Molten metal refining system adopting pneumatic turbine stirring and refining method of molten metal refining system

Abstract

The invention discloses a pneumatic turbine stirring molten metal refining system and a refining method thereof.The pneumatic turbine stirring molten metal refining system comprises a refining nozzle integrated at the tail end of a mechanical arm, the refining nozzle comprises a tubular body which can vertically stretch into a molten pool, and the lower portion of the tubular body is located below the liquid level of the molten pool; a lumen of the tubular body is configured to deliver a refining gas; a turbine component is arranged at the upper part of the tubular main body, the turbine component is arranged in a driving cavity, and a gas inlet port of the driving cavity is communicated with fluid output by a driving gas source and is used for guiding driving gas to the turbine component; a mechanical stirring component is arranged at the lower end of the tubular main body; the turbine component can drive the tubular main body and the mechanical stirring component to synchronously rotate; and the tubular main body and the mechanical stirring component are made of a high-temperature-resistant material. Through deep fusion of pneumatic turbine driving, mechanical stirring, double-gas-path injection and intelligent control, accurate and controllable bubble micronization and powder uniform dispersion can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal solution refining, in particular to a metal melt refining system with pneumatic turbine stirring and a refining method thereof. BACKGROUND

[0002] The refining treatment of metal melt is a key link in the process of casting, metallurgy and metal material preparation. At present, the widely used refining methods in industry are mainly gas refining method and powder spraying refining method, both of which have certain limitations. Therefore, the existing technology has a rotating lance / rotor powder spraying system which combines the two. The system uses a motor to drive a rotor to blow in gas and powder while performing mechanical stirring in order to break up the bubbles and uniformly disperse the powder. However, this system has significant inherent defects, such as the deployment difficulty of the motor in high-temperature harsh environment, the deformation and vibration of the long transmission shaft under high temperature, which affects the sealing performance and transmission efficiency, the lack of real-time monitoring and feedback of the reaction state in the melt pool, the serious dependence on workers' experience in the production process, and the difficulty in ensuring the stability and consistency of product quality, etc.

[0003] Therefore, there is an urgent need in the field for a new type of metal solution refining technology and equipment that can adapt to high-temperature harsh environment, achieve bubble miniaturization and uniform dispersion of powder, and be intelligently and accurately controlled, in order to solve the long-standing technical bottleneck problems. SUMMARY

[0004] The present application provides a metal melt refining system with pneumatic turbine stirring and a refining method thereof, which overcomes the deficiencies in the prior art. Through the deep integration of pneumatic turbine driving, mechanical stirring, double-gas-path blowing and intelligent control, precise and controllable bubble miniaturization and uniform dispersion of powder can be achieved.

[0005] Technical solution: To achieve the above-mentioned purpose, the metal melt refining system with pneumatic turbine stirring and the refining method thereof of the present application, comprising a refining nozzle integrated at the end of a mechanical arm, the refining nozzle comprising a tubular body capable of being vertically inserted into a melt pool with its lower part below the liquid surface of the melt pool; the tubular body is configured to transport refining gas; the upper part of the tubular body is provided with a turbine member, the turbine member is arranged in a driving cavity, the driving cavity is in fluid communication with the output of a driving gas source through an inlet port, for guiding the driving gas to the turbine member to make the turbine member rotate; the lower end of the tubular body is provided with a mechanical stirring member, the rotation of the turbine member can drive the tubular body and the mechanical stirring member to rotate synchronously; the tubular body and the mechanical stirring member are made of high-temperature resistant material.

[0006] Further, the driving gas is compressed air or directly uses the refining gas itself.

[0007] Further, the driving gas is all of the refining gas, and the outlet end of the driving cavity is in fluid communication with the lumen of the tubular body, so that the refining gas after driving the turbine member to rotate can be sprayed into the molten pool.

[0008] Further, the driving gas is part of the refining gas, and the part is pure refining gas, and the remaining part is powder-containing refining gas for conveying and blowing refining agent powder; the powder-containing refining gas is directly sprayed into the molten pool through the lumen of the tubular body; the pure refining gas flows through the driving cavity and then is sprayed into the molten pool through the lumen of the tubular body.

[0009] Further, the high-temperature-resistant material is one or more of graphite, silicon carbide, and silicon nitride.

[0010] Further, it further comprises a first gas path for conveying the refining gas carrying the refining agent powder through the tubular body and finally sprayed into the molten pool; a second gas path for conveying the driving gas through the driving cavity; a control module for adjusting the flow of gas in the first gas path and the second gas path, respectively; the control module comprises a monitoring unit for monitoring and feeding back the size of the bubble size generated by the refining gas in the molten pool in real time, when the bubble size is too small or too large, the control module correspondingly reduces or increases the flow of gas in the second gas path to correspondingly weaken or enhance the bubble breaking effect; when the driving gas is pure refining gas, the control module can adjust the flow of gas in the first gas path and the second gas path, when the flow of gas in the second gas path is reduced or increased, the flow of gas in the first gas path is correspondingly increased or reduced in proportion to maintain the total gas amount stable; the first gas path is provided with a powder distribution module for adjusting the addition amount of refining agent powder according to the flow of gas in the first gas path.

