Ultrasonic micro-nano bubble cleaning method for coarse aggregate for concrete

Abstract

The invention relates to the technical field of building structures, in particular to an ultrasonic micro-nano bubble cleaning method for coarse aggregate for concrete. Comprising the following steps that S1, coarse aggregate is put into a receiving hopper through a loading machine; s2, the receiving hopper feeds the materials to a conveying belt device through an electronic metering device according to the set mass; s3, the conveying belt device feeds materials to an eccentric vibrating screen device for mechanical vibration; s4, a pressure water washing device is matched with mechanical vibration for spraying and washing; s5, the coarse aggregate subjected to coarse washing through the eccentric vibrating screen device and the pressure water flushing device is fed into a fine washing water tank, a drum screen and an ultrasonic oscillation generator are arranged in the fine washing water tank, and the coarse aggregate is fed into the drum screen; and S6, after cleaning is completed, the aggregate is put into a conveying belt to be conveyed to an aggregate bin. According to the construction method, the ultra-clean and high-efficiency cleaning technology of the coarse aggregate is achieved, the surface of the coarse aggregate is highly clean, and the quality of the bare concrete is guaranteed. The ultrasonic micro-nano bubble cleaning device is mainly applied to the aspect of ultrasonic micro-nano bubble cleaning of coarse aggregates.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete, and more particularly to an ultrasonic micro-nano bubble cleaning method for coarse aggregate for concrete. Background Art

[0002] As bridge and culvert concrete gradually evolves from ordinary concrete to fair-faced concrete, its unique aesthetic, characterized by its natural simplicity and "solidity within," is gaining increasing favor in the engineering community. However, the production process is susceptible to multiple factors, including the quality of the concrete's raw materials. Surface defects such as bubbles, color variations, honeycombing, black spots, and watermarks are particularly prone to appearing. The high volatility of mud and stone dust content in coarse aggregates leads to extremely unstable concrete properties, making the aforementioned defects highly susceptible.

[0003] Currently, the existing coarse aggregate cleaning mainly combines mechanical vibration and water washing, which has the following disadvantages: First, the existing coarse aggregate cleaning equipment is mostly water-irrigation cleaning, which only cleans the easily soluble mud powder on the surface of the coarse aggregate, while the mud powder attached to the surface or concave surface is not cleaned up, resulting in mediocre results; second, the traditional water inlet is normal pressure water injection, which has poor cleaning ability and low efficiency; third, the separation funnel directly discharges the wastewater, and the wastewater cannot be recycled. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a method for ultrasonic micro-nano bubble cleaning of coarse aggregate for concrete. This method achieves ultra-clean and highly efficient cleaning of coarse aggregate, ensuring a highly clean surface and ensuring the quality of clear concrete.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles comprises the following steps: S1. Put the coarse aggregate into the receiving hopper through the loader; S2, the receiving hopper feeds the material to the conveyor belt device according to the set mass through the electronic metering device; S3, the conveyor belt device feeds the material to the eccentric vibrating screen device for mechanical vibration; S4, pressure water washing device with mechanical vibration for spraying and washing; S5. The coarse aggregate after being roughly washed by the eccentric vibrating screen device and the pressure water washing device is sent to the fine washing water tank. The fine washing water tank is equipped with a drum screen and an ultrasonic agitation generator. The coarse aggregate is fed into the drum screen; S6. After cleaning, the aggregate is put into the conveyor belt and sent to the aggregate bin.

[0006] In step S1, the pre-cleaned coarse aggregate is put into a container with a volume of 0.5-2.0m 3 The receiving hopper is equipped with a vibration motor and an electronic metering device. By adjusting the power and amplitude of the vibration motor, the amount of coarse aggregate discharged can be controlled, and the metering device can roughly measure the quality of the cleaned gravel.

[0007] In the step S2, after the aggregate is unloaded, the cleaned coarse aggregate is transported by a conveyor belt device with a length of 10m-15m and a width of 0.65-1.2m.

[0008] In step S3, the inclination angle of the vibrating screen in the eccentric vibrating screen device is 3-6°.

[0009] In step S4, the wastewater after washing the coarse aggregate is discharged into the runoff separation channel and finally flows back to the sedimentation tank, and can be recycled after sedimentation.

