Preparation process of coal gangue and carbon black composite conductive concrete material

Abstract

This invention discloses a preparation process for a composite conductive concrete material made of coal gangue and carbon black, comprising the following steps: (1) Tetraethyl orthosilicate and anhydrous ethanol are mixed to form a pretreatment solution. Carbon black powder is mixed with the pretreatment solution and then ultrasonically treated, and then allowed to stand. After completion, the solid product is separated to obtain the pretreated carbon black. (2) The pretreated carbon black is dispersed in water to form a dispersion, and an alkaline solution is added to adjust the dispersion to alkalinity, and then a heating reaction is carried out. After completion, the solid product is separated, dried, and ground to obtain modified carbon black powder. (3) The following raw materials are taken: silicate cement, coarse aggregate, conductive fine aggregate made of coal gangue, modified carbon black powder, fly ash cenospheres, water-reducing agent, and defoamer. The raw materials are mixed evenly and then water is added and stirred evenly to obtain the conductive concrete material. The process of this invention not only improves the conductivity of concrete, but also overcomes the problem of reduced concrete strength caused by the addition of carbon black.

Description

Technical Field

[0001] This invention relates to the field of conductive concrete preparation technology, specifically to a preparation process for a composite conductive concrete material made from coal gangue and carbon black. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Although ordinary concrete has some electrical conductivity, it is not a good conductor of electricity; its resistivity is generally around 10⁻⁶. 6 ~10 9 Between Ω·cm, it can reach 10 in the dry state. 13 With a strength of Ω·cm, it is considered a good insulator. Electrically Conductive Concrete (ECC) refers to a special building material with a certain degree of conductivity formed by adding a conductive phase to concrete. The addition of the conductive phase can greatly improve the conductivity of concrete, transforming it into a good conductor. It can be used not only for building floor heating and road de-icing and snow melting, but also for electromagnetic interference shielding, industrial anti-static measures, and grounding engineering for power equipment. Especially when used for heating and de-icing snow melting on roads such as airports and highways, it avoids the problems of concrete pavement erosion and accelerated freeze-thaw damage caused by traditional de-icing agents, compared to the traditional method of applying de-icing agents.

[0004] Currently, the conductive phases used in conductive concrete mainly include carbon fiber, graphene, and carbon black. Compared to other conductive phases, carbon black is more inexpensive. When dispersed in concrete, it forms a conductive network and conducts electricity through the tunneling effect, thereby improving the conductivity of the concrete. However, studies show that the amount of carbon black added is inversely proportional to the mechanical properties of the concrete. That is, to ensure conductivity, a certain proportion of carbon black is required, but this simultaneously leads to a deterioration in the mechanical strength of the concrete. Moreover, when the carbon black content reaches a certain proportion, the improvement in conductivity becomes less significant, and instead, a significant decrease in mechanical strength occurs. Summary of the Invention

[0005] This invention provides a preparation process for a composite conductive concrete material made from coal gangue and carbon black, which not only improves the conductivity of concrete but also effectively alleviates the problem of reduced concrete strength caused by the addition of carbon black. To achieve the above objectives, the technical solution of this invention is as follows.

[0006] A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Tetraethyl orthosilicate and anhydrous ethanol are mixed to form a pretreatment solution. Carbon black powder is mixed with the pretreatment solution and then subjected to ultrasonic treatment, followed by standing. After completion, the solid product is separated to obtain the pretreated carbon black.

[0007] (2) The pretreated carbon black is dispersed in water to form a dispersion, and an alkaline solution is added to adjust the dispersion to alkalinity. Then, the reaction is carried out by heating. After completion, the solid product is separated, dried, and ground to obtain modified carbon black powder.

[0008] (3) After mixing the carbonized coal gangue fine aggregate with the pretreatment liquid, let it stand, then separate the coal gangue fine aggregate, add it to water and add alkali solution to adjust the system to alkaline, and then carry out the heating reaction. After completion, the solid and liquid are separated, and after drying, the conductive coal gangue fine aggregate is obtained.

