Preparation method of activated lithium slag and ternary copolymer gel material thereof

Abstract

The application discloses a kind of activated lithium slag and preparation method of ternary copolymer cementitious material thereof, belong to building material technical field.Preparation method of ternary copolymer cementitious material of the application, including the following steps: after mixing and wet grinding fly ash and carbide slag, C-A-S-H crystal nucleus is obtained;After ball milling, high-temperature calcination and mixing with alkali activator, C-A-S-H crystal nucleus is added, and activated lithium slag is obtained;Activated lithium slag, magnesium slag, slag and water are mixed uniformly, and after pouring and curing, ternary copolymer cementitious material is obtained.The activated lithium slag, magnesium slag, slag of the application have synergistic effect, and the three form "silicon aluminum dissolution-ion migration-gel crystallization" continuous reaction chain through alkali excitation, accelerate C-(A)-S-H gel and ettringite formation, significantly promote early hardening of geopolymer, improve mechanical strength, structural density and durability.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a method for preparing activated lithium slag and its terpolymer cementitious material. Background Technology

[0002] Cement-based materials are the most widely used man-made building materials in the world, with a history of nearly two centuries. However, the cement production process is a high-CO2 emission process, accounting for approximately 5-8% of global CO2 emissions. Geopolymers, as a low-carbon alternative to cement, form a three-dimensional network structure through alkali-activated aluminosilicate precursors, exhibiting significant low-carbon and environmentally friendly advantages as well as excellent performance, attracting considerable attention in the building materials field. Compared to traditional cement, geopolymers significantly reduce energy consumption during production, lowering CO2 emissions by approximately 80%, while also efficiently utilizing industrial solid waste, aligning with global sustainable development principles. However, geopolymers prepared from single precursors often have performance limitations, such as insufficient early strength in slag-based geopolymers.

[0003] Therefore, researchers have attempted to combine raw materials with different properties to achieve synergistic effects and improve the overall performance of materials. Rawat et al. prepared geopolymers by compounding slag and fly ash, finding that slag provides early strength, while fly ash promotes later strength growth. A reasonable ratio of the two can give geopolymers good mechanical properties at different ages, but requires the use of a high amount of alkali activator, which can lead to increased matrix porosity, resulting in decreased mechanical strength and significant degradation of durability. Luo et al. studied a metakaolin-slag-fly ash ternary system, finding that this system can improve the microstructure of geopolymers, enhance density, and improve compressive strength and impermeability. However, the addition of metakaolin reduces the fluidity of geopolymer concrete. Therefore, there is an urgent need to find geopolymers that combine both strength and durability to replace cement, a man-made building material. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing activated lithium slag and its terpolymer cementitious material, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of the present invention: a method for preparing activated lithium slag, comprising the following steps: CASH crystal nuclei are obtained by wet grinding a mixture of fly ash and carbide slag. The lithium slag is successively ball-milled and calcined at high temperature, then mixed with an alkaline activator (for alkaline activation), and the CASH crystal nuclei are added to obtain the activated lithium slag.

[0006] Preferably, the grinding media used in the wet grinding includes zirconia balls with a diameter of 5 to 20 mm; The molar ratio of Ca to Si in the CASH crystal nucleus is 1.8:1; The wet milling speed is 100 rpm and the time is 8 hours.

[0007] When the Ca content in the system is too high, excessive Ca will disrupt the normal polymerization process of Si-O-Al and Si-O-Si bonds, and will produce an excessively rapid early reaction, greatly shortening the setting time and inducing microcracks on the surface of the microstructure, resulting in weakened slurry adhesion. When the Ca content in the system is too low, the microstructure will exhibit a porous and loose gel state, accompanied by a large number of unreacted fly ash particles and pores; the alkalinity cannot be effectively increased to accelerate the dissolution of fly ash particles, resulting in a limited reaction rate, which will also ultimately lead to insufficient microstructure density and low overall compressive strength of the material.

