Magnesium smelting furnace and magnesium smelting method

Abstract

The invention discloses a magnesium smelting furnace and a magnesium smelting method, and belongs to the technical field of metal magnesium smelting production. The magnesium smelting furnace comprises a furnace body, a reaction container and an electric heating element, the furnace body is provided with a furnace chamber, and at least one reaction container is accommodated in the furnace chamber; the reaction container is provided with a reaction chamber, and the reaction chamber is of an annular cavity structure; the reaction container comprises an outer cylinder and an inner cylinder which are coaxially nested; the outer side of the outer cylinder and the inner side of the inner cylinder are each provided with at least one electric heating element arranged in the circumferential direction. According to the magnesium smelting furnace, heat supply on the inner side and the outer side can be achieved, compared with a traditional single-side heating mode, the design adopts a two-way radial heat transfer mechanism, the heat flow transfer path is remarkably shortened, and the radial temperature gradient is effectively reduced. By means of the improvement, the reaction rate of the material ball layer in the reaction container is increased, the time needed by the reduction process is greatly shortened, and therefore the production efficiency is remarkably improved. According to measurement and calculation, the single-furnace single-day magnesium yield of the magnesium smelting furnace can be increased to more than three times of the original level.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium metal smelting production, and in particular to a magnesium smelting furnace and a magnesium smelting method. Background Art

[0002] The production of raw magnesium in the existing technology mainly adopts the silicon thermal method, the principle of which is to grind and press calcined white, 75 ferrosilicon reducing agent and a small amount of fluorite powder into balls, and then carry out smelting reaction under high temperature and vacuum conditions. In industrial production, the heat required for the smelting reaction is usually provided by external fuel heating. However, this heat supply method has the limitation of a one-way heat transfer path, which leads to the formation of a significant temperature gradient in the reaction system. Specifically, the balls near the reaction center area have a longer heat conduction path and a slower temperature rise rate, thereby extending the overall smelting reaction time. This lack of heat transfer efficiency not only reduces the reaction rate of the ball layer, but also leads to a decrease in magnesium production, affecting the economy and production efficiency of the process. Summary of the Invention

[0003] The purpose of the present invention is to solve the technical problem that the external fuel heating method used in the prior art has a one-way heat transfer path, resulting in a large radial temperature distribution gradient in the reaction system, prolonging the smelting reaction time and thus reducing the magnesium production efficiency.

[0004] The purpose of the present invention is to adopt the following technical solutions to achieve:

[0005] The present invention provides a magnesium smelting furnace, comprising: a furnace body, a reaction container and an electric heating element;

[0006] The furnace body has a furnace cavity, in which at least one reaction container is placed; the reaction container has a reaction chamber, and the reaction chamber is an annular cavity structure;

[0007] The reaction container comprises: an outer cylinder and an inner cylinder coaxially nested;

[0008] At least one circumferentially arranged electric heating element is respectively provided on the outer side of the outer cylinder and the inner side of the inner cylinder.

[0009] Optionally, the reaction chamber is formed between the inner wall of the outer cylinder and the outer wall of the inner cylinder; at least one circumferentially arranged electric heating element is respectively provided on the outer side of the outer wall of the outer cylinder and the inner side of the inner wall of the inner cylinder.

[0010] Optionally, the plurality of electric heating elements located on the outside of the outer cylinder and the inside of the inner cylinder are distributed in a circumferential array.

[0011] Optionally, the reaction vessel further comprises: a feeding component and a slag discharging component;

[0012] The feeding component includes: an upper cover and a first pipe; the upper cover is arranged on the top of the outer cylinder and the inner cylinder; the upper cover has a feeding inlet, and the feeding inlet is connected to the reaction chamber through the first pipe;

[0013] The slag discharge component includes: a lower cover and a second pipe; the lower cover is arranged at the bottom of the outer cylinder and the inner cylinder; the lower cover has a slag discharge outlet, and the slag discharge outlet is connected to the reaction chamber through the second pipe.

[0014] Optionally, the magnesium smelting furnace also includes: a magnesium crystallization device arranged on the outside of the furnace body; the magnesium crystallization device includes: a crystallization chamber, a cooling device and a third pipe; the crystallization chamber is connected to the reaction chamber through the third pipe; the cooling device is arranged on the third pipe or on the outside of the crystallization chamber.

[0015] Optionally, the furnace body includes: an outer shell layer, an insulation layer and a refractory layer; the refractory layer is arranged around the outside of the reaction container; the electric heating element located outside the outer cylinder is placed between the outer cylinder and the refractory layer; the insulation layer is placed between the outer shell layer and the refractory layer.

