A continuous preparation device and method for aluminum-rare earth alloy with adjustable components

Abstract

The application provides a molten salt electrolysis preparation device for aluminum-rare earth alloy, which comprises an electrolysis tank body, an insulating material inner wall arranged on the inner wall of the electrolysis tank body, no insulating material inner wall arranged on the inner wall of the lower part of the electrolysis tank body, a blocking plate arranged in the electrolysis tank body, the transverse two ends of the blocking plate being fixed on the inner wall of the electrolysis tank, and a spacing being formed between the bottom surface of the blocking plate and the bottom of the electrolysis tank body, an anode arranged in the electrolysis tank and a cathode arranged at the bottom of the electrolysis tank. The adjustable aluminum-rare earth alloy continuous preparation device and method can realize continuous addition of aluminum liquid, continuous discharge of aluminum-rare earth alloy, stable composition and adjustable rare earth content in the aluminum-rare earth alloy in a wide range.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic preparation of aluminum-rare earth alloys, and relates to a molten salt electrolytic preparation device for aluminum-rare earth alloys and a method for continuous preparation of aluminum-rare earth alloys using molten salt electrolysis. In particular, it relates to a composition-tunable continuous preparation device and method for aluminum-rare earth alloys. Background Technology

[0002] The addition of rare earth elements to aluminum can significantly improve the properties of aluminum alloys, making aluminum-rare earth alloys widely used. Currently, aluminum-rare earth alloys can be prepared using methods such as doping, thermal reduction, and molten salt electrolysis. Among these, molten salt electrolysis is highly efficient and easily automated, and has attracted considerable attention in recent years. Molten salt electrolysis mainly includes aluminum-rare earth co-deposition and methods for preparing aluminum-rare earth alloys by electrolyzing rare earth oxides with liquid aluminum cathodes. Some corresponding research schemes have been disclosed in the industry. Among them, the aluminum-rare earth co-deposition method, such as CN02153736.4, CN03153785.5, CN03146327.4, CN200410002122.0, CN200810223984.4, CN201510458938.2, CN201710773524.8, CN202111321800.X, CN201710773531.8, and CN01138655.X, etc., for preparing aluminum-rare earth alloys, is difficult to control in terms of rare earth content, and it is particularly challenging to prepare alloys with high rare earth content.

[0003] The method of preparing aluminum-rare earth alloys by electrolyzing rare earth oxides with liquid aluminum cathodes is easy to control the rare earth content in the alloy. Existing literature reports methods for preparing aluminum-rare earth alloys by electrolysis with liquid aluminum cathodes, such as CN200620149620.2, CN201210236998.6, and CN201521067036.8. However, current methods for preparing aluminum-rare earth alloys by electrolysis with liquid aluminum cathodes only allow for intermittent addition of molten aluminum. After electrolysis for a certain period (i.e., reaching the target rare earth content), the aluminum-rare earth alloy is discharged. In actual production, if all the aluminum-rare earth alloy is discharged and then molten aluminum is added again, it will cause large heat fluctuations in the electrolytic cell, disrupting the original thermal equilibrium and resulting in significant temperature fluctuations, which is detrimental to the stable operation of the electrolytic cell. Therefore, only a portion of the aluminum-rare earth alloy can be discharged, and then some molten aluminum can be added, which greatly reduces production efficiency.

[0004] Therefore, finding a more suitable method to achieve continuous preparation of rare earth oxides by electrolysis of liquid aluminum cathodes, and solving the problem that the current method for preparing aluminum-rare earth alloys by electrolysis of rare earth oxides by liquid aluminum cathodes cannot achieve continuous addition of aluminum liquid and continuous discharge of aluminum-rare earth alloys, and that the temperature of the electrolytic cell fluctuates greatly, has become one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a molten salt electrolysis preparation apparatus for aluminum-rare earth alloys and a method for continuously preparing aluminum-rare earth alloys using molten salt electrolysis, particularly a compositionally controllable continuous preparation apparatus for aluminum-rare earth alloys. The controllable continuous preparation apparatus and method for aluminum-rare earth alloys provided by the present invention can achieve continuous addition of molten aluminum and continuous discharge of the aluminum-rare earth alloy, with stable composition, and the rare earth content in the aluminum-rare earth alloy can be controlled within a wide range.

