Carbonate rock powder-based mineral admixture and method for preparing the same

Abstract

The application discloses a carbonate rock powder-based mineral admixture and a preparation method thereof, and relates to the technical field of mineral compositions; the carbonate rock powder-based mineral admixture comprises the following components in proportion by weight: 50-60 parts of carbonate rock powder, 30-40 parts of biomass ash and 10 parts of red mud; the three kinds of bulk solid wastes, i.e., the carbonate rock powder, the biomass ash and the red mud, are compounded, the inherent defects of single carbonate rock powder in the application in concrete are successfully solved, and high-quality and bulk-quantity utilization of multi-source solid wastes are realized; based on the physical and chemical synergistic effect among the components, tight particle packing is realized, when the carbonate rock powder-based mineral admixture is applied in concrete, not only the workability of fresh concrete is ensured, but also the hardened concrete structure is extremely dense, and the mechanical strength, the impermeability, the corrosion resistance and other durability of the hardened concrete structure are improved.

Description

Technical Field

[0001] This invention relates to the field of mineral composition technology, specifically to a carbonate rock powder-based mineral admixture and its preparation method. Background Technology

[0002] To address the shortage of natural aggregates, more concrete projects are using artificial aggregates made from crushed rocks. This process inevitably generates a large amount of stone chips and powder, which not only pollutes the air and land but also occupies land and wastes resources. Reprocessing these materials into concrete mineral admixtures is an important way to solve the dual dilemma of low utilization rate of solid waste resources and shortage of traditional mineral admixture resources.

[0003] According to national statistics on the lithology of parent rocks for artificial sand and gravel, limestone, dolomite, and marble rank second in terms of mining volume. Using waste stone powder generated during mining as a mineral admixture for concrete has advantages such as abundant resources, easy access, and low cost. Carbonate rock powder has been studied and applied in cement-based materials to some extent. Limestone powder has been used in cement-based materials for over thirty years, and its application has developed rapidly worldwide in the last decade, with many countries, including my country, issuing corresponding standards and specifications. In recent years, the research and application of dolomite powder and marble powder in cement-based materials have also received more attention. Carbonate rock powder, as a mineral admixture for cement concrete, has both a theoretical basis and application prospects.

[0004] Existing research indicates that carbonate rock powder plays a role in cement concrete through filling, nucleation, chemical action, and dilution. At certain dosages, it can improve the fluidity of cement concrete, reduce segregation and bleeding, and its filling and compacting effects, nucleation promoting cement hydration, and chemical action forming aluminocarbonates all contribute to improving pore structure, enhancing early strength and durability, and reducing drying shrinkage. However, the main mineral component of carbonate rock powder, CaCO3 / CaCO3·MgCO3, itself lacks cementitious and pozzolanic activity and has low hydration activity. When it replaces cement in large quantities, dilution becomes dominant, leading to a decrease in the formation of hydration products, coarsening of the pore structure, and a significant reduction in strength and durability. Summary of the Invention

[0005] The present invention aims to solve the problems that occur when carbonate rock powder is directly added to concrete in large quantities to replace cement, resulting in a decrease in the amount of hydration products generated, coarsening of pore structure, and a significant decrease in strength and durability.

[0006] To address the above problems, the present invention provides the following technical solution.

[0007] In a first aspect, the present invention provides a carbonate rock powder-based mineral admixture comprising the following components by mass percentage: 50%–60% carbonate rock powder, 30%–40% biomass ash, and 10% red mud; the sum of the mass percentages of all components is 100%.

[0008] The carbonate rock powder-based mineral admixture of the present invention has, but is not limited to, the following beneficial effects compared with the prior art: The carbonate rock powder-based mineral admixture of the present invention combines carbonate rock powder, biomass ash and red mud, three major solid wastes, and successfully solves the inherent defects of using single carbonate rock powder in concrete, realizing the high-quality and large-scale utilization of multi-source solid waste.

