A method for increasing the activity of a concrete mineral admixture

Abstract

This invention relates to a method for enhancing the activity of mineral admixtures in concrete, belonging to the field of building materials technology. It aims to solve the technical problem that while traditional mechanical grinding can improve the fineness of admixtures, it has limited impact on the vitreous structure, resulting in insufficient activity enhancement. This invention provides a method for enhancing the activity of mineral admixtures in concrete, comprising the following steps: raw material pretreatment: crushing and drying the mineral admixtures; plasma-assisted grinding: feeding the dried mineral admixtures into a plasma mill for mechanical grinding followed by plasma treatment; and then natural cooling to room temperature. The plasma-treated samples are finer and have a more porous microstructure; the 28-day activity index is 15%-30% higher than that of traditional grinding; the synergistic effect of plasma and mechanical force reduces energy consumption; the industrial waste residue has higher activity, allowing for a larger dosage in concrete and a more significant reduction in CO2 emissions.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology and relates to a method for improving the activity of mineral admixtures in concrete. Background Technology

[0002] Mineral admixtures, as a major component of cement concrete, contribute positively to the fluidity, strength, and durability of concrete. Currently, the main mineral admixtures used in engineering, including water-quenched blast furnace slag and fly ash, are primarily composed of vitreous structures rich in SiO2 and Al2O3 as their main active ingredients. Mechanical grinding is often required to meet their activity requirements. While traditional mechanical grinding can improve the fineness of the admixtures, it has limited impact on the vitreous structure, resulting in insufficient activity enhancement. Plasma, with its high energy density and high energy conversion efficiency, can break the Si-O and Al-O bonds in mineral admixtures and generate active sites. This patent utilizes plasma treatment to treat silicon-aluminum mineral admixtures, altering their composition and structure to enhance their activity, further contributing to the low-carbon development of concrete. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method for improving the activity of concrete mineral admixtures.

[0004] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for improving the activity of mineral admixtures in concrete, comprising the following steps: S1: Raw material pretreatment: Crush and dry the mineral admixture raw materials to a moisture content of <1%; S2: Plasma-assisted grinding: The pretreated mineral admixture is fed into a plasma mill for mechanical grinding, and the plasma generator is started to treat the powder with plasma. The plasma generator uses low-temperature plasma. S3: Post-processing: Allow to cool naturally to room temperature after shutdown; Preferably, in step S1, the mineral admixture raw material is crushed to a particle size ≤ 5 mm; Preferably, in step S2, the plasma mill is a ball mill with a built-in plasma generator, and the plasma generator includes a dielectric barrier discharge device or an arc discharge device. Preferably, in step S2, the power of the plasma generator is 50-500kW, the frequency is 1-100kHz, the working gas is air, and the discharge mode is continuous discharge. Preferably, in step S2, the pretreated mineral admixture is first fed into a plasma mill for mechanical grinding for 10 to 30 minutes, and then the plasma control power supply is started for plasma treatment for 2 to 10 minutes. Preferably, in step S2, the mineral admixture is subjected to plasma treatment simultaneously during the mechanical grinding process.

[0005] The beneficial effects of this invention are as follows: This invention proposes a synergistic method integrating plasma excitation and mechanical grinding, which simultaneously achieves ultrafine grinding and plasma activation of mineral admixtures within a plasma mill. The plasma-treated samples are finer, have a more porous microstructure, and exhibit significantly enhanced hydration activity. Specific advantages are as follows: 1. Phase change: Taking water-quenched blast furnace slag as an example, the phase changes significantly before and after plasma treatment. When comparing the slag powder after 5 minutes of plasma treatment with the untreated slag powder, the plasma-treated sample is finer and has a looser microstructure.

[0006] 2. Enhanced activity: The activity index of plasma-treated slag powder reaches over 85% after 7 days, and the activity index after 28 days is 15%-30% higher than that of traditional grinding (GB / T 18046-2017).

[0007] 3. Energy-saving and efficient: The synergistic effect of plasma and mechanical force reduces energy consumption by more than 20%.

[0008] 4. Environmental friendliness: Industrial waste residue has higher activity, allowing for greater dosage in concrete and more significant reduction in CO2 emissions.

[0009] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0010] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 Scanning electron microscope (SEM) images of slag powder: (a) is an SEM image of untreated slag powder, and (b) is an SEM image of slag powder treated with plasma for 5 minutes. Detailed Implementation

[0011] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0012] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0013] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0014] Example 1 1. Raw material pretreatment: Dry the granulated blast furnace slag to a moisture content of <1%.

