A method for preparing simulated lunar soil suitable for resource utilization

Abstract

The present invention relates to a method for preparing simulated lunar soil suitable for resource utilization, comprising the following steps: S1, crushing a basalt sample and subjecting it to a primary magnetic separation to obtain a primary magnetic separation sample; S2, grinding the primary magnetic separation sample and subjecting the ground primary magnetic separation sample to a heating hydrogen reduction reaction to obtain a hydrogen reduction product; S3, subjecting the hydrogen reduction product to a secondary magnetic separation, drying the iron-removed sample to obtain a secondary magnetic separation sample for later use; S4, mixing ilmenite powder with a reducing gas to react to obtain an ilmenite mixture containing elemental iron, followed by sintering and pulverizing to obtain ilmenite particles; S5, mixing the secondary magnetic separation sample obtained in S4 with the ilmenite particles obtained in S5 according to a preset mass ratio, pressing the mixture into tablets, and sintering the mixture in an inert atmosphere to obtain a mixed sintered sample; S6, crushing the mixed sintered sample to obtain simulated lunar soil particles. The simulated lunar soil of the present invention conforms to the actual symbiotic composition patterns of lunar soil minerals.

Description

Technical Field

[0001] The present invention relates to the field of related technical fields such as the preparation of simulated lunar soil, and in particular to a method for preparing simulated lunar soil suitable for resource utilization. Background Art

[0002] Existing simulated lunar soil is primarily used for engineering research applications, primarily in geotechnical engineering, electrostatic migration, and 3D construction. Simulated lunar soil samples for mineral beneficiation and smelting have yet to be developed. Utilization of lunar soil minerals focuses on ilmenite. Research into ilmenite separation, titanium and iron smelting, and hydrogen reduction water production presents a series of key technical challenges, requiring a large number of simulated lunar soil samples for in-depth theoretical research and destructive testing. These samples should possess typical lunar soil physicochemical characteristics and be free of interfering components from mineral separation and smelting.

[0003] The existing simulated lunar soil is mostly made from basalt or volcanic ash that is widely distributed on the earth. The materials ejected from the surface are affected by the earth's surface environment and undergo varying degrees of oxidation, generating iron oxides, such as a small amount of hematite and magnetite. At the same time, some minerals are altered by the combined action of water and oxygen in the environment to form water-containing minerals, such as mica, hornblende, zeolite, montmorillonite and other minerals. Lunar regolith contains extremely low levels of magnetite, only a few parts per thousand, which has a limited impact on the regolith's magnetic properties. However, the presence of minor magnetite phases in existing simulated lunar regolith significantly influences its magnetic susceptibility, impacting the effectiveness of ground-based electromagnetic beneficiation simulations. Furthermore, the widespread presence of hydrous alteration minerals (mica, hornblende, montmorillonite, zeolite, etc.) in terrestrial basalts can affect the kinetics of metallurgical reduction processes of metal oxides (ilmenite). The water produced by these alteration minerals, as well as the water released by these hydrous minerals during high-temperature processes, directly interferes with the determination of the water content of the reaction products, hindering the study and evaluation of chemical reaction kinetics. Interfering minerals such as hematite and magnetite also participate in the reduction process, affecting the measurement of the degree of iron reduction. Furthermore, studies have shown that lunar regolith contains a small amount of elemental iron, formed by space weathering. This iron is widely distributed within the silicate minerals olivine and pyroxene grains and within the rims of the oxide mineral ilmenite, likely resulting from the thermal decomposition of olivine, pyroxene, and ilmenite. The presence of elemental iron has a great influence on the electromagnetic sorting, thermal infrared absorption, and catalytic reaction processes of lunar soil samples. The development of simulated lunar soil should fully consider the characteristics of the symbiotic combination of elemental iron and ilmenite, olivine, and pyroxene.

[0004] Therefore, in order to carry out extensive research on in-situ lunar soil resource utilization technology, it is necessary to develop simulated lunar soil suitable for mineral sorting and metal oxide smelting, so that its mineral composition and electromagnetic properties can be as close as possible to real lunar soil samples.

[0005] Patent number CN201811416830.7 discloses a method for preparing magnetically sensitive simulated lunar soil. This method involves mixing volcanic ash powder close to the actual lunar soil with magnetite, adding a pore-forming agent, and pre-pressing the mixture into a compact, high-temperature sintered form. Mechanical crushing, screening, and drying are then performed to obtain the magnetically sensitive simulated lunar soil. This technology has two major drawbacks, preventing it from being used for magnetic separation and smelting of minerals: 1) Volcanic ash inevitably contains a certain amount of iron oxide, which has a decisive influence on the magnetic properties of the sample; 2) The addition of a fixed ratio of magnetite to the sample does not conform to the mineral composition characteristics of lunar soil, interfering with the magnetic separation process and the smelting research of metal oxides.

