A method of extracting uranium oxide

Abstract

This application provides a method for extracting uranium oxide. Step 1: Prepare an electrolysis apparatus, which includes an electrolysis cell, a cathode, an anode, and an ultrasonic transducer mounted on the cathode. Step 2: Place a uranium-containing solution in the electrolysis cell and perform ultrasonic-assisted electrolysis treatment, wherein the pH of the uranium-containing solution is 0-5.5; the voltage for the ultrasonic-assisted electrolysis treatment is set to +0.32V-0V vs. a standard hydrogen electrode, and the current is set to 1-500mA / cm². 2 Step 3: Collect uranium oxide deposits. This application applies continuous or pulsed high-frequency ultrasonic vibrations during electrolysis, causing the UO2 deposits to be desorbed before forming a dense coating on the electrode. This effectively reduces electrode passivation and the difficulty in sustaining the electrolysis reaction, achieving stable, continuous, and efficient extraction of UO2 powder.

Description

Technical Field

[0001] This application relates to the field of radioactive waste treatment and resource recovery technology, and in particular to a method for extracting uranium oxide. Background Technology

[0002] Uranium is a key raw material for nuclear energy. With the deepening of the closed-loop nuclear fuel cycle and the treatment and recycling of nuclear waste, the development of efficient, green, and sustainable uranium extraction technologies from uranium-containing solutions is of significant strategic importance. Uranium-containing solutions come from a wide range of sources, including traditional uranium ore leaching solutions, hydrometallurgical tailings, spent fuel reprocessing solutions, low-concentration radioactive wastewater generated during nuclear facility operation, and even seawater with extremely low uranium concentrations. In recent years, seawater uranium extraction has received widespread attention due to its extremely abundant uranium reserves (approximately 4.5 billion tons), becoming an important supplementary direction for future nuclear fuel resource security. Furthermore, the recovery and utilization of uranium from nuclear industry wastewater can significantly reduce the radioactive pollution burden and treatment costs, especially suitable for special and complex scenarios such as equipment cleaning fluids and concentrate distillation residues. Existing uranium extraction technologies include solvent extraction, ion exchange, adsorption, precipitation, membrane separation, and electrochemical reduction. Among these, electrochemical methods offer advantages such as simple operation, environmental friendliness, no additive pollution, and strong controllability. However, in practical engineering applications, such as in-situ nuclear waste treatment systems, continuous uranium enrichment modules for seawater extraction, and electroreduction units for concentrated liquids, the deposited uranium oxide (UO2) has electrical insulation properties, leading to problems such as electrode passivation, which restricts the continuity, stability, and efficiency of electrochemical uranium extraction technology. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a method for extracting uranium oxide, which can solve the problems of electrode passivation caused by the electrical insulation of the electrolysis product UO2, the difficulty in sustaining the electrochemical reaction, and the inability to achieve continuous operation of the uranium extraction process, thereby improving the continuity, stability and efficiency of electrochemical uranium extraction technology.

[0004] To achieve this objective, this application provides a method for extracting uranium oxide, the method comprising:

[0005] Step 1: Prepare an electrolysis apparatus, which includes an electrolytic cell, a cathode, an anode, and an ultrasonic transducer disposed on the cathode;

[0006] Step 2: Place the uranium-containing solution in the electrolytic cell and perform ultrasonic-assisted electrolysis treatment, wherein the pH of the uranium-containing solution is 0-5.5; the voltage for ultrasonic-assisted electrolysis treatment is set to +0.32V-0V vs standard hydrogen electrode, and the current is set to 1-500mA / cm. 2 ;

[0007] Step 3: Collect uranium oxide deposits.

[0008] In some embodiments, in step 2, the uranium-containing solution includes UO2. 2+ Ions, the UO2 2+ The ion concentration is 50 ppb-10000 ppm.

[0009] In some embodiments, the voltage of the ultrasonic-assisted electrolysis treatment remains constant in step 2.

[0010] In some embodiments, the current for the ultrasonic-assisted electrolysis treatment remains constant in step 2.

[0011] In some embodiments, in step 2, the ultrasonic power of the ultrasonic-assisted electrolysis treatment is set to 30-1000W, and the ultrasonic frequency is set to 20-80kHz.

[0012] In some embodiments, the ultrasound-assisted electrolysis treatment is configured to be performed simultaneously with the ultrasound treatment.

[0013] In some embodiments, the ultrasonic-assisted electrolysis treatment is configured to alternate between ultrasonic treatment and electrolysis treatment, with the electrolysis treatment time period set to 1 min-30 min and the ultrasonic treatment time period set to 5 s-5 min.

[0014] In some embodiments, the ultrasonic-assisted electrolysis treatment is configured to be performed continuously and the ultrasonic treatment is performed intermittently, wherein the duration of the ultrasonic treatment is set to 5s-5min and the interval of the ultrasonic treatment is set to 5s-30min.

