Lunar soil building material, preparation method and application

Abstract

The application relates to a lunar soil building material, a preparation method and application, wherein the preparation method of the lunar soil building material comprises the following steps: S1, simulating lunar soil raw materials to be pressed into lunar soil bricks; S2, adopting hot field and microwave synchronous heating to sinter the lunar soil bricks, and stopping heating, and then cooling to room temperature with a furnace to obtain the lunar soil building material. The method has the beneficial effects that the mechanical properties and appearance quality of the lunar soil building material are improved, production energy consumption is reduced, and a solid technical foundation is provided for low-carbon and high-efficiency construction of a moon base.

Description

Technical Field

[0001] This invention relates to the field of lunar soil building material preparation technology, and in particular to a lunar soil building material, its preparation method, and its application. Background Technology

[0002] Establishing permanent habitats and scientific stations on the Moon is a long-term vision that will benefit all of humanity. During lunar exploration and development, personnel and equipment need protection from the harsh lunar environment, such as ultra-high vacuum, cosmic radiation, extreme temperature variations, and dust and meteorite impacts, necessitating the construction of reliable shelters. However, due to the extremely high cost of transporting materials from Earth, the construction of lunar bases requires an in-situ resource utilization strategy, that is, using locally sourced materials, which offers the advantage of high in-situ utilization rates.

[0003] Currently, various preparation methods have been explored for lunar regolith building materials, including hot-pressing sintering, solar sintering, and selective laser melting (SLM). However, existing methods have the following limitations: traditional sintering processes, such as hot-pressing sintering, suffer from uneven heat distribution, leading to insufficient interlayer fusion and high sintering energy consumption; solar sintering has insufficient melting depth, resulting in substandard mechanical properties and poor structural integrity in the prepared lunar regolith building materials; and laser 3D printing has strict requirements on the particle size of the sintered materials. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a lunar soil building material, preparation method and application, which solves the technical problems of substandard mechanical properties, poor structural integrity and high production energy consumption of existing lunar soil building materials.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, embodiments of the present invention provide a method for preparing lunar soil building materials, comprising the following steps:

[0009] S1. The simulated lunar soil material is pressed into a mold to form lunar soil brick blanks;

[0010] S2. Lunar soil brick blanks are sintered by simultaneous heating with thermal field and microwave. After heating is stopped, the blanks are cooled to room temperature in the furnace to obtain lunar soil building materials.

[0011] As a preferred embodiment of the present invention, in the method for preparing lunar soil building materials, in S1, simulated lunar soil raw materials are poured into the mold in layers from bottom to top;

[0012] Each layer of simulated lunar soil material is laid out and compacted to form a compacted layer.

[0013] As a preferred embodiment of the present invention, in the method for preparing lunar soil building materials, in S1, the upper surface of each layer is roughened before the next layer is laid;

[0014] After being poured into the mold in layers, the multiple layers are then compacted a second time to form lunar soil brick blanks;

[0015] The thickness of the compaction layer is 1-3cm, and the compaction pressure range is 1-5kN.

[0016] In a preferred embodiment of the present invention, in the method for preparing lunar soil building materials, S1, the pressure range of secondary compaction is 600-700kN.

[0017] In a preferred embodiment of the present invention, in the method for preparing lunar soil building materials, S2, when the lunar soil brick blank is sintered by simultaneous heating of the thermal field and microwave, the thermal field temperature range is 900-1100℃, the thermal field heating rate is 7-9℃ / min, the microwave power range is 400-600w, and the heat preservation sintering time is 10-30min.

[0018] In a preferred embodiment of the present invention, in the method for preparing lunar soil building materials, the microwave radiation frequency in step S2 is 2-3 GHz.

[0019] In a preferred embodiment of the present invention, in the method for preparing lunar soil building materials, the microwave radiation frequency in step S2 is 2.45-2.5 GHz.

[0020] Secondly, embodiments of the present invention provide a lunar soil building material, which is prepared using the method for preparing lunar soil building materials.

[0021] Thirdly, embodiments of the present invention provide a method for preparing the lunar soil building material, or the application of the lunar soil building material in in-situ construction of a lunar base.

