A continuous method for purifying high purity aluminum by crystallization

Abstract

The application discloses a continuous crystallization purification method of high-purity aluminum, which comprises the following steps: S1, pouring an aluminum-containing liquid into a crystallization crucible and controlling the temperature of the aluminum-containing liquid to be above the liquidus of the aluminum liquid; S2, slowly inserting a crystallization shaft into the aluminum-containing liquid; S3, introducing a protective gas into the crystallization crucible, stirring the aluminum-containing liquid, rotating the crystallization shaft, introducing a cooling gas into the crystallization shaft, starting crystallization, and obtaining a crystallization ingot; and S4, after the crystallization is completed, taking out the crystallization ingot from the crystallization crucible with the crystallization shaft, melting, and casting into an ingot to obtain high-purity aluminum. The method has high production efficiency, high controllability and good stability, and is especially suitable for continuous batch production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal purification, and particularly relates to a continuous crystallization purification method for high-purity aluminum. BACKGROUND

[0002] The crystallization method is also known as the rotating segregation technology, and has the advantages of low energy consumption and low cost, and is widely used in developed countries, especially in Japan. In China, the rotating segregation technology is still in its infancy. In China, the segregation method is mainly the directional solidification method.

[0003] The crystallization purification of high-purity aluminum is a process method for preparing high-purity aluminum by utilizing the segregation characteristics of impurity elements in the process of the transformation of aluminum liquid from liquid to solid. The segregation refers to the phenomenon that the composition of solid alloy or metal is different from the original liquid composition in the solidification process of alloy or pure metal. Generally, the content of trace impurity elements in the crystal after solidification is much lower than that of the original aluminum liquid.

[0004] At present, the crystallization purification process of high-purity aluminum generally has the disadvantages of low production efficiency, poor process controllability, poor stability, and the like, and is not conducive to the continuous industrial production. SUMMARY

[0005] The present application aims to solve the above problems in the prior art, and provides a continuous crystallization purification method for high-purity aluminum, which has high production efficiency, high process controllability, good stability, and is particularly suitable for continuous batch production.

[0006] The technical scheme for solving the above technical problems of the present application is as follows:

[0007] A continuous crystallization purification method for high-purity aluminum, comprising:

[0008] S1, pouring an aluminum-containing liquid into a crystallization crucible, and controlling the temperature of the aluminum-containing liquid to be above the liquidus of the aluminum liquid;

[0009] S2, slowly inserting a crystallization shaft into the aluminum-containing liquid;

[0010] S3, introducing a protective gas into the crystallization crucible, stirring the aluminum-containing liquid, rotating the crystallization shaft, and introducing a cooling gas into the crystallization shaft to start crystallization, and obtaining a crystallization ingot;

[0011] S4, after the crystallization is completed, taking out the crystallization ingot from the crystallization crucible with the crystallization shaft, melting, and casting into an ingot to obtain high-purity aluminum.

[0012] Preferably, the method further comprises:

[0013] S5, melting the crystallization ingot, and repeating steps S1-S4 until high-purity aluminum of a required purity grade is obtained.

[0014] Preferably, the temperature of the aluminum-containing liquid in step S1 is controlled at 20±3℃ above the liquidus line of the aluminum liquid.

[0015] Preferably, before pouring the aluminum-containing liquid into the crystallization crucible, the method further comprises:

[0016] Spraying alumina in the crystallization crucible and preheating.

[0017] Preferably, before slowly inserting the crystallization shaft into the aluminum-containing liquid, the method further comprises: spraying BN on the surface of the crystallization shaft and baking at a temperature of 250-400℃.

[0018] Preferably, the speed of inserting the crystallization shaft into the aluminum-containing liquid is ≤10mm / s, and the distance between the lower end surface of the crystallization shaft and the bottom of the crystallization crucible is 250±20mm.

[0019] Preferably, the outer shape of the crystallization shaft is conical with a taper of 0.5-5°.

[0020] Preferably, the protective gas is nitrogen or argon, and the protective gas is circulated intermittently.

[0021] Preferably, step S3 further comprises: heating and holding the protective gas in the crystallization crucible.

[0022] Preferably, the heating temperature of the protective gas is 10±3℃ above the liquidus line of the aluminum liquid. Preferably, the aluminum-containing liquid is stirred by an electromagnetic stirrer, the rotation direction of the crystallization shaft is opposite to the stirring direction of the electromagnetic stirrer, and the rotation speed of the crystallization shaft is synchronized with the stirring speed of the electromagnetic stirrer.

[0023] Preferably, the rotation speed of the crystallization shaft is 200-400r / min.

[0024] Preferably, the temperature of the cooling gas is -30-100℃, and the flow rate is 100-400L / min.

[0025] Preferably, step S4 removes the crystallization ingot from the crystallization crucible with the crystallization shaft, melts, and casts into an ingot to obtain high-purity aluminum, specifically comprising:

[0026] Transferring the crystallization ingot with the crystallization shaft to an aluminum melting furnace for melting to obtain an aluminum liquid;

[0027] Passing the aluminum liquid into a holding furnace for holding until the aluminum liquid in the holding furnace meets the casting requirements, and then flowing the aluminum liquid into a casting system for casting into an ingot.

[0028] Preferably, step S4 further comprises:

[0029] The amount of the molten aluminum in the melting furnace is maintained to be not less than half of the height of the melting furnace, and the temperature of the molten aluminum in the melting furnace is maintained to be 20±3℃ above the liquidus of the molten aluminum.

[0030] The amount of the molten aluminum in the static furnace is maintained to be not less than one third of the height of the static furnace, and the temperature of the molten aluminum in the static furnace is maintained to be 60±3℃ above the liquidus of the molten aluminum.

[0031] Preferably, when the dendritic ingot is transported to the melting furnace along the dendritic axis, the amount of the molten aluminum in the static furnace is pumped back to the melting furnace to accelerate the melting of the dendritic ingot.

[0032] Compared with the prior art, the continuous purification method of high-purity aluminum according to the present application has at least the following beneficial effects:

[0033] The relative linear velocity of the aluminum-containing liquid and the dendritic axis can be increased, so that the diffusion of impurity elements from the front of the solid-liquid phase interface to the liquid phase during the dendritic process is more effectively promoted, and further diffusion to the vicinity of the crucible wall under the action of centrifugal force is promoted, so that the purification effect of the dendritic process is significantly improved;

[0034] The control range of the temperature gradient and the cooling capacity can be greatly expanded, the controllability of the dendritic rate and the dendritic purity is effectively improved, and the batch stability of the dendritic efficiency and the dendritic purity is significantly improved;

[0035] The transportation efficiency of the dendritic axis can be greatly improved, and the whole process of continuous operation from high-purity aluminum dendritic process, melting to melting and casting preparation is realized, so that the controllability and efficiency rhythm of the process are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The flow chart of the continuous purification method of high-purity aluminum in the embodiment of the present application;

[0037] Figure 2 The structural schematic diagram of the device used in the continuous purification method of high-purity aluminum in the embodiment of the present application;

[0038] Figure 3 The structural schematic diagram of the dendritic device (when the quick connector mechanism locks the dendritic axis) in the embodiment of the present application;

[0039] Figure 4 The structural schematic diagram of the dendritic device (when the quick connector mechanism releases the dendritic axis) in the embodiment of the present application.