[0015] In some embodiments, the cathode is made of titanium or stainless steel.

[0016] In some embodiments, the distance between the cathode and the anode is set to 20-80 mm.

[0017] The method for extracting uranium oxide provided in this application involves loading an ultrasonic transducer onto a cathode electrode rod and applying continuous or pulsed high-frequency ultrasonic vibrations during electrolysis. This causes the UO2 deposits obtained from electrolysis to be desorbed before forming a dense coating layer on the electrode, significantly increasing the renewal frequency of the working electrode surface. This avoids complex processes such as electrode replacement or surface renewal, reduces energy consumption, and improves the continuity and stability of production. Under acidic conditions, this method operates within a positive potential range close to the standard reduction potential of uranyl ions (approximately +0.32V vs. standard hydrogen electrode), effectively reducing hydrogen evolution side reactions and improving electrolysis efficiency. Furthermore, by synergistically integrating ultrasonic and electrochemical processes and adjusting the application method (e.g., continuous or intermittent), frequency, and power of the ultrasound, the problems of electrode passivation and difficulty in sustaining the electrochemical reaction are effectively avoided, achieving stable, continuous, and efficient extraction of UO2 powder in weakly acidic uranium-containing solutions. In addition, by adjusting the ultrasonic parameters, UO2 powders of different particle sizes can be obtained controllably to meet different production needs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an electrolysis apparatus according to an embodiment of this application.

[0019] Figure 2 This is a particle size distribution diagram of uranium oxide powder from Example 1 of this application.

[0020] Figure labels: 1 Electrolyte; 2 Electrolytic cell; 3 Reference electrode; 4 Anode; 5 Ultrasonic transducer; 6 Cathode rod / plate; 7 Collection basket; 8 Electrolysis control system; 9 Ultrasonic control system. Detailed Implementation

[0021] The technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In the event of any conflict, this specification shall prevail.

[0023] It should be noted that, in the embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a method or apparatus that includes a list of elements includes not only the elements expressly stated, but also other elements not expressly listed, or elements inherent to implementing the method or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other related elements in the method or apparatus that includes that element.

[0024] Electrochemical methods have wide applications in energy, chemical engineering, environmental protection, and materials science. Their core principle is the directional transfer of electrons in redox reactions via electrodes, essentially involving the interconversion of chemical and electrical energy. Electrochemical methods rely on an electrochemical system, including a cathode, anode, electrolyte, and external circuitry. The anode loses electrons, undergoing oxidation; the cathode gains electrons, undergoing reduction. The electrolyte provides an environment for ion migration and maintains charge balance. Specifically, oxidation occurs at the anode, and driven by the potential difference in the external circuit, electrons are transferred from the anode to the cathode, converting cations (such as UO₂⁻) into electrons. + The electrons move toward the cathode and gain electrons there, thus undergoing a reduction reaction.

[0025] Electrochemical extraction of uranium offers advantages such as simple operation, environmental friendliness, no additive pollution, and strong controllability, and is widely used in nuclear wastewater purification, uranium smelting tailings recovery, and seawater uranium extraction. In uranium-containing solutions such as nuclear wastewater, uranium smelting tailings, and seawater, the +6 valence uranyl ion (UO2)... 2+ Uranium oxide (UO2) is one of the most stable soluble oxidation states. When uranium exists primarily as uranyl ions in solution, uranium can be extracted electrochemically. The principle behind this is mainly based on the uranyl ion (UO2) oxidation state. 2+ The reduction reaction that occurs on the cathode surface of the electrolytic cell to produce UO2 deposits can be represented as: UO2 2+ +2e - → UO2(s). The reduction potential of uranyl ions is relatively positive (+0.32V vs standard hydrogen electrode), and the reaction occurs relatively easily. However, the resulting UO2 deposit has extremely high resistivity (10⁻⁶V) at room temperature. 8 -10 12UO2 (Ω·cm) is a typical electrical insulator. Continuous deposition of UO2 on the cathode forms an insulating UO2 coating on the electrode surface, hindering electron transport. This manifests as rapid current decay and increased electrode polarization, ultimately causing the electrolysis reaction to cease within a short time. This has become a technical bottleneck restricting the industrial application of electrochemical reduction for uranium extraction. Replacing the electrode or removing the deposits from the electrode surface is the most direct solution, which can temporarily maintain the electrolysis reaction. However, this method increases economic costs and cannot meet the continuous operation requirements of closed or radioactive liquid handling systems. While external high-flow-rate flushing and agitation can prevent continuous deposition on the electrode, these methods suffer from operational complexity, high energy consumption, and low efficiency.

[0026] Therefore, a method for the stable, continuous, and efficient extraction of uranium oxide from uranium-containing solutions is needed.

