Concrete based on high-doping-amount lithium slag and preparation method thereof

Abstract

The invention discloses concrete based on high-doping-amount lithium slag and a preparation method of the concrete, and belongs to the technical field of concrete. The preparation method comprises the following steps: S1, obtaining lithium slag micro-powder, mixing the lithium slag micro-powder with an exciting agent, uniformly stirring, and maintaining to obtain modified lithium slag; s2, mixing the modified lithium slag with cement, fine aggregate and coarse aggregate to obtain a mixture; and S3, adding water into the mixture, and continuously stirring until no segregation or bleeding phenomenon exists, so as to obtain the concrete. According to the present invention, the high doping amount of the lithium slag can be achieved while the crack resistance and the freeze-thaw resistance of the concrete can be improved so as to prolong the service life of the highway subgrade and promote the technical progress and the sustainable development of the highway construction industry; in addition, the automobile exhaust gas purifying agent also has a certain carbon dioxide removal capability, has a certain contribution to reduction of carbon dioxide in automobile exhaust gas emission, and is beneficial to relieving 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 the rapid economic development and the acceleration of urbanization, the scale of highway construction has continued to expand, and the demand for roadbed materials has also increased. Traditional roadbed materials mainly rely on natural sand and gravel, which not only leads to huge resource consumption, but also causes costs to continue to rise. Conventional roadbed concrete has also exposed many problems in practical applications, such as easy cracking and insufficient freeze-thaw resistance, which seriously affect the durability and service life of the highway. In addition, a large amount of industrial solid waste, such as fly ash, slag, etc., especially lithium slag (waste residue after lithium salt refining), has low utilization rate and large amounts of accumulation, causing serious pollution to the environment.

[0003] In the prior art, although there have been some attempts to apply industrial solid waste to the research and practice of roadbed materials, the slag content is usually less than 20%. Too high a slag content will affect the bearing capacity, permeability and stability of the roadbed materials. As for lithium slag, due to its complex composition, containing lithium, silicon, aluminum and other elements, current research mainly focuses on the chemical lithium extraction process of lithium slag and its application in other fields, such as soil conditioner, etc., and it has not yet been used on a large scale 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 solution of the present invention is as follows: In one aspect, a method for preparing concrete based on high-doped lithium slag is provided, comprising the following steps: S1: obtaining lithium slag powder, 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 or bleeding, thereby obtaining the concrete.

[0006] 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,Li 2 O content is 2.5-3.5%, SiO 2 The content is 45-55%, Al 2 O 3 The content is 15-20%.

[0007] Preferably, step S1 further comprises a step of drying the lithium slag powder, the drying temperature is 100-120° C., and the drying time is 2-3 hours.

[0008] Preferably, in step S1, mechanical stirring is used for mixing, and the stirring speed is 100-300 r / min.

[0009] Preferably, in step S1, the curing is performed at 80-100° C. for 24-36 hours.

[0010] Preferably, in step S1, the mass of the lithium slag powder is 30-50% of the mass of cement, and the mass of the activator is 3-5% of the mass of 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 cement.

[0011] Preferably, in step S1, the activator is composed of an inorganic activator and an organic activator in a mass ratio of 2-4:1.

[0012] Preferably, the inorganic activator is any one or more of sodium sulfate, potassium sulfate, calcium sulfate, potassium phosphate, and calcium fluorosilicate.

[0013] Preferably, the organic activator is triethanolamine and / or calcium lignin sulfonate.

[0014] On the other hand, there is also provided a concrete based on high-doped lithium slag, which is prepared by any of the above-mentioned methods for preparing concrete based on high-doped lithium slag.

[0015] The beneficial effects of the present invention are: 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 the pollution to the environment, and reduces the dependence on natural resources, which meets the requirements of sustainable development; the present invention can improve the crack resistance and freeze-thaw resistance of concrete while realizing the high-doping amount of lithium slag, thereby extending the service life of the highway roadbed and promoting the technological progress and sustainable development of 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

[0016] The present invention is further described below in conjunction with 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 generally 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 disclosure of the present invention 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.

