A rare earth metal suction casting system and method

Abstract

The present application relates to the field of rare earth electrolytic ingot preparation, and discloses a rare earth metal suction casting system and method, which comprises a rack, an overflow cavity, a suction pipe, a mold bin and a negative pressure device. The suction pipe is a vertical pipe without bending, the lower end of which extends into the metal liquid in a containing vessel, and the upper end of which is in communication with the overflow cavity fixed to the rack; the side wall of the overflow cavity is provided with an overflow port extending into the mold bin, and the ingot mold is arranged below the overflow port. The metal liquid is sucked into the overflow cavity through the vertical suction pipe by the negative pressure device, and when the liquid level exceeds the overflow port, the metal liquid is smoothly introduced into the ingot mold in a gravity overflow mode. The method utilizes the overflow cavity to realize pressure release, avoids the direct impact of negative pressure on the ingot mold, and enables the metal liquid to cool and solidify in a static state, thereby fundamentally solving the problems of ingot burr and metal and molten salt hybridization caused by the traditional bending pipe suction casting method. Meanwhile, the vertical suction pipe structure enables the metal liquid to automatically return by gravity, thereby eliminating the phenomenon of residual solidification in the pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rare earth electrolytic ingot preparation, and particularly to a rare earth metal electrolysis and casting system and method. BACKGROUND

[0002] The preparation of pure metal ingots of rare earth metals (such as praseodymium, neodymium, etc.) by electrolysis is a key link in the subsequent preparation of high-performance rare earth functional materials. Under the existing technology, the high-temperature molten metal liquid in the rare earth electrolysis furnace is generally discharged by suction casting, scooping, lifting, and other process methods, and then transferred to the ingot mold for cooling.

[0003] The scooping method is a traditional discharge method, which manually scoops out the rare earth metal liquid and pours it into the ingot mold for natural cooling. This method is low in efficiency, has certain risks, and the quality of the ingot is unstable. The lifting method is to use a crucible as a receiver and lift it out of the furnace as a whole, and then pour it into the ingot mold for natural cooling. However, the electrolysis reaction process is forced to stop during discharge, the process continuity is not strong, the electrolysis and discharge equipment structure is complex and large, and the operation also has certain risks.

[0004] Therefore, researchers have developed a suction casting method for ingot casting. This method uses suction force generated by negative pressure to extract the molten metal liquid into the ingot mold for cooling and forming. However, the present inventors found that the above-mentioned technology at least has the following technical problems in the process of implementing the technical scheme of the present application: Due to the particularity of the process of obtaining molten metal liquid by electrolysis, a part of the molten salt will enter the ingot mold with the metal liquid. Since the two are not mutually soluble and the metal liquid has high density, after cooling into a metal ingot, the molten salt will solidify on the surface of the metal (the presence of molten salt can prevent the high-temperature metal liquid from being oxidized). After removing the molten salt, the desired metal ingot can be obtained. However, the current suction casting usually uses a bent pipe to achieve this. One end of the bent pipe is inserted into the electrolytic molten metal liquid for suction, and the other end is horizontally arranged to spray the molten metal liquid into the ingot mold. Since this method transmits the suction pressure to the ingot mold through the metal liquid, the movement and fluctuation of the metal liquid in the ingot mold are more violent, resulting in rough edges of the formed ingot. At the same time, the mutual mixing of metal and molten salt due to dynamic solidification causes unevenness at the layering site, increasing the difficulty of removing the molten salt and inevitably leaving impurities in the metal. Therefore, some processes set the landing point of the sprayed metal liquid on the side of the ingot mold. Although this reduces the degree of mutual mixing of metal and molten salt, there are still large rough edges and problems of mutual mixing of metal and molten salt near the landing point of the metal liquid.