[0006] This invention provides an apparatus for the molten salt electrolytic preparation of aluminum-rare earth alloys, including an electrolytic cell body;

[0007] The inner wall of the insulating material installed on the inner wall of the electrolytic cell;

[0008] The inner wall of the lower part of the electrolytic cell body is not provided with an insulating material inner wall.

[0009] A baffle plate installed in the electrolytic cell body;

[0010] The two transverse ends of the barrier plate are fixed to the inner wall of the electrolytic cell, and there is a gap between the bottom surface of the barrier plate and the bottom of the electrolytic cell.

[0011] The anode is set inside the electrolytic cell, and the cathode is set at the bottom of the electrolytic cell.

[0012] Preferably, the electrolytic cell contains a molten electrolyte;

[0013] The anodes in the electrolytic cell may include a single anode or multiple anodes;

[0014] Liquid aluminum is disposed inside the electrolytic cell.

[0015] The molten electrolyte is a molten electrolyte with a density less than that of liquid aluminum.

[0016] In the electrolytic cell, molten electrolyte is in the upper layer and liquid aluminum is in the lower layer.

[0017] Preferably, the anode comprises a graphite anode;

[0018] When the anode in the electrolytic cell is a single anode, the single anode is immersed in molten electrolyte;

[0019] The barrier plate is located below the single anode, and there is a certain gap between the top of the barrier plate and the bottom of the single anode;

[0020] The top of the barrier plate is above the liquid surface of the liquid aluminum and is located in the molten electrolyte;

[0021] The height of the spacing is 1 / 3 to 1 / 2 of the height of the liquid metal aluminum layer.

[0022] Preferably, when there are multiple anodes in the electrolytic cell, the multiple anodes are immersed in molten electrolyte;

[0023] The plurality of anodes are separated by an insulating material plate;

[0024] The barrier plate is disposed between multiple anodes, and the insulating material plate is vertically disposed at the top of the barrier plate;

[0025] The two transverse ends of the insulating material plate are connected to the inner wall of the insulating material;

[0026] The top of the insulating material plate is higher than the liquid level of the molten electrolyte;

[0027] The top of the barrier plate is below or equal to the liquid surface of the liquid aluminum and / or above the liquid surface of the liquid aluminum.

[0028] Preferably, the molten electrolyte comprises alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides;

[0029] The molten electrolyte contains barium fluoride;

[0030] The mass content of barium fluoride is less than 15% of the total mass of the molten electrolyte;

[0031] The bottom of the inner wall of the insulating material is lower than the liquid surface of the liquid aluminum.

[0032] Preferably, the preparation apparatus further includes a cathode current collector;

[0033] The cathode current collector is disposed on the bottom surface of the electrolytic cell body;

[0034] The preparation apparatus also includes a liquid aluminum-rare earth alloy outlet;

[0035] The liquid aluminum-rare earth alloy outlet is located at the bottom of the electrolytic cell.

[0036] The insulating material includes an insulating composite material in which the outer layer is graphite and the inner layer is one or more of aluminum oxide, boron nitride, silicon carbide, silicon nitride, and silicon carbide / silicon nitride.

[0037] This invention provides a method for the continuous preparation of aluminum-rare earth alloys using molten salt electrolysis, comprising the following steps:

[0038] 1) Liquid aluminum and molten electrolyte are placed in the electrolytic cell of the molten salt electrolysis preparation device;

[0039] The density of the molten electrolyte is less than that of liquid aluminum.

[0040] 2) Turn on the molten salt electrolysis preparation device, add liquid aluminum metal into the electrolytic cell, put rare earth oxides into the electrolytic cell, and electrolyze to continuously prepare aluminum-rare earth alloys.

[0041] Preferably, the molten electrolyte comprises alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides;

[0042] The molten electrolyte contains barium fluoride;

[0043] The mass content of barium fluoride is less than 15% of the total mass of the molten electrolyte;

[0044] The electrolysis temperature is 900–1100°C.

[0045] Preferably, the liquid aluminum is added to the electrolytic cell by slowly adding it along the cell wall.

[0046] The rate at which the liquid aluminum is added is equal to the rate at which the aluminum-rare earth alloy is released.

[0047] The liquid aluminum is added to the electrolytic cell at a location far from the outlet of the liquid aluminum-rare earth alloy in the molten salt electrolysis preparation device.

