Vertical cold crucible induction zone melting purification equipment

Abstract

The invention provides vertical cold crucible induction zone-melting purification equipment, and relates to equipment and a technology for realizing zone-melting purification by adopting a vertical cold crucible induction heating mode. By adopting the cold crucible, a channel for introducing impurities into a melting zone by a crucible material is eliminated, so that the possibility of obtaining high purity is provided, and conditions are provided for realizing the purification of a large-section material; aiming at the defect that the width of a melting zone is not uniform due to the cooling effect of a crucible wall on a melting pool in a cold crucible zone melting technology, the problem is solved by adopting a cold crucible rotating technology and an electromagnetic field offset technology, so that the melting zone obtains uniform width, and a good purification effect is realized. By arranging the crucible rotating device, the material in the crucible rotates in an electromagnetic field, and the temperature uniformity of the section of the material is improved. And an XY-axis displacement table is arranged for the linear module, so that the condition of non-uniform heating of the material on the cross section is corrected, and the uniformity of a melting zone is further improved.

Description

Technical Field

[0001] This invention belongs to the field of metal and alloy purification technology, specifically a vertical cold crucible induction zone melting purification device. Background Technology

[0002] Zone melting purification technology is a physical purification method for materials. Its principle is that materials containing impurity elements exist in a two-phase region during the heating process. Within this temperature region, the concentrations of impurity elements (Cs and Cl) differ between the solid and liquid phases, i.e., a partition coefficient K exists, K = Cs / Cl, and in most cases, Cs > Cl, meaning K < 1. Therefore, when the material solidifies, impurity elements with K < 1 will accumulate in the liquid phase, thus increasing the purity of the solidified material. Figure 1 As shown, if a narrow melting zone 03 is formed in the material 02 in the water-cooled crucible 01, and the melting zone 03 is moved in one direction, the impurities in the material can migrate in the direction of the moving melting zone 03, thus purifying the solidified material. This is the zone melting purification technology. By repeatedly moving the melting zone in one direction, the purity of the material can be greatly improved.

[0003] One of the technical challenges of zone melting purification technology for metals lies in the influence of crucible materials. The bar or rod-shaped metal to be purified typically needs to be placed in a crucible during the zone melting process. Because the molten zone is at a high temperature, the crucible material can react with the material being purified or dissolve and introduce impurities, negatively impacting the purification process and limiting the purification efficiency of zone melting. Some metals can be purified using crucibles made of materials that do not react with them; for example, Cu and Al can use high-purity graphite crucibles, and Si can use quartz crucibles. However, many metals react with various materials, such as rare earth metals, titanium group metals, and refractory metals. They react strongly with carbon, oxides, and nitrides, making it difficult to find crucible materials suitable for zone melting purification.

[0004] For metals for which no suitable crucible material can be found for zone melting purification, floating zone melting can be used. Floating zone melting does not use a crucible; instead, the rod-shaped metal to be purified is placed vertically, and the resulting molten zone relies on surface tension to maintain its position within the metal rod. However, this technique is only suitable for materials with very small diameters. When the diameter of the metal rod is large, the pressure exerted by the material's gravity on the surface of the floating zone will exceed the surface tension, causing the liquid phase molten zone to collapse.

[0005] Using a water-cooled copper crucible can overcome the difficulties caused by crucible material in zone melting purification: First, it avoids the contamination of the purified material by the crucible material due to reaction and corrosion, thus continuously improving the purity of the material; second, the crucible can have a larger diameter, allowing for the purification of larger materials and achieving higher production efficiency. When using an electromagnetic field as the heat source for the melting zone, the crucible must be slit along its length to provide a channel for the electromagnetic field to penetrate the crucible wall.

[0006] Cold crucible induction zone melting and purification technology is divided into two structural types: horizontal cold crucible induction zone melting and purification and vertical cold crucible induction zone melting and purification. (Reference) Figure 2 Vertical cold crucible induction melting purification uses a vertically arranged tubular cold crucible 01, which has the advantage of producing products with regular cross-sections. Horizontal zone melting uses a horizontally placed boat-shaped cold crucible with an open top, so the cross-section of the melting zone is irregular. More importantly, vertical zone melting avoids the phenomenon of severely uneven width of the melting zone under the conditions of horizontal zone melting. That is, in horizontal zone melting, the upper part of the material in the boat-shaped crucible does not have the cooling effect of the crucible wall, so the melting zone is very wide. However, the material at the bottom is in contact with the crucible wall under the action of gravity, and the cooling effect of the crucible wall makes the lower part of the melting zone very narrow, or even unable to form a melting zone at the bottom of the material.

[0007] A disadvantage of vertical zone melting is that the temperature and width of the melting zone are difficult to observe and measure directly due to the obstruction of the crucible walls. (Refer to...) Figure 2 The vertical cold crucible induction melting purification technology also suffers from uneven melting zone. Specifically, the crucible 01 itself and the material 02 inside the crucible always have a slight deviation from the absolute vertical orientation, causing one side of the material to be particularly close to the crucible wall. Under the cooling effect of the crucible wall, the melting zone 03 on that side narrows sharply, resulting in a phenomenon where the melting zone is wider on one side and narrower on the other. The deviation of the induction coil 04 from the center of the material in the crucible will cause the material temperature on one side to be higher. The material in the high-temperature zone melts first, adsorbs onto the crucible wall, and is cooled. Once one side of the melting zone comes into contact with and adsorbs onto the crucible wall, under the action of surface tension, the melting zone on that side will remain attached to the crucible wall and is difficult to detach.