[0005] Meanwhile, because the molten metal needs to flow from the high-temperature electrolytic furnace through the suction bend into the low-temperature ingot mold, the flow distance is long. With the suction pressure difference and the flow characteristics of the molten metal both affected by temperature, it is difficult to control the ejection speed (ejection landing position) of the high-temperature molten metal. Strict control of the suction pressure difference and the temperature of the molten metal is required to accurately control the flow rate of the suction molten metal. The process window is narrow. Furthermore, the suction bend has a turning point, and the molten metal will solidify after cooling. Electrolysis to obtain molten metal takes a certain amount of time. Intermittent suction often results in molten metal residue at the turning point of the bend, which then solidifies, further increasing the difficulty of controlling the flow rate of the molten metal. The bend also needs to be cleaned frequently, but cleaning the solidified molten metal is difficult and affects continuous production. Summary of the Invention

[0006] This application provides a rare earth metal electrolytic suction casting system and method, which solves the problems of burrs and surface defects, narrow process window, and difficulty in cleaning suction pipes in existing suction casting processes. It achieves nonlinear pressure transmission, which enables static solidification of metal ingots, avoiding burrs and surface defects. By setting vertically without bends in the suction pipe, combined with a preheating scheme, the process window is wide and there is no residual solidified molten metal in the suction pipe, which greatly reduces the time and cost of equipment maintenance.

[0007] This application first provides a rare earth metal suction casting system, including:

[0008] The frame is fixedly mounted above the container holding the molten metal.

[0009] The overflow chamber is fixed on the frame, and the side wall is provided with an overflow port;

[0010] The suction tube is straight and vertical, with its lower end inserted into the molten metal and its upper end extending upward to communicate with the overflow chamber.

[0011] The mold chamber is connected to the overflow chamber and contains an ingot mold. The ingot mold is located below the overflow port and is used to receive the molten metal flowing out of the overflow port and cool it to form a metal ingot.

[0012] The negative pressure device is connected to the overflow chamber, suction pipe or mold chamber to generate negative pressure to draw the molten metal into the overflow chamber and to introduce the molten metal into the ingot mold by gravity overflow through the overflow port.

[0013] As some embodiments of this application, the inner wall of the suction tube is provided with a high-temperature resistant, non-stick coating to reduce molten metal residue.

[0014] As some embodiments of this application, the lower side of the overflow cavity is funnel-shaped to facilitate the return of molten metal.

[0015] As some embodiments of this application, the volume of the overflow chamber located below the overflow port is designed such that during the negative pressure suction process, the residence time of the molten metal in the overflow chamber is ≥3 seconds, so as to achieve sufficient pressure relief.

[0016] As some embodiments of this application, a V-shaped mounting base is provided at the bottom of the frame to fit and mount an overflow cavity with a funnel-shaped lower side.

[0017] As some embodiments of this application, the mold chamber is also provided with an openable and closable sealed door for sealing during ingot casting and for removing and replacing the ingot mold after casting.

[0018] As some embodiments of this application, a negative pressure regulating valve is also included, which is disposed at the output end of the negative pressure device to control the pumping rate, thereby controlling the height of the liquid ejected from the suction pipe, suppressing the overrush of the molten metal column, and reducing the impact force of the molten metal.

[0019] As some embodiments of this application, the frame is also provided with a sealing cover, so that the overflow chamber is in the sealed frame, which helps to reduce the temperature loss in the overflow chamber. At this time, the space between the frame and the overflow chamber is interconnected, and the negative pressure device can be directly connected to the sealed space in the frame.

[0020] As some embodiments of this application, the rack is not provided with a sealing cover.

[0021] As some embodiments of this application, a movable cover plate is provided above the overflow chamber to prevent the molten metal ejected from the suction pipe from splashing outside the overflow chamber.

[0022] As some embodiments of this application, the movable cover seals the overflow cavity.

[0023] As some embodiments of this application, it also includes an installation component for fixing the suction tube to the lower end of the frame and extending upward into the overflow chamber to communicate with the overflow chamber.

[0024] As some embodiments of this application, the outer wall of the suction tube is provided with an annular protrusion; this facilitates the installation, fixing, disassembly, and maintenance of the suction tube.

[0025] As some embodiments of this application, the mounting assembly includes a fixing member, a fastener, and a seal. The fixing member is fixedly disposed at the lower end of the mounting base, and its inner side surrounds the lower side of the overflow cavity. The fastener abuts the annular protrusion against the fixing member and is threadedly connected to the fixing member. The seal is disposed between the annular protrusion and the fixing member.

[0026] As some embodiments of this application, in order to increase sealing, the outer periphery of the annular protrusion and the fastener are also connected by a threaded connection.