[0006] The paper "Progress in Research on Simulated Lunar Regolith and CUG-1A Simulated Lunar Regolith" describes the sample source and development process for a simulated lunar regolith. This involves collecting basaltic volcanic rock samples from the Earth's surface, drying them at 200°C, and then crushing them. The samples are then screened using a multi-stage screening tool and remixed according to the vacuum-cleaned lunar regolith particle ratio to obtain the final product. This product has two technical requirements that make it unsuitable for sorting and alchemical purposes: 1) the combined water and hydroxyl groups in hydrous minerals such as zeolite and mica cannot be removed at 200°C; and 2) the sample contains a small amount of primary magnetite, which would adversely affect magnetic separation studies of the lunar regolith. Summary of the Invention

[0007] In order to solve one or more technical problems existing in the prior art, the present invention provides a method for preparing simulated lunar soil suitable for resource utilization.

[0008] The present invention solves the above-mentioned technical problem with the following technical solution: A method for preparing simulated lunar soil suitable for resource utilization comprises the following steps:

[0009] S1, crushing the basalt sample and performing a primary magnetic separation to obtain a primary magnetic separation sample, wherein the magnetite content in the primary magnetic separation sample is lower than the magnetite content in the basalt sample;

[0010] S2, grinding the primary magnetic separation sample, and heating the ground primary magnetic separation sample to undergo a hydrogen reduction reaction, thereby removing hydrous minerals in the primary magnetic separation sample and reducing the remaining iron oxides in the primary magnetic separation sample into elemental iron, thereby obtaining a hydrogen reduction product;

[0011] S3, performing secondary magnetic separation on the hydrogen reduction product to remove elemental iron in S2, and drying the iron-removed sample to obtain a secondary magnetic separation sample for later use;

[0012] S4, mixing the ilmenite powder with a reducing gas to react to obtain an ilmenite mixture containing elemental iron, and then sintering and crushing to obtain ilmenite particles;

[0013] S5, mixing the secondary magnetic separation sample obtained in S4 and the ilmenite particles obtained in S5 according to a preset mass ratio, pressing the mixture into tablets, and then sintering the mixture in an inert atmosphere to obtain a mixed sintered sample;

[0014] S6. Crushing the mixed sintered sample to obtain simulated lunar soil particles.

[0015] The beneficial effects of the present invention are: the preparation method of simulated lunar soil suitable for resource utilization of the present invention first crushes the basalt sample and performs initial magnetic separation, which can remove most of the strongly magnetic minerals, and destroys the water-containing mineral structure in the sample through heating and hydrogen reduction reaction, removes the adsorbed water, interlayer water and structural water therein, and at the same time reduces the remaining iron metal oxides such as magnetite and hematite into elemental iron. In addition, the silicate minerals olivine and pyroxene are reduced to elemental iron to a low degree, which is in line with the actual symbiotic combination law of lunar soil minerals.

[0016] The present invention prepares ilmenite particles separately, that is, partially reduces the ilmenite powder so that the sample contains nano-iron (i.e., elemental iron), which conforms to the characteristics of typical lunar soil samples and is conducive to theoretical research on magnetic separation.

[0017] The simulated lunar soil particles of the present invention do not contain ferromagnetic minerals and their oxides, and will not interfere with the magnetic separation, metallurgical theory research and resource utilization evaluation of lunar soil particles.

[0018] The present invention first removes most of the strong magnetic minerals such as magnetite, and then removes the elemental iron reduced from the iron oxide mineral, ensuring that the nano-iron in the sample only coexists with silicate minerals and ilmenite particles.

[0019] On the basis of the above technical solution, the present invention can also be improved as follows.

[0020] Furthermore, in S1, the basalt sample is crushed into sample particles no larger than 1 mm, and the sample particles are subjected to primary magnetic separation.

[0021] Furthermore, in S2, the primary magnetic separation sample is ground to less than 50 μm, and hydrogen is introduced into a tubular furnace to perform a heating hydrogen reduction reaction on the ground primary magnetic separation sample. The reaction temperature is 1000°C to 1100°C, the reaction time is 1.5h to 3h, and the reaction gas flow rate is 500ml / min to 700ml / min.

[0022] The beneficial effect of adopting the above further solution is that by limiting the conditions of the heating hydrogen reduction reaction, the reaction efficiency is higher and the reaction effect is better.

[0023] Furthermore, in S4, the reducing gas is an inert gas containing 2.5% to 3.5% by volume of hydrogen.

[0024] Further, in S4, the ilmenite powder is mixed with the reducing gas for reaction, including: heating the ilmenite powder and the reducing gas for reduction reaction at 750°C to 850°C, the reaction time is 13min to 16min, and the flow rate of the reducing gas is 250ml / min to 350ml / min.

[0025] The beneficial effect of adopting the above further solution is that, by limiting the reduction reaction conditions of the ilmenite powder, the mass percentage of elemental iron in the ilmenite mixture is ensured to meet actual needs.

