Low-carbon corrosion-resistant composite cement and preparation method thereof

Abstract

The present invention provides a low-carbon, corrosion-resistant composite cement and a preparation method thereof. In the pretreatment process of ordinary silicate and high-silicon, iron-rich phase low-carbon, corrosion-resistant cement clinker, the present invention makes the main distribution intervals of different cement clinkers concentrate in the corresponding intervals of the grading model according to the characteristics of the raw materials to achieve a tight stacking effect, and at the same time makes the hydration intervals of silicon phase minerals and aluminum phase minerals match, promotes more aluminum ions to enter the gel, optimizes the gel structure, reduces the amount of clinker used, and improves the overall mechanical properties and durability of the material. The present invention also improves the hydration degree of auxiliary cementitious materials and optimizes the pore structure through the synergistic excitation effect between the composite strengthener and the cement hydration product, further matches the hydration intervals of silicon phase minerals and aluminum phase minerals, reduces the amount of cement clinker used, and increases the amount of auxiliary cementitious materials such as building recycled micropowder, further achieving the effect of carbon reduction and emission reduction.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a low-carbon corrosion-resistant composite cement and a preparation method thereof. Background Art

[0002] With the rapid development of my country's marine economy and the implementation of major coastal construction projects, the demand for marine concrete has increased annually. As a country with the largest number of tunnels, the largest construction scale, and the fastest growth in the world, the long-life design of submarine tunnels in high-water pressure and high-chloride environments has become a research focus in my country in recent years. Furthermore, guided by the national strategy of "carbon peak and carbon neutrality," my country is in the midst of a critical juncture in its transition to a low-carbon energy source. It is estimated that carbon emissions from my country's cement and concrete industry account for 11% of the country's total carbon emissions, and cement and concrete production is the primary source of carbon emissions, necessitating urgent carbon reduction and emission reduction. In summary, traditional materials cannot meet the dual requirements of low carbonization and long life for marine concrete in my country. Consequently, low-carbon, corrosion-resistant cementitious materials have become a research hotspot.

[0003] Using industrial solid waste with potential cementitious activity to replace traditional cement in the preparation of composite cement not only improves solid waste utilization but also reduces material costs, making it an important means of reducing carbon emissions in concrete materials. Furthermore, with economic development and advancing urbanization, China's construction waste output was estimated to be approximately 30 million tons in 2020. Incorporating recycled construction materials into the preparation of composite cement not only avoids the landfilling of waste concrete but also reduces transportation distances and allows for carbon absorption during storage, resulting in excellent carbon reduction capabilities. However, excessive incorporation of solid wastes such as recycled construction powder, blast furnace slag, and fly ash can compromise the performance of composite cement. Methods and measures are needed to increase the maximum incorporation rate of solid waste while ensuring target performance. Therefore, further research is needed on the collaborative preparation of low-carbon cementitious materials under multiple objectives. Summary of the Invention

[0004] The main technical problem solved by the present invention is to provide a low-carbon corrosion-resistant composite cement. The low-carbon corrosion-resistant composite cement prepared by the present invention has a 1d compressive strength of ≥32.6MPa, a 28d compressive strength of ≥58.4MPa, and a 28d chloride ion diffusion coefficient of 0.54×10 -12 m 2 / s, 180d seawater corrosion resistance coefficient K 180 ≥1.10, and has stronger ability to resist deformation.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention proposes a low-carbon corrosion-resistant composite cement, comprising the following raw materials in parts by weight: 20 to 25 parts of low-carbon high-silicon phase silicate cement clinker, 30 to 35 parts of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker, 20 to 25 parts of fly ash, 20 to 25 parts of building recycled micropowder, 0 to 5 parts of desulfurization gypsum, and 0.1 to 1 part of powder composite strengthener.

[0007] Preferably, the low-carbon, high-silicon phase silicate cement clinker comprises the following components in mass fractions: 70-80% tricalcium silicate, 5-10% dicalcium silicate, 5-10% tetracalcium aluminoferrite, and 10-20% tricalcium aluminate.

[0008] Preferably, the high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker comprises the following components in mass fractions: 25-30% calcium sulfosilicate, 40-45% calcium sulfoaluminate, 20-25% tetracalcium aluminoferrite, and 5-10% dicalcium silicate.

[0009] Preferably, the powder composite strengthener includes the following components by mass fraction: 50-65% sodium-based desulfurization ash, 30-45% aluminum sulfate, and 5-15% sodium tripolyphosphate;

[0010] The sodium-based desulfurization ash includes the following components by mass fraction: SiO2 0.24%, Al2O3 0.011%, Fe2O3 0.037%, CaO 0.332%, SO3 51.89%, K2O 0.006%, MgO 0.43%, Na2O 43.91%, and LOI 3.36%.

[0011] Preferably, the fly ash includes at least one of ultrafine fly ash, primary fly ash and secondary fly ash.

[0012] Preferably, the particle size of the building recycled fine powder is 50 to 90 μm;

[0013] The building recycled fine powder includes the following components by mass fraction: SiO2 25.26%, Al2O3 5.27%, Fe2O32.02%, CaO 30.81%, SO3 1.35%, K2O 0.14%, MgO 0.43%, Na2O 0.413%, LOI 33.947%;

[0014] The particle size of the fly ash is less than or equal to 4 μm.

[0015] Preferably, the desulfurization gypsum comprises the following components in mass fractions: SiO2 2.6%, Al2O3 0.7%, Fe2O3 0.82%, CaO 43.31%, SO3 40.73%, K2O 0.14%, MgO 0.91%, and LOI 3.36%.

