A full-solid-waste geopolymer cementing material based on limestone, and a preparation method and application thereof

Abstract

The application discloses a kind of full solid waste geopolymer cementitious materials based on limestone and its preparation method and application, the raw material of the cementitious material includes first solid waste material, second solid waste material, alkali activator and modifier, modifier includes grinding aid, complexing agent and metal salt, the acid radical of metal salt is sulphate and / or nitrate;Wherein: first solid waste material includes limestone, second solid waste material includes at least contains Si-O-Al bond solid waste;When preparing, grinding aid is mixed with solid waste material and is mixed uniformly with remaining raw materials, and can be;Practice shows that the novel cementitious material of the application not only can effectively promote the dissolution of calcium carbonate and the fracture of Si-O-Al bond in solid waste component, form stable gel network, significantly improve the strength loss problem usually appeared after limestone (powder) incorporation, but also can realize the utilization of higher content limestone, be conducive to realizing the full solid waste utilization of raw material, also have the characteristics such as green low carbon in preparation process.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste utilization technology, specifically to a limestone-based all-solid waste geopolymer cementitious material, its preparation method, and its application. Background Technology

[0002] Sand and gravel aggregates are indispensable raw materials in engineering construction, but large-scale mining of sand and gravel aggregates also leads to a large amount of limestone powder emissions. Statistics show that for every ton of machine-made aggregate produced, approximately 0.1 to 0.3 tons of solid waste are generated, of which limestone powder accounts for 20% to 40%. The main component of limestone powder is calcite, with a stable mineral composition and virtually no cementitious properties. It is usually only used as a filler in cementitious materials in small quantities. To achieve efficient resource utilization of limestone powder, current research focuses primarily on its application as an admixture. However, research on the direct preparation of cementitious materials using limestone powder is still lacking, especially the technology for preparing geopolymers using limestone powder as the main raw material, which lacks mature or systematic publicly available schemes.

[0003] In terms of existing technology, patent CN102329105A proposes a method for preparing concrete using manganese slag-steel slag-limestone powder as an admixture. This method improves the durability of the concrete and reduces costs by approximately 20%. However, the limestone powder in this method needs to be ground to a particle size of 600-900 μm. 2 The specific surface area is only 5% to 10% of the limestone powder, and the utilization rate is low. The patent with publication number CN102659336 A proposes to use slag, calcined gypsum and triethanolamine to improve the low activity of limestone powder and obtain an admixture with higher activity. However, the amount of limestone powder used is also limited and it needs to be used together with a large amount of cement (about 60 wt.%) to obtain better mechanical properties. Patent CN 103910508 A discloses a limestone powder concrete design that uses 20%–40% blast furnace slag powder and 10%–30% limestone powder. The concrete produced using this method can achieve a C40 strength. However, the limestone powder needs to be ground to an average particle size of less than 10 μm, and the limestone powder does not react in the system, only acting as a filler.

[0004] Currently, in the field of limestone powder resource utilization, the common technical approach is to grind it into fine powder and add it as an admixture to cement-based systems, improving some properties through nucleation and filler effects. However, the improvement of the mechanical properties of cement-based materials by limestone powder is very limited, and high admixtures usually have negative effects; its dosage generally needs to be controlled below 30%. In summary, existing technologies lack effective methods to directly activate limestone powder and enable its internal CaCO3 to participate in reactions. Furthermore, the technology for preparing geopolymers using limestone powder as a calcium source is still lacking.

[0005] It should be noted that the information disclosed in the background section above is only for understanding the background of this application. Therefore, the background section of this invention may include background information about the problems or environment of this invention, and is not necessarily a description of the prior art. Thus, the content included in the background section does not constitute an admission of the prior art by the applicant. Summary of the Invention

[0006] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a new limestone-based all-solid waste geopolymer cementitious material.

[0007] The present invention also provides a method for preparing the above-mentioned limestone-based all-solid waste geopolymer cementitious material.

[0008] The present invention also provides an application of the above-mentioned limestone-based all-solid waste geopolymer cementitious material in civil engineering materials, electronic or mechanical devices.

[0009] To achieve the above objectives, the present invention employs the following technical solution: A limestone-based all-solid-waste geopolymer cementitious material, wherein the raw materials of the cementitious material include a first solid waste material, a second solid waste material, an alkali activator, and a modifier, wherein the modifier includes a grinding aid, a complexing agent, and a metal salt, and the acid anion of the metal salt is sulfate and / or nitrate; wherein: The first solid waste material contains limestone, and the second solid waste material contains solid waste containing at least Si-O-Al bonds. The total amount of the first solid waste material and the second solid waste material is in a mass ratio of 1:0.000001-0.004 to the grinding aid. The total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.002-0.15:0.0002-0.01:0.0005-0.02 to the amount of the alkaline activator, the complexing agent, and the metal salt.

[0010] In some embodiments of the present invention, the total amount of the first solid waste material and the second solid waste material is in a mass ratio of 1:0.0001-0.002 to the mass of the grinding aid.