[0026] Furthermore, in S4, the mass percentage of elemental iron in the ilmenite mixture is 5.5% to 6.5%.

[0027] Further, in S4, ilmenite particles are obtained by sintering and crushing, including: sintering the ilmenite mixture in a nitrogen atmosphere at 900° C. to 1100° C. for 0.8 h to 1.2 h, taking out and crushing to obtain ilmenite particles with a particle size of 45 μm to 60 μm.

[0028] Furthermore, in S5, the preset mass ratio is 10:1; the mixture of the secondary magnetic separation sample and the ilmenite particles is wet-mixed with anhydrous ethanol using a ball mill, naturally dried, mixed again, and then tabletted.

[0029] Furthermore, in S5, the volume ratio of anhydrous ethanol to the mixture is 3:1, the ball mill speed is 750 rpm to 850 rpm, and the wet mixing time is 1.5 h to 2.5 h;

[0030] The pressed samples were placed in a vacuum sintering furnace and sintered in an inert atmosphere, and then cooled in an inert atmosphere to obtain mixed sintered samples.

[0031] Furthermore, in S6, the crushed particle size of the mixed sintered sample is no more than 1 mm. After crushing, the crushed sample is sieved using a multi-stage sieve, and simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain simulated lunar soil.

[0032] The simulated lunar soil prepared by the preparation method of the simulated lunar soil suitable for resource utilization of the present invention can meet the following typical lunar soil mineral composition and magnetic characteristics: the sample does not contain water-containing minerals such as mica, chlorite, montmorillonite, amphibole, zeolite, etc.; the sample does not contain iron-containing oxides such as hematite, magnetite, etc.; the magnetic oxide in the sample is ilmenite, and the nano-iron element is associated with trace phases in the silicate mineral olivine, pyroxene and the oxide mineral ilmenite. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the phase composition diagram of the original basalt sample in Example 2;

[0034] Figure 2 This is the phase composition diagram of the primary magnetic separation sample in Example 2;

[0035] Figure 3 is the phase composition diagram of the hydrogen reduction product in Example 2;

[0036] Figure 4 This is the phase composition diagram of the secondary magnetic separation sample in Example 2;

[0037] Figure 5 is the phase composition diagram of ilmenite particles in Example 2;

[0038] Figure 6 This is the phase composition diagram of the mixed sintered sample in Example 2;

[0039] Figure 7a This is the energy spectrum test point map of ilmenite particles in the mixed sintered sample in Example 2;

[0040] Figure 7b This is the result of energy spectrum analysis of ilmenite particles in the mixed sintered sample in Example 2;

[0041] Figure 7c This is the energy spectrum test point map of the iron element coexisting with the ilmenite particles in the mixed sintered sample in Example 2;

[0042] Figure 7d This is a diagram showing the energy spectrum analysis results of the iron element coexisting with the ilmenite particles in the mixed sintered sample in Example 2;

[0043] Figure 8a This is the energy spectrum test point map of silicate mineral particles in the mixed sintered sample in Example 2;

[0044] Figure 8b This is the result of energy spectrum analysis of silicate mineral particles in the mixed sintered sample in Example 2;

[0045] Figure 8c This is the energy spectrum test point map of the iron element coexisting with silicate mineral particles in the mixed sintered sample in Example 2;

[0046] Figure 8d This is a diagram showing the energy spectrum analysis results of the iron element coexisting with the silicate mineral particles in the mixed sintered sample in Example 2;

[0047] Figure 9 This is the microscopic morphology of the sample after crushing the mixed sintered sample in Example 2;

[0048] Figure 10 The particle size distribution diagram of the simulated lunar soil obtained in S6 in Example 2;

[0049] Figure 11This is the mass ratio magnetic susceptibility diagram of the simulated lunar soil obtained by S6 in Example 2. DETAILED DESCRIPTION

[0050] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0051] Example 1

[0052] A method for preparing simulated lunar soil suitable for resource utilization in this embodiment includes the following steps:

[0053] S1, crushing the basalt sample and performing a primary magnetic separation to obtain a primary magnetic separation sample, wherein the magnetite content in the primary magnetic separation sample is lower than the magnetite content in the basalt sample;

[0054] Specifically, the basalt sample is crushed into sample particles no larger than 1mm, and the sample particles are subjected to primary magnetic separation. The basalt sample can be crushed into fragments using a jaw crusher, and then the fragments are processed into sample particles of 1mm in size using a disc crusher. The sample particles are subjected to X-ray diffraction phase analysis (experimental conditions: voltage 40kV, current 150mA, scanning rate 2° / min, and subsequent samples are tested under this condition). Figure 1 As shown in the figure, the basalt samples obviously contain hydrous minerals (analcite), strong magnetic minerals (magnetite), and iron oxide (hematite). In order to reduce the workload of subsequent sample processing, a permanent magnetic dry magnetic separator (equipment model CTX1030, cylinder speed 80r / min, cylinder surface field strength 300mT) is first used to perform primary magnetic separation on the original sample to remove most of the strong magnetic mineral magnetite. The magnetite content in the sample after magnetic separation is significantly reduced, as shown in the figure. Figure 2 As shown, compared Figure 1 and Figure 2 It can be found that Figure 2 The magnetite in the ore is removed by magnetic separation, but it contains hematite and the hydrous mineral analcime.