[0008] Therefore, there is an urgent need for a vertical cold crucible induction zone melting and purification device that can solve the problem of uneven melting zone. Summary of the Invention

[0009] To address the aforementioned problems, this invention presents a device and technology for zone melting purification using a vertical cold crucible induction heating method. By employing a cold crucible, the pathway for impurities to be introduced into the molten zone from the crucible material is eliminated, making it possible to obtain high purity and providing conditions for purifying large-section materials. Addressing the drawback of uneven molten zone width caused by the cooling effect of the crucible wall on the molten pool in cold crucible zone melting technology, this embodiment solves this problem by employing cold crucible rotation technology and electromagnetic field deflection technology, resulting in a uniform molten zone width and thus achieving excellent purification effects.

[0010] This invention proposes a vertical cold crucible induction zone melting and purification device, characterized in that it includes a furnace body, a cold crucible system, a power supply system, a linear drive system, and a rotation drive system; The furnace body includes a quartz furnace tube, a furnace tube seat, and an equipment frame; the upper end of the quartz furnace tube is sealed, and the lower end is installed on the upper end of the furnace tube seat through a vacuum seal; the lower end face of the furnace tube seat is connected to a rotary drive system; the furnace tube seat and the linear drive system are installed on the platform of the equipment frame. The cold crucible system includes a water-cooled crucible, which is vertically installed inside a quartz furnace tube and is composed of several slender lobes. The power system includes a power cabinet, flexible cables, an induction coil, and an induction coil support; the induction coil is installed around the outside of the quartz furnace tube, and is fixedly connected to the induction coil support. The power cabinet is connected to the induction coil via flexible cables. The linear drive system includes a linear drive motor, a reducer, a linear module, and a linear drive head. The rotation of the drive motor is reduced by the reducer, and the rotation is converted into linear motion of the linear drive head by the linear module. The induction coil bracket connected to the linear drive head then drives the induction coil to move up and down along the axis of the water-cooled crucible. The rotation drive system is installed below the furnace tube base and includes a rotation drive motor, a reducer, a transmission device, and a rotation drive head. The rotation of the drive motor is reduced by the reducer and then transmitted to the rotation drive head through the transmission device. The rotation drive head drives the water-cooled crucible to rotate around the axis.

[0011] Furthermore, it also includes a vacuum system, which is connected to the side of the furnace tube base.

[0012] Furthermore, it also includes a cooling system; the cold crucible system also includes a water jacket, a main water pipe, and water interfaces. In particular, each of the crucible's lobes is provided with a cooling water channel extending along the height of the crucible; The water jacket is installed in a sealed manner at the lower end of the water-cooled crucible, and the cooling water passage in the water-cooled crucible is connected to the water jacket in a sealed manner. A main water pipe is installed below the water jacket. The main water pipe passes through the bottom surface of the furnace tube seat through a vacuum dynamic seal and extends to the bottom of the furnace tube seat. The main water pipe consists of concentric inner and outer pipes. In the lower section of the main water pipe, the inner and outer pipes are connected to a water interface through a dynamic sealing structure. The water interface is connected to the main water supply and return pipes of the cooling system.

[0013] Furthermore, the linear module includes a lead screw, nut, drive head, linear bearing, and slide rail; The slide rail is equipped with a limit switch that limits the travel range of the induction coil, and the installation direction of the slide rail is parallel to the axis of the water-cooled crucible. The linear module is mounted on a module base, and the module base uses an XY axis displacement stage.

[0014] Furthermore, the rotating drive head is installed at the lower end of the water main pipe of the water-cooled crucible. When the rotating drive head rotates, it drives the water-cooled crucible to rotate around the axis through the water main pipe.

[0015] Furthermore, the dynamic sealing structure includes a sealing sleeve, a sealing ring, a nut, and a compression nut; Two sealing sleeves are respectively wrapped around the inner and outer pipes of the main water pipe to form an annular cavity. The annular cavity is connected to a water hole on the inner or outer pipe. The water interface is installed on the pipe wall of the sealing sleeve and is connected to the annular cavity. The sealing sleeve can rotate relative to the inner and outer pipes of the main water pipe, and a sealing ring is installed in the gap between the sealing sleeve and the inner and outer pipes. The nut tightens the sealing ring, and the tightening nut is used to lock the sealing nut.

[0016] Furthermore, the vacuum system includes a vacuum pump, vacuum valves, and vacuum piping, with the vacuum piping connected to the interface flange of the furnace tube seat.

[0017] Furthermore, the device is also equipped with a camera mounted on the induction coil support to follow the movement of the molten zone and track and measure the width of the molten zone.

