A calcium fluoroaluminate modified high-stability supersulfate cement and its application

Abstract

The present invention relates to the technical field of supersulfate cement, and specifically discloses a calcium fluoroaluminate-modified high-stability supersulfate cement and its application. The raw materials of the supersulfate cement include the following components: 70-80 parts by weight of mineral powder, 10-15 parts by weight of gypsum, 5-10 parts by weight of calcium fluoroaluminate, and 1-2 parts by weight of modified diatomaceous earth. The modified diatomaceous earth is porous diatomaceous earth microspheres loaded with L-aspartic acid. The present invention utilizes the synergistic effect of the calcium fluoroaluminate and the modified diatomaceous earth to not only improve the early strength of the supersulfate cement, but also effectively improve the chemical stability of the hydration product ettringite (AFt), thereby improving the carbonation resistance of the supersulfate cement and alleviating the problem of long-term strength shrinkage.

Description

Technical Field

[0001] The present invention relates to the technical field of supersulfate cement, and in particular to calcium fluoroaluminate modified high-stability supersulfate cement and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] my country's annual production of Portland cement clinker has exceeded 2 billion tons for many consecutive years, resulting in significant consumption of natural resources and energy, and CO2 emissions accounting for over 20% of total industrial emissions. Energy conservation and emission reduction in the cement industry are key to its sustainable development. Supersulfated cement (SSC) is a green, low-carbon cement made by grinding and mixing a large amount of aluminosilicate industrial slag, a small amount of activator, and an appropriate amount of gypsum. It breaks away from the traditional "two grinding and one burning" process of Portland cement, and its carbon emissions are only about 10% of traditional Portland cement. It also boasts excellent properties such as low hydration heat, high late strength, and strong resistance to sulfate attack.

[0004] However, the early strength of supersulfated cement is generally low. This is because the slag cannot be effectively activated in the early stage and it is difficult for the slag to quickly dissolve Ca 2+ 、Al 3+ , resulting in the inability to form sufficient cementitious hydration products, leading to very slow early strength development. Furthermore, since the primary hydration products of supersulfated cement are ettringite (AFt) and calcium silicate hydrate (CSH) gel, and the AFt content is much higher than that in ordinary Portland cement, AFt is very unstable and easily carbonized and decomposed by atmospheric carbon dioxide into non-cementitious products such as calcium sulfate and calcium carbonate. This results in significant long-term strength reduction in supersulfated cement, severely restricting its engineering applications. Summary of the Invention

[0005] The present invention provides a calcium fluoroaluminate-modified high-stability supersulfated cement and its application, which not only improves early strength but also effectively enhances the stability of AFt and its carbonation resistance, alleviating the long-term strength shrinkage problem of supersulfated cement. Specifically, the technical solution of the present invention is as follows.

[0006] In a first aspect, the present invention provides a calcium fluoroaluminate-modified high-stability supersulfated cement. The raw materials include the following components: 70-80 parts by weight of mineral powder, 10-15 parts by weight of gypsum, 5-10 parts by weight of calcium fluoroaluminate (11CaO·7Al2O3·CaF2), and 1-2 parts by weight of modified diatomaceous earth. The modified diatomaceous earth is porous diatomaceous earth microspheres loaded with L-aspartic acid.

[0007] Furthermore, the gypsum includes at least one of desulfurized gypsum, phosphogypsum, fluorinated gypsum, titanium gypsum, and chemically pure gypsum.

[0008] Furthermore, the preparation method of the modified diatomite comprises the following steps:

[0009] (1) The porous diatomaceous earth microspheres are treated by impregnation with acid solution, washed to remove the residual acid solution, and then dried to obtain pretreated diatomaceous earth microspheres.

[0010] (2) The pretreated diatomaceous earth microspheres are mixed with the L-aspartic acid solution and allowed to stand for loading. After completion, the solid product is separated and dried to obtain the modified diatomaceous earth.

[0011] Furthermore, in step (1), the particle size of the porous diatomaceous earth microspheres is 15-45 μm.

[0012] Furthermore, in step (1), the acid solution comprises at least one of hydrochloric acid, sulfuric acid, oxalic acid, etc. Optionally, the concentration of the acid solution is 0.1-0.5 mol / L.

[0013] Furthermore, in step (1), the immersion treatment time is 20 to 24 hours, so as to fully remove impurities in the diatomaceous earth microspheres.