[0009] In terms of technical performance, by controlling the effective content and physical properties of each component, and based on the nucleation, chemical, and filling effects of carbonate rock powder, the active silica, particle morphology, and internal curing effects of biomass ash, and the active aluminum / iron and alkaline environment of red mud, a multi-scale synergistic effect of chemical and physical processes far exceeding that of simple mixing is achieved. Firstly, when forming a composite system with cement, it fundamentally activates and enhances the hydration activity of the composite system. The alkaline environment provided by red mud ensures that the composite system will not suffer from insufficient alkalinity due to the large-scale replacement of cement, stimulating the activity of the silica components of biomass ash and the alumina and iron oxide components of red mud. Meanwhile, the CaCO3 / CaCO3·MgCO3 in carbonate rock powder can provide a calcium source, promoting the formation of hydrated calcium silicate (CSH). The provided CaCO3 and MgCO3, along with the alumina and iron oxide components, can respectively promote the formation of calcium aluminate products (generally with the chemical formula: 4CaO). (Al,Fe)2O3 xCO2 yH2O) and hydrotalcite products (generally with the chemical formula: Mg2(Al,Fe)(OH)6(CO3)0.5(H2O) 1.5 Meanwhile, the nucleation effect of carbonate rock powder and the internal curing effect of biomass ash accelerate and optimize the hydration process of the entire system, resulting in an increase in the amount of hydration products in the system. This effectively overcomes the core problems of low hydration activity of carbonate rock powder itself and the sharp drop in strength and durability due to dilution effect when the dosage is large.

[0010] Secondly, the continuous particle size distribution of biomass ash, carbonate rock powder, and red mud achieves dense particle packing, ensuring not only the workability of fresh concrete but also making the hardened concrete structure extremely dense, thus improving its mechanical strength, impermeability, and erosion resistance. Finally, addressing the potential risks of high alkali and heavy metal ion leaching from red mud and biomass ash, the generated calcium aluminate and hydrotalcite products, with their layered structures, can effectively dissolve heavy metal ions and adsorb OH-.- Cl - The presence of anions reduces the risk of heavy metal ion leaching and alkali-aggregate reaction, enhances resistance to chloride ion penetration, and ensures excellent volume stability and long-term service safety of concrete.

[0011] In terms of economy and application, all core components are industrial by-products or wastes that urgently need to be processed. Their acquisition cost is far lower than that of cement and traditional admixtures such as fly ash and mineral powder, making the concrete prepared from them significantly more economically competitive. Preferably, the carbonate rock powder is stone chips and powder produced during the process of crushing carbonate rocks into artificial aggregates, and the stone chips and powder are ground in a ball mill to a specific surface area of ​​350 m². 2 / kg~400m 2 / kg; the sum of the mass percentages of CaCO3 and CaCO3·MgCO3 in the mineral composition of the carbonate rock powder is ≥90%.

[0012] Specifically, by optimizing and controlling the fineness and mineral composition of carbonate rock powder, its stable filling, nucleation, and chemical effects in the mineral admixture system can be effectively ensured: its suitable specific surface area allows it to form a continuous particle size distribution with biomass ash and red mud in the system, which helps to achieve close particle packing, improve the workability of fresh concrete, and increase the density of hardened concrete; the high content of carbonate minerals provides the system with sufficient calcium source, and under the synergistic effect of the alkaline environment provided by red mud and the active silica provided by biomass ash, it promotes the formation of calcium silicate hydrate (CSH), calcium aluminate carbohydrate, and hydrotalcite products.

[0013] Preferably, the carbonate rock is any one or a combination of pure limestone, dolomitic limestone, calcareous dolomite, and pure dolomite.

[0014] Specifically, limiting the carbonate rocks to any one or more combinations of pure limestone, dolomitic limestone, calcareous dolomite, and pure dolomite ensures that the sum of the mass percentages of CaCO3 and CaCO3·MgCO3 in the obtained carbonate rock powder is ≥90%, guaranteeing the full utilization of nucleation, chemical, and filling effects. Simultaneously, the MgCO3 introduced from the dolomitic component, when reacting synergistically with the active aluminum / iron components in the red mud, can promote the formation of hydrotalcite-like products, enhancing the ability to solidify heavy metal ions and harmful anions. Furthermore, the aforementioned carbonate rocks are widely available and generate large amounts of waste, facilitating large-scale integrated application and reducing production costs.

[0015] Preferably, the biomass ash is biomass power plant ash, which includes ash residue formed by burning agricultural and forestry waste at a high temperature of 700℃~800℃, and the mass percentage of SiO2 in the ash residue is ≥75%.

[0016] Specifically, using power plant ash can realize the resource utilization of solid waste and reduce costs; high-temperature combustion can ensure that biomass ash has highly active siliceous components and ensure its suitable particle morphology and specific surface area characteristics, exerting an internal curing effect, and forming a continuous particle size distribution with carbonate rock powder and red mud; the high SiO2 content can give full play to the volcanic ash effect, and work synergistically with the alkaline environment provided by red mud and the calcium source provided by carbonate rock powder to promote the formation of hydrated calcium silicate gel.