[0018] Furthermore, during the zone melting process, the width of the melting zone is 5mm to 100mm; And / or, the induction coil has 1 turn, 2 turns, or several turns. And / or, the moving speed of the molten zone is 0.01 mm / min to 10 mm / min; And / or, the rotation speed of the drive head is 1 rpm to 120 rpm.

[0019] Furthermore, the cross-section of the water-cooled crucible can be circular, square, rectangular, polygonal, or other shapes; And / or, the inner diameter of the water-cooled crucible is 10–500 mm; And / or, the water-cooled crucible has 6 to 60 petals.

[0020] Compared with the prior art, the advantages of the present invention are as follows: 1. This invention designs a cold crucible induction zone melting purification device and a method for metal purification using this device. Because the zone melting process operates in a vacuum or inert gas environment, there is no contamination from gaseous impurities; and because the zone melting uses a water-cooled copper crucible, there is no contamination from the crucible material. Therefore, no impurities enter the material during the zone melting purification process, and increasingly higher purity can be obtained with each additional zone melting cycle.

[0021] 2. Using a cold crucible allows for zone melting purification of materials with large cross-sections, significantly improving the production efficiency of purification technology; 3. Compared with horizontal cold crucible zone melting purification technology, vertical cold crucible zone melting purification technology has the advantage of regular shape of the material product to be purified. More importantly, it reduces the tendency of uneven melting zone width. 4. This invention improves the temperature uniformity of the material cross-section by setting up a crucible rotation device to make the material in the crucible rotate in an electromagnetic field. An XY-axis displacement stage is provided for the linear module to correct uneven heating of the material across the cross-section, which helps to further improve the uniformity of the melting zone.

[0022] 5. This invention proposes a technique for achieving closed-loop control of the molten zone width by using a camera to acquire video images of the molten zone and using image processing technology to obtain data on the molten zone width. 6. This invention provides various types of sensors for the zone melting equipment and uses a PLC module to set up a complete operating program for the zone melting process, enabling the entire zone melting purification process or a part of it to be fully automated. Attached Figure Description

[0023] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0024] Figure 1 Schematic diagram of zone melting purification device; Figure 2 This is a diagram of the non-uniform melting zone that appears in a conventional vertical cold crucible induction melting purification device. Figure 3 This is a schematic diagram of the vertical cold crucible induction zone melting and purification equipment according to this embodiment; Figure 4This is a structural diagram of the vertical cold crucible induction zone melting and purification equipment. Figure 5 This diagram illustrates one possible combination of a linear drive device, an induction coil, and a cold crucible. Figure 6 A diagram of a dynamic sealing structure for the water interface on the main water pipe of a cold crucible; In the diagram, 01-Water-cooled crucible, 02-Material, 03-Melting zone, 04-Induction coil, 05-Furnace body, 06-Cold crucible system, 07-Induction power supply, 08-Linear drive system, 09-Rotary drive system, 10-Vacuum system, 11-Cooling system, 12-Control system, 13-Quartz furnace tube, 14-Furnace tube base, 15-Equipment frame, 16-Water jacket, 17-Main water pipe, 18-Water interface, 19-Petal, 20-Cooling water channel, 21-Inner pipe, 22-Outer pipe, 23-Dynamic sealing structure, 24-Power cabinet, 25-Flexible cable 26-Induction coil bracket, 27-Linear drive motor, 28-Reducer, 29-Linear module, 30-Module base, 31-Linear drive head, 32-Controller, 33-Lead screw, 34-Nut, 35-Linear bearing, 36-Slide rail, 37-Limit switch, 38-Rotary drive motor, 39-Rotary reducer, 40-Transmission device, 41-Rotary drive head, 42-Sealing sleeve, 43-Sealing ring, 44-Sealing nut, 45-Pressure nut, 46-Annular cavity, 47-Water hole, 48-Camera, 49-XY axis displacement stage. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0026] like Figure 2-6 As shown, this embodiment provides a vertical cold crucible induction zone melting purification device. By using a cold crucible, the channel for introducing impurities into the molten zone from the crucible material is eliminated, making it possible to obtain high purity and providing conditions for purifying large cross-section materials. Addressing the drawback of uneven molten zone height caused by the cooling effect of the crucible wall on the molten pool in cold crucible zone melting technology, this embodiment solves this problem by employing cold crucible rotation technology and electromagnetic field deflection technology, resulting in a uniform molten zone height and thus achieving excellent purification effects.

[0027] The vertical cold crucible induction zone melting and purification equipment of this embodiment is described in [reference needed]. Figure 3It includes a furnace body 05, a cold crucible system 06, a power supply system 07, a linear drive system 08, a rotary drive system 09, a vacuum system 10, a cooling system 11, and a control system 12.

[0028] See Figure 4 The furnace body 05 includes a quartz furnace tube 13, a furnace tube seat 14, and an equipment frame 15. The upper end of the quartz furnace tube 13 is sealed, and the lower end is vacuum-sealed and installed on the upper end of the furnace tube seat 14. A vacuum system 10 is connected to the side of the furnace tube seat 14, and a rotary drive system 09 is connected to the lower end face of the furnace tube seat 14. The equipment frame 15 is a platform for mounting the furnace tube seat 14, and a linear drive system 08 is mounted on the surface of the equipment frame 15. It is understood that the surface of the equipment frame 15 must be parallel to a horizontal plane.

