Internal heating method vacuum magnesium smelting device and method

Abstract

The invention discloses an internal heating method vacuum magnesium smelting device and method, and belongs to the technical field of non-ferrous metal smelting. Comprising a vacuum electric heating horizontal reduction furnace, a trolley mechanism for conveying square materials into and out of the horizontal reduction furnace, and a crystallization chamber connected to one side of the horizontal reduction furnace. A reduction chamber is arranged on a plane steel plate in the horizontal reduction furnace, a plurality of electric heating elements are arranged on the surfaces of the inner walls of the two sides of the reduction chamber, a plurality of layers of material trays on the trolley mechanism are used for loading square materials, and the crystallization chamber is composed of a main pipeline and a plurality of crystallizers connected to the two sides of the main pipeline. The trolley mechanism loaded with the square materials enters the horizontal reduction furnace and can be combined with the reduction chamber to form a closed space, the square materials are subjected to reduction reaction in the closed space to continuously generate magnesium steam, and the magnesium steam is captured by the crystallizer and condensed into solid metal magnesium. Compared with the existing Pidgeon process magnesium smelting technology, the method has the advantages of energy conservation, environmental protection, high production efficiency, flexible equipment design and low equipment manufacturing cost.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal smelting, and in particular to an internal heating method vacuum magnesium smelting device and method. Background Art

[0002] Metal magnesium and magnesium alloys are the lightest metal structural materials with the advantages of high specific strength and specific stiffness, good damping and vibration reduction, high thermal conductivity and electrical conductivity, strong electromagnetic shielding, easy cutting and recycling. They are known as the "green engineering materials of the 21st century" and are widely used in transportation, electronic products, building materials, aerospace and other fields.

[0003] Magnesium metal smelting methods can be divided into two categories: electrolysis and thermal reduction. The electrolysis method uses magnesium chloride as raw material. When electrolysis is used to obtain magnesium metal, chlorine gas is produced as a by-product, which is difficult to solve environmental problems. Currently, less than 20% of the global magnesium metal production is produced by electrolysis.

[0004] The main process of thermal reduction is silicon thermal reduction, which is to use silicon as a reducing agent to reduce magnesium oxide, obtain magnesium metal vapor under high temperature and vacuum conditions, and then condense it to obtain magnesium metal. Among them, the mainstream of silicon thermal reduction is the Pijiang method.

[0005] The essence of the Pijiang process is to use ferrosilicon (75% Si) to reduce and calcine dolomite (calcined white) to refine magnesium under 1200℃ and high vacuum (<5Kpa) conditions by externally heating the reduction tank (reducing metal magnesium container). Because of its advantages of short process flow, simple equipment, flexible production scale, and high purity of finished magnesium, coupled with my country's rich magnesium ore dolomite resources and solid fuel coal resources, it has been promoted and applied in my country. Although the energy consumption and pollution of the Pijiang process have been reduced to a certain extent through continuous improvements, there are still some problems that are difficult to overcome:

[0006] 1. External heating is adopted, and the heat is gradually transferred from the outside of the reduction tank to the inside, and the thermal energy utilization rate is low.

[0007] 2. In the process of reducing magnesium metal, in order to prevent the reduction tank from deformation (deflation) and cracking due to high-temperature oxidation and high-temperature creep, the reduction tank needs to have high resistance to high-temperature oxidation and high-temperature strength. Therefore, the reduction tank is made of high-cost heat-resistant steel containing nickel, chromium and other elements. Even so, the service life of the reduction tank is still short, with an average life of 3-4 months.

[0008] 3. As the volume of the reduction tank increases, the weight and surface area of ​​the reduction tank increase accordingly, the ability of the reduction tank to resist high temperature creep decreases, and the service life is further shortened. Due to the limited volume of the reduction tank, the amount of raw materials loaded is not large / the output of magnesium metal is not high: currently the maximum loading capacity of a single container is 600 kg, and a single reduction tank produces 90-100 kg of raw magnesium in 18 hours. Therefore, the Pijiang process magnesium smelting plant occupies a large area, the on-site management is difficult, and it is not easy to achieve large-scale production and mechanized operation.

