Special-shaped energy-saving smelting device and metal smelting method

Abstract

The invention discloses a special-shaped energy-saving smelting device and a metal smelting method. The special-shaped energy-saving smelting device comprises a smelting container, the smelting container is internally provided with a smelting cavity, the cavity bottom of the smelting cavity is provided with at least one protruding structure, and the interior of the protruding structure is of a cavity structure with the bottom open; a first heating mechanism, a second heating mechanism and a lifting mechanism, the first heating mechanism is fixedly arranged on the outer side of the smelting container in the radial direction of the smelting container and is in heat conduction fit with the smelting container, and the second heating mechanism is movably arranged in the cavity structure and is further in transmission connection with the lifting mechanism; and the lifting mechanism can lift along the depth direction of the cavity structure under the driving of the lifting mechanism. According to the special-shaped energy-saving smelting device, the heating area is larger, the structural strength and rigidity are higher, the deformation risk is reduced, and by means of the special-shaped energy-saving smelting device, the smelting time can be shortened to 3 hours.

Description

Technical Field

[0001] The present invention particularly relates to a special-shaped energy-saving smelting device and a method for smelting metal, and belongs to the technical field of metal smelting equipment. Background Art

[0002] In the field of metal smelting and processing, magnesium and aluminum alloys are widely used in key industries such as aerospace, automotive manufacturing, and electronic communications due to their excellent mechanical properties, lightweight characteristics, and good machinability. The melting process of magnesium and aluminum alloys, as the core link in their smelting and subsequent processing (such as casting and die-casting), directly affects melt quality, production efficiency, and energy consumption.

[0003] In existing technology, crucibles used to melt magnesium and aluminum alloys are key equipment for achieving metal melting. Their structural design and heating method play a decisive role in the melting effect. Traditional crucibles for melting magnesium and aluminum alloys are mainly divided into two types: round crucibles and trough crucibles. These two crucible structures are widely used in small and medium-sized melting scenarios due to their simple structure, mature manufacturing process, and relatively low cost.

[0004] Both of these traditional crucible heating methods utilize external heat radiation, which is then transferred through the crucible walls to the metal material inside, melting the metal. For smaller crucibles (e.g., under 100 kg), the heat generated by external radiation heating can be quickly transferred to the metal interior due to the small amount of metal material and its low heat capacity, resulting in a heating rate that meets production requirements.

[0005] However, with the increasing demand for magnesium and aluminum alloys in industrial production, the use of large-capacity crucibles (e.g., over 500 kg) has become increasingly widespread, and the limitations of traditional crucible structures and heating methods have become increasingly prominent. Specifically, with large crucibles, due to the large amount of metal material accumulated and the long heat conduction path, the heat from external radiation heating has difficulty quickly and evenly penetrating the metal material deep inside the crucible, resulting in a significantly longer overall heating and melting time, often exceeding 6 hours.

[0006] The long heating process not only significantly reduces production efficiency and increases energy consumption per unit product, but more seriously, magnesium and aluminum, as metals with relatively active chemical properties, will react violently with oxygen in the air when exposed to the melting environment at high temperature for a long time (even under a protective atmosphere, there is still a certain risk of oxidation), resulting in severe oxidation of the melt and the generation of a large number of oxide inclusions. These oxide inclusions will directly affect the mechanical properties (such as strength and toughness) and surface quality of subsequent castings, increasing the product scrap rate; at the same time, severe oxidation may also cause the melt composition to deviate from the design requirements, further reducing the stability of material properties. Therefore, the problems of long heating time and severe melt oxidation in traditional round and trough crucibles during the melting of large-capacity magnesium and aluminum alloys have become the key bottleneck restricting the efficient and high-quality melting of large-capacity magnesium and aluminum alloys. A new crucible structure that can solve the above-mentioned defects is urgently needed. Summary of the Invention

[0007] In response to the problems of slow melting speed and low energy efficiency of existing crucibles for magnesium-aluminum alloys, the main purpose of the present invention is to provide a special-shaped energy-saving melting device and a method for melting metal, which can improve the melting efficiency and reduce the oxidation problem of the melt caused by long-term heating, thereby overcoming the shortcomings of the existing technology.