[0055] S2, grinding the primary magnetic separation sample, and heating the ground primary magnetic separation sample to undergo a hydrogen reduction reaction, thereby removing the hydrous minerals in the primary magnetic separation sample, and reducing the remaining iron-containing oxides in the primary magnetic separation sample to elemental iron, and reducing the silicate minerals olivine and pyroxene to a low degree, thereby obtaining a hydrogen reduction product;

[0056] In S2, the primary magnetic separation sample is ground to less than 50μm, and a tube furnace (equipment model GSL-1750X-K) is used to introduce 99.999% pure hydrogen to perform a heating hydrogen reduction reaction on the ground primary magnetic separation sample. The reaction temperature is 1000℃, the reaction time is 3h, and the reaction gas (hydrogen) flow rate is 500ml / min. By limiting the conditions of the heating hydrogen reduction reaction, the reaction efficiency is higher and the reaction effect is better. High temperature will effectively destroy the hydrous mineral structure in the sample, remove the adsorbed water, interlayer water and structural water therein, and at the same time reduce the remaining iron metal oxides such as magnetite and hematite into elemental iron. In addition, the iron-containing minerals olivine (forsterite) and pyroxene (augite) are reduced to elemental iron to a low degree, which is consistent with the actual symbiotic combination law of lunar soil minerals.

[0057] S3, the hydrogen reduction product is subjected to secondary magnetic separation to remove the elemental iron particles in S2, and the sample after iron removal is dried to obtain a secondary magnetic separation sample for use; specifically, a wet permanent magnetic separator (equipment model CTN1030) is used, with a cylinder surface field strength of 400mT, a cylinder speed of 26r / min, and an induction roller unloading. The fine-grained sample is subjected to weak magnetic separation to remove the strongly magnetic mineral elemental iron therein, and the sample after iron removal is dried at 105°C for use.

[0058] S4, mixing ilmenite powder (commercially available conventional ilmenite powder may be used) with a reducing gas to react to obtain an ilmenite mixture containing elemental iron, and then sintering and pulverizing to obtain ilmenite particles;

[0059] In S4, the reaction conditions for obtaining ilmenite particles are as follows: ilmenite powder is subjected to a heating reduction reaction with a reducing gas at 750°C for 16 minutes at a flow rate of 250 ml / min. The reducing gas is an inert gas (e.g., nitrogen) containing 2.5% by volume of hydrogen. Ultimately, the mass percentage of elemental iron in the ilmenite mixture is 5.5%. The ilmenite mixture is then sintered in a nitrogen atmosphere at 900°C for 1.2 hours, removed, and crushed to obtain ilmenite particles with a particle size of 45 μm.

[0060] This plan prepares ilmenite particles separately, mainly because ilmenite particles are distributed in granular and lamellar forms in lunar soil particles, and nano-iron is mainly attached to the surface of ilmenite particles and is in mosaic contact with other components. If ilmenite, nano-elemental iron powder and secondary magnetic separation samples are directly mixed, on the one hand, the ilmenite will be widely impregnated and attached to the surface of other components, and cannot form particles alone, which is not conducive to the subsequent characterization test of ilmenite particles. On the other hand, it may cause nano-iron particles to separate from the ilmenite and adhere to the surface of other components, changing the electromagnetic characteristics of other components, which is not conducive to the research and testing of electromagnetic separation.

[0061] S5, mixing the secondary magnetic separation sample obtained in S4 and the ilmenite particles obtained in S5 according to a preset mass ratio, pressing the mixture into tablets, and then sintering the mixture in an inert atmosphere to obtain a mixed sintered sample;

[0062] In S5, the preset mass ratio is 10:1. The mixture of the secondary magnetic separation sample and the ilmenite particles is wet-mixed with anhydrous ethanol using a ball mill, air-dried, mixed again, and then pressed into tablets. In S5, the volume ratio of anhydrous ethanol to the mixture is 3:1, the ball mill speed is 750 r / min, and the wet-mixing time is 2.5 hours. The pressed sample is placed in a vacuum sintering furnace at 1000°C in an inert atmosphere (nitrogen) for 2 hours, and cooled in an inert atmosphere to obtain a mixed sintered sample.

[0063] S6. Crushing the mixed sintered sample to obtain simulated lunar soil particles.

[0064] In S6, the crushed particle size of the mixed sintered sample is no more than 1 mm. After crushing, the crushed sample is screened using a multi-stage sieve, and simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain simulated lunar soil.