[0014] Furthermore, in step (1), the drying temperature is 100-110° C. and the drying time is 3-5 h.

[0015] Furthermore, in step (2), the ratio of the pretreated diatomaceous earth microspheres to the L-aspartic acid solution is 1-2 g: 1-5 ml. Optionally, the mass fraction of the L-aspartic acid solution is 0.12 ~ 0.18%.

[0016] Furthermore, in step (2), the standing time is 3 to 4 hours, so that the L-aspartic acid can be fully loaded into the diatomaceous earth microspheres.

[0017] Furthermore, in step (2), the drying temperature is 40-60° C. and the drying time is 24-48 hours.

[0018] In a second aspect, the present invention provides applications of the calcium fluoroaluminate modified high-stability supersulfate cement in the fields of construction, bridges, roads, water conservancy and hydropower.

[0019] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0020] The supersulfate cement of the present invention utilizes calcium fluoroaluminate to rapidly hydrate to form a cementitious product under the action of mixing water, and can also release a large amount of OH - 、Al(OH)4 - , Ca 2+ The characteristics of the ions significantly increase the pH value of the cement system, destroy the glassy structure of the mineral powder, and increase its hydration activity, thereby improving the early hydration ability of the mineral powder and further improving the early mechanical properties of the supersulfate cement. At the same time, the gelled product formed by the hydration of the calcium fluoroaluminate also helps to improve the early strength, so that the supersulfate cement of the present invention has excellent early mechanical properties. However, the present invention further found that the Al released by the hydration of the calcium fluoroaluminate 3+ Ca easily dissolved in the slag 2+ and SO4 dissolved from gypsum 2- The combination of AFt and the interweaving of a large number of AFt forms a network, causing flash setting, which leads to a rapid loss of fluidity of supersulfated cement, making it difficult to use in practice. To this end, the present invention uses L-aspartic acid modified diatomaceous earth microspheres to effectively overcome the above problem. The reason is that:

[0021] (1) The L-aspartic acid does not rob the Ca in the liquid phase. 2+ , but selectively chelates Al 3+ The characteristics of diatomite microspheres can effectively control the generation rate of AFt, not only avoiding the flash setting phenomenon caused by the rapid formation of a large amount of AFt in a short period of time, but also the controllable and continuous formation of AFt also ensures the early strength of supersulfated cement. At the same time, the porous structure of diatomite microspheres enables the loaded L-aspartic acid to gradually release the chelated Al 3+ , making the formed AFt more stable and effectively alleviating the problem of long-term strength shrinkage. This is because: on the one hand, the modified diatomaceous earth can selectively bind Al by using its L-aspartic acid 3+ The formation of a stable octahedral chelate loaded in the porous diatomite slow-release microspheres reduces the Al content in the system. 3+ concentration, but it has almost no effect on Ca²⁺. As the hydration reaction proceeds, Al 3+ As the concentration decreases, the diatomite slow-release microspheres gradually release Al 3+ Make Al in the system 3+Maintaining stability effectively avoids the flash coagulation caused by explosive nucleation of AFt due to a sudden increase in Al³⁺ concentration in traditional processes. It also ensures uniform growth of AFt crystals at a controllable rate, significantly reducing lattice distortion and vacancy defects. Furthermore, the low-carbon-calcium-silicon ratio CSH gel induced by L-aspartic acid bonds with the sulfate groups of AFt through hydrogen bonds, forming a three-dimensional interlocking network. This significantly increases the activation energy of the AFt to AFm phase transition, significantly suppresses the tendency of crystal decomposition, and improves the stability of AFt.

[0022] (2) The L-aspartic acid can still maintain good selective chelation of Al in the high alkaline environment formed by calcium fluoroaluminate. 3+ This is because L-aspartic acid can form a rigid five-membered ring through the bidentate coordination of its carboxyl group (-COOH) and amino group (-NH2), and upgrade to a three-molecule hexadentate package (α-carboxyl, β-carboxyl and amino) in a highly alkaline environment, effectively avoiding the inability to effectively achieve the above-mentioned selective chelation of Al in a highly alkaline environment. 3+ problem.