[0027] In view of this, this application provides a method for extracting uranium oxide, the method comprising:

[0028] Step 1: Prepare an electrolysis apparatus, which includes an electrolytic cell, a cathode, an anode, and an ultrasonic transducer disposed on the cathode;

[0029] Step 2: Place the uranium-containing solution in the electrolytic cell and perform ultrasonic-assisted electrolysis treatment, wherein the pH of the uranium-containing solution is 0-5.5; the voltage for ultrasonic-assisted electrolysis treatment is set to +0.32V-0V vs standard hydrogen electrode, and the current is set to 1-500mA / cm. 2 ;

[0030] Step 3: Collect uranium oxide deposits.

[0031] Uranium-containing solutions include uranyl ions (UO2). 2+ Its form varies at different pH levels: for example, under acidic conditions it exists as UO2. 2+ Primarily; forms UO2(OH) under neutral to weakly alkaline conditions. + Hydroxyl complexes such as (UO2)2(OH)22+ form UO2(OH)42- under strongly alkaline conditions, and their morphology directly affects their reduction efficiency on the electrode. By maintaining the pH of the uranium-containing solution within the range of 0-5.5, in acidic solutions, H... + Higher concentrations inhibit the hydrolysis of uranyl ions, allowing uranium to remain free UO2. 2+ It exists stably in the electrolyte, thus enabling the electrolysis of UO2. 2+ Reduced to UO2 2+This yields UO2 powder with high recovery rate. Exemplarily, the pH of the uranium-containing solution can be 0, 0.5, 1.0, 1.5, 2.5, 3.5, 4.5, 5.5, or a range consisting of any two of these values. The pH of the uranium-containing solution can be adjusted using methods known in the art. For example, it can be adjusted using dilute nitric acid or dilute sulfuric acid solution.

[0032] In some embodiments, the uranyl ion concentration of the uranium-containing solution is 50 ppb-10000 ppm. The method for extracting uranium oxide provided in this application can be applied to different scenarios, including low-concentration uranium resource recovery (such as seawater) and high-concentration uranium solution treatment (such as ore leaching solutions). The uranium concentration in seawater, surface water, or radioactive wastewater is typically in the ppb range, while the uranium concentration in ore leaching solutions is typically in the ppm range.

[0033] In some embodiments, the uranium-containing solution includes uranium tailings leaching solution, radioactive wastewater, natural seawater, or artificially prepared simulated solution.

[0034] In step 2 of this application, the voltage of the ultrasonic-assisted electrolysis treatment is set to +0.32V-0V vs. a standard hydrogen electrode (SHE), and the current is set to 1-500mA / cm. 2 Choosing a potential close to the standard reduction potential of uranyl ions can ensure the stability of UO2. 2+ In the electrolytic reaction, it is preferentially reduced, minimizing interference from impurity ions and improving product purity. Furthermore, low voltage reduces energy consumption per unit of uranium extraction, thereby lowering industrial costs. For example, the voltage for the ultrasonic-assisted electrolysis treatment can be set to +0.32V, +0.3V, +0.25V, +0.2V, +0.15V, +0.1V, +0.05V, 0V, or any two of these values. Using a low-density current can suppress side reactions and improve the selectivity of the electrolysis reaction; using a high-density current can achieve rapid preparation of UO2 powder and improve recovery efficiency. For example, the current for the ultrasonic-assisted electrolysis treatment can be set to 1 mA / cm². 2 50mA / cm 2 100mA / cm 2 150mA / cm 2 200mA / cm 2 250mA / cm 2 300mA / cm 2 400mA / cm 2 500mA / cm 2 Or the value between any two of them within a range.

[0035] In some embodiments, the voltage of the ultrasonic-assisted electrolysis treatment in step 2 remains constant. Maintaining a constant voltage means that the voltage applied between the two electrodes is kept at a fixed value by an external power supply. The principle is that the power supply uses an internal feedback adjustment mechanism to monitor the output voltage in real time. When the voltage deviates from the set value due to changes in the resistance of the reaction system (such as a decrease in solution concentration or the formation of an insulating layer on the electrode surface), the power supply automatically adjusts the output current to maintain voltage stability. If the constant voltage is set reasonably, side reactions caused by excessive voltage (such as hydrogen evolution side reactions) can be reduced. It is understood that when the voltage of the ultrasonic-assisted electrolysis treatment remains constant, there is no limitation on the current. Those skilled in the art can adjust the current as needed; specifically, a low current can reduce side reactions, while a high current can increase the electrolysis rate.

