A sodium-potassium capture device and method for continuous magnesium production

Abstract

This invention belongs to the field of metal smelting, specifically relating to a sodium-potassium collection device and method for continuous magnesium smelting. The device includes a sodium-potassium collection tube, a tube-changing device, a tube-unloading device, and a tube-changing rotor. The tube-changing rotor is rotatably connected between the tube-changing device and the tube-unloading device, which are respectively fixed to the ground by supports. The tube-changing rotor has multiple through holes, into which the sodium-potassium collection tube is placed. The rotor is driven to rotate by a motor I, and the sodium-potassium collection tube enters the vacuum chamber II of the tube-changing device for K and Na collection. After collection, the collected sodium-potassium collection tube is driven by the tube-changing rotor to the atmospheric pressure chamber II of the tube-unloading device, where it is removed. This invention, by setting a specific sodium-potassium collection device in the continuous magnesium smelting process, can effectively remove sodium and potassium impurities from magnesium vapor, improve the condensation purity of magnesium, reduce refining costs, reduce environmental pollution, and achieve high-purity, low-cost, and continuous production of metallic magnesium.

Description

Technical Field

[0001] This invention belongs to the field of metal smelting, and specifically relates to a sodium and potassium collection device and method for continuous magnesium smelting. Background Technology

[0002] China is a major producer of primary magnesium smelting and possesses the richest magnesium resources, with magnesium ore characterized by its comprehensive types, large reserves, and wide distribution. In recent years, with social development, the application of magnesium alloy materials in civilian fields, aerospace, and key military equipment has received increasing attention. Their excellent lightweight, specific strength, specific stiffness, and damping properties have led to their widespread use in automotive structural components, aircraft skins, and cabin panels. At the 6th International Magnesium Materials Expo, the release and application of new magnesium alloy preparation technologies, aerospace magnesium alloy products, and ultralight magnesium-lithium alloys further promoted the development and application of magnesium alloys.

[0003] In China, the primary magnesium smelting process mainly utilizes the Pidgeon process, a silicothermic reduction method. Magnesium-bearing ore is calcined at high temperatures to form high-temperature calcined magnesium oxide (CADA). After cooling to room temperature, the CADA is crushed, ground, and then mixed with reducing agent ferrosilicon and flux fluorite to form pellets. This process suffers from drawbacks such as high labor intensity, high energy consumption, and high carbon emissions. The relative vacuum continuous magnesium smelting process is one of the optimized processes of the Pidgeon process. It uses a flowing carrier gas to carry magnesium vapor generated in the reaction zone into a condenser, reducing the actual vapor pressure of the magnesium vapor in the reaction zone and ensuring the forward reaction. Furthermore, pelletizing is achieved by directly forming pellets from the ore raw material, realizing integrated calcination and reduction. However, while this method offers good energy-saving and emission-reduction effects, its high sodium and potassium content limits its application prospects in high-end fields, a problem that urgently needs to be addressed during the industrialization of this process.

[0004] Existing continuous magnesium smelting process ( Figure 1 In this process, the vacuum atmosphere furnace is equipped with a cooling water jacket, and a sodium-potassium trap is installed at the furnace opening. Figure 2 In the existing continuous magnesium smelting process, the existing sodium-potassium traps must be removed after each combustion of materials in the vacuum atmosphere furnace. This is time-consuming and labor-intensive, increasing the production time per cycle. Furthermore, the existing sodium-potassium traps use through holes to collect sodium and potassium, resulting in low collection efficiency. Additionally, the sodium-potassium traps are located very close to the magnesium condensation zone, allowing air to flow into the zone during disassembly, disrupting the vacuum atmosphere of the magnesium smelting environment and causing some magnesium to oxidize into magnesium oxide, reducing the purity of the crystalline magnesium. The existing continuous magnesium smelting process involves a cycle of filling – vacuuming – reaction – sodium and potassium trapping – vacuum breaking – removal of the sodium-potassium traps. During this process, the vacuum atmosphere furnace repeatedly switches between vacuum and atmospheric pressure, reducing its service life. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a sodium and potassium trapping device and method for continuous magnesium smelting. By setting up a specific sodium and potassium trapping device during the continuous magnesium smelting process, this invention can effectively remove sodium and potassium impurities from magnesium vapor, improve the condensation purity of magnesium, reduce refining costs, reduce environmental pollution, and achieve high-purity, low-cost, and continuous production of metallic magnesium.

[0006] A sodium-potassium collection device for continuous magnesium smelting includes a sodium-potassium collection tube, a tube-changing device, a tube-unloading device, and a tube-changing rotor. The tube-changing rotor is rotatably connected between the tube-changing device and the tube-unloading device, which are respectively fixed to the ground by supports. The tube-changing rotor has multiple through holes, in which the sodium-potassium collection tube is placed. The tube-changing rotor is driven to rotate by a motor I, and the sodium-potassium collection tube enters the vacuum chamber II of the tube-changing device to collect K and Na. After collection, the sodium-potassium collection tube is driven by the tube-changing rotor to the atmospheric pressure chamber II of the tube-unloading device, where it is removed.

[0007] The pressure sensor is installed inside the tube-changing impeller, and the pressure sensor is in contact with the bottom of the sodium-potassium collection tube.

[0008] The tube-changing device includes a vacuum chamber I and a vacuum chamber II. Vacuum chamber II is located above vacuum chamber I. A one-way valve I is provided on the side of vacuum chamber II. The tube-changing wheel drives the sodium-potassium collecting tube to enter vacuum chamber II through the one-way valve I. An outlet pipe port is opened on the bottom end face of vacuum chamber I and the top and bottom end faces of vacuum chamber II, respectively. Vacuum chamber I and vacuum chamber II are in a vacuum state.

[0009] The unloading device includes an atmospheric pressure chamber I and an atmospheric pressure chamber II. The atmospheric pressure chamber II is located above the atmospheric pressure chamber I. A one-way valve II is provided on the side of the atmospheric pressure chamber II. The pipe-changing wheel drives the sodium-potassium collecting tube to enter the atmospheric pressure chamber II through the one-way valve II. The bottom of the atmospheric pressure chamber II and the atmospheric pressure chamber I are respectively provided with sodium-potassium collecting tube exit holes. The atmospheric pressure chambers I and II are in an atmospheric pressure state.

[0010] A sodium-potassium trapping device for continuous magnesium smelting further includes a sodium-potassium trapping tube picking and placing device, which is used to remove or place the sodium-potassium trapping tube from or into the through hole of the tube changing wheel; the sodium-potassium trapping tube picking and placing device includes a sodium-potassium trapping tube advancing and retreating mechanism and a telescopic spring disc clamp, one end of which is fixedly connected to the telescopic spring disc clamp, and the key of the telescopic spring disc clamp is engaged in the keyway of the sodium-potassium trapping tube for picking up the sodium-potassium trapping tube.

[0011] The sodium-potassium trapping tube advancing and retreating mechanism includes a motor II, a reducer, a crank, and a fixed tube. The output shaft of motor II is connected to the reducer, the reducer is connected to the crank, a transmission rocker II is fixedly connected to the crank, the transmission rocker II is fixedly connected to the transmission rocker I, the transmission rocker I is fixedly connected to the slider, and the slider slides on the inner wall of the fixed tube. A slider connecting rod is fixedly connected to the front end of the slider, the slider connecting rod is fixedly connected to the push rod transmission shaft, and two clamping push rods are hinged to the end of the push rod transmission shaft. The ends of the clamping push rods are fixedly connected to telescopic spring disc clamps.

