Lithium slag-based geopolymer based on rice hull ash nano-modified material and preparation method of lithium slag-based geopolymer

Abstract

The invention discloses a lithium slag-based geopolymer based on a rice hull ash nano-modified material and a preparation method of the lithium slag-based geopolymer. The geopolymer comprises the rice hull ash nano-modified material and a powder component, the rice hull ash nano-modified material is prepared by the following steps: mixing rice hull ash, alkali liquor and nano silicon dioxide, adding water, and reacting at 150-250 DEG C for 4-6 hours, so as to obtain the rice hull ash nano-modified material. On the basis of a rice hull ash modified material, the geopolymer can be coagulated within 120-200 min, the coagulation time is shortened by 35%, the coagulation time is shortened, the 7d compressive strength can still reach 25Mpa or above, and the 28d compressive strength can still reach 40Mpa or above. In addition, the strength of the geopolymer prepared in each batch is stable and has no obvious fluctuation, and the batch stability of industrial production preparation is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium slag geopolymer, and particularly relates to a lithium slag geopolymer based on rice husk ash nano-modified material and a preparation method thereof. BACKGROUND

[0002] Geopolymer is an inorganic material mainly composed of silicate and aluminate, which has the characteristics of low carbon, high temperature resistance and excellent mechanical properties, and is expected to replace traditional cement. It is usually prepared by alkali activation of industrial solid waste (such as fly ash and slag) to form a three-dimensional network structure, but has defects such as low early strength, high brittleness and obvious shrinkage, which restricts its engineering application.

[0003] In recent years, lithium slag (lithium salt by-product containing active silicon and aluminum) and mineral powder (such as blast furnace slag) have become research hotspots, but the residual alkaline substances and low active components in lithium slag can easily lead to low reaction efficiency and high porosity, and the non-uniformity of mineral powder particles affects the homogeneity of the material. Therefore, researchers introduce nano materials (such as nano SiO2) for modification, but the cost is high and the compatibility with the matrix is insufficient.

[0004] Rice husk ash is a potential economic auxiliary cementitious material. Its raw material, rice, is one of the most important food crops in the world, with a huge production capacity. According to statistics, the global rice production in 2020 was about 757 million tons, and 1 kg of rice will produce about 0.28 kg of rice husk. After burning, 20-25% of rice husk ash will be produced. The SiO2 content in rice husk ash is very high and difficult to degrade naturally, and random disposal can cause potential harm to the environment. Therefore, using rice husk ash in building materials can significantly increase its added value and reduce environmental pollution.

[0005] However, existing research is not comprehensive enough, and there are still some unsolved problems, such as rice husk ash (agricultural waste, containing more than 90% amorphous SiO2) can be used as a low-cost silicon source after mechanical activation, but direct incorporation can easily cause agglomeration, which cannot fully utilize the high silicon source activity and filling effect, and cannot effectively improve the mechanical properties of geopolymer.

[0006] Therefore, based on the application of rice husk ash in geopolymer to improve its strength, a new process for preparing nano-silicon dioxide by modifying rice husk ash is developed. The nano-silicon dioxide prepared by this process can realize uniform particle size and effectively improve the strength of geopolymer. The batch stability process can be realized by using a simple process to prepare geopolymer. SUMMARY

[0007] Technical problems solved by the present application: The technical problems to be solved by the present application are to provide a lithium residue based geopolymer, which can form a more uniform, higher cross-linking degree, and more optimal silicon-aluminum ratio geopolymer gel network based on rice husk ash nanomaterials, significantly improve the mechanical strength of the geopolymer, and realize the stability between batches and the stability of strength improvement.

[0008] Technical scheme: The lithium residue based geopolymer based on rice husk ash nanomodified material is characterized in that, the geopolymer comprises 10-25% of rice husk ash nanomodified material and 75-90% of powder component, based on 100% of total mass.

[0009] The rice husk ash nanomodified material is prepared by the following steps: 24-35% of rice husk ash, 60-75% of lye, and 1-5% of nanosilica are mixed, water with a mass ratio of 3-5:1 to the rice husk ash is added, and the mixture is reacted at 150-250 DEG C for 4-6 h to obtain the rice husk ash nanomodified material.