[0008] Preferably, the grinding media consists of 5mm zirconia balls, 10mm zirconia balls, 15mm zirconia balls, and 20mm zirconia balls in a mass ratio of 1:1:1.5:2. The total mass ratio of fly ash and carbide slag to the mass ratio of zirconium oxide balls is 1:6.

[0009] Preferably, the amount of CASH crystal nucleus used is 1 wt.% of the lithium slag mass. The ball mill has a ball-to-material ratio of 6:1, a rotation speed of 100 rpm, and a time of 2 hours. The high-temperature calcination was carried out at 700℃ for 2 hours. The amount of the alkaline activator is 10 wt.% of the lithium slag mass.

[0010] CASH nuclei can provide heterogeneous nucleation sites to accelerate cement hydration reactions, significantly improving the early strength and durability of cementitious materials.

[0011] When lithium slag is activated by physical ball milling, the median particle size of the lithium slag decreases with increasing milling time, which can increase the specific surface area of ​​the lithium slag (the specific surface area of ​​lithium slag is 1.2303 m²). 2 / g, the specific surface area of ​​the activated lithium slag is 2.0775m². 2 / g).

[0012] High-temperature calcination can increase the content of amorphous active phase in lithium slag from 30 wt.% to 50 wt.%, which can significantly enhance the intensity of the exothermic peak, make the hydration reaction more intense and the degree of reaction higher, thereby generating more hydration gel products, making the material structure more compact, and improving the compressive strength of the material.

[0013] Alkali activators can effectively enhance the pozzolanic activity of lithium slag, thereby accelerating the breakage of silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons and releasing active monomers. These monomers rapidly undergo condensation reactions in solution to generate a large number of hydration products such as C-(A)-SH gel, which improves compressive strength.

[0014] Using only physical ball milling can only increase the amorphous phase content in lithium slag to 34-38%; using only high-temperature calcination risks damaging the structural integrity of the material, resulting in the geopolymer failing to develop strength. This invention, however, utilizes a multi-process synergistic activation involving the addition of CASH nuclei, ball milling, high-temperature calcination, and alkali activation to increase the amorphous active phase content to 50 wt.%, thereby improving the material's compressive strength.

[0015] The second technical solution of the present invention: an activated lithium slag prepared by the above preparation method.

[0016] The third technical solution of the present invention: a ternary copolymer cementitious material, comprising the above-mentioned activated lithium slag, magnesium slag and ore slag.

[0017] Preferably, the terpolymer cementitious material comprises, by mass percentage, the following raw materials: 5-20% activated lithium slag, 5-20% magnesium slag, and 80-90% slag.

[0018] Preferably, the water-cement ratio of the terpolymer gelling material is 0.4.

[0019] Fourth technical solution of the present invention: A method for preparing the above-mentioned terpolymer gelling material, comprising the following steps: The activated lithium slag, magnesium slag, mineral slag and water are mixed evenly, poured and cured to obtain the ternary copolymer cementitious material.

[0020] Fifth technical solution of the present invention: an application of the above-mentioned terpolymer cementitious material as a building material.

[0021] The present invention discloses the following technical effects: (1) The present invention significantly improves the activity of lithium slag by synergistic activation through multiple processes such as adding CASH crystal nuclei, ball milling, high-temperature calcination and alkali activation. The pore size distribution of the activated lithium slag is more concentrated in the smaller pore size range, the peak value of pore volume change rate is significantly higher than that before activation, and the specific surface area is increased, effectively solving the problem of limited activity improvement by a single activation method.

[0022] (2) The activated lithium slag, magnesium slag and slag of the present invention have a synergistic effect. The activated lithium slag provides a highly active silicon-aluminum source, the magnesium slag introduces MgO to stimulate the depolymerization of the slag glass, and the slag, as the main cementitious matrix, provides a calcium source. The three form a continuous reaction chain of "silicon-aluminum dissolution-ion migration-gel crystallization" through alkali activation, which accelerates the formation of C-(A)-SH gel and ettringite, significantly promotes the early hardening of the geopolymer, and improves the mechanical strength, structural density and durability.

