Crystallization device, crystallization method and use thereof

Abstract

The invention relates to the technical field of crystallization, and provides a crystallization device, a crystallization method and application thereof, and the crystallization device comprises a crystallization furnace, an atmosphere heating mechanism, a temperature detection mechanism and a controller. The temperature of the metal melt in the crystallization furnace and the temperature of the atmosphere in the crystallization furnace are detected, the atmosphere in the crystallization furnace is heated through the atmosphere heating mechanism, the temperature difference between the atmosphere temperature and the temperature of the metal melt is within the range of 5 DEG C all the time along with reduction of the temperature of the metal melt in the crystallization process, and therefore the temperature difference between the atmosphere temperature and the temperature of the metal melt is within the range of 5 DEG C; and the consistency of the atmosphere temperature and the metal melt temperature in the crystallization furnace is ensured, and the forming uniformity and the component consistency of crystallization ingots are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of crystallization technology, and in particular to a crystallization device, a crystallization method and uses thereof. Background Art

[0002] Crystallization purification of high-purity aluminum is a process for preparing high-purity aluminum by utilizing the segregation characteristics of impurity elements during the transformation of aluminum liquid from liquid to solid. The so-called segregation refers to the phenomenon that the solid alloy or metal composition is different from the original liquid composition during the solidification process of the alloy or pure metal. Generally speaking, the content of trace impurity elements in the solidified crystal is much lower than that of the original aluminum liquid. However, during the crystallization process, due to different crystallization speeds, the quality of the formed crystallization ingots is uneven and the consistency of the composition is reduced. Summary of the invention

[0003] Based on this, an embodiment of the present application provides a crystallization device, a crystallization method and uses thereof with stable crystallization quality and good consistency of formed crystallization ingots.

[0004] In a first aspect, the present application provides a crystallization device, the crystallization device comprising:

[0005] A crystallization furnace comprises a furnace body, a furnace cover and a crystallization axis. The furnace body is used to melt metal and accommodate the molten metal. The furnace cover is used to cover the furnace body. The crystallization axis passes through the furnace cover and is arranged in the furnace body. The crystallization axis is used for crystallization and purification.

[0006] An atmosphere heating mechanism is provided on the crystallization furnace and is used for heating the atmosphere between the furnace cover and the molten metal.

[0007] The temperature detection mechanism includes a molten metal temperature detector and an atmosphere temperature detector; the molten metal temperature detector is arranged on the side wall of the furnace body and is used to detect the temperature of the molten metal in the furnace body; the atmosphere temperature detector is arranged in the furnace body and is used to detect the temperature of the atmosphere between the molten metal and the furnace cover.

[0008] A controller is separately and independently electrically connected to the atmosphere heating mechanism, the molten metal temperature detector and the atmosphere temperature detector, and is used to receive detection signals from the atmosphere heating mechanism and the molten metal temperature detector, and feedback control the heating temperature of the atmosphere heating mechanism so that the difference between the temperature of the molten metal and the temperature of the atmosphere is less than 5°C.

[0009] In some embodiments, the atmosphere heating mechanism includes a first heater disposed on a side of the furnace cover close to the molten metal.

[0010] Optionally, the first heater includes a plurality of first heating elements arranged at intervals.

[0011] In some embodiments, the atmosphere heating mechanism includes a second heater disposed on the furnace body, wherein the second heater is disposed on an outer surface of the furnace body and is located in a region between the furnace cover and a liquid surface of the molten metal.

[0012] Optionally, the second heater includes a plurality of second heating elements arranged at intervals along the circumference of the furnace body.

[0013] In some embodiments, the atmosphere temperature detector includes a plurality of first temperature sensors spaced apart along the circumferential direction of the inner wall of the furnace body.

[0014] Optionally, a vertical distance between the first temperature sensor and the plane where the furnace opening is located is 10 mm to 50 mm.

[0015] In some embodiments, the molten metal temperature detector further includes a second temperature sensor disposed on the furnace body.

[0016] Optionally, a temperature measuring hole is opened on the side wall of the furnace body along the height direction, and the second temperature sensor is arranged in the temperature measuring hole.

[0017] Optionally, the diameter of the temperature measuring hole is 0.1 to 0.5 times the thickness of the furnace wall.

[0018] Optionally, the depth of the temperature measuring hole is 0.5 to 0.9 times the height of the furnace body.