[0027] As some embodiments of this application, the suction tube extends upwards into the overflow chamber by a height H, where H is 1mm to 5mm. This allows a small amount of molten metal to remain at the bottom of the overflow chamber after use, cooling and solidifying to form a solid metal seal, further improving the sealing performance of the system.

[0028] As some embodiments of this application, the outer periphery of the annular protrusion and the fastener may also be connected by a threaded connection.

[0029] As some embodiments of this application, it also includes a heat insulation component disposed on the wall or inside the overflow cavity to maintain the temperature of the molten metal in the overflow cavity above the metal melting point temperature and prevent the molten metal from solidifying prematurely.

[0030] As some embodiments of this application, the insulation component is also provided with a temperature sensor for real-time detection and feedback of the temperature of the molten metal in the overflow cavity, so as to adjust the power of the insulation component.

[0031] As some embodiments of this application, a protective gas device is also included to provide protective gas to the overflow cavity and the ingot mold to prevent the molten metal from being oxidized at high temperatures.

[0032] As some embodiments of this application, the overflow port is provided with a replaceable overflow nozzle to adapt to the suction casting of different metal ingots.

[0033] As some embodiments of this application, a liquid level sensor is provided in the overflow cavity to detect the liquid level height of the molten metal in the overflow cavity.

[0034] As some embodiments of this application, a control system is also provided, which is communicatively connected to a liquid level sensor, a negative pressure device, a negative pressure regulating valve, a protective gas device, and a heat insulation component, for automatically controlling the suction casting process.

[0035] As some embodiments of this application, the ingot mold is provided with a guide groove, the upper end of which is connected to the overflow port and the lower end extends to the bottom of the ingot mold, so as to reduce splashing and bubbles caused by the gravity overflow impact of molten metal.

[0036] As some embodiments of this application, a heating jacket is provided on the outer wall of the suction tube, and the temperature of the heating jacket is set to be 50°C to 100°C higher than the melting point of the molten metal, so as to prevent the molten metal from solidifying inside the suction tube.

[0037] This application also discloses a rare earth metal suction casting method, employing any of the rare earth metal suction casting systems described above, comprising the following steps:

[0038] Place the ingot mold into the mold chamber and seal the mold chamber;

[0039] The negative pressure device is started to suck the metal liquid in the metal liquid containing vessel into the overflow cavity through the vertical suction pipe, so that the liquid level of the metal liquid in the overflow cavity gradually rises;

[0040] When the liquid level of the metal liquid is higher than the overflow port, the metal liquid flows into the ingot mold from the overflow port under the action of gravity;

[0041] When the metal liquid sucked into the ingot mold reaches a set amount, the negative pressure device is stopped, so that the remaining metal liquid remains in the overflow cavity, and the metal liquid is directly sucked to start overflow when the next metal ingot is produced; or, when the metal liquid sucked into the ingot mold reaches a set amount, the negative pressure device is stopped and the pressure is released, so that the remaining metal liquid flows back to the metal liquid containing vessel under the action of gravity;

[0042] The metal liquid in the ingot mold is cooled and solidified to obtain a metal ingot.

[0043] As some embodiments of the present application, before starting the negative pressure device to suck the metal liquid into the overflow cavity, the following preheating step is performed:

[0044] The negative pressure device is started to suck the metal liquid in the metal liquid containing vessel into the overflow cavity, and when the liquid level of the metal liquid is close to the overflow port, the pressure is released after a period of time or directly released, so that the metal liquid flows back to the metal liquid containing vessel under the action of gravity, thereby preheating the overflow cavity and the suction pipe, and the preheating process is performed once or repeatedly 2-5 times.

[0045] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0046] 1. The quality of the ingot is significantly improved: the gravity overflow of the metal liquid into the ingot mold is realized through the overflow cavity structure, the negative pressure is avoided from directly acting on the metal liquid in the ingot mold, the nonlinear conduction of the pressure is realized, the metal liquid is cooled and solidified in a static environment, the ingot burr, bubbles and metal and molten salt hybridization phenomenon are effectively reduced, the surface of the metal ingot is flat, the internal structure is dense, and the subsequent molten salt stripping is facilitated.

[0047] 2. Wide process window and simple control: the vertical and straight suction pipe is used, the pressure release design of the overflow cavity is matched, the flow rate of the metal liquid is mainly controlled by the overflow port height and the negative pressure stability, the pressure value of the negative pressure does not need to be dynamically adjusted, the metal liquid temperature fluctuation is not sensitive, the process adaptability is strong, and the operation control is more simple and reliable.

