Vacuum hot reduction smelting device and method for rare earth metals

Abstract

The present application relates to the technical field of vacuum hot reduction smelting of rare earth metals, and discloses a device and a method for vacuum hot reduction smelting of rare earth metals. The device comprises a furnace body, a feeding system and a transition system. The furnace body comprises a smelting chamber and a crucible, and the crucible is provided with an opening at the bottom end. A plug is slidably arranged in the opening and is provided with a trigger for controlling the opening. A material loading platform is arranged below the crucible and is provided with a material receiving station. The feeding system comprises a feeding chamber and a hopper, and the feeding chamber is provided with a first communication port between the smelting chamber. The hopper is used for feeding raw materials into the crucible. The transition system comprises a transition chamber provided with a mold, and a second communication port is arranged between the transition chamber and the smelting chamber. A mold feeding device is used to drive the mold to transfer between the material receiving station and the transition chamber through the second communication port. The furnace body further comprises a first driving assembly for driving the mold to move in a first direction, so that the mold can abut against the trigger and drive the trigger to move. The continuous production of rare earth metals is realized, and the direct recovery rate of the metal is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum hot reduction smelting of rare earth metals, and particularly relates to a device and method for vacuum hot reduction smelting of rare earth metals. BACKGROUND

[0002] At present, the production of vacuum calcium hot reduction smelting of rare earth metals is usually carried out in a medium-frequency induction smelting furnace equipped with a tungsten crucible. The working process is as follows: after each furnace casting is completed, the furnace needs to be cooled to a specified time before being broken out of the vacuum; then the material is recharged, vacuum is extracted, and heating and reduction are performed, forming a cyclic production mode.

[0003] However, this production mode directly causes a low batch yield. Moreover, in the production process, the tungsten crucible will undergo sudden heating and sudden cooling, which seriously affects its service life and increases the production cost, and this factor further restricts the improvement of the batch yield. In addition, in the casting and cooling links, part of the metal particles cannot completely settle from the upper molten salt, affecting the direct recovery rate of the metal. SUMMARY

[0004] The present application provides a device for vacuum hot reduction smelting of rare earth metals to solve or improve the problems of low batch yield and low direct recovery rate of metal in the related art of vacuum calcium hot reduction smelting of rare earth metals.

[0005] In a first aspect, the present application provides a device for vacuum hot reduction smelting of rare earth metals, comprising a furnace body, a feeding system, and a transition system.

[0006] The furnace body comprises:

[0007] a smelting chamber and a crucible arranged in the smelting chamber, the bottom end of the crucible being provided with an opening;

[0008] a plug slidingly arranged in the opening, the plug being used to open or close the opening, and the plug being provided with a trigger member extending out of the opening;

[0009] a loading platform located below the crucible, the loading platform being provided with a material receiving station opposite to the opening;

[0010] The feeding system comprises a feeding chamber and a hopper arranged in the feeding chamber, a first communication port capable of being opened and closed being arranged between the feeding chamber and the smelting chamber, and the hopper being used to feed raw materials to the crucible;

[0011] The transition system comprises:

[0012] a transition chamber provided with a mold, and a second communication port capable of being opened and closed being arranged between the transition chamber and the smelting chamber;

[0013] A mold feeding device is configured to drive the mold to transfer between the receiving station and the transition chamber through the second communication port. The furnace body further comprises a first driving assembly arranged at the receiving station, and the first driving assembly is configured to drive the mold to move in a first direction so that the mold can abut against the trigger and drive the trigger to move.

[0014] In an alternative embodiment, the crucible comprises:

[0015] A main body portion, and a first heating coil is arranged around an outer wall of the main body portion;

[0016] A transition portion is arranged at a bottom end of the main body portion, and the transition portion is provided with the opening, and a second heating coil is arranged around an outer wall of the transition portion opposite to the plug position.

[0017] In an alternative embodiment, further comprising:

[0018] A counterweight is arranged on the trigger;

[0019] A dust shield is movably arranged on a side of the second communication port facing the smelting chamber in the first direction;

[0020] An observation window is arranged at a top of the smelting chamber.

[0021] In an alternative embodiment, further comprising:

[0022] A detection electrode is configured to detect a position of an interface between the molten metal and the molten salt in the crucible, and the detection electrode is electrically connected to the first driving assembly. The detection electrode is rotatably arranged in the smelting chamber and can move in the first direction. A rotation center of the detection electrode is arranged offset from a center of the crucible.

[0023] A second driving assembly is configured to drive the detection electrode to rotate and move in the first direction.

[0024] In an alternative embodiment, the mold comprises a water-cooled ingot mold and a casting mold arranged on the water-cooled ingot mold.

[0025] The mold feeding device comprises:

[0026] A moving trolley is configured to be supported on a bottom surface of the water-cooled ingot mold. The moving trolley is arranged to move along a track arranged on the object table and the transition chamber.

[0027] A third driving assembly is configured to drive the moving trolley to transfer between the receiving station and the transition chamber through the second communication port.

[0028] In an alternative embodiment, further comprising:

[0029] a first communication pipe, one end of which is in communication with the charging chamber and the other end of which is in communication with the melting chamber;

[0030] a first communication valve, which is arranged on the first communication pipe and is used to control the opening and closing of the first communication pipe;

[0031] a second communication pipe, one end of which is in communication with the transition chamber and the other end of which is in communication with the melting chamber;

[0032] a second communication valve, which is arranged on the second communication pipe and is used to control the opening and closing of the second communication pipe.

