Equipment and method for preparing magnesium metal through CO vacuum directional reduction of dolomite

Abstract

The invention relates to the field of magnesium metal preparation, in particular to equipment and a method for preparing magnesium metal through CO vacuum directional reduction of dolomite, and solves the problems that in existing magnesium metal preparation, waste materials cannot be treated, and the cost is high. The device comprises a base, a calcination-CO preparation furnace, a calcination chamber, a reduction chamber, a CO preparation furnace, a condensation pipe, a discharging port, a sliding frame, an arc-shaped frame, a first driving assembly and an opening, arc-shaped rotating plates are symmetrically and rotationally connected to the two sides of the opening through spring hinges, and baffles located above the arc-shaped rotating plates are symmetrically connected to the inner walls of the front end and the rear end of the arc-shaped frame; a limiting plate abutting against the arc-shaped rotating plate is slidably connected to the lower side of the arc-shaped frame, a second driving assembly is further arranged on the calcination-CO preparation furnace, and the second driving assembly is used for driving the limiting plate to slide downwards and driving the arc-shaped rotating plate to turn downwards. According to the device and the method, the magnesium preparation cost can be reduced, various wastes generated in the preparation process are utilized, and the device and the method are more economical and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the field of magnesium metal preparation, and in particular to a device and a method for preparing magnesium metal by directional reduction of dolomite by CO vacuum. Background Art

[0002] Magnesium, known as the 'green metal of the 21st century,' is a core strategic resource for promoting low-carbon and lightweight manufacturing. The US government has included it in a list of 25 key strategic elements, and the European Union has designated it a "strategic" raw material through its Critical Raw Materials Directive. my country's magnesium industry boasts multiple competitive advantages: China boasts the world's largest magnesium reserves, with reserves of key minerals such as dolomite and magnesite among the highest globally (dolomite reserves account for 20% of the world's total, and magnesite reserves for 30%). China has ranked first in magnesium production for 25 consecutive years, reaching 950,000 tons in 2024, representing 95% of global magnesium production and the highest share among major non-ferrous metals. China has ranked first in magnesium consumption for 10 consecutive years and in magnesium exports for 12 consecutive years. Approximately 87% of the world's magnesium supply and 95% of Europe's magnesium consumption come from China.

[0003] Existing thermal reduction magnesium smelting processes all use magnesium-containing carbonate as raw material, which requires high-temperature calcination followed by reduction to produce metallic magnesium. The calcination process releases a large amount of CO2, which is not effectively utilized. The reduction reaction is mainly solid-solid or solid-liquid phase reaction, and the reducing agents used are mostly metals or metal compounds, which are expensive. In addition, there are kinetic limiting factors such as poor contact between particles at the reaction interface and the formation of a passivation layer. In the reduction process, CaO does not form an independent phase and cannot be effectively recovered.

[0004] In response to the existing thermal reduction magnesium smelting process, which suffers from direct high-temperature CO2 emissions and unutilized calcium resources, Patent No. CN202210832081.6 discloses a method for waste heat recovery and CO2 utilization in the combined production of ferrosilicon, magnesium, and semi-coke. The method converts high-temperature CO2 into methane, methanol, and carbon monoxide. However, it still suffers from the high price and high environmental impact of ferrosilicon, the limitations of solid-solid reaction kinetics, and the lack of CaO enrichment. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the present invention proposes an apparatus and method for preparing metallic magnesium by CO vacuum directional reduction of dolomite, which can avoid the use of relatively expensive reducing agents, reduce preparation costs, and also utilize the CO2 generated during the preparation process.

[0006] In order to solve the above technical problems, the basic technical solutions proposed by the present invention are: A device for preparing metallic magnesium by CO vacuum directional reduction of dolomite, comprising a base, a calcination-CO preparation furnace mounted on the base, a calcination chamber and a reduction chamber disposed on the upper and lower sides of the calcination-CO preparation furnace, a CO preparation furnace disposed on the rear side of the calcination-CO preparation furnace, the calcination chamber and the reduction chamber respectively communicating with the CO preparation furnace, a condenser tube also being connected on both sides of the reduction chamber, a plurality of discharge ports communicating with the calcination chamber or the reduction chamber being provided on the front surface of the calcination-CO preparation furnace, the discharge ports being arranged at equal intervals on the upper and lower sides, a slide corresponding to the discharge port being connected between the front and rear inner walls of the calcination chamber and the reduction chamber, and an arc-shaped frame being slidably connected to the slide; Driving components 1 are provided on both sides of the calcination-CO preparation furnace, and the driving component 1 is used to drive the various arc frames in the calcination chamber or the reduction chamber to slide out of the discharge port synchronously. An opening is provided at the bottom of the arc frame, and arc-shaped rotating plates are symmetrically connected on both sides of the opening through spring hinges. The inner walls at the front and rear ends of the arc frame are symmetrically connected to the baffle above the arc-shaped rotating plate, and the lower side of the arc frame is slidably connected to a limit plate that resists the arc-shaped rotating plate. The calcination-CO preparation furnace is also provided with a driving component 2, and the driving component 2 is used to drive the limit plate to slide down and the arc-shaped rotating plate to flip downward.