[0012] The inner side of the end wall of the fixed tube on the clamp push rod side is provided with a bevel, which is used to cooperate with the opening and closing of the clamp push rod.

[0013] The sodium-potassium collection tube is made of high-temperature ceramic or high-temperature alloy; the inside of the sodium-potassium collection tube is coated with a high-temperature resistant coating of 0.3mm-0.5mm thickness.

[0014] A method for sodium and potassium capture in continuous magnesium smelting includes the following steps:

[0015] Step 1. Select low-grade magnesium ore for smelting, reducing agent and flux, weigh them in a specific ratio, mix them and pelletize them to obtain pellets;

[0016] Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as a carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipeline. After calcination in the carrier gas protection environment, the pellets enter the reduction stage. After adjusting the reaction temperature, reduction is carried out to obtain magnesium vapor.

[0017] Step 3. Magnesium vapor enters the condenser for condensation, and metallic magnesium is collected. The K and Na vapors in the magnesium vapor enter the sodium-potassium collecting tube through the mixed gas inlet pipe. When the pressure sensor detects that the mass of K and Na has reached the set value, the tube-changing wheel is driven to rotate by motor I, and the sodium-potassium collecting tube enters the atmospheric pressure chamber II of the tube unloading device to remove the sodium-potassium collecting tube. At the same time, the tube-changing wheel is replenished with a new sodium-potassium collecting tube and driven into the vacuum chamber II of the tube-changing device for K and Na collection. Steps 1 to 2 are repeated to complete the collection of K and Na.

[0018] When the pressure sensor detects that the K and Na masses have not reached the set values, repeat steps 1-2. After the pellets have burned 3-4 times, if the pressure sensor still detects that the K and Na masses have not reached the set values, the tube-changing wheel will rotate the sodium-potassium collecting tube into the atmospheric pressure chamber II of the tube-unloading device via motor I and remove it. The tube-changing wheel will then insert a new sodium-potassium collecting tube and drive it into the vacuum chamber II of the tube-changing device for a new round of K and Na collection. Repeat the above process to complete the collection of K and Na.

[0019] In step 1, the MgO content in the low-grade magnesium smelting ore is <30%, including but not limited to dolomite and magnesite; the reducing agent is ferrosilicon, aluminum shavings or carbon; and the flux is fluorite.

[0020] When the reducing agent is ferrosilicon, the specific ratio by mass is dolomite:magnesite:ferrosilicon = 6.53:6.502:1.62;

[0021] The flux is added at 3% of the total mass of the pellets;

[0022] Pelletizing is carried out under pressure of 5MPa-20MPa;

[0023] In step 2, the calcination temperature is 850℃-1050℃ and the calcination time is 60min-120min; in the reduction stage, the reduction temperature is 1150℃-1400℃ and the reduction time is 60min-120min.

[0024] During the calcination and reduction stages, the type and flow rate of the carrier gas remain constant; the carrier gas flow rate is 0.05 m³ / h - 0.5 m³ / h.

[0025] The rotation speed of the tube-changing impeller is 0.2m / s-0.5m / s.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The sodium-potassium trapping device of this application adopts a unique structural design, with separate tube-changing and tube-unloading devices, which are maintained in vacuum and atmospheric pressure states respectively. This eliminates the need to disrupt the atmosphere of the vacuum atmosphere furnace body and avoids repeated changes in usage conditions, thereby extending the service life of the vacuum atmosphere furnace. Furthermore, this application utilizes a tube-changing rotor to replace the sodium-potassium trapping tubes in the tube-changing and tube-unloading devices, realizing an automatic tube-changing process. During this process, almost no outside air flows back into the condenser, indirectly improving the purity of crystalline magnesium and reducing the time required for a single production run.

[0028] 2. This application is applicable to different production scales. In large-scale production activities, when the pressure sensor at the bottom of the sodium-potassium collection tube detects that the mass of K and Na has reached the set value, the tube-changing wheel drives the sodium-potassium collection tube into the unloading device and removes it. At the same time, a new sodium-potassium collection tube is added for continuous collection. In small-scale production activities, when the pressure sensor does not detect that the mass of K and Na has reached the set value after 3-4 fuel combustion cycles, the tube-changing wheel rotates the sodium-potassium collection tube into the unloading device and removes it. At the same time, the tube-changing wheel adds a new sodium-potassium collection tube into the tube-changing device. During the entire production process, 2-3 new sodium-potassium collection tubes need to be added. The above process realizes the continuous rotation and repositioning of the sodium-potassium collection tube. At the same time, when the sodium-potassium collection tube enters the tube-changing device, only a small amount of air enters the tube-changing device, thereby reducing magnesium oxidation, increasing the reflux of K and Na, and thus ensuring the high purity of the collected magnesium.

[0029] 3. The sodium and potassium collection tube is made of high-temperature ceramic or high-temperature alloy material and coated with a high-temperature resistant coating. It can efficiently collect sodium and potassium with different saturated vapor pressures, reduce the impact of impurities on magnesium quality, and improve the purity of condensed magnesium metal.

[0030] 4. The sodium-potassium capture method of the present invention for continuous magnesium smelting involves mixing low-grade magnesium ore (such as dolomite, magnesite, etc.) with a reducing agent (ferrosilicon, aluminum scrap, or carbon) and a fluxing agent (fluorite) to form pellets. After calcination and reduction in a vertical vacuum atmosphere furnace, magnesium vapor is carried to a specific sodium-potassium capture device using a carrier gas. The sodium-potassium capture device collects sodium and potassium at different saturated vapor pressures, and high-purity metallic magnesium is collected in a condenser. The collected sodium and potassium can be further processed and recovered, reducing the impact of impurities on magnesium quality and avoiding the high energy consumption and environmental pollution problems caused by sodium and potassium impurities in subsequent refining processes.

[0031] 5. The sodium and potassium trapping device and method of this invention achieve automatic removal of sodium and potassium during continuous magnesium smelting, effectively improving the condensation purity of primary magnesium. Compared with traditional processes, it reduces the production cost of primary magnesium refining and decreases the large amount of pollutant emissions generated during refining. Simultaneously, the entire device and method enable continuous production, improving production efficiency, reducing primary magnesium refining costs, and decreasing pollutant emissions from refining. This provides a reliable technical solution for the one-step preparation of high-purity metallic magnesium, promoting the green and sustainable development of the primary magnesium smelting industry. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the existing continuous magnesium smelting process;

[0033] Figure 2 This is a schematic diagram of an existing sodium-potassium trap.

[0034] Figure 3 This is a schematic diagram of the structure of a sodium-potassium collection device for continuous magnesium smelting according to the present invention;

[0035] Figure 4 This is a left view of a sodium-potassium collection device for continuous magnesium smelting according to the present invention;

[0036] Figure 5 This is a right view of a sodium-potassium collection device for continuous magnesium smelting according to the present invention;

[0037] Figure 6 This is a schematic diagram of the pipe-changing device structure of a sodium-potassium collection device for continuous magnesium smelting according to the present invention.