[0023] (3) The diatomite microspheres release active silica in the high alkaline environment provided by calcium fluoroaluminate, and the active silica and the Ca2+ dissolved in the slag 2+ The reaction forms CSH gel, which not only improves the mechanical strength of cement, but also densifies the cement matrix and reduces the infiltration of carbon dioxide, thereby improving the carbonation resistance of the super sulfate cement of the present invention. On the other hand, the diatomaceous earth microspheres and the homogeneously grown AFt can synergistically reduce the total porosity of the cement matrix, forming a physical diffusion barrier. In addition, the tortuous microporous path significantly extends the CO2 penetration distance, thereby further improving the carbonation resistance of the super sulfate cement of the present invention. In addition, the modified diatomaceous earth can utilize its L-aspartic acid to induce carbonization products in the form of high-density aragonite phase calcium carbonate, and its dense structure helps to inhibit the expansion of microcracks. At the same time, the free aluminum ions and the silica gel generated by carbonization are cross-linked to form an aluminosilicate reinforcing phase, which can significantly improve the mechanical properties of the super sulfate cement of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute a part of the present invention, are used to provide further understanding of the present invention and are not intended to constitute an improper limitation of the present invention.

[0025] Figure 1 This is a sample picture of modified diatomaceous earth prepared in the following Example 1.

[0026] Figure 2 This is a 28d compressive strength test diagram of the following Example 1.

[0027] Figure 3 This is a sample of modified diatomaceous earth prepared in Example 2 below.

[0028] Figure 4 This is a 28d compressive strength test diagram of the following Example 2.

[0029] Figure 5 This is a sample of modified diatomaceous earth prepared in Example 3 below.

[0030] Figure 6 This is a 28d compressive strength test diagram of the following Example 3. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Unless otherwise defined, all professional and scientific terms used in the present invention have the same meanings as those familiar to those skilled in the art. The preferred implementation methods and materials described in the present invention are for exemplary purposes only. The technical solutions of the present invention will now be further described with reference to specific embodiments.

[0032] Example 1:

[0033] A method for preparing calcium fluoroaluminate modified high-stability supersulfated cement comprises the following steps:

[0034] (1) Porous diatomite microspheres with a particle size distribution between 15 and 45 μm were soaked in 0.1 mol / L hydrochloric acid for 24 h, then washed with deionized water until neutral. The microspheres were then vacuum dried at 100°C (vacuum degree -0.08 MPa) for 5 h to obtain pretreated diatomite microspheres for later use.

[0035] (2) The pretreated diatomite microspheres were mixed with a 0.15% L-aspartic acid aqueous solution at a ratio of 1.5 g: 3 ml and allowed to stand for 3 hours. After completion, the solid product was filtered out and vacuum dried at 50 ° C (vacuum degree -0.08 MPa) for 36 hours to obtain modified diatomite (such as Figure 1 as shown), and keep it as a standby.

[0036] (3) Weigh the following raw materials in the following proportions: 74 parts by weight of mineral powder, 12 parts by weight of desulfurized gypsum powder, 9 parts by weight of calcium fluoroaluminate powder, and 1.5 parts by weight of the modified diatomaceous earth of this example. Mix the above raw materials and grind them at 300 r / min for 10 min. Then, add 0.4 times the weight of mixing water to the resulting mixture. Slowly stir at 500 r / min for 120 s, then pause for 15 s, and then rapidly stir at 1000 r / min for 120 s to obtain supersulfate cement slurry.

[0037] Performance test: 1. The super sulfate cement slurry prepared in this embodiment was poured into a mold, vibrated and cured for 1 day before demoulding, and then continued to be cured for 1 day, 3 days, and 28 days (the curing temperature was set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimens (such as Figure 2 2. The setting time of the supersulfate cement slurry prepared in this example was tested according to the "Test Method for Water Consumption, Setting Time and Soundness of Cement at Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the following table.

[0038]

[0039] Example 2:

[0040] A method for preparing calcium fluoroaluminate modified high-stability supersulfated cement comprises the following steps:

[0041] (1) Porous diatomite microspheres with a particle size distribution between 15 and 45 μm were immersed in 0.3 mol / L sulfuric acid for 22 h, then washed with deionized water until neutral. The microspheres were then vacuum dried at 110°C (vacuum degree -0.08 MPa) for 3 h to obtain pretreated diatomite microspheres for later use.

