Solid waste-based cementitious material and method for preparing the same

Abstract

This invention relates to the field of cementitious materials technology, and provides a solid waste-based cementitious material and its preparation method. The solid waste-based cementitious material of this invention comprises the following raw materials: solid waste mixture A and solid waste mixture B; the solid waste mixture A in the solid waste-based cementitious material has a weight percentage of 70-90%; solid waste mixture A includes at least one selected from Bayer process red mud, blast furnace slag, fly ash, steel slag, and fly ash; solid waste mixture B includes at least one selected from papermaking white mud, carbide slag, conversion furnace slag, magnesium slag, desulfurization gypsum, and phosphogypsum. This invention improves the reactivity of solid wastes through the compounding and mechanical activation of different solid wastes, thus preparing a highly active gel material. This gel material has high mechanical properties. Furthermore, the all-solid waste-based gel does not generate new waste during preparation, making it environmentally friendly and providing a new solution for improving the comprehensive utilization rate of solid waste.

Description

Technical Field

[0001] This invention relates to the field of cementitious materials technology, and in particular to a solid waste-based cementitious material and its preparation method. Background Technology

[0002] With the continuous advancement of industrialization, key industries such as alumina preparation, steelmaking, metallurgy, power generation, and chemical production have achieved rapid development, providing strong support for national economic growth. However, this has also generated a large amount of industrial solid waste. The proper disposal and resource utilization of this waste has become a key bottleneck restricting the healthy and sustainable development of related industries.

[0003] Red mud, as a major industrial solid waste generated by the alumina industry, presents particularly prominent challenges in its treatment. Besides red mud, various other industrial solid wastes, such as steel slag, fly ash, blast furnace slag, and waste gypsum (mainly phosphogypsum and desulfurization gypsum), also suffer from large-scale stockpiling and low utilization rates. Furthermore, fly ash, calcium carbide slag, converter steel slag, and magnesium slag are also commonly found to be stored and treated in large quantities.

[0004] The open-air stockpiling and makeshift landfilling of hundreds of millions of tons of industrial solid waste has become a major contributing factor to ecological and environmental problems and public safety issues. Heavy metal ions, soluble salts, and other harmful substances in the waste residue are leached and seeped in by rainwater, polluting soil and groundwater, damaging farmland ecosystems and drinking water safety. Dust from stockpiles carries particulate matter and toxic particles, exacerbating air pollution and harming human respiratory health. Improper stockpiling can also easily trigger geological disasters such as landslides and collapses, and the long degradation cycle of the waste residue causes long-term irreversible damage to regional ecosystems.

[0005] Faced with the increasingly severe situation of solid waste management, the country attaches great importance to the comprehensive management of industrial solid waste, solves the disposal problems of various types of industrial solid waste, improves the comprehensive utilization rate, and promotes its transformation towards high value and resource utilization. This is not only an inevitable requirement for implementing the national ecological and environmental protection strategy, but also a key measure to promote the green and sustainable development of related industries and realize resource recycling. It has important practical significance and strategic value for alleviating resource shortages, protecting the ecological environment, and ensuring human safety. Summary of the Invention

[0006] To address the aforementioned technical deficiencies, this invention provides a solid waste-based cementitious material and its preparation method. This invention adjusts the proportions of various solid wastes and then uses a mechanical co-activation method to stimulate the potential reactivity of the solid wastes, thereby preparing a high-performance cementitious material. This material can, to a certain extent, replace cement products, achieving the harmless treatment and resource utilization of solid waste.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a solid waste-based cementitious material, comprising the following raw materials: solid waste mixture A and solid waste mixture B;

[0009] The solid waste mixture A in the solid waste-based cementitious material has a weight percentage of 70-90%;

[0010] The solid waste mixture A includes at least one of Bayer red mud, blast furnace slag, fly ash, steel slag, and fly ash.

[0011] The solid waste mixture B includes at least one of papermaking sludge, carbide slag, conversion furnace slag, magnesium slag, desulfurization gypsum, and phosphogypsum.

[0012] Preferably, the solid waste mixture A comprises the following raw materials in parts by weight: 0-45 parts Bayer red mud, 15-65 parts blast furnace slag, 0-35 parts fly ash, 0-55 parts steel slag, and 0-75 parts fly ash.

[0013] Preferably, the solid waste mixture B comprises the following raw materials in parts by weight: 0-75 parts phosphogypsum, 0-65 parts desulfurization gypsum, 0-55 parts carbide slag, 0-45 parts papermaking sludge, 0-45 parts magnesium slag, and 0-45 parts conversion furnace slag.

[0014] Preferably, the solid waste mixture A comprises the following raw materials in parts by weight: 50 parts blast furnace slag, 30 parts fly ash, 20 parts steel slag, and 10 parts fly ash;

[0015] The solid waste mixture B comprises the following raw materials in parts by weight: 50 parts phosphogypsum, 40 parts carbide slag, and 10 parts papermaking sludge.

[0016] Preferably, the solid waste mixture A comprises the following raw materials in parts by weight: 10 parts Bayer red mud, 60 parts blast furnace slag, 10 parts steel slag, and 20 parts fly ash;

[0017] The solid waste mixture B comprises the following raw materials in parts by weight: 50 parts desulfurized gypsum and 50 parts carbide slag.