[0040] In the figure: 1. crystallization furnace; 2. double chamber furnace; 3. rotary lifting device; 4. crystallization device; 5. base; 6. column rotating mechanism; 6-1. column rotating motor; 7. cantilever lifting mechanism; 7-1. cantilever lifting motor; 8. column; 8-1. upper limit; 8-2. lower limit; 9. cantilever; 10. crystallization rotating mechanism; 10-1. crystallization rotating motor; 11. second boom; 12. crystallization crucible; 13. crucible heater; 14. electromagnetic stirrer; 15. aluminum-containing liquid; 16. crystallization ingot; 17. eddy current refrigerator; 17-1. flow valve; 17-2. temperature valve; 17-3. air inlet; 18. rotary joint; 19. rotary main shaft; 19-1. first air inlet channel; 20. heat insulation gasket; 21. quick mounting shaft; 22. quick mounting clamping mechanism; 22-1. clamping locking mechanism; 22-2. quick mounting clamping jaw; 22-3. convex sealing ring; 23. support beam; 23-1. lifting hole; 23-2. quick mounting shaft through hole; 24. first boom; 24-1. single-sided locking movable pin; 24-2. double-sided locking fixed pin; 25. first furnace cover; 26. first heater; 27. quick mounting joint; 27-1. concave sealing groove; 28. crystallization shaft seat; 28-1. shaft seat flange; 29. shaft sleeve; 29-1. high-temperature-resistant non-stick aluminum shaft sleeve; 29-2. high-purity graphite shaft sleeve; 30. mandrel; 31. loop through hole; 32. heat dissipation fin; 33. plug; 34. shaft sleeve sealing cover; 35. exhaust passage; 36. second air inlet channel; 37. cooling channel; 38. aluminum melting furnace; 39. standing furnace; 40. second furnace body; 41. third furnace cover; 42. second furnace cover; 42-1. air cylinder; 43. fixed support mechanism; 43-1. movable support adapting mechanism; 44. first immersion heater; 45. first plug rod; 46. second plug rod; 47. third plug rod; 48. first radiant heater; 49. second immersion heater; 50. second radiant heater; 51. third immersion heater; 52. crystallization shaft; 53. pump; 54. aluminum outlet; 55- first channel; 56- second channel; 57- furnace wall. DETAILED DESCRIPTION

[0041] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0042] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience and simplification of description, and do not indicate or imply that the devices or elements referred to must be provided with a particular orientation, constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0043] In the description of the present application, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can include one or more of the features explicitly or implicitly. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0044] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection", "arrangement", "installation", "fixation" and the like should be broadly understood, for example, it can be fixedly connected or detachably connected, or integrally connected; it can be directly connected or indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] Embodiment 1

[0046] As shown in Figure 1 , Figure 2 , the present embodiment discloses a continuous crystallization purification method of high-purity aluminum, comprising:

[0047] S1, pouring the aluminum-containing liquid 15 into the crystallization crucible 12 in the crystallization furnace, and controlling the temperature of the aluminum-containing liquid 15 to be above the liquidus of the aluminum liquid;

[0048] S2, transferring the crystallization device 4 to the upper part of the crystallization furnace 1 by the rotating lifting device 3, and slowly inserting the crystallization shaft 52 in the crystallization device 4 into the aluminum-containing liquid 15;

[0049] S3, introducing a protective gas into the crystallization crucible 12 to prevent and slow down the oxidation of the surface of the aluminum-containing liquid 15, stirring the aluminum-containing liquid 15, rotating the crystallization shaft 52, and introducing a cooling gas into the crystallization shaft 52, starting crystallization, and obtaining a crystallization ingot 16;

[0050] S4, after the crystallization is completed, the crystallization ingot 16 is taken out from the crystallization crucible 12 with the crystallization shaft 52, melted, and cast into an ingot to obtain high-purity aluminum.

[0051] In some embodiments, the method further comprises:

[0052] S5, the crystal precipitation ingot 16 is melted, and steps S1-S4 are repeated for further crystal precipitation purification until a high-purity aluminum of a desired purity level is obtained.

[0053] In this embodiment, the aluminum-containing liquid 15 is an aluminum liquid with a purity of no less than 4N6, and specifically, can be any one of 99.996%, 99.997%, 99.998%, 99.999%, 99.9991%, 99.9992%, 99.9993%, 99.9994%, or 99.9995%.

[0054] In this embodiment, the temperature of the aluminum-containing liquid 15 in step S1 is controlled to be within a range of 20±3°C above the liquidus of the aluminum liquid, and specifically, can be any one of 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, or 23°C.

[0055] In this embodiment, before the aluminum-containing liquid 15 is poured into the crystal precipitation crucible 12, it further includes spraying alumina in the crystal precipitation crucible 12 and preheating. The sprayed alumina can prevent the aluminum-containing liquid from being contaminated and mitigate the erosion of the aluminum-containing liquid to the crystal precipitation crucible 12, prolonging the service life of the crucible. The thickness of the alumina is preferably 10-25 μm to ensure the minimum thickness that meets the number of times of crystal precipitation. The preheating temperature is preferably 650-700°C. The preheating can make the temperature of the crystal precipitation crucible 12 close to that of the aluminum-containing liquid, preventing the crystal precipitation crucible from being suddenly cooled or heated, which shortens the service life.

[0056] In this embodiment, before the crystal precipitation shaft 52 is slowly inserted into the aluminum-containing liquid, it further includes spraying BN (boron nitride) on the surface of the crystal precipitation shaft, and the thickness of the BN is preferably 5-10 μm, and baking. The baking temperature is 250-400°C, and specifically, can be any one of 250°C, 280°C, 310°C, 340°C, 370°C, or 400°C. The baking time is preferably about 10 min. By spraying boron nitride, the demolding effect can be achieved to separate the crystal precipitation ingot from the crystal precipitation shaft 52.

[0057] In this embodiment, the speed at which the crystal precipitation shaft 52 is inserted into the aluminum-containing liquid 15 is preferably ≤10 mm / s, and specifically, can be any one of 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, 5 mm / s, 6 mm / s, 7 mm / s, 8 mm / s, 9 mm / s, or 10 mm / s.