[0017] Preferably, the agricultural and forestry waste is any one or a combination of two of straw and rice husks.

[0018] Specifically, using any one or a combination of two of straw and rice husks as raw materials to prepare bioash has the advantages of wide availability, low cost and stable composition.

[0019] Preferably, the specific surface area of ​​the biomass ash is 70 m². 2 / kg~100m 2 / kg.

[0020] Specifically, controlling the fineness of biomass ash can enable it to exert a better synergistic effect of physical filling and internal curing when it is particle size-graded with carbonate rock powder and red mud.

[0021] Preferably, the red mud is Bayer process red mud, and the sum of the mass percentages of Al2O3 and Fe2O3 in the Bayer process red mud is ≥70%.

[0022] Specifically, the high content of active aluminum and iron components can synergistically interact with the calcium source provided by carbonate rock powder and the active silica provided by biomass ash to generate hydration products such as calcium aluminate and hydrotalcite, thereby improving the mechanical strength and durability of concrete and reducing the risk of heavy metal leaching.

[0023] Preferably, the red mud is in powder form and has a specific surface area ≥350m². 2 / kg.

[0024] Specifically, red mud particles with high specific surface area can not only form a tighter continuous particle size distribution with carbonate rock powder and biomass ash, but also help their active aluminum and iron components to be released more fully in an alkaline environment, promoting the formation of hydration products such as calcium aluminate and hydrotalcite.

[0025] Secondly, the present invention also discloses a preparation method for preparing the carbonate rock powder-based mineral admixture as described above, comprising the following steps: mixing carbonate rock powder, biomass ash and red mud evenly according to the weight ratio to obtain the carbonate rock powder-based mineral admixture. Specifically, the preparation process is simple and easy to industrialize and scale up; the invented admixture has good performance and can replace some traditional mineral admixtures, which is in line with the green and low-carbon development strategy and helps the cement and concrete industry reduce solid waste emissions, save energy and protect the environment, and reduce costs and increase efficiency. Attached Figure Description

[0026] Figure 1 This is a comparison graph showing the change in compressive strength of concrete over age in Examples 4-6 and Comparative Examples 4-9 of the present invention. Figure 2 These are comparative curves showing the changes in drying shrinkage properties of concrete in Examples 4-6 and Comparative Examples 4-9 of this invention as a function of age. Detailed Implementation

[0027] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0028] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0029] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0030] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0031] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0032] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased commercially or prepared by existing methods. For example, the chemical composition of carbonate rock powder, biomass ash, and red mud involved in the following examples and comparative examples is shown in Table 1. Table 1 is as follows: Table 1

[0033] Among them, carbonate rock powder is the stone chips and powder produced during the process of crushing carbonate rocks (a combination of dolomitic limestone and calcareous dolomite in a 1:1 mass ratio) into artificial aggregate. These stone chips and powder are ground in a ball mill to a specific surface area of ​​365 m². 2 / kg, of which the sum of the mass percentages of CaCO3 and CaCO3·MgCO3 in the carbonate rock powder is 99.1%; Biomass ash is the ash residue formed by burning agricultural and forestry waste such as straw and rice husks at a high temperature of 785℃. The mass percentage of SiO2 in the ash residue is 94.33%; the specific surface area of ​​biomass ash is 85 m². 2 / kg.

[0034] The red mud is Bayer process red mud, with a combined mass percentage of 74.1% for Al₂O₃ and Fe₂O₃; the red mud is in powder form and has a specific surface area of ​​4000 m². 2 / kg.

[0035] Example 1 This embodiment discloses a carbonate rock powder-based mineral admixture, which is prepared according to the following steps: 50 kg of carbonate rock powder, 40 kg of biomass ash and 10 kg of red mud are prepared according to the weight ratio and added together into a mixing kettle. The mixing speed is 100 r / min, and the mixture is rotated clockwise and counterclockwise for 15 min each. The mixture is then mixed evenly to obtain the carbonate rock powder-based mineral admixture.

[0036] Example 2 This embodiment discloses a carbonate rock powder-based mineral admixture, which is prepared according to the following steps: 55 kg of carbonate rock powder, 35 kg of biomass ash and 10 kg of red mud are prepared according to the weight ratio, and added together in a mixing tank and mixed evenly to obtain the carbonate rock powder-based mineral admixture.

