Rare earth molten salt electrolysis device and electrolysis method

Abstract

The invention discloses a rare earth molten salt electrolysis device which comprises an anode conducting rod, and the anode conducting rod is in an L shape and has the functions of conducting electricity and introducing ultrasonic waves; the upper end of the ultrasonic guide rod is connected with the L-shaped anode conducting rod; the ultrasonic transducer is connected to the other end of the ultrasonic guide rod; the ultrasonic generator is connected with the ultrasonic transducer; the high-temperature-resistant soft isolation material is arranged between the anode conducting rod and the electrolytic bath body; according to the scheme, ultrasonic waves are directionally guided into the surface of the anode, so that an air film on the surface of the anode is rapidly broken and released into electrolyte, discharge of bubbles released into the electrolyte is accelerated, and the carbon content in rare earth metal or alloy is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rare earth electrolysis, in particular to a rare earth molten salt electrolysis device and an electrolysis method. BACKGROUND

[0002] In the process of producing praseodymium-neodymium alloy by rare earth molten salt electrolysis, due to the use of oxide-fluoride molten salt electrolysis method and graphite as anode and electrolytic cell, the content of carbon impurities is too high, and at the same time, a gas film is formed on the surface of the anode, which affects the conductivity efficiency of the electrolytic cell and also causes pressure drop of the gas film, thereby increasing the electrolysis voltage, and further affecting the current efficiency of the electrolytic cell and the metal unit consumption, and finally affecting the quality of rare earth metal products and the economic and technical indicators of the electrolytic cell, so there is room for improvement.

[0003] Therefore, the present application provides a rare earth molten salt electrolysis device and an electrolysis method SUMMARY

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows: A rare earth molten salt electrolysis device, comprising: A graphite tank body; An anode system comprising an anode conductive rod, an anode guide rod and a high-temperature-resistant soft insulation material, the anode conductive rod is arranged on the graphite tank body, the anode conductive rod is in an "L" shape and comprises a horizontal segment and a vertical segment, the anode guide rod is arranged at one end of the horizontal segment of the anode conductive rod and vertically arranged in the graphite tank body, and the high-temperature-resistant soft insulation material is arranged between the graphite tank body and the horizontal segment of the anode conductive rod; A cathode system comprising a cathode guide rod arranged in the graphite tank body; An ultrasonic system comprising an ultrasonic transducer connected to the upper end of the vertical segment of the anode conductive rod and an ultrasonic generator connected to the ultrasonic transducer.

[0005] According to an embodiment of the present application, the anode conductive rod is in a split structure.

[0006] According to an embodiment of the present application, the anode conductive rod is fixedly connected with the anode guide rod by welding.

[0007] According to an embodiment of the present application, the high-temperature-resistant soft insulation material is formed by stacking multiple layers of flexible mica sheets.

[0008] The second aspect of the present application provides a rare earth molten salt electrolysis method, which is applied to the rare earth molten salt electrolysis device, and the rare earth molten salt electrolysis method comprises: S101. Adding solid electrolyte into the graphite tank body; S102. The cathode guide rod is vertically fixed at a distance of 5-10 cm from the bottom of the graphite tank body; S103. The anode conductive rod is sealed and installed at the top of the graphite tank body by high-temperature-resistant soft material, and the lower end surface of the anode conductive rod is at a distance of 5-10 cm from the bottom of the graphite tank body, and the ultrasonic transducer is fixed on the upper end of the vertical section of the anode conductive rod; S104. The graphite tank body is heated to above the melting point of the electrolyte by an external heating system until the solid-state electrolyte is completely melted to form a conductive electrolyte; S105. The positive electrode on the anode guide rod and the negative electrode on the cathode guide rod are connected, the initial current is set to 500-20,000 A, and direct current is input to start electrolysis, and the chemical reaction equation is as follows: Cathode: 2RE 3+ +6e - =RE(s); Anode: 3O 2- -6e - +3C=3CO(g); Where RE is a rare earth element; s is solid; g is gaseous; S106. Direct current is input, and the ultrasonic generator is turned on to drive the ultrasonic transducer to produce mechanical vibration, which is conducted through the anode conductive rod to the anode guide rod and finally to the electrolyte through the anode guide rod; S107. After a period of time of continuously inputting current and applying ultrasonic waves, the input of current is stopped, the ultrasonic generator is turned off, and the rare earth metal is obtained from the bottom of the graphite tank body.

