Melting furnace and method for melting metal material

Abstract

The invention relates to a furnace (1) for melting a metallic material (2), comprising: a receiving region (3) for receiving the metallic material (2), which is in a solid aggregate state of the metallic material (2); a gas combustion device (13) arranged in the receiving region (3), by means of which the material (2) in the receiving region (3) can be heated by combustion gas and can be melted therefrom; the invention relates to a heat-insulating material (2), comprising a heat-insulating region (14) for accommodating a melt (15) formed from the material (2) resulting from the melting of the material (2), comprising an electrically operable heating device (16), by means of which the melt (15) in the heat-insulating region (14) can be insulated.

Description

Technical Field

[0001] The invention relates to a furnace for melting metallic material according to the preamble of claim 1. Furthermore, the invention relates to a method for melting metallic material according to the preamble of claim 7. Background Art

[0002] DE10325153A1 discloses a device for melting and keeping metal warm, which has a furnace for accommodating a molten pool. In addition, DE19613570A1 discloses a method for completely burning out furnace gases containing carbon monoxide in a vertical smelting furnace. In addition, DE1199794B discloses a method for direct reduction of iron ore. Summary of the invention

[0003] The object of the present invention is to provide a furnace for melting metallic material and a method for melting metallic material in which particularly low-emission operation is possible.

[0004] This object is achieved according to the invention by a furnace having the features of claim 1 and by a method having the features of claim 7. Advantageous embodiments of the invention are the subject of the dependent claims.

[0005] A first aspect of the invention relates to a furnace for melting metallic materials, i.e. metals. This can be understood to mean that the furnace is suitable for melting different metals. However, it is particularly preferred that the furnace is suitable for melting aluminum. Thus, a body consisting of a metallic material and initially solid (i.e. initially constructed as a solid) can be melted by means of the furnace. For example, a metal ingot consisting of a metallic material can be melted by means of the furnace. For this purpose, the furnace has a receiving area in which the metallic material can be at least temporarily received (in particular in a solid aggregate state of the metallic material and / or in a liquid aggregate state of the metallic material). This should be understood in particular to mean that, for example, a first portion of the material can be received in the receiving area in a solid aggregate state. Alternatively or additionally, for example, a second portion of the material can be received in the receiving area in a liquid aggregate state. The receiving area is also referred to as a charging area, because the metallic material can be introduced into the receiving area in a solid aggregate state of the metallic material and then at least temporarily received in the receiving area. The furnace also has a gas burner which is arranged at least partially in the receiving area, by means of which the material in the receiving area can be heated by combustion gas and can thereby be melted. In other words, the gas can be supplied to the gas burner, for example, as a gaseous fuel, wherein the gas can be burned by means of the burner (in particular in the burner), in particular with the formation of flames and / or burner exhaust gases. The flames and / or burner exhaust gases can, for example, flow out of the gas burner and in particular flow directly into the receiving area, whereby the material arranged in the receiving area can be heated in the receiving area and can subsequently be melted.

[0006] The furnace also has a heat preservation area, in which the material can be accommodated at least temporarily in a liquid state of the material, for example. It is also conceivable that another liquid material can be accommodated at least temporarily in the heat preservation area, which is filled or already filled into the heat preservation area, for example, especially via the accommodation area and / or bypassing the accommodation area. Therefore, the other material is also called filler material. In other words, the following liquid can be accommodated at least temporarily in the heat preservation area, which liquid, for example, has the material in the liquid state of the material and / or the other material in the liquid state of the other material. In particular, for example, a melt formed by the material and thus formed by the melted material produced by the melting of the material can be accommodated at least temporarily in the heat preservation area. Therefore, for example, the liquid has a melt. In other words, the material is liquefied by the described material melting occurring in the accommodation area (charging area), that is, it is converted into a melt, which can, for example, flow from the accommodation area to the heat preservation area via at least one or exactly one fluid connection between the accommodation area and the heat preservation area. The melt can be collected in the insulation region and at least temporarily accommodated in the insulation region while forming a pool (Bad) also referred to as a melt pool. For example, the fluid connection between the accommodation region and the insulation region is always, that is, permanently arranged, so that, for example, the insulation region and the accommodation region are permanently fluidly connected to each other. Therefore, for example, no separation device is provided, but the insulation region and the accommodation region are, for example, permanently and therefore always (that is, always) fluidly connected to each other, and the separation device can be switched between an open state and a closed state, the open state makes the insulation region and the accommodation region fluidly connected to each other and thus releases the fluid connection between the insulation region and the accommodation region, and in the closed state, the accommodation region and the insulation region are fluidly separated from each other, that is, the fluid connection between the accommodation region and the insulation region is interrupted. It is also conceivable to provide the separation device that can be switched between a closed state and an open state. In the closed state, the insulation region and the accommodation region are fluidly connected to each other by means of the separation device. In other words, the fluid connection between the insulation region and the accommodation region is interrupted in the closed state by means of the separation device. In the open state, a fluid connection is formed between the heat-retaining area and the receiving area, or in the open state, the separation device releases the fluid connection between the heat-retaining area and the receiving area, so that the heat-retaining area is fluidly connected to the receiving area in the open state. The heat-retaining area and the receiving area are also collectively referred to as areas of the furnace.