[0009] 4. During the reduction process of magnesium metal, the raw materials come into contact with the reduction tank and undergo a chemical reaction, and the products adhere to the inner wall of the reduction tank, which is the phenomenon of "sticking to the tank and glazing" common in the Pidgeon method. On the one hand, the glaze increases the thermal resistance of the reduction tank, further reducing the utilization rate of thermal energy; on the other hand, it occupies the internal space of the reduction tank, further reducing the raw material loading amount / magnesium production. In order to slow down the phenomenon of "sticking to the tank and glazing" on the inner wall of the reduction tank, it is necessary to regularly remove the bonded glaze by manual "poking" or "scraping", which is labor-intensive and poses a risk of scalding and burns to employees.

[0010] The Bolzano process developed in Italy belongs to the internal heat reduction method, which is an improved process of the Pidgeon process. The raw materials used are the same as those of the Pidgeon process, but the heating method is changed from external heating to internal heating. An internally heated brick columnar horizontal reduction furnace is used, and the block material pressed after mixing calcined dolomite and ferrosilicon is placed on a support frame in the horizontal reduction furnace, and the material is heated by the conductive support frame. A crystallization chamber for collecting gaseous metal magnesium products is provided at the top of the horizontal reduction furnace. The Bolzano process improves the utilization rate of thermal energy because it adopts internal heating, and uses a brick body instead of an expensive heat-resistant alloy steel reduction chamber to reduce the equipment cost. However, the Bolzano process still has the problem that the material is bonded during the reduction process, which makes it inconvenient to remove. Chinese patent CN1952191A discloses "an internal resistance heating metal thermal reduction magnesium smelting furnace and magnesium smelting method", the main change of which is to add a receiving chamber for reducing slag at the bottom of the horizontal reduction furnace, which is conducive to automatically removing the reducing slag in the horizontal reduction furnace, but does not solve the problem of the material bonding to the heating body during the reduction process, which makes it inconvenient to clean the slag. Chinese patent CN102816938A discloses "horizontal reduction furnace for magnesium smelting by electric heating method", and its main change is that the material in the furnace can be realized without contacting with the heating element, so that the problem of material adhesion to the heating element can be avoided, but the disadvantage is that the crystallization chamber is not arranged in the top area with lower temperature in the horizontal reduction furnace, but is arranged in the two side areas with higher temperature in the furnace, so there is magnesium vapor that is more likely to condense on the top of the horizontal reduction furnace rather than in the crystallization chamber, resulting in a lower yield of metallic magnesium. Chinese patent CN00124698.4 discloses "internal heat method magnesium smelting production process and equipment", which uses gas as fuel, and heats the pellets made of magnesium oxide and ferrosilicon to reduce and produce metallic magnesium by arranging the radiation tube connected with the combustion chamber in the reactor. Its main change is to use gas energy instead of electric energy, but it is impossible to solve the deformation of the tank body caused by creep under the high temperature and high vacuum conditions of the reactor, and the "sticky tank glaze" phenomenon that the reaction product adheres to the inner wall of the reactor and the radiation tube wall. Summary of the invention

[0011] The purpose of the present invention is to provide an internal heating method vacuum magnesium smelting device and method, aiming to solve at least one of the technical problems existing in the above-mentioned prior art. To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows:

[0012] An internal heating method vacuum magnesium smelting device, comprising:

[0013] A horizontal reduction furnace, wherein an openable and closable arched furnace door is provided at the left end of the horizontal reduction furnace, a detachable arched sealing cover is provided at the right end of the horizontal reduction furnace, a reduction chamber and a trolley track are fixedly provided on a flat steel plate fixedly provided on the bottom of the inner cavity of the horizontal reduction furnace, the trolley track is located in the reduction chamber, the reduction chamber is made of refractory bricks, and the cross-sectional shape perpendicular to the axis direction of the horizontal reduction furnace is in a ∏ shape, the side of the reduction chamber close to the arched furnace door is open, and the side of the reduction chamber close to the arched sealing cover is closed, a heat-resistant steel pipe extending into the reduction chamber is plugged into the center of the arched sealing cover, the inner wall of the heat-resistant steel pipe is fitted with a refractory lining, and a plurality of electric heating elements are arranged on the inner wall surfaces on both sides of the reduction chamber;