[0033] In an alternative embodiment, the hopper is movably arranged in the charging chamber and is capable of moving in the first direction;

[0034] The charging system further comprises a fourth driving assembly, which is used to drive the hopper to move in the first direction and to move the hopper between the charging chamber and the melting chamber through the first communication opening.

[0035] In an alternative embodiment, the charging system further comprises:

[0036] a charging box, in which the hopper is movably arranged, and the fourth driving assembly is arranged on the charging box;

[0037] a transition flange, which is in communication with and separable from the charging box, the interior of the charging box and the transition flange together form the charging chamber, and the first communication opening is arranged between the transition flange and the melting chamber;

[0038] a fifth driving assembly, which is connected with the charging box and is used to drive the charging box to move in the first direction so as to separate or engage the charging box and the transition flange.

[0039] In an alternative embodiment, further comprising:

[0040] a vacuumizing system, which is in communication with the charging chamber, the melting chamber and the transition chamber;

[0041] a first control valve, which is arranged between the charging chamber and the vacuumizing system and is used to control the opening and closing of the charging chamber and the vacuumizing system;

[0042] a second control valve, which is arranged between the transition chamber and the vacuumizing system and is used to control the opening and closing of the transition chamber and the vacuumizing system;

[0043] The first vent valve has one end connected to the outside and the other end connected to the feeding chamber. The first vent valve is used to control the connection between the feeding chamber and the outside.

[0044] The second vent valve has one end connected to the outside and the other end connected to the transition chamber. The second vent valve is used to control the connection between the transition chamber and the outside.

[0045] Secondly, the present invention also provides a method for vacuum thermal reduction smelting of rare earth metals, based on the rare earth metal vacuum thermal reduction smelting apparatus as described in any of the above claims, comprising the following steps:

[0046] The raw materials are placed in the crucible, and the charging chamber, melting chamber and transition chamber are evacuated. The first and second connecting ports are closed, and the mold is placed in the transition chamber.

[0047] When the first heating coil is energized, the crucible begins to heat up, and the raw materials inside the crucible react.

[0048] After the reaction is complete, the second connecting port and the dust baffle are opened, and the mold is transferred to the receiving station through the mold supply device. Then the second connecting port and the dust baffle are closed, the second heating coil is energized, and the mold is driven to move upward through the first driving component and push against the trigger of the plug, so that the plug moves upward, the opening is opened, and the molten metal is discharged into the mold through the opening.

[0049] After all the molten metal has been discharged, the mold is driven to move down to the receiving station by the first drive component. The plug moves under the action of gravity and re-seals the opening, and the second heating coil stops working.

[0050] Open the second connection port and transfer the mold from the receiving station to the transition chamber through the mold supply device;

[0051] Close the second connection port, remove the mold from the melting chamber from the transition chamber, replace it with a new mold, and then evacuate the transition chamber.

[0052] Open the first connection port and feed the raw material into the crucible through the feeding system. Then close the first connection port and repeat the above operation.

[0053] In one optional embodiment, after all the molten metal has been discharged, the mold is driven to move to the receiving station by the first lifting device, the plug moves under gravity and re-seals the opening, and the second heating coil stops working, including:

[0054] The probe electrode is inserted into the crucible to detect the interface between the molten metal and the molten salt. After all the molten metal is discharged, the probe electrode sends a signal. The first drive assembly receives the signal from the probe electrode and drives the mold to move down to the receiving station. The plug moves under gravity and re-seals the opening, and the second heating coil stops working.

[0055] The present invention has the following beneficial technical effects:

[0056] 1. The rare earth metal vacuum thermal reduction melting apparatus provided by this invention allows the feeding chamber, melting chamber, and transition chamber to form independent sealed chambers by opening and closing two connecting ports. After the raw materials in the crucible have reacted, due to the density difference, the upper layer is molten salt and the lower layer is liquid metal. The first driving component drives the mold to push against the trigger in the first direction, driving the plug to move upward, opening the opening, and draining the lower layer of liquid metal into the mold. After all the liquid metal has been drained, the mold is driven to move downward, closing the plug and opening the opening. Then, the mold is removed by the mold supply device, the second connecting port is closed, and a new mold is replaced to perform vacuum treatment on the transition chamber. Then, the new mold is moved to the receiving station, and the raw materials are replenished by the feeding system for secondary melting. After sufficient reaction, the above operation is repeated to drain all the liquid and prepare for the next preparation. By repeating this process, continuous production of rare earth metals can be achieved without having to break the vacuum in the melting chamber before opening the lid to add material, thus saving operation time, improving production efficiency and capacity, and achieving energy saving. The crucible does not need to undergo repeated rapid heating and cooling, reducing production costs. Moreover, after the first melting, the mold is basically filled with pure metal, and after the second melting, the mold is basically filled with molten salt, with a small amount of rare earth metal settling at the bottom, which can effectively improve the direct metal recovery rate.

[0057] In addition, it should be noted that the rare earth metals prepared by this device have low calcium and oxygen content, which can meet the technical requirements for direct shipment and reduce the adverse effects of increased oxygen content caused by traditional secondary refining.

[0058] 2. By adding a second heating coil to heat the opening at the bottom of the crucible, it is possible to ensure that the molten metal remains in a liquid state and avoid the problem of the plug being unable to be opened due to the molten metal at the opening cooling and solidifying.