[0018] Preferably, the Bayer process red mud comprises the following components by mass fraction: Fe2O3 30-40%, Al2O3 10-30%, SiO2 5-25%, CaO 2-10%, Na2O 2-10%, TiO2 0-5%;

[0019] The blast furnace slag comprises the following components by mass fraction: Fe2O3 0~2.5%, Al2O3 10~20%, SiO2 30~45%, CaO 30~50%, MgO 3~10%;

[0020] The fly ash comprises the following components by mass fraction: Fe2O3 3~15%, Al2O3 10~40%, SiO2 40~70%, CaO 2~10%;

[0021] The steel slag comprises the following components by mass fraction: Fe2O3 10~30%, Al2O3 3~10%, SiO2 10~25%, CaO 40~60%, MnO 1~5%;

[0022] The fly ash comprises the following components by mass fraction: Fe2O3 0~10%, Al2O3 25~45%, SiO2 40~60%, CaO 2~10%, K2O 1~5%, TiO2 0~5%;

[0023] The papermaking sludge comprises the following components by mass fraction: CaCO3 85~90%, Ca(OH)2 4~5%, SiO2 3~7%, CaO 2-4%;

[0024] The carbide slag comprises the following components by mass fraction: Ca(OH)2 78~90%, CaO 2~5%, CaCO3 5~10%, SiO2 1~8%;

[0025] The conversion slag comprises the following components by mass fraction: CaO 40-60%, SiO2 10-20%, Fe2O3 20-30%, MgO 3-10%;

[0026] The magnesium slag comprises the following components by mass fraction: CaO 45~55%, SiO2 25~35%, MgO 6~10%, Al2O3 2~5%, Fe2O3 3~9%, and CaF2 1~3%.

[0027] Secondly, the present invention also provides a method for preparing the aforementioned solid waste-based cementitious material, comprising the following steps:

[0028] Solid waste mixture A and solid waste mixture B are placed in a ball mill and ball-milled to obtain solid waste-based cementitious material.

[0029] Preferably, the ball milling speed is 100~1000 r / min and the ball milling time is 2~100 min.

[0030] Preferably, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B during ball milling is (5~20):1.

[0031] Thirdly, the present invention also provides a mortar material, wherein the preparation method of the mortar material is as follows: mixing cementitious material, sand and water, and then curing to obtain the mortar material;

[0032] The cementing material is either the solid waste-based cementing material or the solid waste-based cementing material prepared by the preparation method.

[0033] The solid waste-based cementitious material and its preparation method of the present invention have the following advantages compared with the prior art:

[0034] 1. The solid waste-based gelling material of this invention improves the reactivity of solid waste through compounding and mechanical activation of different solid wastes, thus preparing a highly active gel material. This gel material exhibits high mechanical properties. Furthermore, the all-solid waste-based gel generates virtually no new waste (including gaseous, liquid, and solid waste) during its preparation, making it environmentally friendly and providing a new solution for improving the comprehensive utilization rate of solid waste.

[0035] 2. The solid waste-based cementitious material of the present invention, by optimizing the proportion of each solid waste, can achieve a compressive strength of 52.1~52.2MPa after 28 days of curing, exhibiting excellent mechanical properties; and after 28 days of curing, in two corrosive media, Na2SO4 and MgSO4, the corrosion resistance coefficient K1 at 90 days is between 0.95~1.33 and the corrosion resistance coefficient K2 at 180 days is between 0.92~1.55, exhibiting excellent resistance to sulfate and seawater erosion. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 The XRD patterns are of the mortar specimens obtained after curing for 3 days, 7 days, and 28 days in Example 5.

[0038] Figure 2 The TG curves are for the cementitious material before and after mechanical activation in Example 5, and for the mortar specimens obtained after standard curing for 28 days in Example 5.

[0039] Figure 3 The DTG curves are for the cementitious material before and after mechanical activation in Example 5, and for the mortar specimens obtained after standard curing for 28 days in Example 5.

[0040] Figure 4The images show SEM images of the mortar specimens obtained after 28 days of standard curing in Example 5, SEM images of the mortar specimens obtained after 28 days of standard curing immersed in seawater for 180 days, and SEM images of the mortar specimens obtained after 28 days of standard curing immersed in solution and MgSO4 solution for 180 days. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist 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 construed 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 that range. For example, it should be considered that the range description from 1 to 6 has 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., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0043] This application provides a solid waste-based cementitious material, comprising the following raw materials: solid waste mixture A and solid waste mixture B;

[0044] The solid waste mixture A in solid waste-based cementitious materials accounts for 70-90% by weight;

[0045] Solid waste mixture A includes at least one of Bayer red mud, blast furnace slag, fly ash, steel slag, and fly ash;

[0046] Solid waste mixture B includes at least one of papermaking sludge, carbide slag, conversion furnace slag, magnesium slag, desulfurization gypsum, and phosphogypsum.

[0047] In some embodiments, solid waste mixture A comprises the following raw materials in parts by weight: 0-45 parts Bayer red mud, 15-65 parts blast furnace slag, 0-35 parts fly ash, 0-55 parts steel slag, and 0-75 parts fly ash.