[0016] In a second aspect, the present invention further provides a method for preparing the low-carbon corrosion-resistant composite cement, comprising the following steps:

[0017] crushing 30 to 35 parts by weight of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag;

[0018] crushing 20 to 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0019] The high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag is mixed with 0 to 3 parts by weight of desulfurized gypsum to obtain a high-silicon, iron-rich, low-carbon, corrosion-resistant cement binary material;

[0020] Mixing the low-carbon high-silicon phase Portland cement clinker residue with 0-2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0021] Adding the high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0022] Adding the low-carbon high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0023] The first cement mixture is classified by an air flow classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15 to 30 μm and 30 to 50 μm;

[0024] The second cement mixture is classified by an air classifier to obtain low-carbon high-silicon phase silicate cement with two particle size distributions of 4 to 15 μm and 15 to 30 μm;

[0025] Low-carbon corrosion-resistant composite cement is obtained by mixing two types of high-silicon iron-rich phase low-carbon corrosion-resistant cement with different particle size distributions, two types of low-carbon high-silicon phase silicate cement with different particle size distributions, 20 to 25 parts by weight of fly ash, 20 to 25 parts by weight of building recycled fine powder, and 0.1 to 1 part by weight of a powder composite strengthener.

[0026] Preferably, the grinding aid comprises diethanol monoisopropanolamine and triisopropanolamine, and the mass ratio of the diethanol monoisopropanolamine to the triisopropanolamine is (3-5):(2-4);

[0027] The high silicon iron-rich phase low carbon corrosion resistant cement binary material is added to a ball mill, and then a grinding aid is added, wherein the amount of the grinding aid added is 0.05-0.06% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material;

[0028] In the step of adding the low carbon high silicon phase silicate cement binary material into a ball mill and then adding a grinding aid, the amount of the grinding aid added is 0.05-0.06% of the mass of the low carbon high silicon phase silicate cement binary material.

[0029] Preferably, the mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30 to 50 μm is (4 to 5): (5 to 6);

[0030] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is (8 to 10):(2 to 4).

[0031] The low-carbon, corrosion-resistant composite cement and its preparation method of the present invention have the following beneficial effects compared with the prior art:

[0032] 1. The present invention is based on the "Fuller distribution" gradation design model and the hydration characteristics and grindability of different mineral compositions in each clinker. By adding high-performance grinding aids and designing the ball milling time to control the particle size distribution of the cementitious material, the silicon phase mineral composition in the low-carbon, high-silicon phase silicate cement clinker is distributed in a finer particle size range, while the iron-aluminum phase mineral composition in the high-silicon, iron-rich phase, low-carbon, corrosion-resistant cement clinker is distributed in a coarser particle size range. In addition, the hydration range of the silicon phase mineral composition in the low-carbon, high-silicon phase silicate cement clinker can be matched to the hydration range of the iron-aluminum phase mineral composition in the high-silicon, iron-rich phase, low-carbon, corrosion-resistant cement clinker to the greatest extent, promoting more aluminum ions to enter the gel, improving the polymerization degree and stability of the gel, and optimizing the mechanical properties and corrosion resistance of the gel. At the same time, the present invention uses high-performance grinding aids to greatly shorten the ball milling time of cement clinker and reduce carbon emissions during the cement clinker processing process.

[0033] 2. The present invention selects high silicon iron-rich phase low carbon corrosion resistant cement clinker and low carbon high silicon phase silicate cement clinker for compounding. Compatible with C3A and Achieve the effect of synergistic hydration, avoid concentrated distribution of calcium aluminoferrite, and achieve the effect of uniform enhancement. The present invention replaces the low-carbon, high-silicon phase silicate cement clinker calcined at high temperature with the high-silicon, iron-rich phase, low-carbon, corrosion-resistant cement clinker calcined at low temperature. At the same time, based on the "Fuller distribution" grading design model, ultrafine fly ash and building recycled micropowder are selected as ultrafine auxiliary cementitious materials and coarser auxiliary cementitious materials, and the particle size distribution of the composite cement is optimized to achieve the effect of close stacking. On the basis of ensuring the performance of all aspects of the cementitious material, the amount of cement clinker is reduced to the greatest extent, and the carbon emissions in the cement preparation process are reduced, thereby achieving the effect of energy conservation and emission reduction. The present invention forms a synergistic stimulation effect with the cement clinker hydration product by adding a composite strengthener, thereby improving the volcanic ash reaction of auxiliary cementitious materials such as fly ash and building recycled micropowder, optimizing the gel structure, and further ensuring the overall mechanical and corrosion resistance of the cementitious material. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of this application, the term "including" means "including but not limited to". Various embodiments of the present invention may be in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be understood as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0036] An embodiment of the present application provides a low-carbon, corrosion-resistant composite cement, comprising the following raw materials in parts by weight: 20 to 25 parts of low-carbon, high-silicon phase silicate cement clinker, 30 to 35 parts of high-silicon, iron-rich phase, low-carbon, corrosion-resistant cement clinker, 20 to 25 parts of fly ash, 20 to 25 parts of building recycled micropowder, 0 to 5 parts of desulfurized gypsum, and 0.1 to 1 part of a powder composite strengthener.

[0037] The composite cement of the present invention adopts the concept of "Fuller distribution" grading design to prepare low-carbon, corrosion-resistant, low-clinker consumption, high-performance composite cement. On the one hand, based on the hydration characteristics and grindability of iron-aluminum phase minerals and silicon phase minerals in the clinker, the particle size distribution of different types of cement clinker is regulated by adding high-performance grinding aids and designing the ball milling time, so that the silicon phase minerals and iron-aluminum phase minerals are more matched to form a gel with higher polymerization degree and more stable structure; on the other hand, ultrafine fly ash and building recycled micropowder are selected as ultrafine auxiliary cementitious materials and coarser auxiliary cementitious materials to achieve the effect of tight stacking. At the same time, the composite strengthener and the cement clinker hydration products form a synergistic excitation effect to improve the hydration degree of auxiliary cementitious materials such as ultrafine fly ash and building recycled micropowder, optimize the gel structure, and thus improve the overall mechanical and corrosion resistance.