[0058] By slowly inserting the crystal precipitation shaft 52 into the aluminum-containing liquid 15, it can ensure that the impurity elements have sufficient time to diffuse into the aluminum-containing liquid, thereby ensuring the purity of the crystal precipitation ingot obtained in subsequent crystal precipitation. In addition, by selecting the above insertion speed range, the preparation time can be shortened as much as possible while ensuring that the impurity elements have time to diffuse.

[0059] In the embodiment, the distance between the lower end surface of the crystallization shaft 52 and the bottom of the crystallization crucible 12 is 250±20mm, specifically, it can be any distance among 230mm, 240mm, 250mm, 260mm or 270mm, which is selected and set according to the growth rate of the crystallization ingot and the effective diffusion distance of the elements.

[0060] By controlling the distance between the lower end surface of the crystallization shaft 52 and the bottom of the crystallization crucible 12, not only can the growth space of the crystallization ingot be ensured, but also the impurity elements deposited by diffusion at the bottom of the crucible can be kept a certain distance from the bottom end of the crystallization ingot, ensuring the purity of the crystallization ingot.

[0061] In the embodiment, the protective gas is nitrogen or argon, of course, it can also be any other gas that does not react with aluminum, and the protective gas is circulated intermittently.

[0062] Specifically, when argon is used as the protective gas, the pressure of the protective gas is preferably 0.1-0.3MPa, the flow rate is preferably 5-15L / min, the ventilation mode is open for 1-3min, close for 1-3min, then open for 1-3min, and so on. More preferably, the pressure of the protective gas is 0.15-0.2MPa, the flow rate is 7-10L / min, the ventilation mode is open for 1.5-2min, close for 1.5-2min, then open for 1.5-2min, and so on.

[0063] When nitrogen is used as the protective gas, the pressure of the protective gas is preferably 0.1-0.3MPa, the flow rate is preferably 10-30L / min, the ventilation mode is open for 1-5min, close for 1-3min, then open for 1-5min, and so on. More preferably, the pressure of the protective gas is 0.2-0.25MPa, the flow rate is 20-25L / min, the ventilation mode is open for 3-5min, close for 1-2min, then open for 3-5min, and so on.

[0064] The purity of argon or nitrogen is not less than 99.999%.

[0065] In the embodiment, the step S3 further comprises heating and holding the protective gas in the crystallization crucible 12 to maintain the temperature of the atmosphere above the aluminum-containing liquid in the crystallization crucible.

[0066] Specifically, the heating temperature of the protective gas is preferably 10±3℃ above the liquidus of the aluminum liquid, for example, it can be any temperature among 7℃, 8℃, 9℃, 10℃, 11℃, 12℃ or 13℃.

[0067] In the embodiment, the aluminum-containing liquid is stirred by the electromagnetic stirrer 14, the rotating direction of the crystallization shaft 52 is opposite to the stirring direction of the electromagnetic stirrer 14, the rotating speed of the crystallization shaft 52 is synchronous with the stirring speed of the electromagnetic stirrer 14, so that the crystallization shaft 52 and the electromagnetic stirrer 14 move synchronously and reversely along the circumferential trajectory.

[0068] Specifically, the power frequency of the electromagnetic stirrer 14 is preferably 20-50 Hz, the current intensity is preferably 500-3000 A, and the rotating speed of the crystallization shaft 52 is preferably 200-400 r / min. More preferably, the power frequency of the electromagnetic stirrer 14 is 30-45 Hz, specifically any one of 30 Hz, 33 Hz, 36 Hz, 39 Hz, 42 Hz or 45 Hz; the current intensity of the electromagnetic stirrer 14 is 1000-1800 A, specifically any one of 1000 A, 1200 A, 1400 A, 1600 A or 1800 A; and the rotating speed of the crystallization shaft 52 is 250-350 r / min, specifically any one of 250 r / min, 270 r / min, 290 r / min, 310 r / min, 330 r / min or 350 r / min.

[0069] In the embodiment, the temperature of the cooling gas is -30-100 ℃, the flow rate is 100-400 L / min, and the feeding time of the cooling gas is 30-180 min.

[0070] Preferably, the temperature of the cooling gas is 0-70 ℃, the flow rate is 500-3000 L / min, and the feeding time (i.e. the feeding time of the cooling gas) is 60-150 min.

[0071] More preferably, the temperature of the cooling gas is 25-45 ℃, specifically any one of 25 ℃, 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃, 40 ℃ or 45 ℃; the flow rate of the cooling gas is 1500-2500 L / min, specifically any one of 1500 L / min, 1700 L / min, 1900 L / min, 2100 L / min, 2300 L / min or 2500 L / min; and the feeding time is 80-120 min, specifically any one of 80 min, 90 min, 100 min, 110 min or 120 min.

[0072] In the embodiment, as shown in FIG. 2, the crystallization shaft 52 is arranged in the crystallization tank 10, and the electromagnetic stirrer 14 is arranged in the crystallization tank 10. Figure 2As shown, the crystallization furnace comprises a first furnace body, a first furnace cover 25, and an electromagnetic stirrer 14. The first furnace cover is connected with a support beam 23 located directly above the first furnace cover 25 through a first hanger 24, so that the first furnace cover 25 is suspended on the first furnace body. The support beam 23 is provided with a hanger hole 23-1, and the hanger hole 23-1 is provided with a second hanger 11. The support beam 3 is connected with a cantilever 9 in the rotary lifting device 3 through the second hanger 11. The electromagnetic stirrer 14 is arranged at the bottom of the first furnace body.

[0073] Specifically, the first hanger 24 and the first furnace cover 25 are connected and fixed by using double-sided locking fixing pins 24-2, and the first hanger 24 and the support beam 23 are connected and fixed by using a single-sided locking movable pin 24-1. The first furnace body comprises a crystallization crucible 12 and a crucible heater 13. The crucible heater 13 is arranged outside the crystallization crucible 12 and circumferentially surrounds the crystallization crucible 12. The electromagnetic stirrer 14 is located at the bottom of the crystallization crucible 12. The first furnace cover 25 is adapted to the crystallization crucible 12. The first furnace cover 25 is provided with a protective gas inlet for introducing the protective gas into the crystallization crucible, so as to prevent and slow down the oxidation of the surface of the aluminum-containing liquid.

[0074] The first furnace cover 25 is embedded with a first heater 26. The first heater 26 preferably adopts any commercially available heat radiation heater with temperature measurement and control functions, so as to heat and keep warm the introduced protective gas through the first heater, and further control the temperature of the protective gas above the aluminum-containing liquid in the crystallization crucible to be 10±3℃ above the liquidus temperature of the aluminum liquid.

