Concrete based on high-doped lithium slag and preparation method thereof

Abstract

The present invention discloses a concrete based on high-doping lithium slag and a preparation method thereof, belonging to the field of concrete technology. The preparation method comprises the following steps: S1: obtaining lithium slag powder, and mixing the lithium slag powder with an activator, stirring evenly and then curing to obtain modified lithium slag; S2: mixing the modified lithium slag with cement, fine aggregate and coarse aggregate to obtain a mixture; S3: adding water to the mixture, and continuously stirring until there is no segregation and no bleeding to obtain the concrete. The present invention can improve the crack resistance and freeze-thaw resistance of concrete while achieving a high doping amount of lithium slag, thereby extending the service life of the highway subgrade and promoting technological progress and sustainable development in the highway construction industry; in addition, the present invention also has a certain carbon dioxide removal capacity, which makes a certain contribution to reducing carbon dioxide in automobile exhaust emissions and helps to alleviate the greenhouse effect.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete, and in particular to concrete based on high-doped lithium slag and a preparation method thereof. Background Art

[0002] With rapid economic development and accelerated urbanization, the scale of highway construction continues to expand, and the demand for roadbed materials is also increasing. Traditional roadbed materials rely primarily on natural sand and gravel, which not only leads to huge resource consumption but also causes rising costs. Conventional roadbed concrete has also exposed many problems in actual application, such as easy cracking and insufficient freeze-thaw resistance, which seriously affect the durability and service life of the highway. In addition, large amounts of industrial solid waste, such as fly ash, slag, and especially lithium slag (the waste residue after lithium salt extraction), have low utilization rates and are accumulated in large quantities, causing serious pollution to the environment.

[0003] While some attempts have been made to incorporate industrial solid waste into roadbed materials, the slag content is typically less than 20%. Excessive slag content can affect the roadbed's load-bearing capacity, permeability, and stability. Lithium slag, due to its complex composition, containing multiple elements such as lithium, silicon, and aluminum, has been the subject of significant research. Current research focuses on chemical lithium extraction and its applications in other areas, such as soil conditioners. However, it has yet to be widely used in roadbed materials. Summary of the Invention

[0004] In view of the above problems, the present invention aims to provide a concrete based on high-doped lithium slag and a preparation method thereof.

[0005] The technical solutions of the present invention are as follows:

[0006] In one aspect, a method for preparing concrete based on highly doped lithium slag is provided, comprising the following steps:

[0007] S1: obtaining lithium slag powder, mixing the lithium slag powder with an activator, stirring evenly, and then curing to obtain modified lithium slag;

[0008] S2: mixing the modified lithium slag with cement, fine aggregate and coarse aggregate to obtain a mixture;

[0009] S3: adding water to the mixture and continuously stirring until there is no segregation or bleeding, thereby obtaining the concrete.

[0010] Preferably, in step S1, the particle size of the lithium slag powder is less than 0.075 mm, and the specific surface area is 400-500 m 2 / kg, Li2O content is 2.5-3.5%, SiO2 content is 45-55%, and Al2O3 content is 15-20%.

[0011] Preferably, step S1 further includes a step of drying the lithium slag powder, the drying temperature is 100-120° C., and the drying time is 2-3 hours.

[0012] Preferably, in step S1, mechanical stirring is used for mixing, and the stirring speed is 100-300 r / min.

[0013] Preferably, in step S1, curing is performed at 80-100° C. for 24-36 hours.

[0014] Preferably, in step S1, the mass of the lithium slag powder is 30-50% of the mass of the cement, and the mass of the activator is 3-5% of the mass of the cement; in step S2, the mass ratio of the modified lithium slag to cement, fine aggregate and coarse aggregate is 0.33-0.55:1:1.5-2:2.5-3; in step S3, the mass of the water is 40-50% of the mass of the cement.

[0015] Preferably, in step S1, the activator is composed of an inorganic activator and an organic activator in a mass ratio of 2-4:1.

[0016] Preferably, the inorganic activator is any one or more of sodium sulfate, potassium sulfate, calcium sulfate, potassium phosphate, and calcium fluorosilicate.