[0007] Preferably, the rear side of the calcining chamber is connected to a pipe 1, and the other end of the pipe 1 is connected to the CO preparation furnace, the rear side of the reduction chamber is connected to a pipe 2, and the other end of the pipe 2 is connected to the CO preparation furnace, a bracket is installed on the lower side of the CO preparation furnace, and a bin cover is provided on the rear side of the CO preparation furnace.

[0008] Preferably, the base is further provided with condensation chambers on both sides of the calcination-CO preparation furnace, and the condensation pipes are arranged in an S-shape and pass through the condensation chambers.

[0009] Preferably, the driving component 1 includes a connecting plate, a socket, a telescopic part 1, a T-shaped socket, and a telescopic part 2. The connecting plate is connected to each arc frame in the calcination chamber or the reduction chamber, the socket is connected to both sides of the connecting plate, the telescopic part 1 is installed on both sides of the calcination-CO preparation furnace, the T-shaped socket is connected to the output end of the telescopic part 1, the telescopic part 2 is connected on the upper and lower sides of each T-shaped socket, and the output end of the telescopic part 2 away from the T-shaped socket is connected to a card frame that cooperates with the card sleeve of the socket.

[0010] Preferably, the rear end of the arc frame is connected to a limiting slip ring, and the two sides of the limiting slip ring slide in contact with the slide, and the limiting slip ring is limited by the inner wall of the discharge port. The front end of the arc frame is connected to a warehouse door, and the warehouse door cooperates to cover the outer side of the discharge port, and the connecting plate is connected to each warehouse door.

[0011] Preferably, mounting seats are installed on both sides of the calcination-CO preparation furnace, and telescopic parts 1 are embedded on the upper and lower sides of the mounting seats.

[0012] Preferably, the second driving component includes a support frame, a guide rail, a guide seat, a telescopic part three, a hanging frame, and a top rod. The support frame is set in two and is connected to both sides of the upper end of the calcination-CO preparation furnace. The guide rail is installed on the support frame, and the guide seat is slidably set in the guide rail. The telescopic part three is installed on the guide seat, and the lower output end extends to the bottom of the guide rail, and is connected to a connecting frame at the extended end. The hanging frames are multiple and evenly spaced and connected to the connecting frame, and each hanging frame corresponds to the discharge port. The top rod is connected to the hanging frame and cooperates with the arc-shaped rotating plate and the limit plate.

[0013] Preferably, the front and rear ends of the limit plate are connected with a connecting seat, and the connecting seat is connected with a sliding rod that slides through the arc frame. A spring is connected between the upper end of the sliding rod and the arc frame and is sleeved on the outside of the sliding rod. The top rod is located between the baffle and the sliding rod, and the lower end of the hanging frame cooperates and contacts with the upper end of the sliding rod.

[0014] A method for preparing metallic magnesium by CO vacuum directional reduction of dolomite comprises the following steps: Step 1: Dolomite calcination to prepare CaO·MgO and CO2: Dolomite is selected as the raw material, crushed and ground, pressed into balls and sent into the arc frame in the calcination chamber for calcination to produce CaO·MgO. During calcination, CO2 is generated, and the CO2 is blown into the CO preparation furnace as a reaction component in the reduction process; Step 2: CO2 reacts with coking coal to produce CO by Bourdeau reaction: the coking coal is crushed and ground, and then reacted with the CO2 generated in step 1 under vacuum to produce CO, which is used as a reducing agent in the reduction process; Step 3: Preparation of metallic magnesium by vacuum reduction: The CO generated in step 2 is blown into the reduction chamber, and the CaO·MgO generated in step 1 is added to the arc frame in the reduction chamber for directional reduction to volatilize magnesium vapor, and CaO is enriched in the residue; Step 4: Condensing magnesium vapor to obtain condensed magnesium: The magnesium vapor generated in step 3 enters the condenser and condenses to obtain crystalline magnesium; Step 5: Material collection and sample analysis: Collect the condensate and residue and send them for sample analysis.