[0011] Further, the monitoring unit is one or more high-temperature-resistant acoustic sensors installed near the refining nozzle and above the molten pool for collecting the acoustic signals generated by the bubble breaking in the molten pool, and indirectly monitoring the distribution of bubble size by analyzing the frequency spectrum characteristics of the acoustic signals.

[0012] Further, it comprises the following steps: S1, extending the refining nozzle into the molten pool by a mechanical arm and an actuator arranged thereon;

[0013] S2, introducing driving gas into the driving cavity, the driving gas flows through and impacts the turbine member, so that it drives the tubular body and the mechanical stirring member to rotate synchronously;

[0014] S3, introducing refining gas into the lumen of the tubular body at the same time;

[0015] S4, blowing the refining gas in the molten pool through the tubular body, and breaking the bubbles of the blown refining gas by the rotating mechanical stirring member to form bubbles of a proper size and uniformly diffuse and distribute;

[0016] or blowing the pure refining gas and the powder-containing refining gas in the molten pool through the tubular body respectively, breaking and mixing the blown pure refining gas and powder-containing refining gas by the rotating mechanical stirring member, and further breaking the bubbles of the mixed refining gas to form bubbles of a proper size and uniformly diffuse and distribute.

[0017] Further, the control module pre-stores a plurality of multi-stage refining process recipes matched with different metal materials and refining targets; the recipe defines target set values or variation curves of the flow rate Q2 of the second gas path, the flow rate Q1 of the first gas path, and the adding amount of the refining agent powder at different time stages of the refining process; the control module automatically executes according to the selected recipe and dynamically fine tunes the set values according to the real-time bubble size information fed back by the monitoring unit.

[0018] Further, the rotation speed R of the turbine member is controlled by adjusting the flow rate Q2 of the gas in the second gas path 3; according to the real-time flow rate Q2 of the second gas path, the pre-stored empirical function K=f(Q2) is inquired to obtain a correction coefficient K, and then the flow rate Q1 of the first gas path is adjusted so that the total gas amount Q 总 = Q1+K* Q2 remains constant or varies according to a preset process curve; the adding amount of the refining agent powder mixed into the first gas path per unit time is adjusted by the powder adding module so that the total input amount of the refining agent powder into the molten pool per unit time remains constant or varies according to a preset process curve.

[0019] Beneficial effects: the pneumatic turbine stirring metal molten liquid refining system and the refining method thereof at least have the following advantages: 1. The three key functions of rotary stirring, inert gas refining, and refining agent powder injection are integrated on a compact nozzle, avoiding the complexity of multi-device operation and improving the processing efficiency.

[0020] 2. The mechanical stirring is driven by the pneumatic turbine structure, avoiding the use of traditional electric motors above the high-temperature molten pool, and solving the problems of motor high-temperature resistance, sealing, and explosion-proof.

[0021] 3. Part of the refining gas is ingeniously used as driving gas, reducing energy consumption.

[0022] 4. The molten pool state is monitored by the control module, and the flow rates of the two gas paths and the adding amount of the powder are controlled in linkage, realizing closed-loop feedback control and significantly improving the consistency of the refining effect and the metal quality.

[0023] 5. The main body of the refining nozzle is made of graphite and coated with boron nitride, which has good high temperature resistance, thermal shock resistance and wetting property to molten metal. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Figure 1 is an assembly diagram of the refining nozzle of the present application;

[0025] Figure 2 Figure 2 is a schematic diagram of the overall structure of an embodiment of the refining nozzle of the present application;

[0026] Figure 3 Figure 3 is a schematic diagram of the upper structure and internal gas flow path of the refining nozzle of the first embodiment of the present application;

[0027] Figure 4 Figure 4 is a schematic diagram of the upper structure and internal gas flow path of the refining nozzle of the second embodiment of the present application;

[0028] Figure 5 Figure 5 is a schematic diagram of the general flow path of the two refining gases of the refining nozzle of the third embodiment of the present application. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with the accompanying drawings.

[0030] As shown in the accompanying drawings Figures 1-5 The present application discloses a kind of pneumatic turbine stirring metal melt refining system and its refining method, including refining nozzle 1, it is integrated in the end effector of mechanical arm 10 by flange or quick connector, mechanical arm 10 can adopt six-axis industrial robot or be equipped with pitch telescopic arm mobile platform, with enough degree of freedom and working range, can accurately, stably immerse refining nozzle 1 in specified position of melt pool, and can move according to preset path, to realize no dead angle refining in melt pool.

[0031] The core of the refining nozzle 1 is that it is an integrated structure, it includes tubular body 11, can be vertically extended into melt pool, and make its lower part below melt pool liquid level;The lumen of the tubular body 11 is configured to transport refining gas, can directly spray refining gas into melt pool, and refining gas can also carry refining agent powder together and spray into melt pool, to improve refining effect;The refining gas is argon or nitrogen.