[0022] (III) Beneficial Effects

[0023] The beneficial effects of this invention are as follows: This invention provides a lunar soil building material, its preparation method, and its application. It utilizes a combined thermal field-microwave sintering process for lunar soil bricks. Microwave sintering employs a specific microwave band, generating heat through electromagnetic field-induced dielectric loss. Furthermore, leveraging the strong penetration and rapid diffusion characteristics of microwaves, microwave sintering can effectively penetrate the sample, rapidly increasing the core temperature and allowing heat to radiate outwards. Simultaneously, an external heat source continuously heats the sample surface, ensuring a stable temperature transition. Through the synergistic effect of internal microwave heating and external thermal field heating, the lunar soil material is heated simultaneously from the inside and surface, significantly improving the density of the lunar soil bricks and reducing porosity, resulting in a more compact and robust structure. Lunar soil bricks sintered using this process can be rapidly formed, exhibiting significantly improved compressive strength and a more uniform microstructure, thus enhancing the overall mechanical properties and structural stability of the lunar soil building material.

[0024] The combination of microwave and thermal field heating enables the entire sample to be heated uniformly, shortens the sintering time, and improves the heat utilization efficiency, thus possessing excellent energy-saving advantages.

[0025] The combined hot-field and microwave sintering technology enables in-situ utilization of lunar resources. Furthermore, the required equipment only integrates heating and microwave technologies, making it feasible. By producing lunar soil building materials using lunar resources, dependence on Earth for supplies can be significantly reduced, achieving self-sufficiency and sustainable development for lunar base construction.

[0026] Compared to existing technologies, it can improve the mechanical properties and appearance quality of lunar soil building materials, while reducing production energy consumption, providing a solid technical foundation for the low-carbon and efficient construction of lunar bases. Attached Figure Description

[0027] Figure 1 Image of the lunar soil brick prepared in Example 1 of this invention;

[0028] Figure 2 Image of lunar soil bricks prepared in Comparative Example 2 of this invention;

[0029] Figure 3 Image of lunar soil brick prepared in Comparative Example 3 of this invention;

[0030] Figure 4 Image of lunar soil bricks prepared with microwave power exceeding 600W in this invention;

[0031] Figure 5 This is a comparison chart of the compressive strength and energy consumption of lunar soil bricks prepared in the embodiments and comparative examples of this invention. Detailed Implementation

[0032] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0033] It should be noted that, for the sake of experimental convenience, simulated lunar soil is used in the following embodiments to further describe the present invention in detail. The mass percentages of the main chemical components of lunar soil and simulated lunar soil were detected by X-ray fluorescence (XRF), as shown in Table 1. The simulated lunar soil was a self-prepared material, and its main chemical components were formulated with reference to the main components of lunar soil (specifically, the main components of Apollo 14 lunar soil). The simulated lunar soil column represents the lunar soil components used in subsequent embodiments. Furthermore, the "Simulated Lunar Soil Range" column in Table 1 provides the range of usable main components for the simulated lunar soil.

[0034] Table 1: Main chemical components of lunar soil and simulated lunar soil

[0035]

[0036] Example 1:

[0037] This embodiment provides a method for preparing lunar soil building materials, specifically including the following steps:

[0038] (1) The simulated lunar soil material (commercially available product, referred to as lunar soil material below) is filled into the mold, and the layers are filled and compacted by manual tamping or hammering. Each layer is 1 cm thick. After each layer is compacted, the surface is roughened to enhance the bonding force between it and the next layer. The above filling, compaction and surface roughening operations are repeated until the mold is full to ensure that each material layer is evenly distributed and has no obvious pores. The mold used is a thickened mold made of all steel.

[0039] (2) Place the mold filled with lunar soil material on the worktable of the press, apply 650kN pressure to the lunar soil material for secondary compaction and molding, maintain the pressure for a moment and then slowly release the pressure to obtain a dense and dimensionally stable lunar soil brick blank.

