A purification device for high-purity aluminum

Abstract

A kind of purification device of high-purity aluminum, pipe rail is installed on base, several mobile seats are slidably installed on pipe rail, mobile seat is connected with the outer wall of quartz tube by support rod, graphite boat is placed in the inner cavity of quartz tube, and aluminum metal to be purified is loaded in graphite boat;Quartz tube passes through melting zone heater, directional solidification heater A, water-cooled copper pipe, directional solidification heater B and zone melting induction heater in turn, water-cooled copper pipe surrounds the outer wall of quartz tube, and circulating cooling water is passed in the inner cavity of pipe.The utility model adopts the composite mode of zone melting technology and directional solidification technology, first carries out directional solidification technology, and impurities are concentrated in a section, and then high-purity aluminum is purified by zone melting method, so that the number of zone melting is reduced, and energy consumption is reduced.Aluminum metal to be purified placed in graphite boat in quartz tube passes through melting heating-electromagnetic stirring-directional solidification (cooling device)-zone melting several steps in turn, and after that, aluminum metal after purification can be obtained, and the whole process is simple and efficient.

Description

Technical Field

[0001] This utility model relates to the technical field of metal purification equipment, specifically a purification equipment for high-purity aluminum. Background Technology

[0002] High-purity aluminum is a high-tech, high-value-added material, primarily used in high-tech fields and scientific research. With the continuous development and upgrading of the manufacturing industry, the demand for high-purity aluminum products is increasing year by year. Currently, there are four main methods for purifying primary aluminum: three-layer electrolysis, organic electrolysis, zone melting, and segregation. Each method corresponds to different processing equipment. However, existing equipment for purifying primary aluminum still suffers from drawbacks such as insufficient purification efficiency, high energy consumption, and complex procedures.

[0003] In recent years, directional solidification and zone melting technologies have attracted much attention. Directional solidification is a process technology that optimizes material microstructure or achieves directional separation of impurities by controlling the solidification direction of molten metal. Its core lies in precisely controlling the temperature gradient and solidification rate to allow the melt to solidify sequentially along a specific direction, thereby regulating crystal growth and impurity distribution.

[0004] Zone melting, through segregation and directional movement of the molten zone, drives impurities to the end of the material for removal, making it a core technology for achieving ultra-high purity aluminum. Its pollution-free and highly flexible characteristics make it irreplaceable in high-end fields such as semiconductors and nuclear industries. In contrast, single-zone melting requires multiple refining processes to purify high-purity aluminum, resulting in disadvantages such as long cycles, high energy consumption, and low production capacity. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention provides a high-purity aluminum purification device that employs a combination of zone melting and directional solidification technologies. First, directional solidification is performed to concentrate impurities in one section, followed by zone melting for high-purity aluminum purification. This reduces the number of zone melting operations and lowers energy consumption. The aluminum metal to be purified, placed in a graphite boat within a quartz tube, undergoes a series of steps: melting and heating, electromagnetic stirring, directional solidification (forced cooling), and zone melting, resulting in purified aluminum metal. The entire process is simple and efficient.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows:

[0007] A high-purity aluminum purification device includes a base with a rail for mounting pipes and several movable seats that slide on the rails. The movable seats are connected to the outer wall of a quartz tube via support rods. A graphite boat is placed inside the quartz tube and loaded with aluminum metal to be purified. The quartz tube passes sequentially through a melting zone heater, an electromagnetic stirrer, a directional solidification heater A, a water-cooled copper tube, a directional solidification heater B, and a zone melting induction heater. The water-cooled copper tube surrounds the outer wall of the quartz tube, and circulating cooling water flows through the inner cavity of the tube.

[0008] The graphite boat inside the quartz tube moves as the quartz tube moves.

[0009] The melting zone heater is a resistance heater with a heating temperature of over 660℃, reaching the melting temperature of aluminum, melting the aluminum into a liquid state, and providing conditions for subsequent directional solidification and zone melting.