[0015] Preferably, the dolomite composition in step one is MgO 31.34wt%, CaO 21.94wt%, Fe 1.69wt%, Cu <0.005wt%, SiO20.38wt%, Al2O3 1.46wt%, and a burn rate of 43.18wt%. The molar ratio of the raw material dolomite to coking coal is greater than 2 to ensure that the CO2 generated by calcination is completely consumed. The ground particle size in step one and step two is less than 250 mesh. The ball pressing pressure in step one is 6-16 MPa to make the material into a block to prevent the spraying phenomenon during the vacuum process. The calcination temperature in step one is 1000-1300 K. The Boudor reaction pressure in step 2 is 10-100 Pa and the temperature is 700-900 K, so that CO2 and coking coal fully react to generate reducing CO. In the process of preparing metallic magnesium by vacuum reduction in step 3, the pressure is 10-100 Pa and the temperature is 2300-2500 K to ensure that the temperature reaches the reduction reaction. The condensation temperature in step 4 is 573-773 K to effectively condense the magnesium vapor and avoid the generation of magnesium powder.

[0016] The beneficial effects of the present invention are: 1. The technical solution of the present invention reduces the CO2 generated in the calcination chamber in the CO preparation furnace to obtain CO, and blows the CO into the reduction chamber to participate in the vacuum reduction process of preparing metallic magnesium, thereby improving the utilization rate of CO2 and reducing emissions. At the same time, it can also avoid the use of precious metals to participate in the reduction of metallic magnesium, thereby reducing costs. It can also enrich CaO in the residue, which is convenient for further processing or utilization of the residue; 2. The technical solution of the present invention is to set two upper and lower calcining chambers and a reduction chamber in the calcining-CO preparation furnace, so that the raw materials after pelletizing can be sent into the arc frame of the calcining chamber by a conveyor belt for calcination, and the CO2 generated by calcination is blown into the CO preparation furnace for reduction to produce CO. At the same time, the front sides of the arc frames in the calcining chamber and the reduction chamber are connected with warehouse doors, and the warehouse doors of each arc frame in the same calcining chamber or the reduction chamber are connected with a connecting plate and a clamping seat, which can be conveniently driven by the driving component to pull each arc frame in the calcining chamber to slide out from the discharge port, or each arc frame in the reduction chamber to slide out from the discharge port, or each arc frame in the calcining chamber and the reduction chamber to slide out from the discharge port synchronously; 3. The technical solution of the present invention can drive the arc rotating plates connected on both sides of the arc frame opening to rotate through the driving component 2, and then the raw materials after ball pressing contained between the baffles on both sides of the arc frame fall from the arc frame in the upper calcination chamber to the arc frame in the reduction chamber that slides out from the lower side, or act on the arc frame that slides out of the reduction chamber to dump out the residue after vacuum reduction of metallic magnesium on it, thereby improving the degree of automation and operational efficiency of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is a cross-sectional view of the side structure of the present invention; Figure 3 Schematic diagram of the relevant structures of the calcination-CO preparation furnace and the condensation chamber of the present invention; Figure 4 This is a schematic structural diagram of the CO production furnace of the present invention; Figure 5 This is a schematic diagram of the structure of the calcined-CO preparation furnace of the present invention; Figure 6 It is a structural schematic diagram of the arc frame and the slide of the present invention; Figure 7 It is a schematic diagram of the relevant structure on the arc frame of the present invention; Figure 8 It is a bottom view schematic diagram of the relevant structure on the arc frame of the present invention; Figure 9 A top view of the condensation chamber of the present invention; Figure 10 is a flow chart of the method of the present invention; Figure 11 The XRD pattern of the residue of the method of the present invention is shown in FIG. Figure 12 is the XRD pattern of the condensate of the method of the present invention; Figure 13 This is a SEM image of the condensate obtained by the method of the present invention.

[0018] Description of reference numerals: 1. Base; 2. Calcination-CO preparation furnace; 3. Calcination chamber; 4. Reduction chamber; 5. CO preparation furnace; 6. Pipeline 1; 7. Pipeline 2; 8. Bracket; 9. Bin cover; 10. Discharge port; 11. Slide; 12. Arc frame; 13. Opening; 14. Arc turn plate; 15. Limiting slip ring; 16. Bin door; 17. Baffle; 18. Slide rod; 19. Connecting seat; 20. Limiting plate; 21. Spring; 22. Condensation tube; 23. Condensation chamber; 24. Connecting plate; 25. Clamping seat; 26. Mounting seat; 27. Telescopic part 1; 28. T-shaped seat; 29. Telescopic part 2; 30. Clamping frame; 31. Support frame; 32. Guide rail; 33. Guide seat; 34. Telescopic part 3; 35. Connecting frame; 36. Hanging frame; 37. Top rod. DETAILED DESCRIPTION

