Electric heating oxygen-free circulating smelting holding furnace

Abstract

The utility model provides a kind of electric heating oxygen-free circulating smelting heat preservation furnace, including smelting heat preservation furnace, the smelting heat preservation furnace includes melting chamber and heat preservation chamber, heat preservation chamber is located in the lower side of melting chamber, and melting chamber and heat preservation chamber are communicated. Waste heat recovery heating system is connected between melting chamber and heat preservation chamber, and waste heat recovery heating system extracts hot gas in melting chamber, and inputs into melting heat preservation chamber after heating hot gas. Waste heat recovery heating system includes electric heating mechanism, electric heating mechanism is communicated by suction duct and melting chamber, and electric heating mechanism is connected by air supply pipe and melting and heat preservation chamber, and suction duct is equipped with suction fan, and suction fan extracts hot gas in melting chamber and sends into electric heating mechanism. The utility model utilizes melting chamber waste heat to heat melting and heat preservation chamber, so that heat preservation chamber is maintained in appropriate temperature range, and energy consumption and production cost are reduced.

Description

Technical Field

[0001] This utility model belongs to the field of non-ferrous metal melting, high pressure, low pressure, gravity, differential pressure and other casting technology, and specifically relates to an electrically heated oxygen-free circulating melting and holding furnace. Background Technology

[0002] With the green transformation and upgrading of China's manufacturing industry and the requirements for intelligent and sustainable development, how to improve the intelligent level of the casting industry, reduce carbon emissions, reduce energy consumption, and reduce dependence on traditional petrochemical energy has become a hot and urgent issue that needs to be addressed. According to relevant industry statistics, smelting and holding furnaces in the non-ferrous metal casting industry are major energy consumers in foundries and are traditionally labor-intensive jobs, accounting for more than 50% of the energy consumption of the entire plant's smelting and holding processes. Currently, smelting and holding furnaces used in foundries widely employ petrochemical fuel combustion as their energy source and are aerobic systems. They generate flames through fuel combustion (such as LPG and LNG), utilizing the heat radiation of the flames to melt and hold non-ferrous alloys. Less than 40% of the heat generated during fuel combustion is used to heat the alloy, while the remaining 60% or more is emitted into the atmosphere as exhaust gas, causing environmental pollution and increasing the production costs and carbon footprint of casting enterprises. The aerobic system also causes a large amount of alloy oxidation during the smelting and holding process, which greatly increases the cleaning frequency and workload for operators.

[0003] Therefore, the above problems urgently need to be solved. Utility Model Content

[0004] Purpose of the utility model: In order to overcome the above shortcomings, this utility model provides an electrically heated oxygen-free circulating smelting and holding furnace, which uses electric heating to replace traditional fuel combustion, improves temperature controllability, improves energy conversion rate, reduces energy waste, eliminates waste gas emissions, and improves environmental protection; it also recovers waste heat, reduces the energy consumption of the smelting and holding furnace, and reduces production costs.

[0005] Technical Solution: To achieve the above objectives, this utility model provides an electrically heated oxygen-free circulating melting and holding furnace, comprising a melting and holding furnace, wherein the melting and holding furnace includes a melting chamber and a holding chamber, the holding chamber being located below the melting chamber and connected to it. A waste heat recovery heating system is connected between the melting chamber and the holding chamber, the waste heat recovery heating system extracting hot gas from the melting chamber, heating the hot gas, and then inputting it into the melting chamber and the holding chamber. The waste heat recovery heating system includes an electric heating mechanism, which is connected to the melting chamber via an exhaust pipe and to the melting chamber and the holding chamber via an air supply pipe. The exhaust pipe is equipped with an exhaust fan, which extracts hot gas from the melting chamber and sends it into the electric heating mechanism. The electric heating mechanism is a gas heater, including fins and electric heating tubes passing through the fins, which convert electrical energy into heat energy, thereby heating the system gas. In this invention, the melting chamber melts the metal, and the molten metal flows into the heat-preserving chamber under gravity. The heat-preserving chamber is equipped with a temperature detection mechanism (such as a thermocouple). When the temperature detection mechanism detects a decrease in the temperature inside the heat-preserving chamber, an exhaust fan is activated. The exhaust fan draws hot air from the heat-preserving chamber and sends it through an air supply pipe into the melting chamber and the heat-preserving chamber. The air supply pipe is also equipped with a temperature detection mechanism (such as a thermocouple). If the temperature detected at the air supply pipe is low, an electric heating mechanism is activated to heat the gas, ensuring that the temperature entering the heat-preserving chamber reaches the set value. This invention utilizes the residual heat of the melting chamber to preheat both the melting chamber and the heat-preserving chamber, maintaining the heat-preserving chamber within a suitable temperature range, thus reducing energy consumption and production costs.