[0038] In some embodiments, the low-carbon, high-silicon phase silicate cement clinker includes the following mineral components in mass fractions: tricalcium silicate (C3S) 70-80%, dicalcium silicate (C2S) 5-10%, tetracalcium aluminoferrite (C4AF) 5-10%, and tricalcium aluminate (C3A) 10-20%.

[0039] In some embodiments, the high silicon iron-rich phase low carbon corrosion resistant cement clinker includes the following mineral components by mass fraction: calcium sulfosilicate ( Ca5(SiO4)2SO4)25~30%, calcium sulfoaluminate 40-45%, tetracalcium aluminoferrite (C4AF) 20-25%, dicalcium silicate (C2S) 5-10%.

[0040] In some embodiments, the powder composite enhancer includes the following components by mass fraction: 50-65% sodium-based desulfurization ash, 30-45% aluminum sulfate, and 5-15% sodium tripolyphosphate. The aluminum sulfate and sodium tripolyphosphate used are commercially available materials. The sodium-based desulfurization ash includes the components by mass fraction shown in Table 1.

[0041] Table 1 - Chemical composition of sodium-based desulfurization ash

[0042]

[0043] In some embodiments, the fly ash includes at least one of ultrafine fly ash, primary fly ash, and secondary fly ash.

[0044] In some embodiments, the fly ash has a particle size of 4 μm or less.

[0045] In some embodiments, the particle size of the recycled construction powder is 50 to 90 μm. The recycled construction powder is derived from waste C50 concrete and is primarily composed of cement stone fine powder and limestone powder. The particle size range is controlled to be 50 to 90 μm. Its chemical composition is shown in Table 2:

[0046] Table 2 - Chemical composition of building recycled powder

[0047]

[0048] In some embodiments, desulfurization gypsum is a by-product of the dry desulfurization process in steel mills, and is mainly composed of calcium sulfite hemihydrate, calcium carbonate, fly ash, and calcium hydroxide. Its main chemical components are shown in Table 3:

[0049] Table 3 - Chemical composition of desulfurized gypsum

[0050]

[0051]

[0052] The present invention adopts phase and Composite high silicon iron-rich low carbon corrosion resistant cement clinker (25% to 30% Minerals, 40% to 45% Minerals, 20% to 25% C4AF minerals, 5% to 10% C2S) are compounded with high silicon iron-rich low carbon corrosion resistant cement clinker (70% to 80% C3S minerals, 5% to 10% C2S minerals, 5% to 10% C4AF minerals, 10% to 20% C3A content). With aluminum phase (C3A and )'s synergistic hydration reaction optimizes the distribution effect of calcium aluminoferrite, thereby enhancing the structure of the composite cementitious material and optimizing the strength and toughness of the cementitious slurry; in the pretreatment process of ordinary silicate and high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker, the present invention makes the main distribution intervals of different cement clinkers concentrate in the corresponding intervals of the grading model according to the raw material characteristics to achieve a tight stacking effect, and at the same time makes the hydration intervals of silicon phase minerals and aluminum phase minerals match, promotes more aluminum ions to enter the gel, optimizes the gel structure, reduces the amount of clinker used, and improves the overall mechanical properties and durability of the material. The present invention also improves the hydration degree of auxiliary cementitious materials and optimizes the pore structure through the synergistic excitation effect between the composite strengthener and the cement hydration product, further matches the hydration intervals of silicon phase minerals and aluminum phase minerals, reduces the amount of cement clinker, and increases the amount of auxiliary cementitious materials such as building recycled micropowder, further achieving the effect of carbon reduction and emission reduction.

[0053] The present invention adopts phase and Composite low carbon corrosion resistant composite cement (25%-30% Minerals, 40%-45% Minerals, 20%-25% C4AF minerals, 5%-10% C2S), using With C3A and The synergistic hydration effect can achieve the effect of uniform distribution of ettringite, optimize the gel structure, reduce the amount of clinker, and improve the overall mechanical properties and durability of the material; at the same time, The mineral phase hydration forms expansive hydration products such as calcium aluminoferrite to compensate for the shrinkage of C80 concrete, which can improve the crack resistance of concrete; in addition, the high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker has a low calcination temperature, which is about 200°C lower than the calcination temperature of traditional silicate cement clinker (1400°C), which significantly reduces coal consumption and further reduces carbon emissions, realizing the low-carbon preparation of corrosion-resistant, low-clinker dosage, high-performance composite cement.

[0054] Specific phase and The preparation method of the composite high silicon iron-rich phase low carbon corrosion resistant cement clinker is as follows:

[0055] Mix limestone (60%-70%), phosphogypsum (10%-15%), bauxite (20%-25%), fly ash (5%-10%), and add 0.5% fluorine to ensure and The mixture is mixed and pressed into a cake, and then heated to 1200℃ at a rate of 5℃ / min and calcined; after keeping the mixture at this temperature for 40-45min, the mixture is quickly taken out and cooled to room temperature by blasting to prepare calcium sulfosilicate-calcium sulfoaluminate clinker. The main mineral composition of the clinker is 25%-30% Minerals, 40%-45% minerals, 20%-25% C4AF minerals, 5%-10% C2S.

[0056] The specific preparation method of low carbon high silicon phase silicate cement clinker is:

[0057] Limestone (70%-80%), clay (5%-10%), coal gangue (5%-10%), fly ash (5%-10%) and iron powder (1%-5%) are uniformly mixed, and CuO and CaF2 accounting for 1% of the raw material are used as calcination accelerators. The mixture is heated to 1450°C at a rate of 5°C / min and calcined. After being kept at 1450°C for 30 minutes, the mixture is quickly taken out and blast-cooled to room temperature to produce high-C3S Portland cement clinker with a main mineral composition of 70%-80% C3S minerals, 5%-10% C2S minerals, 5%-10% C4AF minerals, and 10%-20% C3A content ≥75%.