[0023] The optimal ratio for preparing ternary geopolymer cementitious materials from activated lithium slag, magnesium slag, and mineral slag is A10M10G80. This ratio increases the 7-day compressive strength by 137.9% compared to the control group, indicating that the ternary system can effectively compensate for the performance shortcomings of a single precursor.

[0024] (3) The method of the present invention provides a practical and feasible technical path for the high-value utilization of lithium slag, and at the same time provides theoretical support for the development and application of industrial solid waste-based low-carbon cementitious materials, thus contributing to the green and sustainable development of the building materials industry. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0026] Figure 1 This is a microscopic morphology diagram of the lithium slag (LS) used in this invention; Figure 2 This is a microscopic morphology diagram of the magnesium slag (MS) used in this invention; Figure 3 This is a microscopic morphology diagram of the carbide slag (CS) used in this invention; Figure 4 This is a microscopic morphology diagram of the slag (GGBFS) used in this invention; Figure 5 The pore size distribution curves are for the lithium slag (LS) used in this invention and the activated lithium slag (ALS) prepared in Example 1. Figure 6 The mixing ratio of the geopolymer cementitious material of the present invention; Figure 7 SEM image of the CASH crystal nucleus prepared in Example 1 of this invention; Figure 8 The XRD pattern of the CASH crystal nucleus prepared in Example 1 of this invention; Figure 9 The compressive strength of the geopolymer cementitious materials prepared in Examples 2-13 of this invention after 7 days of curing; Figure 10 The compressive strength of the geopolymer cementitious materials prepared in Examples 2-13 of this invention after 28 days of curing; Figure 11 Fourier transform infrared spectra of A10M10G80 prepared in Example 4, A15M5G80 prepared in Example 5, A5G95 prepared in Example 12, and G100 prepared in Example 13 of this invention. Figure 12 XRD patterns of A10M10G80 prepared in Example 4, A15M5G80 prepared in Example 5, A10G90 prepared in Example 11, A5G95 prepared in Example 12, and G100 prepared in Example 13 of the present invention; Figure 13 The image shows a SEM image of G100 prepared in Example 13 of this invention. Figure 14 The image shown is an SEM image of A5G95 prepared in Example 12 of this invention. Figure 15 This is a SEM image of A10M10G80 prepared in Example 4 of the present invention; Figure 16 The image shows the SEM image of A15M5G80 prepared in Example 5 of this invention. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0033] In the following examples, "parts" refers to "parts by weight".

[0034] In the specific embodiments of this invention, the lithium slag (LS) used is produced in Yichun City, Jiangxi Province, China, and is lithium slag powder obtained after crushing and sieving; the fly ash (FA) is first-grade fly ash produced in Zhengzhou City, Henan Province, China; the calcium carbide slag (CS) comes from Longze Water Purification Materials Co., Ltd. in Gongyi City; the magnesium slag (MS) comes from a magnesium smelter; the blast furnace slag (GGBFS) comes from S95 grade blast furnace slag produced in Zhengzhou City, Henan Province; and the test sand and test water are national standard sand and purified water.

[0035] The microstructure of lithium slag (LS) is shown in the figure below. Figure 1 The microstructure of magnesium slag (MS) is shown in the figure. Figure 2 Microscopic morphology images of carbide slag (CS) are shown below. Figure 3 Microscopic morphology images of slag (GGBFS) are shown below. Figure 4 .

[0036] Samples of lithium slag, magnesium slag (median particle size 46.46 μm), blast furnace slag (median particle size 7.504 μm), fly ash (median particle size 32.66 μm), and carbide slag (median particle size 23.15 μm) used in the experiment were taken and semi-quantitatively analyzed by X-ray fluorescence spectroscopy (XRF). The test results are shown in Table 1.

