Immersion-based melting system and method for aluminum metals and alloys

Abstract

A melting furnace may include a feeding unit configured to supply solid metal; and a heating chamber for heating and maintaining the molten metal. The heating chamber may include a plurality of immersion heaters, wherein each immersion heater is immersed in the molten metal and heats the molten metal. The melting furnace may also include a pump configured to circulate molten metal from the heating chamber to the melting chamber; and a melting chamber configured to receive the solid metal from the feeding unit and the molten metal from the heating chamber, where the solid metal is submerged in the molten metal in the melting chamber and melted to produce a liquid metal. The liquid metal may be circulated from the melting chamber to the heating chamber.

Description

Cross-references to related applications

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 584,705, filed September 22, 2023, entitled “System and Method for Immersion Melting of Aluminum Metals and Alloys,” the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0002] Furnaces, such as induction furnaces, are commonly used to melt metals and metal alloys. Melting these materials is a common step in preparing for certain automotive applications, such as the high-pressure die casting of structural components. Induction furnaces use electrical energy for melting, but typically require water-cooled copper coils immersed in the molten metal, as well as high-voltage cables. Furthermore, induction furnaces involve highly complex facilities, resulting in a large footprint and requiring frequent maintenance. Summary of the Invention

[0003] According to one aspect of this disclosure, a melting furnace may include a feeding unit configured to supply solid metal; a heating chamber for heating and maintaining molten metal, wherein the heating chamber may include a plurality of immersion heaters, each of which may be immersed in and heat the molten metal; a pump configured to circulate the molten metal from the heating chamber to the melting chamber; and a melting chamber configured to receive the solid metal from the feeding unit and the molten metal from the heating chamber. The solid metal may be immersed in and melted in the molten metal within the melting chamber to produce liquid metal, and the liquid metal may be circulated from the melting chamber to the heating chamber.

[0004] In some examples, the feeding unit may include at least one of a walking feeder, a vibrating feeder, or a pusher unit that loads solid metal at a controlled speed. In some examples, the melting chamber may include a recessed molten pool section for mixing solid metal with molten metal. In some examples, the melting chamber may include one or more radiant top heaters configured to maintain the refractory material in the melting chamber above a predetermined temperature value. In some examples, the power of the one or more radiant top heaters may be between 15 kW and 90 kW, and the predetermined temperature value is 650°C.

[0005] In some examples, the melting chamber may include a first laser for monitoring the charge level of solid metal and a second laser for monitoring the height of liquid metal. In some examples, the melting chamber may include a ramp along which solid metal slides down and into a recessed molten pool. In some examples, the melting furnace may include a purification chamber for removing scum from the liquid metal via a porous plug before it enters the heating chamber. In some examples, the purification chamber may include one or more skimming dams configured to collect scum from the liquid metal. In some examples, the diameter of each of the plurality of immersion heaters may be between 75 mm and 135 mm; and the heating power of the plurality of immersion heaters may be between 1000 kW and 3000 kW.

[0006] According to another aspect of this disclosure, a method of operating a melting furnace may include: heating molten metal in a heating chamber via a plurality of immersion heaters that contact molten metal; pumping a portion of the molten metal from the heating chamber to a melting chamber; supplying solid metal into the melting chamber; melting the solid metal by immersing it in a portion of the molten metal in the melting chamber to produce a metal mixture; and circulating the metal mixture from the melting chamber back to the heating chamber.

[0007] In some examples, feeding solid metal into the melting chamber may include feeding the solid metal via at least one of a walking beam feeder, a vibrating feeder, or a pusher unit. In some examples, melting the solid metal may include immersing the solid metal in a portion of the molten metal within a recessed molten pool section of the melting chamber. In some examples, the method may include heating the melting chamber via one or more radiant top heaters to maintain the refractory material of the melting chamber above a predetermined temperature value. In some examples, the power of the one or more radiant top heaters may be between 15 kW and 90 kW, and the predetermined temperature value is 650°C.