[0011] In some embodiments of the present invention, the total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.004-0.14:0.0003-0.008:0.0008-0.01 to the mass of the alkaline activator, the complexing agent, and the metal salt.

[0012] Furthermore, the total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.005-0.12:0.0004-0.006:0.0009-0.006 to the amount of the alkali activator, the complexing agent, and the metal salt.

[0013] Furthermore, the total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.005-0.05:0.0006-0.003:0.0009-0.004 to the mass of the alkaline activator, the complexing agent, and the metal salt.

[0014] In some embodiments of the present invention, the mass ratio of the first solid waste material to the second solid waste material is 0.2-5:1. Further, the mass ratio of the first solid waste material to the second solid waste material is 0.2-3:1.

[0015] In some embodiments of the present invention, the second solid waste material further includes solid waste containing calcium sulfate.

[0016] According to some specific aspects of the present invention, the second solid waste material comprises at least one of blast furnace slag powder, steel slag powder, and waste brick powder, and optionally includes desulfurized gypsum powder and / or fluorogypsum powder.

[0017] In some embodiments of the present invention, the limestone is in powder form.

[0018] In some embodiments of the present invention, the limestone has a specific surface area of ​​180~500 m². 2 / g of limestone powder.

[0019] In some embodiments of the present invention, the second solid waste material is powdered solid waste.

[0020] In some embodiments of the present invention, the second solid waste material has a specific surface area of ​​180~500 m². 2 / g of solid waste powder.

[0021] In some embodiments of the present invention, the second solid waste material is composed of blast furnace slag powder, steel slag powder, desulfurized gypsum powder and / or fluorogypsum powder, wherein the mass ratio of the blast furnace slag powder, the steel slag powder, the desulfurized gypsum powder and / or fluorogypsum powder is 1:0.4-0.8:0.20-0.42; or, the second solid waste material is composed of blast furnace slag powder and waste brick powder, wherein the mass ratio of the blast furnace slag powder to the waste brick powder is 1:0.5-2.0; or, the second solid waste material is composed of blast furnace slag powder and steel slag powder, wherein the mass ratio of the blast furnace slag powder to the steel slag powder is 1:0.4-0.6.

[0022] In some embodiments of the present invention, the grinding aid is a substance that is alkaline in aqueous solution and can chelate with metal ions.

[0023] According to some specific aspects of the invention, the grinding aid comprises one or more combinations selected from sodium citrate, sodium tripolyphosphate, diethanolmonoisopropanolamine, and sodium salicylate.

[0024] In some embodiments of the present invention, the grinding aid is diethanol monoisopropanolamine, or is composed of diethanol monoisopropanolamine and sodium citrate in a mass ratio of 0.05-0.3:1, or is composed of sodium tripolyphosphate and sodium salicylate in a mass ratio of 0.5-2.0:1, or is composed of diethanol monoisopropanolamine and sodium salicylate in a mass ratio of 0.05-0.3:1.

[0025] In some embodiments of the present invention, the complexing agent is a water-soluble polymeric compound with a molecular chain rich in polar complexing groups, wherein the polar complexing groups comprise one or more combinations of carboxyl groups, amide bonds, primary amino groups, secondary amino groups, and pyrrolidone rings.

[0026] According to some specific aspects of the invention, the complexing agent comprises one or more combinations selected from polyaspartic acid, polyethyleneimine, and polyvinylpyrrolidone.

[0027] In some embodiments of the present invention, the metal salt comprises one or more combinations selected from barium nitrate, zinc sulfate, and sodium sulfate.

[0028] In some embodiments of the present invention, the alkali activator comprises one or more combinations selected from sodium silicate, sodium hydroxide, cement clinker, quicklime, and sodium aluminate.

[0029] Another technical solution provided by the present invention: a method for preparing the above-mentioned limestone-based all-solid waste geopolymer cementitious material, the preparation method comprising: The first solid waste material and the second solid waste material are mixed evenly, then a grinding aid is added, and the mixture is ground to produce a pre-treated powder. Add the remaining raw materials to the pretreated powder and mix thoroughly.

[0030] In some embodiments of the present invention, the specific surface area of ​​the pretreated powder is 300-600 m². 2 / g.

[0031] Another technical solution provided by the present invention is the application of the above-mentioned limestone-based all-solid waste geopolymer cementitious material in civil engineering materials, electronic or mechanical devices.

[0032] Civil engineering materials include building materials for houses, roads, bridges, tunnels, and ground / wall decorations. For example, they are used in the manufacture or auxiliary manufacture of corresponding materials or structural components in fields such as building components, walls, structures, roads, roadbeds, floors, mine filling, tunnel support, soil and rock reinforcement, fire-resistant and heat-resistant materials, canal seepage prevention, water-saving components, and reservoirs.

[0033] Electronic or mechanical devices include the packaging and manufacturing of electronic components or mechanical devices, or auxiliary manufacturing, such as as gel encapsulation, insulating fixation, or as a structural layer of materials such as glass or fiber, or as structural adhesives, sealants, etc.