[0058] The low-carbon, corrosion-resistant, low-clinker dosage, high-performance composite cement prepared by the present invention has the characteristics of early strength, corrosion resistance and shrinkage compensation, which effectively solves the problems of low early strength and poor corrosion resistance of current low-carbon composite cement materials. The high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker used can improve the early strength and corrosion resistance of cementitious materials, reduce the steaming time of large-volume prefabricated components, ensure long-term performance, and further reduce overall carbon emissions; the present application incorporates a powder composite strengthener (50% to 65% sodium-based desulfurization ash, 30% to 45% aluminum sulfate and 5% to 15% sodium tripolyphosphate), and improves the hydration degree of fly ash and building recycled micropowder through the synergistic effect between sodium-based desulfurization ash and cement clinker hydration products such as calcium hydroxide, thereby optimizing the cementitious materials. The pore structure and mechanical properties of the material are improved, thereby further reducing the amount of cement clinker. At the same time, aluminum sulfate and sodium tripolyphosphate are used to regulate the clinker setting time and the morphology of ettringite, optimize the gel microstructure, and achieve the effect of controllable setting time, which has an important guiding role in the research and development and preparation of cementitious materials. The low-carbon, corrosion-resistant, low-clinker-dosage high-performance composite cement prepared by the present invention has a 1d compressive strength of ≥32.6MPa, a 28d compressive strength of ≥58.4Mpa, and a 28d chloride ion diffusion coefficient of 0.54×10 -12 m 2 / s, 180d seawater corrosion resistance coefficient K 180 ≥1.10, and at the same time has stronger resistance to deformation and has important practical application value.

[0059] The low-carbon, corrosion-resistant composite cement produced by this invention uses high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker, which can reduce the calcination temperature to 1200°C, while also reducing grinding energy consumption and lowering CO2 emissions during the production process by approximately 20%. Furthermore, the invention replaces cement clinker with large amounts of admixtures such as fly ash microbeads, recycled construction powder, and desulfurized gypsum, further significantly reducing carbon emissions and achieving energy conservation and emission reduction.

[0060] Based on the same inventive concept, the present invention also provides a method for preparing low-carbon corrosion-resistant composite cement, comprising the following steps:

[0061] The present invention also provides a method for preparing the low-carbon corrosion-resistant composite cement, comprising the following steps:

[0062] S1. Crushing 30 to 35 parts by weight of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag;

[0063] S2. crushing 20 to 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0064] S3, mixing high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag with 0-3 parts by weight of desulfurized gypsum to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material;

[0065] S4, mixing low-carbon high-silicon phase Portland cement clinker slag with 0-2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0066] S5, adding a high silicon iron-rich phase low carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0067] S6. Adding a low-carbon, high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0068] S7, classifying the first cement mixture through an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15 to 30 μm and 30 to 50 μm;

[0069] S8, classifying the second cement mixture through an air classifier to obtain low-carbon, high-silicon phase Portland cement with two particle size distributions of 4 to 15 μm and 15 to 30 μm;

[0070] S9. Mix two types of high-silicon iron-rich phase low-carbon corrosion-resistant cement with different particle size distributions, two types of low-carbon high-silicon phase silicate cement with different particle size distributions, 20 to 25 parts by weight of fly ash, 20 to 25 parts by weight of building recycled fine powder, and 0.1 to 1 part by weight of a powder composite strengthener to obtain low-carbon corrosion-resistant composite cement.

[0071] In some embodiments, the grinding aid includes diethanol monoisopropanolamine and triisopropanolamine, and the mass ratio of diethanol monoisopropanolamine to triisopropanolamine is (3-5):(2-4).

[0072] In some embodiments, in the step of adding high silicon iron-rich phase low carbon corrosion resistant cement binary material to a ball mill and then adding a grinding aid, the amount of the grinding aid added is 0.05-0.06% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material.

[0073] In some embodiments, in the step of adding the low carbon high silicon phase silicate cement binary material to the ball mill and then adding the grinding aid, the amount of the grinding aid added is 0.05-0.06% of the mass of the low carbon high silicon phase silicate cement binary material.

[0074] In some embodiments, the mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30 to 50 μm is (4 to 5): (5 to 6).

[0075] In some embodiments, the mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is (8 to 10):(2 to 4).

[0076] In some embodiments, the air classifier speed is controlled to be 100-200 rpm, and the first cement mixture is classified by the air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15-30 μm and 30-50 μm;

[0077] In some embodiments, the air classifier speed is controlled to be 500-1000 rpm, and the second cement mixture is classified by the air classifier to obtain low-carbon high-silicon phase Portland cement with two particle size distributions of 4-15 μm and 15-30 μm.

[0078] The present invention adopts phase and Composite high silicon iron-rich low carbon corrosion resistant cement clinker (25% to 30% Minerals, 40% to 45% Minerals, 20% to 25% C4AF minerals, 5% to 10% C2S) are compounded with low carbon high silicon phase silicate cement clinker. Compatible with C3A and The synergistic hydration effect of calcium aluminate can achieve the effect of uniform distribution of calcium sulfide, optimize the gel structure, reduce the amount of clinker used, and improve the overall mechanical properties and durability of the material. Based on the hydration characteristics and grindability of the iron-aluminum phase minerals and silicon phase minerals in the clinker, the particle size distribution range of the cementitious material is regulated by adding high-performance grinding aids and designing the ball milling time. In combination with the air flow classifier, the main particle size range of the high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker is controlled to 15-30μm and 30-50μm, and the main particle size range of the low-carbon high-silicon phase silicate cement clinker is controlled to 4-15μm and 15-30μm, so that the hydration range of silicon phase minerals and aluminum phase minerals is matched, promoting more aluminum ions to enter the gel, and improving the polymerization degree and stability of the gel. In addition, fly ash and construction recycled fine powder are selected as ultrafine auxiliary cementitious materials and coarser auxiliary cementitious materials to achieve a dense stacking effect. During the preparation process, graded cement clinker, fly ash, building recycled fine powder, gypsum and powder composite strengthener are added to a dry mixer at the same time and stirred for 10 minutes to obtain the carbon corrosion-resistant low clinker dosage high-performance composite cement.