[0014] The trolley mechanism includes a bottom plate, a traction track and a traction device are arranged on the top of the bottom plate, a lifting device for driving the bottom plate to rise and fall is arranged at the bottom of the bottom plate, the trolley mechanism also includes a heat-resistant base plate, a plurality of rollers are installed at the bottom of the heat-resistant base plate, a plurality of material trays are arranged at intervals on the top of the heat-resistant base plate, a vertical side plate is arranged at one end of the heat-resistant base plate, and a heat-insulating layer is arranged on the side of the side plate close to the traction track;

[0015] The crystallization chamber includes a main pipeline and a number of crystallizers connected to both sides of the main pipeline. The left end of the main pipeline is connected to the heat-resistant steel pipe, and the right end of the main pipeline is connected to the vacuum, dust removal and air intake equipment outside the horizontal reduction furnace.

[0016] As a further solution of the present invention: the space between the inner wall of the horizontal reduction furnace and the outer wall of the reduction chamber is filled with thermal insulation cotton.

[0017] As a further solution of the present invention: the vertical distance between the flat steel plate and the central axis of the horizontal reduction furnace is 0.6-0.8 times the inner radius of the horizontal reduction furnace.

[0018] As a further solution of the present invention: a left flange is provided on the outer peripheral fixed sleeve at the left end of the horizontal reduction furnace, a left sealing ring is provided on the side of the left flange close to the arch furnace door, a furnace door flange is provided on the edge fixed sleeve of the arch furnace door, and the furnace door flange matches the left flange;

[0019] A right flange is arranged on the outer peripheral fixed sleeve at the right end of the horizontal reduction furnace, a right sealing ring is arranged on the side of the right flange close to the arched sealing cover, a sealing cover flange is arranged on the edge fixed sleeve of the arched sealing cover, and the sealing cover flange matches the right flange.

[0020] As a further solution of the present invention: the heat-resistant substrate includes a bottom heat-resistant steel plate, a middle fire-resistant layer and a plurality of upper heat-resistant steel plates arranged in sequence from bottom to top.

[0021] As a further solution of the present invention: a heat-insulating layer is provided on one side of the side plate close to the traction track.

[0022] As a further solution of the present invention: the crystallizer includes a cooling chamber and a crystallization barrel, one end of the cooling chamber is connected to the inside of the main pipeline, and the open end of the crystallization barrel is detachably sealed and plugged into one end of the cooling chamber away from the main pipeline.

[0023] And, an internal heating method vacuum magnesium smelting method, comprising:

[0024] S1, making the raw materials into honeycomb block materials;

[0025] S2, the cube materials are evenly placed on the material trays, and the loaded material trays are stacked on the heat-resistant base plate of the trolley mechanism in sequence, leaving gaps between the material trays for magnesium vapor to escape;

[0026] S3, the arched furnace door is opened, and the lifting device drives the bottom plate to rise until the traction track is flush with the trolley track in the horizontal reduction furnace. The heat-resistant substrate stacked with material trays is driven into the reduction chamber by the traction device. After a closed space is formed in the reduction chamber, the arched furnace door is closed;

[0027] S4, the air pressure inside the reduction chamber is pumped down to less than 10 Pa through external equipment, and the circulating cooling water of the crystallizer is connected, and the power supply of the resistance heating element inside the reduction chamber is turned on. The temperature inside the reduction chamber reaches 1200°C, and the block material begins to undergo a reduction reaction and continuously produces magnesium vapor, which is captured by the crystallizer and condensed into solid metal magnesium;

[0028] S5, when the material reduction reaction is finished and the internal and external pressures of the horizontal reduction furnace are balanced, the crystallizer can be taken out to obtain solid magnesium metal, the arched furnace door is opened, the heat-resistant substrate stacked with the material tray is withdrawn outside the horizontal reduction furnace, and the arched furnace door is closed;

[0029] S6, removing the material tray containing the magnesium reduction slag on the trolley mechanism, and then repeating steps S1-S5 to enter a new round of magnesium reduction process.

