Device and method for preparing high-purity aluminum from aluminum ash

Abstract

The invention discloses a device for preparing high-purity aluminum from aluminum ash and a preparation method, and belongs to the technical field of high-purity aluminum preparation. A device for preparing high-purity aluminum through aluminum ash comprises a shell, microwave generators are installed on the two sides of the upper portion of a quartz ceramic plate, water-cooling copper crucibles are installed below two water-cooling butterfly valves, electromagnetic generators are installed on the two sides of the lower end of the shell, and traveling wave electromagnetic coils are installed outside an inner crucible and the water-cooling copper crucibles. The device solves the problems that an existing high-purity aluminum preparation device is relatively complex in process and cannot guarantee the preparation efficiency due to the number of devices and material transfer, pretreatment, melting and refining are integrated into one device through the shell, dangerous aluminum ash is directly used as a raw material, high-purity aluminum ingots are finally produced, and the production cost is reduced. High-value utilization of hazardous wastes is realized, the process flow is greatly shortened, oxidation and heat loss caused by material transfer are reduced, and the purification effect is improved.

Description

Technical Field

[0001] This invention relates to the field of high-purity aluminum preparation technology, specifically to an apparatus and method for preparing high-purity aluminum using aluminum ash slag. Background Technology

[0002] Aluminum ash slag is a byproduct of the aluminum and aluminum alloy smelting and casting process. The preparation of high-purity aluminum using aluminum ash slag is a complex process involving multiple steps and corresponding equipment.

[0003] Chinese Patent No. CN106929688B discloses an apparatus and method for preparing high-purity aluminum using aluminum ash slag. The apparatus for preparing high-purity aluminum using aluminum ash slag includes a double-layer liquid aluminum electrolytic cell (2) using aluminum ash slag as raw material, a triple-layer liquid aluminum electrolytic cell (3) using the electrolytic products from the apparatus (2) as raw material, and a partition wall (5) separating the double-layer liquid electrolytic zone and the triple-layer liquid electrolytic zone. The method adopts a combined structure of a double-layer liquid aluminum electrolytic cell and a triple-layer liquid aluminum electrolytic cell. The aluminum liquid zone and the electrolyte zone of the double-layer liquid and triple-layer liquid electrolytic cells are connected by a connecting channel. The aluminum ash slag is electrolyzed by the double-layer liquid, and the electrolytic products of the aluminum ash slag are electrolyzed by the triple-layer liquid. The aluminum, alumina, and salt in the aluminum ash slag are recovered to obtain high-purity electrolytic aluminum liquid and clean salts.

[0004] In actual use, the high-purity aluminum preparation device mentioned in the above patent has a relatively complex process due to the number of devices and material transfer, which makes it impossible to guarantee the preparation efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for preparing high-purity aluminum using aluminum ash slag, which solves the problem that the high-purity aluminum preparation apparatus mentioned in the background art is relatively complex in actual use due to the number of equipment and material transfer, and cannot guarantee the preparation efficiency.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an apparatus for preparing high-purity aluminum using aluminum ash slag, comprising a shell, a quartz ceramic plate installed in the middle of the shell, microwave generators installed on both sides above the quartz ceramic plate, two water-cooled butterfly valves disposed inside the quartz ceramic plate, a water-cooled copper crucible installed below each of the two water-cooled butterfly valves, electromagnetic generators installed on both sides of the lower end of the shell, an inner crucible disposed inside the water-cooled copper crucible, and traveling wave electromagnetic coils installed outside both the inner crucible and the water-cooled copper crucible. The generator is electrically connected to the traveling wave electromagnetic coil, integrating pretreatment, melting, and refining into a single device through the housing. It directly uses hazardous aluminum ash slag as raw material to ultimately produce high-purity aluminum ingots, realizing the high-value utilization of hazardous waste. This greatly shortens the process flow, reduces oxidation and heat loss caused by material transfer, and fully leverages the advantages of microwave heating and selective activation, as well as the forced convection and efficient condensation advantages of electromagnetic stirring. This improves the purification effect. Microwave heating has high energy utilization, electromagnetic stirring is contactless and pollution-free, and the entire system is closed and environmentally friendly, maintaining efficient preparation work while being green and environmentally friendly.

[0007] Preferably, a support frame is installed on the outside of the housing, and the support frame is connected to the housing and the microwave generator by fixing screws. The microwave generator extends into the housing and is sealed to the housing.

[0008] Preferably, the quartz ceramic plate is fixedly connected to the housing, and the edge of the quartz ceramic plate is sealed to the inner wall of the housing. The quartz ceramic plate is provided with two integrally formed feed ports, which are sealed to the water-cooled butterfly valve. A stepper motor is installed on one side of the housing. A magnetic brake and a reducer are installed at one end of the stepper motor shaft. A rotating shaft is connected to one end of the magnetic brake and the reducer. The rotating shaft passes through the water-cooled butterfly valve and is fixedly connected to the water-cooled butterfly valve by a locking sleeve. A bearing seat is installed outside the housing, and the rotating shaft is rotatably connected to the housing through the bearing seat.