[0040] (3) Remove the lunar soil brick blanks from the mold to avoid damage during transportation; place 5 lunar soil brick blanks into the sintering chamber of the hot field-microwave combined sintering device, each lunar soil brick blank weighing 200g; start the sintering device to perform hot field-microwave combined heating sintering of the lunar soil brick blanks at a hot field temperature of 960℃, a microwave power of 500w, a microwave radiation frequency of 2.45, a sintering time of 30min, and a heating rate of 8.33℃ / min;

[0041] (4) After heating is stopped, the furnace is cooled to room temperature to obtain lunar soil bricks.

[0042] Performance testing:

[0043] 1. Using prepared lunar soil bricks (see...) Figure 1 According to ASTM C349, compressive strength was tested: three lunar soil brick specimens were selected for compressive strength testing, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0044] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0045] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0046] Example 2:

[0047] This embodiment provides a method for preparing lunar soil building materials. The difference between this embodiment and Embodiment 1 is that:

[0048] Step (3) Remove the lunar soil brick blank from the mold to avoid damage during transportation; place the removed lunar soil brick blank into the sintering chamber of the hot field-microwave combined sintering device; start the sintering device to perform hot field-microwave synergistic heating sintering on the lunar soil brick blank at a hot field temperature of 1100℃, a microwave power of 400w, a sintering time of 30min, and a heating rate of 8.33℃ / min.

[0049] The remaining steps are the same.

[0050] Performance testing:

[0051] 1. The prepared lunar soil bricks were subjected to compressive strength tests according to ASTM C349: Three lunar soil brick specimens were selected for compressive strength tests, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0052] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0053] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0054] Example 3:

[0055] This embodiment provides a method for preparing lunar soil building materials. The difference between this embodiment and Embodiment 1 is that:

[0056] Step (3) Remove the lunar soil brick blank from the mold to avoid damage during transportation; place the removed lunar soil brick blank into the sintering chamber of the hot field-microwave combined sintering device; start the sintering device to perform hot field-microwave synergistic heating sintering on the lunar soil brick blank at a hot field temperature of 900℃, a microwave power of 600w, a sintering time of 30min, and a heating rate of 8.33℃ / min.

[0057] The remaining steps are the same.

[0058] Performance testing:

[0059] 1. The prepared lunar soil bricks were subjected to compressive strength tests according to ASTM C349: Three lunar soil brick specimens were selected for compressive strength tests, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0060] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0061] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0062] Example 4:

[0063] This embodiment provides a method for preparing lunar soil building materials. The difference between this embodiment and Embodiment 1 is that:

[0064] Step (3) Remove the lunar soil brick blank from the mold to avoid damage during transportation; place the removed lunar soil brick blank into the sintering chamber of the hot field-microwave combined sintering device; start the sintering device to perform hot field-microwave synergistic heating sintering on the lunar soil brick blank at a hot field temperature of 960℃, a microwave power of 500w, a sintering time of 10min, and a heating rate of 8.33℃ / min.

[0065] The remaining steps are the same.

[0066] Performance testing:

[0067] 1. The prepared lunar soil bricks were subjected to compressive strength tests according to ASTM C349: Three lunar soil brick specimens were selected for compressive strength tests, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0068] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0069] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0070] Example 5:

[0071] This embodiment provides a method for preparing lunar soil building materials. The difference between this embodiment and Embodiment 1 is that:

[0072] Step (3) Remove the lunar soil brick blank from the mold to avoid damage during transportation; place the removed lunar soil brick blank into the sintering chamber of the hot field-microwave combined sintering device; start the sintering device to perform hot field-microwave synergistic heating sintering on the lunar soil brick blank at a hot field temperature of 900℃, a microwave power of 500w, a sintering time of 30min, and a heating rate of 8.33℃ / min.

[0073] The remaining steps are the same.

[0074] Performance testing:

[0075] 1. The prepared lunar soil bricks were subjected to compressive strength tests according to ASTM C349: Three lunar soil brick specimens were selected for compressive strength tests, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0076] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0077] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing lunar soil building materials. The difference between this comparative example and Example 1 is that:

[0080] In step (3), a single hot field heating sintering is used, the sintering hot field temperature is 960℃, the sintering time is 90min, and the heating rate is 8.33℃ / min;

[0081] The remaining steps are the same.