[0079] The following further illustrates the low-carbon, corrosion-resistant composite cement and its preparation method of the present invention with reference to specific examples. This section further illustrates the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0080] In the following examples and comparative examples, fly ash was produced by a Tianjin chemical reagent Co., Ltd. and had an average particle size of 2 μm; building recycled micropowder was provided by Suzhou Lvpu New Material Technology Co., Ltd. and had an average particle size of 70 μm, including the following components by mass fraction: SiO2 25.26%, Al2O3 5.27%, Fe2O3 2.02%, CaO 30.81%, SO3 1.35%, K2O0.14%, MgO 0.43%, Na2O 0.413%, LOI 33.947%; desulfurization gypsum was produced by Jiangsu Yonggang Group and included the following components by mass fraction: SiO2 2.6%, Al2O3 0.7%, Fe2O30.82%, CaO 43.31%, SO3 40.73%, K2O0.14%, MgO 0.91%, LOI 3.36%; aluminum sulfate and sodium tripolyphosphate are commercially available materials provided by Henan Boyue Chemical Products Co., Ltd.; diethanol monoisopropanolamine and triisopropanolamine (content ≥ 99.0%) are provided by Shanghai Xiangu Chemical Co., Ltd.

[0081] The low carbon and high silicon phase silicate cement clinker includes the following mineral components by mass fraction: tricalcium silicate (C3S) 75%, dicalcium silicate (C2S) 8%, tetracalcium aluminoferrite (C4AF) 7%, tricalcium aluminate (C3A) 10%;

[0082] High silicon iron-rich phase low carbon corrosion resistant cement clinker includes the following mineral components by mass fraction: calcium sulfosilicate ( Ca5(SiO4)2SO4)25%, calcium sulfoaluminate 40%, tetracalcium aluminoferrite (C4AF) 25%, dicalcium silicate (C2S) 10%;

[0083] The powder composite strengthener includes the following components by mass fraction: 50% of sodium-based desulfurization ash, 40% of aluminum sulfate, and 10% of sodium tripolyphosphate; the sodium-based desulfurization ash includes the following components by mass fraction: 0.24% of SiO2, 0.011% of Al2O3, 0.037% of Fe2O3, 0.332% of CaO, 51.89% of SO3, 0.006% of K2O, 0.43% of MgO, 43.91% of Na2O, and 3.36% of LOI;

[0084] The grinding aids include diethanol monoisopropanolamine and triisopropanolamine, and the mass ratio of diethanol monoisopropanolamine to triisopropanolamine is 3:2.

[0085] Example 1

[0086] The present invention provides a low-carbon corrosion-resistant composite cement, comprising the following raw materials in parts by weight: 25 parts of low-carbon high-silicon phase silicate cement clinker, 32 parts of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker, 25 parts of fly ash, 20 parts of building recycled fine powder, 4 parts of desulfurized gypsum, and 0.5 parts of a powder composite strengthener;

[0087] The preparation method of the low-carbon corrosion-resistant composite cement comprises the following steps:

[0088] S1. Crushing 32 parts by weight of high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag;

[0089] S2. crushing 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0090] S3, mixing high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag with 2 parts by weight of desulfurized gypsum to obtain a high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material;

[0091] S4, mixing low-carbon high-silicon phase Portland cement clinker residue with 2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0092] S5, adding a high silicon iron-rich phase low carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0093] S6. Adding a low-carbon, high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0094] S7, classifying the first cement mixture through an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15 to 30 μm and 30 to 50 μm;

[0095] S8, classifying the second cement mixture through an air classifier to obtain low-carbon, high-silicon phase Portland cement with two particle size distributions of 4 to 15 μm and 15 to 30 μm;

[0096] S9. Mix two high-silicon iron-rich phase low-carbon corrosion-resistant cements with different particle size distributions, two low-carbon high-silicon phase Portland cements with different particle size distributions, 25 parts by weight of fly ash, 20 parts by weight of building recycled fine powder, and 0.5 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a low-carbon corrosion-resistant composite cement;

[0097] The step of adding the high silicon iron-rich phase low carbon corrosion resistant cement binary material to the ball mill and then adding the grinding aid is performed in an amount of 0.05% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material.

[0098] Adding low carbon high silicon phase silicate cement binary material into a ball mill, and then adding a grinding aid, wherein the amount of the grinding aid added is 0.05% of the mass of the low carbon high silicon phase silicate cement binary material;

[0099] The mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30 to 50 μm is 4:5;

[0100] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is 8:2.

[0101] Example 2

[0102] An embodiment of the present application provides a low-carbon, corrosion-resistant composite cement, comprising the following raw materials in parts by weight: 25 parts of low-carbon, high-silicon phase silicate cement clinker, 32 parts of high-silicon, iron-rich phase low-carbon, corrosion-resistant cement clinker, 25 parts of fly ash, 20 parts of building recycled micropowder, 4 parts of desulfurized gypsum, and 0.1 parts of powder composite strengthener.

[0103] The preparation method of the low-carbon corrosion-resistant composite cement comprises the following steps:

[0104] S1. Crushing 32 parts by weight of high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag;

[0105] S2. crushing 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0106] S3, mixing high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag with 2 parts by weight of desulfurized gypsum to obtain a high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material;

[0107] S4, mixing low-carbon high-silicon phase Portland cement clinker residue with 2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0108] S5, adding a high silicon iron-rich phase low carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0109] S6. Adding a low-carbon, high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0110] S7, classifying the first cement mixture through an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15 to 30 μm and 30 to 50 μm;

[0111] S8, classifying the second cement mixture through an air classifier to obtain low-carbon, high-silicon phase Portland cement with two particle size distributions of 4 to 15 μm and 15 to 30 μm;

[0112] S9. Mix two high-silicon iron-rich phase low-carbon corrosion-resistant cements with two particle size distributions, two low-carbon high-silicon phase Portland cements with two particle size distributions, 25 parts by weight of fly ash, 20 parts by weight of building recycled fine powder, and 0.1 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a low-carbon corrosion-resistant composite cement;

[0113] The step of adding the high silicon iron-rich phase low carbon corrosion resistant cement binary material to the ball mill and then adding the grinding aid is performed in an amount of 0.05% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material.