[0048] In some embodiments, solid waste mixture B comprises the following raw materials in parts by weight: 0-75 parts phosphogypsum, 0-65 parts desulfurization gypsum, 0-55 parts carbide slag, 0-45 parts papermaking sludge, 0-45 parts magnesium slag, and 0-45 parts conversion furnace slag.

[0049] In some embodiments, solid waste mixture A comprises the following raw materials in parts by weight: 50 parts blast furnace slag, 30 parts fly ash, 20 parts steel slag, and 10 parts fly ash;

[0050] Solid waste mixture B comprises the following raw materials in parts by weight: 50 parts phosphogypsum, 40 parts carbide slag, and 10 parts papermaking sludge.

[0051] In some embodiments, solid waste mixture A comprises the following raw materials in parts by weight: 10 parts Bayer red mud, 60 parts blast furnace slag, 10 parts steel slag, and 20 parts fly ash;

[0052] Solid waste mixture B comprises the following raw materials in parts by weight: 50 parts desulfurized gypsum and 50 parts carbide slag.

[0053] In some embodiments, Bayer process red mud comprises the following components by mass fraction:

[0054] Fe2O3 30~40%, Al2O3 10~30%, SiO2 5~25%, CaO 2~10%, Na2O 2~10%, TiO2 0~5%;

[0055] Blast furnace slag comprises the following components by mass fraction: Fe2O3 0~2.5%, Al2O3 10~20%, SiO2 30~45%, CaO 30~50%, MgO 3~10%;

[0056] Fly ash comprises the following components by mass fraction: Fe2O3 3~15%, Al2O3 10~40%, SiO2 40~70%, CaO 2~10%;

[0057] Steel slag comprises the following components by mass fraction: Fe2O3 10~30%, Al2O3 3~10%, SiO2 10~25%, CaO 40~60%, MnO 1~5%;

[0058] Fly ash comprises the following components by mass fraction: Fe2O3 0~10%, Al2O3 25~45%, SiO2 40~60%, CaO 2~10%, K2O 1~5%, TiO2 0~5%;

[0059] The papermaking sludge comprises the following components by mass fraction: CaCO3 85~90%, Ca(OH)2 4~5%, SiO2 3~7%, CaO 2-4%;

[0060] Calcium carbide slag comprises the following components by mass fraction: Ca(OH)₂ 78~90%, CaO 2~5%, CaCO₃ 5~10%, SiO₂ 1~8%;

[0061] The conversion furnace slag comprises the following components by mass fraction: CaO 40~60%, SiO2 10~20%, Fe2O3 20~30%, MgO 3~10%;

[0062] Magnesium slag comprises the following components by mass fraction: CaO 45~55%, SiO2 25~35%, MgO 6~10%, Al2O3 2~5%, Fe2O3 3~9%, and CaF2 1~3%.

[0063] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned solid waste-based cementitious material, comprising the following steps:

[0064] Solid waste mixture A and solid waste mixture B are placed in a ball mill and ball-milled to obtain solid waste-based cementitious material.

[0065] In some embodiments, solid waste mixture A and solid waste mixture B are placed in a ball mill, ball milling media are added, and ball milling is performed; the ball milling speed is 100~1000 r / min, and the ball milling time is 2~100 min.

[0066] In some embodiments, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B during ball milling is (5~20):1; the ball milling media are zirconia balls or stainless steel balls.

[0067] This invention relates to the resource utilization of various solid wastes. By compounding and mechanically activating different solid wastes, the reactivity of the solid wastes is improved, resulting in the preparation of highly active gel materials. These gel materials possess high mechanical properties. Furthermore, the all-solid waste-based gel does not generate new waste (including gaseous, liquid, and solid wastes) during its preparation process, making it environmentally friendly and providing a new solution for improving the comprehensive utilization rate of solid waste.

[0068] Based on the same inventive concept, the present invention also provides a mortar material, the preparation method of which is as follows: mixing cementitious material, sand and water, and then curing to obtain the mortar material;

[0069] The cementing material is either the solid waste-based cementing material mentioned above or the solid waste-based cementing material prepared by the above preparation method.

[0070] Specifically, the standard maintenance temperature is 18~22℃ and the relative humidity is above 95%RH.

[0071] In some embodiments, the mass ratio of cementitious material, sand and water is (1~2):(3~4):(0.5~1), and the sand is standard sand.

[0072] The following detailed embodiments further illustrate the solid waste-based cementitious material and its preparation method. This section, in conjunction with specific embodiments, further explains the content of the present invention, but should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments 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.