[0010] Directional solidification heaters A and B are resistance heaters, forming a directional solidification cooling zone. Heater A has a controlled temperature of 550-600℃, while heater B has a controlled temperature of 50-100℃. The two heaters create two directional solidification zones with a temperature difference greater than 500℃. Heater A acts as a solidification buffer, reducing supercooling caused by forced cooling in the early stages of crystal growth. The main purpose of the slow cooling zone is to create a more stable and gentler temperature field, resulting in columnar or single-crystal structures with more consistent orientation, fewer defects, and higher quality. Molten aluminum passes through heater A, ensuring that the ingot's outer shell is completely solidified before entering the forced cooling zone, while the interior remains a uniformly heated solid, thus preventing deformation and stress. A water-cooled copper pipe is installed between heaters A and B, surrounding the outer wall of the quartz tube, with circulating cooling water flowing through its interior. The circulating cooling water continuously forces cooling down the interior of this section of the quartz tube. The circulating water area and the directional solidification heater B are directional solidification forced cooling areas. As the guide rail moves, the aluminum liquid in the buffer zone passes through the forced cooling area. According to the principle of segregation, the different solubilities of each impurity element in the liquid phase and solid phase are used to purify the aluminum. As the solidification interface moves forward, the discharged impurity elements are continuously enriched in the liquid phase area, eventually causing the impurities to accumulate in one section.

[0011] After passing through the directional solidification zone, the aluminum ingot has already undergone one purification process, causing impurities to accumulate in one section of the graphite boat. No adjustment of the graphite boat's orientation is needed; the continuous movement of the guide rail allows for zone melting purification of the refined aluminum. The zone melting induction heater uses industrial frequency induction heating for zone melting, preventing damage to the device from excessively high temperatures. A cooling water circulation system is installed inside the coil to cool the system. The heating temperature of the zone melting induction heater is above 660℃. After passing through the directional solidification zone, the aluminum ingot is solid, while the metallic aluminum melts in the graphite boat. This portion of the material in the graphite boat after passing through the induction heater is in a solid-liquid coexistence state. When the graphite boat solidifies after passing through this zone, impurities with an equilibrium distribution coefficient less than 1 will move in the opposite direction of the graphite boat's movement, eventually accumulating at one end of the metal rod, thus achieving the purification effect.

[0012] An electromagnetic stirrer is installed between the melting zone heater and the directional solidification heater A, with a quartz tube passing through the inner ring of the electromagnetic stirrer.

[0013] Electromagnetic stirrer principle: The core principle of electromagnetic stirring is to utilize the interaction between an electromagnetic field and a conductive fluid. An alternating magnetic field can be applied outside the furnace, inducing eddy currents in the molten aluminum. The interaction between the eddy currents and the magnetic field generates electromagnetic force, driving the fluid to flow in a specific direction, thus achieving the stirring effect. This device uses a three-phase, six-pole electromagnetic stirrer ring outside a quartz tube. A penetrating low-frequency magnetic field is generated by a three-phase rotating magnetic field coil outside the quartz tube, driving the molten aluminum to rotate.

[0014] The annular electromagnetic stirring coil is positioned between the directional solidification aluminum melt heater and the forced cooling position to prevent damage to the rotating device from the heaters at both ends. A cooling water circulation system is installed inside the rotating device. As the guide rail moves, the molten aluminum is stirred before it enters the cooling zone. This stirring reduces the solute concentration at the solid-liquid interface, promotes the diffusion of solute elements into the liquid phase, and improves the purification effect. Electromagnetic stirring has the advantages of being non-contact, pollution-free, and easy to control.

[0015] The movable base has a wire hole in the middle, through which a lead screw passes. The lead screw is driven by a servo motor. The servo motor applies power to move the quartz tube horizontally by rotating the lead screw.

[0016] Limiting blocks are fixedly installed at both ends of the base, with one end of the bearing connecting screw mounted on the limiting block. The limiting block restricts the extreme positions of the quartz tube's forward and backward translation.