[0006] Furthermore, in the aforementioned electrically heated oxygen-free circulating melting and holding furnace, the electric heating mechanism is equipped with an inert gas storage tank. This tank is connected to an exhaust pipe via a pipeline, and a solenoid valve is installed at the connection point. When the exhaust fan operates, the solenoid valve opens, allowing the inert gas from the storage tank to enter the lower-pressure exhaust pipe. The exhaust fan mixes the inert gas with hot air and then sends it into the electric heating mechanism, which heats the gas. The gas is then sent into the holding chamber through the exhaust pipe. The gas in the holding chamber, under the influence of the exhaust fan, enters the melting chamber, forming a circulation. A gas pressure sensor is installed inside the holding chamber. When the pressure reaches a set value, the solenoid valve closes; when the pressure falls below the set value, the solenoid valve opens, achieving oxygen-free melting and oxygen-free holding, preventing oxidation of the molten metal, improving the quality of the molten metal, and reducing the frequency and workload of cleaning and maintenance.

[0007] Furthermore, in the above-mentioned electrically heated oxygen-free circulating melting and holding furnace, the side wall of the holding chamber 2 is provided with a first electric heating nozzle 21, the side wall of the melting chamber 1 is provided with a second electric heating nozzle 13, and the air supply pipe 33 is connected to the first electric heating nozzle 21 and the second electric heating nozzle 13 respectively. The air supply pipe 33 blows hot air to the holding chamber 2 and the melting chamber 1 through the first electric heating nozzle 21 and the second electric heating nozzle 13 respectively.

[0008] The first and second electric heating burners 13 are respectively provided with gas channels, and electric heating wires are provided around the gas channels. The first and second electric heating burners 13 are respectively provided with thermocouples. The thermocouples detect the temperature of the gas flowing through the gas channels. If the temperature is lower than the set value, the first and second electric heating burners 13 heat the gas to ensure the temperature of the gas sent into the heat preservation chamber and increase the temperature of the heat preservation chamber.

[0009] Furthermore, in the aforementioned electrically heated oxygen-free circulating melting and holding furnace, the air supply duct is equipped with a blower. The blower delivers the gas heated by the electric heating mechanism from the first electric heating burner into the holding chamber. The blower accelerates the flow of the heated gas from the first electric heating burner into the holding chamber, thereby maintaining the temperature of the holding chamber.

[0010] Furthermore, in the aforementioned electrically heated oxygen-free circulating melting and holding furnace, the melting chamber 1 includes a preheating zone 11 and a melting zone 12. The preheating zone 11 is located above the melting zone 12, and the preheating zone 11 and the melting zone 12 are connected by a conduit. The second electric heating nozzle 13 is located on the side wall of the melting zone 12. The exhaust pipe 32 is connected to the preheating zone 11, and the melting zone 12 is connected to the air supply pipe 33 through the second electric heating nozzle 13. The metal in the preheating zone 11 is preheated by the hot air in the melting zone 12, and the metal enters the melting zone 12 under the action of gravity. The metal is heated and melted by the hot air blown out by the second electric heating nozzle 13.

[0011] To improve recycling efficiency, the scrap metal needs to be crushed. After crushing, the scrap metal is magnetically separated and screened before being sent to the preheating zone. The blower sends hot air into the melting zone and the heat preservation chamber. The metal scraps in the preheating zone are heated and then enter the melting zone under gravity. In the melting zone, they are melted by the second electric heating burner and then flow into the heat preservation chamber for heat preservation.

[0012] Furthermore, in the aforementioned electrically heated oxygen-free circulating melting and holding furnace, a feeding hopper is provided at the top of the preheating zone, and a tiltable baffle connects the preheating zone and the feeding hopper. One side of the tiltable baffle is hinged to the top opening of the preheating zone, and a first driving mechanism is connected to the tiltable baffle, which drives the tiltable baffle to tilt. When the tiltable baffle is in a horizontal position, it separates the preheating zone and the feeding hopper. The first driving mechanism is an electric push rod. During feeding, the tiltable baffle is in a horizontal position, closing the preheating zone opening, and metal scraps are poured into the feeding hopper. Then, the first driving mechanism drives the tiltable baffle to tilt, and the metal scraps in the feeding hopper fall into the preheating zone for preheating and melting. Then, the first driving mechanism drives the tiltable baffle to tilt again, closing the preheating zone opening, awaiting the addition of metal scraps. During the melting process, the tiltable baffle closes the preheating zone, preventing air from entering and causing oxidation of the molten metal, thus improving the quality of the molten metal.