[0010] The present application is based on the powder component composed of lithium residue, fly ash, slag powder and calcium-based material, adds rice husk ash as a silicon source, and modifies it by a specific process, i.e. dissolves it in lye, accelerates the dissolution leaching under high temperature conditions, and at the same time adds nanosilica as a guide core to form nanosilica particles with uniform particle size, which on the one hand avoids the non-uniformity and easy agglomeration of the silica particles prepared from rice husk ash, thereby affecting the strength improvement of the prepared geopolymer and causing the instability of the geopolymer strength; on the other hand, based on the preparation of nanosilica particles guided by nanosilica, the high activity, small size effect and filling effect of the nanosilica particles are utilized to effectively stimulate the potential cementitious activity of lithium residue, build a high-density nanocomposite geopolymer, and increase the contact reaction sites with the powder material; it can also be used as an effective site for geopolymer gel nucleation and growth, accelerate the precipitation and growth process of the gel phase, shorten the setting time, significantly improve the early strength of the geopolymer, and ultimately promote the formation of more early and more N-A-S-H (sodium aluminum silicate) or K-A-S-H (potassium aluminum silicate) gel.

[0011] In addition, the rice husk ash nanomodified material of the present application is combined with the powder component to prepare the geopolymer in the form of a suspension with uniform particle size, which can effectively improve the uniform dispersion of nanosilica in the system and balance the silicon-aluminum ratio in the system, thereby helping to form a more uniform, higher cross-linking degree, and more optimal silicon-aluminum ratio geopolymer gel network, and significantly improve the mechanical strength (compressive and flexural) of the geopolymer.

[0012] Further, the powder component of the geopolymer according to the present application comprises lithium residue 55-65%, fly ash 13-17%, slag powder 10-12%, and calcium-based material 12-16% in total 100% by mass fraction.

[0013] Further, the nano-silica of the geopolymer according to the present application has a particle size of 10-150 nm and a specific surface area of 120-300 m 2 / g.

[0014] Further, the geopolymer according to the present application uses an alkali liquor of sodium hydroxide or calcium hydroxide with a mass concentration of 25-30%.

[0015] Further, the lithium residue of the geopolymer according to the present application contains SiO2 20-30%, CaO 15-25%, Al2O3 10-25%, and SO3 10-20%.

[0016] Further, the fly ash of the geopolymer according to the present application contains SiO2 42-61%, Al2O3 20-30%, and CaO 5-18%.

[0017] Further, the slag powder of the geopolymer according to the present application contains CaO 40-50%, SiO2 30-40%, and Al2O3 7-15%.

[0018] Further, the calcium-based material of the geopolymer according to the present application is selected from at least one of calcium oxide, calcium hydroxide, calcium sulfate, or calcium carbonate.

[0019] The method for preparing the above-mentioned lithium residue-based geopolymer according to the present application comprises the following steps:

[0020] (1) uniformly stirring the powder component with water according to the water-cement ratio, adding rice husk ash nano-modified material, and stirring in a cement paste stirrer to obtain lithium residue-based geopolymer slurry;

[0021] (2) placing the lithium residue-based geopolymer slurry into a mold, demolding, and curing to obtain lithium residue-based geopolymer.

[0022] Further, in step (1) of the geopolymer according to the present application, the water-cement ratio is 0.2-0.4; and in step (2), the curing time is 7-28 d.

[0023] Beneficial Effects: Compared with existing technologies, the present invention offers significant advantages: the geopolymer, based on modified rice husk ash, can set within 120-200 minutes, shortening the setting time by 35%. Despite this shortened setting time, the geopolymer still achieves a 7-day compressive strength exceeding 25 MPa, high early strength, and a 28-day compressive strength exceeding 40 MPa, with no subsequent strength loss. Furthermore, the strength of each batch of geopolymer produced is stable, with no significant fluctuations, achieving batch stability consistent with industrial production. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described in detail below with reference to the embodiments.

[0025] It should be noted that the nano-silicon dioxide used in the present invention has a particle size of 10-150 nm and a specific surface area of ​​120-300 m 2 / g.

[0026] It should be noted that for geopolymers in this field, the fluctuation range of their 7d compressive strength within the range of ±2MPa is considered a stable fluctuation range; the fluctuation range of their 28d compressive strength within the range of ±3MPa is considered a stable fluctuation range.