[0075] In the embodiment, as shown, Figure 2 The rotary lifting device 3 comprises a base 5, a stand column 8, a stand column rotating mechanism 6, a stand column rotating motor 6-1, a cantilever 9, a cantilever lifting mechanism 7, and a cantilever lifting motor 7-1. The bottom end of the stand column 8 is arranged on the base 5. One end of the cantilever 9 is connected with the stand column 8. The crystallization device 4 is arranged on the other end of the cantilever 9. The stand column rotating mechanism 6 is connected with the stand column 8. The stand column rotating motor 6-1 is connected with the stand column rotating mechanism 6. The stand column rotating motor 6-1 drives the stand column rotating mechanism 6 to rotate the stand column 8, so as to drive the crystallization device 4 to rotate to the position of the crystallization furnace 1 or the double-chamber furnace 2, and realize the switching of the equal-radius position. The cantilever 9 is connected with the stand column 8 through the cantilever lifting mechanism 7. The cantilever lifting motor 7-1 is arranged at the top end of the stand column 8 and connected with the cantilever lifting mechanism 7. The cantilever lifting motor 7-1 drives the cantilever lifting mechanism 7 to lift the cantilever 9 on the stand column 8, so as to adjust the position height of the crystallization device.

[0076] Specifically, the upright column 8 is further provided with a limiting component. The limiting component specifically includes an upper limiting part 8-1 and a lower limiting part 8-2, the upper limiting part 8-1 is arranged at the limit position of the upward movement of the cantilever 9, and the lower limiting part 8-2 is arranged at the limit position of the downward movement of the cantilever 9, thereby playing a protective role of preventing the cantilever from being separated from the upright column and avoiding the bottom of the crystallization device from colliding with the bottom of the crystallization furnace. The upright column rotating motor 6-1 adopts a first servo motor and a first speed reducer to control the rotation angle; the cantilever lifting motor 7-1 adopts a second servo motor and a second speed reducer to control the lifting height.

[0077] The crystallization device 4 specifically includes a crystallization shaft 52, a quick connector mechanism 22, and a crystallization rotating mechanism 10. The top end of the crystallization shaft 52 is connected to the crystallization rotating mechanism 10 through the quick connector mechanism 22, the crystallization rotating mechanism 10 is arranged on the cantilever 9 in the rotating and lifting device 3, the bottom end of the crystallization shaft 52 penetrates through the first furnace cover 25 of the crystallization furnace 1 and extends into the first furnace body, the crystallization rotating mechanism 10 is connected to a crystallization rotating motor 10-1, the crystallization rotating motor 10-1 can be arranged on the cantilever 9, the crystallization rotating mechanism 10 drives the crystallization shaft 52 to rotate synchronously under the drive of the crystallization rotating motor 10-1, the rotation speed of the crystallization shaft 52 is preferably 0-500 r / min, which can be adjusted arbitrarily according to actual conditions, and the rotation direction of the crystallization shaft 51 is opposite to the stirring direction of the electromagnetic stirrer 14, that is, the rotation direction of the crystallization shaft 52 is opposite to the direction of the movement of the aluminum-containing liquid driven by the electromagnetic stirrer 4. In addition, the movement speed of the aluminum-containing liquid 15 is preferably equal to the radius line speed of the crystallization shaft 52, thereby synchronously, rapidly and reversely stirring the aluminum-containing liquid in the crystallization furnace, increasing the relative linear speed of the aluminum-containing liquid 15 and the crystallization shaft 52, more effectively promoting the impurity elements in the aluminum-containing liquid to diffuse from the front of the solid-liquid phase interface to the liquid phase in the crystallization process, and further diffuse to the vicinity of the inner wall of the crystallization furnace under the action of centrifugal force, thereby significantly improving the crystallization purification effect.

[0078] More specifically, as shown in FIG. 1, the crystallization device 4 is arranged in the crystallization furnace 1, and the crystallization device 4 is arranged in the crystallization furnace 1. Figure 2 , 3As shown in FIGS. 4, the crystallization rotating mechanism 10 includes a rotating main shaft 19, a quick-mounting shaft 21, a quick-mounting joint mechanism 22 including a clamping locking mechanism 22-1 and a quick-mounting clamping jaw 22-2. The rotating main shaft 19 is installed on the cantilever 9 in the rotating lifting device 3 and can rotate under the driving of a crystallization rotating motor 10-1. The top end of the quick-mounting shaft 21 penetrates through a quick-mounting shaft through hole 23-1 in a support beam 23 and is connected to the lower end of the rotating main shaft 19 and rotates together with the rotating main shaft 19. The quick-mounting clamping jaw 22-2 is installed at the bottom end of the quick-mounting shaft 21 through the clamping locking mechanism 22-1. The top end of the crystallization shaft 52 is clamped in the quick-mounting clamping jaw 22-2 and is locked and fixed through the clamping locking mechanism 22-1, and is convenient to install and replace. A heat insulation sealing pad 20 is arranged between the rotating main shaft 19 and the support beam 23. The top of the rotating main shaft 19 is provided with a rotating joint 18 to connect the crystallization rotating motor 10-1. The bottom end edge of the quick-mounting shaft 221 is outwardly protruded to install the quick-mounting clamping jaw 22-2.

[0079] In the embodiment, the crystallization shaft 52 specifically includes a crystallization shaft seat 28, a shaft sleeve 29, a mandrel 30, and a shaft sleeve sealing cover 34. The mandrel 30 penetrates through the crystallization shaft seat 28. The top of the mandrel 30 is provided with a quick-mounting interface 27 which is matched with the quick-mounting clamping jaw 22-2 to be clamped in the quick-mounting clamping jaw. The bottom end of the mandrel 30 is provided with a plug 33 which is preferably threadedly connected with the mandrel 30 or integrally designed. The shaft sleeve 29 is sleeved on the mandrel 30 and below the crystallization shaft seat 28. The shaft sleeve sealing cover 34 is sealed in the through hole on the bottom end of the shaft sleeve 29.

[0080] The bottom end of the quick-mounting shaft 21 is provided with a convex sealing ring 22-3 which can resist high temperature. The top end of the mandrel 30 is provided with a concave sealing groove 27-1 which can resist high temperature and is matched with the convex sealing ring 22-3. It should be noted that the bottom end of the quick-mounting shaft 21 can be provided with a concave sealing groove 27-1 which can resist high temperature and the top end of the mandrel 30 can be provided with a convex sealing ring 22-3 which can resist high temperature.