[0038] Figure 7 This is a schematic diagram of the unloading device structure of a sodium-potassium collection device for continuous magnesium smelting according to the present invention.

[0039] Figure 8 This is a three-dimensional structural diagram of a sodium-potassium collection tube loading and unloading device for a sodium-potassium collection device used in continuous magnesium smelting according to the present invention.

[0040] Figure 9 This is a three-dimensional structural diagram of the sodium-potassium collection tube advance and retraction mechanism of a sodium-potassium collection device for continuous magnesium smelting according to the present invention.

[0041] Figure 10 This is a front view of the sodium-potassium collection tube advance and retraction mechanism of a sodium-potassium collection device for continuous magnesium smelting according to the present invention.

[0042] Figure 11 This is a top view of the sodium-potassium collection tube advance and retraction mechanism of a sodium-potassium collection device for continuous magnesium smelting according to the present invention.

[0043] Figure 12 This is a schematic diagram showing the positions of the rotating shaft and rotating pin on the tube-changing rotor of a sodium-potassium collection device for continuous magnesium smelting according to the present invention.

[0044] Reference numerals: 1. Mixed gas inlet pipe; 2. Pipe changing device; 201. Vacuum chamber I; 202. Vacuum chamber II; 203. One-way valve I; 204. Outlet pipe port; 205. Rotating shaft of one-way valve I; 3. Pipe changing wheel; 301. Through hole; 302. Rotating shaft; 303. Rotating pin; 4. Pipe unloading device; 401. Atmospheric pressure chamber I; 402. Atmospheric pressure chamber II; 403. One-way valve II; 404. Sodium-potassium trap exit hole; 5. Sodium-potassium trap; 6. Mixed gas outlet pipe; 7. Sodium-potassium trap handling device; 701. Sodium-potassium trap in / out mechanism; 7011. Reducer connection end; 7012. Crank; 7 013. Reducer rotating rod matching key; 7014. Reducer rotating rod; 7015. Transmission rocker arm II fastening bolt; 7016. Transmission rocker arm II; 7017. Transmission rocker arm I fastening bolt; 7018. Transmission rocker arm I; 7019. Pin shaft; 7020. Slider fastening bolt; 7021. Slider; 7022. Slider connecting rod; 7023. Push rod drive shaft; 7024. Fixture push rod; 7025. Fixed tube; 7026. Inclined surface; 702. Telescopic spring disc fixture; 8. Pressure sensor; 9. Vacuum atmosphere furnace; 10. Radiation shield; 11. Cooling water jacket; 12. Sodium and potassium trap; 13. Vacuum pumping pipeline; 14. End cap. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings.

[0046] like Figures 1-2 As shown, the existing continuous magnesium smelting process includes a vacuum atmosphere furnace 9, a radiation shield 10, a cooling water jacket 11, and a sodium-potassium trap 12. The radiation shield 10 is located in the center of the vacuum atmosphere furnace 9 to isolate thermal radiation. The sodium-potassium trap 12 is located at the furnace opening inside the vacuum atmosphere furnace 9. The cooling water jacket 11 and a vacuum pumping line 13 are connected to the outer side of the furnace body corresponding to the sodium-potassium trap 12. The vacuum pumping line 13 is connected to a vacuum pump. The furnace opening of the vacuum atmosphere furnace 9 is sealed with an end cap 14. The sodium-potassium trap 12 is... Figure 2 The structure shown.

[0047] When existing continuous magnesium smelting process units are in use,

[0048] (1) Place the dolomite into the vacuum atmosphere furnace 9, cover the end cap 14, and use a vacuum pump to evacuate the vacuum atmosphere furnace 9 to a vacuum state through the vacuum pipe 13. After evacuation, heat the furnace to 1000℃ and calcine the dolomite (main component MgCO3·CaCO3) for 1-3 hours to generate high-temperature calcined dolomite (main component MgO·CaO). The generated high-temperature calcined dolomite is cooled outdoors. After cooling, the calcined dolomite, ferrosilicon, and fluorite are crushed and mixed together, and sent to a briquetting machine to form pellets.

[0049] (2) Send the pellet into the vacuum atmosphere furnace 9, then place the radiation shield 10 inside the vacuum atmosphere furnace 9, with the radiation shield 10 10-20cm away from the edge of the pellet, then put in the sodium-potassium trap 12, 10-20cm away from the right furnace opening, and close the end cap 14 tightly. Then use the vacuum pump to evacuate the vacuum atmosphere furnace 9 to a vacuum state through the vacuum pipe 13. After reaching the vacuum state, the vacuum atmosphere furnace 9 starts to heat up from room temperature to 1300℃ to carry out the reduction reaction. The reduction time is 10-14 hours.

[0050] (3) After the pellets undergo a high-temperature reduction reaction, magnesium vapor will be generated. The impurities sodium and potassium metals inside the pellets will also form sodium vapor and potassium vapor. After the magnesium vapor, sodium vapor and potassium vapor flow through the radiation shield 10, the magnesium vapor will condense and crystallize under the heat exchange of the cooling water jacket 11 to obtain condensed magnesium. The sodium vapor and potassium vapor continue to flow forward and are condensed on the sodium and potassium collector 12.

[0051] (4) After the reaction is complete, open the end cap 14 and quickly hook out the sodium-potassium trap 12 with the furnace hook and drop it on the ground. Sodium and potassium will burn when they come into contact with air, but the amount is small and there is no danger. This is how it is done in industry. Then take out the condensed magnesium, and then take out the radiation shield 10 and the reduced pellets in sequence. Finally, clean the entire equipment and repeat the above process for repeated production.

[0052] The existing continuous magnesium smelting process requires the removal of the sodium-potassium trap 12 for each reduction cycle, and it repeatedly undergoes switching between vacuum and atmospheric pressure, resulting in a short equipment lifespan. In addition, the sodium-potassium trap 12 is very close to the magnesium condensation zone, and air will flow into the magnesium condensation zone during the disassembly of the sodium-potassium trap 12, which will disrupt the vacuum atmosphere of the magnesium smelting environment and reduce the purity of the crystalline magnesium.

[0053] like Figures 3-12 As shown, a sodium-potassium collection device for continuous magnesium smelting includes a sodium-potassium collection pipe 5, a pipe-changing device 2, a pipe-unloading device 4, and a pipe-changing impeller 3. The pipe-changing impeller 3 is rotatably connected between the pipe-changing device 2 and the pipe-unloading device 4. The pipe-changing device and the pipe-unloading device are located on the outside of the pipe-changing impeller 3 and are symmetrically arranged along the center of the pipe-changing impeller 3. The pipe-changing device 2 and the pipe-unloading device 4 are respectively fixed to the ground by supports. The pipe-changing impeller 3 has multiple through holes 301, and the sodium-potassium collection pipe 5 is placed in the through holes 301. The pipe-changing impeller 3 is driven to rotate by a motor I. The sodium-potassium collecting tube 5 enters the vacuum chamber II 202 of the tube changing device 2 to collect K and Na. At this time, the upper end of the sodium-potassium collecting tube 5 is connected to the mixed gas inlet pipe 1, and the lower end of the sodium-potassium collecting tube 5 is connected to the mixed gas outlet pipe 6. The mixed gas inlet pipe 1 is fixedly connected to the condenser, the condenser is connected to the vertical vacuum atmosphere furnace, and the mixed gas outlet pipe 6 is fixedly connected to the circulation pump. After the collection is completed, the sodium-potassium collecting tube 5 is driven by the tube changing wheel 3 to the atmospheric pressure chamber II 402 of the tube unloading device 4, and the sodium-potassium collecting tube 5 is taken out.