[0009] According to an embodiment of the present application, the ultrasonic generator is set to an ultrasonic frequency of 20-30 kHz and an ultrasonic power of 1-20 kW.

[0010] According to an embodiment of the present application, during the electrolysis process, the connection part of the ultrasonic transducer and the anode conductive rod is checked for looseness every 4-6 hours, and if it is loose, it is tightened.

[0011] According to an embodiment of the present application, after each electrolysis is completed, the electrolyte residue attached to the surface of the anode guide rod is cleaned, and the damaged high-temperature-resistant soft insulation material is replaced.

[0012] The rare earth molten salt electrolysis device according to the embodiment of the present application is provided with the anode conductive rod, the L-shaped anode conductive rod is in the L shape and is in conduction with the ultrasonic transducer, the electric energy is converted into mechanical energy, and the mechanical vibration is transmitted to the anode conductive rod through the anode conductive rod. In the high-temperature environment, the ultrasonic wave is directed to the surface of the anode, so as to reduce the area and thickness of the gas film formed on the surface of the anode. The gas film formed on the surface of the anode is broken quickly by the ultrasonic wave, and is released into the electrolyte. At the same time, the ultrasonic wave vibration on the surface of the anode is also transmitted to the interface between the anode and the electrolyte, so as to accelerate the discharge of the gas bubbles released into the electrolyte under the vibration of the ultrasonic wave. That is, the gas film on the surface of the anode is destroyed by the vibration of the ultrasonic wave, and is quickly released into the electrolyte, so as to reduce the area and thickness of the gas film on the surface of the anode; the ultrasonic wave is transmitted to the interface between the anode and the electrolyte, so as to accelerate the discharge of the gas bubbles released into the electrolyte under the vibration of the ultrasonic wave, reduce the residence time of the gas bubbles in the electrolyte, reduce the contact probability of the gas bubbles with the rare earth metal in the cathode area, and significantly reduce the carbon content in the alloy metal.

[0013] Additional aspects and advantages of the present application will be better understood from the following description in conjunction with the accompanying drawings. Descriptions of specific embodiments of the present application are included for purposes of illustration. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the application and are incorporated herein for reference. The illustrative embodiments of the present application and their description serve to explain the application. In the drawings:

[0015] Fig. 1 is a structural schematic diagram of a rare earth molten salt electrolysis device according to an embodiment of the present application; Fig. 2 is a graph showing the change of the carbon content in the rare earth metal after the reaction of CO and the rare earth metal according to the present application; Fig. 3 is a flow chart of a rare earth molten salt electrolysis method according to the present application.

[0016] Reference Signs List: 1, graphite tank body; 2, tungsten-made metal receiver; 3, cathode conductive rod; 4, anode conductive rod; 5, high-temperature-resistant soft insulation material; 6, anode conductive rod; 7, ultrasonic transducer; 8, ultrasonic generator. DETAILED DESCRIPTION

[0017] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0018] As shown in Figs. 1-3 , the present application provides a rare earth molten salt electrolysis device, which comprises a graphite tank body 1, an anode conductive rod 6, a high-temperature-resistant soft insulation material 5, an ultrasonic transducer 7 and an ultrasonic generator 8.