[0027] The main component contents of lithium slag, fly ash and slag powder used in the following Examples 1 and 2 and Comparative Examples 1 and 2 of the present invention are shown in Tables 1 to 3 below.

[0028] Table 1 Main component content of lithium slag

[0029] Component SiO2 CaO Al2O3 SO3 Content / % 27.5 19.6 19.8 15.7

[0030] Table 2 Main components of fly ash

[0031] Component SiO2 CaO Al2O3 SO3 Content / % 43.5 9.92 25.5 2.5

[0032] Table 3 Main components of slag powder

[0033] Component SiO2 CaO Al2O3 SO3 Content / % 31.2 43.6 18.5 0.88

[0034] Example 1

[0035] The lithium slag-based geopolymer of Example 1 comprises 15% of rice husk ash nano-modified material and 85% of powder components, based on a total mass fraction of 100%.

[0036] The rice husk ash nano-modified material comprises 30% rice husk ash, 68% alkali solution and 2% nano-silicon dioxide based on a total mass fraction of 100%, and the alkali solution is a sodium hydroxide solution with a mass concentration of 30%.

[0037] The powder components, based on a total mass fraction of 100%, include 60% of lithium slag, 15% of fly ash, 10% of slag powder and 15% of calcium oxide.

[0038] The preparation method of the lithium slag-based geopolymer comprises the following steps:

[0039] (1) Preparation of rice husk ash nano-modified material: Rice husk ash, strong sodium oxide solution and nano-silicon dioxide were mixed, and an appropriate amount of water was added to control the reaction liquid-solid ratio to be 3:1 (i.e., the mass ratio of water to rice husk ash). The mixture was poured into a high-temperature and high-pressure reactor and reacted at 200°C for 6 hours to obtain a rice husk ash nano-modified suspension.

[0040] (2) lithium slag, fly ash, slag powder, and calcium oxide were simultaneously placed in a ball mill and milled for 2 minutes to prepare a mixed powder;

[0041] (3) mixing the mixed powder at a water-cement ratio of 0.3, adding the rice husk ash nano-modified material, and stirring in a cement slurry mixer to obtain a lithium slag-based geopolymer slurry;

[0042] (4) After the lithium slag-based geopolymer slurry is placed in a mold, it is scraped flat and vibrated on a vibration table to remove air. After demolding, it is cured in a curing box for 7 days and 28 days to obtain a high-strength lithium slag-based geopolymer.

[0043] Comparative Example 1

[0044] The difference between Comparative Example 1 and Example 1 is that nano-silicon dioxide is not added when modifying rice husk ash. The specific steps include:

[0045] (1) Preparation of rice husk ash nano-modified material: Mix rice husk ash with sodium hydroxide solution, add appropriate amount of water, control the reaction liquid-solid ratio to 3:1 (i.e., the mass ratio of water to rice husk ash), pour it into a high-temperature and high-pressure reactor, and react at 200°C for 6 hours to obtain a rice husk ash nano-modified suspension; based on the total mass fraction of 100%, rice husk ash accounts for 35% and alkali solution accounts for 65%, and the alkali solution is a sodium hydroxide solution with a mass concentration of 30%.

[0046] (2) lithium slag, fly ash, slag powder, and calcium oxide were simultaneously placed in a ball mill and milled for 2 minutes to prepare a mixed powder;

[0047] (3) mixing the mixed powder at a water-cement ratio of 0.3, adding the rice husk ash nano-modified material, and stirring in a cement slurry mixer to obtain a lithium slag-based geopolymer slurry;

[0048] (4) After the lithium slag-based geopolymer slurry is placed in a mold, it is scraped flat and vibrated on a vibration table to remove air. After demolding, it is cured in a curing box for 7 days and 28 days to obtain a high-strength lithium slag-based geopolymer.

[0049] Example 2

[0050] The lithium slag-based geopolymer of this example 2 includes rice husk ash nano-modified material 15% and powder component 85% in total mass fraction of 100%.

[0051] The rice husk ash nano-modified material includes 25% of rice husk ash, 70% of lye and 5% of nano-silica in total mass fraction of 100%.

[0052] The powder component includes 62% of lithium slag, 13% of fly ash, 12% of slag powder and 13% of calcium oxide in total mass fraction of 100%.