[0081] And the crystallization device 4 also includes a cooling mechanism, the rotating spindle 19 and the quick mounting shaft 21 are provided with a first air inlet channel 19-1, the cooling mechanism is communicated with the first air inlet channel 19-1, and cooling gas is introduced into the first air inlet channel 19-1 through the cooling mechanism; the mandrel 30 is provided with a second air inlet channel 36, the second air inlet channel 36 is communicated with the first air inlet channel 19-1, the mandrel 30 is provided with a loop through hole 31, a cooling channel 37 is arranged between the mandrel 30 and the sleeve 29, the loop through hole 31 is communicated with the second air inlet channel 36 and the cooling channel 37, and the crystallization shaft seat 28 is provided with an exhaust channel 35. The cooling gas introduced by the cooling mechanism first enters the first air inlet channel 19-1, then enters the second air inlet channel 36, then enters the cooling channel 37 through the loop through hole 31, and finally is discharged through the exhaust channel 35. The cooling gas is cooled to the sleeve 29 in the flow process in the crystallization shaft 52, so that the aluminum liquid is crystallized to obtain a crystallization ingot.

[0082] Specifically, the cooling mechanism includes an eddy current refrigerator 17, a temperature control valve 17-1 and a flow valve 17-2, the gas outlet 17-3 of the eddy current refrigerator 17 is communicated with the first air inlet channel 19-1, and the temperature control valve 17-1 and the flow valve 17-2 are arranged on the gas inlet 17-3 of the eddy current refrigerator 17. The gas (preferably compressed gas with a certain pressure) enters the gas inlet 17-3 of the eddy current refrigerator, and the cooling gas with the required temperature is output at the gas outlet of the eddy current refrigerator 17 after being adjusted by the temperature control valve 17-1 and the flow valve 17-2. In this embodiment, the temperature of the gas introduced into the eddy current refrigerator is preferably adjustable within the range of-45 to 125 DEG C, and the flow of the gas is preferably adjustable within the range of 25 to 4245 L / min.

[0083] The cooling mechanism can also include an automatic controller (not shown in the figure), which is connected with the temperature control valve 17-1 and the flow valve 17-2 respectively, and has an automatic control program preset therein, so as to automatically control the temperature and flow of the cooling gas to change linearly with the introduction time of the cooling gas. Specifically, the automatic controller can be an intelligent terminal device with a man-machine interface, which can automatically adjust the temperature control valve 17-1 and the flow valve 17-2 by inputting the temperature and flow parameters of the cooling gas and the crystallization time (i.e. the introduction time) into the man-machine interface, so as to realize dynamic control of the temperature and flow of the cooling gas with the passage of time.

[0084] The shaft sleeve 29 is a combination of a high-temperature-resistant non-stick aluminum shaft sleeve 29-1 and a high-purity graphite shaft 29-2, that is, it includes a high-temperature-resistant non-stick aluminum shaft sleeve 29-1 and a high-purity graphite shaft 29-2, and the high-temperature-resistant non-stick aluminum shaft sleeve 29-1 is connected with the high-purity graphite shaft 29-2. The high-temperature-resistant non-stick aluminum shaft sleeve 29-1 is located at one end close to the top end of the mandrel 30, and is preferably threadedly connected with or integrally designed with the crystallization shaft seat 8, and the high-purity graphite shaft 29-2 is located at one end close to the bottom end of the mandrel 30.

[0085] The mandrel 30 is provided with a heat dissipation fin 32, and the heat dissipation fin 32 is spirally arranged along the length direction of the mandrel 30, so that the cooling channel 37 is spiral-shaped.

[0086] The number of exhaust channels 35 is one or more groups, for example, six groups. The multiple groups of exhaust channels 35 are centrally and symmetrically distributed along the mandrel 30. The outlet position of the exhaust channel 35 is not lower than 50 mm above the upper cover surface 50 of the first furnace cover 25.

[0087] Compared with the prior art, by arranging the vortex refrigeration device 17 and the heat dissipation fin 32, the temperature gradient and the cooling capacity of the crystallization shaft can be greatly expanded, the controllability of the crystallization rate and the crystallization purity can be effectively improved, and the batch stability of the crystallization efficiency and the crystallization purity can be significantly improved.

[0088] In the embodiment, the shape of the shaft sleeve 29 is preferably conical, and the taper is 0.5-5°, preferably 1-3° or 1.5-2.5°, specifically, it can be any one of 1.5°, 1.6°, 1.7°, 1.8°, 1.9°, 2.0°, 2.1°, 2.2°, 2.3°, 2.4° or 2.5°.

[0089] In the embodiment, the step S4 takes out the crystallization ingot with the crystallization shaft 52 from the crystallization crucible 12, melts, and casts into an ingot to obtain high-purity aluminum, specifically including:

[0090] The crystallization ingot is transported with the crystallization shaft 52 to the aluminum melting furnace 38 for melting to obtain molten aluminum;

[0091] The molten aluminum is introduced into the holding furnace 39 for heat preservation, and after the molten aluminum in the holding furnace 39 reaches the casting requirement, the molten aluminum is flowed into the casting system to be cast into an ingot.

[0092] In some embodiments, the step S4 specifically further includes:

[0093] The inventory of the molten aluminum in the aluminum melting furnace 38 is maintained to be not less than one-half of the hearth height of the aluminum melting furnace, and the temperature of the molten aluminum in the aluminum melting furnace is maintained to be 20±3℃ above the liquidus of the molten aluminum, specifically, it can be any one of 17℃, 18℃, 19℃, 20℃, 21℃, 22℃ or 23℃.

[0094] The amount of the molten aluminum in the holding furnace 39 is maintained to be not less than one third of the height of the holding furnace, and the temperature of the molten aluminum in the holding furnace is maintained to be 60±3℃ above the liquidus of the molten aluminum, specifically, any one of 57℃, 58℃, 59℃, 60℃, 61℃, 62℃ or 63℃.

[0095] In some embodiments, when the crystal separation ingot is transported to the melting furnace 38 along the crystal separation shaft 52 for melting, the amount of the molten aluminum in the holding furnace 39 is pumped back to the melting furnace 38 to accelerate the melting of the crystal separation ingot by using the high-temperature amount of the molten aluminum in the holding furnace.

[0096] In the present embodiment, the steps S4 and S5 are completed in the double-chamber furnace 2, which includes the melting furnace 38 and the holding furnace 39. The melting furnace 38 is used for melting the crystal separation ingot 16, which includes a second furnace body 40, a second furnace cover 42, a second heater, and a first stopper rod 45, and the holding furnace 39 includes a third furnace body, a third furnace cover 41, a third heater, a second stopper rod 46, a third stopper rod 47, and a pump 53.