[0008] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0009] A first aspect of an embodiment of the present invention provides a special-shaped energy-saving smelting device, comprising:

[0010] A smelting container, wherein the smelting container has a smelting cavity therein, the center area of ​​the bottom of the smelting cavity has a protruding structure, and the interior of the protruding structure is a hollow structure with an open bottom;

[0011] A first heating mechanism, a second heating mechanism and a lifting mechanism, wherein the first heating mechanism is fixedly arranged on the outer side of the smelting container along the radial direction of the smelting container and cooperates with the smelting container for heat conduction, and the second heating mechanism is movably arranged in the cavity structure, and the second heating mechanism is also transmission-connected to the lifting mechanism and can be lifted and lowered along the depth direction of the cavity structure under the drive of the lifting mechanism. By changing the depth position of the second heating mechanism in the cavity structure, the convection flow rate in the melt located in the smelting cavity can be changed.

[0012] A second aspect of an embodiment of the present invention provides a method for smelting metal, comprising:

[0013] Providing the special-shaped energy-saving smelting device;

[0014] placing the metal material to be smelted in the smelting chamber;

[0015] At the same time, the first heating mechanism and the second heating mechanism are used to heat the metal material located in the smelting chamber and melt the metal material to form a melt. In addition, the lifting mechanism drives the second heating mechanism to move up and down along the depth direction of the cavity structure to change the convection flow rate in the melt located in the smelting chamber.

[0016] Compared with the prior art, the advantages of the present invention include:

[0017] The embodiment of the present invention provides a special-shaped energy-saving melting device with a larger heating area, higher structural strength and rigidity, and reduced deformation risk. By using the special-shaped energy-saving melting device of the present invention, the melting time can be shortened to 3 hours (500Kg).

[0018] An embodiment of the present invention provides a special-shaped energy-saving smelting device with a smelting chamber having a bulge in the middle, and a cavity structure is formed within the bulge structure. At the same time, a heating mechanism is added inside the cavity structure for heating. In this way, the inside and outside of the smelting container are heated simultaneously, thereby increasing the heating area of ​​the smelting container and accelerating the melting of the alloy. The heating area is increased by 25% compared with traditional crucibles, and the melting time is shortened by 35%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 、 Figure 2 It is a structural schematic diagram of a special-shaped energy-saving smelting device provided in a typical embodiment of the present invention;

[0020] Figure 3 is the temperature distribution of the melt in a traditional crucible;

[0021] Figure 4 The present invention provides a typical embodiment of the temperature distribution of the melt inside a special-shaped energy-saving crucible. DETAILED DESCRIPTION

[0022] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The following will further explain this technical solution, its implementation process and principles.

[0023] A first aspect of an embodiment of the present invention provides a special-shaped energy-saving smelting device, comprising:

[0024] A smelting container, wherein the smelting container has a smelting cavity therein, the center area of ​​the bottom of the smelting cavity has a protruding structure, and the interior of the protruding structure is a hollow structure with an open bottom;

[0025] A first heating mechanism, a second heating mechanism and a lifting mechanism, wherein the first heating mechanism is fixedly arranged on the outer side of the smelting container along the radial direction of the smelting container and cooperates with the smelting container for heat conduction, and the second heating mechanism is movably arranged in the cavity structure, and the second heating mechanism is also transmission-connected to the lifting mechanism and can be lifted and lowered along the depth direction of the cavity structure under the drive of the lifting mechanism. By changing the depth position of the second heating mechanism in the cavity structure, the convection flow rate in the melt located in the smelting cavity can be changed.

[0026] Furthermore, the protruding direction of the protruding structure is parallel to the axial direction of the smelting cavity and the depth direction of the cavity structure. The height h of the protruding structure is (1 / 3 to 3 / 4)H, where H is the height of the smelting cavity.

[0027] Furthermore, the central axis of the protruding structure coincides with the central axis of the smelting chamber.

[0028] Furthermore, the surface of the protruding structure is smoothly connected to the bottom of the smelting chamber, the top surface of the protruding structure is a curved surface protruding upward along the axial direction of the smelting chamber, and the bottom of the smelting chamber is a curved surface concave downward along the axial direction of the smelting chamber.

[0029] Furthermore, the first heating mechanism is a cylindrical structure sleeved outside the smelting container, and the second heating mechanism is a cylindrical structure sleeved inside the cavity structure. Both the first heating mechanism and the second heating mechanism are in thermal contact with the smelting container.