[0032] The upper portion of the tubular body 11 is provided with turbine member 12, in the embodiment, turbine member 12 is a micro radial turbine, turbine member 12 is sealed and contained in a driving cavity 13 made of heat-resistant stainless steel.

[0033] The driving cavity 13 is provided with an air inlet port, the air inlet port of the driving cavity 13 is in fluid communication with the output of the driving gas source, and is used to guide the driving gas to the turbine member 12; the air inlet port injects the driving gas tangentially from the side wall of the driving cavity, impacts the turbine blade, and makes the turbine blade rotate, and the turbine impeller can be made of a high-temperature-resistant material such as graphite.

[0034] The lower end of the tubular body 11 is provided with a mechanical stirring member 14 in the form of a propeller impeller structure with multiple inclined blades, and the turbine member 12 is fixedly connected with the tubular body 11, so that when the turbine member 12 rotates, it can drive the tubular body 11 and the mechanical stirring member 14 to rotate synchronously, and the synchronous rotation is coaxial, same direction and same speed.

[0035] Since the tubular body is vertically inserted into the molten pool and rotates synchronously with the bottom mechanical stirring member 14, when the refining gas is sprayed from the bottom of the tubular body, it will quickly spread in the form of bubbles to the surrounding annular area and move upward at the same time, so that the bubbles can just pass through the annular stirring area of the mechanical stirring member 14, and the huge shear force generated by stirring can further break the rising bubbles and promote the rising and diffusion of the bubbles, so that the bubbles can be uniformly distributed in the molten pool, and if the refining gas also carries refining agent powder, it can also assist the diffusion of the refining agent in the molten pool, thereby improving the refining effect.

[0036] Since the tubular body 11 and the mechanical stirring member 14 need to be inserted into the molten pool and directly contact with the metal melt, the tubular body 11 and the mechanical stirring member 14 are made of high-temperature-resistant materials. The high-temperature-resistant materials can be graphite, silicon carbide, silicon nitride, etc. Since these materials all have excellent high-temperature resistance, the service life of the refining spray head is effectively prolonged.

[0037] Taking aluminum liquid refining as an example, each of the three materials of graphite, silicon carbide and silicon nitride has its own advantages. Among them, both silicon carbide and silicon nitride are excellent advanced engineering ceramic materials. First of all, both of them have excellent high-temperature strength, and the strength almost does not decay at high temperature of aluminum liquid.

[0038] In addition, silicon carbide has excellent resistance to molten aluminum liquid and almost does not wet, but its thermal shock resistance is general and there is a risk of thermal stress cracking, which can be solved by preheating operation. Silicon nitride has very good resistance to aluminum liquid corrosion and much better thermal shock resistance than silicon carbide, which is closer to graphite, but its cost is also higher than that of silicon carbide.

[0039] Of course, since both are ceramic structure, poor machinability, only sintering, for more complex structure is difficult to manufacture, or the cost of investment required is higher. In this regard, graphite has greater advantages, it has unparalleled thermal shock resistance and machinability, can easily process any complex shape of turbine and flow channel, and completely not afraid of rapid cooling and heating, although the relative solubility of graphite in aluminum liquid is low, but still has the possibility of pollution melt, and graphite is easily infiltrated by aluminum liquid, the present application solves the problem by compounding boron nitride coating on the surface. Since the cost of graphite matrix is lower, even if the coating is added, the total cost is usually lower than that of the overall silicon carbide or silicon nitride parts. It is a material selection scheme that balances performance, machinability and cost, and is more suitable for early product development.

[0040] Therefore, in the refining of aluminum liquid, for the manufacture of refining nozzle structure with complex structure design, graphite is preferably used as the matrix, and at least boron nitride coating is compounded on the surface of the part in contact with the solution. Mainly take advantage of the excellent thermal shock resistance and machinability of graphite matrix, and the surface of the composite coating solves the fatal problem of graphite reaction with aluminum liquid.

[0041] And for mass production requirements, usually the service life of the nozzle is required to be extremely high, and a nozzle with relatively simple structure can be considered, and the cost budget can be appropriately increased to manufacture a batch of silicon carbide nozzles with high performance and long service life, which meets the commercialization demand.

[0042] For some extreme requirements in the field of aerospace, high-end automobile parts manufacturing, etc., silicon nitride can be considered to obtain the peak performance.

[0043] When graphite is used, even if the coating is optimized, there is still a service life limit between the coating and the matrix, so the part of the refining nozzle 1 inserted into the high-temperature metal melt is still a vulnerable part compared to other parts, only the service life is longer than that of other materials. Therefore, the tubular body 11 and the turbine member 12 are detachably fixedly connected, and this part is a standardized and quickly replaceable module, which maintains long-term stable operation of the system through low-cost replacement, greatly reducing maintenance cost and time.

[0044] Then design a convenient replacement structure, as shown in the accompanying Figures 2-5 The upper and lower ends of the hub part of the turbine member 12 are respectively installed with bearing structures with rotary sealing function and the driving cavity 13 to prevent gas leakage from the rotary gap, and then the tubular body 11 is connected by screwing at the lower end of the hub part of the turbine member 12, and is coaxial with the turbine member 12, and the threaded structure facilitates the disassembly and replacement of the tubular body 11.