[0082] Performance testing:

[0083] 1. The prepared lunar soil bricks were subjected to compressive strength tests according to ASTM C349: Three lunar soil brick specimens were selected for compressive strength tests, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0084] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0085] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0086] Comparative Example 2

[0087] This comparative example provides a method for preparing lunar soil building materials. The difference between this comparative example and Example 1 is that:

[0088] In step (3), single microwave heating sintering is used, with a microwave power of 500w, a sintering time of 30min, and a heating rate of 8.33℃ / min;

[0089] The remaining steps are the same.

[0090] Performance testing:

[0091] 1. Using prepared lunar soil bricks (see...) Figure 2 According to ASTM C349, compressive strength was tested: three lunar soil brick specimens were selected for compressive strength testing, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0092] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0093] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0094] Comparative Example 3

[0095] This comparative example provides a method for preparing lunar soil building materials. The difference between this comparative example and Example 3 is that:

[0096] In step (3), the microwave power is reduced to 220W;

[0097] The remaining steps are the same.

[0098] Performance testing:

[0099] 1. Using prepared lunar soil bricks (see...) Figure 3 According to ASTM C349, compressive strength was tested: three lunar soil brick specimens were selected for compressive strength testing, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0100] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0101] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0102] Comparative Example 4

[0103] This comparative example provides a method for preparing lunar soil building materials. The difference between this comparative example and Example 3 is that:

[0104] In step (3), the microwave power is reduced to 300W;

[0105] The remaining steps are the same.

[0106] Performance testing:

[0107] 1. The prepared lunar soil bricks were subjected to compressive strength tests according to ASTM C349: Three lunar soil brick specimens were selected for compressive strength tests, and the average value of the measured compressive strength was taken as the compressive strength value of the lunar soil brick, as detailed in Table 2.

[0108] 2. The sintering energy consumption of step (3) was tested, and the test results are detailed in Table 3.

[0109] 3. The porosity of lunar soil bricks was determined by the mercury intrusion method according to standard GB / T 21650.1-2008. The test results are detailed in Table 4.

[0110] Table 2: Compressive strength of lunar soil bricks

[0111]

[0112] Table 3: Energy Consumption Value Test Results

[0113]

[0114] Table 4: Porosity Test Results

[0115]

[0116] For ease of analysis, the sintering process parameters of step (3) in the above embodiments and comparative examples are summarized in Table 5:

[0117] Table 5: Sintering Process Parameters

[0118]

[0119] Referring to the above embodiments and comparative examples, the analysis is as follows:

[0120] Considering both the performance of lunar soil bricks (compressive strength and porosity) and sintering energy consumption, Example 1 is selected as the preferred embodiment of this invention. See also... Figure 1 The lunar soil bricks prepared in Example 1 have a dense surface and a reddish color.

[0121] Comparing Comparative Example 1 with Example 1, it can be seen that even with extended heating time (increased energy consumption), the compressive strength of the lunar soil bricks sintered in Comparative Example 1 using only thermal field heating is still significantly lower than that of the lunar soil bricks prepared in Example 1, while the porosity of the lunar soil bricks sintered in Comparative Example 1 is significantly higher than that of Example 1. This indicates that the combined thermal field and microwave process in Example 1 can both reduce sintering energy consumption and significantly improve the mechanical properties and appearance quality of the lunar soil bricks.

[0122] Comparing Comparative Example 2 with Example 1, it can be seen that although the sintering process using microwave heating alone has low energy consumption, the compressive strength of the corresponding lunar soil bricks is only 1.9 MPa. See also... Figure 2 and Figure 1 The lunar soil bricks prepared in Comparative Example 2 were whitish in color, with little color variation.

