Sodium purification equipment and process for sodium reduction of tantalum powder

Abstract

A sodium purification device for sodium reduction of tantalum powder and its process, relating to the field of metal smelting; comprising a heating furnace, a purification tank, an oil removal device, an air pressure device and a refined sodium storage tank; the purification tank is placed in the heating furnace, and the purification tank is respectively connected to the oil removal device, the air pressure device and the refined sodium storage tank; the purification tank comprises a tank body, a sealing cover, a sodium ingot placement barrel, a primary filtering structure, a secondary filtering tube and a tertiary filtering tube, the top of the tank body is detachably connected to the sealing cover, the sealing cover is provided with a sodium ingot feeding port, the tank body is provided with a sodium ingot placement barrel, and the sodium ingot feeding port corresponds to the position of the sodium ingot placement barrel. The sodium purification device of the present invention is an integrated device for the oil removal process and the sodium oxide removal process, which can remove oil in the purification tank and effectively intercept sodium slag through multiple filtering structures, has simple equipment, short process flow, easy disassembly and cleaning, low safety hazards, and has the characteristics of good purification effect and high efficiency.

Description

Technical Field

[0001] The invention belongs to the field of metal smelting, and in particular relates to sodium purification equipment and a process for sodium reduction of tantalum powder. Background Art

[0002] Sodium reduction of tantalum powder is the most basic process for producing tantalum metal and the main method for producing capacitor-grade tantalum powder. Sodium metal is obtained by electrolyzing molten sodium chloride to obtain liquid sodium metal, and then quickly extruding sodium metal ingots in a semi-solidified state into a double-layer polyethylene bag placed in a tin packaging barrel, excluding air, and then tying the bag mouth and finally sealing it in a tin barrel. This is also stipulated in the Industrial Sodium Metal Standard (GB / T22379-2017).

[0003] In the process of extruding sodium ingots and packaging, the air cannot be isolated, and the sodium is not completely cooled, so it is easy to form a sodium oxide shell on the surface of the sodium ingot. The longer it is exposed to the air and the higher the temperature, the thicker the sodium oxide shell. In the process of extruding sodium ingots, in order to reduce the oxidation of sodium, a layer of paraffin oil needs to be coated on the surface of the sodium ingot.

[0004] Therefore, the paraffin oil, coating and sodium oxide shell on the surface of the finished sodium metal produced according to the national standard are unavoidable; some manufacturers of sodium-reduced tantalum powder, such as Ningxia Dongfang Tantalum Industry, which is very close to the sodium metal factory, use stainless steel tanks to load liquid sodium from the sodium metal manufacturer for purification. Since it is a non-national standard flammable and explosive packaging and transportation, the manufacturer must solve the transportation problem by himself, and it must be a professional dangerous goods transport vehicle, must have a certain amount of transportation, must be a special tank, and must apply for filing; due to the long distance and large canning volume, the sodium metal manufacturer may not be able to complete all canning in a short time, and must be transported after the sodium metal is completely cooled. Therefore, the transportation cost of sodium metal is high, the transportation time is long, and the user bears more risks. After placing an order for the national standard barreled sodium ingots, the sodium metal manufacturer can entrust a special logistics to transport them to designated locations across the country.

[0005] In the process of sodium reduction tantalum powder production, paraffin oil will increase the carbon content of tantalum powder; sodium oxide will not only block the sodium delivery pipeline and valves, but also does not participate in the reaction process. After it comes out of the furnace, the sodium hydroxide solution formed will corrode the surface of tantalum powder, thereby increasing the oxygen content of tantalum powder; therefore, degreasing and sodium oxide must be removed.

[0006] The traditional process of metal sodium purification is melting sodium-degreasing-coarse filtration-ceramic filtration-cold trap-fine sodium. Each process node corresponds to a heatable tank, and the tanks are connected to the valves through pipes with external heating and insulation materials. It is very similar to the Chinese patent CN1238541C, except that the decalcification step is reduced. The entire process is long, with many tanks, long pipes, valves, and interfaces. These valves and interfaces need to be insulated. Once the temperature at a certain point is low, the sodium cannot be transported; in order to facilitate installation and cleaning, valves, pipes and other interfaces must have temperature-resistant high-temperature sealing pads, which are prone to leakage points. Once leaking, it is easy to burn and there are many safety hazards; after a period of use, fine sodium slag will block the filter, and disassembling and cleaning the sodium slag of the filter part is the lowest cost and most efficient way to solve the sodium slag blockage. In this way, it is necessary to disassemble multiple pipes and filters to clean, wash, dry, and then install them back, which increases the manual workload, and it is also necessary to install each seal, each section of heating and insulation, and each temperature control thermocouple in place, otherwise the sodium purification system cannot work properly.

[0007] Chinese patent CN206015048U has improved the equipment and process of sodium purification to make it suitable for sodium reduction production of tantalum powder, but the equipment is still not compact enough (the oil storage tank and the purification tank are two tanks). Although it is easy to disassemble, it still leaves safety hazards (the transportation of metallic sodium is heated and pressurized, and the quick-release flange seal is generally rubber, such as high-temperature resistant fluororubber, which has the risk of leakage under heated and pressurized conditions).