[0048] During the electrolysis process, an aluminum-rare earth alloy layer is formed at the bottom of the electrolytic cell. Then, raw materials are continuously added and aluminum-rare earth alloy is continuously released, thus achieving continuous preparation.

[0049] Preferably, the method for continuous preparation of aluminum-rare earth alloys is a method for continuous preparation of aluminum-rare earth alloys with controllable composition.

[0050] The content of rare earth elements in the aluminum-rare earth alloy is controlled by adjusting the current and the aluminum addition rate.

[0051] The content of rare earth elements in the aluminum-rare earth alloy can be controlled between 1% and 20%.

[0052] The rare earth elements include one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

[0053] This invention provides an apparatus for the molten salt electrolytic preparation of aluminum-rare earth alloys, comprising an electrolytic cell body; an insulating material inner wall disposed on the inner wall of the electrolytic cell body; an inner wall without insulating material disposed on the lower part of the inner wall of the electrolytic cell body; a baffle plate disposed in the electrolytic cell body; the two transverse ends of the baffle plate are fixed to the inner wall of the electrolytic cell body, and there is a gap between the bottom surface of the baffle plate and the bottom of the electrolytic cell body; an anode disposed in the electrolytic cell body; and a cathode disposed at the bottom of the electrolytic cell body. Compared with existing technologies, the molten salt electrolysis preparation device for aluminum-rare earth alloys provided by this invention is a device for continuous preparation of aluminum-rare earth alloys with adjustable composition. It can continuously add liquid aluminum and continuously release liquid aluminum-rare earth alloy products, making the heat of the electrolysis process more balanced, the cell temperature stable, and the electrolytic cell operating smoothly. At the same time, it can control the rare earth content in the alloy. By controlling the rate of continuous addition of liquid aluminum or controlling the density of molten electrolyte, the rare earth content in the aluminum-rare earth alloy can be easily controlled to meet the production of aluminum-rare earth alloys for different applications. Moreover, it can simultaneously achieve continuous addition of aluminum liquid and control of the rare earth content in the alloy, solving the problem of reduced alloy composition caused by the dilution of the aluminum-rare earth alloy produced when continuously adding aluminum liquid in existing aluminum-rare earth alloy preparation methods.

[0054] The molten salt electrolysis preparation apparatus and method for aluminum-rare earth alloys provided by this invention can achieve continuous addition of aluminum liquid and continuous discharge of aluminum-rare earth alloys, with stable composition and the rare earth content in the aluminum-rare earth alloys can be controlled within a wide range. Attached Figure Description

[0055] Figure 1 The electrolytic cell apparatus for continuous preparation of aluminum-rare earth alloys provided in Examples 1 to 3 of this invention;

[0056] Figure 2 This is the electrolytic cell apparatus for continuous preparation of aluminum-rare earth alloys provided in Embodiment 4 of the present invention. Detailed Implementation

[0057] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention and not for limiting the claims of the present invention.

[0058] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0059] The purity of all raw materials used in this invention is not particularly limited. However, it is preferable to use materials of analytical grade or those of aluminum-rare earth alloy produced by molten salt electrolysis, which have conventional purity levels.

[0060] All raw materials of this invention are conventional in the field, and each brand name and abbreviation is clear and distinct in its relevant application. Those skilled in the art can purchase them from the market or prepare them by conventional methods based on the brand name, abbreviation and corresponding application.

[0061] All processes and equipment in this invention are abbreviated as conventional abbreviations in the field. Each abbreviation is clear and unambiguous within its relevant application area, and those skilled in the art can understand its conventional process steps and equipment structure based on the abbreviation.

[0062] This invention provides an apparatus for the molten salt electrolytic preparation of aluminum-rare earth alloys, including an electrolytic cell body;

[0063] The inner wall of the insulating material installed on the inner wall of the electrolytic cell;

[0064] The inner wall of the lower part of the electrolytic cell body is not provided with an insulating material inner wall.

[0065] A baffle plate installed in the electrolytic cell body;

[0066] The two transverse ends of the barrier plate are fixed to the inner wall of the electrolytic cell, and there is a gap between the bottom surface (longitudinal bottom surface) of the barrier plate and the bottom of the electrolytic cell.

[0067] The anode is set inside the electrolytic cell, and the cathode is set at the bottom of the electrolytic cell.

[0068] In this invention, the electrolytic cell preferably contains a molten electrolyte.