[0053] The preparation method of the lithium slag-based geopolymer includes the following steps:

[0054] (1) Preparation of rice husk ash nano-modified material: mix rice husk ash, strong sodium oxide solution and nano-silica, add appropriate amount of water to control the solid-liquid ratio of the reaction solution to 4:1 (i.e. the mass ratio of water to rice husk ash), pour into a high-temperature high-pressure reaction kettle, react at 200℃ for 6h, and prepare a rice husk ash nano-modified suspension;

[0055] (2) Put lithium slag, fly ash, slag powder and calcium oxide into a ball mill at the same time and ball mill for 2min to prepare a mixed powder;

[0056] (3) Stir the mixed powder uniformly according to the water-cement ratio of 0.3, add the rice husk ash nano-modified material, and stir in a cement paste stirrer to obtain a lithium slag-based geopolymer slurry;

[0057] (4) After the lithium slag-based geopolymer slurry is put into a mold, it is scraped flat and vibrated on a vibrating table to remove air, and after demolding, it is cured in a curing box for 7d and 28d to obtain a high-strength lithium slag-based geopolymer.

[0058] Comparative Example 2

[0059] The difference between the comparative example 2 and the example 2 is that no nano-silica is added when modifying the rice husk ash. Specifically, it includes the following steps:

[0060] (1) Preparation of rice husk ash nano-modified material: mix rice husk ash and strong sodium oxide solution, add appropriate amount of water to control the solid-liquid ratio of the reaction solution to 4:1 (i.e. the mass ratio of water to rice husk ash), pour into a high-temperature high-pressure reaction kettle, react at 200℃ for 6h, and prepare a rice husk ash nano-modified suspension; the proportion of rice husk ash is 32% and the proportion of lye is 68% in total mass fraction of 100%, and the lye is a calcium hydroxide solution with a mass concentration of 30%.

[0061] (2) Put the lithium slag, fly ash, slag powder and calcium oxide into the ball mill at the same time and ball mill for 2 minutes to prepare a mixed powder;

[0062] (3) Stir the mixed powder uniformly according to a water-cement ratio of 0.3, add the rice husk ash nano-modified material, and stir in a cement paste stirrer to obtain a lithium slag-based geopolymer slurry;

[0063] (4) After the lithium slag-based geopolymer slurry is put into a mold, it is scraped and vibrated on a vibrating table to remove air, and after demolding, it is cured in a curing box for 7 days and 28 days to obtain a high-strength lithium slag-based geopolymer.

[0064] The lithium slag-based geopolymers prepared in Examples 1 and 2 and Comparative Examples 1 and 2 are subjected to mechanical property detection, and the obtained results are shown in Table 4.

[0065] Table 4: Mechanical property test table of Examples 1-2 and Comparative Examples 1-2

[0066]

[0067] It can be seen from Table 4 that the 7d strength of the geopolymer prepared in Examples 1 and 2 can reach more than 25Mpa, and the 28d compressive strength can reach more than 40Mpa. Compared with Comparative Examples 1 and 2, the 7d strength difference is about 60%, and the 28d compressive strength difference is about 40%, while the added modified silicon dioxide content is basically the same. Therefore, it is indirectly verified that the uniformity of the particle size is crucial when preparing the rice husk ash nano-modified material.

[0068] The main component contents of the lithium slag, fly ash and slag powder used in the following Examples 3 to 5 and Comparative Examples 3 to 5 of the present application are shown in Tables 5 to 7.

[0069] Table 5: Main component content of lithium slag

[0070] Component SiO2 CaO Al2O3 SO3 Content / % 21.7 23.8 12.88 19.2

[0071] Table 6: Main component content of fly ash

[0072] Component SiO2 CaO Al2O3 SO3 Content / % 51.6 13.8 21.6 1.2

[0073] Table 7: Main component content of slag powder

[0074] Component SiO2 CaO Al2O3 <![CDATA[SO3]]> Content / % Component CaO Content / % 31.2 45.1 12.9 0.56

[0075] Example 3

[0076] The lithium slag-based geopolymer of this embodiment 3 comprises rice husk ash nano-modified material 20% and powder component 80% in total mass fraction of 100%.

[0077] The rice husk ash nano-modified material comprises 32% of rice husk ash, 65% of lye and 3% of nano-silica in total mass fraction of 100%.

[0078] The powder component comprises 58% of lithium slag, 17% of fly ash, 11% of slag powder and 14% of calcium oxide in total mass fraction of 100%.