[0017] Preferably, the organic activator is triethanolamine and / or calcium lignin sulfonate.

[0018] On the other hand, a concrete based on highly doped lithium slag is also provided, which is prepared by using any of the above methods for preparing concrete based on highly doped lithium slag.

[0019] The beneficial effects of the present invention are:

[0020] The present invention realizes the application of high-doping amount of lithium slag, converts industrial waste slag into valuable building materials, reduces the storage of lithium slag and pollution to the environment, and at the same time reduces dependence on natural resources, meeting the requirements of sustainable development; the present invention can improve the crack resistance and freeze-thaw resistance of concrete while achieving high-doping amount of lithium slag, thereby extending the service life of highway roadbed and promoting technological progress and sustainable development in the highway construction industry; in addition, the present invention also has a certain carbon dioxide removal ability, makes a certain contribution to reducing carbon dioxide in automobile exhaust emissions, and helps to alleviate the greenhouse effect. DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to the embodiments. It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those commonly understood by those of ordinary skill in the art to which this application belongs. The words "including" or "comprising" and the like used in the present invention are intended to mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0022] In one aspect, the present invention provides a method for preparing concrete based on highly doped lithium slag, comprising the following steps:

[0023] S1: obtaining lithium slag powder, mixing the lithium slag powder with an activator, stirring evenly and then curing to obtain modified lithium slag.

[0024] In a specific embodiment, the particle size of the lithium slag powder is less than 0.075 mm, and the specific surface area is 400-500 m 2 / kg, Li2O content is 2.5-3.5%, SiO2 content is 45-55%, and Al2O3 content is 15-20%.

[0025] In a specific embodiment, step S1 further includes drying the lithium slag powder at a temperature of 100-120° C. for 2-3 hours. In this embodiment, drying the lithium slag powder can remove excess moisture from the lithium slag powder, preventing it from affecting the water-cement ratio of the concrete during the subsequent concrete preparation process. Furthermore, it can enhance the activation effect of the active components of the lithium slag powder, thereby more effectively participating in the cement hydration reaction, generating more hydration products, and improving the performance of the concrete.

[0026] In a specific embodiment, the mixing is performed by mechanical stirring at a stirring speed of 100-300 r / min.

[0027] In a specific embodiment, the curing is performed at 80-100° C. for 24-36 hours.

[0028] In a specific embodiment, the stimulant is composed of an inorganic stimulant and an organic stimulant in a mass ratio of 2-4: 1. Optionally, the inorganic stimulant is any one or more of sodium sulfate, potassium sulfate, calcium sulfate, potassium phosphate, and calcium fluorosilicate, and the organic stimulant is triethanolamine and / or calcium lignin sulfonate.

[0029] S2: mixing the modified lithium slag with cement, fine aggregate and coarse aggregate to obtain a mixture.

[0030] It should be noted that the fine aggregate and coarse aggregate in concrete are existing technologies, and the specific components will not be described here.

[0031] S3: adding water to the mixture and continuously stirring until there is no segregation or bleeding, thereby obtaining the concrete.

[0032] In a specific embodiment, in step S1, the mass of the lithium slag powder is 30-50% of the mass of the cement, and the mass of the activator is 3-5% of the mass of the cement; in step S2, the mass ratio of the modified lithium slag to cement, fine aggregate and coarse aggregate is 0.33-0.55:1:1.5-2:2.5-3; in step S3, the mass of the water is 40-50% of the mass of the cement.

[0033] In the present invention, after the lithium slag powder is modified by the activator, its active ingredients are fully activated and undergo a secondary hydration reaction with cement hydration products to generate a large number of stable hydration products, such as hydrated calcium silicate and hydrated calcium aluminate. These hydration products fill the pores inside the concrete, refine the pore structure, and improve the density of the concrete, thereby significantly improving the compressive strength and flexural strength. At the same time, the fine pore structure reduces the intrusion channels of moisture and harmful substances, enhances the stability of the concrete in freeze-thaw cycles and chemical corrosion environments, and thus improves the freeze-thaw resistance and durability.