[0034] Another technical solution provided by the present invention: a mortar, the mortar comprising the above-mentioned limestone-based all-solid waste geopolymer cementitious material, water and quartz sand.

[0035] According to some preferred aspects of the present invention, the curing conditions of the mortar are: curing temperature of 10-80℃ and relative humidity of 50%-100%.

[0036] In some embodiments of the present invention, the curing conditions of the mortar are: curing temperature of 30-80℃ and relative humidity of 60%-90%.

[0037] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: Addressing the current limitations in limestone powder resource utilization, such as insufficient limestone utilization rate, inability to fully utilize the calcium carbonate content, and limited improvement in material mechanical properties, this invention innovatively provides a novel limestone-based all-solid-waste polymer cementitious material. This material, by combining a first solid-waste material containing limestone and a second solid-waste material containing at least Si-O-Al bonds, along with grinding aids, complexing agents, and metal salts of specific acid radicals, effectively promotes the dissolution of calcium carbonate and the breaking of Si-O-Al bonds in the solid-waste components in the presence of an alkaline activator. This results in a stable C(N)-ASH gel network, with the resulting polymer structure exhibiting an amorphous or quasi-crystalline three-dimensional network. This significantly improves the strength loss problem commonly encountered after limestone (powder) incorporation, and allows for high-content utilization, facilitating the complete solid-waste utilization of raw materials. The preparation process is green and low-carbon, and the resulting material possesses high strength, excellent flowability, and good durability.

[0038] The novel limestone-based all-solid waste geopolymer cementitious material of this invention has the advantages of high strength, stable structure, controllable performance, large limestone powder consumption capacity, easy operation, low production cost, and low carbon and environmental protection. Attached Figure Description

[0039] Figure 1 The above are statistical charts of the compressive strength of Examples 1-5 and Comparative Examples 1-5 of the present invention; Figure 2 The above are statistical charts of the flexural strength of Examples 1-5 and Comparative Examples 1-5 of the present invention. Figure 3 The XRD pattern of Comparative Example 1 (A: tricalcium silicate; La: clinoptilolite; C: calcite; Gy: calcium sulfate; Po: calcium hydroxide); Figure 4 The XRD patterns of Examples 1-2 are shown (C: calcite; Gy: calcium sulfate; Mc: single-carbon hydrated calcium aluminate). Figure 5 The DSC curves for the slurries of Examples 1-2 and Comparative Example 1 are shown. Figure 6 The TG curves for the slurries of Examples 1-2 and Comparative Example 1 are shown. Figure 7 The pore size distribution diagrams are shown for the slurries of Examples 1-2 and Comparative Example 1 at 3 days of hydration age. Figure 8 This is a statistical chart of the cumulative pore volume of the slurry at 3 days of hydration age for Examples 1-2 and Comparative Example 1; Figure 9 The microstructure of the slurry in Example 2 (CaCO3: calcium carbonate; CASH: calcium aluminum silicate hydration gel; Ett: calcium vanadate; m-Mc: modified single-carbon hydrated calcium aluminate carbohydrate). Figure 10 The microstructure of the slurry in Comparative Example 1 (CaCO3: calcium carbonate; CSH: calcium silicate hydration gel). Detailed Implementation

[0040] Limestone powder's main component is calcite, which typically does not exhibit pozzolanic activity or potential hydration activity in cement-based systems, and excessive addition can negatively impact the system's strength development. However, limestone powder has a high calcium content, and if it can be used as a calcium source in the geopolymer preparation process, it can be effectively utilized. Furthermore, the resulting semi-carbon / single-carbon calcium aluminate can effectively improve the bonding strength of the geopolymer network, fill harmful pores, and thus prepare geopolymer materials with high mechanical properties. This invention promotes the dissolution of calcite in limestone powder and its participation in the system's reaction process. Simultaneously, it uses alkali activators, grinding aids, complexing agents, and other modifiers to promote calcium ion dissolution, thereby accelerating the breaking of silicon-aluminum bonds and the formation and structural evolution of C(N)-ASH gel, thus accelerating the early strength development of the system.

[0041] Based on this, the present invention provides a limestone-based all-solid-waste geopolymer cementitious material. The raw materials of the cementitious material include a first solid waste material, a second solid waste material, an alkali activator, and a modifier. The modifier includes a grinding aid, a complexing agent, and a metal salt, wherein the acid anion of the metal salt is sulfate and / or nitrate. Wherein: The first solid waste material contains limestone, and the second solid waste material contains solid waste containing at least Si-O-Al bonds. The total amount of the first solid waste material and the second solid waste material is in a mass ratio of 1:0.000001-0.004 to the grinding aid. The total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.002-0.15:0.0002-0.01:0.0005-0.02 to the amount of the alkaline activator, the complexing agent, and the metal salt.