[0017] In one aspect, the present invention provides a method for preparing concrete based on high-doped lithium slag, comprising the following steps: S1: obtaining lithium slag powder, mixing the lithium slag powder with an activator, stirring evenly and then curing to obtain modified lithium slag.

[0018] 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,Li 2 O content is 2.5-3.5%, SiO 2 The content is 45-55%, Al 2 O 3 The content is 15-20%.

[0019] In a specific embodiment, 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. In this embodiment, by drying the lithium slag powder, the excess water in the lithium slag powder can be removed to prevent the water-cement ratio of the concrete from being affected in the subsequent concrete preparation process; in addition, it can also improve the excitation effect of the active ingredients of the lithium slag powder, so as to more effectively participate in the cement hydration reaction, generate more hydration products, and improve the performance of the concrete.

[0020] In a specific embodiment, the mixing is performed by mechanical stirring at a stirring speed of 100-300 r / min.

[0021] In a specific embodiment, the curing is performed at 80-100° C. for 24-36 hours.

[0022] In a specific embodiment, the stimulator is composed of an inorganic stimulator and an organic stimulator in a mass ratio of 2-4: 1. Optionally, the inorganic stimulator is any one or more of sodium sulfate, potassium sulfate, calcium sulfate, potassium phosphate, and calcium fluorosilicate, and the organic stimulator is triethanolamine and / or calcium lignin sulfonate.

[0023] S2: Mixing the modified lithium slag with cement, fine aggregate and coarse aggregate to obtain a mixture.

[0024] It should be noted that the fine aggregate and coarse aggregate in concrete are prior art, and the specific components will not be described here.

[0025] S3: adding water to the mixture and continuously stirring until there is no segregation or bleeding, thereby obtaining the concrete.

[0026] In a specific embodiment, in step S1, the mass of the lithium slag powder is 30-50% of the mass of cement, and the mass of the activator is 3-5% of the mass of 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 cement.

[0027] In the present invention, after the lithium slag powder is modified by the activator, its active ingredients are fully activated, and a secondary hydration reaction occurs with the cement hydration product to generate a large number of stable hydration products, such as hydrated calcium silicate and hydrated calcium aluminate, etc. 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 tensile 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 erosion environments, and thus improves the freeze-thaw resistance and durability.

[0028] In addition, lithium slag also contains alkaline oxides (such as CaO, MgO, etc.), which can react chemically with carbon dioxide to form carbonate compounds. For example, CaO and CO 2 The reaction produces CaCO 3 This chemical reaction process of absorbing carbon dioxide can reduce the amount of carbon dioxide emissions in automobile exhaust to a certain extent.

[0029] On the other hand, the present invention further provides a concrete based on high-doped lithium slag, which is prepared by any of the above-mentioned methods for preparing concrete based on high-doped lithium slag.

[0030] Example 1 A concrete based on high-doped lithium slag is prepared by the following steps: (1) obtaining lithium slag powder and drying the lithium slag powder; 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,Li 2 O content is 3%, SiO2 The content is 50%, Al 2 O 3 The content is 18%. The drying temperature is 110°C and the time is 2.5 hours.

[0031] (2) mixing the lithium slag powder and the activator, stirring them evenly and then curing them to obtain modified lithium slag; In this embodiment, the amount of the lithium slag powder is 190 kg, the amount of the activator is 15.3 kg, and 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 the inorganic activator to the organic activator is 2:1). When mixing, the lithium slag powder and the activator are added to the mixer, stirred at a speed of 200 r / min for 15 minutes; then placed in a constant temperature curing box, cured at 90°C for 24 hours, to obtain the modified lithium slag.

[0032] (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 into a mixer and mixed, and dry mixed for 45 seconds to obtain a mixture.