[0030] As a further solution of the present invention: the raw materials in step S1 include calcined dolomite, ferrosilicon and fluorite.

[0031] As a further solution of the present invention: in step S1, the gap between adjacent material trays is 50 mm.

[0032] The present invention has the following beneficial effects:

[0033] The present invention provides a reduction chamber made of refractory bricks in the reduction furnace, and the trolley mechanism and the reduction chamber cooperate to form a vacuum enclosed space. The reduction reaction is carried out in the enclosed space, so that the shell of the horizontal reduction furnace is in a room temperature environment for a long time. Even if a relatively cheap shell welded with steel plates for boilers and pressure vessels is used, it can meet the long-term use requirements, thereby overcoming the shortcomings of the high cost and short life of the Pidgeon reduction tank; at the same time, it also overcomes the problem of low single tank output due to the limited volume of the Pidgeon reduction tank; in the embodiment provided by the present invention, about 500 kilograms of magnesium metal can be produced at a time, which is about 5 times higher than that of the current Pidgeon process, and the single magnesium metal output can be further increased by expanding the reduction chamber volume and increasing the number of crystallizers;

[0034] The present invention adopts a vacuum electrically heated horizontal reduction furnace and conveys block materials through a trolley mechanism, thereby overcoming the "sticking pot and glazing" phenomenon of the Pidgeon method and making it easier to realize the automatic operation of the equipment, thereby reducing the labor intensity of workers and improving production efficiency.

[0035] The present invention can effectively block the heat loss in the reduction chamber by heat conduction, heat convection and heat radiation by filling the space between the inner wall of the horizontal reduction furnace and the outer wall of the reduction chamber with heat insulation cotton, thereby overcoming the disadvantage of low thermal efficiency of the Pidgeon process.

[0036] The present invention adopts clean energy electricity as the heating energy of the electric heating element, especially green electricity energy from solar energy and wind power generation, which can overcome the large amount of smoke and greenhouse gas CO2 pollution generated by the Pidgeon process using coal gas or natural gas as fuel. It is a very vital low-carbon magnesium smelting technology under the background of "dual carbon". BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below in conjunction with the accompanying drawings.

[0038] Figure 1 This is a schematic diagram of the overall structure of an internal heating method vacuum magnesium smelting device of the present invention;

[0039] Figure 2 It is a schematic cross-sectional view of the overall structure of an internal heating method vacuum magnesium smelting device of the present invention;

[0040] Figure 3 yes Figure 2 Schematic diagram of the internal structure of a medium horizontal reduction furnace;

[0041] Figure 4 It is a schematic diagram of the internal structure of the horizontal reduction furnace of the present invention;

[0042] Figure 5 It is a schematic diagram of the structure of the trolley mechanism of the present invention;

[0043] Figure 6 It is a schematic diagram of the structure of the crystallization chamber of the present invention.

[0044] In the figure: 1. horizontal reduction furnace; 2. left flange; 3. right flange; 4. arched furnace door; 5. furnace door flange; 6. arched sealing cover; 7. sealing cover flange; 8. heat-resistant steel pipe; 9. refractory lining; 10. reduction chamber; 11. flat steel plate; 12. trolley track; 13. refractory brick; 14. electric heating element; 15. insulation cotton; 16. bottom heat-resistant steel plate; 17. middle refractory layer; 18. upper heat-resistant steel plate; 19. side plate; 20. insulation layer; 21. material tray; 22. block material; 23. traction track; 24. main pipeline; 25. crystallizer; 26. left port of main pipeline; 27. right port of main pipeline; 28. cooling chamber; 29. ​​cooling chamber pipeline; 30. crystallization barrel pipeline; 31. crystallization barrel; 32. bottom plate; 33. traction device; 34. lifting device. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be understood that terms such as "up", "down", "left", "right", "front" and "back" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, and a specific direction structure and operation. Therefore, they should not be understood as limitations on the present invention.