[0037] Table 1 Chemical composition of raw materials Example 1 A method for preparing activated lithium slag: (1) Mix fly ash and carbide slag, control the molar ratio of Ca to Si to be 1.8:1, add deionized water with a total mass of 2 times that of fly ash and carbide slag, mix evenly, add zirconia balls with a total mass of 6 times that of fly ash and carbide slag (composed of 5mm zirconia balls, 10mm zirconia balls, 15mm zirconia balls and 20mm zirconia balls with a mass ratio of 1:1:1.5:2), put them in a polyethylene ball milling jar, wet mill at 100 rpm for 8 hours at room temperature, and then dry to obtain CASH crystal nuclei; Zirconia balls with a diameter of 5 mm were added to the lithium slag, and the ball-to-material ratio was controlled at 6:1. The mixture was ball-milled at 100 rpm for 2 hours and then calcined at 700℃ for 2 hours. After calcination, 10 wt.% NaOH (by weight of lithium slag) was added, and finally 1 wt.% CASH crystal nuclei (by weight of lithium slag) were added and mixed evenly to obtain activated lithium slag (ALS).

[0038] The particle size distribution characteristics of lithium slag (LS) and activated lithium slag (ALS) were determined by the BRT test method. The results are shown in [Figure number missing]. Figure 5 .

[0039] from Figure 5 As can be seen, the pore size distribution curves of both lithium slag (LS) and activated lithium slag (ALS) show a trend of first rising and then falling, indicating that there is a peak in the pore volume change rate within a specific pore size range. Comparison reveals that the peak pore volume change rate of activated lithium slag (ALS) corresponds to a smaller pore size, and the peak value is significantly higher than that of unactivated lithium slag (LS). This indicates that activation promotes the formation of more smaller pores in the lithium slag, with a significant increase in either the number or volume. Furthermore, the ALS curve drops sharply after reaching its peak, while the LS curve drops relatively gently, indicating that the smaller pore size distribution is more concentrated in the activated lithium slag, while the pore size distribution is more dispersed before activation. Within the smaller pore size range (e.g., 2–10 nm), the pore volume change rate of ALS rises rapidly and reaches its peak, while the increase in LS is slower, indicating that activation promotes the development of small-pore size pores.

[0040] The mix proportions of geopolymer cementitious materials are shown in the figure. Figure 6 ( Figure 6 In the figure, MS represents magnesium slag, ALS represents lithium slag, and GGBFS represents mineral slag. An example of preparing geopolymer cementitious materials using the proportions shown in the figure is as follows: Example 2 Preparation method of M20G80 geopolymer cementitious material: 20 parts magnesium slag and 80 parts slag were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled at 0.4. The mixture was first stirred slowly for 1 minute, and then stirred rapidly for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain M20G80 geopolymer cementitious material.

[0041] Example 3 Preparation method of A5M15G80 ternary geopolymer cementitious material: Five parts of activated lithium slag, 15 parts of magnesium slag, and 80 parts of slag prepared in Example 1 were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled at 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain A5M15G80 ternary geopolymer cementitious material.

[0042] Example 4 Preparation method of A10M10G80 ternary geopolymer cementitious material: Ten parts of activated lithium slag, ten parts of magnesium slag, and eighty parts of slag prepared in Example 1 were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled to be 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20 mm × 20 mm × 20 mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20 ± 2℃, relative humidity ≥ 95%) for 7 to 28 days to obtain A10M10G80 ternary geopolymer cementitious material.

[0043] Example 5 Preparation method of A15M5G80 ternary geopolymer cementitious material: 15 parts of activated lithium slag, 5 parts of magnesium slag, and 80 parts of slag prepared in Example 1 were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled to be 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain A15M5G80 ternary geopolymer cementitious material.

