Three-chamber smelting furnace for aluminum scrap and method of operation

Abstract

A smelting furnace (200) for smelting aluminum scrap (S) contaminated with volatile organic compounds (VOCs), the smelting furnace comprising a cold chamber (222), at least a first hot chamber (224a) and a second hot chamber (224b), at least one regenerative burner assembly (228) and at least one regenerator assembly (230), the regenerative burner assembly being configured to perform combustion in the first hot chamber (224a) and the second hot chamber (224b), the regenerator assembly being configured to draw flue gas from the first hot chamber (224a) and the second hot chamber (224b), heat a storage structure through the flue gas, and introduce heated air from the storage structure into the cold chamber (222).

Description

Technical Field

[0001] The present invention belongs to the technical field of systems for manufacturing aluminum; in particular, the present invention relates to a three-chamber melting furnace for aluminum scrap. Background Art

[0002] With the advancement of modern environmental protection and sustainable development policies, the recycling and conversion process for aluminum scrap has been widely applied. Recycling aluminum scrap during the melting process can indeed significantly reduce the consumption of aluminum ore and emissions associated with the conversion process.

[0003] However, melting aluminum scrap has certain drawbacks. In fact, this is mainly because a single scrap piece does not only contain aluminum parts. In fact, in a single piece, besides aluminum parts, there may also be parts made of organic materials, generally referred to as VOCs (volatile organic compounds), such as coatings, polymer materials, glues, adhesives, and other compounds derived from hydrocarbons. These compounds are bonded to the metal parts and are difficult to separate. For example, in scrap sourced from recycled hardware accessories, aluminum parts such as window frames are sprayed and equipped with adhesive gaskets.

[0004] During the scrap melting process, volatile organic compounds will generate harmful fumes. Therefore, it is necessary to fully combust these fumes, which both neutralizes the fumes and prevents harmful substances from diffusing into the environment, and also utilizes the calorific value of these compounds to facilitate the melting of scrap.

[0005] There are some combustion processes that attempt to meet such requirements.

[0006] For example, known melting furnaces from Hertwich Engineering Gmbh include SCMF (marked as particularly suitable for scrap with VOC<1%), ECOMELT PR (marked as suitable for scrap with 1%<VOC<5%), and ECOMELT PS (marked as particularly suitable for scrap with VOC>5%). The WASTOX® combustion process and AIROX® combustion technology from LINDE AG are also well known.

[0007] Examples of melting furnaces are shown in US 2001 / 028136 A1 and CN 206 583 290 U.

[0008] Figure 1A conventional smelting furnace (standard dual-chamber furnace) is schematically shown, suitable for processing aluminum scrap with low volatile organic compound (VOC) content (VOC < 1%). Access to the furnace 1 is via a door 2, behind which is a drying base plate 3 on which the scrap 4 to be smelted is arranged. In front of the drying base plate 3 is a storage tank 5 containing a molten pool 6. A vertically extending wall 7 above the free surface of the molten pool 6 divides the interior of the furnace 1 into a cold chamber 8 and a hot chamber 9. The cold chamber contains a portion 6a of the molten pool and is equipped with the door 2 and the drying base plate 3. The hot chamber contains another portion 6b of the molten pool and is equipped with a burner assembly 10. The wall 7 also has an opening 15 that connects the hot chamber 9 and the cold chamber 8. The burner assembly 10 includes burners 11 and 12 operating in the hot chamber 9. The hot chamber 9 has a flue gas outlet 13; sometimes the cold chamber 8 also has a flue gas outlet 14.

[0009] Waste 4 is preheated in cold chamber 8 due to heat from burners 11 and 12 operating in hot chamber 9; in other words, the heat generated by burners 11 and 12 in hot chamber 9 is directly used to preheat waste 4 in cold chamber 8. The preheated waste 4 is then immersed in molten pool 6a, where smelting is completed. Flue gas formed from volatile organic compounds generated in cold chamber 8 enters hot chamber 9, where it can be burned by excess air from burners 11 and 12 and extracted by flue gas outlet 13.