[0009] (4) Take the following raw materials: 30-50 parts by weight of silicate cement, 64-105 parts by weight of coarse aggregate, 42-60 parts by weight of conductive fine aggregate from coal gangue, 25-38 parts by weight of modified carbon black powder, 30-40 parts by weight of fly ash cenospheres, 0.5-1.2 parts by weight of water-reducing agent, and 0.1-0.3 parts by weight of defoamer. Mix all raw materials evenly, add water and stir evenly to obtain conductive concrete material.

[0010] Further, in step (1), the ratio of carbon black powder to pretreatment liquid is 1g:10~20ml. Optionally, the volume ratio of tetraethyl orthosilicate to anhydrous ethanol in the pretreatment liquid is 1~1.5:1.

[0011] Further, in step (1), the ultrasonic treatment time is 20-30 minutes. Optionally, the settling time is not less than 20 minutes.

[0012] Further, in step (2), the ratio of the pretreated carbon black to water is 1g: 20~40ml.

[0013] Further, in step (2), the dispersion is adjusted to pH 10-13 using the alkaline solution. Optionally, the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc.

[0014] Furthermore, in step (2), the heating temperature is 60~75℃ and the reaction time is 1.5~2 hours.

[0015] Furthermore, in step (2), the modified carbon black powder has a fineness of 300~400 mesh.

[0016] Further, in step (3), the method for carbonizing the coal gangue fine aggregate is as follows: the coal gangue fine aggregate is heated to 600~800℃ under a protective atmosphere for 1~2 hours. After completion, it is cooled to room temperature to obtain the final product. Optionally, the protective atmosphere includes any one of nitrogen, argon, etc.

[0017] Further, in step (3), the ratio of the coal gangue fine aggregate to the pretreatment liquid is 1g:10~20ml. Optionally, the settling time is not less than 20min.

[0018] Further, in step (3), the system is adjusted to pH 10-13 using the alkaline solution. Optionally, the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc.

[0019] Further, in step (3), the heating temperature is 60~75℃, and the reaction time is 1.5~2 hours. Optionally, the particle size of the conductive fine aggregate of coal gangue is continuously distributed between 0.2~1.0mm.

[0020] Further, in step (4), the fly ash cenospheres are prepared by the following method: fly ash cenospheres are mixed with a zinc source solution to form a wet material, dried, and then an alkaline solution is added and mixed evenly. The resulting mixture is calcined and then cooled to room temperature to obtain the final product.

[0021] Further, the ratio of the fly ash celery beads to the zinc source solution is 1g:1.5~2.5ml. Optionally, the zinc source solution has a mass fraction of 20~30%, and the zinc source includes at least one of zinc sulfate, zinc nitrate, zinc acetate, etc.

[0022] Furthermore, the OH- provided by the alkaline solution - With the Zn provided by the zinc source solution 2+ The molar ratio is 2.1~2.3:1. Optionally, the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc.

[0023] Furthermore, the calcination treatment is carried out at a temperature of 300~400℃ for a time of 40~60 minutes.

[0024] Compared with the prior art, the present invention has at least the following beneficial technical effects: (1) In this invention, carbon black powder adsorbed with tetraethyl orthosilicate is dispersed in an alkaline environment and heated to react, causing the tetraethyl orthosilicate in the carbon black powder to hydrolyze under the catalysis of the alkaline environment to form nano-SiO2, thereby forming modified carbon black powder containing nano-SiO2. This highly active nano-SiO2 allows the modified carbon black powder to be distributed in concrete materials. During the cement hydration stage, the hydration product calcium hydroxide can be used for a secondary hydration reaction to form conductive hydrated calcium silicate doped with carbon black. On the one hand, this cementitious substance allows the carbon black particles to bond more tightly with the concrete matrix, overcoming the problem of deterioration in the mechanical strength of concrete materials caused by the addition of carbon black. On the other hand, the conductive hydrated calcium silicate dispersed in the concrete material forms a conductive network, improving the conductivity of the concrete.