[0016] Optionally, a first gap is set between the outer side wall of the outer cylinder and the corresponding electric heating element, and a second gap is set between the inner side wall of the inner cylinder and the corresponding electric heating element, and the gap distance of the first gap and the gap distance of the second gap are both between 1mm and 20mm.

[0017] Optionally, the ratio of the radius of the inner cylinder to the radius of the outer cylinder is in a range of 20% to 80%.

[0018] Optionally, the annular width of the reaction chamber is 80 mm to 300 mm.

[0019] The present invention also provides a magnesium smelting method, which is applied to the magnesium smelting furnace described above, wherein the magnesium smelting furnace further comprises: a magnesium crystallization device disposed outside the furnace body; the magnesium crystallization device comprises: a crystallization chamber, a cooling device, and a third pipe; the crystallization chamber is connected to the reaction chamber through the third pipe; the cooling device is disposed on the third pipe or outside the crystallization chamber;

[0020] The method comprises:

[0021] Adding magnesium smelting raw material balls into the reaction chamber;

[0022] The electric heating elements on the outer side of the outer cylinder and the inner side of the inner cylinder are controlled to heat the raw material balls in the reaction chamber, so that the raw material balls in the reaction chamber undergo a reduction reaction to produce magnesium vapor; wherein the temperature of the outer cylinder wall is controlled to be 1200° C.±25° C., and the time required to complete the reduction reaction is 4 hours to 6 hours;

[0023] The magnesium vapor enters the crystallization chamber through the third pipe, and the temperature in the crystallization chamber is controlled by the cooling device to be cooled to 450° C. to 550° C. to crystallize and produce crude magnesium;

[0024] The crude magnesium is taken out and subjected to a post-demagnesium process.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] On the one hand, the magnesium smelting furnace provided by the present invention realizes heating on both the inside and outside sides by constructing a reaction chamber with an annular structure in the magnesium smelting furnace and arranging electric heating elements on the outside of the outer ring and the inside of the inner ring of the reaction chamber. Compared with the traditional single-sided heating method, this design adopts a two-way radial heat transfer mechanism, which significantly shortens the heat flow transfer path and effectively reduces the radial temperature gradient. This improvement not only accelerates the reaction rate of the ball layer in the reaction vessel, but also greatly shortens the time required for the reduction process, thereby significantly improving production efficiency. It is estimated that the magnesium output of a single furnace per day of this magnesium smelting furnace can be increased to more than three times the original level.

[0027] Furthermore, the magnesium smelting method provided by the present invention effectively separates the charging, magnesium tapping, and slag tapping processes in time and space. This optimized design significantly reduces dust and high-temperature flue gas emissions during operation, significantly improving the production environment and enhancing the environmental friendliness and operational safety of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is a schematic diagram of the front structure of a magnesium smelting furnace according to some embodiments of the present invention;

[0029] Figure 2 This is a schematic top view of the reaction vessel and the electric heating element provided by the present invention;

[0030] Figure 3 1 is a schematic top view of a cylindrical magnesium smelting furnace having three reaction chambers according to some embodiments of the present invention;

[0031] Figure 4 1 is a schematic top view of a rectangular magnesium smelting furnace having three reaction chambers according to some embodiments of the present invention;

[0032] Figure 5 1 is a schematic top view of a rectangular magnesium smelting furnace having six reaction chambers according to some embodiments of the present invention;

[0033] Figure 6 It is a schematic diagram of the top structure of a traditional reduction tank and a reaction vessel according to an embodiment of the present invention.

[0034] Reference numerals:

[0035] Furnace body 100; outer shell 101; insulation layer 102; refractory layer 103;

[0036] Reaction vessel 1; reaction chamber 1a; outer cylinder 11; inner cylinder 12;

[0037] Feeding component 13; upper cover 131; first pipe 132; distributor 133; switch valve 134;

[0038] Slag discharge component 14; lower cover 141; second pipe 142;

[0039] Reduction tank 2;

[0040] Electric heating element 200;

[0041] Magnesium crystallization device 300; crystallization chamber 301; third pipeline 302; cooling device 303; short pipe 304; fourth pipeline 305. DETAILED DESCRIPTION

[0042] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0043] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0044] Raw magnesium is mainly produced by the silicothermic method. The process principle is that the raw materials, calcined white, 75% ferrosilicon reducing agent and a small amount of fluorite powder are ground and pressed into balls, and then a smelting reaction as shown in formula (1) occurs under high temperature and vacuum conditions. ; (1)

[0045] In industrial production, the above-mentioned smelting reaction is usually carried out in a high-temperature environment of approximately 1200°C in the reduction tank 2, and a vacuum of approximately 10Pa is maintained in the tank to ensure the purity of the reaction product. The heat required for the reduction reaction is mainly provided by external fuel heating. However, this heat supply method has significant limitations, resulting in a long reduction time, usually exceeding 10 hours, and in some cases even reaching more than 18 hours. After analysis, the main reason for the long reduction time is the unidirectionality of the heat transfer path: the heat generated by the fuel combustion needs to be transferred layer by layer through the outer wall of the reduction tank 2 to the ball layer inside the tank. This process forms a significant temperature gradient. Due to the long heat conduction path, the temperature rise rate of the balls near the center of the tank is slower, thereby extending the overall reduction reaction time.