[0054] In this embodiment, the sodium-potassium collecting tube 5 is used to collect sodium and potassium, and the tube-changing wheel 3 is used to replenish and reposition the sodium-potassium collecting tube 5. The new sodium-potassium collecting tube 5 is placed in the through hole 301 of the tube-changing wheel 3. By rotating the tube-changing wheel 3, it is placed into the vacuum chamber II 202 of the tube-changing device 2 for the collection of sodium and potassium. The sodium-potassium collecting tube 5 after collecting sodium and potassium is transmitted to the atmospheric pressure chamber II 402 of the tube-unloading device 4 through the tube-changing wheel 3, and the collected sodium-potassium collecting tube 5 is taken out.

[0055] In this embodiment, the tube-changing wheel 3 is provided with 6 through holes 301, the specifications of which match the sodium-potassium collection tube 5; the tube-changing wheel 3 is provided with a rotating shaft 302 in the middle, one end of which is provided with a rotating pin 303, and the other end is connected to the motor I. The rotating pin 303 moves in the arc-shaped area in the middle of the rotating shaft 302 of the tube-changing wheel 3, thereby driving the tube-changing wheel 3 to rotate. The tube-changing wheel 3 rotates 60° clockwise each time, and connects to a new sodium-potassium collection tube 5 at a speed of 0.2m / s-0.5m / s. The tube-changing connection switching time is 0.1s-0.5s, and the sodium-potassium collection tube 5 is replaced during the rotation process;

[0056] The sodium-potassium collection tube 5 is made of high-temperature ceramic or high-temperature alloy; the sodium-potassium collection tube 5 is coated with a high-temperature resistant coating of 0.3mm-0.5mm thickness; in this embodiment, the sodium-potassium collection tube 5 has a length of 40mm-55mm, a diameter of 18mm-25mm, and a wall thickness of 1-3mm.

[0057] In this embodiment, a tube-changing device 2 and a tube-unloading device 4 are respectively provided, and they are kept in a vacuum state and an atmospheric pressure state respectively. This does not require disrupting the atmosphere of the vacuum atmosphere furnace body, and also avoids repeated replacement of the usage state, thereby extending the service life of the vacuum atmosphere furnace. In addition, this application uses a tube-changing rotor 3 to replace the sodium-potassium collecting tube 5 in the tube-changing device 2 and the tube-unloading device 4, realizing an automatic tube-changing process. During this process, almost no outside air flows back into the condenser, indirectly improving the purity of crystalline magnesium.

[0058] The tube-changing impeller 3 is equipped with a pressure sensor 8. The bottom of the sodium-potassium collecting tube 5 contacts the pressure sensor 8. For large-scale production activities, when the pressure sensor 8 detects that the mass of K and Na has reached the set value, the tube-changing impeller 3 is driven to rotate by motor I, and the sodium-potassium collecting tube 5 enters the atmospheric pressure chamber II 402 of the unloading device 4 and is removed. At the same time, a new sodium-potassium collecting tube 5 is added for continuous collection. For small-scale production activities, when the pressure sensor 8 still does not detect that the mass of K and Na has reached the set value after the material has been burned 3-4 times, the tube-changing impeller 3 is also driven to rotate by motor I. Ⅰ The rotating mechanism drives the sodium-potassium collection tube 5 to be rotated into the unloading device 4 and removed. At the same time, the tube-changing wheel 3 inserts a new sodium-potassium collection tube 5 into the tube-changing device 2. During the entire production process, 2 to 3 new sodium-potassium collection tubes 5 need to be added, that is, the replacement cycle of the sodium-potassium collection tube 5 is 2 to 3 times. By adding new sodium-potassium collection tubes 5, the purity of the collected magnesium can be higher. The number of tube replacements is based on the collection capacity of the sodium-potassium collection tube 5 and the accumulation of sodium and potassium. The setting of different pressure systems helps to optimize the collection process, improve the sodium-potassium removal efficiency and the overall stability of the system.

[0059] The tube-changing device 2 includes a vacuum chamber I 201 and a vacuum chamber II 202. Vacuum chamber II 202 is located above vacuum chamber I 201. Vacuum chamber I 201 is connected to a vacuum pump. A one-way valve I 203 is provided on the side of vacuum chamber II 202. The tube-changing wheel 3 drives the sodium-potassium collecting tube 5 into vacuum chamber II 202 through the one-way valve I 203. An outlet pipe port 204 is opened on the bottom end face of vacuum chamber I 201. The top and bottom end faces of vacuum chamber II 202 are... An outlet pipe port 204 is provided. The outlet pipe port 204 of the mixed gas outlet pipe 6 extends into the bottom end face of the vacuum chamber II 202 and the vacuum chamber I 201 and contacts the bottom of the sodium-potassium trapping pipe 5 on the pipe changing wheel 3. The outlet pipe port 204 of the mixed gas inlet pipe 1 extends into the top end face of the vacuum chamber II 202 and contacts the top of the sodium-potassium trapping pipe 5. The vacuum chamber I 201 and the vacuum chamber II 202 are in a vacuum state and the vacuum atmosphere pressure is 0.001Pa-0.1Pa.

[0060] In this embodiment, the one-way valve I 203 only allows the sodium-potassium collecting tube 5 to pass through in one direction. The one-way valve I 203 is connected to the outer shell of the vacuum chamber II 202 through the one-way valve I rotating shaft 205. The mixed gas inlet pipe 1 is sealed to the outlet pipe port 204 on the top end face of the vacuum chamber II 202, and the mixed gas outlet pipe 6 is sealed to the outlet pipe port 204 on the bottom end face of the vacuum chamber I 201. The vacuum chambers I 201 and II 202 must be kept in a vacuum state. Specifically, the sodium-potassium collecting tube 5 enters the vacuum chamber II 202 under the drive of the tube changing wheel 3. At this time, the sodium-potassium collecting tube... The two ends of 5 are respectively inserted into the outlet pipe ports 204 at the top and bottom of the vacuum chamber II 202 and connected to the mixed gas inlet pipe 1 and the mixed gas outlet pipe 6. The mixed gas inlet pipe 1 extends into the outlet pipe port 204 at the top of the vacuum chamber II 202 and is connected to the sodium-potassium trapping pipe 5. The mixed gas outlet pipe 6 is connected to the sodium-potassium trapping pipe 5 at the outlet pipe port 204. Since the mixed gas outlet pipe 6 and the sodium-potassium trapping pipe 5 are not sealed, when it is necessary to maintain a vacuum state, the air in the vacuum chamber I 201 can be extracted by the vacuum pump, so that the air in the vacuum chamber II 202 can be extracted to maintain a vacuum state.