[0008] The method of purifying metallic sodium by a cold trap disclosed in Chinese Patent 201520545492.2 is effective for purifying liquid metallic sodium, but cannot be used for purifying metallic sodium ingots. Large pieces of oxide scale on the surface of the metallic sodium ingots quickly clog the metal wires therein, and the cold trap has strict requirements for temperature control, otherwise it will not play a filtering role. Summary of the invention

[0009] In order to overcome the shortcomings of the prior art, one of the objects of the present invention is to provide a sodium purification device for sodium-reduced tantalum powder. The device has a compact structure, a short process, is easy to disassemble and clean, has low safety hazards, has the characteristics of good purification effect and high efficiency, and effectively solves the problem of sodium slag blockage.

[0010] The second object of the present invention is to provide a sodium purification process for sodium-reduced tantalum powder, which can effectively remove oil and sodium oxide, has a short process flow, good purification effect and high efficiency.

[0011] The purpose of the present invention is achieved by the following technical solutions:

[0012] A sodium purification device for sodium reduction of tantalum powder, comprising a heating furnace, a purification tank, an oil removal device, an air pressure device and a refined sodium storage tank; the purification tank is placed in the heating furnace, and the purification tank is respectively connected to the oil removal device, the air pressure device and the refined sodium storage tank;

[0013] The purification tank comprises a tank body, a sealing cover, a sodium ingot placement barrel, a primary filtering structure, a secondary filtering tube and a tertiary filtering tube. The top of the tank body is detachably connected to the sealing cover. The sealing cover is provided with a sodium ingot feeding port. The tank body is provided with a sodium ingot placement barrel. The sodium ingot feeding port corresponds to the position of the sodium ingot placement barrel. The sodium ingot placement barrel is an annular structure composed of an outer wall, an inner wall and a barrel bottom connecting the outer wall and the inner wall. The outer wall is provided with densely distributed small holes. A primary filtering structure is provided on the side of the outer wall close to the tank body. A secondary filtering tube is provided on the side of the inner wall away from the tank body. The secondary filtering tube is detachably connected to the sealing cover. A tertiary filtering tube is provided inside the secondary filtering tube. The tertiary filtering tube is connected to a refined sodium storage tank.

[0014] Furthermore, the primary filtering structure is a screen, and the aperture of the screen is 80 to 150 meshes.

[0015] Furthermore, the secondary filter tube includes a first steel tube located at the top, a first porous tube located at the bottom, and a first bottom plate, the first porous tube is detachably connected to the first steel tube and the first bottom plate, respectively, the first porous tube is lower than the sodium ingot placement barrel, and the pore size of the first porous tube is 3 to 15 μm.

[0016] Furthermore, the three-stage filter tube includes a second steel tube located at the upper part, a second porous tube located at the lower part, and a second bottom plate, and the second porous tube is detachably connected to the second steel tube and the second bottom plate, respectively.

[0017] Furthermore, the length of the second porous tube is 1 / 2 to 3 / 4 of the total length of the three-stage filter tube, and the pore size of the second porous tube is 0.2 to 2 μm.

[0018] Furthermore, the heating furnace includes a furnace body, a resistance heating wire and a temperature-controlling thermocouple. The inner wall of the furnace body is filled with a heat-insulating material. A resistance heating wire is arranged inside the heat-insulating material. The temperature-controlling thermocouple extends into the interior of the purification tank.

[0019] Furthermore, the oil removal device includes an oil removal pipe, a buffer tank and a vacuum pump, one end of the oil removal pipe is connected to the sealing cover, the other end of the oil removal pipe is connected to the buffer tank, and the vacuum pump is connected to the buffer tank.

[0020] Furthermore, the refined sodium storage tank is connected with the sodium delivery pipe and the argon device, and an upper liquid level and a lower liquid level are arranged inside the refined sodium storage tank, and the lower liquid level is higher than the bottom of the sodium outlet pipe.

[0021] A sodium purification process for sodium-reduced tantalum powder comprises the following steps:

[0022] S1, melting and degreasing; placing the sodium ingot into the sodium ingot placing bucket in the sodium purification tank, starting the vacuum pump and opening the vacuum valve, making the vacuum degree of the degreasing device 0.01-0.09MPa, the temperature between 20-260°C, starting the heating furnace to heat the sodium purification tank, and after the temperature reaches 250-270°C, keeping the temperature for 0.5-4h, obtaining liquid metallic sodium, closing the vacuum valve and stopping the vacuum pump;

[0023] S2, purification; start the air pressure device to add argon gas, keep the pressure of the sodium purification tank at 0.03-0.05MPa, and the temperature at 140℃-150℃. Under the argon pressure, liquid metallic sodium flows out from the small holes on the outer wall of the sodium ingot placement barrel, and passes through the primary filtering structure for coarse filtration. The liquid metallic sodium after coarse filtration passes through the secondary filtering tube and the tertiary filtering tube at the center of the sodium ingot placement barrel for fine filtration to obtain refined sodium liquid. The sodium slag is retained in the sodium purification tank, and the refined sodium liquid is transported from the top of the tertiary filtering tube to the sodium delivery pipe, and the sodium delivery pipe is kept at a temperature of 100℃-125℃;

[0024] S3, collect refined sodium; detect and control the pressure of the refined sodium storage tank to 0.025~0.03MPa, and the liquid level has not reached the upper liquid level, and open the sodium delivery valve, the refined sodium liquid flows into the refined sodium storage tank through the sodium delivery pipeline, and when it is detected that the liquid level of the refined sodium storage tank reaches the upper liquid level, or there is no liquid metallic sodium in the sodium purification tank, close the sodium delivery valve.