[0029] The cold crucible system 06 is installed inside the quartz furnace tube 13 and the furnace tube base 14, and includes a water-cooled crucible 01, a water jacket 16, a main water pipe 17, and a water interface 18. Specifically, the water-cooled crucible 01 is vertically installed inside the quartz furnace tube 13; the water-cooled crucible 01 is composed of several elongated lobes 19, and each lobe 19 is provided with a cooling water channel 20 extending along the height direction of the crucible. The water jacket 16 is sealed at the lower end of the water-cooled crucible 01, and the cooling water channel 20 in the water-cooled crucible 01 is sealed to the water jacket 16. The main water pipe 17 is installed below the water jacket 16, and the main water pipe 17 passes through the bottom surface of the furnace tube base 14 through a vacuum dynamic seal and extends to the bottom of the furnace tube base 14. The main water pipe 17 includes a concentric inner pipe 21 and an outer pipe 22. In the lower section of the main water pipe 17, the inner pipe 21 and the outer pipe 22 are respectively connected to a water interface 18 through a dynamic sealing structure 23. The water interface 18 is connected to the main water supply pipe and the main water return pipe of the cooling system 11.

[0030] It should be noted that the axis of the water-cooled crucible 01 must be strictly perpendicular to the horizontal plane; the centerline of the water manifold 17 must be strictly coaxial with the axis of the water-cooled crucible 01, and the water manifold 17 must be able to move up and down and rotate around the axis while maintaining a seal. Preferably, the cross-section of the water-cooled crucible 01 designed in this embodiment can be circular, square, rectangular, polygonal, or other shapes, and its inner diameter can be selected in the range of 10 to 500 mm. The number of lobes 19 of the water-cooled crucible 01 increases with the increase of the inner diameter of the crucible, and is selected in the range of 6 to 60 lobes.

[0031] The power supply system 07 includes a power cabinet 24, a flexible cable 25, an induction coil 04, and an induction coil support 26. The induction coil 04 is formed by a water-permeable copper pipe and is installed around the outside of the quartz furnace tube 13. The induction coil 04 is fixedly connected to the induction coil support 26, and its circular surface is perpendicular to the centerline of the water-cooled crucible 01. There should be a certain gap between its inner circle and the quartz furnace tube 13. When the power cabinet 24 is started, the electromagnetic field generated by the induction coil 04 creates a melting zone 03 in the material 02 inside the water-cooled crucible 01. As the induction coil 04 moves relative to the material 02 along the height direction of the quartz furnace tube 13, the melting zone 03 moves with the induction coil 04.

[0032] The linear drive system 08 is mounted on the equipment stand 15 and includes a linear drive motor 27, a reducer 28, a linear module 29, a module base 30, a linear drive head 31, and a controller 32. Specifically, the drive motor 27 can be of different types, such as a stepper motor, a servo motor, or an AC motor, and different types of controllers 32 are selected according to different motor types; for AC motors, the controller 32 includes a frequency converter. The rotation of the drive motor 27 is reduced by the reducer 28, and the linear module 29 converts the rotation into linear motion of the linear drive head 31. The induction coil bracket 26, which is connected to the linear drive head 31, then drives the induction coil 04 to move up and down along the axis of the water-cooled crucible 01.

[0033] Better Figure 5 A preferred structure of the linear module 29 is shown. The linear module 29 includes a lead screw 33, a nut 34, a drive head 31, a linear bearing 35, and a slide rail 36. A limit switch 37 is installed on the slide rail 36 to limit the travel range of the induction coil 04. The installation direction of the slide rail 36 must be parallel to the axis of the water-cooled crucible 01 to ensure stable, precise, and vibration-free movement. The linear module 29 is mounted on a module base 30, which preferably uses an XY-axis displacement stage 49 with X and Y positioning directions. This stage allows adjustment of the linear module 29's horizontal position, i.e., adjusting the relative position of the induction coil 04 with respect to the water-cooled crucible 01 in the horizontal direction.

[0034] Continue reading Figure 4The rotation drive system 09 is installed below the furnace tube base 14 and includes a rotation drive motor 38, a reducer 39, a transmission device 40, and a rotation drive head 41. Specifically, the drive motor 38 can be of different types, such as a stepper motor, a servo motor, or an AC motor, and different types of controllers are selected according to different motor types; for AC motors, the controller includes a frequency converter. The rotation of the rotation drive motor 38 is reduced in speed by the reducer 39, and then transmitted to the rotation drive head 41 by the transmission device 40. The rotation drive head 41 is installed at the lower end of the water main pipe 17 of the water-cooled crucible 01. When the rotation drive head 41 rotates, it drives the water-cooled crucible 01 to rotate around its axis through the water main pipe 17.