[0019] Anode conducting rod 6 is provided on the graphite tank 1, and the anode conducting rod 6 is in "L" shape, which is used for conducting electricity and introducing ultrasonic waves. In order to form an anode circuit, so that the current can be conducted into the electrolyte, and maintain the electrolysis reaction, the anode conducting rod 6 is provided on the top of the graphite tank 1, so that the current can be conducted into the electrolyte. The anode conducting rod 6 is provided in L-shaped structure, so that the ultrasonic waves can be introduced into the electrolyte.

[0020] In order to avoid the short circuit between the graphite tank 1 and the anode conducting rod 6, and ensure that the current is conducted through the electrolyte. High-temperature-resistant soft insulation material 5 is provided between the graphite tank 1 and the anode conducting rod 6.

[0021] In order to convert electrical energy into mechanical vibration, the ultrasonic transducer 7 is connected to one end of the anode conducting rod 6, which is conducted to the electrolyte through the anode conducting rod 6, and directly acts on the anode area. The ultrasonic wave is excited near the anode area, which can destroy the gas film (such as CO bubble film) on the anode surface, reduce the shielding effect of gas adsorption on the current, and improve the current efficiency.

[0022] In order to quickly break the CO bubble film and release it into the electrolyte, and also to make the ultrasonic vibration on the anode surface transmit to the interface between the anode and the electrolyte, so that the gas bubbles released into the electrolyte can be accelerated to be discharged under the vibration of the ultrasonic wave. The ultrasonic generator 8 is connected with the ultrasonic transducer 7, which can provide continuous mechanical vibration, and the mechanical vibration can achieve the destruction of the gas film attached to the anode, and the discharge of the gas bubbles in the electrolyte, so as to improve the current efficiency. Therefore, the ultrasonic generator 8 is connected with the ultrasonic transducer 7, which can provide stable ultrasonic energy, continuous vibration to destroy the gas film, prevent the gas bubbles from gathering to form a continuous insulating layer, and ensure that the current uniformly passes through the electrolyte.

[0023] In order to form an anode circuit with the anode conducting rod 6, and ensure that the current is uniformly distributed, the graphite tank 1 and the anode conducting rod 6 are connected to define an electrolytic cell, which is used to contain the electrolyte.

[0024] In order to form an electrolysis circuit, the cathode conducting rod 3 is provided in the electrolytic cell, which is connected with the anode (i.e. the graphite tank 1, the anode conducting rod 6 and the anode conducting rod 4) to form a complete circuit.

[0025] In order to strengthen the anode structure, and also to cooperate with the ultrasonic wave, the anode conducting rod 4 is provided on the horizontal section of the anode conducting rod 6, and is vertically arranged in the graphite tank 1.

[0026] In the electrolysis process, the ultrasonic wave is generated by the ultrasonic generator 8, converted by the ultrasonic transducer 7 into mechanical vibration, and then transmitted to the "L"-shaped anode conducting rod 6, so that the ultrasonic wave is directed to the surface of the anode conducting rod 4, the gas film on the surface of the anode is quickly broken and released into the electrolyte, and the gas bubbles released into the electrolyte are accelerated to be discharged, so as to reduce the carbon content in the rare earth metal or alloy and improve the economic and technical indicators of the electrolytic cell.

[0027] According to the rare earth molten salt electrolysis device, the L-shaped anode conducting rod is in the "L" shape and is in conduction with the ultrasonic transducer, the electrical energy is converted into mechanical energy, and the mechanical vibration is transmitted to the anode conducting rod through the anode conducting rod. In the high-temperature environment, the ultrasonic wave is directed to the surface of the anode, so as to reduce the area and thickness of the gas film on the surface of the anode. The gas film formed on the surface of the anode is quickly broken and released into the electrolyte through the micro-vibration of the ultrasonic wave. At the same time, the ultrasonic vibration on the surface of the anode is also transmitted to the interface between the anode and the electrolyte, so that the gas bubbles released into the electrolyte are accelerated to be discharged under the vibration of the ultrasonic wave. That is, the gas film on the surface of the anode is destroyed by the vibration of the ultrasonic wave and quickly released into the electrolyte, so as to reduce the area and thickness of the gas film on the surface of the anode; the ultrasonic wave is transmitted through the interface between the anode and the electrolyte, so that the gas bubbles released into the electrolyte are quickly discharged outward under the action of the ultrasonic vibration, the residence time of the gas bubbles in the electrolyte is reduced, the contact probability of the gas bubbles with the rare earth metal in the cathode area is reduced, and the carbon content in the alloy metal is significantly reduced.