[0061] The unloading device 4 includes an atmospheric pressure chamber I 401 and an atmospheric pressure chamber II 402. The atmospheric pressure chamber II 402 is located above the atmospheric pressure chamber I 401. A one-way valve II 403 is provided on the side of the atmospheric pressure chamber II 402. The pipe changing wheel 3 drives the sodium-potassium collecting pipe 5 into the atmospheric pressure chamber II 402 through the one-way valve II 403. The bottom of the atmospheric pressure chamber II 402 and the atmospheric pressure chamber I 401 are respectively provided with sodium-potassium collecting pipe exit holes 404. The atmospheric pressure chambers I 401 and II 402 are in a normal pressure state.

[0062] In this embodiment, the potassium trapping tube removal and placement device passes through the sodium-potassium trapping tube exit hole 404 at the bottom of the atmospheric pressure chamber II 402 and the atmospheric pressure chamber I 401 and connects to the sodium-potassium trapping tube 5, thereby removing the sodium-potassium trapping tube 5.

[0063] A sodium-potassium collection device for continuous magnesium smelting also includes a sodium-potassium collection tube taking and placing device 7, which is used to take out or put into the sodium-potassium collection tube 5 from the through hole 301 of the tube changing wheel 3.

[0064] The sodium-potassium collection tube picking and placing device 7 includes a sodium-potassium collection tube advancing and retreating mechanism 701 and a telescopic spring disc clamp 702. One end of the sodium-potassium collection tube advancing and retreating mechanism 701 is fixedly connected to the telescopic spring disc clamp 702. The key of the telescopic spring disc clamp 702 is engaged in the keyway of the sodium-potassium collection tube 5 for picking up the sodium-potassium collection tube 5.

[0065] In this embodiment, the sodium-potassium trapping tube advance and retraction mechanism 701 presses down the telescopic spring disc clamp 702, moving it to the tail of the sodium-potassium trapping tube 5. The sodium-potassium trapping tube advance and retraction mechanism 701 then releases the telescopic spring disc clamp 702, causing the matching key of the telescopic spring disc clamp 702 to engage in the keyway inside the sodium-potassium trapping tube 5, and further driving the sodium-potassium trapping tube 5 into the tube-changing wheel 3. Subsequently, the sodium-potassium trapping tube advance and retraction mechanism 701 presses down the telescopic spring disc clamp 702, causing the matching key of the telescopic spring disc clamp 702 to disengage from the keyway inside the sodium-potassium trapping tube 5. Then, the sodium-potassium trapping tube advance and retraction mechanism 701 moves back and exits the tube-changing wheel 3.

[0066] After the sodium-potassium collecting tube 5 is installed into the tube-changing wheel 3, the rotating shaft 302 drives the tube-changing wheel 3 to rotate through the rotating pin 303 and the arc-shaped area, thus transferring the sodium-potassium collecting tube 5 into the vacuum chamber II 202 of the tube-changing device 2 via the one-way valve I 203. Once inside the vacuum chamber II 202 of the tube-changing device 2, the sodium-potassium collecting tube 5 contacts the pressure sensor at the bottom of the tube-changing wheel 3. After a certain amount of sodium and potassium is collected, the tube is unloaded.

[0067] The tube-changing wheel 3 is driven to rotate by the rotating shaft 302 through the rotating pin of the tube-changing wheel 3 engaging with the arc-shaped area, which rotates the sodium-potassium collecting tube 5 into the atmospheric pressure chamber II 402 of the tube unloading device 4 via the one-way valve II 403; the sodium-potassium collecting tube advance and retraction mechanism 701 moves towards the sodium-potassium collecting tube 5, and the telescopic spring disc clamp 702 compresses downward, so that the matching key of the telescopic spring disc clamp 702 engages with the keyway inside the sodium-potassium collecting tube 5; then the sodium-potassium collecting tube advance and retraction mechanism 701 drives the sodium-potassium collecting tube 5 away from the tube-changing wheel 3, completing the tube unloading operation.

[0068] The sodium-potassium trapping tube advancing and retreating mechanism 701 includes a motor II, a reducer, a crank 7012, and a fixed tube 7025. The output shaft of the motor II is connected to the reducer, the reducer is connected to the crank 7012, a transmission rocker arm II 7016 is fixedly connected to the crank 7012, the transmission rocker arm II 7016 is fixedly connected to the transmission rocker arm I 7018, the transmission rocker arm I 7018 is fixedly connected to the slider 7021, and the slider 7021 slides on the inner wall of the fixed tube 7025. The front end of the slider 7021 is fixedly connected to a slider connecting rod 7022, the slider connecting rod 7022 is fixedly connected to a push rod drive shaft 7023, the end of the push rod drive shaft 7023 is hinged to two clamp push rods 7024, the end of the clamp push rods 7024 is fixedly connected to a telescopic spring disc clamp 702, and the inner side of the end wall of the fixed tube 7025 on the side of the clamp push rod 7024 is provided with a slope 7026 for cooperating with the opening and closing of the clamp push rods 7024.

[0069] In this embodiment, the motor is connected to a reducer to reduce the high speed of the motor. The reducer is connected to the reducer input terminal 7011. The rotation of the motor drives the reducer to rotate, which in turn drives the reducer rotating rod 7014 to rotate. The reducer rotating rod 7014 drives the crank 7012 to rotate via the reducer rotating rod matching key 7013. The crank 7012 drives the transmission rocker arm II 7016 to rotate via the transmission rocker arm II fastening bolt 7015. The transmission rocker arm II 7016 drives the transmission rocker arm I 7018 to move via the transmission rocker arm I fastening bolt 7017. The movement of the transmission rocker arm I 7018 drives the slider 7021 to reciprocate within the fixed tube. The slider 7021 and the slider connecting rod 7022 are connected by... The slider 7021 is connected by welding, so the slider connecting rod 7022 reciprocates. The slider connecting rod 7022 drives the push rod transmission shaft 7023 to reciprocate through the slider fastening bolt 7020. The push rod transmission shaft 7023 drives the clamp push rod 7024 to move up and down through the pin 7019. The clamp push rod 7024 is connected to the telescopic spring disc clamp 702 by welding. The clamp push rod 7024 drives the telescopic spring disc clamp 702 to clamp and release the sodium-potassium collection tube 5. During the opening and closing process of the clamp push rod 7024, it moves along the inclined surface 7026 at the bottom of the fixed tube 7025, which can ensure the stable opening and closing of the clamp push rod 7024.

[0070] The advancing speed of the sodium-potassium trapping tube advance and retracting mechanism 701 is 0.5m / s-0.8m / s, ensuring that the sodium-potassium trapping tube 5 can be replaced quickly and stably to meet the sodium-potassium trapping requirements in the continuous magnesium smelting process.

[0071] This invention provides a method for sodium and potassium capture in continuous magnesium smelting, comprising the following steps:

[0072] Step 1. Select low-grade magnesium smelting ore (MgO content < 30%) (including but not limited to dolomite and magnesite), reducing agent (ferrosilicon, aluminum scrap or carbon), and fluorite flux (3% of the total mass of the pellets). Weigh and mix them in a specific ratio: dolomite: magnesite: ferrosilicon = 6.53: 6.502: 1.62. Then pelletize under a pressure of 5MPa-20MPa.