[0097] Specifically, the second furnace cover 42 is arranged on the second furnace body 40, and the second furnace cover 42 is provided with an opening which is matched with the crystal separation shaft seat 28 so as to suspend the crystal separation shaft 52 with the crystal separation ingot in the second furnace body. The second heater is connected with the second furnace body for heating the crystal separation ingot melted in the second furnace body. The second furnace body 40 is communicated with the third furnace body through a first channel 55 for passing the molten aluminum melted in the second furnace body into the third furnace body, and the first stopper rod 45 extends into the second furnace body through the second furnace cover 42 to block the entrance of the first channel 55 for controlling the opening and closing of the first channel. The third furnace cover 41 is arranged on the third furnace body, and the third heater is connected with the third furnace body for heating and keeping warm the molten aluminum in the third furnace body. The third furnace body is further communicated with the second furnace body 40 through a second channel 56 which is below the first channel 55, and the pump 53 is arranged on the second channel 56 for pumping the molten aluminum in the third furnace body back into the second furnace body 40 to accelerate the melting of the crystal separation ingot. The second stopper rod 46 extends into the third furnace body through the third furnace cover to block the entrance of the second channel 56 for controlling the opening and closing of the second channel. The third furnace body is further provided with an aluminum outlet 54, and the third stopper rod 47 extends through the third furnace cover to block the aluminum outlet 54 for controlling the opening and closing of the aluminum outlet.

[0098] More specifically, the first stopper rod 45, the second stopper rod 46 and the third stopper rod 47 are respectively provided with a silicon nitride sheath. The pump 53 is preferably a magnetic pump.

[0099] Specifically, as shown in FIG. 2, the crystal separation shaft 52 is arranged in the double-chamber furnace 2, and the crystal separation shaft 52 is provided with a crystal separation ingot 16. Figure 2As shown, the aluminum melting furnace 38 and the settling furnace 39 preferably adopt an integrated structure, that is, the second furnace body 40 and the third furnace body are connected as one piece and separated by the furnace wall 57. The inner lining of the second furnace body and the third furnace body are both made of alumina bricks.

[0100] More specifically, such as Figure 2 As shown, the second furnace cover 42 is an automatically opening and closing furnace cover, which includes a first cover body, a second cover body, a fixed support mechanism 43, a movable support adapter mechanism 43-1, and a cylinder 42-1. The first cover body is fixed to the second furnace body 40, and the second cover body is connected to the cylinder 42-1 through a matching linkage mechanism. The cylinder 42-1 drives the second cover body to move, thereby realizing the automatic opening and closing of the second furnace cover 42. The fixed support mechanism 43 and the movable support adapter mechanism 43-1 constitute the opening on the second furnace cover 42. Specifically, when the cylinder 42-1 drives the second cover body to move towards the first cover body and assembles with the first cover body, the second furnace cover 42 closes; when the cylinder 42-1 drives the second cover body to move away from the first cover body, the second cover body separates from the first cover body, and the second furnace cover 42 opens. The fixed support mechanism 43 is located on the first cover, and the movable support adapter mechanism 43-1 is located on the second cover. The crystallization shaft seat 28 is provided with a shaft seat flange 28-1, which is adapted to the fixed support mechanism 43. When the rotary lifting device 3 transfers the crystallization ingot 16 together with the crystallization shaft 52 to the double chamber furnace 2, the crystallization shaft 52 is supported and suspended on the fixed support mechanism 43 by the shaft seat flange 28-1, and the crystallization shaft is locked by the movable support adapter mechanism 43-1 in cooperation with the fixed support mechanism.

[0101] More specifically, such as Figure 2 As shown, the third furnace cover 41 is an integrated heat-insulating furnace cover. Furthermore, since the aluminum melting furnace 38 and the settling furnace 39 are of integrated structure, the integrated heat-insulating furnace cover can be further extended to the position of the second cover body; that is, the third furnace cover and the second cover body can be merged into one unit (e.g., Figure 2 (As shown).

[0102] More specifically, such as Figure 2As shown, the second heater includes the first radiant heater 48, the first immersion heater 44, and the second immersion heater 49. The first radiant heater 48, the first immersion heater 44, and the second immersion heater 49 are arranged in the second furnace body 40, wherein: the first radiant heater 48 is arranged transversely along the upper side of the wall of the second furnace body 40 for heating the ambient temperature above the liquid surface of the molten aluminum in the molten aluminum furnace 38; the first immersion heater 44 is arranged longitudinally along the wall of the second furnace body 40; and the second immersion heater 49 is arranged transversely along the lower side of the wall of the second furnace body 40 for heating the temperature of the molten aluminum in the molten aluminum furnace 38. Through the above configuration, on the one hand, the temperature of the molten aluminum and the atmosphere temperature above the molten aluminum can be independently controlled to accelerate the melting and stripping efficiency of the segregation ingot, and on the other hand, the heating temperature can be adjusted according to the aluminum melting time to save energy consumption. The number of the first radiant heater 48, the first immersion heater 44, and the second immersion heater 49 is one or more, preferably multiple, and the specific number can be selected according to the actual situation, which will not be described one by one in the embodiment. The first radiant heater 48, the first immersion heater 44, and the second immersion heater 49 are respectively provided with a silicon nitride sheath.

[0103] More specifically, as shown, Figure 2 The third heater includes the second radiant heater 50 and the third immersion heater 51. The second radiant heater 50 and the third immersion heater 51 are transversely arranged in the third furnace body, wherein: the second radiant heater 50 is arranged transversely along the upper side of the wall of the third furnace body for heating the ambient temperature above the liquid surface of the molten aluminum in the holding furnace 39; and the third immersion heater 51 is arranged transversely along the lower side of the wall of the third furnace body for heating the temperature of the molten aluminum in the holding furnace 39. Through the above configuration, on the one hand, the temperature of the molten aluminum and the atmosphere temperature can be independently controlled, and on the other hand, it is convenient to flexibly adjust according to the casting temperature and the melting temperature of the segregation ingot. The number of the second radiant heater 50 and the third immersion heater 51 is one or more, preferably multiple, and the specific number can be selected according to the actual situation, which will not be described one by one in the embodiment. The second radiant heater 50 and the third immersion heater 51 are respectively provided with a silicon nitride sheath.

[0104] In some embodiments, the double-chamber furnace 0 further includes a temperature control system (not shown in the figure) electrically connected with the first heater (i.e. the first radiant heater 48, the first immersion heater 44, and the second immersion heater 49) and the second heater (the second radiant heater 50 and the third immersion heater 51). The heating temperature threshold of each first heater and second heater is preset in the temperature control system (specifically set according to the actual process requirements), so as to automatically control the first heater and the second heater to start and stop according to the process requirements, thereby controlling the temperature of the molten aluminum in the molten aluminum furnace and the holding furnace.