[0036] In some implementations, the current in step 2 of the ultrasonic-assisted electrolysis process remains constant. Maintaining a constant current means that, through an external power supply, the current flowing between the two electrodes is kept at a fixed value, resulting in a constant amount of electrons transferred per unit time. The principle is that the power supply monitors the current in the circuit in real time. When the resistance of the reaction system changes (e.g., reactant consumption, increased electrode polarization), the power supply automatically adjusts the output voltage (by increasing or decreasing the voltage to compensate for resistance changes) to maintain a stable current. Maintaining a constant current results in a fixed amount of product generated per unit time, a uniform reaction rate, and precise control of product yield. It is understood that when the current in the ultrasonic-assisted electrolysis process is constant, the voltage cannot be lower than 0V to prevent hydrogen evolution reaction at the cathode.

[0037] In some embodiments, when the current of the ultrasonic-assisted electrolysis treatment is constant, the electrolysis device is a dual-electrode electrolysis device, that is, the electrodes in the electrolysis device are a cathode and an anode.

[0038] In some embodiments, in step 2 of this application, the ultrasonic-assisted electrolysis treatment further includes, simultaneously with electrolysis, directly transmitting acoustic energy through an ultrasonic transducer on the cathode to the cathode interface, thereby achieving continuous or intermittent synergistic control of ultrasound and electrolysis, ensuring timely stripping of deposited products on the cathode surface, and maintaining reactivity. This application does not specifically limit the type and model of the ultrasonic transducer mounted on the cathode; those skilled in the art can select a suitable ultrasonic transducer based on the required ultrasonic frequency and power. For example, the ultrasonic transducer has a power of 30-1000W and the ultrasonic frequency can be adjusted to 20-80kHz. Specifically, the exemplary ultrasonic transducer can be selected from a high-power piezoelectric ceramic transducer.

[0039] In some embodiments, the ultrasonic power of the ultrasonic-assisted electrolysis treatment is set to 30-1000W, and the ultrasonic frequency is set to 20-80kHz. Exemplarily, the ultrasonic power of the ultrasonic-assisted electrolysis treatment can be set to 30W, 50W, 100W, 200W, 300W, 400W, 500W, 600W, 700W, 800W, 900W, 1000W, or a value within a range of any two values ​​thereof. Exemplarily, the ultrasonic frequency of the ultrasonic-assisted electrolysis treatment can be set to 20kHz, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, 80kHz, or a value within a range of any two values ​​thereof.

[0040] In some embodiments, the ultrasound-assisted electrolysis treatment is configured to be performed simultaneously with the ultrasound treatment. This simultaneous ultrasound treatment and electrolysis means that during electrolysis, the ultrasonic transducer continuously transmits acoustic energy through the cathode to the cathode interface; simultaneously, an external power supply continuously outputs voltage and current applied to the cathode and anode. This method is suitable for uranium extraction from high-concentration uranium systems, ensuring timely stripping of generated UO2 deposits, maintaining the reactivity of the electrolysis system, and improving the recovery rate.

[0041] In some embodiments, the ultrasonic-assisted electrolysis treatment is configured to alternate between ultrasonic treatment and electrolysis treatment. The electrolysis treatment time period is set to 1 min-30 min, and the ultrasonic treatment time period is set to 5 s-5 min. The alternation of ultrasonic treatment and electrolysis treatment means that an external power supply first continuously outputs voltage and current applied to the cathode and anode for a period of time. After the output stops, the ultrasonic transducer immediately and continuously conducts acoustic energy through the cathode to the cathode interface for a period of time. After the ultrasonic treatment stops, the aforementioned electrolysis treatment is immediately performed again, and this cycle is repeated. By alternating between electrolysis and ultrasonic treatment for a period of time, the continuous growth process of the deposit is disrupted, prompting it to detach from the electrode surface and enter the liquid phase during the nucleation stage, thus maintaining the electrode's reactivity. Furthermore, the alternation of ultrasonic treatment and electrolysis treatment allows for precise control of the nucleation, growth, and exfoliation stages of the deposit, achieving controllable UO2 particle size. By setting the electrolysis treatment time within the aforementioned range, sufficient time is provided for uranium ions to migrate to the anode and for the uranium ion reduction reaction. This ensures that the uranium ions dissolved in the electrolyte can fully react at the electrode interface and gradually establish a stable electrode reaction kinetic equilibrium. This prevents insufficient uranium ion reduction due to excessively short electrolysis time, or the accumulation of a passivation layer on the electrode surface due to excessively long time, thus reducing electrolysis efficiency. Similarly, setting the ultrasonic treatment time within the aforementioned range effectively removes uranium oxide deposits and other impurities adhering to the anode surface. The brief and concentrated ultrasonic energy maximizes the physical enhancement effect, preventing weak cavitation due to excessively short ultrasonic time, which would fail to remove deposits from the electrode surface; or excessive heat effects due to excessively long time, which would lead to instability in the electrolyte concentration system, electrode coating detachment, and cavitation impacts that disrupt the stability of the established electrode-uranium ion reaction interface, thus reducing electrolysis efficiency.