[0013] Furthermore, in the aforementioned electrically heated oxygen-free circulating melting and holding furnace, a hinged, tiltable cover is hinged to the upper opening of the feeding hopper. The tiltable cover is driven by a second driving mechanism, which rotates the tiltable cover. When the tiltable cover is in a horizontal position, it closes the upper opening of the feeding hopper. The second driving mechanism is an electric push rod. When metal scraps are poured into the feeding hopper, the second driving mechanism drives the tiltable cover to close the opening, and then the first driving mechanism drives the tiltable baffle to tilt, allowing the scraps in the feeding hopper to enter the preheating zone. During feeding, the first driving mechanism drives the tiltable baffle to tilt and close the preheating zone, while the second driving mechanism drives the tiltable cover to open the feeding hopper, allowing metal scraps to be poured in, reducing air entry and improving the quality of the molten metal.

[0014] Furthermore, in the aforementioned electrically heated oxygen-free circulating smelting and holding furnace, an electric heating rod is connected inside the holding chamber to assist in heating the molten metal inside the holding chamber. When the air supplied through the air duct cannot maintain the temperature of the holding chamber, the electric heating rod is activated, and the electric heating rod located at the bottom of the holding chamber directly heats the molten metal.

[0015] Furthermore, in the aforementioned electrically heated oxygen-free circulating melting and holding furnace, a pressure reducing valve is installed at the connection point between the inert gas storage tank and the exhaust pipe. The pressure reducing valve lowers the gas pressure inside the inert gas storage tank, maintaining a stable output gas pressure. The pressure reducing valve can maintain the gas pressure in the circulating pipeline, and automatically replenishes inert gas when the gas pressure is insufficient, keeping the holding chamber under low pressure and reducing inert gas loss.

[0016] Furthermore, in the aforementioned electrically heated oxygen-free circulating smelting and holding furnace, a feeding mechanism is provided adjacent to the smelting and holding furnace, and the feeding mechanism is a feeding robot. The feeding mechanism uses its vision recognition system to identify the hopper and the upper opening of the feeding bin, and uses its robotic arm to grab the hopper and move it to the upper opening of the feeding bin to pour in the metal scraps, thus achieving automatic feeding.

[0017] As can be seen from the above technical solution, this utility model has the following beneficial effects: The electric heating oxygen-free circulating melting and holding furnace of this utility model utilizes the residual heat of the melting chamber to heat the holding chamber, maintaining the holding chamber within a suitable temperature range, thus reducing energy consumption and production costs. An inert gas storage tank is installed to achieve oxygen-free melting and oxygen-free holding, preventing oxidation of the molten metal, improving the quality of the molten metal, and reducing the frequency and workload of cleaning and maintenance. A controllable flip-up baffle closes the preheating zone opening, and a controllable flip-up cover closes the upper opening of the feeding hopper, reducing air entry and improving the quality of the molten metal. Using an electric heating system instead of the traditional fuel combustion heating method allows for precise control of the heating temperature, high energy conversion efficiency, reduced waste, and zero exhaust emissions, making it more environmentally friendly. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the structure of the electrically heated oxygen-free circulating melting and holding furnace of this utility model.

[0019] In the diagram: 1. Melting chamber, 11. Preheating zone, 12. Melting zone, 13. Second electric heating burner, 2. Insulation chamber, 21. First electric heating burner, 31. Electric heating mechanism, 32. Exhaust pipe, 33. Air supply pipe, 34. Exhaust fan, 35. Air supply fan, 4. Inert gas storage tank, 41. Pressure reducing valve, 5. Feeding mechanism, 6. Feeding bin, 7. Rotatable baffle, 8. Rotatable cover, 9. Electric heating rod. Detailed Implementation