[0010] In step S5, the drum screen is tilted and placed inside the water tank so that the center line of the drum screen is immersed in the water tank, and the ultrasonic excitation generator is fixed on both sides and the bottom of the water tank.

[0011] In step S5, the aggregate first passes through the self-rotating drum screen, so that the coarse aggregate is fully rolled and dispersed inside the water tank, thereby improving the full contact between the cleaning water, micro-nano bubbles and the aggregate; at the same time, when the aggregate falls into the water, a composite cleaning of ultrasonic agitation + mechanical rolling is formed. At this time, a large amount of high-energy water and micro-nano bubbles shuttle between the interface layer of the coarse aggregate and the adhered powder, thereby realizing ultrasonic fine cleaning of the coarse aggregate.

[0012] In step S6, the conveyor belt transports the material to the collecting bin, and the generated sewage flows into the separation channel and finally flows back to the sedimentation tank, and can be recycled after sedimentation.

[0013] The ultrasonic generator consists of multiple ultrasonic units, which are evenly distributed; the frequency of the ultrasonic wave is in the range of 0-20kHZ.

[0014] During the super-washing process, the cleanliness of the cleaned coarse aggregate is tested in time. The direct purpose of the test is to test the cleanliness of the cleaned coarse aggregate. The test steps are to brush the cleaned coarse aggregate with a wire brush and then put it into clean water. The water is clear and no powder is generated or the mass generated is not more than 0.1%. The indirect purpose of the test is to adjust the parameters of the washing machine according to the cleanliness of the aggregate, and adjust the minimum energy consumption value under the premise of meeting the washing quality requirements.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The appearance quality of the aggregates improved significantly after ultra-cleaning, and the pass rate for zero-powder aggregate spot checks increased significantly. Internal quality also improved slightly. Comparisons of the compressive strength of concrete before and after cleaning revealed a slight improvement across all strength grades, with a more pronounced improvement for low-grade concrete. High aggregate cleanliness enhances the interfacial bond between the aggregate and the cement mortar. Concrete workability tests confirmed that high aggregate cleanliness improves concrete workability, ensuring that the coarse aggregate remains saturated with water, facilitating calculation of overall water consumption. This stable workability provides a robust and operational foundation for fair-faced concrete manufacturing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the cleaning process of the present invention; In the figure: 1 is the receiving hopper, 2 is the conveyor belt device, 3.1 is the eccentric vibrating screen device, 3.2 is the pressure water washing device, 4 is the drum screen, and 5 is the collecting bin. DETAILED DESCRIPTION

[0017] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from the description. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0019] like Figure 1 As shown, a method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles is characterized by comprising the following steps: S1, using a loader to put coarse aggregate into the receiving hopper 1; S2, the receiving hopper 1 feeds the material to the conveyor belt device 2 according to the set mass through the electronic metering device; S3, the conveyor belt device 2 feeds the eccentric vibrating screen device 3.1 for mechanical vibration; S4, pressure water washing device 3.2 cooperates with mechanical vibration to spray water washing; S5. The coarse aggregate after rough washing by the eccentric vibrating screen device 3.1 and the pressure water washing device 3.2 is fed into the fine washing water tank. The fine washing water tank is equipped with a drum screen 4 and an ultrasonic excitation generator. The coarse aggregate is fed into the drum screen 4. S6. After cleaning, the aggregate is put into the conveyor belt and sent to the aggregate bin 5.

[0020] Preferably, in step S1, the pre-cleaned coarse aggregate is put into a container with a volume of 0.5-2.0m3 The receiving hopper 1 is equipped with a vibration motor and an electronic metering device. By adjusting the power and amplitude of the vibration motor, the amount of coarse aggregate discharged can be controlled, and the metering device can roughly measure the quality of the cleaned gravel. It is more suitable for coarse aggregates with large mud content or produced on rainy days to prevent material jamming and uneven discharge. Preferably, in step S2, after the aggregate is unloaded, the cleaned coarse aggregate is transported by a conveyor belt device 2 with a length of 10m-15m and a width of 0.65-1.2m.

[0021] Preferably, in step S3, the inclination angle of the vibrating screen in the eccentric vibrating screen device 3.1 is 3-6°.

[0022] Preferably, in step S4, the wastewater after washing the coarse aggregate is discharged into a runoff separation channel and finally flows back to a sedimentation tank, and can be recycled after sedimentation.