[0042] In some embodiments, the ultrasound-assisted electrolysis is configured to be continuous while the ultrasound treatment is intermittent, with the ultrasound treatment time set to 5 seconds to 5 minutes and the interval between treatments set to 5 seconds to 30 minutes. An external power supply continuously applies voltage or current to the cathode and anode to maintain reaction activity. Simultaneously, the ultrasound transducer is turned on for a period of time to conduct acoustic energy through the cathode to the cathode interface, then turned off for a period of time, and this cycle is repeated. This method achieves stable reduction and continuous extraction of uranium. Setting the ultrasound treatment time within the aforementioned range allows for timely removal of the deposit from the anode surface during continuous electrolysis to generate uranium oxide deposits, effectively reducing electrode passivation, maintaining electrode reactivity, and improving reaction efficiency. Furthermore, stopping the ultrasound treatment for a period of time allows for control of the electrolyte temperature, balance of ion concentration, and further improvement of reaction efficiency.

[0043] Those skilled in the art will understand that the electrolytic cell used in the method of this application needs to have good corrosion resistance, electrical insulation, and chemical stability, as well as sufficient mechanical strength to maintain electrolytic reaction efficiency, ensure equipment safety, and extend equipment life. This application does not impose specific limitations in this regard, and those skilled in the art can choose suitable materials for the electrolytic cell. Exemplarily, in some embodiments, the electrolytic cell is made of polytetrafluoroethylene, glass, or stainless steel.

[0044] In some embodiments, the cathode is selected from titanium or stainless steel. These materials possess electrical conductivity, corrosion resistance, and low acoustic impedance. The good electrical conductivity and corrosion resistance enable the electrolytic reaction to occur continuously and effectively; the corrosion resistance prevents electrode damage; and the low acoustic impedance material effectively transmits the ultrasonic vibrations emitted by the ultrasonic transducer to the cathode interface, ensuring timely removal of deposited products from the cathode surface and maintaining reaction activity.

[0045] In some embodiments, the anode is selected from inert materials or reactive sacrificial materials. Inert materials refer to materials that do not undergo oxidation during the electrolysis reaction, but only act as carriers for electron transfer, ensuring that anions or other reducing substances in the electrolyte are oxidized at the anode. Inert materials can be reused for a long time, avoiding anode wear and ensuring the stability of the electrolysis reaction. In some embodiments, platinum or graphite is selected as the inert material.

[0046] Reactive sacrificial materials are materials that preferentially undergo oxidation during the electrolysis reaction, used to protect the cathode from corrosion by the electrolysis reaction.

[0047] In some embodiments, the reactive sacrificial material is selected from zinc or tin.

[0048] In some embodiments, the distance between the cathode and the anode is set to 20-80 mm. Maintaining this distance within this range helps reduce solution resistance and minimizes additional energy loss. A suitable distance, while reducing resistance, also ensures sufficient convection and diffusion of the solution, reduces concentration polarization, allows the reaction to proceed more efficiently, and suppresses the generation of side reactions. Exemplarily, the distance between the cathode and the anode can be 20 mm, 50 mm, 60 mm, 70 mm, 80 mm, or a value within a range of any two of these values. In some alternative embodiments, the distance between the cathode and the anode is set to 20 mm, 50 mm, or 80 mm.

[0049] In some embodiments, the electrolysis apparatus further includes a reference electrode. In some optional embodiments, the reference electrode is a saturated calomel electrode, a silver / silver chloride electrode, or a platinum reference electrode. The reference electrode can be used to measure the potential difference between the working electrode (anode or cathode) and the reference electrode, indirectly monitoring the absolute potential of the working electrode, and, in conjunction with instruments (such as a potentiostat), adjusting the applied voltage to stabilize the potential of the working electrode within the potential range of the target reaction, thereby suppressing side reactions, improving electrolysis efficiency, and increasing product purity.

[0050] In some embodiments, the uranium oxide deposits described in step 3 are guided by the fluid into a collection basket for collection.

[0051] In some embodiments, the uranium oxide deposits in step 3 are separated using a microporous filter, a centrifuge, or by static settling.

[0052] In some embodiments, the pore size of the microporous filter is 0.2-0.5 μm.

[0053] In some embodiments, the preparation method further includes washing the uranium oxide deposit from step 3 with deionized water and anhydrous ethanol three times in sequence.

[0054] In some embodiments, the uranium oxide deposit described in step 3 is washed and then dried in a vacuum drying oven to obtain UO2 powder.

[0055] In some embodiments, the vacuum drying oven is set to 40-60°C and the drying time is 2-4 hours.

[0056] In some embodiments, the preparation method further includes purifying the uranium oxide deposit collected in step 3. Purification is a process of removing various impurities from the uranium oxide deposit through a series of physical, chemical, or electrochemical methods to improve its purity and bring it up to the standards for a specific application. Purification can be performed using methods known in the art. Exemplarily, purification can be carried out by dissolution and reprecipitation, electrochemical refining, solvent extraction, or ion exchange.