[0037] Example 3 This embodiment discloses a carbonate rock powder-based mineral admixture, which is prepared according to the following steps: 60 kg of carbonate rock powder, 30 kg of biomass ash and 10 kg of red mud are prepared according to the weight ratio, and added together in a mixing tank and mixed evenly to obtain the carbonate rock powder-based mineral admixture.

[0038] Comparative Example 1 This comparative example discloses a carbonate rock powder-based mineral admixture, which is prepared according to the following steps: 60 kg of carbonate rock powder and 40 kg of biomass ash are prepared according to the weight ratio, and then added to a mixing tank and mixed evenly to obtain the carbonate rock powder-based mineral admixture.

[0039] Comparative Example 2 This comparative example discloses a carbonate rock powder-based mineral admixture, which is prepared according to the following steps: 70 kg of carbonate rock powder, 20 kg of biomass ash and 10 kg of red mud are prepared according to the weight ratio, and added together in a mixing tank and mixed evenly to obtain the carbonate rock powder-based mineral admixture.

[0040] Comparative Example 3 This comparative example discloses a carbonate rock powder-based mineral admixture, which is prepared according to the following steps: 40 kg of carbonate rock powder, 50 kg of biomass ash and 10 kg of red mud are prepared according to the weight ratio, and added together in a mixing tank and mixed evenly to obtain the carbonate rock powder-based mineral admixture.

[0041] Analysis of the carbonate rock powder-based mineral admixtures of Examples 1-3 and Comparative Examples 1-3 shows that the only difference between the groups is the mass percentage of each component in the carbonate rock powder-based mineral admixture. To more clearly and intuitively understand the differences, the mass percentage of each component in the carbonate rock powder-based mineral admixtures of Examples 1-3 and Comparative Examples 1-3 is listed in Table 2, as follows: Table 2

[0042] Analysis of the data in Table 2 shows that in the carbonate rock powder-based mineral admixtures of Examples 1-3, the mass percentage of carbonate rock powder is 50%-60%, the mass percentage of biomass ash is 30%-40%, and the mass percentage of red mud is 10%. In contrast, in Comparative Examples 1-3, Comparative Example 1 does not contain red mud, the mass percentage of carbonate rock powder in Comparative Example 2 is higher than that in Examples 1-3, and the mass percentage of carbonate rock powder in Comparative Example 3 is lower than that in Examples 1-3.

[0043] Example 4 This embodiment discloses a concrete prepared according to the following steps: 440 kg of cement composite (containing 308 kg of cement and 132 kg of carbonate rock powder-based mineral admixture from Example 1), 680 kg of sand, 1080 kg of stone, 154 kg of water and 5.18 kg of water-reducing agent are added together to a mixing tank and mixed evenly to obtain concrete.

[0044] In this embodiment, the cement used is P·O 42.5 ordinary Portland cement produced by Conch Cement, the sand is river sand with a fineness modulus of 2.6, the stone is crushed stone of continuous grade of 5-25mm, the water is tap water, and the water-reducing agent is polycarboxylate high-performance water-reducing agent produced by Zhaojia Technology.

[0045] Example 5 Compared with Example 4, the only difference is that the carbonate rock powder-based mineral admixture of Example 1 is replaced with the carbonate rock powder-based mineral admixture of Example 2; all other conditions are exactly the same as in Example 4, resulting in concrete.

[0046] Example 6 Compared with Example 4, the only difference is that the carbonate rock powder-based mineral admixture of Example 1 is replaced with the carbonate rock powder-based mineral admixture of Example 3; all other conditions are exactly the same as those of Example 4, resulting in concrete.

[0047] Comparative Example 4 Compared with Example 4, the only difference is that the carbonate rock powder-based mineral admixture of Example 1 in the cement composite is replaced with the carbonate rock powder-based mineral admixture of Comparative Example 1; all other conditions are exactly the same as in Example 4, resulting in concrete.

[0048] Comparative Example 5 Compared with Example 4, the only difference is that the carbonate rock powder-based mineral admixture of Example 1 in the cement composite is replaced with the carbonate rock powder-based mineral admixture of Comparative Example 2; all other conditions are exactly the same as in Example 4, resulting in concrete.