[0048] 3. Low equipment maintenance cost: the suction pipe is vertically arranged and has no bending, the metal liquid can automatically flow back under the action of gravity after the negative pressure is stopped, the residual solidification is avoided, the pipeline blockage and cleaning frequency are greatly reduced, and the continuous operation ability of the equipment is improved.

[0049] 4. Strong adaptability, high degree of automation: through the optional sealing cover plate, movable cover plate, solid metal sealing and protective gas device structure design, effectively reduce heat loss and metal oxidation, can be applied to different metals, combined with heat preservation and heating sleeve, to ensure the temperature stability and composition purity of the metal liquid during transportation. The overflow nozzle can be replaced, combined with liquid level sensor, temperature sensor and control system, to realize automatic suction casting production of different metals and different specifications of ingot, and improve production efficiency and consistency. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical scheme in the specific embodiment of the present application or the prior art, the drawings needed to be used in the description of the specific embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0051] Figure 1 It is a structural schematic diagram of the embodiment of the present application.

[0052] Figure 2 It is Figure 1 A local enlarged schematic diagram at A in the figure.

[0053] In the drawings, 1 is a rack, 11 is a mounting seat, 12 is a sealing cover plate, 2 is an overflow cavity, 21 is an overflow port, 22 is a movable cover plate, 3 is a suction pipe, 31 is a ring convex part, 4 is a mold bin, 41 is an ingot mold, 42 is a sealing bin door, 5 is a negative pressure device, 51 is a negative pressure regulating valve, 6 is a mounting assembly, 61 is a fixing part, 62 is a fastener, 63 is a sealing part, 7 is a heat preservation part, 8 is a solid metal sealing, and 9 is a protective gas device. DETAILED DESCRIPTION

[0054] In order to better understand the above technical scheme, the above technical scheme will be described in detail in the specific embodiment.

[0055] Example 1: A rare earth metal suction casting system, as shown in Figure 1 It includes:

[0056] The rack 1 is fixedly arranged above the metal liquid containing container;

[0057] The overflow cavity 2 is fixedly arranged on the rack 1, and the side wall is provided with the overflow port 21;

[0058] The suction pipe 3 is vertically arranged without bending, and the lower end of the suction pipe 3 extends into the metal liquid, and the upper end extends upward and communicates with the overflow cavity 2;

[0059] The mold bin 4 is connected with the overflow cavity and is used for placing the ingot mold to receive the molten metal flowed out from the overflow port and to cool and form the metal ingot;

[0060] The mold bin 4 is connected with the overflow cavity 2 and internally places the ingot mold 41 which is arranged below the overflow port 21 and is used for receiving the molten metal flowed out from the overflow port 21 and cooling and forming the metal ingot;

[0061] The negative pressure device 5 is connected with the overflow cavity 2, the suction pipe 3 or the mold bin 4 and is used for generating the negative pressure to suck the molten metal into the overflow cavity 2 and to guide the molten metal into the ingot mold 41 through the overflow port 21 in the way of the gravity overflow.

[0062] The negative pressure adjusting valve 51 is further included and is arranged at the output end of the negative pressure device 5 and is used for controlling the air suction rate to control the liquid height sprayed out from the suction pipe 3, to suppress the overshoot of the molten metal liquid column and to reduce the metal liquid impact force.