[0019] In a second aspect, the present application provides a crystallization method, wherein the crystallization method uses the crystallization device as described in the first aspect, comprising:

[0020] Adding metal into the furnace body, heating and melting to form a molten metal, and keeping the molten metal warm;

[0021] The molten metal temperature detector is used to detect the temperature of the molten metal, and the atmosphere temperature detector is used to detect the temperature of the atmosphere between the liquid surface of the molten metal in the furnace body and the furnace cover; and the atmosphere heating mechanism is started at the same time, so that the difference between the temperature of the molten metal and the temperature of the atmosphere is less than 5°C;

[0022] When the temperature difference between the metal melt and the atmosphere is less than 5° C., inserting the crystallization axis into the metal melt, and simultaneously introducing a cooling medium into the crystallization axis for crystallization purification, so that a metal layer is crystallized on the surface of the crystallization axis;

[0023] When the temperature of the metal melt drops to the termination temperature, the crystallization axis after crystallization and purification is taken out from the furnace body to obtain a crystallization ingot.

[0024] In some embodiments, the difference between the temperature of the metal melt and the temperature of the atmosphere is less than 3°C.

[0025] In some embodiments, the difference between the insulation temperature and the liquidus temperature of the metal melt is 30°C to 60°C.

[0026] In some embodiments, the difference between the termination temperature and the liquidus temperature of the metal melt is 0°C to 10°C.

[0027] In some embodiments, the difference between the heating temperature of the atmosphere heating mechanism and the temperature of the metal melt is -1°C to 1°C.

[0028] In a third aspect, the present application provides a use of the crystallization device as described in the first aspect, wherein the crystallization device is used for crystallizing and purifying aluminum.

[0029] Compared with the traditional technology, this application has at least the following beneficial effects:

[0030] The present application detects the temperature of the molten metal in the crystallization furnace and the temperature of the atmosphere in the crystallization furnace, and uses an atmosphere heating mechanism to heat the atmosphere in the crystallization furnace. As the temperature of the molten metal decreases during the crystallization process, the temperature difference between the atmosphere temperature and the molten metal is always within the range of 5°C, thereby ensuring the consistency of the atmosphere temperature and the molten metal temperature in the crystallization furnace, and significantly improving the uniformity of crystallization ingot formation and the consistency of composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of a crystallization device provided in one embodiment of the present application;

[0032] Figure 2 This is a schematic structural diagram of a first heater provided in one embodiment of the present application;

[0033] Figure 3 This is a schematic structural diagram of another first heater provided in one embodiment of the present application;

[0034] Figure 4 This is a schematic structural diagram of another first heater provided in one embodiment of the present application;

[0035] Figure 5 This is a structural schematic diagram of another first heater provided in one embodiment of the present application;

[0036] Figure 6 This is a photograph of the crystallization ingot prepared in Example 1 of the present application;

[0037] Figure 7 This is a photograph of the crystallization ingot prepared in Comparative Example 3 of the present application.

[0038] Among them, 100-crystallization furnace; 110-furnace body; 120-furnace cover; 130-crystallization axis; 200-atmosphere heating mechanism; 210-first heater; 211-first heating element; 220-second heater; 300-temperature detection mechanism; 310-metal melt temperature detector; 320-atmosphere temperature detector. DETAILED DESCRIPTION

[0039] Below in conjunction with the embodiments and examples, the present application is further described in detail. These embodiments and examples are only used to illustrate the present application and are not used to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the understanding of the disclosure of the present application more thorough and comprehensive. It should also be understood that the present application can be implemented in many different forms, and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the present application, and the equivalent form obtained also falls within the protection scope of the present application. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0041] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0042] In this application, the terms "first", "second", etc. in "the first aspect", "the second aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0043] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0044] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for a broad range of quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0045] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0046] In traditional technology, the upper end surface of the crystallization ingot formed by crystallization and purification in the crystallization furnace is prone to capping or severe edge grinding, and the axial composition of the crystallization ingot along the crystallization axis is inconsistent. This application study found that this is because the atmosphere temperature in the crystallization furnace is lower than the temperature of the molten metal, so there is an obvious temperature gradient along the axial direction of the crystallization axis, which leads to inconsistent crystal growth rates in various parts along the axial direction of the crystallization axis. The crystallization rate near the liquid surface is significantly greater than the crystallization rate of the part far from the liquid surface, which causes the crystallization ingot to have an uneven morphology and inconsistent composition.

[0047] The first aspect of the present application provides a crystallization device, such as Figure 1 As shown, the crystallization device includes a crystallization furnace 100, an atmosphere heating mechanism 200, a temperature detection mechanism 300 and a controller (not shown in the figure).

[0048] Among them, the crystallization furnace 100 includes a furnace body 110, a furnace cover 120 and a crystallization axis 130. The furnace body 110 is used to melt metal and accommodate the molten metal. The furnace cover 120 is used to cover the furnace body 110. The crystallization axis 130 passes through the furnace cover 120 and is arranged in the furnace body 110. The crystallization axis 130 is used for crystallization and purification.