[0007] In order to enable a particularly low-emission operation of the furnace, especially with regard to the carbon dioxide emissions of the furnace, i.e. to be able to keep the carbon dioxide emissions of the furnace particularly low, it is provided according to the invention that the furnace has an electrically operable, i.e. operable, heating device, with the aid of which the melt in the holding zone can be held warm with the aid of electric energy (the heating device is operated with the electric energy or can be operated with the electric energy). In particular, it is provided that the holding zone can be heated and thus held warm with the aid of the heating device, and thus the melt in the holding zone can be heated and thus held warm. Usually, the melt in the holding zone is held warm with the aid of a burner, so that the burner, which can be a component of a gas combustion device, burns gas. Thus, the burner provides, for example, a burner flame and / or an exhaust gas, wherein the burner flame and / or the exhaust gas of the burner are especially introduced directly into the holding zone, so as to thereby hold the melt in the holding zone warm. The operation of such a burner with combustion gas can now be avoided by the present invention, because in the present invention or by the present invention, the melt can be kept warm by means of an electric heating device and thus by means of electrical energy. Keeping the melt warm should be understood in particular as preventing the liquid melt contained in the holding area from solidifying, i.e. preventing it from solidifying. Compared with conventional solutions, the present invention can avoid excessive carbon dioxide emissions in two aspects in particular. On the one hand, carbon dioxide is produced in a gas-operated burner, which burns gas during its operation, for example, to keep the melt in the holding area warm, and the carbon dioxide enters the holding area and / or is produced in the holding area. The carbon dioxide is usually sucked from the holding area and / or from the holding area, and is in particular the first part of the carbon dioxide emissions of a conventional melting furnace. The second part of the carbon dioxide emissions of a conventional melting furnace is produced in particular by operating a suction device, also called a ventilation device, in order to suck carbon dioxide from the holding area and / or from the holding area during the holding of the melt, by means of which carbon dioxide is actively sucked from the holding area and / or the holding area during the holding of the melt. For this purpose, the suction device is operated electrically, i.e. with the aid of electrical energy, wherein said operation of the suction device also generates carbon dioxide, which is the second part of the carbon dioxide emissions of conventional furnaces mentioned above. With the invention, it is now possible to avoid not only carbon dioxide emissions resulting from the operation of the gas burners for keeping the melt warm, but also carbon dioxide emissions resulting from the operation of the suction device for actively sucking gas from the holding area and / or from the receiving area during the holding of the melt. The invention thus enables a particularly low carbon dioxide emission operation of the furnace. The invention is particularly advantageous in that the furnace is operated in a holding operation during which, although the liquid melt contained in the holding area is kept warm by means of the heating device, the material in the receiving area is not melted by means of the gas burner, and therefore no gas is burned by the gas burner.In the holding operation, for example, the carbon dioxide emissions of the furnace can be kept particularly low, especially compared to conventional technical solutions. In this regard, the present invention is based in particular on the recognition that, on the one hand, electric heating devices are not suitable for melting metal materials. For this purpose, compared to melting metal materials by means of gas burners and therefore using gas, very high electrical power is required, which will produce higher carbon dioxide emissions than melting metal materials by means of gas, i.e. by means of gas burners. On the other hand, electric heating devices are particularly suitable for keeping the liquid melt in the holding area warm, more precisely, preferably not by gas burners, i.e. not by burning gas, to keep the melt in the receiving area warm. Therefore, the present invention combines the advantages of gas burners with the advantages of heating devices. With the help of gas burners, metal materials, such as aluminum ingots, can be melted in an energy-advantageous, i.e. particularly efficient, manner in the melting operation. With the help of electric heating devices, a melt, such as a molten aluminum or formed as molten aluminum, can be kept warm in an energy-efficient manner in the holding area, so that a particularly low-emission operation of the furnace can be achieved overall. The above-mentioned holding operation is carried out, for example, during downtime of the foundry installation including the furnace, for example during weekends and / or during maintenance work. During these time periods, no melt and therefore no melting of the metal material is required. By combining an electric heating device, also referred to as an electric heater, with a gas combustion device, a very energy-saving operation of the furnace can be achieved, in particular in the holding operation, also referred to as holding mode.

