nanoparticles (particle size 15 nm) to the standard lunar soil; Prepare Fe3O4 nanoparticles by acoustic wave-assisted in-situ synthesis method; After treatment, the saturation magnetization intensity reaches 4.5 emu / g; The responsiveness of the simulated lunar soil to an external magnetic field is enhanced by 8 times.

[0114] Customized optimization process Optimization for the detector landing test: Enhanced edge angle factor: Extend the ball milling time by 50% to increase the sharpness of the edges and corners.

[0115] Precise control of the friction coefficient: Achieve precise control of the internal friction angle within ±1° through the control of the surface hydroxyl density.

[0116] Result: The deviation between the test data of the landing buffer system and the actual lunar surface data is reduced to 8.5%.

[0117] Optimization for the testing of drilling equipment: Simulation of the layered structure: Design a multi-layer compacted structure to simulate the change in the compactness of lunar soil at different depths; The first layer (0 - 30 cm): Standard loose-packed lunar soil with a density of 1.5 g / cm³; The second layer (30 - 60 cm): Compacted lunar soil with a density of 1.8 g / cm³; The third layer (60 - 100 cm): A mixed layer of highly compacted lunar soil and simulated rock with a density of 2.2 g / cm³; Result: The coincidence degree between the resistance curve during drilling and the actual drilling data of the Chang'e probe reaches 86%.

[0118] Optimization for the testing of in-situ resource utilization (ISRU): Regulation of oxygen content: Precisely control the proportion of oxygen-containing minerals to be consistent with the extractable oxygen content in lunar soil; Optimization of the distribution of metal elements: Simulate the content and distribution of extractable metal elements such as Fe, Ti, and Al in lunar soil to match the actual lunar soil; Result: The test deviation of oxygen extraction efficiency is <5%, and the test deviation of metallurgical extraction of metals is <7%.

[0119] Example 6: Large-scale production process Production line design Production capacity specifications: Daily production capacity: 300 kg for the standard model and 100 kg for the customized model Batch size: 50 kg / batch Floor area of the production line: 800 m² Configuration of key equipment: Multi-stage precision crushing system: Planetary ball mill (5 units), impact crusher (3 units) Intelligent classification system: Airflow classifier (2 units), screening system (4 units) Surface modification equipment: ALD reactor (large, 2 units; medium, 3 units) Space environment simulation equipment: Ion bombardment chamber (2 units), ultraviolet light irradiation system (4 units) Quality control system: Online particle detector, element analyzer, X-ray diffractometer Automation control system: Multi-parameter real-time monitoring system: Real-time collection of parameters such as temperature, pressure, air flow, energy consumption, etc. Quality traceability system: Each batch of products is marked with a QR code, and all process production parameters are recorded. Digital twin system: Establish a digital model of the production line for process optimization and prediction. Optimization of batch production process parameters Raw material pretreatment process: Raw material pre-screening: Spectral analysis is used to screen raw materials with a mineral purity > 95%. Pre-drying: Vacuum drying oven, 80°C, 12 hours Pre-crushing: Initially crushed to < 5mm to improve the subsequent crushing efficiency. Optimization of the crushing process: Staged crushing: Coarse crushing (5mm → 1mm) → Medium crushing (1mm → 0.3mm) → Fine crushing (< 0.1mm) Energy consumption optimization: The energy consumption is reduced by 32% compared with the traditional process. Selection of crushing medium: Zirconia balls are used as the grinding medium to avoid iron contamination. Surface modification batch treatment: Bed design of large-scale ALD equipment: Fluidized bed structure to ensure uniform contact of particles with reaction gases. Optimization of cycle parameters: Reduce the purge time between pulses to improve production efficiency. Result: The processing capacity is increased by 3 times, and the cost is reduced by 40%. Quality control strategy: Key point detection: Raw materials entering the factory → After crushing → After surface modification → After environmental effect treatment → Finished products Sample random inspection ratio: 5% Full inspection items: Particle size distribution, bulk density Random inspection items: Elemental composition, mineral phase, surface characteristics, mechanical properties Cost-benefit analysis Cost composition: Raw material cost: 28% Energy cost: 22% Equipment depreciation: 25% Labor cost: 15% Others (packaging, transportation, etc.): 10% Unit cost: Standard highland-type simulated lunar soil: 4800 yuan / kg Standard mare-type simulated lunar soil: 5200 yuan / kg Customized simulated lunar soil: 8000 - 12000 yuan / kg (depending on customization requirements) Economic benefit analysis: Compared with traditional simulated lunar soil (performance index matching degree < 70%): The price is increased by about 25% The performance matching degree is increased to > 90% The comprehensive cost performance is increased by about 65% The simulated lunar soil for engineering and its preparation process proposed by the present invention successfully solve the deficiencies of traditional simulated lunar soil in terms of physical properties, chemical activity and simulation of space environment effects through a multi-level design method and an innovative preparation process. The developed simulated lunar soil is highly consistent with the actual lunar soil in terms of physical properties, chemical composition and mineral phase distribution. Through various engineering application verifications, it can accurately reflect the engineering properties under the lunar surface environment.