[0073] In the following embodiments, the Bayer process red mud comprises the following components by mass fraction: Fe2O3 38%, Al2O3 21%, SiO2 18%, CaO 8%, Na2O 9%, TiO2 5%;

[0074] Blast furnace slag comprises the following components by mass fraction: Fe2O3 2%, Al2O3 16%, SiO2 36%, CaO 38%, MgO 8%;

[0075] Fly ash comprises the following components by mass fraction: Fe2O3 10%, Al2O3 22%, SiO2 60%, CaO 8%;

[0076] Steel slag comprises the following components by mass fraction: Fe2O3 22%, Al2O3 5%, SiO2 18%, CaO 52%, MnO 3%;

[0077] Fly ash comprises the following components by mass fraction: Fe2O3 6%, Al2O3 32%, SiO2 52%, CaO 4%, K2O 3%, TiO2 3%;

[0078] The papermaking sludge comprises the following components by mass fraction: CaCO3 88%, Ca(OH)2 5%, SiO2 5%, CaO 2%;

[0079] Calcium carbide slag comprises the following components by mass fraction: Ca(OH)₂ 85%, CaO 3%, CaCO₃ 7%, SiO₂ 25%;

[0080] The conversion furnace slag comprises the following components by mass fraction: CaO 52%, SiO2 16%, Fe2O3 24%, MgO 8%;

[0081] Magnesium slag comprises the following components by mass fraction: CaO 50%, SiO2 28%, MgO 8%, Al2O3 4%, Fe2O3 7%, and CaF2 3%.

[0082] In the following examples, the desulfurized gypsum and phosphogypsum were sourced from Guangxi Guihe New Building Materials Co., Ltd.

[0083] Example 1

[0084] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0085] In the solid waste-based cementitious material, solid waste mixture A accounts for 70% by weight and solid waste mixture B accounts for 30% by weight.

[0086] Solid waste mixture A includes the following raw materials by weight: 40 parts Bayer red mud, 30 parts blast furnace slag, 20 parts fly ash, and 10 parts steel slag.

[0087] Solid waste mixture B includes the following raw materials in parts by weight: 40 parts phosphogypsum, 40 parts carbide slag, 10 parts papermaking mud, and 10 parts magnesium slag.

[0088] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0089] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 100 r / min, and the ball milling time was 100 min;

[0090] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0091] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material standard sand, sand and water prepared in Example 1 are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20℃ and a relative humidity of 98%RH for 3 days. The compressive strength and flexural strength of the mortar specimens are measured on the 7th day and the 28th day.

[0092] The initial and final setting times of the gel material were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater erosion and sulfate erosion resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0093] Example 2

[0094] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0095] In the solid waste-based cementitious material, solid waste mixture A accounts for 80% by weight and solid waste mixture B accounts for 20% by weight.

[0096] Solid waste mixture A includes the following raw materials by weight: 10 parts steel slag, 40 parts blast furnace slag, 10 parts fly ash, and 40 parts fly ash.

[0097] Solid waste mixture B includes the following raw materials in parts by weight: 60 parts desulfurized gypsum, 30 parts conversion furnace slag, and 10 parts papermaking white mud.

[0098] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0099] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 1000 r / min, and the ball milling time was 2 min;

[0100] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0101] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 2, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0102] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0103] Example 3

[0104] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0105] In the solid waste-based cementitious material, solid waste mixture A accounts for 90% by weight and solid waste mixture B accounts for 10% by weight.

[0106] Solid waste mixture A includes the following raw materials by weight: 30 parts Bayer red mud, 60 parts blast furnace slag, 5 parts steel slag, and 5 parts fly ash.

[0107] Solid waste mixture B includes the following raw materials in parts by weight: 30 parts phosphogypsum, 40 parts carbide slag, 10 parts papermaking mud, and 20 parts magnesium slag.

[0108] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0109] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 500 r / min, and the ball milling time was 10 min;

[0110] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0111] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 3, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0112] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0113] Example 4

[0114] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0115] In the solid waste-based cementitious material, solid waste mixture A accounts for 80% by weight and solid waste mixture B accounts for 20% by weight.

[0116] Solid waste mixture A includes the following raw materials by weight: 40 parts Bayer red mud, 10 parts fly ash, and 50 parts steel slag;

[0117] Solid waste mixture B comprises the following raw materials in parts by weight: 70 parts phosphogypsum and 30 parts carbide slag.

[0118] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0119] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 500 r / min, and the ball milling time was 10 min;

[0120] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0121] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 4, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0122] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0123] Example 5

[0124] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0125] In the solid waste-based cementitious material, solid waste mixture A accounts for 80% by weight and solid waste mixture B accounts for 20% by weight.

[0126] Solid waste mixture A includes the following raw materials by weight: 50 parts blast furnace slag, 30 parts fly ash, 10 parts fly ash, and 20 parts steel slag.

[0127] Solid waste mixture B includes the following raw materials in parts by weight: 50 parts phosphogypsum, 40 parts carbide slag, and 10 parts papermaking sludge.

[0128] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0129] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 500 r / min, and the ball milling time was 10 min;

[0130] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0131] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 5, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0132] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0133] Example 6

[0134] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0135] In the solid waste-based cementitious material, solid waste mixture A accounts for 80% by weight and solid waste mixture B accounts for 20% by weight.

[0136] Solid waste mixture A includes the following raw materials by weight: 70 parts fly ash, 20 parts fly ash, and 10 parts steel slag;

[0137] Solid waste mixture B includes the following raw materials in parts by weight: 20 parts phosphogypsum, 40 parts papermaking mud, and 40 parts magnesium slag.