[0042] In this invention, the main raw materials used include limestone (powder), blast furnace slag powder, steel slag powder, and fluorogypsum. Limestone (powder) serves as the primary solid waste material, while the other solid waste materials are secondary solid waste materials containing at least Si-O-Al bonds. The main component of limestone (powder) is calcite, which itself lacks significant hydration activity, and its incorporation into cement systems typically leads to a decrease in system strength. Industrial solid wastes such as blast furnace slag powder, steel slag powder, and fluorogypsum are also difficult to use directly in building material preparation. This invention achieves efficient utilization of solid waste by rationally designing the combination of various solid wastes to ensure that calcium, silicon, and aluminum in the system reach suitable geopolymer reaction conditions. Furthermore, this invention utilizes the synergistic effect of grinding aids and alkali activators to jointly stimulate the potential activity of various mineral phases in the limestone powder-based solid waste powder, and the entire process does not involve a calcination step, effectively reducing preparation costs and energy consumption.

[0043] This invention pertains to limestone-based geopolymer systems, whose polymerization products include CASH gel, CSH gel, and NASH gel, exhibiting an amorphous or quasi-crystalline three-dimensional framework structure. This polymeric network endows the system with excellent flexural strength and overall mechanical properties at the microscopic level. Geopolymers prepared using various industrial solid wastes are not only low-cost and have a high resource utilization rate, but also, due to the effective participation of calcium sources in limestone powder, provide sufficient reactive components for the formation of the three-dimensional polymeric network, resulting in geopolymers exhibiting excellent strength and durability.

[0044] This invention utilizes the synergistic effect of grinding aids and alkali activators to promote the dissolution of calcium carbonate in limestone powder and the breaking of Si-O-Al bonds in solid waste powder, thereby achieving effective control over the polymerization reaction. While calcium carbonate itself has limited solubility, it can partially dissolve in locally highly alkaline environments or under chelation conditions, releasing Ca2+. 2+ Promotes C(N)-ASH gel formation. Complexing agents that are water-soluble and have molecular chains rich in polar complexing groups possess multidentate complexing capabilities; examples include polyaspartic acid, polyethyleneimine, and polyvinylpyrrolidone. 2+ The dissolution-promoting efficiency is higher, and it is also higher in high Ca... 2+ and high SO4 2- The system makes the size of calcium vanadate more uniform and is conducive to the continuous formation of gel network; some complexing agents (such as polyvinylpyrrolidone) have strong surface adsorption of blast furnace slag powder and can change the gel deposition mode, transforming it from flocculent to continuous film, further improving the continuity of the interface transition zone and microstructure.

[0045] This invention employs a rapid curing process that significantly promotes the dissolution of Si and Al components, accelerates the ability of the alkali activator to break the Si-O-Al bonds in the raw materials, increases the dissolution rate of each component, and enables the glass phase to transform into Q more quickly. 0 Q 1It contains silicate and aluminate monomers with similar structures. Simultaneously, increasing the temperature can further promote the condensation reaction of the silica-alumina components, accelerating the formation of NASH or NCASH gels, which is beneficial for forming a continuous and dense three-dimensional network structure.

[0046] In summary, this invention uses limestone (powder) as the main raw material, in conjunction with various industrial solid wastes such as blast furnace slag powder and steel slag powder, to construct a limestone-based polymer system based on solid waste. Through scientifically designed combinations of calcium, silicon, and aluminum, and utilizing the synergistic activation effect of grinding aids and alkali activators, the dissolution of calcium carbonate and the breaking of Si-O-Al bonds in the solid waste components are effectively promoted, forming a stable C(N)-ASH gel network. The resulting polymer structure exhibits an amorphous or quasi-crystalline three-dimensional network, significantly improving the strength loss problem commonly encountered after the incorporation of limestone powder. The addition of grinding aids improves powder activity and slurry flowability; the complexing agent promotes the polymerization of Ca in calcite. 2+ The release rate of the polymer provides raw materials for the polymerization reaction and the formation of calcium vanadate, and improves the continuity of the polymer network; specific metal salts can improve the fluidity of the geopolymer slurry and slow down its setting time; rapid curing can accelerate the dissolution and condensation of silicon-aluminum components, making the geopolymer structure more compact. This invention realizes the complete solid waste utilization of raw materials, the preparation process is green and low-carbon, and the obtained material has high strength, excellent fluidity and good durability, with significant engineering application value and sustainable development significance.

[0047] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0048] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0049] Example 1: This example provides a limestone-based all-solid waste polymer cementitious material and its preparation method. The preparation method includes: weighing 40 parts by weight of limestone powder, 30 parts by weight of blast furnace slag powder, 20 parts by weight of steel slag powder, and 10 parts by weight of fluorogypsum powder, and uniformly mixing them to obtain a mixed powder raw material. 0.02 parts by weight of the grinding aid diethanol monoisopropanolamine are weighed and added to 100 parts by weight of the mixed powder raw material, and then ground to obtain a specific surface area of ​​578 m². 2 / g of pretreated powder. The pretreated powder, sodium hydroxide, polyaspartic acid, and zinc sulfate were mixed in a mass ratio of 100:0.5:0.1:0.3 to obtain a limestone-based all-solid-waste geopolymer cementitious material. According to standard GB / T 17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded into mortar. The mortar was then cured in an environment of 30℃ and 90% relative humidity for 3 days to obtain limestone-based all-solid-waste geopolymer mortar, denoted as S1.