[0009] Preferably, the bottom of the housing is provided with an inspection port, the upper end of the housing is provided with an upper sealing cover plate, a folding plate is welded to one end of the upper sealing cover plate, a hydraulic hinge is installed between the folding plate and the housing, and the upper sealing cover plate is movably connected to one end of the housing through the hydraulic hinge.

[0010] Preferably, a connecting ear is installed at the other end of the upper sealing cover, and an electric cylinder is installed on one side of the upper sealing cover. The upper end of the electric cylinder is hinged to the connecting ear, and the lower end of the electric cylinder is fixedly connected to the support frame. The electric cylinder extends and retracts to open and close the upper sealing cover.

[0011] Preferably, a filter smoke pipe is installed at the upper end of the upper sealing cover, and an exhaust fan is installed in the middle of the filter smoke pipe. The filter smoke pipe extends into the housing and is fixedly connected to the upper sealing cover. The upper sealing cover and the housing are sealed together by a sealing gasket. Two mode stirrers are installed on the upper sealing cover. Both mode stirrers are used to extend into the housing to disperse the standing waves of microwaves. The mode stirrer includes a stirrer and a motor. The stirrer rotates slowly under the drive of the motor. By continuously changing the electromagnetic field distribution in the cavity, the standing waves of microwaves are dispersed, thereby achieving uniform heating of the material as a whole.

[0012] Preferably, the microwave generator is equipped with an external ventilation valve and an internal air inlet pipe for introducing the gas required for the high-purity aluminum preparation reaction. A multi-source magnetron plate is installed inside the microwave generator, and a pulse magnetron is installed within the multi-source magnetron plate. For materials with low thermal conductivity, such as aluminum ash slag, the heating efficiency is significantly improved. The heating effect of microwaves on different substances depends on their dielectric properties. Non-metallic components such as alumina and aluminum nitride in aluminum ash slag generally absorb microwaves more readily, while metallic aluminum has relatively weak microwave absorption capacity. Selective microwave heating allows impurities such as aluminum nitride to quickly reach the reaction temperature. When air is introduced, the reaction can be efficiently carried out and harmlessly disposed of, achieving a green and environmentally friendly high-purity aluminum preparation effect.

[0013] Preferably, a support base is installed at the bottom of the shell, two cooling covers are installed on the top of the shell, positioning frames are installed on both sides of the lower end of the inner crucible, a hydraulic cylinder is installed between the positioning frame and the support base, and a hydraulic oil pump is installed below the hydraulic cylinder.

[0014] Preferably, an electrical box is installed at the upper end of the support base, and a cooling water tank is installed inside the support base. A circulating water pipe is installed inside the cooling cover. The circulating water pipe is connected to the cooling water tank via a water pump. A radiator is installed outside the cooling water tank. The inner crucible descends into the cooling cover and is cooled by water cooling through the circulating water pipe. A feeding hopper is provided at the lower end of the inner crucible, and a high-purity aluminum feeding port is provided at the lower end of the support base. The position of the high-purity aluminum feeding port corresponds to the position of the feeding hopper, and a valve is provided at the bottom of the feeding hopper.

[0015] A method for preparing high-purity aluminum using aluminum ash slag includes the following steps: Step 1: Extend the electric cylinder to open the upper sealing cover, add aluminum ash and flux into the shell, then retract the electric cylinder to seal the upper sealing cover and the shell. Step 2: Turn on the microwave generator. The aluminum ash and flux above the quartz ceramic plate are heated by microwave through the multi-source magnetron plate and stirred by the mode stirrer to change the electromagnetic field distribution in the cavity, disperse the standing waves of the microwaves, and heat evenly. Step 3: Nitrogen and argon are introduced through the ventilation valve and inlet pipe as a protective atmosphere to prevent the aluminum liquid from oxidizing. Under the inert and reactive gas conditions, the aluminum ash slag is efficiently denitrified, salts are evaporated, and metal oxides are reduced to convert it into activated aluminum material. The activated aluminum material is melted under the protective atmosphere to form the initial aluminum liquid. The exhaust gas is discharged through the filter pipe and exhaust fan. Step 4: Drive the rotating shaft to rotate using a stepper motor, open the water-cooled butterfly valve, and slowly guide the molten aluminum into the water-cooled copper crucible. After the molten aluminum is discharged, close the water-cooled butterfly valve and clean the slag floating on the surface of the molten aluminum. Step 5: Start the electromagnetic generator. By controlling the phase and frequency of the three-phase AC power, the traveling wave electromagnetic coil generates a traveling magnetic field, which drives the molten aluminum to perform horizontal rotation, vertical or combined motion, and forcefully pushes impurities towards the solidification front. Step 6: The aluminum liquid solidifies layer by layer from the bottom up. At the solidification interface, the electromagnetic stirrer continues to work, constantly sweeping away the precipitated impurities from the solidification interface and enriching them in the remaining liquid phase. Step 7: Retract the hydraulic cylinder to lower the inner crucible. During the descent, the surface of the inner crucible is cooled by the cooling hood. The solidified high-purity aluminum ingot is discharged through the feeding hopper and the high-purity aluminum discharge port.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes a microwave generator to heat aluminum ash slag by absorbing microwave energy and converting it into heat energy. The oxides and nitrides in the aluminum ash slag will vibrate and generate heat through friction in the microwave high-frequency electromagnetic field, achieving simultaneous heating of the entire material. This avoids the problems of low thermal efficiency and slow temperature rise of traditional external heating methods. For materials with low thermal conductivity such as aluminum ash slag, the improvement in heating efficiency is particularly significant. The heating effect of microwaves on different substances depends on their dielectric properties. Non-metallic components such as aluminum oxide and aluminum nitride in aluminum ash slag are usually more likely to absorb microwaves, while the microwave absorption capacity of metallic aluminum is relatively weak. Selective microwave heating allows impurities such as aluminum nitride to quickly reach the reaction temperature. When air is introduced, it can be efficiently reacted and harmlessly disposed of, achieving a green and environmentally friendly high-purity aluminum preparation effect.