[0073] Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipe 6. The pellets are calcined in a vacuum environment, with the calcination temperature controlled at 850℃-1050℃ and the carrier gas flow rate controlled at 0.05m³ / h-0.5m³ / h, for a continuous calcination of 60min-120min. Then, the reduction stage is entered, with the temperature adjusted to 1150℃-1400℃ and the carrier gas flow rate maintained at 0.05m³ / h-0.5m³ / h, for a reduction of 60min-120min.

[0074] Step 3. After the reduction reaction begins, adjust the carrier gas flow rate to 0.05 m³ / h-0.50 m³ / h so that the generated magnesium vapor leaves the reaction zone and is collected in the condenser. The K and Na vapors in the magnesium vapor enter the sodium-potassium trapping tube 5 through the mixed gas inlet pipe 1 for collection.

[0075] When the pressure sensor 8 detects that the K and Na masses have reached the set values, the tube-changing wheel 3 is driven to rotate by the motor I, and the sodium-potassium collecting tube 5 enters the atmospheric pressure chamber II 402 of the tube-unloading device 4 to remove the sodium-potassium collecting tube 5; at the same time, the tube-changing wheel 3 is replenished with a new sodium-potassium collecting tube 5, and it is driven into the vacuum chamber II 202 of the tube-changing device 2 for K and Na collection. Steps 1 to 2 are repeated to complete the collection of K and Na.

[0076] When the pressure sensor 8 detects that the K and Na mass has not reached the set value, steps 1 to 2 are repeated. After the pellets are burned 3 to 4 times, if the pressure sensor 8 detects that the K and Na mass has not reached the set value, the tube changing wheel 3 rotates the sodium-potassium collecting tube 5 through the motor I to the atmospheric pressure chamber II 402 of the tube unloading device 4 to remove it. The tube changing wheel 3 is then filled with a new sodium-potassium collecting tube 5 and driven into the vacuum chamber II 202 of the tube changing device 2 for a new round of K and Na collection. The above process is repeated to complete the collection of K and Na.

[0077] Specifically: the tube-changing rotor 3 rotates the sodium-potassium collecting tube 5 into the vacuum chamber II 202 of the tube-changing device 2. The upper end of the sodium-potassium collecting tube 5 is sealed and connected to the mixed gas inlet pipe 1. Both the vacuum chamber I 201 and the vacuum chamber II 202 of the tube-changing device 2 are maintained in a vacuum state. During the collection process, the bottom of the sodium-potassium collecting tube 5 contacts the pressure sensor 8 inside the vacuum chamber II 202 of the tube-changing device 2 to monitor the accumulated sodium and potassium mass in the sodium-potassium collecting tube 5 in real time.

[0078] For large-scale production activities, when the pressure sensor 8 detects that the accumulated mass of K and Na in the sodium-potassium trapping tube 5 reaches 1‰~3‰ of the total mass of the pellets, the tube-changing wheel 3 rotates clockwise and connects a brand new sodium-potassium trapping tube 5 at a speed of 0.2m / s-0.5m / s. For small-scale production activities, after 3~4 material combustions, when the pressure sensor 8 detects that the accumulated mass of K and Na in the sodium-potassium trapping tube 5 continues to reach 1‰~3‰ of the total mass of the pellets, the tube-changing wheel 3 also rotates to replace the sodium-potassium trapping tube 5. The sodium-potassium trapping tube 5 needs to undergo 2~3 tube-changing operations. Each time the sodium-potassium trapping tube 5 is replaced, the sodium-potassium trapping tube 5 that has captured saturated vapor pressure metal is taken out, and a clean sodium-potassium trapping tube 5 is filled into the tube-changing wheel 3. The sodium-potassium trapping pipe 5 connected to the condenser is in the same insulation zone as the sodium-potassium trapping pipe 5 to be connected. The temperature of this zone is controlled at 800℃, and the insulation zone is made of calcium aluminate refractory.

[0079] In step 1, the selection of low-grade magnesium smelting ore can be flexibly adjusted according to the actual resource situation. The proportion of different raw ores and the uniformity of mixing with reducing agent and flux will affect the subsequent reaction effect.

[0080] In step 2, the temperature, carrier gas flow rate, and time parameters of the calcination and reduction stages in the vertical vacuum atmosphere furnace need to be precisely controlled according to the characteristics of the raw materials and the reaction process to ensure that the pellets react fully and improve the magnesium production efficiency.

[0081] In step 3, the precise adjustment of the carrier gas flow rate is crucial for the delivery of magnesium vapor and the effective separation of sodium and potassium in different collectors. The working effect of the sodium and potassium collection device is closely related to factors such as the structure of the collector itself and the performance of the collection tube.

[0082] In step 4, the accuracy of the pressure sensor directly affects the accuracy of the tube replacement operation. The rotation speed of the tube replacement wheel shaft and the tube replacement speed must be matched to ensure that the entire tube replacement process is stable and reliable and does not affect the vacuum environment and collection efficiency of the system.

[0083] In this invention, a vertical vacuum atmosphere furnace is used as the calcination and reduction reaction site for magnesium smelting. It consists of an outer high-strength furnace shell and an inner high-temperature refractory layer, with heating elements installed between the shell and the refractory layer. A raw material inlet is located at the top of the furnace, and a waste outlet is located at the bottom. A condenser is connected to the mixed gas outlet above the vertical vacuum atmosphere furnace. The condenser employs a high-efficiency condensation structure with multiple layers of condensing plates inside. Temperature is controlled by a circulating cooling medium to ensure that magnesium vapor is fully condensed into liquid magnesium for collection. In this invention, the vertical vacuum atmosphere furnace, condenser, and circulating pump are all existing products in the art, and only those capable of performing the corresponding functions are required.

[0084] Example 1

[0085] This embodiment provides a sodium-potassium capture method for continuous magnesium smelting, comprising the following steps:

[0086] Step 1. Using dolomite and magnesite as low-grade magnesium ore (MgO content < 30%), ferrosilicon as reducing agent, and fluorite as flux, the materials are weighed and mixed according to the mass ratio of dolomite:magnesite:ferrosilicon:fluorite = 6.53:6.502:1.62:0.44. The mixture is then pelletized under a pressure of 5 MPa to 20 MPa to obtain pellets. In the pellets, the mass of fluorite accounts for 3% of the total mass of the pellets.

[0087] Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipe 6. The pellets are calcined at 900℃ for 60 min under the protection of the carrier gas, and then reduced at 1250℃ for 60 min to obtain magnesium vapor.

[0088] Step 3. Inert gas is introduced into the reaction environment at a flow rate of 0.1 m³ / h. Magnesium vapor enters the condenser for condensation under the action of inert gas, and metallic magnesium is collected. K and Na in magnesium vapor enter the sodium-potassium trapping tube 5 through the mixed gas inlet pipe 1 for collection.

[0089] When the pressure sensor 8 detects that the K and Na masses have not reached the set values ​​after the pellets have burned twice, the tube-changing wheel 3 rotates 60° clockwise into the tube-unloading device 4, and the sodium-potassium collecting tube 5 is removed. The tube-changing wheel 3 then connects to a brand new sodium-potassium collecting tube 5 at a speed of 0.1 m / s. During the entire production process, the sodium-potassium collecting tube 5 is replaced twice, with a tube-changing connection switching time of 0.1 s. During the conversion of the sodium-potassium collecting tube 5, the vacuum chamber II 202 of the tube-changing device 2 is maintained in a vacuum state with a vacuum atmosphere pressure of 0.001 Pa. The purity of the crystalline magnesium finally collected reaches 90.5%.