[0010] However, the combustion of flue gas from volatile organic compounds (VOCs) is not always optimal. Increased VOC release from highly polluting wastes often concentrates emissions in a single step of the preheating process for dried waste (waste temperatures between 250°C and 450°C). In standard dual-chamber furnaces with increased VOC content, complete combustion of unburned materials is impossible because an increased air volume is required, which cannot be introduced into the burner as excess air (burners cannot operate with an air / gas ratio exceeding design limits, typically equal to air / gas = 15). Strong turbulent mixing is also required to burn off unburned VOCs, and the regenerative burner design of standard dual-chamber furnaces fails to effectively introduce excess air. Furthermore, the flue gas produced by this combustion contains toxic substances. Summary of the Invention

[0011] The object of this invention is to provide a three-chamber smelting furnace for aluminum scrap, which exhibits significant effectiveness and efficiency in treating aluminum scrap contaminated with volatile organic compounds (VOCs), thereby improving currently available processes and systems. In particular, the object of this invention is to provide a three-chamber furnace that allows for the feeding of highly contaminated scrap, extracts all volatile components from the scrap, and utilizes all or almost all of the calorific value of the VOCs in the furnace, thereby significantly reducing natural gas consumption.

[0012] Such an objective is achieved by the smelting furnace according to claim 1 and the operating method according to claims 16 and 17. The dependent claims describe other advantageous embodiments of the invention. Attached Figure Description

[0013] Figure 1 A standard dual-chamber melting furnace according to existing technology is shown.

[0014] The features and advantages of the three-chamber melting furnace and its operating method according to the invention will become clear from the following description, given by way of non-limiting example, based on further illustrations in the accompanying drawings, wherein:

[0015] - Figure 3 The three-chamber and double regenerative melting furnace according to the present invention is schematically shown;

[0016] - Figure 3 This is a comparison table between the unit consumption of furnaces according to the prior art and furnaces according to the present invention. Detailed Implementation

[0017] Three-chamber and double regenerable melting furnaces

[0018] refer to Figure 2 A three-chamber smelting furnace (a smelting furnace with three chambers) for aluminum scrap is generally indicated by reference number 200; this scrap may also contain a certain proportion of volatile organic compounds (VOCs). This furnace is particularly suitable for processing aluminum scrap with a VOC content of 2 to 5% by weight (2 ≤ VOC ≤ 5%).

[0019] The smelting furnace 200 includes an internal compartment preferably having a rectangular planar shape, characterized by a length L and a width W, wherein the length L is greater than the width W. For example, according to one embodiment, the length L is 15 meters and the width W is 9 meters.

[0020] The internal compartment can be accessed by opening the door 204 from the main entrance 202, which is preferably located in the direction of the width W of the internal compartment. On the side opposite to the main entrance 202, the compartment is defined by the bottom wall 206; finally, the internal compartment is defined laterally by the side walls 208, 210.

[0021] The furnace 200 also includes a drying base plate 212 located in an internal compartment behind the main inlet 202. The drying base plate 212 is adapted to support aluminum scrap S, which is preferably divided into scrap portions Psi, where i=1……n, where Ps1 is the first scrap portion to enter and Psn is the last scrap portion to enter.

[0022] The furnace 200 also includes a storage tank 214 for containing a pool of molten metal B, which is located between the drying bottom plate 212 and the bottom wall 206 of the furnace 200.

[0023] The furnace 200 also includes a main partition wall 220 arranged in an internal compartment between the drying bottom plate 212 and the bottom wall 206, extending above the free surface of the molten pool B, defining a cold chamber 222 on one side of the main inlet 202 in the internal compartment, and a hot zone 223 on one side of the bottom wall 206.

[0024] The furnace 200 also includes a secondary partition wall 225 arranged in the hot zone 223, which is located between the bottom wall 206 and the main partition wall 220 and extends above the free surface of the molten pool B, thereby dividing the first hot chamber 224a and the second hot chamber 224b.