[0030] Furthermore, the first heating mechanism is an electroheating mechanism.

[0031] Furthermore, the first heating mechanism is a conductive coil.

[0032] Furthermore, the second heating mechanism is an electrothermal mechanism, and the second heating mechanism is a conductive coil.

[0033] It should be noted that the heating power of the first heating mechanism and the second heating mechanism can be adjusted independently.

[0034] Furthermore, the smelting container includes a container shell, the container shell encloses the smelting chamber, and a bottom portion of the container shell protrudes upward along the axial direction of the smelting container to form the protruding structure.

[0035] Furthermore, the interior of the container shell is a hollow interlayer cavity, and the container shell is also provided with an air inlet and an air outlet, and the special-shaped energy-saving smelting device also includes an airflow cooling mechanism, which is connected to the air inlet and is used to input cooling gas into the interlayer cavity. The cooling gas enters from the air inlet and is output from the air outlet, and forms a gas vortex in the interlayer cavity that flows around the smelting cavity.

[0036] Furthermore, the air inlet is arranged in the bottom area of ​​the smelting container, and the air outlet is arranged in the top area of ​​the smelting container.

[0037] Furthermore, the air inlet and the air outlet are arranged at diagonal positions of the smelting container.

[0038] Furthermore, the smelting container further includes a heat-insulating structure, and the heat-insulating structure is wrapped around the outside of the container shell.

[0039] Furthermore, the second heating mechanism is fixedly arranged on a supporting body, and the supporting body is transmission-connected to the lifting mechanism.

[0040] Furthermore, the support body includes a base portion and a support portion, the support portion is fixedly arranged on the base portion, the support portion is movably arranged in the cavity structure, the second heating mechanism is fixedly arranged on the support portion, and the lifting mechanism is connected to the base portion.

[0041] A second aspect of an embodiment of the present invention provides a method for smelting metal, comprising:

[0042] Providing the special-shaped energy-saving smelting device;

[0043] placing the metal material to be smelted in the smelting chamber;

[0044] At the same time, the first heating mechanism and the second heating mechanism are used to heat the metal material located in the smelting chamber and melt the metal material to form a melt. In addition, the lifting mechanism drives the second heating mechanism to move up and down along the depth direction of the cavity structure to change the convection flow rate in the melt located in the smelting chamber.

[0045] In a more specific embodiment, the method for smelting metal further comprises: adjusting the heating power of the first heating mechanism and / or the second heating mechanism to change the convection flow rate in the melt in the smelting chamber.

[0046] In a more specific embodiment, the metal smelting method further includes: after melting the metal material to form a melt, introducing a cooling gas into an interlayer cavity within the vessel shell of the smelting vessel, wherein the cooling gas enters from a bottom area of ​​the smelting vessel and exits from a top area of ​​the smelting vessel, and the cooling gas forms a gas vortex in the interlayer cavity that flows around the smelting cavity.

[0047] The following will further explain the technical solution, its implementation process and principles with reference to the accompanying drawings and specific implementation cases.

[0048] In a typical implementation, see Figure 1 and Figure 2 A special-shaped energy-saving smelting device includes a smelting container 100, a first heating mechanism 210, a second heating mechanism 220 and a lifting mechanism 230. The smelting container 100 has a smelting cavity 110 inside. The center area of ​​the bottom of the smelting cavity 110 has a protruding structure 120. The interior of the protruding structure 120 is a hollow structure with an open bottom. The first heating mechanism 210 is fixedly arranged on the outside of the smelting container 100 along the radial direction of the smelting container 100 and cooperates with the smelting container 100 for heat conduction. The second heating mechanism 220 is movably arranged in the hollow structure, and The second heating mechanism 220 is also transmission-connected to the lifting mechanism 230, and can be lifted and lowered along the depth direction of the cavity structure under the drive of the lifting mechanism 230. The depth position of the second heating mechanism 220 in the cavity structure is adjustable. It can be understood that by changing the depth position of the second heating mechanism 220 in the cavity structure, the effective heating area of ​​the second heating mechanism 220 and the distance between the second heating mechanism 220 and the cavity structure in the depth direction can be changed, thereby changing the heating efficiency of the second heating mechanism 220, so that the convection flow rate in the melt in the smelting chamber changes accordingly.