[0019] The following will be combined with the Figure 1 To the attached Figure 10The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0020] Example 1: like Figure 1-10 As shown, the present invention discloses an apparatus for preparing metallic magnesium by CO vacuum directional reduction of dolomite, comprising a base 1, a calcination-CO preparation furnace 2 being mounted on the base 1, and a calcination chamber 3 and a reduction chamber 4 being provided on the upper and lower sides of the calcination-CO preparation furnace 2, a CO preparation furnace 5 being provided on the rear side of the calcination-CO preparation furnace 2, the calcination chamber 3 and the reduction chamber 4 being respectively connected to the CO preparation furnace 5, a condenser 22 being further connected to both sides of the reduction chamber 4, a plurality of discharge ports 10 being provided on the front surface of the calcination-CO preparation furnace 2, which are connected to the calcination chamber 3 or the reduction chamber 4, and the discharge ports 10 on the upper and lower sides being correspondingly arranged at equal intervals, a slide 11 corresponding to the discharge port 10 being connected between the front and rear inner walls of the calcination chamber 3 and the reduction chamber 4, and an arc-shaped frame 12 being slidably connected to the slide 11; Among them, the heating method in the calcination chamber 3 and the reduction chamber 4 of the calcination-CO preparation furnace 2 adopts the existing electromagnetic or dye heating; A driving component 1 is provided on both sides of the calcination-CO preparation furnace 2. The driving component 1 is used to drive the various arc frames 12 in the calcination chamber 3 or the reduction chamber 4 to slide out of the discharge port 10 synchronously. An opening 13 is provided at the bottom of the arc frame 12. The two sides of the opening 13 are symmetrically connected with an arc-shaped rotating plate 14 through a spring hinge. The inner walls of the front and rear ends of the arc frame 12 are symmetrically connected to the baffle 17 above the arc-shaped rotating plate 14. The lower side of the arc frame 12 is slidably connected to a limit plate 20 that resists the arc-shaped rotating plate 14. A driving component 2 is also provided on the calcination-CO preparation furnace 2. The driving component 2 is used to drive the limit plate 20 to slide down and the arc-shaped rotating plate 14 to flip downward.

[0021] The rear side of the calcining chamber 3 is connected to a pipe 6, and the other end of the pipe 6 is connected to the CO preparation furnace 5. The rear side of the reduction chamber 4 is connected to a pipe 2 7, and the other end of the pipe 2 7 is connected to the CO preparation furnace 5. A bracket 8 is installed on the lower side of the CO preparation furnace 5. The rear side of the CO preparation furnace 5 is provided with a bin cover 9, which is convenient for the CO2 produced by calcination in the calcining chamber 3 to be blown into the CO preparation furnace 5 through the pipe 1 6. At the same time, the CO produced by reduction in the CO preparation furnace 5 can also be blown into the reduction chamber through the pipe 2 7 to participate in the process of vacuum reduction to prepare metallic magnesium. The setting of the bin cover 9 makes it convenient to open the CO preparation furnace 5 and add crushed and ground coke therein.

[0022] The base 1 is further provided with condensation chambers 23 on both sides of the calcination-CO preparation furnace 2 . The condensation pipes 22 are arranged in an S-shape and pass through the condensation chambers 23 . The condensation chambers 23 are filled with cooling oil or other condensation media.

[0023] Example 2: like Figure 1-10 As shown, the present invention discloses an apparatus for preparing metallic magnesium by CO vacuum directional reduction of dolomite. Compared with the first embodiment, the present embodiment discloses the structure of the driving component one.

[0024] The driving component 1 includes a connecting plate 24, a base 25, a telescopic part 1 27, a T-shaped base 28, and a telescopic part 2 29. The connecting plate 24 is connected to each arc frame 12 in the calcination chamber 3 or the reduction chamber 4. The base 25 is connected to both sides of the connecting plate 24. The telescopic part 1 27 is installed on both sides of the calcination-CO preparation furnace 2. The T-shaped base 28 is connected to the output end of the telescopic part 1 27. The telescopic part 2 29 is connected on the upper and lower sides of each T-shaped base 28. The output end of the telescopic part 29 away from the T-shaped base 28 is connected to a card frame 30 that cooperates with the card sleeve of the base 25.

[0025] In this way, by controlling the telescopic parts 29 on the upper and lower sides of the T-shaped seat 28 to operate independently or synchronously, the upper card frame 30 and the upper card seat 25 can be driven to engage the card sleeve, and the lower card frame 30 and the lower card seat 25 can be driven to engage the card sleeve.

