Preparation method of simulated lunar soil suitable for resource utilization

Abstract

The invention relates to a preparation method of simulated lunar soil suitable for resource utilization, which comprises the following steps: S1, crushing a basalt sample and carrying out primary magnetic separation to obtain a primary magnetic separation sample; s2, the primary magnetic separation sample is ground, the ground primary magnetic separation sample is subjected to a heating hydrogen reduction reaction, and a hydrogen reduction product is obtained; s3, carrying out secondary magnetic separation on the hydrogen reduction product, and drying the iron-removed sample to obtain a secondary magnetic separation sample for later use; s4, the ilmenite powder and reducing gas are mixed to react, an ilmenite mixture containing elemental iron is obtained, and then the ilmenite mixture is sintered and smashed to obtain ilmenite particles; s5, mixing the secondary magnetic separation sample obtained in the step S4 and the ilmenite particles obtained in the step S5 according to a preset mass ratio, performing tabletting treatment, and sintering in an inert atmosphere to obtain a mixed sintering sample; and S6, crushing the mixed sintering sample to obtain the simulated lunar soil particles. The simulated lunar soil conforms to the actual symbiotic combination rule of lunar soil minerals.

Description

Technical Field

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

[0002] The existing simulated lunar soil is mainly used for engineering application research, mainly including rock and soil mechanics, electrostatic migration, 3D construction, etc., and simulated lunar soil samples for mineral resource selection and smelting have not yet been developed. The resource utilization of lunar soil minerals focuses on ilmenite. The research on ilmenite mineral sorting, titanium and iron smelting, and hydrogen reduction water production faces a series of key technical problems, requiring a large number of simulated lunar soil samples for in-depth theoretical research and destructive testing. Such samples should have typical lunar soil physical and chemical characteristics, and there should be no interfering components for mineral sorting and smelting.

[0003] The existing simulated lunar soil is mostly made of 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 suffer 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. The lunar soil contains extremely low levels of magnetite, about a few thousandths of an order of magnitude, which has limited effect on the magnetic characteristics of the lunar soil. However, the small amount of magnetite in the existing simulated lunar soil has a decisive influence on the magnetic susceptibility of the simulated lunar soil, which will affect the simulation test results of ground electromagnetic mineral separation. At the same time, the hydrous altered minerals (mica, amphibole, montmorillonite, zeolite, etc.) widely present in ground basalt will also affect the kinetic evaluation of the metallurgical reduction process of metal oxides (ilmenite). The water produced by them and the water released by hydrous minerals during high temperature will directly interfere with the determination of the water content of the reaction products, which is not conducive to the study and evaluation of the chemical reaction kinetic process. The interfering minerals hematite and magnetite will also participate in the reduction, affecting the measurement of the reduction degree of iron. In addition, studies have shown that the lunar soil also contains a small amount of elemental iron, which is formed by space weathering and is widely distributed in the silicate mineral olivine and pyroxene particles and the edges of the oxide mineral ilmenite. It may be formed by 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, and make it as close as possible to the real lunar soil samples in terms of mineral composition and electromagnetic properties.

[0005] The invention patent with the patent number CN201811416830.7 discloses a method for preparing magnetically sensitive simulated lunar soil. The preparation method uses a mixture of volcanic ash powder and magnetite close to the real lunar soil, adds a pore-forming agent, pre-presses and sintered at high temperature, and obtains magnetically sensitive simulated lunar soil after mechanical crushing, screening, drying and other processes. This technology has two main shortcomings and cannot be used for mineral magnetic separation and smelting: ① Volcanic ash inevitably contains a certain amount of iron oxide, which has a decisive influence on the magnetic characteristics of the sample; ② A fixed ratio of magnetite is added to the sample, which does not conform to the mineral composition characteristics of the lunar soil, and interferes with the magnetic separation process and the smelting research of metal oxides.

[0006] The document "Research Progress of Simulated Lunar Soil and CUG-1A Simulated Lunar Soil" introduces the source and development process of a simulated lunar soil sample. First, basaltic volcanic rock samples are collected from the surface, dried at 200°C and crushed. After screening the samples with a multi-stage screening tool, they are remixed according to the vacuum lunar soil particle ratio to obtain the final product. There are two technical requirements for this product that are not suitable for sorting and alchemy needs: ① The combined water and hydroxyl groups in the zeolite, mica and other hydrous minerals in the sample cannot be removed at 200°C; ② The sample contains a small amount of primary magnetite, which has an adverse effect on the magnetic separation research of the lunar soil sample. Summary of the invention

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

[0008] The technical solution of the present invention to solve the above technical problems is as follows: A method for preparing simulated lunar soil suitable for resource utilization comprises the following steps:

[0009] S1, crushing the basalt sample and performing 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 the hydrous minerals in the primary magnetic separation sample and reducing the remaining iron-containing 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 sample after iron removal to obtain a secondary magnetic separation sample for standby use;

[0012] S4, mixing the ilmenite powder with a reducing gas to react, obtaining 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, and then tableting, and then sintering 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 as follows: the preparation method of simulated lunar soil suitable for resource utilization of the present invention first crushes the basalt sample and performs the initial magnetic separation, which can remove most of the strongly magnetic minerals, and destroys the water-containing mineral structure in the sample through heating hydrogen reduction reaction, removes the adsorbed water, interlayer water and structural water therein, and at the same time reduces the remaining magnetite, hematite and other iron metal oxides therein to elemental iron. In addition, the silicate minerals olivine and pyroxene are reduced to elemental iron to a low extent, 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 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, so as to ensure that the nano-iron in the sample only coexists with silicate minerals and ilmenite particles.