[0138] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0139] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 500 r / min, and the ball milling time was 10 min;

[0140] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0141] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 6, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0142] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0143] Example 7

[0144] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0145] In the solid waste-based cementitious material, solid waste mixture A accounts for 75% by weight and solid waste mixture B accounts for 25% by weight.

[0146] Solid waste mixture A includes the following raw materials by weight: 60 parts fly ash, 20 parts blast furnace slag, 10 parts steel slag, and 10 parts fly ash.

[0147] Solid waste mixture B includes the following raw materials in parts by weight: 60 parts desulfurized gypsum, 20 parts conversion furnace slag, and 20 parts magnesium slag.

[0148] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0149] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 700 r / min, and the ball milling time was 5 min;

[0150] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0151] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 7, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days. The compressive strength and flexural strength of the mortar specimens are measured on the 7th day and the 28th day.

[0152] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0153] Example 8

[0154] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0155] In the solid waste-based cementitious material, solid waste mixture A accounts for 85% by weight and solid waste mixture B accounts for 15% by weight.

[0156] Solid waste mixture A includes the following raw materials by weight: 20 parts blast furnace slag, 60 parts steel slag, 10 parts Bayer red mud, and 10 parts fly ash.

[0157] Solid waste mixture B comprises the following raw materials in parts by weight: 30 parts desulfurized gypsum, 30 parts phosphogypsum, and 40 parts conversion furnace slag.

[0158] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0159] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 300 r / min, and the ball milling time was 50 min;

[0160] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0161] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 8, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0162] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0163] Example 9

[0164] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0165] In the solid waste-based cementitious material, solid waste mixture A accounts for 80% by weight and solid waste mixture B accounts for 20% by weight.

[0166] Solid waste mixture A includes the following raw materials by weight: 60 parts blast furnace slag, 20 parts fly ash, 10 parts steel slag, and 10 parts Bayer red mud.

[0167] Solid waste mixture B includes the following raw materials in parts by weight: 50 parts desulfurized gypsum and 50 parts carbide slag.

[0168] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0169] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 500 r / min, and the ball milling time was 10 min;

[0170] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0171] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 9, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0172] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0173] Example 10

[0174] This embodiment provides a solid waste-based cementitious material, comprising solid waste mixture A and solid waste mixture B;

[0175] In the solid waste-based cementitious material, solid waste mixture A accounts for 80% by weight and solid waste mixture B accounts for 20% by weight.

[0176] Solid waste mixture A includes the following raw materials by weight: 20 parts blast furnace slag, 20 parts Bayer red mud, 20 parts fly ash, 20 parts steel slag, and 20 parts fly ash.

[0177] Solid waste mixture B includes the following raw materials in parts by weight: 20 parts phosphogypsum, 20 parts desulfurization gypsum, 20 parts carbide slag, 20 parts papermaking white mud, 10 parts conversion furnace slag, and 10 parts magnesium slag.

[0178] The preparation method of the above-mentioned solid waste-based cementitious material includes the following steps:

[0179] Solid waste mixture A and solid waste mixture B were placed in a ball mill, milling media were added, and ball milling was carried out to obtain solid waste-based cementitious material; the ball mill speed was 500 r / min, and the ball milling time was 10 min;

[0180] During ball milling, the mass ratio of the ball milling media to the sum of the masses of solid waste mixture A and solid waste mixture B is 10:1; the ball milling media are zirconia balls.

[0181] This embodiment also provides a mortar material. The preparation method of the mortar material is as follows: the solid waste-based cementitious material prepared in Example 10, standard sand and water are mixed at a mass ratio of 1:3:0.5, and mortar specimens of 160 mm × 40 mm × 40 mm (i.e., length of 160 mm, width of 40 mm and height of 40 mm) are made. The mortar specimens are cured in a standard curing room at a curing temperature of 20°C and a relative humidity of 98%RH for 3 days, 7 days and 28 days. The compressive strength and flexural strength of the mortar specimens are measured.

[0182] The initial and final setting times of the cementitious materials were tested according to GB / T 1346-2024 (Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement). The seawater and sulfate attack resistance of the mortar specimens were tested according to GB / T 38140-2019 (Test Methods for Seawater Erosion Resistance of Cement) and GB / T 749-2008 (Test Methods for Sulfate Erosion Resistance of Cement). The test results are shown in Tables 1-3 below.

[0183] Table 1 - Compressive and flexural strengths of mortar specimens at 3d, 7d, and 28d, and initial and final setting times of cementitious materials in Examples 1-10.

[0184]

[0185] Table 2 - Corrosion resistance coefficients of sodium sulfate and magnesium sulfate for mortar specimens (cured for 28 days), 90 days, and 180 days in Examples 1-10.

[0186]

[0187] Table 3 - Retention rate of seawater erosion compressive strength of mortar specimens (cured for 28 days) in Examples 1-10 at 90 days and 180 days.