[0025] (2) This invention uses coal gangue as fine aggregate, which is carbonized and then absorbs tetraethyl orthosilicate, followed by heating and reaction in an alkaline environment. In this process, the high organic content of coal gangue is utilized. After carbonization, the organic matter is converted into carbonaceous material, which acts as a conductive material distributed within the fine aggregate, making it conductive. This conductive material, together with the modified carbon black powder, forms a conductive network system in the concrete, effectively increasing the conductivity of the concrete material and overcoming the problem that the improvement in conductivity becomes less significant when the carbon black content reaches a certain proportion. Simultaneously, the alkaline environment also activates the fine aggregate, causing the inert silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra on the surface of the coal gangue to depolymerize and form an active surface. This surface can react with calcium hydroxide, a cement hydration product, to form hydrated calcium silicate, hydrated calcium aluminate, and other cementitious components, thereby improving the strength of the concrete material. Furthermore, this invention utilizes the adsorption properties of carbonaceous material formed in the fine aggregate of coal gangue after carbonization treatment to adsorb tetraethyl orthosilicate and convert it into nano-SiO2. The conductive carbonaceous material containing SiO2 in the fine aggregate of coal gangue reacts with calcium hydroxide, a cement hydration product, to form carbon-doped calcium silicate hydrate. This not only improves the bonding force between the fine aggregate of coal gangue and the concrete matrix, thereby increasing the strength of the concrete, but also enhances the electrical conductivity between the aggregate and the concrete matrix, thus improving the conductivity of the concrete.

[0026] (3) The conductive concrete of the present invention also incorporates modified fly ash cenospheres. First, zinc hydroxide is formed on the surface of the fly ash cenospheres using an alkaline solution. Simultaneously, the aluminum-oxygen tetrahedra on the surface of the fly ash cenospheres depolymerize under the action of the alkaline solution, releasing aluminum ions to form aluminum hydroxide, which is then incorporated into the zinc hydroxide. When the zinc hydroxide is calcined and converted into aluminum-doped zinc oxide, the aluminum-doped zinc oxide becomes a good conductive phase, thereby converting the fly ash cenospheres into a conductive material. This not only improves the conductivity of the concrete material but also enhances the heat storage capacity of the concrete by utilizing the good thermal insulation properties of the fly ash cenospheres. After the conductive concrete has finished heating up, it can maintain a heating state for a longer period of time to continue de-icing and snow melting. Attached Figure Description

[0027] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation thereof. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings.

[0028] Figure 1 The following is a diagram of the compressive strength test in Example 1.

[0029] Figure 2 The following is a test diagram of the conductor performance in Example 1. Detailed Implementation

[0030] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. The preferred embodiments and materials described herein are for demonstration purposes only. It should be noted that all technical and scientific terms used herein have the same meaning as those skilled in the art, unless otherwise defined.

[0031] In addition, the reagents or raw materials used in this invention can be purchased through conventional channels. Unless otherwise specified, the reagents or raw materials used in this invention shall be used in accordance with conventional methods in the field or in accordance with the product instructions.

[0032] Example 1 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Tetraethyl orthosilicate and anhydrous ethanol were mixed at a ratio of 1.5:1 (v / v) and stirred until homogeneous to form a pretreatment solution. Carbon black powder was mixed with the pretreatment solution at a ratio of 1g:10ml and ultrasonically treated for 20min, then allowed to stand for 25min. After completion, the solid product was separated by filtration to obtain pretreated carbon black.

[0033] (2) The pretreated carbon black was dispersed in water at a material-to-liquid ratio of 1g:40ml and stirred to form a dispersion. Then, sodium hydroxide solution was added to adjust the pH of the dispersion to 12, and then the mixture was heated to 70°C and kept at that temperature for 2 hours. After completion, the solid product was filtered to separate it, dried at 80°C to constant weight, and then ground to obtain 400-mesh modified carbon black powder.