[0017] 2. This invention, by installing a traveling wave electromagnetic coil outside the molten aluminum and applying an alternating electromagnetic field, induces a current within the melt. This induced current interacts with the magnetic field to generate a Lorentz force, driving the melt's movement. Compared to mechanical stirring, the powerful flow generated by the traveling wave electromagnetic coil continuously disperses the boundary layer liquid rich in impurities, mixing it with the main melt. This prevents impurities from accumulating at the interface or even being re-entrained into the solidified crystals, thus greatly improving purification efficiency. By adjusting the magnitude and frequency of the electromagnetic generator current, the stirring force can be precisely controlled, from gentle mixing to... Vigorous turbulence and non-contact electromagnetic stirring avoid contamination of the molten aluminum and prevent gas entrapment, making it particularly suitable for the preparation of high-purity materials. The melt flow makes the temperature and composition more uniform, avoiding local overheating or component segregation. Strong stirring helps the reactants mix and the products diffuse, and enables the fine aluminum droplets to collide, aggregate, and settle more effectively, thereby improving the aluminum recovery rate. During the subsequent solidification process, the flow breaks up the dendrites formed during solidification and promotes the formation of equiaxed crystals, thereby refining the grain structure and improving the mechanical properties of the final high-purity aluminum ingot.

[0018] 3. This invention integrates pretreatment, melting, and refining into a single device through a shell, directly using hazardous aluminum ash slag as raw material to ultimately produce high-purity aluminum ingots. This achieves high-value utilization of hazardous waste, greatly shortens the process flow, reduces oxidation and heat loss caused by material transfer, and fully leverages the advantages of microwave heating and selective activation, as well as the forced convection and efficient condensation advantages of electromagnetic stirring. This improves the purification effect, with high energy utilization of microwave heating, non-contact pollution from electromagnetic stirring, and a closed and environmentally friendly system that maintains efficient preparation work while being green and environmentally friendly. Attached Figure Description

[0019] Figure 1 This is an isometric view of the front view of the present invention; Figure 2 For the present invention Figure 1 Enlarged view of a portion of area A in the middle; Figure 3 This is an isometric view of the side view of the present invention; Figure 4 This is an axonometric view of the invention from below; Figure 5 This is an isometric view of the casing of the present invention from top view; Figure 6 For the present invention Figure 5 Enlarged view of a section in area B; Figure 7 This is a top-view axonometric view of the housing after the quartz ceramic plate of the present invention has been disassembled; Figure 8 This is an isometric view of the front view of the water-cooled copper crucible of the present invention; Figure 9 This is a diagram showing the internal structure of the support base of the present invention.

[0020] In the diagram: 1. Shell; 101. Support frame; 102. Quartz ceramic plate; 103. Feed inlet; 104. Inspection port; 2. Upper sealing cover; 201. Exhaust fan; 202. Filter pipe; 203. Electric cylinder; 204. Folding plate; 205. Hydraulic hinge; 206. Connecting lug; 207. Mode stirrer; 3. Microwave generator; 301. Air exchange valve; 302. Multi-source magnetron; 303. Air inlet pipe; 4. Electromagnetic generator; 401. Traveling wave electromagnetic generator. 5. Coil; 6. Support base; 7. Cooling cover; 8. Electrical box; 9. Hydraulic cylinder; 10. High-purity aluminum discharge port; 11. Circulating water pipe; 12. Cooling water tank; 23. Radiator; 34. Hydraulic oil pump; 55. Stepper motor; 66. Side magnetic brake; 77. Reducer; 88. Bearing seat; 99. Water-cooled butterfly valve; 100. Rotary shaft; 11. Water-cooled copper crucible; 12. Inner crucible; 13. Discharge hopper; 14. Positioning frame. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] To address the issue of poor heating efficiency and slow temperature rise of aluminum ash slag, a material with low thermal conductivity, in existing high-purity aluminum production equipment during practical use, please refer to... Figure 1 - Figure 6 This embodiment provides the following technical solution: This embodiment of an apparatus for preparing high-purity aluminum using aluminum ash slag includes a shell 1, with a quartz ceramic plate 102 installed in the middle of the shell 1. Microwave generators 3 are installed on both sides above the quartz ceramic plate 102. Heating is achieved by the aluminum ash slag absorbing microwave energy and converting it into heat energy through the microwave generators 3. The oxides and nitrides in the aluminum ash slag will vibrate and rub against each other to generate heat in the microwave high-frequency electromagnetic field, so as to achieve simultaneous heating of the entire material. This avoids the problems of low thermal efficiency and slow heating of traditional external heating methods. The outer side of the housing 1 is equipped with a support frame 101, which is connected to the housing 1 and the microwave generator 3 by fixing screws. The microwave generator 3 extends into the housing 1 and is sealed to the housing 1.

