Ultrasonic-microwave combined chemical leaching remediation device for uranium contaminated soil

Abstract

The utility model relates to the technical field of soil remediation, in particular to an ultrasonic-microwave combined chemical leaching remediation device for uranium contaminated soil, which comprises a reaction kettle for providing microwave treatment and a reaction tank for ultrasonic-assisted leaching. And a reaction cavity for accommodating soil and leacheate is arranged in the reaction kettle. A microwave generator for radiating microwaves into the reaction cavity is arranged on the side wall of the reaction kettle. A feeding hole for pouring soil is formed in the top of the reaction kettle. A liquid adding opening for injecting leacheate is formed in one side of the feeding opening. A discharge hole for discharging washed soil is formed in the bottom of the reaction kettle. And the reaction tank is arranged at the discharge hole of the reaction kettle. And a conveying device for conveying washed soil is arranged between the reaction tank and the reaction kettle. And ultrasonic transducers are arranged at the bottom and on the side wall of the reaction tank. According to the ultrasonic-microwave combined chemical leaching remediation device for the uranium-contaminated soil, the removal rate of uranium in the contaminated soil is increased, and the remediation effect is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of soil remediation, in particular to an ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil. Background Art

[0002] Open-pit uranium mining produces large quantities of waste ore and tailings. These waste ore and tailings often contain high concentrations of uranium. For example, at some large uranium mining sites, after the mined ore is screened, the remaining waste ore is piled up around the mining area. The uranium in this waste ore is gradually released into the surrounding soil through natural processes such as rainwater erosion and wind erosion. Furthermore, the large amounts of topsoil excavated during uranium mining are also contaminated with uranium. If this contaminated topsoil is not properly handled, it can lead to uranium contamination of the soil.

[0003] Currently, treatment methods for uranium-contaminated soil include excavation and landfill, soil leaching, and electrokinetic remediation. Soil leaching uses eluents such as chemical solvents or water, either through a column or in-situ leaching, to dissolve and separate uranium from the soil. Electrokinetic remediation involves inserting electrodes at both ends of the contaminated soil and applying a DC electric field, causing uranium ions to migrate toward the electrodes under the action of the electric field, thereby separating the uranium from the soil.

[0004] However, the above treatment methods all have defects in actual use. For example, soil leaching may change the physical and chemical properties of the soil, such as pH and fertility, and improper selection and treatment of the leaching agent may cause secondary pollution. For another example, the electrokinetic remediation method is only suitable for small areas of low-permeability soil, and may cause problems such as electrode corrosion during the remediation process. In addition, the above treatment methods have poor uranium removal rates in uranium-contaminated soils, and the overall soil remediation cycle is long, which affects the remediation effect. Summary of the Invention

[0005] The purpose of the utility model is to provide a remediation device for the treatment of uranium-contaminated soil, so as to improve the removal rate of uranium in the contaminated soil and enhance the remediation effect.

[0006] In order to achieve the above purpose, the present invention adopts the following scheme:

[0007] An ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil, comprising a reactor for providing microwave treatment and a reaction tank for ultrasonic-assisted leaching;

[0008] The reactor is provided with a reaction cavity for accommodating soil and eluent, a microwave generator for radiating microwaves into the reaction cavity is provided on the side wall of the reactor, a loading port for pouring soil is provided on the top of the reactor, a liquid filling port for injecting eluent is provided on one side of the loading port, and a discharge port for discharging the eluted soil is provided at the bottom of the reactor;

[0009] The reaction tank is arranged at the discharge port of the reactor, a conveying device for conveying leached soil is arranged between the reaction tank and the reactor, and ultrasonic transducers are arranged on the bottom and side walls of the reaction tank.

[0010] Preferably, a water inlet for circulating cooling water is provided on the side wall of the reaction tank, a water outlet is provided at the bottom of the reaction tank, and the water inlet and the water outlet are connected via a circulating cooling pipeline.

[0011] Preferably, a stirring assembly for mixing soil and eluent is provided on the top of the reactor. The stirring assembly includes a stirring motor and a stirring rod. The stirring motor is installed on the top cover of the reactor. The output end of the stirring motor is connected to the stirring rod. The stirring end of the stirring rod is arranged in the reaction chamber.

[0012] Preferably, a screw conveyor for conveying soil is provided at the loading port of the reactor. The screw conveyor is installed on one side of the reactor through a supporting platform, and the output end of the screw conveyor faces the loading port.

[0013] Preferably, a filter bucket is provided at the input end of the screw conveyor.

[0014] Preferably, the frequency of the microwaves generated by the microwave generator is 900 MHz-2450 MHz.

[0015] Preferably, the vibration frequency generated by the ultrasonic transducer is 20kHz-100kHz.