[0049] The atmosphere heating mechanism 200 is disposed on the crystallization furnace 100 and is used to heat the atmosphere between the furnace cover 120 and the molten metal. The temperature detection mechanism 300 includes a molten metal temperature detector 310 and an atmosphere temperature detector 320; the molten metal temperature detector 310 is disposed on the side wall of the furnace body 110 and is used to detect the temperature of the molten metal in the furnace body 110; the atmosphere temperature detector 320 is disposed in the furnace body 110 and is used to detect the temperature of the atmosphere between the molten metal and the furnace cover 120.

[0050] The controller is independently electrically connected to the atmosphere heating mechanism 200, the metal melt temperature detector 310 and the atmosphere temperature detector 320, and is used to receive detection signals from the atmosphere heating mechanism 200 and the metal melt temperature detector 310, and feedback control the heating temperature of the atmosphere heating mechanism 200 so that the difference between the temperature of the metal melt and the temperature of the atmosphere is less than 5°C.

[0051] The present application detects the temperature of the molten metal in the crystallization furnace 100 and the temperature of the atmosphere in the crystallization furnace 100, and uses the atmosphere heating mechanism 200 to heat the atmosphere in the crystallization furnace 100. As the temperature of the molten metal decreases during the crystallization process, the temperature difference between the atmosphere temperature and the molten metal is always within the range of 5°C, thereby ensuring the consistency of the atmosphere temperature and the molten metal temperature in the crystallization furnace 100, and significantly improving the uniformity of crystallization ingot formation and the consistency of composition.

[0052] In some embodiments, the atmosphere heating mechanism 200 includes a first heater 210 disposed on a side of the furnace cover 120 close to the molten metal.

[0053] Alternatively, if Figure 2 , Figure 3 and Figure 4 As shown, the first heater 210 includes a plurality of first heating elements 211 arranged at intervals. Further optionally, the first heating elements 211 may be arranged at intervals along the circumference of the furnace cover 120, and the first heating elements 211 may be rectangular, trapezoidal or fan-shaped. Figure 5 As shown, the first heating elements 211 are arranged at intervals in a direction away from the crystallization axis 130 , for example, they may be a plurality of annular first heating elements 211 spaced apart and arranged around the crystallization axis 130 .

[0054] The present application sets a heater on the furnace cover 120 to heat the atmosphere in the furnace body 110, effectively avoiding changes in the temperature of the atmosphere at the connection point between the crystallization axis 130 and the furnace cover 120. Furthermore, the present application sets a plurality of first heating elements 211 along the circumference of the furnace cover 120, which can effectively ensure the stability of the temperature of the atmosphere in the furnace body 110, effectively avoid the formation of a temperature gradient during the crystallization process, and improve the morphological uniformity and composition consistency of the crystallization ingot.

[0055] In some embodiments, Figure 1 As shown, the atmosphere heating mechanism 200 includes a second heater 220 disposed on the furnace body 110 . The second heater 220 is disposed on the outer surface of the furnace body 110 and is located in a region between the furnace cover 120 and the liquid surface of the molten metal.

[0056] Optionally, the second heater 220 includes a plurality of second heating elements spaced apart from each other along the circumference of the furnace body 110 .

[0057] The present application utilizes the second heater 220 disposed on the furnace body 110 to heat the atmosphere in the furnace body 110 , thereby improving the temperature uniformity of the atmosphere and thereby ensuring the morphology uniformity and composition consistency of the crystallized ingot.

[0058] In some embodiments, the atmosphere temperature detector 320 includes a plurality of first temperature sensors arranged at intervals along the inner wall of the furnace body 110. The present application detects the atmosphere temperature by setting a plurality of temperature sensors to ensure the accuracy of the detected temperature.

[0059] Optionally, the vertical distance between the first temperature sensor and the plane where the furnace body 110 opening is located is 10 mm to 50 mm, for example, it can be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm or 50 mm. It can be 20 mm to 40 mm. Since the atmosphere near the furnace cover 120 is prone to cooling due to the gap between the crystallization axis 130 and the furnace cover 120, the present application selects the position of the first temperature sensor as above to further ensure the accuracy of the atmosphere temperature detection.

[0060] In some embodiments, Figure 1 As shown, the molten metal temperature detector 310 further includes a second temperature sensor disposed on the furnace body 110 .

[0061] Optionally, a temperature measuring hole is provided on the side wall of the furnace body 110 along the height direction, and the second temperature sensor is arranged in the temperature measuring hole. Further optionally, the temperature measuring hole is provided on the side wall of the furnace body 110, and can be provided along the height direction of the side wall, and the provided position can be close to the middle position in the thickness direction of the side wall.

[0062] Optionally, the diameter of the temperature measuring hole is 0.1 to 0.5 times the wall thickness of the furnace body 110 , for example, it may be 0.1, 0.2, 0.3, 0.4 or 0.5 times.