[0008] In order to be able to keep the liquid melt in the holding region particularly energy-efficiently by means of the heating device, and thus to ensure particularly low-emission operation of the furnace, it is provided in one embodiment of the invention that the holding region, in particular with regard to the position of use of the furnace, is at least partially overlapped in the vertical direction upwards and / or downwards by the electric heating device. The position of use of the furnace is the position of the furnace provided for the intended use of the furnace, i.e. for the intended application of the furnace, in which the furnace is used to melt metallic material and to keep the melt in the holding region warm.

[0009] Another embodiment is characterized in that the heating device is arranged on or in the bottom of the furnace, which bottom (especially with respect to the position of use of the furnace) delimits the holding area in the vertical direction downwards. This ensures particularly energy-efficient operation of the furnace, especially in holding operation.

[0010] It is conceivable that the melt in the insulation zone is insulated by means of a heating device in the insulation operation. It is also conceivable that the melt in the insulation zone is not insulated by an electric heating device in the melting operation, or the melt in the insulation zone is insulated by means of a heating device in the melting operation.

[0011] In another particularly advantageous embodiment of the invention, it is provided that the heating device is arranged on or in a roof of the furnace, which roof (in particular with regard to the position of use of the furnace) delimits the holding region in a vertical direction upwards. It has been found that the arrangement of the heating device in or on the roof is particularly advantageous in order to achieve a particularly energy-efficient operation of the heating device, i.e. the melt in the holding region can be held in a particularly energy-efficient manner.

[0012] For example, the electric heating device comprises at least one heating element, in particular as a first heating element, wherein the heating element is arranged, for example, on or in the bottom or on or in the top.

[0013] In order to enable particularly low-emission operation of the furnace and to keep the costs of the furnace within a particularly low range, a further embodiment of the invention provides that the furnace has no gas burners for direct heating of the holding zone. Such gas burners for direct heating of the holding zone are to be understood in particular as burners which burn gas, i.e. gaseous fuel, during their operation and thereby provide flames and / or exhaust gases which are introduced directly into the holding zone.

[0014] Another embodiment is characterized in that the heating device has at least one resistance heating element for heating the insulation region. In particular, the resistance heating element can be a heating element mentioned above. As a result, the insulation region can be insulated in a particularly energy-efficient and thus low-CO2-emission manner.

[0015] Finally, it has proven to be particularly advantageous if the receiving area and the holding area are designed as a unit that cannot be separated without loss. This means, for example, that the receiving area and the holding area are formed by housing parts that are, for example, designed to be independent of one another and are fixedly connected to one another, i.e. cannot be disassembled without loss, and thus form a unit, or that the housing parts are designed to be integral with one another, i.e. are formed from a single piece. Therefore, emptying of the melt or the holding area, i.e. the discharge of the melt from the holding area, can only be achieved as a whole by tilting the entire furnace (i.e. by jointly tilting the receiving area and the holding area) or by pumping out, in particular pumping out of the holding area.

[0016] A second aspect of the present invention relates to a method for melting a metal material by means of a furnace, in particular a furnace according to the first aspect of the present invention. In the method, the furnace has a holding area, which is also referred to as a charging area. The metal material is at least temporarily held in the holding area in a solid state of the metal material. The furnace has a gas burner arranged in the holding area, by means of which the material in the holding area is heated by combustion gas and thereby melted. This should be understood in particular that the gas is burned as a gaseous fuel by means of the gas burner (in particular in the gas burner and completely in the chamber of the gas burner), whereby, for example, the gas burner provides exhaust gas and / or flame. The exhaust gas provided by the gas burner and / or the flame provided by the gas burner (in particular directly) are introduced into the holding area so as to heat the material in the holding area and subsequently melt it. In the method, the furnace has a heat preservation area, and the melt formed by the material and produced by the melting of the material is held in the heat preservation area.

[0017] The melting furnace may be designed, for example, as a vertical melting furnace, or as an inclined furnace, or as another furnace, ie, as another device for melting metal materials.