[0114] Adding low carbon high silicon phase silicate cement binary material into a ball mill, and then adding a grinding aid, wherein the amount of the grinding aid added is 0.05% of the mass of the low carbon high silicon phase silicate cement binary material;

[0115] The mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30 to 50 μm is 4:5;

[0116] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is 8:2.

[0117] Example 3

[0118] The present invention provides a low-carbon, corrosion-resistant composite cement comprising the following raw materials in parts by weight: 25 parts of low-carbon, high-silicon phase silicate cement clinker, 32 parts of high-silicon, iron-rich phase low-carbon, corrosion-resistant cement clinker, 25 parts of fly ash, 20 parts of building recycled micropowder, 0 parts of desulfurized gypsum, and 0.5 parts of a powder composite strengthener.

[0119] The preparation method of the low-carbon corrosion-resistant composite cement comprises the following steps:

[0120] S1. Crushing 32 parts by weight of high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag;

[0121] S2. crushing 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0122] S3, mixing high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag with 0 parts by weight of desulfurized gypsum to obtain a high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material;

[0123] S4, mixing low-carbon high-silicon phase Portland cement clinker residue with 0 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0124] S5, adding a high silicon iron-rich phase low carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0125] S6. Adding a low-carbon, high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0126] S7, classifying the first cement mixture through an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15 to 30 μm and 30 to 50 μm;

[0127] S8, classifying the second cement mixture through an air classifier to obtain low-carbon, high-silicon phase Portland cement with two particle size distributions of 4 to 15 μm and 15 to 30 μm;

[0128] S9. Mix two high-silicon iron-rich phase low-carbon corrosion-resistant cements with different particle size distributions, two low-carbon high-silicon phase Portland cements with different particle size distributions, 25 parts by weight of fly ash, 20 parts by weight of building recycled fine powder, and 0.5 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a low-carbon corrosion-resistant composite cement;

[0129] The step of adding the high silicon iron-rich phase low carbon corrosion resistant cement binary material to the ball mill and then adding the grinding aid is performed in an amount of 0.05% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material.

[0130] Adding low carbon high silicon phase silicate cement binary material into a ball mill, and then adding a grinding aid, wherein the amount of the grinding aid added is 0.05% of the mass of the low carbon high silicon phase silicate cement binary material;

[0131] The mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30 to 50 μm is 4:5;

[0132] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is 8:2.

[0133] Example 4

[0134] The present invention provides a low-carbon corrosion-resistant composite cement, comprising the following raw materials in parts by weight: 25 parts of low-carbon high-silicon phase silicate cement clinker, 32 parts of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker, 20 parts of fly ash, 25 parts of building recycled micropowder, 4 parts of desulfurized gypsum, and 0.5 parts of a powder composite strengthener;

[0135] The preparation method of the low-carbon corrosion-resistant composite cement comprises the following steps:

[0136] S1. Crushing 32 parts by weight of high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag;

[0137] S2. crushing 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0138] S3, mixing high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag with 2 parts by weight of desulfurized gypsum to obtain a high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material;

[0139] S4, mixing low-carbon high-silicon phase Portland cement clinker residue with 2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0140] S5, adding a high silicon iron-rich phase low carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0141] S6. Adding a low-carbon, high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0142] S7, classifying the first cement mixture through an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15 to 30 μm and 30 to 50 μm;

[0143] S8, classifying the second cement mixture through an air classifier to obtain low-carbon, high-silicon phase Portland cement with two particle size distributions of 4 to 15 μm and 15 to 30 μm;

[0144] S9. Mix two high-silicon iron-rich phase low-carbon corrosion-resistant cements with different particle size distributions, two low-carbon high-silicon phase Portland cements with different particle size distributions, 20 parts by weight of fly ash, 25 parts by weight of building recycled fine powder, and 0.5 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a low-carbon corrosion-resistant composite cement;

[0145] The step of adding the high silicon iron-rich phase low carbon corrosion resistant cement binary material to the ball mill and then adding the grinding aid is performed in an amount of 0.05% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material.

[0146] Adding low carbon high silicon phase silicate cement binary material into a ball mill, and then adding a grinding aid, wherein the amount of the grinding aid added is 0.05% of the mass of the low carbon high silicon phase silicate cement binary material;

[0147] The mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30 to 50 μm is 4:5;

[0148] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is 8:2.

[0149] Comparative Example 1

[0150] This comparative example provides a composite cement comprising the following raw materials in parts by weight: 57 parts of low-carbon high-silicon phase Portland cement clinker, 24 parts of fly ash, 19 parts of building recycled micro powder, 4 parts of desulfurized gypsum, and 0.5 parts of a powder composite strengthener;

[0151] The preparation method of the composite cement comprises the following steps:

[0152] S1. Crushing 57 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0153] S2, mixing low-carbon high-silicon phase Portland cement clinker residue with 4 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0154] S3, adding a low-carbon high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.03 mm;

[0155] S4, classifying the first cement mixture through an air classifier to obtain low-carbon high-silicon phase Portland cement with two particle size distributions of 4-15 μm and 15-30 μm;

[0156] S5. Mix two low-carbon, high-silicon phase Portland cements with different particle size distributions, 24 parts by weight of fly ash, 19 parts by weight of building recycled fine powder, and 0.5 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a composite cement;

[0157] The low carbon high silicon phase silicate cement binary material is added to the ball mill, and then the grinding aid is added in an amount of 0.05% of the mass of the low carbon high silicon phase silicate cement binary material.

[0158] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is 8:2.