[0188]

[0189] Table 1 lists the mechanical properties and setting times of 10 solid waste-based cementitious material examples. Table 2 shows the erosion resistance data of the 10 solid waste-based cementitious material examples. Different solid waste component ratios significantly affect the overall performance of the materials. Among them, Examples 5 and 9 have the best overall performance, while Examples 4 and 6 have poor performance. The 3-day compressive strength of each example ranges from 12.7 to 35.1 MPa, the 3-day flexural strength ranges from 2.8 to 8.5 MPa, the 7-day compressive strength ranges from 18.6 to 42.7 MPa, the 7-day flexural strength ranges from 4.9 to 9.0 MPa, and the 28-day compressive strength ranges from 21.3 to 52.2 MPa, the 28-day flexural strength ranges from 2.5 to 11.6 MPa. Referring to GB 175-2023 "General Portland Cement" and related technical requirements for solid waste-based cementitious materials, the mechanical strength of 42.5R cement is a 3-day compressive strength of not less than 22.0 MPa and a flexural strength of ≥4.0 MPa. The 28-day compressive strength and flexural strength were not less than 2.5 MPa and 6.5 MPa, respectively. Except for Examples 4 (28-day compressive strength 21.3 MPa) and 6 (28-day compressive strength 29.6 MPa), the 28-day compressive strength of the other eight examples all met the strength requirements of grade 42.5 cement. Moreover, the 28-day compressive strengths of Examples 5 and 9 reached 52.2 MPa and 52.1 MPa, respectively, showing excellent mechanical properties. This is closely related to the fact that the solid waste mixture A in the two examples used blast furnace slag as the main component (50 parts and 60 parts, respectively). The activation of the blast furnace slag can effectively improve the strength development of the cementitious material. In terms of setting time, the initial setting time of each example ranged from 100 to 545 min, and the final setting time ranged from 390 to 1280 min, according to GB / T Standard GB / T 1346-2024, "Standard Consistency Water Requirement, Setting Time and Soundness of Cement," stipulates that the initial setting time of general-purpose Portland cement shall not be earlier than 45 min and the final setting time shall not be later than 600 min. The initial and final setting times of Examples 1-3, 5, 7, 9, and 10 all meet this standard requirement. However, the final setting times of Examples 4 (initial setting 545 min, final setting 1280 min), 6 (initial setting 395 min, final setting 995 min), and 8 (initial setting 380 min, final setting 710 min) exceed the standard limits. It is speculated that this is because the addition of a high proportion of steel slag and magnesium slag in the solid waste mixture slowed down the hydration reaction process. Regarding corrosion resistance, in both Na2SO4 and MgSO4 corrosive media, the 90-day corrosion resistance coefficient K1 of each example ranged from 0.95 to 1.33, and the 180-day corrosion resistance coefficient K2 ranged from 0.92 to 1.55, in accordance with GB / T According to GB / T 749-2008 "Test Method for Sulfate Resistance of Cement" and GB / T 38140-2019 "Test Method for Seawater Resistance of Cement", the corrosion resistance coefficient evaluation requirements are that a K value > 0.85 is considered as qualified corrosion resistance, except for Examples 4 (Na2SO4 medium K2=0.92) and 6 (Na2SO4 medium K2=1).04) Except for the weaker resistance to corrosion, the other examples all showed good resistance to sulfate corrosion. Examples 5 and 9 had K1 > 1.30 and K2 > 1.45, showing the best resistance to corrosion. In terms of strength retention rate in the seawater corrosion test, the 90-day compressive strength retention rate of each example was 86%~114%, and the 180-day compressive strength retention rate was 75%~127%. According to the requirements for long-term strength stability of solid waste-based cementitious materials in T / CECS 1943-2025 "Technical Specification for Application of Solid Waste-based Cementitious Materials in Concrete", a strength retention rate ≥ 85% is considered qualified. Example 4 (180-day retention rate of 75%) did not meet this requirement, while the other examples all met the standard. Among them, Example 9 had a 180-day strength retention rate of 127%, indicating its excellent long-term strength stability. The present invention is a composite cementitious material prepared by reasonable proportioning of various solid wastes and mechanical activation. Multiple embodiments exhibited a compressive strength retention rate >100% in seawater erosion tests and a corrosion resistance coefficient >1 in magnesium sulfate and sodium sulfate erosion tests, demonstrating excellent erosion resistance. The core mechanism is as follows: The mechanical activation effect of high-energy ball milling not only refines raw material particles and increases specific surface area but also breaks down the glassy and lattice structures in aluminosilicate solid waste, promoting solid-phase pre-reaction between raw materials, reducing the porosity of the hardened slurry, and physically hindering the diffusion of eroding ions. During the multi-component synergistic hydration process, solid waste mixture B not only provides a high-alkalinity environment to dissolve aluminosilicates and generate highly stable CASH gel but also provides Ca. 2+ SO4 2- It combines with aluminum to form ettringite, avoiding harmful expansion reactions and forming a dense matrix dominated by stable hydration products. Furthermore, it resists the corrosive ions (SO4) in seawater and sulfates. 2- Cl - Mg 2+ (etc.) It does not cause matrix degradation; instead, it undergoes a secondary hydration reaction with the residual active components in the system, and the resulting products fill the capillary pores, further improving the density and strength of the matrix. In the solid waste mixture A, the inert components in solid wastes such as red mud and slag act as a micro-aggregate skeleton, optimizing the volume stability of the system and inhibiting the propagation of microcracks during the erosion process. In summary, the synergistic effect of mechanical activation, multi-component synergistic hydration, secondary solidification by erosion ions, and regulation by inert components enables the material to exhibit excellent resistance to seawater and sulfate erosion.