[0057] In some embodiments, the preparation method further includes concentrating the uranium-containing solution after completing steps 1-3 and then repeating steps 1-3.

[0058] The following is in conjunction with the appendix Figure 1 An electrolysis apparatus according to one embodiment of this application is illustrated by way of example.

[0059] In some implementations, reference Figure 1 The electrolysis device includes an electrolytic cell 2, a reference electrode 3, an anode 4, an ultrasonic transducer 5, a cathode rod / plate 6, a collection basket 7, an electrolysis control system 8, and an ultrasonic control system 9.

[0060] In this embodiment, the electrolytic cell 2 is used to hold the electrolyte 1, for example, the electrolyte is a uranium-containing solution.

[0061] In this embodiment, the reference electrode 3, anode 4, and cathode rod / plate 6 are disposed on an electrode holder, allowing them to be suspended within the electrolytic cell 2 without contacting the cell wall. The reference electrode 3, anode 4, and cathode rod / plate 6 are at least partially immersed in the electrolyte 1. The anode 4, cathode rod / plate 6, and electrolyte 1 constitute an electrical circuit. The cathode rod / plate 6 serves as the working electrode, undergoing a reduction reaction to generate UO2; the anode 4 undergoes an oxidation reaction, providing electrons required for the electrochemical reaction; the reference electrode 3 is used to monitor the potential difference between the reference electrode and the working electrode, stabilizing the potential of the working electrode within the target reaction potential range, thereby suppressing side reactions, improving electrolysis efficiency, and increasing product purity.

[0062] The reference electrode 3, anode 4, and cathode rod / plate 6 are electrically connected to the electrolysis control system 8.

[0063] For example, the reference electrode 3, anode 4, and cathode rod / plate 6 can be electrically connected to the electrolysis control system 8 via conductive wires. The electrolysis control system 8 is used to provide the voltage and current required for the electrochemical reaction. By setting and monitoring electrolysis parameters such as voltage and current in real time, and adjusting the electrolysis parameters through a data feedback system, the rate and stability of the electrolysis reaction can be effectively controlled.

[0064] In this embodiment, the ultrasonic transducer 5 is directly fixed to the upper end of the cathode rod / plate 6. The ultrasonic transducer 5 converts high-frequency ultrasonic electrical signals into high-frequency vibrations, converting electrical energy into mechanical energy. The cathode rod / plate 6 is the end-conduction device for ultrasonic waves and also the working electrode for the electrolytic reaction. The cathode rod / plate 6 directly transmits ultrasonic vibrations to the electrolyte. Through ultrasonic vibration, cavitation and acoustic flow effects are generated, enhancing the mass transfer efficiency of reactants in the electrolyte and reducing deposits and bubbles on the electrode surface.

[0065] In this embodiment, the ultrasonic transducer 5 is electrically connected to the ultrasonic control system 9.

[0066] For example, the ultrasonic transducer 5 can be electrically connected to the ultrasonic control system 9 via a conductive wire. The ultrasonic control system 9 is used to emit ultrasonic electrical signals and control the synergistic effect of electrolytic treatment and ultrasonic treatment by setting and monitoring the frequency and power of the ultrasonic waves in real time.

[0067] In this embodiment, the collection basket 7 and the electrolytic cell 2 are connected and interconnected via pipes to achieve the discharge and circulation of the solution within the collection basket 7 and the electrolytic cell 2, and to collect the generated UO2 deposits. The generated UO2 deposits can be guided to the collection basket 7 along with the liquid. The waste liquid after separating the UO2 deposits is concentrated and then used as a uranium-containing solution as an electrolyte, which is then piped back into the electrolytic cell 2.

[0068] In some embodiments, the device and its control system can be used to achieve semi-automatic or fully automated operation. During electrolysis, the electrolysis control system can acquire and analyze current-time or potential-time characteristic curves. When it detects that the operating current has naturally decayed and reached a preset low concentration threshold, it automatically reduces the electrochemical driving force of the cathode and switches to a lower constant current that matches the current mass transfer rate. This maximizes current efficiency and system energy consumption ratio while suppressing side reactions such as hydrogen evolution. The electrolysis control system also analyzes real-time current data to quantify the uranium reduction rate in real time and determine the degree of cathode passivation caused by the product UO2 coverage. The ultrasonic control system can monitor current decay or cathode potential exceeding limits caused by deposit coverage and automatically trigger ultrasonic vibration to achieve immediate stripping of the passivation layer on the electrode surface. At the same time, sensors can be set on the electrode and in the electrolyte to monitor parameters such as electrode passivation degree, electrolyte pH, and temperature. The control system adjusts voltage, current, and ultrasonic parameters to ensure the stability of the reaction environment and the visualization of the product recovery process.