[0063] Optionally, the depth of the temperature measuring hole is 0.5 to 0.9 times the height of the furnace body 110 , for example, it may be 0.5, 0.6, 0.7, 0.8 or 0.9 times.

[0064] The present application selects the position of the second temperature sensor as described above to ensure the accuracy of detecting the temperature of the molten metal in the furnace body 110, thereby ensuring the temperature consistency during the crystallization process.

[0065] In some embodiments, the furnace body 110 may be a crucible. Further, a heater for heating the molten metal is disposed in the crystallization furnace 100 .

[0066] It is understandable that cooling liquid may be injected into the crystallization axis 130 to achieve crystallization of the metal melt. Further, the crystallization axis 130 may also be provided with a rotator to achieve the rotation of the crystallization axis 130.

[0067] The second aspect of the present application provides a crystallization method, wherein the crystallization method uses the crystallization device as described in the first aspect, comprising:

[0068] Adding metal into the furnace body 110 to heat and melt to form a metal melt, and keeping the metal melt warm;

[0069] The molten metal temperature detector 310 is used to detect the temperature of the molten metal, and the atmosphere temperature detector 320 is used to detect the temperature of the atmosphere between the liquid surface of the molten metal in the furnace body 110 and the furnace cover 120; and the atmosphere heating mechanism 200 is started at the same time, so that the difference between the temperature of the molten metal and the temperature of the atmosphere is less than 5°C;

[0070] When the temperature difference between the metal melt and the atmosphere is less than 5° C., the crystallization axis 130 is inserted into the metal melt, and a cooling medium is introduced into the crystallization axis for crystallization purification, so that a metal layer is crystallized on the surface of the crystallization axis 130;

[0071] When the temperature of the metal melt drops to the termination temperature, the crystallization shaft 130 after crystallization and purification is taken out from the furnace body 110 to obtain a crystallization ingot.

[0072] The present application detects the atmosphere temperature in the crystallization furnace 100, and maintains the temperature difference between the metal melt temperature and the atmosphere temperature within 5°C during the crystallization process through the atmosphere heating mechanism 200, thereby ensuring the temperature uniformity during the crystallization process, and thus the crystallization ingot formed has a uniform morphology and good composition consistency. In addition, during the crystallization process of the present application, the crystallization temperature gradually decreases, that is, the atmosphere temperature also decreases synchronously with the temperature of the metal melt. Compared with the crystallization temperature remaining unchanged, the actual recovery rate of the crystallization ingot, that is, the yield rate, can be significantly improved. The yield rate = crystallization ingot weight / aluminum melt weight.

[0073] In some embodiments, the crystallization shaft 130 may rotate during the crystallization process to improve the diffusion of impurity elements and the purity of the crystallized ingot. Optionally, the rotation speed of the crystallization shaft 130 is 150 rpm to 300 rpm.

[0074] In some embodiments, the difference between the temperature of the metal melt and the temperature of the atmosphere is less than 3°C, for example, it can be 0.2°C, 0.4°C, 0.6°C, 0.8°C, 1.0°C, 1.2°C, 1.4°C, 1.6°C, 1.8°C, 2.0°C, 2.2°C, 2.4°C, 2.6°C, 2.8°C or 3.0°C. Optionally, the difference between the temperature of the metal melt and the temperature of the atmosphere is less than 1°C. The present application selects the difference between the temperature of the metal melt and the temperature of the atmosphere as above, that is, reduces the temperature difference between the atmosphere and the metal melt, thereby ensuring the temperature uniformity during the crystallization process. If the temperature difference between the atmosphere and the metal melt is relatively large, it will cause the temperature of the metal melt near the liquid surface to be lower than the temperature below it, so that the crystallization axis immersed in the metal melt forms a temperature gradient from the liquid surface to the bottom, that is, the crystallization speed near the liquid surface is fast, and the crystallization speed near the bottom is slow, which leads to the formation of the crystallization ingot morphology is inverted cone, and the crystallization ingot has a problem of poor purity consistency along the axial direction of the crystallization axis.

[0075] In some embodiments, the difference between the insulation temperature and the liquidus temperature of the molten metal is 30°C to 60°C, for example, it can be 30°C, 33°C, 36°C, 39°C, 42°C, 45°C, 48°C, 51°C, 54°C, 57°C or 60°C. It can be understood that the liquidus temperature refers to the highest temperature at which the material begins to change from liquid to solid. The insulation temperature selected in the present application as above is also the temperature at which crystallization starts, which on the one hand increases the diffusion rate of impurity elements during the crystallization process. On the other hand, it cooperates with the cooler in the crystallization shaft to increase the supercooling during the crystallization process, increase the driving force for the diffusion of impurity elements, and cooperate to improve the crystallization purification effect.