[0045] In summary, the core of the refining nozzle structure lies in integrating rotary stirring and inert gas refining into a compact nozzle, avoiding the complexity of operating multiple devices and improving processing efficiency. Simultaneously, using gas as a drive source to form a pneumatic turbine structure to rotate the mechanical stirring component 14 avoids the use of traditional electric motors above the high-temperature molten pool, solving the problems of high-temperature resistance, sealing, and explosion-proofing of motors.

[0046] Based on the above nozzle structure, further analysis of the selection scheme of the driving gas reveals two main directions: the driving gas is either compressed air or the refined gas itself.

[0047] In Example 1, compressed air is used as the driving gas. The compressed air is delivered into the driving chamber 13 via a dedicated pipeline. After performing work on the turbine blades through the driving chamber 13, it is directly discharged. The refining gas, on the other hand, is directly delivered through the inner cavity of the tubular main body and injected into the molten pool. The advantage is that the compressed air and refining gas do not interfere with each other and can be adjusted independently. By adjusting the flow rate or pressure of the compressed air, the rotation speed of the mechanical agitator can be controlled, thereby adjusting the bubble-breaking effect and ensuring that the bubbles are always maintained within a suitable size range. Simultaneously, the input amount of refining gas can also be adjusted according to process requirements, maintaining an appropriate addition amount to ensure optimal refining results.

[0048] The specific refining gas delivery route is shown in the attached diagram. Figure 3 As shown, an axial through hole can be opened on the central axis of the hub of the turbine component 12. The upper end of the through hole is connected to the supply source fluid of the refining gas through a rotary sealing joint, while the lower end is directly connected to the cavity of the tubular body 11. The entire conveying path is mostly straight, with low resistance, which can meet the flow of refining gas carrying refining agent powder, and further realize the integration of the bottom spraying function of refining agent into the refining nozzle. The refining gas is sprayed out in the molten pool to form bubbles. The rotating mechanical stirring component 14 can break up and refine the generated bubbles, thereby increasing the gas-liquid reaction area to enhance the refining effect. If the refining gas carries refining agent powder, it can also allow the agent to diffuse evenly in the molten pool, further optimizing the refining effect.

[0049] Considering that compressed air requires an additional power unit (compressor pump) for delivery, resulting in significant energy consumption, it is advisable to use refined gas directly as the driving gas. This can be broadly categorized into two approaches: the driving gas can be entirely refined gas or partially refined gas. Structurally, the fluid at the outlet of the driving chamber 13 is connected to the lumen of the tubular body 11, allowing the refined gas used to drive the turbine component 12 to rotate to be injected into the molten pool for refining, thus avoiding waste of the refined gas. This can be achieved through the following two embodiments.

[0050] Example 2 uses all refined gas as the driving gas. In Example 1, the gas (such as argon or nitrogen) that was directly injected into the molten pool for refining is instead injected into the molten pool after flowing through the driving chamber. This replaces compressed air with refined gas as the driving gas, achieving dual use of the refined gas, greatly reducing energy consumption and saving refining costs.

[0051] Therefore, in the design of the refining gas transportation path, as shown in the appendix... Figure 4 As shown, the pipeline for conveying the refining gas can be directly connected to the inlet port of the drive cavity 13. The hollow design of the turbine blades in Embodiment 1 is retained, but the upper port of the axial through hole that was originally connected to the refining gas is changed to a closed state to form a hollow shaft cavity. Then, the turbine component 12 is designed as a centripetal turbine, with the flow channel between its blades extending from the outer edge to the central hub area, so that the gas can flow from the outer edge to the center. Holes, such as multiple radial holes or annular grooves, are opened in the central hub area so that the gas that converges to the center can enter the hollow shaft cavity through the holes. The lower port of the turbine component 12 is still connected to the cavity of the tubular body 11 to realize its function of spraying into the molten pool.

[0052] The advantage of this embodiment is that it cleverly utilizes the refined gas as the driving gas, which is more energy-efficient. However, since the refined gas directly impacts the turbine component 12, if the refined gas carries refined agent powder, it will cause erosion and wear on the turbine blades. Furthermore, due to the complex flow channel structure, the powder may deposit in the flow channel, affecting the dynamic balance or even causing blockage. Therefore, it is not suitable for further integration of refined powder blowing function, and its application range may be limited.

[0053] In Example 3, in order to combine the beneficial effects of Examples 1 and 2 above, it is considered to split the refining gas, with one part used as driving gas (pure refining gas) and the other part used to transport and spray refining agent powder (powder-containing refining gas).

[0054] In this process, the powder-containing refining gas is directly injected into the molten pool through the cavity of the tubular body 11; the pure refining gas flows through the drive cavity 13 and then is injected into the molten pool through the cavity of the tubular body 11. In this way, the refining gas is still used to drive the turbine components to rotate instead of compressed air, realizing the dual use of the refining gas and achieving the purpose of reducing energy consumption. It also avoids the erosion and wear of the turbine blades by the refining agent powder. On the basis of energy saving, it can further integrate the refining powder blowing function without affecting the life of the nozzle components.