[0044] Example 6 Preparation method of A20G80 geopolymer cementitious material: 20 parts of activated lithium slag prepared in Example 1 and 80 parts of slag were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled to be 0.4. The mixture was first stirred slowly for 1 minute, and then stirred rapidly for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain A20G80 geopolymer cementitious material.

[0045] Example 7 Preparation method of A5M10G85 ternary geopolymer cementitious material: Five parts of activated lithium slag, 10 parts of magnesium slag, and 85 parts of slag prepared in Example 1 were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled at 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain A5M10G85 ternary geopolymer cementitious material.

[0046] Example 8 Preparation method of A10M5G85 ternary geopolymer cementitious material: Ten parts of activated lithium slag, five parts of magnesium slag, and eighty-five parts of slag prepared in Example 1 were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled at 0.4. The mixture was first stirred slowly for 1 minute, and then stirred rapidly for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20 mm × 20 mm × 20 mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20 ± 2℃, relative humidity ≥ 95%) for 7 to 28 days to obtain A10M5G85 ternary geopolymer cementitious material.

[0047] Example 9 Preparation method of M10G90 geopolymer cementitious material: 10 parts magnesium slag and 90 parts slag were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled at 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to make a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain M10G90 geopolymer cementitious material.

[0048] Example 10 Preparation method of A5M5G90 ternary geopolymer cementitious material: Five parts of activated lithium slag, five parts of magnesium slag, and ninety parts of slag prepared in Example 1 were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled to be 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain A5M5G90 ternary geopolymer cementitious material.

[0049] Example 11 Preparation method of A10G90 geopolymer cementitious material: Ten parts of activated lithium slag prepared in Example 1 and 90 parts of slag were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled to be 0.4. The mixture was first stirred slowly for 1 minute and then stirred rapidly for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20 mm × 20 mm × 20 mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20 ± 2℃, relative humidity ≥ 95%) for 7 to 28 days to obtain A10G90 geopolymer cementitious material.

[0050] Example 12 Preparation method of A5G95 geopolymer cementitious material: Five parts of activated lithium slag prepared in Example 1 and 95 parts of slag were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled to be 0.4. The mixture was first slowly stirred for 1 minute, and then quickly stirred for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20 mm × 20 mm × 20 mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20 ± 2℃, relative humidity ≥ 95%) for 7 to 28 days to obtain A5G95 geopolymer cementitious material.

[0051] Example 13 Preparation method of G100 geopolymer cementitious material: 100 parts of slag were poured into a mixer and mixed thoroughly. Water was added to the mixture, and the water-cement ratio was controlled at 0.4. The mixture was first stirred slowly for 1 minute, and then stirred rapidly for 1 minute to form a uniform slurry. The slurry was poured into a steel mold with dimensions of 20mm×20mm×20mm and poured in three layers. Each layer was tamped and vibrated multiple times to facilitate the expulsion of air bubbles. After curing at room temperature for 1 day, the sample was demolded and placed in a standard curing chamber (20±2℃, relative humidity ≥95%) for 7~28 days to obtain G100 geopolymer cementitious material.

[0052] Example 1 The CASH crystal nuclei prepared in Example 1 were observed by scanning electron microscopy (SEM), and the results are shown in the figure. Figure 7 The diffraction peak distribution and intensity of the CASH crystal nuclei prepared in Example 1 were measured using X-ray diffraction (XRD). The phase composition was analyzed using PDF cards. The results are shown in [Figure 1]. Figure 8 .

[0053] from Figure 7As can be seen, CASH crystal nuclei exhibit a complex and irregular microstructure, with a structure resembling interwoven and stacked sheets or foils. The overall structure presents a loose and porous state. This unique microstructure affects its specific surface area, porosity, and other properties, thereby influencing its performance in related material systems.