[0190] Example 4 may have a low corrosion resistance coefficient because solid waste mixture A contains a high proportion of steel slag (50 parts) and solid waste mixture B contains only phosphogypsum and carbide slag, lacking components that effectively improve corrosion resistance. From the component ratio, component A is mainly composed of siliceous alumina solid waste such as blast furnace slag, fly ash, fly ash, steel slag, and Bayer process red mud, while component B is mainly composed of industrial by-product gypsum and slag such as phosphogypsum, desulfurization gypsum, and carbide slag. This conforms to the national standard plan (20250594-T-469) for "Regenerated Geopolymer Cementitious Materials from Silicate Alumina Solid Waste". The core requirement for the composition of the cementitious material is to use siliceous aluminate industrial solid waste as the main component and add industrial by-product gypsum and other materials as activators to realize the resource utilization of industrial solid waste. Among them, the reasonable proportion of components such as blast furnace slag and fly ash can effectively activate the activity of cementitious materials and improve mechanical properties and erosion resistance. However, an excessively high proportion of a single solid waste (such as 50 parts of steel slag in Example 4 and 70 parts of fly ash in Example 6) will lead to performance degradation. This indicates that the performance optimization of solid waste-based cementitious materials needs to rely on reasonable component matching to achieve the synergistic improvement of solid waste resource utilization and material performance.

[0191] Table 4 shows the leaching toxin results of the mortar specimens after 28 days of curing in Example 5, which were tested according to GB 5085.3–2007 (Identification Standard for Hazardous Waste: Leaching Toxicity Identification).

[0192] Table 4 - Leaching toxin results of mortar specimens cured for 28 days in Example 5

[0193]

[0194] In Table 4, ND indicates that the concentration of this element is less than 0.02 mg / L; Standard: GB 5085.3–2007 (Identification Standard for Hazardous Waste: Leaching Toxicity Identification)

[0195] The toxin leaching test results of the mortar specimens in Table 4 show that all detected heavy metal elements are below the legislative standard limits. Therefore, it can be concluded that the all-solid waste-based gel material does not pose a risk of heavy metal ion diffusion.

[0196] Figure 1 The XRD patterns are of the mortar specimens obtained after curing for 3 days, 7 days, and 28 days in Example 5.

[0197] from Figure 1 As can be seen, the main gel products after hydration of the cementitious material are CASH gel and AFt (ettringite). Figure 1Ettringite (CASH) and AFt are the core products in the hydration process of cementitious materials, and they synergistically regulate the development of material strength and durability. AFt, with its needle-like crystal structure, is rapidly generated in the early stages of hydration, constructing the initial spatial framework, providing early strength, regulating setting properties, and moderately compensating for shrinkage. The introduction of red mud is considered beneficial in promoting ettringite formation because it can provide more aluminum ions. CASH gel is generated in large quantities in the middle and late stages of hydration, achieving structural densification by encapsulating and binding aggregates and other hydration products, and filling pores. Furthermore, with the gradual extension of the curing period, the diffraction peaks of calcium carbonate were found to gradually increase, indicating that calcium carbonate is continuously generated in the system. The continuously generated calcium carbonate promotes microstructural densification and accelerates the hydration process through physical filling, chemical nucleation, reactive reactions, and interface optimization effects, synergistically improving the early and mid-to-late-stage strength and long-term durability of the material, and is an important driving factor for the performance optimization of cementitious materials.

[0198] Figure 2 The figures show the TG and DTG curves of the cementitious material obtained in Example 5 before and after mechanical activation, as well as the mortar specimen obtained after standard curing for 28 days in Example 5. "Unmechanically activated" refers to directly mixing solid waste mixture A and solid waste mixture B; "mechanically activated" refers to the cementitious material obtained by ball milling solid waste mixture A and solid waste mixture B in a ball mill according to the method in Example 5.

[0199] Figure 4 The images show SEM images of the mortar specimens obtained after 28 days of standard curing in Example 5, SEM images of the mortar specimens obtained after 28 days of standard curing immersed in seawater for 180 days, and SEM images of the mortar specimens obtained after 28 days of standard curing immersed in 5wt.% sodium sulfate (Na2SO4) solution and 5wt.% magnesium sulfate (MgSO4) solution for 180 days.

[0200] Figure 2 and Figure 3 The TG (thermogravimetric) curves and DTG (differential thermogravimetric) curves of the cementitious material before and after mechanical activation in Example 5, as well as the mortar specimens obtained after curing the mechanically activated cementitious material for 28 days, are shown. The thermal decomposition of the three samples can be roughly divided into three stages: Stage I (50-350℃), corresponding to the loss of bound water in the cementitious material and the dehydration of hydration products such as CASH and AFt; Stage II (350-500℃), attributed to the decomposition of Ca(OH)2; and Stage III (500-700℃), related to the decomposition of CaCO3.