[0046] This one-way heat transfer method limits the radial thickness of the ball layer within the tank (excessive thickness will further extend the reduction time), which in turn limits the amount of material loaded per tank and the amount of magnesium produced. Currently, the magnesium production per tank using the horizontal tank method is generally 20-30 kg, while the magnesium production per tank using the vertical tank method is approximately 100 kg.

[0047] To improve heat transfer efficiency, industry professionals have attempted to shorten reduction time and increase magnesium production per tank by adding enhanced heat transfer structures. However, in actual operation, these enhanced structures have exposed problems such as high-temperature deformation and blockages in charge feeding and discharge, and have not yet been successfully applied to industrial production.

[0048] Furthermore, to increase magnesium production, the reduction furnace requires multiple reduction tanks 2, resulting in a large equipment footprint. Furthermore, the existing installation method for the magnesium crystallizer within the reduction tank 2 limits the synchronization of charging and removing magnesium, resulting in extended process operation time and complex procedures. During the removal of the lid, magnesium removal, and charging processes, the reduction tanks 2 must be left open at high temperatures, resulting in a large amount of dust particles being dispersed in the operating environment, creating a harsh working environment.

[0049] The above problems collectively hinder further improvements in production efficiency. Specifically, the temperature gradients caused by the one-way heat transfer method, prolonged reduction time, limited single-tank loading capacity, and insufficient magnesium production, coupled with the technical difficulties of the enhanced heat transfer structure in practical applications (such as high-temperature deformation, charging and discharging blockages), and the increased floor space and process complexity brought about by the multi-tank layout (such as the inability to simultaneously charge and remove magnesium, and dust pollution caused by high-temperature open-tank operations), not only reduce the reaction rate but also lead to a decrease in magnesium production, affecting the process economy and production efficiency.

[0050] In light of this, to improve heat supply and optimize the heat transfer path, the inventors have researched and designed a magnesium smelting furnace with a reaction chamber. This furnace constructs an annular, sealed reaction chamber with annular electric heating elements placed on both the outer and inner walls of the reaction chamber, creating a coaxial dual-ring heat source layout. By establishing a bidirectional radial heat transfer mechanism, the heat flow path is significantly shortened, optimizing the temperature gradient within the reaction chamber. This increases the reaction rate, shortens the reduction reaction time, and significantly improves production efficiency.

[0051] The following is further described with reference to specific examples.

[0052] Figure 1 1 is a schematic diagram of the front structure of a magnesium smelting furnace according to some embodiments of the present invention; Figure 2 This is a schematic diagram of the top view of the reaction container and the electric heating element provided by the present invention. Figure 1 and Figure 2 An embodiment of the present invention provides a magnesium smelting furnace, which includes: a furnace body 100, a reaction vessel 1 and an electric heating element 200; the furnace body 100 has a furnace cavity, in which at least one reaction vessel 1 is placed; the reaction vessel 1 has a reaction chamber 1a, and the reaction chamber 1a has an annular cavity structure; the reaction vessel 1 includes: an outer cylinder 11 and an inner cylinder 12 coaxially nested; at least one circumferentially arranged electric heating element 200 is respectively provided on the outer side of the outer cylinder 11 and the inner side of the inner cylinder 12.

[0053] During the magnesium smelting process, furnace body 100 primarily provides insulation and sealing, minimizing heat loss within the furnace, maintaining a high-temperature reaction environment, and controlling the reducing atmosphere and vacuum level to ensure reaction efficiency while preventing air ingress and magnesium oxidation. Furnace body 100 must possess sufficient mechanical strength and heat resistance to withstand the high temperatures and stresses generated during the reaction, ensuring long-term stable operation. Materials for furnace body 100 include high-alumina bricks, silicon carbide bricks, or carbon steel plates.

[0054] The shape of the furnace body 100 can be designed to be cylindrical, rectangular or prism-shaped.