[0017] A graphite sleeve is installed between the molten zone heater and the outer wall of the quartz tube. The graphite sleeve wraps around and adheres to the outer wall of the quartz tube. The graphite sleeve has good thermal conductivity and heat resistance. Through the heat conduction of the graphite sleeve, the heat of the molten zone heater is more evenly conducted to the aluminum in the graphite boat, while also reducing the heat dissipation rate and improving the heat preservation effect.

[0018] The specific implementation steps of this device are as follows:

[0019] 1. After placing the 3N pure aluminum raw material in the graphite boat inside the quartz tube, after purging the air inside the quartz tube, argon or hydrogen is introduced for protection to avoid the accumulation of impurities caused by the formation of an oxide film on the surface of the melt.

[0020] 2. Add aluminum to the graphite boat, wrap the top opening of the graphite boat with copper foil and place it in the quartz tube. The graphite boat is placed at the directional solidification and melting heater. The graphite boat (aluminum metal) moves from the right end of the melting zone heater to the left, and the moving speed is kept at a constant speed of 10mm / h to 15mm / h from beginning to end.

[0021] 3. After the aluminum metal enters the molten zone, the molten zone is heated to 660-800℃. After the aluminum block is completely melted into a liquid state, it is kept at this temperature for 1-1.5 hours.

[0022] 4. Aluminum metal enters the electromagnetic stirring zone from the molten zone along the guide rail, where the molten aluminum is electromagnetically stirred; the electromagnetic stirring frequency is 20Hz. Stirring reduces the solute concentration at the solid-liquid interface, promoting the diffusion of solute elements into the liquid phase.

[0023] 5. Aluminum metal enters the directional solidification cooling zone from the electromagnetic stirring zone. The temperature of directional solidification heater A is set at 25-600℃, and the temperature of solidification heater B is set at 25-100℃, so that the temperature difference between the two heaters is 500℃. This ensures that the aluminum molten metal can ensure that the outer shell of the ingot is completely solidified when it enters the strong cooling zone, while the inside is a uniformly heated solid. The graphite boat completely passes through the cooling zone, completing the directional solidification process and obtaining the aluminum to be melted.

[0024] 6. Turn off all heaters and rotating devices in the directional solidification zone, turn on the zone melting induction heating furnace body device, and continuously move the guide rail to allow the aluminum to be melted to undergo zone melting along the guide rail. The aluminum metal enters the zone melting zone from the directional solidification zone. After the zone melting is completed, remove the aluminum rod from the quartz tube, and then remove the tail end of the aluminum rod to obtain high-purity aluminum of 5N or higher.

[0025] Advantages of utility models:

[0026] 1. This invention involves placing aluminum metal to be purified in a graphite boat inside a quartz tube, and then sequentially passing it through the steps of melting and heating, electromagnetic stirring, directional solidification (cooling device), and zone melting to obtain purified aluminum metal. One pass achieves the effect of two purification processes, increasing raw material utilization, reducing the number of zone melting operations, shortening the purification process time, and reducing energy consumption.

[0027] 2. This utility model stabilizes and strengthens the temperature gradient in front of the solid-liquid interface by adding a slow cooling zone to the forced cooling zone. The slow cooling zone makes the temperature change more gradual, effectively reducing the internal stress generated during solidification and cooling, and making the crystal orientation of the purified metal more consistent. Attached Figure Description

[0028] Figure 1 This is an elevation view of the present utility model;

[0029] Figure 2 This is the front view of the present utility model;

[0030] Figure 3 This is a cross-sectional view of the present invention; (aluminum metal in its initial state).

[0031] Figure 4 This is a cross-sectional view of the present invention; (aluminum metal is in the finished state).