[0055] In terms of specific implementation structure, the design of the conduction relationship between the drive cavity 13, the turbine component 12 and the tubular body 11 in Embodiment 1 and Embodiment 2 can be integrated into one.

[0056] Specifically, the tubular body 11 is internally machined to form a coaxially arranged central cavity and an outer annular cavity. The central cavity is a vertical circular hole, and the outer annular cavity is an annular gap surrounding the central cavity. A central nozzle is formed in the central cavity on the bottom end face of the tubular body 11, and an annular gap nozzle is formed in the outer annular cavity surrounding the central nozzle. Then, circumferential channels and radial channels are formed in the hub portion of the turbine component 12. Refined gas carrying refining agent powder passes through the axial channel when passing through the turbine component 12, and through the outer annular cavity on the outside of the tubular body 11. This outer annular cavity has a larger cross-section and is more suitable for transporting powder-containing gas, and is finally ejected from the annular gap nozzle. On the other hand, pure refined gas passes through the radial channel when passing through the turbine component 12, and through the central cavity on the tubular body 11, and is finally ejected from the central nozzle. Preferably, the axial channel and the radial channel are evenly distributed along the circumference of the hub, and are arranged intersectingly. More specifically, the radial channel can be opened in the hub area between adjacent blades of the turbine component 12, while the axial channel can be opened in the hub area corresponding to the radial direction of each blade of the turbine component 12.

[0057] The two air circuits are independent of each other. If one circuit experiences a slight fluctuation, it will not affect the core function of the other circuit. For example, even if the powder delivery is temporarily stopped, the impeller can still rotate and stir, which can prevent the nozzle from being blocked by solidified aluminum liquid and provide a time window for troubleshooting.

[0058] The biggest advantage is that the pure inert gas enters the drive chamber and drives the turbine blades to rotate, completely avoiding the risk of erosion and wear and scale buildup caused by refining agent powder on the high-speed rotating turbine blades, thus improving the turbine's lifespan and stability. Furthermore, in terms of process, it allows for independent adjustment and control of the two key parameters: mechanical stirring and gas stirring.

[0059] Furthermore, both the refining gas used for final drive and the refining gas used for powder feeding are ejected within the molten pool, making the impeller for mechanical stirring function not only to break up bubbles, but also to become a highly efficient static mixer. The strong shearing force generated by high-speed rotation mixes the two independently ejected gases within the molten pool.

[0060] The metal solution refining control system of Embodiment 1 and Embodiment 3 above both require two gas supply paths to supply gas separately. They can be divided into a first gas path 2, which is used to transport refining gas directly through the tubular body 11 and finally spray it into the molten pool to realize the spray refining operation; and a second gas path 3, which is used to transport the driving gas through the driving cavity 1 to realize the driving mechanical stirring.

[0061] An additional control module is provided to adjust the flow rate of gas in the first gas path 2 and the second gas path 3 respectively. Since the two gas paths are independent of each other, the stirring speed, the amount of refining gas added, and the amount of refining agent powder added can be independently controlled according to refining requirements.

[0062] The control module includes a monitoring unit for monitoring and providing real-time feedback on the size of the bubbles generated by the refining gas in the molten pool. In Example 1, when the bubble size is detected to be too small or too large, the control module can correspondingly reduce or increase the flow rate of compressed air in the second gas path (3) to weaken or enhance the crushing effect, thereby meeting the refining requirements.

[0063] More specifically, in Example 3, since the two streams of refining gas are used as driving and powder spraying respectively, and are ultimately sprayed into the molten pool for use, when the amount of refining gas is adjusted according to process requirements, the total amount of refining gas will fluctuate. Therefore, a control strategy is needed to coordinate the adjustment of the two streams of refining gas to ensure that the total amount of refining gas is stable (the total gas volume remains constant or changes according to the preset process curve).

[0064] A metal solution refining control system using the refining nozzle in Embodiment 3 above, wherein the first gas path 2 is connected to the outer annular cavity and is used to transport refining gas carrying refining agent powder, and finally spray it out from the annular gap nozzle into the molten pool; the first gas path 2 is provided with a powder distribution module 21, which is used to adjust the amount of refining agent powder added according to the gas flow rate in the first gas path 2.

[0065] Preferably, a flow control valve, a flow meter, and a powder distribution module 21 are sequentially installed on the first gas path 2. The powder distribution module 21 can be a venturi tube type or a screw feeder type powder injector, which can uniformly mix refining agent powder, such as a mixture of hexachloroethane, sodium nitrate, etc., into the gas flow according to the real-time gas flow rate of the first gas path 2.

[0066] The second gas passage 3 is connected to the inlet port of the drive chamber 13, and the fluid at the outlet of the drive chamber 13 is connected to the central shaft cavity. The second gas passage 3 is also equipped with a flow control valve and a flow meter, which delivers pure refined gas to drive the turbine and finally spray it out from the central nozzle into the molten pool.