[0025] Furthermore, it also includes a slag removal step, which specifically includes opening the sealing cover, hanging out the old sodium ingot placement barrel, replacing the new sodium ingot placement barrel, closing the sealing cover, cleaning the old sodium ingot placement barrel, and drying it for standby use; when the secondary filter tube and / or the tertiary filter tube need to be cleaned, the first porous tube and / or the second porous tube are removed and replaced, and the old first porous tube and / or the second porous tube are cleaned and dried for standby use.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The sodium purification equipment of the present invention is an integrated equipment for oil removal process and sodium oxide removal process, can remove oil in the purification tank and effectively intercept sodium slag through multiple filtering structures, has simple equipment, short process flow, easy disassembly and cleaning, low safety hazard, and has the characteristics of good purification effect and high efficiency.

[0028] The sodium purification process of the present invention can effectively remove oil and sodium oxide, has a short process flow, good purification effect, high efficiency, energy saving and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1The present invention is a schematic structural diagram of a sodium purification device for sodium-reduced tantalum powder.

[0030] Figure 2 The present invention Figure 1 Schematic diagram of the structure of the middle tertiary filter tube.

[0031] Figure 3 The invention relates to an automatic control display system.

[0032] Among them, 100, heating furnace; 101, resistance heating wire; 102, insulation material; 200, purification tank; 201, supporting rib plate; 300, sodium ingot placement barrel; 3001, primary filtering structure; 301, inner wall; 302, sealing ring; 400, sealing cover; 401, temperature control thermocouple; 402, sodium ingot feeding port; 403, secondary filtering tube; 4031, first porous tube; 4032, first bottom plate; 404, liquid level meter; 405, air pressure device; 4051, argon pressure gauge; 4052, argon outlet valve; 4053, argon inlet valve; 500 , three-stage filter tube; 501, second steel pipe; 5011, second porous tube; 5012, second bottom plate; 502, valve external insulation material; 503, sodium delivery valve; 600, buffer tank; 601, oil removal pipe; 602, vacuum valve; 603, negative pressure gauge; 604, vacuum pump; 700, refined sodium storage tank; 701, heating and insulation body; 702, sodium outlet pipe; 703, temperature control thermocouple; 704, lower liquid level; 705, upper liquid level; 706, discharge valve; 707, argon device; 708, sodium delivery outlet valve; 709, sodium delivery pipe; 710, heating and insulation layer. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0034] like Figure 1-2 As shown, a sodium purification device for sodium reduction of tantalum powder includes a heating furnace 100, a purification tank 200, an oil removal device, an air pressure device 405 and a refined sodium storage tank 700; the purification tank 200 is placed in the heating furnace 100, and the purification tank 200 is connected to the oil removal device, the air pressure device 405 and the refined sodium storage tank 700 respectively;

[0035] The purification tank 200 includes a tank body, a sealing cover 400, a sodium ingot placement barrel 300, a primary filtering structure 3001, a secondary filtering tube 403 and a tertiary filtering tube 500. The top of the tank body is detachably connected to the sealing cover 400. The sealing cover 400 is provided with a sodium ingot feeding port 402. The tank body is provided with a sodium ingot placement barrel 300. The sodium ingot feeding port 402 corresponds to the position of the sodium ingot placement barrel 300. The sodium ingot placement barrel 300 is an annular structure composed of an outer wall, an inner wall 301 and a barrel bottom connecting the outer wall and the inner wall 301. The outer wall is provided with densely distributed small holes. The primary filtering structure 3001 is provided on the side of the outer wall close to the tank body. The side of the inner wall 301 away from the tank body is provided with a secondary filtering tube 403. The secondary filtering tube 403 is detachably connected to the sealing cover 400. A tertiary filtering tube 500 is provided inside the secondary filtering tube 403. The tertiary filtering tube 500 is connected to the refined sodium storage tank 700.

[0036] This equipment integrates oil removal process and sodium oxide removal process. It can remove oil in the purification tank 200 and effectively intercept sodium slag through multiple filtering structures. The equipment is simple, the process flow is short, the disassembly and cleaning are easy, the safety hazard is low, and it has the characteristics of good purification effect and high efficiency.

[0037] Furthermore, the primary filtering structure 3001 is a screen, and the aperture of the screen is 80 to 150 meshes, preferably 100 to 120 meshes, which can roughly filter the sodium slag.

[0038] Furthermore, the secondary filter tube 403 includes a first steel tube located at the top, a first porous tube 4031 located at the bottom, and a first bottom plate 4032. The first porous tube 4031 is detachably connected to the first steel tube and the first bottom plate 4032, respectively. The first porous tube 4031 is lower than the sodium ingot placement barrel 300. Its purpose is to purify the melted crude sodium as much as possible. The pore size of the first porous tube 4031 is 3 to 15 μm, preferably 3 to 10 μm, and more preferably 3 to 5 μm, achieving a good balance between purification effect and purification efficiency.

[0039] like Figure 2 As shown, the three-stage filter tube 500 includes a second steel tube 501 at the top, a second porous tube 5011 at the bottom, and a second bottom plate 5012, wherein the second porous tube 5011 is detachably connected to the second steel tube 501 and the second bottom plate 5012. Preferably, the second porous tube 5011 is threadedly connected to the second steel tube 501 and the second bottom plate 5012.

[0040] Furthermore, the length of the second porous tube 5011 is 1 / 2 to 3 / 4 of the total length of the three-stage filter tube 500, and the pore size of the second porous tube 5011 is 0.2 to 2 μm, preferably 0.5 to 1.5 μm.