[0008] In some examples, the method may include monitoring the charge level of the solid metal via a first laser and monitoring the height of the metal mixture via a second laser. In some examples, feeding the solid metal into the melting chamber may include allowing the solid metal to slide down a ramp and into a recessed molten pool. In some examples, the method may include filtering the metal mixture before it enters the heating chamber. In some examples, filtering the metal mixture may include degassing the metal mixture via one or more porous plugs and collecting slag from the metal mixture via one or more skimming dams. In some examples, the diameter of each of the plurality of immersion heaters may be between 75 mm and 135 mm; and the heating power of the plurality of immersion heaters may be between 1000 kW and 3000 kW. Attached Figure Description

[0009] The various objects, features and advantages of the disclosed subject matter can be more fully understood when considered in conjunction with the following accompanying drawings and with reference to the following detailed description of the subject matter, in which the same reference numerals identify the same elements.

[0010] Figure 1 This is based on some examples of immersion melting furnaces according to this disclosure.

[0011] Figure 2 Based on some examples from this disclosure Figure 1 The melting chamber based on an immersion melting furnace.

[0012] Figure 3 Based on some examples from this disclosure Figure 1 The heating chamber is based on an immersion melting furnace.

[0013] Figure 4 These are example methods for operating an immersion melting furnace, based on some examples of this disclosure.

[0014] The accompanying drawings are not necessarily drawn to scale, nor do they include all components of the system. Instead, the focus is generally on illustrating the concepts, structures, and techniques that this document seeks to protect. Detailed Implementation

[0015] The following detailed description is merely exemplary in nature and is not intended to limit the claimed invention or its application.

[0016] This disclosure provides examples of systems and methods for immersion melting of aluminum metal and alloys, such as via electrically powered immersion melting furnaces. The disclosed furnaces utilize various electrically powered immersion heaters operating on the principle of resistance heating to heat and maintain a molten pool of liquid metal (such as aluminum or other alloys). The liquid metal can be circulated to a separate chamber that receives the solid metal to be melted. The liquid metal surrounds and melts the solid metal, and the resulting mixture can be circulated back to the original chamber for further heating via the immersion heater. The disclosed examples offer various benefits, such as the ability to operate without process cooling water or other complex utilities. Furthermore, the disclosed furnaces have a more compact footprint than induction furnaces and require less maintenance. In some examples, the disclosed furnaces can melt up to three to ten metric tons of aluminum per hour. Additionally, the configuration of the disclosed furnaces facilitates easy cleaning and slag removal, which in turn increases the unit's lifespan and the quality of the metal produced. In some examples, the disclosed furnace can be operated together with an integrated insulation section to directly supply the casting process of large structural components.

[0017] In some examples, the disclosed immersion melting furnace can produce between approximately 3 and 10 tons (t / h) of liquid aluminum alloy when melting aluminum. Furthermore, the disclosed melting furnace can melt approximately 5500 kg / h of aluminum casting alloy and can be configured to hold between approximately 15 and 20 tons of liquid metal.

[0018] Figure 1 This describes an immersion melting furnace 100 according to some embodiments of this disclosure. In some embodiments, the furnace 100 may include a feeding unit 101 configured to load solid metal into the furnace 100. In some embodiments, the solid metal may be aluminum, although this is not limiting and is merely exemplary in nature. In some embodiments, the solid metal may be loaded in the form of ingots, blocks, and / or internal circulating scrap. Furthermore, the melting furnace 100 may include a buffer 102 to allow the furnace to be automatically fed, but with appropriate time buffering. In some embodiments, the buffer may be solid metal and may cause a buffer of approximately one hour. However, a one-hour buffer time is not necessary, and the length of the conveyor may vary based on the desired buffer time. In some embodiments, the width of the feeding unit 101 may be approximately 2.5 times the width of the loading block. In some embodiments, the feeding unit 101 may include a walking feeder, a vibrating feeder, or a pusher. In some embodiments, the feeding unit 101 may include a heavy-duty walking feeder having a metal loading capacity of twenty tons or more. In some embodiments, if the furnace is operating at a melting rate of about 5500 kg / h, the feeding unit 101 can load ingot bundles with a width of about 700 mm, and the conveyor width is 2 m.