[0050] Example 2: This example provides a limestone-based all-solid waste polymer cementitious material and its preparation method. The preparation method includes: weighing 40 parts by weight of limestone powder, 35 parts by weight of blast furnace slag powder, 15 parts by weight of steel slag powder, and 10 parts by weight of desulfurized gypsum powder, and uniformly mixing them to obtain a mixed powder raw material. Weighing 0.01 parts by weight of diethanol monoisopropanolamine and 0.1 parts by weight of sodium citrate, adding them to 100 parts by weight of the mixed powder raw material, and grinding to obtain a specific surface area of ​​544 m². 2 / g of pretreated powder. The pretreated powder, sodium silicate, sodium hydroxide, polyaspartic acid, and zinc sulfate were mixed in a mass ratio of 100:6:1:0.2:0.2 to obtain a limestone-based all-solid-waste geopolymer cementitious material. According to standard GB / T 17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded to obtain mortar. The mortar was then cured in an environment of 50℃ and 60% relative humidity for 3 days to obtain limestone-based all-solid-waste geopolymer mortar, denoted as S2.

[0051] Example 3: This example provides a limestone-based all-solid waste polymer cementitious material and its preparation method. The preparation method includes: weighing 40 parts by weight of limestone powder, 32 parts by weight of blast furnace slag powder, 15 parts by weight of steel slag powder, and 13 parts by weight of desulfurized gypsum powder, and uniformly mixing them to obtain a mixed powder raw material. Weighing 0.02 parts by weight of diethanol monoisopropanolamine, adding it to 100 parts by weight of the mixed powder raw material, and grinding it to a specific surface area of ​​480 m² 2 / g of pretreated powder. The pretreated powder, sodium aluminate, polyvinylpyrrolidone, and barium nitrate were mixed in a mass ratio of 100:2:0.1:0.2 to obtain a limestone-based all-solid-waste geopolymer cementitious material. According to standard GB / T 17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded to obtain mortar. The mortar was then cured in an environment of 30℃ and 90% relative humidity for 3 days to obtain limestone-based all-solid-waste geopolymer mortar, denoted as S3.

[0052] Example 4: This example provides a limestone-based all-solid waste polymer cementitious material and its preparation method. The preparation method includes: weighing 40 parts by weight of limestone powder, 30 parts by weight of blast furnace slag powder, and 30 parts by weight of waste brick powder, and uniformly mixing them to obtain a mixed powder raw material. Weighing 0.1 parts by weight of sodium tripolyphosphate and 0.1 parts by weight of sodium salicylate, adding them to 100 parts by weight of the mixed powder raw material, and grinding to a specific surface area of ​​498 m². 2 / g of pretreated powder. The pretreated powder, sodium silicate, sodium hydroxide, polyethyleneimine, and barium nitrate were mixed in a mass ratio of 100:9:3:0.04:0.3 to obtain a limestone-based all-solid-waste geopolymer cementitious material. According to standard GB / T 17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded to obtain mortar. The mortar was then cured in an environment of 50℃ and 60% relative humidity for 3 days to obtain limestone-based all-solid-waste geopolymer mortar, denoted as S4.

[0053] Example 5: This example provides a limestone-based all-solid waste polymer cementitious material and its preparation method. The preparation method includes: weighing 70 parts by weight of limestone powder, 18 parts by weight of blast furnace slag powder, 8 parts by weight of steel slag powder, and 4 parts by weight of desulfurized gypsum powder, and uniformly mixing them to obtain a mixed powder raw material. Weighing 0.01 parts by weight of diethanolmonoisopropanolamine and 0.1 parts by weight of sodium salicylate, adding them to 100 parts by weight of the mixed powder raw material, and grinding to obtain a specific surface area of ​​505 m². 2 / g of pretreated powder. The pretreated powder, sodium aluminate, polyaspartic acid, and zinc sulfate were mixed in a mass ratio of 100:5:0.2:0.2 to obtain a limestone-based all-solid-waste geopolymer cementitious material. According to standard GB / T17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded to obtain mortar. The mortar was then cured in an environment of 50℃ and 60% relative humidity for 3 days to obtain limestone-based all-solid-waste geopolymer mortar, denoted as S5.