[0041] Furthermore, the heating furnace 100 includes a furnace body, a resistance heating wire 101 and a temperature-controlling thermocouple 401 . The inner wall 301 of the furnace body is filled with a heat-insulating material 102 . The inner side of the heat-insulating material 102 is provided with a resistance heating wire 101 . The temperature-controlling thermocouple 401 extends into the purification tank 200 .

[0042] Furthermore, the oil removal device includes an oil removal pipe 601, a buffer tank 600 and a vacuum pump 604, one end of the oil removal pipe 601 is connected to the sealing cover 400, the other end of the oil removal pipe 601 is connected to the buffer tank 600, and the vacuum pump 604 is connected to the buffer tank 600.

[0043] Furthermore, the refined sodium storage tank 700 is connected to the sodium delivery pipe 709 and the argon device 707, and an upper liquid level 705 and a lower liquid level 704 are provided inside the refined sodium storage tank 700, and the lower liquid level 704 is higher than the bottom of the sodium outlet pipe 702. The gas pressure can be controlled by the argon device 707, and the upper liquid level 705 and the lower liquid level 704 are used to monitor the liquid level of the refined sodium storage tank 700 to prevent the liquid level from exceeding a critical value.

[0044] A sodium purification process for sodium-reduced tantalum powder comprises the following steps:

[0045] S1, melting and degreasing; placing the sodium ingot into the sodium ingot placing barrel 300 in the sodium purification tank 200, starting the vacuum pump 604 and opening the vacuum valve 602, making the vacuum degree of the degreasing device 0.01-0.09MPa, the temperature between 20-260°C, starting the heating furnace 100 to heat the sodium purification tank 200, after the temperature reaches 250-270°C, keeping the temperature for 0.5-4h, obtaining liquid metallic sodium, closing the vacuum valve 602 and stopping the vacuum pump 604;

[0046] S2, purification; start the air pressure device 405 to add argon gas, keep the pressure of the sodium purification tank 200 at 0.03-0.05MPa, and the temperature at 140°C-150°C. Under the argon pressure, the liquid metallic sodium flows out from the small holes on the outer wall of the sodium ingot placement barrel 300, and passes through the primary filtering structure 3001 for coarse filtration. The liquid metallic sodium after coarse filtration is respectively finely filtered through the secondary filter tube 403 and the tertiary filter tube 500 at the center of the sodium ingot placement barrel 300 to obtain refined sodium liquid. The sodium slag is trapped in the sodium purification tank 200. The refined sodium liquid is transported from the top of the tertiary filter tube 500 to the sodium delivery pipe 709, and the sodium delivery pipe 709 maintains a temperature of 100°C-125°C;

[0047] S3, collect refined sodium; detect and control the pressure of the refined sodium storage tank to 0.025~0.03MPa, and the liquid level has not reached the upper liquid level 705, and open the sodium delivery valve 503, the refined sodium liquid flows into the refined sodium storage tank through the sodium delivery pipe 709, and when it is detected that the liquid level of the refined sodium storage tank 700 reaches the upper liquid level 705, or there is no liquid metallic sodium in the sodium purification tank 200, close the sodium delivery valve 503.

[0048] Furthermore, it also includes a slag removal step, which specifically includes opening the sealing cover 400, hanging out the old sodium ingot placement barrel 300, replacing the new sodium ingot placement barrel 300, closing the sealing cover 400, cleaning and drying the old sodium ingot placement barrel 300 for later use; when the secondary filter tube 403 and / or the tertiary filter tube 500 need to be cleaned, the first porous tube 4031 and / or the second porous tube 5011 are removed and replaced, and the old first porous tube 4031 and / or the second porous tube 5011 are cleaned and dried for later use.

[0049] The sodium purification process of the present invention can effectively remove oil and sodium oxide, has a short process flow, good purification effect, high efficiency, energy saving and environmental protection.

[0050] Embodiment 1,

[0051] like Figure 1-2 As shown, a sodium purification device for sodium reduction of tantalum powder includes a heating furnace 100, a purification tank 200, an oil removal device, an air pressure device 405 and a refined sodium storage tank 700; the purification tank 200 is placed in the heating furnace 100, and the purification tank 200 is connected to the oil removal device, the air pressure device 405 and the refined sodium storage tank 700 respectively;

[0052] The heating furnace 100 includes a furnace body, a resistance heating wire 101 and a temperature-controlling thermocouple 401 . The inner wall 301 of the furnace body is filled with a heat-insulating material 102 . The inner side of the heat-insulating material 102 is provided with a resistance heating wire 101 . The temperature-controlling thermocouple 401 extends into the interior of the purification tank 200 .