[0034] (3) Coal gangue fine aggregate with a continuous particle size distribution between 0.2 and 1.0 mm was heated to 680°C at a rate of 10°C / min and held for 1 hour in a nitrogen atmosphere for carbonization treatment. After completion, it was cooled to room temperature. Then, the carbonized coal gangue fine aggregate was mixed with the pretreatment liquid of step (1) at a ratio of 1g:15ml and stirred evenly. After standing for 30 minutes, the coal gangue fine aggregate was filtered out and added to clean water. Then, sodium hydroxide solution was added to adjust the pH of the system to 12, and then heated to 70°C for 2 hours. After completion, the solid product was filtered out and dried at 70°C for 1.5 hours to obtain conductive coal gangue fine aggregate.

[0035] (4) Take the following raw materials: 40 parts by weight of 42.5 ordinary Portland cement, 90 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 60 parts by weight of conductive fine aggregate of coal gangue as described in this embodiment, 35 parts by weight of modified carbon black powder as described in this embodiment, 32 parts by weight of fly ash cenospheres, 0.8 parts by weight of polycarboxylate superplasticizer, and 0.2 parts by weight of organosilicon defoamer. Mix all raw materials evenly, add 32.5 parts by weight of water, and then stir evenly to obtain conductive concrete material.

[0036] Performance testing: (1) The 28-day compressive strength of the conductive concrete material prepared in this embodiment was tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081-2019). Figure 1 (as shown). (2) The resistivity of the conductive concrete material prepared in this embodiment was tested using the four-electrode method (as shown). Figure 2 (As shown). Specifically: the test voltage U is set to 10V, and the concrete resistivity is calculated according to the following formula: ρ=US / IL, where: U is the test voltage, I is the detected current, S is the contact area between the electrode and the concrete specimen, and L is the vertical distance between the two electrodes connected to the voltmeter. The results are shown in the table below.

[0037]

[0038] Example 2 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Tetraethyl orthosilicate and anhydrous ethanol were mixed at a ratio of 1:1 (v / v) and stirred until homogeneous to form a pretreatment solution. Carbon black powder was mixed with the pretreatment solution at a ratio of 1g:15ml and ultrasonically treated for 30min, then allowed to stand for 20min. After completion, the solid product was separated by filtration to obtain pretreated carbon black.

[0039] (2) The pretreated carbon black was dispersed in water at a material-to-liquid ratio of 1g:30ml and stirred to form a dispersion. Then, ammonia was added to adjust the pH of the dispersion to 10, and then the mixture was heated to 60°C and kept at that temperature for 2 hours. After completion, the solid product was filtered to separate it, dried at 80°C to constant weight, and then ground to obtain 350-mesh modified carbon black powder.

[0040] (3) Coal gangue fine aggregate with a continuous particle size distribution between 0.2 and 1.0 mm was heated to 600°C at a rate of 10°C / min and held for 2 hours in a nitrogen atmosphere for carbonization treatment. After completion, it was cooled to room temperature. Then, the carbonized coal gangue fine aggregate was mixed with the pretreatment liquid of step (1) at a ratio of 1g:20ml and stirred evenly. After standing for 30 minutes, the coal gangue fine aggregate was filtered out and added to clean water. Then, ammonia water was added to adjust the pH of the system to 10, and then the mixture was heated to 70°C and reacted for 2 hours. After completion, the solid product was filtered out and dried at 60°C for 2 hours to obtain conductive coal gangue fine aggregate.