[0028] According to an embodiment of the present application, in order to ensure that the upper space structure of the electrolytic cell is not cramped, the anode conducting rod 6 is split type, which is convenient to install and disassemble.

[0029] According to an embodiment of the present application, in order to ensure that the upper space structure of the electrolytic cell is not cramped, the anode conducting rod 6 is split type, which is convenient to install and disassemble.

[0030] According to an embodiment of the present application, in order to isolate the graphite tank body 1 and the anode conducting rod 6 and avoid short circuit, the high-temperature-resistant soft insulation material 5 is formed by stacking multiple flexible mica sheets, the flexible stacking can fill irregular gaps, improve the sealing performance, and prevent electrolyte leakage or gas infiltration.

[0031] According to an embodiment of the present application, the rare earth molten salt electrolysis device further comprises a tungsten metal receiver 2 arranged in the graphite tank body 1, which is used to receive the rare earth metal generated by the cathode, such as lanthanum, cerium, praseodymium and neodymium.

[0032] A second aspect of the present invention provides a rare earth molten salt electrolysis method, which is applied to the rare earth molten salt electrolysis device, comprising: a graphite tank body 1; an anode conductive rod 6, which is arranged on the graphite tank body 1 and is "L"-shaped; a high-temperature resistant soft insulating material 5, which is arranged between the graphite tank body 1 and the anode conductive rod 6; an ultrasonic transducer 7, which is connected to one end of the anode conductive rod 6; and an ultrasonic generator 8, which is connected to the ultrasonic transducer 7; wherein the graphite tank body 1 and the anode conductive rod 6 are connected to define an electrolytic cell, which is used to accommodate an electrolyte; a cathode guide rod 3, which is arranged in the electrolytic cell; and an anode guide rod 4, which is arranged on the anode conductive rod 6. The rare earth molten salt electrolysis method comprises: S101. Add solid electrolyte to the electrolytic cell.

[0033] In the rare earth molten salt electrolysis process, the electrolyte used is a fluoride system, generally composed of approximately 85% rare earth fluoride and 15% lithium fluoride. For the electrolysis of single rare earth metals such as lanthanum, cerium, praseodymium, and neodymium, the electrolytes used are LaF3-LiF, CeF3-LiF, PrF3-LiF, and NdF3-LiF, respectively. For the production of rare earth alloys, such as PrNdGd alloy, PrNdF3-GdF3-LiF is used; for Y-Mg alloy, YF3-LiF is generally used. Lithium fluoride acts as a flux, lowering the melting point of the rare earth fluoride and improving the electrolyte's conductivity and fluidity, thereby optimizing the electrolysis process.

[0034] S102. Vertically secure the cathode guide rod 3 to the center of the electrolytic cell, 5 to 10 cm from the cell bottom. Ensure that it is insulated from the graphite cell body 1. Because graphite is a conductor, if the cathode guide rod 3 directly contacts the graphite cell body 1, the current will bypass the electrolysis reaction, affecting electrolysis efficiency and equipment safety.

[0035] S103. The anode conductive rod 6 is sealed and installed on the top of the graphite tank body 1 through the high-temperature resistant soft insulating material 5. The lower end face of the anode conductive rod 6 is 5 cm to 10 cm away from the bottom of the electrolytic cell. The ultrasonic transducer 7 is fixed to the upper end of the vertical section of the anode conductive rod 6.