[0053] The purification tank 200 includes a tank body, a sealing cover 400, a sodium ingot placement barrel 300, a primary filtering structure 3001, a secondary filtering tube 403 and a tertiary filtering tube 500. The top of the tank body is detachably connected to the sealing cover 400. The sealing cover 400 is provided with a sodium ingot feeding port 402, a detachable temperature-controlling thermocouple 401, a liquid level gauge 404, an oil removal pipe 601, an air pressure device 405 and a secondary filtering tube 403. A sealing ring 302 is provided between the sealing ring 302 and the tank body. A supporting rib plate 201 is provided at the bottom of the tank body for placing the sodium ingot placement barrel 300. The sodium ingot feeding port 402 corresponds to the position of the sodium ingot placement barrel 300. The sodium ingot placement barrel 300 is an annular structure consisting of an outer wall, an inner wall 301 and a barrel bottom connecting the outer wall and the inner wall 301. The outer wall is provided with dense small holes. The side of the outer wall close to the tank body is provided with a primary filtering structure 3001. The side of the inner wall 301 away from the tank body is provided with a secondary filtering tube 403. The secondary filtering tube 403 is detachably connected to the sealing cover 400. A tertiary filtering tube 500 is provided inside the secondary filtering tube 403. The tertiary filtering tube 500 is connected to the refined sodium storage tank 700 through a sodium delivery tube 709. A valve outer insulation material 502 is provided at the connection between the tertiary filtering tube 500 and the sodium delivery tube 709. Among them, the primary filtering structure 3001 is a screen, the aperture of the screen is 120 mesh, which can roughly filter the sodium slag; the secondary filtering tube 403 includes a first steel tube located at the top, a first porous tube 4031 located at the bottom, and a first bottom plate 4032, the first porous tube 4031 is detachably connected to the first steel tube and the first bottom plate 4032, the first porous tube 4031 is lower than the sodium ingot placement barrel 300, and its purpose is to purify as much crude sodium as possible after melting, the aperture of the first porous tube 4031 is 3μm, and a good balance is achieved between the purification effect and the purification efficiency. The tertiary filtering tube 500 includes a second steel tube 501 located at the top, a second porous tube 5011 located at the bottom, and a second bottom plate 5012, the second porous tube 5011 is detachably connected to the second steel tube 501 and the second bottom plate 5012. Preferably, the second porous tube 5011 is respectively connected to the second steel tube 501 and the second bottom plate 5012 by threads. The length of the second porous tube 5011 is 1 / 2 of the total length of the tertiary filter tube 500, and the pore size of the second porous tube 5011 is 0.5 μm. Among them, the secondary filter tube 403 fixedly connected to the sealing cover 400 and the tertiary filter tube 500 connected to the sealing cover 400 can be disassembled separately for easy cleaning.

[0054] The oil removal device includes an oil removal pipe 601, a buffer tank 600 and a vacuum pump 604. One end of the oil removal pipe 601 is connected to the sealing cover 400, and the other end of the oil removal pipe 601 is connected to the buffer tank 600. The vacuum pump 604 is connected to the buffer tank 600. The oil removal principle is that under heating, oil will turn into oil vapor. Under the action of negative pressure, the oil vapor is discharged from the purification tank 200, and the buffer tank 600 plays a buffering and regulating function.

[0055] The outer wall of the refined sodium storage tank 700 is a heating and heat preservation body 701, and a temperature control thermocouple 703 is arranged inside the refined sodium storage tank 700. The refined sodium storage tank 700 is connected with a sodium outlet pipe 702, a sodium delivery pipe 709 and an argon device 707. An upper liquid level 705 and a lower liquid level 704 are arranged inside the refined sodium storage tank 700, and the lower liquid level 704 is higher than the bottom of the sodium outlet pipe 702. A discharge valve 706 is arranged at the outlet of the sodium outlet pipe 702, and a heating and heat preservation layer 710 is arranged on the outer wall of the sodium delivery pipe 709. A sodium delivery valve 503 and a sodium delivery outlet valve 708 are arranged at both ends of the sodium delivery pipe 709. The air pressure can be controlled by the argon device 707, and the upper liquid level 705 and the lower liquid level 704 are used to monitor the liquid level of the refined sodium storage tank 700 to prevent the liquid level from exceeding the critical value.

[0056] An argon pressure gauge 4051, an argon inlet valve 4053, and an argon outlet valve 4052 are connected to the detachable flange on the upper part of the air pressure device 405. The two argon valves can be opened manually or started by program control.

[0057] This equipment integrates oil removal process and sodium oxide removal process. It can remove oil in the purification tank 200 and effectively intercept sodium slag through multiple filtering structures. The equipment is simple, the process flow is short, the disassembly and cleaning are easy, the safety hazard is low, and it has the characteristics of good purification effect and high efficiency.

[0058] A sodium purification process for sodium-reduced tantalum powder comprises the following steps:

[0059] S1, melting and degreasing; placing the sodium ingot into the sodium ingot placing barrel 300 in the sodium purification tank 200, starting the vacuum pump 604 and opening the vacuum valve 602, making the vacuum degree of the degreasing device 0.09MPa, the temperature between 240°C, starting the heating furnace 100 to heat the sodium purification tank 200, after the temperature reaches 260°C, keeping the temperature for 3h, obtaining liquid metallic sodium, closing the vacuum valve 602 and stopping the vacuum pump 604;

[0060] S2, purification; start the air pressure device 405 to add argon gas, keep the pressure of the sodium purification tank 200 at 0.03MPa and the temperature at 150°C. Under the argon pressure, the liquid metallic sodium flows out from the small holes on the outer wall of the sodium ingot placement barrel 300 and passes through the primary filtering structure 3001 for coarse filtration. The liquid metallic sodium after coarse filtration is respectively finely filtered through the secondary filter tube 403 and the tertiary filter tube 500 at the center of the sodium ingot placement barrel 300 to obtain refined sodium liquid. The sodium slag is trapped in the sodium purification tank 200. The refined sodium liquid is transported from the top of the tertiary filter tube 500 to the sodium delivery pipe 709. The sodium delivery pipe 709 maintains a temperature of 125°C.