[0042] (2) The pretreated diatomite microspheres were mixed with a 0.12% L-aspartic acid aqueous solution at a ratio of 1 g: 1 ml and allowed to stand for 4 hours. After the mixture was completed, the solid product was filtered out and vacuum dried at 40°C (vacuum degree -0.08 MPa) for 48 hours to obtain modified diatomite (such as Figure 3 as shown), and keep it as a standby.

[0043] (3) Weigh the following raw materials in the following proportions: 80 parts by weight of mineral powder, 15 parts by weight of phosphogypsum powder, 10 parts by weight of calcium fluoroaluminate powder, and 2 parts by weight of the modified diatomite of this example. Mix the above raw materials and grind them at 300 r / min for 10 min. Then, add 0.41 times the weight of mixing water to the resulting mixture and slowly stir at 500 r / min for 120 s, then pause for 15 s, and then rapidly stir at 1000 r / min for 120 s to obtain supersulfate cement slurry.

[0044] Performance test: 1. The super sulfate cement slurry prepared in this embodiment was poured into a mold, vibrated and cured for 1 day before demoulding, and then continued to be cured for 1 day, 3 days, and 28 days (the curing temperature was set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimens (such as Figure 4 2. The setting time of the supersulfate cement slurry prepared in this example was tested according to the "Test Method for Water Consumption, Setting Time and Soundness of Cement at Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the following table.

[0045]

[0046] Example 3:

[0047] A method for preparing calcium fluoroaluminate modified high-stability supersulfated cement comprises the following steps:

[0048] (1) Porous diatomite microspheres with a particle size distribution between 15 and 45 μm were immersed in 0.5 mol / L oxalic acid for 20 h, then washed with deionized water until neutral. The microspheres were then vacuum dried at 105°C (vacuum degree -0.08 MPa) for 4 h to obtain pretreated diatomite microspheres for later use.

[0049] (2) The pretreated diatomite microspheres were mixed with a 0.18% L-aspartic acid aqueous solution at a ratio of 2 g: 5 ml and allowed to stand for 3.5 hours. After completion, the solid product was filtered out and vacuum dried at 60 ° C (vacuum degree -0.08 MPa) for 24 hours to obtain modified diatomite (such as Figure 5 as shown), and keep it as a standby.

[0050] (3) Weigh the following raw materials in the following proportions: 70 parts by weight of mineral powder, 10 parts by weight of fluorgypsum powder, 5 parts by weight of calcium fluoroaluminate powder, and 1 part by weight of the modified diatomite of this example. Mix the above raw materials and grind them at 300 r / min for 10 min. Then, add 0.4 times the weight of mixing water to the resulting mixture. Slowly stir at 500 r / min for 120 s, then pause for 15 s, and then rapidly stir at 1000 r / min for 120 s to obtain supersulfate cement slurry.

[0051] Performance test: 1. The super sulfate cement slurry prepared in this embodiment was poured into a mold, vibrated and cured for 1 day before demoulding, and then continued to be cured for 1 day, 3 days, and 28 days (the curing temperature was set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimens (such as Figure 6 2. The setting time of the supersulfate cement slurry prepared in this example was tested according to the "Test Method for Water Consumption, Setting Time and Soundness of Cement at Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the following table.

[0052]

[0053] Example 4:

[0054] A method for preparing supersulfate cement comprises the following steps:

[0055] Weigh the following raw materials in the following proportions: 74 parts by weight of mineral powder, 12 parts by weight of desulfurized gypsum powder, 9 parts by weight of calcium fluoroaluminate powder, and 0.2 parts by weight of citric acid. Mix these raw materials and grind them at 300 r / min for 10 minutes. Then, add 0.4 times the weight of mixing water to the resulting mixture. Slowly stir at 500 r / min for 120 seconds, then pause for 15 seconds, and then rapidly stir at 1000 r / min for 120 seconds to produce supersulfated cement slurry.

[0056] Performance test: 1. The super sulfate cement slurry prepared in this embodiment is poured into a mold, vibrated and cured for 1 day before demoulding, and then continued to be cured until the age of 1d, 3d, and 28d (the curing temperature is set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimen is tested according to the "Test Method for Strength of Cement Mortar (ISO Method)" (GBT 17671-2021). 2. The setting time of the super sulfate cement slurry prepared in this embodiment is tested according to the "Test Method for Water Consumption, Setting Time and Stability of Cement Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the table below. It can be seen that although traditional citric acid can prolong the setting time of super sulfate cement as a retarder, it will also cause a significant loss of strength. This is because citric acid will rob Ca in the liquid phase 2+ , inhibiting the formation of CSH gel, and at the same time causing the formed AFt to be easily carbonized and decomposed, resulting in the deterioration of the long-term strength of supersulfated cement.