[0036] S104. Heat the electrolytic cell to above the melting point of the electrolyte through an external heating system and maintain it for 30 minutes until the solid electrolyte is completely melted to form a conductive electrolyte; the external heating system is not limited by the present invention and can be a resistance furnace or other heating system.

[0037] S105. Connect the positive electrode on the anode guide rod 4 and the negative electrode on the cathode guide rod 3, set the initial current to 500A ~ 20000A, and start electrolysis by applying direct current; the chemical reaction equation is as follows: Cathode: 2RE3+ +6e - =RE(s); Anode: 3O 2- -6e - +3C=3CO(g).

[0038] Here RE stands for rare earth element, which is finally precipitated in the form of solid metal element (s stands for solid).

[0039] Rare earth metals include lanthanum (La), cerium (Ce), praseodymium (Pr) and neodymium (Nd).

[0040] S106. After direct current is supplied, the ultrasonic generator 8 is turned on to drive the ultrasonic transducer 7 to generate mechanical vibration. The mechanical vibration is transmitted to the anode guide rod 4 through the anode conductive rod 6 and finally to the electrolyte.

[0041] S107. After continuously supplying current and applying ultrasonic waves for a period of time, stop supplying current, turn off the ultrasonic generator 8, and obtain rare earth metals from the bottom of the electrolytic cell. The rare earth metals include lanthanum, cerium, praseodymium, neodymium, and rare earth alloys prepared by molten salt electrolysis.

[0042] Electrolytes for single rare earth metals: For the electrolysis of four single rare earth metals, lanthanum (La), cerium (Ce), praseodymium (Pr) and neodymium (Nd), specific electrolyte systems are used: Electrolytic lanthanum: LaF3-LiF system is used. LaF3 is used as the source of lanthanum ions (La). During the electrolysis process, La obtains electrons at the cathode to generate metallic lanthanum (La). The reaction formula is 2La 3+ +6e - =2La(s); LiF plays a fluxing role, lowering the melting point of LaF3, allowing electrolysis to proceed at a relatively low temperature.

[0043] Electrolytic cerium: CeF3-LiF system is used. The principle is similar to that of electrolytic lanthanum. CeF3 provides cerium ions (Ce), and 2Ce is generated at the cathode. 3+ +6e¯=2Ce(s) reaction, generating metallic cerium, and LiF assists in lowering the melting point.

[0044] Electrolytic praseodymium: using PrF3-LiF system. PrF3 provides Pr 3+ , cathode reaction 2Pr 3+ +6e - =2Pr(s), achieving the precipitation of praseodymium metal, and LiF improving the electrolyte performance.

[0045] Electrolytic neodymium: using NdF3~LiF system. NdF3 provides Nd 3+ , cathode passes 2Nd3+ +6e - =2Nd(s) Reaction to obtain metal neodymium, LiF play flux effect.

[0046] Electrolyte for producing rare earth alloy: Production of PrNdGd alloy: using PrNdF3~GdF3~LiF system. In this system, PrNdF3 provides praseodymium ions (Pr 3 + ) and neodymium ions (Nd 3+ ), GdF3 provides gadolinium ions (Gd + ). In the electrolysis process, these ions are simultaneously reduced at the cathode, precipitate and fuse according to the set ratio, forming PrNdGd alloy. LiF also plays a fluxing and improving electrolyte properties role, ensuring the smooth progress of the electrolysis reaction.

[0047] Production of Y-Mg alloy: generally using YF3-LiF system. YF3 provides yttrium ions (Y 3+ ), and at the cathode Y is reduced to form yttrium metal, while other components in the system or process conditions promote magnesium elements to also participate in the reaction, ultimately forming Y-Mg alloy, and LiF assists in completing the entire electrolysis process.

[0048] The ultrasonic generator 8 sets the ultrasonic frequency at 20 kHz-30 kHz, and the ultrasonic power at 1 kW-20 kW.