[0059] 3. Adding counterweights can improve the success rate of plug closure and ensure reliable operation of the device. Furthermore, dust baffles can prevent fumes generated during the reaction from spreading to the second connection port and transition chamber.

[0060] 4. By setting a detection electrode to detect the interface position between the molten metal and the molten salt in the crucible, the timing of closing the plug opening and de-energizing the second heating coil can be accurately controlled. Furthermore, the detection electrode 112 can rotate and lift, which can avoid interference between the liquid level detection operation and the feeding operation. Attached Figure Description

[0061] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0062] Figure 1 This is a schematic diagram of the structure of a rare earth metal vacuum thermal reduction smelting apparatus according to an embodiment of the present invention;

[0063] Figure 2 This is a partial schematic diagram of the furnace body and transition system according to an embodiment of the present invention;

[0064] Figure 3 This is a partial schematic diagram of the crucible according to an embodiment of the present invention;

[0065] Figure 4 This is a partial schematic diagram of the feeding system according to an embodiment of the present invention.

[0066] Explanation of reference numerals in the attached figures:

[0067] 1. Furnace body; 101. Melting chamber; 102. Crucible; 1021. Main body; 1022. Transition section; 103. Plug; 104. Trigger; 105. Stage; 106. First drive assembly; 1061. Support platform; 1062. Lead screw; 107. First heating coil; 108. Second heating coil; 109. Counterweight; 110. Dust baffle; 111. Observation window; 112. Detector electrode; 113. Second drive assembly; 114. Thermal insulation layer;

[0068] 2. Feeding system; 201. Feeding chamber; 202. Hopper; 203. Fourth drive assembly; 204. Feeding box; 205. Transition flange; 206. Fifth drive assembly; 207. First control valve; 208. First vent valve; 209. Baffle plate;

[0069] 3. Transition system; 301. Transition chamber; 302. Mold; 3021. Water-cooled ingot mold; 3022. Casting mold; 303. Mold supply device; 3031. Moving trolley; 3032. Third drive assembly; 30321. Push rod; 30322. Flexible traction component; 304. Second control valve; 305. Second venting valve;

[0070] 4. First connecting port; 5. Second connecting port; 6. First connecting pipeline; 7. First connecting valve; 8. Second connecting pipeline; 9. Second connecting valve; 10. First isolation valve; 11. Second isolation valve. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0074] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0075] The following is combined Figures 1 to 4 This invention describes a rare earth metal vacuum thermal reduction smelting apparatus and method according to embodiments of the present invention.

[0076] According to embodiments of the present invention, in one aspect, a vacuum thermal reduction smelting apparatus for rare earth metals is provided, comprising a furnace body 1, a feeding system 2, and a transition system 3. Specifically, as... Figure 1 As shown, the furnace body 1 includes a melting chamber 101, a crucible 102, a plug 103, and a platform 105. The crucible 102 is disposed in the melting chamber 101, and has an opening at its bottom end. The plug 103 is slidably disposed in the opening and is used to open or close the opening. The plug 103 is provided with a trigger 104 extending out of the opening, which may be a striking pin. The platform 105 is located below the crucible 102 and has a receiving station opposite the opening.

[0077] The feeding system 2 includes a feeding chamber 201 and a hopper 202 disposed within the feeding chamber 201. A first connecting port 4, which can be opened and closed, is provided between the feeding chamber 201 and the melting chamber 101. Specifically, a first isolation valve 10, such as a vacuum gate valve, can be used to control the opening and closing of the first connecting port 4. The hopper 202 is used to feed raw materials into the crucible 102. Specifically, the raw materials can be rare earth fluoride and a certain proportion of reducing agent metallic calcium, and rare earth metals are extracted through calcium thermal reduction.

[0078] The transition system 3 includes a transition chamber 301 and a mold supply device 303. The transition chamber 301 is equipped with a mold 302. A second connecting port 5, which can be opened and closed, is provided between the transition chamber 301 and the melting chamber 101. Specifically, a second isolation valve 11, such as a vacuum gate valve, can be used to control the opening and closing of the second connecting port 5. The mold supply device 303 is used to drive the mold 302 to transfer between the receiving station and the transition chamber 301 through the second connecting port 5. The furnace body 1 also includes a first drive assembly 106 disposed at the receiving station. The first drive assembly 106 is used to drive the mold 302 to move along a first direction so that the mold 302 can abut against the trigger 104 and drive the trigger 104 to move, thereby driving the plug 103 to move up and down. The operation is convenient and it is easy to reasonably control the opening and closing timing of the plug 103. Specifically, the first drive assembly 106 can adopt a motor + screw nut mechanism, such as... Figure 2 As shown, the assembly includes a support platform 1061 and a lead screw 1062 threadedly connected to the support platform 1061. A platform 105 has a clearance hole for the support platform 1061 to pass through, and a mold 302 is located on the support platform 1061. A motor drives the lead screw 1062 to rotate, thereby moving the support platform 1061 up and down in a first direction, which in turn drives the mold 302 to move up and down, thus driving the plug 103 to move up and down. Alternatively, the first drive assembly 106 can also employ other linear drive mechanisms such as a cylinder.