[0041] (4) Mix fly ash cenospheres with a 20% zinc sulfate solution at a ratio of 1g:2.5ml to form a wet material. After drying, add sodium hydroxide solution and mix thoroughly. The sodium hydroxide solution provides OH- - With the Zn provided by zinc sulfate solution 2+ The molar ratio is 2.1:1. After completion, the resulting mixture is first dried to remove moisture, and then heated to 300℃ at a heating rate of 10℃ / min and held for 60min for calcination treatment. After completion, it is cooled to room temperature to obtain modified fly ash cenospheres.

[0042] (5) Take the following raw materials: 30 parts by weight of 42.5 ordinary Portland cement, 64 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 42 parts by weight of conductive fine aggregate of coal gangue as described in this embodiment, 25 parts by weight of modified carbon black powder as described in this embodiment, 30 parts by weight of modified fly ash cenospheres as described in this embodiment, 0.5 parts by weight of polycarboxylate superplasticizer, and 0.1 parts by weight of organosilicon defoamer. Mix all raw materials evenly, add 27 parts by weight of water, and then stir evenly to obtain conductive concrete material.

[0043] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0044]

[0045] Example 3 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Tetraethyl orthosilicate and anhydrous ethanol were mixed at a ratio of 1.3:1 (v / v) and stirred until homogeneous to form a pretreatment solution. Carbon black powder was mixed with the pretreatment solution at a ratio of 1g:20ml and ultrasonically treated for 30min, then allowed to stand for 25min. After completion, the solid product was separated by filtration to obtain pretreated carbon black.

[0046] (2) The pretreated carbon black was dispersed in water at a material-to-liquid ratio of 1g:20ml and stirred to form a dispersion. Then, sodium hydroxide solution was added to adjust the pH of the dispersion to 13, and then heated to 75°C and kept at that temperature for 1.5 hours. After completion, the solid product was filtered to separate it, dried at 80°C to constant weight, and then ground to obtain 300-mesh modified carbon black powder.

[0047] (3) Coal gangue fine aggregate with a continuous particle size distribution between 0.2 and 1.0 mm was heated to 800°C at a rate of 10°C / min and held for 1.5 hours in a nitrogen atmosphere for carbonization treatment. After completion, it was cooled to room temperature. Then, the carbonized coal gangue fine aggregate was mixed with the pretreatment liquid of step (1) at a ratio of 1g:10ml and stirred evenly. After standing for 20 minutes, the coal gangue fine aggregate was filtered out and added to clean water. Then, sodium hydroxide solution was added to adjust the pH of the system to 13, and then heated to 75°C for 1.5 hours. After completion, the solid product was filtered out and dried at 60°C for 2 hours to obtain conductive coal gangue fine aggregate.

[0048] (4) Mix fly ash cenospheres with a 30% zinc nitrate solution at a ratio of 1g:1.5ml to form a wet material. After drying, add ammonia water and mix thoroughly. The ammonia water provides OH- - With the Zn provided by the zinc nitrate solution 2+ The molar ratio is 2.3:1. After completion, the resulting mixture is first dried to remove moisture, and then heated to 400℃ at a heating rate of 10℃ / min and held at that temperature for 40min for calcination treatment. After completion, it is cooled to room temperature to obtain modified fly ash cenospheres.

[0049] (5) Take the following raw materials: 50 parts by weight of 42.5 ordinary Portland cement, 105 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 55 parts by weight of conductive fine aggregate of coal gangue as described in this embodiment, 38 parts by weight of modified carbon black powder as described in this embodiment, 40 parts by weight of modified fly ash cenospheres as described in this embodiment, 1.2 parts by weight of polycarboxylate superplasticizer, and 0.3 parts by weight of organosilicon defoamer. Mix all raw materials evenly, add 41 parts by weight of water, and then stir evenly to obtain conductive concrete material.

[0050] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0051]

[0052] Example 4 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Take the following raw materials: 40 parts by weight of 42.5 ordinary silicate cement, 90 parts by weight of coarse aggregate with a particle size of 5-7 mm, 60 parts by weight of fine aggregate of coal gangue with a particle size of 0.2-1.0 mm, 35 parts by weight of 400 mesh carbon black, 32 parts by weight of fly ash cenospheres, 0.8 parts by weight of polycarboxylate superplasticizer, and 0.2 parts by weight of organosilicon defoamer.