[0069] In this invention, the anode in the electrolytic cell preferably includes a single anode or multiple anodes.

[0070] In this invention, liquid aluminum is preferably disposed in the electrolytic cell.

[0071] In this invention, the molten electrolyte is preferably a molten electrolyte with a density less than that of liquid aluminum.

[0072] In this invention, within the electrolytic cell, molten electrolyte is preferably in the upper layer and liquid aluminum is in the lower layer. Specifically, this is based on the fact that the density of the selected molten electrolyte is less than that of the liquid aluminum.

[0073] In this invention, the anode preferably comprises a graphite anode.

[0074] In this invention, when the anode in the electrolytic cell is a single anode, it is preferable that the single anode is immersed in molten electrolyte.

[0075] In this invention, the barrier plate is located below the single anode, and preferably there is a certain gap between the top of the barrier plate and the bottom of the single anode, that is, the two do not contact each other and are set at a certain distance. Specifically, the top refers to the longitudinal top, preferably the top surface corresponding to the bottom surface of the barrier plate.

[0076] In this invention, the liquid surface preferably refers to the upper liquid surface of the material layer (molten electrolyte, liquid aluminum, aluminum-rare earth alloy) formed in the vertical direction.

[0077] In this invention, the top of the barrier plate is preferably above the liquid surface of the liquid aluminum metal, and preferably located in the molten electrolyte.

[0078] In this invention, the height of the spacing is preferably 1 / 3 to 1 / 2 of the height of the liquid aluminum layer. Specifically, the height of the liquid aluminum layer in this invention is the total height of the liquid cathode.

[0079] In this invention, when there are multiple anodes in the electrolytic cell, it is preferable that the multiple anodes are immersed in molten electrolyte.

[0080] In this invention, the plurality of anodes are preferably separated by an insulating material plate.

[0081] In this invention, the barrier plate is disposed between multiple anodes, and preferably the insulating material plate is disposed vertically at the top (longitudinal top) of the barrier plate.

[0082] In this invention, the two transverse ends of the insulating material plate are preferably connected to the inner wall of the insulating material.

[0083] In this invention, the top edge (longitudinal top edge) of the insulating material plate is preferably higher than the liquid surface of the molten electrolyte layer.

[0084] In this invention, the top end (longitudinal top end) of the barrier plate is preferably below or equal to the liquid surface of the liquid aluminum and / or above the liquid surface of the liquid aluminum, more preferably below or equal to the liquid surface of the liquid aluminum or above the liquid surface of the liquid aluminum, and even more preferably below the liquid surface of the liquid aluminum layer, and is located in the liquid aluminum.

[0085] In this invention, the molten electrolyte preferably includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides.

[0086] In this invention, the molten electrolyte preferably contains barium fluoride.

[0087] In this invention, the mass content of barium fluoride is preferably less than 15% of the total mass of the molten electrolyte, more preferably less than 14%, and even more preferably less than 13%.

[0088] In this invention, the bottom of the inner wall of the insulating material is preferably lower than the liquid surface of the liquid aluminum.

[0089] In this invention, the preparation apparatus preferably includes a cathode current collector.

[0090] In this invention, the cathode current collector is preferably disposed on the bottom surface of the electrolytic cell.

[0091] In this invention, when the preparation device continuously prepares liquid aluminum-rare earth alloy, the bottom layer of the preparation device is liquid aluminum-rare earth alloy, that is, a liquid aluminum-rare earth alloy layer is formed.

[0092] In this invention, the preparation apparatus preferably includes a liquid aluminum-rare earth alloy outlet.

[0093] In this invention, the liquid aluminum-rare earth alloy outlet is preferably located at the bottom of the electrolytic cell.

[0094] In this invention, the insulating material preferably comprises an insulating composite material in which the outer layer is graphite and the inner layer is one or more of alumina, boron nitride, silicon carbide, silicon nitride, and silicon carbide / silicon nitride.

[0095] In this invention, the material of the barrier plate can be the same as or different from that of the insulating material plate, but the material of the barrier plate should be an insulating material.

[0096] This invention provides a method for the continuous preparation of aluminum-rare earth alloys using molten salt electrolysis, comprising the following steps:

[0097] 1) Liquid aluminum and molten electrolyte are placed in the electrolytic cell of the molten salt electrolysis preparation device;

[0098] The density of the molten electrolyte is less than that of liquid aluminum.