[0123] In addition, based on Comparative Example 2, without changing the sintering time, an experiment was conducted to increase the microwave power to 700W (exceeding 600W). The prepared lunar soil bricks are shown below. Figure 4 As shown: Excessive microwave heating triggers localized thermal runaway. High-dielectric-loss phases such as iron- and titanium-rich phases in the lunar regolith preferentially absorb microwaves and heat up inside the lunar regolith brick blank. At the hot spot, these phases soften or partially melt, generating a Fe-rich silicate liquid phase. This liquid phase coalesces into droplets within pores or locally dense areas, and rapidly vitrifies upon cooling after shutdown, ultimately leaving behind shiny, hemispherical "molten beads" inside. Furthermore, the microwave heating method alone results in a much higher temperature at the center of the lunar regolith brick blank compared to the outer layer, creating a huge temperature difference between the inside and outside and asynchronous sintering and densification. The hot spot area melts and shrinks first, while the surrounding area remains loose and at a lower temperature, forming strong constraints. Ultimately, this mismatch between thermal stress and shrinkage leads to cracking.

[0124] A comparison of Examples 1 and 4 shows that the compressive strength of the lunar soil brick prepared in Example 1 of the present invention is higher than that in Comparative Example 4, and the porosity of the lunar soil brick prepared in Example 1 of the present invention is lower than that in Comparative Example 4. This indicates that appropriately extending the sintering time can significantly improve the compressive strength of the lunar soil brick and control the porosity.

[0125] A comparison of Examples 1 and 5 shows that the compressive strength of the lunar soil bricks prepared in Example 1 is higher than that in Example 5, indicating that appropriately increasing the temperature of the thermal field under the synergistic effect of microwaves is beneficial to improving the compressive strength and reducing the porosity of the lunar soil bricks.

[0126] A comparison of Examples 3 and 5 shows that when the thermal field temperature is relatively low, increasing the microwave power has little effect on optimizing the compressive strength and porosity of lunar soil bricks. Combined with Example 2, this indirectly reflects that when the thermal field and microwave are combined, changes in the thermal field temperature have a greater effect on controlling the compressive strength and porosity of lunar soil bricks.

[0127] A comparison of Examples 1 to 5 with Comparative Examples 3 and 4 shows that when the microwave power is below 400W, it affects the compressive strength and porosity of lunar soil bricks. (See [link to relevant documentation]). Figure 3 (Comparative Example 3) Cracks appeared in the fired lunar soil bricks.

[0128] See Figure 5 The energy consumption and compressive strength of lunar soil bricks of all embodiments and comparative examples are shown. Embodiments 1, 3, 4, and 5 significantly reduce energy consumption compared to comparative example 1 while maintaining compressive strength and porosity.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing lunar soil building materials, characterized in that, Includes the following steps: S1. The simulated lunar soil material is pressed into a mold to form lunar soil brick blanks; S2. Lunar soil brick blanks are sintered by simultaneous heating with thermal field and microwave. After heating is stopped, the blanks are cooled to room temperature in the furnace to obtain lunar soil building materials.

2. The method for preparing lunar soil building materials as described in claim 1, characterized in that, In S1, the simulated lunar soil material is poured into the mold in layers from bottom to top; Each layer of simulated lunar soil material is laid out and compacted to form a compacted layer.

3. The method for preparing lunar soil building materials as described in claim 2, characterized in that, In S1, the upper surface of each layer is roughened before the next layer is laid; After being poured into the mold in layers, the multiple layers are then compacted a second time to form lunar soil brick blanks; The thickness of the compaction layer is 1-3cm, and the compaction pressure range is 1-5kN.

4. The method for preparing lunar soil building materials as described in claim 3, characterized in that, In S1, the pressure range for secondary compaction is 600-700kN.

5. The method for preparing lunar soil building materials as described in claim 1, characterized in that, In S2, when the lunar soil brick blank is sintered by simultaneous heating of the hot field and microwave, the temperature range of the hot field is 900-1100℃, the heating rate of the hot field is 7-9℃ / min, the microwave power range is 400-600w, and the holding time for sintering is 10-30min.

6. The method for preparing lunar soil building materials as described in claim 5, characterized in that, In S2, the frequency of microwave radiation is 2-3 GHz.

7. The method for preparing lunar soil building materials as described in claim 6, characterized in that, In S2, the frequency of microwave radiation is 2.45-2.5 GHz.

8. A lunar soil building material, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 7.

9. The preparation method according to any one of claims 1 to 7, or the lunar soil building material according to claim 8, in the in-situ construction of a lunar base.

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