[0016] Compared with the prior art, the ultrasonic-microwave combined chemical leaching and remediation device for uranium contaminated soil provided by the utility model has the following substantial features and progress: the ultrasonic-microwave combined chemical leaching and remediation device for uranium contaminated soil combines microwave treatment and ultrasonic-assisted leaching. The microwave generator radiates microwaves in the reactor, which can intensify the molecular motion of uranium pollutants in the soil and the eluent under the action of the microwave field, causing the temperature of the mixture formed by the eluent and the soil to rise suddenly, which is conducive to penetrating the internal structure of the soil and enhancing the leaching effect of the eluent. At the same time, the ultrasonic transducer in the reaction tank generates ultrasonic waves to further enhance the leaching effect. The ultrasonic waves Physical effects such as the cavitation effect produced in the eluent can destroy the adsorption balance of uranium pollutants on soil particles, allowing the uranium that was originally difficult to remove to come into more complete contact with the eluent and be carried out of the soil, accelerating the dissolution of uranium in different forms, and strengthening the leaching effect of chemical eluents, thereby effectively improving the uranium removal rate. In addition, the combination of two different physical fields, microwaves and ultrasound, with chemical leaching not only promotes the removal of uranium pollutants themselves, but also has a certain improvement effect on problems such as soil structure changes that may be caused by uranium contamination. While promoting uranium desorption, it helps to restore some physical and chemical properties of the soil, further improving the overall remediation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of an ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil in an embodiment of the present utility model.

[0018] Figure 2 yes Figure 1 Schematic diagram of the three-dimensional structure of an ultrasonic-microwave combined chemical leaching remediation device for uranium-contaminated soil from another perspective.

[0019] Figure 3 yes Figure 1 main view.

[0020] Figure numerals: 1. Support platform; 2. Reactor; 3. Reaction tank; 4. Conveying device; 5. Feeding port; 6. Liquid adding port; 7. Discharge port; 8. Water inlet; 9. Water outlet; 10. Stirring assembly; 11. Screw conveyor; 12. Filter bucket. DETAILED DESCRIPTION

[0021] The specific implementation of the present utility model is described in detail below with reference to the accompanying drawings.

[0022] like Figure 1-Figure 3 As shown, in the embodiment of the utility model, an ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil is proposed, which aims to improve the removal rate of uranium in the contaminated soil and enhance the remediation effect.

[0023] The ultrasonic-microwave combined chemical leaching remediation device for uranium-contaminated soil, proposed in an embodiment of the present invention, utilizes a microwave generator to radiate microwaves within a reactor. This microwave field intensifies the molecular motion of uranium contaminants in the soil and the eluent, causing the temperature of the eluent-soil mixture to rise sharply, facilitating penetration into the soil's internal structure and enhancing the eluent's leaching effectiveness. Simultaneously, an ultrasonic transducer within the reactor generates ultrasonic waves, further enhancing the leaching effect. The cavitation effect and other physical effects of the ultrasonic waves in the eluent disrupt the adsorption equilibrium of uranium contaminants on soil particles, allowing previously difficult-to-remove uranium to more fully come into contact with the eluent and be removed from the soil. This accelerates the dissolution of uranium in its various forms and strengthens the leaching effect of the chemical eluent, effectively increasing the uranium removal rate.

[0024] like Figure 1 Combine Figure 2 As shown, an ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil includes a reactor 2 for providing microwave treatment and a reaction tank 3 for ultrasonic-assisted leaching.

[0025] like Figure 1 Combine Figure 3 As shown, a reaction vessel 2 is provided with a reaction chamber for accommodating soil and eluent. A microwave generator is mounted on the sidewall of the reactor 2 to radiate microwaves into the reaction chamber. A loading port 5 is located at the top of the reactor 2 for adding soil. A liquid inlet 6 is located on one side of the loading port 5 for injecting eluent. A discharge port 7 is located at the bottom of the reactor 2 for discharging the eluted soil.

[0026] like Figure 1 Combine Figure 3 As shown, the reaction tank 3 is arranged at the discharge port 7 of the reactor 2. A conveying device 4 for conveying the eluted soil is provided between the reaction tank 3 and the reactor 2. Ultrasonic transducers are provided on the bottom and side walls of the reaction tank 3. However, the ultrasonic transducers are not shown in the figure.

[0027] The microwave generator generates microwaves at frequencies between 900MHz and 2450MHz. At these frequencies, microwaves are effectively absorbed by polar molecules in the soil-eluent system (such as water molecules in the chemical eluent), generating heat and raising the system's temperature. This increased temperature helps accelerate chemical reactions, promoting the reaction between uranium contaminants and the chemical eluent. It also improves the physical properties of the soil, making it easier for uranium contaminants to migrate.