[0061] S3, collect refined sodium; detect and control the pressure of the refined sodium storage tank to 0.025MPa, and the liquid level has not reached the upper liquid level 705, and open the sodium delivery valve 503, control the air pressure device 405 to make the pressure reach 0.15MPa, and the refined sodium liquid flows into the refined sodium storage tank through the sodium delivery pipe 709. When it is detected that the liquid level of the refined sodium storage tank 700 reaches the upper liquid level 705, or the pressure of the refined sodium storage tank 700 increases to 0.15MPa in a short time (that is, there is no liquid metallic sodium in the sodium purification tank 200), close the sodium delivery valve 503.

[0062] Furthermore, it also includes a slag removal step, which specifically includes opening the sealing cover 400, hanging out the old sodium ingot placement barrel 300, replacing the new sodium ingot placement barrel 300, closing the sealing cover 400, cleaning and drying the old sodium ingot placement barrel 300 for later use; when the secondary filter tube 403 and / or the tertiary filter tube 500 need to be cleaned, the first porous tube 4031 and / or the second porous tube 5011 are removed and replaced, and the old first porous tube 4031 and / or the second porous tube 5011 are cleaned and dried for later use.

[0063] The sodium purification process of the present invention can effectively remove oil and sodium oxide, has a short process flow, good purification effect, high efficiency, energy saving and environmental protection.

[0064] Embodiment 2,

[0065] like Figure 1-3 As shown, a sodium purification device for sodium reduction of tantalum powder includes a heating furnace 100, a purification tank 200, an oil removal device, an air pressure device 405, a refined sodium storage tank 700 and a sodium purification control system; the purification tank 200 is placed in the heating furnace 100, and the purification tank 200 is respectively connected to the oil removal device, the air pressure device 405 and the refined sodium storage tank 700;

[0066] The heating furnace 100 includes a furnace body, a resistance heating wire 101 and a temperature-controlling thermocouple 401 . The inner wall 301 of the furnace body is filled with a heat-insulating material 102 . The inner side of the heat-insulating material 102 is provided with a resistance heating wire 101 . The temperature-controlling thermocouple 401 extends into the interior of the purification tank 200 .

[0067] The purification tank 200 includes a tank body, a sealing cover 400, a sodium ingot placement barrel 300, a primary filtering structure 3001, a secondary filtering tube 403 and a tertiary filtering tube 500. The top of the tank body is detachably connected to the sealing cover 400. The sealing cover 400 is provided with a sodium ingot feeding port 402, a detachable temperature-controlling thermocouple 401, a liquid level gauge 404, an oil removal pipe 601, an air pressure device 405 and a secondary filtering tube 403. A sealing ring 302 is provided between the sealing ring 302 and the tank body. A supporting rib plate 201 is provided at the bottom of the tank body for placing the sodium ingot placement barrel 300. The sodium ingot feeding port 402 corresponds to the position of the sodium ingot placement barrel 300. The sodium ingot placement barrel 300 is an annular structure consisting of an outer wall, an inner wall 301 and a barrel bottom connecting the outer wall and the inner wall 301. The outer wall is provided with dense small holes. The side of the outer wall close to the tank body is provided with a primary filtering structure 3001. The side of the inner wall 301 away from the tank body is provided with a secondary filtering tube 403. The secondary filtering tube 403 is detachably connected to the sealing cover 400. A tertiary filtering tube 500 is provided inside the secondary filtering tube 403. The tertiary filtering tube 500 is connected to the refined sodium storage tank 700 through a sodium delivery tube 709. A valve outer insulation material 502 is provided at the connection between the tertiary filtering tube 500 and the sodium delivery tube 709. Among them, the primary filtering structure 3001 is a screen, the aperture of the screen is 100 mesh, which can roughly filter the sodium slag; the secondary filtering tube 403 includes a first steel tube located at the top, a first porous tube 4031 located at the bottom, and a first bottom plate 4032, the first porous tube 4031 is detachably connected to the first steel tube and the first bottom plate 4032 respectively, the first porous tube 4031 is lower than the sodium ingot placement barrel 300, and its purpose is to purify as much crude sodium as possible after melting, the aperture of the first porous tube 4031 is 5μm, and a good balance is achieved between the purification effect and the purification efficiency. The tertiary filtering tube 500 includes a second steel tube 501 located at the top, a second porous tube 5011 located at the bottom, and a second bottom plate 5012, the second porous tube 5011 is detachably connected to the second steel tube 501 and the second bottom plate 5012 respectively. Preferably, the second porous tube 5011 is respectively connected to the second steel tube 501 and the second bottom plate 5012 by threads. The length of the second porous tube 5011 is 3 / 4 of the total length of the tertiary filter tube 500, and the pore size of the second porous tube 5011 is 0.5 μm. Among them, the secondary filter tube 403 fixedly connected to the sealing cover 400 and the tertiary filter tube 500 connected to the sealing cover 400 can be disassembled separately for easy cleaning.

[0068] The oil removal device includes an oil removal pipe 601, a buffer tank 600 and a vacuum pump 604. One end of the oil removal pipe 601 is connected to the sealing cover 400, and the other end of the oil removal pipe 601 is connected to the buffer tank 600. The vacuum pump 604 is connected to the buffer tank 600. The oil removal principle is that under heating, oil will turn into oil vapor. Under the action of negative pressure, the oil vapor is discharged from the purification tank 200, and the buffer tank 600 plays a buffering and regulating function.