[0055] In order to maintain the high temperature environment required for the magnesium smelting reaction, the furnace body 100 needs to be insulated to reduce heat loss and ensure the stability of the reaction temperature. Figure 2 In some embodiments, the furnace body 100 may include: an outer shell layer 101, an insulation layer 102 and a refractory layer 103; the refractory layer 103 is arranged around the outside of the reaction vessel 1; the electric heating element 200 located outside the outer ring of the reaction chamber 1a is placed between the reaction vessel 1 and the refractory layer 103; the insulation layer 102 is placed between the outer shell layer 101 and the refractory layer 103.

[0056] Among them, the material of the outer shell layer 101 can be high-strength, high-temperature resistant materials such as high-alumina bricks, silicon carbide bricks or carbon steel; the insulation layer 102 is filled in the space formed between the inner wall of the outer shell layer 101 and the outer wall of the refractory layer 103, and its material can be low thermal conductivity, lightweight insulation materials such as diatomaceous earth bricks, perlite bricks or ceramic fibers; the material of the refractory layer 103 can be high refractoriness and excellent corrosion resistance materials such as magnesia bricks, alumina fibers or silicon carbide.

[0057] It should be noted that the furnace body 100 may include multiple reaction vessels 1, each of which is surrounded by a refractory layer 103. The electric heating element 200 located on the outside is placed in the space between the reaction vessel 1 and the refractory layer 103. The insulation layer 102 fills the remaining space in the furnace cavity excluding the area surrounded by the multiple refractory layers 103.

[0058] The outer cylinder 11 and the inner cylinder 12 can be made of high temperature resistant alloy material. The coaxial nested arrangement design can improve the consistency of the ball reaction in the reaction chamber 1a.

[0059] The gap between the inner wall of the outer cylinder 11 and the outer wall of the inner cylinder 12 forms the reaction chamber 1a; at least one circumferentially arranged electric heating element 200 is respectively provided on the outer side of the outer wall of the outer cylinder 11 and the inner side of the inner cylinder 12.

[0060] The reaction chamber 1a is annular in structure and is used to accommodate the pellets required for magnesium smelting reaction and perform magnesium smelting reduction reaction. Multiple reaction chambers 1a can be configured in the furnace cavity of the furnace body 100 to perform smelting reaction simultaneously. Figure 3 1 is a schematic top view of a cylindrical magnesium smelting furnace having three reaction chambers according to some embodiments of the present invention; Figure 4 1 is a schematic top view of a rectangular magnesium smelting furnace having three reaction chambers according to some embodiments of the present invention; Figure 5 Schematic diagram of the top view of a rectangular magnesium smelting furnace with 6 reaction chambers in some embodiments provided by the present invention. Figure 3 As shown, three reaction vessels 1 are provided in the cylindrical furnace body 100. The preferred arrangement is to connect the center points of the reaction chambers 1a in the three reaction vessels 1 to form an equilateral triangle; Figure 4 and Figure 5 As shown, a rectangular furnace body 100 can accommodate three or six reaction vessels 1, evenly distributed along its length. For example, during installation, a cylindrical furnace body 100 containing three reaction chambers is used as an example. The furnace body 100 is rolled from 10mm thick carbon steel sheet and has a diameter of 4m. The center position of each reaction chamber 1a is predetermined, and the outer diameter of the chamber is reserved for 1m.

[0061] Traditional magnesium smelting reactions typically occur in multiple reduction tanks 2, which are arranged in parallel or staggered configurations within the furnace body 100 (e.g., 20, 35, 63, etc.). In contrast, the embodiments of the present invention utilize an annular reaction vessel 1, consisting of only two cylindrical bodies nested within each other. Compared to the traditional arrangement of multiple reduction tanks 2, this design offers advantages such as a simple internal structure within the furnace body 100, flexible layout, ease of operation, and a small footprint. Furthermore, it fully utilizes the internal space of the furnace body 100, significantly increasing magnesium production.

[0062] The electric heating element 200 is primarily used to provide heat for the magnesium smelting reaction. It can be in the form of a resistance wire, electric heating tube, electric heating plate, electric heating rod, or heating sheet, and can be made of graphite, silicon carbide, iron-chromium-aluminum, or stainless steel. Traditionally, heat supply for magnesium smelting reactions has typically been achieved through external fuel heating, including pulverized coal, coke oven gas, semi-coke gas, producer gas, and natural gas. In contrast, this embodiment utilizes electric heating, which offers significant advantages over traditional fuel heating, including pollution-free operation, high efficiency, precise temperature control, and easy installation and maintenance. It also facilitates both internal and external heating.