[0025] Specifically, the cold chamber 222 includes a portion of the storage tank 214, namely the portion extending from the drying bottom plate 212 to the main partition wall 220, such that a portion Bc of the molten metal pool B is located in the cold chamber 222, and the drying bottom plate 212 is also located in the cold chamber. The hot zone 223, conversely, includes another portion of the storage tank 214, namely the portion extending from the main partition wall 220 to the bottom wall 206; this other portion of the storage tank 214 is partially located in the first hot chamber 224a and partially located in the second hot chamber 224b, such that another portion Bha of the molten metal pool B is located in the first hot chamber 224a, and the last portion Bhb of the molten metal pool B is located in the second hot chamber 224b.

[0026] In other words, the three portions of the molten pools Bc, Bha, and Bhb in the three chambers 214, 224a, and 224b are connected by an opening in the partition wall located below the free surface.

[0027] The main partition wall 220 also has at least one first opening 226a, preferably multiple first openings, such as multiple calibration holes distributed on the main partition wall 220, which communicate the cold chamber 222 with the first hot chamber 224a.

[0028] The main partition wall 220 also has at least one second opening 226b, preferably multiple second openings, such as multiple calibration holes distributed on the main partition wall 220, which communicate the cold chamber 222 with the second hot chamber 224b.

[0029] The smelting furnace 100 includes a heat storage system, which includes a heat storage burner assembly 228 and a heat storage body assembly 230.

[0030] As expected, the furnace 200 also includes a regenerative burner assembly 228, which operates between and is configured to perform combustion in the hot chambers 224a and 224b. The burner assembly 228 includes a first regenerative burner 228a operating in the first hot chamber 224a and a second regenerative burner 228b operating in the second hot chamber 224b, which cooperate with each other. Each regenerative burner 228a and 228b includes a burner body and a regenerative body, respectively. Furthermore, each regenerative burner 228a and 228b includes accumulation structures 228a' and 228b', respectively, adapted to accumulate and heat the air to be heated, and to deliver the thereby heated air and combustible gas to the corresponding burner 228a and 228b for combustion in the hot chambers 224a and 224b.

[0031] For example, the first burner 228a is arranged on the bottom wall 206 of the first hot chamber 224a, in front of the main partition wall 220, while the second burner 228b is arranged on the bottom wall 206 of the second hot chamber 224b, in front of the main partition wall 220.

[0032] As expected, the furnace 200 also includes a heat storage assembly 230 operating between hot chambers 224a, 224b and cold chamber 222. The heat storage assembly 230 includes a first heat storage body 230a operating between the first hot chamber 224a and cold chamber 222, and a second heat storage body 230b operating between the second hot chamber 224b and cold chamber 222. Each heat storage body 230a, 230 is provided with storage structures 230a', 230b', for example made of ceramic, adapted to extract heat from the hot flue gas in the hot chambers 224a, 224b, store heat, accumulate heat from the hot flue gas, and release the accumulated heat to the air to be heated in the cold chamber 222. Importantly, it should be noted that the heat storage bodies 230a, 230b of the heat storage system are not directly connected to the burners 228a, 228b.

[0033] The first heat storage body 230a is connected to the air inlet pipe 232, the first air outlet pipe 234a, the first flue gas inlet pipe 236a, and the flue gas outlet pipe 238. The first air outlet pipe leads to the cold chamber 222, preferably at the drying base plate 212. The first flue gas inlet pipe draws flue gas from the first hot chamber 224a.

[0034] The second heat storage body 230b is alternatively connected to the air inlet pipe 232, the second air outlet pipe 234b, the second flue gas inlet pipe 236b, and the flue gas outlet pipe 238, which leads to the cold chamber 222, preferably at the drying base plate 212, and the second flue gas inlet pipe draws flue gas from the second hot chamber 224b.

[0035] During the first operating step, flue gas drawn from the first hot chamber 224a heats the storage structure 230a' of the first regenerator 230a, thereby allowing the storage of thermal energy; air to be heated is supplied to the storage structure 230a', and once heated, it is supplied to the cold chamber 222 via the first air outlet pipe 234a. Advantageously, the use of the regenerator and its storage structure allows for the storage and accumulation of thermal energy to heat the air to be supplied to the cold chamber, and reduces emissions of toxic substances produced by conventional regenerator burners.