[0026] Specifically, when the upper clamping frame 30 is clamped with the upper clamping seat 25, the extension of the telescopic member 27 can push each arc frame 12 in the calcining chamber 3 to slide out of the discharge port 10 synchronously; When the lower card frame 30 is inserted into the lower card seat 25, the extension of the telescopic member 27 can push the arc frames 12 in the reduction chamber 4 to slide out of the discharge port 10 synchronously. When the upper clamping frame 30 is clamped with the upper clamping seat 25, and the lower clamping frame 30 is also clamped with the lower clamping seat 25, the telescopic member 27 can be extended to synchronously push the various arc frames 12 in the calcining chamber 3 and the various arc frames 12 in the reduction chamber 4 to slide out of the discharge port 10 synchronously.

[0027] The rear end of the arc frame 12 is connected to a limiting slip ring 15, and both sides of the limiting slip ring 15 slide in contact with the slide 11, and the limiting slip ring 15 is limited by the inner wall of the discharge port 10. The front end of the arc frame 12 is connected to a warehouse door 16, and the warehouse door 16 is fitted to cover the outer side of the discharge port 10, and the connecting plate 24 is connected to each warehouse door 16. In this way, the limiting slip ring 15 is limited by the inner wall of the discharge port 10, and the arc frame 12 will not slide out of the discharge port 10. At the same time, the sliding of the limiting slip ring 15 and the slide 11 can also ensure the stability of the arc frame 12 when sliding, and the setting of the warehouse door 16 facilitates the sealing of the discharge port 10.

[0028] Mounting seats 26 are installed on both sides of the calcination-CO preparation furnace 2, and telescopic parts 27 are embedded on the upper and lower sides of the mounting seats 26.

[0029] Example 3: like Figure 1-10 As shown, the present invention discloses an apparatus for preparing metallic magnesium by CO vacuum directional reduction of dolomite. Compared with the second embodiment, this embodiment discloses the structure of the second driving component.

[0030] Drive component two includes a support frame 31, a guide rail 32, a guide seat 33, a telescopic part three 34, a hanging frame 36, and a top rod 37. The support frame 31 is set in two and is connected to both sides of the upper end of the calcination-CO preparation furnace 2. The guide rail 32 is installed on the support frame 31, and the guide seat 33 is slidably set in the guide rail 32. The telescopic part three 34 is installed on the guide seat 33, and the lower output end extends to the bottom of the guide rail 32, and is connected to a connecting frame 35 at the extended end. The hanging frames 36 are multiple and evenly spaced and connected to the connecting frame 35, and each hanging frame 36 corresponds to the discharge port 10. The top rod 37 is connected to the hanging frame 36 and cooperates with the arc-shaped rotating plate 14 and the limit plate 20.

[0031] The position of the guide seat 33 can be controlled by the guide rail 32, so that when the arc-shaped frame 12 in the calcining chamber 3 slides out from the discharge port 10 and the pelletized raw materials are added thereto through the conveyor belt, the guide seat 33 can be controlled to slide above the calcining-CO preparation furnace 2 to avoid it; After the calcination in the calcination chamber 3 is completed, when the raw materials in the arc frame 12 in the calcination chamber 3 need to be transferred to the arc frame 12 in the reduction chamber 4, the driving component 1 is used to drive the arc frames 12 in the calcination chamber 3 and the reduction chamber 4 to slide out from their respective discharge ports 10, and then the position of the guide seat 33 is adjusted so that each push rod 37 moves to the top of the arc-shaped rotating plate 14 and is located on the side where the baffles 17 on both sides are away from each other. Then, the telescopic member 34 is extended to drive the push rod 37 to move downward, overcome the force of the spring hinge, and drive the arc-shaped rotating plates 14 on both sides to flip downward, so that the calcined raw materials can be poured into the arc frame 12 in the lower reduction chamber 4; When the raw materials in the reduction chamber 4 have completed the production of magnesium, the driving component 1 controls only the arc frame 12 in the lower reduction chamber 4 to slide out from the discharge port 10, and then controls the push rod 37 to perform the same operation, so that the residue in the corresponding arc frame 12 can be dumped to facilitate the subsequent vacuum reduction to prepare metallic magnesium.

[0032] The front and rear ends of the limit plate 20 are connected with a connecting seat 19, and the connecting seat 19 is connected to a slide bar 18 that slides through the arc frame 12. A spring 21 is connected between the upper end of the slide bar 18 and the arc frame 12, and the top rod 37 is between the baffle 17 and the slide bar 18. The lower end of the hanging frame 36 cooperates with the upper end of the slide bar 18. This arrangement makes it possible for the spring 21 to drive the limit plate 20 to move up and conflict with the arc rotating plate 14 when there is no external force. Under the elastic force of the spring hinge on the plate 14, the arc-shaped rotating plates 14 on both sides can be stably close to each other and will not flip open due to the gravity of the raw materials contained therein. At the same time, when the push rod 37 moves downward, the hanging frame 36 will first act on the arc-shaped rotating plate 14 with the push rod 37, and push the sliding rod 18, so that before the push rod 37 pushes the arc-shaped rotating plate 14 to rotate, the limit plate 20 has been resisted by the hanging frame 36 and moved downward at one end, ensuring that the arc-shaped rotating plate 14 can be smoothly pushed open by the push rod 37.