[0065] Specifically, the mixed sintered samples were crushed using a blade-type rotary crusher (FB-500) at a speed of 10,000 r / min, achieving a crushing fineness of less than 1 mm. The crushing process randomly shattered the samples into amorphous, angular particles. The samples were then screened using a multi-stage sieve and mixed according to the particle size composition of lunar regolith, yielding lunar regolith particles with similar mineralogy and particle size composition. Furthermore, magnetic balance measurements of the samples revealed a mass-to-magnetic susceptibility similar to that of the Apollo lunar regolith samples.

[0066] Example 2

[0067] A method for preparing simulated lunar soil suitable for resource utilization in this embodiment includes the following steps:

[0068] S1, crushing the basalt sample and performing primary magnetic separation to obtain a primary magnetic separation sample, wherein the iron ore content in the primary magnetic separation sample is lower than the iron ore content in the basalt sample;

[0069] Specifically, the basalt sample is crushed into sample particles no larger than 1mm, and the sample particles are subjected to primary magnetic separation. The basalt sample can be crushed into fragments using a jaw crusher, and then the fragments are processed into sample particles of 1mm in size using a disc crusher. The sample particles are subjected to X-ray diffraction phase analysis (experimental conditions: voltage 40kV, current 150mA, scanning rate 2° / min, and subsequent samples are tested under this condition). Figure 1As shown in the figure, the basalt samples obviously contain hydrous minerals (analcite), strong magnetic minerals (magnetite), and iron oxide (hematite). In order to reduce the workload of subsequent sample processing, a permanent magnetic dry magnetic separator (equipment model CTX1030, cylinder speed 80r / min, cylinder surface field strength 300mT) is first used to perform primary magnetic separation on the original sample to remove most of the strong magnetic mineral magnetite. The magnetite content in the sample after magnetic separation is significantly reduced, as shown in the figure. Figure 2 As shown, compared Figure 1 and Figure 2 It can be found that Figure 2 The magnetite in the ore is removed by magnetic separation, but it contains hematite and the hydrous mineral analcime.

[0070] S2, grinding the primary magnetic separation sample, and heating the ground primary magnetic separation sample to undergo a hydrogen reduction reaction, thereby removing hydrous minerals in the primary magnetic separation sample and reducing the remaining iron-containing oxides in the primary magnetic separation sample to elemental iron, and reducing the silicate minerals olivine and pyroxene to a low degree to obtain a hydrogen reduction product;

[0071] In S2, the primary magnetic separation sample is ground to less than 50 μm, and a tubular furnace (equipment model GSL-1750X-K) is used to introduce 99.999% pure hydrogen to perform a heated hydrogen reduction reaction on the ground primary magnetic separation sample. The reaction temperature is 1050°C, the reaction time is 2 hours, and the reaction gas (hydrogen) flow rate is 600 ml / min. By limiting the conditions of the heated hydrogen reduction reaction, the reaction efficiency is higher and the reaction effect is better. High temperature will effectively destroy the water-containing mineral structure in the sample, remove the adsorbed water, interlayer water and structural water therein, and at the same time reduce the remaining iron metal oxides such as magnetite and hematite to elemental iron (Iron). In addition, the iron-containing minerals olivine (Forsterite) and pyroxene (Augite) are reduced to elemental iron to a low degree, which is in line with the actual symbiotic combination law of lunar soil minerals. The X-ray diffraction phase analysis diagram of the primary magnetic separation sample after the heated hydrogen reduction reaction is shown in the figure below. Figure 3 As shown. Figure 2 and Figure 3 It was found that after the initial magnetic separation sample was heated and hydrogen reduced, it contained elemental iron, but no longer contained iron oxides (hematite and magnetite, etc.) and hydrated minerals.

[0072] S3, the hydrogen reduction product is subjected to secondary magnetic separation to remove the elemental iron in S2, and the sample after iron removal is dried to obtain the secondary magnetic separation sample for use; specifically, a wet permanent magnetic separator (equipment model CTN1030) is used, with a cylinder surface field strength of 400mT, a cylinder speed of 26r / min, and an induction roller unloading. The fine-grained sample is subjected to weak magnetic separation to remove the strongly magnetic mineral elemental iron particles therein. The sample after iron removal is dried at 105°C for use. The X-ray diffraction phase analysis diagram of the secondary magnetic separation sample is shown in the figure below: Figure 4 shown.

[0073] S4, mixing ilmenite powder (commercially available conventional ilmenite powder may be used) with a reducing gas to react to obtain an ilmenite mixture containing elemental iron, and then sintering and crushing to obtain ilmenite particles;

[0074] In S4, the reaction conditions for obtaining ilmenite particles are as follows: heating the ilmenite powder with a reducing gas at 800°C for a reduction reaction, the reaction time is 15 minutes, the flow rate of the reducing gas is 300 ml / min, and the reducing gas is an inert gas (such as nitrogen) containing 3% hydrogen by volume; finally, the mass percentage of elemental iron in the ilmenite mixture is 6%. The ilmenite mixture is then sintered in a nitrogen atmosphere at 1000°C for 1 hour, taken out and crushed to obtain ilmenite particles with a particle size of 50 μm. The X-ray diffraction phase analysis diagram of the ilmenite particles is shown below. Figure 5 As shown, ilmenite and elemental iron coexist.