[0020] Example 1

[0021] like Figure 1 The diagram illustrates an electrically heated oxygen-free circulating melting and holding furnace, comprising a melting and holding furnace, which includes a melting chamber 1 and a holding chamber 2. The holding chamber 2 is located below the melting chamber 1, and the melting chamber 1 and the holding chamber 2 are connected. A waste heat recovery heating system is connected between the melting chamber 1 and the holding chamber 2. The waste heat recovery heating system extracts hot air from the melting chamber 1, heats the hot air, and then inputs it into the melting chamber 1 and the holding chamber 2. The waste heat recovery heating system includes an electric heating mechanism 31, which is connected to the melting chamber 1 via an exhaust pipe 32 and to the melting chamber 1 and the holding chamber 2 via an air supply pipe 33. The exhaust pipe 32 is equipped with an exhaust fan 34, which extracts hot air from the melting chamber 1 and sends it into the electric heating mechanism 31. The electric heating mechanism 31 is an air heater, including fins and electric heating tubes passing through the fins, which convert electrical energy into heat energy to heat the air.

[0022] In this embodiment, the electric heating mechanism 31 is equipped with an inert gas storage tank 4, which is connected to the exhaust pipe 32 via a pipe. An electromagnetic valve is provided at the pipe connecting the inert gas storage tank 4 and the exhaust pipe 32.

[0023] In this embodiment, the side wall of the heat preservation chamber 2 is provided with a first electric heating nozzle 21, and the side wall of the melting chamber 1 is provided with a second electric heating nozzle 13. The air supply pipe 33 is connected to the first electric heating nozzle 21 and the second electric heating nozzle 13 respectively. The air supply pipe 33 blows hot air to the heat preservation chamber 2 and the melting chamber 1 through the first electric heating nozzle 21 and the second electric heating nozzle 13 respectively.

[0024] The first heating burner 21 and the second heating burner 13 are respectively provided with gas channels, and electric heating wires are provided around the gas channels. The first heating burner 21 and the second heating burner 13 are respectively provided with thermocouples. The thermocouples detect the temperature of the gas flowing through the gas channels. If the temperature is lower than the set value, the first heating burner and the second heating burner 13 heat the gas to ensure the temperature of the gas sent into the heat preservation chamber and increase the temperature of the heat preservation chamber.

[0025] In this embodiment, the air supply pipe 33 is equipped with a blower 35, which sends the gas heated by the electric heating mechanism 31 from the first electric heating burner 21 into the heat preservation chamber 2.

[0026] In this embodiment, the melting chamber 1 includes a preheating zone 11 and a melting zone 12. The preheating zone 11 is located above the melting zone 12, and the preheating zone 11 and the melting zone 12 are connected by a conduit. The second electric heating nozzle 13 is located on the side wall of the melting zone 12. The exhaust pipe 32 is connected to the preheating zone 11, and the melting zone 12 is connected to the air supply pipe 33 through the second electric heating nozzle 13. The metal in the preheating zone 11 is preheated by the hot air in the melting zone 12. The metal enters the melting zone 12 under the action of gravity, and the metal is heated and melted by the hot air blown out by the second electric heating nozzle 13.

[0027] To improve recycling efficiency, the scrap metal needs to be crushed. After crushing, the scrap metal is magnetically separated and screened before being sent to the preheating zone. A blower sends hot air into the melting zone and the insulation chamber. The metal scrap in the preheating zone is heated and then enters the melting zone under gravity. In the melting zone, it is melted by the second electric heating burner and then flows into the insulation chamber for heat preservation. The second electric heating burner 13 melts the preheated aluminum material in the melting zone 12. A heating element (including a heating rod and a heating coil) is also provided. The heating coil is arranged around the conduit connecting the preheating zone 11 and the melting zone 12 to heat and melt the metal scrap passing through the conduit. A temperature control system is also included to monitor the temperature of the second electric heating burner and adjust its operating temperature accordingly.

[0028] In this embodiment, a feeding hopper 6 is provided at the top of the preheating zone 11, and a flip-up baffle 7 connects the preheating zone 11 and the feeding hopper 6. One side of the flip-up baffle 7 is hinged to the side wall of the top opening of the preheating zone 11, and the flip-up baffle 7 is driven by a first driving mechanism, which drives the flip-up baffle 7 to flip. When the flip-up baffle 7 is in a horizontal position, it separates the preheating zone 11 and the feeding hopper 6. The first driving mechanism is an electric push rod.

[0029] In this embodiment, a hinged flip-top cover 8 is hinged to the upper opening of the feeding hopper 6. The flip-top cover 8 is driven by a second drive mechanism, which drives the flip-top cover 8 to rotate. When the flip-top cover 8 is in a horizontal position, it closes the upper opening of the feeding hopper 6. The second drive mechanism is an electric push rod. The flip-top cover 8 is provided with a ceramic fiber heat insulation layer.