[0076] In some embodiments, the insulation time is 5 min to 10 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0077] In some embodiments, the difference between the termination temperature and the liquidus temperature of the molten metal is 0°C to 10°C, for example, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C. The termination temperature of the crystallization process selected in the present application as above not only improves the actual yield of the crystallization ingot, but also improves the diffusion capacity of the impurity elements, thereby improving the crystallization purification effect of the crystallization ingot compared to the unchanged crystallization temperature.

[0078] Optionally, the cooling rate during the crystallization process is 0.1°C / min to 0.5°C / min, for example, it can be 0.10°C / min, 0.15°C / min, 0.20°C / min, 0.25°C / min, 0.30°C / min, 0.35°C / min, 0.40°C / min, 0.45°C / min or 0.50°C / min.

[0079] In some embodiments, the difference between the heating temperature of the atmosphere heating mechanism 200 and the temperature of the metal melt is -1°C to 1°C. The heating temperature of the atmosphere heating mechanism 200 of the present application is close to the temperature of the metal melt, thereby avoiding fluctuations in the atmosphere temperature caused by excessively high or low heating temperatures, thereby affecting the crystallization stability.

[0080] Exemplarily, the above-mentioned crystallization method is provided, comprising the following steps:

[0081] Add metal into the furnace body 110 and heat and melt to form a metal melt, and keep the metal melt warm at a temperature of 30° C. to 60° C. above the liquidus temperature of the metal melt for 5 min to 10 min;

[0082] The molten metal temperature detector 310 is used to detect the temperature of the molten metal, and the atmosphere temperature detector 320 is used to detect the temperature of the atmosphere between the liquid surface of the molten metal in the furnace body 110 and the furnace cover 120; and the atmosphere heating mechanism 200 is started at the same time, so that the difference between the temperature of the molten metal and the temperature of the atmosphere is less than 5°C;

[0083] When the temperature difference between the metal melt and the atmosphere is less than 5° C., the crystallization shaft 130 is inserted into the metal melt, and a cooling medium is introduced into the crystallization shaft for crystallization purification, and the crystallization shaft 130 starts to rotate, and a metal layer is crystallized on the surface of the crystallization shaft 130;

[0084] When the temperature of the metal melt drops to the termination temperature, the difference between the termination temperature and the liquidus temperature is 0° C. to 10° C., and the crystallization axis 130 after crystallization and purification is taken out from the furnace body 110 to obtain a crystallization ingot.

[0085] A third aspect of the present application provides a use of the crystallization device as described in the first aspect, wherein the crystallization device is used for crystallizing and purifying aluminum.

[0086] The embodiments of the present application will be described in detail below in conjunction with examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are preferably referred to the guidance provided in the present application, and can also be based on the experimental manual or normal conditions in this area, can also be based on the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0087] Example 1

[0088] This embodiment adopts Figure 1 The crystallization device shown in the figure, wherein the atmosphere heating mechanism 200 includes four first heating elements 211 arranged axially at intervals on the furnace cover 120, and the first heating elements 211 are fan-shaped; and also includes four second heating elements arranged circumferentially at intervals along the furnace body 110. The atmosphere temperature detector 320 includes four first temperature sensors arranged axially at intervals along the inner wall of the furnace body 110, and the vertical distance between the first temperature sensor and the plane where the furnace body 110 opening is located is 30mm. The metal melt temperature detector 310 is set in the temperature measuring hole, the depth of the temperature measuring hole is 0.6 times the height of the furnace body 110, the diameter is 0.3 times the wall thickness of the furnace body 110, and the opening position is the middle position of the furnace body 110 wall along the thickness direction.

[0089] This embodiment also provides a method for crystallizing and purifying aluminum liquid using the above-mentioned crystallization device, comprising the following steps:

[0090] Aluminum raw materials with a purity of 5N (mass purity of 99.999%) are added into the furnace body 110 of the crystallization furnace 100, and the aluminum raw materials are heated to melt at 45°C above the liquidus temperature (i.e., 705°C, the liquidus temperature of the aluminum raw materials is 660°C) to obtain aluminum liquid, and the temperature is kept for 8 minutes;

[0091] Detect the atmosphere temperature and the aluminum liquid temperature in the furnace body 110, and start the atmosphere heating mechanism 200 to heat the atmosphere in the furnace body 110. The heating temperature of the atmosphere heating mechanism 200 is the aluminum liquid temperature + 1°C (i.e. 706°C), so that the temperature difference between the aluminum liquid temperature in the furnace body 110 and the atmosphere temperature is less than 3°C;

[0092] When the temperature difference between the aluminum liquid temperature and the atmosphere temperature in the furnace body 110 is less than 3°C, the crystallization shaft 130 is inserted into the aluminum liquid, and a cooling medium is introduced into the crystallization shaft 130, and the crystallization shaft 130 starts to rotate for crystallization purification, wherein the cooling medium is introduced at a flow rate of 65L / min~80L / min, the introduction temperature is 10°C~15°C, the rotation speed of the crystallization shaft 130 is 170rpm~180rpm, and the cooling rate of the aluminum liquid is 0.3°C / min~0.35°C / min;

[0093] When the temperature of the aluminum liquid drops to the liquidus temperature, the crystallization axis 130 is taken out from the aluminum liquid to obtain Figure 6 The crystallized ingot is shown.