[0053] (2) After mixing all the raw materials evenly, add 32.5 parts by weight of water and stir evenly to obtain conductive concrete material.

[0054] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0055]

[0056] Example 5 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Take the following raw materials: 40 parts by weight of 42.5 ordinary silicate cement, 90 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 60 parts by weight of conductive fine aggregate of coal gangue prepared in Example 1 above, 35 parts by weight of 400 mesh carbon black powder, 32 parts by weight of fly ash cenospheres, 0.8 parts by weight of polycarboxylate superplasticizer, and 0.2 parts by weight of organosilicon defoamer.

[0057] (2) After mixing all the raw materials evenly, add 32.5 parts by weight of water and stir evenly to obtain conductive concrete material.

[0058] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0059]

[0060] Example 6 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Coal gangue fine aggregate with a continuous particle size between 0.2 and 1.0 mm was mixed with the pretreatment liquid from step (1) of Example 2 at a ratio of 1 g: 20 ml and stirred evenly. After standing for 30 min, the coal gangue fine aggregate was filtered out and added to clean water. Then, ammonia water was added to adjust the pH of the system to 10, and then the mixture was heated to 70°C and reacted for 2 hours. After completion, the solid product was filtered out and dried at 60°C for 2 hours to obtain conductive coal gangue fine aggregate.

[0061] (2) Take the following raw materials: 30 parts by weight of 42.5 ordinary silicate cement, 64 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 42 parts by weight of conductive fine aggregate of coal gangue as described in this embodiment, 25 parts by weight of modified carbon black powder prepared in Example 2 above, 30 parts by weight of modified fly ash cenospheres prepared in Example 2 above, 0.5 parts by weight of polycarboxylate superplasticizer, and 0.1 parts by weight of organosilicon defoamer. Mix all raw materials evenly, add 27 parts by weight of water, and then stir evenly to obtain conductive concrete material.

[0062] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0063]

[0064] Example 7 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Take the following raw materials: 40 parts by weight of 42.5 ordinary Portland cement, 90 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 60 parts by weight of fine aggregate of coal gangue with a particle size between 0.2 and 1.0 mm, 35 parts by weight of modified carbon black powder prepared in Example 1 above, 32 parts by weight of fly ash cenospheres, 0.8 parts by weight of polycarboxylate superplasticizer, and 0.2 parts by weight of organosilicon defoamer. Mix all raw materials evenly, add 32.5 parts by weight of water, and then stir evenly to obtain conductive concrete material.

[0065] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0066]

[0067] Example 8 A preparation process for a composite conductive concrete material made from coal gangue and carbon black includes the following steps: (1) Coal gangue fine aggregate with a particle size continuously distributed between 0.2 and 1.0 mm is heated to 800℃ in a nitrogen atmosphere at a rate of 10℃ / min and held for 1.5 hours for carbonization treatment. After completion, it is cooled to room temperature to obtain carbonized coal gangue fine aggregate.

[0068] (2) Take the following raw materials: 50 parts by weight of 42.5 ordinary silicate cement, 105 parts by weight of coarse aggregate with a particle size between 5 and 7 mm, 55 parts by weight of fine aggregate of carbonized coal gangue as described in this embodiment, 38 parts by weight of modified carbon black powder prepared in Example 3, 40 parts by weight of modified fly ash cenospheres prepared in Example 3, 1.2 parts by weight of polycarboxylate superplasticizer, and 0.3 parts by weight of organosilicon defoamer. Mix all raw materials evenly, add 41 parts by weight of water, and then stir evenly to obtain conductive concrete material.

[0069] Performance testing: The 28-day compressive strength and resistivity of the conductive concrete material prepared in this embodiment were tested using the same method as in Example 1. The results are shown in the table below.