[0033] (4) 171 kg of water was added to the mixer and stirring was continued for 150 s. At this time, there was no segregation or water bleeding, and the concrete was obtained.

[0034] Example 2 Different from Example 1, the activator in step (2) of this example is composed of 4.4 kg of sodium sulfate, 7 kg of potassium phosphate and 3.8 kg of calcium lignin sulfonate (ie, the mass ratio of the inorganic activator to the organic activator is 3:1).

[0035] Example 3 Different from Example 1, the amount of lithium slag powder used in step (2) of this example is 114 kg (i.e., the mass of lithium slag powder is 30% of the mass of cement), and the amount of activator used is 11.4 kg (i.e., the mass of activator is 3% of the mass of cement).

[0036] Example 4 Different from Example 1, the curing temperature in step (2) of this example is 100°C.

[0037] Example 5 Different from Example 1, the activator in step (2) of this embodiment is composed 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.

[0038] Comparative Example 1 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.

[0039] Comparative Example 2 Different from Example 1, the activator in step (2) of this example consists of only 15.3 kg of triethanolamine.

[0040] Comparative Example 3 Different from Example 1, the activator in step (3) of this example is composed of 3.1 kg of calcium hydroxide, 7.1 kg of aluminum sulfate 18hydrate and 5.1 kg of triethanolamine.

[0041] Comparative Example 4 Different from Example 1, the stimulator in step (2) of this example is composed of 3.1 kg of sodium sulfate, 7.1 kg of potassium sulfate and 5.1 kg of coconut oil diethanolamide.

[0042] 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 distance between the 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 and smooth without obvious defects); then cure for 7 days at room temperature (20-25°C). During the curing period, watering is used to keep the concrete surface moist. The number of watering times per day is determined according to weather conditions, generally 3-4 times. The finished product is subjected to performance testing, and the test results are shown in Table 1: Table 1 Performance test results of concrete in various embodiments and comparative examples

[0043] As can be seen from Table 1, the concrete based on high-doped lithium slag of the present invention can have excellent compressive strength, carbon dioxide removal rate, flexural tensile strength, freeze-thaw resistance and chloride ion permeability resistance on the basis of high-doped lithium slag, and can meet the application requirements of highway subgrade. Concrete made by using only inorganic activators, only organic activators and composite activators mixed with organic and inorganic agents not specified in the present invention cannot achieve the excellent effect that the present invention can achieve.

[0044] It should be noted that the above embodiments are only some embodiments of the present invention, and other concretes prepared by changing the type of reagent, dosage, temperature and time and adopting the preparation method of the present invention have similar properties.

[0045] In summary, the present invention can achieve a high doping amount of lithium slag while improving the crack resistance and freeze-thaw resistance of concrete; and can have a certain carbon dioxide removal capacity. Compared with the prior art, the present invention has significant progress.

[0046] The above description is only a representative embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, uses the above-disclosed technical contents to make some changes or modifications to the embodiments are equivalent embodiments of the present invention. However, any simple modification, 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, 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 or bleeding, thereby obtaining the concrete.

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

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

6. The method for preparing concrete based on high-doped lithium slag according to claim 1, characterized in that: In step S1, the mass of the lithium slag powder is 30-50% of the mass of cement, and the mass of the activator is 3-5% of the mass of 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 cement.

7. The method for preparing concrete based on high-doped lithium slag according to any one of claims 1 to 6, characterized in that: In step S1, the activator is composed of an inorganic activator and an organic activator in a mass ratio of 2-4:

1.

8. The method for preparing concrete based on high-doped lithium slag according to claim 7, characterized in that: The inorganic activator is any one or more of sodium sulfate, potassium sulfate, calcium sulfate, potassium phosphate, and calcium fluorosilicate.

9. The method for preparing concrete based on high-doped lithium slag according to claim 7, characterized in that: The organic activator is triethanolamine and / or calcium lignin sulfonate.

10. 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 as described in any one of claims 1 to 9.

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