[0063] Since the pressure generated by the negative pressure suction of the metal liquid is released in the overflow cavity 2, it is not transmitted into the ingot mold 41, and the metal liquid flows into the ingot mold 41 by gravity overflow, so that the metal liquid in the ingot mold 41 does not fluctuate violently to generate splashing burrs or bubbles, and after the metal liquid overflow is stopped, the metal liquid in the ingot mold 41 and the molten salt can be quickly separated without fluctuation, so that the cooling and solidification process is relatively static, the mutual mixing between the metal liquid and the molten salt is avoided, the quality of the metal ingot is greatly improved, and the subsequent stripping or grinding of the upper molten salt is facilitated. The metal liquid in the vertically arranged and unbent suction pipe 3 flows back to the metal liquid container under the action of gravity without negative pressure suction, so that the metal liquid is prevented from being solidified on the inner wall of the suction pipe 3. In this way, the flow rate of the metal liquid flowing into the ingot mold 41 depends on the negative pressure degree when the metal liquid height in the overflow cavity 2 reaches the overflow port 21, and since the negative pressure space size and the gas temperature in the overflow cavity 2 have been stabilized at this time, the size of the fixed negative pressure can be easily adjusted by the negative pressure adjusting valve 51 to control the flow rate of the metal liquid, so that the metal liquid flow is conveniently controlled. In this process, a relatively stable negative pressure size does not need to be provided by dynamic adjustment, the process setting is convenient, the control is simple, and at the same time, since the metal liquid in the ingot mold 41 basically has no fluctuation, the metal liquid amount can also be directly controlled by observing the metal liquid height in the ingot mold 41, and the metal liquid amount controlled by weight monitoring is also more stable. After the negative pressure disappears, the metal liquid in the overflow cavity 2 quickly flows back to the metal liquid container through the suction pipe 3, avoiding the adverse effects of temperature difference of the metal liquid in the subsequent suction casting process, so that the metal ingot obtained by suction casting has good quality consistency. Since the metal liquid enters the ingot mold 41 by gravity overflow, the flow characteristics of the metal liquid have little effect on the flow rate, and in addition, the vertically arranged suction pipe 3 has no bending and short path, so that the process window of the metal liquid temperature range is relatively wide, and only the solidification of the metal liquid after flowing into the ingot mold 41 needs to be ensured.

[0064] Embodiment 2: This embodiment is a rare earth metal suction casting system based on embodiment 1, and discloses a feasible specific scheme, as shown in Figure 1 、 Figure 2 ,

[0065] A high-temperature-resistant anti-sticking coating is arranged on the inner wall of the suction pipe 3 to reduce the residual metal liquid.

[0066] The lower side of the overflow cavity 2 is funnel-shaped, facilitating the backflow of the metal liquid.

[0067] The volume of the overflow cavity 2 below the overflow port 21 is designed to make the residence time of the metal liquid in the overflow cavity ≥3 seconds during the negative pressure suction, so as to achieve sufficient pressure relief.

[0068] The bottom of the frame 1 is provided with a V-shaped mounting seat 11 to fit the funnel-shaped overflow cavity 2.

[0069] In this embodiment, the frame 1 is also provided with a sealing cover plate 12, so that the overflow cavity 2 is in a sealed frame 1, which is beneficial to reduce the loss of temperature in the overflow cavity 2. At this time, the space inside the frame 1, the overflow cavity 2 and the mold bin 4 are in communication with each other, and the negative pressure device 5 can be directly communicated with the sealed space in the mold bin 4.

[0070] The mold bin 4 is also provided with an openable and closable sealing bin door 42 for sealing during ingot casting and removing and replacing the ingot mold 41 after ingot casting.

[0071] An active cover plate 22 is provided above the overflow cavity 2 to prevent the metal liquid sprayed from the suction pipe 3 from splashing outside the overflow cavity 2. The active cover plate 22 can also be used to seal the overflow cavity 2 or a hole is provided on the active cover plate 22 to make the overflow cavity 2 and the inside of the frame 1 and the mold bin 4 quickly balance the pressure.

[0072] Of course, in other embodiments of the present application, the frame 1 can also not be provided with a seal, and the overflow cavity 2 is directly sealed to make the overflow cavity 2 and the mold bin 4 communicate with each other.

[0073] Embodiment 3: This embodiment is also a rare earth metal suction casting system based on embodiment 1, and discloses another feasible specific scheme, as shown in Figure 1 、 Figure 2

[0074] It also includes a mounting assembly 6, which is used to fixedly install the suction pipe 3 at the lower end of the frame 1 and extend upward into the overflow cavity 2 to communicate with the overflow cavity 2.

[0075] The outer side wall of the suction pipe 3 is provided with a ring protrusion 31; which is convenient for installation, fixation, disassembly and maintenance of the suction pipe 3;

[0076] The mounting assembly 6 includes a fixing piece 61, a fastener 62 and a sealing piece 63. The fixing piece 61 is fixedly arranged at the lower end of the mounting seat 11, and the inner side thereof embraces the lower side of the overflow cavity 2. The fastener 62 abuts against the fixing piece 61 and is threadedly connected with the fixing piece 61. The sealing piece 63 is arranged between the ring protrusion 31 and the fixing piece 61. In order to increase the sealing performance, the outer periphery of the ring protrusion 31 and the fastener 62 can also be threadedly connected.