[0023] In addition, a filter smoke pipe 202 is installed at the upper end of the upper sealing cover plate 2, and an exhaust fan 201 is installed in the middle of the filter smoke pipe 202. The filter smoke pipe 202 extends into the interior of the housing 1 and is fixedly connected to the upper sealing cover plate 2. The upper sealing cover plate 2 and the housing 1 are sealed together by a sealing gasket. Two mode stirrers 207 are installed on the upper sealing cover plate 2. Both mode stirrers 207 are used to extend into the interior of the housing 1 to disperse the standing waves of microwaves. The mode stirrer 207 includes a stirrer and a motor. The stirrer rotates slowly under the drive of the motor. By continuously changing the electromagnetic field distribution in the cavity, the standing waves of microwaves are dispersed, thereby achieving uniform heating of the material as a whole.

[0024] Furthermore, an air exchange valve 301 is installed on the outside of the microwave generator 3, and an air inlet pipe 303 is also installed inside the microwave generator 3. The air inlet pipe 303 is used to introduce the gas required for the high-purity aluminum preparation reaction. A multi-source magnetron plate 302 is installed on the inside of the microwave generator 3. A pulse magnetron is installed inside the multi-source magnetron plate 302. For materials with low thermal conductivity such as aluminum ash slag, the heating efficiency is significantly improved. The heating effect of microwaves on different substances depends on their dielectric properties. Non-metallic components such as aluminum oxide and aluminum nitride in aluminum ash slag are usually more likely to absorb microwaves, while the microwave absorption capacity of metallic aluminum is relatively weak. Selective microwave heating allows impurities such as aluminum nitride to quickly reach the reaction temperature. When air is introduced, it can be efficiently generated and harmlessly disposed of, which can achieve the green and environmentally friendly high-purity aluminum preparation effect.

[0025] Specifically, heating via microwave generator 3 relies on the aluminum ash slag itself absorbing microwave energy and converting it into heat energy. The oxides and nitrides in the aluminum ash slag will violently oscillate and generate heat through friction in the microwave high-frequency electromagnetic field, achieving simultaneous heating of the entire material. This avoids the problems of low thermal efficiency and slow temperature rise of traditional external heating methods. For materials with low thermal conductivity such as aluminum ash slag, the improvement in heating efficiency is particularly significant. The heating effect of microwaves on different substances depends on their dielectric properties. Non-metallic components such as aluminum oxide and aluminum nitride in aluminum ash slag are usually more likely to absorb microwaves, while the microwave absorption capacity of metallic aluminum is relatively weak. Selective microwave heating allows impurities such as aluminum nitride to quickly reach the reaction temperature. When air is introduced, it can be efficiently reacted and harmlessly disposed of, achieving a green and environmentally friendly high-purity aluminum preparation effect.

[0026] To address the problems of existing high-purity aluminum preparation equipment, such as relatively complex processes due to the number of devices and material transfer, low purification efficiency, and impurity accumulation at interfaces or even re-entry into solidified crystals, please refer to [the relevant documentation / reference]. Figure 1 - Figure 2 , Figure 7 - Figure 9 This embodiment provides the following technical solution: In this embodiment, the quartz ceramic plate 102 is internally equipped with two water-cooled butterfly valves 604. A water-cooled copper crucible 7 is installed below each of the two water-cooled butterfly valves 604. Electromagnetic generators 4 are installed on both sides of the lower end of the shell 1. An inner crucible 701 is installed inside the water-cooled copper crucible 7. Traveling wave electromagnetic coils 401 are installed on the outside of both the inner crucible 701 and the water-cooled copper crucible 7. The electromagnetic generators 4 are electrically connected to the traveling wave electromagnetic coils 401. When the traveling wave electromagnetic coils 401 are installed outside the aluminum liquid and an alternating electromagnetic field is applied, an induced current is generated in the melt. This induced current interacts with the magnetic field to generate a Lorentz force, which drives the melt to move. Compared with mechanical stirring, the strong flow generated by the traveling wave electromagnetic coils 401 can continuously blow away these boundary layer liquids rich in impurities and mix them with the main melt, preventing impurities from accumulating at the interface or even being re-rolled into the solidified crystals, thereby greatly improving the purification efficiency.

[0027] The bottom of the housing 1 is provided with an inspection port 104, and the upper end of the housing 1 is provided with an upper sealing cover 2. A folding plate 204 is welded to one end of the upper sealing cover 2. A hydraulic hinge 205 is installed between the folding plate 204 and the housing 1. The upper sealing cover 2 is movably connected to one end of the housing 1 through the hydraulic hinge 205.