[0035] It should be noted that, in order to meet the requirement that the water main pipe 17 must rotate around its axis during the zone melting process, while the water interface 18 cannot rotate with it, a specially designed dynamic sealing structure 23 is required. Its feature is that when the water main pipe 17 rotates, it can connect with the fixed water interface 18 while maintaining a seal.

[0036] Figure 6 A sealing structure with this function is shown. Specifically, the dynamic sealing structure 23 includes a sealing sleeve 42, a sealing ring 43, a nut 434, and a clamping nut 45. Two sealing sleeves 42 are respectively wrapped around the inner pipe 21 and the outer pipe 22 of the water main 17 to form an annular cavity 46. The annular cavity 46 communicates with a water hole 47 on the inner pipe 21 or the outer pipe 22. The water interface 18 is installed on the pipe wall of the sealing sleeve 42 and communicates with the annular cavity 46. The sealing sleeve 42 can rotate relative to the inner pipe 21 and the outer pipe 22 of the water main 17. The sealing ring 43 is installed in the gap between the sealing sleeve 42 and the inner pipe 21 and the outer pipe 22. The nut 44 clamps the sealing ring 43 to form a seal between the sealing sleeve 42 and the inner pipe 21 and the outer pipe 22. The clamping nut 45 is used to lock the sealing nut 44 to prevent them from loosening when the water main 17 rotates.

[0037] like Figure 3 In this embodiment, the vacuum system 10 includes a vacuum pump, a vacuum valve, and a vacuum pipeline. The vacuum pipeline is connected to the interface flange of the furnace tube seat 14, enabling a high vacuum level to be obtained inside the quartz furnace tube 13. The vacuum system may include an inert gas device. As needed, after the quartz furnace tube 13 has obtained a predetermined vacuum level, it can be filled with an inert gas at an appropriate pressure to form a protective atmosphere.

[0038] The function of the cooling system 11 is to provide cooling water to the water-cooled crucible 01, induction coil 04, induction power supply 07 and vacuum pump, so as to protect these systems and ensure their safe operation.

[0039] The control system 12 is equipped with a PLC module and a touch screen. Its function is to control the operation of the vacuum system 10, cooling system 11, linear drive system 08, and rotary drive system 09, and to measure their operating status. Measuring instruments include vacuum gauges, pressure gauges, thermocouples, and displacement sensors, which can be used to measure vacuum level, gas pressure, cooling water temperature, and the speed of the molten zone movement. Figure 5 The device is also equipped with a camera 48, which is mounted on the induction coil bracket 26 to follow the movement of the molten zone 03 and measure the width of the molten zone. The induction power supply 07 has its own power control device, and adjusting the power can change the temperature and width of the molten zone 03.

[0040] The control system is equipped with two control modes: manual control and program control. In program control mode, the equipment automatically performs the entire process, or parts thereof, according to the program, from starting the cooling system 11 and vacuum system 10 to starting the induction power supply 07 to heat the material, to forming the melting zone 03, from controlling the temperature, width and moving speed of the melting zone 03, to starting the second melting process after the induction coil 04 returns to its original position after completing one melting process, to stopping the equipment after repeating the melting process several times.

[0041] Controlling the melting zone during zone melting includes factors such as the temperature, width, and moving speed of the melting zone 03. Due to the obstruction of the crucible wall, the temperature of the melting zone 03 cannot be measured under vertical zone melting conditions; however, the width of the melting zone 03 can be observed through the gaps in the crucible flaps 19. In reality, the width of the melting zone 03 depends on the melting zone temperature, so only the width needs to be controlled. For an ideal zone melting process, a very small width of the melting zone 03 is required, for example, 5mm to 100mm. The optimal melting zone width depends on the cross-sectional dimensions of the water-cooled crucible 01; as the cross-sectional dimensions increase, the melting zone width can increase accordingly. The conditions determining the melting zone width include the number of turns of the induction coil 04 and the power output from the induction power supply 07 to the induction coil. To control the melting zone width, the number of turns of the induction coil 04 cannot be too many, usually one, two, or a few turns. With a fixed number of turns in the induction coil 04, the width of the melting zone can be adjusted by regulating the output power of the induction power supply 07. In this embodiment, a camera 48 is used to measure the image of the molten zone. The video signal is sent to the PLC for image processing to obtain the molten zone width data. The PLC compares this data with the pre-input molten zone width command and then adjusts the power supply to achieve closed-loop control of the molten zone width.

[0042] The moving speed of the melting zone 03 in the water-cooled crucible 01 depends on the moving speed of the linear drive head 31 in the linear drive system 08. To achieve an ideal zone melting process, the melting zone must maintain a very low moving speed so that the core of the material can be completely melted, temperature equilibrium can be achieved within the cross-section of the melting zone, and impurities within the melting zone can be sufficiently diffused. The moving speed of the melting zone can be selected within the range of 0.01 mm / min to 10 mm / min. As the cross-sectional size of the material 02 decreases, the moving speed of the melting zone can be slightly increased. To achieve an ideal zone melting process, the moving process of the melting zone must also be stable and vibration-free, requiring the entire equipment and its components to be robust, stable, and vibration-isolated.