[0047] In addition, unless otherwise clearly specified and limited, the terms "installation", "setting", "connection", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Embodiment 1

[0049] See also Figure 1-6 As shown, this embodiment provides an internal heating method vacuum magnesium smelting device, including a vacuum electrically heated horizontal reduction furnace 1, a trolley mechanism for conveying block materials 22 in and out of the horizontal reduction furnace 1, and a crystallization chamber for collecting and condensing magnesium vapor.

[0050] See also Figure 2 As shown, in one embodiment, the shell of the horizontal reduction furnace 1 is cylindrical, with a length of about 7 meters and an inner diameter of about 3.4 meters. The shell of the horizontal reduction furnace 1 is welded by boiler and pressure vessel steel plates, the steel plates are made of Q245R steel, and the shell thickness is 10-30 mm.

[0051] See also Figure 3 As shown, the left end of the horizontal reduction furnace 1 is provided with an openable and closable arched furnace door 4 through a hinge, the outer peripheral fixed sleeve of the left end of the horizontal reduction furnace 1 is provided with a left flange 2, and the side of the left flange 2 close to the arched furnace door 4 is provided with a left sealing ring (not shown in the figure), and the edge fixed sleeve of the arched furnace door 4 is provided with a furnace door flange 5, and the furnace door flange 5 matches the left flange 2. When the arched furnace door 4 is closed, the furnace door flange 5 and the left flange 2 are fitted to form a seal, and the setting of the left sealing ring can achieve a better sealing effect. An arched sealing cover 6 is detachably installed at the right end of the horizontal reduction furnace 1 by bolts, a right flange 3 is provided on the outer peripheral fixed sleeve of the right end of the horizontal reduction furnace 1, a right sealing ring (not shown in the figure) is provided on the side of the right flange 3 close to the arched sealing cover 6, and a sealing cover flange 7 is provided on the edge fixed sleeve of the arched sealing cover 6. The sealing cover flange 7 matches the right flange 3. When the arched sealing cover 6 is installed to the right end of the horizontal reduction furnace 1, the sealing cover flange 7 fits with the right flange 3 to form a seal, and the setting of the right sealing ring can achieve a better sealing effect.

[0052] See also Figure 3 As shown, a flat steel plate 11 is fixed at the bottom of the inner cavity of the horizontal reduction furnace 1, and the reduction chamber 10 and the trolley track 12 are fixedly installed on the flat steel plate 11. The vertical distance between the flat steel plate 11 and the central axis of the horizontal reduction furnace 1 is 0.6-0.8 times the inner radius of the horizontal reduction furnace 1. In this embodiment, the flat steel plate 11 is 1.2 meters away from the central axis of the horizontal reduction furnace 1, which is about 0.7 times the inner radius of the horizontal reduction furnace 1. The reduction chamber 10 is made of refractory bricks 13, and the cross-sectional shape of the reduction chamber 10 perpendicular to the central axis of the horizontal reduction furnace 1 is a "∏" shape. A plurality of electric heating elements 14 are arranged on the wall surfaces on both sides of the reduction chamber 10. The electric heating elements 14 are silicon molybdenum rods, and the electric energy of the electric heating elements 14 is preferably from green electricity energy such as solar energy and wind power generation. The side of the reduction chamber 10 close to the arch furnace door 4 is open for the trolley mechanism to enter and exit the reduction chamber 10. The reduction chamber 10 is closed at one side close to the arched sealing cover 6 . A circular hole is provided at the center of the arched sealing cover 6 . A heat-resistant steel pipe 8 passes through the circular hole and extends into the reduction chamber 10 . The heat-resistant steel pipe 8 has a refractory lining 9 .

[0053] Furthermore, the space between the inner wall of the horizontal reduction furnace 1 and the outer wall of the reduction chamber 10 is filled with heat-insulating cotton 15 to prevent heat loss inside the reduction chamber 10.