[0120] This technology can not only be used for the ground testing of various lunar exploration equipment, but also support the research and development of lunar in-situ resource utilization technology and the research on the construction of lunar bases, which is of great significance for promoting the development of deep space exploration technology and the development of lunar resources.

[0121] The present invention covers any substitutions, modifications, equivalent methods and solutions made on the essence and scope of the present invention. In order to enable the public to have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention. However, those skilled in the art can fully understand the present invention without the description of these details. In addition, well-known methods, processes, procedures, components and circuits are not described in detail to avoid unnecessary confusion to the essence of the present invention.

[0122] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of simulated lunar soil for engineering purposes, characterized in that, It includes the following steps: (1) Prepare a basic mineral structure layer in proportion, and the basic mineral structure layer includes modified olivine, titanium-rich basalt, synthetic plagioclase, calcium phosphate mineral, nano-scale iron particles and vitreous minerals; (2) Use atomic layer deposition technology to form a surface activity control layer on the surface of the basic mineral particles in step (1), and the surface activity control layer includes a nano-scale oxide layer; (3) Carry out a simulated treatment of space environmental effects on the particles obtained in step (2) to form a simulated space environmental effect layer, and the simulated space environmental effect layer is formed by low-pressure helium ion bombardment treatment and ultraviolet irradiation process.

2. The preparation method according to claim 1, characterized in that, In the basic mineral structure layer, the mass percentage of modified olivine is 20-40%, the mass percentage of titanium-rich basalt is 15-30%, the mass percentage of synthetic plagioclase is 15-45%, the mass percentage of calcium phosphate mineral is 3-15%, the mass percentage of nano-scale iron particles is 2-7%, and the mass percentage of vitreous minerals is 5-10%.

3. The preparation method according to claim 1, characterized in that, The preparation of modified olivine in step (1) includes: crushing olivine raw materials, and after sieving, carrying out surface nano-structure modification in a plasma treatment device; the preparation of titanium-rich basalt includes: grading and crushing titanium-rich basalt ore, and then rapidly heating and quenching in an electromagnetic induction heating furnace to form a microscopic stress structure; the preparation of synthetic plagioclase includes: adjusting the lattice structure by doping rare earth elements.

4. The preparation method according to claim 1, wherein, In step (2), the atomic layer deposition technology is selected from Al2O3 deposition, TiO2 deposition, Fe2O3 deposition or a combination thereof to form a composite nano-layer with a thickness of 2-10 nm; after deposition, adjust the surface hydroxyl density and active site distribution through a surface activity regulation process.

5. The preparation method according to claim 1, characterized in that, In step (3), the low-pressure helium ion bombardment treatment is carried out in a vacuum environment of 10⁻ 6 Pa, the energy of the helium ions is 1-3 keV, and the beam current density is 3-8 μA / cm²; for the ultraviolet irradiation process, an ultraviolet light source with a wavelength of 150-200 nm is used, and irradiation is carried out in a vacuum environment of 10⁻³ Pa for 48-120 hours.

6. An engineering-simulated lunar soil prepared by the preparation method according to any one of claims 1-5, characterized in that, The simulated lunar soil has a multi-layer structure, including a basic mineral structure layer, a surface activity control layer and a simulated space environmental effect layer; the internal friction angle of the simulated lunar soil is 32-38°, the cohesion is 0.8-1.5 kPa, and the bulk density is 1.5-1.9 g / cm³.

7. The simulated lunar soil for engineering use according to claim 6, characterized in that, The particle size distribution of the simulated lunar soil is as follows: <50μm accounts for 10 - 20%, 50 - 100μm accounts for 25 - 35%, 100 - 300μm accounts for 35 - 45%, >300μm accounts for 10 - 20%; the density of surface active sites of the simulated lunar soil is 3.0×10¹ 4 -5.0×10¹ 4 sites / cm².

8. The simulated lunar soil for engineering use according to claim 6, characterized in that, The simulated lunar soil is divided into three basic types: highland type, mare type and KREEP region type; among them, the SiO2 content of the highland type simulated lunar soil is 44-46%, and the Al2O3 content is 23-25%; the SiO2 content of the mare type simulated lunar soil is 40-42%, and the FeO content is 15-17%; the SiO2 content of the KREEP region type simulated lunar soil is 43-45%, the K2O content is 1.0-1.5%, the P2O5 content is 2.0-2.5%, and the total rare earth element content is 0.8-1.0%.

9. The simulated lunar soil for engineering use according to claim 6, wherein The simulated lunar soil is functionally modified, selected from: enhancing the electrical conductivity by adding 5-10% carbon nanotubes, or enhancing the thermal stability by adding 3-5% boron nitride nanosheets, or regulating the magnetic response by adding 1-3% superparamagnetic Fe3O4 nanoparticles.

10. Application of the engineering simulated lunar soil according to any one of claims 6-9 in ground testing of lunar exploration equipment, research and development of lunar in-situ resource utilization technology, and research on lunar base construction technology.

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