[0075] This plan prepares ilmenite particles separately, mainly because ilmenite particles are distributed in granular and lamellar forms in lunar soil particles, and nano-iron is mainly attached to the surface of ilmenite particles and is in mosaic contact with other components. If ilmenite, nano-elemental iron powder and secondary magnetic separation samples are directly mixed, on the one hand, the ilmenite will be widely impregnated and attached to the surface of other components, and cannot form particles alone, which is not conducive to the subsequent characterization test of ilmenite particles. On the other hand, it may cause nano-iron particles to separate from the ilmenite and adhere to the surface of other components, changing the electromagnetic characteristics of other components, which is not conducive to the research and testing of electromagnetic separation.

[0076] S5, mixing the secondary magnetic separation sample obtained in S4 and the ilmenite particles obtained in S5 according to a preset mass ratio, pressing the mixture into tablets, and then sintering the mixture in an inert atmosphere to obtain a mixed sintered sample;

[0077] In S5, the preset mass ratio is 10:1; a ball mill is used to wet-mix the mixture of the secondary magnetic separation sample and the ilmenite particles with anhydrous ethanol, and the mixture is naturally dried and mixed again before tableting. In S5, the volume ratio of anhydrous ethanol to the mixture is 3:1, the ball mill speed is 800r / min, and the wet mixing time is 2h; the tableted sample is placed in a vacuum sintering furnace and sintered at 1000℃ in an inert atmosphere (nitrogen) for 2h, and a mixed sintered sample is obtained after cooling in an inert atmosphere. X-ray diffraction phase analysis of the mixed sintered sample shows that, Figure 6 As shown, it contains iron and ilmenite; the mixed sintered sample was subjected to energy spectrum scanning (equipment model: scanning electron microscope SU5000, acceleration voltage 10kV, working distance ~10mm), as shown Figure 7a 、 Figure 7b 、 Figure 7c and Figure 7d It can be seen that the mixed sintered samples contain ilmenite and iron, such as Figure 8a 、 Figure 8b 、 Figure 8c and Figure 8d The mixed sintered samples contain silicate minerals and elemental iron. Therefore, the coexistence of elemental iron with ilmenite and elemental iron with silicate minerals is consistent with the typical characteristics of lunar soil.

[0078] S6. Crushing the mixed sintered sample to obtain simulated lunar soil particles.

[0079] In S6, the crushed particle size of the mixed sintered sample is no more than 1 mm. After crushing, the crushed sample is screened using a multi-stage sieve, and simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain simulated lunar soil.

[0080] Specifically, a blade-type rotary crusher (FB-500) was used to crush the mixed sintered samples at a rotation speed of 10,000 r / min and a crushing fineness of less than 1 mm. During the crushing process, the samples were randomly broken into amorphous, angular particles. The samples were sieved using a multi-stage sieve and mixed according to the particle size composition of the lunar soil to obtain lunar soil particles with similar mineral composition and particle size composition. After the samples were measured by a magnetic balance, their mass specific magnetic susceptibility was similar to that of the Apollo lunar soil samples. The sample micromorphology of the crushed mixed sintered sample (equipment model: digital microscope Smartzoom 5) is shown below. Figure 9 As shown; the particle size distribution diagram of the mixed sintered sample after crushing (equipment model: laser particle size analyzer JL-1155, standard test sieve 0.010mm~4.75mm) is as follows Figure 10 As shown, Figure 10 In the example, Lunar soil 14163 is the Apollo 14 lunar soil, FJS-1 is the simulated lunar soil produced by Shimizu Corporation of Japan, JSC-1 is the simulated lunar soil produced by NASA of the United States, and CSU-1A is the simulated lunar soil developed in Example 2; Figure 10 It can be seen that the particle size of the simulated lunar soil prepared in this example is closest to the Apollo 14 lunar soil.

[0081] The mass specific magnetic susceptibility of the simulated lunar soil particles obtained in this example (equipment model: Goue magnetic balance CTP-Ⅱ) is as follows Figure 11 As shown, Figure 11 Among them, Apollo 11 to 17 are the lunar soils of Apollo 11, 12, 14, 15, 16 and 17 respectively, and CSU-1A is the simulated lunar soil developed this time. Figure 11 It can be seen that the mass specific magnetic susceptibility of the simulated lunar soil prepared in this embodiment falls within the mass specific magnetic susceptibility range of the Apollo lunar soil samples.