[0028] In addition, a connecting ear 206 is installed at the other end of the upper sealing cover plate 2, and an electric cylinder 203 is installed on one side of the upper sealing cover plate 2. The upper end of the electric cylinder 203 is hinged to the connecting ear 206, and the lower end of the electric cylinder 203 is fixedly connected to the support frame 101. The telescopic electric cylinder 203 switches the upper sealing cover plate 2.

[0029] The shell 1 has a support base 5 installed at the bottom and two cooling covers 501 installed on the top. The inner crucible 701 has positioning frames 703 installed on both sides of its lower end. A hydraulic cylinder 503 is installed between the positioning frame 703 and the support base 5. A hydraulic oil pump 508 is installed below the hydraulic cylinder 503.

[0030] It should be noted that an electrical box 502 is installed on the upper end of the support base 5, and a cooling water tank 506 is installed inside the support base 5. A circulating water pipe 505 is installed inside the cooling cover 501. The circulating water pipe 505 is connected to the cooling water tank 506 via a water pump. A radiator 507 is installed on the outside of the cooling water tank 506. The inner crucible 701 descends into the cooling cover 501 and is cooled by the cooling water in the circulating water pipe 505. A feeding hopper 702 is installed at the lower end of the inner crucible 701, and a high-purity aluminum container is installed at the lower end of the support base 5. The high-purity aluminum discharge port 504 is located in a position corresponding to the discharge hopper 702. A valve is installed at the bottom of the discharge hopper 702. The aluminum liquid solidifies layer by layer from the bottom upwards. At the solidification interface, the electromagnetic stirrer works continuously to sweep away the precipitated impurities from the solidification interface and enrich them in the remaining liquid phase. The hydraulic cylinder 503 contracts, driving the inner crucible 701 to descend. During the descent, the surface of the inner crucible 701 is cooled by the cooling cover 501. The solidified high-purity aluminum ingot is discharged through the discharge hopper 702 and the high-purity aluminum discharge port 504.

[0031] The quartz ceramic plate 102 is fixedly connected to the housing 1, and the edge of the quartz ceramic plate 102 is sealed to the inner wall of the housing 1. Two integrally formed feed inlets 103 are provided on the quartz ceramic plate 102, and the feed inlets 103 are sealed to the water-cooled butterfly valve 604. A stepper motor 6 is installed on one side of the housing 1. A magnetic brake 601 and a reducer 602 are installed at one end of the motor shaft of the stepper motor 6. A rotating shaft 605 is connected to one end of the magnetic brake 601 and the reducer 602. The rotating shaft 605 passes through the water-cooled butterfly valve 604 and is fixedly connected to the water-cooled butterfly valve 604 by a locking sleeve. A bearing seat 6 is installed outside the housing 1. 03, and the rotating shaft 605 is rotatably connected to the housing 1 through the bearing seat 603. The pretreatment, melting and refining are integrated into one device through the housing 1. The hazardous aluminum ash slag is directly used as raw material to produce high-purity aluminum ingots. This realizes the high-value utilization of hazardous waste, greatly shortens the process flow, reduces oxidation and heat loss caused by material transfer, and fully utilizes the advantages of microwave heating and selective activation, as well as the forced convection and efficient condensation advantages of electromagnetic stirring. This improves the purification effect. Microwave heating has high energy utilization rate, electromagnetic stirring has no contact pollution, the whole system is closed and environmentally friendly, maintains efficient preparation work, and is green and environmentally friendly.

[0032] Specifically, a traveling wave electromagnetic coil 401 is installed outside the molten aluminum. An alternating electromagnetic field is applied, inducing a current in the melt. This induced current interacts with the magnetic field to generate a Lorentz force, driving the melt to move. Compared to mechanical stirring, the strong flow generated by the traveling wave electromagnetic coil 401 continuously disperses the boundary layer liquid rich in impurities, mixing it with the main melt. This prevents impurities from accumulating at the interface or even being re-entrained into the solidified crystals, thus greatly improving purification efficiency. By adjusting the current and frequency of the electromagnetic generator 4, the stirring force can be precisely controlled, from gentle mixing... When combined with intense turbulence, electromagnetic stirring is non-contact, which avoids contamination of the molten aluminum and prevents the entrapment of gas. It is particularly suitable for the preparation of high-purity materials. The flow of the melt makes the temperature and composition more uniform, avoiding local overheating or component segregation. Strong stirring helps the reactants mix and the products diffuse, and enables the fine aluminum droplets to collide, aggregate, and settle more effectively, thereby improving the aluminum recovery rate. During the subsequent solidification process, the flow breaks up the dendrites formed during solidification and promotes the formation of equiaxed crystals, thereby refining the grain structure and improving the mechanical properties of the final high-purity aluminum ingot.