[0201] from Figure 4As can be seen, obvious CASH gel and AFt were observed in the mortar specimens obtained after 28 days of standard curing in Example 5, which is consistent with the analysis results of the XRD pattern. The CASH gel and AFt are tightly interwoven, forming a dense structure, which is the reason why Example 5 has high mechanical strength. After immersing the mortar specimens obtained after 28 days of standard curing in seawater, 5 wt.% sodium sulfate solution, and 5 wt.% magnesium sulfate solution for 180 days, obvious CASH gel and AFt were still observed, and no obvious salt crystallization was observed. This indicates that the ions in the solution cannot penetrate into the gel and destroy various hydration products. This is related to the dense structure of the gel.

[0202] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0203] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A solid waste-based cementitious material, characterized in that, The following raw materials are included: solid waste mixture A and solid waste mixture B; The solid waste mixture A in the solid waste-based cementitious material has a weight percentage of 70-90%; The solid waste mixture A includes at least one of Bayer red mud, blast furnace slag, fly ash, steel slag, and fly ash. The solid waste mixture B includes at least one of papermaking sludge, carbide slag, conversion furnace slag, magnesium slag, desulfurization gypsum, and phosphogypsum.

2. The solid waste-based cementitious material as described in claim 1, characterized in that, The solid waste mixture A comprises the following raw materials in parts by weight: 0-45 parts Bayer red mud, 15-65 parts blast furnace slag, 0-35 parts fly ash, 0-55 parts steel slag, and 0-75 parts fly ash.

3. The solid waste-based cementitious material as described in claim 1, characterized in that, The solid waste mixture B comprises the following raw materials in parts by weight: 0-75 parts phosphogypsum, 0-65 parts desulfurization gypsum, 0-55 parts carbide slag, 0-45 parts papermaking sludge, 0-45 parts magnesium slag, and 0-45 parts conversion furnace slag.

4. The solid waste-based cementitious material as described in claim 2, characterized in that, The solid waste mixture A comprises the following raw materials in parts by weight: 50 parts blast furnace slag, 30 parts fly ash, 20 parts steel slag, and 10 parts fly ash; The solid waste mixture B comprises the following raw materials in parts by weight: 50 parts phosphogypsum, 40 parts carbide slag, and 10 parts papermaking sludge.

5. The solid waste-based cementitious material as described in claim 2, characterized in that, The solid waste mixture A comprises the following raw materials in parts by weight: 10 parts Bayer red mud, 60 parts blast furnace slag, 10 parts steel slag, and 20 parts fly ash; The solid waste mixture B comprises the following raw materials in parts by weight: 50 parts desulfurized gypsum and 50 parts carbide slag.

6. The solid waste-based cementitious material as described in claim 1, characterized in that, The Bayer process red mud comprises the following components by mass fraction: Fe2O3 30-40%, Al2O3 10-30%, SiO2 5-25%, CaO 2-10%, Na2O 2-10%, TiO2 0-5%; The blast furnace slag comprises the following components by mass fraction: Fe2O3 0~2.5%, Al2O3 10~20%, SiO2 30~45%, CaO 30~50%, MgO 3~10%; The fly ash comprises the following components by mass fraction: Fe2O3 3~15%, Al2O3 10~40%, SiO2 40~70%, CaO 2~10%; The steel slag comprises the following components by mass fraction: Fe2O3 10~30%, Al2O3 3~10%, SiO2 10~25%, CaO 40~60%, MnO 1~5%; The fly ash comprises the following components by mass fraction: Fe2O3 0~10%, Al2O3 25~45%, SiO2 40~60%, CaO 2~10%, K2O 1~5%, TiO2 0~5%; The papermaking sludge comprises the following components by mass fraction: CaCO3 85~90%, Ca(OH)2 4~5%, SiO2 3~7%, CaO 2-4%; The carbide slag comprises the following components by mass fraction: Ca(OH)2 78~90%, CaO 2~5%, CaCO3 5~10%, SiO2 1~8%; The conversion slag comprises the following components by mass fraction: CaO 40-60%, SiO2 10-20%, Fe2O3 20-30%, MgO 3-10%; The magnesium slag comprises the following components by mass fraction: CaO 45~55%, SiO2 25~35%, MgO 6~10%, Al2O3 2~5%, Fe2O3 3~9%, and CaF2 1~3%.

7. A method for preparing a solid waste-based cementitious material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Solid waste mixture A and solid waste mixture B are placed in a ball mill and ball-milled to obtain solid waste-based cementitious material.

8. The method for preparing solid waste-based cementitious materials as described in claim 7, characterized in that, The ball milling speed is 100~1000 r / min, and the ball milling time is 2~100 min.

9. The method for preparing the solid waste-based cementitious material as described in claim 7, characterized in that, During ball milling, the mass ratio of the sum of the masses of the ball milling media and solid waste mixture A to solid waste mixture B is (5~20):

1.

10. A mortar material, characterized in that, The preparation method of the mortar material is as follows: after mixing cementitious material, sand and water, the mixture is cured to obtain the mortar material. The cementing material is the solid waste-based cementing material according to any one of claims 1 to 6 or the solid waste-based cementing material prepared by the preparation method according to any one of claims 7 to 9.

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