[0043] It is worth noting that under vertical zone melting purification conditions, slight deviations in the configuration of the water-cooled crucible 01 and the material 02 within the crucible from their absolute vertical configuration, as well as the offset of the induction coil 04, will lead to uneven width of the molten zone (wider on one side and narrower on the other). To eliminate this adverse phenomenon, the following three measures proposed in this embodiment must be implemented effectively:

[0044] First, precisely install the slide rails 36 of the water-cooled crucible 01 and the linear module 29 so that their axes are parallel and strictly perpendicular to the horizontal plane; precisely install the induction coil 04 so that the cross section of the induction coil 04 is perpendicular to the axis of the water-cooled crucible 01 and the center of the induction coil 04 coincides with the axis of the water-cooled crucible 01. Second, a rotation drive system 09 is installed below the water-cooled crucible 01 to ensure that the material 02 in the water-cooled crucible 01 is uniformly subjected to the electromagnetic field. The rotation speed of the water-cooled crucible 01 depends on the rotation speed of the rotation drive head 41 driven by the rotation driver, and can be selected within the range of 1 rpm to 120 rpm.

[0045] Third, the module base 30 of the linear module 29 is mounted on an XY-axis displacement stage 49, which has two positioning directions, X and Y. The positioning position of the linear module 29 on the horizontal plane can be adjusted by the XY-axis displacement stage 49, thereby adjusting the relative position of the induction coil 04 with respect to the water-cooled crucible 01 in the horizontal direction. When the height of the molten zone 03 is found to be uneven, the XY-axis displacement stage 49 is adjusted to move the center of the induction coil 04 towards the side with higher molten zone.

[0046] For processes requiring fully automated control, the metal purification process using the vertical cold crucible induction melting equipment of this embodiment is as follows: Before operating the equipment, commands regarding vacuum level, inert gas pressure, melting zone width, melting zone movement speed, and number of melting repetitions are input to the control system 12, and the position of limit switch 37 is set on slide rail 36. Then, the quartz furnace tube 13 is removed, and after loading the metal material 02 to be purified into the water-cooled crucible 01, the quartz furnace tube 13 is reinstalled, and the induction coil 04 is moved to the height of the bottom of the water-cooled crucible 01. The subsequent process is automatically executed by the control system according to the set program, including starting the cooling system 11, evacuating the quartz furnace tube 13, or filling the quartz furnace tube 13 with inert gas after evacuation, starting the high-frequency power supply 24 to form a melting zone 03 in the material that meets the melting zone width requirements, and starting the linear drive system 08 to move the induction coil 04 at a specified speed (the melting zone in the material moves along the crucible at the same speed). During operation, the control system 12 automatically adjusts the power supply to maintain the width of the melting zone. When the induction coil 04 reaches the position defined by the limit switch, the control system automatically arranges the induction coil 04 to return to its original position at a relatively fast speed, and then begins the second zone melting process. Following pre-input instructions, the equipment stops operating after the zone melting process has been repeated a specified number of times. Finally, after cooling to the specified temperature, the quartz furnace tube 13 is removed from the vacuum system and cooling system, the water-cooled crucible is taken out, and the purified metal is extracted.

[0047] The device running this embodiment can also issue commands to all or part of the process manually via the touchscreen.

[0048] To better understand this implementation method, some specific embodiments are also provided below: Example 1: The vertical cold crucible induction zone melting and purification equipment of this embodiment consists of several parts: furnace body 05, cold crucible system 06, power supply system 07, linear drive system 08, rotary drive system 09, vacuum system 10, cooling system 11, and control system 12.

[0049] The furnace body 05 consists of three parts: quartz furnace tube 13, furnace tube base 14, and equipment frame 15. Figure 4 The quartz furnace tube has an inner diameter of 100mm and a length of 1000mm.

[0050] The cold crucible system 06 is installed inside the quartz furnace tube 13 and the furnace tube base 14. Figure 4 It consists of a crucible body 01, a water jacket 16, a main water pipe 17, and a water interface 18. The crucible body is vertically mounted inside a quartz furnace tube, with an inner diameter of 60 mm and a height of 800 mm. The crucible has a circular cross-section, divided into 16 segments along its height. Each segment contains a cooling water channel. The water channels in the crucible connect to the cooling system through the water jacket, the main water pipe, a dynamic sealing structure, and the water interface. The water interface in this embodiment adopts... Figure 6The dynamic sealing structure shown is designed to maintain a tight seal while connecting to a fixed water interface as the main water pipe rotates.

[0051] The power supply system 07 consists of a power supply cabinet 24, a flexible cable 25, an induction coil 04, and an induction coil bracket 26. Figure 4 The power supply has a power of 60kW and a frequency of 100kHz. There are two turns of induction coil surrounding the quartz furnace tube, mounted on an induction coil bracket. A camera is also mounted on the bracket for tracking the molten zone.