[0019] Furthermore, furnace 100 may include a melting chamber 103 surrounded by refractory walls 109. In some embodiments, the refractory walls may refer to materials that generally resist decomposition under heat, pressure, and other extreme conditions. Moreover, these walls maintain their shape and strength even when exposed to such extreme conditions, such as those present inside the furnace. The melting chamber 103 may receive solid metal from the feeding unit 101. Additionally, the melting chamber 103 may receive liquid metal to form a molten pool and melt the solid metal. Regarding... Figure 2 Other details of the melting chamber 103 are discussed.

[0020] Furthermore, the melting furnace 100 may include a heating chamber 110 that can receive a mixture from a melting chamber 103, which may be surrounded by a refractory wall 109. This mixture may be generated by melting a solid metal ingot within a liquid metal in the melting chamber 103. In some embodiments, the mixture may be completely liquid, although this is not necessarily required and may not always occur. In other words, the entire solid metal does not necessarily become liquid in the melting chamber 103. In some embodiments, the heating chamber 110 may include porous plugs 104a to 104c (referred to individually as "porous plug 104" or collectively as "porous plug 104"), which can cause scum to float from the mixture received in the melting chamber 103, as well as degassing. For example, the porous plug 104 may include ceramics, such as alumina ceramics, having a known or controlled porosity that enables and enhances gas flow. Other types of gas diffusers may also be used. In some embodiments, the porous plug 104 may force suspended scum and / or oxide film into a scum layer via flotation. Then, one or more skimming dams (see Figure 3 This can capture floating or sinking scum, which ensures that furnace 100 is easy to clean. In some embodiments, the area containing the porous plug 104 and the skimming dam can be referred to as a "cleaning section". In some embodiments, the length of each skimming dam can be approximately twice the radius of the flotation bubble reaching the surface of the liquid metal in the furnace.

[0021] In addition, the heating chamber 110 may include a plurality of immersion heaters 105. Each of the immersion heaters 105 may be immersed in liquid metal (or a mixture of liquid metal before complete melting) contained within the heating chamber 110. In some embodiments, there may be 26 immersion heaters 105, organized into groups of four to six elements. In some embodiments, each group of immersion heaters 105 may be connected to a removable cover that can be raised for purging. In some embodiments, the heating chamber 110 may include a transfer pump 106 configured to circulate liquid metal around the heating chamber 110. In some embodiments, the transfer pump 106 may be a mechanical pump or an induction pump. In some embodiments, the heating chamber 110 may also include a pump 108 configured to pump liquid metal into a melting chamber 103 for melting purposes.

[0022] In some embodiments, furnace 100 may include a holding section 112. In some embodiments, the holding section 112 may be configured to directly supply metal to a casting process for large structural components. In some embodiments, the holding section 112 may include a height pump and degassers 107a to 107b, and a transfer pump 111 that can pump liquid metal for the casting process, such as pumping it to a subsequent furnace. In some embodiments, the holding section 112 may have a capacity of about 15 tons of metal contents and may be configured to receive 2750 kg every thirty minutes. Furthermore, the holding section 112 may be configured to maintain the temperature of the received metal at a constant level of about twelve degrees Celsius for one hour.

[0023] Figure 2 It is from some embodiments of this disclosure Figure 1 The melting chamber 103 is based on an immersion melting furnace. Figure 2 The view can be taken from Figure 1 The AA cross section. The melting chamber 103 can receive aluminum blocks at different stages 201a to 201d from the feeding unit 101 via a buffer 102. In some embodiments, the melting chamber 103 may include a swing door 202 that can be opened during melting mode and closed in standby mode to retain heat within the melting chamber 103. In some embodiments, the aluminum block 201 can slide down a ramp into a molten pool 208 of liquid metal. The liquid metal in the molten pool 208 may have been contained in the heating chamber 110. Figure 1 Pump 108 circulates the molten metal into the melting chamber 103. In some embodiments, the molten metal in the pool 208 can be maintained at a height 203 in standby mode and at a second height 204 in melting mode. Furthermore, the melting chamber 103 may include a door 205 that allows access to the pool 208 for purification purposes. In some embodiments, the melting chamber 103 may include one or more radiant top heaters (e.g., resistance heaters) 206 configured to heat the melting chamber 103 to maintain a predefined temperature level, such as 650°C. In some embodiments, the power output of each of the radiant heaters 206 may be between approximately 15 kW and 90 kW. In some embodiments, adding heat to the system via the radiant heaters 206 can help reduce the risk of moisture in the metal as the aluminum block 201 slides down the ramp. In some embodiments, the melting chamber 103 may also include a fan (not shown) for convective heating. Additionally, the melting chamber 103 may include one or more lasers 207 for monitoring various characteristics of the melting process. For example, when the aluminum block 201 enters the melting chamber 103, the first laser can monitor the loading level of the aluminum block 201, and the second laser can monitor the height of the liquid metal mixture in the molten pool 208.