[0094] Example 2

[0095] This embodiment provides a crystallization device, which is different from the embodiment 1 in that the atmosphere heating mechanism 200 includes four annular first heaters 210 spaced from the center of the furnace cover 120 to the periphery; and also includes four second heating elements spaced along the circumference of the furnace body 110. The vertical distance between the first temperature sensor in the atmosphere temperature detector 320 and the plane where the furnace body 110 opening is located is 10 mm. The metal melt temperature detector 310 is set in the temperature measuring hole, the depth of the temperature measuring hole is 0.9 times the height of the furnace body 110, and the diameter is 0.1 times the wall thickness of the furnace body 110.

[0096] This embodiment also provides a method for crystallizing and purifying aluminum liquid using the above-mentioned crystallization device, comprising the following steps:

[0097] Add aluminum raw material with a purity of 5N into the furnace body 110 of the crystallization furnace 100, heat the aluminum raw material to melt at 30°C above the liquidus temperature (i.e. 690°C, the liquidus temperature of the aluminum raw material is 660°C) to obtain aluminum liquid, and keep the temperature for 10 minutes;

[0098] Detect the atmosphere temperature and the aluminum liquid temperature in the furnace body 110, and start the atmosphere heating mechanism 200 to heat the atmosphere in the furnace body 110. The heating temperature of the atmosphere heating mechanism 200 is the aluminum liquid temperature, so that the temperature difference between the aluminum liquid temperature in the furnace body 110 and the atmosphere temperature is less than 2°C;

[0099] When the temperature difference between the aluminum liquid temperature and the atmosphere temperature in the furnace body 110 is less than 2°C, the crystallization shaft 130 is inserted into the aluminum liquid, and a cooling medium is introduced into the crystallization shaft 130, and the crystallization shaft 130 starts to rotate for crystallization purification, wherein the cooling medium is introduced at a flow rate of 50L / min~65L / min, the introduction temperature is 15°C~20°C, the rotation speed of the crystallization shaft 130 is 180rpm~200rpm, and the cooling rate of the aluminum liquid is 0.2°C / min~0.25°C / min;

[0100] When the temperature of the aluminum liquid drops to the liquidus temperature, the crystallization axis 130 is taken out from the aluminum liquid to obtain a crystallization ingot.

[0101] Example 3

[0102] This embodiment provides a crystallization device, which is different from the embodiment 1 in that the vertical distance between the first temperature sensor in the atmosphere temperature detector 320 and the plane where the furnace body 110 opening is located is 50 mm. The molten metal temperature detector 310 is arranged in the temperature measuring hole, the depth of the temperature measuring hole is 0.5 times the height of the furnace body 110, and the diameter is 0.5 times the wall thickness of the furnace body 110.

[0103] This embodiment also provides a method for crystallizing and purifying aluminum liquid using the above-mentioned crystallization device, comprising the following steps:

[0104] Add aluminum raw material with a purity of 5N into the furnace body 110 of the crystallization furnace 100, heat the aluminum raw material to melt at 60°C above the liquidus temperature (i.e. 720°C, the liquidus temperature of the aluminum raw material is 660°C) to obtain aluminum liquid, and keep the temperature for 5 minutes;

[0105] Detect the atmosphere temperature and the aluminum liquid temperature in the furnace body 110, and start the atmosphere heating mechanism 200 to heat the atmosphere in the furnace body 110. The heating temperature of the atmosphere heating mechanism 200 is the aluminum liquid temperature -1°C, so that the temperature difference between the aluminum liquid temperature in the furnace body 110 and the atmosphere temperature is less than 1°C;

[0106] When the temperature difference between the aluminum liquid temperature and the atmosphere temperature in the furnace body 110 is less than 1°C, the crystallization shaft 130 is inserted into the aluminum liquid, and a cooling medium is introduced into the crystallization shaft 130, and the crystallization shaft 130 starts to rotate for crystallization purification, wherein the cooling medium is introduced at a flow rate of 80L / min~100L / min, at a temperature of 5°C~10°C, at a rotation speed of 150rpm~170rpm, and at a cooling rate of the aluminum liquid of 0.35°C / min~0.5°C / min;

[0107] When the temperature of the aluminum liquid drops to the liquidus temperature, the crystallization axis 130 is taken out from the aluminum liquid to obtain a crystallization ingot.