[0067] The first air passage 2 is equipped with a pressure regulating valve at its front end to balance the pressure of the two air passages. By appropriately lowering the pressure of the first air passage, the pressure of the second air passage 3 is increased, thereby allowing the stirring turbine to have sufficient power to rotate, generate sufficient shear force to break the bubbles, and avoid stirring stagnation due to the large resistance of the metal solution.

[0068] The control module, employing a PLC or industrial PC, is connected via communication lines to all valves, metering devices, and the powder dispensing module 21 on the first gas path 2 and the second gas path 3. The control module contains a pre-written control program to receive user process commands and coordinate the operation of each component. This enables the control module to collaboratively regulate the gas flow rates in the first gas path 2 and the second gas path 3.

[0069] Preferably, the monitoring unit is one or more high-temperature resistant acoustic sensors, which are installed on the bracket of the refining nozzle 1 and located above the molten pool, facing the refining area, to collect the sound wave signals generated by the bursting of bubbles in the molten pool, and to indirectly monitor the distribution of bubble size by analyzing the frequency spectrum characteristics of the sound wave signals.

[0070] Acoustic sensors can collect composite acoustic wave signals generated by the bursting of countless bubbles in a molten pool and transmit them to the signal processing unit of the control module. The signal processing unit then performs spectral analysis, such as Fast Fourier Transform, on the collected acoustic signals, converting the time-domain signal into a frequency-domain signal to obtain a spectrum. If low-frequency components dominate in the spectrum, it indicates that large bubbles are bursting more frequently; conversely, if high-frequency components are significant and abundant, it indicates that small bubbles are bursting more frequently, thus enabling indirect monitoring of bubble size.

[0071] When the refining gas rises in the form of large bubbles, the resulting pumping effect is the main driving force for stirring the molten pool. If the impeller breaks the bubbles into excessively small sizes, although the gas-liquid reaction area increases, the rising speed of the bubbles will be greatly reduced, which may lead to gas stagnation. Therefore, when the bubble size is detected to be too small, the flow rate of the gas in the second gas path 3 can be reduced by the control module to reduce the rotational speed of the turbine and stirring components, thereby reducing the shear force and weakening the crushing effect. Since the reduction of the driving gas reduces the total input of refining gas, the flow rate of the gas in the first gas path 2 needs to be increased proportionally at the same time to maintain the stability of the total gas volume.

[0072] The refining method of the metal solution refining control system corresponding to the above embodiment 3 includes the following steps: S1, preparation and positioning: by the action of the robotic arm 10 and the actuator configured on it, the refining nozzle 1 is vertically immersed into the molten metal pool, so that the mechanical stirring mechanism 14 at its lower part is submerged to a certain depth below the liquid surface.

[0073] S2, Start rotation: Drive gas is introduced into the drive chamber 13 through the second gas passage 3. The drive gas flows through and impacts the turbine component 12, causing it to drive the tubular body 11 and the mechanical stirring component 14 to rotate synchronously.

[0074] Specifically, the control module instructs the valve of the second gas path 3 to open, allowing pure argon gas to enter the drive chamber 13 at a certain pressure (e.g., 0.5 MPa) and flow rate (e.g., Q2 = 15 L / min), impacting the blades of the turbine component 12 and causing it to rotate at high speed (typically 60-250 r / min). The turbine drives the tubular body 11 and the stirring component 14 to rotate synchronously. The driven argon gas enters the central shaft chamber through the outlet of the drive chamber 13 and is finally injected into the molten pool from the central nozzle.

[0075] S3-S4, Powder Refining: Refining gas carrying refining agent powder is introduced into the outer annular cavity through the first gas passage 2; the driving gas is sprayed into the molten pool through the central nozzle, and the refining gas carrying refining agent powder is sprayed into the molten pool through the annular gap nozzle; the driving gas and the refining gas carrying refining agent powder sprayed into the molten pool are dispersed and mixed by the rotating mechanical stirring component 14.

[0076] Specifically, upon initiating rotation, the control module instructs the first gas path 2 to operate. Argon gas, carrying refining agent powder added proportionally by the powder mixing module 21, enters the outer annular cavity and is finally ejected from the annular gap nozzle. At this moment, the gas ejected from the central nozzle and the annular gap nozzle is immediately sheared and dispersed by the high-speed rotating stirring component 14, forming an extremely fine and uniform bubble cluster, which is thoroughly mixed with the refining agent powder. This microbubble greatly increases the gas-liquid reaction area, significantly improving the efficiency of hydrogen and impurity removal; at the same time, the vigorous stirring ensures that the refining agent powder is evenly distributed within the molten pool, avoiding dead zones and enhancing the reaction rate and effect.

[0077] The rotational speed R of the turbine component 12 is controlled by adjusting the gas flow rate Q2 in the second gas path 3; based on the real-time flow rate Q2 of the second gas path 3, a pre-stored empirical function K=f(Q2) is consulted to obtain the correction coefficient K, and then the flow rate Q1 of the first gas path 2 is adjusted to make the total gas volume Q 总 = Q1 + K * Q2 remains constant or varies according to the preset process curve.