[0023] Preferably, in step S5, the drum screen 4 is tilted and placed inside the water tank so that the center line of the drum screen 4 is immersed in the water tank, and the ultrasonic excitation generator is fixed on both sides and the bottom of the water tank.

[0024] Preferably, in step S5, the aggregate first passes through the self-rotating drum screen 4, so that the coarse aggregate is fully rolled and dispersed inside the water tank, thereby improving the full contact between the cleaning water, micro-nano bubbles and the aggregate; at the same time, when the aggregate falls into the water, a composite cleaning of ultrasonic agitation + mechanical rolling is formed. At this time, a large amount of high-energy water and micro-nano bubbles shuttle between the interface layer of the coarse aggregate and the adhered powder, thereby realizing ultrasonic fine cleaning of the coarse aggregate.

[0025] Preferably, in step S6, the conveyor belt transports the wastewater to the collecting bin 5, and the wastewater generated flows through the separation channel and finally flows back to the sedimentation tank, and can be recycled after sedimentation.

[0026] The ultrasonic generator consists of multiple ultrasonic units, which are evenly distributed; the frequency of the ultrasonic wave is in the range of 0-20kHZ.

[0027] During the super-washing process, the cleanliness of the cleaned coarse aggregate is tested in time. The direct purpose of the test is to test the cleanliness of the cleaned coarse aggregate. The test steps are to brush the cleaned coarse aggregate with a wire brush and then put it into clean water. The water is clear and no powder is generated or the mass generated is not more than 0.1%. The indirect purpose of the test is to adjust the parameters of the washing machine according to the cleanliness of the aggregate, and adjust the minimum energy consumption value under the premise of meeting the washing quality requirements.

[0028] The method combines mechanical vibration water washing, i.e. rough washing, and ultrasonic water washing, i.e. fine washing. In particular, the second step realizes the application of ultrasonic water washing in civil engineering projects of super-large size and scale. The practice has proven that this innovative technology can achieve fast, efficient and deep cleaning of coarse aggregates, and use the technology of physical seepage to purify the washing water, thereby achieving the recycling of water resources, which is in line with the concept of energy-saving and environmentally friendly quality highway construction.

[0029] For aggregate surfaces with large amounts of mud or stone dust, clean water used for mixing is used as an ultrasonic cleaning medium. Aggregates are conveyed via a feed conveyor to a rough washing unit equipped with a pressure water flushing device and mechanical eccentric vibration. The frequency and amplitude of the eccentric vibration unit are adjusted, and the material speed is adjusted based on the coarse aggregate particle size and feed rate, achieving the first step of rough washing. The key function of rough washing is to remove adherent powder, fine particles smaller than 4.75mm, and soft, large soil particles. Water pressure cleaning during rough washing primarily removes less adherent stone dust, wetting the aggregate through water permeability and the pore water absorption of the powder. A mechanical eccentric vibrator screen uses eccentric vibration to break up and shatter stone dust adhering to the aggregate surface. Water flushing and a 4mm steel sieve separate the stone dust. Rough washing is essential because grading the aggregate reduces resistance and energy consumption for the next step of fine washing.

[0030] After rough washing, the aggregate is conveyed by a conveyor belt to an ultrasonic cleaning tank, a 15° inclined steel drum screen, an ultrasonic vibrating plate (equipped with a certain number of ultrasonic transmitters), and a screen plate for fine cleaning. Ultrasonic fine cleaning technology is based on the characteristics of ultrasonic waves: short wavelength, high energy, and strong excitation. The high-energy waves impart equal impact energy to the medium water, stimulating the generation of micro- and nano-bubbles in the water. Bubble nuclei form and grow instantaneously in the negative pressure zone of the longitudinal propagation of the ultrasound wave, generating instantaneous high-pressure energy of approximately 10 atmospheres. This bubble nucleus penetrates the interface between the aggregate and the adhering material. At this interface, a continuous stream of transient high-pressure bubbles bombards the surface of the aggregate being cleaned like a series of small explosions, achieving highly clean aggregate. The aggregate then passes through a 15° inclined vibrating drum screen, rapidly separating fine powder from coarse aggregate. The wavelength and frequency of the ultrasonic generator can be adjusted according to the cleanliness of the aggregate, effectively matching cleanliness performance and efficiency. To adjust vibration, ultrasonic, and other parameters for rough and fine washing, the entire washing system features a visual user interface for setting cleaning parameters. These parameters can be adjusted at any time based on the cleanliness of the discharged material. To conserve water, the super-wash and fine-wash system is equipped with a wastewater purification system. This system features a screening and interception device. Process wastewater flows through a circular runoff ditch, where particles larger than 0.075mm are separated by gravity. Particles smaller than 0.075mm pass through a sedimentation tank, where water and powder are separated. The progressive filtration system, wastewater sedimentation tank, and circulating water storage tank facilitate the recycling of water resources, preventing the indiscriminate discharge of wastewater and enabling the reuse of water resources.