[0033] A method for preparing high-purity aluminum using aluminum ash slag includes the following steps: Step 1: Extend the electric cylinder 203 to open the upper sealing cover 2, and put aluminum ash and flux into the shell 1. Then retract the electric cylinder 203 to seal the upper sealing cover 2 and the shell 1. Step 2: Turn on the microwave generator 3. The aluminum ash and flux above the quartz ceramic plate 102 are microwave heated by the multi-source magnetron plate 302 and stirred by the mode stirrer 207 to change the electromagnetic field distribution in the cavity, disperse the standing waves of the microwaves, and heat evenly. Step 3: Nitrogen and argon are introduced through the ventilation valve 301 and the air inlet pipe 303 as a protective atmosphere to prevent the aluminum liquid from oxidizing. Under the inert and reactive gas conditions, the aluminum ash slag is efficiently denitrified, salts are evaporated, and metal oxides are reduced to convert it into activated aluminum material. The activated aluminum material is melted under the protective atmosphere to form the initial aluminum liquid. The waste gas is discharged through the filter smoke pipe 202 and the exhaust fan 201. Step 4: Drive the rotating shaft 605 to rotate via the stepper motor 6, open the water-cooled butterfly valve 604, and slowly guide the molten aluminum into the water-cooled copper crucible 7. The upper layer of pure molten aluminum, due to its higher density, is located in the lower layer and flows into the lower directional solidification crucible under the action of gravity. The slag is blocked in the upper chamber and will be cleaned later. After the lower water-cooled copper crucible 7 receives the predetermined amount of molten aluminum, after the molten aluminum is discharged, close the water-cooled butterfly valve 604, clean the slag floating on the surface of the upper end of the molten aluminum, start the auxiliary heater, and maintain the temperature of the molten aluminum at slightly above the melting point. Step 5: Start the electromagnetic generator 4, set the initial stirring intensity, direction and mode. By controlling the phase and frequency of the three-phase alternating current, the traveling wave electromagnetic coil 401 generates a traveling magnetic field, which drives the aluminum liquid to rotate horizontally, vertically or in combination, forcefully pushing impurities to the solidification front end, and strongly stirring the aluminum liquid to make the composition uniform and initially precipitate and suspend some high melting point impurities. Step 6: The aluminum liquid solidifies layer by layer from the bottom up. At the solidification interface, the electromagnetic stirrer continues to work, constantly sweeping away the precipitated impurities from the solidification interface and enriching them in the remaining liquid phase. Step 7: Retract the hydraulic cylinder 503 to lower the inner crucible 701. During the descent, the surface of the inner crucible 701 is cooled by the cooling cover 501, establishing a temperature gradient from bottom to top in the melt. The solidified high-purity aluminum ingot is discharged through the feeding hopper 702 and the high-purity aluminum feeding port 504. The final product is a segmented aluminum ingot. The bottom and middle parts are extremely high-purity aluminum, while the top part is aluminum material that has been cut off and is rich in impurities. It can be returned to the device for reprocessing.

[0034] Specifically, based on the initial composition of the molten aluminum, the frequency, current, and mode of the electromagnetic stirring are optimized through model calculations and experimental verification to achieve the best impurity transfer effect, while avoiding violent churning of the liquid surface and entrainment of the oxide film. The positive pressure of the inert gas within the system is monitored and maintained throughout the process to ensure an oxygen-free environment. The exhaust pressure of the upper chamber needs to be precisely controlled to ensure the smooth discharge of volatile substances without disrupting the atmosphere balance.