[0054] See also Figure 1 and Figure 5As shown, in one embodiment, the trolley mechanism includes a bottom plate 32, a traction track 23 and a traction device 33 are arranged on the top of the bottom plate 32, the traction device 33 is arranged on the side of the bottom plate 32 away from the arch furnace door 4, and a lifting device 34 is arranged at the bottom of the bottom plate 32. The lifting device 34 drives the bottom plate 32 to rise and fall, so that the traction track 23 can be flush with the trolley track 12. The trolley mechanism also includes a heat-resistant base plate, a plurality of rollers are installed at the bottom of the heat-resistant base plate, and multiple layers of material trays 21 are arranged at intervals on the top of the heat-resistant base plate. A vertical side plate 19 is arranged at one end of the heat-resistant base plate, and a heat-insulating layer 20 is arranged on the side of the side plate 19 close to the traction track 23. The heat-resistant base plate includes a bottom heat-resistant steel plate 16, a middle fire-resistant layer 17 and a plurality of upper heat-resistant steel plates 18 arranged in sequence from bottom to top. A gap of about 10 mm is left between adjacent upper heat-resistant steel plates 18 to accommodate the thermal expansion of the heat-resistant steel plates.

[0055] It is worth noting that see Figure 3 As shown, after the heat-resistant substrate with the block material 22 enters the horizontal reduction furnace 1, the heat-resistant substrate and the side plate 19 are combined with the reduction chamber 10 to form a closed space. In this closed space, under high temperature and vacuum conditions, the block material 22 placed on the material tray 21 undergoes a reduction reaction and produces magnesium vapor. The trolley mechanism of this structure can hold about 3 tons of block material 22 at a time and can produce about 500 kilograms of metal magnesium.

[0056] See also Figure 6 As shown, in one embodiment, the crystallization chamber for collecting and condensing magnesium vapor includes a main pipeline 24 and a plurality of crystallizers 25 connected to both sides of the main pipeline 24. The main pipeline 24 is made of a heat-resistant steel pipe, the left port 26 of the main pipeline is connected to the heat-resistant steel pipe 8 leading to the reduction chamber, and the right port 27 of the main pipeline is connected to the vacuum, dust removal and air intake device outside the horizontal reduction furnace 1. The structure of the crystallizer 25 is the same as that of the crystallizer 25 of the traditional Pijiang method, and is mainly composed of a cooling chamber 28 and a crystallization barrel 31. One end of the cooling chamber 28 is connected to the inside of the main pipeline 24, and the open end of the crystallization barrel 31 is detachably sealed and plugged into the end of the cooling chamber 28 away from the main pipeline 24. The cooling chamber pipeline 29 is used to connect the circulating cooling water device and the vacuum device outside the horizontal reduction furnace 1, and the crystallization barrel pipeline 30 is used to connect the external vacuum device.

[0057] Embodiment 2

[0058] The method for producing metallic magnesium using an internal heat vacuum magnesium smelting device provided in Example 1 is as follows:

[0059] The honeycomb block material 22 is made from calcined dolomite, ferrosilicon and fluorite as raw materials.

[0060] The block materials 22 are evenly placed in a material tray 21 made of refractory material. The loaded material trays 21 are stacked on a heat-resistant substrate. A gap of about 50 mm is left between adjacent material trays 21 for magnesium vapor to escape.

[0061] The arched furnace door 4 is opened, and the lifting device 34 drives the bottom plate 32 to rise until the traction rail 23 is flush with the trolley rail 12 in the horizontal reduction furnace 1. The traction device 33 drives the heat-resistant substrate stacked with material trays 21 into the reduction chamber 10. After a closed space is formed in the reduction chamber 10, the traction rail 23 descends and the arched furnace door 4 is closed.

[0062] The vacuum valve of the vacuum device connected to the right port 27 of the main pipeline is opened, and the air pressure in the reduction chamber 10 is pumped to about 20 Pa, and then the vacuum valve of the vacuum device connected to the right port 27 of the main pipeline is closed. The vacuum valve of the vacuum device connected to the crystallization barrel pipeline 30 is opened, and the air in the reduction chamber 10 is continuously pumped out until the pressure in the reduction chamber 10 is less than 10 Pa.