[0108] Example 4

[0109] The aluminum liquid is crystallized and purified according to the method of Example 1, except that the insulation temperature of the aluminum liquid is 20° C. above the liquidus line.

[0110] Example 5

[0111] The aluminum liquid is crystallized and purified according to the method of Example 1, except that during the crystallization process, the temperature difference between the aluminum liquid temperature and the atmosphere temperature in the furnace body 110 is adjusted to 5° C. to 10° C.

[0112] Comparative Example 1

[0113] This comparative example provides a crystallization device and a crystallization method. Compared with Example 1, the difference is that the temperature of the aluminum liquid is kept constant during the crystallization process and is always 45° C. above the liquidus line to obtain a crystallization ingot.

[0114] Comparative Example 2

[0115] This comparative example provides a crystallization device and a crystallization method. Compared with Example 1, the difference is that during the crystallization process, the atmosphere temperature is maintained at 10±3° C. above the liquidus line of the aluminum liquid.

[0116] Comparative Example 3

[0117] This comparative example provides a crystallization device and a crystallization method. Compared with Example 1, the difference is that the crystallization device does not have an atmosphere heating mechanism 200. During the crystallization process, the temperature difference between the aluminum liquid and the atmosphere reaches 50°C, and the following is obtained: Figure 7 The crystallized ingot is shown.

[0118] The weight and composition of the crystallized ingots prepared in the above examples and comparative examples were tested, wherein the composition was tested by GDMS (glow discharge mass spectrometry), and the actual yield, purification rate and purity deviation corresponding to different examples were graded, and the statistical results are shown in Table 1.

[0119] Table 1

[0120]

[0121] Notes on indicators:

[0122] The actual yield, i.e. the actual yield of crystallized ingot = the weight of crystallized ingot / the weight of melt in the crucible. The actual yield is divided into grades: Grade A ≥ 25%; 22.5% ≤ Grade B < 25%; 20% ≤ Grade C < 22.5%; 17.5% ≤ Grade D < 20%; Grade E < 17.5%.

[0123] Purification rate, i.e., crystallization ingot purification rate = (melt impurity content - crystallization ingot impurity content) / melt impurity content. Purification rate classification: Grade A ≥ 85%; 82% ≤ Grade B < 85%; 79% ≤ Grade C < 82%; 75% ≤ Grade D < 79%; Grade E < 75%.

[0124] Purity deviation, i.e. purity deviation of crystallization ingot, refers to the purity difference between characteristic points M and N on the crystallization ingot; among them, points M and N are located 50mm away from the end and bottom of the crystallization ingot, and 10mm inward from the surface of the crystallization ingot, respectively. Purity deviation grades are divided into: Grade A ≤ 0.2ppm; 0.2ppm<Grade B ≤ 0.3ppm; 0.3ppm<Grade C ≤ 0.4ppm; 0.4ppm<Grade D ≤ 0.5ppm; Grade E>0.5ppm.

[0125] From the above table we can see that:

[0126] (1) Compared with Example 4, it can be seen that the present application controls the insulation temperature of the aluminum liquid, that is, the starting temperature of crystallization, improves the purification rate, and the purity of the crystallized ingot is more uniform.

[0127] (2) Compared with Example 5, it can be seen that the present invention controls the temperature difference between the atmosphere temperature and the aluminum liquid during the crystallization process, thereby improving the actual yield of crystallization and making the purity of the crystallized ingot more uniform.

[0128] (3) Compared with Example 1, it can be seen that in the crystallization process of the present invention, the temperature of the aluminum liquid gradually decreases, which is compared with the case where the temperature of the aluminum liquid remains unchanged during the crystallization process, thereby improving the actual recovery rate and purification rate of the crystallized ingot.

[0129] (4) Compared with Comparative Examples 2-3, Example 1 Figure 6 and Figure 7 It can be seen that the morphology of the crystallization ingot in comparative example 3 is an inverted cone, indicating that the crystallization is uneven from the end face of the crystallization axis 130 to the aluminum liquid surface. The closer to the aluminum liquid surface, the lower the temperature, and the faster the growth rate of the crystallization ingot. In Example 1 of the present application, the atmosphere temperature is regulated, and the morphology of the crystallization ingot is cylindrical, indicating that the crystallization from the end face of the crystallization axis 130 to the aluminum liquid surface tends to be uniform, and the crystallization rate of each part of the crystallization ingot is similar. The present application detects the temperature of the molten metal in the crystallization furnace 100 and the atmosphere temperature in the crystallization furnace 100, and uses the atmosphere heating mechanism 200 to heat the atmosphere in the crystallization furnace 100. As the temperature of the molten metal decreases during the crystallization process, the temperature difference between the atmosphere temperature and the molten metal is always within the range of 5°C, ensuring the consistency of the atmosphere temperature and the molten metal temperature in the crystallization furnace 100, and significantly improving the uniformity of the crystallization ingot formation and the consistency of the composition.