[0063] The electric heating element 200 can adopt an annular or non-annular structure. The annular electric heating element 200 can be arranged on the outside of the outer cylinder 11 or the inside of the inner cylinder 12 respectively. For example, a group of resistance wires can be spirally wound on the outer wall of the outer cylinder 11 and the inner wall of the inner cylinder 12. The non-annular electric heating element 200 can be composed of multiple independent elements distributed circumferentially on the outside of the outer cylinder 11 or the inside of the inner cylinder 12, and connected in series or in parallel. Preferably, the multiple electric heating elements 200 are distributed in a circumferential array to significantly improve the uniformity of the heating temperature of the ball layer in the reaction chamber 1a. For example, Figure 2 As shown, 9 electric heating elements 200 are distributed in an array along the inner circumferential direction of the inner wall of the inner cylinder 12 , and 24 electric heating elements are distributed in an array along the outer circumferential direction of the outer wall of the outer cylinder 11 .

[0064] In addition, the electric heating element 200 can be installed on the side wall or placed near the side wall. In some embodiments, it is preferred to place the electric heating element 200 near the outer wall of the outer cylinder 12 or the inner wall of the inner cylinder 12, and to leave a certain gap between the wall and the electric heating element 200. This design can avoid direct contact between the raw material balls and the electric heating element 200, thereby reducing the corrosion of the raw material balls on the electric heating element 200 and extending its service life. Figure 2 A first gap is set between the outer wall of the outer cylinder 11 and the corresponding electric heating element 200, and a second gap is set between the inner wall of the inner cylinder 12 and the corresponding electric heating element 200. The gap distance of the first gap and the gap distance of the second gap are preferably 10 mm.

[0065] It is understood that a single set of electric heating elements 200 can be used as an independent load, conveniently leading out of the furnace body through the electrode connector and connecting to the power supply equipment, which has the advantages of load balancing and convenient removal and replacement. In addition, it can also be electrically connected to a temperature control device, which can accurately control the heating temperature of the electric heating elements 200, thereby achieving precise regulation of the reduction reaction temperature within the furnace body 100.

[0066] The use of internal and external double-sided heating can achieve bidirectional heat transfer in the radial direction of the ball layer. Compared with the single-sided heating method, it significantly shortens the length of the heat flow transfer path and reduces the radial temperature gradient, thereby effectively shortening the reduction time and increasing the magnesium production.

[0067] The following uses the ratio of the radius of the outer cylinder 11 to the radius of the inner cylinder 12 of the embodiment of the present invention as an example of 2:1 to calculate the magnesium smelting reduction reaction time of the traditional reduction tank 2 with a single-sided heating method and the annular reaction vessel 1 with a double-sided heating method according to the embodiment of the present invention under the condition of producing the same amount of crude magnesium.

[0068] Figure 6 Schematic diagram of the top view of the traditional reduction tank 2 and the reaction vessel of an embodiment of the present invention. Figure 6 As shown, the radius of the reduction tank 2 is r1, and the annular width of the reaction chamber 1a of the embodiment of the present invention is r 2， The radius of the outer cylinder 11 is a=2r2, and the radius of the inner cylinder 12 is b=r2; the reduction tank 2 and the reaction vessel 1 both adopt a vertical tank structure, and the heights of the two are the same, both h; the reaction volume of the reduction tank 2 is V1, and the reaction volume of the reaction vessel 1 of the embodiment of the present invention is V2.

[0069] According to the volume calculation formula, the reaction volume V1 of the reduction tank 2 can be calculated as shown in the following formula (1). The reaction volume V2 of the reaction container 1 of the embodiment of the present invention can be calculated as shown in the following formula (2):

[0070] ; (1)

[0071] ; (2)

[0072] Since the magnesium production is the same, the relationship between V1 and V2 is:

[0073] ; (3)

[0074] Therefore, the relationship between the radius r1 of the reduction tank 2 and the width r2 of the reaction chamber 1a can be calculated by the above calculation formulas (1), (2) and (3):

[0075] ; (4)

[0076] According to Fourier's law, in the unsteady-state heat transfer model, the heat transfer time is proportional to the square of the path length. Therefore, the ratio of the heat transfer time t2 of the reaction chamber 1a to the heat transfer time t1 of the reduction tank 2 is:

[0077] .

[0078] In summary, it has been calculated that compared with the traditional industrial silicon thermal method of magnesium smelting technology (single-sided heating method with external fuel), the double-sided heating method can shorten the reduction time required to produce the same amount of crude magnesium to 1 / 3 of that of the single-sided heating method; conversely, within the same reduction time, the crude magnesium output can be increased to more than 3 times that of the single-sided heating method.