[0063] The valve of the circulating cooling water device connected to the cooling chamber pipeline 29 is opened, and the crystallization barrel 31 is continuously cooled.

[0064] Then, the power of the resistance heating element 14 inside the reduction chamber 10 is turned on, and the temperature inside the reduction chamber 10 gradually rises to 1200° C. The block material 22 begins to undergo a reduction reaction and continuously produces magnesium vapor, which is captured by the crystallization barrel 31 and condensed into solid metallic magnesium in the crystallization barrel 31 .

[0065] After the material reduction reaction is completed, the power supply of the resistance heating element 14 in the reduction chamber 10 and the vacuum valve of the vacuum device connected to the crystallization barrel pipeline 30 are turned off, and the air intake valve of the air intake device connected to the right port 27 of the main pipeline is opened to fill the reduction chamber 10 with preheated nitrogen. When the air pressure inside and outside the reduction chamber 10 reaches equilibrium, the air intake valve of the air intake device connected to the right port 27 of the main pipeline is closed, the crystallization barrel 31 is taken out, the solid metal magnesium in the crystallization barrel 31 is obtained, and then the crystallization barrel 31 is returned to the cooling chamber 28. The arched furnace door 4 is opened, the traction track 23 is raised, and the heat-resistant substrate stacked with the material tray 21 is withdrawn to the outside of the horizontal reduction furnace 1. The traction track 23 is lowered, and the arched furnace door 4 is closed.

[0066] The material tray 21 containing the magnesium reduction slag on the trolley mechanism is removed, and then the above steps are repeated to enter a new round of magnesium reduction process.

[0067] The above is a detailed description of the preferred embodiments of the present invention, which cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An internal heating method vacuum magnesium smelting device, characterized in that: include: A horizontal reduction furnace (1), wherein an arched furnace door (4) that can be opened and closed is provided at the left end of the horizontal reduction furnace (1), and a removable arched sealing cover (6) is provided at the right end of the horizontal reduction furnace (1). A reduction chamber (10) and a trolley track (12) are fixedly provided on a flat steel plate (11) fixedly provided at the bottom of the inner cavity of the horizontal reduction furnace (1), wherein the trolley track (12) is located in the reduction chamber (10), and the reduction chamber (10) is made of refractory bricks (13), and the reduction chamber (10) ) The cross-sectional shape perpendicular to the axis direction of the horizontal reduction furnace (1) is in the shape of a letter V; the side of the reduction chamber (10) close to the arched furnace door (4) is open, and the side of the reduction chamber (10) close to the arched sealing cover (6) is closed; a heat-resistant steel pipe (8) extending into the reduction chamber (10) is inserted into the center of the arched sealing cover (6); the inner wall of the heat-resistant steel pipe (8) is attached with a refractory lining (9); and a plurality of electric heating elements (14) are arranged on the inner wall surfaces of both sides of the reduction chamber (10); The trolley mechanism comprises a bottom plate (32), a traction track (23) and a traction device (33) are arranged on the top of the bottom plate (32), a lifting device (34) for driving the bottom plate (32) to rise and fall is arranged on the bottom of the bottom plate (32), the trolley mechanism also comprises a heat-resistant base plate, a plurality of rollers are installed on the bottom of the heat-resistant base plate, a plurality of material trays (21) are arranged at intervals on the top of the heat-resistant base plate, a vertical side plate (19) is arranged at one end of the heat-resistant base plate, and a heat-insulating layer (20) is arranged on the side of the side plate (19) close to the traction track (23); The crystallization chamber comprises a main pipeline (24) and a plurality of crystallizers (25) connected to both sides of the main pipeline (24); a left port (26) of the main pipeline (24) is connected to a heat-resistant steel pipe (8); and a right port (27) of the main pipeline is connected to vacuum, dust removal and air intake equipment outside the horizontal reduction furnace (1).

2. The internal heating method vacuum magnesium smelting device according to claim 1 is characterized in that: The space between the inner wall of the horizontal reduction furnace (1) and the outer wall of the reduction chamber (10) is filled with heat-insulating cotton (15).