[0057]

[0058] Example 5:

[0059] A method for preparing supersulfate cement comprises the following steps:

[0060] Weigh the following raw materials in the following proportions: 74 parts by weight of mineral powder, 12 parts by weight of desulfurized gypsum powder, and 9 parts by weight of calcium fluoroaluminate powder. Mix these raw materials and grind them at 300 r / min for 10 minutes. Then, add 0.4 times the weight of mixing water to the resulting mixture. Slowly stir at 500 r / min for 120 seconds, then pause for 15 seconds, and then rapidly stir at 1000 r / min for 120 seconds to produce supersulfated cement slurry.

[0061] Performance test: 1. The super sulfate cement slurry prepared in this embodiment was poured into a mold, vibrated and cured for 1 day before demolding, and then continued to be cured to the age of 1d, 3d, and 28d (the curing temperature was set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimen was tested according to the "Test Method for Strength of Cement Mortar (ISO Method)" (GBT 17671-2021). 2. The setting time of the super sulfate cement slurry prepared in this embodiment was tested according to the "Test Method for Water Consumption, Setting Time and Soundness of Cement Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the table below. It can be seen that due to the lack of the addition of modified diatomaceous earth, the super sulfate cement prepared in this embodiment not only showed obvious flash setting, but also had significantly lower strength.

[0062]

[0063] Example 6:

[0064] A method for preparing supersulfate cement comprises the following steps:

[0065] (1) Porous diatomaceous earth microspheres with a particle size distribution between 15 and 45 μm were immersed in 0.3 mol / L sulfuric acid for 22 h, then washed with deionized water until neutral and vacuum dried at 110 °C (vacuum degree -0.08 MPa) for 3 h to obtain pretreated diatomaceous earth microspheres for later use.

[0066] (2) Weigh the following raw materials in the following proportions: 80 parts by weight of mineral powder, 15 parts by weight of phosphogypsum powder, 10 parts by weight of calcium fluoroaluminate powder, and 2 parts by weight of the pretreated diatomaceous earth microspheres of this example. Mix the above raw materials and grind them at a rate of 300 r / min for 10 min. Then, add 0.41 times the weight of mixing water to the resulting mixture and slowly stir at a rate of 500 r / min for 120 s, then pause for 15 s, and then rapidly stir at a rate of 1000 r / min for 120 s to obtain supersulfate cement slurry.

[0067] Performance test: 1. The supersulfate cement slurry prepared in this embodiment was poured into a mold, vibrated and cured for 1 day before demolding, and then continued to be cured until the age of 1d, 3d, and 28d (the curing temperature was set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimen was tested according to the "Test Method for Strength of Cement Mortar (ISO Method)" (GBT 17671-2021). 2. The setting time of the supersulfate cement slurry prepared in this embodiment was tested according to the "Test Method for Water Consumption, Setting Time and Soundness of Cement Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the table below. It can be seen that when the diatomaceous earth is not modified with L-aspartic acid, the supersulfate cement prepared in this embodiment shows obvious flash setting phenomenon, and the compressive strength is significantly reduced.

[0068]

[0069] Example 7:

[0070] A method for preparing supersulfate cement comprises the following steps:

[0071] (1) Porous diatomite microspheres with a particle size distribution between 15 and 45 μm were immersed in 0.5 mol / L oxalic acid for 20 h, then washed with deionized water until neutral. The microspheres were then vacuum dried at 105°C (vacuum degree -0.08 MPa) for 4 h to obtain pretreated diatomite microspheres for later use.

[0072] (2) The pretreated diatomaceous earth microspheres were mixed with a 0.18% L-aspartic acid aqueous solution at a ratio of 2 g:5 ml and allowed to stand for 3.5 hours. After completion, the solid product was filtered out and vacuum dried at 60°C (vacuum degree -0.08 MPa) for 24 hours to obtain modified diatomaceous earth for later use.