[0052] Linear drive system 08 ( Figure 4 Mounted on the equipment frame 15, it consists of a stepper motor 27, a reducer 28, a linear module 29, a module base 30, a linear drive head 31, and a controller 32. The motor's rotation is reduced by the reducer, and the linear module converts the rotation into linear motion of the drive rod. The induction coil bracket 26, connected to the drive head, then drives the induction coil 04 to move up and down along the axis of the crucible 01. The linear module of this invention uses... Figure 5 The structure shown comprises a lead screw 33, a nut 34, a drive head 31, a linear bearing 35, and a slide rail 36. A limit switch 37 is mounted on the slide rail of the linear module. In this invention, the limit switch limits a radius of 650 mm. The linear module 29 and module base 30 are mounted on an XY-axis displacement stage 49, which has two positioning directions, X and Y. This stage allows adjustment of the linear module's position on the horizontal plane, i.e., adjusting the relative position of the induction coil to the crucible in the horizontal direction.

[0053] The rotary drive system 09 is installed below the furnace tube base 14. Figure 4 It consists of a rotary drive motor 38, a reducer 39, a transmission device 40, and a rotary drive head 41. The drive motor 38 is also a stepper motor. The rotation of the motor 38 is reduced by the reducer 39, and then transmitted to the drive head 41 by the transmission device 40. The drive head is installed at the lower end of the water main pipe 17 of the crucible 01. When the drive head rotates, it drives the crucible to rotate around the axis through the water main pipe.

[0054] The vacuum system 10 consists of a rotary vane pump, a molecular pump, vacuum valves, and vacuum pipes, with the vacuum pipes connected to the flanges of the furnace tube base.

[0055] The cooling system 11 supplies cooling water to the crucible, induction coil, power supply and vacuum pump.

[0056] The control system 12 is equipped with a PLC module and a touch screen. Its function is to control the operation of the power supply, vacuum system, cooling system, and drive system, and to measure the operating status. Measuring instruments include a vacuum gauge, pressure gauge, thermocouple, and displacement sensor, which can be used to measure vacuum level, gas pressure, cooling water temperature, and molten zone movement speed. In this embodiment, a camera 48 measures the molten zone image, and the video signal is sent to the PLC for image processing to obtain molten zone width data. The PLC compares this data with a pre-input molten zone width command and then adjusts the power supply to achieve closed-loop control of the molten zone width.

[0057] This embodiment employs a program-controlled mode. The PLC pre-sets commands such as a vacuum degree of 5 x 10⁻⁴ Pa, argon filling pressure of 0.02 MPa, melting zone width of 20 mm, melting zone movement speed of 0.05 mm / min, crucible rotation speed of 10 rpm, melting zone stroke of 650 mm, and repeated melting cycles of 6. The position of the limit switch 37 is set on the slide rail 36. Then, the quartz furnace tube 13 is removed, and after loading 99.95% pure sponge titanium 02 into the crucible 01, the quartz furnace tube is reinstalled. The induction coil 04 is moved to the bottom height of the crucible body 01. The subsequent process is automatically executed by the control system according to the set program, including starting the cooling system, evacuating the quartz furnace tube, or, after evacuation, filling the furnace tube with inert gas, starting the high-frequency power supply 24 to form a melting zone 03 in the material that meets the melting zone width requirements, and starting the drive system 08 to move the induction coil at a specified speed (the melting zone in the material moves along the crucible at the same speed). During operation, the control system 12 automatically adjusts the power supply to maintain the width of the melting zone. When the induction coil reaches the position defined by the limit switch, the control system automatically arranges the induction coil to return to its original position at a relatively fast speed, and then begins the second zone melting process. Following pre-input instructions, the equipment stops after the zone melting process has been repeated six times as specified. Finally, after cooling to the specified temperature, the quartz furnace body is removed from the vacuum system and cooling system, the crucible is taken out, and the purified titanium metal is extracted.

[0058] Analysis showed that the purity of Ti was improved to the level of 5N.

[0059] Example 2: The equipment used in this embodiment is the same as that in Embodiment 1. In this embodiment, the material used for purification is metallic cobalt with a purity of 99.9%d. Among the set control parameters, only the width of the melting zone is changed to 25mm, and the other control parameters are the same as those in Embodiment 1.

[0060] After six rounds of zone melting purification, the purity of Co reached 5N.

[0061] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A vertical cold crucible induction zone melting and purification device, characterized in that, It includes a furnace body (05), a cold crucible system (06), a power supply system (07), a linear drive system (08), and a rotary drive system (09). The furnace body (05) includes a quartz furnace tube (13), a furnace tube seat (14), and an equipment frame (15); wherein, the upper end of the quartz furnace tube (13) is sealed, and the lower end is installed on the upper end of the furnace tube seat (14) by vacuum sealing; the lower end face of the furnace tube seat (14) is connected to the rotation drive system (09); the furnace tube seat (14) and the linear drive system (08) are installed on the platform of the equipment frame (15); The cold crucible system (06) includes a water-cooled crucible (01), wherein the water-cooled crucible (01) is vertically installed inside the quartz furnace tube (13) and is composed of several slender petals (19); The power system (07) includes a power cabinet (24), a flexible cable (25), an induction coil (04), and an induction coil bracket (26); wherein, the induction coil (04) is installed around the outside of the quartz furnace tube (13), the induction coil (04) is fixedly connected to the induction coil bracket (26), and the power cabinet (24) is connected to the induction coil (04) through the flexible cable 25. The linear drive system (08) includes a linear drive motor (27), a reducer (28), a linear module (29), and a linear drive head (31). The rotation of the drive motor (27) is reduced by the reducer (28), and the rotation is converted into linear motion of the linear drive head (31) by the linear module (29). The induction coil bracket (26) connected to the linear drive head (31) then drives the induction coil (04) to move up and down along the axis of the water-cooled crucible (01). The rotation drive system (09) is installed below the furnace tube base (14), and includes a rotation drive motor (38), a reducer (39), a transmission device (40), and a rotation drive head (41). The rotation of the drive motor (38) is reduced by the reducer (39) and then transmitted to the rotation drive head (41) by the transmission device (40). The rotation drive head (41) drives the water-cooled crucible (01) to rotate around the axis.