[0099] 2) Turn on the molten salt electrolysis preparation device, add liquid aluminum metal into the electrolytic cell, put rare earth oxides into the electrolytic cell, and electrolyze to continuously prepare aluminum-rare earth alloys.

[0100] The present invention first places liquid aluminum and molten electrolyte in the electrolytic cell of the molten salt electrolysis preparation device; the density of the molten electrolyte is less than that of the liquid aluminum.

[0101] In this invention, the molten electrolyte preferably includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides.

[0102] In this invention, the molten electrolyte preferably contains barium fluoride.

[0103] In this invention, the mass content of barium fluoride is preferably less than 15% of the total mass of the molten electrolyte, more preferably less than 14%, and even more preferably less than 13%.

[0104] In this invention, the electrolysis temperature is preferably 900–1100°C, more preferably 940–1060°C, and even more preferably 980–1020°C.

[0105] Finally, the molten salt electrolysis preparation device is turned on, liquid aluminum is added to the electrolytic cell, rare earth oxides are placed in the electrolytic cell, and electrolysis is carried out to continuously prepare aluminum-rare earth alloys.

[0106] In this invention, the preferred method for adding the liquid aluminum metal to the electrolytic cell is to add it slowly along the cell wall.

[0107] In this invention, the rate at which the liquid aluminum is added is preferably equal to the rate at which the aluminum-rare earth alloy is released.

[0108] In this invention, the location where the liquid aluminum is added to the electrolytic cell is preferably at the far end of the liquid aluminum-rare earth alloy outlet of the molten salt electrolysis preparation device.

[0109] In this invention, during the electrolysis process, an aluminum-rare earth alloy layer is formed at the bottom of the electrolytic cell. Then, raw materials are continuously added and aluminum-rare earth alloy is continuously released, thus achieving continuous preparation.

[0110] In this invention, the method for continuous preparation of aluminum-rare earth alloys is preferably a method for continuous preparation of aluminum-rare earth alloys with controllable composition.

[0111] In this invention, the content of rare earth elements in the aluminum-rare earth alloy is preferably controlled by adjusting the current and the aluminum addition rate.

[0112] In this invention, the content of rare earth elements in the aluminum-rare earth alloy is preferably adjustable between 1% and 20%, more preferably between 5% and 16%, and even more preferably between 9% and 12%.

[0113] In this invention, the rare earth element preferably includes one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium, more preferably lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, or yttrium.

[0114] This invention aims to complete and refine the overall technical solution, better ensure the continuous preparation of aluminum-rare earth alloys via molten electrolysis, further improve the preparation stability and compositional stability of aluminum-rare earth alloys, and enhance the controllable range of rare earth content in aluminum-rare earth alloys. The preferred continuous preparation apparatus and method for aluminum-rare earth alloys with controllable composition include the following:

[0115] See Figure 1 , Figure 1 This refers to the electrolytic cell apparatus for continuous preparation of aluminum-rare earth alloys provided in Embodiments 1 to 3 of the present invention. Wherein: the left figure is the main view, and the right figure is the top view; 1-insulating composite pipe, 2-electrolytic cell body, 3-molten electrolyte, 4-valve, 5-liquid alloy outlet, 6-cathode liquid barrier plate, 7-liquid metal, 8-graphite anode, 9-cathode current collector.

[0116] See Figure 2 , Figure 2 This is the electrolytic cell apparatus for continuous preparation of aluminum-rare earth alloys provided in Embodiment 4 of the present invention. Wherein: 1-insulating composite pipe, 2-electrolytic cell body, 3-molten electrolyte, 4-valve, 5-liquid alloy outlet, 6-cathode liquid barrier plate, 7-liquid metal, 8-graphite anode, 9-cathode current collector.

[0117] The technical solution of this invention is implemented according to the following steps:

[0118] The device is as follows: a continuous preparation device for aluminum-rare earth alloy with adjustable composition, mainly including an electrolytic cell body [2], an insulating composite tube [1], a cathode liquid barrier plate [6], a graphite anode [8], a cathode current collector [9], a liquid alloy outlet [5], and a valve [4].