[0069] The outer wall of the refined sodium storage tank 700 is a heating and heat preservation body 701, and a temperature control thermocouple 703 is arranged inside the refined sodium storage tank 700. The refined sodium storage tank 700 is connected with a sodium outlet pipe 702, a sodium delivery pipe 709 and an argon device 707. An upper liquid level 705 and a lower liquid level 704 are arranged inside the refined sodium storage tank 700, and the lower liquid level 704 is higher than the bottom of the sodium outlet pipe 702. A discharge valve 706 is arranged at the outlet of the sodium outlet pipe 702, and a heating and heat preservation layer 710 is arranged on the outer wall of the sodium delivery pipe 709. A sodium delivery valve 503 and a sodium delivery outlet valve 708 are arranged at both ends of the sodium delivery pipe 709. The air pressure can be controlled by the argon device 707, and the upper liquid level 705 and the lower liquid level 704 are used to monitor the liquid level of the refined sodium storage tank 700 to prevent the liquid level from exceeding the critical value.

[0070] An argon pressure gauge 4051, an argon inlet valve 4053, and an argon outlet valve 4052 are connected to the detachable flange on the upper part of the air pressure device 405. The two argon valves can be opened manually or started by program control.

[0071] This equipment integrates oil removal process and sodium oxide removal process. It can remove oil in the purification tank 200 and effectively intercept sodium slag through multiple filtering structures. The equipment is simple, the process flow is short, the disassembly and cleaning are easy, the safety hazard is low, and it has the characteristics of good purification effect and high efficiency.

[0072] The sodium purification control system detects the temperature of the purification tank 200 through the temperature-controlled thermocouple 401, controls the heating temperature of the heating furnace 100, and at the same time, realizes the monitoring of the vacuum pump 604 and the vacuum tube of the oil removal device, the monitoring of the temperature and liquid level of the purification tank 200, the monitoring of the argon pressure gauge 4051, the argon outlet valve 4052, and the argon inlet valve 4053 in the air pressure device 405, the control of the valve, liquid level, and pressure of the refined sodium storage tank 700, and the heating control of the sodium delivery pipe 709.

[0073] A sodium purification process for sodium-reduced tantalum powder comprises the following steps:

[0074] S1, melting and degreasing; placing the sodium ingot into the sodium ingot placing barrel 300 in the sodium purification tank 200, starting the vacuum pump 604 and opening the vacuum valve 602, making the vacuum degree of the degreasing device 0.09MPa, the temperature between 240°C, starting the heating furnace 100 to heat the sodium purification tank 200, after the temperature reaches 260°C, keeping the temperature for 3h, obtaining liquid metallic sodium, closing the vacuum valve 602 and stopping the vacuum pump 604;

[0075] S2, purification; start the air pressure device 405 to add argon gas, keep the pressure of the sodium purification tank 200 at 0.03MPa and the temperature at 150°C. Under the argon pressure, the liquid metallic sodium flows out from the small holes on the outer wall of the sodium ingot placement barrel 300 and passes through the primary filtering structure 3001 for coarse filtration. The liquid metallic sodium after coarse filtration is respectively finely filtered through the secondary filter tube 403 and the tertiary filter tube 500 at the center of the sodium ingot placement barrel 300 to obtain refined sodium liquid. The sodium slag is trapped in the sodium purification tank 200. The refined sodium liquid is transported from the top of the tertiary filter tube 500 to the sodium delivery pipe 709. The sodium delivery pipe 709 maintains a temperature of 125°C.

[0076] S3, collect refined sodium; detect and control the pressure of the refined sodium storage tank to 0.025MPa, and the liquid level has not reached the upper liquid level 705, and open the sodium delivery valve 503, control the air pressure device 405 to make the pressure reach 0.15MPa, and the refined sodium liquid flows into the refined sodium storage tank through the sodium delivery pipe 709. When it is detected that the liquid level of the refined sodium storage tank 700 reaches the upper liquid level 705, or the pressure of the refined sodium storage tank 700 increases to 0.15MPa in a short time (that is, there is no liquid metallic sodium in the sodium purification tank 200), close the sodium delivery valve 503.

[0077] Furthermore, it also includes a slag removal step, which specifically includes opening the sealing cover 400, hanging out the old sodium ingot placement barrel 300, replacing the new sodium ingot placement barrel 300, closing the sealing cover 400, cleaning and drying the old sodium ingot placement barrel 300 for later use; when the secondary filter tube 403 and / or the tertiary filter tube 500 need to be cleaned, the first porous tube 4031 and / or the second porous tube 5011 are removed and replaced, and the old first porous tube 4031 and / or the second porous tube 5011 are cleaned and dried for later use.

[0078] The sodium purification process of the present invention can effectively remove oil and sodium oxide, has a short process flow, good purification effect, high efficiency, energy saving and environmental protection.

[0079] The original sodium melted in the sodium purification tank 200 and the sodium in the refined sodium tanks of each embodiment were sampled and analyzed for their impurity contents, as shown in Table 1.

[0080] Table 1:

[0081]

[0082] As shown in Table 1, the impurity content of sodium in the refined sodium storage tank 700 of Examples 1 and 2 is much lower than the impurity content of sodium in the purification tank 200, which proves that the purification equipment has excellent purification effect, effectively intercepts sodium slag sodium oxide, and has a good effect on removing impurities of other elements.