[0036] Simultaneously, the air to be heated is delivered to the accumulation structure 228a' of the first burner 228a, which has been preheated in the previous operating steps. Once heated, the air is mixed with combustible gas and supplied for combustion in the first hot chamber 224a.

[0037] Meanwhile, the flue gas extracted from the second hot chamber 224b is transported to the storage structure 230b' of the second heat storage body 230b to heat the storage structure 230b'.

[0038] In addition, the flue gas drawn from the second hot chamber 224b is simultaneously transported to the accumulation structure 228b' of the second burner 228b to heat the storage structure.

[0039] During the first operating step, the flue gas from the first hot chamber 224a is transferred in the cold chamber 222 to aid in the heating of the waste, and the flue gas from the cold chamber 222 is transferred in the second hot chamber 224b to aid in combustion and thus in the smelting of the metal.

[0040] During the second operating step, the air to be heated is delivered to the storage structure, to the storage structure 230b' of the second heat storage body 230b that was heated in the previous operating step, and once heated, the air is delivered to the cold chamber 222 by means of the second air outlet pipe 234b.

[0041] Meanwhile, the air to be heated is conveyed to the storage structure and then to the accumulation structure 228b' of the second burner 228b that has been heated in the previous operating steps. Once heated, the air is mixed with the combustible gas and supplied to the combustion chamber 224b.

[0042] Meanwhile, the flue gas extracted from the first hot chamber 224a is transported to the storage structure 230a' of the first heat storage body 230a to heat the accumulation structure 228a'.

[0043] In addition, the flue gas drawn from the first hot chamber 224a is simultaneously transported to the accumulation structure 228a' of the first burner 228a to heat the accumulation structure 228a'.

[0044] During the first operating step, the flue gas from the first hot chamber 224a is transferred in the cold chamber 222 to aid in the heating of the waste, and the flue gas from the cold chamber 222 is transferred in the second hot chamber 224b to aid in combustion and thus in the smelting of the metal.

[0045] Furnace 200 also includes electronic management devices, such as electronic boards or microchips, which are operatively connected to furnace components to manage operating procedures.

[0046] According to the structural variant, furnace 200 includes at least one other burner 240 operating in cold chamber 214, or at least one other burner 241a operating in first hot chamber 224a, or at least one other burner 241b operating in second hot chamber 224b, with the primary purpose of increasing the temperature of one of the cold chamber 222 or hot chambers 224a, 224b when necessary.

[0047] The waste S, located on the drying base plate 212 of the cold chamber 222, is initially heated by the thermal environment (radiation at a temperature of 750°C) and the at least one other burner 240. When the waste S reaches a temperature of approximately 200°C, it will begin to release volatile organic compounds, which will be at least partially burned by the air introduced by the heat storage assembly 230, thereby generating heat to partially sustain the heating process of the waste itself.

[0048] Furthermore, portions of Psi from waste S are sequentially immersed into portions Bc of the cold chamber 222 of the molten pool B. In other words, portion Ps1 is immersed first, entering and approaching the storage tank 214 first; once portion Ps1 is immersed, other portions Ps2...Psn are advanced from the main inlet 202 toward the storage tank 214, while another portion Psn+1 is introduced into the furnace. Through batch feeding, the release of volatile organic compounds (VOCs) from the waste fed into the cold chamber 222 is thus dispersed. Each batch of portion Psi releases VOCs according to a curve including an ascending ramp, a peak phase, and a descending phase. Because there are several batches of feed on the drying plate, with waste at different release stages, a more uniform overall distribution of VOC release can be ensured.

[0049] Therefore, the fully heated waste portion (indicating approximately 550°C) is immersed in the molten pool to ensure that the volatile organic compounds are almost completely volatilized.