[0030] In this embodiment, an electric heating rod 9 is connected inside the insulation chamber 2 to assist in heating the molten metal inside the insulation chamber 2. When the air supplied by the air supply pipe 33 is insufficient to maintain the temperature of the insulation chamber 2, the electric heating rod 9 is activated. The electric heating rod 9, located at the bottom of the insulation chamber 2, directly heats the molten metal.

[0031] In this embodiment, a pressure reducing valve 41 is provided at the connection between the inert gas storage tank 4 and the exhaust pipe 32. The pressure reducing valve 41 reduces the gas pressure inside the inert gas storage tank 4 and keeps the output gas pressure stable.

[0032] In this embodiment, a feeding mechanism 5 is provided near the smelting and holding furnace, and the feeding mechanism 5 is a feeding robot.

[0033] The working steps of this utility model include:

[0034] Preheating stage: The first drive mechanism drives the flip-up baffle 7 to a horizontal position, closing the opening of the preheating zone 11. The second drive mechanism drives the flip-up cover 8 to open the opening of the feeding hopper 6, opening the solenoid valve to input inert gas. The inert gas in the inert gas storage tank 4 enters the insulation chamber 2 and the melting zone 12 through the air supply pipe 33, and then enters the preheating zone 11 from the melting zone 12. When the oxygen content detector in the melting zone 12 detects that the oxygen content has dropped to the set value, the solenoid valve closes. Then, the solenoid valve at the connection section between the air supply pipe 33 and the insulation chamber 2 closes, and the solenoid valve at the connection section between the air supply pipe 33 and the melting zone 12 closes. The first electric heating burner 21 in the insulation chamber 2 starts to preheat the insulation chamber 2, and the second electric heating burner 13 in the melting zone 12 starts to preheat the melting zone 12. When the temperature reaches the set value, the first electric heating burner 21 closes, completing the preheating process.

[0035] During the feeding stage, the feeding mechanism 5, through its visual recognition system, identifies the hopper and the upper opening of the feeding bin 6. Using its robotic arm, it grasps the hopper and moves it to the upper opening of the feeding bin 6, pouring the metal scraps into the feeding bin 6. Then, the second drive mechanism drives the flip-up cover 8 to close the opening of the feeding bin 6, and the first drive mechanism drives the flip-up baffle 7 to flip, opening the upper opening of the preheating zone 11, allowing the scraps in the feeding bin 6 to enter the preheating zone 11. The first drive mechanism then drives the flip-up baffle 7 to flip, closing the upper opening of the preheating zone 11.

[0036] During the melting stage, the first electric heating burner 21 is not working, while the second electric heating burner 13 is working. The operating temperature of the second electric heating burner 13 is controlled by a temperature control system to meet the metal melting requirements. Metal scraps in the preheating zone 11 enter the melting zone 12 through a conduit under gravity. Hot air is blown into the melting zone 12 through the air supply pipe 33 via the second electric heating burner 13. The second electric heating burner 13 heats the flowing air, melting the metal scraps. After melting, the metal scraps flow from the melting zone 12 into the heat preservation chamber 2 for heat preservation.

[0037] During the heat preservation stage, when the temperature detection mechanism inside the heat preservation chamber 2 detects a decrease in temperature, the electric heating rod 9 is activated to heat the molten metal. The solenoid valve at the connection between the air supply pipe 33 and the heat preservation chamber 2 opens, and the exhaust fan 34 is activated. The exhaust fan 34 draws hot air from the preheating zone 11, and the inert gas in the inert gas storage tank 4 enters the air supply pipe 33 through the pressure reducing valve 41. The exhaust fan 34 mixes and pressurizes the inert gas and hot air before sending it to the electric heating mechanism 31. The electric heating mechanism 31 heats the gas and then sends it from the air supply pipe 33 into the gas channels provided by the first electric heating burner 21 and the second electric heating burner 13. The gas enters the heat preservation chamber 2 from the first electric heating burner 21 and enters the melting zone 12 from the second electric heating burner 13. The exhaust fan 34 pressurizes the gas in the air supply pipe 33 and sends it into the insulation chamber 2 and the melting zone 12. Hot gas enters the preheating zone 11 from the melting zone 1 through the conduit, preheating the metal scraps in the preheating zone 11. Because the exhaust fan 34 pressurizes the gas sent into the melting zone 1, the gas passes quickly through the conduit connecting the preheating zone 11 and the melting zone 1, preventing the metal scraps from clogging the conduit. After the hot gas in the preheating zone 11 preheats the metal scraps, it cools down and is then drawn back into the electric heating mechanism 31 by the exhaust fan 34 for reheating, forming a cycle.