[0049] Specifically, after the metal material is completely melted to form a melt, in order to ensure that the chemical composition of the melt is uniform, the second heating mechanism 220 is driven by the lifting mechanism 230 to move up and down along the depth direction of the cavity structure. The heating efficiency of the second heating mechanism 220 can be changed, and the temperature difference between the melt near the outer area of ​​the first heating mechanism 210 and the inner area near the second heating mechanism 220 changes, and the convection flow rate in the melt in the smelting chamber changes accordingly, thereby redistributing the components in the melt and reducing segregation.

[0050] Specifically, in the initial stage of melting, heat is radiated to the smelting container through the first heating mechanism and the second heating mechanism to melt the metal material. When the first heating mechanism and the second heating mechanism continue to heat, the melt close to the wall of the smelting container transfers heat to the internal melt through convection. When the melt temperature is uniform, the second heating mechanism located inside is moved downward to reduce the convection speed and its heating power to save electricity.

[0051] It can be understood that the first heating mechanism 210 and the second heating mechanism 220 transfer heat to the metal raw material / melt through the smelting container 100. By providing the protruding structure 120 on the bottom of the smelting chamber 110, the surface area of ​​the interior of the smelting chamber 110 can be increased, that is, the contact area between the metal raw material / melt and the smelting container 100 is increased, thereby improving the heating efficiency of the special-shaped energy-saving smelting device. By providing the protruding structure 120, the heated area can be increased by at least 25%.

[0052] Specifically, the protruding direction of the protruding structure 120 is parallel to the axial direction of the smelting chamber 110 and the depth direction of the cavity structure. More specifically, the central axis of the protruding structure 120 coincides with the central axis of the smelting chamber 110, that is, in the radial direction, the protruding structure 120 is located in the central area of ​​the smelting chamber 110, and in the axial direction, the height h of the protruding structure 120 is (1 / 3 to 3 / 4)H, where H is the height of the smelting chamber 110. Through such a design, the convection effect of the melt in the smelting chamber 110 can be improved, thereby affecting the heating rate and temperature uniformity of the melt.

[0053] For details, please refer to Figure 1 and Figure 2 The smelting vessel 100 includes a container shell 130, which encloses and forms the smelting chamber 110. A portion of the bottom of the container shell 130 protrudes upward along the axial direction of the smelting vessel 100 to form the protruding structure 120. It is understood that the container shell 130 can be an integrally cast structure. The container shell 130 is a special-shaped structure. The special-shaped structure here primarily refers to a special-shaped bottom. Specifically, a portion of the bottom protrudes / bends upward along the axial direction of the smelting vessel 100 to form the protruding structure 120. Specifically, the container shell 130 is a shell with good thermal conductivity, such as a stainless steel shell, a low-carbon steel shell, or a cast steel shell. It should be noted that the smelting vessel 100 may also include a container lid that can be opened and closed.

[0054] More specifically, the surface of the raised structure 120 smoothly connects to the bottom of the smelting chamber 110. The top surface of the raised structure 120 is a curved surface that convexly projects upward along the axial direction of the smelting chamber 110, while the bottom of the smelting chamber 110 is a curved surface that concavely projects downward along the axial direction of the smelting chamber 110. Exemplarily, the radius of curvature R of these curved surface structures is greater than 50 mm. This design not only increases the surface area of ​​the inner wall of the smelting chamber 110 but also makes the temperature distribution of the melt within the smelting chamber 110 more uniform. Furthermore, the curved surface creates a smoothly transitioned inner wall structure for the smelting chamber 110, reducing the convective resistance of the melt, reducing stress, and improving service life.

[0055] Specifically, the first heating mechanism 210 is a cylindrical structure mounted on the exterior of the smelting vessel 100, and the second heating mechanism 220 is a cylindrical structure mounted within the cavity structure. Both the first heating mechanism 210 and the second heating mechanism 220 are in thermal contact with the smelting vessel 100. More specifically, both the first heating mechanism 210 and the second heating mechanism 220 are electrothermal mechanisms. For example, both the first heating mechanism 210 and the second heating mechanism 220 are conductive coils. By connecting the first heating mechanism 210 and the second heating mechanism 220 to a power source, heat is generated through the thermal effect of the current, thereby heating the smelting vessel 100. It should be noted that to avoid connecting the smelting vessel 100 to a power source, the surface area of ​​the smelting vessel 100 in contact with the first heating mechanism 210 and the second heating mechanism 220 may be provided with an insulating thermally conductive layer, such as an aluminum oxide layer.