[0077] In this embodiment, the suction pipe 3 extends upward in the overflow cavity 2 by a height H, and H is 1mm-5mm, so that a small amount of metal liquid will be left in the bottom of the overflow cavity 2 after the system is used to form a solid metal seal 8, which further improves the sealing performance of the system.

[0078] ​The heat preservation member 7 is arranged on the wall or inside of the overflow cavity 2, and is used to maintain the temperature of the metal liquid in the overflow cavity 2 above the melting point of the metal, so as to avoid the metal liquid from solidifying too early.

[0079] In the embodiment, the heat preservation member 7 is arranged outside and below the overflow cavity 2.

[0080] The protective gas device 9 is further arranged, and is used to provide protective gas for the overflow cavity 2 and the ingot mold 41, so as to avoid the metal liquid from being oxidized in the high-temperature state.

[0081] According to common sense, the temperature of the metal in the liquid state is generally high, so the various components involved in the present application need to be made of corresponding high-temperature-resistant materials.

[0082] In order to further adapt to the needs of actual production, the replaceable overflow nozzle is arranged at the overflow port 21 to adapt to the suction casting of different metal ingots, that is, different sizes and cross-sectional shapes of the overflow nozzle can be selected according to the metal ingot to be made.

[0083] The liquid level sensor can be further arranged in the overflow cavity 2, and is used to detect the liquid level height of the metal liquid in the overflow cavity 2.

[0084] The control system can be further arranged, and is in communication connection with the liquid level sensor, the negative pressure device 5, the negative pressure adjusting valve 51, the protective gas device 9 and the heat preservation member 7, and is used to automatically control the whole suction casting process.

[0085] The flow guide groove can be further arranged on the ingot mold 41, the upper end of the flow guide groove is in butt joint with the overflow port 21, and the lower end extends to the bottom of the ingot mold 41, so as to reduce the splashing and bubbles caused by the gravity overflow impact of the metal liquid.

[0086] The heating sleeve can be further arranged on the outer wall of the suction pipe 3, the temperature of the heating sleeve is set to be 50-100℃ higher than the melting point of the metal liquid, so as to prevent the metal liquid from solidifying in the suction pipe 3.

[0087] Embodiment 4: The rare earth metal suction casting system in embodiment 2 is used for the metal ingot making of the electrolytic system molten metal liquid of the metal praseodymium, and one of the methods comprises the following steps:

[0088] The ingot mold 41 is placed into the mold bin 4, and the sealing bin door 42 is closed to seal the mold bin 4;

[0089] The negative pressure device 5 is started, and the molten rare earth metal liquid in the electrolytic cell is sucked into the overflow cavity 2 through the vertical suction pipe 3, so that the liquid level of the metal liquid in the overflow cavity 2 gradually rises, and when the liquid level of the metal liquid is higher than the overflow port 21, the metal liquid overflows into the ingot mold 41 under the action of gravity;

[0090] When the metal liquid sucked into the ingot mold 41 reaches a set amount, the negative pressure device 5 is stopped, and the remaining metal liquid is left in the overflow cavity 2, and the metal liquid is directly sucked to start overflowing when the next metal ingot is produced;

[0091] After the metal liquid in the ingot mold 41 reaches a specified amount, it is cooled and solidified to obtain a metal praseodymium ingot.

[0092] Embodiment 5: This embodiment is one of the methods for producing metal ingots of molten metal liquid in a neodymium electrolytic system using the rare earth metal suction casting system of embodiment 2, which includes the following steps:

[0093] The ingot mold 41 is placed into the mold bin 4, and the sealing bin door 42 is closed to seal the mold bin 4;

[0094] The negative pressure device 5 is started, and the molten rare earth metal liquid in the electrolytic cell is sucked into the overflow cavity 2 through the vertical suction pipe 3, and when the liquid level of the metal liquid is close to the overflow port 21, the pressure is released after a period of time or directly released, so that the metal liquid flows back to the electrolytic cell under the action of gravity, and the overflow cavity 2 and the suction pipe 3 are preheated, which can be repeated multiple times to achieve sufficient preheating.