[0038] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the scope of protection of this utility model.

Claims

1. An electrically heated oxygen-free circulating melting and holding furnace, characterized in that: The furnace includes a melting chamber (1) and a heat preservation chamber (2). The heat preservation chamber (2) is located below the melting chamber (1) and the melting chamber (1) and the heat preservation chamber (2) are connected. A waste heat recovery heating system is connected between the melting chamber (1) and the heat preservation chamber (2). The waste heat recovery heating system extracts hot air from the melting chamber (1), heats the hot air, and then inputs it into the melting chamber (1) and the heat preservation chamber (2). The waste heat recovery heating system includes an electric heating mechanism (31). The electric heating mechanism (31) is connected to the melting chamber (1) through an exhaust pipe (32). The electric heating mechanism (31) is connected to the heat preservation chamber (2) through an air supply pipe (33). The exhaust pipe (32) is equipped with an exhaust fan (34). The exhaust fan (34) extracts hot air from the melting chamber (1) and sends it into the electric heating mechanism (31).

2. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 1, characterized in that: The electric heating mechanism (31) is equipped with an inert gas storage tank (4), which is connected to an exhaust pipe (32) via a pipeline. An electromagnetic valve is provided at the pipeline connecting the inert gas storage tank (4) and the exhaust pipe (32).

3. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 1, characterized in that: The heat preservation chamber (2) is provided with a first electric heating nozzle (21) on its side wall, and the melting chamber (1) is provided with a second electric heating nozzle (13) on its side wall. The air supply pipe (33) is connected to the first electric heating nozzle (21) and the second electric heating nozzle (13) respectively. The air supply pipe (33) blows hot air to the heat preservation chamber (2) and the melting chamber (1) respectively through the first electric heating nozzle (21) and the second electric heating nozzle (13).

4. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 3, characterized in that: The air supply pipe (33) is equipped with a blower (35), which sends the gas heated by the electric heating mechanism (31) from the first electric heating burner (21) into the heat preservation chamber (2).

5. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 3, characterized in that: The melting chamber (1) includes a preheating zone (11) and a melting zone (12). The preheating zone (11) is located on the upper side of the melting zone (12). The preheating zone (11) and the melting zone (12) are connected by a conduit. The second electric heating nozzle (13) is located on the side wall of the melting zone (12). The exhaust pipe (32) is connected to the preheating zone (11). The melting zone (12) is connected to the air supply pipe (33) through the second electric heating nozzle (13). The metal in the preheating zone (11) is preheated by the hot air in the melting zone (12). The metal enters the melting zone (12) under the action of gravity. The metal is heated and melted by the hot air blown out by the second electric heating nozzle (13).

6. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 5, characterized in that: The preheating zone (11) is provided with a feeding bin (6) at the top, and a flip-up baffle (7) is connected between the preheating zone (11) and the feeding bin (6); one side of the flip-up baffle (7) is hinged to the top opening of the preheating zone (11), and the flip-up baffle (7) is driven by a first driving mechanism, which drives the flip-up baffle (7) to flip; when the flip-up baffle (7) is in a horizontal position, the flip-up baffle (7) separates the preheating zone (11) and the feeding bin (6).

7. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 6, characterized in that: A hinged flip-top cover (8) is connected to the upper opening of the feeding bin (6). The flip-top cover (8) is driven by a second driving mechanism, which drives the flip-top cover (8) to rotate. When the flip-top cover (8) is in a horizontal position, the flip-top cover (8) closes the upper opening of the feeding bin (6).

8. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 1, characterized in that: An electric heating rod (9) is connected inside the heat preservation chamber (2), and the electric heating rod (9) assists in heating the molten material inside the heat preservation chamber (2).

9. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 2, characterized in that: A pressure reducing valve (41) is provided at the connection between the inert gas storage tank (4) and the exhaust pipe (32). The pressure reducing valve (41) reduces the gas pressure inside the inert gas storage tank (4) and keeps the output gas pressure stable.

10. The electrically heated oxygen-free circulating smelting and holding furnace according to claim 1, characterized in that: A feeding mechanism (5) is provided near the smelting and holding furnace, and the feeding mechanism (5) is a feeding robot.

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