[0049] Comparative Example 6 Compared with Example 4, the only difference is that the carbonate rock powder-based mineral admixture of Example 1 in the cement composite is replaced with the carbonate rock powder-based mineral admixture of Comparative Example 3; all other conditions are exactly the same as in Example 4, resulting in concrete.

[0050] Comparative Example 7 Compared to Example 4, the only difference is that the cement composite is replaced with cement; all other conditions remain exactly the same as in Example 4, resulting in concrete.

[0051] The concrete used in this comparative example is the benchmark concrete in the prior art.

[0052] Comparative Example 8 Compared with Example 4, the only difference is that 308 kg of cement in the cement composite and 132 kg of carbonate rock powder-based mineral admixture in Example 1 are replaced with 374 kg of cement and 66 kg of carbonate rock powder (the content of carbonate rock powder is 15 wt%), respectively; all other conditions are exactly the same as in Example 4, and the final concrete is produced.

[0053] Comparative Example 9 Compared with Example 4, the only difference is that the carbonate rock powder-based mineral admixture in the cement composite of Example 1 is replaced with carbonate rock powder (the content of carbonate rock powder is 30 wt%); all other conditions are exactly the same as in Example 4, resulting in concrete.

[0054] Performance tests were conducted on the concrete samples from Examples 4-6 and Comparative Examples 4-9. The test items and methods were as follows: Slump: The test was conducted in accordance with the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" (GB / T50080-2016), and the cohesiveness, water retention and viscosity of the concrete after slump were observed. Chloride ion migration coefficient: The RCM method was used in accordance with the "Standard for Test Methods of Long-Term Performance and Durability of Concrete" (GBT50082-2024). Compressive strength: Tested in accordance with the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T50081-2019); Shrinkage resistance: The shrinkage test was conducted in accordance with the "Standard for Test Methods of Long-term Performance and Durability of Concrete" (GBT50082-2024).

[0055] The test results for collapse degree and chloride ion migration coefficient are listed in Table 3, as follows: Table 3

[0056] Regarding the test results for compressive strength, as follows: Figure 1 As shown; the test results regarding shrinkage resistance are as follows: Figure 2 As shown.

[0057] For Table 3, Figure 1 and Figure 2 By analyzing the data, we can find that: 1. Comparing Example 4 with Comparative Example 9, it can be seen that the only difference between Example 4 and Comparative Example 9 is that pure carbonate rock powder was used in Comparative Example 9 instead of the carbonate rock powder-based mineral admixture in Example 4. In this case, compared with Comparative Example 9, the concrete of Example 4 has a significantly higher slump, a larger chloride ion migration coefficient, and a higher compressive strength. This shows that in cementitious composites, carbonate rock powder-based mineral admixtures can improve the slump, chloride ion migration coefficient, and compressive strength of concrete compared with pure carbonate rock powder. Moreover, the carbonate rock powder-based mineral admixture introduced into the cementitious composite of Example 4 can not only ensure that the slump of the concrete is similar to that of the reference concrete of Comparative Example 7, but also significantly improve the cohesiveness and water retention, resulting in good workability. At the same time, the compressive strength is similar to or even higher than that of Comparative Example 7, especially the later strength. The chloride ion migration coefficient is significantly lower than that of Comparative Example 7, indicating a significant improvement in resistance to chloride ion penetration.

[0058] The difference between the results of Example 4 and Example 9 may be due to the following: In Example 4, the cement composite and carbonate rock powder-based mineral admixture contained 50 wt% carbonate rock powder, 40% biomass ash, and 10% red mud. At this time, the carbonate rock powder content in the cement composite was 15 wt%, and it also contained biomass ash and red mud. In Comparative Example 9, the carbonate rock powder content in the cement composite was 30 wt%, and it did not contain biomass ash and red mud. This shows that when the carbonate rock powder in the cement composite is at a certain dosage (15 wt%) and contains biomass ash and red mud, it can improve the slump, chloride ion migration coefficient, and compressive strength of concrete. However, when the carbonate rock powder content in the cement composite is too high (30 wt%) and does not contain biomass ash and red mud, it will cause a drastic loss of slump in the fresh concrete and lead to a significant increase in viscosity.