[0079] Furthermore, compared to single-sided heating, the radial heat transfer path is significantly shortened with dual-sided heating. Even if the thickness of reaction vessel 1 (the thickness of outer cylinder 11 or inner cylinder 12) is increased, the magnesium reduction reaction time will not be significantly prolonged. Therefore, while ensuring the reduction reaction time remains constant, the capacity of reaction chamber 1a can be increased compared to a single-sided heating reduction tank 2, significantly increasing magnesium production and effectively boosting production capacity.

[0080] Furthermore, reducing the spacing between adjacent electric heating elements 200 can significantly improve the uniformity of heat transfer in the pellet layer, thereby improving production efficiency. Reducing the annular width of the reaction chamber 1a can shorten the radial heat transfer path, further improving production efficiency. However, with the same charge volume, reducing the annular width of the reaction chamber 1a will result in an increase in its circumference. To ensure heating uniformity, the number of electric heating elements 200 needs to be increased, which in turn leads to increased energy consumption. On the other hand, increasing the annular width of the reaction chamber 1a can also effectively alleviate the radial expansion force of the pellet layer, which is beneficial to the discharge of the reducing slag. Therefore, there is a reasonable range of values ​​for the annular width. Taking various factors into consideration, the annular width of the reaction chamber 1a in the reaction vessel 1 should be designed to be 80~300mm, and preferably 240mm.

[0081] Similarly, increasing the annular width of reaction chamber 1a will extend the radial heat transfer path of the pellet layer, while decreasing the annular width will reduce the capacity of reaction chamber 1a, thereby reducing magnesium production. Therefore, the ratio of the radius of inner cylinder 12 to that of outer cylinder 11 is constrained and should be controlled within the range of 20% to 80%. Under optimal conditions, the ratio of the radius of inner cylinder 12 to that of outer cylinder 11 should be set at 50%.

[0082] In the technical solution of the embodiment of the present invention, a ring-shaped reaction chamber 1a is constructed in the magnesium smelting furnace, and electric heating elements 200 are respectively arranged on the outside of the outer ring and the inside of the inner ring of the reaction chamber 1a to achieve heating on both the inside and outside sides. Compared with the traditional single-sided heating method, this design adopts a two-way radial heat transfer mechanism, which significantly shortens the heat flow transfer path and effectively reduces the radial temperature gradient. This improvement not only accelerates the reaction rate, but also greatly shortens the time required for the reduction reaction, thereby significantly improving production efficiency. It is estimated that the magnesium output of a single furnace per day of this magnesium smelting furnace can be increased to more than three times the original level.

[0083] In some embodiments, see Figure 1 The reaction vessel 1 may further include a feeding component 13. Specifically, the feeding component 13 may include an upper cover 131 and a first conduit 132. The upper cover 131 is positioned on top of the outer cylinder 11 and the inner cylinder 12. The upper cover 131 has a feeding inlet, which communicates with the reaction chamber 1a via the first conduit 132. The feeding component 13 may also include a distributor 133. The distributor 133 covers the top of the inner cylinder 12 and may be designed in the shape of a trapezoidal cone. The distributor 133 not only seals the inner cylinder 12 but also evenly directs the pellets transported from the first conduit 132 into the reaction chamber 1a. A switch valve 134 is provided at the feeding inlet. When feeding, the switch valve 134 is opened, allowing the pellets to enter the first conduit 132 through the feeding inlet and then be transported into the reaction chamber 1a via the first conduit 132. Once the reaction chamber 1a is filled with pellets, the switch valve 134 is closed. In actual installation, the upper cover 131 is formed integrally by the upper flange and the blocks at its bottom. The blocks are cast from refractory materials, and an insulation layer is provided on the upper surface of the blocks.

[0084] Further, in some embodiments, see Figure 1 The reaction vessel 1 may further include a slag discharge component 14, comprising a lower cover 141 and a second conduit 142. The lower cover 141 is disposed on the bottom of the outer cylinder 11 and the inner cylinder 12, and has a slag discharge outlet connected to the reaction chamber 1a via the second conduit 142. In actual installation, the lower cover 141 is integrally formed by a lower flange and a block disposed on top thereof. The block is cast from refractory material, has an insulating layer on its lower surface, and an annular prefabricated member on its upper surface for supporting the inner cylinder 12 and the electric heating element 200. The annular prefabricated member can be made of fire-resistant and high-temperature-resistant steel.

[0085] Continue reading Figure 1In some embodiments, the magnesium smelting furnace may further include: a magnesium crystallization device 300 arranged outside the furnace body 100; the magnesium crystallization device 300 may specifically include: a crystallization chamber 301, a cooling device 303 and a third pipe 302; the crystallization chamber 301 is connected to the reaction chamber 1a through the third pipe 302; the cooling device 303 is arranged on the third pipe 302 or outside the crystallization chamber 301.