[0032] The numbers and component names in the diagram are as follows: 1-Base; 2-Limiting block; 3-Pipe rail; 41-Screw rod; 42-Servo motor; 51-Quartz tube; 52-Flange cover; 53-Support rod; 54-Moving seat; 55-Graphite boat; 6-Melting zone heater; 61-Graphite sleeve; 7-Electromagnetic stirrer; 81-Directional solidification heater A; 82-Directional solidification heater B; 83-Water-cooled copper tube; 9-Zone melting induction heater. Detailed Implementation

[0033] Example 1

[0034] A high-purity aluminum purification device includes a base 1 with a rail 3 installed on it. Several movable seats 54 are slidably installed on the rail 3. The movable seats 54 are connected to the outer wall of a quartz tube 51 via a support rod 53. A graphite boat 55 is placed inside the quartz tube 51, and the aluminum metal to be purified is loaded in the graphite boat 55. The quartz tube 51 passes sequentially through a melting zone heater 6, an electromagnetic stirrer 7, a directional solidification heater A81, a water-cooled copper tube 83, a directional solidification heater B82, and a zone melting induction heater 9. The water-cooled copper tube 83 surrounds the outer wall of the quartz tube 51, and circulating cooling water flows through the inner cavity of the tube.

[0035] An electromagnetic stirrer 7 is provided between the melting zone heater 6 and the directional solidification heater A81, and a quartz tube 51 passes through the inner ring of the electromagnetic stirrer 7.

[0036] The movable seat 54 has a wire hole in the middle, through which a lead screw 41 is threaded. The lead screw 41 is driven by a servo motor 42.

[0037] Limiting blocks 2 are fixedly installed at both ends of the base 1, and one end of the bearing connecting screw 41 is installed on the limiting block 2 at one end.

[0038] A graphite sleeve 61 is provided between the molten zone heater 6 and the outer wall of the quartz tube 51.

[0039] The lengths of each working zone are as follows: the graphite boat is 20cm long, the melting zone heating zone is 20cm long, the electromagnetic stirring zone is 10cm long, and the melting zone heating zone is 6cm away from the electromagnetic stirring zone; the directional solidification zone is 26cm long, of which the directional solidification zone A is 10cm long, the directional solidification zone B is 10cm long, and the copper tube cooling zone is 6cm long; the directional solidification zone is 6cm away from the electromagnetic stirring zone, the zone melting induction heating zone is 6cm long, and the zone melting induction heating zone is 22cm away from the directional solidification zone.

Claims

1. A high-purity aluminum purification apparatus, characterized in that: A pipe rail (3) is installed on the base (1), and several movable seats (54) are slidably installed on the pipe rail (3). The movable seats (54) are connected to the outer wall of the quartz tube (51) through the support rod (53). A graphite boat (55) is placed in the inner cavity of the quartz tube (51), and the aluminum metal to be purified is loaded in the graphite boat (55). The quartz tube (51) passes through the melting zone heater (6), the electromagnetic stirrer (7), the directional solidification heater A (81), the water-cooled copper tube (83), the directional solidification heater B (82), and the zone melting induction heater (9) in sequence. The water-cooled copper tube (83) surrounds the outer wall of the quartz tube (51), and the inner cavity of the tube is circulated with cooling water.

2. The high-purity aluminum purification apparatus according to claim 1, characterized in that: An electromagnetic stirrer (7) is provided between the melting zone heater (6) and the directional solidification heater A (81), and a quartz tube (51) passes through the inner ring of the electromagnetic stirrer (7).

3. The high-purity aluminum purification apparatus according to claim 1, characterized in that: The movable seat (54) has a wire hole in the middle, through which a lead screw (41) is threaded. The lead screw (41) is driven by a servo motor (42).

4. The high-purity aluminum purification apparatus according to claim 3, characterized in that: The base (1) is fixedly provided with limiting blocks (2) at both ends, and one end of the limiting block (2) is installed with one end of the bearing connecting screw (41).

5. The high-purity aluminum purification apparatus according to claim 1, characterized in that: A graphite sleeve (61) is provided between the molten zone heater (6) and the outer wall of the quartz tube (51).

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