[0095] After preheating is completed, the negative pressure device 5 is started again, and the molten rare earth metal liquid in the electrolytic cell is sucked into the overflow cavity 2 through the vertical suction pipe 3, so that the liquid level of the metal liquid in the overflow cavity 2 gradually rises, and when the liquid level of the metal liquid is higher than the overflow port 21, the metal liquid overflows into the ingot mold 41 under the action of gravity;

[0096] When the metal liquid sucked into the ingot mold 41 reaches a set amount, the negative pressure device 5 is stopped and the pressure is released, so that the remaining metal liquid flows back to the electrolytic cell through the suction pipe 3 under the action of gravity;

[0097] After the metal liquid in the ingot mold 41 reaches a specified amount, it is cooled and solidified to obtain a metal neodymium ingot;

[0098] The sealing bin door 42 is opened, and the ingot mold 41 in the mold bin 4 is taken out for demolding, and a new empty ingot mold 41 is placed, and the sealing bin door 42 is closed to seal the mold bin 4.

[0099] Of course, after the ingot mold 41 is taken out, the ingot mold 41 can be vibrated for demolding by a vibration device to reduce the adhesion of the ingot surface.

[0100] In other embodiments of the present application, the use of the system and method of the present application is not limited to the praseodymium and neodymium metals mentioned in the embodiments, but can also be used for other single element metals or alloys that can be prepared by suction casting into ingots.

[0101] While the preferred embodiments of the application have been described, additional variations and modifications can be made to the embodiments by those skilled in the art once they learn of the basic inventive concepts. Therefore, the appended claims are intended to encompass within their scope all such variations and modifications as are included within the scope of the application.

[0102] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A rare earth metal suction casting system, characterized in that, include: The frame (1) is fixedly installed above the container holding the molten metal; An overflow chamber (2) is fixedly mounted on the frame (1), and an overflow port (21) is provided on the side wall; The suction tube (3) is straight and vertical. The lower end of the suction tube (3) extends into the molten metal, and the upper end extends upward to communicate with the overflow chamber (2). The mold chamber (4) is connected to the overflow chamber (2) and contains an ingot mold (41). The ingot mold (41) is located below the overflow port (21) and is used to receive the molten metal flowing out of the overflow port (21) and cool it to form a metal ingot. The negative pressure device (5) is connected to the overflow chamber (2), the suction pipe (3) or the mold chamber (4) to generate negative pressure to draw the molten metal into the overflow chamber (2) and to introduce the molten metal into the ingot mold (41) by gravity overflow through the overflow port (21).

2. The rare earth metal suction casting system according to claim 1, characterized in that, The inner wall of the suction tube (3) is provided with a high-temperature resistant and non-stick coating; The lower side of the overflow cavity (2) is funnel-shaped; The volume of the overflow chamber (2) located below the overflow port (21) is designed such that the residence time of the molten metal in the overflow chamber is ≥3 seconds during the negative pressure suction process, so as to achieve sufficient pressure relief; The bottom of the frame (1) is provided with a V-shaped mounting base (11) to fit the overflow cavity (2) which is funnel-shaped on the lower side; It also includes a negative pressure regulating valve (51), which is set at the output end of the negative pressure device (5) to control the pumping rate, thereby controlling the height of the liquid ejected from the suction pipe (3), suppressing the overrush of the molten metal liquid column, and reducing the impact force of the molten metal liquid.

3. The rare earth metal suction casting system according to claim 1, characterized in that, The frame (1) is also provided with a sealing cover (12), so that the overflow chamber (2) is in the sealed frame (1), which helps to reduce the temperature loss in the overflow chamber (2); A movable cover plate (22) is provided above the overflow chamber (2) to prevent the molten metal sprayed from the suction pipe (3) from splashing outside the overflow chamber (2); The mold compartment (4) is also equipped with an openable and closable sealed compartment door (42) for sealing during ingot casting and removing and replacing the ingot mold (41) after casting.

4. The rare earth metal suction casting system according to claim 1, characterized in that, It also includes an installation component (6), which is used to fix the suction tube (3) to the lower end of the frame (1) and extend upward into the overflow chamber (2) to communicate with the overflow chamber (2).