[0079] The preparation method of the lithium slag-based geopolymer comprises the following steps:

[0080] (1) Preparation of rice husk ash nano-modified material: mix rice husk ash, strong sodium oxide solution and nano-silica, add appropriate amount of water to control the solid-liquid ratio of the reaction solution to 3.5:1 (i.e. the mass ratio of water to rice husk ash), pour into a high-temperature high-pressure reaction kettle, react at 220°C for 5h, and prepare a rice husk ash nano-modified suspension;

[0081] (2) Put lithium slag, fly ash, slag powder and calcium oxide into a ball mill at the same time and ball mill for 3min to prepare a mixed powder;

[0082] (3) Stir the mixed powder uniformly according to the water-cement ratio of 0.3, add the rice husk ash nano-modified material, and stir in a cement paste stirrer to obtain lithium slag-based geopolymer slurry;

[0083] (4) After the lithium slag-based geopolymer slurry is put into a mold, it is scraped flat and vibrated on a vibrating table to remove air, and after demolding, it is cured in a curing box for 7d and 28d to obtain high-strength lithium slag-based geopolymer.

[0084] Comparative example 3

[0085] The difference between this comparative example 3 and embodiment 3 is that no nano-silica is added when modifying the rice husk ash. Specifically, it comprises the following steps:

[0086] (1) Preparation of rice husk ash nano-modified material: mix rice husk ash and strong sodium oxide solution, add appropriate amount of water to control the solid-liquid ratio of the reaction solution to 3.5:1 (i.e. the mass ratio of water to rice husk ash), pour into a high-temperature high-pressure reaction kettle, react at 220°C for 5h, and prepare a rice husk ash nano-modified suspension; the rice husk ash accounts for 37% and the lye accounts for 63% in total mass fraction of 100%, and the lye is a calcium hydroxide solution with a mass concentration of 30%.

[0087] (2) Put lithium slag, fly ash, slag powder and calcium oxide into a ball mill at the same time and ball mill for 3min to prepare a mixed powder;

[0088] (3) The mixed powder is stirred uniformly according to a water-cement ratio of 0.3, the rice husk ash nano-modified material is added, and stirring is performed in a cement paste stirrer to obtain lithium slag-based geopolymer slurry;

[0089] (4) After the lithium slag-based geopolymer slurry is placed in a mold, it is leveled and vibrated on a vibrating table to remove air, and after demolding, it is cured in a curing box for 7d and 28d to obtain high-strength lithium slag-based geopolymer.

[0090] Example 4

[0091] The lithium slag-based geopolymer of this example 4 comprises, in terms of total mass fraction of 100%, 10% of rice husk ash nano-modified material and 90% of powder component.

[0092] The rice husk ash nano-modified material comprises, in terms of total mass fraction of 100%, 24% of rice husk ash, 75% of lye and 1% of nano-silicon dioxide, and the lye is a calcium hydroxide solution with a mass concentration of 25%.

[0093] The powder component comprises, in terms of total mass fraction of 100%, 55% of lithium slag, 17% of fly ash, 12% of slag powder and 16% of calcium oxide.

[0094] The preparation method of the lithium slag-based geopolymer comprises the following steps:

[0095] (1) Preparation of rice husk ash nano-modified material: rice husk ash, strong sodium oxide solution and nano-silicon dioxide are mixed, an appropriate amount of water is added to control the solid-liquid ratio of the reaction solution to be 3:1 (i.e. the mass ratio of water to rice husk ash), and then poured into a high-temperature and high-pressure reaction kettle, and reacted at 150℃ for 6h to prepare a rice husk ash nano-modified suspension;

[0096] (2) The lithium slag, fly ash, slag powder and calcium oxide are simultaneously placed in a ball mill and ball milled for 3min to prepare a mixed powder;

[0097] (3) The mixed powder is stirred uniformly according to a water-cement ratio of 0.3, the rice husk ash nano-modified material is added, and stirring is performed in a cement paste stirrer to obtain lithium slag-based geopolymer slurry;

[0098] (4) After the lithium slag-based geopolymer slurry is placed in a mold, it is leveled and vibrated on a vibrating table to remove air, and after demolding, it is cured in a curing box for 7d and 28d to obtain high-strength lithium slag-based geopolymer.