[0050] In the cold chamber 222, the air discharged from each heat storage body 230a, 230b reacts with the flue gas produced by the combustion of volatile organic compounds, forming a type of "distributed burner" in the cold chamber 222. That is, the flue gas obtained from the hot chambers 224a, 224b preheats the air in the cold chamber 222. In other words, thermal energy can be extracted from the flue gas discharged from the hot chambers 224a, 224b, stored in the storage structures 230a', 230b' of each heat storage body 230a, 230b, and transferred to the air entering the cold chamber 222.

[0051] Furthermore, according to a structural variation, the furnace 200 includes a first lance group 250a and a second lance group 250b. The first lance group includes at least one oxygen lance configured to introduce oxygen into a first hot chamber 224a, for example, through the opening 226a of the main partition wall 220. The second lance group includes at least one oxygen lance configured to introduce oxygen into a second hot chamber 224b, for example, through the opening 226b of the main partition wall 220.

[0052] Specifically, in the first operating step, the flue gas in the cold chamber 222 flows into the second hot chamber 224b, and oxygen is preferably introduced into the second hot chamber 224b by operating the second spray gun assembly 250b, so as to burn the flue gas originating from the cold chamber 222 in the second hot chamber 224b, which contains unburned volatile organic compounds.

[0053] In the second operating step, the flue gas in the cold chamber 222 flows into the first hot chamber 224a, and oxygen is preferably introduced into the first hot chamber 224a by operating the first spray gun assembly 250a so as to burn the flue gas originating from the cold chamber 222 in the first hot chamber 224a.

[0054] In addition, in one structural variant, the furnace 200 includes another flue gas outlet pipe operating in the first and second hot chambers for discharging a portion of the flue gas from the first and second hot chambers toward the processing system.

[0055] Therefore, according to the invention, a portion of the flue gas from the hot chamber is used to preheat the air to be introduced into the cold chamber by means of a regenerator assembly. This air is designed to completely or partially burn the volatile organic compounds (VOCs) released from the waste by directly recovering the heat released from the waste in the cold chamber and partially sustaining the heating of the waste itself. The flue gas from the cold chamber (containing some unburned VOCs) then flows into the hot chamber, where the combustion of the VOCs is accomplished by an oxygen lance (a three-chamber double regenerator). Thus, unburned emissions are reduced, and all the heat from the VOCs can be recovered and reused in the furnace.

[0056] Innovatively, the three-chamber smelting furnace according to the present invention achieves the above-mentioned objectives; such furnaces are indeed remarkably effective and efficient in treating aluminum scrap contaminated with volatile organic compounds.

[0057] in this regard, Figure 3 The table in the table, including some experimental data and some data from mathematical models, shows the specific consumption of natural gas and oxygen in the smelting step for three types of smelting furnaces: existing technology furnaces ( Figure 1 (Standard dual-cavity) and triple-cavity dual regenerator ( Figure 2 ).

[0058] The table emphasizes that for a standard dual-chamber furnace used to smelt aluminum scrap with a VOC content between 1% and 3%, the unit consumption of natural gas (NG) per ton of molten metal is 60 Nm³. 3 Furthermore, it does not consume oxygen. According to the present invention, the three-cavity double regenerative furnace, used for smelting aluminum scrap with a VOC content between 2% and 5%, consumes 34 to 17 Nm³ of natural gas (NG) per ton of molten metal. 3 Furthermore, the unit oxygen (O2) consumption per ton of molten metal is 7 to 30 Nm³. 3 .

[0059] Advantageously, the three-chamber furnace according to the invention further ensures that the waste is immersed in the molten aluminum pool after complete removal of volatile organic compounds. This eliminates the release of black smoke during the immersion of contaminated waste and significantly reduces the slag generated on the molten pool from organic components in the liquid phase, thereby increasing the furnace's metal production capacity, i.e., the ratio between the discharged aluminum and the fed aluminum.

[0060] Advantageously, the thermal regeneration system of the three-chamber furnace object of the present invention allows thermal energy to be transferred from the hot chamber to the cold chamber without transferring materials (flue gas or liquid) between the chambers.