[0054] from Figure 8 As can be seen from the data, the main phase of the CASH crystal nucleus is C-(A)-SH gel, with a small amount of Ca(OH)2 and CaCO3 diffraction peaks present, indicating that the main cementitious phase of the crystal nucleus is significantly formed. Although it contains trace amounts of byproducts, it still possesses good cementitious performance potential. In cement-based materials, CASH crystal nuclei can promote hydration, optimize the microstructure, and thus improve the key properties of the material, such as mechanical strength and durability.

[0055] Example 2 Compressive strength test: The compressive strength was measured using a fully automatic compression-flexural strength testing machine (YAW-300C) at a constant loading rate of 2.4 kN / s ± 0.2 kN / s. The average value of three groups of specimens (geopolymer cementitious materials prepared in Examples 2-13) after curing for 7 days and 28 days was taken as the final compressive strength. The results are shown in the figure. Figure 9 (7 days of maintenance) and Figure 10 (Cure for 28 days).

[0056] from Figure 9 and Figure 10 As can be seen, at 7 days, the compressive strength of geopolymer specimens with different ratios of activated lithium slag-magnesium slag-slag exhibited significant differences. This is because the three raw materials—activated lithium slag, magnesium slag, and slag—have different activities, resulting in differences in the degree of early reaction. Taking the G100 group (prepared in Example 13) as an example, its early strength was low, only 15.3 MPa. This is because it only contains slag, and the activity activation is insufficient, making it difficult to quickly form a large amount of hydration products that contribute to strength. In contrast, the A10M10G80 group (prepared in Example 4) achieved a 7-day compressive strength of 36.4 MPa, an increase of 137.9% compared to the G100 group. This indicates that the added activated lithium slag and magnesium slag can produce a synergistic effect with the slag, effectively activating the activity of the system and thus promoting the hydration reaction. As the curing period extends to 28 days, the reaction within the geopolymer cementitious material system continues to deepen, the hydration reaction progresses, and more hydration products are generated. These products gradually fill the pores within the system, making the microstructure of the geopolymer increasingly dense and further enhancing its strength.

[0057] The performance of geopolymer cementitious materials containing an appropriate amount of activated lithium slag shows that the active components in the activated lithium slag can accelerate the depolymerization process of the slag glass. After depolymerization, the internal ions are released, making the ion exchange and recombination process more complete, thereby generating more hydration products and improving the compressive strength of the geopolymer. However, when the ratio of activated lithium slag, magnesium slag, and slag is unbalanced, there may be too many impurities in the system. Excessive impurities will occupy the reaction space, interfere with the normal hydration reaction, and hinder the development of geopolymer strength. Therefore, precise control of the ratio of activated lithium slag, magnesium slag, and slag is crucial for optimizing the compressive strength of geopolymers.

[0058] Example 3 Fourier transform infrared spectroscopy (FT-IR): Fourier transform infrared spectroscopy (FT-IR) was used to analyze the chemical bonds and functional groups of geopolymer cementitious materials (A10M10G80 prepared in Example 4, A15M5G80 prepared in Example 5, A5G95 prepared in Example 12, and G100 prepared in Example 13). Combined with relevant database analysis, the reaction mechanism of the geopolymers was analyzed (revealing the chemical bonding characteristics and structural evolution of the hydration products). The results are shown in [Figure number missing]. Figure 11 .