[0019] Based on 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] Further, in S2, the primary magnetic separation sample is ground to less than 50 μm, and hydrogen is introduced into a tubular furnace to heat the ground primary magnetic separation sample for hydrogen reduction reaction. 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 scheme 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, it is ensured that the mass percentage of elemental iron in the ilmenite mixture meets the 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; 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.

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

[0030] The pressed sample is placed in a vacuum sintering furnace for sintering in an inert atmosphere, and after cooling in an inert atmosphere, a mixed sintered sample is obtained.

[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 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 is the phase composition diagram of the original basalt sample in Example 2;

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

[0035] Figure 3 is a 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 a phase composition diagram of ilmenite particles in Example 2;

[0038] Figure 6 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 a diagram showing the results of energy spectrum analysis of ilmenite particles in the mixed sintered sample in Example 2;

[0041] Figure 7c This is a test point diagram of the energy spectrum of the single iron substance 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 result 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 a diagram showing the results of energy spectrum analysis of silicate mineral particles in the mixed sintered sample in Example 2;

[0045] Figure 8c This is a test point diagram of the energy spectrum of the single iron substance coexisting with the 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] Fig. 9 This is a microscopic morphology of the sample after the mixed sintered sample in Example 2 is crushed;

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

[0049] Fig.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 in conjunction with 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 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 1 mm, and the sample particles are subjected to primary magnetic separation. The basalt sample can be crushed into fragments by a jaw crusher, and then the fragments are processed into sample particles of 1 mm in size by 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 samples to remove most of the strongly magnetic mineral magnetite. The magnetite content in the samples 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 for hydrogen reduction reaction, 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 the silicate minerals olivine and pyroxene are reduced to a low degree, to obtain a hydrogen reduction product;

[0056] In S2, the primary magnetic separation sample is ground to less than 50μm, and a tubular furnace (equipment model GSL-1750X-K) is used to pass 99.999% pure hydrogen to heat the ground primary magnetic separation sample for hydrogen reduction reaction. 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 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 into 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.

[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 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, and 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, thereby obtaining an ilmenite mixture containing elemental iron, and then sintering and crushing the mixture to obtain ilmenite particles;

[0059] In S4, the reaction conditions for obtaining ilmenite particles are: heating the ilmenite powder and the reducing gas at 750°C for reduction reaction, the reaction time is 16 minutes, the flow rate of the reducing gas is 250 ml / min, and the reducing gas is an inert gas (such as nitrogen) containing 2.5% by volume of hydrogen; finally, the mass percentage of elemental iron in the ilmenite mixture is 5.5%. Then, the ilmenite mixture is sintered in a nitrogen atmosphere at 900°C for 1.2 hours, and the ilmenite particles with a particle size of 45 μm are obtained by taking out and crushing.

[0060] This scheme 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 surfaces of other components, and cannot form particles separately, 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 surfaces of other components, changing the electromagnetic characteristics of other components, which is not conducive to the research and experiment 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, and then tableting, and then sintering 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, and then 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 750r / min, and the wet mixing time is 2.5h; the tableted sample is placed in a vacuum sintering furnace at 1000℃ in an inert atmosphere (nitrogen) for 2h, and a mixed sintered sample is obtained after cooling in an inert atmosphere.

[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 sieved using a multi-stage sieve, and the simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain the simulated lunar soil.

[0065] Specifically, the mixed sintered samples were crushed by a blade-type rotary crusher (FB-500) at a speed of 10,000 r / min and a crushing fineness of less than 1 mm. During the crushing process, the samples were randomly crushed into amorphous and angular particles. The samples were sieved by 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.

[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 1 mm, and the sample particles are subjected to primary magnetic separation. The basalt sample can be crushed into fragments by a jaw crusher, and then the fragments are processed into sample particles of 1 mm in size by 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 samples to remove most of the strongly magnetic mineral magnetite. The magnetite content in the samples 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 for hydrogen reduction reaction, removing the hydrous minerals in the primary magnetic separation sample, and reducing the remaining iron-containing oxides in the primary magnetic separation sample into elemental iron, and the silicate minerals olivine and pyroxene are reduced to a low degree, to obtain hydrogen reduction products;

[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 carry out 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 following figure. 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 hydrous 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, and the fine-grained sample is subjected to weak magnetic separation to remove the strongly magnetic mineral elemental iron particles therein, and 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, thereby obtaining an ilmenite mixture containing elemental iron, and then sintering and crushing the mixture to obtain ilmenite particles;

[0074] In S4, the reaction conditions for obtaining ilmenite particles are: 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, and the ilmenite particles with a particle size of 50 μm are obtained by crushing. The X-ray diffraction phase analysis diagram of the ilmenite particles is shown in FIG. Figure 5 As shown, ilmenite and elemental iron coexist.