[0049] In some embodiments, during the electrolysis process, the connection part of the ultrasonic transducer 7 and the anode conducting rod 6 is checked every 4-6 hours to see if it is loose, and if it is loose, it is tightened.

[0050] In some embodiments, after each electrolysis is completed, the electrolyte residue attached to the surface of the anode guide rod 4 is cleaned, and the damaged high-temperature-resistant soft insulation material 5 is replaced.

[0051] The anode conducting rod 6 conducts current and introduces ultrasonic waves through the "L" structure, the ultrasonic transducer 7 converts electrical energy into mechanical vibration, which acts on the electrolyte through the anode guide rod 4, destroys the gas film (such as the insulating layer formed by CO bubbles) on the surface of the anode, reduces the current resistance to improve efficiency, and at the same time suppresses the contact between CO and rare earth to reduce carbon pollution; The high-temperature-resistant soft insulation material 5 between the graphite tank body 1 and the anode conducting rod 6 ensures insulation, the cathode conducting rod 3 and the anode form a complete electrolysis loop, and each component is designed to cooperate with the conducting and vibrating functions to achieve the purpose of reducing carbon content, destroying the gas film and improving current efficiency.

[0052] Comparative example: Maximum current of 400A rare earth molten salt electrolysis cell device and analysis results of electrolysis products The 400A rare earth molten salt electrolytic cell generally adopts external heating, does not have an independent anode, and the graphite crucible serves as the anode. The rectifier is normally turned on, and the feeding is performed according to a preset feeding system. The electrolysis is performed in a constant voltage mode, the voltage is adjusted to 5.5V, and the current fluctuates between 300A and 330A. The experimental results are shown in Table 1.

[0053] Table 1: Electrolysis experimental results of the 400A rare earth molten salt electrolytic cell Example 1 The ultrasonic wave assisted rare earth molten salt electrolytic cell device with a maximum current of 400A and the electrolysis product analysis results.

[0054] The 400A rare earth molten salt electrolytic cell generally adopts external heating, the ultrasonic wave is introduced into the anode of the electrolytic cell by using an ultrasonic wave introduction device, and the electrolysis is started. The electrolysis is performed in a constant voltage mode, the voltage is adjusted to 5.6V, the current fluctuates between 300A and 320A, the ultrasonic wave frequency is set to 21kHz, and the ultrasonic wave power is 15kW. The experimental results are shown in Table 2.

[0055] Table 2: Electrolysis experimental results of the 400A ultrasonic wave assisted rare earth molten salt electrolytic cell Example 2 The ultrasonic wave assisted rare earth molten salt electrolytic cell device with a maximum current of 3000A and the electrolysis product analysis results.

[0056] The 3000A rare earth molten salt electrolytic cell generally adopts a self-heating electrolytic cell, and does not need to provide external heat. The anode conductive rod 6 and the ultrasonic wave transducer 7 of the present application are connected, as shown in Fig. 1 The electrolysis is started. The electrolysis is performed in a constant voltage mode, the voltage is adjusted to 8.3V, the current fluctuates between 2800A and 3000A, the ultrasonic wave frequency is set to 23kHz, and the ultrasonic wave power is 15kW. The experimental results are shown in Table 3.

[0057] Table 3: Electrolysis experimental results of the 3000A ultrasonic wave assisted rare earth molten salt electrolytic cell Through comparative analysis of the data of the three experimental tables (400A conventional rare earth molten salt electrolysis, 400A ultrasonic wave assisted rare earth molten salt electrolysis, and 3000A ultrasonic wave assisted rare earth molten salt electrolysis), the following conclusions can be drawn: Effect of ultrasonic wave on reducing metal carbon content 400A Ultrasonic-Assisted Rare Earth Molten Salt Electrolyzer: In a conventional 400A rare earth molten salt electrolyzer, the voltage was 5.5V, the current fluctuated between 300A and 330A, and without ultrasonic assistance, the metal carbon content was between 0.021% and 0.032%. With ultrasonic assistance, the voltage was adjusted to 5.6V, the current fluctuated between 300A and 320A, and the ultrasonic frequency was 21kHz, and the metal carbon content dropped to 0.016% to 0.021%.