[0056] Specifically, the lifting mechanism 230 can be directly connected to the second heating mechanism 220. As those skilled in the art can easily imagine, since the second heating mechanism 220 is an electrothermal mechanism, the second heating mechanism 220 and the lifting mechanism 230 are insulated. For example, an insulating structure (such as an insulating pad, etc.) is provided between the second heating mechanism 220 and the lifting mechanism 230. While the second heating mechanism 220 can be driven to rise and fall by the lifting mechanism 230, the second heating mechanism 220 and the lifting mechanism 230 are prevented from conducting electricity. These are all well known and easy to imagine in the art and are not limited too much here. Exemplarily, the lifting mechanism 230 can be a linear drive motor, a linear drive cylinder, a linear drive oil cylinder, etc.

[0057] In a more typical implementation, please refer again to Figure 1 and Figure 2The second heating mechanism can be fixedly mounted on a support body 400, and the support body 400 is transmission-connected to the lifting mechanism 230. The support body 400 is an insulator, for example, the support body 400 can be a ceramic component. More specifically, the support body 400 includes a base portion 410 and a support portion 420. The support portion 420 is fixedly mounted on the base portion 410, and the support portion 420 is movably mounted within the cavity structure. The second heating mechanism is fixedly mounted on the support portion 420, and the lifting mechanism 230 is connected to the base portion 410. Specifically, the radial cross-sectional area of ​​the support portion 420 is smaller than the radial cross-sectional area of ​​the base portion 410, and the contour shape of the support portion 420 is the same as / similar to the cavity structure inside the protruding structure 120. The radial cross-sectional area of ​​the support portion 420 is smaller than the radial cross-sectional area of ​​the cavity structure, so that the support portion 420 and the second heating mechanism 220 fixed on the support portion 420 can move up and down within the cavity structure. The radial cross-sectional area of ​​the base portion 410 is larger than the radial cross-sectional area of ​​the cavity structure. For example, the radial cross-sectional area of ​​the base portion 410 may be close to the radial cross-sectional area of ​​the entire smelting vessel 100 .

[0058] In a more specific implementation, please refer again to Figure 1 and Figure 2 The smelting vessel 100 further includes a heat-insulating structure 140, which is wrapped around the exterior of the vessel shell 130. It is understood that the first heating mechanism 210 is located between the heat-insulating structure 140 and the vessel shell 130. It is understood that the heat-insulating structure 140 is also insulating. For example, the heat-insulating structure 140 may be a calcium silicate insulation jacket, or the like.

[0059] Specifically, when a conductive coil is used as the first heating mechanism and the second heating mechanism, a spiral positioning groove may be provided on the outer circumferential surface of the support body 400, and the conductive coil serving as the first heating mechanism can be fixed in the positioning groove on the support body to achieve positioning and fixation of the first heating mechanism. At the same time, a spiral positioning groove is also provided on the outer circumferential surface of the container shell 130 of the smelting vessel 100, and the conductive coil serving as the second heating mechanism can be fixed in the positioning groove on the container shell 130 to achieve positioning and fixation of the second heating mechanism. Of course, the positioning groove for fixing the second heating mechanism can also be provided on the side surface of the thermal insulation structure facing the container shell 130.

[0060] In a more specific implementation, please refer again to Figure 1 and Figure 2The interior of the container shell 130 is a hollow interlayer cavity 131. The container shell 130 is also provided with an air inlet 132 and an air outlet 133. The special-shaped energy-saving smelting device also includes an airflow cooling mechanism, which is connected to the air inlet 132 and is used to input cooling gas into the interlayer cavity 131. The cooling gas enters from the air inlet 132 and is output from the air outlet 133, forming a gas vortex flowing around the smelting cavity 110 in the interlayer cavity 131 to meet the requirement of rapid cooling of the melt. It should be noted that the airflow cooling mechanism can be a mechanism known in the art that can achieve other cooling supplies, and its specific structure and equipment model are not limited here.