[0061] Obviously, those skilled in the art can make improvements to the above-described dual-cavity furnace to meet emergency needs, and all such improvements are included within the scope of protection defined by the appended claims.

Claims

1. A smelting furnace (200) for smelting aluminum scrap (S), the smelting furnace comprising: - A cold chamber (222) is accessible from the main inlet (202) for introducing the waste (S), a dry base plate (112; 212) for supporting the waste (S) to be preheated, and a portion of a storage tank (214) for containing molten metal (B; Bc) up to the free surface; - At least one first hot chamber (224a) comprising another portion of the storage tank (214) for containing molten metal (B, Bha), and a second hot chamber (224b) comprising yet another portion of the storage tank (214) for containing molten metal (B, Bhb), the first hot chamber (224a) and the second hot chamber (224b) being separated from the cold chamber (222) above the free surface of the molten metal by a main partition wall (220), the main partition wall being provided with at least one first opening (226a) for flue gas to flow from the cold chamber (222) to the first hot chamber (224a) and at least one second opening (226b) for flue gas to flow from the cold chamber (222) to the second hot chamber (224b). - At least one regenerative burner assembly (228) comprising accumulation structures (228a', 228b') and configured to perform combustion in the first hot chamber (224a) and the second hot chamber (224b); - At least one heat storage body assembly (230) includes storage structures (230a', 230b') and is configured to draw flue gas from the first hot chamber (224a) and the second hot chamber (224b), heat the storage structures (230a', 230b') through the flue gas, and introduce heated air from the storage structures (230a', 230b') into the cold chamber (222).

2. The smelting furnace (200) according to claim 1, comprising at least one additional burner (240) adapted to operate in the cold chamber (222), the at least one additional burner preferably disposed on the top plate of the cold chamber (222).

3. The smelting furnace (200) according to claim 1 or 2, comprising at least one additional burner (241a, 241b) adapted to operate in the at least one hot chamber (224a, 224b), the at least one additional burner preferably disposed on the top plate of the at least one hot chamber (224a, 224b).

4. The smelting furnace (200) according to any one of the preceding claims includes at least one lance assembly (250a, 250b) configured to introduce oxygen into the at least one hot chamber (224a, 224b).

5. The smelting furnace (200) according to any one of the preceding claims includes a flue gas outlet pipe (142) that operates in the at least one hot chamber (224a, 224b) for discharging at least a portion of the flue gas generated in the at least one hot chamber (224a, 224b) toward a flue gas treatment system.

6. The smelting furnace (200) according to any one of the preceding claims includes a flue gas outlet pipe (238) that operates in the cold chamber for discharging at least a portion of the flue gas generated in the cold chamber (222) toward a flue gas treatment system.

7. The smelting furnace (200) according to any one of the preceding claims, wherein, The first hot chamber (224a) and the second hot chamber (224b) extend from the main partition wall (220) to the bottom wall (206) and are spaced apart from each other above the free surface of the molten metal by a secondary partition wall (225).

8. The smelting furnace according to claim 1, wherein, The burner assembly (228) includes a first regenerative burner (228a) operating in the first hot chamber (224a) and a second regenerative burner (228b) operating in the second hot chamber (224b), which cooperate with each other.

9. The smelting furnace according to claim 8, wherein, The first burner (228a) is disposed on the bottom wall (206) of the first hot chamber (224a), and the second burner (228b) is disposed on the bottom wall (206) of the second hot chamber (224b).

10. The smelting furnace according to claim 1, wherein, The heat storage body assembly (230) includes a first heat storage body (230a) and a second heat storage body (230b), wherein The first heat storage body (230a) is connected to an air inlet pipe (232) and a first air outlet pipe (234a), the first air outlet pipe leading to the cold chamber (222) at the drying base plate (212), and connected to a first flue gas inlet pipe (236a) and a flue gas outlet pipe (238), the first flue gas inlet pipe drawing flue gas from the first hot chamber (224a), and - The second heat storage body (230b) is connected to an air inlet pipe (232) and a second air outlet pipe (234b), the second air outlet pipe leading to the cold chamber (222) at the drying base plate (212), and connected to a second flue gas inlet pipe (236b) and a flue gas outlet pipe (238), the second flue gas inlet pipe drawing flue gas from the second hot chamber (224b).