[0058] This shows that ultrasound destroys the anode gas film, causing the gas film to disperse quickly into the electrolyte, reducing the area and thickness of the gas film on the anode surface, and at the same time prompting the bubbles dispersed in the electrolyte to be quickly discharged outward under ultrasonic vibration, reducing the probability of contact between the bubbles and the rare earth metals in the cathode area, thereby effectively reducing the metal carbon content.

[0059] 3000A Electrolyzer: This 3000A ultrasonic-assisted rare earth molten salt electrolyzer is self-heating, operates at 8.3V, current fluctuates between 2800A and 3000A, ultrasonic frequency is 23kHz, and power is 15kW. The metal carbon content ranges from 0.011% to 0.018%. Compared to the 400A ultrasonic-assisted rare earth molten salt electrolyzer, ultrasound still reduces the metal carbon content at higher currents, further demonstrating the significant effect of ultrasound on reducing metal carbon content in electrolyzers of varying sizes by improving the anode gas film and accelerating bubble expulsion.

[0060] Effect of Ultrasonic Waves on Current Efficiency 400A electrolyzer: The current efficiency of the 400A conventional electrolyzer ranged from 78.47% to 83.71%, while the current efficiency of the 400A ultrasonic-assisted electrolyzer ranged from 82.44% to 88.87%. This indicates that ultrasonic assistance improves current efficiency because it disrupts the anode gas membrane, reduces anode polarization, and optimizes the electrolysis reaction kinetics, enabling more efficient electrolysis.

[0061] 3000A Electrolyzer: The 3000A ultrasonic-assisted electrolyzer achieved a current efficiency between 81.50% and 90.40%. Under large-scale, self-heating electrolysis conditions, the integration of ultrasound and the electrolyzer optimized the electrolysis process and improved energy efficiency, demonstrating the positive role of ultrasound assistance in improving current efficiency in large-scale production.

[0062] In general, in rare earth molten salt electrolytic cells of different sizes, by setting ultrasonic parameters (frequency, power, etc.) and utilizing the mechanism of ultrasonic waves to destroy the anode gas film and accelerate the discharge of bubbles, it is possible to effectively reduce the metal carbon content, improve the purity of rare earth metal products, and improve current efficiency.

[0063] like Fig. 2As shown, a molybdenum crucible is placed at the bottom of a graphite tank (1) and a certain amount of electrolyte is placed above it. The crucible is placed in a resistance furnace and heated until the metal and electrolyte are completely melted. CO gas is introduced into the electrolyte to simulate the CO generated during actual production, causing it to be suspended in the electrolyte. After different time intervals, the rare earth metal at the bottom is sampled and analyzed for carbon content.

[0064] like Fig. 2 As shown, the horizontal axis is the time axis, and the vertical axis is the carbon content in the metal. Fig. 2 As can be seen from the figure, when CO gas is introduced into the electrolyte, it comes into contact with the rare earth metals at the bottom of the electrolytic cell and reacts with them. Over time, the probability of contact between CO and the rare earth metals increases, causing the carbon content in the rare earth metals to rise. This indicates that in actual production, anode gas is a significant contributor to the increase in carbon content in the metals. This also confirms that accelerating anode gas discharge through ultrasound can help reduce the carbon content in rare earth metals.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0066] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0067] In the description of the specification, reference to "one embodiment", "some embodiments", "an exemplary embodiment", "an example", "a specific example" or "some examples" means that a particular feature, structure, material or characteristic is included in at least one embodiment or example of the present application. The appearances of the phrases "in one embodiment", "in some embodiments", "in an exemplary embodiment", "an example", "a specific example" or "some examples" in various places in the specification are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0068] The above descriptions are only the preferred embodiment of the application, not intended to limit the application and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A rare earth molten salt electrolysis device, characterized in that: include: Graphite tank (1): An anode system comprises an anode conductive rod (6), an anode guide rod (4) and a high-temperature resistant soft insulating material (5), wherein the anode conductive rod (6) is arranged on a graphite tank body (1), the anode conductive rod (6) is "L"-shaped and comprises a horizontal section and a vertical section, the anode guide rod (4) is arranged at one end of the horizontal section of the anode conductive rod (6) and is vertically arranged in the graphite tank body (1), and the high-temperature resistant soft insulating material (5) is arranged between the graphite tank body (1) and the horizontal section of the anode conductive rod (6); A cathode system, comprising a cathode guide rod (3), arranged in the graphite tank body (1); The ultrasonic system comprises an ultrasonic transducer (7) and an ultrasonic generator (8), wherein the ultrasonic transducer (7) is connected to the upper end of the vertical section of the anode conductive rod (6), and the ultrasonic generator (8) is connected to the ultrasonic transducer (7).