[0086] The magnesium crystallization device 300 is used to collect the magnesium generated in the reaction chamber 1a. The magnesium vapor generated during the reduction reaction enters the crystallization chamber 301 through the third pipe 302, where the crystallization process is completed. The cooling device 303 is used to cool the magnesium vapor to promote its condensation and crystallization. After the magnesium vapor condenses into crude magnesium, it is removed and subjected to the subsequent de-magnesium treatment process. The cooling device 303 can be installed on the outer wall of the third pipe 302, or on or near the outer wall of the crystallization chamber 301.

[0087] A magnesium crystallization device 300 can be docked with a reaction chamber 1a, wherein the crystallization chamber 301 is connected to the bottom of the reaction chamber 1a via a third conduit 302, and the connection port is located at least 200 mm above the bottom end surface of the inner cylinder 12. In addition, the magnesium crystallization device 300 may also include a fourth conduit 305, through which the crystallization chamber 301 is connected to a vacuum pump, thereby achieving a vacuum treatment of the entire interior space of the furnace body 100.

[0088] To ensure the vacuum level within furnace body 100 during the magnesium smelting process, third conduit 302 can be designed as a vacuum tube and connected to the bottom of reaction chamber 1a via a small short pipe, serving as a circulation channel for magnesium vapor. The short pipe can be made of heat-resistant stainless steel, and its cross-section can be designed to be rectangular or circular. The short side of the rectangle or the diameter of the circle should be smaller than the equivalent diameter of the pellet to prevent the pellet from entering the vacuum conduit through the short pipe. To prevent electrical conduction and short-circuiting of heating element 200, an insulating layer is required on the outside of the short pipe.

[0089] An embodiment of the present invention further provides a magnesium smelting method using the magnesium smelting furnace described in the above embodiment, wherein the magnesium smelting furnace comprises: a furnace body 100, a reaction vessel 1, and an electric heating element 200; the furnace body 100 has a furnace cavity, in which at least one reaction vessel 1 is accommodated; the reaction vessel 1 has a reaction chamber 1a, which has an annular cavity structure; the reaction vessel 1 comprises: an outer cylinder 11 and an inner cylinder 12 coaxially nested; at least one circumferentially arranged electric heating element 200 is respectively provided on the outer side of the outer cylinder 11 and the inner side of the inner cylinder 12;

[0090] The magnesium smelting furnace further includes: a magnesium crystallization device 300 disposed outside the furnace body 100; the magnesium crystallization device 300 may specifically include: a crystallization chamber 301, a cooling device 303, and a third pipe 302; the crystallization chamber 301 is connected to the reaction chamber 1a through the third pipe 302; the cooling device 303 is disposed on the third pipe 302 or outside the crystallization chamber 301;

[0091] The method comprises the following steps:

[0092] Step S101: adding magnesium smelting raw material balls into the reaction chamber 1a;

[0093] Step S102: Controlling the electric heating elements 200 on the outer side of the outer ring and the inner side of the inner ring of the reaction chamber 1a to heat the raw material balls in the reaction chamber 1a, causing the raw material balls in the reaction chamber 1a to undergo a reduction reaction to produce magnesium vapor; wherein, the outer cylinder wall temperature is controlled to be 1200°C ± 25°C, and the reduction reaction time required to complete is 4 hours to 6 hours;

[0094] Step S103: magnesium vapor enters the crystallization chamber 301 through the third pipe 302, and the temperature in the crystallization chamber 301 is controlled to drop to 450-550° C. to crystallize and produce crude magnesium;

[0095] Step S104: taking out the crude magnesium and performing a post-demagnesium process.

[0096] Among them, in step S101, the raw materials for magnesium smelting are usually calcined white, 75% ferrosilicon reducing agent and a small amount of fluorite powder, which are ground and pressed into balls and then added into the reaction chamber 1a to form a ball pile layer.

[0097] In step S102, the electric heating element 200 can be electrically connected to the temperature control device outside the furnace body 100 through a wire, and the heating temperature of the electric heating element 200 is controlled by the temperature control device, thereby controlling the temperature of the reduction reaction in the reaction chamber 1a; the reaction chamber 1a is connected to the vacuum pump outside the furnace body 100 through a pipeline, and the reaction chamber 1a is evacuated by the vacuum pump to maintain a vacuum environment to prevent the reduction product from being oxidized.

[0098] In step S103, the magnesium produced by the reduction reaction enters the crystallization chamber 301 in the form of high-temperature gas. The magnesium vapor can be cooled by a cooling device 303 installed in the third pipe 302 or outside the crystallization chamber 301 to condense and crystallize the magnesium in the crystallization chamber 301.