[0130] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0131] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A crystallization device, characterized in that: The crystallization device comprises: A crystallization furnace comprises a furnace body, a furnace cover and a crystallization shaft, wherein the furnace body is used to melt metal and contain the molten metal, the furnace cover is used to cover the furnace body, the crystallization shaft passes through the furnace cover and is arranged in the furnace body, and the crystallization shaft is used for crystallization purification; An atmosphere heating mechanism, which is disposed on the crystallization furnace and is used to heat the atmosphere between the furnace cover and the molten metal; The temperature detection mechanism comprises a molten metal temperature detector and an atmosphere temperature detector; the molten metal temperature detector is arranged on the side wall of the furnace body and is used to detect the temperature of the molten metal in the furnace body; the atmosphere temperature detector is arranged in the furnace body and is used to detect the temperature of the atmosphere between the molten metal and the furnace cover; A controller is separately and independently electrically connected to the atmosphere heating mechanism, the molten metal temperature detector and the atmosphere temperature detector, and is used to receive detection signals from the atmosphere heating mechanism and the molten metal temperature detector, and feedback control the heating temperature of the atmosphere heating mechanism so that the difference between the temperature of the molten metal and the temperature of the atmosphere is less than 5°C.

2. The crystallization device according to claim 1, characterized in that The atmosphere heating mechanism comprises a first heater arranged on a side of the furnace cover close to the metal melt; Optionally, the first heater includes a plurality of first heating elements arranged at intervals.

3. The crystallization device according to claim 1, characterized in that The atmosphere heating mechanism comprises a second heater disposed on the furnace body, wherein the second heater is disposed on the outer surface of the furnace body and is located in a region between the furnace cover and the liquid surface of the molten metal; Optionally, the second heater includes a plurality of second heating elements arranged at intervals along the circumference of the furnace body.

4. The crystallization device according to any one of claims 1 to 3, characterized in that: The atmosphere temperature detector comprises a plurality of first temperature sensors arranged at intervals along the circumferential direction of the furnace body wall; Optionally, a vertical distance between the first temperature sensor and the plane where the furnace opening is located is 10 mm to 50 mm.

5. The crystallization device according to any one of claims 1 to 3, characterized in that: The metal melt temperature detector also includes a second temperature sensor disposed on the furnace body; Optionally, a temperature measuring hole is opened on the side wall of the furnace body along the height direction, and the second temperature sensor is arranged in the temperature measuring hole; Optionally, the diameter of the temperature measuring hole is 0.1 to 0.5 times the thickness of the furnace wall; Optionally, the depth of the temperature measuring hole is 0.5 to 0.9 times the height of the furnace body.

6. A crystallization method, characterized in that: The crystallization method adopts the crystallization device according to any one of claims 1 to 5, comprising: Adding metal into the furnace body, heating and melting to form a molten metal, and keeping the molten metal warm; The molten metal temperature detector is used to detect the temperature of the molten metal, and the atmosphere temperature detector is used to detect the temperature of the atmosphere between the liquid surface of the molten metal in the furnace body and the furnace cover; and the atmosphere heating mechanism is started at the same time, so that the difference between the temperature of the molten metal and the temperature of the atmosphere is less than 5°C; When the temperature difference between the metal melt and the atmosphere is less than 5° C., inserting the crystallization axis into the metal melt, and simultaneously introducing a cooling medium into the crystallization axis for crystallization purification, so that a metal layer is crystallized on the surface of the crystallization axis; When the temperature of the metal melt drops to the termination temperature, the crystallization axis after crystallization and purification is taken out from the furnace body to obtain a crystallization ingot.

7. The crystallization method according to claim 6, characterized in that The difference between the temperature of the metal melt and the temperature of the atmosphere is less than 3°C.

8. The crystallization method according to claim 6, characterized in that The crystallization method satisfies at least one of the following conditions: (1) The difference between the insulation temperature and the liquidus temperature of the molten metal is 30°C to 60°C; (2) The difference between the termination temperature and the liquidus temperature of the metal melt is 0°C to 10°C.

9. The crystallization method according to any one of claims 6 to 8, characterized in that: The difference between the heating temperature of the atmosphere heating mechanism and the temperature of the metal melt is -1°C to 1°C.

10. Use of the crystallization device according to any one of claims 1 to 6, characterized in that: The crystallization device is used for crystallization and purification of aluminum.

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