[0054] Example 6: This example provides a limestone-based all-solid waste polymer cementitious material and its preparation method. The preparation method includes: weighing 70 parts by weight of limestone powder, 20 parts by weight of blast furnace slag powder, and 10 parts by weight of steel slag powder, and mixing them evenly to obtain a mixed powder raw material. Weighing 0.02 parts by weight of diethanol monoisopropanolamine, adding it to 100 parts by weight of the mixed powder raw material, and grinding it to a specific surface area of ​​539 m². 2 / g of pretreated powder. The pretreated powder, sodium silicate, sodium hydroxide, polyaspartic acid, and zinc sulfate were mixed in a mass ratio of 100:5:2:0.5:0.1 to obtain a limestone-based all-solid-waste geopolymer cementitious material. According to standard GB / T 17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded to obtain mortar. The mortar was then cured in an environment of 80℃ and 50% relative humidity for 3 days to obtain limestone-based all-solid-waste geopolymer mortar.

[0055] Comparative Example 1: A cement-based cementitious material containing limestone powder is prepared as follows: 40 parts by weight of limestone powder and 60 parts by weight of P.I 42.5 cement are weighed and mixed evenly to obtain the cement-based cementitious material containing limestone powder. According to standard GB / T 17671-2021, the limestone powder-containing cement-based cementitious material is mixed with water and standard sand and molded to obtain mortar. The mortar is cured in an environment with a temperature of 30℃ and a relative humidity of 100% for 3 days to obtain the limestone powder-containing cement-based mortar, denoted as R1.

[0056] Comparative Example 2: A limestone-free, all-solid-waste-based polymer cementitious material is prepared as follows: 50 parts by weight of blast furnace slag powder, 33 parts by weight of steel slag powder, and 17 parts by weight of fluorogypsum powder are weighed, mixed evenly, and then ground to obtain 503 m³ of the cementitious material. 2 / g specific surface area pretreated powder. These components were mixed at a mass ratio of 100:0.5 of pretreated powder and sodium silicate to obtain a limestone-free geopolymer cementitious material. According to standard GB / T 17671-2021, the limestone-free geopolymer cementitious material was mixed with water and standard sand and molded into mortar. The mortar was then cured in an environment with a temperature of 30℃ and a relative humidity of 90% for 3 days to obtain a limestone-free all-solid-waste geopolymer mortar, denoted as R2.

[0057] Comparative Example 3: A limestone-free, all-solid-waste polymer cementitious material is prepared as follows: 50 parts by weight of blast furnace slag powder and 50 parts by weight of waste brick powder are weighed, mixed evenly, and then ground to obtain a 480 m³ / h mass. 2 / g specific surface area of ​​the pretreated powder. The pretreated powder, sodium silicate, and sodium hydroxide were mixed in a mass ratio of 100:9:3 to obtain a limestone-free, all-solid-waste geopolymer cementitious material. According to standard GB / T 17671-2021, the limestone-free geopolymer cementitious material was mixed with water and standard sand and molded into mortar. The mortar was then cured in an environment of 50℃ and 60% relative humidity for 3 days to obtain limestone-free, all-solid-waste geopolymer mortar, denoted as R3.

[0058] Comparative Example 4: A limestone-based solid waste polymer cementitious material without complexing agents and its preparation method are basically the same as in Example 3, except that no complexing agent is added. Specifically, the preparation method includes: weighing 40 parts by weight of limestone powder, 32 parts by weight of blast furnace slag powder, 15 parts by weight of steel slag powder, and 13 parts by weight of desulfurized gypsum powder, and mixing them evenly to obtain a mixed powder raw material. Weighing 0.02 parts by weight of diethanol monoisopropanolamine, adding it to 100 parts by weight of the mixed powder raw material, and grinding it to a specific surface area of ​​492 m². 2 / g of pretreated powder. The pretreated powder, sodium aluminate, and barium nitrate were mixed in a mass ratio of 100:2:0.2 to obtain a limestone-based solid waste geopolymer cementitious material without complexing agents. According to standard GB / T 17671-2021, the geopolymer cementitious material was mixed with water and standard sand and molded into mortar. The mortar was then cured in an environment of 30℃ and 90% relative humidity for 3 days to obtain limestone powder-based solid waste geopolymer mortar, denoted as R4.

[0059] Comparative Example 5: A cement-based cementitious material containing limestone powder is prepared as follows: 70 parts by weight of limestone powder and 30 parts by weight of P.I 42.5 cement are weighed and mixed evenly to obtain the cement-based cementitious material containing limestone powder. According to standard GB / T 17671-2021, the limestone powder-containing cement-based cementitious material is mixed with water and standard sand and molded into mortar. The mortar is then cured in an environment with a temperature of 30℃ and a relative humidity of 100% for 3 days to obtain the limestone powder-containing cement-based mortar, denoted as R5.