[0078] The amount of refining agent powder added to the first gas path 2 by the powder mixing module 21 per unit time is adjusted so that the total input amount of refining agent powder into the molten pool per unit time remains constant or varies according to the preset process curve.

[0079] The core algorithm of the control module ensures process stability. For example, the preset total gas volume Q 总 The speed is 30 L / min. When it is necessary to increase the speed to enhance the crushing effect, Q2 is adjusted from 15 to 20 L / min. At this time, the control module will automatically adjust the flow rate Q1 of the first air passage 2 according to the pre-stored leakage correction coefficient K. For example, through experimental calibration, when Q2=20, K=0.93, Q1=Q 总 - K*Q2 = 30 - 0.93*20 ≈ 11.4 L / min, thus maintaining a basically constant total gas volume. The powder feeding module 21 will also automatically adjust the powder feeding rate according to the new Q1 value to maintain a stable powder concentration.

[0080] The control module has pre-stored multi-stage refining process formulas that match different metal materials and refining targets. The formulas define the target set values ​​or variation curves of the flow rate Q2 of the second gas path 3, the flow rate Q1 of the first gas path 2, and the amount of refining agent powder added at different time stages of the refining process. The control module automatically executes the formulas and dynamically fine-tunes the set values ​​based on the real-time bubble size information fed back by the monitoring unit.

[0081] Taking a certain type of aluminum alloy as an example:

[0082] Start-up phase: Duration 0-2 minutes; objective is stable dispersion, parameters: Q2=10 L / min, Q1=15 L / min, low rotational speed. This ensures a smooth system start-up, followed by a gradual increase in Q2 over several tens of seconds, transitioning to the parameters of the intensive refining phase.

[0083] The reason is that if the bubbles are too small, the flow rate is too high, and the rotation speed is too high at the beginning, the liquid surface will be violently churned, increasing the risk of metal oxidation and gas entrainment. It may also result in poor dispersion of the refining agent, which will float directly to the surface and become scum.

[0084] Intensive refining stage: Duration 2-10 minutes; the goal is a highly efficient reaction, with parameters: Q2=25 L / min, Q1≈5 L / min (when K=0.95), and the highest rotation speed to generate microbubbles, which are relatively smaller in size, but should not be too small.

[0085] On the one hand, refining efficiency is directly proportional to the total surface area of ​​the bubbles. Dividing the same volume of gas into more small bubbles results in an exponential increase in their total surface area. Furthermore, these smaller bubbles rise more slowly and remain in the molten pool longer, allowing more time to capture inclusions. The high-speed mechanical stirring of these tiny bubbles ensures they are evenly dispersed throughout the molten pool, eliminating any dead zones. Of course, these effects are relative; smaller bubbles are not always better. There should be an optimal size range, which can be determined through experimentation or experience.

[0086] Exhaust gas purification stage: duration 10-12 minutes; the goal is to reduce the total gas content in the melt and smoothly push the inclusions adsorbed on the surface by the bubbles to the liquid surface, forming scum that is easy to remove later. The parameters are: Q2=5 L / min, Q1=20 L / min, low rotation speed to generate larger bubbles.

[0087] The reasons are as follows: First, excessively small bubbles rise too slowly, and towards the end of the process, they are needed to effectively and quickly bring captured impurities to the surface. Second, this stage requires reducing the overall gas content in the melt; excessive microbubbles, if unable to rise quickly enough, risk being trapped in the solidified ingot and forming pores, while larger bubbles can escape more completely. Finally, this helps save gas and reduce energy consumption.

[0088] The control module executes automatically based on the selected formula. Simultaneously, acoustic sensors monitor the bubble spectrum in real time. If, during the high-intensity refining stage, the system detects a low dominant sound frequency (indicating excessively large bubble size), the control module dynamically fine-tunes, slightly increasing the flow rate of Q2, such as from 25 L / min to 26 L / min, thereby increasing the rotational speed and enhancing shear force. Conversely, if the detected bubble size is too small, the flow rate of Q2 is slightly decreased to reduce the rotational speed and weaken the shear force, bringing the bubble size back to the optimal small state. This closed-loop control ensures that the refining process is always in an optimal state, maximizing the stability and reliability of the refining effect.

[0089] In summary, this invention provides a highly efficient, precise, automated metal molten metal refining system and method suitable for high-temperature and harsh environments through the deep integration of pneumatic turbine drive, mechanical stirring, dual-air-path injection, and intelligent control.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the above principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A pneumatic turbine-stirred molten metal refining system, comprising a refining nozzle (1) integrated at the end of a robotic arm (10), characterized in that: The refining nozzle (1) includes a tubular body (11) that can extend vertically into the molten pool and has its lower part below the surface of the molten pool; the cavity of the tubular body (11) is configured to transport refining gas; The upper part of the tubular body (11) is provided with a turbine component (12), which is disposed in a drive chamber (13). The air inlet of the drive chamber (13) is connected to the fluid output of the drive gas source, which is used to guide the drive gas to the turbine component (12) so that the turbine component (12) rotates. The lower end of the tubular body (11) is provided with a mechanical stirring component (14), and the rotation of the turbine component (12) can drive the tubular body (11) and the mechanical stirring component (14) to rotate synchronously. The tubular body (11) and the mechanical stirring component (14) are made of high-temperature resistant materials.