[0059] 2. Comparing Example 4 with Comparative Example 6, it can be seen that the only difference between Example 4 and Comparative Example 6 is that in Example 4, the content of carbonate rock powder in the carbonate rock powder-based mineral admixture in the cement composite is 50 wt%, and the content of biomass ash is 40 wt%; while in Comparative Example 6, the content of carbonate rock powder in the carbonate rock powder-based mineral admixture in the cement composite is 40 wt%, and the content of biomass ash is 50 wt%. At this time, compared with Comparative Example 6, the concrete of Example 4 has a significantly higher slump, a larger chloride ion migration coefficient, and a higher compressive strength. This shows that when the content of carbonate rock powder in the carbonate rock powder-based mineral admixture is too low, the carbonate rock powder-based mineral admixture will cause a significant decrease in the slump of the concrete.

[0060] 3. Meanwhile, the drying shrinkage performance of the concrete in Example 4 was significantly lower than that in Comparative Example 6. This indicates that when the content of carbonate rock powder in the carbonate rock powder-based mineral admixture is too low, it is detrimental to the resistance to drying shrinkage, which is very unfavorable to the volume stability of the concrete.

[0061] 4. Comparing Example 4 with Comparative Examples 4-6, it can be seen that the absence of red mud in the carbonate rock powder-based mineral admixture, and the excessively high or low proportion of carbonate rock powder, will lead to a significant reduction in the strength and chloride ion penetration resistance of cement concrete, making it difficult to guarantee the strength performance and durability requirements of concrete. Compared with Comparative Example 7, which does not contain any carbonate rock powder, and Comparative Examples 8-9, which only contain carbonate rock powder, Comparative Examples 3-6 also reduced drying shrinkage and improved drying shrinkage resistance, but the effect was not as good as that of Examples 3-6, which contained carbonate rock powder-based mineral admixtures with a reasonable component ratio.

[0062] In summary, a carbonate rock powder-based mineral admixture formulated with 50%–60% carbonate rock powder, 30%–40% biomass ash, and 10% red mud can give concrete good workability, strength, volume stability, and durability. It solves the problems of low hydration activity and significant strength reduction when carbonate rock powder is used alone, and realizes the high-quality and large-scale utilization of carbonate rock powder, biomass ash, and red mud, thereby reducing the cost of concrete.

[0063] It is important to note that the dosage of each component in carbonate rock powder-based mineral admixtures must be strictly controlled; the absence of red mud will significantly reduce the activity of the system, resulting in insufficient strength and durability, making it difficult to meet the requirements; too low or too high a proportion of carbonate rock powder will prevent the system from playing its comprehensive role effectively, making it difficult to ensure that the concrete has good workability, mechanical properties and durability.

[0064] The foregoing has described several embodiments of the present invention in detail, but these descriptions are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A carbonate rock powder-based mineral admixture, characterized in that, It includes the following components by mass percentage: 50%–60% carbonate rock powder, 30%–40% biomass ash, and 10% red mud; the sum of the mass percentages of all components is 100%. The carbonate rock powder refers to the stone chips and powder produced during the process of crushing carbonate rocks into artificial aggregates. The stone chips and powder are ground in a ball mill to a specific surface area of ​​350 m². 2 / kg~400m 2 / kg; the sum of the mass percentages of CaCO3 and CaCO3·MgCO3 in the mineral composition of the carbonate rock powder is ≥90%; The carbonate rock is a combination of dolomitic limestone and calcareous dolomite in a mass ratio of 1:

1. The red mud is Bayer process red mud, and the sum of the mass percentages of Al2O3 and Fe2O3 in the Bayer process red mud is ≥70%.

2. The carbonate rock powder-based mineral admixture according to claim 1, characterized in that, The biomass ash is biomass power plant ash, which includes ash residue formed by burning agricultural and forestry waste at a high temperature of 700℃~800℃, and the mass percentage of SiO2 in the ash residue is ≥75%.

3. The carbonate rock powder-based mineral admixture according to claim 2, characterized in that, The agricultural and forestry waste is any one or a combination of two of the following: straw and rice husks.

4. The carbonate rock powder-based mineral admixture according to claim 2, characterized in that, The specific surface area of ​​the biomass ash is 70 m². 2 / kg~100m 2 / kg.

5. The carbonate rock powder-based mineral admixture according to claim 1, characterized in that, The red mud is in powder form and has a specific surface area ≥350m². 2 / kg.

6. A preparation method for preparing the carbonate rock powder-based mineral admixture as described in any one of claims 1 to 5, characterized in that, The process includes the following steps: mixing carbonate rock powder, biomass ash and red mud evenly according to the mass percentage to obtain carbonate rock powder-based mineral admixture.

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