[0119] The method is as follows: A continuous preparation method of aluminum-rare earth alloy with adjustable composition, characterized in that the density of the molten electrolyte is less than that of the liquid aluminum, the liquid metal [7] sinks to the bottom of the electrolytic cell, and the top of it is a molten electrolyte [3] composed of alkali metal fluoride, alkaline earth metal fluoride and rare earth fluoride, wherein the content of barium fluoride is less than 15% of the total weight of the molten salt. During the electrolysis process, the anode [8] is connected to the positive terminal of the DC power supply, the cathode current collector [9] is connected to the negative terminal of the power supply, rare earth oxides are used as raw materials, and the electrolysis temperature is 900-1100℃; the cathode liquid barrier plate [6] divides the bottom liquid cathode into two parts, left and right, and the liquid aluminum is slowly added along the left side of the tank wall. Due to the density difference, the liquid aluminum sinks into the left cathode chamber. As the electrolysis proceeds, the liquid aluminum and rare earth metal form an alloy and gradually sink. It enters the right cathode chamber through the lower notch of the cathode liquid barrier plate [6] and is continuously discharged through the liquid alloy outlet [5]. The release rate of the liquid alloy can be adjusted by the valve [4], and the rare earth content in the aluminum-rare earth alloy can be controlled by the addition rate of liquid aluminum metal and the magnitude of the electrolytic current.

[0120] Specifically, the height of the liquid metal is not higher than the height of the cathode liquid barrier plate [6].

[0121] Specifically, the distance between the bottom surface of the barrier plate and the bottom of the electrolytic cell is 1 / 3 to 1 / 2 of the total height of the liquid cathode.

[0122] Specifically, the rate at which the liquid aluminum is added is equal to the rate at which the liquid alloy is released.

[0123] Specifically, the rare earth content in the aluminum-rare earth alloy is controlled by adjusting the current and the aluminum addition rate.

[0124] Specifically, the rare earth content (%) in aluminum-rare earth alloys = current (A) * current efficiency * proportionality coefficient * 100% / aluminum addition rate (g / s), where the proportionality coefficient is approximately between 0.00015 and 0.0006.

[0125] Specifically, the outer layer of the insulating composite tube [1] is graphite, and the inner layer is one of aluminum oxide, boron nitride, silicon carbide, silicon nitride, or silicon carbide combined with silicon nitride.

[0126] Specifically, the liquid alloy can also be continuously extracted using a vacuum siphon method.

[0127] Specifically, in an electrolytic cell, the melt in the electrolytic cell is divided into one or more regions by one or more insulating composite tubes [1] to form one or more cathodes and / or one or more anodes for simultaneous electrolysis.

[0128] Specifically, the rare earth elements in the prepared alloy are one or more of the following: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

[0129] Specifically, the rare earth element content in the prepared aluminum-rare earth alloy can be controlled between 1% and 20%.

[0130] The present invention provides a continuously prepared aluminum-rare earth alloy with adjustable composition, including an apparatus and method. This molten salt electrolysis apparatus for preparing aluminum-rare earth alloys is a continuously prepared apparatus with adjustable composition, capable of continuously adding liquid aluminum while simultaneously releasing liquid aluminum-rare earth alloy products. This results in a more balanced heat distribution during electrolysis, stable cell temperature, and smooth operation of the electrolytic cell. Furthermore, it allows for the control of the rare earth content in the alloy. By controlling the rate of continuous addition of liquid aluminum or the density of the molten electrolyte, the rare earth content in the aluminum-rare earth alloy can be easily controlled, meeting the production requirements of aluminum-rare earth alloys for different applications. Moreover, it simultaneously achieves continuous addition of molten aluminum and control of the rare earth content in the alloy, solving the problem of reduced alloy composition caused by the dilution of the aluminum-rare earth alloy produced during continuous addition of molten aluminum in existing aluminum-rare earth alloy preparation methods.

[0131] The molten salt electrolysis preparation apparatus and method for aluminum-rare earth alloys provided by this invention can achieve continuous addition of aluminum liquid and continuous discharge of aluminum-rare earth alloys, with stable composition and the rare earth content in the aluminum-rare earth alloys can be controlled within a wide range.

[0132] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a molten salt electrolysis preparation apparatus for aluminum-rare earth alloys and a method for continuously preparing aluminum-rare earth alloys using molten salt electrolysis. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. They are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0133] Example 1

[0134] (1) Adopt Figure 1 The device in the middle.