[0060] Performance testing: According to GB / T 17671-2021 "Test Method for Strength of Cement Mortar", the mechanical properties of the mortars obtained by molding using Examples 1-5 and Comparative Examples 1-5 were tested. Their 3-day, 7-day, and 28-day compressive and flexural strengths are as follows: Figures 1-2 As shown in Table 1, the setting times of the cement pastes in Examples 1-5 and Comparative Examples 1-5 were determined according to GB / T 1346-2024 "Test Methods for Standard Consistency Water Requirement, Setting Time and Soundness of Cement". The mineral phase analysis of the hydration / polymerization products of the geopolymer paste and the cement paste containing stone powder at 3 days and 7 days was performed using XRD, and the results are shown below. Figures 3-4 As shown. TG / DSC analysis was used to determine the degree of reaction of limestone powder in different systems. Thermal analysis results of the slurries formed using Examples 1-2 and Comparative Example 1 are shown below. Figures 5-6 As shown, its pore size distribution and cumulative pore volume are as follows: Figures 7-8 As shown.

[0061] like Figures 1-2 As shown, the incorporation of inert limestone powder into the cement system significantly weakens strength development. When 40 wt.% limestone powder was added, the 28-day compressive strength of P·Ⅰ 42.5 cement mortar was 32.17 MPa (Comparative Example 1). Using the same amount of limestone powder, by adjusting the high-alumina component (blast furnace slag powder), alkali activator (sodium silicate and sodium hydroxide), and sulfur activator (desulfurized gypsum), the 28-day compressive strength of the limestone powder solid waste-based polymer mortar reached 44.10 MPa (Example 3), an increase of 36.96% compared to the cement mortar containing 40 wt.% limestone powder. Compared to the solid waste-based polymer mortar without limestone powder (Comparative Example 2), the 28-day strength of Example 2 increased by 22.51%. Without the addition of a complexing agent, the 3-day strength of Comparative Example 4 reached 14.12 MPa, similar to Example 3. However, when the curing age reached 28 days, the compressive strength of Example 3 was 18.20% higher than that of Comparative Example 4. This is because the complexing agent promotes the growth of Ca in the limestone powder. 2+ The continuous filtration of limestone continuously provides raw materials for the formation of CASH and CSH gel networks, thereby enhancing the strength of the system. Meanwhile, both Example 5 and Comparative Example 5 used high limestone content. Although the initial strength was lower, compared to Comparative Example 5, the strength of Example 5 increased faster and more significantly with increasing curing time.

[0062] As shown in Table 1, the initial setting time and final setting time of Example 4 were extended by 61 min and 79 min respectively compared to Comparative Example 2, meeting the setting time requirements for engineering applications. This indicates that the overall system of the present invention can improve and regulate the setting process, and its effect may be related to the reduced reaction rate of aluminum phase and sulfate ions in the system.

[0063] Table 1. Setting times of Examples 1-5 and Comparative Examples 1-5 Combination Figures 3-4 Mineral phase analysis of R1 showed that calcite diffraction peaks were high in the limestone powder-cement system, and no single-carbon hydrated calcium aluminate (Mc) formation was detected. This indicates that limestone powder only acts as a filler in the cement system, and high admixture significantly reduces the system strength. Comparing Examples 1 and 2, it was observed that calcite reacts with the aluminum phase dissolved from the slag to form Mc, thereby significantly improving the early and later strength of the system, especially at 7 days. Adjusting the composition of the alkali activator further enhanced the dissociation of the aluminum phase, resulting in a higher compressive strength in Example 2 than in Example 1.

[0064] from Figures 5-6The thermal analysis results show that the limestone powder-cement system exhibits a significant endothermic peak and mass loss at approximately 450℃, corresponding to the dehydration and decomposition reaction of Ca(OH)2 produced during cement hydration. This characteristic is absent in the limestone-based polymer system. Furthermore, the limestone powder-based polymer shows an even more significant endothermic peak and mass loss in the 100–200℃ range, mainly related to the decomposition of Mc.

[0065] Depend on Figures 7-8 Analysis of the pore structure shows that in the limestone-based geopolymer slurry of this invention, due to the formation of the polymer network, a large number of micropores with a diameter <20 nm appear, and their volume is approximately 400% of that of the limestone powder-cement slurry. Simultaneously, the content of capillary pores in the 50-200 nm range is significantly reduced. This phenomenon indicates that a large number of harmless micropores are formed in the geopolymer system, while harmful capillary pores are significantly reduced, thereby significantly improving the macroscopic mechanical properties. Furthermore, the reduction of harmful pores also contributes to improving the durability of the material. Figures 9-10 The secondary electron microscopy analysis shown indicates that a large amount of CASH gel was generated in the limestone-based polymer slurry of this invention (Example 2). Furthermore, due to the participation of calcium carbonate crystals in the formation of modified monocarbonate hydrated calcium aluminate, fewer calcium carbonate particles were observable in the slurry. In contrast, a large number of loosely packed calcium carbonate particles were observed in the limestone powder-cement slurry (Comparative Example 1), and these particles were bonded together by cement hydration products. This phenomenon indirectly reflects the low reactivity of limestone powder in the cement system, and the accumulation of inert calcium carbonate particles reduces the macroscopic strength of the slurry.

[0066] As used throughout the specification and claims, the term "comprising" is an open-ended term and should be interpreted as "comprising but not limited to." "Substantially" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the product or system comprising said element.