[0018] In order to now enable a particularly low-emission operation of the furnace, especially with regard to the carbon dioxide emissions of the furnace, it is provided in a second aspect of the invention that the furnace has an electrically operable heating device, by means of which the melt in the holding area is held warm using electrical energy, the heating device being supplied with the electrical energy, whereby the heating device is electrically operated. The advantages and advantageous configurations of the first aspect of the invention can be regarded as advantages and advantageous configurations of the second aspect of the invention, and vice versa.

[0019] In order to be able to achieve a particularly low-emission operation of the furnace, in an embodiment of the second aspect of the invention it is provided that the furnace is operated in a certain holding operation or in the manner of the holding operation mentioned above. In the holding operation, the melt is kept warm by means of an electric heating device which is electrically operated in the holding operation, while the combustion operation of the gas burner is stopped, in which the gas burner burns gas and thus heats the material in the receiving area. It is therefore preferably provided that in the holding operation, the gas burner does not burn gas and thus does not heat the material in the receiving area. Excessive carbon dioxide emissions from the furnace can thereby be avoided, in particular during shutdowns.

[0020] In order to enable particularly low-emission operation of the furnace, a further embodiment of the invention provides that during the holding operation, active extraction of gas from the holding area or from the receiving area is stopped. The background of this embodiment is that, since the combustion device does not burn gas during the holding operation, no carbon dioxide or gas containing carbon dioxide is generated, which has to be extracted from the receiving area or the holding area. Therefore, during the holding operation, active extraction of carbon dioxide from the holding area or from the receiving area can be stopped, thereby enabling particularly energy-efficient operation of the furnace.

[0021] Finally, it has proven to be particularly advantageous to operate the furnace in a melting operation or in the above-mentioned melting operation, in which the gas burner is operated in the combustion operation. In the combustion operation, the gas burner burns gas, whereby the gas burner heats and melts the material in the receiving area. During this time, an extraction device (especially electric) is operated, whereby gas and thus carbon dioxide are actively extracted from the receiving area and / or from the holding area by means of the extraction device of the furnace. This makes it possible to achieve safe operation and, as described above, to melt the metal material particularly energy-efficiently by means of the gas burner. This makes it possible to ensure an operation of the furnace with particularly low carbon dioxide emissions, especially in the case of a melting operation and a holding operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Further details of the invention are obtained from the following description of preferred embodiments with the aid of the associated drawings. Figure 1 A schematic and cut-away side view of a furnace for melting metallic material is shown. DETAILED DESCRIPTION

[0023] The only Figure 1 A schematic and cut-away side view of a furnace 1 for melting a metallic material 2 is shown. Figure 1 In the embodiment shown in , the melting furnace 1 is designed as a vertical melting furnace. However, the above and the following embodiments can of course and without a doubt also be transferred to other devices for melting metal materials, such as the metal material 2.

[0024] The furnace 1 has a receiving area 3, also referred to as a charging area, in which the metal material 2 is received or can be received in a solid aggregate state of the metal material 2. Figure 1 4 shows a detection device 4 in a particularly schematic manner, by means of which the fill level of the metallic material 2 in the receiving area 3 can be detected, ie a measurement parameter which characterizes the amount of the material 2 arranged in the receiving area 3. Figure 1In the embodiment shown in , the detection device 4 is designed as a laser detection device, by means of which a laser beam 5 is provided or provided or can be provided. The measurement parameter is detected by means of the laser beam 5. In particular, the measurement parameter is the height (also called fill level height) of the material 2 in the receiving area 3, in particular in relation to a predeterminable or predefined initial height or in relation to a predeterminable or predefined initial level. Figure 1 In the embodiment shown in , the receiving area 3 is a shaft. The receiving area 3 itself has an opening 6, wherein the receiving area 3 itself is open in the vertical direction upwards, in particular through the opening 6. The vertical direction is indicated by a double arrow 7. For example, the furnace 1 is operated, in particular in the melting operation and / or the holding operation of the furnace 1, according to the measured parameters detected by means of the detection device 4.

[0025] The furnace 1 also has a charging device 8, by means of which the material 2 can be charged from outside the receiving area 3 (in particular automatically) into the receiving area 3. For this purpose, for example, a portion of the material 2, which is indicated by T, can be arranged in a moving element 9, which is designed as an elevator, for example, and can be introduced from outside the receiving area 3, in particular charged into the receiving area 3, by means of the moving element 9.