[0035] Working principle: During use, the electric cylinder 203 extends to open the upper sealing cover 2, allowing aluminum ash and flux to be added into the housing 1. The electric cylinder 203 then retracts, sealing the upper sealing cover 2 and the housing 1. The microwave generator 3 is then activated. The aluminum ash and flux above the quartz ceramic plate 102 are microwave-heated by the multi-source magnetron plate 302 and stirred by the mode stirrer 207, changing the electromagnetic field distribution within the cavity, dispersing microwave standing waves, and achieving uniform heating. Heating by the microwave generator 3 relies on the aluminum ash absorbing microwave energy and converting it into heat energy. The oxides and nitrides in the aluminum ash absorbing energy will violently vibrate and generate heat through friction in the high-frequency electromagnetic field of the microwave, achieving simultaneous heating of the entire material. This avoids the problems of low thermal efficiency and slow heating of traditional external heating methods. For aluminum ash... Materials with low thermal conductivity show particularly significant improvements in heating efficiency. The heating effect of microwaves on different substances depends on their dielectric properties. Non-metallic components such as alumina and aluminum nitride in aluminum slag generally absorb microwaves more readily, while metallic aluminum has relatively weak microwave absorption. Selective microwave heating allows impurities such as aluminum nitride to quickly reach the reaction temperature. When air is introduced, efficient and harmless disposal can be achieved, resulting in the production of high-purity aluminum in a green and environmentally friendly manner. Nitrogen and argon are introduced through the ventilation valve 301 and the air inlet pipe 303 as a protective atmosphere to prevent oxidation of the aluminum liquid. Under the inert and reactive gas conditions, the aluminum slag undergoes efficient denitrification, salt evaporation, and reduction of metal oxides, transforming it into activated aluminum material. The activated aluminum material is then melted under a protective atmosphere to form initial aluminum liquid, which is then filtered... The exhaust pipe 202 and the exhaust fan 201 discharge the exhaust gas. The stepper motor 6 drives the rotating shaft 605 to rotate, opening the water-cooled butterfly valve 604 and slowly guiding the molten aluminum into the water-cooled copper crucible 7. The upper layer of pure molten aluminum, due to its higher density, is located at the bottom and flows into the lower directional solidification crucible under the action of gravity. The slag is blocked in the upper chamber and will be cleaned later. After the lower water-cooled copper crucible 7 receives the predetermined amount of molten aluminum, the water-cooled butterfly valve 604 is closed after the molten aluminum is discharged. The slag floating on the surface of the molten aluminum is cleaned, the auxiliary heater is started, and the temperature of the molten aluminum is maintained slightly above the melting point. The electromagnetic generator 4 is started, and the initial stirring intensity, direction, and mode are set. By controlling the phase and frequency of the three-phase alternating current, the traveling wave electromagnetic coil 401 generates a traveling magnetic field. The electromagnetic stirring mechanism drives the molten aluminum through horizontal rotation, vertical movement, or a combination of both, forcefully pushing impurities towards the solidification front. This intense stirring ensures homogeneous composition and initially precipitates and suspends some high-melting-point impurities. By adjusting the current and frequency of the electromagnetic generator, the stirring force can be precisely controlled, ranging from gentle mixing to vigorous turbulence. The non-contact nature of the electromagnetic stirring prevents contamination of the molten aluminum and avoids gas entrapment, making it particularly suitable for the preparation of high-purity materials. The melt flow promotes more uniform temperature and composition, preventing localized overheating or component segregation. The powerful stirring aids in reactant mixing and product diffusion, and allows for more effective collision, aggregation, and sedimentation of fine aluminum droplets, thereby improving aluminum recovery. The molten aluminum solidifies layer by layer from the bottom up, with continuous electromagnetic stirring at the solidification interface.The precipitated impurities are continuously swept away from the solidification interface and enriched in the remaining liquid phase. The hydraulic cylinder 503 contracts, causing the inner crucible 701 to descend. During the descent, the surface of the inner crucible 701 is cooled by the cooling shroud 501, establishing a temperature gradient from bottom to top in the melt. The solidified high-purity aluminum ingot is discharged through the feeding hopper 702 and the high-purity aluminum feeding port 504. The final product is a segmented aluminum ingot; the bottom and middle sections contain extremely high-purity aluminum, while the top section, containing the cut-off impurities, can be returned to the unit for reprocessing.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. An apparatus for preparing high-purity aluminum using aluminum ash slag, comprising a shell (1), characterized in that, A quartz ceramic plate (102) is installed in the middle of the housing (1). Microwave generators (3) are installed on both sides above the quartz ceramic plate (102). Two water-cooled butterfly valves (604) are installed inside the quartz ceramic plate (102). A water-cooled copper crucible (7) is installed below the two water-cooled butterfly valves (604). Electromagnetic generators (4) are installed on both sides of the lower end of the housing (1). An inner crucible (701) is installed inside the water-cooled copper crucible (7). Traveling wave electromagnetic coils (401) are installed on the outside of the inner crucible (701) and the water-cooled copper crucible (7). The electromagnetic generators (4) are electrically connected to the traveling wave electromagnetic coils (401).

2. The apparatus for preparing high-purity aluminum using aluminum ash slag according to claim 1, characterized in that, A support frame (101) is installed on the outside of the housing (1). The support frame (101) is connected to the housing (1) and the microwave generator (3) by fixing screws. The microwave generator (3) extends into the inside of the housing (1) and is sealed to the housing (1).

3. The apparatus for preparing high-purity aluminum using aluminum ash slag according to claim 1, characterized in that, The quartz ceramic plate (102) is fixedly connected to the housing (1), and the edge of the quartz ceramic plate (102) is sealed to the inner wall of the housing (1). Two integrally formed feed inlets (103) are provided on the quartz ceramic plate (102). The feed inlets (103) are sealed to the water-cooled butterfly valve (604). A stepper motor (6) is installed on one side of the housing (1). A magnetic brake (601) and a reducer (602) are installed at one end of the motor shaft of the stepper motor (6). A rotating shaft (605) is connected to one end of the magnetic brake (601) and the reducer (602). The rotating shaft (605) passes through the water-cooled butterfly valve (604) and is fixedly connected to the water-cooled butterfly valve (604) by a locking sleeve. A bearing seat (603) is installed outside the housing (1), and the rotating shaft (605) is rotatably connected to the housing (1) through the bearing seat (603).

4. The apparatus for preparing high-purity aluminum using aluminum ash slag according to claim 2, characterized in that, The bottom of the housing (1) is provided with an inspection port (104), and the upper end of the housing (1) is provided with an upper sealing cover plate (2). A folding plate (204) is welded to one end of the upper sealing cover plate (2). A hydraulic hinge (205) is installed between the folding plate (204) and the housing (1). The upper sealing cover plate (2) is movably connected to one end of the housing (1) through the hydraulic hinge (205).