[0075] This scheme 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 surfaces of other components, and cannot form particles separately, 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 surfaces of other components, changing the electromagnetic characteristics of other components, which is not conducive to the research and experiment 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, and then tableting, and then sintering 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 is 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 It can be seen that the mixed sintered samples contain silicate minerals and iron. Therefore, the coexistence of iron and ilmenite, and iron and silicate minerals, conforms to 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 sieved using a multi-stage sieve, and the simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain the simulated lunar soil.

[0080] Specifically, a blade-type rotary crusher (FB-500) was used to crush the mixed sintered samples, with 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 microscopic morphology of the mixed sintered sample after crushing (equipment model: digital microscope Smartzoom 5) is shown below. Fig. 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 Fig.10 As shown, Fig.10 In the above, Lunar soil 14163 is the lunar soil of Apollo 14, FJS-1 is the simulated lunar soil of Shimizu Corporation of Japan, JSC-1 is the simulated lunar soil of NASA of the United States, and CSU-1A is the simulated lunar soil developed in Example 2; Fig.10 It can be seen that the particle size of the simulated lunar soil prepared in this embodiment 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: Fig.11 As shown, Fig.11 In the survey, Apollo 11~17 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. Fig.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 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 1 mm, and the sample particles are subjected to primary magnetic separation. The basalt sample can be crushed into fragments by a jaw crusher, and then the fragments are processed into sample particles of 1 mm in size by 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 samples to remove most of the strongly magnetic mineral magnetite. The magnetite content in the samples 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 the hydrous minerals in the primary magnetic separation sample and reducing the remaining iron-containing 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 50 μm, and a tubular furnace (equipment model GSL-1750X-K) is used to pass 99.999% pure hydrogen to heat the ground primary magnetic separation sample for hydrogen reduction reaction. The reaction temperature is 1100°C, the reaction time is 1.5 hours, and the reaction gas (hydrogen) flow rate is 700 ml / 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 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 into 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.

[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 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, and 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, thereby obtaining an ilmenite mixture containing elemental iron, and then sintering and crushing the mixture to obtain ilmenite particles;

[0090] In S4, the reaction conditions for obtaining ilmenite particles are as follows: heating the ilmenite powder with a reducing gas at 850°C for a reduction reaction, the reaction time is 13 minutes, the flow rate of the reducing gas is 350 ml / min, and the reducing gas is an inert gas (such as nitrogen) containing 3.5% by volume of hydrogen; finally, the mass percentage of elemental iron in the ilmenite mixture is 6.5%. Then, the ilmenite mixture is sintered in a nitrogen atmosphere at 1100°C for 0.8 hours, and the ilmenite particles with a particle size of 60 μm are obtained by taking out and crushing.

[0091] This scheme 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 surfaces of other components, and cannot form particles separately, 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 surfaces of other components, changing the electromagnetic characteristics of other components, which is not conducive to the research and experiment 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, and then tableting, and then sintering 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, and then 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 850r / min, and the wet mixing time is 1.5h; 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.

[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 sieved using a multi-stage sieve, and the simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain the simulated lunar soil.

[0096] Specifically, the mixed sintered samples were crushed by a blade-type rotary crusher (FB-500) at a speed of 10,000 r / min and a crushing fineness of less than 1 mm. During the crushing process, the samples were randomly crushed into amorphous and angular particles. The samples were sieved by 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.

[0097] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0098] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary 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 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 for hydrogen reduction reaction, while 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 the silicate minerals olivine and pyroxene are reduced to a low degree, to obtain hydrogen reduction products; S3, performing secondary magnetic separation on the hydrogen reduction product to remove elemental iron in S2, and drying the sample after iron removal to obtain a secondary magnetic separation sample for standby use; S4, mixing the ilmenite powder with a reducing gas to react, obtaining an ilmenite mixture containing elemental iron, and then sintering and crushing to obtain ilmenite particles; S5, mixing the secondary magnetic separation sample obtained in S4 and the ilmenite particles obtained in S5 according to a preset mass ratio, and then tableting, and then sintering in an inert atmosphere to obtain a mixed sintered sample; S6. Crushing the mixed sintered sample to obtain simulated lunar soil particles.

2. A 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. A 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 heat the ground primary magnetic separation sample for hydrogen reduction reaction. 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. A 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. A 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 for reduction reaction at 750° C. to 850° C., 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. A 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. A method for preparing simulated lunar soil suitable for resource utilization according to claim 1, characterized in that: In S4, ilmenite particles are then 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; 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.

9. A 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 r / min to 850 r / min, and the wet mixing time is 1.5 h to 2.5 h; The pressed sample is placed in a vacuum sintering furnace for sintering in an inert atmosphere, and after cooling in an inert atmosphere, a mixed sintered sample is obtained.

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 sieved using a multi-stage sieve, and the simulated lunar soil particles of different particle sizes are mixed according to the actual lunar soil particle size composition ratio to obtain the simulated lunar soil.

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