[0061] Specifically, the air inlet 132 is provided at the bottom area of ​​the smelting container 100 , and the air outlet 133 is provided at the top area of ​​the smelting container 100 . Preferably, the air inlet 132 and the air outlet 133 are provided at diagonal positions of the smelting container 100 .

[0062] Specifically, the smelting vessel 100 may be a crucible. When the smelting vessel 100 is a crucible for melting magnesium alloys, the vessel shell 130 is preferably made of a composite steel plate. For example, the outer shell of the vessel shell 130 is made of stainless steel, and the inner shell is made of low-carbon steel. When the smelting vessel 100 is a crucible for melting aluminum alloys, both the inner and outer shells of the vessel shell 130 are made of cast steel. More specifically, a retaining ring is provided on the top of the smelting vessel 100. The retaining ring surrounds the periphery of the top opening of the smelting vessel 100 and extends radially outward from the smelting vessel 100. More specifically, the retaining ring may cover the top of the insulation structure. The retaining ring is an insulating structure, such as a rubber ring, and is primarily used to prevent the smelting vessel 100 from contacting conductive structures within the melting furnace when placed within the furnace, thereby preventing electric shock.

[0063] In a more specific embodiment, using Figure 1 and Figure 2 The method for smelting metal using the special-shaped energy-saving smelting device shown includes:

[0064] When melting begins, the lifting mechanism 230 drives the second heating mechanism 220 to the highest position in the cavity structure, and the first heating mechanism 210 and the second heating mechanism 220 are heated simultaneously. When the metal material in the smelting chamber 110 is completely melted, in order to ensure the uniform chemical composition of the melt, the lifting mechanism 230 is used to move the second heating mechanism 220 at the bottom up and down, thereby changing the convection speed in the melt, thereby redistributing the components in the melt and reducing segregation. When pouring is ready, the lifting mechanism 230 is lowered and the power is turned off (to save electricity). In addition, the heating power of the first heating mechanism and / or the second heating mechanism can be adjusted to change the convection flow rate in the melt in the smelting chamber.

[0065] For alloys that require rapid cooling, the smelting chamber 110 and the heating power supply are closed at this time, and compressed air is introduced into the container shell 130 of the smelting container 100, entering from the bottom vent and being released from the upper air outlet 133 to form a swirling gas to ensure rapid cooling.

[0066] A 200 kg conventional crucible and a crucible of the present invention were used to conduct a casting test, with magnesium alloy as the test object. By comparing the conventional crucible without the hollow protrusion structure 120 in the melting chamber 110 and the crucible using the structure of the present invention, the temperature distribution of the melt inside the conventional crucible is shown as follows: Figure 3 As shown, the temperature distribution of the melt inside the crucible of the present invention is as follows Figure 4 As shown, it is obvious that the temperature distribution of the melt inside the crucible of the present invention is more uniform and has lower dispersion, and the melting time of the crucible of the present invention is reduced by 35% compared with the traditional crucible.

[0067] The embodiment of the present invention provides a special-shaped energy-saving melting device with a larger heating area, higher structural strength and rigidity, and reduced deformation risk. By using the special-shaped energy-saving melting device of the present invention, the melting time can be shortened to 3 hours (500Kg).

[0068] An embodiment of the present invention provides a special-shaped energy-saving smelting device with a smelting chamber having a bulge in the middle, and a cavity structure is formed within the bulge structure. At the same time, a heating mechanism is added inside the cavity structure for heating. In this way, the inside and outside of the smelting container are heated simultaneously, thereby increasing the heating area of ​​the smelting container and accelerating the melting of the alloy. The heating area is increased by 25% compared with traditional crucibles, and the melting time is shortened by 35%.

[0069] It should be understood that the above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A special-shaped energy-saving smelting device, characterized in that: include: A smelting container, wherein the smelting container has a smelting cavity therein, the center area of ​​the bottom of the smelting cavity has a protruding structure, and the interior of the protruding structure is a hollow structure with an open bottom; A first heating mechanism, a second heating mechanism and a lifting mechanism, wherein the first heating mechanism is fixedly arranged on the outer side of the smelting container along the radial direction of the smelting container and cooperates with the smelting container for heat conduction, and the second heating mechanism is movably arranged in the cavity structure, and the second heating mechanism is also transmission-connected to the lifting mechanism and can be lifted and lowered along the longitudinal direction of the cavity structure under the drive of the lifting mechanism. By changing the longitudinal position of the second heating mechanism in the cavity structure, the convection flow rate in the melt in the smelting cavity can be changed.