[0082] Example 3

[0083] A method for preparing simulated lunar soil suitable for resource utilization in this embodiment includes the following steps:

[0084] S1, crushing the basalt sample and performing a primary magnetic separation to obtain a primary magnetic separation sample, wherein the magnetite content in the primary magnetic separation sample is lower than the magnetite content in the basalt sample;

[0085] Specifically, the basalt sample is crushed into sample particles no larger than 1mm, and the sample particles are subjected to primary magnetic separation. The basalt sample can be crushed into fragments using a jaw crusher, and then the fragments are processed into sample particles of 1mm in size using a disc crusher. The sample particles are subjected to X-ray diffraction phase analysis (experimental conditions: voltage 40kV, current 150mA, scanning rate 2° / min, and subsequent samples are tested under this condition). Figure 1 As shown in the figure, the basalt samples obviously contain hydrous minerals (analcite), strong magnetic minerals (magnetite), and iron oxide (hematite). In order to reduce the workload of subsequent sample processing, a permanent magnetic dry magnetic separator (equipment model CTX1030, cylinder speed 80r / min, cylinder surface field strength 300mT) is first used to perform primary magnetic separation on the original sample to remove most of the strong magnetic mineral magnetite. The magnetite content in the sample after magnetic separation is significantly reduced, as shown in the figure. Figure 2 As shown, compared Figure 1 and Figure 2 It can be found that Figure 2 The magnetite in the ore is removed by magnetic separation, but it contains hematite and the hydrous mineral analcime.

[0086] S2, grinding the primary magnetic separation sample, and heating the ground primary magnetic separation sample to undergo a hydrogen reduction reaction, thereby removing hydrous minerals in the primary magnetic separation sample and reducing the remaining iron oxides in the primary magnetic separation sample into elemental iron, thereby obtaining a hydrogen reduction product;

[0087] In S2, the primary magnetic separation sample is ground to less than 50μm, and a tube furnace (equipment model GSL-1750X-K) is used to introduce 99.999% pure hydrogen to perform a heating hydrogen reduction reaction on the ground primary magnetic separation sample. The reaction temperature is 1100°C, the reaction time is 1.5 hours, and the reaction gas (hydrogen) flow rate is 700ml / min. By limiting the conditions of the heating hydrogen reduction reaction, the reaction efficiency is higher and the reaction effect is better. High temperature will effectively destroy the hydrous mineral structure in the sample, remove the adsorbed water, interlayer water and structural water therein, and at the same time reduce the remaining iron metal oxides such as magnetite and hematite into elemental iron. In addition, the iron-containing minerals olivine (forsterite) and pyroxene (augite) are reduced to elemental iron to a low degree, which is consistent with the actual symbiotic combination law of lunar soil minerals.

[0088] S3, the hydrogen reduction product is subjected to secondary magnetic separation to remove the elemental iron in S2, and the sample after iron removal is dried to obtain a secondary magnetic separation sample for use; specifically, a wet permanent magnetic separator (equipment model CTN1030) is used, with a cylinder surface field strength of 400mT, a cylinder speed of 26r / min, and an induction roller unloading. The fine-grained sample is subjected to weak magnetic separation to remove the strongly magnetic mineral elemental iron therein, and the sample after iron removal is dried at 105°C for use.

[0089] S4, mixing ilmenite powder (commercially available conventional ilmenite powder may be used) with a reducing gas to react to obtain an ilmenite mixture containing elemental iron, and then sintering and crushing to obtain ilmenite particles;

[0090] In S4, the reaction conditions for obtaining ilmenite particles are as follows: ilmenite powder is subjected to a heating reduction reaction with a reducing gas at 850°C for 13 minutes, with a flow rate of 350 ml / min. The reducing gas is an inert gas (e.g., nitrogen) containing 3.5% by volume of hydrogen. Ultimately, the mass percentage of elemental iron in the ilmenite mixture is reduced to 6.5%. The ilmenite mixture is then sintered in a nitrogen atmosphere at 1100°C for 0.8 hours, removed, and crushed to obtain ilmenite particles with a particle size of 60 μm.

[0091] This plan prepares ilmenite particles separately, mainly because ilmenite particles are distributed in granular and lamellar forms in lunar soil particles, and nano-iron is mainly attached to the surface of ilmenite particles and is in mosaic contact with other components. If ilmenite, nano-elemental iron powder and secondary magnetic separation samples are directly mixed, on the one hand, the ilmenite will be widely impregnated and attached to the surface of other components, and cannot form particles alone, which is not conducive to the subsequent characterization test of ilmenite particles. On the other hand, it may cause nano-iron particles to separate from the ilmenite and adhere to the surface of other components, changing the electromagnetic characteristics of other components, which is not conducive to the research and testing of electromagnetic separation.