5. The apparatus for preparing high-purity aluminum using aluminum ash slag according to claim 4, characterized in that, A connecting ear (206) is installed at the other end of the upper sealing cover (2), and an electric cylinder (203) is installed on one side of the upper sealing cover (2). The upper end of the electric cylinder (203) is hinged to the connecting ear (206), and the lower end of the electric cylinder (203) is fixedly connected to the support frame (101).

6. The apparatus for preparing high-purity aluminum from aluminum ash slag according to claim 5, characterized in that, A filter pipe (202) is installed at the upper end of the upper sealing cover (2), and an exhaust fan (201) is installed in the middle of the filter pipe (202). The filter pipe (202) extends into the housing (1) and is fixedly connected to the upper sealing cover (2). The upper sealing cover (2) and the housing (1) are sealed together by a sealing gasket. Two mode stirrers (207) are installed on the upper sealing cover (2). Both mode stirrers (207) are used to extend into the housing (1) to disperse the standing waves of microwaves.

7. The apparatus for preparing high-purity aluminum from aluminum ash slag according to claim 1, characterized in that, The microwave generator (3) is equipped with an external air exchange valve (301) and an internal air inlet pipe (303). The air inlet pipe (303) is used to introduce the gas required for the high-purity aluminum preparation reaction. A multi-source magnetron plate (302) is installed inside the microwave generator (3), and a pulse magnetron is installed inside the multi-source magnetron plate (302).

8. The apparatus for preparing high-purity aluminum from aluminum ash slag according to claim 7, characterized in that, A support base (5) is installed below the shell (1), and two cooling covers (501) are installed on the shell (1). Positioning frames (703) are installed on both sides of the lower end of the inner crucible (701). A hydraulic cylinder (503) is installed between the positioning frame (703) and the support base (5). A hydraulic oil pump (508) is installed below the hydraulic cylinder (503).

9. The apparatus for preparing high-purity aluminum from aluminum ash slag according to claim 8, characterized in that, An electrical box (502) is installed on the upper end of the support base (5), and a cooling water tank (506) is provided inside the support base (5). A circulating water pipe (505) is installed inside the cooling cover (501). The circulating water pipe (505) is connected to the cooling water tank (506) through a water pump. A radiator (507) is installed on the outside of the cooling water tank (506). The inner crucible (701) descends into the cooling cover (501) and is cooled by water cooling through the cooling water in the circulating water pipe (505). A feeding hopper (702) is provided at the lower end of the inner crucible (701). A high-purity aluminum feeding port (504) is provided at the lower end of the support base (5). The position of the high-purity aluminum feeding port (504) corresponds to the position of the feeding hopper (702). A valve is provided at the bottom of the feeding hopper (702).

10. A method for preparing high-purity aluminum from aluminum ash slag, implemented based on the apparatus for preparing high-purity aluminum from aluminum ash slag as described in claim 9, characterized in that, Includes the following steps: Step 1: Extend the electric cylinder (203) to open the upper sealing cover (2), put aluminum ash and flux into the shell (1), retract the electric cylinder (203) to seal the upper sealing cover (2) and the shell (1). Step 2: Turn on the microwave generator (3), and the aluminum ash and flux above the quartz ceramic plate (102) are microwave heated by the multi-source magnetron plate (302) and stirred by the mode stirrer (207) to change the electromagnetic field distribution in the cavity, disperse the standing waves of the microwave, and heat evenly. Step 3: Nitrogen and argon are introduced through the ventilation valve (301) and the air inlet pipe (303) as a protective atmosphere to prevent the aluminum liquid from oxidizing. Under the inert and reactive gas conditions, the aluminum ash slag is efficiently denitrified, salts are evaporated, and metal oxides are reduced to convert it into activated aluminum material. The activated aluminum material is melted under the protective atmosphere to form the initial aluminum liquid. The waste gas is discharged through the filter smoke pipe (202) and the exhaust fan (201). Step 4: Drive the rotating shaft (605) to rotate by stepper motor (6), open water-cooled butterfly valve (604), slowly guide the aluminum liquid into water-cooled copper crucible (7), and after the aluminum liquid is discharged, close water-cooled butterfly valve (604) and clean the slag floating on the surface of the upper end of the aluminum liquid. Step 5: Start the electromagnetic generator (4). By controlling the phase and frequency of the three-phase AC power, the traveling wave electromagnetic coil (401) generates a traveling magnetic field, which drives the aluminum liquid to rotate horizontally, vertically or in combination, and forcefully pushes the impurities to the solidification front. Step 6: The aluminum liquid solidifies layer by layer from the bottom up. At the solidification interface, the electromagnetic stirrer continues to work, constantly sweeping away the precipitated impurities from the solidification interface and enriching them in the remaining liquid phase. Step 7: Retract the hydraulic cylinder (503) to drive the inner crucible (701) down. During the descent, the surface of the inner crucible (701) is cooled by the cooling cover (501). The solidified high-purity aluminum ingot is discharged through the feeding hopper (702) and the high-purity aluminum feeding port (504).

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