[0069] The present application will be described in further detail below with reference to specific embodiments. The purpose of this description is merely illustrative and not intended to limit the scope of this disclosure.

[0070] Example

[0071] Example 1: Laboratory-scale uranium extraction verification test

[0072] (1) Prepare the electrolysis apparatus: such as Figure 1 As shown, a 2000mL polytetrafluoroethylene-lined electrolytic cell 2 is selected. The cathode 6 is a titanium rod, with a 20kHz, 300W ultrasonic transducer 5 mounted on top. The anode 3 is a 10mm diameter zinc rod, and the reference electrode 4 is a saturated calomel electrode. The three electrodes are fixed in an electrode support, with a 50mm distance between the cathode and anode.

[0073] (2) Preparation of electrolyte: Weigh 42.4g of uranyl nitrate (UO2(NO3)2·6H2O), dissolve it in 1000mL of dilute nitric acid solution adjusted to pH 4.0, to obtain UO2 2+ Electrolyte 1 with a concentration of 400 mg / L was used to maintain UO2. 2+The stability of uranium-containing solutions is understood to be strictly controlled due to their radioactivity. Therefore, this application uses the above method to prepare a simulated solution to simulate the state of uranium in spent fuel reprocessing liquids from nuclear facilities.

[0074] (3) Electrolysis and ultrasonic treatment: The electrolysis control system 8 is set to constant potential mode with a potential of +0.3V (vs standard hydrogen electrode) and a total deposition time of 60 minutes. The ultrasonic control system 9 applies periodic pulses to the ultrasonic transducer 5, turning on for 10 seconds and off for 5 seconds, with an ultrasonic power of 200W and a frequency of 25kHz.

[0075] (4) Sediment Collection and Treatment: After desorption by ultrasonic vibration, the sediment was suspended in the solution and guided to collection basket 7 by the fluid. The powder was separated by static sedimentation. The sediment was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 60°C for 4 hours. The resulting dark brown sediment was identified as UO2 by XRD analysis. The tailings were sampled and analyzed, and the residual uranium concentration was found to be 20 ppm. The total uranium recovery rate was approximately 95% (recovery rate (%) = [(initial concentration - residual concentration) / initial concentration] × 100%).

[0076] (5) Product characterization: Particle size analysis showed that the average particle size of the uranium oxide product was 170 nm, with the particle size distribution mainly concentrated in the 80-240 nm range, exhibiting good monodispersity. Figure 2 As shown.

[0077] Example 2: Uranium Extraction Experiment from Low-Concentration Uranium-Containing Aqueous Solution

[0078] (1) Preparation of electrolysis apparatus: A polytetrafluoroethylene-lined electrolytic cell 2 with a volume of 4000 mL is selected. The cathode 6 is a titanium rod, with a 20kHz ultrasonic transducer 5 with a rated power of 300W at the top. The anode 3 is a graphite rod with a diameter of 10mm. The two electrodes are fixed in the electrode support, and the electrode spacing is 20mm.

[0079] (2) Preparation of electrolyte: Use natural seawater with a uranium concentration of 40 ppm and a pH of 5.2 as the electrolyte.

[0080] (3) Electrolysis and ultrasonic treatment: The constant current pulse electrolysis mode is set through the electrolysis control system 8, and the current is set to 50mA / cm. 2 Electrolysis lasts for 60 seconds and is then turned off for 5 seconds. The ultrasonic control system 9 applies a periodic pulse mode to the ultrasonic transducer 5, turning it on for 5 seconds and off for 60 seconds. Electrolysis and ultrasound are applied alternately to the electrodes, and the total electrolysis deposition time is 6 hours.

[0081] (4) Sediment Collection and Treatment: After desorption by ultrasonic vibration, the sediment remained suspended in the solution and was guided by the fluid to a collection basket 7 equipped with a 0.2 μm filter membrane for UO2 particle filtration and collection. The sediment was washed three times sequentially with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 40°C for 2 hours. The resulting dark brown sediment was identified as UO2 by XRD analysis. Analysis of the treated tailings revealed a residual uranium concentration of 8 ppm. The overall uranium recovery rate was approximately 80%.

[0082] Example 3: Uranium Extraction Experiment from High-Concentration Uranium-Containing Aqueous Solution

[0083] (1) Preparation of the electrolysis apparatus: A system configuration similar to that in Example 1 was adopted. A stainless steel electrolytic cell 1 with a volume of 3000 mL was selected. The cathode 6 consisted of a stainless steel plate with a bottom width of 30 mm, a bottom width of 60 mm, and a height of 100 mm. A high-power ultrasonic transducer 5 with a rated power of 800 W and a frequency of 40 kHz was installed on the top. The anode 4 was selected as a graphite rod of the same length as the cathode to reduce costs and avoid introducing new metal ion contamination. The cathode and anode were placed in parallel with a spacing of 80 mm.