[0033] Example 4: like Figure 1-13 As shown, the present invention discloses a method for preparing metallic magnesium by CO vacuum directional reduction of dolomite, comprising the following steps: Step 1: Calcination of dolomite to prepare CaO·MgO and CO2: Dolomite is selected as raw material, crushed and ground, pressed into balls, and then sent to the arc frame 12 in the calcination chamber 3 for calcination to produce CaO·MgO. CO2 is generated during calcination and blown into the CO preparation furnace 5 as a reaction component in the reduction process; Step 2: CO2 reacts with coking coal to produce CO by Bourdeau reaction: the coking coal is crushed and ground, and then reacted with the CO2 generated in step 1 under vacuum to produce CO, which is used as a reducing agent in the reduction process; Step 3: Preparation of metallic magnesium by vacuum reduction: The CO generated in step 2 is blown into the reduction chamber 4, and the CaO·MgO generated in step 1 is added to the arc frame 12 in the reduction chamber 4 for directional reduction to volatilize magnesium vapor, and CaO is enriched in the residue; Step 4: Condensing magnesium vapor to obtain condensed magnesium: The magnesium vapor generated in step 3 enters the condenser 22 and condenses to obtain crystalline magnesium; Step 5: Material collection and sample analysis: Collect the condensate and residue and send them for sample analysis.

[0034] The dolomite composition in step 1 is MgO 31.34wt%, CaO 21.94wt%, Fe 1.69wt%, Cu <0.005wt%, SiO2 0.38wt%, Al2O3 1.46wt%, and a burn rate of 43.18wt%. The molar ratio of the raw material dolomite to coking coal is greater than 2 to ensure that the CO2 generated by calcination is completely consumed. The grinding particle size in steps 1 and 2 is less than 250 mesh. The ball pressing pressure in step 1 is 6-16 MPa to make the material into blocks to prevent the occurrence of material spraying during the vacuum process. The calcination temperature in step 1 is 1000-1300 K. In step 2, the Boudor reaction pressure is 10-100 Pa and the temperature is 700-900 K, so that CO2 and coking coal fully react to generate reducing CO. In step 3, during the vacuum reduction process to prepare metallic magnesium, the pressure is 10-100 Pa and the temperature is 2300-2500 K to ensure that the temperature reaches the reduction reaction. In step 4, the condensation temperature is 573-773 K to effectively condense the magnesium vapor and avoid the generation of magnesium powder.

[0035] Embodiment 5: like Figure 10-13 As shown, the present invention discloses a method for preparing metallic magnesium by directional reduction of dolomite by CO vacuum: Dolomite was crushed and ground to a size of less than 250 mesh and then die-cast into blocks at a pressure of 6-16 MPa. A vacuum furnace was flushed with inert argon, and the blocks were placed in the furnace. The temperature was raised at a controlled rate of 10 K / min, and calcined for one hour at a temperature of 1000-1300 K to produce CaO·MgO and CO2. Coke was crushed and ground to a size of less than 250 mesh and placed in a second reactor. The pressure in the furnace was controlled at 10-100 Pa and the temperature was raised at a rate of 10 K / min. When the temperature reached 700-900 K, high-temperature CO2 was introduced to produce CO. The generated CO was introduced into the first reactor, where it reacted with CaO·MgO to produce metallic magnesium. The pressure was controlled at 10-100 Pa and the temperature was raised at a rate of 10 K / min. When the temperature reached 2300-2500 K, the temperature was maintained for one hour. The reduction rate reached 72.38%, and the purity of the crystalline magnesium was 92.56%.

[0036] Example 6: like Figure 10-13 As shown, the present invention discloses a method for preparing metallic magnesium by directional reduction of dolomite by CO vacuum: Dolomite was crushed and ground to a size of less than 250 mesh and then die-cast into blocks at a pressure of 6-16 MPa. A vacuum furnace was flushed with inert argon, and the blocks were placed in the furnace. The temperature was raised at a controlled rate of 10 K / min, and calcined for 2 hours at a temperature of 1000-1300 K to produce CaO·MgO and CO2. Coke was crushed and ground to a size of less than 250 mesh and placed in a second reactor. The pressure in the furnace was controlled at 10-100 Pa and the temperature was raised at a rate of 10 K / min. When the temperature reached 700-900 K, high-temperature CO2 was introduced to produce CO. The generated CO was introduced into the first reactor, where it reacted with CaO·MgO to produce metallic magnesium. The pressure was controlled at 10-100 Pa and the temperature was raised at a rate of 10 K / min. When the temperature reached 2300-2500 K, the temperature was maintained for 1.5 hours. The reduction rate reached 80.64%, and the purity of the crystalline magnesium was 92.59%. Compared with the fifth embodiment, it can be concluded that as the Boudol reaction time increases, the amount of CO generated increases, and its reducing effect on CaO·MgO increases.