[0070]

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for the preparation of coal gangue and carbon black composite conductive concrete material, characterized in that, Includes the following steps: (1) Tetraethyl orthosilicate and anhydrous ethanol are mixed to form a pretreatment solution. Carbon black powder is mixed with the pretreatment solution and then ultrasonically treated, and then allowed to stand. After completion, the solid product is separated to obtain the pretreated carbon black. (2) Disperse the pretreated carbon black in water to form a dispersion, add alkaline solution to adjust the dispersion to alkalinity, and then heat the reaction; after completion, separate the solid product, dry it and grind it to obtain modified carbon black powder. (3) After the carbonized coal gangue fine aggregate is mixed with the pretreatment liquid, it is allowed to stand. Then the coal gangue fine aggregate is separated, added to water and alkaline solution to adjust the system to alkaline, and then heated to react. After the solid-liquid separation is completed, the conductive coal gangue fine aggregate is obtained after drying. (4) Take the following raw materials: 30-50 parts by weight of silicate cement, 64-105 parts by weight of coarse aggregate, 42-60 parts by weight of conductive fine aggregate of coal gangue, 25-38 parts by weight of modified carbon black powder, 30-40 parts by weight of fly ash cenospheres, 0.5-1.2 parts by weight of water-reducing agent, and 0.1-0.3 parts by weight of defoamer; mix the raw materials evenly and then add water and stir evenly to obtain conductive concrete material.

2. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (1), the ratio of carbon black powder to pretreatment liquid is 1g:10~20ml.

3. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (1), the volume ratio of tetraethyl orthosilicate to anhydrous ethanol in the pretreatment solution is 1~1.5:

1.

4. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (1), the ultrasonic treatment time is 20~30 min.

5. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (1), the settling time shall not be less than 20 minutes.

6. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (2), the ratio of pretreated carbon black to water is 1g: 20~40ml.

7. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (2), the dispersion is adjusted to pH 10-13 using the alkaline solution.

8. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (2), the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.

9. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (2), the heating temperature is 60~75℃ and the reaction time is 1.5~2 hours.

10. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (2), the modified carbon black powder has a fineness of 300~400 mesh.

11. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the carbonization treatment of coal gangue fine aggregate is as follows: the coal gangue fine aggregate is heated to 600~800℃ under a protective atmosphere for 1~2 hours; after completion, it is cooled to room temperature to obtain the final product.

12. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the settling time shall not be less than 20 minutes.

13. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the ratio of fine coal gangue aggregate to pretreatment liquid is 1g:10~20ml.

14. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the system is adjusted to pH 10-13 using the alkaline solution.

15. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.

16. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the heating temperature is 60~75℃ and the reaction time is 1.5~2 hours.

17. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 1, characterized in that, In step (3), the particle size of the conductive fine aggregate of coal gangue is continuously distributed between 0.2 and 1.0 mm.

18. The preparation process of the coal gangue and carbon black composite conductive concrete material according to any one of claims 1-17, characterized in that, In step (4), the fly ash cenospheres are prepared by the following method: fly ash cenospheres are mixed with zinc source solution to form a wet material, dried and then mixed with alkali solution; the resulting mixture is calcined and then cooled to room temperature to obtain the final product.

19. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 18, characterized in that, The ratio of fly ash cenospheres to zinc source solution is 1g:1.5~2.5ml.

20. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 18, characterized in that, The zinc source includes at least one of zinc sulfate, zinc nitrate, and zinc acetate.

21. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 18, characterized in that, The OH provided by the alkaline solution - With the Zn provided by the zinc source solution 2+ The molar ratio is 2.1~2.3:

1.

22. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 18, characterized in that, The alkaline solution includes at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.

23. The preparation process of the coal gangue and carbon black composite conductive concrete material according to claim 18, characterized in that, The calcination treatment is carried out at a temperature of 300~400℃ for a time of 40~60 minutes.

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