3. The internal heating method vacuum magnesium smelting device according to claim 1 is characterized in that: The vertical distance between the flat steel plate (11) and the central axis of the horizontal reduction furnace (1) is 0.6-0.8 times the inner radius of the horizontal reduction furnace (1).

4. The internal heating method vacuum magnesium smelting device according to claim 1 is characterized in that ； A left flange (2) is provided on the outer peripheral fixed sleeve of the left end of the horizontal reduction furnace (1); a left sealing ring is provided on the side of the left flange (2) close to the arch furnace door (4); a furnace door flange (5) is provided on the edge fixed sleeve of the arch furnace door (4); and the furnace door flange (5) matches the left flange (2); A right flange (3) is provided on the outer peripheral fixed sleeve of the right end of the horizontal reduction furnace (1), a right sealing ring is provided on the side of the right flange (3) close to the arched sealing cover (6), a sealing cover flange (7) is provided on the edge fixed sleeve of the arched sealing cover (6), and the sealing cover flange (7) matches the right flange (3).

5. The internal heating method vacuum magnesium smelting device according to claim 1, characterized in that: The heat-resistant substrate comprises a bottom heat-resistant steel plate (16), a middle fire-resistant layer (17) and a plurality of upper heat-resistant steel plates (18) which are arranged in sequence from bottom to top.

6. The internal heating method vacuum magnesium smelting device according to claim 1, characterized in that: A heat-insulating layer (20) is provided on one side of the side plate (19) close to the traction track (23).

7. The internal heating method vacuum magnesium smelting device according to claim 1 is characterized in that: The crystallizer (25) comprises a cooling chamber (28) and a crystallization barrel (31). One end of the cooling chamber (28) is connected to the interior of the main pipeline (24). The open end of the crystallization barrel (31) is detachably sealed and plugged into an end of the cooling chamber (28) away from the main pipeline (24).

8. An internal heating method for vacuum magnesium smelting, which is performed using an internal heating method for vacuum magnesium smelting device according to any one of claims 1 to 7, characterized in that: include: S1, forming the raw materials into honeycomb block materials (22); S2, the block material (22) is evenly placed on the material tray (21), and the loaded material trays (21) are stacked on the heat-resistant substrate of the trolley mechanism in sequence, leaving gaps between the material trays (21) for magnesium vapor to escape; S3, the arched furnace door (4) is opened, and the lifting device (34) drives the bottom plate (32) to rise until the traction track (23) is flush with the trolley track (12) in the horizontal reduction furnace (1), and the heat-resistant substrate stacked with the material tray (21) is driven into the reduction chamber (10) under the action of the traction device (33). After a closed space is formed in the reduction chamber (10), the arched furnace door (4) is closed; S4, the air pressure inside the reduction chamber (10) is pumped down to less than 10 Pa through an external device, and the circulating cooling water of the crystallizer (25) is connected, and the power supply of the resistance heating element (14) inside the reduction chamber (10) is turned on, the temperature inside the reduction chamber (10) reaches 1200° C., the block material (22) begins to undergo a reduction reaction and continuously produces magnesium vapor, which is captured by the crystallizer (25) and condensed into solid metal magnesium; S5, when the material reduction reaction is finished and the internal and external pressures of the horizontal reduction furnace (1) reach equilibrium, the crystallizer (25) can be taken out to obtain solid magnesium metal, the arched furnace door (4) is opened, the heat-resistant substrate stacked with the material tray (21) is withdrawn to the outside of the horizontal reduction furnace (1), and the arched furnace door (4) is closed; S6, removing the material tray (21) containing the magnesium reduction slag on the trolley mechanism, and then repeating steps S1-S5 to enter a new round of magnesium reduction process.

9. The internal heating vacuum magnesium smelting method according to claim 8, characterized in that: The raw materials in step S1 include burnt dolomite, ferrosilicon and fluorite.

10. The internal heating vacuum magnesium smelting method according to claim 8, characterized in that: In step S1, the gap between adjacent material trays (21) is 50 mm.

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