[0059] from Figure 11 As can be seen, five distinct peaks were clearly identified using Fourier transform infrared spectroscopy (FT-IR), with the peak at 3455 cm⁻¹. -1 The nearby absorption peak belongs to the stretching vibration of -OH, at 1640 cm⁻¹. -1 The nearby absorption peaks belong to the bending vibrations of -OH groups, indicating the presence of interlayer water between strong hydrogen bonds, primarily originating from the CASH gel. In the silicon-oxygen tetrahedral vibration region, at 965 cm⁻¹... -1 The nearby absorption peak is attributed to the antisymmetric stretching vibration of the Si-O-Si bond, 484 cm⁻¹. -1 The nearby absorption peaks are due to out-of-plane and in-plane bending vibrations of the Si-O bonds, primarily originating from the CASH gel. (1487 cm⁻¹) -1The nearby absorption peaks are due to the stretching vibrations of CO bonds, mainly originating from calcite. Comparing different samples, the characteristic peak intensity and peak shape of pure slag sample G100 can be used as a reference for the degree of silica-oxygen polymerization of pure slag. Compared with G100, the intensity of the -OH peak in samples containing activated lithium slag and magnesium slag (A15M5G80, A10M10G80, A5G95) changes, indicating that the introduction of activated lithium slag and magnesium slag alters the degree of hydration or moisture distribution of the system. The intensity and peak position of Si-O and CO-related peaks also differ, indicating that after the incorporation of activated lithium slag and magnesium slag, its silicon, aluminum and other components participate in the geopolymerization reaction, interact with the slag components, promote the depolymerization and repolymerization of aluminosilicates, and form a more complex geopolymer network structure.

[0060] Example of effect 4 Phase analysis (XRD): X-ray diffraction (XRD) analysis was performed on five groups of geopolymers: A10M10G80 prepared in Example 4, A15M5G80 prepared in Example 5, A10G90 prepared in Example 11, A5G95 prepared in Example 12, and G100 prepared in Example 13. The results are shown in the figure. Figure 12 .

[0061] from Figure 12 As can be seen, the G100 group has a relatively simple phase composition, with weak C-(A)-SH gel diffraction peaks and a lack of synergy with other phases, making it difficult to form an effective strength-supporting structure, resulting in poor overall material strength, which is consistent with the compressive strength test results. The A5G95 group introduced a small amount of activated lithium slag, which enhanced the SiO2 diffraction peaks, but the overall change was limited, the reactivity within the system was still insufficient, the amount of C-(A)-SH gel formed was insufficient, and the strength development was limited. The A10G90 group further increased the proportion of activated lithium slag, which enhanced the diffraction peaks related to SiO2 and CaSO4·2H2O, indicating an improved excitation effect. Early reactions are accelerated, but the formation of AFt and C-(A)-SH gel is relatively insufficient, resulting in limited strength growth and insufficient improvement in structural density. Although the A15M5G80 group has increased activated lithium slag, the phase ratio is not well coordinated, and the increased AFt peak intensity may lead to excessive early expansion, affecting structural stability. The A10M10G80 group achieves the best balance of phases, with an appropriate amount of AFt forming, providing stable strength growth in the early stage without causing expansion and damage due to excessive AFt. The large amount of C-(A)-SH gel forms, fully filling the pores and constructing a continuous and robust network structure, significantly improving strength. SiO2 and forsterite (Mg2SiO4) exist stably, reasonably dispersing stress and enhancing structural stability.

[0062] Example 5 Scanning electron microscopy (SEM) analysis The G100 prepared in Example 13 was analyzed by scanning electron microscopy (SEM), and the results are shown in the figure. Figure 13 The A5G95 prepared in Example 12 was analyzed by scanning electron microscopy (SEM), and the results are shown in the figure. Figure 14 The A10M10G80 prepared in Example 4 was analyzed by scanning electron microscopy (SEM), and the results are shown in the figure. Figure 15 The A15M5G80 prepared in Example 5 was analyzed by scanning electron microscopy (SEM), and the results are shown in the figure. Figure 16 .

[0063] from Figure 13 As can be seen, the slag particles in group G100 exhibit a smooth glassy surface. Under high magnification, only needle-like ettringite and thin-film Ca(OH)2 are visible. There are a large number of irregular pores (pore size 1-5 μm) between the particles. This structure originates from the high degree of polymerization of silicon-aluminum bonds (Si-O-Si / Al) in the glassy slag. Under alkaline excitation, the depolymerization is insufficient, and the amount of hydration products generated is insufficient, so a continuous cementitious network cannot be formed. Combined with the low crystallinity SiO2 diffraction peaks in the XRD pattern of the slag, it is further confirmed that its activity release is limited.