[0024] Figure 3 It is from some embodiments of this disclosure Figure 1 Heating chamber 110 based on immersion melting furnace. Figure 3 The view can be taken from Figure 1 The cross-section of BB. For example... Figure 2 As discussed herein, melting chamber 103 may include levels 203 and 204 of liquid metal. Heating chamber 110 may include porous plugs 104a to 104c and multiple immersion heaters 105, as described in [the relevant section]. Figure 1 As discussed above. Furthermore, the heating chamber 110 may include two skimming dams 301a to 301b to capture floating or sinking scum within the liquid metal. In some embodiments, the heating chamber 110 may include an inclined bottom plate 302 to collect sediment and facilitate a simple discharge procedure. In some embodiments, the heating chamber 110 may maintain the liquid metal at a level between levels 303 and 304. In other words, the heating chamber 110 may utilize a minimum metal level and a maximum metal level.

[0025] Figure 4 This is an example method 400 for operating a submersion-based melting furnace according to some embodiments of the present disclosure. In block 401, a pool of liquid metal is maintained in heating chamber 110 using a plurality of submersion heaters 105. In block 402, at least a portion of the liquid metal is pumped from heating chamber 110 to melting chamber 103, such as via a mechanical pump or induction pump (pump 108). In block 403, feeding unit 101 loads solid metal into melting chamber 103. In some embodiments, the solid metal may be supplied in the form of ingots, blocks, or scrap metal. In some embodiments, the solid metal may be supplied at a controlled speed via a walking feeder, vibrating feeder, or pusher unit. In some embodiments, the solid metal may slide down a ramp (i.e., via gravity) into the pool of liquid metal, causing the solid metal to melt. In other words, the solid metal is immersed in the liquid metal, causing the solid metal to heat up until it begins to melt. This produces a metal mixture.

[0026] In block 404, the metal mixture is pumped from the melting chamber 103 to the purification section. Once in the purification section, the mixture is purified in block 405. In some embodiments, purifying the mixture may include degassing the metal mixture via one or more porous plugs 104 and collecting scum from the metal mixture via one or more skimming dams. In block 406, the purified mixture is further pumped to the heating chamber 110, for example, to apply additional heating via an immersion heater 105. Exemplary aspect.

[0027] The following exemplary embodiments are provided, and their numbers should not be interpreted as specifying an importance level:

[0028] Aspect 1 provides a melting furnace, the melting furnace comprising: A feeding unit configured to supply solid metal; A heating chamber for heating and maintaining molten metal, the heating chamber comprising a plurality of immersion heaters, each of which is immersed in and heats the molten metal; A pump configured to circulate molten metal from a heating chamber to a melting chamber; and The melting chamber is configured to receive solid metal from the feeding unit and molten metal from the heating chamber, wherein the solid metal is immersed in the molten metal within the melting chamber and melts to produce liquid metal; The liquid metal circulates from the melting chamber to the heating chamber.

[0029] Aspect 2 provides the melting furnace of aspect 1, wherein the feeding unit includes at least one of a walking feeder, a vibrating feeder, or a pusher unit that loads solid metal at a controlled speed.

[0030] Aspect 3 provides a melting furnace of either Aspect 1 or Aspect 2, wherein the melting chamber includes a recessed molten pool section for mixing solid metal in molten metal.