[0105] The continuous crystallization purification method of high-purity aluminum of the embodiment has at least the following advantages compared with the prior art:

[0106] By utilizing the synchronous reverse movement of the electromagnetic stirrer and the crystallization rotating mechanism, the relative linear velocity of the aluminum-containing liquid and the crystallization shaft can be increased, thereby more effectively promoting the diffusion of impurity elements from the front of the solid-liquid phase interface to the liquid phase during the crystallization process, and further diffusing to the vicinity of the crucible wall under the action of centrifugal force, significantly improving the crystallization purification effect;

[0107] By the vortex refrigerator and the heat dissipation fins, the temperature gradient and the cooling capacity can be greatly expanded, the controllability of the crystallization rate and the crystallization purity can be effectively improved, and the batch stability of the crystallization efficiency and the crystallization purity can be significantly improved;

[0108] By the rotating lifting device cooperating with the crystallization device, the rotation angle and the lifting height of the crystallization shaft can be quickly and accurately positioned, the transportation efficiency of the crystallization shaft can be greatly improved, and the whole process of high-purity aluminum crystallization, melting, and melting casting preparation can be realized. Continuous operation can significantly improve the controllability and efficiency rhythm of the process.

[0109] Several groups of examples are provided below to describe the continuous crystallization purification method of high-purity aluminum of the embodiment in detail as follows:

[0110] Example 1:

[0111] Step S1, pour the high-temperature aluminum liquid (i.e. aluminum-containing liquid 15) with a purity of 4N6 and a weight of 400±10Kg into the crystallization crucible 12 which has been sprayed with alumina and preheated to 660-670℃, and start the crucible heater 13 to control the aluminum liquid temperature at 20±1℃ above the liquidus of the aluminum liquid.

[0112] Step S2, spray BN with a thickness of about 5μm on the surface of the crystallization shaft 52, and bake at 370℃ for 10min, then use the rotating lifting device 3 to hoist the crystallization device 4 to the top of the crystallization furnace, and lower it at a speed of 10mm / s, insert the crystallization shaft 52 of the crystallization device 4 into the aluminum liquid until the distance between the lower end surface of the crystallization shaft 52 and the bottom of the crystallization crucible 12 is 250mm.

[0113] Step S3, the argon gas is introduced into the crystallization crucible 12, the pressure of the argon gas is 0.15 MPa, the flow rate is 7 L / min, the argon gas is introduced in the mode of opening for 1 min and closing for 1 min in intermittent circulation, the crystallization rotating motor 10-1 is started, and is operated for 60 min, during which the rotating speed is uniformly reduced from 370 r / min to 210 r / min, at the same time, the electromagnetic stirrer 14 is started, the power frequency is selected as 25 Hz, the current intensity is selected as 750 A, the electromagnetic force generated by the electromagnetic stirrer 14 is used to drive the aluminum liquid to move in the circumferential direction, the moving direction is opposite to the rotating direction of the crystallization shaft 52, the first heater 26 is started, the heating temperature is set as 10±1 ℃ above the liquidus of the aluminum liquid, the vortex refrigerator 17 is started to generate cooling gas, the cooling air passes through the first air inlet channel 19-1 and the second air inlet channel 36 in sequence, reaches the mandrel 30, then enters the cooling channel 37 through the loop through hole 31, and spirally rises along the heat dissipation fins 32, at the same time, part of the radiant heat generated by the shaft sleeve 29 is taken away, the crystallization ingot 16 is obtained on the shaft sleeve 29, finally, the cooling air is discharged through the air outlet channel 35, wherein the parameters of the vortex refrigerator 17 are set as: the gas temperature is 25±1 ℃, the gas flow rate is 2100 L / min, and the refrigeration time is 60 min.

[0114] Step S4, after the crystallization is completed, the electromagnetic stirrer 14, the crystallization rotating motor 10-1 and the first heater 26 are sequentially closed, the crystallization shaft 52 together with the crystallization ingot 16 is lifted out of the crystallization crucible 12 by the rotating lifting device 4 and is transferred into the aluminum melting furnace 38, then the vortex refrigerator 17 is closed, then the first radiation heater 48, the first immersion heater 44 and the second immersion heater 49 are sequentially heated to 190±1 ℃ above the liquidus of the aluminum liquid, so that the crystallization ingot 16 is heated and melted, at the same time, by controlling the magnetic pump 53, the second stopper rod 46 and the first stopper rod 45, the high-temperature aluminum liquid above one third of the hearth of the static furnace 39 is first pumped into the aluminum melting furnace through the second channel 56, then nearly equal amount of low-temperature aluminum liquid is returned from the aluminum melting furnace 38 to the static furnace 39 through the first channel 55, until the crystallization ingot 16 is completely melted, then the temperatures of the first radiation heater 48, the first immersion heater 44 and the second immersion heater 49 are sequentially adjusted to 20±1 ℃ above the liquidus for heat preservation, when the aluminum liquid in the static furnace 39 reaches a certain capacity (such as meeting the casting requirements), the third stopper rod 47 is opened, the aluminum liquid in the static furnace 39 flows into the casting system from the aluminum outlet 54 to be cast into an ingot.

[0115] Step S5, according to the weight of the previous crystallization ingot, the same amount of aluminum liquid is added into the crystallization crucible, the next crystallization is repeated by steps S1-S4, the number of repetitions can be selected according to actual needs, so as to obtain crystallization ingots with different purity levels and weights (as shown in Table 1).

[0116] Table 1: Crystallization results of aluminum liquid with purity of 4N6

[0117] Number of crystallizations Crystallization ingot weight / Kg Crystallization ingot purity / % Yield / % 1 80.6 99.99920％ 20.1％ 2 81.3 99.99907％ 28.6％ 3 81.5 99.99895％ 37.5％ 4 80.1 99.99883％ 44.4％ 5 82.1 99.99872％ 50.1％ 6 81.7 99.99861％ 54.5％

[0118] Example 2

[0119] The same process steps and process parameters as in Example 1 are used, except that in Example 2, the high-temperature aluminum liquid with a purity of 4N8 and a weight of 400±10 Kg is poured into the crystallization crucible for crystallization purification, and the results are shown in Table 2.

[0120] Table 2 Crystallization results of aluminum liquid with a purity of 4N8

[0121] Number of crystallizations Crystallization ingot weight / Kg Crystallization ingot purity / % Yield / % 1 80.2 99.99960％ 20.0％ 2 80.3 99.99953％ 27.9％ 3 80.7 99.99947％ 36.6％ 4 81.4 99.99941％ 44.7％ 5 81.8 99.99935％ 50.0％ 6 80.9 99.99930％ 54.2％

[0122] Example 3

[0123] The same process steps and process parameters as in Example 1 are used, except that in Example 3, the high-temperature aluminum liquid with a purity of 5N and a weight of 400±10 Kg is poured into the crystallization crucible for crystallization purification, and the results are shown in Table 3.