[0099] Comparative Example 4

[0100] The difference between this comparative example 4 and example 4 is that no nano-silicon dioxide is added when modifying the rice husk ash. Specifically, it comprises the following steps:

[0101] (1) Preparation of rice husk ash nano-modified material: mix rice husk ash with strong sodium hydroxide solution, add appropriate amount of water to control the solid-liquid ratio of the reaction solution to be 3:1 (i.e. the mass ratio of water to rice husk ash), pour into a high-temperature high-pressure reaction kettle, react at 150°C for 6h, and prepare a rice husk ash nano-modified suspension; based on a total mass fraction of 100%, the proportion of rice husk ash is 27%, and the proportion of lye is 73%, and the lye is a calcium hydroxide solution with a mass concentration of 25%.

[0102] (2) Put lithium slag, fly ash, slag powder and calcium oxide into the ball mill at the same time and ball mill for 3 minutes to prepare a mixed powder;

[0103] (3) Stir the mixed powder uniformly according to a water-cement ratio of 0.3, add the rice husk ash nano-modified material, and stir in a cement paste stirrer to obtain a lithium slag-based geopolymer slurry;

[0104] (4) After placing the lithium slag-based geopolymer slurry in a mold, scrape it flat and vibrate it on a vibrating table to remove air, demold it and cure it in a curing box for 7 days and 28 days to obtain a high-strength lithium slag-based geopolymer.

[0105] Example 5

[0106] The lithium slag-based geopolymer of this example 5 includes, based on a total mass fraction of 100%, 25% of rice husk ash nano-modified material and 75% of powder component.

[0107] Among them, the rice husk ash nano-modified material includes, based on a total mass fraction of 100%, 35% of rice husk ash, 60% of lye and 5% of nano-silicon dioxide, and the lye is a calcium hydroxide solution with a mass concentration of 25%.

[0108] The powder component includes, based on a total mass fraction of 100%, 65% of lithium slag, 13% of fly ash, 10% of slag powder and 12% of calcium oxide.

[0109] The preparation method of the lithium slag-based geopolymer includes the following steps:

[0110] (1) Preparation of rice husk ash nano-modified material: mix rice husk ash, strong sodium hydroxide solution and nano-silicon dioxide, add appropriate amount of water to control the solid-liquid ratio of the reaction solution to be 4:1 (i.e. the mass ratio of water to rice husk ash), pour into a high-temperature high-pressure reaction kettle, react at 250°C for 4h, and prepare a rice husk ash nano-modified suspension;

[0111] (2) Put lithium slag, fly ash, slag powder and calcium oxide into the ball mill at the same time and ball mill for 3 minutes to prepare a mixed powder;

[0112] (3) Stir the mixed powder uniformly according to a water-cement ratio of 0.3, add the rice husk ash nano-modified material, and stir in a cement paste stirrer to obtain a lithium slag-based geopolymer slurry;

[0113] (4) After the lithium slag-based geopolymer slurry is placed in a mold, it is scraped flat and vibrated on a vibration table to remove air. After demolding, it is cured in a curing box for 7 days and 28 days to obtain a high-strength lithium slag-based geopolymer.

[0114] Comparative Example 5

[0115] The difference between Comparative Example 5 and Example 5 is that nano-silicon dioxide is not added when modifying the rice husk ash. The specific steps include:

[0116] (1) Preparation of rice husk ash nano-modified material: Rice husk ash was mixed with a strong sodium oxide solution, and an appropriate amount of water was added to control the reaction liquid-solid ratio to 4:1 (i.e., the mass ratio of water to rice husk ash). The mixture was poured into a high-temperature and high-pressure reactor and reacted at 250°C for 4 hours to obtain a rice husk ash nano-modified suspension. Based on the total mass fraction of 100%, rice husk ash accounted for 42% and alkali solution accounted for 58%, and the alkali solution was a calcium hydroxide solution with a mass concentration of 25%.

[0117] (2) lithium slag, fly ash, slag powder, and calcium oxide were simultaneously placed in a ball mill and milled for 3 minutes to prepare a mixed powder;

[0118] (3) mixing the mixed powder at a water-cement ratio of 0.3, adding the rice husk ash nano-modified material, and stirring in a cement slurry mixer to obtain a lithium slag-based geopolymer slurry;

[0119] (4) After the lithium slag-based geopolymer slurry is placed in a mold, it is scraped flat and vibrated on a vibration table to remove air. After demolding, it is cured in a curing box for 7 days and 28 days to obtain a high-strength lithium slag-based geopolymer.