[0031] Aspect 4 provides the melting furnace of aspect 3, wherein the melting chamber includes one or more radiant top heaters configured to maintain the refractory properties of the melting chamber above a predefined temperature value.

[0032] Aspect 5 provides the melting furnace of Aspect 4, wherein one or more radiant furnace top heaters have a power between 15 kW and 90 kW and a predefined temperature value of 650°C.

[0033] Aspect 6 provides a melting furnace according to any one of Aspects 3 to 5, wherein the melting chamber includes: A first laser, used to monitor the charge level of solid metal; and A second laser is used to monitor the height of the liquid metal.

[0034] Aspect 7 provides a melting furnace of any one of aspects 3 to 6, wherein the melting chamber includes a ramp, wherein solid metal slides down the ramp and into a recessed molten pool.

[0035] Aspect 8 provides a melting furnace according to any one of Aspects 1 to 7, the melting furnace including a purification chamber for removing slag from the liquid metal via a porous plug before the liquid metal enters the heating chamber.

[0036] Aspect 9 provides the melting furnace of aspect 8, wherein the purification chamber includes one or more skimming dams configured to collect scum from the liquid metal.

[0037] Aspect 10 provides a melting furnace for any one of aspects 1 to 9, wherein: The diameter of each of the multiple immersion heaters is between 75 mm and 135 mm; and The heating power of the multiple immersion heaters ranges from 1,000 kW to 3,000 kW.

[0038] Aspect 11 provides a method for operating a melting furnace, the method comprising: Molten metal is heated in a heating chamber via multiple immersion heaters that come into contact with it. A portion of the molten metal is pumped from the heating chamber to the melting chamber; Solid metal is fed into the melting chamber. A metal mixture is produced by immersing a portion of solid metal in molten metal within a melting chamber to melt the solid metal; and The metal mixture is circulated from the melting chamber to the heating chamber.

[0039] Aspect 12 provides the method of aspect 11, wherein feeding solid metal into a melting chamber includes feeding solid metal via at least one of a walking feeder, a vibrating feeder, or a pusher unit.

[0040] Aspect 13 provides a method of either aspect 11 or 12, wherein melting solid metal includes immersing the solid metal in a portion of molten metal in a recessed molten pool section of a melting chamber.

[0041] Aspect 14 provides the method of aspect 13, which includes heating the melting chamber via one or more radiant furnace top heaters to maintain the refractory material of the melting chamber above a predefined temperature value.

[0042] Aspect 15 provides the method of aspect 14, wherein one or more radiant furnace top heaters have a power between 15 kW and 90 kW and a predefined temperature value of 650°C.

[0043] Aspect 16 provides a method of any one of aspects 13 to 15, the method comprising: The loading level of solid metal is monitored via a first laser; and The height of the metal mixture is monitored via a second laser.

[0044] Aspect 17 provides a method of any one of aspects 13 to 16, wherein feeding solid metal into a melting chamber includes causing the solid metal to slide down a ramp and into a recessed molten pool.

[0045] Aspect 18 provides a method of any one of aspects 11 to 17, the method comprising filtering the metal mixture before it enters the heating chamber.

[0046] Aspect 19 provides the method of aspect 18, wherein filtering a metal mixture includes: Degassing of a metal mixture via one or more porous plugs; and Scum is collected from the metal mixture via one or more skimming dams.

[0047] Aspect 20 provides a method for any one of aspects 11 to 19, wherein: The diameter of each of the multiple immersion heaters is between 75 mm and 135 mm; and The heating power of the multiple immersion heaters ranges from 1,000 kW to 3,000 kW.

[0048] While various embodiments have been described above, it should be understood that they are presented by way of example and not limitation. It will be apparent to those skilled in the art (one or more) that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. Indeed, after reading the above description, those skilled in the art (one or more) will understand how to implement alternative embodiments. For example, other steps may be provided, or steps may be eliminated from the described process, and other components may be added to or removed from the described system. Therefore, other implementations are also within the scope of the following claims.

[0049] Furthermore, it should be understood that any accompanying drawings highlighting functionality and advantages are presented for illustrative purposes only. The disclosed methods and systems are each sufficiently flexible and configurable that they can be utilized in ways other than those shown.