[0079] With this configuration, the feeding chamber 201, the melting chamber 101, and the transition chamber 301 can form independent, sealed chambers by opening and closing the two connecting ports. First, rare earth fluoride and the theoretically proportioned reducing agent, metallic calcium, are placed in crucible 102. After the raw materials in crucible 102 have reacted, due to the density difference, the upper layer is molten salt and the lower layer is liquid metal. The first driving component 106 drives the mold 302 to push against the trigger 104 in the first direction, driving the plug 103 to move upward, opening the opening, and draining the lower layer of liquid metal into the mold 302. After all the liquid metal is drained, the mold 302 is driven to move downward, and the plug 103 closes the opening. Then, the mold 302 is removed by the mold supply device 303, the second connecting port 5 is closed, and a new mold 302 is replaced. The transition chamber 301 is then vacuum-treated. The new mold 302 is then moved to the receiving station, and the raw materials are replenished using the feeding system 2. The remaining proportion of reducing agent, metallic calcium, is added for secondary smelting. After sufficient reaction, the above operation is repeated, all liquid is drained, and preparation is made for the next rare earth metal refining. By repeating this process, continuous production of rare earth metals can be achieved without cooling and breaking the vacuum in the melting chamber 101 before opening the lid and adding materials. This saves operating time, improves production efficiency and capacity, and achieves energy-saving effects. The crucible does not need to undergo repeated rapid heating and cooling, reducing production costs. Moreover, after the first melting, the mold 302 is basically pure metal and is a low-calcium, low-oxygen product, which can directly meet customer product requirements. After the second melting, the mold 302 is basically molten salt with a small amount of rare earth metal settling at the bottom, which can effectively improve the direct metal recovery rate.

[0080] It should be noted that the rare earth metals prepared by this device generally have low calcium and oxygen content, meeting the technical requirements for direct shipment and reducing the adverse effects of increased oxygen content caused by traditional secondary refining. To further verify the application effect of this device, the following detailed description is provided with reference to specific embodiments: various rare earth metals were prepared using the preparation process of this device and the conventional secondary refining process, and the calcium and oxygen content in the products were tested and compared.

[0081] Example 1

[0082] Using metallic terbium as the target material, the preparation process of this embodiment and the conventional secondary refining process were used for production. The comparison results of the calcium and oxygen content of the metallic terbium obtained under the two processes, as well as the comparison data of the total metal direct recovery rate and the unit power consumption of the product, are detailed in Table 1.

[0083]

[0084] Table 1 compares the calcium and oxygen content in metallic terbium obtained under different preparation methods, as well as the total metal recovery rate and unit power consumption.

[0085] Example 2

[0086] Using metallic gadolinium as the preparation target, both the preparation process of this embodiment and the conventional secondary refining process were employed for production. The comparison results of the calcium and oxygen content of the metallic gadolinium obtained under the two processes, as well as the comparison data of the total metal direct recovery rate and the unit power consumption of the product, are detailed in Table 2.

[0087]

[0088] Table 2 compares the calcium and oxygen content in gadolinium metal obtained under different preparation methods, as well as the total metal recovery rate and unit power consumption.

[0089] Example 3

[0090] Using metallic dysprosium as the target material, both the preparation process of this embodiment and the conventional secondary refining process were employed for production. The comparison results of the calcium and oxygen content of the metallic dysprosium obtained under the two processes, as well as the comparison data of the total metal recovery rate and the unit power consumption of the product, are detailed in Table 3.

[0091]

[0092] Table 3 compares the calcium and oxygen content in dysprosium obtained under different preparation methods, as well as the total metal recovery rate and unit power consumption.

[0093] This demonstrates that the rare earth metals prepared using this device can have their calcium and oxygen impurity content mostly controlled at low levels, meeting the technical standards for direct delivery and effectively avoiding the technical drawbacks of traditional secondary refining processes that easily lead to increased oxygen content. Furthermore, the preparation process using the device in this embodiment results in a higher overall metal recovery rate and lower production energy consumption, significantly improving production efficiency and overall benefits.

[0094] Optionally, in some embodiments of the present invention, such as Figure 3 As shown, the crucible 102 includes a main body 1021 and a transition portion 1022 disposed at the bottom end of the main body 1021. A first heating coil 107 is disposed around the outer wall of the main body 1021. The transition portion 1022 has an opening, and a second heating coil 108 is disposed around the outer wall of the transition portion 1022, opposite to the position of the plug 103. The heating coil may be an induction coil, and a heat-insulating layer 114 is provided between the heating coil and the crucible 102.

[0095] With this setup, the first heating coil 107 is energized to heat the raw materials in the crucible 102, allowing them to fully react and generate molten calcium fluoride and liquid metal. After the reaction is complete, the second heating coil 108 is energized, and then the mold 302 lifts the trigger 104, moving it upwards along with the plug 103, allowing the liquid metal to leak out from the opening. Heating the opening with the second heating coil 108 ensures that the liquid metal remains in a liquid state, preventing the plug 103 from failing to open due to the liquid metal cooling and solidifying at the opening.

[0096] Optionally, in some embodiments of the present invention, the smelting apparatus further includes a counterweight 109, which is disposed on the trigger 104, thereby improving the success rate of closing the plug 103 and ensuring reliable operation of the apparatus.

[0097] The smelting apparatus also includes a dust baffle 110, which is movably disposed along the first direction on the side of the second connecting port 5 facing the smelting chamber 101. This dust baffle 110 can block the smoke and dust generated by the reduction reaction in the smelting chamber 101, prevent the smoke and dust from falling at the second connecting port 5 and affecting the sealing performance of the second connecting port 5, and prevent the smoke and dust from diffusing into the transition chamber 301. Furthermore, by moving the dust baffle 110 up and down, it can avoid hindering the transfer of the mold 302.