[0026] The opening 6, which is designed as a through opening, is arranged on the side of the receiving area 3 pointing upward in the vertical direction (double arrow 7), whereby the receiving area 3 itself is open upward in the vertical direction. The opening 6 is provided with a cover 10. The receiving area 3 and the opening 6 are delimited (in particular directly) by the housing 11 of the melting furnace 1. The cover 10 is held on the housing 11 so that it can be moved relative to the housing 11, in particular so that it can be pivoted, in particular so that the cover 10 can be moved. Figure 1 1 and a closed position relative to the housing 11. In the open position, the lid 10 releases the opening 6, so that in the open position the material 2 can be introduced, in particular filled, into the receiving area 3 via the opening 6. In the closed position, the opening 6 and thus the receiving area 3 are closed in the vertical direction upwards by means of the lid 10.

[0027] The furnace 1 also has an extraction device 12, also referred to as a ventilation device, which will be described in more detail below. The furnace 1 also has a gas burner 13 arranged in the receiving area 3, by means of which the material 2 in the receiving area 3 can be heated by combustion gas and can be melted thereby. The feature "the material 2 in the receiving area 3 can be heated by combustion gas by means of the gas burner and can be melted thereby" is to be understood as meaning that the gas is burned as a gaseous fuel by means of the gas burner 13, in particular in at least one combustion chamber of the gas burner 13. Heat is thereby generated, which is provided, for example, by the gas burner 13. The material 2 is heated by means of the heat and is melted thereby. For example, exhaust gas and / or flame are generated by the combustion of the gas, which exhaust gas or flame is discharged, for example, from the gas burner 13 and (in particular directly) introduced into the receiving area 3. As a result, the material 2 in the receiving area 3 is heated and subsequently melted.

[0028] The gas burner 13 is arranged at least partially in the receiving region 3. The melting furnace 1 also has a holding region 14 in which a melt 15 produced by the melting of the material 2 and formed from the material 2 is or can be received at least temporarily.

[0029] In order to now enable a particularly low-CO2 operation of the furnace 1, the furnace 1 has an electrically operable heating device 16, by means of which the melt 15 in the holding region 14 can be held warm using electrical energy. This means that the heating device 16 is supplied with electrical energy, by means of which the heating device 16 is electrically operated. The heating device 16 thus provides heat, by means of which the melt 15 in the holding region 14 is held warm and thereby in particular is kept in a liquid aggregate state of the melt 15.

[0030] It can be seen that the holding region 14 is delimited vertically upwards (in particular directly) by a roof 17 of the furnace 1, in particular the housing 11. The holding region 14 is delimited vertically downwards (in particular directly) by a bottom 18 of the furnace 1, in particular the housing 11. The heating device 16 has, for example, a heating element 19 arranged in the bottom 18, in particular in the form of a heating rod. Alternatively or additionally, the heating device 16 has, for example, a heating element 20 arranged in the roof 17, in particular in the form of a heating rod. The heating elements 19, 20 are, for example, electrical resistance heating elements, by means of which the holding region 14 and therefore the melt 15 arranged in the holding region 14 can be kept warm particularly advantageously, in particular particularly energy-efficiently.

[0031] The metallic material 2 is, for example, aluminum which is present in its solid aggregate state in the form of aluminum ingots in the receiving area 3 .

[0032] The furnace 1 has no gas burners for directly heating the holding zone 14 , so that a particularly cost-effective design of the furnace 1 and a particularly low-emission operation are possible.

[0033] In the method for operating the melting furnace 1, the melting furnace 1 is operated in the above-mentioned holding operation. In the holding operation, the melt 15 in the holding area 14 is held warm by means of the electric heating device 16, while the combustion operation of the gas burner 13 is stopped. In the combustion operation of the gas burner 13, the gas is burned in the gas burner 13, and the material 2 in the receiving area 3 is heated thereby. It is further preferably provided that in the holding operation, active gas extraction from the holding area 14 or from the receiving area 3 is stopped.