[0099] In step S104, the crude magnesium produced by crystallization is taken out from the crystallization chamber 301 and subjected to subsequent purification methods such as distillation and refining to remove impurities in the crude magnesium to obtain high-purity magnesium metal.

[0100] In the technical solution of the present invention, the processes of charging, magnesium discharge, and slag discharge are effectively separated in time and space. This optimized design significantly reduces dust and high-temperature flue gas emissions during operation, significantly improving the production environment and enhancing the environmental friendliness and operational safety of the process.

[0101] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A magnesium smelting furnace, characterized in that: include: Furnace body, reaction vessel and electric heating elements; The furnace body has a furnace cavity, in which at least one reaction container is placed; the reaction container has a reaction chamber, and the reaction chamber is an annular cavity structure; The reaction container comprises: an outer cylinder and an inner cylinder coaxially nested; At least one circumferentially arranged electric heating element is respectively provided on the outer side of the outer cylinder and the inner side of the inner cylinder.

2. The magnesium smelting furnace according to claim 1, characterized in that: The reaction chamber is formed between the inner side wall of the outer cylinder and the outer side wall of the inner cylinder; at least one circumferentially arranged electric heating element is respectively provided on the outer side wall of the outer cylinder and the inner side wall of the inner cylinder.

3. The magnesium smelting furnace according to claim 1, characterized in that: The plurality of electric heating elements located on the outer side of the outer cylinder and the inner side of the inner cylinder are distributed in a circumferential array.

4. The magnesium smelting furnace according to claim 1, characterized in that: The reaction vessel further comprises: a feeding component and a slag discharge component; The feeding component includes: an upper cover and a first pipe; the upper cover is arranged on the top of the outer cylinder and the inner cylinder; the upper cover has a feeding inlet, and the feeding inlet is connected to the reaction chamber through the first pipe; The slag discharge component includes: a lower cover and a second pipe; the lower cover is arranged at the bottom of the outer cylinder and the inner cylinder; the lower cover has a slag discharge outlet, and the slag discharge outlet is connected to the reaction chamber through the second pipe.

5. The magnesium smelting furnace according to any one of claims 1 to 4, characterized in that: Also includes: a magnesium crystallization device disposed outside the furnace body; The magnesium crystallization device comprises: a crystallization chamber, a cooling device and a third pipeline; The crystallization chamber is communicated with the reaction chamber through the third pipe; the cooling device is arranged on the third pipe or outside the crystallization chamber.

6. The magnesium smelting furnace according to any one of claims 1 to 4, characterized in that: The furnace body includes: an outer shell layer, an insulation layer and a refractory layer; the refractory layer is arranged around the outside of the reaction container; the electric heating element located outside the outer cylinder is placed between the outer cylinder and the refractory layer; the insulation layer is placed between the outer shell layer and the refractory layer.

7. The magnesium smelting furnace according to claim 1, characterized in that: A first gap is set between the outer side wall of the outer cylinder and the corresponding electric heating element, and a second gap is set between the inner side wall of the inner cylinder and the corresponding electric heating element. The gap distance of the first gap and the gap distance of the second gap are both between 1mm and 20mm.

8. The magnesium smelting furnace according to claim 1, characterized in that: The ratio of the radius of the inner cylinder to the radius of the outer cylinder is in a range of 20% to 80%.

9. The magnesium smelting furnace according to claim 1, characterized in that: The annular width of the reaction chamber is 80 mm to 300 mm.

10. A magnesium smelting method, characterized in that: The magnesium smelting furnace according to any one of claims 1 to 9, wherein the magnesium smelting furnace further comprises: a magnesium crystallization device disposed outside the furnace body; the magnesium crystallization device comprises: a crystallization chamber, a cooling device, and a third pipe; the crystallization chamber is connected to the reaction chamber through the third pipe; the cooling device is disposed on the third pipe or outside the crystallization chamber; The method comprises: Adding magnesium smelting raw material balls into the reaction chamber; The electric heating elements on the outer side of the outer cylinder and the inner side of the inner cylinder are controlled to heat the raw material balls in the reaction chamber, so that the raw material balls in the reaction chamber undergo a reduction reaction to produce magnesium vapor; wherein the temperature of the outer cylinder wall is controlled to be 1200° C.±25° C., and the time required to complete the reduction process is 4 hours to 6 hours; The magnesium vapor enters the crystallization chamber through the third pipe, and the temperature in the crystallization chamber is controlled by the cooling device to be cooled to 450° C. to 550° C. to crystallize and produce crude magnesium; The crude magnesium is taken out and subjected to a post-demagnesium process.

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