[0031] The above only describes in detail the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the scope of protection of the present invention.

Claims

1. A method for cleaning coarse aggregate of concrete using ultrasonic micro-nano bubbles, characterized in that: The following steps are involved: S1, coarse aggregate is put into the receiving hopper (1) by a loader; S2, the receiving hopper (1) feeds the material to the conveyor belt device (2) according to the set mass through the electronic metering device; S3, the conveyor belt device (2) feeds the eccentric vibrating screen device (3.1) for mechanical vibration; S4, pressure water washing device (3.2) with mechanical vibration for spraying and washing; S5, the coarse aggregates that have been roughly washed by the eccentric vibrating screen device (3.1) and the pressure water washing device (3.2) are fed into a fine washing water tank, in which a drum screen (4) and an ultrasonic agitation generator are provided, and the coarse aggregates are fed into the drum screen (4); S6. After cleaning, the aggregate is put into the conveyor belt and sent to the aggregate bin (5).

2. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In step S1, the pre-cleaned coarse aggregate is put into a container with a volume of 0.5-2.0m 3 A receiving hopper (1) is provided with a vibration motor and an electronic metering device. By adjusting the power and amplitude of the vibration motor, the amount of coarse aggregate discharged can be controlled, and the metering device can roughly measure the quality of the cleaned gravel.

3. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In the step S2, after the aggregate is unloaded, the cleaned coarse aggregate is transported by a conveyor belt device (2) having a length of 10m-15m and a width of 0.65-1.2m.

4. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In step S3, the inclination angle of the vibrating screen in the eccentric vibrating screen device (3.1) is 3-6°.

5. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In step S4, the wastewater after washing the coarse aggregate is discharged into the runoff separation channel and finally flows back to the sedimentation tank, and can be recycled after sedimentation.

6. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In step S5, the drum screen (4) is tilted and placed inside the water tank so that the center line of the drum screen (4) is immersed in the water tank, and the ultrasonic excitation generator is fixed to the two side surfaces and the bottom surface of the water tank.

7. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In step S5, the aggregate first passes through the self-rotating drum screen (4), so that the coarse aggregate is fully rolled and dispersed in the water tank, thereby improving the full contact between the cleaning water, micro-nano bubbles and the aggregate; at the same time, when the aggregate falls into the water, a composite cleaning of ultrasonic agitation + mechanical rolling is formed, at which time a large amount of high-energy water and micro-nano bubbles shuttle between the interface layer of the coarse aggregate and the adhered powder, thereby achieving ultrasonic fine cleaning of the coarse aggregate.

8. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 1, characterized in that: In step S6, the conveyor belt transports the material to the collecting bin (5), and the generated sewage flows through the separation channel and finally flows back to the sedimentation tank, and can be recycled after sedimentation.

9. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 7, characterized in that: The ultrasonic generator consists of multiple ultrasonic units, which are evenly distributed; the frequency of the ultrasonic wave is in the range of 0-20kHZ.

10. The method for cleaning coarse aggregate for concrete using ultrasonic micro-nano bubbles according to claim 7, characterized in that: During the super-washing process, the cleanliness of the cleaned coarse aggregate is tested in time. The direct purpose of the test is to test the cleanliness of the cleaned coarse aggregate. The test steps are to brush the cleaned coarse aggregate with a wire brush and then put it into clean water. The water is clear and no powder is generated or the mass generated is not more than 0.1%. The indirect purpose of the test is to adjust the parameters of the washing machine according to the cleanliness of the aggregate, and adjust the minimum energy consumption value under the premise of meeting the washing quality requirements.

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