[0015] 2. Plasma Mill: Low-temperature plasma is released by embedding a plasma generator (such as a dielectric barrier discharge or arc discharge device) within the ball mill. The plasma parameters are as follows: Power: 300kW, Frequency: 100kHz; Working gas: air; Discharge mode: Continuous discharge 3. Plasma-assisted grinding (1) The dried slag powder is fed into a plasma mill and mechanically ground for 15 minutes. (2) Start the plasma control power supply so that the powder is treated with plasma for 6 minutes during the mechanical grinding process.

[0016] 4. Post-processing: After shutdown, allow the machine to cool naturally to room temperature to prevent thermal stress from causing powder agglomeration.

[0017] Comparative Example 1 The slag powder treated by plasma according to this invention and the traditional mechanical grinding were compared. The slag powder was replaced with cement at a dosage of 30% according to the method of GB / T 18046-2017. The specific surface area and activity index were tested. It is obvious that the plasma-treated slag powder has higher activity.

[0018] Sample source Specific surface area (m² / kg) 7d activity index (%) 28d activity index (%) Traditional slag powder grinding time: 15 minutes 382 78 94 This invention (mechanical grinding for 15 minutes, followed by simultaneous plasma treatment for 6 minutes). 535 88 110 Example 2 Performance Comparison Test 1. Raw material pretreatment: Crush the tuff particles to 3mm and dry them in an oven at 105℃±5℃ until the moisture content is <0.5%.

[0019] 2. Plasma Mill: Low-temperature plasma is released by embedding a plasma generator (such as a dielectric barrier discharge or arc discharge device) within the ball mill. The plasma parameters are as follows: Power: 300kW, Frequency: 100kHz; Working gas: air; Discharge mode: Continuous discharge 3. Plasma-assisted grinding (1) The dried tuff particles are fed into a plasma mill and mechanically ground for 20 minutes. (2) Turn on the plasma control power supply to treat the powder with plasma for 10 minutes during the mechanical grinding process, and then let it cool naturally to room temperature. Take out a portion of the sample for testing. (3) Restart the plasma mill so that the tuff powder is subjected to plasma treatment for another 10 minutes during the mechanical grinding process, for a total treatment time of 20 minutes.

[0020] Comparative Example 2 Tuff powder treated with plasma for 10 minutes and 20 minutes was used to replace cement at a dosage of 30% according to the method in GB / T 18046-2017. The specific surface area and activity index were tested. It is clear that the longer the plasma treatment time, the higher the activity of the tuff.

[0021] Sample source Specific surface area (m² / kg) 7d activity index (%) 28d activity index (%) Plasma treatment for 10 minutes 353 74 86 Plasma treatment for 20 minutes 412 82 99 Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for enhancing the activity of mineral admixtures in concrete, characterized in that, Includes the following steps: S1: Raw material pretreatment: Crush and dry the mineral admixture raw materials to a moisture content of <1%; S2: Plasma-assisted grinding: The pretreated mineral admixture is fed into a plasma mill for mechanical grinding, and the plasma generator is started to treat the powder with plasma. The plasma generator uses low-temperature plasma. S3: Post-processing: Allow to cool naturally to room temperature after shutdown.

2. The method for enhancing the activity of concrete mineral admixtures according to claim 1, characterized in that, In step S1, the mineral admixture raw material is crushed to a particle size ≤ 5mm.

3. The method for enhancing the activity of concrete mineral admixtures according to claim 1, characterized in that, In step S2, the plasma mill is a ball mill with a built-in plasma generator, and the plasma generator includes a dielectric barrier discharge device or an arc discharge device.

4. The method for enhancing the activity of concrete mineral admixtures according to claim 1, characterized in that, In step S2, the power of the plasma generator is 50-500kW, the frequency is 1-100kHz, the working gas is air, and the discharge mode is continuous discharge.

5. The method for enhancing the activity of concrete mineral admixtures according to claim 1, characterized in that, In step S2, the pretreated mineral admixture is first fed into a plasma mill for mechanical grinding for 10 to 30 minutes, and then the plasma control power supply is turned on for plasma treatment for 2 to 10 minutes.

6. The method for enhancing the activity of concrete mineral admixtures according to claim 1, characterized in that, In step S2, the mineral admixture is subjected to plasma treatment simultaneously during the mechanical grinding process.

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