[0159] Comparative Example 2

[0160] This comparative example provides a composite cement comprising the following raw materials in parts by weight: 57 parts of low-carbon high-silicon phase Portland cement clinker, 43 parts of fly ash, 4 parts of desulfurized gypsum, and 0.5 parts of a powder composite strengthener.

[0161] The preparation method of the composite cement comprises the following steps:

[0162] S1. Crushing 57 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0163] S2, mixing low-carbon high-silicon phase Portland cement clinker residue with 4 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0164] S3, adding a low-carbon high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.03 mm;

[0165] S4, classifying the first cement mixture through an air classifier to obtain low-carbon high-silicon phase Portland cement with two particle size distributions of 4-15 μm and 15-30 μm;

[0166] S5. Mix two low-carbon, high-silicon phase Portland cements with different particle size distributions, 43 parts by weight of fly ash, 19 parts by weight of recycled building powder, and 0.5 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a composite cement;

[0167] The low carbon high silicon phase silicate cement binary material is added to the ball mill, and then the grinding aid is added in an amount of 0.05% of the mass of the low carbon high silicon phase silicate cement binary material.

[0168] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 4 to 15 μm to low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm is 8:2.

[0169] Comparative Example 3

[0170] This comparative example provides a low-carbon corrosion-resistant composite cement, comprising the following raw materials in parts by weight: 25 parts of low-carbon high-silicon phase silicate cement clinker, 32 parts of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker, 25 parts of fly ash, 20 parts of building recycled micropowder, 4 parts of desulfurized gypsum, and 0.5 parts of a powder composite strengthener;

[0171] The preparation method of the low-carbon corrosion-resistant composite cement comprises the following steps:

[0172] S1. Crushing 25 parts by weight of high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag;

[0173] S2. crushing 32 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag;

[0174] S3, mixing high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag with 2 parts by weight of desulfurized gypsum to obtain a high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material;

[0175] S4, mixing low-carbon high-silicon phase Portland cement clinker residue with 2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material;

[0176] S5, adding a high silicon iron-rich phase low carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm;

[0177] S6. Adding a low-carbon, high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm;

[0178] S7, classifying the first cement mixture through an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 4-15 μm and 15-30 μm;

[0179] S8, classifying the second cement mixture through an air classifier to obtain low-carbon high-silicon phase Portland cement with a particle size of 15-30 μm and 30-50 μm;

[0180] S9. Mix two high-silicon iron-rich phase low-carbon corrosion-resistant cements with different particle size distributions, two low-carbon high-silicon phase Portland cements with different particle size distributions, 25 parts by weight of fly ash, 20 parts by weight of building recycled fine powder, and 0.5 parts by weight of a powder composite strengthener, and stir for 10 minutes to obtain a low-carbon corrosion-resistant composite cement;

[0181] The step of adding the high silicon iron-rich phase low carbon corrosion resistant cement binary material to the ball mill and then adding the grinding aid is performed in an amount of 0.05% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material.

[0182] Adding low carbon high silicon phase silicate cement binary material into a ball mill, and then adding a grinding aid, wherein the amount of the grinding aid added is 0.05% of the mass of the low carbon high silicon phase silicate cement binary material;

[0183] The mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 4 to 15 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15 to 30 μm is 4:5;

[0184] The mass ratio of low carbon high silicon phase silicate cement with a particle size of 15 to 30 μm to low carbon high silicon phase silicate cement with a particle size of 30 to 50 μm is 8:2.

[0185] The low-carbon corrosion-resistant composite cements prepared in Examples 1 to 4 and the composite cements prepared in Comparative Examples 1 to 3 were subjected to compressive strength, chloride ion diffusion tests, and seawater erosion resistance tests. The specific operations are as follows:

[0186] Mechanical properties test method: For specific test methods, refer to "Test method for strength of cement mortar (ISO method)" (GB / T17671-2021). The test results are shown in Table 4.

[0187] Chloride ion diffusion test: For the specific test method, refer to "Test of Chloride Ion Diffusion Coefficient of Cement" (JC / T1086-2008). The test results are shown in Table 4.

[0188] Seawater erosion resistance test: For specific experimental methods, refer to the "Test Method for Cement Resistance to Seawater Erosion" (GB / T38140-2019). The test results are shown in Table 4.

[0189] Linear expansion test: The specific experimental method refers to the "Test method for drying shrinkage and cracking performance of cement mortar and concrete" (GB / T 29417-2012). The test results are shown in Table 4.

[0190] The experimental results are shown in the following table:

[0191] Table 4 - Composite cement test properties

[0192]

[0193] As can be seen from Table 2, the low-carbon corrosion-resistant composite cement prepared in the embodiment of the present invention has high 3d and 28d compressive strengths and good mechanical properties; this indicates that in the raw material ratio, while comprehensively considering carbon emissions and corrosion resistance, fly ash and building recycled fine powder are added, and the composite reinforcer is added to assist in stimulation, so that the composite cement obtained has good comprehensive performance. By comparing Comparative Example 3 with Example 1, it can be seen that when the main particle size ranges of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker and low-carbon high-silicon phase silicate cement clinker are controlled in the ranges of 15-30μm and 30-50μm and 4-15μm and 15-30μm respectively, the hydration range of iron-aluminum phases such as C4AF in high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker can be effectively matched with the hydration range of silicon phase minerals such as C3S in low-carbon high-silicon phase silicate cement clinker, promoting more Al 3+ Enter the CSH gel, thereby optimizing the gel structure, reducing the amount of cement clinker, ensuring cement performance, reducing cement production costs, and improving its corrosion resistance. Compared with the sample without the addition of ferroaluminate cement (Comparative Example 1), the sample with the coordinated gradation design of ferroaluminate cement and ordinary Portland cement (Example 1) has better comprehensive performance of the prepared cementitious material. Compared with the sample without the addition of ordinary Portland cement (Comparative Example 2), the sample with the coordinated gradation design of ferroaluminate cement and ordinary Portland cement (Example 1) has better late mechanical properties and corrosion resistance. Compared with the sample with only a small amount of powder composite strengthener added (Example 2), the sample with an appropriate amount of powder reinforcer added (Example 1), not only the early strength, but also the setting time is controlled, while avoiding the phenomenon of calcium aluminate aggregation, the pore structure is optimized, and the corrosion resistance is stronger.