[0034] Lithium slag also contains alkaline oxides (such as CaO and MgO), which can react chemically with carbon dioxide to form carbonate compounds. For example, CaO reacts with CO2 to form CaCO3. This chemical reaction absorbs carbon dioxide and can, to a certain extent, reduce carbon dioxide emissions from vehicle exhaust.

[0035] On the other hand, the present invention further provides a concrete based on highly doped lithium slag, which is prepared by any of the above methods for preparing concrete based on highly doped lithium slag.

[0036] Example 1

[0037] A concrete based on highly doped lithium slag is prepared by the following steps:

[0038] (1) obtaining lithium slag powder and drying the lithium slag powder;

[0039] In this embodiment, the particle size of the lithium slag powder is less than 0.075 mm, and the specific surface area is 450 m 2 / kg, Li2O content is 3%, SiO2 content is 50%, Al2O3 content is 18%. The drying temperature is 110℃ and the drying time is 2.5h.

[0040] (2) mixing the lithium slag powder and the activator, stirring them evenly and then curing them to obtain modified lithium slag;

[0041] In this example, the amount of lithium slag powder used is 190 kg, and the amount of activator used is 15.3 kg. The activator is composed of 3.1 kg of sodium sulfate, 7.1 kg of potassium sulfate, and 5.1 kg of triethanolamine (i.e., the mass ratio of inorganic activator to organic activator is 2:1). During mixing, the lithium slag powder and activator are added to a mixer and stirred at 200 r / min for 15 minutes. The mixture is then placed in a constant temperature curing box and cured at 90°C for 24 hours to obtain the modified lithium slag.

[0042] (3) 205.3 kg of the modified lithium slag, 380 kg of cement, 700 kg of fine aggregate, and 1100 kg of coarse aggregate were added to a mixer and mixed for 45 seconds to obtain a mixture.

[0043] (4) 171 kg of water was added to the mixer and the mixing was continued for 150 s. At this time, there was no segregation or bleeding, and the concrete was obtained.

[0044] Example 2

[0045] Different from Example 1, the activator in step (2) of this example consists of 4.4 kg of sodium sulfate, 7 kg of potassium phosphate and 3.8 kg of calcium lignin sulfonate (i.e., the mass ratio of the inorganic activator to the organic activator is 3:1).

[0046] Example 3

[0047] Different from Example 1, the amount of lithium slag powder used in step (2) of this embodiment is 114 kg (i.e., the mass of lithium slag powder is 30% of the mass of cement), and the amount of the activator used is 11.4 kg (i.e., the mass of the activator is 3% of the mass of cement).

[0048] Example 4

[0049] Different from Example 1, the curing temperature in step (2) of this example is 100°C.

[0050] Example 5

[0051] Different from Example 1, the activator in step (2) of this embodiment consists of 5.2 kg of potassium sulfate, 10 kg of calcium fluorosilicate and 3.8 kg of triethanolamine (i.e., the mass ratio of the inorganic activator to the organic activator is 4:1), the amount of lithium slag powder used in step (2) of this embodiment is 152 kg (i.e., the mass of the lithium slag powder is 40% of the mass of the cement), the amount of the activator used is 19 kg (i.e., the mass of the activator is 5% of the mass of the cement), and the curing temperature in step (2) of this embodiment is 80°C.

[0052] Comparative Example 1

[0053] Different from Example 1, the activator in step (2) of this example consists of only 4.65 kg of sodium sulfate and 10.65 kg of potassium sulfate.

[0054] Comparative Example 2

[0055] Different from Example 1, the exciter in step (2) of this example consists of only 15.3 kg of triethanolamine.

[0056] Comparative Example 3

[0057] Different from Example 1, the activator in step (3) of this example consists of 3.1 kg of calcium hydroxide, 7.1 kg of aluminum sulfate 18-hydrate and 5.1 kg of triethanolamine.

[0058] Comparative Example 4

[0059] Different from Example 1, the stimulator in step (2) of this example consists of 3.1 kg of sodium sulfate, 7.1 kg of potassium sulfate and 5.1 kg of coconut oil diethanolamide.