[0073] (3) Weigh the following raw materials in the following proportions: 70 parts by weight of mineral powder, 10 parts by weight of fluorgypsum powder, and 1 part by weight of the modified diatomaceous earth of this example. Mix the raw materials and grind them at 300 r / min for 10 min. Then, add 0.4 times the weight of mixing water to the resulting mixture. Slowly stir at 500 r / min for 120 s, then pause for 15 s, and then rapidly stir at 1000 r / min for 120 s to obtain supersulfate cement slurry.

[0074] Performance test: 1. The supersulfate cement slurry prepared in this embodiment was poured into a mold, vibrated and cured for 1 day before demolding, and then continued to be cured to the age of 1d, 3d, and 28d (the curing temperature was set to (20±3°C, relative humidity ≥95%), and the compressive strength of the specimen was tested according to the "Test Method for Strength of Cement Mortar (ISO Method)" (GBT 17671-2021). 2. The setting time of the supersulfate cement slurry prepared in this embodiment was tested according to the "Test Method for Water Consumption, Setting Time and Soundness of Cement Standard Consistency" (GB / T 1346-2024). The test results of the above performance indicators are shown in the table below. It can be seen that since calcium fluoroaluminate was not added, the supersulfate cement in this embodiment has slow hydration, the setting time is significantly increased, and the early strength is significantly reduced.

[0075]

[0076] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that they may modify the technical solutions described in the foregoing embodiments or substitute equivalents for some of the technical features. Any such modifications, equivalent substitutions, and improvements shall be within the scope of protection of the present invention.

Claims

1. A calcium fluoroaluminate modified high-stability supersulfate cement, characterized in that: The raw materials include the following components: 70-80 parts by weight of mineral powder, 10-15 parts by weight of gypsum, 5-10 parts by weight of calcium fluoroaluminate, and 1-2 parts by weight of modified diatomaceous earth; the modified diatomaceous earth is porous diatomaceous earth microspheres loaded with L-aspartic acid.

2. The calcium fluoroaluminate modified high-stability supersulfated cement according to claim 1, characterized in that The preparation method of the modified diatomaceous earth comprises the following steps: (1) The porous diatomite microspheres are treated by impregnation with an acid solution, washed to remove the residual acid solution, and then dried to obtain pretreated diatomite microspheres; (2) The pretreated diatomaceous earth microspheres are mixed with the L-aspartic acid solution and allowed to stand for loading. After completion, the solid product is separated and dried to obtain the modified diatomaceous earth.

3. The calcium fluoroaluminate modified high-stability supersulfated cement according to claim 2, characterized in that: In step (1), the particle size of the porous diatomaceous earth microspheres is 15-45 μm.

4. The calcium fluoroaluminate modified high-stability supersulfated cement according to claim 2, characterized in that: In step (1), the acid solution includes at least one of hydrochloric acid, sulfuric acid, and oxalic acid; or, in step (1), the concentration of the acid solution is 0.1-0.5 mol / L.

5. The calcium fluoroaluminate modified high-stability supersulfated cement according to claim 2, characterized in that: In step (1), the immersion treatment time is 20 to 24 hours.

6. The calcium fluoroaluminate modified high-stability supersulfated cement according to claim 2, characterized in that: In step (2), the ratio of the pretreated diatomaceous earth microspheres to the L-aspartic acid solution is 1-2 g: 1-5 ml; or the mass fraction of the L-aspartic acid solution is 0.12 ~ 0.18%.

7. The calcium fluoroaluminate modified high-stability supersulfated cement according to claim 2, characterized in that: In step (2), the standing time is 3 to 4 hours.

8. The calcium fluoroaluminate modified high-stability supersulfated cement according to any one of claims 2 to 7, characterized in that: In step (1), the drying temperature is 100-110° C. and the drying time is 3-5 h; or, in step (2), the drying temperature is 40-60° C. and the drying time is 24-48 h.

9. The calcium fluoroaluminate modified high-stability supersulfated cement according to any one of claims 1 to 7, characterized in that: The gypsum includes at least one of desulfurized gypsum, phosphogypsum, fluorinated gypsum, titanium gypsum, and chemically pure gypsum.

10. Use of the calcium fluoroaluminate modified high-stability supersulfated cement according to any one of claims 1 to 9 in the fields of construction, bridges, roads, or water conservancy and hydropower.

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