[0037] Embodiment seven: like Figure 10-13 As shown, the present invention discloses a method for preparing metallic magnesium by directional reduction of dolomite by CO vacuum: Dolomite was crushed and ground to a size of less than 250 mesh and then die-cast into blocks at a pressure of 6-16 MPa. A vacuum furnace was flushed with inert argon, and the blocks were placed in the furnace. The temperature was raised at a controlled rate of 10 K / min, and calcined for two hours at a temperature of 1000-1300 K to produce CaO·MgO and CO2. Coke was crushed and ground to a size of less than 250 mesh and placed in a second reactor. The pressure in the furnace was controlled at 10-100 Pa and the temperature was raised at a rate of 10 K / min. When the temperature reached 700-900 K, high-temperature CO2 was introduced to produce CO. The generated CO was introduced into the first reactor, where it reacted with CaO·MgO to produce metallic magnesium. The pressure was controlled at 10-100 Pa and the temperature was raised at a rate of 10 K / min. When the temperature reached 2300-2500 K, the temperature was maintained for two hours. The reduction rate reached 80.64%, and the purity of the crystalline magnesium was 94.14%. Compared with Example 6, it can be concluded that as the reduction reaction time increases, the interaction between CO and CaO·MgO in the system increases. At the same time, the extension of the time allows the magnesium vapor to be fully condensed, thereby improving the purity of the crystalline magnesium.

[0038] The residue and condensate in Example 7 were subjected to XRD and SEM detection, and the detection results were as follows: Figures 11 to 13 shown.

[0039] Based on the disclosure and teachings of the above description, those skilled in the art may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and modifications and variations of the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A device for preparing metallic magnesium by CO vacuum directional reduction of dolomite, comprising a base (1), a calcination-CO preparation furnace (2) being mounted on the base (1), a calcination chamber (3) and a reduction chamber (4) being arranged on upper and lower sides of the calcination-CO preparation furnace (2), a CO preparation furnace (5) being arranged on the rear side of the calcination-CO preparation furnace (2), the calcination chamber (3) and the reduction chamber (4) being respectively connected to the CO preparation furnace (5), and condensation pipes (22) being further connected on both sides of the reduction chamber (4), characterized in that: The front surface of the calcination-CO preparation furnace (2) is provided with a plurality of discharge ports (10) that are in communication with the calcination chamber (3) or the reduction chamber (4), and the discharge ports (10) on the upper and lower sides are arranged at equal intervals. Slides (11) corresponding to the discharge ports (10) are connected between the front and rear inner walls of the calcination chamber (3) and the reduction chamber (4), and an arc-shaped frame (12) is slidably connected to the slides (11); The calcination-CO preparation furnace (2) is provided with a driving component 1 on both sides, and the driving component 1 is used to drive each arc frame (12) in the calcination chamber (3) or the reduction chamber (4) to slide out from the discharge port (10) synchronously. An opening (13) is provided at the bottom of the arc frame (12), and arc rotating plates (14) are symmetrically connected on both sides of the opening (13) through spring hinges. The inner walls of the front and rear ends of the arc frame (12) are symmetrically connected to a baffle (17) located above the arc rotating plate (14). The lower side of the arc frame (12) is slidably connected to a limit plate (20) that resists the arc rotating plate (14). The calcination-CO preparation furnace (2) is also provided with a driving component 2, and the driving component 2 is used to drive the limit plate (20) to slide down and the arc rotating plate (14) to flip downward.

2. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 1, characterized in that: The rear side of the calcining chamber (3) is connected to a pipe 1 (6), and the other end of the pipe 1 (6) is connected to the CO preparation furnace (5). The rear side of the reduction chamber (4) is connected to a pipe 2 (7), and the other end of the pipe 2 (7) is connected to the CO preparation furnace (5). A bracket (8) is installed on the lower side of the CO preparation furnace (5), and a bin cover (9) is provided on the rear side of the CO preparation furnace (5).

3. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 1, characterized in that: The base (1) is further provided with condensation chambers (23) on both sides of the calcination-CO preparation furnace (2), and the condensation pipe (22) is wound and passed through the condensation chamber (23) in an S-shape.

4. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 1, characterized in that: The driving assembly 1 includes a connecting plate (24), a clamping seat (25), a telescopic member 1 (27), a T-shaped seat (28), and a telescopic member 2 (29). The connecting plate (24) is connected to each arc frame (12) in the calcining chamber (3) or the reduction chamber (4). The clamping seat (25) is connected to both sides of the connecting plate (24). The telescopic member 1 (27) is installed on both sides of the calcining-CO preparation furnace (2). The T-shaped seat (28) is connected to the output end of the telescopic member 1 (27). The telescopic member 2 (29) is connected to both upper and lower sides of each T-shaped seat (28). The output end of the telescopic member 2 (29) away from the T-shaped seat (28) is connected to a clamping frame (30) that cooperates with the clamping sleeve of the clamping seat (25).

5. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 4, characterized in that: The rear end of the arc frame (12) is connected to a limiting slip ring (15), and both sides of the limiting slip ring (15) slide in contact with the slide (11), and the limiting slip ring (15) is limited by the inner wall of the discharge port (10). The front end of the arc frame (12) is connected to a bin door (16), and the bin door (16) is fitted and covered with the outer side of the discharge port (10). The connecting plate (24) is connected to each bin door (16).

6. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 4, characterized in that: Mounting seats (26) are installed on both sides of the calcination-CO preparation furnace (2), and telescopic parts (27) are embedded on the upper and lower sides of the mounting seats (26).

7. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 1, characterized in that: The driving component 2 includes a support frame (31), a guide rail (32), a guide seat (33), a telescopic member 3 (34), a hanging frame (36), and a top rod (37). The support frame (31) is provided in two pieces and is connected to both sides of the upper end of the calcination-CO preparation furnace (2). The guide rail (32) is installed on the support frame (31). The guide seat (33) is slidably set in the guide rail (32). The telescopic member 3 (34) is installed on the guide seat (33), and the lower output end extends to the bottom of the guide rail (32), and is connected to a connecting frame (35) at the extended end. The hanging frames (36) are connected to the connecting frame (35) in multiple equal intervals, and each hanging frame (36) corresponds to the discharge port (10). The top rod (37) is connected to the hanging frame (36) and cooperates with the arc-shaped rotating plate (14) and the limit plate (20).

8. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 7, characterized in that: The front and rear ends of the limit plate (20) are connected to a connecting seat (19), and the connecting seat (19) is connected to a slide bar (18) that slides through the arc frame (12). A spring (21) that is sleeved on the outside of the slide bar (18) is connected between the upper end of the slide bar (18) and the arc frame (12). The top rod (37) is located between the baffle (17) and the slide bar (18), and the lower end of the hanging frame (36) is in contact with the upper end of the slide bar (18).

9. A method for preparing metallic magnesium by CO vacuum directional reduction of dolomite, comprising the apparatus for preparing metallic magnesium by CO vacuum directional reduction of dolomite according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Calcination of dolomite to prepare CaO·MgO and CO2: Dolomite is selected as raw material, crushed and ground, pressed into balls and then sent to the arc frame (12) in the calcination chamber (3) for calcination to produce CaO·MgO. CO2 is generated during calcination and blown into the CO preparation furnace (5) as a reaction component in the reduction process; Step 2: CO2 reacts with coking coal to produce CO by Bourdeau reaction: the coking coal is crushed and ground, and then reacted with the CO2 generated in step 1 under vacuum to produce CO, which is used as a reducing agent in the reduction process; Step 3: Preparation of metallic magnesium by vacuum reduction: Blow the CO generated in step 2 into the reduction chamber (4), add the CaO·MgO generated in step 1 into the arc frame (12) in the reduction chamber (4), perform directional reduction to volatilize magnesium vapor, and enrich CaO in the residue; Step 4: Condensing magnesium vapor to obtain condensed magnesium: The magnesium vapor generated in step 3 enters the condenser (22) and condenses to obtain crystalline magnesium; Step 5: Material collection and sample analysis: Collect the condensate and residue and send them for sample analysis.

10. The device for preparing magnesium metal by CO vacuum directional reduction of dolomite according to claim 9, characterized in that: The dolomite composition in step 1 is MgO 31.34wt%, CaO 21.94wt%, Fe 1.69wt%, Cu <0.005wt%, SiO2 0.38wt%, Al2O3 1.46wt%, and a burn rate of 43.18wt%. The molar ratio of the raw material dolomite to coking coal is greater than 2. The ground particle size in steps 1 and 2 is less than 250 mesh. The ball pressing pressure in step 1 is 6-16 MPa. The calcination temperature in step 1 is 1000-1300 K. The Boudor reaction pressure in step 2 is 10-100 Pa and the temperature is 700-900 K. In the process of preparing metallic magnesium by vacuum reduction in step 3, the pressure is 10-100 Pa and the temperature is 2300-2500 K. The condensation temperature in step 4 is 573-773 K.

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