[0098] The smelting apparatus also includes an observation window 111, which is located on the top of the smelting chamber 101, so as to make it easy to intuitively view the process of the calcium thermal reduction reaction in the smelting chamber 101 and monitor the reaction dynamics in real time.

[0099] Optionally, in some embodiments of the present invention, the smelting apparatus further includes a detection electrode 112 and a second driving assembly 113. The detection electrode 112 is used to detect the interface position between the molten metal and the molten salt in the crucible 102, and the detection electrode 112 is electrically connected to the first driving assembly 106. In use, the detection electrode 112 is immersed in the lower part of the crucible 102 (without contacting the crucible 102). Since the conductivity of the molten metal and the molten salt is different, the electrical signal fed back by the detection electrode 112 can accurately determine the interface position between the molten metal and the molten salt, thereby accurately controlling the timing of closing the opening of the plug 103 and de-energizing the second heating coil 108, ensuring that after the molten metal is discharged, what remains in the crucible 102 is basically molten salt. Specifically, taking the first driving component 106 driven by a motor as an example, the detection electrode 112 is typically composed of a metal probe. When the high-temperature liquid in the crucible 102 contacts the electrode, the conductive liquid connects the circuit to form a closed loop. Due to the different conductivity of the molten metal and the molten salt, when the liquid contacted by the detection electrode 112 changes from molten metal to molten salt, the resistance between the electrodes changes, thereby detecting an electrical signal. This electrical signal is captured instantly and sent to the controller. The controller receives the electrical signal and outputs a control command to the motor according to preset logic. The motor drives the lead screw 1062 to rotate according to the control command, thereby driving the mold 302 to move downwards, so that the plug 103 moves downwards to close the opening. Similarly, when the controller receives the electrical signal emitted by the detection electrode 112, it can output a control command to the second heating coil 108 to control the second heating coil 108 to be de-energized.

[0100] like Figure 3 As shown, the detection electrode 112 is rotatably disposed in the melting chamber 101 and can move along a first direction. The rotation center of the detection electrode 112 is offset from the center of the crucible 102, with a certain eccentricity L between them. The second drive assembly 113 is used to drive the detection electrode 112 to rotate and move along the first direction. Specifically, the second drive assembly 113 includes a linear motor and a servo motor. The linear motor is used to drive the detection electrode 112 to move up and down along the first direction, so that the detection electrode 112 can extend into and retract from the crucible 102. The linear motor is rotatably mounted on the top of the furnace body 1 and connected to the servo motor. The servo motor can drive the linear motor to rotate, rotating together with the detection electrode 112, so that after the detection electrode 112 retracts from the crucible 102, it can rotate at a certain angle to avoid interference between the liquid level detection operation and the feeding operation in the crucible 102. In addition, the second drive assembly 113 can adopt other rotary lifting mechanisms, such as a motor driving a turntable to rotate, with the linear motor mounted on the turntable, thereby realizing the rotation and lifting action of the detection electrode 112.

[0101] Optionally, in some embodiments of the present invention, the mold 302 includes a water-cooled ingot mold 3021 and a casting mold 3022 disposed on the water-cooled ingot mold 3021, thereby realizing the casting and cooling of metal. The mold supply device 303 includes a moving trolley 3031 and a third drive assembly 3032. The moving trolley 3031 is used to support the bottom surface of the water-cooled ingot mold 3021. The platform 105 and the transition chamber 301 are provided with tracks. The moving trolley 3031 travels along the tracks so that the moving trolley 3031 runs stably along a predetermined path, thereby driving the mold 302 to move directly below the crucible 102. The third drive assembly 3032 is used to drive the moving trolley 3031 to transfer between the receiving station and the transition chamber 301 through the second communication port 5, thereby facilitating the removal of the refined metal from the smelting chamber 101 and the removal of the mold 302 from the transition chamber, realizing continuous production of rare earth metals with convenient operation. Specifically, the tracks of the platform 105 and the transition chamber 301 are disconnected to avoid affecting the opening and closing of the second connecting port 5. The bottom of the mobile trolley 3031 is equipped with multiple sets of wheels, each set consisting of two wheels. The distance between the two wheels should be greater than the distance between the disconnected tracks of the platform 105 and the transition chamber 301, ensuring that each set of wheels maintains contact with the tracks on both sides of the second connecting port 5 when the mobile trolley 3031 passes through the second connecting port 5, ensuring a smooth transition. Optionally, the third drive assembly 3032 includes a push rod 30321 and a flexible traction member 30322. Specifically, the push rod 30321 can be detachably connected to the mobile trolley 3031, for example, by hooking or hanging rings. The push rod 30321 can be driven by a motor, electric telescopic rod, etc., to move linearly. The flexible traction component 30322 can be a flexible cable, chain, etc. One end of the flexible traction component 30322 is connected to the moving trolley 3031, and the other end is wound on a winding mechanism located on the inner wall of the transition chamber 301 for winding the flexible traction component 30322. Specifically, the push rod 30321 drives the moving trolley 3031 and the mold 302 to move laterally in one direction, pushing them from the transition chamber 301 to the receiving station, and then the push rod 30321 automatically resets. After the metal casting is completed, the flexible traction component 30322 pulls the moving trolley 3031 and the mold 302 back to the transition chamber 301. In addition, the third drive assembly 3032 can also adopt other linear drive mechanisms such as cylinders.