[0120] The mechanical properties of the lithium slag-based geopolymers prepared in Examples 3 to 5 and Comparative Examples 3 to 5 were tested, and the results obtained are shown in Table 8 below.

[0121] Table 8 Mechanical properties test table of Examples 3-5 and Comparative Examples 3-5

[0122]

[0123]

[0124] Compared with Comparative Examples 3 to 5, the 7d strength difference is about 60%, and the 28d compressive strength difference is about 50% on the basis of basically maintaining the difference in the added modified silicon dioxide content. Thus, it is indirectly verified that the uniformity of the particle size is crucial to the performance when the rice husk ash nano-modified material is prepared.

[0125] Comparative Example 6-Comparative Example 7

[0126] Comparative Example 6 and Comparative Example 7 use the same preparation process and parameters of Comparative Example 1 to prepare the geopolymer, that is, three batches of experiments are respectively carried out under the experimental conditions of Comparative Example 1, and the obtained results are shown in Table 9.

[0127] Table 9 Mechanical property test table of Comparative Example 1, Comparative Example 6 and Comparative Example 7

[0128]

[0129] Compared with Comparative Examples 3 to 5, the 7d strength difference is about 60%, and the 28d compressive strength difference is about 50% on the basis of basically maintaining the difference in the added modified silicon dioxide content. Thus, it is indirectly verified that the uniformity of the particle size is crucial to the performance when the rice husk ash nano-modified material is prepared.

Claims

1. A lithium slag-based geopolymer based on rice husk ash nano-modified material, characterized in that: The geopolymer comprises 10-25% of rice husk ash nano-modified material and 75-90% of powder component based on a total mass fraction of 100%; The rice husk ash nano-modified material is prepared by the following steps: based on a total mass fraction of 100%, 24-35% of rice husk ash, 60-75% of alkali solution and 1-5% of nano-silicon dioxide are mixed, water is added at a mass ratio of (3-5):1 to rice husk ash, and the mixture is reacted at 150-250° C. for 4-6 hours to obtain the rice husk ash nano-modified material.

2. The lithium slag-based geopolymer according to claim 1, wherein The powder components, calculated based on a total mass fraction of 100%, include 55-65% of lithium slag, 13-17% of fly ash, 10-12% of slag powder and 12-16% of calcium-based materials.

3. The lithium slag-based geopolymer according to claim 1, wherein The particle size of the nano-silicon dioxide is 10-150nm, and the specific surface area is 120-300m 2 / g.

4. The lithium slag-based geopolymer according to claim 1, wherein The alkali solution is a sodium hydroxide or calcium hydroxide solution with a mass concentration of 25-30%.

5. The lithium slag-based geopolymer according to claim 2, wherein The lithium slag has a SiO2 content of 20-30%, a CaO content of 15-25%, an Al2O3 content of 10-25%, and a SO3 content of 10-20%.

6. The lithium slag-based geopolymer according to claim 2, characterized in that The fly ash contains SiO2 at a content of 42-61%, Al2O3 at a content of 20-30%, and CaO at a content of 5-18%.

7. The lithium slag-based geopolymer according to claim 2, characterized in that The slag powder contains 40-50% CaO, 30-40% SiO2 and 7-15% Al2O3.

8. The lithium slag-based geopolymer according to claim 2, characterized in that The calcium-based material is selected from at least one of calcium oxide, calcium hydroxide, calcium sulfate or calcium carbonate.

9. A method for preparing the lithium slag-based geopolymer according to claim 1, characterized in that: The steps include: (1) adding water to the powder components according to the water-cement ratio and stirring evenly, adding the rice husk ash nano-modified material, and stirring in a cement slurry mixer to obtain a lithium slag-based geopolymer slurry; (2) putting the lithium slag-based geopolymer slurry into a mold, demoulding, and curing the mold to obtain the lithium slag-based geopolymer.

10. The method for preparing a lithium slag-based geopolymer according to claim 9, wherein: In step (1), the water-cement ratio is 0.2-0.4; in step (2), the curing time is 7-28 days.

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