2. The special-shaped energy-saving smelting device according to claim 1, characterized in that: The protruding direction of the protruding structure is parallel to the axial direction of the smelting cavity and the depth direction of the cavity structure. The height h of the protruding structure is (1 / 3 to 3 / 4) H, where H is the height of the smelting cavity. Preferably, the central axis of the protruding structure coincides with the central axis of the smelting chamber.

3. The special-shaped energy-saving smelting device according to claim 1, characterized in that: The surface of the protruding structure is smoothly connected to the bottom of the smelting chamber. The top surface of the protruding structure is a curved surface protruding upward along the axial direction of the smelting chamber, and the bottom of the smelting chamber is a curved surface concave downward along the axial direction of the smelting chamber.

4. The special-shaped energy-saving smelting device according to claim 1 or 2, characterized in that: The first heating mechanism is a cylindrical structure sleeved outside the smelting container, and the second heating mechanism is a cylindrical structure sleeved inside the cavity structure. Both the first heating mechanism and the second heating mechanism are in thermal contact with the smelting container.

5. The special-shaped energy-saving smelting device according to claim 4, characterized in that: The first heating mechanism is an electrothermal mechanism; preferably, the first heating mechanism is a conductive coil; And / or, the second heating mechanism is an electrothermal mechanism, and the second heating mechanism is a conductive coil.

6. The special-shaped energy-saving smelting device according to claim 1, characterized in that: The smelting container includes a container shell, which encloses the smelting chamber. A portion of the bottom of the container shell protrudes upward along the axial direction of the smelting container to form the protruding structure.

7. The special-shaped energy-saving smelting device according to claim 6, characterized in that: The interior of the container shell is a hollow interlayer cavity, and the container shell is also provided with an air inlet and an air outlet. The special-shaped energy-saving smelting device also includes an airflow cooling mechanism, which is connected to the air inlet and is used to input cooling gas into the interlayer cavity. The cooling gas enters from the air inlet and is output from the air outlet, and forms a gas vortex in the interlayer cavity that flows around the smelting cavity. Preferably, the air inlet is arranged in the bottom area of ​​the smelting container, and the air outlet is arranged in the top area of ​​the smelting container; Preferably, the air inlet and the air outlet are arranged at diagonal positions of the smelting container; And / or, the smelting container further includes a heat-insulating structure, and the heat-insulating structure is wrapped around the outside of the container shell.

8. The special-shaped energy-saving smelting device according to claim 1, characterized in that: The second heating mechanism is fixedly mounted on a support body, and the support body is in transmission connection with the lifting mechanism; Preferably, the support body includes a base portion and a support portion, the support portion is fixedly arranged on the base portion, the support portion is movably arranged in the cavity structure, the second heating mechanism is fixedly arranged on the support portion, and the lifting mechanism is connected to the base portion.

9. A method for smelting metal, characterized in that: include: Provide a special-shaped energy-saving melting device according to any one of claims 1 to 8; placing the metal material to be smelted in the smelting chamber; At the same time, the first heating mechanism and the second heating mechanism are used to heat the metal material located in the smelting chamber and melt the metal material to form a melt. In addition, the lifting mechanism drives the second heating mechanism to move up and down along the depth direction of the cavity structure to change the convection flow rate in the melt located in the smelting chamber.

10. The method for smelting metal according to claim 9, characterized in that: Also includes: adjusting the heating power of the first heating mechanism and / or the second heating mechanism to change the convection flow rate of the melt in the smelting chamber; And / or, the metal smelting method is characterized by further comprising: After the metal material is melted to form a melt, cooling gas is introduced into the interlayer cavity within the vessel shell of the smelting vessel. The cooling gas enters from the bottom area of ​​the smelting vessel and is discharged from the top area of ​​the smelting vessel. The cooling gas forms a gas vortex in the interlayer cavity that flows around the smelting cavity.

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