[0034] For example, the furnace 1 is operated in the above-mentioned melting operation before and / or after the holding operation. In the melting operation, the gas burner 13 is operated in the combustion operation, in which the gas burner burns gas in itself and heats and melts the material 2 in the receiving area 3, while actively sucking gas from the receiving area 3 and, for example, from the holding area 14 via the receiving area 3 by means of the suction device 12, and thus actively sucking carbon dioxide, for example, generated by the combustion operation. For this purpose, the suction device 12 is operated by means of electrical energy, in that the suction device 12 is supplied with electrical energy. For example, in the melting operation, the lid 10 is open, i.e., the lid 10 is in its open position in the melting operation. In the holding operation, the lid 10 is, for example, closed, i.e., the lid 10 is then in the closed position. In particular, the melting furnace 1, which is also referred to as a furnace for short, can be operated autonomously, in particular controlled or regulated autonomously. For example, when the lid 10 is open, the melting furnace 1 is operated in the melting operation. If the lid 10 is closed, for example because no material is to be melted in the receiving area 3, a switch is made from the melting operation to the holding operation. As a result, the carbon dioxide emissions of the melting furnace 1 can be kept particularly low. In particular, it is provided that the material in the receiving area 3 is not melted by means of the electric heating device 16. This ensures a particularly energy-efficient operation.

[0035] The furnace 1 is, for example, a component of a smelter, in particular of an aluminum smelter. In particular, the furnace 1 can be a component of a foundry in which components are produced by casting from a melt 15. This allows a particularly low-emission operation of the smelter or foundry as a whole. Reference numerals list

[0036] 1 Furnace

[0037] 2Metal Materials

[0038] 3Accommodation area

[0039] 4. Detection device

[0040] 5 Laser beam

[0041] 6 Opening

[0042] 7 Double Arrows

[0043] 8. Loading device

[0044] 9 Motion Components

[0045] 10. Lid

[0046] 11 Shell

[0047] 12 Suction device

[0048] 13 Gas combustion device

[0049] 14 Insulation Area

[0050] 15 Melt

[0051] 16 Electric heating device

[0052] 17 Top

[0053] 18 Bottom

[0054] 19 Heating elements

[0055] 20 Heating Elements

[0056] T Section

Claims

1. A furnace (1) for melting a metal material (2), the furnace comprising: a receiving area (3) for receiving the metal material (2); a gas combustion device (13) arranged in the receiving area (3), the material (2) in the receiving area (3) being heatable by combustion gas by means of the gas combustion device and being meltable thereby; and a heat-insulating area (14), It is characterized in that An electrically operable heating device (16) is provided, by means of which the melt (15) in the holding region (14) can be held at a temperature.

2. The furnace (1) according to claim 1, characterized in that The heat-retaining area (14) is at least partially overlapped by the heating device (16) upwards and / or downwards in the vertical direction (7).

3. The furnace (1) according to claim 1 or 2, characterized in that The heating device (16) is arranged at or in a bottom (18) of the furnace (1), and the bottom delimits the heat-retaining area (14) downward in a vertical direction.

4. A furnace (1) according to any one of the preceding claims, characterised in that The heating device (16) is arranged at or in a top (17) of the furnace (1), and the top delimits the heat-insulating area (14) upwardly in a vertical direction (14).

5. A furnace (1) according to any one of the preceding claims, characterised in that The furnace (1) has no gas burners for directly heating the holding zone (14).

6. A furnace (1) according to any one of the preceding claims, characterised in that The heating device (16) has at least one resistance heating element (19, 20) for heating the insulation region (14).

7. A method for melting a metal material (2) by means of a melting furnace (1), wherein the melting furnace (1) comprises: - a receiving area (3), in which the metal material (2) is received in a solid aggregate state of the metal material (2); - a gas burning device (13) arranged in the receiving area (3), by means of which the material (2) in the receiving area (3) is heated by combustion gas and thereby melted; and - a holding region (14) in which a melt (15) formed from the material (2) and resulting from the melting of the material (2) is accommodated; It is characterized in that an electrically operable heating device (16) is provided, by means of which the melt (15) in the holding region (14) is held warm during use.

8. The method according to claim 7, characterized in that The melting furnace (1) is operated in a heat-keeping mode, in which the melt (15) is kept warm by means of an electric heating device (16), while the combustion mode of the gas burner (13) is stopped, in which the gas burner (13) burns gas and thereby heats the material (2) in the receiving area (14).

9. The method according to claim 8, characterized in that During the heat-keeping operation, active extraction of gas from the heat-keeping area (14) or from the containing area (3) is stopped.

10. The method according to claim 7 or 8, characterized in that: The furnace (1) is operated in a melting operation mode, and in the melting operation the gas burner (13) is operated in a combustion operation mode, in which the gas burner (13) burns gas and thereby heats and melts the material (2) in the receiving area (3), while the gas is actively sucked out of the receiving area (3) and / or from the holding area (14) by means of a suction device (12) of the furnace (1).

11. A furnace (1) according to any one of the preceding claims, characterised in that The receiving area (3) and the heat-insulating area (14) are implemented as units that cannot be separated without loss.

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