[0028] The ultrasonic transducer generates a vibration frequency of 20kHz-100kHz. By adjusting the intensity and frequency of the ultrasound, the ultrasonic energy is effectively transferred to the soil-elution system within reactor 2. Ultrasonic waves facilitate the detachment of uranium contaminants from the surface of soil particles through cavitation and mechanical vibration, thereby enhancing the elution effect.

[0029] like Figure 1 As shown, the side wall of the reaction tank 3 is provided with a water inlet 8 for the inflow of circulating cooling water. A water outlet 9 is provided at the bottom of the reaction tank 3. The water inlet 8 and the water outlet 9 are connected by a circulating cooling pipeline. In this way, during the ultrasonic-assisted elution process, the circulating cooling water flows in through the water inlet 8 and out through the water outlet 9, which can effectively remove the heat generated during the reaction process, maintain the temperature in the reaction tank 3 stable, help maintain the optimal conditions for the chemical reaction between the eluent and the uranium contaminants, ensure that the rate and balance of the chemical reaction are not negatively affected by temperature changes, and help improve the desorption efficiency of uranium contaminants from the soil.

[0030] like Figure 2 As shown, a stirring assembly 10 for mixing soil and eluent is installed on the top of the reactor 2. The stirring assembly 10 includes a stirring motor and a stirring rod. The stirring motor is mounted on the top cover of the reactor 2. The output end of the stirring motor is connected to the stirring rod. The stirring end of the stirring rod is located within the reaction chamber.

[0031] The stirring assembly 10 is used to achieve more thorough mixing of the soil and eluent at the microscopic level. The stirring motor rotates the stirring rod, which vigorously stirs the reaction chamber, allowing the eluent to penetrate deep into the gaps between soil particles. For uranium-contaminated soil, this thorough mixing ensures more contact between the eluent and the uranium contaminants. Uranium, whether attached to the surface of soil particles or within soil pores, can more effectively come into contact with the eluent, thereby improving the efficiency of uranium dissolution and removal.

[0032] Furthermore, without stirring, local concentration differences between the soil and the eluent may occur within the reactor 2, resulting in either excessive or insufficient leaching in some areas. The stirring assembly 10 breaks down this unevenness through continuous stirring, maintaining a relatively consistent eluent concentration and soil distribution throughout the reaction chamber. This ensures that every soil particle is eluted in a uniform chemical environment, optimizes the remediation effect, and avoids compromising the overall uranium removal rate due to inappropriate local treatment.

[0033] like Figure 2 Combine Figure 3As shown, the feeding opening 5 of the reaction kettle 2 is provided with a screw conveyor 11 for conveying soil. The screw conveyor 11 is installed on one side of the reaction kettle 2 through the support platform 1. The output end of the screw conveyor 11 is opposite to the feeding opening 5. In this way, the screw conveyor 11 can stably convey soil into the reaction kettle 2 through the rotation of its screw blades, ensuring that the soil enters the feeding opening 5 of the reaction kettle 2 at a relatively uniform speed and flow rate, avoiding the accumulation of materials or the lack of local materials in the reaction kettle 2 due to uneven feeding speed, and helping to maintain a stable repair process and improve the consistency and reliability of the repair of uranium-contaminated soil.

[0034] As shown in the drawings, Figure 3 As shown, the input end of the screw conveyor 11 is provided with a filter hopper 12. The filter hopper 12 is used to intercept large-particle impurities such as stones and branches in the soil. During the repair of uranium-contaminated soil, if these large-particle impurities enter the screw conveyor 11 and then enter the reaction kettle 2, they may affect the mixing effect of the soil and the leaching solution, or even damage the screw blades of the screw conveyor 11 or the precision components such as the stirring assembly 10 in the reaction kettle 2. Through the screening of the filter hopper 12, the soil entering the subsequent processing link is ensured to be more uniform in texture, which is beneficial to improve the stability and repair effect of the repair process.

[0035] In order to embody the advantages of the ultrasonic-microwave combined chemical leaching repair device for uranium-contaminated soil in the embodiment of the present application in the use process, the uranium-contaminated soil and the leaching solution are first subjected to microwave treatment, and then subjected to ultrasonic-assisted leaching. Compared with the process of first subjecting the uranium-contaminated soil and the leaching solution to ultrasonic-assisted leaching and then subjecting them to microwave treatment, the process has advantages. In a laboratory environment, a model F-100ST ultrasonic leaching instrument is used in combination with a model Toshiba VT7230 microwave oven to perform a repair experiment on uranium-contaminated soil.