2. The metal molten refining system with pneumatic turbine stirring according to claim 1, characterized in that: The driving gas is compressed air or refined gas itself.

3. The metal molten refining system with pneumatic turbine stirring according to claim 2, characterized in that: The driving gas is all of the refined gas, and the fluid at the outlet of the driving chamber (13) is connected to the cavity of the tubular body (11), so that the refined gas after the driving turbine component (12) rotates can be injected into the molten pool.

4. The metal molten refining system with pneumatic turbine stirring according to claim 2, characterized in that: The driving gas is a portion of the refining gas, and this portion is pure refining gas, while the remaining portion is powder-containing refining gas, used to transport and spray refining agent powder; the powder-containing refining gas is directly injected into the molten pool through the cavity of the tubular body (11); the pure refining gas flows through the driving cavity (13) and then is injected into the molten pool through the cavity of the tubular body (11).

5. The metal molten refining system with pneumatic turbine stirring according to claim 1, characterized in that: The high-temperature resistant material is one or more of graphite, silicon carbide, and silicon nitride.

6. The metal molten refining system with pneumatic turbine stirring according to claim 4, characterized in that: It also includes a first gas passage (2) for conveying refining gas carrying refining agent powder through the tubular body (11) and finally ejecting it into the molten pool; The second gas passage (3) is used to deliver the driving gas through the driving cavity (13). The control module is used to adjust the flow rate of gas in the first gas path (2) and the second gas path (3) respectively; The control module includes a monitoring unit for monitoring and providing real-time feedback on the size of the bubbles generated by the refining gas in the molten pool. When the bubble size is detected to be too small or too large, the control module reduces or increases the flow rate of the gas in the second gas path (3) accordingly to weaken or enhance the bubble breaking effect. When the driving gas is a pure refined gas, the control module can coordinately adjust the flow rate of the gas in the first gas path (2) and the second gas path (3). When the flow rate of the gas in the second gas path (3) decreases or increases, the flow rate of the gas in the first gas path (2) is increased or decreased proportionally to maintain the stability of the total gas volume. The first gas path (2) is equipped with a powder dispensing module (21) for adjusting the amount of refined pharmaceutical powder added according to the gas flow rate in the first gas path (2).

7. A pneumatic turbine-stirred molten metal refining system according to claim 6, characterized in that: The monitoring unit is one or more high-temperature resistant acoustic sensors installed near the refining nozzle (1) and above the molten pool. It is used to collect the acoustic wave signals generated by the bursting of bubbles in the molten pool and to indirectly monitor the distribution of bubble size by analyzing the frequency spectrum characteristics of the acoustic wave signals.

8. A refining method for a pneumatic turbine-stirred molten metal refining system according to any one of claims 1-7, characterized in that, Includes the following steps: S1. The refining nozzle (1) is inserted into the molten pool by means of the robotic arm (10) and the actuator configured thereon; S2. Drive gas is introduced into the drive chamber (13). The drive gas flows through and impacts the turbine component (12), causing it to drive the tubular body (11) and the mechanical stirring component (14) to rotate synchronously. S3. Simultaneously, refining gas is introduced into the inner cavity of the tubular body (11); S4. Refining gas is sprayed into the molten pool through the tubular body (11), and the bubbles formed by the sprayed refining gas are broken by the rotating mechanical stirring component (14) to form bubbles of appropriate size and evenly diffuse and distribute them. Alternatively, the pure refined gas and the powder-containing refined gas can be sprayed into the molten pool through the tubular body (11), and the sprayed pure refined gas and the powder-containing refined gas can be dispersed and mixed by the rotating mechanical stirring component (14), and the bubbles formed by the mixed refined gas can be broken to form bubbles of appropriate size and evenly diffused.

9. The refining method of a pneumatic turbine-stirred molten metal refining system according to claim 8, characterized in that: The control module has a multi-stage refining process formula that matches different metal materials and refining targets. The formula defines the target set value or change curve of the flow rate Q2 of the second gas path (3), the flow rate Q1 of the first gas path (2), and the amount of refining agent powder added in different time stages of the refining process. The control module executes automatically according to the selected formula and dynamically fine-tunes the set value based on the real-time bubble size information fed back by the monitoring unit.

10. The refining method of a pneumatic turbine-stirred molten metal refining system according to claim 9, characterized in that: The rotational speed R of the turbine component (12) is controlled by adjusting the gas flow rate Q2 in the second gas path (3); based on the real-time flow rate Q2 of the second gas path (3), the pre-stored empirical function K=f(Q2) is queried to obtain the correction coefficient K, and then the flow rate Q1 of the first gas path (2) is adjusted so that the total gas volume Q 总 = Q1 + K * Q2 remains constant or varies according to the preset process curve; Adjust the amount of refining agent powder added to the first gas path (2) by the powder mixing module (21) per unit time, so that the total input amount of refining agent powder into the molten pool per unit time remains constant or changes according to the preset process curve.

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