[0194] It can be understood that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0195] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A low-carbon corrosion-resistant composite cement, characterized in that: The raw materials include the following parts by weight: 20-25 parts of low-carbon high-silicon phase silicate cement clinker, 30-35 parts of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker, 20-25 parts of fly ash, 20-25 parts of building recycled micro powder, 0-5 parts of desulfurized gypsum, and 0.1-1 parts of powder composite strengthener; The low-carbon high-silicon phase Portland cement clinker comprises the following components by mass fraction: 70-80% tricalcium silicate, 5-10% dicalcium silicate, 5-10% tetracalcium aluminoferrite, and 10-20% tricalcium aluminate; The high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker comprises the following components by mass fraction: 25-30% calcium sulfosilicate, 40-45% calcium sulfoaluminate, 20-25% tetracalcium aluminoferrite, and 5-10% dicalcium silicate.

2. The low-carbon corrosion-resistant composite cement according to claim 1, characterized in that: The powder composite enhancer comprises the following components by mass fraction: 50-65% sodium-based desulfurization ash, 30-45% aluminum sulfate, and 5-15% sodium tripolyphosphate; The sodium-based desulfurization ash includes the following components by mass fraction: SiO2 0.24%, Al2O3 0.011%, Fe2O3 0.037%, CaO 0.332%, SO3 51.89%, K2O 0.006%, MgO 0.43%, Na2O 43.91%, and LOI 3.36%.

3. The low-carbon corrosion-resistant composite cement according to claim 1, characterized in that: The fly ash includes at least one of ultrafine fly ash, primary fly ash and secondary fly ash.

4. The low-carbon corrosion-resistant composite cement according to claim 1, characterized in that: The particle size of the building recycled micropowder is 50-90 μm; The building recycled fine powder includes the following components by mass fraction: SiO2 25.26%, Al2O3 5.27%, Fe2O3 2.02%, CaO 30.81%, SO3 1.35%, K2O 0.14%, MgO 0.43%, Na2O 0.413%, LOI 33.947%; The particle size of the fly ash is less than or equal to 4 μm.

5. The low-carbon corrosion-resistant composite cement according to claim 1, characterized in that: The desulfurization gypsum includes the following components in mass fractions: SiO2 2.6%, Al2O3 0.7%, Fe2O3 0.82%, CaO 43.31%, SO3 40.73%, K2O 0.14%, MgO 0.91%, and LOI 3.36%.

6. A method for preparing the low-carbon, corrosion-resistant composite cement according to any one of claims 1 to 5, characterized in that: The following steps are involved: crushing 30 to 35 parts by weight of high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker to a particle size of less than 15 mm to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement clinker slag; crushing 20 to 25 parts by weight of low-carbon, high-silicon phase Portland cement clinker to a particle size of less than 15 mm to obtain low-carbon, high-silicon phase Portland cement clinker slag; The high-silicon, iron-rich, low-carbon, corrosion-resistant cement clinker slag is mixed with 0-3 parts by weight of desulfurized gypsum to obtain a high-silicon, iron-rich, low-carbon, corrosion-resistant cement binary material; Mixing the low-carbon high-silicon phase Portland cement clinker residue with 0-2 parts by weight of desulfurized gypsum to obtain a low-carbon high-silicon phase Portland cement binary material; Adding the high-silicon iron-rich phase low-carbon corrosion-resistant cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a first cement mixture with a particle size of less than 0.05 mm; Adding the low-carbon high-silicon phase silicate cement binary material into a ball mill, adding a grinding aid, and ball milling to obtain a second cement mixture with a particle size of less than 0.03 mm; The first cement mixture is classified by an air classifier to obtain high-silicon iron-rich phase low-carbon corrosion-resistant cement with two particle size distributions of 15-30 μm and 30-50 μm; The second cement mixture is classified by an air classifier to obtain low-carbon high-silicon phase Portland cement with two particle size distributions of 4-15 μm and 15-30 μm; Low-carbon corrosion-resistant composite cement is obtained by mixing two types of high-silicon iron-rich phase low-carbon corrosion-resistant cement with two types of particle size distribution, two types of low-carbon high-silicon phase silicate cement with two types of particle size distribution, 20-25 parts by weight of fly ash, 20-25 parts by weight of building recycled fine powder, and 0.1-1 part by weight of powder composite strengthener.

7. The method for preparing low-carbon corrosion-resistant composite cement according to claim 6, characterized in that: The grinding aid comprises diethanol monoisopropanolamine and triisopropanolamine, and the mass ratio of the diethanol monoisopropanolamine and triisopropanolamine is (3-5): (2-4); In the step of adding the high silicon iron-rich phase low carbon corrosion resistant cement binary material into a ball mill and then adding a grinding aid, the amount of the grinding aid added is 0.05-0.06% of the mass of the high silicon iron-rich phase low carbon corrosion resistant cement binary material; In the step of adding the low carbon high silicon phase silicate cement binary material into a ball mill and then adding a grinding aid, the amount of the grinding aid added is 0.05-0.06% of the mass of the low carbon high silicon phase silicate cement binary material.

8. The method for preparing low-carbon corrosion-resistant composite cement according to claim 6, wherein: The mass ratio of high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 15-30 μm to high silicon iron-rich phase low carbon corrosion resistant cement with a particle size of 30-50 μm is (4-5):(5-6); The mass ratio of low carbon high silicon phase silicate cement with particle size of 4~15μm to low carbon high silicon phase silicate cement with particle size of 15~30μm is (8~10):(2~4).

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