[0135] (2) The density of the molten electrolyte is less than that of the liquid aluminum. The liquid metal [7] sinks to the bottom of the electrolytic cell, and the molten electrolyte [3] composed of 40% LiF-60% REF3 is on top of it. During the electrolysis process, the anode [8] is connected to the positive terminal of the DC power supply, and the cathode current collector [9] is connected to the negative terminal of the power supply. Rare earth oxide is used as raw material, and the electrolysis temperature is 900℃. The cathode liquid barrier plate [6] divides the bottom liquid cathode into two parts, left and right. The liquid aluminum is added along the left side of the tank wall at a rate of 36 kg / h. Due to the density difference, the liquid aluminum sinks into the left cathode chamber. As the electrolysis proceeds, the liquid aluminum forms an alloy with the rare earth metal and gradually sinks. It enters the right cathode chamber through the lower notch of the cathode liquid barrier plate [6]. The distance between the bottom surface of the barrier plate and the bottom of the electrolytic cell is 1 / 3 to 1 / 2 of the total height of the liquid cathode. It is continuously released through the liquid alloy outlet [5] or continuously extracted by siphon. The release speed or extraction speed is equal to the addition speed of the liquid aluminum. An aluminum-rare earth alloy containing 8% rare earth can be obtained in a 10000A electrolytic cell.

[0136] Example 2

[0137] The process is basically the same as in Example 1, except that: the molten salt system is 10% LiF-40% NaF-50% AlF3, the amount of barium fluoride added is 0-10% of the total weight of the molten salt, rare earth oxide is used as raw material, and the electrolysis temperature is 1000℃; liquid metallic aluminum is added along the left side of the tank wall at a rate of 3.6-50 kg / h, and an aluminum-rare earth alloy containing 10-20% rare earth can be obtained in an electrolytic cell of 5000-20000A. The aluminum-rare earth alloy is extracted by vacuum siphon method.

[0138] Example 3

[0139] The process is basically the same as in Example 1, except that the molten salt system is 10% LiF-40% NaF-50% AlF3, barium oxide is not added, rare earth oxide is used as raw material, the electrolysis temperature is 1100℃, and an aluminum-rare earth alloy containing 15% rare earth can be obtained. The aluminum-rare earth alloy is poured out intermittently through a container placed at the bottom of the tank.

[0140] Example 4

[0141] It is basically the same as Example 1, except that: it adopts Figure 2 The electrolysis device in the middle has an electrolysis temperature of 1050℃, which can obtain an aluminum-rare earth alloy containing 5% rare earth.

[0142] Comparative Example 5

[0143] Instead of continuously adding molten aluminum, the aluminum-rare earth alloy produced is extracted after electrolysis for a certain period of time and then injected back into the molten aluminum. Due to the large molten metal temperature, the furnace temperature fluctuates greatly during operation, with a maximum fluctuation of 200°C, which is extremely detrimental to the stable operation of the electrolytic cell.

[0144] Comparative Example 6

[0145] For large-scale rare earth molten salt electrolytic cells, if not adopted Figure 2 The multi-electrode structure in the process will greatly improve the production of insulating composite tubes [1], and even existing technologies cannot produce insulating composite tubes that meet the requirements [1].

[0146] Comparative Example 7

[0147] By continuously adding molten aluminum in a traditional electrolytic cell (i.e., without aluminum molten metal), Figure 1 and Figure 2 The cathode liquid barrier [6] in the aluminum liquid added dilutes the prepared aluminum-rare earth alloy, causing the rare earth content in the released aluminum-rare earth alloy product to be lower than the target value.

[0148] The foregoing has provided a detailed description of the apparatus and method for continuous preparation of aluminum-rare earth alloys with adjustable composition, as provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including manufacturing and using any apparatus or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the textual description of the claims, or if they include equivalent structural elements that are not substantially different from the textual description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A molten salt electrolytic preparation apparatus for aluminum-rare earth alloys, characterized in that, Including the electrolytic cell body; The inner wall of the insulating material installed on the inner wall of the electrolytic cell; The inner wall of the lower part of the electrolytic cell body is not provided with an insulating material inner wall. A baffle plate installed in the electrolytic cell body; The two transverse ends of the barrier plate are fixed to the inner wall of the electrolytic cell, and there is a gap between the bottom surface of the barrier plate and the bottom of the electrolytic cell. The anode is installed inside the electrolytic cell, and the cathode is installed at the bottom of the electrolytic cell; The electrolytic cell is filled with molten electrolyte. Liquid aluminum is disposed inside the electrolytic cell. The molten electrolyte is a molten electrolyte with a density less than that of liquid aluminum. In the electrolytic cell, molten electrolyte is in the upper layer and liquid aluminum is in the lower layer.