[0092] S5, mixing the secondary magnetic separation sample obtained in S4 and the ilmenite particles obtained in S5 according to a preset mass ratio, pressing the mixture into tablets, and then sintering the mixture in an inert atmosphere to obtain a mixed sintered sample;

[0093] In S5, the preset mass ratio is 10:1. The mixture of the secondary magnetic separation sample and the ilmenite particles is wet-mixed with anhydrous ethanol using a ball mill, air-dried, mixed again, and then pressed into tablets. In S5, the volume ratio of anhydrous ethanol to the mixture is 3:1, the ball mill speed is 850 r / min, and the wet-mixing time is 1.5 hours. The pressed sample is placed in a vacuum sintering furnace at 1000°C in an inert atmosphere (nitrogen) for 2 hours, and cooled in an inert atmosphere to obtain a mixed sintered sample.

[0094] S6. Crushing the mixed sintered sample to obtain simulated lunar soil particles.

[0095] In S6, the crushed particle size of the mixed sintered sample is no more than 1 mm. After crushing, the crushed sample is screened using a multi-stage sieve, and simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain simulated lunar soil.

[0096] Specifically, the mixed sintered samples were crushed using a blade-type rotary crusher (FB-500) at a speed of 10,000 r / min, achieving a crushing fineness of less than 1 mm. The crushing process randomly shattered the samples into amorphous, angular particles. The samples were then screened using a multi-stage sieve and mixed according to the particle size composition of lunar regolith, yielding lunar regolith particles with similar mineralogy and particle size composition. Furthermore, magnetic balance measurements of the samples revealed a mass-to-magnetic susceptibility similar to that of the Apollo lunar regolith samples.

[0097] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0098] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for preparing simulated lunar soil suitable for resource utilization, characterized in that: The following steps are involved: S1, crushing the basalt sample and performing a primary magnetic separation to obtain a primary magnetic separation sample, wherein the magnetite content in the primary magnetic separation sample is lower than the magnetite content in the basalt sample; S2, grinding the primary magnetic separation sample, and heating the ground primary magnetic separation sample to undergo a hydrogen reduction reaction, thereby removing the hydrous minerals in the primary magnetic separation sample and reducing the remaining iron-containing oxides in the primary magnetic separation sample to elemental iron, and reducing the silicate minerals olivine and pyroxene to a low degree to obtain a hydrogen reduction product; S3, performing secondary magnetic separation on the hydrogen reduction product to remove elemental iron in S2, and drying the iron-removed sample to obtain a secondary magnetic separation sample for later use; S4, mixing the ilmenite powder with a reducing gas to react to obtain an ilmenite mixture containing elemental iron, and then sintering and crushing to obtain ilmenite particles; S5, mixing the secondary magnetic separation sample obtained in S3 and the ilmenite particles obtained in S4 according to a preset mass ratio, pressing the mixture into tablets, and then sintering the mixture in an inert atmosphere to obtain a mixed sintered sample; S6. Crushing the mixed sintered sample to obtain simulated lunar soil particles.

2. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S1, the basalt sample is crushed into sample particles no larger than 1 mm, and the sample particles are subjected to primary magnetic separation.

3. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S2, the primary magnetic separation sample is ground to less than 50 μm, and hydrogen is introduced into a tubular furnace to perform a heating hydrogen reduction reaction on the ground primary magnetic separation sample. The reaction temperature is 1000°C to 1100°C, the reaction time is 1.5h to 3h, and the reaction gas flow rate is 500ml / min to 700ml / min.

4. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S4, the reducing gas is an inert gas containing 2.5% to 3.5% by volume of hydrogen.

5. The method for preparing simulated lunar soil suitable for resource utilization according to claim 4, characterized in that: In S4, the ilmenite powder is mixed with the reducing gas for reaction, including: heating the ilmenite powder and the reducing gas at 750° C. to 850° C. for reduction reaction, the reaction time is 13 min to 16 min, and the flow rate of the reducing gas is 250 ml / min to 350 ml / min.

6. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S4, the mass percentage of elemental iron in the ilmenite mixture is 5.5% to 6.5%.

7. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S4, ilmenite particles are obtained by sintering and crushing, including: sintering the ilmenite mixture in a nitrogen atmosphere at 900° C. to 1100° C. for 0.8 h to 1.2 h, taking out and crushing to obtain ilmenite particles with a particle size of 45 μm to 60 μm.

8. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S5, the preset mass ratio is 10:1; the mixture of the secondary magnetic separation sample and the ilmenite particles is wet-mixed with anhydrous ethanol using a ball mill, naturally dried, mixed again, and then tabletted.

9. The method for preparing simulated lunar soil suitable for resource utilization according to claim 8, characterized in that: In S5, the volume ratio of anhydrous ethanol to the mixture is 3:1, the ball mill speed is 750 rpm to 850 rpm, and the wet mixing time is 1.5 h to 2.5 h; The pressed samples were placed in a vacuum sintering furnace and sintered in an inert atmosphere, and then cooled in an inert atmosphere to obtain mixed sintered samples.

10. The method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S6, the crushed particle size of the mixed sintered sample is no more than 1 mm. After crushing, the crushed sample is screened using a multi-stage sieve, and simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain simulated lunar soil.

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