[0067] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0068] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A limestone-based all-solid waste polymer cementitious material, characterized in that, The raw materials of the gelling material include a first solid waste material, a second solid waste material, an alkali activator, and a modifier. The modifier includes a grinding aid, a complexing agent, and a metal salt, wherein the acid anion of the metal salt is sulfate and / or nitrate. The first solid waste material contains limestone, and the second solid waste material contains solid waste containing at least Si-O-Al bonds. The total amount of the first solid waste material and the second solid waste material is in a mass ratio of 1:0.000001-0.004 to the grinding aid. The total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.002-0.15:0.0002-0.01:0.0005-0.02 to the amount of the alkaline activator, the complexing agent, and the metal salt.

2. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The total amount of the first solid waste material and the second solid waste material, in mass ratio to the grinding aid, is 1:0.0001-0.002; and / or, The total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.004-0.14:0.0003-0.008:0.0008-0.01 to the feed content of the alkali activator, the complexing agent, and the metal salt; and / or, The mass ratio of the first solid waste material to the second solid waste material is 0.2-5:

1.

3. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The mass ratio of the first solid waste material to the second solid waste material is 0.2-3:1; and / or, The total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.005-0.12:0.0004-0.006:0.0009-0.006 to the amount of the alkaline activator, the complexing agent, and the metal salt.

4. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The second solid waste material also includes solid waste containing calcium sulfate; and / or, The limestone used has a specific surface area of ​​180~500 m². 2 / g of limestone powder; and / or, The second solid waste material has a specific surface area of ​​180~500 m². 2 / g of solid waste powder; and / or, The total amount of the first solid waste material, the second solid waste material, and the grinding aid is in a mass ratio of 1:0.005-0.05:0.0006-0.003:0.0009-0.004 to the mass of the alkaline activator, the complexing agent, and the metal salt.

5. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The second solid waste material comprises at least one of blast furnace slag powder, steel slag powder, and waste brick powder, and optionally includes desulfurized gypsum powder and / or fluorogypsum powder; and / or, The grinding aid is a substance that is alkaline in aqueous solution and can chelate with metal ions.

6. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The grinding aid comprises one or more combinations selected from sodium citrate, sodium tripolyphosphate, diethanolmonoisopropanolamine, and sodium salicylate; and / or, The complexing agent is a water-soluble polymer compound with a molecular chain rich in polar complexing groups, wherein the polar complexing groups include one or more combinations of carboxyl groups, amide bonds, primary amino groups, secondary amino groups, and pyrrolidone rings.

7. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The complexing agent comprises one or more combinations selected from polyaspartic acid, polyethyleneimine, and polyvinylpyrrolidone; and / or, The metal salt comprises one or more combinations selected from barium nitrate, zinc sulfate, and sodium sulfate; and / or, The alkali activator comprises one or more combinations selected from sodium silicate, sodium hydroxide, cement clinker, quicklime, and sodium aluminate.

8. The limestone-based all-solid waste polymer cementitious material according to claim 1, characterized in that, The second solid waste material is composed of blast furnace slag powder, steel slag powder, desulfurized gypsum powder, and / or fluorogypsum powder, wherein the mass ratio of the blast furnace slag powder, steel slag powder, desulfurized gypsum powder, and / or fluorogypsum powder is 1:0.4-0.8:0.20-0.42; or, the second solid waste material is composed of blast furnace slag powder and waste brick powder, wherein the mass ratio of the blast furnace slag powder to the waste brick powder is 1:0.5-2.0; or, the second solid waste material is composed of blast furnace slag powder and steel slag powder, wherein the mass ratio of the blast furnace slag powder to the steel slag powder is 1:0.4-0.

6. And / or, The grinding aid is diethanol monoisopropanolamine, or it can be composed of diethanol monoisopropanolamine and sodium citrate in a mass ratio of 0.05-0.3:1, or it can be composed of sodium tripolyphosphate and sodium salicylate in a mass ratio of 0.5-2.0:1, or it can be composed of diethanol monoisopropanolamine and sodium salicylate in a mass ratio of 0.05-0.3:

1.

9. A method for preparing a limestone-based all-solid waste polymer cementitious material according to any one of claims 1-8, characterized in that, The preparation method includes: The first solid waste material and the second solid waste material are mixed evenly, then a grinding aid is added, and the mixture is ground to produce a pre-treated powder. Add the remaining raw materials to the pretreated powder and mix thoroughly.

10. The preparation method according to claim 9, characterized in that, The specific surface area of ​​the pretreated powder is 300-600 m². 2 / g.

11. The application of a limestone-based all-solid waste geopolymer cementitious material as described in any one of claims 1-8 in civil engineering materials, electronic or mechanical devices.

12. A mortar, characterized in that, The mortar comprises the limestone-based all-solid waste geopolymer cementitious material as described in any one of claims 1-8, water, and quartz sand.

13. The mortar according to claim 12, characterized in that, The curing conditions for the mortar are: curing temperature of 10-80℃ and relative humidity of 50%-100%.

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