[0050] Although the term "at least one" is frequently used in the specification, claims and drawings, the terms "a," "an," "the," "the," etc., also mean "at least one" or "the at least one" in the specification, claims and drawings.

Claims

1. A melting furnace, comprising: A feeding unit configured to supply solid metal; A heating chamber for heating and maintaining molten metal, the heating chamber comprising a plurality of immersion heaters, wherein each immersion heater is immersed in the molten metal and heats the molten metal; A pump, configured to circulate the molten metal from the heating chamber to the melting chamber, and The melting chamber is configured to receive the solid metal from the feeding unit and the molten metal from the heating chamber, wherein the solid metal is immersed in the molten metal within the melting chamber and melts to produce liquid metal; The liquid metal is circulated from the melting chamber to the heating chamber.

2. The melting furnace according to claim 1, wherein the feeding unit comprises at least one of a walking feeder, a vibrating feeder, or a pusher unit that loads the solid metal at a controlled speed.

3. The melting furnace according to claim 1, wherein the melting chamber includes a recessed molten pool section for mixing the solid metal in the molten metal.

4. The melting furnace of claim 3, wherein the melting chamber comprises one or more radiant top heaters configured to maintain the refractory material of the melting chamber above a predetermined temperature value.

5. The melting furnace according to claim 4, wherein the power of the one or more radiant furnace top heaters is between 15 kW and 90 kW, and the predefined temperature value is 650°C.

6. The melting furnace according to claim 3, wherein the melting chamber comprises: A first laser is used to monitor the charge level of the solid metal. as well as A second laser is used to monitor the height of the liquid metal.

7. The melting furnace of claim 3, wherein the melting chamber includes a ramp, wherein the solid metal slides down the ramp and enters the recessed molten pool.

8. The melting furnace according to claim 1, wherein the melting furnace includes a purification chamber for removing slag from the liquid metal via a porous plug before the liquid metal enters the heating chamber.

9. The melting furnace of claim 8, wherein the purification chamber comprises one or more skimming dams configured to collect slag from the liquid metal.

10. The melting furnace according to claim 1, wherein: The diameter of each of the plurality of immersion heaters is between 75 mm and 135 mm; and The heating power of the plurality of immersion heaters is between 1,000 kW and 3,000 kW.

11. A method of operating a melting furnace, comprising: The molten metal is heated in a heating chamber via multiple immersion heaters that contact the molten metal. A portion of the molten metal is pumped from the heating chamber to the melting chamber; Solid metal is supplied to the melting chamber; The solid metal is melted by immersing it in the portion of the molten metal in the melting chamber to produce a metal mixture; and The metal mixture is circulated from the melting chamber to the heating chamber.

12. The method of claim 11, wherein feeding the solid metal into the melting chamber comprises feeding the solid metal via at least one of a walking feeder, a vibrating feeder, or a pusher unit.

13. The method of claim 11, wherein melting the solid metal comprises immersing the solid metal in a portion of the molten metal in a recessed molten pool section of the melting chamber.

14. The method of claim 13, further comprising heating the melting chamber via one or more radiant furnace top heaters to maintain the refractory material of the melting chamber above a predetermined temperature value.

15. The method of claim 14, wherein the power of the one or more radiant furnace top heaters is between 15 kW and 90 kW, and the predefined temperature value is 650°C.

16. The method of claim 13, comprising: The charge level of the solid metal is monitored via a first laser; as well as The height of the metal mixture is monitored via a second laser.

17. The method of claim 13, wherein supplying the solid metal into the melting chamber comprises causing the solid metal to slide down a ramp and into the recessed molten pool.

18. The method of claim 11, further comprising filtering the metal mixture before it enters the heating chamber.

19. The method of claim 18, wherein filtering the metal mixture comprises: The metal mixture is degassed via one or more porous plugs; as well as Scum is collected from the metal mixture via one or more skimming dams.

20. The method of claim 11, wherein: The diameter of each of the plurality of immersion heaters is between 75 mm and 135 mm; and The heating power of the plurality of immersion heaters is between 1,000 kW and 3,000 kW.

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