2. The vertical cold crucible induction zone melting and purification equipment according to claim 1, characterized in that, It also includes a vacuum system (10), and the side of the furnace tube seat (14) is connected to the vacuum system (10).

3. The vertical cold crucible induction zone melting and purification equipment according to claim 1, characterized in that, It also includes a cooling system (11), and the cold crucible system (06) also includes a water jacket (16), a water main (17) and a water interface (18). In this crucible, each of the lobes (19) is provided with a cooling water channel (20) extending along the height of the crucible. The water jacket (16) is installed in a sealed manner at the lower end of the water-cooled crucible (01), and the cooling water passage (20) in the water-cooled crucible (01) is connected in a sealed manner to the water jacket (16). A water manifold (17) is installed below the water jacket (16). The water manifold (17) passes through the bottom surface of the furnace tube seat (14) through a vacuum dynamic seal and extends to the bottom of the furnace tube seat (14). The main water pipe (17) includes a concentric inner pipe (21) and an outer pipe (22). In the lower section of the main water pipe (17), the inner pipe (21) and the outer pipe (22) are connected to a water interface (18) through a dynamic sealing structure (23). The water interface (18) is connected to the main water supply pipe and the main water return pipe of the cooling system (11).

4. The vertical cold crucible induction zone melting and purification equipment according to claim 1, characterized in that, The linear module (29) includes a lead screw (33), a nut (34), a linear drive head (31), a linear bearing (35), and a slide rail (36). Among them, a limit switch (37) is installed on the slide rail (36) to limit the travel range of the induction coil (04), and the installation direction of the slide rail (36) is parallel to the axis of the water-cooled crucible (01). The linear module (29) is mounted on the module base (30), and the module base (30) adopts an XY axis displacement stage (49).

5. The vertical cold crucible induction zone melting and purification equipment according to claim 3, characterized in that, The rotating drive head (41) is installed at the lower end of the water main pipe (17) of the water-cooled crucible (01). When the rotating drive head (41) rotates, it drives the water-cooled crucible (01) to rotate around the axis through the water main pipe (17).

6. The vertical cold crucible induction zone melting and purification equipment according to claim 3, characterized in that, The dynamic sealing structure (23) includes a sealing sleeve (42), a sealing ring (43), a nut (44), and a clamping nut (45); Two sealing sleeves (42) are respectively wrapped around the inner pipe (21) and outer pipe (22) of the water main pipe (17) to form an annular cavity (46). The annular cavity (46) is connected to a water hole (47) on the inner pipe (21) or the outer pipe (22). The water interface (18) is installed on the pipe wall of the sealing sleeve (42) and is connected to the annular cavity (46). The sealing sleeve (42) can rotate relative to the inner pipe (21) and outer pipe (22) of the water main pipe (17), and a sealing ring (43) is installed in the gap between the sealing sleeve (42) and the inner pipe (21) and outer pipe (22). The nut (44) presses the sealing ring (43) together, and the tightening nut (45) is used to lock the sealing nut (44).

7. The vertical cold crucible induction zone melting and purification equipment according to claim 2, characterized in that, The vacuum system (10) includes a vacuum pump, vacuum valves and vacuum pipes, which are connected to the interface flange of the furnace tube seat (14).

8. The vertical cold crucible induction zone melting and purification equipment according to any one of claims 1-7, characterized in that, The device is also equipped with a camera (48) mounted on the induction coil bracket (26) to follow the movement of the molten zone (03) and to track and measure the width of the molten zone.

9. The vertical cold crucible induction zone melting and purification equipment according to claim 8, characterized in that, During zone melting, the width of the molten zone (03) is 5mm to 100mm; And / or, the number of turns of the induction coil (04) is 1 turn, 2 turns, or several turns. And / or, the moving speed of the molten zone (03) is 0.01 mm / min to 10 mm / min; And / or, the rotation speed of the drive head (41) is 1 rpm to 120 rpm.

10. The vertical cold crucible induction zone melting and purification equipment according to claim 1, characterized in that, The cross-section of the water-cooled crucible (01) is circular, square, rectangular, polygonal, or other shapes; And / or, the inner diameter of the water-cooled crucible (01) is 10 to 500 mm; And / or, the number of petals (19) of the water-cooled crucible (01) is 6 to 60.

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