2. The rare earth molten salt electrolysis device according to claim 1, characterized in that: The anode conductive rod (6) is a split structure.

3. The rare earth molten salt electrolysis device according to claim 1, characterized in that: The anode conductive rod (6) is fixedly connected to the anode guide rod (4) by welding.

4. The rare earth molten salt electrolysis device according to claim 1, characterized in that: The high-temperature resistant soft insulating material (5) is formed by stacking multiple layers of flexible mica sheets.

5. A rare earth molten salt electrolysis method, characterized in that: The method is applied to the rare earth molten salt electrolysis device according to claim 1, and the rare earth molten salt electrolysis method comprises: S101. Adding a solid electrolyte to the graphite tank (1); S102. Fix the cathode guide rod (3) vertically to the center of the graphite tank (1) at a distance of 5cm to 10cm from the bottom of the tank; S103. The anode conductive rod (6) is sealed with a high-temperature resistant soft material and mounted on the top of the graphite tank (1). The lower end surface of the anode guide rod (4) is 5 cm to 10 cm away from the bottom of the graphite tank (1). The ultrasonic transducer (7) is fixed to the upper end of the vertical section of the anode conductive rod (6); S104. The graphite tank (1) is heated to above the melting point of the electrolyte by an external heating system until the solid electrolyte is completely melted to form a conductive electrolyte; S105. Connect the positive electrode on the anode guide rod (4) and the negative electrode on the cathode guide rod (3), set the initial current to 500A to 20000A, and start electrolysis by applying direct current. The chemical reaction equation is as follows: Cathode: 2RE 3+ +6e - =RE(s); Anode: 3O 2- -6e - +3C=3CO(g); Where RE is a rare earth element; s is solid; g is gaseous; S106. Direct current is supplied to turn on the ultrasonic generator (8), driving the ultrasonic transducer (7) to generate mechanical vibration, which is transmitted through the anode conductive rod (6) to the anode guide rod (4), and then finally transmitted to the electrolyte through the anode guide rod (4); S107. After continuously supplying current and applying ultrasonic waves for a period of time, stop supplying current, turn off the ultrasonic generator (8), and obtain rare earth metals from the bottom of the graphite tank (1).

6. The rare earth molten salt electrolysis method according to claim 5, characterized in that: The ultrasonic generator (8) is set to have an ultrasonic frequency of 20 kHz to 30 kHz and an ultrasonic power of 1 kW to 20 kW.

7. The rare earth molten salt electrolysis method according to claim 5, characterized in that: During the electrolysis process, the connection between the ultrasonic transducer (7) and the anode conductive rod (6) is checked every 4 to 6 hours to see if it is loose. If so, tighten it.

8. The rare earth molten salt electrolysis method according to claim 5, characterized in that: After each electrolysis, the electrolyte residue attached to the surface of the anode guide rod (4) is cleaned and the damaged high-temperature resistant soft insulating material (5) is replaced.

Images