[0102] Optionally, in some embodiments of the present invention, the smelting apparatus further includes a first connecting pipe 6, a first connecting valve 7, a second connecting pipe 8, and a second connecting valve 9. Specifically, one end of the first connecting pipe 6 is connected to the feeding chamber 201, and the other end is connected to the smelting chamber 101. The first connecting valve 7 is disposed on the first connecting pipe 6 and is used to control the opening and closing of the first connecting pipe 6, thereby connecting the feeding chamber 201 and the smelting chamber 101 according to actual usage requirements, so that the pressure of the two is kept consistent, facilitating the feeding operation. One end of the second connecting pipe 8 is connected to the transition chamber 301, and the other end is connected to the smelting chamber 101. The second connecting valve 9 is disposed on the second connecting pipe 8 and is used to control the opening and closing of the second connecting pipe 8, thereby connecting the transition chamber 301 and the smelting chamber 101 according to actual usage requirements, so that the pressure of the two is kept consistent, facilitating the mold transfer operation.

[0103] Optionally, in some embodiments of the present invention, the hopper 202 is movably disposed within the feeding chamber 201 and is capable of moving along a first direction. The feeding system 2 further includes a fourth drive assembly 203, which drives the hopper 202 to move along the first direction and causes the hopper 202 to move between the feeding chamber 201 and the melting chamber 101 through the first communication port 4. Optionally, as Figure 4 As shown, multiple baffles 209 are rotatably connected to the bottom of the hopper 202. The bottom ends of each baffle 209 can be secured with plastic cable ties to ensure that the raw material does not leak out. The fourth drive assembly 203 includes a linear motor connected to the hopper 202. The linear motor drives the hopper 202 to move downwards and extend into the crucible 102. The temperature inside the crucible 102 is high enough to melt the plastic cable ties. Under the action of gravity, the raw material pushes open the baffles 209 and falls into the crucible 102. After feeding is completed, the motor drives the hopper 202 to move upwards and return to the feeding chamber 201, thereby enabling more accurate and convenient feeding operations and avoiding material waste. In addition, the fourth drive assembly 203 can also adopt other drive mechanisms such as electric cylinders and electric telescopic rods.

[0104] Optionally, in some embodiments of the present invention, such as Figure 4As shown, the feeding system 2 also includes a feeding box 204, a transition flange 205, and a fifth drive assembly 206. The hopper 202 is movably disposed within the feeding box 204, and the fourth drive assembly 203 is disposed on the feeding box 204. The transition flange 205 is connected to and detachable from the feeding box 204; it is important to ensure a sealed connection at their joint. The interiors of the feeding box 204 and the transition flange 205 together form the feeding chamber 201, and a first communication port 4 is provided between the transition flange 205 and the melting chamber 101. The fifth drive assembly 206 is connected to the feeding box 204 and is used to drive the feeding box 204 to move along a first direction, thereby separating or engaging the feeding box 204 and the transition flange 205. Specifically, the fifth drive assembly 206 can be a jack, which drives the feeding box 204 to move up and down. Alternatively, the fifth drive assembly 206 can also be a cylinder or other drive mechanism. Thus, when raw materials need to be added to the hopper 202, the fifth drive assembly 206 drives the feeding box 204 to move upward, and the hopper 202 moves downward to extend out of the feeding box 204 for raw material feeding. Then, the hopper 202 moves upward to reset, and the fifth drive assembly 206 drives the feeding box 204 to move downward again, re-fitting tightly with the transition flange 205, thereby facilitating the feeding of raw materials into the feeding system 2. It should be noted that the first connecting port 4 should be closed when feeding raw materials into the feeding system 2.

[0105] Optionally, in some embodiments of the present invention, the smelting apparatus further includes a vacuum system, a first control valve 207, a first venting valve 208, a second control valve 304, and a second venting valve 305. The vacuum system is connected to the feeding chamber 201, the smelting chamber 101, and the transition chamber 301, thereby performing vacuum treatment on each chamber. The first control valve 207 is disposed between the feeding chamber 201 and the vacuum system, and is used to control the connection and disconnection between the feeding chamber 201 and the vacuum system. One end of the first venting valve 208 is connected to the outside, and the other end is connected to the feeding chamber 201, and is used to control the connection and disconnection between the feeding chamber 201 and the outside. Thus, the feeding system 2 can be vacuumed and devastated as needed. The second control valve 304 is disposed between the transition chamber 301 and the vacuum system, and is used to control the connection and disconnection between the transition chamber 301 and the vacuum system. The second vent valve 305 is connected to the outside at one end and to the transition chamber 301 at the other end. The second vent valve 305 is used to control the connection between the transition chamber 301 and the outside. Thus, the transition system 3 can be evacuated and de-vacuumed as needed.

[0106] According to an embodiment of the present invention, in another aspect, a method for vacuum thermal reduction smelting of rare earth metals is also provided, based on the rare earth metal vacuum thermal reduction smelting apparatus as described in the above embodiments, comprising the following steps:

[0107] The raw materials are placed in the crucible 102, and the feeding chamber 201, melting chamber 101 and transition chamber 301 are evacuated. The first connecting port 4 and the second connecting port 5 are closed. The mold 302 is placed in the transition chamber 301.