[0060] The concrete of each embodiment and each comparative example is poured and cured to obtain the finished product. Specifically: the concrete is poured into the formwork in layers, the thickness of each layer is controlled at 250mm, and an inserted vibrator is used for vibration. The vibration time is 15s / point, and the spacing between vibration points is controlled at 350mm. After the pouring is completed, the concrete surface is immediately smoothed (first use a wooden trowel for preliminary smoothing, and then use an iron trowel for secondary smoothing to ensure that the concrete surface is flat, smooth, and has no obvious defects); then it is cured at room temperature (20-25°C) for 7 days. During the curing period, watering is used to keep the concrete surface moist. The number of watering times per day is determined according to the weather conditions, generally 3-4 times. The finished product was subjected to performance testing, and the test results are shown in Table 1:

[0061] Table 1 Performance test results of concrete in various embodiments and comparative examples

[0062]

[0063] As can be seen from Table 1, the concrete based on the highly doped lithium slag of the present invention exhibits excellent compressive strength, carbon dioxide removal rate, flexural tensile strength, freeze-thaw resistance, and chloride ion permeability resistance, based on the highly doped lithium slag, and can meet the application requirements of highway subgrade. Concrete produced using only inorganic activators, only organic activators, or a composite activator containing both organic and inorganic activators, as defined in the present invention, cannot achieve the excellent results achieved by the present invention.

[0064] It should be noted that the above embodiments are only some embodiments of the present invention. Concrete prepared by using the preparation method of the present invention with other parameters such as agent type, dosage, temperature and time changed has similar properties.

[0065] In summary, the present invention can achieve a high lithium slag doping level while improving concrete's crack resistance and freeze-thaw resistance, and also has a certain carbon dioxide removal capacity. Compared with existing technologies, the present invention represents a significant improvement.

[0066] The above description is merely a representative embodiment of the present invention and does not constitute any form of limitation to the present invention. Any technical personnel familiar with the present invention who, without departing from the scope of the technical solution of the present invention, makes some changes or modifications to the embodiments disclosed above using the technical contents disclosed above are equivalent embodiments of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing concrete based on high-doped lithium slag, characterized in that: The following steps are involved: S1: obtaining lithium slag powder, and mixing the lithium slag powder with an activator, stirring evenly and then curing to obtain modified lithium slag; the activator is composed of an inorganic activator and an organic activator in a mass ratio of 2-4:1, the inorganic activator is any one or more of sodium sulfate, potassium sulfate, calcium sulfate, potassium phosphate, and calcium fluorosilicate, and the organic activator is triethanolamine and / or calcium lignin sulfonate; S2: mixing the modified lithium slag with cement, fine aggregate and coarse aggregate to obtain a mixture; S3: adding water to the mixture and continuously stirring until there is no segregation or bleeding, thereby obtaining the concrete; In step S1, the mass of the lithium slag powder is 30-50% of the mass of the cement, and the mass of the activator is 3-5% of the mass of the cement; in step S2, the mass ratio of the modified lithium slag to cement, fine aggregate and coarse aggregate is 0.33-0.55:1:1.5-2:2.5-3; in step S3, the mass of the water is 40-50% of the mass of the cement.

2. The method for preparing concrete based on highly doped lithium slag according to claim 1, characterized in that: In step S1, the particle size of the lithium slag powder is less than 0.075 mm and the specific surface area is 400-500 m 2 / kg, Li2O content is 2.5-3.5%, SiO2 content is 45-55%, and Al2O3 content is 15-20%.

3. The method for preparing concrete based on highly doped lithium slag according to claim 1, characterized in that: Step S1 also includes a step of drying the lithium slag powder, with the drying temperature being 100-120° C. and the drying time being 2-3 hours.

4. The method for preparing concrete based on highly doped lithium slag according to claim 1, characterized in that: In step S1, mechanical stirring is used for mixing, and the stirring speed is 100-300 r / min.

5. The method for preparing concrete based on highly doped lithium slag according to claim 1, characterized in that: In step S1, curing is performed at 80-100° C. for 24-36 hours.

6. A concrete based on highly doped lithium slag, characterized in that: The concrete is prepared by the method for preparing concrete based on high-doped lithium slag according to any one of claims 1 to 5.

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