[0083] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A sodium purification device for sodium reduction of tantalum powder, characterized in that: It includes a heating furnace, a purification tank, an oil removal device, an air pressure device and a refined sodium storage tank; the purification tank is placed in the heating furnace, and the purification tank is connected to the oil removal device, the air pressure device and the refined sodium storage tank respectively; The purification tank comprises a tank body, a sealing cover, a sodium ingot placement barrel, a primary filtering structure, a secondary filtering tube and a tertiary filtering tube. The top of the tank body is detachably connected to the sealing cover. The sealing cover is provided with a sodium ingot feeding port. The tank body is provided with a sodium ingot placement barrel. The sodium ingot feeding port corresponds to the position of the sodium ingot placement barrel. The sodium ingot placement barrel is an annular structure composed of an outer wall and a barrel bottom connecting the outer wall and the inner wall. The outer wall is provided with densely distributed small holes. A primary filtering structure is provided on the side of the outer wall close to the tank body. A secondary filtering tube is provided on the side of the inner wall away from the tank body. The secondary filtering tube is detachably connected to the sealing cover. A tertiary filtering tube is provided inside the secondary filtering tube. The tertiary filtering tube is connected to the refined sodium storage tank. The secondary filter tube includes a first steel tube located at the top, a first porous tube located at the bottom, and a first bottom plate, wherein the first porous tube is lower than the sodium ingot placement barrel, and the tertiary filter tube includes a second steel tube located at the top, a second porous tube located at the bottom, and a second bottom plate; The oil removal device comprises an oil removal pipe, a buffer tank and a vacuum pump, one end of the oil removal pipe is connected to the sealing cover, the other end of the oil removal pipe is connected to the buffer tank, and the vacuum pump is connected to the buffer tank; The refined sodium storage tank is communicated with the sodium delivery pipe and the argon device. An upper liquid level and a lower liquid level are arranged inside the refined sodium storage tank. The lower liquid level is higher than the bottom of the sodium outlet pipe.

2. The sodium purification device for sodium-reduced tantalum powder according to claim 1, characterized in that: The primary filtering structure is a sieve, and the pore size of the sieve is 80-150 meshes.

3. The sodium purification device for sodium-reduced tantalum powder according to claim 1, characterized in that: The first porous tube is detachably connected to the first steel tube and the first bottom plate, respectively, and the pore size of the first porous tube is 3-15 μm.

4. The sodium purification device for sodium-reduced tantalum powder according to claim 1, characterized in that: The second porous tube is detachably connected to the second steel tube and the second bottom plate respectively.

5. The sodium purification device for sodium-reduced tantalum powder according to claim 4, characterized in that: The length of the second porous tube is 1 / 2 to 3 / 4 of the total length of the three-stage filter tube, and the pore size of the second porous tube is 0.2 to 2 μm.

6. The sodium purification device for sodium-reduced tantalum powder according to claim 1, characterized in that: The heating furnace comprises a furnace body, a resistance heating wire and a temperature-controlling thermocouple. The inner wall of the furnace body is filled with a heat-insulating material. The inner side of the heat-insulating material is provided with a resistance heating wire. The temperature-controlling thermocouple extends into the interior of the purification tank.

7. A sodium purification process for sodium reduction of tantalum powder, using the sodium purification equipment according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, melting and degreasing; placing the sodium ingot into the sodium ingot placing bucket in the sodium purification tank, starting the vacuum pump and opening the vacuum valve, making the vacuum degree of the degreasing device 0.01~0.09MPa, the temperature between 20~260℃, starting the heating furnace to heat the sodium purification tank, after the temperature reaches 250℃~270℃, keep warm for 0.5~4h, obtain liquid metallic sodium, close the vacuum valve and stop the vacuum pump; S2, purification; Start the air pressure device to add argon gas, keep the pressure of the sodium purification tank at 0.03~0.05MPa, and the temperature at 140℃~150℃. Under the argon pressure, liquid metal sodium flows out from the small holes on the outer wall of the sodium ingot placement barrel, and passes through the primary filtering structure for coarse filtration. The liquid metal sodium after coarse filtration passes through the secondary filtering tube and the tertiary filtering tube at the center of the sodium ingot placement barrel for fine filtration to obtain refined sodium liquid. The sodium slag is retained in the sodium purification tank. The refined sodium liquid is transported from the top of the tertiary filtering tube to the sodium delivery pipe, and the sodium delivery pipe is kept at a temperature of 100℃~125℃. S3, collect refined sodium; detect and control the pressure of the refined sodium storage tank to 0.025~0.03MPa, and the liquid level has not reached the upper liquid level, and open the sodium delivery valve, and the refined sodium liquid flows into the refined sodium storage tank through the sodium delivery pipe. When it is detected that the liquid level of the refined sodium storage tank reaches the upper liquid level, or there is no liquid metallic sodium in the sodium purification tank, close the sodium delivery valve.

8. A sodium purification process for sodium-reduced tantalum powder as claimed in claim 7, characterized in that: The method further includes a slag removal step, which specifically comprises opening the sealing cover, hanging out the old sodium ingot placement barrel, replacing the new sodium ingot placement barrel, closing the sealing cover, cleaning the old sodium ingot placement barrel, and drying it for later use; when it is necessary to clean the secondary filter tube and / or the tertiary filter tube, removing and replacing the first porous tube and / or the second porous tube, and cleaning and drying the old first porous tube and / or the second porous tube for later use.

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