[0084] (2) Preparation of electrolyte: Take 2000 mL of process tail liquid from the uranium conversion plant as the treatment target, the main component of which is UO2. 2 + The initial concentration was determined to be 8500 ppm by ICP-MS. The pH of the solution was precisely adjusted to 3.5 using dilute sulfuric acid to ensure UO2. 2 + The solution remains stable during subsequent electrolysis. It represents typical uranium-containing industrial wastewater with high concentrations and strong acidity.

[0085] (3) Electrolysis and ultrasonic treatment: The electrolysis control system 8 is set to constant current mode with a current of 300 mA / cm2 to achieve rapid deposition. At the same time, the ultrasonic control system 9 is set to continuous ultrasonic mode, and the ultrasonic transducer works continuously throughout the electrolysis process. Due to the high solution concentration and high current density, the UO2 generation rate is extremely fast. The strong and continuous vibration of the continuous ultrasound can ensure that the generated UO2 deposits are stripped from the electrode surface immediately and without delay in the initial stage of their formation, effectively preventing any instantaneous passivation that may lead to a decrease in current efficiency.

[0086] (4) Sediment Collection and Analysis: After desorption by ultrasonic vibration, the sediments were suspended in the solution and guided by the fluid to a collection basket 7 equipped with a 0.5 μm filter membrane, achieving filtration and collection of UO2 sediment particles. After the experiment, the collected powder was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 40℃ for 2 hours. The treated tailings were sampled and analyzed, and the residual uranium concentration was found to be approximately 68 ppm. The total uranium recovery rate was approximately 99.2%.

[0087] The results above show that applying continuous or intermittent ultrasound during UO2 electrodeposition utilizes high-frequency ultrasonic vibration to promptly desorb the generated UO2 particles before the formation of their insulating layer, maintaining continuous exposure and reactivity of the cathode surface. This avoids the need to replace electrodes during continuous UO2 preparation, thus improving recovery efficiency. The total uranium recovery rate in Examples 1-3 is 80% or higher, demonstrating that by synergistically integrating ultrasonic energy continuously or intermittently with the electrolysis process, stable, continuous, and efficient extraction of UO2 powder from weakly acidic uranium-containing solutions is achieved. Furthermore, the UO2 particle size distribution diagram from Example 1 shows that intermittent ultrasonic treatment enables fine control of the deposit particle size. The UO2 particle size is mainly distributed in the 80-240 nm range, exhibiting good monodispersity.

[0088] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for extracting uranium oxide, characterized in that, The method includes: Step 1: Prepare an electrolysis apparatus, which includes an electrolytic cell, a cathode, an anode, and an ultrasonic transducer disposed on the cathode; Step 2: Place the uranium-containing solution in the electrolytic cell and perform ultrasonic-assisted electrolysis treatment, wherein the pH of the uranium-containing solution is 0-5.5; the voltage for ultrasonic-assisted electrolysis treatment is set to +0.32V-0V vs standard hydrogen electrode, and the current is set to 1-500mA / cm. 2 ; Step 3: Collect uranium oxide deposits.

2. The method according to claim 1, characterized in that, In step 2, the uranium-containing solution includes UO22. + Ions, the UO22 + The ion concentration is 50 ppb-10000 ppm.

3. The method according to claim 1 or 2, characterized in that, In step 2, the voltage of the ultrasonic-assisted electrolysis treatment remains constant.

4. The method according to claim 1 or 2, characterized in that, In step 2, the current for the ultrasonic-assisted electrolysis treatment remains constant.

5. The method according to claim 1 or 2, characterized in that, In step 2, the ultrasonic power of the ultrasonic-assisted electrolysis treatment is set to 30-1000W, and the ultrasonic frequency is set to 20-80kHz.

6. The method according to claim 5, characterized in that, The ultrasonic-assisted electrolysis treatment is configured to perform ultrasonic treatment and electrolysis treatment simultaneously.

7. The method according to claim 5, characterized in that, The ultrasonic-assisted electrolysis treatment is configured to alternate between ultrasonic treatment and electrolysis treatment, with the electrolysis treatment time period set to 1 min-30 min and the ultrasonic treatment time period set to 5 s-5 min.

8. The method according to claim 5, characterized in that, The ultrasonic-assisted electrolysis treatment is configured to be performed continuously, while the ultrasonic treatment is performed intermittently. The duration of the ultrasonic treatment is set to 5 seconds to 5 minutes, and the interval between ultrasonic treatments is set to 5 seconds to 30 minutes.

9. The method according to claim 1 or 2, characterized in that, The cathode is made of titanium or stainless steel.

10. The method according to claim 1 or 2, characterized in that, The distance between the cathode and the anode is set to 20-80 mm.

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