2. The molten salt electrolysis preparation apparatus according to claim 1, characterized in that... The anodes in the electrolytic cell may be a single anode or multiple anodes.

3. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, The anode includes a graphite anode; When the anode in the electrolytic cell is a single anode, the single anode is immersed in molten electrolyte; The barrier plate is located below the single anode, and there is a certain gap between the top of the barrier plate and the bottom of the single anode; The top of the barrier plate is above the liquid surface of the liquid aluminum and is located in the molten electrolyte; The height of the spacing is 1 / 3 to 1 / 2 of the height of the liquid metal aluminum layer.

4. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, When there are multiple anodes in the electrolytic cell, the multiple anodes are immersed in molten electrolyte; The plurality of anodes are separated by an insulating material plate; The barrier plate is disposed between multiple anodes, and the insulating material plate is vertically disposed at the top of the barrier plate; The two transverse ends of the insulating material plate are connected to the inner wall of the insulating material; The top of the insulating material plate is higher than the liquid level of the molten electrolyte; The top of the barrier plate is below or equal to the liquid surface of the liquid aluminum and / or above the liquid surface of the liquid aluminum.

5. The molten salt electrolysis preparation apparatus according to claim 2, characterized in that, The molten electrolyte includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides; The molten electrolyte contains barium fluoride; The mass content of barium fluoride is less than 15% of the total mass of the molten electrolyte; The bottom of the inner wall of the insulating material is lower than the liquid surface of the liquid aluminum.

6. The molten salt electrolysis preparation apparatus according to claim 1, characterized in that, The preparation apparatus also includes a cathode current collector; The cathode current collector is disposed on the bottom surface of the electrolytic cell body; The preparation apparatus also includes a liquid aluminum-rare earth alloy outlet; The liquid aluminum-rare earth alloy outlet is located at the bottom of the electrolytic cell. The insulating material includes an insulating composite material in which the outer layer is graphite and the inner layer is one or more of aluminum oxide, boron nitride, silicon carbide, silicon nitride, and silicon carbide / silicon nitride.

7. A method for continuously preparing aluminum-rare earth alloys using the molten salt electrolysis preparation apparatus according to any one of claims 1 to 6, characterized in that, Includes the following steps: 1) Liquid aluminum and molten electrolyte are placed in the electrolytic cell of the molten salt electrolysis preparation device; The density of the molten electrolyte is less than that of liquid aluminum. 2) Turn on the molten salt electrolysis preparation device, add liquid aluminum metal into the electrolytic cell, put rare earth oxides into the electrolytic cell, and electrolyze to continuously prepare aluminum-rare earth alloys.

8. The method according to claim 7, characterized in that, The molten electrolyte includes alkali metal fluorides, alkaline earth metal fluorides, and rare earth fluorides; The molten electrolyte contains barium fluoride; The mass content of barium fluoride is less than 15% of the total mass of the molten electrolyte; The electrolysis temperature is 900~1100℃.

9. The method according to claim 7, characterized in that, The liquid aluminum metal is added to the electrolytic cell by being slowly added along the cell wall. The rate at which the liquid aluminum is added is equal to the rate at which the aluminum-rare earth alloy is released. The liquid aluminum is added to the electrolytic cell at a location far from the outlet of the liquid aluminum-rare earth alloy in the molten salt electrolysis preparation device. During the electrolysis process, an aluminum-rare earth alloy layer is formed at the bottom of the electrolytic cell. Then, raw materials are continuously added and aluminum-rare earth alloy is continuously released, thus achieving continuous preparation.

10. The method according to claim 7, characterized in that, The method for continuous preparation of aluminum-rare earth alloys is specifically a method for continuous preparation of aluminum-rare earth alloys with controllable composition. The content of rare earth elements in the aluminum-rare earth alloy is controlled by adjusting the current and the aluminum addition rate. The content of rare earth elements in the aluminum-rare earth alloy can be adjusted between 1% and 20%. The rare earth elements include one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

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