[0090] Example 2

[0091] This embodiment provides a sodium-potassium capture method for continuous magnesium smelting, comprising the following steps:

[0092] Step 1. Using dolomite and magnesite as low-grade magnesium smelting raw ore (MgO content <30%), ferrosilicon as reducing agent, and fluorite as flux, the materials are weighed and mixed according to the mass ratio of dolomite:magnesite:ferrosilicon:fluorite = 6.53:6.502:1.62:0.44. The mixture is then pelletized under a pressure of 5MPa~20MPa to obtain pellets. Step 2. The pellets are placed in a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipe 6. The pellets are calcined at 900℃ for 60min under the protection of the carrier gas, and then reduced at 1250℃ for 60min to obtain magnesium vapor.

[0093] Step 3. Inert gas is introduced into the reaction environment at a flow rate of 0.1 m³ / h. Magnesium vapor enters the condenser for condensation under the action of inert gas, and metallic magnesium is collected. K and Na in magnesium vapor enter the sodium-potassium trapping tube 5 through the mixed gas inlet pipe 1 for collection.

[0094] When the pressure sensor 8 detects that the K and Na masses have not reached the set values ​​after the pellets have burned three times, the tube-changing wheel rotates 60° clockwise into the tube-unloading device 4, and the sodium-potassium collecting tube 5 is removed. The tube-changing wheel 3 then connects to a brand new sodium-potassium collecting tube 5 at a speed of 0.2 m / s. During the entire production process, the sodium-potassium collecting tube 5 is replaced three times, with a tube-changing connection and switching time of 0.2 s. During the conversion of the sodium-potassium collecting tube 5, the vacuum chamber II 202 of the tube-changing device 2 is maintained in a vacuum state with a vacuum atmosphere pressure of 0.001 Pa. The purity of the crystalline magnesium finally collected reaches 92.7%.

[0095] Example 3

[0096] This embodiment provides a sodium-potassium capture method for continuous magnesium smelting, comprising the following steps:

[0097] Step 1. Using dolomite and magnesite as low-grade magnesium smelting raw ore (MgO content <30%), ferrosilicon as reducing agent, and fluorite as flux, the mixture is weighed and mixed according to the mass ratio of dolomite:magnesite:ferrosilicon:fluorite = 10.4:0.94:2.5:0.44, and pelletized under a pressure of 5MPa~20MPa to obtain pellets;

[0098] Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipe 6. The pellets are calcined at 900℃ for 60 min under the protection of the carrier gas, and then reduced at 1250℃ for 60 min to obtain magnesium vapor.

[0099] Step 3. Inert gas is introduced into the reaction environment at a flow rate of 0.1 m³ / h. Magnesium vapor enters the condenser for condensation under the action of inert gas, and metallic magnesium is collected. K and Na in magnesium vapor enter the sodium-potassium trap through the mixed gas inlet pipe 1 for collection.

[0100] The pressure sensor monitors the K and Na mass in the collection tube. When the collected K and Na mass reaches 1‰ of the total mass of the pellets, the tube-changing wheel rotates 60° clockwise into the atmospheric pressure chamber II 402 of the tube-unloading device 4, and the sodium-potassium collection tube 5 is removed. The tube-changing wheel 3 connects to a brand new sodium-potassium collection tube 5 at a speed of 0.1 m / s and enters the vacuum chamber II 202 of the tube-changing device 2 for K and Na collection. The tube-changing connection and switching time is 0.1 s. During the conversion of the sodium-potassium collection tube 5, the vacuum chamber II 202 of the tube-changing device 2 is maintained in a vacuum state with a vacuum atmosphere pressure of 0.001 Pa. The purity of the finally collected crystalline magnesium reaches 86.40%.

[0101] Example 4

[0102] This embodiment provides a sodium-potassium capture method for continuous magnesium smelting, comprising the following steps:

[0103] Step 1. Using dolomite and magnesite as low-grade magnesium smelting raw ore (MgO content <30%), ferrosilicon as reducing agent, and fluorite as flux, the mixture is weighed and mixed according to the mass ratio of dolomite:magnesite:ferrosilicon:fluorite = 10.4:0.94:2.5:0.44, and pelletized under a pressure of 5MPa~20MPa to obtain pellets;

[0104] Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipe 6. The pellets are calcined at 900℃ for 60 min under the protection of the carrier gas, and then reduced at 1250℃ for 60 min to obtain magnesium vapor.

[0105] Step 3. Inert gas is introduced into the reaction environment at a flow rate of 0.1 m³ / h. Magnesium vapor enters the condenser for condensation under the action of inert gas, and metallic magnesium is collected. K and Na in magnesium vapor enter the sodium-potassium trapping tube 5 through the mixed gas inlet pipe 1 for collection.

[0106] Pressure sensor 8 monitors the K and Na mass in the collection tube. When the collected K and Na mass reaches 2‰ of the total mass of the pellets, the tube-changing wheel 3 rotates 60° clockwise into the atmospheric pressure chamber II 402 of the tube-unloading device 4, and the sodium-potassium collection tube 5 is removed. The tube-changing wheel 3 connects to a brand new sodium-potassium collection tube 5 at a speed of 0.2 m / s and enters the vacuum chamber II 202 of the tube-changing device 2 for K and Na collection. The tube-changing connection switching time is 0.2 s. During the conversion of the sodium-potassium collection tube 5, the vacuum chamber II 202 of the tube-changing device 2 is maintained in a vacuum state with a vacuum atmosphere pressure of 0.001 Pa. The purity of the finally collected crystalline magnesium reaches 88.20%.

[0107] Example 5

[0108] This embodiment provides a sodium-potassium capture method for continuous magnesium smelting, comprising the following steps:

[0109] Step 1. Using dolomite and magnesite as low-grade magnesium smelting raw ore (MgO content <30%), ferrosilicon as reducing agent, and fluorite as flux, the mixture is weighed and mixed according to the mass ratio of dolomite:magnesite:ferrosilicon:fluorite = 10.4:0.94:2.5:0.44, and pelletized under a pressure of 5MPa~20MPa to obtain pellets;

[0110] Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipe 6. The pellets are calcined at 900℃ for 60 min under the protection of the carrier gas, and then reduced at 1250℃ for 60 min to obtain magnesium vapor.

[0111] Step 3. Inert gas is introduced into the reaction environment at a flow rate of 0.1 m³ / h. Magnesium vapor enters the condenser for condensation under the action of inert gas, and metallic magnesium is collected. K and Na in magnesium vapor enter the sodium-potassium trapping tube 5 through the mixed gas inlet pipe 1 for collection.

[0112] Pressure sensor 8 monitors the K and Na mass in the collection tube. When the collected K and Na mass reaches 3‰ of the total mass of the pellets, the tube-changing wheel 3 rotates 60° clockwise into the atmospheric pressure chamber II 402 of the tube-unloading device 4. The sodium-potassium collection tube 5 is removed, and the tube-changing wheel 3 connects to a brand new sodium-potassium collection tube 5 at a speed of 0.3 m / s. It then enters the vacuum chamber II 202 of the tube-changing device 2 for K and Na collection. The tube-changing connection and switching time is 0.3 s. During the conversion of the sodium-potassium collection tube 5, the vacuum chamber II 202 of the tube-changing device 2 is maintained in a vacuum state with a vacuum atmosphere pressure of 0.001 Pa. The purity of the finally collected crystalline magnesium reaches 89.70%.