11. A method for operating a smelting furnace (200) for aluminum scrap (S), wherein, The furnace (200) includes a cold chamber (222) for containing waste (S), a first hot chamber (224a), and a second hot chamber (224b), and includes the following cyclic steps: -In the first operation step: i) Supplying the air to be heated to the previously heated accumulation structure (228a') of the first regenerative burner (228a), and conveying the heated air and combustible gas to the first burner (228a) for combustion in the first hot chamber (224a); ii) Supply the air to be heated to the previously heated storage structure (230a') of the first heat storage body (230a) and transfer the heated air to the cold chamber (222). iii) Extract flue gas from the second hot chamber (224b) to heat the accumulation structure (228b') of the second regenerative burner (228b); iv) Extract flue gas from the second hot chamber (224b) to heat the storage structure (230b') of the second heat storage body (230b); v) Allows flue gas to be transferred from the first hot chamber (224a) to the cold chamber (222), and from the cold chamber (222) to the second hot chamber (224b); -In the second operational step: i) Supplying the air to be heated to the previously heated accumulation structure (228b') of the second burner (228b), and conveying the heated air and combustible gas to the second burner (228b) for combustion in the second hot chamber (224b); ii) Supply the air to be heated to the previously heated storage structure (230b') of the second heat storage body (230b) and transfer the heated air to the cold chamber (222). iii) Extract flue gas from the first hot chamber (224a) to heat the accumulation structure (228a') of the first burner (228a); iv) Extract flue gas from the first hot chamber (224a) to heat the storage structure (230a') of the first heat storage body (230a); v) Allows flue gas to be transferred from the second hot chamber (224b) to the cold chamber (222), and from the cold chamber (222) to the first hot chamber (224).

12. The operating method according to claim 11, comprising the following steps: - In the first operational step, between step iv) and step v): (iva) supplies air and combustible gas to at least one additional burner (140) operating in the cold chamber (222).

13. The operating method according to claim 11 or 12, comprising the following steps: -In the first operational step, after step v): vi) Supply oxygen to an oxygen lance (250b) operating in the second hot chamber (224b) to burn off at least a portion of the flue gas entering the second hot chamber (224b).

14. The operating method according to any one of claims 11 to 13, comprising the following steps: -In the second operational step, after step v): vi) Supply oxygen to an oxygen lance (250a) operating in the first hot chamber (224a) to burn off at least a portion of the flue gas entering the first hot chamber (224a).

15. The operating method according to any one of claims 11 to 14, wherein, The waste (S) arranged in the cold chamber (222) includes separate waste portions (Psi, where i=1……n), and the waste portions are introduced into the cold chamber (222) from the external environment of the furnace in chronological order, with the first portion (Ps1) being the first waste portion introduced and the nth portion (Psn) being the last waste portion introduced.

16. The operating method according to any one of claims 11 to 15, wherein, The scrap (S) arranged in the cold chamber (222) includes separate scrap portions (Psi, where i=1……n), and the scrap portions are introduced into the molten metal pool (Bc) of the cold chamber (122; 222) in chronological order, with the first portion (Ps1) being the first scrap portion introduced and the nth portion (Psn) being the last scrap portion introduced.

17. A method for operating a smelting furnace (200) for aluminum scrap (S), wherein, The furnace (200) includes a cold chamber (222) for containing the waste (S) and at least one hot chamber (224a). The waste (S) arranged in the cold chamber (222) includes a separate waste portion (Psi, where i=1……n), and The waste portion is introduced into the cold chamber (122; 222) from the external environment of the furnace in chronological order, with the first portion (Ps1) being the first waste portion introduced and the nth portion (Psn) being the last waste portion introduced. The waste portion is introduced into the molten metal pool (Bc) of the cold chamber (222) in chronological order, with the first portion (Ps1) being the first waste portion introduced and the nth portion (Psn) being the last waste portion introduced.

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