[0036] Among them, the ultrasonic leaching solution is citric acid, the ultrasonic leaching citric acid concentration is 0.05mol / L, the ultrasonic leaching soil and leaching solution ratio is 1:15g / mL, the ultrasonic leaching instrument power is 675W, the ultrasonic leaching instrument leaching temperature is 40℃, the ultrasonic leaching instrument leaching time is 90min, the microwave leaching solution is citric acid, the microwave leaching citric acid concentration is 0.05mol / L, the microwave leaching soil and leaching solution ratio is 1:15g / mL, the microwave power is 300W, the microwave leaching time is 15min, the soil is first subjected to microwave leaching for 15min and then subjected to ultrasonic leaching for 90min.

[0037] Specifically, 10 g of test soil was placed in a polypropylene bottle. 150 mL of 0.05 mol / L citric acid eluent was added at a solid-liquid ratio of 1 / 15 g / mL. The polypropylene bottle containing the eluent-test soil mixture was placed in a microwave apparatus, set to a microwave power of 300 W, and shaken clockwise before placement to ensure thorough mixing of the solid and liquid. Because microwaves can cause the eluent-soil mixture to heat up during the experiment, the experiment was stopped when it approached boiling point and resumed after the mixture cooled. The microwave treatment lasted a total of 15 minutes. The microwaved soil mixture was then placed in a polyethylene bottle, and the ultrasonic temperature and power were set to 40°C and 675 W. Once the water in the ultrasonic apparatus reached the set temperature, the bottle was placed in the bottle and secured. Before securing, the bottle was shaken clockwise to ensure thorough mixing of the solid and liquid. Because the ultrasonic apparatus generates heat during operation, which can increase the water temperature, the condenser water circuit was activated to maintain a constant temperature of 40°C. Ultrasonic treatment was continued for 45 minutes.

[0038] In another exemplary embodiment, the preferred parameters for elution of uranium-contaminated soil are the same as above, but the order of ultrasound-microwave is reversed, i.e., ultrasound first, then microwave.

[0039] The experimental results show that microwave treatment of uranium-contaminated soil and eluent followed by ultrasonic-assisted elution has a better removal effect on radioactive uranium in uranium-contaminated soil. The optimal removal rate of uranium in contaminated soil is 75%, and the energy consumption is 0.525kW•h.

[0040] The present invention is not limited to the specific technical solutions described in the above embodiments. In addition to the above embodiments, the present invention may also have other implementation methods. For those skilled in the art, any technical solution formed by any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil, characterized in that: It includes a reaction kettle (2) for providing microwave treatment, and a reaction tank (3) for ultrasonic-assisted elution; A reaction cavity for accommodating soil and elution liquid is provided in the reactor (2), a microwave generator for radiating microwaves into the reaction cavity is provided on the side wall of the reactor (2), a loading port (5) for pouring soil is provided on the top of the reactor (2), a liquid addition port (6) for injecting elution liquid is provided on one side of the loading port (5), and a discharge port (7) for discharging the eluted soil is provided at the bottom of the reactor (2); The reaction tank (3) is arranged at the discharge port (7) of the reactor (2), a conveying device (4) for conveying leached soil is provided between the reaction tank (3) and the reactor (2), and ultrasonic transducers are provided on the bottom and side walls of the reaction tank (3).

2. The ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil according to claim 1 is characterized in that: A water inlet (8) for flowing circulating cooling water is provided on the side wall of the reaction tank (3), a water outlet (9) is provided at the bottom of the reaction tank (3), and the water inlet (8) and the water outlet (9) are connected via a circulating cooling pipeline.

3. The ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil according to claim 1 is characterized in that: A stirring assembly (10) for mixing soil and eluent is provided on the top of the reactor (2). The stirring assembly (10) comprises a stirring motor and a stirring rod. The stirring motor is mounted on the top cover of the reactor (2). The output end of the stirring motor is connected to the stirring rod. The stirring end of the stirring rod is arranged in the reaction chamber.

4. The ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil according to claim 1, characterized in that: A screw conveyor (11) for conveying soil is provided at the loading port (5) of the reactor (2). The screw conveyor (11) is installed on one side of the reactor (2) via a support platform (1), and the output end of the screw conveyor (11) faces the loading port (5).

5. The ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil according to claim 4, characterized in that: A filter hopper (12) is provided at the input end of the screw conveyor (11).

6. The ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil according to claim 1, characterized in that: The frequency of the microwaves generated by the microwave generator is 900 MHz-2450 MHz.

7. The ultrasonic-microwave combined chemical leaching and remediation device for uranium-contaminated soil according to claim 1, characterized in that: The vibration frequency generated by the ultrasonic transducer is 20kHz-100kHz.

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