Claims

1. A sodium-potassium collection device for continuous magnesium smelting, characterized in that, The device includes a sodium-potassium collecting tube, a tube-changing device, a tube-unloading device, and a tube-changing wheel. The tube-changing wheel is rotatably connected between the tube-changing device and the tube-unloading device. The tube-changing device and the tube-unloading device are fixed to the ground by brackets. The tube-changing wheel has multiple through holes, in which the sodium-potassium collecting tube is placed. The tube-changing wheel is driven to rotate by motor I. The sodium-potassium collecting tube enters the vacuum chamber II of the tube-changing device to collect K and Na. After collection, the sodium-potassium collecting tube is driven by the tube-changing wheel to the atmospheric pressure chamber II of the tube-unloading device, where the sodium-potassium collecting tube is removed. The pressure sensor is installed inside the tube-changing impeller, and the bottom of the sodium-potassium collection tube is in contact with the pressure sensor. The tube-changing device includes a vacuum chamber I and a vacuum chamber II. Vacuum chamber II is located above vacuum chamber I. A one-way valve I is provided on the side of vacuum chamber II. The tube-changing wheel drives the sodium-potassium collecting tube to enter vacuum chamber II through the one-way valve I. An outlet pipe port is opened on the bottom end face of vacuum chamber I and the top and bottom end faces of vacuum chamber II, respectively. Vacuum chamber I and vacuum chamber II are in a vacuum state. The unloading device includes an atmospheric pressure chamber I and an atmospheric pressure chamber II. The atmospheric pressure chamber II is located above the atmospheric pressure chamber I. A one-way valve II is provided on the side of the atmospheric pressure chamber II. The pipe-changing wheel drives the sodium-potassium collecting tube to enter the atmospheric pressure chamber II through the one-way valve II. The bottom of the atmospheric pressure chamber II and the atmospheric pressure chamber I are respectively provided with sodium-potassium collecting tube exit holes. The atmospheric pressure chambers I and II are in an atmospheric pressure state.

2. The sodium-potassium collection device for continuous magnesium smelting according to claim 1, characterized in that, It also includes a sodium-potassium trapping tube picking and placing device, which is used to take out or put into the sodium-potassium trapping tube from the through hole of the tube changing wheel; the sodium-potassium trapping tube picking and placing device includes a sodium-potassium trapping tube advancing and retreating mechanism and a telescopic spring disc clamp, one end of the sodium-potassium trapping tube advancing and retreating mechanism is fixedly connected to the telescopic spring disc clamp, and the key of the telescopic spring disc clamp is engaged in the keyway of the sodium-potassium trapping tube for picking up the sodium-potassium trapping tube.

3. A sodium-potassium collection device for continuous magnesium smelting according to claim 2, characterized in that, The sodium-potassium trapping tube advancing and retreating mechanism includes a motor II, a reducer, a crank, and a fixed tube. The output shaft of motor II is connected to the reducer, the reducer is connected to the crank, a transmission rocker II is fixedly connected to the crank, the transmission rocker II is fixedly connected to the transmission rocker I, the transmission rocker I is fixedly connected to the slider, and the slider slides on the inner wall of the fixed tube. A slider connecting rod is fixedly connected to the front end of the slider, the slider connecting rod is fixedly connected to the push rod transmission shaft, and two clamping push rods are hinged to the end of the push rod transmission shaft. The ends of the clamping push rods are fixedly connected to telescopic spring disc clamps.

4. A sodium-potassium collection device for continuous magnesium smelting according to claim 3, characterized in that, The inner side of the end wall of the fixed tube on the clamp push rod side is provided with a bevel, which is used to cooperate with the opening and closing of the clamp push rod.

5. A sodium-potassium collection device for continuous magnesium smelting according to claim 1, characterized in that, The sodium-potassium collection tube is made of high-temperature ceramic or high-temperature alloy; the inside of the sodium-potassium collection tube is coated with a high-temperature resistant coating of 0.3mm-0.5mm thickness.

6. A method for sodium and potassium collection in continuous magnesium smelting, comprising the sodium and potassium collection device for continuous magnesium smelting according to claim 1, characterized in that, Includes the following steps: Step 1. Select low-grade magnesium ore for smelting, reducing agent and flux, weigh them in a specific ratio, mix them and pelletize them to obtain pellets; Step 2. Place the prepared pellets into a vertical vacuum atmosphere furnace. The circulating pump supplies inert gas as a carrier gas to the vertical vacuum atmosphere furnace through the mixed gas outlet pipeline. After calcination in the carrier gas protection environment, the pellets enter the reduction stage. After adjusting the reaction temperature, reduction is carried out to obtain magnesium vapor. Step 3. Magnesium vapor enters the condenser for condensation, and metallic magnesium is collected. The K and Na vapors in the magnesium vapor enter the sodium-potassium collecting tube through the mixed gas inlet pipe. When the pressure sensor detects that the mass of K and Na has reached the set value, the tube-changing wheel is driven to rotate by motor I, and the sodium-potassium collecting tube enters the atmospheric pressure chamber II of the tube unloading device to remove the sodium-potassium collecting tube. At the same time, the tube-changing wheel is replenished with a new sodium-potassium collecting tube and driven into the vacuum chamber II of the tube-changing device for K and Na collection. Steps 1 to 2 are repeated to complete the collection of K and Na. When the pressure sensor detects that the K and Na masses have not reached the set values, repeat steps 1-2. After the pellets have burned 3-4 times, if the pressure sensor still detects that the K and Na masses have not reached the set values, the tube-changing wheel will rotate the sodium-potassium collecting tube into the atmospheric pressure chamber II of the tube-unloading device via motor I and remove it. The tube-changing wheel will then insert a new sodium-potassium collecting tube and drive it into the vacuum chamber II of the tube-changing device for a new round of K and Na collection. Repeat the above process to complete the collection of K and Na.

7. A method for sodium and potassium capture in continuous magnesium smelting according to claim 6, characterized in that, In step 1, the MgO content in the low-grade magnesium smelting ore is <30%, including but not limited to dolomite and magnesite; the reducing agent is ferrosilicon, aluminum shavings or carbon; and the flux is fluorite. When the reducing agent is ferrosilicon, the specific ratio by mass is dolomite:magnesite:ferrosilicon = 6.53:6.502:1.62; The flux is added at 3% of the total mass of the pellets; Pelletizing is carried out under pressure of 5MPa-20MPa; In step 2, the calcination temperature is 850℃-1050℃ and the calcination time is 60min-120min; in the reduction stage, the reduction temperature is 1150℃-1400℃ and the reduction time is 60min-120min. During the calcination and reduction stages, the type and flow rate of the carrier gas remain constant; the carrier gas flow rate is 0.05 m³ / h - 0.5 m³ / h.

8. A method for sodium and potassium capture in continuous magnesium smelting according to claim 6, characterized in that, The rotation speed of the tube-changing impeller is 0.2m / s-0.5m / s.

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