[0124] Table 3 Crystallization results of aluminum liquid with a purity of 5N

[0125] Number of crystallizations Crystallization ingot weight / Kg Crystallization ingot purity / % Yield / % 1 81.5 99.99975％ 20.4％ 2 81.9 99.99971％ 28.2％ 3 82.2 99.99968％ 37.3％ 4 81.3 99.99964％ 45.1％ 5 82.7 99.99961％ 50.8％ 6 81.5 99.99958％ 54.7％

[0126] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A continuous purification method of high-purity aluminum by crystallization, comprising: S1.pouring an aluminum-containing liquid into a crystallization crucible in a crystallization furnace and controlling the temperature of the aluminum-containing liquid to be above the liquidus of the aluminum liquid; S2.transferring the crystallization device to above the crystallization furnace by a rotary lifting device, slowly inserting a crystallization shaft in the crystallization device into the aluminum-containing liquid, the speed of the crystallization shaft inserted into the aluminum-containing liquid is ≤10mm / s, and the distance between the lower end surface of the crystallization shaft and the bottom of the crystallization crucible is 250±20mm; S3.introducing a protective gas into the crystallization crucible, stirring the aluminum-containing liquid by an electromagnetic stirrer, rotating the crystallization shaft in the opposite direction of the stirring direction of the electromagnetic stirrer, and introducing a cooling gas into the crystallization shaft by a vortex refrigerator, the temperature of the cooling gas is 25-45℃, and the flow rate is 1500-2500L / min, starting crystallization, and obtaining a crystallization ingot; S4.after the crystallization is completed, the crystallization ingot is taken out from the crystallization crucible with the crystallization shaft by the rotary lifting device, transferred to a double-chamber furnace, melted, and cast into an ingot to obtain high-purity aluminum; wherein the crystallization furnace (1) comprises a first furnace body, a first furnace cover (25), and an electromagnetic stirrer (14), the first furnace cover is connected to a support beam (23) located directly above the first furnace cover through a first lifting rod (24), so that the first furnace cover is suspended on the first furnace body, the support beam is provided with a lifting hole (23-1), a second lifting rod (11) is arranged in the lifting hole, the support beam is connected to a cantilever of the rotary lifting device through the second lifting rod, the electromagnetic stirrer is arranged at the bottom of the first furnace body and used for stirring the aluminum-containing liquid; the rotary lifting device (3) comprises a base (5), a vertical column (8), a vertical column rotating mechanism (6), a vertical column rotating motor (6-1), a cantilever (9), a cantilever lifting mechanism (7), and a cantilever lifting motor (7-1), the bottom end of the vertical column is arranged on the base, one end of the cantilever is connected to the vertical column through the cantilever lifting mechanism, the cantilever lifting motor is arranged at the top end of the vertical column and connected to the cantilever lifting mechanism, the crystallization device is arranged on the other end of the cantilever, the vertical column rotating mechanism is connected to the vertical column, the vertical column rotating motor is connected to the vertical column rotating mechanism, the vertical column rotating mechanism is driven by the vertical column rotating motor to rotate the vertical column, so as to rotate the crystallization device to the position of the crystallization furnace or the double-chamber furnace; the crystallization device (4) comprises a crystallization shaft (52), a quick-mounting clamping mechanism (22), and a crystallization rotating mechanism (10), the top end of the crystallization shaft is connected to the crystallization rotating mechanism through the quick-mounting clamping mechanism, the crystallization rotating mechanism is arranged on the cantilever of the rotary lifting device, the bottom end of the crystallization shaft extends into the first furnace body through the first furnace cover, the crystallization shaft is driven to rotate by the crystallization rotating mechanism, the rotating direction of the crystallization shaft is opposite to the stirring direction of the electromagnetic stirrer, and the rotating speed of the crystallization shaft is synchronous with the stirring speed of the electromagnetic stirrer, the rotating speed of the crystallization shaft is 200-400r / min.

2. The continuous purification method of high purity aluminum by fractional crystallization according to claim 1, characterized by, further comprising: S5.melting the crystallization ingot and repeating steps S1-S4 until high-purity aluminum of a required purity grade is obtained.

3. The continuous purification method of high purity aluminum by crystallization deposition according to claim 1 or 2, characterized by, the temperature of the aluminum-containing liquid in step S1 is controlled to be 20±3℃ above the liquidus of the aluminum liquid.

4. The continuous purification method of high purity aluminum by crystallization deposition according to claim 1 or 2, characterized by, Before pouring the aluminum-containing liquid into the crystallization crucible, further comprising: Spraying alumina in the crystallization crucible and preheating.

5. The high purity aluminum continuous crystallization purification method according to claim 1 or 2, characterized by, Before slowly inserting the crystallization shaft into the aluminum-containing liquid, further comprising: Spraying BN on the surface of the crystallization shaft and baking at a temperature of 250-400°C.

6. The high purity aluminum continuous crystallization purification method according to claim 1 or 2, characterized by, The crystallization shaft has a conical shape with a taper of 0.5-5°.

7. The continuous purification method of high purity aluminum by crystallization deposition according to claim 1 or 2, characterized by, The protective gas is nitrogen or argon, and the protective gas is intermittently circulated.

8. The high purity aluminum continuous crystallization purification method according to claim 1 or 2, characterized by, The step S3 further comprises: Heating and holding the protective gas in the crystallization crucible.

9. The continuous purification method of high purity aluminum by fractional crystallization according to claim 8, characterized by, The heating temperature of the protective gas is 10±3°C above the liquidus of the aluminum liquid.

10. The high purity aluminum continuous crystallization purification method according to claim 1 or 2, characterized by, The step S4 takes out the crystallization ingot from the crystallization crucible with the crystallization shaft, melts, and casts into an ingot to obtain high-purity aluminum, specifically comprising: Transporting the crystallization ingot with the crystallization shaft to a melting furnace for melting to obtain an aluminum liquid; Passing the aluminum liquid into a holding furnace for holding until the aluminum liquid in the holding furnace reaches the casting requirements, and then flowing the aluminum liquid into a casting system for casting into an ingot.

11. The continuous purification method of high purity aluminum by fractional crystallization according to claim 10, characterized by, The step S4 further specifically comprises: Maintaining the inventory of the aluminum liquid in the melting furnace to be not less than half of the height of the hearth of the melting furnace, and maintaining the temperature of the aluminum liquid in the melting furnace to be 20±3°C above the liquidus of the aluminum liquid; Maintaining the inventory of the aluminum liquid in the holding furnace to be not less than one-third of the height of the hearth of the holding furnace, and maintaining the temperature of the aluminum liquid in the holding furnace to be 60±3°C above the liquidus of the aluminum liquid.

12. The continuous purification method of high purity aluminum by fractional crystallization according to claim 11, characterized by, When transporting the crystallization ingot with the crystallization shaft to the melting furnace for melting, pumping the inventory of the aluminum liquid in the holding furnace back to the melting furnace to accelerate the melting of the crystallization ingot.

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