[0108] When the first heating coil 107 is energized, the crucible 102 begins to heat up, and the raw materials inside the crucible 102 react.

[0109] After the reaction is complete, the second connecting port 5 and the dust baffle 110 are opened, and the mold 302 is transferred to the receiving station through the mold supply device 303. Then the second connecting port 5 and the dust baffle 110 are closed, the second heating coil 108 is energized, and the mold 302 is driven to move upward through the first lifting device and push against the trigger 104 of the plug 103, so that the plug 103 moves upward, the opening is opened, and the molten metal is discharged into the mold 302 through the opening.

[0110] After all the molten metal is discharged, the mold 302 is driven to move down to the receiving station by the first lifting device, the plug 103 moves under the action of gravity and re-seals the opening, and the second heating coil 108 stops working.

[0111] Open the second connecting port 5 and transfer the mold 302 from the receiving station to the transition chamber 301 through the mold supply device 303;

[0112] Close the second connecting port 5, remove the mold 302 from the melting chamber 101 from the transition chamber 301, replace it with a new mold 302, and then evacuate the transition chamber 301.

[0113] Open the first connecting port 4 and add raw materials into the crucible 102 through the feeding system 2. Then close the first connecting port 4 and repeat the above operation. It should be noted that rare earth fluoride and the theoretical proportion of reducing agent metallic calcium are first put into the crucible 102 for a first melting. After the raw materials in the crucible 102 have reacted, all the molten metal is discharged. After the first melting, the mold 302 is basically pure metal and is a low-calcium, low-oxygen product, which can directly meet the customer's product requirements and meet the technical requirements for direct delivery. Then, the raw materials are replenished using the feeding system 2, and the remaining proportion of reducing agent metallic calcium is added for a second melting. After sufficient reaction, all the liquid is discharged. After the second melting, the mold 302 is basically molten salt with a small amount of metal settling at the bottom. At this time, the calcium content in the metal is relatively high. After separation, it can be refined together with the metal from other furnaces to meet the customer's requirements. The derivation process of this beneficial effect is roughly similar to the derivation process of the beneficial effect of the above rare earth metal vacuum thermal reduction melting device, so it will not be repeated here.

[0114] Optionally, in some embodiments of the present invention, the steps include: after all the molten metal has been discharged, the mold 302 is driven to move down to the receiving station by the first driving component 106, the plug 103 moves under gravity and re-seals the opening, and the second heating coil 108 stops working.

[0115] The probe electrode 112 is inserted into the crucible 102 to detect the interface between the molten metal and the molten salt in the crucible 102. After all the molten metal is discharged, the probe electrode 112 sends a signal. The first drive assembly 106 receives the signal from the probe electrode 112 and drives the mold 302 to move down to the receiving station. The plug 103 moves under the action of gravity and re-seals the opening. The second heating coil 108 stops working.

[0116] It should be noted that the electrical signal fed back by the detection electrode 112 can accurately determine the interface position between the molten metal and the molten salt, thereby accurately controlling the timing of closing the opening of the plug 103 and de-energizing the second heating coil 108, ensuring that after the molten metal is discharged, what remains in the crucible 102 is basically molten salt.

[0117] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A vacuum thermal reduction smelting apparatus for rare earth metals, characterized in that, It includes the furnace body (1), the feeding system (2), and the transition system (3); The furnace body (1) includes: A melting chamber (101) and a crucible (102) disposed in the melting chamber (101), the crucible (102) having an opening at its bottom end; A plug (103) is slidably disposed in the opening. The plug (103) is used to open or close the opening. The plug (103) is provided with a trigger (104) extending out of the opening. A stage (105) is located below the crucible (102), and the stage (105) is provided with a receiving station opposite to the opening; The detection electrode (112) is used to detect the interface position between the molten metal and the molten salt in the crucible (102); The feeding system (2) includes a feeding chamber (201) and a hopper (202) disposed in the feeding chamber (201). A first connecting port (4) that can be opened and closed is provided between the feeding chamber (201) and the melting chamber (101). The hopper (202) is used to feed raw materials into the crucible (102). The transition system (3) includes: The transition chamber (301) is equipped with a mold (302), and a second connecting port (5) that can be opened and closed is provided between the transition chamber (301) and the melting chamber (101). A mold supply device (303) is used to drive the mold (302) to transfer between the receiving station and the transition chamber (301) through the second communication port (5). The furnace body (1) also includes a first drive assembly (106) disposed at the receiving station. The detection electrode (112) is electrically connected to the first drive assembly (106). The first drive assembly (106) is used to drive the mold (302) to move along a first direction so that the mold (302) can abut against the trigger (104) and drive the trigger (104) to move.

2. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 1, characterized in that, The crucible (102) includes: The main body (1021) has a first heating coil (107) arranged around its outer wall. A transition section (1022) is provided at the bottom end of the main body (1021). The transition section (1022) is provided with the opening. A second heating coil (108) is provided around the outer wall of the transition section (1022) and is positioned opposite to the plug (103).

3. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 2, characterized in that, Also includes: A counterweight (109) is disposed on the trigger (104); A dust baffle (110) is movably disposed along the first direction on the side of the second communication port (5) facing the melting chamber (101); An observation window (111) is provided at the top of the smelting chamber (101).

4. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 3, characterized in that, The detection electrode (112) is rotatably disposed in the melting chamber (101) and can move along the first direction. The rotation center of the detection electrode (112) is offset from the center of the crucible (102). The rare earth metal vacuum thermal reduction smelting apparatus further includes a second driving component (113), which is used to drive the detection electrode (112) to rotate and move along the first direction.

5. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 3, characterized in that, The mold (302) includes a water-cooled ingot mold (3021) and a casting mold (3022) disposed on the water-cooled ingot mold (3021). The mold supply device (303) includes: A mobile trolley (3031) is used to support the bottom surface of the water-cooled ingot mold (3021). The platform (105) and the transition chamber (301) are provided with tracks, and the mobile trolley (3031) travels along the tracks. The third drive assembly (3032) is used to drive the mobile trolley (3031) to transfer between the receiving station and the transition chamber (301) through the second communication port (5).

6. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 3, characterized in that, Also includes: The first connecting pipe (6) is connected at one end to the feeding chamber (201) and at the other end to the smelting chamber (101); The first connecting valve (7) is installed on the first connecting pipeline (6), and the first connecting valve (7) is used to control the opening and closing of the first connecting pipeline (6); The second connecting pipe (8) is connected at one end to the transition chamber (301) and at the other end to the smelting chamber (101); The second connecting valve (9) is installed on the second connecting pipeline (8) and is used to control the opening and closing of the second connecting pipeline (8).

7. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 3, characterized in that, The hopper (202) is movably disposed within the feeding chamber (201) and is capable of moving along the first direction; The feeding system (2) further includes a fourth drive component (203) for driving the hopper (202) to move along the first direction and for moving the hopper (202) between the feeding chamber (201) and the melting chamber (101) through the first communication port (4).

8. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 7, characterized in that, The feeding system (2) also includes: A feeding box (204) is provided, wherein the hopper (202) is movably disposed within the feeding box (204), and the fourth drive assembly (203) is disposed on the feeding box (204); A transition flange (205) is connected to and separated from the feeding box (204). The interiors of the feeding box (204) and the transition flange (205) together form the feeding chamber (201), and the first communication port (4) is provided between the transition flange (205) and the melting chamber (101). A fifth drive assembly (206) is connected to the feeding box (204) and is used to drive the feeding box (204) to move along the first direction so that the feeding box (204) and the transition flange (205) are separated or engaged.

9. The rare earth metal vacuum thermal reduction smelting apparatus according to claim 3, characterized in that, Also includes: A vacuum system is connected to the feeding chamber (201), the melting chamber (101), and the transition chamber (301); A first control valve (207) is disposed between the feeding chamber (201) and the vacuum system. The first control valve (207) is used to control the opening and closing of the feeding chamber (201) and the vacuum system. A second control valve (304) is disposed between the transition chamber (301) and the vacuum system. The second control valve (304) is used to control the opening and closing of the transition chamber (301) and the vacuum system. The first vent valve (208) is connected to the outside at one end and to the feeding chamber (201) at the other end. The first vent valve (208) is used to control the connection and disconnection between the feeding chamber (201) and the outside. The second vent valve (305) is connected to the outside at one end and to the transition chamber (301) at the other end. The second vent valve (305) is used to control the connection and disconnection between the transition chamber (301) and the outside.

10. A method for vacuum thermal reduction smelting of rare earth metals, characterized in that, The rare earth metal vacuum thermal reduction smelting apparatus based on any one of claims 3 to 9 includes the following steps: The raw materials are placed in the crucible (102), and the charging chamber (201), melting chamber (101) and transition chamber (301) are evacuated. The first connecting port (4) and the second connecting port (5) are closed. The mold (302) is placed in the transition chamber (301). When the first heating coil (107) is energized, the crucible (102) begins to heat up, and the raw materials inside the crucible (102) react. After the reaction is complete, the second connecting port (5) and the dust baffle (110) are opened, and the mold (302) is transferred to the receiving station through the mold supply device (303). Then the second connecting port (5) and the dust baffle (110) are closed, and the second heating coil (108) is energized. The first driving component (106) drives the mold (302) to move upward and push against the trigger (104) of the plug (103), so that the plug (103) moves upward, the opening is opened, and the molten metal is discharged into the mold (302) through the opening. After all the molten metal is discharged, the mold (302) is driven to move down to the receiving station by the first drive assembly (106), the plug (103) moves under the action of gravity and re-seals the opening, and the second heating coil (108) stops working. Open the second connecting port (5) and transfer the mold (302) from the receiving station to the transition chamber (301) through the mold supply device (303). Close the second connecting port (5), remove the mold (302) from the melting chamber (101) from the transition chamber (301), replace it with a new mold (302), and then evacuate the transition chamber (301); Open the first connection port (4), feed the raw material into the crucible (102) through the feeding system (2), and then close the first connection port (4).

11. The vacuum thermal reduction smelting method for rare earth metals according to claim 10, characterized in that, After all the molten metal has been discharged, the first driving assembly (106) drives the mold (302) to move down to the receiving station, the plug (103) moves under gravity and re-seals the opening, and the second heating coil (108) stops working, including: The probe electrode (112) is inserted into the crucible (102) to detect the interface between the molten metal and the molten salt in the crucible (102). After all the molten metal is discharged, the probe electrode (112) sends a signal. The first drive assembly (106) receives the signal from the probe electrode (112) and drives the mold (302) to move down to the receiving station. The plug (103) moves under the action of gravity and re-seals the opening. The second heating coil (108) stops working.

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