5. A rare earth metal suction casting system according to claim 4, characterized in that, The outer wall of the suction tube (3) is provided with an annular protrusion (31); this facilitates the installation, fixing, disassembly, and maintenance of the suction tube (3). The mounting assembly (6) includes a fixing member (61), a fastener (62) and a seal (63). The fixing member (61) is fixedly disposed at the lower end of the mounting base (11), and its inner side surrounds the lower side of the overflow cavity (2). The fastener (62) pushes the annular protrusion (31) against the fixing member (61) and is threadedly connected to the fixing member (61). The seal (63) is disposed between the annular protrusion (31) and the fixing member (61).

6. The rare earth metal suction casting system according to claim 5, characterized in that, The suction tube (3) extends upward to a height H in the overflow chamber (2), where H is 1mm to 5mm. This ensures that after the system is used, a small amount of molten metal will remain at the bottom of the overflow chamber (2) and solidify to form a solid metal seal (8). The outer periphery of the annular protrusion (31) and the fastener (62) are connected by a thread.

7. A rare earth metal suction casting system according to claim 1, characterized in that, It also includes a heat insulation component (7), which is set in the wall or inside of the overflow cavity (2) to maintain the temperature of the molten metal in the overflow cavity (2) above the melting point temperature of the metal and prevent the molten metal from solidifying too early. A temperature sensor is also provided on the insulation component (7) to detect the temperature of the molten metal in the overflow cavity (2) in real time and provide feedback so as to adjust the power of the insulation component (7); It also includes a protective gas device (9) for providing protective gas to the overflow chamber (2) and the ingot mold (41) to prevent the molten metal from being oxidized at high temperatures.

8. A rare earth metal suction casting system according to claim 7, characterized in that, The overflow port (21) is equipped with a replaceable overflow nozzle to adapt to the suction casting of different metal ingots; A liquid level sensor is installed in the overflow chamber (2) to detect the liquid level height of the molten metal in the overflow chamber (2); It is also equipped with a control system that is connected in communication with the liquid level sensor, negative pressure device (5), negative pressure regulating valve (51), protective gas device (9) and insulation component (7); The ingot mold (41) is provided with a guide groove, the upper end of which is connected to the overflow port (21), and the lower end extends to the bottom of the ingot mold (41); A heating jacket is provided on the outer wall of the suction tube (3). The temperature of the heating jacket is set to be 50°C to 100°C higher than the melting point of the molten metal to prevent the molten metal from solidifying inside the suction tube (3).

9. A method for suction casting rare earth metals, characterized in that, The rare earth metal suction casting system as described in any one of claims 1 to 8 includes the following steps: Place the ingot mold (41) into the mold chamber (4) and seal the mold chamber (4); Start the negative pressure device (5) and suck the molten metal in the container into the overflow chamber (2) through the vertical suction pipe (3), so that the liquid level of the molten metal in the overflow chamber (2) gradually rises. When the liquid level of the molten metal is higher than the overflow port (21), the molten metal overflows from the overflow port (21) into the ingot mold (41) under the action of gravity; When the molten metal drawn into the ingot mold (41) reaches the set amount, the negative pressure device (5) is stopped, so that the remaining molten metal remains in the overflow chamber (2) and the molten metal is directly drawn to start overflowing when the next metal ingot is produced; or, when the molten metal drawn into the ingot mold (41) reaches the set amount, the negative pressure device (5) is stopped and the pressure is released, so that the remaining molten metal flows back to the molten metal container through the suction pipe (3) under the action of gravity; The metal ingot is obtained by allowing the molten metal in the ingot mold (41) to stand still, cool, and solidify.

10. A rare earth metal suction casting method according to claim 9, characterized in that, Before starting the negative pressure device (5) to draw the molten metal into the overflow chamber (2), the following preheating steps are performed: Start the negative pressure device (5) and suck the molten metal in the container into the overflow chamber (2) through the vertical suction pipe (3). When the liquid level of the molten metal is close to the overflow port (21), maintain it for a period of time and then release the pressure or release the pressure directly so that the molten metal flows back into the container under the action of gravity. In this way, the overflow chamber (2) and the suction pipe (3) are preheated. The preheating process is performed once or repeated 2 to 5 times.

Images