[0064] from Figure 14 As can be seen, a thin layer of flocculent CSH gel adheres to the surface of the slag in group A5G95. The edges of the lithium slag particles are blurred due to alkali erosion, but the gel coverage is discontinuous, with 2-5 μm cracks between particles, forming an island-like structure of "slag-gel-lithium slag". This phenomenon indicates that the silicon and aluminum ions released by 5% active lithium slag only weakly promote slag hydration, and the amount of silicon and aluminum dissolved is limited, failing to overcome the bottleneck of single activation.

[0065] from Figure 15 As can be seen, the slag, lithium slag, and magnesium slag particles in group A10M10G80 are completely encapsulated by clustered CASH gel, forming a dense network with a pore size of less than 0.5μm. The gel is in the form of "cauliflower-like" aggregates (size 5-10μm), with needle-like AFt (length 1-2μm) interspersed inside, forming a "gel-crystal interlocking" structure.

[0066] from Figure 16 As can be seen, the addition of activated lithium slag and magnesium slag in group A15M5G80 resulted in the formation of a partially network-like gel, which played a certain role in strength formation. However, some lithium slag did not react completely, exhibiting "island-like" agglomeration with a clearly visible porous structure on the surface. Plate-like crystals larger than 5 μm (presumably Ca(OH)2) appeared in the gel, increasing porosity and disrupting structural uniformity. Excessive lithium slag consumed the alkali activator, leading to the Ca... 2+ The insufficiency and lack of complete reaction of silicon and aluminum ions confirm the inhibitory effect of alkaline dilution on hydration.

[0067] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing activated lithium slag, characterized in that, Includes the following steps: CASH crystal nuclei are obtained by wet grinding a mixture of fly ash and carbide slag. The lithium slag is ball-milled and calcined at high temperature, then mixed with an alkaline activator, and the CASH crystal nuclei are added to obtain the activated lithium slag.

2. The preparation method according to claim 1, characterized in that, The grinding media used in the wet grinding include zirconia balls with a diameter of 5 to 20 mm; And / or, the molar ratio of Ca to Si in the CASH crystal nucleus is 1.8:1; And / or, the wet milling speed is 100 rpm and the time is 8 hours.

3. The preparation method according to claim 1, characterized in that, The grinding media consists of 5mm zirconia balls, 10mm zirconia balls, 15mm zirconia balls and 20mm zirconia balls in a mass ratio of 1:1:1.5:2; And / or, the total mass ratio of the fly ash and carbide slag to the mass ratio of the zirconia balls is 1:

6.

4. The preparation method according to claim 1, characterized in that, The amount of CASH crystal nuclei used is 1 wt.% of the lithium slag mass. And / or, the ball mill has a ball-to-material ratio of 6:1, a rotation speed of 100 rpm, and a time of 2 hours; And / or, the high-temperature calcination temperature is 700°C and the time is 2 hours; And / or, the amount of the alkaline activator is 10 wt.% of the lithium slag mass.

5. An activated lithium slag prepared by the preparation method according to any one of claims 1 to 4.

6. A terpolymer cementitious material, characterized in that, It includes the activated lithium slag, magnesium slag, and mineral slag as described in claim 5.

7. The terpolymer cementitious material according to claim 6, characterized in that, By mass percentage, it includes the following raw materials: 5-20% activated lithium slag, 5-20% magnesium slag, and 80-90% slag.

8. The terpolymer cementitious material according to claim 6, characterized in that, The water-cement ratio of the terpolymer gelling material is 0.

4.

9. A method for preparing the terpolymer cementitious material according to any one of claims 6 to 8, characterized in that, Includes the following steps: The activated lithium slag, magnesium slag, mineral slag and water are mixed evenly, poured and cured to obtain the ternary copolymer cementitious material.

10. The application of the terpolymer cementitious material according to any one of claims 6 to 8 as a building material.

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